Link found between insulin and memory increase for those with Alzheimer’s

31 October 2009

Seattle - Researchers at VA Puget Sound Health Care System and the University of Washington published an article today in Journal of Alzheimer’s Disease showing a promising connection between insulin and increased memory in persons with Alzheimer’s disease or at risk of developing the disease. The study also found promising increases in memory for people who are cognitively intact.

Alzheimer’s disease is the most common progressive memory disorder among older adults. Alzheimer’s robs patients first of the ability to learn new information, then of the ability to function independently and finally of a sense of personal identity. Insulin is a hormone [or chemical messenger] that is best known for regulating blood sugar. Recent research suggests that it plays a role in memory and that it helps regulate levels of beta-amyloid, one of the primary proteins associated with Alzheimer’s. In other words, persons with Alzheimer’s have increased levels of beta-amyloid deposited in their brains.

These researchers have consistently shown that giving older adults a moderate dose of insulin could facilitate memory. Findings from this study replicated and extended previous work by showing that both insulin and octreotide facilitate memory in memory-impaired and cognitively intact older adults. (Octreotide is a synthetic hormone that mimics the actions of somatostatin, a natural hormone that regulates insulin release) “These exciting findings add weight to a growing awareness that what happens in the brain is related to what happens in the body” note Dr. Stennis Watson, VA Puget Sound researcher and Assistant Professor at the Department of Psychiatry and Behavioral Sciences University of Washington School of Medicine. “The foods we eat, the air we breathe, the exercise we get and the medications that we take all have implications for our ability to think.”

Watson adds, “we are convinced that insulin holds one of the keys to understanding why Alzheimer’s disease develops and how to treat this dreaded disease. We anticipate that our work will help to demonstrate that both lifestyle interventions and medications will bring hope to older adults.”

It has been previously reported that insulin regulates memory for both Alzheimer’s-affected and cognitively intact persons, and that octreotide regulates memory in memory-impaired patients. The current study reports that octreotide also regulates memory in cognitively-intact older adults.  The clinical implication is that both insulin and somatostatin are potential targets for the development of novel strategies to treat Alzheimer’s.

The  article, "Effects of insulin and octreotide on memory and growth hormone in Alzheimer's disease", (G. Stennis Watson, Laura D. Baker, Brenna A. Cholerton, Kristoffer W. Rhoads, George R. Merriam, Gerard D. Schellenberg, Sanjay Asthana, Monique Cherrier, Suzanne Craft S.) will be published in the November 2009 issue of Journal of Alzheimer's Disease.

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