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. Researchers at the Veterans Affairs Puget Sound Health Care System in Seattle led the trial, which was supported in large part by the NIA.
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 delivered insulin quickly and directly to the brain and does not result in harmful side effects, such as increased peripheral insulin levels.
The trial included 104 adults with either amnestic MCI or mild to moderate Alzheimer’s disease dementia. They received 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.
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.
Reference: Craft S, et al. Intranasal insulin therapy for Alzheimer disease and amnestic mild cognitive impairment: a pilot clinical trial. Archives of Neurology. 2012 Jan;69(1):29-38. Epub 2011 Sep 12.