Even if the original SnCs are eventually eliminated (which isn’t entirely clear), it sure looks like they should increase the SnC baseline anyway. It’s not just background processes that can produce new SnCs, but SnCs themselves produce new, secondary SnCs too. So, it’s not unlikely that adding a bunch of SnCs to the baseline pool of SnCs (whose size increases with age) could further increase the size of this pool. And that would be a net increase in biological age.
This might not be a problem for young mice which can eliminate SnCs fairly quickly, but it seems to be a big problem for old mice. Middle-aged mice probably lie somewhere in between. I’d also expect that overweight, obese, or otherwise messed-up, middle-aged mice would fare worse.
It’s not just background processes that can produce new SnCs, but SnCs themselves produce new, secondary SnCs too.
Imagine that each new SnC produced 3 new SnCs within a day, and also that SnCs had a 50% chance of being removed each day. In that case, there will be 4*0.5 = 2x as many SnCs tomorrow as there is today, leading to exponential runaway growth, immediately exploding in the number of SnCs and dying.
On the other hand, imagine that they only produce 1 new SnC within a day, and also that they had a 66% chance of being removed each day. In that case there will be 2*0.33 = 0.66x as many SnCs tomorrow, leading to quickly returning to the equillibrium caused by outside production.
You’d need some sort of fine-tuning where the production and removal are extremely close to each other to not either have explosive growth or rapid equillibration.
Even if the original SnCs are eventually eliminated (which isn’t entirely clear), it sure looks like they should increase the SnC baseline anyway. It’s not just background processes that can produce new SnCs, but SnCs themselves produce new, secondary SnCs too. So, it’s not unlikely that adding a bunch of SnCs to the baseline pool of SnCs (whose size increases with age) could further increase the size of this pool. And that would be a net increase in biological age.
This might not be a problem for young mice which can eliminate SnCs fairly quickly, but it seems to be a big problem for old mice. Middle-aged mice probably lie somewhere in between. I’d also expect that overweight, obese, or otherwise messed-up, middle-aged mice would fare worse.
Imagine that each new SnC produced 3 new SnCs within a day, and also that SnCs had a 50% chance of being removed each day. In that case, there will be 4*0.5 = 2x as many SnCs tomorrow as there is today, leading to exponential runaway growth, immediately exploding in the number of SnCs and dying.
On the other hand, imagine that they only produce 1 new SnC within a day, and also that they had a 66% chance of being removed each day. In that case there will be 2*0.33 = 0.66x as many SnCs tomorrow, leading to quickly returning to the equillibrium caused by outside production.
You’d need some sort of fine-tuning where the production and removal are extremely close to each other to not either have explosive growth or rapid equillibration.