5 ms·

Well, once we discover a way to prevent or reverse aging, everything else would be a matter of time, of which you would now have an effectively unlimited amount

Well, once we discover a way to prevent or reverse aging, everything else would be a matter of time, of which you would now have an effectively unlimited amount.

pdm55 5y ago
I have never believed the argument that we can develop a way to live to 200. I am now in my mid 60s and it seems that a number of my parts are starting to "wear out". My skin is certainly thinner; my eyesight is damaged (macula degeneration) in one eye; ... And covid has taught us that our immune systems are not as effective as when we were younger. We older folks all see heart and cancer problems over the horizon. Cancer just seems a matter of time: I mean how can our cells keep replicating the 3 billion(?) base pairs in our genomes - with a mistake rate of about 1 per 100 000 (i.e. 30k mistakes per division) - without those eventually leading to cancer? And if I could only remember how to spell that alzyhmr thing, I would mention it also. And why does our government keep sending me those kits for faeces samples? Sorry to disagree with you, but I don't think aging is a reversible process: we seem to have too many parts, each with an "expiry date".
- finolex1 5y ago
  Not a biologist, but certain sharks, whales and tortoises have been known to live for >150 years, so I suppose it is theoretically possible.
  - ejolto 5y ago
    Greenland shark reach sexual maturity at 150 years, and can live for over 400 years according to Wikipedia.
- dwohnitmok 5y ago
  The main reason why it seems like it's not just a matter of "parts wearing out" is that different animals all age at different rates, but strikingly they all seem to age in similar ways. For example while dogs have a much shorter lifespan than humans they seem to face all the same age-related declines humans face. This holds for animals close to or exceeding our mass as well. If different parts of the body wore out simply due to e.g. mechanical stress, you would expect e.g. dog joints to be perfectly healthy after 15 years since they are biologically very similar to human joints, when in fact dogs tend to still have arthritic and otherwise fragile joints at 15 (or earlier). Everything declining together, just on different timetables in different animals, seems to suggest that aging is controlled by either a single mechanism or some interwoven set of mechanisms that cause everything to fail at the same time, rather than individual parts failing because "they wear out." If you could target that mechanism(s) then maybe you can make humans live as long as e.g. tortoises. But of course we haven't confirmed that such things exist, but the above is at least some motivation for why they might exist.
  - honzzz 5y ago
    I would guess it is because there was no evolutionary pressure to have joints that can sustain 80 years if there are other parts of body that only sustain 18. Maybe I am missing something but I would expect that life expectancy of various parts of body of each specie converge because of that.
    - dwohnitmok 5y ago
      Evolution is rarely so tidy in its convergence. Humans have vestigial organs and crazy anatomical features left over from our ancestors. In light of that it would be a rather stunning coincidence to find that when it comes to aging across species (!) that organisms seem to have all their systems age at the same rate simply by individual evolution of each of those systems or that all the systems are effectively immortal with nothing in-between. Without a coherent theory of senescence this is all conjecture, but there's compelling evidence that there's some set of hidden variables we aren't seeing that is "pulling the strings" when it comes to aging.
      - honzzz 5y ago
        What compelling evidence?
        dwohnitmok 5y ago
        On reflection evidence is too strong a word given that we don't have a good, specific hypothesis for what's going on. Observations of the sort I laid out above.
- nrdvana 5y ago
  Every cell in your entire body (on average) gets replaced over a 7 year span. If you figure that you stopped growing around 18, and your body has been slowly replicating itself since then, it completed the first full replication at 25, the second at 32, the third at 39, the fourth at 46, etc. Each time you accumulate some chaos. As the chaos grows, the cell groups decline in performance. The decline in performance makes it more likely that the next replication will be even worse. While that makes it really unlikely that aging can be reversed, it certainly isn’t logically impossible. All you need to do is expell the chaos, and get one good quality regeneration (possibly taking about 7 years) and then you’d be right back to 18 years old again. That might make it worthwhile enough to be willing to have your body burned by a billion laser shots and float in a vat of liquid for 7 years. We might get to find out in our lifetimes? who knows.
  - gscott 5y ago
    Good movie on the subject https://www.imdb.com/title/tt8548830/ https://www.imdb.com/title/tt8548830/
- grishka 5y ago
  Not a biologist, but I'm following related research and at this point am fairly convinced that aging is an intentional, pre-programmed process, as opposed to the popular understanding that it's the consequence of wear and tear. Let's just think logically about it for a bit. Your cells come with all kinds of repair machinery and redundant DNA encoding. All cells do. But there are single-celled creatures that don't age and reproduce by cell division, and they haven't lost their function despite billions of years and millions of generations. Same for humans and whoever else reproduces sexually — there's A LOT that needs to go just right for a new human to be born, including making billions of copies of parents' DNA, yet it does work just fine most of the time. This tells us that the DNA copying process must be very robust, and that with age, it's these mechanisms that keep everything in check that deliberately get weaker or stop working altogether. Recent research proves it. For example, there's evidence that organisms propagate their age throughout all tissues using some kind of signaling in the bloodstream: https://www.nature.com/articles/ncomms13363 https://www.nature.com/articles/ncomms13363 Even more bizarre, the aging clock, as determined by DNA methylation, gets reset to zero at the beginning of embryonal development: https://hplus.club/blog/how-and-when-mother-nature-resets-the-aging-clock-and-why-the-wear-and-tear-theory-of-aging-is-worn-out/ https://hplus.club/blog/how-and-when-mother-nature-resets-th...
  - ak217 5y ago
