May 13, 2011
WASHINGTON (AFP) - A common blood pressure drug may also prevent muscle loss that comes with age and inactivity, US researchers said on Wednesday.
The promising results seen in mice have led researchers to begin organizing clinical trials in humans, said the study by scientists at Johns Hopkins University (JHU) published in the journal Science Translational Medicine.
Using 40 mice that at 21 months old were considered geriatric, researchers found that when they immobilized a leg muscle and treated the subjects with losartan, no muscle mass was lost after three weeks.
Mice who did not receive the drug lost 20 percent of their muscle mass in that time period.
"When we saw that the loss of muscle fibers was completely prevented by losartan therapy, it was quite mind-blowing," said Ronald Cohn, an assistant professor of pediatrics and neurology in the JHU McKusick-Nathans Institute of Genetic Medicine.
They also tested how mice recovered from muscle injury while using the drug.
After injecting a chemical toxin into a shin muscle and comparing results after 19 days, mice who took the drug had about 15-20 percent scar tissue compared to untreated mice who formed 30-40 percent.
Researchers said that if the findings can be replicated in humans, the drug could help prevent muscle loss that accompanies aging. People over 50 lose on average one to two percent of their muscle mass per year.
It could also help prevent atrophy that comes from injury, such as wearing a cast while a broken bone heals, or from prolonged inactivity such as in patients who are bedridden or astronauts who spend time in zero gravity.
"The goal of the investigation was to find a way to prevent a bad situation from getting worse in the case of old muscle that's injured or not used," said Cohn.
"As pleased as we were to see that losartan therapy in mice had a positive effect on muscle regeneration, we were most surprised and excited by its striking prevention of disuse atrophy."
