Leptin, a hormone that plays a key role in regulating energy intake and expenditure in the body, may be an alternative to insulin for diabetics, new research suggests.
Researchers from Texas, California, Harvard and Geneva looked at mice that were genetically engineered not to produce any insulin and tested one group with injections of leptin whilst the other group had no treatment.The research found that the untreated mice died, as expected, whereas the mice treated with leptin survived and the research then looked at how leptin was able to help.
Leptin is a hormone secreted by fat cells and is known to regulate fat storage and usage as well as appetite. The study investigated how it was able to help the mice treated with the hormone to survive and found that it allowed them to have more normal blood sugar levels.
It found that leptin, primarily known for its slimming effects, actually lowers blood sugar levels by acting on neurons in the hypothalamus portion of the brain that regulate blood glucose. They said that they were surprised to find that leptin’s action was being mediated by specific nerves.
Dr. Teppei Fujikawa of the University of Texas Southwestern Medical Centre, first author of this paper, said that with this knowledge researchers can now look for ways to apply it to people and pave the way for developing better treatments.
The traditional understanding has been that people with diabetes that make very little of their own insulin must rely on taking exogenous insulin, that is taking insulin from outside of the body such as by injection or the use of insulin pumps.
The use of injections or insulin pumps has become a part of daily life for people with type 1 diabetes and also for a significant number of people with type 2 diabetes. A major problem associated with insulin therapy is an increased susceptibility to experiencing very low blood glucose levels, known as severe hypoglycemia, which can affect quality of life and can lead to coma or death in worst cases.
With leptin, there is no equivalent risk of developing severe hypos and the researchers are confident that leptin could perform a similar role in humans and could therefore represent an alternative treatment for people with diabetes that would otherwise be insulin dependent.
‘Through this discovery, the path to offering an alternative to insulin treatment is emerging. Now we need to understand the mechanisms through which leptin affects glucose level, regardless of insulin level,’ said Roberto Coppari who led the team at the University of Geneva.
He added that it means that scientists are now considering alternatives to insulin treatment which poses many risks to patients. For example, about 90% of patients over 55 who have been undergoing treatment for several years develop cardiovascular disease due to elevated levels of cholesterol brought on by the lipogenic properties of insulin.