Why die? There may soon be nothing preventing great-grandparents from being as agile in body and mind as their descendants are.Sections
Can Aging Be Cured?
Shaping Up for Long Life
A World without Aging
Keywords: ageing, biogerontology, geriatrics, gerontology, immortality, life-extension, old age, rejuvenation
Imagine that your grandmother looks like a teenager, plays soccer, parties at the clubs all night, and works as a venture capitalist. Or imagine your grandfather teaching you the latest high-tech computer software in his office, which you hate to visit because of the loud heavy metal music. Such a scenario is hard to envision because we are taught to accept aging and the resulting suffering and death as an immutable fact of life. We cannot picture our grandparents in better physical shape than we are. Nonetheless, aging may one day become nothing more than a scary bedtime story, perhaps one your grandfather will tell your grandson after a day of white-water rafting together.
Can Aging Be Cured?
Aging is a "barbaric phenomenon that shouldn't be tolerated in polite society," says University of Cambridge gerontologist Aubrey de Grey. However, the more than 50% increase in longevity of the past century was due mainly to advancements in the war on infectious diseases, not aging. Present anti-aging treatments do not slow the aging process and do not extend lifespan more than quitting smoking, exercising, eating a good diet, or heeding ordinary medical advice. The only way to achieve another 50% increase in human longevity is by discovering ways to retard the aging process itself.
Although human aging remains a largely mysterious process, and scientists still debate why we age, there are reasons to think human aging can be manipulated, maybe even cured like a disease. Not only some animals live much longer than humans--recent estimates that bowhead whales may live over 200 years are a good example--but several higher animals appear not to age. None are mammals, though, but examples include vertebrates such as certain turtles that do not show signs of aging even after decades of study. While the reasons behind the apparent absence of aging in these species remain a subject of debate, they show how Nature has already devised ways to make animals live much longer and age slower than humans. Like the Wright brothers and other early flight pioneers conducted detailed observations of birds and were inspired by them, so can we be inspired by how aging is much slower, and maybe even absent, in certain animals. Now the challenge for biomedical research is to do the same in humans.
In recent years, many advances in anti-aging science have been made at the cellular level. Normal human cells have a built-in program that prevents them from replicating more than a predetermined number of times. Using the enzyme telomerase, it is possible to genetically modify human cells to overcome their programming and make them divide indefinitely. Drugs targeting telomerase are also being developed, even though telomerase alone does not solve the aging problem: Mice genetically modified to produce lots of this enzyme do not live longer. Still, as detailed elsewhere, telomerase and similar findings observed in simple model organisms like yeast showcase that aging at the cellular level can be stopped.
Genetic engineering can more than triple the longevity of worms and increase by almost 50% the lifespan of flies. Results are also promising in mammals: Scientists have extended longevity in mice by up to 50% through genetic interventions. If such outcomes could be achieved in humans, then it would come to be normal to have grandparents more than 120 years old. Several companies and academic research groups are conducting research aimed at retarding aging by targeting genes and pathways shown in model organisms to regulate aging. If the breakthroughs of recent years are anything to go by, it is likely that we will see several-fold longevity increases in mice within the next decade or so.
Achieving similar results in humans will be harder: Scientists have already identified genes that appear to accelerate human aging, but they have yet to find genes with the opposite effect. Variants in human genes have been shown to have modest effects on longevity. With the sequence of the human genome and the decreasing costs of sequencing more genomes, we are now in a better position to find out more about the genetics aging in animals as well as in humans. Drawing from the technological breakthroughs of the past 10 or 20 years, researchers are likely to develop methods to considerably delay human aging within the next few decades. "The prospects of dramatically increasing human longevity are excellent," declares Professor Steven Austad, of the University of Texas Health Science Center.
Although some scientists argue that aging will never be cured and our grandparents will continue to fit our stereotypes, many others remain confident we will soon learn how to modulate the human aging process. "I believe our generation is the first to be able to map a possible route to individual immortality," says William Haseltine, former CEO of Human Genome Sciences Inc. in Rockville, Maryland.
