August 21, 2003
When Will Youthful Rejuvenation Become Possible?

Some see youthful rejuvenation as something that can be accomplished within 50 years.

A few of our more radical experts believe that, in the next 50 years, 90-year-olds could look like 30-year-olds and feel as fit as a 45-year-old thanks to an explosion in regenerative medicine, genetic research and biotechnology.

And today's children could live to 120 - or longer. The Centre for Strategic and International Studies in Washington predicts that a female born today will have a 40 per cent chance of surviving until she is 150 years old.

I don't see how someone can do a calculation to come up with a percent odds. What is more likely the case is that at some point we will reach the ability to keep people perpetually young and then life expectancy predictions will be based chiefly on non-aging related causes of death. The mystery is just when will we reach the point where we can reverse aging?

Nicholas D. Kristof of the New York Times quotes a much more radical prediction by biogerontologist Aubrey de Grey.

"Our life expectancy will be in the region of 5,000 years' in rich countries in the year 2100, predicts Aubrey de Grey, a scholar at Cambridge University. (This is, of course, a great prediction to make, because none of us will be around in 2100 to mock him if he's wrong.)

Kristof is wrong on his last point. The year 2100 is only 97 years away as of this writing. Barring the end of human civilization (which is a distinct possibility) even without advances in medicine there are already many people alive now who will be alive then. Even under the most conservative estimates of the rate of biomedical research advance it seems likely that average life expectancy will increase by decades in this century. So tens or hundreds of millions of people alive right now should live to the year 2100.

Aubrey expects that within 100 years we will have total mastery of technology for growing replacement organs, making youthful replacements of adult stem cell reservoirs in the body, the ability to eliminate accumulated of intracellular aggregate junk, and still other parts of the rejuvenation puzzle.

In an interview with The Speculist after listing what he considers to be the 7 most promising approaches for rejuvenation Aubrey says that those 7 rejuvenation approaches could all be tried in mice within a decade's time.

What do you consider a realistic timeframe for putting treatments in place that address all seven?

That's hard to say, because some of them need really good gene therapy, which is still rather black magic. I won't stop there, though, because I feel that biogerontologists have a duty to give their best guess at timescales. What I can say is that we should be able to implement all seven in mice within a decade. This is because gene therapy in mice is a lot easier, for the simple reason that we don't have to worry about safety. And the thing is that as soon as we do implement them in mice, and presuming that they give the sort of life-extension benefits I predict, the general public will realize that aging is not inevitable after all, and will push incredibly hard for more work on human gene therapy etc. to get the therapies working in humans as fast as possible.

This is key. Aubrey's attitude is that we don't have to wait for every single molecular mechanism of aging to be elucidated in excruciating detail before we start trying to role back the clock. If we take more of an angineering approach and just start trying to replace or repair what most likely needs to be replaced or repaired we can get useful anti-aging therapies much sooner.

Aubrey thinks that on the outside we will achieve engineered negligible senescence within 60 years.

Assuming you live to be 100, what will be the biggest difference be between the world you were born into and the world you leave?

Um, do you mean if I die aged 100? I fully intend not to leave the world at such a paltry age. But even if I died aged 100, that's still 60 years away far too long to be able to make such predictions. Hmm, well, in 60 years we'll definitely have aging under complete control I guess it would be difficult to imagine a bigger difference than that.

Aubrey has a lot more on his website about strategies of engineered negligible senescence.

Share |      Randall Parker, 2003 August 21 12:06 PM  Aging Reversal

Phil said at August 22, 2003 7:39 AM:

Thanks for calling Kristof on his chowder-headed comment that none of us will be here to see the beginning of the 22nd century. He presupposes that there will be no change in life expectancy over the next 97 years (actaully, that life expectancy will go down) and that the guy he's quoting is wrong in his basic assumptions.


Still, it's good to know that Aubrey is getting the attention. His work is important and should be recognized. And above all, it's important to remember (if it hasn't been pointed out enough) that I scooped the New York Times on this deal.

Not that I'm bragging or anything.

Randall Parker said at August 22, 2003 8:55 AM:


Yes, it is absolutely great to see an NY Times columnist quoting Aubrey. Any publicity is good publicity.

I've done what I can to promote Aubrey's ideas about therapies to reverse aging. See my Aging Reversal archives for my many mentions of his ideas.

BTW, I've also promoted Aubrey's ideas to regular journalists. Back in the year 2001 I sent email to the editor of Reason and to Ron Bailey of Reason asking Bailey to talk to Aubrey for an article Reason was going to run on aging. Bailey did talk to him and you can find a link to that article to the post I did on it.

Paul Banks said at August 22, 2003 8:45 PM:

Something that I would like to know; is this something that we need/want? If it is, would it not radically undermine several political philosophies, namely socialism? With a gigantic, ever growing elderly population, would not making them look nice but doing much less for their functionality cripple economies the world over?

No one wants to die (well almost no one) and few want to lose a dear one; I just lost a mother in law, and at 48 it was too young. However, from a practical standpoint, is a 200 year old a good idea? I don't know. Judging from past experience, anecdotal admittedly, most people don't change and usually generations have to pass on to make change.

Are we writing the prescription for political/social stagnation? Or would this lead to a new era of expertise?

Paul Banks
Washington University in St. Louis Law School

Randall Parker said at August 22, 2003 10:11 PM:

Paul, You should decide whether you want it for yourself. I want it for myself.

Will it solve any problems? Yes. One thing it would do is eliminate the need to retire. People would not get old and tired and mentally slow. They'd be able to keep working and pay taxes rather than collect benefits. The coming bankruptcy of old age government pension and health care systems throughout the Western countries would be avoided.

