[Proteoglycans in senile dementia of Alzheimer's type].

Levels of the proteoglycans hyaluronic acid, heparan sulfate, dermatan sulfate and chondroitin sulfate in brains were measured. The samples were from 25 brains obtained at autopsy from patients who had senile dementia of Alzheimer's type (SDAT) (60 to 97 years old) and 10 brains from non-demented elderly subjects (75 to 101 years old). Proteoglycan levels in the brains of patients with SDAT were twice as high in the hippocampus and four times higher in the superior frontal gyrus than the levels in brains of non-demented elderly subjects. The content of heparan sulfate proteoglycan was greatest nine times higher in the hippocampus and seven times higher in the superior frontal gyrus. By immuno-electronmicroscopic examination, heparan sulfate proteoglycan was found in the basement membranes of capillaries, and in a portion of the cores of the senile plaques.