The Prospects for Living Even Longer

THE biology of aging is no better understood today than was the circulation of the blood before William Harvey. "We probably age because we run out of evolutionary program," according to Dr. Alexander Comfort, director of the Medical Research Council Group on Aging at University College, London. "In this we resemble a space probe that has been 'designed' by selection to pass Mars, but that has no further built-in instructions once it has done so, and no components specifically produced to last longer than that. It will travel on, but the failure rate in its guidance and control mechanisms will steadily increase--and this failure of homeostasis, or self-righting, is exactly what we see in the aging organism."

Until recently, Dr. Comfort doubted that these built-in instructions could soon be altered, or the components made to last longer. Because of advances in genetics and molecular biology, however, he now believes that some method to reduce the rate of aging and to extend vigorous life by at least 15 years will be discovered within the next two decades. This extension would be in addition to the roughly five-to-seven-year increase in average life expectancy that will take place when medicine conquers cancer and vascular diseases.

More than 20 different highly speculative theories of aging are now being tested in scientific laboratories round the world. The method or methods by which the human life-span will be extended depend on which of these theories turns out to be correct. Some of them have to do with genetic engineering--attempts to alter the program of the cell by changing the coding on the DNA molecule. But nongenetic theories will probably pay off sooner. One current favorite holds that aging occurs because certain giant molecules in human cells eventually get bound together. These immobile aggregations clog the cells, reduce their efficiency and eventually cause them to die. In Wisconsin, Dr. Johan Bjorksten is trying to find suitable enzymes, most likely from soil bacteria, that will reduce these massed molecules to small fragments that could be excreted from the cells. Such enzymes would probably be injected daily into the body with a hypodermic syringe; if the injections were begun early enough, the result might increase a man's life-span by 30 years.

The "free radical" theory of aging, if proved correct, would probably lead to a simpler method of rejuvenation. Free radicals are fragments of molecules with a high electrical charge--which by their oxidizing properties can cause changes in the body such as hardening of the arteries. An antioxidant, which can be produced cheaply and taken in pills, is supposed to deactivate the free radicals, thereby retarding the aging process. One such antioxidant, BHT, has already dramatically increased the life-span of mice by 50% .

Even today the population over 75 in the U.S. is increasing at two and a half times the rate of the general population. If the average life-span is significantly further increased, the population would indeed become aged, a trend which would be accelerated by a drop in the birth rate. As to vigor, when the breakthrough comes in aging research, people in their 70s and 80s should have the energy of those in their 50s and 60s today. Ideally this would produce a greater number of selfless, highly educated wisemen who could undertake complex new projects for the benefit of mankind. But few believe that it would work this way. Most observers suggest that increased longevity would only magnify today's ambiguities and uncertainties if defining the role of the elderly.

Would vigorous octogenarians keep the reins of politics, business and family finances, frustrating the powerless younger generations? Or would they be pushed out of power and wander around, bitter and disgruntled, unable even to talk the same language as their juniors, like Swift's awful immortals, the struld-brugs? Would conflict between generations supersede hostility between classes and races? How could insurance and pension plans continue payments for decades longer? Will aging control become as vital an issue as birth control? In short, the changes resulting from a drastic extension of the lifespan, or even from a series of life-extending bonuses, may eventually exceed those brought about by splitting the atom or man's voyages to the moon.

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