Rejuvenation wouldn't just make people look nice. It would restore people to youthful levels of mental and physical functionality.

Political and social stagnation: One reason people become set in their ways is that they become less able to learn. One reason for that is that their hippocampal stem cells become aged, slower dividing, and the resulting neurons are not as vigorous. Replenish hippocampal stem cell reservoirs and also do repairs to existing neurons and people's minds would become more supple and adaptive.

Bob said at August 23, 2003 6:52 AM:

Political stagnation? I would predict fundamental changes in the way we view politics. Right now, who really cares what the world will be like in 100 years? Sure, we want a nice place for our grandkids, but beyond that it is an irrelevant abstraction for us.

Consider the political will to initiate engineering projects with a 100 year horizon and how politics will change when we can all expect to be around for the outcome.

Paul Banks said at August 23, 2003 8:32 AM:

Bob and Randall, you both make good points. I still see huge hurdles, two that come to mind;

1. While I do see your point that people might work longer and accumulate more knowledge over the course of a lifetime, leading to a new outlook. One practical problem I see with that is human physiology; while other organs seem to be able to blend in with older Americans, for example, I was under the impression that your brain is relatively set right after puberty, and there is nothing really that can be done to generate brain cells or maintain the mind, as evidenced, for instance, by varying mental illness that causes dementia unabated in our older generations. How can people learn longer if the brain is the one thing we can't grow or maintain?

2. Bob's point, that people will have a longer view and perhaps be much more willing to leave a good planet for the future generations, seems to be counterintuitive for (at least) one reason. Ignoring the further entrenchment of corporate wealth (preventing parents from passing on money, leading them to perhaps a less egalitarian world view), the length of age is just relative. If you live 100 or 200 years, it is not that much different in the course of the planet, and likely would stagnate society further in terms of searches for planet saving energy policy, to take one example.

I see ways to address both of these somewhat, but would like input. Also, I never would try to derail this, if I could, nor am I trying to tell you what you should want. I just want your opinion on these issues, and a new one; what if rejuvination outstrips advances in food production? Would the US cut shipments to foriegn nations to supply their burgeoning populace? Would, perhaps Africa, whole continents on the other side of the technological divide, facing perhaps the same complex question of drug prices for developing nations that they do now, slowly become global minorities, or worse, extinct? I am not saying we should die young to feed Africa, but wouldn't this scenario force innovation that is potentially just not possible?

Paul Banks
Washington University in St. Louis Law School

Randall Parker said at August 23, 2003 9:22 AM:

Paul, For many decades the accepted wisdom was that the brain does not grow new cells. It was thought that we reached some point in childhood where nerve cells no longer divded. However, that belief turns out to be false. We now know that there are stem cells in the brain dividing to produce cells that migrate up into the brain to create new neurons.

This is turning out to have all sorts of therapeutic significance. Recent reports show that anti-depressants increase the amount of cell division in the brain. The delay between the time anti-depressant drug therapy is started and the time that anti-depressant effects are seen is roughly equal to the amount of time it takes for the anti-depressants to stimulate cell growth.

Also, with this knowledge that new neuron formation is possible it is hoped to treat Parkinson's to replace lost dopaminergic neurons lost in the areas that control movement.

The other problem is how to rejuvenate existing cells? Answer: gene therapy. Send in new software to construct repair systems to fix each cell. Also, nanotech repair devices will eventually become possible.

If the poorest people on the planet became minorities then that would be a good thing. A larger fraction of the planet would be affluent.

People aren't going to grow old and die at age 150 or 200. Make it that far and technology will have advanced so far that one will be able to stay young indefinitely.

Bob said at August 23, 2003 9:32 AM:


The brain is less fixed than you think. Stem cells move to the brain and repair damage. Anti-depressants cause the hippocampus to grow. As our knowledge improves, we will be able to stimulate brain growth and repair aging related deterioration of the brain.

My point about long term engineering projects has nothing to do with leaving a better planet for future generations. It has to do with supporting major engineering interventions over a very long timespan for one's own future benefit and how this will affect people's political outlook.

100 or 200 years is nothing. Think thousands of years. How would your outlook change if you could expect to be around in 5000 years?

I see no reason for the population to explode. Fertility declines with increased affluence and longevity. The population only explodes where people live short brutal lives.


Phil Bowermaster said at August 24, 2003 6:33 AM:


Okay, so it turns out that you scooped me. But what's the big deal? It was only by two years!



Phil Bowermaster said at August 24, 2003 6:48 AM:


Bob's suggestion that a longer-lived population will be better custodians of the planet has merit. A while back I was having the brakes fixed on my car. The guy offered me two choices for the repair, one of which was more expensive but would ensure that the brakes would hold up nicely for several years. The thing is, the car was on a lease that was due to expire in about six months. I went with the cheaper option, because I had no stake in the performance of the car's brakes three or four years down the road. Had I expected to be driving the car for another five or ten years, or for an indefinite period into the future, I would have chosen differently.

I think most people in my position would make the same choices.

A cure for aging means we all get an indefinite extension on our leases. Don't you think most people will want to take care of their brakes?



Bob said at August 24, 2003 7:13 AM:


I don't think we will necessarily be better custodians. For instance, if the mechanic gave you two choices where the price was the same but the longer lasting brake caused more pollution, you might pick the polluting brake if you intend to keep the car longer.

Likewise with politics, we might support things that are very bad for the environment because some large block of voters perceives a direct benefit to them in 50 years. The point is people will value things differently and will place greater value on longer term issues.

In a sense, the end of aging will change one aspect of human nature, but it won't change all of human nature.


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