    You're not wrong, but your models of aging events seem to be too simplistic. Aging is not one process but a complex of interacting processes. There are definitely a number of processes involved in aging that are pre-programmed as you suggest, namely the hormonal clocks involved in puberty and maturation, and then later senescence. It's not particularly useful to compare humans/mammals to single-celled organisms, which operate under way fewer constraints. They don't have to deal with cancer, as just one very basic example. They also don't have to figure out how to clear old junk from their tissues and individual cells. They just start over with a clean slate every time. Signals in the bloodstream - various hormones and immune cells - are obviously involved in aging. But there are many of them, and we are just starting to understand their different interactions. There is no doubt that aging research is going to yield ways to suppress or promote the action of certain hormones, replenish/reactivate certain stem cell populations, etc. but better understanding of intercellular regulatory networks is needed for that. To call DNA methylation the determinant of an "aging clock" is also too narrow or simplistic. DNA methylation is the mechanism of cell differentiation, but it's "metadata" that has to be copied over between cells when they divide, just like the DNA itself. Early in embryogenesis, the DNA methylation pattern is reset and overwritten using the regulatory cascade of master control genes (homeobox, etc.) - so it is expected that the methylation pattern will have lower fidelity with each division cycle before or after that point. This is the golden age of biology - we have just gotten a hold of the tools that will let us solve these problems - but it's messy and complicated. Investing in your understanding of these processes can have a huge payoff - I recommend reading some of the Nature Reviews articles like https://www.nature.com/nrg/ https://www.nature.com/nrg/ - I've always found them to be incredibly helpful in summarizing the state of the art.
amrcnimgrnt 5y ago
You can't reverse aging, that's a violation of the second law of thermodynamics. You might be able to restore the body's ability to regenerate itself. But that's a terrible idea. I shudder at the idea of living to 120, never mind 200. Imagine being born in 1821 and having to live today. Imagine how confusing that would be.
- elzbardico 5y ago
  >You can't reverse aging, that's a violation of the second law of thermodynamics. We are not closed Systems
  - amrcnimgrnt 5y ago
    Reversing the flow of aging is reversing entropy locally, so you're, overall, increasing entropy more outside of your body. The live forever types are just assuming that energy will be plentiful enough to sustain hundreds of billions of people indefinitely [1] and heat easy to dissipate [1] The population of the earth is stable at 7 billion only because people have this nasty habit of dying. If we stopped doing that, the population would grow exponentially at the birth rate of 1.7%. Or a doubling every 42 years. In 160 years (not that far off from the current record of longevity) the world's population would hit 100 billion people. Of course the "live forever" types never mention that eternity is a promise for the privileged, and not for the masses.
  - dennis_jeeves 5y ago
    >We are not closed Systems Thanks that's the right way to put it.
- distantaidenn 5y ago
  Huh? If you were an immortal, you don't just suddenly appear out of time. A person born in 1821 and still alive today would know more about the world than anyone else.
  - anyfoo 5y ago
    Yeah. I was born and lived before the Internet (in its widespread form) existed. Life was very different back then, and I am not confused. As long as changes happen gradually, I don't see the problem. If they don't, people of almost all ages will be confused.
r00f 5y ago
if we do, we will die of starvation and pollution pretty soon, unless we start making wonders really fast
KSteffensen 5y ago
I would not want to be born into a society where everyone else has lived for hundreds of years.
- grishka 5y ago
  In a society where there's a cure for aging, dying of old age would be regarded the same way as we would think today of a person who dies of a bacterial infection by refusing to take antibiotics. Yet bacterial infections used to be inevitably deadly for most of the human history.
ineedasername 5y ago
I think that would be very difficult without a much better understanding of our bodies, so it becomes a chicken/egg problem. Aging isn't really just one thing, it is a constellation of factors that often comingle to make the process even worse. I frequently see Telomere "reset" referenced as the big thing that would win or achieved the most gains in the war on aging, but that seems like it would only be an incremental gain. Here's a good overview on the topic: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4712935/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4712935/ Also consider that long life may not produce the advancements you might hope for. There's a saying: "Science progresses one funeral at a time." It's a reference to the fact that individuals typically hold fast to their ideas-- scientists included. Certainly we may react to & integrate new knowledge, but at some fundamental level we are hindered by the cognitive foundations of knowledge laid down when we're younger that are not automatically escaped on new information. That's not even accounting for pride & ego causing people to cling even more fiercely to their own ideas. You might think that on ongoing infusion of new talent would prevent this, but massively extended age would also entrench the older generations firmly into the power structures of the scientific community, creating at least a partial gerontocracy. Heck we have a bit of that now: Plenty of PhD candidates get stuck "playing the game" and not bucking the status quo too much, only guided down paths their advisors find acceptable. If you have something that significantly contradicts the current consensus, then without a very good & open minded advisor willing to go to bat for you, you might as well shelve it, do something mundane & acceptable for your dissertation, and dust off that other idea when you're done. This situation would not improve with the further ossification of power structures. If we got there though-- massively extended lifespans, the gerontocracy aspect of things in society in general would be also be a difficult sociological issue. With a 300 year lifespan, by the time you got to 200 you would probably consider anyone under the age of 50 as little more than children. The issue of wealth inequality would be incredible as generational wealth accumulated by anyone remotely careful with their finances would, by late-middle age, dwarf the resources of anyone starting out. There could be some interesting & positive aspects to all of that though too. Imagine have half a century to explore intellectually or otherwise before you were expect to settle into a path in life. And if we found societal of medical methods to help people break out of psychological & intellectual inertia then a person might expect to have multiple very different careers in their lifetime. Anyway, all of that would be a very long ways off. At my age I might still hope that leaps in medical advances could give me an extra 10 years of productive healthy life, but probably not much more. And I've also gone a long ways off the original topic, so I'll end it here.
snvzz 5y ago
SENS[0] is engineering (not discovering) a way. And they are not that far off. [0]: https://www.sens.org/ https://www.sens.org/

