You may have recently seen articles about the protein responsible for exercise's physical benefits, a study that found that having sex less frequently was linked to earlier menopause, and a new machine that keeps human livers alive outside of the body for transplant. Here's why you didn't see them on Medscape Medical News.
"A replacement for exercise?" the press release headline teases. Alas, like many questions asked in headlines, the answer appears to be "no." In a study published in Nature Communications, scientists probed the role of the Sestrin family of proteins in mediating the positive physiologic effects of exercise. They found that both fruit flies and mice that were deprived of the protein didn't build endurance as they exercised. When the researchers boosted the Sestrin protein in flies' muscles (they didn't try in mice), their performance improved without exercise.
"Sestrin may serve as a promising therapeutic molecule for obtaining exercise-like benefits such as improving mobility and metabolism," the authors concluded, but that's as close as they got to a treatment to replace exercise. Any attempt to develop a drug from Sestrin is still more or less at the starting line, far from clinical relevance. We didn't think this basic research, however important as a contribution to the existing body of work on Sestrin, needed our readers' attention.
Sexual Frequency Linked to Age of Menopause
Inspired by previous research that showed that married women experienced menopause later in life than unmarried women, researchers in the Department of Anthropology at University College London ran a study to test different hypotheses of why that might be. They did not replicate the finding that relationship status affects women's age at menopause, but they did report finding a link between women's frequency of sexual activity and whether they began menopause.
The authors acknowledge that their study's design did not allow them to draw conclusions about causality, but they also write, "we did demonstrate that increased sexual frequency during the pre- and peri-menopause decreased the risk of experiencing menopause." It's hard to know what to make of the results of this study, especially without a clear sense of the biological mechanism for the relationship the authors propose between sexual frequency and age at menopause. The research also doesn't offer actionable information for clinicians to give to patients, so we skipped it.
Stayin' Alive, Liver Edition
Researchers at ETH Zurich and the University of Zurich in Switzerland have developed a machine that can preserve donated livers alive outside of the body. They described their experiments to develop and test the machine in an article in Nature Biotechnology. The researchers reported that of 10 human livers they tested on the machine, six maintained their structure and that function was preserved after 7 days of perfusion.
Developing new technology to solve medical problems as important as the shortage of organs for transplant is fascinating and critical. But given how early-stage this particular piece of technology is ― they didn't try to transplant the livers ― we didn't think our clinical readers needed to know about it just yet.
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Cite this: The Week That Wasn't: Exercise Pill, Sex to Delay Menopause, Preserving Livers - Medscape - Jan 17, 2020.