Intermittent rapamycin feeding recapitulates some effects of continuous treatment while maintaining lifespan extension

[Jonas]

A correction on the study re Glucose Intolerance:

[RapMet]

@RapamycinCurious

The two treatments had equivalent [harmful] effects on testicular degeneration, heart fibrosis and liver lipidosis [i.e., NAFLD]. … Liver lipidosis was increased in both intermittent and continuously fed males and females

If all these ill effects, how come study is showing increase in lifespan then? It is a bit contradictory as this would (at least in theory) mean that these mice were susceptible to other diseases (because of RAPA, yet somehow, they lived longer? Am I missing something?

[RapamycinCurious]

It just means that it reduces deaths from other causes that cause more deaths in mice. If you had a powerful preventive therapy for cancer and ASCVD in humans that simultaneously increased the risk of Parkinson’s disease, it would still increase survival in the general population.

[CronosTempi]

Also keep in mind healthspan does not map 1:1 with lifespan, similar how sexual fitness doesn’t map with lifespan in many species, generally effects such as antagonistic pleiotropy. Eunuchs live longer. Many such examples where you get greater lifespan at the cost of some impairment in function, especially reproductive.