Calorie Restriction and mTOR Inhibition are Additive in Slowing Muscle Loss with Age

It is intriguing to see that calorie restriction and mTOR inhibition are additive when it comes to slowing the age-related loss of muscle mass and strength, the path to sarcopenia. Both interventions are thought to influence long-term health largely through upregulation of autophagy, but calorie restriction produces very broad, sweeping changes in metabolism. The downstream changes due to mTOR inhibition only touch on a fraction of those. Thus this result may in time lead to a better understanding of which mechanisms are important in the way in which the operation of metabolism determines the pace of aging. Still, we know the scope of the benefits produced by calorie restriction in our species, and it is nowhere near as influential on life span as it is in mice. This part of the field is unlikely a path to significant gains in human longevity.

We now live longer than at any point in human history, but to enjoy those extra years, we need to remain healthy, mobile and independent. With age, however, our muscles inevitably lose mass and strength. "Age-related muscle decline already occurs in our thirties but begins to accelerate at around 60. By age 80, we have lost about a third of our muscle mass. Although this aging process cannot be stopped, it is possible to slow it down or counteract it, for example through exercise."

Researchers have demonstrated in mice that both calorie restriction and the drug rapamycin have a positive effect on aging skeletal muscle. It was thought that moderate fasting and rapamycin represent different means of achieving the same goal, namely suppression of the protein complex mTORC1, which accelerates aging when overactive. "Contrary to our expectations, however, the treatments do not redundantly converge at mTORC1. While we could understand that calorie restriction would have beneficial effects beyond mTORC1 suppression, it was incredibly surprising to us that rapamycin, an mTORC1 inhibitor, further slowed muscle aging in calorie restricted mice, where mTORC1-activating nutrients are available for just a few hours each day."

In calorie-restricted mice treated with rapamycin, the beneficial effects were therefore additive, with mice displaying significantly better muscle function than mice receiving either treatment alone. The positive impact of calorie-restricted diets and rapamycin on muscle aging leads to the intriguing question of whether elderly people suffering from sarcopenia can profit from a combined therapy consisting of an mTORC1 inhibitor, a calorie restriction-mimicking drug, and perhaps exercise.




Scientists rejuvenated the skin of a 53-year-old woman to that of a 23-year-old's in a groundbreaking experiment

The BBC reported German molecular biologist Wolf Reik, postdoctoral student Diljeet Gill, and a team at Babraham Institute built upon Yamanaka's work. Yamanaka grew stem cells by exposing adult cells to four molecules for about 50 days - a unique method he named iPS. Reik and Gill's team exposed skin cells to the same molecules for only 13 days, then let them grow under natural conditions.

Posted by: Person1234 at April 26th, 2022 1:18 PM

@Person 1234. There's a pretty comprehensive set of posts on partial reprogramming if you scroll down the page...

Posted by: Fitzy at April 26th, 2022 2:14 PM
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