Well, once we discover a way to prevent or reverse aging, everything else would be a matter of time, of which you would now have an effectively unlimited amount.

pdm55 5y ago

I have never believed the argument that we can develop a way to live to 200. I am now in my mid 60s and it seems that a number of my parts are starting to "wear out". My skin is certainly thinner; my eyesight is damaged (macula degeneration) in one eye; ... And covid has taught us that our immune systems are not as effective as when we were younger. We older folks all see heart and cancer problems over the horizon. Cancer just seems a matter of time: I mean how can our cells keep replicating the 3 billion(?) base pairs in our genomes - with a mistake rate of about 1 per 100 000 (i.e. 30k mistakes per division) - without those eventually leading to cancer? And if I could only remember how to spell that alzyhmr thing, I would mention it also. And why does our government keep sending me those kits for faeces samples? Sorry to disagree with you, but I don't think aging is a reversible process: we seem to have too many parts, each with an "expiry date".

finolex1 5y ago
Not a biologist, but certain sharks, whales and tortoises have been known to live for >150 years, so I suppose it is theoretically possible.
- ejolto 5y ago
  Greenland shark reach sexual maturity at 150 years, and can live for over 400 years according to Wikipedia.
dwohnitmok 5y ago
The main reason why it seems like it's not just a matter of "parts wearing out" is that different animals all age at different rates, but strikingly they all seem to age in similar ways. For example while dogs have a much shorter lifespan than humans they seem to face all the same age-related declines humans face. This holds for animals close to or exceeding our mass as well. If different parts of the body wore out simply due to e.g. mechanical stress, you would expect e.g. dog joints to be perfectly healthy after 15 years since they are biologically very similar to human joints, when in fact dogs tend to still have arthritic and otherwise fragile joints at 15 (or earlier). Everything declining together, just on different timetables in different animals, seems to suggest that aging is controlled by either a single mechanism or some interwoven set of mechanisms that cause everything to fail at the same time, rather than individual parts failing because "they wear out." If you could target that mechanism(s) then maybe you can make humans live as long as e.g. tortoises. But of course we haven't confirmed that such things exist, but the above is at least some motivation for why they might exist.
- honzzz 5y ago
  I would guess it is because there was no evolutionary pressure to have joints that can sustain 80 years if there are other parts of body that only sustain 18. Maybe I am missing something but I would expect that life expectancy of various parts of body of each specie converge because of that.
  - dwohnitmok 5y ago
    Evolution is rarely so tidy in its convergence. Humans have vestigial organs and crazy anatomical features left over from our ancestors. In light of that it would be a rather stunning coincidence to find that when it comes to aging across species (!) that organisms seem to have all their systems age at the same rate simply by individual evolution of each of those systems or that all the systems are effectively immortal with nothing in-between. Without a coherent theory of senescence this is all conjecture, but there's compelling evidence that there's some set of hidden variables we aren't seeing that is "pulling the strings" when it comes to aging.
    - honzzz 5y ago
      What compelling evidence?
      - dwohnitmok 5y ago
        On reflection evidence is too strong a word given that we don't have a good, specific hypothesis for what's going on. Observations of the sort I laid out above.
nrdvana 5y ago
