Antiaging drug rapamycin might only benefit females, new research shows

Studies in fruit flies suggest women could age differently from men.

Researchers from University College London and the Max Planck Institute for Biology of Ageing in Cologne have discovered that the antiaging drug rapamycin prolongs the lifespan of female fruit flies – but not that of males. In addition, they found that rapamycin only slowed the development of age-related pathological changes in the gut in female flies.

Writing in Nature Aging, the researchers have drawn the conclusion that biological sex is a crucial factor in the effectiveness of antiaging drugs [1].

Longevity.Technology: The life expectancy of women is significantly higher than that of men, and this difference is thought to be due to a combination of biological, social and lifestyle factors. Some of the factors that may contribute to the higher lifespan of women include differences in genetics, hormones and immune function, as well as social and environmental factors such as access to healthcare and lifestyle choices.

However, women also suffer more often from age-related diseases and adverse drug reactions. Understanding how different drugs work in different sexes – and in different people – is part of the accelerating field of personalised medicine, an approach tailored to an individual, rather than what is best for a cohort. By taking into account each patient’s unique characteristics – such as their genes, sex, lifestyle and medical history – the most effective and targeted treatment can deployed, leading to better health outcomes and a higher quality of life for patients; not only that, but personalised medicine improves the efficiency of the healthcare system, helping to reduce the overall cost of healthcare and improve the allocation of medical resources.

“Our long-term goal is to make men live as long as women and also women as healthy as men in late life. But for that, we need to understand where the differences come from,” explains Yu-Xuan Lu, one of the leading authors of the study [2].

Rapamycin extends lifespan only in female flies

The researchers gave the antiaging drug rapamycin to male and female fruit flies to study the effect on the different sexes.

Rapamycin is a cell growth inhibitor and immune regulator that is normally used in cancer therapy and after organ transplantations, and the researchers found that rapamycin extended the lifespan and slowed age-related intestinal pathologies in female flies but not in males.

Healthier life due to more autophagy

The researchers observed that rapamycin increased autophagy – the cell’s waste disposal process – in the female intestinal cells. Male intestinal cells, however, already seem to have a high basal autophagy activity, which cannot be further increased by rapamycin.

The scientists could also see this effect of rapamycin in mice – female mice showed increased autophagy activity after treatment with rapamycin.

“Previous studies found that females had greater responses to rapamycin on lifespan extension than did males in mice, we now uncover an underlying mechanism of these differences using flies,” says Yu-Xuan Lu [2].

Sex-specific, personalised treatments

“Sex can be a decisive factor for the effectiveness of anti-ageing drugs,” explains Linda Partridge, senior author of the study.

“Understanding the processes that are sex-specific and determine response to therapeutics will improve the development of personalised treatments [2].”