The severity of cardiac involvement in amyloidosis can be described by the degree of transmurality of late gadolinium enhancement in MRI.

Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis

BACKGROUND The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. METHODS AND RESULTS Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1-13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E', and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3-13.1; P<0.05). CONCLUSIONS There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after adjustment for known prognostic factors.

Familial amyloidosis: a study of 52 North American-born patients examined during a 30-year period.

Between 1961 and 1990, 52 patients with biopsy-proven familial amyloidosis born in North America were examined at the Mayo Clinic. At the time of diagnosis of familial amyloidosis, 83% of these patients had peripheral neuropathy, 33% had autonomic neuropathy, and 27% had cardiomyopathy. Renal disease was noted in fewer than 10%, and liver involvement was rare. The median age at diagnosis was 64 years. The sensitivity of various diagnostic biopsies was similar to that for primary amyloidosis: deposits of amyloid were found in 77 and 78% of the subcutaneous fat aspirates or rectal biopsy specimens, respectively, and in 41% of specimens of bone marrow. The median duration of survival of 5.8 years for patients with inherited amyloidosis was superior to that for patients with primary amyloidosis. When patients were stratified by organ involvement, the survival of patients with familial amyloidosis remained superior. The presence of cardiomyopathy and an interactive variable of age and the presence of autonomic neuropathy were powerful predictors of survival. Of the 52 patients, 22 died, 12 (55%) of cardiac failure or cardiac arrhythmia. Nine patients (41%) died of inanition in conjunction with progressive peripheral or autonomic neuropathy. Transthyretin was identified by immunohistochemical studies in 31 of the 34 tissue specimens tested. A transthyretin mutation was identified in 24 of the 31. A transthyretin mutation was found in five additional patients for whom tissue was unavailable for immunostaining.

Familial amyloidotic polyneuropathy: current and emerging treatment options for transthyretin-mediated amyloidosis

Transthyretin familial amyloid polyneuropathy (TTR-FAP) is a fatal clinical disorder characterized by extracellular deposition of abnormal fibrils derived from misfolded, normally soluble transthyretin (TTR) molecules. The disease is most commonly caused by a point mutation within the TTR gene inherited in an autosomal dominant fashion. Over 100 of such mutations have been identified, leading to destabilization of the physiological TTR tetramer. As a result, many monomers originate with a tendency for spontaneous conformational changes and self-aggregation. The main clinical feature of TTR-FAP is progressive sensorimotor and autonomic neuropathy. In the beginning, this polyneuropathy predominantly involves small unmyelinated nerve fibers with the result of dissociated sensory loss disproportionately affecting sensation of pain and temperature. Autonomic neuropathy typically accompanies sensory deficits early in the disease course. The symptoms include orthostatic hypotension, constipation alternating with diarrhea, erectile dysfunction, anhydrosis, and urinary retention or incontinence. Later, involvement of motor fibers causes rapidly progressive weakness and gait disturbances. In addition to the peripheral nervous system, the heart and the gut are frequently affected. Onset of symptoms is bimodal, with one peak at age 33 years (early onset) and another distinct peak in the sixth decade of life (late onset). The course of TTR-FAP is uniformly progressive and fatal. Death occurs an average of 10.8 years after the onset of symptoms in Portuguese patients, and 7.3 years in late-onset Japanese patients. Common causes include cachexia, cardiac failure, arrhythmia, and secondary infections. Liver transplantation is the standard therapy for patients who are in a clinical condition good enough to tolerate this intervention because it stops progression of neuropathy by removing the main source of mutant TTR. Recently, orally administered tafamidis meglumine has been approved by European authorities for treatment of FAP. The substance has been shown to stabilize the TTR tetramer, thereby improving the outcome of patients with TTR-FAP. Various other strategies have been studied in vitro to prevent TTR amyloidosis, including gene therapy, immunization, dissolution of TTR aggregates, and free radical scavengers, but none of them is ready for clinical use so far.

Therapeutic Clearance of Amyloid by Antibodies to Serum Amyloid P Component.

BACKGROUND The amyloid fibril deposits that cause systemic amyloidosis always contain the nonfibrillar normal plasma protein, serum amyloid P component (SAP). The drug (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC) efficiently depletes SAP from the plasma but leaves some SAP in amyloid deposits that can be specifically targeted by therapeutic IgG anti-SAP antibodies. In murine amyloid A type amyloidosis, the binding of these antibodies to the residual SAP in amyloid deposits activates complement and triggers the rapid clearance of amyloid by macrophage-derived multinucleated giant cells. METHODS We conducted an open-label, single-dose-escalation, phase 1 trial involving 15 patients with systemic amyloidosis. After first using CPHPC to deplete circulating SAP, we infused a fully humanized monoclonal IgG1 anti-SAP antibody. Patients with clinical evidence of cardiac involvement were not included for safety reasons. Organ function, inflammatory markers, and amyloid load were monitored. RESULTS There were no serious adverse events. Infusion reactions occurred in some of the initial recipients of larger doses of antibody; reactions were reduced by slowing the infusion rate for later patients. At 6 weeks, patients who had received a sufficient dose of antibody in relation to their amyloid load had decreased liver stiffness, as measured with the use of transient elastography. These patients also had improvements in liver function in association with a substantial reduction in hepatic amyloid load, as shown by means of SAP scintigraphy and measurement of extracellular volume by magnetic resonance imaging. A reduction in kidney amyloid load and shrinkage of an amyloid-laden lymph node were also observed. CONCLUSIONS Treatment with CPHPC followed by an anti-SAP antibody safely triggered clearance of amyloid deposits from the liver and some other tissues. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01777243.).

Early loss of interneurons and delayed subunit-specific changes in GABA(A)-receptor expression in a mouse model of mesial temporal lobe epilepsy.

Unilateral injection of kainic acid (KA) into the dorsal hippocampus of adult mice induces spontaneous recurrent partial seizures and replicates histopathological changes observed in human mesial temporal lobe epilepsy (MTLE) (Bouilleret V et al., Neuroscience 1999; 89:717-729). Alterations in pre- and postsynaptic components of GABAergic neurotransmission were investigated immunohistochemically at different time points (1-120 days) in this mouse model of MTLE. Markers of GABAergic interneurons (parvalbumin, calbindin-D28k, and calretinin), the type-1 GABA transporter (GAT1), and major GABA(A)-receptor subunits expressed in the hippocampal formation were analyzed. Acutely, KA injection produced a profound loss of hilar cells but only limited damage to CA1 and CA3 pyramidal cells. In addition, parvalbumin and calbindin-D28k staining of interneurons disappeared irreversibly in CA1 and dentate gyrus (DG), whereas calretinin staining was spared. The prominent GABA(A)-receptor alpha1 subunit staining of interneurons also disappeared after KA treatment, suggesting acute degeneration of these cells. Likewise, GAT1 immunoreactivity revealed degenerating terminals at 24 h post-KA in CA1 and DC and subsided almost completely thereafter. Loss of CA1 and, to a lesser extent, CA3 neurons became evident at 7-15 days post-KA. It was more accentuated after 1 month, accompanied by a corresponding reduction of GABA(A)-receptor staining. In contrast, DC granule cells were markedly enlarged and dispersed in the molecular layer and exhibited a prominent increase in GABA(A)-receptor subunit staining. After 4 months, the dorsal CA1 area was lost almost entirely, CA3 was reduced, and the DG represented most of the remaining dorsal hippocampal formation. No significant morphological alterations were detected contralaterally. These results suggest that loss of hilar cells and GABAergic neurons contributes to epileptogenesis in this model of MTLE. In contrast, long-term degeneration of pyramidal cells and granule cell dispersion may reflect distinct responses to recurrent seizures. Finally, GABA(A)-receptor upregulation in the DG may represent a compensatory response persisting for several months in epileptic mice.

Evaluation of systemic amyloidosis by scintigraphy with 123I-labeled serum amyloid P component.

BACKGROUND In systemic amyloidosis the distribution and progression of disease have been difficult to monitor, because they can be demonstrated only by biopsy. Serum amyloid P component (SAP) is a normal circulating plasma protein that is deposited on amyloid fibrils because of its specific binding affinity for them. We investigated whether labeled SAP could be used to locate amyloid deposits. METHODS Purified human SAP labeled with iodine-123 was given intravenously to 50 patients with biopsy-proved systemic amyloidosis--25 with the AL (primary) type and 25 with the AA (secondary) type--and to 26 control patients with disease and 10 healthy subjects. Whole-body images and regional views were obtained after 24 hours and read in a blinded fashion. RESULTS In the patients with amyloidosis the 123I-SAP was localized rapidly and specifically in amyloid deposits. The scintigraphic images obtained were characteristic and appeared to identify the extent of amyloid deposition in all 50 patients. There was no uptake of the 123I-SAP by the control patients and the healthy subjects. In all patients with AA amyloidosis the spleen was affected, whereas the scans showed uptake in the heart, skin, carpal region, and bone marrow only in patients with the AL type. Positive images were seen in six patients in whom biopsies had been negative or unsuccessful; in all six, amyloid was subsequently found on biopsy or at autopsy. Progressive amyloid deposition was observed in 9 of 11 patients studied serially. CONCLUSIONS Scintigraphy after the injection of 123I-SAP can be used for diagnosing, locating, and monitoring the extent of systemic amyloidosis.

T1 mapping for myocardial extracellular volume measurement by CMR: bolus only versus primed infusion technique.

OBJECTIVES The aim of this study was to determine the accuracy of the contrast "bolus only" T1 mapping cardiac magnetic resonance (CMR) technique for measuring myocardial extracellular volume fraction (ECV). BACKGROUND Myocardial ECV can be measured with T1 mapping before and after contrast agent if the contrast agent distribution between blood/myocardium is at equilibrium. Equilibrium distribution can be achieved with a primed contrast infusion (equilibrium contrast-CMR [EQ-CMR]) or might be approximated by the dynamic equilibration achieved by delayed post-bolus measurement. This bolus only approach is highly attractive, but currently limited data support its use. We compared the bolus only technique with 2 independent standards: collagen volume fraction (CVF) from myocardial biopsy in aortic stenosis (AS); and the infusion technique in 5 representative conditions. METHODS One hundred forty-seven subjects were studied: healthy volunteers (n = 50); hypertrophic cardiomyopathy (n = 25); severe AS (n = 22); amyloid (n = 20); and chronic myocardial infarction (n = 30). Bolus only (at 15 min) and infusion ECV measurements were performed and compared. In 18 subjects with severe AS the results were compared with histological CVF. RESULTS The ECV by both techniques correlated with histological CVF (n = 18, r² = 0.69, p < 0.01 vs. r² = 0.71, p < 0.01, p = 0.42 for comparison). Across health and disease, there was strong correlation between the techniques (r² = 0.97). However, in diseases of high ECV (amyloid, hypertrophic cardiomyopathy late gadolinium enhancement, and infarction), Bland-Altman analysis indicates the bolus only technique has a consistent and increasing offset, giving a higher value for ECVs above 0.4 (mean difference ± limit of agreement for ECV <0.4 = -0.004 ± 0.037 vs. ECV >0.4 = 0.040 ± 0.075, p < 0.001). CONCLUSIONS Bolus only, T1 mapping-derived ECV measurement is sufficient for ECV measurement across a range of cardiac diseases, and this approach is histologically validated in AS. However, when ECV is >0.4, the bolus only technique consistently measures ECV higher compared with infusion.

Neuronal origin of a cerebral amyloid: neurofibrillary tangles of Alzheimer's disease contain the same protein as the amyloid of plaque cores and blood vessels.

The protein component of Alzheimer's disease amyloid [neurofibrillary tangles (NFT), amyloid plaque core and congophilic angiopathy] is an aggregated polypeptide with a subunit mass of 4 kd (the A4 monomer). Based on the degree of N-terminal heterogeneity, the amyloid is first deposited in the neuron, and later in the extracellular space. Using antisera raised against synthetic peptides, we show that the N terminus of A4 (residues 1-11) contains an epitope for neurofibrillary tangles, and the inner region of the molecule (residues 11-23) contains an epitope for plaque cores and vascular amyloid. The non-protein component of the amyloid (aluminum silicate) may form the basis for the deposition or amplification (possible self-replication) of the aggregated amyloid protein. The amyloid of Alzheimer's disease is similar in subunit size, composition but not sequence to the scrapie-associated fibril and its constituent polypeptides. The sequence and composition of NFT are not homologous to those of any of the known components of normal neurofilaments.

Oral fingolimod (FTY720) for relapsing multiple sclerosis.

BACKGROUND Fingolimod (FTY720) is a new oral immunomodulating agent under evaluation for the treatment of relapsing multiple sclerosis. METHODS We randomly assigned 281 patients to receive oral fingolimod, at a dose of 1.25 mg or 5.0 mg, or a placebo once daily, and we followed these patients for 6 months with magnetic resonance imaging (MRI) and clinical evaluations (core study, months 0 to 6). The primary end point was the total number of gadolinium-enhanced lesions recorded on T(1)-weighted MRI at monthly intervals for 6 months. In an extension study in which the investigators and patients remained unaware of the dose assignments (months 7 to 12), patients who received placebo underwent randomization again to one of the fingolimod doses. RESULTS A total of 255 patients completed the core study. The median total number of gadolinium-enhanced lesions on MRI was lower with 1.25 mg of fingolimod (1 lesion, P<0.001) and 5.0 mg of fingolimod (3 lesions, P=0.006) than with placebo (5 lesions). The annualized relapse rate was 0.77 in the placebo group, as compared with 0.35 in the group given 1.25 mg of fingolimod (P=0.009) and 0.36 in the group given 5.0 mg of fingolimod (P=0.01). For the 227 patients who completed the extension study, the number of gadolinium-enhanced lesions and relapse rates remained low in the groups that received continuous fingolimod, and both measures decreased in patients who switched from placebo to fingolimod. Adverse events included nasopharyngitis, dyspnea, headache, diarrhea, and nausea. Clinically asymptomatic elevations of alanine aminotransferase levels were more frequent with fingolimod (10 to 12%, vs. 1% in the placebo group). One case of the posterior reversible encephalopathy syndrome occurred in the 5.0-mg group. Fingolimod was also associated with an initial reduction in the heart rate and a modest decrease in the forced expiratory volume in 1 second. CONCLUSIONS In this proof-of-concept study, fingolimod reduced the number of lesions detected on MRI and clinical disease activity in patients with multiple sclerosis. Evaluation in larger, longer-term studies is warranted. (Clinicaltrials.gov numbers, NCT00333138 [core study] and NCT00235430 [ClinicalTrials.gov] [extension].).

Phagocytosis and deposition of vascular beta-amyloid in rat brains injected with Alzheimer beta-amyloid.

The presence of extracellular deposits of beta-amyloid protein in the brain is a hallmark of Alzheimer's disease (AD). In an effort to determine the effect of amyloid in an animal model, the authors injected amyloid cores isolated from AD brains into the cortex and hippocampus of rats. Lipofuscin, a major contaminant of the plaque core preparation, was injected on the contralateral side and used as a control to induce an analogous phagocytic cell response. Rats were sacrificed 2 days, 7 days, and 1 month after injection and amyloid located by four histochemical techniques. Amyloid and lipofuscin move from the site of injection into otherwise undamaged neuropil, persist for at least 1 month and are both associated with increases in glial fibrillary acidic protein and microglia (OX-42) staining. By 1 week, many of the amyloid cores are ingested by phagocytes. Some of the beta-amyloid-containing phagocytes migrate to the vessels and to the ventricles, and by 1 month, a significant amount of the amyloid is directly associated with the vessels. This suggests that phagocytic cells can internalize exogenous amyloid and attempt to clear it from the central nervous system (CNS). Therefore, the observed distribution of amyloid is not necessarily the initial site of deposition.

Summary

The genetic diseases Hutchinson-Gilford progeria syndrome (HGPS) and restrictive dermopathy (RD) arise from accumulation of farnesylated prelamin A because of defects in the lamin A maturation pathway. Both of these diseases exhibit symptoms that can be viewed as accelerated aging. The mechanism by which accumulation of farnesylated prelamin A leads to these accelerated aging phenotypes is not understood. Here we present evidence that in HGPS and RD fibroblasts, DNA damage checkpoints are persistently activated because of the compromise in genomic integrity. Inactivation of checkpoint kinases Ataxia-telangiectasia-mutated (ATM) and ATR (ATM- and Rad3-related) in these patient cells can partially overcome their early replication arrest. Treatment of patient cells with a protein farnesyltransferase inhibitor (FTI) did not result in reduction of DNA double-strand breaks and damage checkpoint signaling, although the treatment significantly reversed the aberrant shape of their nuclei. This suggests that DNA damage accumulation and aberrant nuclear morphology are independent phenotypes arising from prelamin A accumulation in these progeroid syndromes. Since DNA damage accumulation is an important contributor to the symptoms of HGPS, our results call into question the possibility of treatment of HGPS with FTIs alone.

