Coming:
Longer Life Spans
By
SENATOR ALAN CRANSTON
The Old testament set the length of man’s natural life-span at threescore
years and ten, of fourscore “by reason of strength.” Some 3000 years later, Elizabethan scholar Francis Bacon saw no
reason to update the figure. “From the
time of Moses to these our days the term of man’s life hath stood about
fourscore years of age.”
Neither Bacon nor the Old Testament sages confused
that 80-years “term” with life expectancy.
A lucky few might live 70 to 80 years if they survived the army of
diseases that preyed on infancy, youth and middle life. But life expectancy—the time a person would
live if he had average luck—was a different matter. In the Bonze and Iron stages, encompassing Old Testament times,
it was about 18 years. And in Bacon’s
time it was below 35.
Today, medical advances have more than doubled life
expectancy in the world’s wealthier nations.
In this century alone (almost entirely through the eradication of
diseases of the young) more than 20 years have been added to the average
American’s life—now about 74 years for women and 70 for men. Nevertheless, most people feel that life
span is a different matter—fixed, constant, forever beyond human tampering and
medical intervention.
I am convicted they are wrong. New developments in gerontology, the science
of aging, suggest that one day soon we will be able to push our natural span
beyond the limits so long considered immutable.
In 1973 I conducted Senate hearings at which
scientists discussed the possibility of people enjoying health and mental
vitality beyond the age of 100. When
the hearings were over and Congress has set up a National Institute of Aging
within the National Institutes of Health, I conducted to keep in touch with
developments in the field. Regularly, I
invite groups of gerontologists and biomedical experts to informal sessions in
my Capitol office.
What I learn from these encounters is
mind-blogging. Researchers across the
nation are probing ever deeper into the mysterious biological
activity—breakdown and mutation in cells and molecules—that we call the aging
process. They have already convinced a
majority of gerontologists that we will be able to restructure the human aging
process to our own benefit. The
question is not whether we will be able to control aging but when.
In the United States, medical science has already
pushed life expectancy very close to life-span figures by destroying
disease. But the limits are not far
ahead. National life expectancy, which
jumped 17 years between 1900 and 1950, inched up a mere three in the next
quarter century. The last appreciable
gains we can expect will come when cancer and cardiovascular disease, today’s
deadliest killers, are finally tamed.
Yet, even in a world liberated from cancer, heart
attack and stroke, old people will continue to die (even if a little later)
from the cumulative physical and mental collapse we call old age. And what if killer diseases are eliminated
but no remedy is found for the degenerative processes of old age. We could be faced with a mushrooming
population of dependent old people.
The prospect of life prolonged—but not enhanced—by
dragging out its darkest years is chilling.
Fortunately, the aim of gerontologists is not mere prolongation of life;
it is the prolongation of life’s most productive, satisfying years. “Old age itself will not be longer, only
later,” says British gerontologist Alex Comfort, “from 80 to 90, say, instead
of 70 to 80.” Or, as science writer
Albert Rosenfield defined it, gerontology’s basic goal “is to keep people fully
functional and in possession of all their faculties until very end.” If gerontologists can pinpoint whatever it
is that triggers and regulated its speed, the ability to extent human life and
its good years will be in their grasp.
How close are they to this goal? Scientists already posses the ability to
extent life—and have done so repeatedly in experiments on laboratory
animals. But they are not certain just
how the experiments worked. Although
they have manipulated the aging process, they have so far failed to define it.
But theories of aging are beginning to coverage in
the notion that every living creature within it a biological “clock” that
genetically programs the rate at which the organism will age. As this clock ticks on, cells mysteriously
loose their immunity to invasion and disease, their vitality ebbs, and
eventually—along with the rest of the organism—they die.
