This isn’t Covid-19 but there was this claim by some Israelis to have reversed the human aging process. Using oxygen. In particular, they are claiming they can lengthen telomeres and the accumulation of resulting senescent cells. [...] I assume I have some readers who can explain why this is nothing to get excited about, but seems worth asking for them to do that.
Ok, there’s a lot going on here.
First, general epistemic comments. Paper is here. There are some major red flags: only ~20 patients in analysis, no control group, tested a bunch of different cell types and endpoints. In this case, I think the lack of a control group isn’t too alarming—we have a pretty decent prior idea of what “normal” looks like in old people, and in some ways using the initial conditions of this particular group as the “control” is better anyways, especially with such a small sample size. The garden of forking paths is a bigger concern. The effect sizes and p-values are strong enough that I still think there’s plausibly a real effect here, but definitely take it with a sizable helping of salt.
The main measurements I’d pay attention to are the senescent cell counts post-treatment (the “post-HBOT”, taken “1-2 weeks” after the treatment concluded). Hyperbaric oxygen will definitely have short-term effects, but it’s mainly the longer-term effects which are interesting here, so post-HBOT is the thing to look at. Telomere length measurements in general are… kinda tricky to interpret. In normal operation, they’re effectively a downstream measurement of DNA damage rates (which are what “really” seem to matter for aging), but some interventions can lengthen telomeres without significantly reducing the damage rates. Senescent cell counts, on the other hand, seem to be more directly relevant, based on my current best understanding. Put that together, and we can ignore most of the forking paths and just focus on post-HBOT senescent cell changes.
And in this case, the post-HBOT senescent cell changes are exactly where the most dramatic results are. They looked at senescent cell counts in two cell types. One had ~37% drop in senescent cell count, the other had ~11% drop. Those are definitely not “the problem is solved” kind of numbers, especially when the 37% drop is only in one cell type, but it’s substantial.
The bigger question is how long the effect lasts. The study only checked in 1-2 weeks after treatment, which is a bit less than the typical half-life of senescent cells. What we really want to know is whether the effect persists after 6 months or a year. Given the mechanisms involved (i.e. hyperbaric oxygen, defense activation), I would expect a priori that it probably wears off after 1-2 months, and that in the long run the hyperbaric oxygen exposure accelerates aging overall.
Ok, there’s a lot going on here.
First, general epistemic comments. Paper is here. There are some major red flags: only ~20 patients in analysis, no control group, tested a bunch of different cell types and endpoints. In this case, I think the lack of a control group isn’t too alarming—we have a pretty decent prior idea of what “normal” looks like in old people, and in some ways using the initial conditions of this particular group as the “control” is better anyways, especially with such a small sample size. The garden of forking paths is a bigger concern. The effect sizes and p-values are strong enough that I still think there’s plausibly a real effect here, but definitely take it with a sizable helping of salt.
The main measurements I’d pay attention to are the senescent cell counts post-treatment (the “post-HBOT”, taken “1-2 weeks” after the treatment concluded). Hyperbaric oxygen will definitely have short-term effects, but it’s mainly the longer-term effects which are interesting here, so post-HBOT is the thing to look at. Telomere length measurements in general are… kinda tricky to interpret. In normal operation, they’re effectively a downstream measurement of DNA damage rates (which are what “really” seem to matter for aging), but some interventions can lengthen telomeres without significantly reducing the damage rates. Senescent cell counts, on the other hand, seem to be more directly relevant, based on my current best understanding. Put that together, and we can ignore most of the forking paths and just focus on post-HBOT senescent cell changes.
And in this case, the post-HBOT senescent cell changes are exactly where the most dramatic results are. They looked at senescent cell counts in two cell types. One had ~37% drop in senescent cell count, the other had ~11% drop. Those are definitely not “the problem is solved” kind of numbers, especially when the 37% drop is only in one cell type, but it’s substantial.
The bigger question is how long the effect lasts. The study only checked in 1-2 weeks after treatment, which is a bit less than the typical half-life of senescent cells. What we really want to know is whether the effect persists after 6 months or a year. Given the mechanisms involved (i.e. hyperbaric oxygen, defense activation), I would expect a priori that it probably wears off after 1-2 months, and that in the long run the hyperbaric oxygen exposure accelerates aging overall.