There is now some hope for the 5.4 million people suffering from Alzheimer’s, the sixth-leading cause of death in the United States. A new study suggests that a nasal insulin spray may have therapeutic benefits for adults suffering from Alzheimer’s or a related illness.
Over a four-month period, 104 adult participants with amnestic mild cognitive impairment or mild to moderate Alzheimer’s were administered a nasal drug device containing certain doses of insulin or a placebo. Thirty participants received the placebo, 36 received 20 international units (IU) of insulin, and 38 received a 40 IU dose of insulin.
Insulin, a hormone secreted by the pancreas to use and store glucose, also plays a large role in the central nervous system. Brain insulin receptors in the hippocampus (the body’s center of memory) and other brain regions allow for optimal memory. However, insulin levels and activity in the central nervous system are reduced when one suffers from Alzheimer’s.
Researchers measured results based on delayed story recall—or how well a participant could recall a story containing 44 bits of information immediately after the story was told and then 20 minutes later—and a Dementia Severity Rating Scale (DSRS) questionnaire completed by a study partner, who rated the participant’s cognitive, social, and functional ability over a specific period of time.
The study found that those treated with 20 IU of insulin improved both in delayed story recall (or memory) and in the DSRS survey. But in the group that took 40 IUs of insulin, there was no improvement in the story recall study, but there was improvement in the DSRS questionnaire.
A secondary measure found that the two groups that took insulin had less decline in cognition compared with the placebo group, based on the Alzheimer Disease’s Assessment Scale (ADAS).
The results released in the September 2012 issue of the Archives of Neurology are promising for the estimated 5.4 million Americans who have Alzheimer’s or similar dementias, as well as the 15 million people who are providing more than $202 billion worth of unpaid care to help their relatives or friends.
However, it should be noted that due to the brevity of the clinical trial, the long-term impact of the nasal spray is still unclear. In addition, researchers say administering insulin the same way diabetes patients do will not produce the same results as a nasal spray and doctor’s don’t recommend it. The practice of administering diabetes-style doses of insulin to non-diabetics is actually very dangerous, since it can increase the risk of hypoglycemia. Insulin nasal spray allows a quicker delivery of the hormone to the central nervous system without affecting blood insulin or glucose levels.
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