Amyloid accumulation is a late event in sporadic Alzheimer's disease-like pathology in nontransgenic rats

The amyloid cascade hypothesis posits that deposition of the amyloid β (Aβ) peptide in the brain is a key event in the initiation of Alzheimer's disease (AD). Nonetheless, it now seems increasingly unlikely that amyloid toxicity is the cause of sporadic AD, which leads to cognitive decline. Here, using accelerated-senescence nontransgenic OXYS rats, we confirmed that aggregation of Aβ is a later event in AD-like pathology. We showed that an age-dependent increase in the levels of Aβ₁₋₄₂ and extracellular Aβ deposits in the brain of OXYS rats occur later than do synaptic losses, neuronal cell death, mitochondrial structural abnormalities, and hyperphosphorylation of the tau protein. We identified the variants of the genes that are strongly associated with the risk of either late-onset or early-onset AD, including App, Apoe4, Bace1, Psen1, Psen2, and Picalm. We found that in OXYS rats nonsynonymous SNPs were located only in the genes Casp3 and Sorl1. Thus, we present proof that OXYS rats may be a model of sporadic AD. It is possible that multiple age-associated pathological processes may precede the toxic amyloid accumulation, which in turn triggers the final stage of the sporadic form of AD and becomes a hallmark event of the disease.

Incidence of cancer after immunosuppressive treatment for heart transplantation.

Prolonged or intensive immunosuppressive therapy used after organ transplantation is complicated by an increased incidence of cancer. Striking differences in incidence are observed in heart and heart-lung transplant recipients when compared with renal transplant patients. The most significant increase was in the incidence of lymphomas in cardiac versus renal patients. Moreover, a two-fold greater increase of all neoplasms was found in cardiac recipients, with nearly a six-fold increase in visceral tumors. Several factors may account for these differences. In cardiac allograft recipients, intensive immunosuppression is frequently used to reverse acute rejection and the highest number of cardiac transplants was performed in the era of polypharmacy, usually consisting of triple therapy.

Prion-induced amyloid heart disease with high blood infectivity in transgenic mice.

We investigated extraneural manifestations in scrapie-infected transgenic mice expressing prion protein lacking the glycophosphatydylinositol membrane anchor. In the brain, blood, and heart, both abnormal protease-resistant prion protein (PrPres) and prion infectivity were readily detected by immunoblot and by inoculation into nontransgenic recipients. The titer of infectious scrapie in blood plasma exceeded 10(7) 50% infectious doses per milliliter. The hearts of these transgenic mice contained PrPres-positive amyloid deposits that led to myocardial stiffness and cardiac disease.

A new look at the heart in diabetes mellitus: from ailing to failing

This review discusses some of the mechanisms inherent in diabetes that predispose patients to increased cardiac morbidity and mortality. Single photon emission computerized tomography or photon emission tomography with radioactive labeled analogues of norepinephrine have shown that cardiac sympathetic dysfunction and incompetence are early and also late abnormalities in patients with Type I (insulin-dependent) and Type II (non-insulin-dependent) diabetes mellitus. Furthermore, myocardial blood flow assessment with photon emission tomography has shown that in patients without myocardial perfusion deficits, endothelial-dependent vasodilatation is severely reduced in relation to cardiac sympathetic dysfunction. In addition, signs of endothelial activation have also been found early in patients with Type I and Type II diabetes in whom vascular disease has not been clinically detected. This activation in conjunction with glycaemic control is important in determining macrovascular mortality. Cardiac sympathetic dysfunction is partially restored to normal with near normalisation of glycaemia. Interpretations. Recently unrecognized “subtle” changes predispose the heart to failure, after ischaemia-induced remodelling, and arteriosclerotic plaques to instability and rupture. These changes act in conjunction with effects, driven by hyperglycaemia and diabetes, on the endothelium of large blood vessels, e. g. on nitric oxide release or on protein kinase-C β activation. Meticulous glucose control early on and rapid recompensation of hyperglycaemia in patients with acute coronary syndrome are part of a successful intensive multifactorial approach to prevent the heart in diabetes converting from ailing to failing. [Diabetologia (2000) 43: 1455–1469]

DNA Methylation in the Human Cerebral Cortex Is Dynamically Regulated throughout the Life Span and Involves Differentiated Neurons

The role of DNA cytosine methylation, an epigenetic regulator of chromatin structure and function, during normal and pathological brain development and aging remains unclear. Here, we examined by MethyLight PCR the DNA methylation status at 50 loci, encompassing primarily 5′ CpG islands of genes related to CNS growth and development, in temporal neocortex of 125 subjects ranging in age from 17 weeks of gestation to 104 years old. Two psychiatric disease cohorts—defined by chronic neurodegeneration (Alzheimer's) or lack thereof (schizophrenia)—were included. A robust and progressive rise in DNA methylation levels across the lifespan was observed for 8/50 loci (GABRA2, GAD1, HOXA1, NEUROD1, NEUROD2, PGR, STK11, SYK) typically in conjunction with declining levels of the corresponding mRNAs. Another 16 loci were defined by a sharp rise in DNA methylation levels within the first few months or years after birth. Disease-associated changes were limited to 2/50 loci in the Alzheimer's cohort, which appeared to reflect an acceleration of the age-related change in normal brain. Additionally, methylation studies on sorted nuclei provided evidence for bidirectional methylation events in cortical neurons during the transition from childhood to advanced age, as reflected by significant increases at 3, and a decrease at 1 of 10 loci. Furthermore, the DNMT3a de novo DNA methyl-transferase was expressed across all ages, including a subset of neurons residing in layers III and V of the mature cortex. Therefore, DNA methylation is dynamically regulated in the human cerebral cortex throughout the lifespan, involves differentiated neurons, and affects a substantial portion of genes predominantly by an age-related increase.

Myocardial muscarinic receptor upregulation and normal response to isoproterenol in denervated hearts by familial amyloid polyneuropathy.

BACKGROUND Patients with familial amyloid polyneuropathy, a rare hereditary form of amyloidosis, have progressive autonomic neuropathy. The disease usually does not induce heart failure but is associated with sudden death, conduction disturbances, and an increased risk of complications during anesthesia. Although cardiac sympathetic denervation has been clearly demonstrated, the postsynaptic status of the cardiac autonomic nervous system remains unelucidated. METHODS AND RESULTS Twenty-one patients were studied (age, 39+/-11 years; normal coronary arteries; left ventricular ejection fraction 68+/-9%). To evaluate the density and affinity constants of myocardial muscarinic receptors, PET with (11)C-MQNB (methylquinuclidinyl benzilate), a specific hydrophilic antagonist, was used. Cardiac beta-receptor functional efficiency was studied by the heart rate (HR) response to intravenous infusion of isoproterenol (5 minutes after 2 mg of atropine, 5, 10, and 15 ng/kg per minute during 5 minutes per step). The mean muscarinic receptor density was higher in patients than in control subjects (B'(max), 35.5+/-8.9 versus 26.1+/-6.7 pmol/mL, P=0.003), without change in receptor affinity. The increase in HR after injection of atropine as well as of MQNB was lower in patients compared with control subjects despite a similar basal HR (DeltaHR after atropine, 11+/-21% versus 62+/-17%; P<0.001), consistent with parasympathetic denervation. Incremental infusion of isoproterenol induced a similar increase in HR in patients and control subjects. CONCLUSIONS Cardiac autonomic denervation in familial amyloid polyneuropathy results in an upregulation of myocardial muscarinic receptors but without change in cardiac beta-receptor responsiveness to catecholamines.

Characteristics of medial temporal lobe epilepsy: II. Interictal and ictal scalp electroencephalography, neuropsychological testing, neuroimaging, surgical results, and pathology.

Sixty-seven patients with temporal lobe epilepsy without circumscribed, potentially epileptogenic lesions, who were studied with intracranial electrodes and who became seizure free following temporal lobectomy were retrospectively evaluated with regard to preoperative scalp electroencephalographic (EEG) findings, neuropsychological test results, neuroimaging findings, results of surgery, and pathology of resected tissue. Interictal scalp EEG showed paroxysmal abnormalities during prolonged monitoring in 64 patients (96%). These were localized in the anterior temporal region in 60 (94%) of these 64 patients. Bilateral independent paroxysmal activity occurred in 42% of the patients and was preponderant over the side of seizure origin in half. Ictal EEG changes were rarely detected at the time of clinical seizure onset, but lateralized buildup of rhythmic seizure activity during the seizure occurred in 80% of patients. In 13%, the scalp EEG seizure buildup was, however, contralateral to the side of seizure origin as subsequently determined by depth EEG and curative surgery. Lateralized postictal slowing, when present, was a very reliable lateralizing finding. Neuropsychological testing provided lateralizing findings concordant with the side of seizure origin in 73% of patients. When neuropsychological testing produced discordant results or nonlateralizing findings, those patients were usually found to have right temporal seizure origin. Intracarotid amobarbital (Amytal) testing demonstrated absent or marginal memory functions on the side of seizure onset in 63% of patients, but 26 patients (37%) had bilaterally intact memory. In those patients who had magnetic resonance imaging, it was very sensitive in detecting subtle medial temporal abnormalities. These abnormalities were present in 23 of 28 magnetic resonance images, and corresponded with mesial temporal sclerosis on pathological examination in all but 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring effectiveness and safety of Tafamidis in transthyretin amyloidosis in Italy: a longitudinal multicenter study in a non-endemic area

Tafamidis is a transthyretin (TTR) stabilizer able to prevent TTR tetramer dissociation. There have been a few encouraging studies on Tafamidis efficacy in early-onset inherited transthyretin amyloidosis (ATTR) due to Val30Met mutation. However, less is known about its efficacy in later disease stages and in non-Val30Met mutations. We performed a multi-center observational study on symptomatic ATTR patients prescribed to receive Tafamidis. We followed up patients according to a standardized protocol including general medical, cardiological and neurological assessments at baseline and every 6 months up to 3 years. Sixty-one (42 males) patients were recruited. Only 28 % of enrolled subjects had the common Val30Met mutation, mean age of onset was remarkably late (59 years) and 18 % was in advanced disease stage at study entry. Tafamidis proved safe and well-tolerated. One-third of patients did not show significant progression along 36 months, independently from mutation type and disease stage. Neurological function worsened particularly in the first 6 months but progression slowed significantly thereafter. Autonomic function remained stable in 33 %, worsened in 56 % and improved in 10 %. Fifteen percent of patients showed cardiac disease progression and 30 % new onset of cardiomyopathy. Overall, Tafamidis was not able to prevent functional progression of the disease in 23 (43 %) subjects, including 16 patients who worsened in their walking ability and 12 patients who reached a higher NYHA score during the follow-up period. A higher mBMI at baseline was associated with better preservation of neurological function. In conclusion, neuropathy and cardiomyopathy progressed in a significant proportion of patients despite treatment. However, worsening of neurological function slowed after the first 6 months and also subjects with more advanced neuropathy, as well as patients with non-Val30Met mutation, benefited from treatment. Body weight preservation is an important favorable prognostic factor.

Stem cell transplantation in patients with autonomic neuropathy due to primary (AL) amyloidosis.

OBJECTIVES Patients with AL amyloidosis can benefit from high-dose chemotherapy and autologous stem cell transplantation (ASCT). Transplantation can be challenging due to fluid shifts, sepsis, and cardiac dysrhythmias. Amyloidosis may present with autonomic neuropathy (AN) that renders peritransplant care problematic. The purpose of this study was to determine the outcome of patients with AN during and after ASCT. METHODS We performed a case-control study of patients with AL amyloidosis with associated AN and compared them to a large matched cohort without AN who also underwent ASCT. RESULTS We identified 13 patients with AN who underwent ASCT and a matched control group of 95 patients without AN. Patients with AN had more organs involved (median 2.5 vs 1, p < 0.001) and the conditioning dose of melphalan was often reduced by 30% compared to controls without AN (p = 0.0015). Median duration of hospitalization was similar for both cohorts, as were engraftment kinetics. Atrial fibrillation occurred in all patients with AN but in only 1 control patient (p < 0.0001). Median overall survival (OS) for patients with AN was 29 months but >60 months for controls (p < 0.0001). On univariate analysis, cardiac involvement (p = 0.0132), AN (p = 0.0011), glomerular filtration rate (p = 0.038), number of organs involved (p = 0.0064), and NT-pro-BNP (p = 0.039) all had an impact on OS. On multivariate analysis, AN retained an independent adverse impact on OS. CONCLUSIONS Patients with autonomic neuropathy secondary to AL amyloidosis can undergo autologous stem cell transplantation with relative safety. Autonomic neuropathy is an independent, adverse determinant of survival in these patients.

Review of the secondary injury theory of acute spinal cord trauma with emphasis on vascular mechanisms.

In patients with spinal cord injury, the primary or mechanical trauma seldom causes total transection, even though the functional loss may be complete. In addition, biochemical and pathological changes in the cord may worsen after injury. To explain these phenomena, the concept of the secondary injury has evolved for which numerous pathophysiological mechanisms have been postulated. This paper reviews the concept of secondary injury with special emphasis on vascular mechanisms. Evidence is presented to support the theory of secondary injury and the hypothesis that a key mechanism is posttraumatic ischemia with resultant infarction of the spinal cord. Evidence for the role of vascular mechanisms has been obtained from a variety of models of acute spinal cord injury in several species. Many different angiographic methods have been used for assessing microcirculation of the cord and for measuring spinal cord blood flow after trauma. With these techniques, the major systemic and local vascular effects of acute spinal cord injury have been identified and implicated in the etiology of secondary injury. The systemic effects of acute spinal cord injury include hypotension and reduced cardiac output. The local effects include loss of autoregulation in the injured segment of the spinal cord and a marked reduction of the microcirculation in both gray and white matter, especially in hemorrhagic regions and in adjacent zones. The microcirculatory loss extends for a considerable distance proximal and distal to the site of injury. Many studies have shown a dose-dependent reduction of spinal cord blood flow varying with the severity of injury, and a reduction of spinal cord blood flow which worsens with time after injury. The functional deficits due to acute spinal cord injury have been measured electrophysiologically with techniques such as motor and somatosensory evoked potentials and have been found proportional to the degree of posttraumatic ischemia. The histological effects include early hemorrhagic necrosis leading to major infarction at the injury site. These posttraumatic vascular effects can be treated. Systemic normotension can be restored with volume expansion or vasopressors, and spinal cord blood flow can be improved with dopamine, steroids, nimodipine, or volume expansion. The combination of nimodipine and volume expansion improves posttraumatic spinal cord blood flow and spinal cord function measured by evoked potentials. These results provide strong evidence that posttraumatic ischemia is an important secondary mechanism of injury, and that it can be counteracted.

Acute kidney injury and chronic kidney disease: an integrated clinical syndrome.

The previous conventional wisdom that survivors of acute kidney injury (AKI) tend to do well and fully recover renal function appears to be flawed. AKI can cause end-stage renal disease (ESRD) directly, and increase the risk of developing incident chronic kidney disease (CKD) and worsening of underlying CKD. In addition, severity, duration, and frequency of AKI appear to be important predictors of poor patient outcomes. CKD is an important risk factor for the development and ascertainment of AKI. Experimental data support the clinical observations and the bidirectional nature of the relationships between AKI and CKD. Reductions in renal mass and nephron number, vascular insufficiency, cell cycle disruption, and maladaptive repair mechanisms appear to be important modulators of progression in patients with and without coexistent CKD. Distinction between AKI and CKD may be artificial. Consideration should be given to the integrated clinical syndrome of diminished GFR, with acute and chronic stages, where spectrum of disease state and outcome is determined by host factors, including the balance of adaptive and maladaptive repair mechanisms over time. Physicians must provide long-term follow-up to patients with first episodes of AKI, even if they presented with normal renal function.

Frontal stroke syndromes.

The frontal lobe is the largest lobe of the brain, and it is thus commonly involved in stroke. Moreover, almost one in five strokes is limited to the prerolandic areas. This high frequency of anatomical involvement is in sharp contrast with the apparent rarity of clinical frontal dysfunction in stroke. It is remarkable that frontal behavioral syndromes have been rather uncommonly reported in patients with stroke as compared to patients with other diseases, such as brain tumor. This fact is paradoxical, because an acute process (stroke) is expected to yield more clinical dysfunction than a more chronic disease (tumor). A volume effect may be the main factor leading to this phenomenon. Another interesting aspect of frontal strokes is the contribution of so-called 'silent' strokes, the recurrence of which may nevertheless lead to intellectual decline and compromise recovery from another stroke with more specific neurologic dysfunction. The contribution of stroke to understanding of frontal lobe dysfunction is important, because of the focal nature of this disease, and great opportunity for clinical-topographic classification correlations. One of the first modern attempts to develop a clinical-topographic classification of frontal lobe lesions came from the school of Luria, who tried to delineate three main types of frontal lobe syndromes (premotor syndrome, prefrontal syndrome, medial-frontal syndrome). Recent anatomic correlates using MRI make it possible to improve this classification. We suggest considering six main clinical-anatomic frontal stroke syndromes: (1) prefrontal; (2) premotor; (3) superior medial; (4) orbital-medial; (5) basal forebrain; (6) white matter. Finally, another fascinating topic relates to frontal lobe symptomatology due to stroke sparing the frontal cortex or white matter. This occurs mainly in three instances: lenticulo-capsular stroke, caudate stroke, and thalamic stroke. Studies using blood flow or metabolism measurements suggest that diaschisis (frontal lobe dysfunction from a remote lesion) may play a role. We believe that this is more likely to be related to dynamic interruption of complex circuitry than to static frontal lobe deactivation.

