DETECTION OF NGF-LIKE ACTIVITY IN HUMAN BRAIN-TISSUE - INCREASED LEVELS IN ALZHEIMERS-DISEASE

A two-site ELISA and a bioassay were used to detect NGF-like activity in human brain tissue. Both assays detected mouse NGF and recombinant human NGF with approximately equal sensitivity, whereas the antibodies showed little cross-reactivity with the recombinant human proteins NT -3 and brain-derived neurotrophic factor. NGF-like activity was detect ed in fresh human cortical samples obtained from epileptic patients, w ith the highest activity observed in the right hemisphere of men. NGF- like activity was subsequently measured in autopsy samples of frontal and occipital cortex from patients with Alzheimer's disease (AD) and f rom individuals with no history or pathological evidence of AD. Based on both the ELISA and the bioassay measurements, NGF-like activity was significantly elevated in both brain regions in AD. These results dem onstrate the feasibility of detecting NGF-like activity in both fresh and postmortem human brain tissue and further suggest that AD is chara cterized by increased, rather than decreased, levels of cortical beta- NGF. The AD-related increase in NGF may be a consequence of degenerati ve changes in the basal forebrain cholinergic system.