Researchers at Washington University School of Medicine have found that stimulating a protein in muscle tissue can increase the average lifespan of mice and also foil some age-related diseases.
The researchers believe a similar approach may someday help people avoid age-related problems such as atherosclerosis, diabetes, hypertension and even some cancers.
The study was conducted through a series of experiment where the researchers bred large numbers of mice, fed them a normal chow diet and followed each mouse until its natural death.
Half were genetically engineered to make more of a protein in their muscle tissue called uncoupling protein-1.
The uncoupling protein-1 converts the energy from food into heat and imitates the effects of exercise.
In a past research conducted in the laboratory of Clay F. Semenkovich, the Herbert S. Gasser Professor and chief of the Division of Endocrinology, Metabolism and Lipid Research, it was found that mice with extra uncoupling protein-1 in muscle tissue are protected from diabetes and obesity.
"Uncoupling basically means generating inefficient metabolism," said Semenkovich.
"We knew years ago that when mice manufactured uncoupling protein in muscle, they didn't become obese. The next challenge was to see whether the protein would be relevant to some of the major problems that affect humans, namely aging and age-related disease," he added.
Semenkovich said that he was disappointed when maximum didn't increase.
"We were a little bit disappointed because we had hoped uncoupling in muscle would slow aging, but maximum lifespan didn't increase. However, the odds of reaching that maximum lifespan did improve in the uncoupled mice," he said.
The results revealed that the mice with the genetic modifications were more likely to live longer, presumably because they were able to avoid age-related diseases.
A common feature in all experiments was that the body fat decreased along with inflammation in the animals by accelerating muscle metabolism with uncoupling protein delayed death and diseases, including atherosclerosis, diabetes, hypertension and even cancer.
"Where the uncoupling occurs has a big impact," he says. "If this principle someday becomes a therapy, it will be very important to target the proper tissues to produce the desired effects," said Semenkovich.
"Uncoupling in muscle may be a substitute for exercise," he says. "If that's true in humans, and if uncoupling can be done safely, this could be an important therapy because it's sometimes very difficult to get people to exercise," he concluded.