Alzheimer’s disease (AD) has long been feared as one of the most insidious and terrible of diseases to contract. Not only does it rob you of your sense of self, your memories and personality, but it has historically been nearly impossible to predict; for many people, it simply manifests late in life, and that uncertainty as to who will contract it or not has only added to the fear its name causes.
This is in part due because for many years Alzheimer’s has withstood our comprehension; we don’t know what causes it, or why it manifests in whom it does. Yet studies are being published providing new insight into the nature of this disease, and promising ever greater awareness of not only what it is, but why it occurs. The latest research suggests that this degenerative brain disease is actually a type of diabetes.
Dr. Suzanne de la Monte from Rhode Island Hospital recently published these findings, which were picked up by the Journal of Alzheimer’s Disease. Her research discovered that diabetes is closely linked to a number of key neuronal factors which are associated with the onset of dementia. Her discovery points to the conclusion that Alzheimer’s develops as a result of the brain becoming resistant to insulin, which causes fat (lipids) to accumulate in the brain as they fail to be metabolized. This results in increased stress and inflammation, and ultimately Alzheimer’s.
"This study points out that once Alzheimer's Disease is established, therapeutic efforts should target several different pathways — not just one," says Dr. de la Monte. "The reason is that a positive feedback loop gets going, making AD progress. We have to break the vicious cycle. Restoring insulin responsiveness and insulin depletion will help, but we need to reduce brain stress and repair the metabolic problems that cause the brain to produce toxins."
An earlier study in the International Journal of Alzheimer’s Disease reported that several symptoms of type 2 diabetes are commonly seen during the onset of Alzheimer’s, such as metabolic disregulation, insulin resistance or deficiency, and the abnormal use of glucose. These similarities led them to conclude that Alzheimer’s can be considered a form of type 3 diabetes, and that type 2 diabetes can be seen as increasing the risk of developing AD.
Another recent study from the University of Medicine and Dentistry at New Jersey (UMDNJ) worked with mice as patients to illustrate several of the close connections between AD and diabetes. They discovered that there are notable increases of amyloid beta peptide pathology in the brain during the onset of both AD and diabetes, and that examining the retina for the presence of amyloid beta could be a possible source of early warning for the onset of AD.
Finally, the new connection has provided light on a previous mystery, the activity and presence of oligomers, which are made up of amyloid beta. This recent study from UMDNJ has shown them to be the catalyst for further insulin resistance in the neurons they attach to, which triggers a diabetic reaction that forms more oligomers, endlessly making the situation worse.
All of these latest discoveries and research into the connection between diabetes and AD point the way to identifying potential biomarkers for doctors to identify AD before it begins to manifest, and potentially lead to the discovery of new drugs and prevention of AD.
Brain photograph courtesy of frostnova.
Scientist photograph courtesy of Army Medicine.