Potential Therapeutic Strategy for Alzheimer’s Disease Based on Insulin

A study recently published in the Journal of Alzheimer’s Disease revealed that intranasal administration of insulin can be a potential therapeutic strategy for Alzheimer’s disease and dementia conditions. The study entitled “Central Nervous System Delivery of Intranasal Insulin: Mechanisms of Uptake and Effects on Cognition” was conducted by researchers at the University of Washington Medicine, Veteran’s Administration Puget Sound and Saint Louis University.

Alzheimer’s disease is a neurodegenerative disorder characterized by cognitive and behavioral problems. It is the most common form of dementia in the elderly with patients initially experiencing a memory loss and confusion that gradually leads to behavior and personality changes, a decline in cognitive abilities and ultimately to severe loss of mental function. Alzheimer’s disease is characterized by the loss of neurons responsible for memory and learning, and brain formation of amyloid plaques (containing sticky beta-amyloid proteins). It is estimated that 44 million people worldwide suffer from Alzheimer’s or other form of dementia.

Several studies have suggested that diabetes and insulin abnormalities can contribute to Alzheimer’s disease pathophysiology and clinical symptoms. In fact, intranasal insulin has shown efficacy in Alzheimer’s disease patients, although it is unclear whether and how insulin reaches the brain. In the study, researchers addressed these questions.

The team used a particular Alzheimer’s disease mouse model that is normal and healthy until it reaches “mouse middle age”, at 8 to 12 months, where it develops severe learning problems and memory issues. The team administered a single dose of intranasal insulin high up in the nasal cavity of these sick animals and found that it remarkably reversed their learning and memory deficits. Repeated doses were reported to increase the efficacy of insulin in mitigating memory loss. Furthermore, insulin was found to be distributed throughout the brain, poorly entering the bloodstream, and without peripheral metabolic effects. This observation is important as insulin could significantly lower blood sugar levels if it reached the bloodstream.

“Before this study, there was very little evidence of how insulin gets into the brain and where it goes,” said the study’s senior author Dr. William Banks in a news release. “We showed that insulin goes to areas where we hoped it would go. (…) This is one of those studies where everything is coming together,”

The research team concluded that insulin administration could be considered a potential therapeutic strategy for Alzheimer’s disease, with intranasal delivery proving to be a safe and effective method to administer insulin to the brain.

When discussing the possibility of a breakthrough in Alzheimer’s disease treatment, Dr. Banks compared the Alzheimer’s situation to HIV/AIDS as both called the attention around the 1980s, although the HIV/AIDS field received 10 times the funding of Alzheimer’s research, and while there is yet no cure, HIV/AIDS patients have lifesaving drugs available showing that medical research can indeed transform severe disorders into manageable conditions. “If we put similar resources into Alzheimer’s disease,” concluded Dr. Banks, “we could be equally effective.”