Preservation of brain nerve growth factor in mild cognitive impairment and Alzheimer disease

Background: The status of nerve growth factor (NGF) levels during the prodromal phase of Alzheimer disease (AD), characterized by mild cognitive impairment (MCI), remains unknown. Objective: To investigate whether cortical and/or hippocampal NGF levels are altered in subjects with MCI or different levels of AD severity. Design and Main Outcome Measures: An NGF enzyme-linked immunosorbent assay determined protein levels in the hippocampus and 5 cortical areas in people clinically diagnosed as having no cognitive impairment, MCI, mild AD, or severe AD. Setting and Patients: Subjects were from the Rush Religious Orders Study and the University of Pittsburgh Alzheimer's Disease Research Center (Pittsburgh, Pa). Results: We found no changes in cortical or hippocampal NGF levels across groups; in MCI, levels did not correlate with an increase in choline acetyltransferase activity in these regions. Conclusion: Brain NGF levels appear sufficient to support the cholinergic plasticity changes seen in MCI and remain stable throughout the disease course.