"This study helps show how the brain's vascular system may contribute to the development of Alzheimer's disease," said study leader Berislav V. Zlokovic, M.D. Ph.D., director of the Zilkha Neurogenetic Institute at the Keck School of Medicine of the University of Southern California, Los Angeles. The study was co-funded by the National Institute of Neurological Diseases and Stroke (NINDS) and the National Institute on Aging (NIA), parts of the National Institutes of Health.

Alzheimer's disease is the leading cause of dementia. It is an age-related disease that gradually erodes a person's memory, thinking, and ability to perform everyday tasks. Brains from Alzheimer's patients typically have abnormally high levels of plaques made up of accumulations of beta-amyloid protein next to brain cells, tau protein that clumps together to form neurofibrillary tangles inside neurons, and extensive neuron loss.

Vascular dementias, the second leading cause of dementia, are a diverse group of brain disorders caused by a range of blood vessel problems. Brains from Alzheimer's patients often show evidence of vascular disease, including ischemic stroke, small hemorrhages, and diffuse white matter disease, plus a buildup of beta-amyloid protein in vessel walls. Furthermore, previous studies suggest that APOE4, a genetic risk factor for Alzheimer's disease, is linked to brain blood vessel health and integrity.

"This study may provide a better understanding of the overlap between Alzheimer's disease and vascular dementia," said Roderick Corriveau, Ph.D., a program director at NINDS.