Serum alpha 1-antitrypsin and alpha 2-macroglobulin in Alzheimer's and Binswanger's disease.

The deposition of beta A4-amyloid in senile plaques and small cerebral vessels is one of the pathological hallmarks of Alzheimer's disease. Recent data suggest that protease inhibitors such as alpha 2-macroglobulin may be involved in the process of forming beta A4 amyloid deposits. Compared to 34 persons without neurological diseases, the serum content of alpha 1-antitrypsin was increased in 16 patients with Alzheimer's disease and 15 with Binswanger's disease. In the latter alpha 2-macroglobulin was also elevated in serum. Our results show no evidence of a blood-borne origin of the protein or peptid deposited in the walls of small vessels in Alzheimer's or Binswanger's disease. Nevertheless, the elevated proteinase inhibitor concentrations may play a role in the pathogenesis of these diseases.