HEALTH - Alzheimer's and Insulin

"Study Shows Insulin Spray Boosts Memory in Alzheimer's Patients" by Murrey Jacobson, PBS Newshour 9/12/2011

What if you could prevent or slow Alzheimer's disease just by giving patients nasal spray containing insulin, just once or twice a day after a meal?

Researchers have been exploring that possibility for some time. But a new study out Monday provides the best indications yet that such a treatment might provide some hope for helping at least early stage Alzheimer's patients.

Results from the trial -- a so-called Phase II trial designed to test the safety and early efficacy of such an approach -- were published in the Archives of Neurology*. Scientists tested 104 patients with either early to moderate-stage Alzheimer's or mild cognitive impairment (often a harbinger for Alzheimer's) to see how they responded to the insulin spray. Thirty-six participants received a moderate dose of the insulin spray twice a day for four months, 36 got double that dose, and 30 of the patients were on placebo.

The initial results were encouraging.

Compared to the placebo group, patients who took the moderate dose did 25 percent better on testing for memory than the placebo group over a four-month period, said Suzanne Craft, who led the research at the Veterans Affairs Puget Sound Health Care System and University of Washington School of Medicine. Craft will discuss the results on the NewsHour Monday.

"We also saw improvement on a test of general thinking by both groups that were treated with insulin," Craft said. "Their family members also said they showed a better ability to function daily like managing things at home, taking care of daily finances."

"The proof of principle here is important because it tells us that this area of study is important," said Craft. "Areas of insulin regulation are important targets for Alzheimer's Disease."

More than 5 million Americans have Alzheimer's, and that number is expected to swell in coming years as the population ages.

The idea behind the insulin trial, Craft said, is that researchers increasingly understand that insulin plays an important role in the brain in both supporting memory, processing new information and protecting against the toxic effects of proteins like beta-amyloid, which collects in the brains of people with Alzheimer's.

"Alzheimer's patients," she said, "seem to have a deficiency of insulin in their brains. This led to the hypothesis that if we were to supplement insulin, we might be able to improve their symptoms or the pathology that is causing the disease. We were searching ways to get insulin to the brain. What we came up with was administering it to the nose -- using a specialized device that targets insulin to the upper part of the naval cavity. Insulin reaches the brain within a 15 to 30-minute time-frame that way."

Doctors also took PET scans of some patients, comparing the decline of the glucose metabolism in the brains.

Patients who took a daily dose of insulin had less of a decline in that metabolism than the placebo group.

"I absolutely believe this is an important step forward," said Craft. "It needs to be taken to the next level of a Phase III trial (the gold standard) to see if it can be a therapy. At the very least we hope that if we can stabilize patients with mild cognitive impairment, they're quite functional. To stabilize that group would be a huge advantage. And there are reasons based on biology of what insulin does to examine whether it can do more than just stabilize pathology: Could it reverse or improve that pathology?"

Dr. Laurie Ryan, who oversees clinical trials of Alzheimer's Disease at NIH's Institute of Aging (which funded this study, too) cautioned that individuals should not place too much hope in a Phase II trial just yet.

"It's very encouraging," she said. "But there's not going to be just a single treatment for Alzheimer's. We're exploring this. We're also studying and testing other drugs and vaccines. There's not going to be a single magic bullet."

"I think there are several pathways to developing Alzheimer's disease," added Craft. "So an approach that might work for one group of patients might not work for another. And I think that makes things a bit more complicated. We'd like to have a one-size-fits-all approach, but that's not likely."