A comic once stated that “everyone wants to live forever, but no one wants to be old.” Largely true, I fear, on both counts. The continuing American obsession with cosmetics and surgeries designed to give an appearance of youth has been so thoroughly commented upon that I won’t do more than mention it; the question remains, is it possible to extend actual youth and life span significantly?
Apparently, it is. Aubrey de Grey, Cambridge-educated biomedical gerontologist and director of the California-based SENS (Strategies for Engineered Negligible Senescence) Foundation, recently stated that he believes that the first person who will live to be 150 years old has already been born, and the first person who will live to 1000 will be born within the next twenty years. His team is currently working on a suite of therapies that focus on reversing cumulative cellular damage -- the culprit behind many of the diseases that eventually kill a lot of us, such as heart disease, dementia, and some forms of cancer.
"I call it longevity escape velocity -- where we have a sufficiently comprehensive panel of therapies to enable us to push back the ill health of old age faster than time is passing," de Grey told Reuters in an interview last week. "And that way, we buy ourselves enough time to develop more therapies further as time goes on. What we can actually predict in terms of how long people will live is absolutely nothing, because it will be determined by the risk of death from other causes like accidents, but there really shouldn't be any limit imposed by how long ago you were born. The whole point of maintenance is that it works indefinitely."
De Grey's statement is looking less and less like science fiction. A recent study showed that by manipulating only two genes, it was possible to extend the average life of yeast cells by a factor of ten – comparable to altering humans to allow them to live 800 years. If you’re thinking, “hey, wait, that’s yeast; they’re simple single-celled life forms. How can we extend that to humans?” you should keep in mind that yeast, like humans, are eukaryotes. The two species, however different they appear, have a remarkable overlap in genetics (of the six kingdoms, animals and fungi are the two which are the most closely related in the cladistic sense). Most relevantly, the two yeast genes that the scientists manipulated also exist in humans, and apparently have a similar function in both organisms -- preventing senescence.
Now, I hasten to add that no one is claiming that a gene knockout procedure which extends yeast life spans by a factor of ten will have exactly the same effect in humans. It’s merely suggestive that the possibility of significantly extending human life span exists. As I continually harp upon in my AP Biology class, the developmental genes – which are the ones largely associated with aging – are notoriously dangerous things to mess about with. There’s a constant tightrope-walking that the genetic substructure of the body undergoes. If the developmental genes shut off too early, or too completely, the body becomes unable to heal itself and ages much more quickly. If they stay active too long, it increases the risk of cancer. (This is a significant oversimplification, but it highlights the fact that almost never can you alter a single factor in the body genetically – the vast majority of genes are pleiotropic, meaning one gene locus with many functions.) The recent discovery that carrying the allele for Huntington’s disease (which dooms you to a lingering death by debility and neural degeneration) almost completely eliminates your risk of cancer highlights that fact.
But consider if they could do such a thing. The mechanisms which control aging, physical growth, sexual maturity, emotional maturity, and intellectual maturity all seem to be relatively independent of one another; so think of a world where you reach your adult height at 18, your sexual maturity at 15 or 16, your emotional and intellectual maturity in your twenties… and then you go into a kind of stasis. A thirty year old and a three hundred year old would look, and feel, substantially the same. You don’t really start to age until you are 500 or so. Barring accidents, you would live to see your far distant descendants. Birth rates might not increase that much (women would probably still become menopausal in their forties, as this is a separate genetic construct from aging) but death rates would plummet. Population growth would skyrocket. You think that the Social Security and retirement systems are in crisis now? On the other hand, people would probably not want to retire in their sixties – they’d still have hundreds of healthy years' worth of contributions to make. (On the other hand, in my own case the prospect of teaching biology in the same classroom for the next 600 years falls into the "just shoot me" department.)
It would require a complete restructuring of society, not to mention a complete restructuring of how we personally look at life. What would you do if you knew that you had, not forty or fifty more years of potential good health and vigor, but 400 or 500 years? It would slow us all way down, not just physically but emotionally. No need to rush; you have time. It reminds me of the line from one of the old Star Trek episodes, from a character who was essentially death-proof; “Immortality consists largely of boredom.”
Of course, there’s the pessimist in me that feels like even if this becomes possible, we’ll get our comeuppance. Cancer, if not unknown, was at least far less common before 1800, because infectious disease generally got people before they’d lived long enough for cancer to set in. When infectious disease was largely eradicated, at least in the first world, in the 19th and early 20th centuries, cancer rates jumped because (among other things) we were not dying of other causes quite so much. You have to wonder what new and devastating diseases might occur if we push the life span a lot further than we already have.
So, the inevitable question arises in my mind as to what I'd do if such a therapy were offered to me. Honestly, I have to say that if the risks were sufficiently low, I'd probably go for it. I'm not particularly afraid of dying, but I hate the thought of aging -- the insidious physical and mental weakening, the loss of vigor, and (especially) the eventual dependence on others. If I could put that off for a few hundred years? Yeah, no question about it.
It's not, however, without some ethical qualms. Decisions made in self-interest aren't, sometimes, in the best interest of the world as a whole, and the social and environmental outcomes if such a therapy became widely available are mindblowing. So, the bottom line is that I’m not anxious to die, myself, but the whole thing has me worried. I’m not particularly enjoying aging, but I’m not sure that the alternative might not be worse.