High Insulin Levels Linked to Alzheimer's

(Ivanhoe Newswire) -- Irregularities in insulin levels affect the inflammatory network and may be a factor in Alzheimer's disease (AD), according to a new study.

Led by Mark A. Fishel, M.D., from the University of Washington in Seattle, researchers raised the blood-level of 16 healthy adults between ages 55 and 81. After fasting, participants received a 105-minute infusion of either saline or insulin. Researchers then collected plasma and cerebrospinal fluid samples.

Study authors say, "Our findings suggest that insulin-resistant conditions such as diabetes mellitus and hypertension may increase the risk for AD, in part through insulin-induced inflammation." The study shows excessive insulin levels modulate the inflammatory network and increase inflammatory markers, elevating the levels of beta-amyloid in plasma and cerebrospinal fluid concentrations.

"Although this model has obvious relevance for diabetes mellitus, hyperinsulinemia and insulin resistance are widespread conditions that affect many nondiabetic adults with obesity, impaired glucose tolerance, cardiovascular disease, and hypertension," researchers say. "Our results provide a cautionary note for the current epidemic of such conditions, which, in the context of an aging population, may provoke a dramatic increase in the prevalence of AD."

Researchers conclude the growing understanding of insulin's role will be extremely beneficial in treating, delaying or preventing the onset of AD.

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SOURCE: Archives of Neurology, 2005:62