Last month a couple of noted YouTube channels, in collaboration with the Life Extension Advocacy Foundation, published a set of popular videos that covered aging and the rationale for seeking to control aging through new medical technologies, aimed at laypeople unfamiliar with both the current promising state of the science and recent years of advocacy for rejuvenation research. The videos are quality productions and were quite widely viewed - a good job on the part of all those involved. We can hope that some of the many viewers will stop to think about how they can help to make this vision for the future a reality, and ultimately find their way to our community. The SENS Research Foundation and other groups working on the foundations of rejuvenation therapies need a larger grassroots movement and greater support if they are to make progress as rapidly as possible towards the realization of a complete suite of treatments to repair all of the cell and tissue damage that causes aging.
As a follow-up, the Kurzgesagt organization today published a second video that explaining at a high level the scientific basis behind a few of today's contending therapies: senolytics to remove senescent cells; NAD+ supplementation, such as via nicotinamide riboside; and some of the many varieties of stem cell therapies. Like the earlier videos it is well-crafted, and the more people who learn about the existence of senescent cells and senolytic therapies the better in my opinion.
Of these approaches, only the first is a SENS-like approach of damage repair, addressing a root cause rather than a secondary issue that results from some combination of root causes. Delivery of NAD+ attempts to override reductions that occur due to cellular reactions to rising levels of damage, a case of revving up a damaged engine. Present stem cell therapies work through signaling changes, temporarily making the signal environment less inflammatory and more conducive to regeneration - and the changes in cell signaling with aging definitely have the look of a reaction to damage, not a form of damage themselves. There is a future of stem cell therapies that involves replacing failing stem cell populations with new, fresh cells - but we are not there yet, and that is not what is achieved by near all present stem cell medicine.
The split of therapies in the video between those that have the potential to truly reverse aging by reversing its causes, and those that can only achieve more modest effects because they fail to address root causes is emblematic of the divisions in the present field of research and development. It is the case that immediately after the battle to convince people that extension of healthy life spans is possible, plausible, and desirable, comes the battle over exactly how to proceed. There are plenty of very different opinions on that topic. This is a much better position to be in, since it will eventually come down to hard evidence for and against specific approaches, as potential therapies are tested in animal studies and human trials - senolytics are very much more reliable and broadly effective in turning back measures of aging than just about anything else tried to date, for example. Nonetheless, this second battle is just as vital, lest time and funding be wasted on strategies that cannot possibly produce large and reliable gains.
The scientific effort to treat aging as a medical condition is still a tiny fraction of the efforts that go towards trying and failing to cope with aging, putting minimally effective patches on the symptoms, small and limited gains obtained at great expense. Of the efforts to treat aging, the majority of researchers and funding sources are not focused on what would be considered root causes in the SENS model of damage accumulation. The competing Hallmarks of Aging and Seven Pillars models overlap with SENS in theirs lists of causes, but some of them are clearly secondary effects from the SENS point of view, such as telomere length and epigenetic changes.
From an outsider's point of view, you'll see scientists backing senolytics, a true rejuvenation therapy that reverses a root cause of aging, and scientists backing NAD+ replacement, an attempt to partially compensate for consequences of the root causes, but which fails to actually address those causes. The former should be expected to be much, much better than the latter. But it'll take years for the studies to run through to prove that, and for the various champions to be vindicated or defeated. This will be the struggle for the next decade or two: to prioritize efforts that are much more likely to produce large effects on aging, and which are truly rejuvenation therapies capable of being applied again and again in the same individual for continued reversal of aging, rather than compensatory treatments that may produce modest benefits, but that leave the underlying causes of aging untouched and marching on to their inevitable conclusion.