Measurement of laminins in the cerebrospinal fluid obtained from patients with Alzheimer's disease and vascular dementia using a modified enzyme-linked immunosorbent assay.

We developed a new enzyme-linked immunosorbent assay (ELISA) system using antibodies against intact human laminin, laminin alpha(5)-chain, laminin beta(1)-chain, laminin gamma(1)-chain and laminin alpha(1)-chain peptide (YFQRYLI). Using this ELISA, we measured the anti-laminin immunoreactivity levels in the cerebrospinal fluid (CSF) obtained from patients with Alzheimer's disease (AD), vascular dementia (VaD), and other disorders. The present study showed the levels of certain laminins in CSF to demonstrate significant differences in the chain levels in different dementias. The AD group showed a significantly lower level of anti-laminin gamma(1) immunoreactivity. The late-onset AD group showed significantly elevated anti-laminin alpha(1)-peptide (YFQRYLI) immunoreactivity levels in comparison with the early-onset AD group and controls. On the other hand, the VaD group showed significantly higher levels of anti-intact human laminin and anti-laminin beta(1) immunoreactivity. The assays of anti-laminin immunoreactivity levels in CSF provided an efficient sensitivity (85.0%) and specificity (93.7%) for the diagnosis of AD by using the ratio of tau to anti-intact human laminin immunoreactivity levels. These results suggest that CSF laminin or its derivatives may correlate with the pathogenesis of AD and VaD, and the prevention of the proteolytic activity may be an effective therapeutic method for either preventing or slowing down the progression of AD. Furthermore, it was shown that performing ELISA for CSF laminins may prove to be useful for detecting the biological markers of AD and VaD.