Scientists have discovered a protein that could lead to the development of a medication that helps people lose weight. Science Magazine reports that researchers from three different pharmaceutical companies made the discovery and separately published their findings. They each identified the protein “growth differentiation factor-15” (GDF15), which has been said to cause a loss of appetite — medically described as anorexia — in those with late-stage cancer.
The protein targets parts of the brain where a receptor called GFRAL resides. There are only two regions where the GFRAL gene is expressed: the area postrema, also known as the “vomit-inducing center,” and the nucleus of the solitary tract, which contains the neurons involved in many behaviors related to the appetite.
Sebastian Beck Jorgensen, a diabetes and obesity researcher at Novo Nordisk in Maaloev, Denmark, and his team created a group of mice incapable of producing GFRAL, which would be compared to a group of regular mice. Both groups were fed a high fat diet for 16 weeks, leading to final weights of about 20-40 grams, before being injected with GDF15 for 4 weeks. The regular mice experienced a reduced food intake and managed to lose 5-10 grams; the mice without GFRAL receptor experienced no weight loss.
Research done by Eli Lilly & Company in Indianapolis, Indiana conducted a similar experiment with mice and observed similar results. Janssen BioTherapeutics in San Diego, California experimented on monkeys with a more powerful version of GDF15 that remained in the bloodstream for 4 week, resulting in a 4 percent drop in weight.
When the time comes to proceed to human trials, a stronger version made by Jorgensen and his team at Noro Nordisk will be used in combination with other forms of obesity treatment. The belief is that multiple treatments will be more effective than relying on any single one.
That said, there are some concerns about GDF15’s influence on the vomit-inducing center of the brain, despite the fact there were no signs of nausea or vomiting from the test monkeys. Of course, a monkey is unable to verbally explain how it feels, while a person easily could.
Despite the risks, further research and testing would be invaluable. In the U.S alone, nearly one-third of the population is considered to be obese, with over 112,000 death each year attributed to it. According to the World Health Organization, 13 percent of the global population was considered obese in 2014, and 39 percent overweight. If GDF15 is ever fully incorporated into medical treatments, it could save thousands of lives.
“Obesity is a complex disease with no one-size-fits-all treatment. Combination therapy is the future,” said W. Scott Butsch, a Massachusetts General Hospital obesity medicine physician not involved in the GDF15 research, to Science. “We’ve moved beyond thinking that one drug will win the jackpot and cure everyone’s obesity.”