LIFE WITHOUT DEATH
Duncan Turner says scientists now believe
that we can live to be 160 — even 300 but there may be a price to pay
EVERY year millions of people suffer from a mysterious syndrome. Patients gradually lose their ability to regenerate body tissue, their muscles waste and their skin loses elasticity. They become infertile, and most report a reduced sex-drive. Orthopaedic disorders and progressive damage to the sense organs and central nervous system are also common. This syndrome is closely related to disorders such as Alzheimer's, Parkinson's, cancer and cardiovascular disease. It is called ageing.
Until recently, the thought that there might ever be a cure for ageing seemed preposterous. Growing older and more decrepit appeared to be an inevitable and necessary part of being human. Over the last decade, however, scientists have begun to see ageing differently. Some now believe that the average life-expectancy may soon be pushed up to 160 years; others think that it may be extended to 200 or 300 years. A handful even wonder whether we might one day live for a millennium or more.
Behind this new excitement is the theory that the primary cause of ageing lies in highly reactive molecules called free radicals, left behind by the oxygen we breathe. Free radicals react with the molecules in our bodies, damaging DNA, proteins and other cell tissues, and are known to be implicated in diseases as diverse as cataracts, cancer and Alzheimer's. The body does its best to protect itself against free radicals with antioxidant chemicals, such as vitamins E and C, and with antioxidant enzymes, such as superoxide dismutase, but it is always fighting a losing battle.
A year ago Gordon Lithgow of the University of Manchester discovered a way to help combat free radicals. Using a synthetic antioxidant, designed to mimic superoxide dismutase, he managed to increase the lifespan of nematode earthworms by 50 per cent. Despite cautionary words from the scientists, many hailed this as the first step towards an elixir of life. Research involving the mutation of genes has also thrown up fascinating results: after identifying two of the genes that appear to control how long the nematode worm lives, homologues of these genes were found in organisms as various as fruit-flies, mice and human beings. When one considers the vast evolutionary distances that separate these species, it suggests that we may have discovered a key to how ageing is regulated throughout the entire animal kingdom.
In June last year a small American company called Eukarion sought permission to carry out the first trials of an anti-ageing drug, SCS (synthetic catalytic scavengers), on human beings. Although it will initially be used to help stroke victims and treat diseases associated with old age, Eukarion said, that 'if the effect of treating diseases of old age is to extend life, everyone's going to be happy.'
Some scientists, however, are quick to quell extravagant speculation. 'There is no evidence whatsoever that ingestion of any chemical would have an effect on mammals,' says Rich Miller of the University of Michigan. And those people who claim it might need to go out and do some experimenting.' Some research, moreover, has produced alarming results. As well as controlling ageing, the genes in question determine hormonal pathways that signal to the receptors for insulin and insulin-like growth factor. The upshot of this is that although mutant mice can be made to live up to 80 per cent longer, their pituitary glands are defective and their growth is stunted.
Quite apart from these sorts of horrors, the ethical implications of extending human lifespan are likely to fill many with trepidation. Even if the falling birth-rates reported in the world's developed nations were to be duplicated across the globe, would this be sufficient to compensate for massively extended life-expectancy, and would we be willing to see the demographic balance of our society change out of all recognition? David Gems, the head of the Centre for Research into Ageing at University College, London, enthuses about the opportunities opened up by extended life, but even he observes, 'If people live much longer, the proportion of children would, of course, be very small. It strikes me that it might feel rather claustrophobic: all those middle-aged people and very few children or young people.'
There are also economic considerations. One might expect the retirement age simply to be pushed back by a decade or three and for the economy to expand as the number of dependants, children and pensioners became a much smaller proportion of the overall population. Unfortunately, our experience is of just the opposite. In today's world, more and more workers are laid off well before the existing retirement age of 65, and these are most frequently those with insufficient private means to support themselves.
The Christian ethicist and philosopher of science, the Revd John Polkinghorne, emphasises that any discussion of the merits of life-extending therapies must take into account the quality of the life that is lived: 'One would not wish to prolong life beyond the point it had ceased to be creative and fulfilling and meaningful,' he says. Presumably, there would have to come a point at which life ceased to be creative and became just repetition. Clearly, there are only so many rounds of golf one would want to play.'
But Polkinghorne, a member of the Human Genetics Commission, also observes that so far our experience of extended life-expectancy has not resulted in world-weariness. Throughout the last century, life-expectancy rose consistently, thanks to improved diet, better hygiene, continuous medical innovation and the provision of free or subsidised healthcare. In 1952 the Queen sent out 225 telegrams to people on their 100th birthday; in 1996 she sent out 5,218. 'Consider also, the lives of our Roman and Anglo-Saxon ancestors,' he says. 'By and large, the doubling of human lifespan we have seen since then has not been a bad thing. Life has not become frustrating and boring. For example, we now live to see our children's children, and this is good.'
John Harris, another member of the commission, has recently been turning his thoughts to imagining a world in which ageing was finally a thing of the past and the average life-expectancy was as much as 1,200 years. Harris finds the prospect of being a latter-day Methuselah attractive and warns us not to confuse what is good with what is merely familiar: 'The present situation with a generation of x million people succeeded by x million people succeeded by x million people is not necessarily better or more ethical than one in which the same x million people live on indefinitely.'
Moreover, as Harris observes, despite our reservations, if the initial breakthrough were to be made, progress in anti-ageing science might well be inexorable. 'In theory, [the government} can regulate — or indeed ban it, as we have seen with reproductive cloning. In reality, technologies that are found to be useful prove to be inevitable in the end. My guess is that, if there are these therapies, they will prove unstoppable, because [extended life-expectancy] would be so attractive to those with the power and money to avail themselves of it.'
Previous page
