With rising obesity, America faces an increased number of type 2 diabetes cases. With an aging Baby Boom generation, the country is bracing for an increase in Alzheimer's disease.
Could the two be related?
Previous studies have hinted at such a link. But researchers at Washington University School of Medicine in St. Louis say they have nailed down the connection.
Their study, using mice, found that elevated glucose in the blood – a primary consequence of diabetes -- can rapidly increase levels of amyloid beta, which shows up in brain plaques in Alzheimer’s patients. The buildup of these plaques is believed to be what brings on the memory loss that Alzheimer’s causes in the brain.
Could lead to new treatments
“Our results suggest that diabetes, or other conditions that make it hard to control blood sugar levels, can have harmful effects on brain function and exacerbate neurological conditions such as Alzheimer’s disease,” said lead author Shannon Macauley, a postdoctoral research scholar. “The link we’ve discovered could lead us to future treatment targets that reduce these effects.”
There are two types of diabetes, type 1 mostly hereditary and the other, type 2, usually brought on by lifestyle factors, such as being overweight or obese. In both types the patient is unable to control glucose, or sugar levels in their blood.
Diabetes patients usually take insulin or other medication to keep their blood sugar where it is supposed to be.
So what does blood sugar have to do with Alzheimer's? To explore the linkage the researchers fed glucose to mice with an Alzheimer's-like condition.
If the mice did not have the amyloid plaques in the brains, doubling their blood glucose levels increased amyloid beta levels in the brain by 20%. When the scientists repeated the experiment in older mice that already had developed brain plaques, amyloid beta levels rose by 40%.
When blood glucose levels spiked, it increased brain activity that helped produce amyloid beta.
“This observation opens up a new avenue of exploration for how Alzheimer’s disease develops in the brain as well as offers a new therapeutic target for the treatment of this devastating neurologic disorder,” Macauley said.
Speeds up aging
Meanwhile, researchers at the University of Pittsburgh Graduate School of Public Health say they have found another link between diabetes and diminished memory function. They studied the brains of people with type 1 diabetes and found these brains aged faster, correlating with slower information processing.
Among the middle-aged test subjects who underwent an MRI, 33% of those with type 1 diabetes showed signs of damage to the brain's white matter. Only 7% of subjects who were not diabetic showed similar damage.
The researchers suggest middle-aged patients with type 1 diabetes should be screened for cognitive difficulties. If cognitive issues are progressive, they say these changes could influence a patients ability to manage his or her diabetes.