Scientists Engineer Proteins That Caused Obese Animals to Lose

Source: latimes.com

The U.S. obesity rate has galloped toward 40%, doctors, drug designers and dispirited dieters have all wondered the same thing: What if a pill could deliver the benefits of weight-loss surgery, but without the knife?

Scientists from the biotechnology company Amgen Inc. report they have identified and improved upon a naturally occurring protein that brought about significant changes in obese mice and monkeys, including weight loss and rapid improvements on measures of metabolic and heart health.

In mice who got a bioengineered version of the GDF15 protein, the researchers observed remarkable changes. These obese mice turned their noses up at extra-rich condensed milk — a treat that normally prompts mice to gorge themselves. 

Given the choice, the treated mice tended to opt for standard mouse chow instead, or at least lowered their intake of the fattening condensed milk.

The natural version of the GDF15 protein breaks down quickly in the blood. To be an effective weight-loss aid, it would need more staying power.

The Amgen researchers accomplished this by fusing the protein with other agents that would not break down so quickly. The two engineered versions of GDF15 remain biologically active in the blood for longer.

In the brains of the lab animals that received the treatment, the study authors detected activation in a population of brain-stem cells that transmits complex signals between the brain and gut.

In obese people, those signals — which urge us to eat when we’re hungry and to stop once we’ve eaten — become faulty, causing us to overeat and gain weight.

“This is a new system” involved in the regulation of appetite, said Dr. Ken Fujioka, a weight-loss specialist at Scripps Clinic Del Mar. “It’s not one we’ve seen before, and that’s a big deal.”