More On Alzheimer's as Type 3 Diabetes
The Scientist looks at recent thinking on Alzheimer's: "accumulated evidence suggests that insulin and insulin-like growth factor signaling is impaired in patients with Alzheimer's disease. ... It looks like in Alzheimer's disease you end up having a defect in these kinds of pathways, which are similar to the pathways for insulin-resistant diabetes ... But, it's unknown as to which comes first, the disease or the insulin resistance, although de la Monte is confident that the signaling defects precede the disease. As for a decrease in insulin in the brain 'if that deficit is important, we don't know.' ... In July of this year, Morris White at Children's Hospital Boston found that insulin might actually be bad for the brain. He knocked out insulin signaling in mice and found that they live nearly 20% longer. Although he didn't conduct a cognitive assay, the animals appeared more resistant to oxidative stress, which should be protective against neurodegeneration. 'Attenuated insulin signaling in the brain is probably a good thing.' ... Excess insulin is also thought to compete with amyloid plaques for degradation, thereby contributing to their nefarious accumulation in the brains of Alzheimer's patients. White says that while these results appear to oppose de la Monte's findings that insulin deficiency is the problem, he agrees that approaching Alzheimer's as a diabetes-like disorder is a good direction to follow."