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.