Diabetes is a blow to the brain
Over the past five years, researchers at Beth Israel Medical Center, part of Harvard University, have been studying the effect of diabetes on the cognitive function of elderly people. They found that serious complications of this disease are memory loss, depression and other types of brain disorders. Recently, they were able to identify the key mechanism causing these violations.
According to the head of the work, Associate Professor Vera Novak, the results of an earlier study showed that, compared with the general population, the presence of diabetes significantly accelerates the atrophy of brain tissue in elderly people.
In diabetes, instead of entering the cells and being used as an energy source, glucose accumulates in the blood. This condition, known as hyperglycemia, is often accompanied by the development of chronic inflammatory processes. The researchers decided to find out whether chronic inflammation is the cause of the deterioration of blood flow in the brain of patients with diabetes.
To test their hypothesis, they examined 147 people whose average age was 65 years. 71 of the study participants had type 2 diabetes and had been taking blood glucose lowering medications for at least 5 years. The remaining 76 participants were part of a control group matched by age and sex ratio.
The study participants performed a series of tests on the level of cognitive function and the ability to maintain balance. Their blood pressure was measured, and blood tests were taken to determine the level of glucose and blood serum – to analyze the content of adhesive molecules and a number of other markers of the inflammatory status of the body. To assess the activity of blood flow in brain tissue and vascular reactivity, they underwent magnetic resonance imaging.
As the scientists expected, the results of tomography showed that, compared with the control group, patients with diabetes were characterized not only by a stronger narrowing of blood vessels, but also by a more pronounced atrophy of brain tissue, especially gray matter. The most affected in this case were the frontal, temporal and parietal parts of the cortex, responsible for such important functions as decision-making, speech, verbal memory and solving complex problems. The analysis of serum markers also confirmed the presence of a pronounced relationship between high glucose levels and elevated levels of proinflammatory cytokines.
Based on the data obtained, the researchers concluded that insulin resistance and hyperglycemia (the main symptoms of type 2 diabetes) trigger the release of adhesion molecules (sVCAM and sICAM) that cause the development of chronic inflammation of brain tissue. At the same time, a cascade of events is triggered, eventually leading to narrowing of blood vessels and atrophy of the tissues supplied with blood by them.
The results of the study provide specialists with two biomarkers of altered reactivity of brain vessels. Their timely detection will help to avoid the detrimental effect of diabetes on the brain. However, according to Novak, even more important is that the data obtained increase the list of reasons for the need for enhanced control over the course of diabetes and prevention of this common disease.
Article by Vera Novak et al. Adhesion Molecules, Altered Vasoreactivity, and Brain Atrophy in Type 2 Diabetes are published in the journal Diabetes Care.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Beth Israel Deaconess Medical Center:
Researchers Identify Link Between Diabetes and Cognitive Impairment in Older Adults.
09.11.2011