Increasing Leptin Hormone Reverses Type 2 Diabetes

By employing a new gene therapy technique that increased the production of the appetite-controlling hormone leptin, researchers were able to reverse type 2 diabetes in mice, according to a new study published in the September 2006 online edition of Peptides.

A gene embedded in a harmless virus was injected into the brains of the mice to increase leptin production in the hypothalamus, which regulates this hormone. Although past studies showed that leptin acts to regulate weight and appetite, this is the first time leptin has been shown to independently affect insulin secretion as well.

"We found that we were successful in keeping the blood levels of insulin low and at the same time keeping blood glucose levels at a normal range,” said senior author Satya Kalra, Ph.D., a professor of neuroscience at the University of Florida (Gainesville, USA). "In other words, we were able to correct diabetes in these animals under various challenges.”

Eating rich and fatty foods causes blood sugar levels to rise, which in turn causes the body to produce more insulin, a protein that helps the body use carbohydrates. Patients with type 2 diabetes often become resistant to the insulin they make, causing much of it to build up in the body. After gene therapy, tests revealed that the blood sugar and insulin levels in the mice that received the therapy had returned to normal, even when they were fed a high-fat diet. However, mice that ate a high-fat diet but did not receive gene therapy continued to overproduce insulin and have high blood sugar levels, which are markers for type 2 diabetes. In another arm of the current study, the researchers discovered that normal, nondiabetic rats that received leptin gene therapy also produced lower levels of insulin.

Apart from keeping blood sugar and insulin levels low, the gene therapy also enabled the rodents to live longer than other obese rodents. "Currently, we do not know if that is due to the correction of the diabetes or many of the diseases associated with diabetes,” said Dr. Kalra. "It is clinically known that diabetic patients have early onset mortality. If the diabetes is managed, there is an improvement in lifeplan.”



Related Links:
University of Florida