Rapamycin may exacerbate age-related arthritis despite life-extending benefits

In a new study, researchers from the University of Wisconsin-Madison explored the effects of rapamycin, metformin or a regimen of both medications on a guinea pig model of OA. These drugs were chosen because they have been shown to expand lifespan and healthspan through positive change in the mitochondria. The research team found that the animals treated with rapamycin and the two-drug combination had lower mitochondrial content in their muscles and the function of the mitochondria was impaired. In addition to changes in mitochondrial function, rapamycin treatment also led to a rise in blood glucose levels and worsened OA scores, a measure of disease severity.

These results suggest "there may be an indirect connection between impaired skeletal muscle mitochondrial function to exacerbated OA after rapamycin treatment," said Christian Elliehausen, first author of the study. More research is needed to examine if it is possible to "harness the positive effects of rapamycin while minimizing the negative effects," Elliehausen explained.