Researchers at Oregon State University have found that directly delivering leptin to the brain through gene therapy may support healthy weight loss.

“A long, long time ago leptin was discovered. A scientist fed rats leptin and discovered that the rats that consumed high doses of leptin had less fat. We thought that this would be the cure for obesity, but when people consumed leptin, not much happened,” said Urszula Iwaniec, associate professor in the College of Pacific Health and Human Sciences at OSU.

According to Iwaniec, there are multiple reasons as to why leptin did not work in humans when consumed orally.

“This could have been because of the blood brain barrier, or because it was saturated, or because it had a down regulated response,” said Iwaniec.

Researchers found that the blood brain barrier stopped the leptin from working. This leads to the hypothesis that if leptin is directly injected into the brain, it wouldn’t have to go through the blood brain barrier, and it would cause weight loss as intended. Though it did not work on everyone, it did work on those who were morbidly obese.

“Leptin works beautifully in people who are morbidly obese. A small amount of people aren’t able to make leptin, and it works beautifully in them,” said Russell Turner, a professor in the College of Public Health and Human Sciences at OSU.

Although leptin works successfully in people who are morbidly obese, it does not work on those whose bodies do make leptin, and who are somewhat obese.

“It does work on people who are morbidly obese, but it is not something that can solve obesity in the general public,” Iwaniec said.

Leptin has only been tested on animals up to this point as researchers continue to study the side effects, dangers and other unanswered questions. Leptin appears to be working incredibly well.

“If it works in people as good as it works in animals, then it will be great. The animals do not have any food restrictions; they are on a normal diet, and abdominal fat was reduced. Because the animals are on a normal, healthy diet, but are just overeating, we don’t know what will occur in people who have a bad diet,” Turner said.

As shown in animals, leptin is especially helpful in weight loss with age.

“The rats have a healthy weight gain as they get older, but leptin has proved to aid this weight loss and reduce abdominal fat,” Turner said.

According to the research, the use of leptin for weight loss is better than dieting and will eliminate the negative side effects of weight loss.

“When people lose weight, they lose more than fat. There are side effects and most times when people lose weight, they gain it back, and then they will lose weight, and then they will gain it back, which can cause osteoporosis, and leptin can avoid this. And there is normally rapid bone loss with the weight loss, but we aren’t seeing that,” Turner said.

Although the weight loss impressed researchers, the side effects of weight loss, such as bone loss, are a main focus of the study. “We are interested from a bone perspective. If you yo-yo diet, you don’t gain the bone that you lost, back,” Iwaniec said.

Though extensive, the surgery and the injection is a one-time occurrence.

“The injection randomly goes into cells, so we can’t control where it goes, but one injection is good for most of the life of the animal,” Iwaniec said.