The two dominant proteins that determine how much blood flows through the body's arteries have been implicated in Alzheimer's disease, in a new study in the Jan. 16 issue of the Proceedings of the National Academy of Sciences. They offer new, surprising targets against Alzheimer's disease just as scientists are getting back in touch with the vascular roots of the disease that were first recognized early last century.
The research, putting proteins often linked to heart disease front and center in a brain disease whose causes remain a mystery, hark back to what German physician Alois Alzheimer noted when he first recognized the disease 100 years ago. Though Alzheimer noted changes in both the brain's cells and in the small arteries and capillaries that supply and drain blood to and from the brain, over the decades doctors separated the two concepts and have come to focus mainly on the toxic effects of the disease on cells. The changes to blood vessels have been pushed to the background.
The latest findings from the University of Rochester Medical Center mesh not only with Dr. Azheimer's initial observations but also with new findings from today's best imaging technologies. While the first visible symptom of Alzheimer's may be a person forgetting names or faces, the very first physical change is actually a decline in the amount of blood that flows in the brain. Doctors have found that not only is blood flow within the brain reduced, but that the body's capacity to allocate blood to different areas of the brain on demand is blunted in people with the disease.
"A reduction in blood flow precedes the decline in cognitive function in Alzheimer's patients," said Berislav Zlokovic, M.D., Ph.D., professor in the Department of Neurological Surgery and a neurovascular expert whose research is causing scientists to consider the role of reduced blood flow in Alzheimer's disease.