Blood Pressure Drug Helps Regenerate Muscle, Prevent Atrophy

(National Institutes of Health)

Medical researchers at Johns Hopkins University in Baltimore, Maryland have found the blood pressure drug losartan can help repair injured muscle and protect against muscles wasting away, at least in mice. Their findings appear in this week’s issue of the journal Science Translational Medicine (paid subscription required).

Previous research revealed that as humans age, the activity of a protein secreted by cells — called transforming growth factor beta (TGF-b) — increases, and that more TGF-b translates into less muscle repair. Other studies have shown how losartan promotes muscle regeneration in mice with muscular disorders by blocking a protein receptor and reducing TGF-b activity.

The Johns Hopkins researchers, led by pediatrics and neurology professor Ronald Cohn, treated half a sample of geriatric mice — at least 21 months old — with losartan and later injected the entire sample with a chemical toxin into the shin muscles of the mice. The treated sample after 19 days had lower percentages of scar tissue on the affected muscles than the non-treated group. However, neither group showed evidence of new muscle formation — small fibers with larger than usual nuclei.

To test the impact of losartan on inactive muscles, the researchers again treated half a sample of geriatric mice with the drug and half without. This time, they team bound the hind right foot of each mouse to its leg, immobilizing the shin muscles.

After 21 days, the researchers weighed the animals’ shin muscles and compared them under a microscope. The animals not treated with losartan lost 20 percent of the mass of their immobilized shin muscles, while the losartan-treated animals lost virtually no muscle mass.

The research has implications for potential treatments of muscle loss and weakness during aging, condition known as sarcopenia, which like bone loss can lead to frailty and disability. “When we saw that the loss of muscle fibers was completely prevented by losartan therapy, it was quite mind-blowing,” Cohn says.

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