IEET > Fellows > Aubrey de Grey > HealthLongevity
Nanotech in Medicine
Aubrey de Grey   Sep 7, 2005   Always On  

How we’ll maintain life extension escape velocity into the 22nd century.

Aging kills 100,000 people every single day–that’s two thirds of all deaths. Most of us don’t think about this much, and there’s a very good reason. Aging is ghastly but it’s absolutely inevitable, so we put it out of our minds.

Yet, our refusal to take aging seriously is a big problem at this moment, because aging is no longer so inevitable. My colleagues at Cambridge and I are rapidly getting the measure of aging: we have a pretty thorough grasp of the molecular and cellular differences between 20-year-olds and 40-year-olds that contribute to giving the 40-year-olds less long to live on average. There’s still a huge amount to learn about the processes that turn young adults into older adults, but we don’t necessarily need to know much about that in order to maintain youth.

Just as you don’t need to know much about the chemistry of rusting in order to remove rust from your car, we can in principle just go in and repair the consequences of the largely mysterious aging processes. If we periodically repair the molecular and cellular damage that eventually gets too abundant for the body to handle, which can also gradually kills us, that dam and gradually kills us, that damage will simply never become that abundant, so we’ll remain youthful.

And that’s what we’re rapidly working on how to do. If the necessary funding materializes soon, we have a 50/50 chance of developing genuine life-extension therapies–ones that can rejuvenate middle-aged people well enough to add possibly 30 healthy years to their lives–within the next 25 years. There’s lots of research to do, so it might take a lot longer–maybe even a century or more–but a 50/50 chance is a pretty good reason to try.

Now, supposing those therapies arrive, what’s next? Why would we gain only 30 extra years and not 300? Anyone who’s watched a vintage car race knows that it’s possible, with enough time and dedication, to keep those cars on the road forever. Vintage cars do “die”, but only when their owners die or lose interest. In other words, we know all we need to know about how to negate everything that goes wrong with cars over time.

One day we may reach that point for human bodies too, although I’m quite certain we won’t reach it in as little as 25 years. Human bodies are so complicated that we’ve absolutely no chance of figuring out every last detail of aging that soon.

Does that mean everyone alive today will certainly die before the age of 150? The answer is no. The reason is a concept that I been calling “life extension escape velocity”. The problem is with the damage that accumulates with age that eventually becomes too abundant for the body to handle–but before then, below that amount, it’s harmless.

There are a few different types of damage–I normally group them into seven major categories–and each of them needs to be held below that threshold level of abundance. Each one of them can kill us on its own if there’s too much of it. But there is a loophole: within each category, there are easier and harder subtypes of damage, and the subtypes do not all have to be fixed at once.

This is a bit abstract; so here is an example. One of the seven categories is stiffening of long-lived material made of proteins, such as the lens of the eye and the artery wall. This stiffening is the result of a lot of complicated chemical reactions between the proteins that make up the material and sugar molecules in the blood stream. It turns out that these reactions end up forming new chemical links that glue the proteins together to an excessive degree. These links have lots of different structures, but they all contribute to the same ultimate problem - stiffening of the material.

If we work on how to remove one or two of the most frequent such linkages, we make the material more elastic again–and that’s true even if we have no way to remove the other structures at all! Eventually we’ll have a problem again, because the structures that we don’t know how to remove will carry on accumulating so that the overall amount of links will get back to pathogenic levels even if we carry on eliminating the links that we know how to eliminate. But suppose the ones we do know how to eliminate constitute half the total: that means we won’t have this problem until we’re about twice as old as when we currently have that problem. And that’s a very, very long time by the standards of technology: long enough, we can confidently hope, to develop smarter therapies that can break quite a few of the remaining types of link. That would give us another few decades, to develop even smarter therapies… and so on, ad infinitum.

We will need keep one step ahead of the problem for all seven major categories of age-related damage–but I think we can, once we’ve got them all to the point of giving us 30 extra years of healthy life. The bottom line, therefore, is that if you’re still reasonably healthy when those 30-year-conferring therapies arrive, you probably won’t need to die of old age at any age–you’ll be able to remain both physically and mentally youthful indefinitely, dying only from accidents and such like, even though the therapies that will make that happen will only be arriving gradually, over many decades or even centuries.

“Escape velocity” is not a precisely correct description of this, but I find it gets the concept across.

What does all that have to do with nanotech, and why should you care? Well, I think the first therapies, the 30-year-conferring ones, will probably not involve nanotech at all: I think we’ll get there before nanotech becomes sufficiently sophisticated. But as I’ve explained, the problems to be solved will get progressively harder as time goes by, and we can’t afford to slow down–if any of those seven types of damage reaches pathogenic levels, it’s game over. I think it’s quite likely that pure biotechnology will come up against some brick walls by the time we get out to ages like 200 or 250. At that time, we’ll need machinery that’s fundamentally different from enzymes and vaccines and such like, let alone pharmaceuticals: machinery that we can control as precisely as we control computers.

Nanomedicine will need to be at the heart of all medicine by then, but especially at the heart of life extension medicine. And if we relax today, thereby delaying the advent of full-blown molecular manufacturing, you and I may pay for it with our lives in the year 2163.

Aubrey de Grey Ph.D. is a biomedical gerontologist, a Fellow of the IEET, the Chief Science Officer of the SENS Foundation and editor of Rejuvenation Research.

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