Ok... well I'm going overboard quite a lot here. First of all, while this may, in fact, be true, what I'm going to present below might not be a path to do it; it's just some speculation. However, it's possible that what I'm going to present has an "anti-aging effect", that partially reverses the aging process.
Before I explain, let me reinforce the "speculation" caveat: I'm not a biologist, or gerontologist; so this is only speculation, and wild speculation at that.
Now that we have that out of the way, let me remind you of the result from last year, about partially reversing the epigenetic clock, through a combination of Human Growth Hormone, Metformin, DHEA, Zinc, and vitamin D supplementation:
(The usual skeptic comments should be noted: it's a small study; there was no control; the subjects were anti-aging fanatics, and could have done something else, outside the scope of the study, to bring down their clocks.)
Assuming that this is indicative of a genuine anti-aging process, one thing to note is that it wasn't complicated. The body knew how to reverse the clock already; all that was needed was a little jolt from the HgH and other supplements.
A subsequent study we heard about a few weeks ago, in which Horvath was also a coauthor (so far, it's only a preprint), also appears to have involved a relatively simple intervention, in rats this time -- again, it sounds like the (rat) body knew how to reset the clock, and de-age the rats (of course, assuming that the result is replicable):
A complete theory of how they think it works is not detailed in this paper (at least not that I could find, based on a quick scan).
Josh Mitteldorf mentions something interesting on his webpage describing the work:
A question that remains unresolved concerns the location and mechanism of the aging clock. I have been undecided over the years between two models:
1. There is a central aging clock, perhaps in the hypothalamus, which keeps its own time and transmits signals throughout the body that coordinate methylation state of dispersed tissues
2. Information about epigenetic age is dispersed through the body, and the body’s clock is a feedback loop that is continually updating methylation age locally in response to signals received about the methylation age globally.
He brings up the possibility that the hypothalamus is responsible for "keeping time" and transmitting it to other parts of the body. He also has a separate blog entry about the role of the hypothalamus in the aging clock:
What I wondered was whether neurofeedback might somehow cause the hypothalamus, pituitary, or other structures to reset the aging clock.
I don't actually know whether neurofeedback is even possible directly with these structures; but it is possible with other structures they are connected to, such as the amygdala. So, perhaps through neurofeedback with the amygdala -- or other brain regions -- one can induce the hypothalamus and/or pituitary to reset the clock.
Interestingly, the brains of super-agers -- that is, people who live a very long time -- appear to resemble the brains of people several decades younger:
Maybe it isn't just that their young brains are part of the overall package of slowed-aging. Maybe that's backwards: their young brains cause the hypothalamus to slow down the clock for the whole body.
Now I want to talk about another aspect of this: several years ago, I was pretty skeptical of anti-aging research, and raised the possibility of "system-level aging" -- that "cellular aging" doesn't account for all the different types of aging in the body. What I meant specifically was that there could be a type of "aging" induced by the interrelationships among different cells in the body. That is, if you measured the age of each cell, individually, you might find that they were "young", and that none of them were too far out of place in their respective tissues; but that the collective error in their arrangement, and in how they communicate, caused a breakdown in their collective function.
What gave me the idea for this was a talk I saw online by the neuroscientist Chris Eliasmith, where he talked about how our "neural representations" of knowledge break down over time, and that half of it has nothing to do with the death of neurons; it's simply the result of the overall dynamics of the brain breaking down. That is an example of system-level aging. Here's perhaps another example, along with a fix:
The researchers attribute this improvement to changes in synchronization and coupling within the brain. Basically, the electrical and information flow within networks and between different networks in the older brains was out of rhythm and mild electrical stimulation was able to get them back in sync again, at least in the short term. This was reflected in changes in the patterns of gamma waves and delta waves on people's electroencephalographs (EEGs).
The old brains were just out of rhythm, and all it took was a simple intervention to correct it, at least temporarily.
Another example that is even more amazing:
Simply by flashing light at a specific frequency -- flashes at 40 hertz -- at mice, one can induce their brains to clean up beta-amyloid and tau plaques (that occur in Alzheimer's), and other harmful debris, by activating microglia cells. The repair mechanism was there all along -- it just needed to be activated.
Could something similar be happening all over the body?
One possibility is that the way that we age is that our bodies have these extremely powerful mechanisms to prevent cellular aging -- they clean up junk, correct errors in DNA, flush out dead cells, recycle mitochondria, and so on -- but that, over time, the larger systems that coordinate them, break down; in fact, break down much faster than the smaller repair mechanisms themselves. In other words, we age much faster at the system-level than we do at the cellular level; but then that aging at the system-level is ultimately what causes the whole structure to fall, and even accelerates cellular aging.
It's kind of like having a world-class group of musicians being led by a bumbling, old fool conductor. They start to play, and play well in the beginning; but then make mistakes, because the conductor doesn't give them good direction, and it eventually all falls apart, and the curtain is pulled down to avoid further embarrassment.
What would cause the global systems to form in the first place, and why would they age?
Well, I recall reading various theories about whether and how the brain learns to do "gradient descent learning". One of these theories is that the brain is a meta-learner. e.g. individual neurons may use Reinforcement Learning to learn how to learn; and, since Gradient Descent is a method that might be near-optimal, among learning algorithms, the neurons learn to do that:
(I've not read this very carefully yet, actually... I'm mostly basing what I just wrote on a little lecture I saw by Kording, one of the authors of this paper.)
Maybe something similar happens all over the entire body. Instead of "learning to learn", maybe certain cells... certain structures "learn to coordinate". There would be some general outlines for how various body coordination mechanisms should work coded in our DNA; but then a large part of it would also be learned, somehow.
Everything would work fine... for a little while... until, like with the brain dynamics breaking down -- leading to our inability to separate concepts -- all these coordinating systems of the body stop doing their jobs. The conductors aren't able to conduct their world-class orchestras, and the shows all end in embarrassment.
But... like with re-synchronizing the brain as in that example above, and also the example with 40 hertz strobe light, maybe the conductors can be put back in rhythm, and everything works like new.
Maybe the conductors, themselves, have conductors... all the way up to some master conductor in the brain -- that, hopefully, can be re-tuned with neurofeedback.
Unfortunately, neurofeedback is still in its infancy. A lot of experiments would be needed to figure out just how powerful a technique it is -- and whether it can even be used to slow (or reverse) aging.
But it would be really cool if the only thing you needed to slow or reverse aging was a good brain-computer interface, and some software to run the neurofeedback (and, of course, a computer to run it on).