Aubrey de Grey, advocate for radical life extension and originator of the Strategies for Engineered Negligible Senescence (SENS) research programs, has derived a great deal of mileage from his assessment that it is possible to achieve life spans of 1000 years or longer, as illustrated in the brief interview below. Life spans of centuries and longer can be achieved by progress in biotechnology sufficient to bring aging under medical control, but the important point is that this progress doesn't have to happen all at once. For so long as the early rejuvenation therapies are good enough to add a decade or two of healthy life, that gives additional time to improve those therapies and obtain access to greater and more efficient means of rejuvenation. A tipping point of actuarial escape velocity is reached and remaining healthy life spans increase at a faster pace than one year of additional life expectancy with every passing calendar year. For there onwards, life expectancy is no longer limited by aging and disease.

Could Human Beings Live For 1,000 Years?

What have been the major advances at SENS and why haven't life-extension programmes gone mainstream yet?

Over the past two years we've had a slew of breakthrough publications in journals such as Science, Nature Communications and Nucleic Acids Research that reported key advances against the most intractable components of aging. It's no exaggeration to say that in at least a couple of cases we have broken through logjams that have stalled key areas for over 15 years. You may feel that eight years is a long time to be only making such preliminary, step-one breakthroughs, but you'd be wrong - step one is always the hardest, and that is why nearly all research, whether in academia or in industry, is immensely biased towards the low-hanging fruit and against the high-risk high-reward work that is so essential for long-term progress. We exist as an independent foundation for precisely that reason. But, saying that, I must also stress that we are already showing great success in taking enough steps so that our programmes become investable. The atherosclerosis one was the first of, at this point, five start-ups that have emerged from our projects - covering conditions as diverse as macular degeneration, senescent cells, amyloid in the heart, and organ transplantation.

What are the key therapies that will create a 1,000-year-old human?

It's critical to understand, and yet it's almost universally overlooked, that my prediction of such long lifespans for people who are already alive divides into two phases. The first phase consists of the therapies that SENS Research Foundation is working on right now, along with parallel initiatives that have achieved sufficient traction that we don't need to be their engine room anymore; most importantly, a variety of stem-cell therapies. The other ones are also one or another kind of damage repair or obviation - removing waste products, rendering mutations harmless, restoring elasticity. They combine to restore the molecular, cellular structure and composition of the middle-aged (or older) body, and thereby its function (both mental and physical), to how it was as a young adult.

But that's only the first phase and I have always stressed that I don't anticipate more than about 30 years of additional life arising from it. That's a lot when compared to anything we can do today, but it's not four digits. My prediction of four digits comes from the second phase, which arises from the critical fact that phase one buys time. If you're 60 and you get a therapy that makes you biologically 30, then, yes, you will be biologically 60 again by the time you're chronologically 90. Sure enough, the therapies won't really work any more, because the damage that has made you biologically 60 again is, by definition, the more difficult damage, the damage that the therapies don't repair. But this is 30 years on, and that's an insanely long time in any technology, including medical technology. So, when you're 90 you will have access not just to the same therapies that you had 30 years ago, but to improved ones that can repair a whole bunch of the damage that the first-generation ones couldn't. So they will work. They still won't be 100 percent perfect, but they won't need to be; they will just need to be good enough to 're-rejuvenate' you so that you won't be biologically 60 for the third time until you're chronologically 150 or whatever. And so on.

What is more important in reducing aging: medical therapies, drugs, or lifestyle changes?

I'm all for lifestyle optimisation, but you have phrased your question as a comparison and, for sure, the answer is that lifestyle optimisation can only, ever, make a very small difference - a year or two - to how long we stay healthy and thereby to how long we live. Now, medicines and drugs that we have today are equally modest in their effects, and that's why people die today at ages only slightly older than their parents. But within the next couple of decades we have, I believe, a very good chance to change that scenario completely.

Is anyone testing your therapies at the moment on humans?

Sure, but only a subset of them. Some of the easiest components of SENS are already in clinical trials, such as stem cells for Parkinson's disease. Others, including ones spun out from SENS Research Foundation's research, may get there within a year or two. But some are probably 10-15 years out still. Those ones are just as critical as the easier ones, so we are working as hard as we can to accelerate them, but we're devastatingly limited in that regard by shortage of funds.