How type 2 diabetes can destroy memory with aging discovered

Kathleen Blanchard's picture
How uncontrolled type 2 diabetes leads to accelerated brain atrophy with aging.
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Uncontrolled type 2 diabetes accelerates aging changes in the brain. A known complication of diabetes is cognitive impairment. Now researchers have identified how diabetes affects the brain in older adults to destroy memory that can make even simple tasks difficult.

Beth Israel Deaconess Medical Center (BIDMC) researchers have been studying the effect of diabetes on the brain for the past five years to try to understand why people with type 2 diabetes develop memory problems and depression with aging.

The research team, led by neurophysiologist Vera Novak, MD, PhD, found two key molecules that attack the brain of diabetics and lead to atrophy – a decrease in the size of the brain.

The molecules - sVCAM and sICAM – cause inflammation that sets off a series of events affecting the blood vessels in the brain.

"In our previous work, we had found that patients with diabetes had significantly more brain atrophy than did a control group," explains Novak

"In fact, at the age of 65, the average person's brain shrinks about one percent a year, but in a diabetic patient, brain volume can be lowered by as much as 15 percent”, especially for people with uncontrolled blood sugar levels.

The areas of the brain most affected were the frontal, temporal and parietal regions. The researchers found subjects in the study with uncontrolled diabetes had greater blood vessel constriction, compared to a control group.

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The study included 147 people whose average age was 65 - seventy one had type 2 diabetes and were on diabetic medications for at least five years. The other 76 participants were age-matched and non-diabetic.

All of the participants underwent a series of tests to measure memory, inflammation markers in the bloodstream, balance and blood pressure.

The investigation showed high glucose levels in diabetics – hyperglycemia – is associated with higher inflammatory cytokines that lead to brain deterioration.

"It appears that chronic hyperglycemia and insulin resistance – the hallmarks of diabetes – trigger the release of adhesion molecules [sVCAM and sICAM] and set off a cascade of events leading to the development of chronic inflammation," says Novak. "Once chronic inflammation sets in, blood vessels constrict, blood flow is reduced, and brain tissue is damaged.”

The finding shows no organ is immune from the ravages of type 2 diabetes. The take-home message for the 25.8 million people living with the disease is that it’s important to follow diet, exercise and lifestyle guidelines to keep blood sugar levels in check.

The researchers hope identifying the biomarkers could lead to interventions to prevent brain problems associated with diabetes. They also note cognitive decline associated with type 2 diabetes has largely been neglected and should receive more focus.

Diabetes Care: doi: 10.2337/dc11-0969
"Adhesion Molecules, Altered Vasoreactivity, and Brain Atrophy in Type 2 Diabetes"
Vera Novak, MD, PHD et al.
November, 2011

Image credit: Wikimedia commons

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