Insulin given nasally shows promise for Alzheimer's, finds study
Patients with mild Alzheimer's disease might someday get help from a squirt of nasal insulin. Research suggests insulin, delivered nasally, provides brain cells with nourishment that might keep Alzheimer’s from progressing and even improve symptoms.
Insulin dysregulation, say the study authors, contributes to memory loss associated with Alzheimer's disease.
Though the findings are preliminary, scientists found insulin nasal spray stabilized or led to improvement in memory for patients with early Alzheimer's disease.
For the study, conducted by Suzanne Craft, Ph.D., of the Veterans Affairs Puget Sound Health Care System and the University of Washington School of Medicine, Seattle, and colleagues, researchers compared insulin nasal spray to placebo in 104 patients, divided into three groups.
One group received placebo; another 20 international units of an aerosolized nasal spray of insulin; the third group was given 40 international units a day. Dosing was twice a day.
The results of the four month pilot study, published in the Archives of Neurology, showed patients given the lower dose of insulin either had slight improvement in memory or remained stable. Patients given placebo got worse based on their ability to perform day-to-day functions and memory, cognition tests.
The improvement in Alzheimer’s symptoms may come from a boost insulin gives the brain for using glucose, which is necessary for normal brain function.
The scientists conducted brain scans in one-third of the participants. The placebo group had lower glucose uptake in the brain, compared to the group given insulin.
Conditions that affect insulin production are also linked to higher risk of Alzheimer’s disease, including diabetes and high blood pressure, leading the researchers to study the effect of the hormone for treating Alzheimer’s disease.
Giving insulin deep into the nasal cavity delivers the hormone to the brain via nerve pathways.
The researchers began their testing by giving one dose of insulin, finding patients had temporary improvement in memory. Next, they gave the drug daily, again finding it helped patient; leading to the current study.
According to Dr. Craft, the nasal insulin delivery system, manufactured by Kurve Technology, isn’t available to the public. The researchers hope to enroll patients, should the study go forward.
Researchers from Rhode Island Hospital and Brown Medical School found a link between insulin and Alzheimer’s disease in 2005.
Senior author Suzanne M. de la Monte, a neuropathologist at Rhode Island Hospital and a professor of pathology at Brown Medical School said the earlier finding raised the “possibility of Type 3 diabetes”.
Lower insulin in the brain leads to neurodegeneration, found in mouse studies. The finding was published in the Journal of Alzheimer’s Disease.
The current study is important, given the lack of treatment for Alzheimer’s disease.
The researchers note the improvement in Alzheimer’s symptoms seen in the study from giving nasal insulin may not be clinically significant and that larger clinical trials are needed before the insulin could be used as a treatment for Alzheimer’s disease.
Arch Neurol: doi:10.1001/archneurol.2011.233
"Intranasal Insulin Therapy for Alzheimer Disease and Amnestic Mild Cognitive Impairment"
Suzanne Craft, et al.
Sept 12, 2011
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