Did you know that people with type 1 or type 2 diabetes have a 30 to 65 percent greater risk for Alzheimer’s? Until now, researchers have been mystified as to the reason behind the link, but a recent study (published in the current online issue of Neurobiology of Aging by the Salk Institute for Biological Studies) has pinpointed the molecular connection.
David R. Schubert, Ph.D., professor in the Cellular Neurobiology Laboratory, and his team report that the cranial blood vessels of young diabetic mice sustain damage from the interplay between elevated blood sugar levels and low levels of beta amyloid, a peptide that forms the senile plaques in Alzheimer’s disease.
"Our data clearly describe a biochemical mechanism to explain the epidemiology, and identify targets for drug development," says Dave R. Schubert, Ph.D.
Salk researchers Schubert, Burdo and Qi Chen, along with diabetes expert Nigel Calcutt, a pathology professor at UCSD, selected mice whose genetics predisposed them to Alzheimer’s and then induced type 2 diabetes to study the damage to their vascular systems. The mice’s blood vessels became damaged long before they suffered overt signs of Alzheimer’s disease. The overproduction of free radicals, they determined, caused oxidative damage to linings of cells in cranial blood vessels.
"While all people have a low level of amyloid circulating in their blood, in diabetics there may be a synergistic toxicity between the amyloid and high level of blood glucose that is leading to the problems with proper blood vessel formation," says Burdo.
In the U.S., incidences of Alzheimer’s and type 2 diabetes are both growing at a concerning rate. 1 in 10 people over 65 develops Alzheimer’s and that jumps to nearly half of all people over 85. About 20 million Americans, most of whom are over 60, have either type 1 or type 2 diabetes. That figures out to be roughly 7 percent of the population.