Mechanisms of progression and regression of renal lesions of chronic nephropathies and diabetes.

The incidence of chronic kidney diseases is increasing worldwide, and these conditions are emerging as a major public health problem. While genetic factors contribute to susceptibility and progression of renal disease, proteinuria has been claimed as an independent predictor of outcome. Reduction of urinary protein levels by various medications and a low-protein diet limits renal function decline in individuals with nondiabetic and diabetic nephropathies to the point that remission of the disease and regression of renal lesions have been observed in experimental animals and even in humans. In animal models, regression of glomerular structural changes is associated with remodeling of the glomerular architecture. Instrumental to this discovery were 3D reconstruction studies of the glomerular capillary tuft, which allowed the quantification of sclerosis volume reduction and capillary regeneration upon treatment. Regeneration of capillary segments might result from the contribution of resident cells, but progenitor cells of renal or extrarenal origin may also have a role. This review describes recent advances in our understanding of the mechanisms and mediators underlying renal tissue repair ultimately responsible for regression of renal injury.

A three-dimensional human neural cell culture model of Alzheimer’s disease

Alzheimer’s disease is the most common form of dementia, characterized by two pathological hallmarks: amyloid-β plaques and neurofibrillary tangles. The amyloid hypothesis of Alzheimer’s disease posits that the excessive accumulation of amyloid-β peptide leads to neurofibrillary tangles composed of aggregated hyperphosphorylated tau. However, to date, no single disease model has serially linked these two pathological events using human neuronal cells. Mouse models with familial Alzheimer’s disease (FAD) mutations exhibit amyloid-β-induced synaptic and memory deficits but they do not fully recapitulate other key pathological events of Alzheimer’s disease, including distinct neurofibrillary tangle pathology. Human neurons derived from Alzheimer’s disease patients have shown elevated levels of toxic amyloid-β species and phosphorylated tau but did not demonstrate amyloid-β plaques or neurofibrillary tangles. Here we report that FAD mutations in β-amyloid precursor protein and presenilin 1 are able to induce robust extracellular deposition of amyloid-β, including amyloid-β plaques, in a human neural stem-cell-derived three-dimensional (3D) culture system. More importantly, the 3D-differentiated neuronal cells expressing FAD mutations exhibited high levels of detergent-resistant, silver-positive aggregates of phosphorylated tau in the soma and neurites, as well as filamentous tau, as detected by immunoelectron microscopy. Inhibition of amyloid-β generation with β- or γ-secretase inhibitors not only decreased amyloid-β pathology, but also attenuated tauopathy. We also found that glycogen synthase kinase 3 (GSK3) regulated amyloid-β-mediated tau phosphorylation. We have successfully recapitulated amyloid-β and tau pathology in a single 3D human neural cell culture system. Our unique strategy for recapitulating Alzheimer’s disease pathology in a 3D neural cell culture model should also serve to facilitate the development of more precise human neural cell models of other neurodegenerative disorders.

Functional screening identifies miRNAs inducing cardiac regeneration

In mammals, enlargement of the heart during embryonic development is primarily dependent on the increase in cardiomyocyte numbers. Shortly after birth, however, cardiomyocytes stop proliferating and further growth of the myocardium occurs through hypertrophic enlargement of the existing myocytes. As a consequence of the minimal renewal of cardiomyocytes during adult life, repair of cardiac damage through myocardial regeneration is very limited. Here we show that the exogenous administration of selected microRNAs (miRNAs) markedly stimulates cardiomyocyte proliferation and promotes cardiac repair. We performed a high-content microscopy, high-throughput functional screening for human miRNAs that promoted neonatal cardiomyocyte proliferation using a whole-genome miRNA library. Forty miRNAs strongly increased both DNA synthesis and cytokinesis in neonatal mouse and rat cardiomyocytes. Two of these miRNAs (hsa-miR-590 and hsa-miR-199a) were further selected for testing and were shown to promote cell cycle re-entry of adult cardiomyocytes ex vivo and to promote cardiomyocyte proliferation in both neonatal and adult animals. After myocardial infarction in mice, these miRNAs stimulated marked cardiac regeneration and almost complete recovery of cardiac functional parameters. The miRNAs identified hold great promise for the treatment of cardiac pathologies consequent to cardiomyocyte loss.

Rapamycin treatment augments motor neuron degeneration in SOD1(G93A) mouse model of amyotrophic lateral sclerosis.

Aberrant protein misfolding may contribute to the pathogenesis of amyotrophic lateral sclerosis (ALS) but the detailed mechanisms are largely unknown. Our previous study has shown that autophagy is altered in the mouse model of ALS. In the present study, we systematically investigated the correlation of the autophagic alteration with the motor neurons (MNs) degeneration in the ALS mice. We have demonstrated that the autophagic protein marker LC3-II is markedly and specifically increased in the spinal cord MNs of the ALS mice. Electron microscopy and immunochemistry studies have shown that autophagic vacuoles are significantly accumulated in the dystrophic axons of spinal cord MNs of the ALS mice. All these changes in the ALS mice appear at the age of 90 d when the ALS mice display modest clinical symptoms; and they become prominent at the age of 120 d. The clinical symptoms are correlated with the progression of MNs degeneration. Moreover, we have found that p62/SQSTM1 is accumulated progressively in the spinal cord, indicating that the possibility of impaired autophagic flux in the SOD1(G93A) mice. Furthermore, to our surprise, we have found that treatment with autophagy enhancer rapamycin accelerates the MNs degeneration, shortens the life span of the ALS mice, and has no obvious effects on the accumulation of SOD1 aggregates. In addition, we have demonstrated that rapamycin treatment in the ALS mice causes more severe mitochondrial impairment, higher Bax levels and greater caspase-3 activation. These findings suggest that selective degeneration of MNs is associated with the impairment of the autophagy pathway and that rapamycin treatment may exacerbate the pathological processing through apoptosis and other mechanisms in the ALS mice.

Engraftment of engineered ES cell–derived cardiomyocytes but not BM cells restores contractile function to the infarcted myocardium

Cellular cardiomyoplasty is an attractive option for the treatment of severe heart failure. It is, however, still unclear and controversial which is the most promising cell source. Therefore, we investigated and examined the fate and functional impact of bone marrow (BM) cells and embryonic stem cell (ES cell)–derived cardiomyocytes after transplantation into the infarcted mouse heart. This proved particularly challenging for the ES cells, as their enrichment into cardiomyocytes and their long-term engraftment and tumorigenicity are still poorly understood. We generated transgenic ES cells expressing puromycin resistance and enhanced green fluorescent protein cassettes under control of a cardiac-specific promoter. Puromycin selection resulted in a highly purified (>99%) cardiomyocyte population, and the yield of cardiomyocytes increased 6–10-fold because of induction of proliferation on purification. Long-term engraftment (4–5 months) was observed when co-transplanting selected ES cell–derived cardiomyocytes and fibroblasts into the injured heart of syngeneic mice, and no teratoma formation was found (n = 60). Although transplantation of ES cell–derived cardiomyocytes improved heart function, BM cells had no positive effects. Furthermore, no contribution of BM cells to cardiac, endothelial, or smooth muscle neogenesis was detected. Hence, our results demonstrate that ES-based cell therapy is a promising approach for the treatment of impaired myocardial function and provides better results than BM-derived cells.

Quality of life in patients with advanced heart failure.

Although evaluation of the treatment of congestive heart failure is usually based on objective clinical outcomes, patient self-assessment is increasingly recognized as an important component of evaluation. A study was designed to measure the quality of life of 134 patients with symptoms of advanced heart failure who were being evaluated for possible heart transplantation. The patients' quality of life was assessed using a mix of subjective and objective measures, including functional status, physical symptoms, emotional state, and psychosocial adaptation. There was no significant relationship between patients' cardiac ejection fraction and any quality-of-life measures; however, the results of a 6-minute walking test, New York Heart Association classification, and self-reported functional status were all significantly correlated with psychosocial adjustment. Self-reported functional status, depression, and hostility accounted for 43% of the variance in total psychosocial adjustment to illness. These findings support the inclusion of quality of life as an outcome measure in any evaluation of treatment efficacy and suggest that interventions to improve the quality of life of patients with advanced heart failure need to be targeted at reducing depression and hostility and increasing daily activity levels.

Hypoxia in cancer: significance and impact on clinical outcome

Hypoxia, a characteristic feature of locally advanced solid tumors, has emerged as a pivotal factor of the tumor (patho-)physiome since it can promote tumor progression and resistance to therapy. Hypoxia represents a “Janus face” in tumor biology because (a) it is associated with restrained proliferation, differentiation, necrosis or apoptosis, and (b) it can also lead to the development of an aggressive phenotype. Independent of standard prognostic factors, such as tumor stage and nodal status, hypoxia has been suggested as an adverse prognostic factor for patient outcome. Studies of tumor hypoxia involving the direct assessment of the oxygenation status have suggested worse disease-free survival for patients with hypoxic cervical cancers or soft tissue sarcomas. In head & neck cancers the studies suggest that hypoxia is prognostic for survival and local control. Technical limitations of the direct O2 sensing technique have prompted the use of surrogate markers for tumor hypoxia, such as hypoxia-related endogenous proteins (e.g., HIF-1α, GLUT-1, CA IX) or exogenous bioreductive drugs. In many—albeit not in all—studies endogenous markers showed prognostic significance for patient outcome. The prognostic relevance of exogenous markers, however, appears to be limited. Noninvasive assessment of hypoxia using imaging techniques can be achieved with PET or SPECT detection of radiolabeled tracers or with MRI techniques (e.g., BOLD). Clinical experience with these methods regarding patient prognosis is so far only limited. In the clinical studies performed up until now, the lack of standardized treatment protocols, inconsistencies of the endpoints characterizing the oxygenation status and methodological differences (e.g., different immunohistochemical staining procedures) may compromise the power of the prognostic parameter used.

MRI in the diagnosis of MS: a prospective study with comparison of clinical evaluation, evoked potentials, oligoclonal banding, and CT.

We compared the diagnostic capabilities of MRI to CT, evoked potentials (EP), and CSF oligoclonal banding analysis in a prospective evaluation of 200 patients with suspected multiple sclerosis (MS). MRI was the best method for demonstrating dissemination in space. An abnormal appropriate EP in monosymptomatic disease was usually supported by MRI and CSF analysis as being predictive of MS as a clinical diagnosis. A normal appropriate EP study was not satisfactory because MRI and CSF analysis often did not support a diagnosis of non-MS. When there is agreement between three of these paraclinical studies, the diagnosis of MS is probably unequivocal. For use in research studies, laboratory-supported definite MS (LSDMS) could be diagnosed in 85 patients of the total 200 (42.5%), in 19/38 (50%) of optic neuritis (ON) patients, and in 24/52 (46%) of chronic progressive myelopathy (CPM) patients. MRI was 100% successful in identifying patients who qualified for LSDMS in the ON and CPM groups. In a short follow-up (less than 1 year), 19/200 (10%) went on to develop clinically definite MS (CDMS), and MRI predicted that diagnosis in 18/19 (95%). Only long-term follow-up will show how well these studies and the category of LSDMS predict the development of CDMS. The clinical diagnosis of MS (CDMS), even though only 95% accurate, must remain the gold standard.

Biochemical Properties of Highly Neuroinvasive Prion Strains

Infectious prions propagate from peripheral entry sites into the central nervous system (CNS), where they cause progressive neurodegeneration that ultimately leads to death. Yet the pathogenesis of prion disease can vary dramatically depending on the strain, or conformational variant of the aberrantly folded and aggregated protein, PrP(Sc). Although most prion strains invade the CNS, some prion strains cannot gain entry and do not cause clinical signs of disease. The conformational basis for this remarkable variation in the pathogenesis among strains is unclear. Using mouse-adapted prion strains, here we show that highly neuroinvasive prion strains primarily form diffuse aggregates in brain and are noncongophilic, conformationally unstable in denaturing conditions, and lead to rapidly lethal disease. These neuroinvasive strains efficiently generate PrP(Sc) over short incubation periods. In contrast, the weakly neuroinvasive prion strains form large fibrillary plaques and are stable, congophilic, and inefficiently generate PrP(Sc) over long incubation periods. Overall, these results indicate that the most neuroinvasive prion strains are also the least stable, and support the concept that the efficient replication and unstable nature of the most rapidly converting prions may be a feature linked to their efficient spread into the CNS.

Awake craniotomy with brain mapping as the routine surgical approach to treating patients with supratentorial intraaxial tumors: a prospective trial of 200 cases.

OBJECT Awake craniotomy was performed as the standard surgical approach to supratentorial intraaxial tumors, regardless of the involvement of eloquent cortex, in a prospective trial of 200 patients surgically treated by the same surgeon at a single institution. METHODS Patient presentations, comorbid conditions, tumor locations, and the histological characteristics of lesions were recorded. Brain mapping was possible in 195 (97.5%) of 200 patients. The total number of patients sustaining complications was 33 for an overall complication rate of 16.5%. There were two deaths in this series, for a mortality rate of 1%. New postoperative neurological deficits were seen in 13% of the patients, but these were permanent in only 4.5% of them. Complication rates were higher in patients who had gliomas or preoperative neurological deficits and in those who had undergone prior radiation therapy or surgery. No patient who entered the operating room neurologically intact sustained a permanent neurological deficit postoperatively. Of the most recent 50 patients treated, three (6%) required a stay in the intensive care unit, and the median total hospital stay was 1 day. CONCLUSIONS Use of awake craniotomy can result in a considerable reduction in resource utilization without compromising patient care by minimizing intensive care time and total hospital stay. Awake craniotomy is a practical and effective standard surgical approach to supratentorial tumors with a low complication rate, and provides an excellent alternative to craniotomy performed with the patient in the state of general anesthesia because it allows the opportunity for brain mapping and avoids general anesthesia.

Reversal of the cellular phenotype in the premature aging disease Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a childhood premature aging disease caused by a spontaneous point mutation in lamin A (encoded by LMNA), one of the major architectural elements of the mammalian cell nucleus. The HGPS mutation activates an aberrant cryptic splice site in LMNA pre-mRNA, leading to synthesis of a truncated lamin A protein and concomitant reduction in wild-type lamin A. Fibroblasts from individuals with HGPS have severe morphological abnormalities in nuclear envelope structure. Here we show that the cellular disease phenotype is reversible in cells from individuals with HGPS. Introduction of wild-type lamin A protein does not rescue the cellular disease symptoms. The mutant LMNA mRNA and lamin A protein can be efficiently eliminated by correction of the aberrant splicing event using a modified oligonucleotide targeted to the activated cryptic splice site. Upon splicing correction, HGPS fibroblasts assume normal nuclear morphology, the aberrant nuclear distribution and cellular levels of lamina-associated proteins are rescued, defects in heterochromatin-specific histone modifications are corrected and proper expression of several misregulated genes is reestablished. Our results establish proof of principle for the correction of the premature aging phenotype in individuals with HGPS.

Disruption of the immune-checkpoint VISTA gene imparts a proinflammatory phenotype with predisposition to the development of autoimmunity.

V domain-containing Ig suppressor of T-cell activation (VISTA) is a negative checkpoint regulator that suppresses T cell-mediated immune responses. Previous studies using a VISTA-neutralizing monoclonal antibody show that VISTA blockade enhances T-cell activation. The current study describes a comprehensive characterization of mice in which the gene for VISTA has been deleted. Despite the apparent normal hematopoietic development in young mice, VISTA genetic deficiency leads to a gradual accumulation of spontaneously activated T cells, accompanied by the production of a spectrum of inflammatory cytokines and chemokines. Enhanced T-cell responsiveness was also observed upon immunization with neoantigen. Despite the presence of multiorgan chronic inflammation, aged VISTA-deficient mice did not develop systemic or organ-specific autoimmune disease. Interbreeding of the VISTA-deficient mice with 2D2 T-cell receptor transgenic mice, which are predisposed to the development of experimental autoimmune encephalomyelitis, drastically enhanced disease incidence and intensity. Disease development is correlated with the increase in the activation of encephalitogenic T cells in the periphery and enhanced infiltration into the CNS. Taken together, our data suggest that VISTA is a negative checkpoint regulator whose loss of function lowers the threshold for T-cell activation, allowing for an enhanced proinflammatory phenotype and an increase in the frequency and intensity of autoimmunity under susceptible conditions.

