Ruxolitinib, a drug that targets cell aging pathways, significantly improved muscle and bone health and extended lifespan in a mouse model of severe Duchenne muscular dystrophy (DMD), according to a study published recently in Pharmacological Research.
These results suggest a potential new direction for treatment. When paired with the corticosteroid deflazacort (which is commonly used in DMD), the two drugs worked together to further restore bone strength and muscle integrity.
“This study provides new insights on the application of senolytic pharmaceuticals to treat DMD patients by protecting both bone microarchitecture and improving muscle pathology,” explained this study’s authors.
This study focused on “dKO-Hom” mice that lack both dystrophin and utrophin, proteins essential for muscle structure. These mice mirror an extreme form of DMD. Researchers found that their skeletal muscles contained large numbers of “senescent” macrophages, which are immune cells that had stopped dividing but release inflammatory molecules.
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Treatment with ruxolitinib for 12 days decreased the number of these senescent macrophages and lowered inflammation in skeletal and heart muscle. The drug also reduced muscle damage and promoted the appearance of new muscle fibers. Mice receiving ruxolitinib lived significantly longer than untreated mice, gained muscle strength and performed better on endurance tests. Bone imaging showed thicker, denser trabecular bone in the spine and tibia, reflecting improved bone microarchitecture.
Deflazacort, a standard DMD therapy, already helps slow muscle breakdown, but long-term use can weaken bones. When ruxolitinib and deflazacort were given together, bone quality improved more than with either drug alone, suggesting a synergistic effect. The combination also led to lower inflammation, healthier heart tissue and greater muscle regeneration.
In contrast, other drugs that target cell aging, such as fisetin and the dasatinib-quercetin combination, did not improve muscle or bone outcomes in these mice, highlighting ruxolitinib’s unique benefit.
For patients, these findings raise cautious optimism. If ruxolitinib produces similar effects in humans, it could complement deflazacort to reduce inflammation, preserve strength and protect bone health. The results underscore the potential of targeting cellular senescence as a therapeutic strategy in DMD, though clinical studies will be needed to confirm safety and effectiveness in people.
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