Blood-brain barrier abnormalities in Alzheimer's disease.

We studied the cerebral microcirculation and the blood-brain barrier in Alzheimer's disease by assessing the glucose transporter, several functionally important enzymes, and adrenergic receptors in isolated brain microvessels that were obtained at autopsy from subjects with Alzheimer's disease and from age-matched controls. We found a marked decrease of about 50% in the density of the glucose transporter, but increased densities of beta 2- and alpha 2-adrenergic receptors in cerebral microvessels obtained from subjects with Alzheimer's disease. The biologic implications of these findings are discussed.