Could a sniff of insulin preserve memory?

A new study has found that the use of intranasal insulin produced an improvement in memory and cognitive function in a small group of people with either amnesic cognitive impairment or mild to moderate Alzheimer’s disease.

The role of insulin in Alzheimer’s has been extensively investigated. In the brain, abnormalities of insulin levels and activity have been known to be associated with the pathophysiology of Alzheimer’s. Type two diabetes (where a person has abnormal resistance to insulin) is a recognised risk factor for Alzheimer’s disease.

Having a normal blood sugar is important for our normal thinking skills and memory. I’m sure many of us recognise how we don’t think so well either when we are really hungry when our blood sugar levels are really low, or conversely when we get that sugar high after eating a high sugar snack. The sugar fix is the signal for our body to release the hormone insulin which then restores our blood sugar to normal.

Using the insulin intranasally allowed the researchers to supply the brain with an extra shot of insulin, without producing any peripheral effect on blood sugar levels. This was important as the symptoms associated with having too low a blood sugar are not insignificant and include dizziness, confusion, heart palpitations, feeling anxious and altered vision.

In the study the intranasal insulin was administered over a 4 month period. One hundred and four subjects received either a 20 IU or 40IU dose of insulin or a placebo saline spray daily. Those given the 20 IU insulin dose showed an improvement in memory that wasn’t apparent with the higher dose and both groups showed less decline in cognitive skills compared to the control group. There was also an improvement in functional ability for example in being able to handle money in those with Alzheimer’s who received the insulin spray.

This is a fabulous early study, which is now being followed up to involve a larger group of people over a longer period of time.

But the key for managing early Alzheimer’s disease, still remains in having an early diagnosis. This remains elusive for the present.

Intranasal treatments for delivery medication directly to the brain are not new. Earlier this year I blogged about how one research team have been investigating the use if intranasal Viagra as a means of preventing Alzheimer’s and stroke.

Ref: Suzanne Craft; Laura D. Baker; Thomas J. Montine; Satoshi Minoshima; G. Stennis Watson; Amy Claxton; Matthew Arbuckle; Maureen Callaghan; Elaine Tsai; Stephen R. Plymate; Pattie S. Green; James Leverenz; Donna Cross; Brooke Gerton. Intranasal Insulin Therapy for Alzheimer Disease and Amnestic Mild Cognitive Impairment: A Pilot Clinical Trial. Archives of Neurology, 2011; DOI: 10.1001/archneurol.2011.233