A vascular connection to Alzheimer's disease.

Alzheimer"s disease (AD) is characterized by a progressive and debilitating dementia in elderly people. The causes of this disease are not known, but major risk factors include old age and a family history of dementia, Down"s syndrome, female gender, low level of education, and head injury. There is no known cure for Alzheimer"s disease. The disease is characterized by abnormal accumulation of amyloid-beta peptide and the protein Tau in the nerve cells and extracellular space of certain regions of the brain. Cerebral amyloid angiopathy is another marker for Alzheimer"s disease. In autopsies, small cerebral arterial blood vessels and capillaries show signs of inflammation, amyloid accumulations, and a focal breach of the blood-brain barrier. This review focuses on the results of recent investigations of vascular responses to infusion of amyloid-beta(1-40), the means of preventing vascular damage, using a live animal (rat) model, and the combination of intravital video recordings of the mesenteric microvascular bed with electron microscopic analyses of the same vascular segments. We propose that the cerebral vascular changes in patients with Alzheimer"s disease probably precede the neuronal damage and dementia.