13 July 2021

Live fast, die young: science

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How to live longer is a challenge that has preoccupied us probably since the dawn of humanity.

It has also been noticed along the way that women live longer than men, to an extent that can’t be explained simply by their tendency towards better self-care.

Now research has emerged that suggests a way to even things up, yet is unlikely to feature in anyone’s biohacking blog.

It seems the answer has been staring us, uh, in the face: ageing is directly linked to sex hormones.

Sheep research out of where else but New Zealand’s University of Otago, building on the observation that castrated males live longer than their intact fellows, has actually established the mechanism by looking at ovine epigenetics.

Authors of the study, published in elife, say that while there have been many hints linking sex hormones to ageing, from the longevity of castrated lab animals to the effects of menopause and ovariectomy,  “the effects of castration and/or testosterone production on the epigenetic predictors of aging in males have remained unknown in either humans or animal models prior to the current study”.

One particular inspiration for the study appears to have been a Merino named Shrek who lived for 17 years, and became famous for his shearer-avoidance and resulting enormous fleece – but we digress.

The team developed the first sheep epigenetic clock, a molecular biomarker for ageing, and compared regions of DNA methylation between castrated and non-castrated male sheep and female sheep.

The methylomes of castrated males showed slower epigenetic ageing and more resembled females’. Some of the regions associated with ageing were already known to be regulated by androgen receptor in humans and differ in their methylation patterns across sexes in various other mammal species.

“Taken together, these findings provide a credible mechanistic link between levels of sex hormones and sex-dependent ageing,” the authors write.

But put those shears down. Despite headlines like this, the scientists are not actually pitching this work as a practical piece of self-help for men who want to live longer.

If you spot some research that’s of no practical use to human medicine, but will make a great “fun fact” at your next social gathering, if you’re allowed those, tell felicity@medicalrepublic.com.au.

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