Intranasal insulin can help diabetics who develop dementia

by Barbara Hewitt on December 2, 2013

Older people with diabetes develop Alzheimer’s disease at an earlier age and are more likely to develop vascular dementia than people who do not have diabetes, according to a small pilot study from the United States.

While in recent years scientists have recognised the link between type 2 diabetes and dementia this new study led by researchers at the Beth Israel Deaconess Medical Center (BIDMC) in Boston says there is a new treatment.

brain diabetes

Intranasal administration delivers insulin directly to the brain, reaching receptors in multiple brain regions within minutes

The study results show that a single dose of intranasal insulin can help improve cognitive function in patients with diabetes.

‘We know that diabetes accelerates brain aging. If we consider that there are more than 45 million people with diabetes in the US alone and that older adults are the fastest growing segment of the diabetes population, we realize what an extremely serious problem we’re facing,’ said author Dr Vera Novak, an investigator in the Department of Neurology at BIDMC.

She explained that in the brain, insulin helps to regulate signalling and connections among neurons and also regulates vascular functions. Central insulin receptors are abundant and yet are mostly dependent upon insulin transport through the blood brain barrier. Therefore, inadequate insulin delivery may affect perfusion and cortical activity in brain regions associated with high energy demands, such as cognitive networks.

‘Previous studies had suggested that augmenting cerebral insulin may enhance cognitive function,’ said Novak, who is also an Associate Professor of Neurology at Harvard Medical School.

She pointed out that intranasal administration delivers insulin directly to the brain, bypassing the blood brain barrier and reaching receptors in multiple brain regions within minutes after administration.

In this pilot study, the authors tested whether similar effects would be observed in patients with diabetes. Some 15 patients with diabetes and 14 healthy older adults, average age 62, were administered a single 40 unit dose of insulin or saline in a randomised order on two subsequent days. Measurements of brain function were then made using regional perfusion and vasodilatation with 3 Tesla MRI and neuropsychological evaluation of learning and memory.

‘We observed in both the healthy subjects and the patients with diabetes that there was an improvement in both verbal learning and visual spatial learning and memory after they received the insulin,’ said Novak.

Through imaging tests, the research investigators also learned that these improvements were dependent on the brain’s vascular function. ‘Our findings provide preliminary evidence that intranasal insulin administration appears safe in older adults, and does not lead to low sugar levels,’ explained Novak.

‘Intranasal insulin may potentially improve learning and memory in older adults with and without diabetes, through vascular mechanisms. However, larger and longer duration studies are needed to determine whether intranasal insulin may provide long term benefits for memory in older patients with diabetes,’ she concluded.


The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

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