November 16, 2016
A study shows new ways in which diabetes, a disorder of blood sugar control, may be linked to Alzheimer’s disease. The studyfound that changes in the brain typical of Alzheimer’s disease are tied to changes in the way that the body processes blood sugar, or glucose. The findings, the authors say, raise the possibility that drugs to treat diabetes could one day be useful in the treatment of Alzheimer’s disease.
“Around 80 percent of people with Alzheimer’s disease also have some form of diabetes,” said Bettina Platt of the University of Aberdeen in Scotland, one of the study leaders and a researcher in Alzhiemer’s. She and a team of diabetes researchers looked at ways in which the brain abnormalities of Alzheimer’s disease are linked totype 2 diabetes, a disease of that often develops in those who are overweight.
For the study, published in the journal Diabetologia, the scientists looked at mice that were genetically bred to develop high levels of an enzyme called BACE1. The enzyme is tied to the buildup of toxic brain proteins typical of Alzheimer’s disease in people. They found that high levels of the enzyme can also lead to changes in the way the body processes blood sugar, setting the stage for diabetes.
“Until now, we always assumed that obese people get type 2 diabetes and then are more likely to get dementia,” Dr. Platt said. “Here we show that dysregulation in the brain can lead to the development of very severe diabetes, showing that diabetes doesn’t necessarily have to start with your body getting fat. It can start with changes in the brain.”
“We now think that some of the compounds that are used for obesity and diabetes might potentially be beneficial for Alzheimer’s patients as well,” Dr. Platt said.“There are a number of new drugs available right now which we are testing to see if they would reverse both Alzheimer’s and diabetes symptoms.”
It’s a long way from mice to people, and much more research is needed to explore the ties between Alzheimer’s and diabetes and any possible new treatments. But the findings add to a growing body of research linking diabetes with Alzheimer’s and other forms of dementia.
Diabetes is known to damage blood vessels throughout the body, including in the brain, and diabetes is a known risk factor for dementia. In a study from last year, researchers found that after just two years, men and women with diabetes had an impaired ability to regulate blood flow in the brain. The defects were linked to lower scores on tests of memory and thinking skills, and people with impaired blood flow were less able to carry out day-to-day activities like bathing and cooking. [See the Alzinfo.org story, “Diabetes Takes a Toll on the Brain,” at https://www.alzinfo.org/articles/diagnosis/diabetes-takes-a-toll-on-the-brain/ ]
Scientists have also found links between insulin, an crucial hormone that helps the body maintain healthy levels of blood sugar and that is used as a treatment for diabetes, and the memory problems of Alzheimer’s. [See the alzinfo.org story “Alzheimer’s Tied to Insulin Problems in the Brain,” at https://www.alzinfo.org/articles/alzheimers-tied-insulin-problems-brain/ ]Preliminary studies alsofound that delivering squirts of aerosolized insulin deep into the nose, where it can get into the brain, may improve memory and thinking skills in those with Alzheimer’s [see the ALZinfo.org story, “Insulin Nasal Spray Shows Promise as Alzheimer’s Treatment,” at https://www.alzinfo.org/articles/treatment/insulin-nasal-spray-shows-promise-as-alzheimers-treatment/ ]
Better understanding of the link between diabetes and Alzheimer’s could lead to better treatments for the devastating disease, though more study is needed before doctors should begin prescribing diabetes drugs for Alzheimer’s.Preventing diabetes in the first place may be one way to help maintain long-term brain health. Keeping weight down, getting regular exercise and eating a Mediterranean-style diet rich in fresh fruits and vegetables may all help to keep diabetes at bay – and in the process may help to stem the memory loss of Alzheimer’s.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: KajaPlucinska, RutaDekeryte, David Koss, et al: “Neuronal Human BACE1 Knockin Induces Systemic Diabetes in Mice.” Diabetologia Volume 59: pages 1513-1523, June 2016.