Single-Construct Polycistronic Doxycycline-Inducible Vectors Improve Direct Cardiac Reprogramming and Can Be Used to Identify the Critical Timing of Transgene Expression

Direct reprogramming is a promising approach in regenerative medicine. Overexpression of the cardiac transcription factors Gata4, Mef2c, and Tbx5 (GMT) or GMT plus Hand2 (GHMT) directly reprogram fibroblasts into cardiomyocyte-like cells (iCMs). However, the critical timing of transgene expression and the molecular mechanisms for cardiac reprogramming remain unclear. The conventional doxycycline (Dox)-inducible temporal transgene expression systems require simultaneous transduction of two vectors (pLVX-rtTA/pLVX-cDNA) harboring the reverse tetracycline transactivator (rtTA) and the tetracycline response element (TRE)-controlled transgene, respectively, leading to inefficient cardiac reprogramming. Herein, we developed a single-construct-based polycistronic Dox-inducible vector (pDox-cDNA) expressing both the rtTA and TRE-controlled transgenes. Fluorescence activated cell sorting (FACS) analyses, quantitative RT-PCR, and immunostaining revealed that pDox-GMT increased cardiac reprogramming three-fold compared to the conventional pLVX-rtTA/pLVX-GMT. After four weeks, pDox-GMT-induced iCMs expressed multiple cardiac genes, produced sarcomeric structures, and beat spontaneously. Co-transduction of pDox-Hand2 with retroviral pMX-GMT increased cardiac reprogramming three-fold compared to pMX-GMT alone. Temporal Dox administration revealed that Hand2 transgene expression is critical during the first two weeks of cardiac reprogramming. Microarray analyses demonstrated that Hand2 represses cell cycle-promoting genes and enhances cardiac reprogramming. Thus, we have developed an efficient temporal transgene expression system, which could be invaluable in the study of cardiac reprogramming.

Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination.

BACKGROUND The combination of ataxia and hypogonadism was first described more than a century ago, but its genetic basis has remained elusive. METHODS We performed whole-exome sequencing in a patient with ataxia and hypogonadotropic hypogonadism, followed by targeted sequencing of candidate genes in similarly affected patients. Neurologic and reproductive endocrine phenotypes were characterized in detail. The effects of sequence variants and the presence of an epistatic interaction were tested in a zebrafish model. RESULTS Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family. Additional screening identified compound heterozygous truncating mutations in RNF216 in an unrelated patient and single heterozygous deleterious mutations in four other patients. Knockdown of rnf216 or otud4 in zebrafish embryos induced defects in the eye, optic tectum, and cerebellum; combinatorial suppression of both genes exacerbated these phenotypes, which were rescued by nonmutant, but not mutant, human RNF216 or OTUD4 messenger RNA. All patients had progressive ataxia and dementia. Neuronal loss was observed in cerebellar pathways and the hippocampus; surviving hippocampal neurons contained ubiquitin-immunoreactive intranuclear inclusions. Defects were detected at the hypothalamic and pituitary levels of the reproductive endocrine axis. CONCLUSIONS The syndrome of hypogonadotropic hypogonadism, ataxia, and dementia can be caused by inactivating mutations in RNF216 or by the combination of mutations in RNF216 and OTUD4. These findings link disordered ubiquitination to neurodegeneration and reproductive dysfunction and highlight the power of whole-exome sequencing in combination with functional studies to unveil genetic interactions that cause disease. (Funded by the National Institutes of Health and others.).

Surgical Resection for Patients with Solid Brain Metastases: Current Status

Brain metastases occur in up to 40% of patients with cancer. Their management has been revolutionized in the last decade by three developments: improved imaging and detection of metastases, better treatment of systemic disease with the result that metastases occur more often; and improved surgical techniques including image-guided surgery to treat metastatic lesions. Class 1 data suggest that surgery is a better treatment for metastases than whole brain radiation. Other data suggest that metastases even in eloquent cortex can be removed safely. The complication rate is low and the recurrence rate is less than 10%. In general, indications for surgery include a mass with an unknown primary; a symptomatic mass including one in eloquent areas; a mass with considerable edema requiring high dose steroids; a mass greater than 3 cm; or patient preference when radiosurgery may also be an option. The question of radiosurgery or whole brain radiation as adjunct to surgical removal requires further evaluation.

Cryo-EM structures of Tau filaments from Alzheimer’s disease brain

Alzheimer's disease is the most common neurodegenerative disease, and there are no mechanism-based therapies. The disease is defined by the presence of abundant neurofibrillary lesions and neuritic plaques in the cerebral cortex. Neurofibrillary lesions comprise paired helical and straight tau filaments, whereas tau filaments with different morphologies characterize other neurodegenerative diseases. No high-resolution structures of tau filaments are available. Here we present cryo-electron microscopy (cryo-EM) maps at 3.4-3.5 Å resolution and corresponding atomic models of paired helical and straight filaments from the brain of an individual with Alzheimer's disease. Filament cores are made of two identical protofilaments comprising residues 306-378 of tau protein, which adopt a combined cross-β/β-helix structure and define the seed for tau aggregation. Paired helical and straight filaments differ in their inter-protofilament packing, showing that they are ultrastructural polymorphs. These findings demonstrate that cryo-EM allows atomic characterization of amyloid filaments from patient-derived material, and pave the way for investigation of a range of neurodegenerative diseases.

Asymptomatic spinal cord lesions predict disease progression in radiologically isolated syndrome.

BACKGROUND Technological advancements in neuroimaging and the increased use of these diagnostic modalities are responsible for the discovery of incidentally identified anomalies within the CNS. In addition to the identification of unanticipated brain MRI abnormalities suggestive of demyelinating disease in patients undergoing neuroimaging for a medical reason other than evaluation for multiple sclerosis (MS), asymptomatic spinal cord lesions are periodically identified. OBJECTIVE To determine if asymptomatic spinal cord lesions are associated with clinical progression in subjects with radiologically isolated syndrome (RIS). METHODS A retrospective review of RIS cases at the University of California, San Francisco Multiple Sclerosis Center was performed. The presence of asymptomatic cervical spinal cord MRI lesions was analyzed as a potential predictor for clinical progression. RESULTS Twenty-five of 71 subjects with RIS possessed findings within the cervical spine that were highly suggestive of demyelinating disease. Of these subjects, 21 (84%) progressed clinically to clinically isolated syndrome (n = 19) or primary progressive multiple sclerosis (n = 2) over a median time of 1.6 years from the date of RIS identification (interquartile range 0.8-3.8). The sensitivity, specificity, and positive predictive value of an asymptomatic spinal cord lesion for subsequent development of either a first demyelinating attack or primary progressive MS were 87.5%, 91.5%, and 84%, respectively. The odds ratio of clinical progression was 75.3 (95% confidence interval 16.1-350.0, p < 0.0001). This association remained significant after adjusting for potential confounders. CONCLUSION These findings suggest that the presence of asymptomatic spinal cord lesions place subjects with RIS at substantial risk for clinical conversion to either an acute or progressive event, a risk that is independent of brain lesions on MRI.

Embryonic Stem Cells for Severe Heart Failure: Why and How?

The experience accumulated in cardiac cell therapy suggests that regeneration of extensively necrotic myocardial areas is unlikely to be achieved by the sole paracrine effects of the grafted cells but rather requires the conversion of these cells into cardiomyocytes featuring the capacity to substitute for those which have been irreversibly lost. In this setting, the use of human pluripotent embryonic stem cells has a strong rationale. The experimental results obtained in animal models of myocardial infarction are encouraging. However, the switch to clinical applications still requires to address some critical issues, among which the optimization of the cardiac specification of the embryonic stem cells, the purification of the resulting progenitor cells so as to graft a purified population devoid from any contamination by residual pluripotent cells which carry the risk of tumorigenesis, and the control of the expected allogeneic rejection by clinically acceptable methods. If the solution to these problems is a prerequisite, the therapeutic success of this approach will also depend on the capacity to efficiently transfer the cells to the target tissue, to keep them alive once engrafted, and to allow them to spatially organize in such a way that they can contribute to the contractile function of the heart.

Myogenic and morphogenetic defects in the heart tubes of murine embryos lacking the homeo box gene Nkx2-5.

The murine homeo box gene Nkx2-5 is expressed in precardiac mesoderm and in the myocardium of embryonic and fetal hearts. Targeted interruption of Nkx2-5 resulted in abnormal heart morphogenesis, growth retardation and embryonic lethality at approximately 9-10 days postcoitum (p.c.). Heart tube formation occurred normally in mutant embryos, but looping morphogenesis, a critical determinant of heart form, was not initiated at the linear heart tube stage (8.25-8.5 days p.c.). Commitment to the cardiac muscle lineage, expression of most myofilament genes and myofibrillogenesis were not compromised. However, the myosin light-chain 2V gene (MLC2V) was not expressed in mutant hearts nor in mutant ES cell-derived cardiocytes. MLC2V expression normally occurs only in ventricular cells and is the earliest known molecular marker of ventricular differentiation. The regional expression in mutant hearts of two other ventricular markers, myosin heavy-chain beta and cyclin D2, indicated that not all ventricle-specific gene expression is dependent on Nkx2-5. The data demonstrate that Nkx2-5 is essential for normal heart morphogenesis, myogenesis, and function. Furthermore, this gene is a component of a genetic pathway required for myogenic specialization of the ventricles.

Direct conversion of patient fibroblasts demonstrates non-cell autonomous toxicity of astrocytes to motor neurons in familial and sporadic ALS.

Amyotrophic lateral sclerosis (ALS) causes motor neuron degeneration, paralysis, and death. Accurate disease modeling, identifying disease mechanisms, and developing therapeutics is urgently needed. We previously reported motor neuron toxicity through postmortem ALS spinal cord-derived astrocytes. However, these cells can only be harvested after death, and their expansion is limited. We now report a rapid, highly reproducible method to convert adult human fibroblasts from living ALS patients to induced neuronal progenitor cells and subsequent differentiation into astrocytes (i-astrocytes). Non-cell autonomous toxicity to motor neurons is found following coculture of i-astrocytes from familial ALS patients with mutation in superoxide dismutase or hexanucleotide expansion in C9orf72 (ORF 72 on chromosome 9) the two most frequent causes of ALS. Remarkably, i-astrocytes from sporadic ALS patients are as toxic as those with causative mutations, suggesting a common mechanism. Easy production and expansion of i-astrocytes now enables rapid disease modeling and high-throughput drug screening to alleviate astrocyte-derived toxicity.

Lessons from sudden coronary death: a comprehensive morphological classification scheme for atherosclerotic lesions.

This review will reconsider the current paradigm for understanding the critical, final steps in the progression of atherosclerotic lesions. That scheme, largely an outgrowth of observations of autopsy tissues by Davies and colleagues,1 2 asserts that the cause of death in atherosclerotic coronary artery disease is rupture of an advanced atherosclerotic lesion. Although this assumption may be partially true, recent autopsy studies suggest that it is incomplete. To reconsider this paradigm, we reexamined the morphological classification scheme for lesions proposed by the American Heart Association (AHA).3 4 This scheme is difficult to use for 2 reasons. First, it uses a very long list of roman numerals modified by letter codes that are difficult to remember. Second, it implies an orderly, linear pattern of lesion progression. This tends to be ambiguous, because it is not clear whether there is a single sequence of events during the progression of all lesions. We have therefore tried to devise a simpler classification scheme that is consistent with the AHA categories but is easier to use, able to deal with a wide array of morphological variations, and not overly burdened by mechanistic implications. The current paradigm is based on the belief that type IV lesions, or “atheromas,” described by the AHA are stable because the fatty, necrotic core is contained by a smooth muscle cell–rich fibrous cap. Virchow’s analysis5 in 1858 pointed out that historically, the term “atheroma” refers to a dermal cyst (“Grutzbalg”), a fatty …

Small molecules enable cardiac reprogramming of mouse fibroblasts with a single factor, Oct4.

It was recently shown that mouse fibroblasts could be reprogrammed into cells of a cardiac fate by forced expression of multiple transcription factors and microRNAs. For ultimate application of such a reprogramming strategy for cell-based therapy or in vivo cardiac regeneration, reducing or eliminating the genetic manipulations by small molecules would be highly desirable. Here, we report the identification of a defined small-molecule cocktail that enables the highly efficient conversion of mouse fibroblasts into cardiac cells with only one transcription factor, Oct4, without any evidence of entrance into the pluripotent state. Small-molecule-induced cardiomyocytes spontaneously contract and exhibit a ventricular phenotype. Furthermore, these induced cardiomyocytes pass through a cardiac progenitor stage. This study lays the foundation for future pharmacological reprogramming approaches and provides a small-molecule condition for investigation of the mechanisms underlying the cardiac reprogramming process.

Atherosclerotic plaque rupture--pathologic basis of plaque stability and instability.

Time for primary reveiw 27 days   Atherosclerosis continues to be one of the main subjects in pathology research. The intriguing complexity of its pathogenesis as well as the importance of its clinical sequelae provide a rationale for this [1]. A large number of diseases with totally different clinical presentations are basically atherosclerosis related, and among these, myocardial infarction, stroke, abdominal aneurysms and lower limb ischemia determine to a large extent the morbidity and mortality in Western style populations. But, despite this broad spectrum of clinical disease, most of the acute manifestations of atherosclerosis share a common pathogenetic feature: rupture of an atherosclerotic plaque [2–4]. Plaque disruptions may vary greatly in extent from tiny fissures or erosions of the plaque surface to deep intimal tears which extend into the soft lipid core of lesions; in all these instances, at least some degree of thrombus formation occurs [5, 6]. The abdominal aorta is the arterial site most prominently involved in the process of plaque formation, and also of plaque complications. In this large diameter vessel the process of plaque disruption and thrombosis is not ended by luminal occlusion, and may lead to extensive surface ulcerations comprising large areas of the aortic wall, as can be observed in many autopsy cases at older age. Apart from the undisputable role of atherosclerosis in abdominal aneurysm formation [7], mural thrombosis leads to a surprisingly low rate of clinically significant complications in these patients, although cholesterol emboli can be regularly found in their kidneys and skin at autopsy. Still, it is presently unclear what impact the various biologically active mediators released from eroded aortic surfaces may have on the human body. In contrast, in small diameter vessels such as coronary arteries, occlusive thrombosis is a frequent and often fatal complication of plaque …   * Corresponding author. Tel.: +31-20-5665-633; fax: +31-20-914-738; e-mail a.c.vanderwal@amc.uva.nl

Locations of cerebral infarctions in tuberculous meningitis

The locations of cerebral infarctions were studied in 14 patients with tuberculous meningitis (TBM) and 173 patients with noninflammatory ischemic stroke (IS). In patients with TBM, 75% of infarctions occurred in the “TB zone” supplied by medial striate and thalamoperforating arteries; only 11% occurred in the “IS zone” supplied by lateral striate, anterior choroidal and thalamogeniculate arteries. In patients with IS 29% of infarctions occurred in the IS zone, 29% in the subcortical white matter, and 24% in (or involving) the cerebral cortex. Only 11% occurred in the TB zone. Bilaterally symmetrical infarctions of the TB zone were common with TMB (71%) but rare with IS (5%).

Vanishing cerebellar infarcts in a migraine patient.

Recent population-based studies have suggested that migraine is a risk factor for the development of infarct-like lesions in the territory of the posterior circulation. These lesions are thought to be true vascular infarcts based on their size, location and magnetic resonance imaging (MRI) characteristics. However, as there are no postmortem studies identifying the pathology of these MRI findings, their true aetiology is unknown. A case patient with migraine is presented, who developed what appeared to be cerebellar infarcts on MRI, but these lesions vanished on repeat imaging 16 days later, questioning their aetiology as vascular ischaemic based infarcts.

Local neuroinflammation and the progression of Alzheimer’s disease

Postmortem immunohistochemical studies have revealed a state of chronic inflammation limited to lesioned areas of brain in Alzheimer’s disease. Some key actors in this inflammation are activated microglia (brain macrophages), proteins of the classical complement cascade, the pentraxins, cytokines, and chemokines. The inflammation does not involve the adaptive immune system or peripheral organs, but is rather due to the phylogenetically much older innate immune system, which appears to operate in most tissues of the body. Chronic inflammation can damage host tissue and the brain may be particularly vulnerable because of the postmitotic nature of neurons. Many of the inflammatory mediators have been shown to be locally produced and selectively elevated in affected regions of Alzheimer’s brain. Moreover, studies of tissue in such degenerative processes as atherosclerosis and infarcted heart suggest a similar local innate immune reaction may be important in such conditions. Much epidemiological and limited clinical evidence suggests that nonsteroidal anti-inflammatory drugs may impede the onset and slow the progression of Alzheimer’s disease. But these drugs strike at the periphery of the inflammatory reaction. Much better results might be obtained if drugs were found that could inhibit the activation of microglia or the complement system in brain, and combinations of drugs aimed at different inflammatory targets might be much more effective than single agents.

Surgical therapy for dystonia.

