***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Cholesterol is an essential constituent of eukaryotic membranes and plays a crucial role in membrane organization , dynamics , function , and sorting . It is often found distributed non-r and omly in domains or pools in biological and model membranes and is thought to contribute to a segregated distribution of membrane constituents . Signal transduction events mediated by seven transmembrane domain G-protein coupled receptors ( GPCRs ) are the primary means by which cells communicate with and respond to their external environment . We analyzed the role of cholesterol in the plasma membrane organization of the G-protein coupled serotonin(1A ) receptor by fluorescence recovery after photobleaching ( FRAP ) measurements with varying bleach spot sizes . Our results show that lateral diffusion parameters of serotonin(1A ) receptors in normal cells are consistent with models describing diffusion of molecules in a homogenous membrane . Interestingly , these characteristics are altered in cholesterol-depleted cells in a manner that is consistent with dynamic confinement of serotonin(1A ) receptors in the plasma membrane . Importantly , analysis of lig and binding and downstream signaling of the serotonin(1A ) receptor suggests that receptor function is affected in a significantly different manner when intact cells or isolated membranes are depleted of cholesterol . These results assume significance in the context of interpreting effects of cholesterol depletion on diffusion characteristics of membrane proteins in particular , and cholesterol-dependent cellular processes in general Serum lipids have been associated with depression in the adult population ; however , this association during pregnancy remains unclear . The aim of this study was to evaluate the association between serum lipids and depressive symptom scores during pregnancy . A prospect i ve cohort of 238 pregnant women was followed at the 5th-13th , 20th-26th and 30th-36th weeks of gestation . Depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale ( EPDS ) . Serum concentrations ( mg/dL ) of triglycerides , total cholesterol , and  low- and high-density lipoproteins  ( LDL-c ; HDL-c ) were the main exposures . Marital status ( married/single ) , physical activity ( active or very active/low or very low active ) , unplanned pregnancy ( no/yes ) ,  pre-pregnancy BMI  ( < 25/≥ 25 kg/m(2 ) ) , generalized anxiety disorder ( no/yes ) and current suicidal ideation ( no/yes ) were considered as potential confounders . Analyses were performed using linear mixed-effects models . The results showed that the EPDS mean score ( 95%CI ) decreased with time during pregnancy trimesters [ 1st : 8.89 ( 95%CI = 8.28 - 9.51 ) , 2nd : 7.32 ( 95%CI = 6.67 - 7.97 ) and 3rd : 7.08 ( 95%CI = 6.41 - 7.74 ) ] . Suicidal ideation frequency at baseline was 18 % . HDL-c concentrations were inversely associated with changes in EPDS score ( β = -0.080 , 95%CI = -0.157 to -0.002 ) , while low or very low active women ( β = 1.288 , 95%CI = 0.630 - 1.946 ) , with single marital status ( β = 1.348 , 95%CI = 0.163 - 2.534 ) , unplanned pregnancy ( β = 1.922 , 95%CI = 0.714 - 3.131 ) , generalized anxiety disorder ( β = 2.139 , 95%CI = 0.410 - 3.868 ) and current suicidal ideation ( β = 1.927 , 95%CI = 0.596 - 3.258 ) tended to have higher EPDS scores . No relationship was observed between other lipids and EPDS scores . HDL-c concentration was inversely associated with changes in depressive symptom scores during pregnancy after adjusting for socio-economic , demographic , behavioral , nutritional , biochemical and mental health disorders BACKGROUND Lipids appear to mediate depressive vulnerability in the elderly ; however , sex differences and genetic vulnerability have not been taken into account in previous prospect i ve studies . METHODS  Depression  was assessed in a population of 1040 women and 752 men aged 65 years and older at baseline and after 7-year follow-up .  Clinical level of depression ( DEP ) was defined as having either a score of 16 or higher on the Centre for Epidemiology Studies Depression scale or a diagnosis of current major depression on the Mini-International Neuropsychiatric Interview . Lipid levels , apolipoprotein E , and serotonin transporter linked promoter region ( 5-serotonin transporter gene linked promoter region ) genotypes were evaluated at baseline . RESULTS Multivariate analyses adjusted by sociodemographic and behavioral variables , measures of physical health including ischemic pathologies , and genetic vulnerability indicated gender-specific associations between dyslipidemia and DEP , independent of the use of lipid-lowering agents or apolipoprotein E status . Men with low low-density lipoprotein cholesterol levels had twice the risk of prevalent and incident DEP , whereas in women low high-density lipoprotein cholesterol levels were found to be significantly associated with increased prevalent DEP ( odds ratio = 1.5 ) only . A significant interaction was observed between low low-density lipoprotein-cholesterol and 5-serotonin transporter gene linked promoter region