Results of a pilot clinical trial show a nasal-spray form of insulin delayed memory loss and preserved cognition in people with cognitive deficits that range from mild cognitive impairment (MCI) to moderate Alzheimer’s disease.
A team led by Suzanne Craft, PhD, at the Veterans Affairs Puget Sound Health Care System in Seattle led the trial, which was sponsored in large part by the National Institute on Aging (NIA), part of the National Institutes of Health. Importantly:
• Previous research suggests that insulin abnormalities contribute to Alzheimer’s pathophysiology.
• Researchers suspected that restoring normal insulin function in the brain may provide cognitive benefit and slow disease progression.
• A nasal spray delivers insulin quickly and directly to the brain - and does not result in harmful side effects, such as increased insulin levels in the rest of the body.
The trial included 104 adults with either “amnestic MCI” - in which people have memory loss and may progress to Alzheimer’s - and those with mild to moderate Alzheimer’s disease dementia.
The trial participants received either: 20 IU (international units) of insulin; 40 IU of insulin; or a saline placebo, all administered through a nasal drug delivery device for 4 months.
Memory, cognition and functional ability were measured before and after treatment. A subset of participants also received lumbar punctures to test cerebrospinal fluid and brain scans before and after treatment.
As outlined in the researchers’ report,* published online Sep 12 by the AMA's Archives of Neurology, "Treatment with 20 IU of intranasal insulin improved memory - and both doses of insulin preserved general cognition and functional ability."
These results point out the need for larger trials of insulin nasal-spray therapy to further test its effectiveness in treating Alzheimer’s disease.
* Free full-text article: “Intranasal Insulin Therapy for Alzheimer Disease and Amnestic Mild Cognitive Impairment: A Pilot Clinical Trial” Craft S, et al. Archives of Neurology. Online Sep 12, 2011.
Source: National Institute on Aging news release, Sep 12, 2011