Surgical treatments for dystonia have been available since the early 20th century, but have improved in their efficacy to adversity ratio through a combination of technologic advances and better understanding of the role of the basal ganglia in dystonia. The word "dystonia" describes a phenotype of involuntary movement that may manifest from a variety of conditions. Dystonia may affect only certain regions of the body or may be generalized. It appears to be critical to determine whether the etiology underlying the dystonia is "primary" (ie, occurring from a genetic or idiopathic origin) or "secondary" (ie, occurring as a result of structural, metabolic, or neurodegenerative disorders). Secondary dystonias are far more common than primary dystonias. Primary dystonias respond well to pallidotomy or deep brain stimulation of the internal segment of the globus pallidum, whereas secondary dystonias appear to respond partially at best. Limited historic and current data suggest that the thalamus may be a promising target for the treatment of secondary dystonias, but more careful, prospective, randomized studies are needed. Combinations of bilateral targets are possible with the current technology of DBS, but not widely used due to surgical morbidity and expense. This article reviews the surgical treatment of dystonia from past to present, with a focus on separating the outcomes for primary versus secondary and generalized versus cervical dystonia.

A missense LAMB2 mutation causes congenital nephrotic syndrome by impairing laminin secretion.

Laminin β2 is a component of laminin-521, which is an important constituent of the glomerular basement membrane (GBM). Null mutations in laminin β2 (LAMB2) cause Pierson syndrome, a severe congenital nephrotic syndrome with ocular and neurologic defects. In contrast, patients with LAMB2 missense mutations, such as R246Q, can have less severe extrarenal defects but still exhibit congenital nephrotic syndrome. To investigate how such missense mutations in LAMB2 cause proteinuria, we generated three transgenic lines of mice in which R246Q-mutant rat laminin β2 replaced the wild-type mouse laminin β2 in the GBM. These transgenic mice developed much less severe proteinuria than their nontransgenic Lamb2-deficient littermates; the level of proteinuria correlated inversely with R246Q-LAMB2 expression. At the onset of proteinuria, expression and localization of proteins associated with the slit diaphragm and foot processes were normal, and there were no obvious ultrastructural abnormalities. Low transgene expressors developed heavy proteinuria, foot process effacement, GBM thickening, and renal failure by 3 months, but high expressors developed only mild proteinuria by 9 months. In vitro studies demonstrated that the R246Q mutation results in impaired secretion of laminin. Taken together, these results suggest that the R246Q mutation causes nephrotic syndrome by impairing secretion of laminin-521 from podocytes into the GBM; however, increased expression of the mutant protein is able to overcome this secretion defect and improve glomerular permselectivity.

Schedule-dependent interaction between anticancer treatments

The oncogene MDMX is overexpressed in many cancers, leading to suppression of the tumor suppressor p53. Inhibitors of the oncogene product MDMX therefore might help reactivate p53 and enhance the efficacy of DNA-damaging drugs. However, we currently lack a quantitative understanding of how MDMX inhibition affects the p53 signaling pathway and cell sensitivity to DNA damage. Live cell imaging showed that MDMX depletion triggered two distinct phases of p53 accumulation in single cells: an initial postmitotic pulse, followed by low-amplitude oscillations. The response to DNA damage was sharply different in these two phases; in the first phase, MDMX depletion was synergistic with DNA damage in causing cell death, whereas in the second phase, depletion of MDMX inhibited cell death. Thus a quantitative understanding of signal dynamics and cellular states is important for designing an optimal schedule of dual-drug administration.

CNS repair requires both effector and regulatory T cells with distinct temporal and spatial profiles.

Monocyte-derived macrophages (mo-MΦs) and T cells have been shown to contribute to spinal cord repair. Recently, the remote brain choroid plexus epithelium (CP) was identified as a portal for monocyte recruitment, and its activation for leukocyte trafficking was found to be IFN-γ-dependent. Here, we addressed how the need for effector T cells can be reconciled with the role of inflammation-resolving immune cells in the repair process. Using an acute spinal cord injury model, we show that in mice deficient in IFN-γ-producing T cells, the CP was not activated, and recruitment of inflammation-resolving mo-MΦ to the spinal cord parenchyma was limited. We further demonstrate that mo-MΦ locally regulated recruitment of thymic-derived Foxp3(+) regulatory T (Treg) cells to the injured spinal cord parenchyma at the subacute/chronic phase. Importantly, an ablation protocol that resulted in reduced Tregs at this stage interfered with tissue remodeling, in contrast to Treg transient ablation, restricted to the 4 d period before the injury, which favored repair. The enhanced functional recovery observed following such a controlled decrease of Tregs suggests that reduced systemic immunosuppression at the time of the insult can enhance CNS repair. Overall, our data highlight a dynamic immune cell network needed for repair, acting in discrete compartments and stages, and involving effector and regulatory T cells, interconnected by mo-MΦ. Any of these populations may be detrimental to the repair process if their level or activity become dysregulated. Accordingly, therapeutic interventions must be both temporally and spatially controlled.

Protective effects of exercise and phosphoinositide 3-kinase(p110alpha) signaling in dilated and hypertrophic cardiomyopathy.

Physical activity protects against cardiovascular disease, and physiological cardiac hypertrophy associated with regular exercise is usually beneficial, in marked contrast to pathological hypertrophy associated with disease. The p110alpha isoform of phosphoinositide 3-kinase (PI3K) plays a critical role in the induction of exercise-induced hypertrophy. Whether it or other genes activated in the athlete's heart might have an impact on cardiac function and survival in a setting of heart failure is unknown. To examine whether progressive exercise training and PI3K(p110alpha) activity affect survival and/or cardiac function in two models of heart disease, we subjected a transgenic mouse model of dilated cardiomyopathy (DCM) to swim training, genetically crossed cardiac-specific transgenic mice with increased or decreased PI3K(p110alpha) activity to the DCM model, and subjected PI3K(p110alpha) transgenics to acute pressure overload (ascending aortic constriction). Life-span, cardiac function, and molecular markers of pathological hypertrophy were examined. Exercise training and increased cardiac PI3K(p110alpha) activity prolonged survival in the DCM model by 15-20%. In contrast, reduced PI3K(p110alpha) activity drastically shortened lifespan by approximately 50%. Increased PI3K(p110alpha) activity had a favorable effect on cardiac function and fibrosis in the pressure-overload model and attenuated pathological growth. PI3K(p110alpha) signaling negatively regulated G protein-coupled receptor stimulated extracellular responsive kinase and Akt (via PI3K, p110gamma) activation in isolated cardiomyocytes. These findings suggest that exercise and enhanced PI3K(p110alpha) activity delay or prevent progression of heart disease, and that supraphysiologic activity can be beneficial. Identification of genes important for hypertrophy in the athlete's heart could offer new strategies for treating heart failure.

Progression of preclinical diastolic dysfunction to the development of symptoms.

BACKGROUND Preclinical diastolic dysfunction (PDD) has been defined as subjects with normal systolic function, diastolic dysfunction but no symptoms of heart failure (HF). The clinical phenotype and natural history of the syndrome remains poorly defined. This study's objective was to determine the clinical phenotype and progression to HF in a group of patients with normal systolic function and moderate or severe diastolic dysfunction as determinate by Doppler criteria without any clinical diagnosis of HF according to the Framingham criteria or any symptoms of HF, specifically dyspnoea, oedema or fatigue at the time of echocardiography. METHODS The authors used resources of the Mayo Clinic echocardiography database to consecutively select among patients who had an echocardiogram in 2005, a cohort with moderate or severe diastolic dysfunction by Doppler criteria and EF >or=50%. Patients could not have a diagnosis of HF, or any HF symptoms-specifically dyspnoea, oedema or fatigue-at the time of echocardiography; nor grade 3 or greater valvular dysfunction (except tricuspid valve). A total of 82 patients had their medical chart reviewed. Primary endpoint was the time to the development of (1) HF according to the Framingham criteria or (2) any symptoms of dyspnoea, oedema or fatigue. RESULTS The mean age of the cohort of PDD subjects was 69+/-10 years with a female (67%) preponderance. Presence of hypertension was 76%, coronary artery disease was 29%, paroxysmal atrial fibrillation was 26%, estimated creatinine clearance <60 ml/min was 51%. The 2-year cumulative probability of development of HF according to the Framingham criteria was 1.9%; however, the 2-year cumulative probability of development of any symptoms was 31.1%. The 2-year cumulative probability for cardiac hospitalisation was 21.2%. Peripheral vascular disease and hypertension were independently associated with increased likelihood for the development of symptoms. CONCLUSION The study demonstrates that hypertension, hyperlipidaemia, CAD and renal dysfunction are prevalent in patients with PDD. More importantly, although the progression to the development of clinical HF over 2 years was low, there was a moderate degree of progression to development of symptoms and cardiac hospitalisations over 2 years. Based on the finding that only PVD and hypertension were independently associated with the progression to the development of symptoms in subject with PDD, the authors speculate that ventricular-arterial interaction may be important to the progression of diastolic dysfunction to the development of symptoms.

MG53 nucleates assembly of cell membrane repair machinery

Dynamic membrane repair and remodelling is an elemental process that maintains cell integrity and mediates efficient cellular function. Here we report that MG53, a muscle-specific tripartite motif family protein (TRIM72), is a component of the sarcolemmal membrane-repair machinery. MG53 interacts with phosphatidylserine to associate with intracellular vesicles that traffic to and fuse with sarcolemmal membranes. Mice null for MG53 show progressive myopathy and reduced exercise capability, associated with defective membrane-repair capacity. Injury of the sarcolemmal membrane leads to entry of the extracellular oxidative environment and MG53 oligomerization, resulting in recruitment of MG53-containing vesicles to the injury site. After vesicle translocation, entry of extracellular Ca2+ facilitates vesicle fusion to reseal the membrane. Our data indicate that intracellular vesicle translocation and Ca2+-dependent membrane fusion are distinct steps involved in the repair of membrane damage and that MG53 may initiate the assembly of the membrane repair machinery in an oxidation-dependent manner.

Stages of the pathologic process in Alzheimer disease: age categories from 1 to 100 years.

Two thousand three hundred and thirty two nonselected brains from 1- to 100-year-old individuals were examined using immunocytochemistry (AT8) and Gallyas silver staining for abnormal tau; immunocytochemistry (4G8) and Campbell-Switzer staining were used for the detection ofβ-amyloid. A total of 342 cases was negative in the Gallyas stain but when restaged for AT8 only 10 were immunonegative. Fifty-eight cases had subcortical tau predominantly in the locus coeruleus, but there was no abnormal cortical tau (subcortical Stages a-c). Cortical involvement (abnormal tau in neurites) was identified first in the transentorhinal region (Stage 1a, 38 cases). Transentorhinal pyramidal cells displayed pretangle material (Stage 1b, 236 cases). Pretangles gradually became argyrophilic neurofibrillary tangles (NFTs) that progressed in parallel with NFT Stages I to VI. Pretangles restricted to subcortical sites were seen chiefly at younger ages. Of the total cases, 1,031 (44.2%) had β-amyloid plaques. The first plaques occurred in the neocortex after the onset of tauopathy in the brainstem. Plaques generally developed in the 40s in 4% of all cases, culminating in their tenth decade (75%). β-amyloid plaques and NFTs were significantly correlated (p < 0.0001). These data suggest that tauopathy associated with sporadic Alzheimer disease may begin earlier than previously thought and possibly in the lower brainstem rather than in the transentorhinal region.

Order of intron removal influences multiple splice outcomes, including a two-exon skip, in a COL5A1 acceptor-site mutation that results in abnormal pro-alpha1(V) N-propeptides and Ehlers-Danlos syndrome type I.

Ehlers-Danlos syndrome (EDS) type I (the classical variety) is a dominantly inherited, genetically heterogeneous connective-tissue disorder. Mutations in the COL5A1 and COL5A2 genes, which encode type V collagen, have been identified in several individuals. Most mutations affect either the triple-helical domain of the protein or the expression of one COL5A1 allele. We identified a novel splice-acceptor mutation (IVS4-2A-->G) in the N-propeptide-encoding region of COL5A1, in one patient with EDS type I. The outcome of this mutation was complex: In the major product, both exons 5 and 6 were skipped; other products included a small amount in which only exon 5 was skipped and an even smaller amount in which cryptic acceptor sites within exon 5 were used. All products were in frame. Pro-alpha1(V) chains with abnormal N-propeptides were secreted and were incorporated into extracellular matrix, and the mutation resulted in dramatic alterations in collagen fibril structure. The two-exon skip occurred in transcripts in which intron 5 was removed rapidly relative to introns 4 and 6, leaving a large (270 nt) composite exon that can be skipped in its entirety. The transcripts in which only exon 5 was skipped were derived from those in which intron 6 was removed prior to intron 5. The use of cryptic acceptor sites in exon 5 occurred in transcripts in which intron 4 was removed subsequent to introns 5 and 6. These findings suggest that the order of intron removal plays an important role in the outcome of splice-site mutations and provide a model that explains why multiple products derive from a mutation at a single splice site.

Targeting of cell-surface β-amyloid precursor protein to lysosomes: alternative processing into amyloid-bearing fragments

PROGRESSIVE cerebral deposition of the amyloid β-peptide is an early and invariant feature of Alzheimer's disease. The β-peptide is released by proteolytic cleavages from the β-amyloid precursor protein (βAPP)1, a membrane-spanning glycoprotein expressed in most mammalian cells. Normal secretion of βAPP involves a cleavage in the β-peptide region2-3, releasing the soluble extramembranous portion4,5 and retaining a 10K C-terminal fragment in the membrane6. Because this secretory pathway precludes β-amyloid formation, we searched for an alternative proteolytic processing pathway that can generate β-peptide-bearing fragments from full-length β APP. Incubation of living human endothelial cells with a βAPP antibody revealed reinternalization of mature βAPP from the cell surface and its targeting to endosomes/lysosomes. After cell-surface biotinylation, full-length biotinylated βAPP was recovered inside the cells. Purification of lysosomes directly demonstrated the presence of mature βAPP and an extensive array of β-peptide-containing proteolytic products. Our results define a second processing pathway for βAPP and suggest that it may be responsible for generating amyloid-bearing fragments in Alzheimer's disease.

Angiogenesis therapy: amidst the hype, the neglected potential for serious side effects.

Although essentially unknown as a therapeutic concept as recently as a decade ago, it is difficult now to open a cardiology journal, attend a cardiology meeting, or scan a newspaper without being caught up in the excitement generated by the thought that angiogenesis therapy may soon have a major impact on the treatment of patients with atherosclerotic lesions obstructing arteries that supply the myocardium or legs. Potent therapeutic interventions, however, are rarely free of at least the potential for causing harmful effects. Angiogenesis therapy is no exception. Despite this and despite the fact that the only reasonably powered, randomized, double-blind clinical studies to date have failed to demonstrate primary end-point efficacy,1 thoughtful consideration of the serious side effects that might accompany any therapeutic benefit has been largely missing from scientific communications. For the lay media, a switch from this unbounded enthusiasm to profound skepticism occurred recently after a report of the tragic death of a young man caused by injection of large amounts of an adenoviral vector into the hepatic artery (unrelated to angiogenesis therapy).2 For the scientific community, however, there has been a general lack of in-depth discussion of the potential dangers inherent in angiogenesis interventions. Such a discussion is appropriate not only because of the event cited above but also because considerable mechanistic data are available that actually permit us to identify specific side effects that we might anticipate as potential complications of angiogenesis therapy. The following therefore is a discussion of potential complications based predominantly on our knowledge of the underlying biological activities of 2 of the most potent angiogenic cytokines, vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). Angiogenic agents are thought to have the potential to induce neovascularization in many different tissues. This becomes important in that under clinical circumstances it …

Coronary plaque disruption.

Coronary atherosclerosis is by far the most frequent cause of ischemic heart disease, and plaque disruption with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death.1 2 3 4 5 Therefore, for event-free survival, the vital question is not why atherosclerosis develops but rather why, after years of indolent growth, it suddenly becomes complicated by life-threatening thrombosis. The composition and vulnerability of plaque rather than its volume or the consequent severity of stenosis produced have emerged as being the most important determinants for the development of the thrombus-mediated acute coronary syndromes; lipid-rich and soft plaques are more dangerous than collagen-rich and hard plaques because they are more unstable and rupture-prone and highly thrombogenic after disruption.6 This review will explore potential mechanisms responsible for the sudden conversion of a stable atherosclerotic plaque to an unstable and life-threatening atherothrombotic lesion—an event known as plaque fissuring, rupture, or disruption.7 8   Atherosclerosis is the result of a complex interaction between blood elements, disturbed flow, and vessel wall abnormality, involving several pathological processes: inflammation, with increased endothelial permeability, endothelial activation, and monocyte recruitment9 10 11 12 13 14 ; growth, with smooth muscle cell (SMC) proliferation, migration, and matrix synthesis15 16 ; degeneration, with lipid accumulation17 18 ; necrosis, possibly related to the cytotoxic effect of oxidized lipid19 ; calcification/ossification, which may represent an active rather than a dystrophic process20 21 ; and thrombosis, with platelet recruitment and fibrin formation.1 22 23 Thrombotic factors may play a role early during atherogenesis, but a flow-limiting thrombus does not develop until mature plaques are present, which is why thrombosis often is classified as a complication rather than a genuine component of atherosclerosis. ### Mature Plaques: Atherosis and Sclerosis   As the name atherosclerosis implies, mature …

Astrocytes from Familial and Sporadic ALS Patients are Toxic to Motor Neurons

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease, with astrocytes implicated as contributing substantially to motor neuron death in familial (F)ALS. However, the proposed role of astrocytes in the pathology of ALS derives in part from rodent models of FALS based upon dominant mutations within the superoxide dismutase 1 (SOD1) gene, which account for <2% of all ALS cases. Their role in sporadic (S)ALS, which affects >90% of ALS patients, remains to be established. Using astrocytes generated from postmortem tissue from both FALS and SALS patients, we show that astrocytes derived from both patient groups are similarly toxic to motor neurons. We also demonstrate that SOD1 is a viable target for SALS, as its knockdown significantly attenuates astrocyte-mediated toxicity toward motor neurons. Our data highlight astrocytes as a non-cell autonomous component in SALS and provide an in vitro model system to investigate common disease mechanisms and evaluate potential therapies for SALS and FALS.

