Shannon Macauley, Ph.D., and David Holtzman M.D., neurology researchers involved in the study. (Source: Washington University School of Medicine in St. Louis)Diabetes and Alzheimer’s could have a cause-and-effect connection, according to a study published this week.

Elevated glucose in the blood caused increased levels of amyloid beta, a fundamental ingredient of brain plaques in Alzheimer’s brains, in mice analyzed by the team from the Washington University School of Medicine in St. Louis.

Although earlier studies had pointed to a possible connection between the two diseases over the last decade, the new study is the first to make a specific connection between the blood sugars and amino acids at the cellular level, the team said.

“Our results suggest that diabetes, or other conditions that make it hard to control blood sugar levels, can have harmful effects on brain function and exacerbate neurological conditions such as Alzheimer’s disease, said Shannon Macauley, a postdoctoral researcher at the school and the lead author.

Spikes in blood glucose increased the activity of the brain’s neurons, which promoted production of amyloid beta, according to the paper, published Monday in The Journal of Clinical Investigation.

The elevated glucose caused channels on the surface of brain cells called KATP channels to close, which excited the brain cells, making them more like to fire, the research showed. When those cells are excessively active, they produce more amyloid beta – leading potentially to Alzheimer’s development, they found.

To get those higher sugar levels, the researchers gave the mice diazoxide, a drug commonly used to treat low blood sugar. They injected the drug directly into the brain, to bypass the blood-brain barrier, they added.

“This observation opens up a new avenue of exploration for how Alzheimer’s disease develops in the brain as well as offe3rs a new therapeutic target for the treatment of this devastating neurologic disorder,” said Macauley.

Other studies have connected diabetes and Alzheimer’s – especially with advanced glycation end products, which are left behind after sugars are partially metabolized. As early as 2006, multiple studies presented at the Alzheimer’s Association international conference were drawing connections between the two diseases.