Alzheimer’s and diabetes linked
People with diabetes have a significantly higher risk of also developing Alzheimer’s disease. US researchers now say they have identified the probable molecular basis for the diabetes-Alzheimer’s connection.
This latest news follows a study that found heavy drinkers and heavy smokers develop Alzheimer’s disease years earlier than people with Alzheimer’s who do not drink or smoke heavily. Now, the diabetes link takes centre stage.
In a study published in the current online issue of the journal Neurobiology of Aging, investigators at the Salk Institute for Biological Studies report that blood vessels in the brains of young diabetic mice are damaged by the interaction of elevated blood glucose levels characteristic of diabetes and low levels of beta amyloid, a peptide that clumps to form the senile plaques that riddle the brains of Alzheimer’s patients.
While the damage took place long before the first plaques appeared, the mice suffered from significant memory loss and an increase in inflammation in the brain.
“Although the toxic beta amyloid peptide was first isolated from the brain blood vessels of Alzheimer’s patients, the contribution of pathological changes in brain vascular tissue to the disease has not been well studied,” said Dave R Schubert, PhD, head of Salk’s Cellular Neurobiology Laboratory. “Our data clearly describes a biochemical mechanism to explain the epidemiology, and identify targets for drug development.”
Alzheimer’s and diabetes are two diseases that are increasing at an alarming rate within the US population. Alzheimer’s affects one in 10 Americans over 65 years of age and nearly 50% of those over age 85. Similarly, 7% of the population – or approximately 20 million Americans – have diabetes, with the vast majority of these individuals older than 60.
Recent epidemiological studies have shown that diabetic patients have a 30% to 65% higher risk of developing Alzheimer’s disease compared to non-diabetic individuals. The increased risk applies to both type 1 and type 2 diabetes, which share hyperglycemia as a common pathogenic factor.
