Friday, September 24, 2010

SciAm Article on Aging

The Sept issue of Scientific American is a special issue on "the end". It includes this fascinating article by one of the leading experts on aging. Here are a few excerpts:

IF YOU WERE GIVEN a free hand to plan how your life will end—your last weeks, days, hours and minutes—what would you choose? Would you, for example, want to remain in great shape right up until the last minute and then go quickly? Many people say they would choose that option, but I see an important catch. If you are feeling fine one moment, the very last thing you would want is to drop dead the next. And for your loving family and friends, who would suffer instant bereavement, your sudden death would be a cruel loss. On the other hand, coping with a long, drawn-out terminal illness is not great either, nor is the nightmare of losing a loved one into the dark wastes of dementia.

We all prefer to avoid thinking about the end of life. Yet it is healthy to ask such questions, at least sometimes, for ourselves and to correctly define the goals of medical policy and research. It is also important to ask just how far science can help in efforts to cheat death.

....By far the majority of natural organisms die at relatively young ages because of accidents, predation, infection or starvation. Wild mice, for example, are at the mercy of a very dangerous environment. They are killed rather quickly—it is rare for a wild mouse to see its first birthday. Bats on the other hand are safer because they can fly.

Meanwhile maintenance of the body is expensive, and resources are usually limited. Out of the daily intake of energy, some might go to growth, some to physical work and movement, some to reproduction.

....Here is where the disposable soma theory comes in. The theory posits that, like the human manufacturer of an everyday product—a car or a coat, for example—evolving species have to make trade-offs. It does not pay to invest in allowing indefinite survival if the environment is likely to bring death within a fairly predictable time frame. For the species to survive, a genome basically needs to keep an organism in good shape and enable it to reproduce successfully within that time span.

....Using the science of aging to improve the end of life represents a challenge, perhaps the greatest yet to face medical science. Solutions will not come easily, despite the claims made by the merchants of immortality who assert that caloric restriction or dietary supplements, such as resveratrol, may allow us to live longer. The greatest human ingenuity will be needed to meet this challenge. I believe we can and will develop treatments targeted at easing our final years. But when the end arrives, each of us—alone—will need to come to terms with our own mortality. All the more reason then to focus on living—on making the most of the time of our lives, because no magic elixir will save us.