Researchers find insulin link to dementia

A key step: They now know what causes brain shrinkage

MONTE WHALEY; The Denver Post | • Published November 06, 2009

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FORT COLLINS, Colo. – Colorado State University researchers think insulin levels in the brain may be the key to understanding how some types of dementia progress.

Low levels of both insulin and insulin-like growth factors appear to cause cell loss and the shrinking of the brain that results in dementia, the researchers found.

Douglas Ishii, a professor in the department of biomedical sciences at Colorado State and the lead researcher in the study, said the findings offer real hope that the progression of dementia in people with conditions such as Alzheimer’s, diabetes and Parkinson’s disease may someday be prevented.

“This has been the Holy Grail in the Alzheimer’s field – halting the progression of this terrible disease,” Ishii said.

The study will be published in the next issue of the journal Brain Research. The research was funded by the National Institute of Neurological Diseases and Stroke, Centers for Disease Control and Prevention, and Colorado Commission on Higher Education.

Ishii, who began studying the role of insulin in brain development more than 25 years ago, cautioned that more research – including clinical trials – will be required.

Likewise, the Alzheimer’s Association of Colorado is heartened by Ishii’s work, but said much more research is needed before the fight against dementia can be declared over.

More than 5 million Americans have dementia. About 10 million baby boomers are projected to get Alzheimer’s. By 2010, there will be nearly a half million new cases of Alzheimer’s diagnosed annually; and by 2050, there will be nearly a million new cases per year, according to the Alzheimer’s Association.

Before the discovery by Ishii’s group, researchers did not understand what causes the brain to shrink. That made it impossible for the medical field to develop ways to slow, stop or reverse conditions like Alzheimer’s.

Current treatments for dementia include medications that delay the progression of symptoms, but the brain continues to shrink.

The treatments don’t work for long because scientists have not yet figured out how to get medications across the barrier between blood and brain. Likewise, even though a person who has Alzheimer’s or diabetes might have high levels of insulin in his blood, the insulin in the brain may be abnormally low because of a blockage in the blood-brain barrier, the researchers explained.