A new, experimental drug significantly improves muscle endurance in mice. It is a finding that an international team of researchers hopes may some day benefit patients with conditions that limit exercise tolerance, including type 2 diabetes, which has become a global epidemic.
Although exercise could improve some chronic medical conditions, such as diabetes, obesity and congestive heart failure, those patients often lack the stamina to work out.
Now, researchers at the Scripps Research Institute in Jupiter, Florida and Institut Pasteur de Lille in France
have developed a promising experimental drug that dramatically increases the efficiency of muscles most responsible for endurance.
Thomas Burris, an expert in physiology and metabolism, helped developed the candidate drug, called SR9009, that was tested in mice. “Just treating them with the drug increases their ability to run for longer durations and longer times, in fact around 50 to 60 percent longer duration and distance,” he said.
In rodents lacking a molecule called Rev-erba, researchers saw an increase in fat storing cells and a decrease in metabolic activity in muscles responsible for burning fat.
But that changed when Rev-erba was switched on by SR9009.
In addition, Burris said, the drug decreased fat deposits in the blood and reduced cholesterol levels in the animals.
The compound also improved the absorption of glucose - sugar the body uses for fuel - by stimulating mitochondria, tiny structures inside cells sometimes called the body's power plants.
Burris said there is no guarantee the benefits of SR9009 seen in mice would occur in humans with metabolic syndrome, a precursor to type 2 diabetes marked by elevated levels of glucose, as well as cholesterol and blood fats known as triglycerides.
"But we do have indications that the effects of the drug are very similar to what you see with someone who has metabolic disorder who starts exercising," Burris stated. "They see a decrease in cholesterol, a decrease in triglycerides, an improvement in glucose metabolism. And a lot of this is due to transforming the muscle into a more metabolically active muscle."
An article describing improvements in muscle endurance in mice treated with the compound SR9009 is published in the journal Nature