Multicenter phase II study of lapatinib in patients with brain metastases from HER2-positive breast cancer.

PURPOSE Brain metastases develop in one third of patients with advanced HER2+ breast cancer. Effective therapy for patients with central nervous system (CNS) progression after cranial radiation is extremely limited and represents a major clinical challenge. Lapatinib, an epidermal growth factor receptor/HER2 inhibitor, was associated with regressions of CNS lesions in a small phase 2 trial. The current study was done to further evaluate the CNS activity of lapatinib. The study was later amended to allow patients who progressed on lapatinib the option of receiving lapatinib plus capecitabine. EXPERIMENTAL DESIGN Eligible patients had HER2+ breast cancer, progressive brain metastases, prior trastuzumab, and cranial radiotherapy. The primary end point was CNS objective response, defined as >or=50% volumetric reduction of CNS lesion(s) in the absence of increasing steroid use, progressive neurologic signs and symptoms, or progressive extra-CNS disease. RESULTS Two-hundred and forty-two patients entered the study. CNS objective responses to lapatinib were observed in 6% of patients. In an exploratory analysis, 21% of patients experienced a >or=20% volumetric reduction in their CNS lesions. An association was observed between volumetric reduction and improvement in progression-free survival and neurologic signs and symptoms. Of the 50 evaluable patients who entered the lapatinib plus capecitabine extension, 20% experienced a CNS objective response and 40% experienced a >or=20% volumetric reduction in their CNS lesions. CONCLUSIONS This study confirms the modest CNS antitumor activity of lapatinib. Additional responses were observed with the combination of lapatinib and capecitabine. Further studies of lapatinib-based regimens for CNS metastases from HER2+ breast cancer are warranted.

Nephrin mutations cause childhood- and adult-onset focal segmental glomerulosclerosis.

Mutations in the NPHS1 gene cause congenital nephrotic syndrome of the Finnish type presenting before the first 3 months of life. Recently, NPHS1 mutations have also been identified in childhood-onset steroid-resistant nephrotic syndrome and milder courses of disease, but their role in adults with focal segmental glomerulosclerosis remains unknown. Here we developed an in silico scoring matrix to evaluate the pathogenicity of amino-acid substitutions using the biophysical and biochemical difference between wild-type and mutant amino acid, the evolutionary conservation of the amino-acid residue in orthologs, and defined domains, with the addition of contextual information. Mutation analysis was performed in 97 patients from 89 unrelated families, of which 52 presented with steroid-resistant nephrotic syndrome after 18 years of age. Compound heterozygous or homozygous NPHS1 mutations were identified in five familial and seven sporadic cases, including one patient 27 years old at onset of the disease. Substitutions were classified as 'severe' or 'mild' using this in silico approach. Our results suggest an earlier onset of the disease in patients with two 'severe' mutations compared to patients with at least one 'mild' mutation. The finding of mutations in a patient with adult-onset focal segmental glomerulosclerosis indicates that NPHS1 analysis could be considered in patients with later onset of the disease.

Neuronal replacement from endogenous precursors in the adult brain after stroke

In the adult brain, new neurons are continuously generated in the subventricular zone and dentate gyrus, but it is unknown whether these neurons can replace those lost following damage or disease. Here we show that stroke, caused by transient middle cerebral artery occlusion in adult rats, leads to a marked increase of cell proliferation in the subventricular zone. Stroke-generated new neurons, as well as neuroblasts probably already formed before the insult, migrate into the severely damaged area of the striatum, where they express markers of developing and mature, striatal medium-sized spiny neurons. Thus, stroke induces differentiation of new neurons into the phenotype of most of the neurons destroyed by the ischemic lesion. Here we show that the adult brain has the capacity for self-repair after insults causing extensive neuronal death. If the new neurons are functional and their formation can be stimulated, a novel therapeutic strategy might be developed for stroke in humans.

The DNA damage response during mitosis.

Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed.

Recommended diagnostic criteria for multiple sclerosis: guidelines from the International Panel on the diagnosis of multiple sclerosis.

The International Panel on MS Diagnosis presents revised diagnostic criteria for multiple sclerosis (MS). The focus remains on the objective demonstration of dissemination of lesions in both time and space. Magnetic resonance imaging is integrated with dinical and other paraclinical diagnostic methods. The revised criteria facilitate the diagnosis of MS in patients with a variety of presentations, including "monosymptomatic" disease suggestive of MS, disease with a typical relapsing-remitting course, and disease with insidious progression, without clear attacks and remissions. Previously used terms such as "clinically definite" and "probable MS" are no longer recommended. The outcome of a diagnostic evaluation is either MS, "possible MS" (for those at risk for MS, but for whom diagnostic evaluation is equivocal), or "not MS. "

Neurological outcomes of animal models of uterine artery ligation and relevance to human intrauterine growth restriction: a systematic review

AIM This review explores the molecular, neurological, and behavioural outcomes in animal models of uterine artery ligation. We analyse the relevance of this type of model to the pathological and functional phenotypes that are consistent with cerebral palsy and its developmental comorbidities in humans. METHOD A literature search of the PubMed database was conducted for research using the uterine artery ligation model published between 1990 and 2013. From the studies included, any relevant neuroanatomical and behavioural deficits were then summarized from each document and used for further analysis. RESULTS There were 25 papers that met the criteria included for review, and several outcomes were summarized from the results of these papers. Fetuses with growth restriction demonstrated a gradient of reduced body weight with a relative sparing of brain mass. There was a significant reduction in the size of the somatosensory cortex, hippocampus, and corpus callosum. The motor cortex appeared to be spared of identifiable deficits. Apoptotic proteins were upregulated, while those important to neuronal survival, growth, and differentiation were downregulated. Neuronal apoptosis and astrogliosis occurred diffusely throughout the brain regions. White matter injury involved oligodendrocyte precursor maturation arrest, hypomyelination, and an aberrant organization of existing myelin. Animals with growth restriction demonstrated deficits in gait, memory, object recognition, and spatial processing. INTERPRETATION This review concludes that neuronal death, white matter injury, motor abnormalities, and cognitive deficits are important outcomes of uterine artery ligation in animal models. Therefore, this is a clinically relevant type of model, as these findings resemble deficits in human cerebral palsy.

Enzymatically active lysosomal proteases are associated with amyloid deposits in Alzheimer brain.

The formation of beta-amyloid in the brains of individuals with Alzheimer disease requires the proteolytic cleavage of a membrane-associated precursor protein. The proteases that may be involved in this process have not yet been identified. Cathepsins are normally intracellular proteolytic enzymes associated with lysosomes; however, when sections from Alzheimer brains were stained by antisera to cathepsin D and cathepsin B, high levels of immunoreactivity were also detected in senile plaques. Extracellular sites of cathepsin immunoreactivity were not seen in control brains from age-matched individuals without neurologic disease or from patients with Huntington disease or Parkinson disease. In situ enzyme histochemistry of cathepsin D and cathepsin B on sections of neocortex using synthetic peptides and protein substrates showed that senile plaques contained the highest levels of enzymatically active cathepsin. At the ultrastructural level, cathepsin immunoreactivity in senile plaques was localized principally to lysosomal dense bodies and lipofuscin granules, which were extracellular. Similar structures were abundant in degenerating neurons of Alzheimer neocortex, and cathepsin-laden neuronal perikarya in various stages of disintegration could be seen within some senile plaques. The high levels of enzymatically competent lysosomal proteases abnormally localized in senile plaques represent evidence for candidate enzymes that may mediate the proteolytic formation of amyloid. We propose that amyloid precursor protein within senile plaques is processed by lysosomal proteases principally derived from degenerating neurons. Escape of cathepsins from the stringently regulated intracellular milieu provides a basis for an abnormal sequence of proteolytic cleavages of accumulating amyloid precursor protein.

Integrated genomic profiling of endometrial carcinoma associates aggressive tumors with indicators of PI3 kinase activation.

Although 75% of endometrial cancers are treated at an early stage, 15% to 20% of these recur. We performed an integrated analysis of genome-wide expression and copy-number data for primary endometrial carcinomas with extensive clinical and histopathological data to detect features predictive of recurrent disease. Unsupervised analysis of the expression data distinguished 2 major clusters with strikingly different phenotypes, including significant differences in disease-free survival. To identify possible mechanisms for these differences, we performed a global genomic survey of amplifications, deletions, and loss of heterozygosity, which identified 11 significantly amplified and 13 significantly deleted regions. Amplifications of 3q26.32 harboring the oncogene PIK3CA were associated with poor prognosis and segregated with the aggressive transcriptional cluster. Moreover, samples with PIK3CA amplification carried signatures associated with in vitro activation of PI3 kinase (PI3K), a signature that was shared by aggressive tumors without PIK3CA amplification. Tumors with loss of PTEN expression or PIK3CA overexpression that did not have PIK3CA amplification also shared the PI3K activation signature, high protein expression of the PI3K pathway member STMN1, and an aggressive phenotype in test and validation datasets. However, mutations of PTEN or PIK3CA were not associated with the same expression profile or aggressive phenotype. STMN1 expression had independent prognostic value. The results affirm the utility of systematic characterization of the cancer genome in clinically annotated specimens and suggest the particular importance of the PI3K pathway in patients who have aggressive endometrial cancer.

Scaffold-based three-dimensional human fibroblast culture provides a structural matrix that supports angiogenesis in infarcted heart tissue.

BACKGROUND We have developed techniques to implant angiogenic patches onto the epicardium over regions of infarcted cardiac tissue to stimulate revascularization of the damaged tissue. These experiments used a scaffold-based 3D human dermal fibroblast culture (3DFC) as an epicardial patch. The 3DFC contains viable cells that secrete angiogenic growth factors and has previously been shown to stimulate angiogenic activity. The hypothesis tested was that a viable 3DFC cardiac patch would stimulate an angiogenic response within an area of infarcted cardiac tissue. METHODS AND RESULTS A coronary occlusion of a branch of the left anterior descending coronary artery was performed by thermal ligation in severe combined immunodeficient mice. 3DFCs with or without viable cells were sized to the damaged area, implanted in replicate mice onto the epicardium at the site of tissue injury, and compared with animals that received infarct surgery but no implant. Fourteen and 30 days after surgery, hearts were exposed and photographed, and tissue samples were prepared for histology and cytochemistry. Fourteen and 30 days after surgery, the damaged myocardium receiving viable 3DFC exhibited a significantly greater angiogenic response (including arterioles, venules, and capillaries) than nonviable and untreated control groups. CONCLUSIONS In this animal model, viable 3DFC stimulates angiogenesis within a region of cardiac infarction and can augment a repair response in damaged tissue. Therefore, a potential use for 3DFC is the repair of myocardial tissue damaged by infarction.

Processing of the beta-amyloid precursor. Multiple proteases generate and degrade potentially amyloidogenic fragments.

Proteolytic processing of the beta-amyloid precursor proteins (APP) is required for release of the beta/A4 protein and its deposition into the amyloid plaques characteristic of aging and Alzheimer's disease. We have examined the involvement of acidic intracellular compartments in APP processing in cultured human cells. The use of acidotropic agents and inhibitors to a specific class of lysosomal protease, coupled with metabolic labeling and immunoprecipitation, revealed that APP is degraded within an acidic compartment to produce at least 12 COOH-terminal fragments. Nine likely contain the entire beta/A4 domain and, therefore, are potentially amyloidogenic. Treatment with E64 or Z-Phe-Ala-CHN2 irreversibly blocked activities of the lysosomal cysteine proteases cathepsins B and L but did not inhibit the lysosomal aspartic protease cathepsin D and did not alter the production of potentially amyloidogenic fragments. Instead, the inhibitors prevented further degradation of the fragments. Thus, large numbers of potentially amyloidogenic fragments of APP are routinely generated in an acidic compartment by noncysteine proteases and then are eliminated within lysosomes by cysteine proteases. Immunoblot and immunohistochemical analyses confirmed that chronic cysteine protease inhibition leads to accumulation of potentially amyloidogenic APP fragments in lysosomes. The results provide further support for the hypothesis that an acidic compartment may be involved in amyloid formation and begin to define the proteolytic events that may be important for amyloidogenesis.

A specific amyloid-β protein assembly in the brain impairs memory

Memory function often declines with age, and is believed to deteriorate initially because of changes in synaptic function rather than loss of neurons. Some individuals then go on to develop Alzheimer's disease with neurodegeneration. Here we use Tg2576 mice, which express a human amyloid-β precursor protein (APP) variant linked to Alzheimer's disease, to investigate the cause of memory decline in the absence of neurodegeneration or amyloid-β protein amyloidosis. Young Tg2576 mice (< 6 months old) have normal memory and lack neuropathology, middle-aged mice (6–14 months old) develop memory deficits without neuronal loss, and old mice (> 14 months old) form abundant neuritic plaques containing amyloid-β (refs 3–6). We found that memory deficits in middle-aged Tg2576 mice are caused by the extracellular accumulation of a 56-kDa soluble amyloid-β assembly, which we term Aβ*56 (Aβ star 56). Aβ*56 purified from the brains of impaired Tg2576 mice disrupts memory when administered to young rats. We propose that Aβ*56 impairs memory independently of plaques or neuronal loss, and may contribute to cognitive deficits associated with Alzheimer's disease.

Expression of the gene encoding the chemorepellent semaphorin III is induced in the fibroblast component of neural scar tissue formed following injuries of adult but not neonatal CNS.

This study evaluates the expression of the chemorepellent semaphorin III (D)/collapsin-1 (sema III) following lesions to the rat CNS. Scar tissue, formed after penetrating injuries to the lateral olfactory tract (LOT), cortex, perforant pathway, and spinal cord, contained numerous spindle-shaped cells expressing high levels of sema III mRNA. The properties of these cells were investigated in detail in the lesioned LOT. Most sema III mRNA-positive cells were located in the core of the scar and expressed proteins characteristic for fibroblast-like cells. Neuropilin-1, a sema III receptor, was expressed in injured neurons with projections to the lesion site, in a subpopulation of scar-associated cells and in blood vessels around the scar. In contrast to lesions made in the mature CNS, LOT transection in neonates did not induce sema III mRNA expression within cells in the lesion and was followed by vigorous axonal regeneration. The concomitant expression of sema III and its receptor neuropilin-1 in the scar suggests that sema III/neuropilin-1-mediated mechanisms are involved in CNS scar formation. The expression of the secreted chemorepellent sema III following CNS injury provides the first evidence that chemorepulsive semaphorins may contribute to the inhibitory effects exerted by scars on the outgrowth of injured CNS neurites. The vigorous regrowth of injured axons in the absence of sema III following early neonatal lesions is consistent with this notion. The inactivation of sema III in scar tissue by either antibody perturbation or by genetic or pharmacological intervention could be a powerful means to promote long-distance regeneration in the adult CNS.

Frailty Syndrome: A Transitional State in a Dynamic Process

Frailty has long been considered synonymous with disability and comorbidity, to be highly prevalent in old age and to confer a high risk for falls, hospitalization and mortality. However, it is becoming recognized that frailty may be a distinct clinical syndrome with a biological basis. The frailty process appears to be a transitional state in the dynamic progression from robustness to functional decline. During this process, total physiological reserves decrease and become less likely to be sufficient for the maintenance and repair of the ageing body. Central to the clinical concept of frailty is that no single altered system alone defines it, but that multiple systems are involved. Clinical consensus regarding the phenotype which constitutes frailty, drawing upon the opinions of numerous authors, shows the characteristics to include wasting (loss of both muscle mass and strength and weight loss), loss of endurance, decreased balance and mobility, slowed performance, relative inactivity and, potentially, decreased cognitive function. Frailty is a distinct entity easily recognized by clinicians, with multiple manifestations and with no single symptom being sufficient or essential in its presentation. Manifestations include appearance (consistent or not with age), nutritional status (thin, weight loss), subjective health rating (health perception), performance (cognition, fatigue), sensory/physical impairments (vision, hearing, strength) and current care (medication, hospital). Although the early stages of the frailty process may be clinically silent, when depleted reserves reach an aggregate threshold leading to serious vulnerability, the syndrome may become detectable by looking at clinical, functional, behavioral and biological markers. Thus, a better understanding of these clinical changes and their underlying mechanisms, beginning in the pre-frail state, may confirm the impression held by many geriatricians that increasing frailty is distinguishable from ageing and in consequence is potentially reversible. We therefore provide an update of the physiopathology and clinical and biological characteristics of the frailty process and speculate on possible preventative approaches.

