Could an insulin nasal spray help treat Alzheimer's?

Every 67 seconds, someone in the USA develops Alzheimer's disease. More than 5 million Americans are living with the condition and it is responsible for around half a million deaths each year. 

But in a new study, researchers from the Wake Forest Baptist Medical Center in Winston-Salem, NC, reveal they may have found a promising new treatment for the disease - in the form of an insulin nasal spray.

Insulin detemir could offer a promising new treatment for patients with Alzheimer's or MCI, according to the study.

The researchers at Wake Forest, found the spray may also be effective for patients with mild cognitive impairment (MCI), which is estimated to affect around 10-20% of people over the age of 65.

In September 2011, on another study by the same researchers, they revealed that an insulin nasal spray improved memory among patients with Alzheimer's and other forms of cognitive impairment.

In that study, participants received 20 or 40 international units (IU) of insulin via a nasal drug delivery device. In this latest study, however, the team used the same device to deliver 20 or 40 IU of insulin detemir - a manufactured form of insulin that provides longer-lasting effects, compared with "regular" insulin.

Working memory improved for patients with MCI, Alzheimer's

Each day for 21 days, 60 adults who had been diagnosed with MCI or mild to moderate Alzheimer's disease received either 20 IU of a placebo, or 20 or 40 IU of insulin detemir - all of which were administered nasally.

The study findings - published in the Journal of Alzheimer's Disease - revealed that participants who received 40 IU of insulin detemir showed major improvement in their working memory - the ability to retain and process new information - compared with participants who received 20 IU of insulin detemir or the placebo.

What is more, participants who received 40 IU of insulin detemir and who possessed APOE-e4 - a gene associated with increased risk of Alzheimer's - displayed higher scores on memory tests than participants who received the lower insulin detemir dose or the placebo.

Participants who did not have the APOE-e4 gene had lower memory scores, regardless of whether they received a 20 or 40 IU dose of insulin detemir or the placebo.

On assessing the safety of the insulin detemir spray among participants, they found it only triggered minor side effects.

Commenting on their findings the research team says:

"The study provides preliminary evidence that insulin detemir can provide effective treatment for people diagnosed with MCI and Alzheimer's-related dementia, similar to our previous work with regular insulin.

We are also especially encouraged that we were able to improve memory for adults with MCI who have the APOE-e4 gene, as these patients are notoriously resistant to other therapies and interventions."

The research team says further research is needed to investigate the mechanisms that underly the association between insulin detemir administration and improved memory among people with the APOE-e4 gene.

In addition, the researchers say future studies should further assess the "safety and efficacy of this promising treatment."

References:

1.  Long-acting intranasal insulin detemir improves cognition for adults with mild cognitive impairment or early-stage Alzheimer's disease dementia, Suzanne Craft, et al., Journal of Alzheimer's Disease, DOI: 10.3233/JAD-141791, published online 5 November 2014, abstract.
2.  Wake Forest Baptist Medical Center news release, accessed 9 January 2015 via EurekAlert.
3.  Additional source: Alzheimer's Association, Alzheimer's facts & figures, accessed 9 January 2015.