Human Immortality: A Scientific Reality?
by Gary Vey for Viewzone

If you're alive in 20 years, you may be able to live forever.

From the moment of birth, we begin the battle against death -- against the inevitable. Statistics say that a newborn child can expect to live an average of 76 years. But averages may not be what they use to be.

In 1786, life expectancy was 24 years. A hundred years later it doubled to 48. Right now, it's 76.

"Over half the baby boomers here in America are going to see their hundredth birthday and beyond in excellent health," says Dr. Ronald Klatz of the American Academy of Anti-Aging. "We're looking at life spans for the baby boomers and the generation after the baby boomers of 120 to 150 years of age."

Today's quest for the fountain of youth is taking scientists from inside the genetic structure of cells to analyzing the role of stress and diet on life spans. Would-be immortals flock to anti-aging clinics and shell out as much as $20,000 a year for treatments that include hormone therapy, DNA analysis, even anti-aging cosmetic surgery. These experimental therapies offer no guarantees -- just the promise of prolonging life.

"Anti-aging medicine is not about stretching out the last years of life." says Dr. Klatz. "It's about stretching out the middle years of life... and actually compressing those last years few years of life so that diseases of aging happen very, very late in the life cycle, just before death, or don't happen at all."

The cause of human aging is now being understood.

The cause of what we call "aging" is now finally being understood. This new understanding may soon move anti-aging cosmetics and surgery to the realm of snake oil and Siberian yogurt as life-extension fads. Just when you thought that holographic TV and outer space travel were the future benefits of modern technology, immortality has silently been revealing itself to scientists like Doctor John Langmore [right] of the University of Michigan's Department of Biology. Dr. Langmore and his group have been looking inside human cells, at the very essence of human life: the DNA molecule. Specifically, Dr. Langmore is looking at the tips of the DNA molecule - a previously overlooked part of the double-helix molecule - that contain a kind of chain of repeating pairs of enzymes.

Telomeres - programmed to die?

Called telomeres, these molecular chains have often been compared to the blank leaders on film and recording tape. Indeed, telomeres seem to perform a similar function in aligning the DNA molecule during the replication process. Protecting the vital DNA molecule from being copied out of synch, these telomeres provide a kind of buffer zone where asynchronous replication errors (that are inevitable) will not result in any of the vital DNA sequences being lost.

Other scientists use the analogy of the plastic bands on the ends of shoelaces. Telomeres seem to hold the important DNA code intact, preventing it from freying as the molecules replicate over time.

Perhaps the best analogy I have heard is to compare the telomeres to the white space surrounging an important type written document. Imagine that this paper is repeatedly slapped on a copy machine, a copy is made, and then that copy is used to make another copy. Each time the paper is subject to errors of alignment. After enough copying it is probable that the white space will diminish and some of the actual text will not be copied. That's what happens to our cells' DNA and is the reason we get old and die.

As any cell gets older, it is under attack by oxides and other so-called free-radical chemicals in the body and environment. We survive as living beings because our cells have the ability to duplicate themselves before being killed by these natural causes. Each time our cells duplicate themselves, the DNA molecule, which resembles a spral ladder, splits along the "rungs" of the ladder. Each half of this "ladder" then rebuilds the missing half making two new DNA molecules. But the procedure is not perfect and usually a small portion of the DNA molecule is lost and not copied. Since errors are more frequent on the ends of the DNA molecule, this area does not contain any important DNA information but rather a series or chain of repeating enzymes. The errors are therefore usually confined to this chain, called a telomere, and so the effect is usually insignificant.

Scientists recently noted that the length of these telomere chains were shorter as we grew older. Eventually, the telomeres become so shortened that the losses in replication begin to effect the vital DNA molecule sequence and prevent the cell from being able to duplicate itself. This point, when the cell has lost vital DNA code and cannot reproduce, is called the Hayflick limit. This is why we age.

Dr. Langmore uses physical, biochemical, and genetic techniques to study the structure and function of telomeres. His group has developed a cell-free system to reconstitute functional model telomeres using synthetic DNA, and are studying the mechanism by which telomeres normally stabilize chromosomes and how shortening of the telomeres could cause instability.

The protein factors responsible for stabilizing the ends of chromosomes are being identified, cloned, and studied. Electron microscopy is used to directly visualize the structure of the model telomeres. His group is also using new enzymatic assays to determine the structure of telomere DNA in normal and abnormal cells grown in vivo and in vitro, in order to address specific hypotheses about the role of telomeres in aging and cancer.

Recently, scientists discovered an important enzyme that can turn the telomere production on the DNA molecule "on" and "off." It's called telomerase. It seems that as we get older, the amount of telomerase in our cells decreases. Naturally, the exploration of this enzyme is now the focus of much investigation, but unfortunately the research is aimed at understanding how to turn telomeres "off" to limit the spread of "immortal" cancer cells.

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