A self-professed “troublemaker,” Aubrey de Grey works to scrutinize and encourage work in human longevity. De Grey, 40, is a theoretical biologist and biogerentologist at the University of Cambridge in England.  He is a cofounder of the Methuselah Mouse Prize, “a contest designed to accelerate progress toward real longevity-enhancing medicine, promote public interest and involvement in research on healthy life extension, and encourage more such research.” Technology Review spoke to de Grey as he attended a conference on gene therapy in Santa Barbara, CA.

TR: You believe that tripling the remaining lifespan of two-year old mice is as little as 10 years away.

De Grey: That’s right, with adequate funding. The sort of funding that I tend to talk about is pretty modest, really-less than the amount the United States already spends on the basic biology of aging. I’m talking about a maximum of  $100 million per year for 10 years. With that sort of money, my estimate is we would have a 90 percent chance of success in producing such mice.

TR: How could this apply to the general human population?

De Grey: My argument says that if you’re young enough, and we fix human aging soon enough, then we will be able to extend your lifetime to 150 years. Then basically we’re going to be able to get you out to infinity, depending on your not walking in front of buses and stuff like that.

TR: Infinity?

De Grey: The argument is extremely simple: it just says we see how fast science advances, and if we got to the point where we could take middle-aged humans and triple their remaining life expectancy, so someone who’s in their 50s and they’re normally going to die in 30 years-well, we can take that out another 50 or 60 years on top of that.

TR: How does it look for the current generation?
 
De Grey: People of my age, we’re on the cusp. If things go well, then things could be in time for me. If things don’t go well, things won’t be in time for me. Even if a cure for aging happened a year sooner that it would have done if I had not been involved in this field, then I would have essentially saved 30 million lives, which is a pretty big deal. That appeals greatly to me, and so I really don’t worry too much about if my life is going to be among them.

TR: Would you care to guess what the lifespan of someone born in the year 2025 will be?

De Grey: The number I usually put on that is 5,000 years. But this, I want to stress, is an absolute finger in the air. The way I calculate it is as follows. If aging already didn’t exist but we did have all the other causes of death at the rates we have them now-infectious diseases that kill young people, car accidents, wars-then basically you come out 1,000 years that people would live on average, plus or minus a few hundred. I tend to say it will be more like 5,000 years simply because when society is faced with the opportunity to live an arbitrary length of time, we will become more risk averse. I predicted in 1999 that driving would be outlawed, because it will be too dangerous to other people. I still think that’s likely, unless we design cars that are much safer and can avoid serious accidents even in the case of severe human error.

TR: 5,000 years? That seems pretty outlandish.

De Grey: I get that reaction a lot-my estimate gives people the conceptual bends. But if you go through the logic step by step, you’ll see that it’s virtually inevitable that we will attain that sort of life expectancy in that sort of timeframe, just so long as two things work out. First, we will have to develop first-generation rejuvenation therapies by 2050 or sooner. Secondly, the value we put on life will have to rise as our anticipated lifespan increase, which has happened in the past. I’m not a sociologist, but I think this second development is very likely, given the first.

So, what remains for me to explain is why the development of first-generation rejuvenation therapies-which I’ll define as ones that can be applied to people in their 60s and increase their lifespan by at least 30 years-is enough to give people who are 25 or younger at the time those therapies arrive a lifespan not limited by aging in any way. The answer can be given in one word: bootstrapping. Thirty years is an absolute eternity in science, so it is nigh on inconceivable that the second-generation therapies (which, let’s say, give another 30 years on top of what the first-generation ones give) will be so long in coming that the beneficiaries of first-generation therapies will miss out on them. And of course the same applies to subsequent-generation therapies ad infinitum.

Another way to see how wrong it is to regard such a trajectory as crazy is to ask how fast mortality rates at current old ages (say, between 50 and 80) would have to fall in order to have people get physiologically younger with time-that is, to have their risk of death in the next year be lower than it is this year despite their being a year older. That turns out to be only about ten percent per year, which is only about three times the peak rate of decline of infant mortality seen in industrialized countries in the 20th century.

TR: How has your background in computer science and engineering influenced your work?

De Grey: This is very important, not just for myself but for the field in general. It’s a very bad thing in biology that there are so few people doing the sort of work that I do, not just in the biology of aging but in biology as a whole-doing theoretical work, analyzing other people’s data, pacing up and down and thinking a lot and reading a lot. Experimental scientists don’t have time to read very much, because experiments are very time consuming if you want to do them right. You want some people doing the theory and some people doing the experiments. This is well understood in other areas of science, especially in physics. But in biology this balance has been lost, and I think it’s to the detriment of the field.

Technology Review: You believe that when a state of “engineered negligible senescence” -essentially, unlimited lifespan-arrives in humans, there’ll be no debate about whether we should pay for it.

Aubrey de Grey: I assure you that that as soon as we get anywhere near that, even in mice, there will cease to be a debate as to whether we should spend money on this. One of the things that worries me the most is that people who think about these things, about the desirability and the economics and social consequences, tend to assume that we don’t need to worry about them until the technology is already developed for humans, and probably not until the technology has become relatively affordable and relatively widespread. That could not be further from the truth.

TR: How so?

De Grey: The problem that’s going to happen is there’s going to be absolute total pandemonium as soon as this technology becomes widely anticipated, even if that anticipation is actually overoptimistic in terms of time scales. And that will happen as soon as we get really impressive results in mice.