Health Watch -- Insulin and Alzheimer's Disease

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Could there be a link between diabetes and Alzheimer's disease?

Low levels of an enzyme that degrades insulin could raise the risk for Alzheimer's disease. That's according to the results of a laboratory study conducted by researchers at UT Southwestern Medical Center at Dallas.

The researchers found that the enzyme insulysin, which degrades insulin, also degrades amyloid-beta peptides. When amyloid-beta levels rise, it raises the risk for Alzheimer's disease. The disease is marked by a build-up of amyloid plaques in the brain.

Researchers studied mice that were missing insulysin gene activity to determine what effect low levels of the enzyme might have. Besides finding the connection to amyloid-beta peptides, they also found that even a partial decrease of insulysin activity raised amyloid-beta levels in the brain.

Dr. Bonnie Miller, one of the UT Southwestern researchers who led the study, said that the results were exciting because they point to a new mechanism that may contribute to Alzheimer's disease.

The next step for researchers is to determine if low insulysin levels actually do result in an increased risk for Alzheimer's disease. In the future, understanding how and why peptides build up in the brain could help researchers find ways to stop that build-up, and maybe even prevent Alzheimer's disease, which affects more than 4 million Americans.