For a variety of serious neurodegenerative diseases, there exist no effective therapies or cures. For example, Parkinson's disease is a progressive and ultimately fatal neurodegenerative disorder characterized by loss of the pigmented dopaminergic neurons of the substantia nigra. The symptoms of Parkinson's disease often can be managed initially by administration of L-DOPA, the immediate precursor of dopamine. However, reduced efficacy of L-DOPA treatment typically occurs over time. Programmed cell death (apoptosis) has been implicated in this neurodegenerative disorder.
In Alzheimer's disease, the most common neurodegenerative disease and most frequent cause of dementia, progressive failure of memory and degeneration of temporal and parietal association cortex result in speech impairment and loss of coordination, and, in some cases, emotional disturbance. Alzheimer's disease generally progresses over many years, with patients gradually becoming immobile, emaciated and susceptible to pneumonia.
Neuroprotective therapy has been sought for a variety of acute and chronic neurological conditions, including stroke, Parkinson's disease, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, epilepsy and pain. Present therapies are relatively ineffective or are accompanied by unwanted side effects. In particular, erythropoietin (EPO) can be neuroprotective when administered in high doses; however, such doses also promote the formation of new red blood cells, consequently causing side effects such as “sludging” of the blood and leading to increased risk of stroke. Thus, there is a need for novel methods of using erythropoietin to achieve neuroprotection, that do not rely on excessively high doses of the factor. The present invention satisfies this need and provides related advantages as well.