Shaping Up for Long Life
One method available today might delay human aging: Caloric restriction, which simply means a diet with fewer calories that still delivers the required nutritional content. Experiments have shown longevity increases of more than 50% in certain mammals and other beneficial effects, but most people find it hard to stick to such a diet and there are negative side-effects. If science is to extend human longevity, it will have to do so by extending the healthy lifespan while preserving youth and vitality, not by prolonging the time spent in age-related disability. The extra years must allow future grandparents to enjoy life rather than just cling to it.
It is unlikely, but possible, that a cure for aging and associated age-related diseases will appear suddenly. Since scientists have already developed new genetic interventions to delay aging in animals, therapies aimed at human aging are expected to gradually progress in power and efficiency. If a therapy could slow human aging by 50%, for instance, we would have 30 or 40 more years of life. In that time, new discoveries could be made that would allow us to live even longer. The cycle could continue until a true cure for aging was discovered. "It's possible that some people alive now may still be alive 400 years from now," claims gerontologist Michal Jazwinski of Louisiana State University Health Sciences Center. But what would be the consequences of extended human longevity or a real cure for aging?
A World without Aging
Suppose that we eliminate a majority of age-related diseases, such as cancer and heart disease, and can maintain the vitality of the body indefinitely. Under these circumstances, everyone can expect an average lifespan of more than 1,000 years and a virtually unlimited maximum lifespan. Estimating a future average lifespan of 1,000 years is based on removing age-related mortality from current statistics: accidents and other causes of death still remain, of course. Aubrey de Grey believes that human life expectancy at birth in 2100 will be 5,000 years, however. He takes into consideration not only anti-aging discoveries but also changes in technology and attitudes as people strive to reduce or avoid risk and make dangerous activities safer.
Our first instinct when we consider a world without aging might be a concern about overpopulation. Yet we cannot see breakthroughs in aging research as isolated events. Technology evolves; civilization evolves. For example, worldwide agricultural output has more than doubled in the past 50 years. In fact, future problems resulting from overpopulation have been widely touted for decades, most famously in the 1970s ("Mathusianism"). These warnings have always proven wrong, as the proponents did not account for advances in food, energy, transport and renewable technology. Of course overpopulation in some regions, such as the southeast Asia, might be aggravated by life extension technology. Even so, letting people suffer and die of aging or disease to control overpopulation is repugnant and ethically unacceptable, so other solutions must be sought--and humans have a History of finding solutions.
Another issue related to an unlimited lifespan is the ability of a 200-year-old human to absorb new ideas. If not, we would have age differences in the mind instead of age differences in the body, which could lead to cultural stagnation. As German physicist Max Planck once put it, "A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents die, and a new generation grows up that is familiar with it."
There is also the danger that people considered threats--someone like a Stalin or a Fidel Castro--will remain in power much longer than they would if they faded away or died because of aging. Prisoners convicted of violent crimes would eventually be released and, as they would keep young bodies, could continue to pose a threat. A more in-depth discussion of possible concerns of curing aging is included elsewhere.
Delayed aging will lead to huge social changes, and perhaps even to some bizarre possibilities: your children dating your grandparents' friends, for example, or your children looking younger than your great-grandchildren. Age stratification in the population will change or disappear, and with it, many of our preconceived ideas. But civilization continually evolves to encompass new ideas and new possibilities. Most important of all, in defeating aging we will have eliminated one of the greatest causes of suffering, pain and death.
Elderly people in an aging-free tomorrow will be extremely productive, changing careers from time to time throughout their lives. They will have the experiences of a lifetime--or two lifetimes, or three, or twenty--combined with a young physique. The burden of age-related diseases on health care will disappear. That is why the grandparents of tomorrow will live longer and happier lives. You and I are the grandparents of tomorrow. With hard work, scientific research, anti-aging advocacy and a bit of luck, we may be around for centuries to come.
Notice: This article is an adapted and updated version of "Winning the War Against Aging," originally published in the March-April 2003 issue of THE FUTURIST. Used with permission from the World Future Society, 7910 Woodmont Avenue, Suite 450, Bethesda, Maryland 20814. Telephone: 301/656-8274; Fax: 301/951-0394; http://www.wfs.org
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