Laminin concentrations in serum and cerebrospinal fluid in aging and Alzheimer's disease.

Laminin, a basement membrane protein, and a potent promoter of neurite outgrowth, surrounds all peripheral nerves. It appears in the central nervous system during development and reappears in response to injury. In Alzheimer's disease (AD), there is a progressive loss of neurons in specific areas of the brain along with the presence of an increased number of senile plaques and neurofibrillary tangles. Laminin levels have been shown to be increased in injury, so we undertook to examine levels of laminin by radioimmunoassay (RIA), in cerebrospinal fluid and serum of patients with AD and age-matched controls. No difference in the CSF and serum laminin concentrations was found between Alzheimer's disease and age-matched controls. We found a lack of correlation between severity of clinical dementia and laminin concentrations. Finally, we show that the CSF and serum laminin concentrations increase with age.