Insulin delivered intranasally can improve gait and cognitive function in elderly patients with and without type 2 diabetes, according to a clinical trial conducted at Beth Israel Deaconess Medical Center (BIDMC). In fact, this finding could revolutionize the prevention of these age-related disorders. Initial data published in the Journal of Neurology are already consistent with the results of previous studies, warranting further testing.
An estimated 25% of people over 65 suffer from type 2 diabetes, a condition characterized by the body’s inability to produce enough insulin to effectively control blood sugar levels. Insulin is known to play an important role in the brain, and people with prediabetes and diabetes are at increased risk of Alzheimer’s disease and cognitive decline. Also, previous studies have shown that intranasal administration of insulin to the brain improves verbal memory.
Given the aging of the population and the increasing incidence of cognitive impairment, the question arises: With or without diabetes, is insulin beneficial for cognitive impairment?
The MemAID study
Initial data suggest that insulin is a possible treatment for cognitive impairment in the elderly. The Boston team evaluated the long-term effects of intranasal insulin (INI) on cognition and gait function in 223 participants aged 50 to 85 with or without type 2 diabetes. Scores on gait speed, attention, memory, executive function, and mood were included in the analysis using a battery of validated tests. In the study 50% of the participants had diabetes and the other 50% did not have it. Both groups were treated with insulin administered intranasally once daily. Some of the participants received an inactive placebo (sterile saline), which was also administered intranasally.
The randomized controlled phase 2 study confirmed that intranasal insulin in participants with type 2 diabetes:
- Increases walking speed
- Increases blood flow to the brain
- Decreases plasma insulin
In participants without diabetes:
- Improves decision-making and verbal memory
Taken together, these results suggest that intranasal insulin should be further tested for its effectiveness as a treatment for age-related cognitive and functional impairment.
“Gait speed is an important clinical predictor of well-being in the elderly, correlated with cognitive decline, risk of hospitalization, loss of independence, and death,” said lead author Vera Novak of the Department of Neurology at BIDMC and associate professor of neurology at Harvard Medical School. “At baseline, participants with diabetes walked more slowly and had more impaired cognition than participants without diabetes, which ‘served’ as a clinical benchmark for the normally aging population.”
This study offers hope for a new early intervention based on nasal insulin spray, a simple-to-administer treatment, to prevent or slow the progression of Alzheimer’s dementia, concludes the second lead author Dr. Long Ngo, co-director of the Division of Biostatistics of General Practice at BIDMC. The treatment did not result in serious or even moderate side effects.