Endogenous gamma-H2AX-ATM-Chk2 checkpoint activation in Bloom's syndrome helicase deficient cells is related to DNA replication arrested forks.

The Bloom syndrome helicase (BLM) is critical for genomic stability. A defect in BLM activity results in the cancer-predisposing Bloom syndrome (BS). Here, we report that BLM-deficient cell lines and primary fibroblasts display an endogenously activated DNA double-strand break checkpoint response with prominent levels of phosphorylated histone H2AX (gamma-H2AX), Chk2 (p(T68)Chk2), and ATM (p(S1981)ATM) colocalizing in nuclear foci. Interestingly, the mitotic fraction of gamma-H2AX foci did not seem to be higher in BLM-deficient cells, indicating that these lesions form transiently during interphase. Pulse labeling with iododeoxyuridine and immunofluorescence microscopy showed the colocalization of gamma-H2AX, ATM, and Chk2 together with replication foci. Those foci costained for Rad51, indicating homologous recombination at these replication sites. We therefore analyzed replication in BS cells using a single molecule approach on combed DNA fibers. In addition to a higher frequency of replication fork barriers, BS cells displayed a reduced average fork velocity and global reduction of interorigin distances indicative of an elevated frequency of origin firing. Because BS is one of the most penetrant cancer-predisposing hereditary diseases, it is likely that the lack of BLM engages the cells in a situation similar to precancerous tissues with replication stress. To our knowledge, this is the first report of high ATM-Chk2 kinase activation and its linkage to replication defects in a BS model.

In vivo electroporation in the embryonic mouse central nervous system

This protocol describes a basic method for in vivo electroporation in the nervous system of embryonic mice. Delivery of electric pulses following microinjection of DNA into the brain ventricle or the spinal cord central canal enables efficient transfection of genes into the nervous system. Transfection is facilitated by forceps-type electrodes, which hold the uterus and/or the yolk sac containing the embryo. More than ten embryos in a single pregnant mouse can be operated on within 30 min. More than 90% of operated embryos survive and more than 90% of these survivors express the transfected genes appropriately. Gene expression in neurons persists for a long time, even at postnatal stages, after electroporation. Thus, this method could be used to analyze roles of genes not only in embryonic development but also in higher order function of the nervous system, such as learning.

Serum amyloid A: An acute-phase protein involved in tumour pathogenesis

The synthesis of acute-phase protein serum amyloid A (SAA) is largely regulated by inflammation- associated cytokines and a high concentration of circulating SAA may represent an ideal marker for acute and chronic inflammatory diseases. However, SAA is also synthesized in extrahepatic tissues, e.g. human carcinoma metastases and cancer cell lines. An increasing body of in vitro data supports the concept of involvement of SAA in carcinogenesis and neoplastic diseases. Accumulating evidence suggests that SAA might be included in a group of biomarkers to detect a pattern of physiological events that reflect the growth of malignancy and host response. This review is meant to provide a broad overview of the many ways that SAA could contribute to tumour development, and accelerate tumour progression and metastasis, and to gain a better understanding of this acute-phase reactant as a possible link between chronic inflammation and neoplasia.

Long-term inhibition of dipeptidyl peptidase-4 in Alzheimer's prone mice.

We tested here the impact of a long-term inhibition of dipeptidyl peptidase-4 (DPP-4) with sitagliptin on the deposition of amyloid-beta within the brain and deficits in memory-related behavioral paradigms in a model of Alzheimer's disease (AD): double transgenic mice B6*Cg-Tg(APPswe,PSEN1dE9)85Dbo/J. Mice began to receive sitagliptin at 7 months of age. Three different dose of sitagliptin (5, 10 and 20 mg/kg), were administered daily for 12 weeks by gastric gavage. The treatments counteracted: (i) the memory impairment in the contextual fear conditioning test; (ii) increased the brain levels of GLP-1; (iii) produced significant reductions of nitrosative stress and inflammation hallmarks within the brain, as well as (iv) a significant diminution in the ultimate number and total area of betaAPP and Abeta deposits. All these effects much more evident for the dose of 20 mg/kg sitagliptin. The long-term inhibition of the endogenous DPP-4 enzymes with sitagliptin can significantly delay some forms of AD pathology, including amyloid deposition, when administered early in the disease course of a transgenic mouse model of AD.

Enhancement of proteasome function by PA28α overexpression protects against oxidative stress.

The principal function of the proteasome is targeted degradation of intracellular proteins. Proteasome dysfunction has been observed in experimental cardiomyopathies and implicated in human congestive heart failure. Measures to enhance proteasome proteolytic function are currently lacking but would be beneficial in testing the pathogenic role of proteasome dysfunction and could have significant therapeutic potential. The association of proteasome activator 28 (PA28) with the 20S proteasome may play a role in antigen processing. It is unclear, however, whether the PA28 plays any important role outside of antigen presentation, although up-regulation of PA28 has been observed in certain types of cardiomyopathy. Here, we show that PA28α overexpression (PA28αOE) stabilized PA28β, increased 11S proteasomes, and enhanced the degradation of a previously validated proteasome surrogate substrate (GFPu) in cultured neonatal rat cardiomyocytes. PA28αOE significantly attenuated H(2)O(2)-induced increases in the protein carbonyls and markedly suppressed apoptosis in cultured cardiomyocytes under basal conditions or when stressed by H(2)O(2). We conclude that PA28αOE is sufficient to up-regulate 11S proteasomes, enhance proteasome-mediated removal of misfolded and oxidized proteins, and protect against oxidative stress in cardiomyocytes, providing a highly sought means to increase proteasomal degradation of abnormal cellular proteins.

A rare mutation in UNC5C predisposes to late-onset Alzheimer's disease and increases neuronal cell death

We have identified a rare coding mutation, T835M (rs137875858), in the UNC5C netrin receptor gene that segregated with disease in an autosomal dominant pattern in two families enriched for late-onset Alzheimer's disease and that was associated with disease across four large case-control cohorts (odds ratio = 2.15, Pmeta = 0.0095). T835M alters a conserved residue in the hinge region of UNC5C, and in vitro studies demonstrate that this mutation leads to increased cell death in human HEK293T cells and in rodent neurons. Furthermore, neurons expressing T835M UNC5C are more susceptible to cell death from multiple neurotoxic stimuli, including β-amyloid (Aβ), glutamate and staurosporine. On the basis of these data and the enriched hippocampal expression of UNC5C in the adult nervous system, we propose that one possible mechanism in which T835M UNC5C contributes to the risk of Alzheimer's disease is by increasing susceptibility to neuronal cell death, particularly in vulnerable regions of the Alzheimer's disease brain.

Cycling Quiescence in Temozolomide Resistant Glioblastoma Cells Is Partly Explained by microRNA-93 and -193-Mediated Decrease of Cyclin D

Glioblastoma multiforme (GBM) is a fatal malignancy of the central nervous system, commonly associated with chemoresistance. The alkylating agent Temozolomide (TMZ) is the front-line chemotherapeutic agent and has undergone intense studies on resistance. These studies reported on mismatch repair gene upregulation, ABC-targeted drug efflux, and cell cycle alterations. The mechanism by which TMZ induces cell cycle arrest has not been well-established. TMZ-resistant GBM cells have been linked to microRNA (miRNA) and exosomes. A cell cycle miRNA array identified distinct miRNAs only in exosomes from TMZ-resistant GBM cell lines and primary spheres. We narrowed the miRs to miR-93 and -193 and showed in computational analyses that they could target Cyclin D1. Since Cyclin D1 is a major regulator of cell cycle progression, we performed cause-effect studies and showed a blunting effects of miR-93 and -193 in Cyclin D1 expression. These two miRs also decreased cell cycling quiescence and induced resistance to TMZ. Taken together, our data provide a mechanism by which GBM cells can exhibit TMZ-induced resistance through miRNA targeting of Cyclin D1. The data provide a number of therapeutic approaches to reverse chemoresistance at the miRNA, exosomal and cell cycle points.

Targeted nanoparticles containing the proresolving peptide Ac2-26 protect against advanced atherosclerosis in hypercholesterolemic mice

Chronic, nonresolving inflammation is a critical factor in the clinical progression of advanced atherosclerotic lesions. In the normal inflammatory response, resolution is mediated by several agonists, among which is the glucocorticoid-regulated protein called annexin A1. The proresolving actions of annexin A1, which are mediated through its receptor N-formyl peptide receptor 2 (FPR2/ALX), can be mimicked by an amino-terminal peptide encompassing amino acids 2–26 (Ac2-26). Collagen IV (Col IV)–targeted nanoparticles (NPs) containing Ac2-26 were evaluated for their therapeutic effect on chronic, advanced atherosclerosis in fat-fed Ldlr−/− mice. When administered to mice with preexisting lesions, Col IV–Ac2-26 NPs were targeted to lesions and led to a marked improvement in key advanced plaque properties, including an increase in the protective collagen layer overlying lesions (which was associated with a decrease in lesional collagenase activity), suppression of oxidative stress, and a decrease in plaque necrosis. In mice lacking FPR2/ALX in myeloid cells, these improvements were not seen. Thus, administration of a resolution-mediating peptide in a targeted NP activates its receptor on myeloid cells to stabilize advanced atherosclerotic lesions. These findings support the concept that defective inflammation resolution plays a role in advanced atherosclerosis, and suggest a new form of therapy.

Neurite sprouting and synapse deterioration in the aging Caenorhabditis elegans nervous system.

Caenorhabditis elegans is a powerful model for analysis of the conserved mechanisms that modulate healthy aging. In the aging nematode nervous system, neuronal death and/or detectable loss of processes are not readily apparent, but because dendrite restructuring and loss of synaptic integrity are hypothesized to contribute to human brain decline and dysfunction, we combined fluorescence microscopy and electron microscopy (EM) to screen at high resolution for nervous system changes. We report two major components of morphological change in the aging C. elegans nervous system: (1) accumulation of novel outgrowths from specific neurons, and (2) physical decline in synaptic integrity. Novel outgrowth phenotypes, including branching from the main dendrite or new growth from somata, appear at a high frequency in some aging neurons, but not all. Mitochondria are often associated with age-associated branch sites. Lowered insulin signaling confers some maintenance of ALM and PLM neuron structural integrity into old age, and both DAF-16/FOXO and heat shock factor transcription factor HSF-1 exert neuroprotective functions. hsf-1 can act cell autonomously in this capacity. EM evaluation in synapse-rich regions reveals a striking decline in synaptic vesicle numbers and a diminution of presynaptic density size. Interestingly, old animals that maintain locomotory prowess exhibit less synaptic decline than same-age decrepit animals, suggesting that synaptic integrity correlates with locomotory healthspan. Our data reveal similarities between the aging C. elegans nervous system and mammalian brain, suggesting conserved neuronal responses to age. Dissection of neuronal aging mechanisms in C. elegans may thus influence the development of brain healthspan-extending therapies.

Confusion and memory loss from capsular genu infarction: a thalamocortical disconnection syndrome?

We examined six patients with an abrupt change in behavior after infarction involving the inferior genu of the internal capsule. The acute syndrome featured fluctuating alertness, inattention, memory loss, apathy, abulia, and psychomotor retardation, suggesting frontal lobe dysfunction. Contralateral hemiparesis and dysarthria were generally mild, except when the infarct extended into the posterior limb. Neuropsychological testing in five patients with left-sided infarcts revealed severe verbal memory loss. Additional cognitive deficits consistent with dementia occurred in four patients. A right-sided infarct caused transient impairment in visuospatial memory. Functional brain imaging in three patients showed a focal reduction in hemispheric perfusion most prominent in the ipsilateral inferior and medial frontal cortex. We infer that the capsular genu infarct interrupted the inferior and anterior thalamic peduncles, resulting in functional deactivation of the ipsilateral frontal cortex. These observations suggest that one mechanism for cognitive deterioration from a lacunar infarct is thalamocortical disconnection of white-matter tracts, in some instances leading to "strategic-infarct dementia. "

The mammalian target of rapamycin signaling pathway mediates epileptogenesis in a model of temporal lobe epilepsy.

Understanding molecular mechanisms mediating epileptogenesis is critical for developing more effective therapies for epilepsy. We recently found that the mammalian target of rapamycin (mTOR) signaling pathway is involved in epileptogenesis, and mTOR inhibitors prevent epilepsy in a mouse model of tuberous sclerosis complex. Here, we investigated the potential role of mTOR in a rat model of temporal lobe epilepsy initiated by status epilepticus. Acute kainate-induced seizures resulted in biphasic activation of the mTOR pathway, as evident by an increase in phospho-S6 (P-S6) expression. An initial rise in P-S6 expression started approximately 1 h after seizure onset, peaked at 3-6 h, and returned to baseline by 24 h in both hippocampus and neocortex, reflecting widespread stimulation of mTOR signaling by acute seizure activity. After resolution of status epilepticus, a second increase in P-S6 was observed in hippocampus only, which started at 3 d, peaked 5-10 d, and persisted for several weeks after kainate injection, correlating with the development of chronic epileptogenesis within hippocampus. The mTOR inhibitor rapamycin, administered before kainate, blocked both the acute and chronic phases of seizure-induced mTOR activation and decreased kainate-induced neuronal cell death, neurogenesis, mossy fiber sprouting, and the development of spontaneous epilepsy. Late rapamycin treatment, after termination of status epilepticus, blocked the chronic phase of mTOR activation and reduced mossy fiber sprouting and epilepsy but not neurogenesis or neuronal death. These findings indicate that mTOR signaling mediates mechanisms of epileptogenesis in the kainate rat model and that mTOR inhibitors have potential antiepileptogenic effects in this model.

Molecular mechanisms underlying tumor dormancy.

Evidence suggests that dormant, microscopic tumors are not only common, but are highly prevalent in otherwise healthy individuals. Due to their small size and non-invasive nature, these dormant tumors remain asymptomatic and, in most cases, undetected. With advances in diagnostic imaging and molecular biology, it is now becoming clear that such neoplasms can remain in an asymptomatic, dormant stage for considerable periods of time without expanding in size. Although a number of processes may play a role in thwarting the expansion of microscopic tumors, one critical mechanism behind tumor dormancy is the ability of the tumor population to induce angiogenesis. Although cancer can arise through multiple pathways, it is assumed that essentially most tumors begin as microscopic, non-angiogenic neoplasms which cannot expand in size until vasculature is established. It is now becoming clear that cancer does not progress through a continuous exponential growth and mass expansion. Clinical cancer is usually manifested only in late, unavoidably symptomatic stages of the disease when tumors are sufficiently large to be readily detected. While dormancy in primary tumors is best defined as the time between the carcinogenic transformation event and the onset of inexorable progressive growth, it can also occur as minimal residual or occult disease from treated tumors or as micro-metastases. The existence of dormant tumors has important implications for the early detection and treatment of cancer. Elucidating the regulatory machinery of these processes will be instrumental in identifying novel early cancer biomarkers and could provide a rationale for the development of dormancy-promoting tumor therapies. Despite the high prevalence of microscopic, dormant tumors in humans and the significant clinical implications of their early detection, this area in cancer research has, to date, been under-investigated. In this mini review observations, models and experimental approaches to study tumor dormancy are summarized. Additionally, analogies and distinctions between the concepts of "tumor dormancy" and that of the "cellular dormancy" of tumor cells, as well as between the "exit from tumor dormancy" and the "onset of the angiogenic switch" are discussed.

Life and death of cardiac stem cells: a paradigm shift in cardiac biology.

