Obesity Cure? Scientists Discover Antibody That Reduces Body Fat in Mice

A treatment for obesity could be on the horizon as scientists have discovered an antibody that reduces body fat.

In trials on mice, the antibody was found to increase bone mass and reduce adipose tissue (fat)—and while human studies are some way off, the findings could lead to new treatments for weight loss and osteoporosis.

The antibody discovered targets follicle-stimulating hormone (FSH) found in the pituitary gland. Ten years ago, scientists started looking at the hormones made in the pituitary gland to see how they act on certain targets. They found some of these hormones had an effect on bone mass.

From this, they created an antibody to see if it could be used to prevent bone loss in mice—and in 2010, they showed it could. As a result, they started considering it as a potential treatment for osteoporosis, particularly in post-menopausal women—a period when women lose bone mass fairly quickly.

But scientists also realized it could have other uses. Mone Zaidi, from the Icahn School of Medicine at Mount Sinai, New York, is one of the authors on the latest study into how the antibody triggers weight loss. "Osteoporosis and obesity are fairly closely linked in several ways," he tells Newsweek. "Women, when they undergo menopause, lose bone and gain body fat. So we thought maybe there was a connection—that FSH could have direct effects on adipose tissue."

In the study, published in Nature, scientists injected the antibody into mice that had had their ovaries removed (mimicking menopause) and mice that had been fed on a high-fat diet. In both cases, the antibody caused significant weight loss and gains in bone mass.

Zaidi says they looked at the adipose tissue in different areas of the body, including under the skin and around the vital organs. "In all compartments it was [fat] reduced by around this level. It's a fairly dramatic effect." Mice also showed increased oxygen consumption, higher levels of physical activity and more heat production in beige fat (which dissipates energy around the body).

But how do mice models translate to human treatments? Mice a fairly close genetic match to Humans, and Zaidi is hopeful there will be similar effects in humans.

Their next step is to "humanize" the antibody, so it can be tested without triggering an immune response. "We would then hopefully go to the next phase of preclinical testing, which would be to look at side effects, toxicology etc. After that, we would go into primates and larger animals. That would then lead—if all goes well—to the first human trials in three to four years."

At present, the researchers are focusing on the adiposity, rather than bone loss, for drug development: "I think obesity is a more prevalent disease—but osteoporosis at the tail end can be tagged on. Also to do trials for osteoporosis takes a very long time," Zaidi says.

Eventually, he hopes to end up with an injected drug that gets rid of fat and increases bone mass. "That's the ideal situation," he says. "It could be a unique obesity drug. But it could also be a unique drug because it lowers body fat and makes bones stronger. And the population that could be most benefited by this could be post-menopausal women."

Commenting on the research, Tim Speckor, Professor of Genetic Epidemiology at King's College London, U.K., says: "It's a nice mouse study that seems to work—whether it works in humans is another matter."