Background: Alzheimer's disease (AD) is the most common cause of dementia in Western countries and in Japan. Numerous blood and cerebrospinal fluid (CSF) tests based on the disease pathology have been proposed for early detection of AD. By comparing the CSF proteome of AD patients and controls it might be possible to identify proteins that play a role in the disease process and thus study the pathogenesis of AD.
Patients and methods: Samples of CSF from normal (n=20) and AD patients (n=20) were collected by lumbar puncture. The total concentration of proteins in the CSF of normal subjects and AD patients was determined by Bio-Rad protein assay based on the Bradford dye binding procedure. The presence and level of NGF in the CSF of normal and AD patients was measured by enzyme-linked immunosorbent assay (ELISA), SDS-PAGE and western blot.
Results: The total protein concentration of all samples was within the normal range (0.10-0.44 g/L). A western blot analysis using anti-NGF antibody showed the presence of NGF in human CSF. By ELISA, the level of NGF in the CSF of AD patients was higher than in the CSF of normal subjects (81.5A+/-15.03 pg/mL vs. 4.2A+/-1.92 pg/mL, P<0.0001).
Conclusion: We suggest that the NGF level in the CSF may provide additional information in the differential diagnosis of AD. We also conclude that NGF could be significantly involved in the pathophysiology of AD.