The recognition that myocyte mitosis occurs in the fetal, neonatal, adult, and hypertrophied heart and that a pool of primitive, undifferentiated cells is present in the myocardium has put forward a different view of the biology of the heart. The new paradigm suggests that myocyte formation is preserved during postnatal life, in adulthood or senescence, pointing to a remarkable growth reserve of the heart throughout the course of life of the organism. This article reviews a large body of novel information, which has been obtained in the last 2 decades, in favor of the notion that the mammalian heart has the inherent ability to continuously replace its parenchymal cells and that this unexpected characteristic has important implications in understanding myocardial homeostasis, cardiac aging, and tissue repair. The paradigm that the heart is a postmitotic organ incapable of regenerating parenchymal cells was established in the 1970s, and this dogma has profoundly conditioned basic and clinical research in cardiology for the last 3 decades. On the basis of this paradigm, cardiomyocytes undergo cellular hypertrophy1,2 but cannot be replaced either by entry into the cell cycle of a subpopulation of nonterminally differentiated myocytes or by activation of a pool of primitive cells that become committed to the myocyte lineage. The only response of cardiomyocytes to stress is hypertrophy and/or death. Therefore, a tremendous effort was made to identify the molecular mechanisms of myocyte hypertrophy and their genetic control. A sophisticated knowledge of various signaling pathways has been achieved, and our understanding of the biology of hypertrophic myocyte growth has advanced markedly.3 An array of new technologies has been introduced that has led to a scientific revolution in terms of questions, approaches, and interpretation of experimental results. Despite this enormous progress in our understanding of basic mechanisms of hypertrophy, however, very little …

Purkinje cell compartments in the reeler mutant mouse as revealed by Zebrin II and 90-acetylated glycolipid antigen expression

The cerebellum is organized into a series of parasagittally aligned bands that may be revealed histologically in the adult mouse by largely complementary immunostaining of Purkinje cell sets with the monoclonal antibodies Zebrin II (ZII; antigen:aldolase C) and P-path (PP; antigen:90-acetyl glycolipids). We compared the normal staining pattern using these markers and an antibody to calbindin with that found in the reeler mutants (rl/rl), in which most Purkinje cell migration is halted beneath the cerebellar white matter. The results revealed that Purkinje cells in reeler mutants, despite their ectopic location in large subcortical masses, show a clear tendency to distribute into alternating zones that either stain for Zebrin II or for P-path, with variable transition zones of mixed labeling. However, the estimated number of zones was fewer than in the normal adult cortex: roughly 7–9 zones are revealed per side in the mutant compared with 14 major divisions in wild type mice. These results raise the possibility that neurons destined to express these markers are segregated during their migration and that the final phase of migration into the cortex might involve further splitting or interdigitation between cell sets expressing the two antigens.

The threshold for polyglutamine-expansion protein aggregation and cellular toxicity is dynamic and influenced by aging in Caenorhabditis elegans.

Studies of the mutant gene in Huntington's disease, and for eight related neurodegenerative disorders, have identified polyglutamine (polyQ) expansions as a basis for cellular toxicity. This finding has led to a disease hypothesis that protein aggregation and cellular dysfunction can occur at a threshold of approximately 40 glutamine residues. Here, we test this hypothesis by expression of fluorescently tagged polyQ proteins (Q29, Q33, Q35, Q40, and Q44) in the body wall muscle cells of Caenorhabditis elegans and show that young adults exhibit a sharp boundary at 35-40 glutamines associated with the appearance of protein aggregates and loss of motility. Surprisingly, genetically identical animals expressing near-threshold polyQ repeats exhibited a high degree of variation in the appearance of protein aggregates and cellular toxicity that was dependent on repeat length and exacerbated during aging. The role of genetically determined aging pathways in the progression of age-dependent polyQ-mediated aggregation and cellular toxicity was tested by expressing Q82 in the background of age-1 mutant animals that exhibit an extended lifespan. We observed a dramatic delay of polyQ toxicity and appearance of protein aggregates. These data provide experimental support for the threshold hypothesis of polyQ-mediated toxicity in an experimental organism and emphasize the importance of the threshold as a point at which genetic modifiers and aging influence biochemical environment and protein homeostasis in the cell.

Prediction of coronary artery disease by a systemic atherosclerosis score index derived from whole-body MR angiography

BACKGROUND Whole-body magnetic resonance angiography (WB-MRA) has shown its potential for the non-invasive assessment of nearly the entire arterial vasculature within one examination. Since the presence of extra-cardiac atherosclerosis is associated with an increased risk of coronary events, our goal was to establish the relationship between WB-MRA findings, including a systemic atherosclerosis score index, and the presence of significant coronary artery disease (CAD). METHODS WB-MRA was performed on a 1.5T scanner in 50 patients scheduled to undergo elective cardiac catheterization for suspected CAD. In each patient, 40 extra-cardiac vessel segments were evaluated and assigned scores according to their luminal narrowing. The atherosclerosis score index (ASI) was generated as the ratio of summed scores to analyzable segments. RESULTS ASI was higher in patients with significant (> 50% stenosis) CAD (n = 27) vs. patients without CAD (n = 22; 1.56 vs. 1.28, p = 0.004). ASI correlated with PROCAM (R = 0.57, p < 0.001) and Framingham (R = 0.36, p = 0.01) risk scores as estimates of the 10-year risk of coronary events. A ROC derived ASI of > 1.54 predicted significant CAD with a sensitivity of 59%, specificity of 86% and a positive predictive value of 84%. Logistic regression revealed ASI > 1.54 as the strongest independent predictor for CAD with a 11-fold increase in likelihood to suffer from significant coronary disease. On the contrary, while 15/27 (55%) of patients with CAD exhibited at least one extra-cardiac stenosis > 50%, only 3/22 (14%) of those patients without CAD did (p = 0.003). The likelihood for an extra-cardiac stenosis when CAD is present differed between vascular territories and ranged from 15% for a carotid stenosis to 44% for a stenosis in the lower extremities. CONCLUSION This study provides important new evidence for the close association of extra-cardiac and coronary atherosclerosis. The novel findings that a WB-MRA derived systemic atherosclerosis score index is not only associated with established cardiovascular risk scores but is also predictive of significant CAD suggest its potential prognostic implications and underline the importance to screen for coronary disease in patients with extra-cardiac manifestations of atherosclerosis.

The FASEB Journal express article 10.1096/fj.00-0815fje. Published online June 27, 2001. Essential role for cholesterol in synaptic plasticity and neuronal degeneration

SPECIFIC AIMSOur previous studies implied the relation between lipid metabolism and amyloid beta protein (Aβ) as ‘a missing link in Alzheimer’s puzzle’ [FASEB J., vol. 12, p. 1097 (1998)]. In the present study, we evaluated the role of cholesterol in synaptic plasticity and neuronal degeneration by a combination of adult rat hippocampal slice technology, a well-established procedure for limited cholesterol efflux, lipid metabolic labeling, extracellular recording of CA1 field excitatory postsynaptic potentials (fEPSPs), and immunofluorescence. PRINCIPAL FINDINGS1. Increased cholesterol efflux impairs short- and long-term synaptic plasticitySynaptic plasticity is a fundamental feature of the central nervous system (CNS) that allows synapses to ‘remember’ previous activity and express plastic changes to fine-tune current synaptic action. In this study, we asked whether an increased cholesterol efflux induced ex vivo by normal human CSF-HDL3 and methyl-β-cyclodextrin (MβCD) (a natural and model cholesterol ac...

Mesenchymal-endothelial-transition contributes to cardiac neovascularization

Endothelial cells contribute to a subset of cardiac fibroblasts by undergoing endothelial-to-mesenchymal transition, but whether cardiac fibroblasts can adopt an endothelial cell fate and directly contribute to neovascularization after cardiac injury is not known. Here, using genetic fate map techniques, we demonstrate that cardiac fibroblasts rapidly adopt an endothelial-cell-like phenotype after acute ischaemic cardiac injury. Fibroblast-derived endothelial cells exhibit anatomical and functional characteristics of native endothelial cells. We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate. Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function. Conversely, stimulation of the p53 pathway in cardiac fibroblasts augments mesenchymal-to-endothelial transition, enhances vascularity and improves cardiac function. These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.

Modeling neurogenesis impairment in Down syndrome with induced pluripotent stem cells from Trisomy 21 amniotic fluid cells.

Down syndrome (DS), or Trisomy 21 (T21) syndrome, one of the most common chromosomal abnormalities, is caused by an extra duplication of chromosome 21. In studies of neuron development, experimental models based on human cells are considered to be the most desired and accurate for basic research. The generation of diseased induced pluripotetn stem (iPS) cell is a critical step in understanding the developmental stages of complex neuronal diseases. Here, we generated human DS iPS cell lines from second trimester amniotic fluid (AF) cells with T21 by co-expressing Yamanaka factors through lentiviral delivery and subsequently differentiated them into neuronal progenitor cells (NPCs) for further analyses. T21 AF-iPS cells were characterized for the expression of pluripotent markers and for their ability to differentiate into all three germ layers by forming embryoid bodies in vitro and teratomas in vivo. The T21 AF-iPS cells maintained their unique pattern of chromosomal karyotypes: three pairs of chromosome 21. The level of amyloid precursor protein was significantly increased in NPCs derived from T21 AF-iPS cells compared with NPCs from normal AF-iPS cells. The expression levels of miR-155 and miR-802 in T21 AF-iPS-NPCs were highly elevated in the presence of low expression of MeCP2. We observed that T21 iPS-NPCs generated fewer neurons compared with controls. T21 iPS-NPCs exhibit developmental defects during neurogenesis. Our findings suggest that T21 AF-iPS cells serve as a good source to further elucidate the impairment neurogenesis of DS and the onset of Alzheimer's disease.

Applicability of current staging/categorization of α-synuclein pathology and their clinical relevance

In Parkinson's disease (PD) and dementia with Lewy bodies (DLB) alpha-synuclein (alphaS) pathology is seen that displays a predictable topographic distribution. There are two staging/categorization systems, i.e. Braak's and McKeith's, currently in use for the assessment of alphaS pathology. The aim of these diagnostic strategies in pathology is, in addition to assess the stage/severity of pathology, to assess the probabilities of the related clinical symptomatology i.e. dementia and extrapyramidal symptoms (EPS). Herein, we assessed the applicability of these two staging/categorization systems and the frequency of dementia and EPS in a cohort of 226 alphaS-positive-subjects. These subject were selected from a large autopsy sample (n = 1,720), irrespective of the clinical presentation, based on the detection of alphaS-immunoreactivity (IR) in one of the most vulnerable nuclei; in the dorsal motor nucleus of vagus, substantia nigra and basal forebrain. The frequency of alphaS-IR lesions in this large cohort was 14% (248 out of 1,720). If applicable, each of the 226 subjects with all required material available was assigned a neuropathological stage/category of PD/DLB and finally the neuropathological data was analyzed in relation to dementia and EPS. 83% of subjects showed a distribution pattern of alphaS-IR that was compatible with the current staging/categorization systems. Around 55% of subjects with widespread alphaS pathology (Braak's PD stages 5-6) lacked clinical signs of dementia or EPS. Similarly, in respect to those subjects that fulfilled the McKeith criteria for diffuse neocortical category and displaying only mild concomitant Alzheimer's disease-related pathology, only 48% were demented and 54% displayed EPS. It is noteworthy that some subjects (17%) deviated from the suggested caudo-rostral propagation suggesting alternative routes of progression, perhaps due to concomitant diseases and genetic predisposition. In conclusion, our results do indeed confirm that current staging/categorization systems can readily be applied to most of the subjects with alphaS pathology. However, finding that around half of the subjects with abundant alphaS pathology remain neurologically intact is intriguing and raises the question whether we do assess the actual disease process.

Thymic expression of the golli-myelin basic protein gene in the SJL/J mouse

The T cell antigen-specific repertoire is thought to be shaped by thymic expression of self molecules. Since a myelin basic protein (MBP)-like gene (golli-MBP) has been reported to be expressed by cells of the immune system, the present study was undertaken to determine whether the golli-MBP gene was expressed in the mouse thymus and, if so, to characterize transcripts of this gene in this organ. Using exon-specific primers for MBP and golli-MBP, cDNA from thymus and other tissues was amplified, and the amplified products analyzed by Southern blotting with exon-specific oligonucleotide probes. The amplified products were subcloned, and the inserts characterized by DNA sequencing. The thymic transcripts were found to contain golli-MBP exons 1, 2, 3, 5A, 5B, 5C, 6, 7, 8, and 11.

Impact of aortic stiffness on survival in end-stage renal disease.

BACKGROUND Damage to large arteries is a major factor in the high cardiovascular morbidity and mortality of patients with end-stage renal disease (ESRD). Increased arterial stiffness and intima-media thickness, together with increased pulse pressure, are the principal arterial alterations. Whether increased aortic pulse-wave velocity (PWV), a classic marker of increased arterial stiffness, may predict all-cause and/or cardiovascular mortality has never been investigated. METHODS AND RESULTS A cohort of 241 patients with ESRD undergoing hemodialysis was studied between April 1987 and April 1998. The mean duration of follow-up was 72+/-41 months (mean+/-SD). Mean age at entry was 51.5+/-16.3 years. Seventy-three deaths occurred, including 48 cardiovascular and 25 noncardiovascular fatal events. At entry, together with standard clinical and biochemical analyses, patients underwent echocardiography and aortic PWV measured by Doppler ultrasonography. On the basis of Cox analyses, 2 factors emerged as predictors of all-cause and cardiovascular mortality: age and aortic PWV. Hemoglobin and low diastolic pressure interfered to a smaller extent. After adjustment for all the confounding factors, an OR for PWV >12. 0 versus <9.4 m/s was 5.4 (95% CI, 2.4 to 11.9) for all-cause mortality and 5.9 (95% CI, 2.3 to 15.5) for cardiovascular mortality. For each PWV increase of 1 m/s in our study population, all-cause mortality-adjusted OR was 1.39 (95% CI, 1.19 to 1.62). CONCLUSIONS These results provide the first direct evidence that in patients with ESRD, increased aortic stiffness determined by measurement of aortic PWV is a strong independent predictor of all-cause and mainly cardiovascular mortality.

Prion-like activity of Cu/Zn superoxide dismutase: implications for amyotrophic lateral sclerosis.

Neurodegenerative diseases belong to a larger group of protein misfolding disorders, known as proteinopathies. There is increasing experimental evidence implicating prion-like mechanisms in many common neurodegenerative disorders, including Alzheimer disease, Parkinson disease, the tauopathies, and amyotrophic lateral sclerosis (ALS), all of which feature the aberrant misfolding and aggregation of specific proteins. The prion paradigm provides a mechanism by which a mutant or wild-type protein can dominate pathogenesis through the initiation of self-propagating protein misfolding. ALS, a lethal disease characterized by progressive degeneration of motor neurons is understood as a classical proteinopathy; the disease is typified by the formation of inclusions consisting of aggregated protein within and around motor neurons that can contribute to neurotoxicity. It is well established that misfolded/oxidized SOD1 protein is highly toxic to motor neurons and plays a prominent role in the pathology of ALS. Recent work has identified propagated protein misfolding properties in both mutant and wild-type SOD1, which may provide the molecular basis for the clinically observed contiguous spread of the disease through the neuroaxis. In this review we examine the current state of knowledge regarding the prion-like properties of SOD1 and comment on its proposed mechanisms of intercellular transmission.

Relevance of asystole during head-up tilt testing.

The prognosis of patients manifesting prolonged asystole during head-up tilt testing is unclear. In 209 consecutive patients with a history of syncope and positive head-up tilt tests, 19 had asystole lasting > 5 seconds (mean duration 15 +/- 10) (group 1a). When compared with patients without asystole (group 1b), group 1a patients were younger (32 +/- 12 vs 47 +/- 21 years, p < 0.005), but clinical manifestations were not any more dramatic (the number of episodes of syncope [7 +/- 5 vs 8 +/- 6 episodes, p = NS] and injury during syncope [2 vs 13 patients, p = NS] were similar). During follow-up (mean 2 +/- 1 year), with the patient taking pharmacologic therapy such as beta blockers, ephedrine, theophylline, or disopyramide, the recurrence rate was 11% and 8% in groups 1a and 1b (p = NS). No patient in the asystole group underwent pacemaker implantation. Additionally, of 75 normal volunteers (group 2) with no history of syncope undergoing tilt tests to define its specificity, 3 had asystole (mean duration 10 seconds). During > 1 year of follow-up, despite no treatment, all 3 are symptom free. Thus, asystole during head-up tilt testing does not predict either a more malignant outcome or a poor response to pharmacologic therapy. Moreover, an asystolic response does not enhance the specificity of the head-up tilt test because it may be present in asymptomatic "normal" volunteers.

From bloodjournal.hematologylibrary.org at PENN STATE UNIVERSITY on February 23, 2013. For personal use only.

Megakaryocyte (MK) is the naturally polyploid cell that gives rise to platelets. Polyploidization occurs by endomitosis, which was a process considered to be an incomplete mitosis aborted in anaphase. Here, we used time-lapse confocal video microscopy to visualize the endomitotic process of primary human megakaryocytes. Our results show that the switch from mitosis to endomitosis corresponds to a late failure of cytokinesis accompanied by a backward movement of the 2 daughter cells. No abnormality was observed in the central spindle of endomitotic MKs. A furrow formation was present, but the contractile ring was abnormal because accumulation of nonmuscle myosin IIA was lacking. In addition, a defect in cell elongation was observed in dipolar endomitotic MKs during telophase. RhoA and F-actin were partially concentrated at the site of furrowing. Inhibition of the Rho/Rock pathway caused the disappearance of F-actin at midzone and increased MK ploidy level. This inhibition was associated with a more pronounced defect in furrow formation as well as in spindle elongation. Our results suggest that the late failure of cytokinesis responsible for the endomitotic process is related to a partial defect in the Rho/Rock pathway activation.