Every cell in your entire body (on average) gets replaced over a 7 year span. If you figure that you stopped growing around 18, and your body has been slowly replicating itself since then, it completed the first full replication at 25, the second at 32, the third at 39, the fourth at 46, etc. Each time you accumulate some chaos. As the chaos grows, the cell groups decline in performance. The decline in performance makes it more likely that the next replication will be even worse. While that makes it really unlikely that aging can be reversed, it certainly isn’t logically impossible. All you need to do is expell the chaos, and get one good quality regeneration (possibly taking about 7 years) and then you’d be right back to 18 years old again. That might make it worthwhile enough to be willing to have your body burned by a billion laser shots and float in a vat of liquid for 7 years. We might get to find out in our lifetimes? who knows.
- gscott 5y ago
  Good movie on the subject https://www.imdb.com/title/tt8548830/ https://www.imdb.com/title/tt8548830/
grishka 5y ago
Not a biologist, but I'm following related research and at this point am fairly convinced that aging is an intentional, pre-programmed process, as opposed to the popular understanding that it's the consequence of wear and tear. Let's just think logically about it for a bit. Your cells come with all kinds of repair machinery and redundant DNA encoding. All cells do. But there are single-celled creatures that don't age and reproduce by cell division, and they haven't lost their function despite billions of years and millions of generations. Same for humans and whoever else reproduces sexually — there's A LOT that needs to go just right for a new human to be born, including making billions of copies of parents' DNA, yet it does work just fine most of the time. This tells us that the DNA copying process must be very robust, and that with age, it's these mechanisms that keep everything in check that deliberately get weaker or stop working altogether. Recent research proves it. For example, there's evidence that organisms propagate their age throughout all tissues using some kind of signaling in the bloodstream: https://www.nature.com/articles/ncomms13363 https://www.nature.com/articles/ncomms13363 Even more bizarre, the aging clock, as determined by DNA methylation, gets reset to zero at the beginning of embryonal development: https://hplus.club/blog/how-and-when-mother-nature-resets-the-aging-clock-and-why-the-wear-and-tear-theory-of-aging-is-worn-out/ https://hplus.club/blog/how-and-when-mother-nature-resets-th...
- ak217 5y ago
  You're not wrong, but your models of aging events seem to be too simplistic. Aging is not one process but a complex of interacting processes. There are definitely a number of processes involved in aging that are pre-programmed as you suggest, namely the hormonal clocks involved in puberty and maturation, and then later senescence. It's not particularly useful to compare humans/mammals to single-celled organisms, which operate under way fewer constraints. They don't have to deal with cancer, as just one very basic example. They also don't have to figure out how to clear old junk from their tissues and individual cells. They just start over with a clean slate every time. Signals in the bloodstream - various hormones and immune cells - are obviously involved in aging. But there are many of them, and we are just starting to understand their different interactions. There is no doubt that aging research is going to yield ways to suppress or promote the action of certain hormones, replenish/reactivate certain stem cell populations, etc. but better understanding of intercellular regulatory networks is needed for that. To call DNA methylation the determinant of an "aging clock" is also too narrow or simplistic. DNA methylation is the mechanism of cell differentiation, but it's "metadata" that has to be copied over between cells when they divide, just like the DNA itself. Early in embryogenesis, the DNA methylation pattern is reset and overwritten using the regulatory cascade of master control genes (homeobox, etc.) - so it is expected that the methylation pattern will have lower fidelity with each division cycle before or after that point. This is the golden age of biology - we have just gotten a hold of the tools that will let us solve these problems - but it's messy and complicated. Investing in your understanding of these processes can have a huge payoff - I recommend reading some of the Nature Reviews articles like https://www.nature.com/nrg/ https://www.nature.com/nrg/ - I've always found them to be incredibly helpful in summarizing the state of the art.