Some researchers have suggested that the clock of
aging is located in genetic material housed in the nucleus of every cell. Others believe it may operate through the
release of s-called death hormones” that remorselessly wear down the body’s
maintenance-and-repair cells. It may
have multiple locations) cellular nuclei), or it may operate from a master
control center such as the hormone-producing pituitary gland. Though the clock’s location remains elusive,
researchers claim its existence is confirmed every time their experiments
successfully manipulate the aging rate in animal cells.
Denham Harman, University of Hebraska biochemist,
believes aging result from wear and tear inflicted by “free radicals,”
broken-off cellular debris that clusters on cells, clogging of “rusting” them
and ultimately putting them our of action.
Herman’s experiment indicated that diet and antioxidant compounds such
as vitamin E would offset free-radical damage.
In the rests he administered, the lives of laboratory rats were
considerably lengthened.
Another supporter of the free-radical theory,
Richard Hochschild of the University of California at Irvine, reports a series
of experiments with mice, age 70 in human terms, were given substances that
help to repair the membranes after free-radical damage. The mice lived an average of 49 percent
beyond their natural life spans.
Believers in hormone-triggered aging point to
laboratory successes of their own.
Removing or retarding the action of certain glands has altered the aging
process in test animals—often dramatically—.
For instance, removing the fish’s adrenal gland has eliminated the rapid
spawn-age-and-die cycle in Pacific salmon.
Gerontologist W. Donner Denkla removed the pituitary glands from the
brains of aged rats, then administered thyroxin and other vital hormones. Close monitoring showed that a variety of
the rats’ body functions had returned to “juvenile competence.” Their coats were again thick and glossy,
their movements quick and energetic.
The rats showed no signs of age or debility until almost at the point of
death.
No doubt the methods to these biomedical pioneers
will one day seem absurdly primitive.
But even these first steps have yielded effective techniques and drugs,
already in limited use on humans in the treatment of advanced senility and
otherwise incurable genetic disorders.
As methods are refined and targets narrowed,
gerontologists may be able to reset man’s biological clock with precision to
stretch out the young and middle years and minimize the period of decline
leading to death. We are on the brink
of a major leap forward in medical science—nothing less than a profound
redefinition of human life.
How soon? An
optimistic few believe we may hold the keys of life-span extension before the
end of the century. Others speculate
that even without mastering all the secrets of aging we will learn enough to
achieve major clinical breakthroughs in the next few decades (much as we
practiced vaccination long before we understood the hows and whys of
immunization). Onesuch breakthrough
would be elimination of the remorselessly slow degenerative aliments of old
age; people would live free of illness or infirmity right up to the end of
their span and then, with little advance warning, simply die.
Luck as well as individual and collective brilliance
will determine whether or not our children or we will inherit the life-span
revolution. The rate of progress also
hinges on availability of funds and the scope of the programs we launch. “The control of the human rate of aging is
going to happen,” says Alex Comfort.
“How soon it will happen depends upon the social pressure for research
and the wisdom with which that research is applied.”
All too many promising leads and experiments are
shelved for want of funds or public interest.
One reason is simply the credibility gap surrounding the notion of an
increased life span. Another is the
reluctance of institutions to nurture ideas that challenge established
assumptions or that fail to guarantee a return on investment.
In 1979 the federal government spent nearly $900
million in cancer research and almost $500 million in heart-and lung disease
research. Not everyone, fortunately,
suffers from these diseases. But
aging—the one affliction that affects all of us—will get about $37 million for
federally sponsored research. Much of
that will go for social, psychological and statistical studies of the
elderly. Only a portion will finance
biological studies of the aging process—and just the smallest fraction of that
will finance research aimed at extending life span.
Are we dragging our feet because we are afraid? Could we be thinking of the strain that even
a ten-years increase in life span would put on our overburdened social welfare
and health services? We should think
again. When our productive years fill
out most of our life span, the social and economic dependence of age will be
diminished problem. With age freed of
its present stigma and infirmity, society might at last profit from the wisdom
and experience we now thoughtlessly throw away.
