Aging muscle stem cells shift from rapid repair to long-term survival

There's some rather woo woo stuff out there about an evolutionarily conserved mechanism for intercellular signaling as a danger response which involves the mitochondria shifting their metabolism to help cells repel invaders, but which also interferes with the cells' normal activity. TLDR: if there's chronic inflammation cells go into this mode but never get the "all clear". Could this be the qi? Pun intended. It's just anecdata, haven't spent any time looking into it per se.

Stumbled onto this because I've been using TCM (in consultation with an herbalist) for blood pressure, relatively successfully, for a couple of years. Of course they didn't have blood pressure cuffs in the Ming or Han dynasties, so we're not really treating blood pressure... Researching astragalus and di huang is what led me to it.

Original article: "Cellular survivorship bias as a mechanistic driver of muscle stem cell aging" - https://www.science.org/doi/10.1126/science.ads9175

Abstract: "Aging is characterized by a decline in the ability of tissue repair and regeneration after injury. In skeletal muscle, this decline is largely driven by impaired function of muscle stem cells (MuSCs) to efficiently contribute to muscle regeneration. We uncovered a cause of this aging-associated dysfunction: a cellular survivorship bias that prioritizes stem cell persistence at the expense of functionality. With age, MuSCs increased expression of a tumor suppressor, N-myc down-regulated gene 1 (NDRG1), which, by suppressing the mammalian target of rapamycin (mTOR) pathway, increased their long-term survival potential but at the cost of their ability to promptly activate and contribute to muscle regeneration. This delayed muscle regeneration with age may result from a trade-off that favors long-term stem cell survival over immediate regenerative capacity."

This makes me wonder if that line "I only got so many heart beats, I'm not going to waste them running" has some validity

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I thought Satchel Paige said it, but apparently not. He did say "I generally don’t like running. I believe in training by rising gently up and down from the bench. "

Which also fits the "don't prematurely age the stem cells"

> Aging muscles heal more slowly after injury—a frustrating reality familiar to many older adults.

> In skeletal muscle, this decline is largely driven by impaired function of muscle stem cells (MuSCs)

I take it that as mitosis (cell division) gets slower with age, there's also simply no way aging muscles could potentially not heal more slowly?

So slower mitosis and then in addition to that muscle cells going into a "less repair, more survival" mode. Darn, sucks to get old.

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