amrcnimgrnt 5y ago

You can't reverse aging, that's a violation of the second law of thermodynamics. You might be able to restore the body's ability to regenerate itself. But that's a terrible idea. I shudder at the idea of living to 120, never mind 200. Imagine being born in 1821 and having to live today. Imagine how confusing that would be.

elzbardico 5y ago
>You can't reverse aging, that's a violation of the second law of thermodynamics. We are not closed Systems
- amrcnimgrnt 5y ago
  Reversing the flow of aging is reversing entropy locally, so you're, overall, increasing entropy more outside of your body. The live forever types are just assuming that energy will be plentiful enough to sustain hundreds of billions of people indefinitely [1] and heat easy to dissipate [1] The population of the earth is stable at 7 billion only because people have this nasty habit of dying. If we stopped doing that, the population would grow exponentially at the birth rate of 1.7%. Or a doubling every 42 years. In 160 years (not that far off from the current record of longevity) the world's population would hit 100 billion people. Of course the "live forever" types never mention that eternity is a promise for the privileged, and not for the masses.
- dennis_jeeves 5y ago
  >We are not closed Systems Thanks that's the right way to put it.
distantaidenn 5y ago
Huh? If you were an immortal, you don't just suddenly appear out of time. A person born in 1821 and still alive today would know more about the world than anyone else.
- anyfoo 5y ago
  Yeah. I was born and lived before the Internet (in its widespread form) existed. Life was very different back then, and I am not confused. As long as changes happen gradually, I don't see the problem. If they don't, people of almost all ages will be confused.

r00f 5y ago

if we do, we will die of starvation and pollution pretty soon, unless we start making wonders really fast

KSteffensen 5y ago

I would not want to be born into a society where everyone else has lived for hundreds of years.

grishka 5y ago
In a society where there's a cure for aging, dying of old age would be regarded the same way as we would think today of a person who dies of a bacterial infection by refusing to take antibiotics. Yet bacterial infections used to be inevitably deadly for most of the human history.

ineedasername 5y ago

I think that would be very difficult without a much better understanding of our bodies, so it becomes a chicken/egg problem. Aging isn't really just one thing, it is a constellation of factors that often comingle to make the process even worse. I frequently see Telomere "reset" referenced as the big thing that would win or achieved the most gains in the war on aging, but that seems like it would only be an incremental gain. Here's a good overview on the topic: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4712935/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4712935/ Also consider that long life may not produce the advancements you might hope for. There's a saying: "Science progresses one funeral at a time." It's a reference to the fact that individuals typically hold fast to their ideas-- scientists included. Certainly we may react to & integrate new knowledge, but at some fundamental level we are hindered by the cognitive foundations of knowledge laid down when we're younger that are not automatically escaped on new information. That's not even accounting for pride & ego causing people to cling even more fiercely to their own ideas. You might think that on ongoing infusion of new talent would prevent this, but massively extended age would also entrench the older generations firmly into the power structures of the scientific community, creating at least a partial gerontocracy. Heck we have a bit of that now: Plenty of PhD candidates get stuck "playing the game" and not bucking the status quo too much, only guided down paths their advisors find acceptable. If you have something that significantly contradicts the current consensus, then without a very good & open minded advisor willing to go to bat for you, you might as well shelve it, do something mundane & acceptable for your dissertation, and dust off that other idea when you're done. This situation would not improve with the further ossification of power structures. If we got there though-- massively extended lifespans, the gerontocracy aspect of things in society in general would be also be a difficult sociological issue. With a 300 year lifespan, by the time you got to 200 you would probably consider anyone under the age of 50 as little more than children. The issue of wealth inequality would be incredible as generational wealth accumulated by anyone remotely careful with their finances would, by late-middle age, dwarf the resources of anyone starting out. There could be some interesting & positive aspects to all of that though too. Imagine have half a century to explore intellectually or otherwise before you were expect to settle into a path in life. And if we found societal of medical methods to help people break out of psychological & intellectual inertia then a person might expect to have multiple very different careers in their lifetime. Anyway, all of that would be a very long ways off. At my age I might still hope that leaps in medical advances could give me an extra 10 years of productive healthy life, but probably not much more. And I've also gone a long ways off the original topic, so I'll end it here.

snvzz 5y ago

SENS[0] is engineering (not discovering) a way. And they are not that far off. [0]: https://www.sens.org/ https://www.sens.org/