Could insulin fight dementia in patients with Down syndrome?

Early-onset dementia wasn't as much of a concern for people with Down syndrome three decades ago, when their life expectancy was 25, but it's a problem gaining more attention now that people with the genetic disorder are living into their senior years.

Bloomington-based HealthPartners has launched a clinical trial to see if insulin, taken in inhaled doses, can stop the degenerative process in the brains of people with Down syndrome. Research has shown that they suffer the same buildup of beta-amyloid plaque that is found in the brains of people with Alzheimer's disease — only they suffer it much earlier.

"Almost all these patients have amyloid changes in their brain by age 35. That's quite remarkable," said Dr. Michael Rosenbloom, who is leading the study for the HealthPartners Center for Memory and Aging. "By age 50, greater than 50 percent of them have dementia."

Insulin theoretically helps fight dementia in several ways, including breaking down amyloid plaque, when delivered directly to the brain and central nervous system. A special nasal inhaler is used to make sure the insulin reaches the upper third of the nasal sinus and travels to the brain from there. Otherwise the drug — normally used to regulate blood sugar in the treatment of diabetes — could slip into the bloodstream and disrupt a patient's metabolism.

"Presumably, when you give the drug through the nose, it stays in the central nervous system," Rosenbloom said. "The blood-brain barrier essentially acts as a trap."

Developing memory loss is cruel for people with Down syndrome, who already suffer a variety of learning and muscular disabilities, Rosenbloom said. The goal of the study is to prove that insulin can slow or prevent memory loss in patients with Down syndrome, though the findings could have implications for other diseases that cause dementia as well.

Trouble is, HealthPartners lacks study participants — specifically people with Down syndrome 35 years and older who are willing to receive the nasal insulin and then take part in memory challenges to see if the drug works.

Potential study participants or their relatives can call 651-254-7936 for more information. Rosenbloom said the goal is to prove the insulin is safe and effective, clearing the way for further studies and eventually federal approval for its use in Down syndrome.