genotype , men with s/s or s/l genotype being at increased risk of DEP ( odds ratio = 6.0 and 2.7 , respectively ) . No significant gene-environment interaction was observed for women . CONCLUSIONS DEP is associated with higher atherogenic risk in women ( low high-density lipoprotein cholesterol ) , whereas the reverse is observed in men ( low low-density lipoprotein cholesterol ) . Late-life depression may have a complex gender-specific etiology involving genetic vulnerability in men AIMS We investigated the longitudinal association of depression , with and without cognitive dysfunction , with hemoglobin A1c ( HbA1c ) , systolic blood pressure ( SBP ) , and low-density lipoprotein ( LDL ) in a predominantly minority cohort . METHODS There were 613 participants . Presence of depression was defined by a score ≥7 on the Short-CARE depression scale . We tested participants for executive dysfunction using the Color Trails Test ( CTT ) , part 2 , and for memory dysfunction using the total recall task of the Selective Reminding Test ( TR-SRT ) . We classified performance in these tests as abnormal based on st and ardized score cutoffs ( < 16th percentile and one st and ard deviation below the sample mean ) . R and om effects models were used to compare repeated measures of the diabetes control measures between those with depression versus those without depression and ever versus never cognitively impaired . RESULTS Baseline depression  was present in 36 % of participants . Over a median follow-up of 2 years , depression was not related to worse HbA1c , SBP , or LDL . The presence of ( 1 ) abnormal performance on a test of executive function and depression ( n=57 ) or ( 2 ) abnormal performance on a test of verbal recall and depression ( n=43 ) was also not associated with clinical ly significant worse change in diabetes control . CONCLUSIONS Depression , with or without low performance in tests of executive function and memory , may not affect clinical ly significant measures of diabetes control in the elderly This study compared the serum lipid concentrations in 100 patients with major depressive disorder ( MDD ) with those from 100 matched healthy controls . It was found that the serum total cholesterol concentration in patients with MDD ( 5.27 + /- 1.18 mmol/L ) was significantly lower than the value ( 6.63 + /- 1.32 mmol/L ) in sex- , age- , and weight-matched healthy controls . This significant decrease in serum cholesterol in patients with MDD was noted in both sexes and in all age groups . Patients with MDD , however , had significantly higher HDL cholesterol than matched controls . There were no statistically significant differences in serum concentrations of triglycerides , apolipoprotein ( Apo ) A1 , Apo B , transferrin , and albumin between patients and controls . Clinical recovery of patients with MDD was accompanied by a significant increase in serum total cholesterol from 5.27 + /- 1.18 mmol/L to 6.12 + /- 1.2 mmol/L. These results suggest an association between low serum total cholesterol and depression in both sexes and at all age groups BACKGROUND Cohort and case-control studies found that lower serum total cholesterol is associated with depression . It is , however , unclear whether low cholesterol or its lipoprotein fractions are causally related to depression . Using a Mendelian r and omization design , the potential association between apolipoprotein E ( APOE ) genotype ( affecting lifetime cholesterol levels ) and depressive symptoms was studied . METHODS In the longitudinal Finl and , Italy , the Netherl and s Elderly ( FINE ) Study 1089 men were included in 1985 . The 435 men from Finl and , 418 men from The Netherl and s , and 236 men from Italy ( aged 65 - 84 years ) were free of myocardial infa rct ion , stroke , diabetes mellitus and cancer at all time points . They were prospect ively studied around 1985 ( n=658 ) , 1990 ( n=668 ) , 1995 ( n=327 ) , and 2000 ( n=82 ) . Associations between serum cholesterol , lipoprotein fractions and APOE genotype , with depressive symptoms ( by Zung self-rating depression scale [ SDS ] ) were analyzed using multilevel regression models . RESULTS Serum total cholesterol was inversely associated with the Zung SDS ( -0.61 points per 1 mmol/L increase in cholesterol ; 95 % confidence interval : -1.05 to -0.17 ; P=0.007 ) , after adjustment for country , age , body mass index , smoking , and alcohol intake . However , none of the cholesterol lipoprotein fractions were associated with the Zung SDS . The APOE genotypes epsilon4/4 , epsilon4/3 ; epsilon3/3 ; epsilon4/2 , and epsilon3/2 or epsilon2/2 were associated with decreasing levels of serum total and LDL cholesterol ( Ps<0.001 ) , but not with increasing depressive symptoms ( P=0.67 ) . LIMITATIONS APOE genotype was assessed through protein isoforms and not actual DNA-based typing . CONCLUSIONS There was a modest inverse relationship between depression scores and serum total cholesterol in elderly men , but no associations with lipoprotein fractions or with the APOE genotype 
    Output:
    
This meta- analysis demonstrates a cross-sectional link between depression and low serum LDL