I just read a paper that proposes a bit of caution when it comes to senolytic treatments.
It's a good paper to read for whoever is experimenting with senolytics right now. Some slight risks to consider.
Of more general interest is that a pre-senescent state in which stem cells express
senescence biomarker p16ink4a can be reversed. Expression of high levels of p16ink4a has
been considered a hallmark of senescence[19], though its clear that over-expression of
p16ink4a could sometimes be overcome[19]. Perhaps p16ink4a should be considered a
biomarker of deep-quiescence or pre-senescence rather than senescence, which may have
profound implications for basic and applied research
The idea that destruction of senescent cells, i.e., “senolysis,” will be of benefit to aging
mammals, such as mice and humans, has become quite popular. There are studies that
indicate that targeted destruction of p16ink4a expressing cells extends life- and health-span
or confers other anti-aging benefits [20] [21] [22] [23] [24]. Lifespan extension by ablation of
p16ink4a expressing cells remains controversial, as the reported 25% extended lifespan was
relative to a vehicle control group of mice that had a significantly shortened lifespan to what is
typically observed for the particular mouse strain studied[25]. However, if the results of
Garcia-Prat et al. are confirmed and extended to other stem cells, then senolytic approaches
that may provide some short-term health benefits, while unfortunately and simultaneously
destroying reservoirs of potentially recoverable regenerative activity, thus capping potential
health gains. To avoid such pitfalls, it may behoove anti-aging therapeutic drug designers to
develop treatments to first rescue pre-senescent stem cells, before destroying p16ink4a-
expressing “senescent” cells.
6. Conclusion
Aging results in epigenetic changes that alter muscle stem cell function, resulting in loss of
self-renewal capacity or induction of senescence. The relative importance of each of these
mechanisms in humans remains to be elucidated. Both may be subject to therapeutic
intervention. The existence of potentially recoverable pre-senescent stem cells, should inform
the development of senolytic drugs in order to prevent unintentional reduction of regenerative
capacity.
http://www.ncbi.nlm....pubmed/27000748
It's falling into the trap of looking at senolysis as a therapy on it's own and not just a step in a full treatment. I've personally said it even in the beginning of the thread that this is pretty much the expected outcome and senolytics without stem cell implantation won't give the best outcome.
Also it hangs on potential benefits you could get from putting "quasi-senescent" cells back into "working" order, very fortunately for us the medicaments they use to this end are quite well known on these forums - rapamycin and spermidine - when it comes to efficacy we already have an idea how "effective" mtor inhibitors are in a human population (there was a paper on that recently) we can easily come to our own conclusions which could be more beneficial potentially.
Also an interesting thing to note is this paper looks at cells expressing p16. The paper posted previous looks at a mechanism which has not been discussed a lot as it comes to senescence p53 - although both p53 and p16 have been known players in senescence from cancer research.
p53 is antagonistic to p50/p52 (better known as NF-kB on these forums) and there is more than enough proof too much p50/p52 is not good for you and as we know it gets increases as we age.
I'm trying to give you a fuller perspective not just a quote from a paper, but maybe I'm just rambling a lot of these things should be common knowledge on the forum by now.