Prime Time - Jane Fonda [141]
“But,” he added, “the reason for doing the research is not be-cause we think that it would actually produce these big increases in human life span. We believe that if we understood why it produces these increases in life span in other organisms we might discover promising therapies in the treatment of metabolic diseases, including obesity, diabetes, cancer, Alzheimer’s, and other diseases of aging.”
The Telomere Hypothesis
Perhaps you have read about the telomere hypothesis of cellular aging. I have already discussed how many of our cells are continually dividing. Every time they divide, the very tail ends of the chromosomes—called the telomeres—become shorter, until the time comes when they are too short to divide anymore. The cells don’t die; they just quit replicating, for reasons nobody understands, and this is called senescence. Some cells that do not go through this dividing and gradual shortening into senescence are the reproductive cells known as the germ line. In these cells, a special enzyme called telomerase shuts off the process of telomere shortening. If you put the telomerase enzyme back into the cell, it puts the DNA back on the end of the chromosome, so that it doesn’t get short. The result is immortality at the cellular level. Sounds like the Fountain of Youth, right? Trouble is, this is also what we call cancer. Tumor cells are immortal cells because they have been released from the telomere-shortening process.
Biomarkers of Aging
The anti-aging medical interests and the nutraceuticals industry issue a lot of promises about tremendous increases in life span and health if you’ll just take the right supplements, human growth hormones, resveratrol, or all sorts of new elixirs. Look at all the longevity spas springing up all over the place. Dr. Sprott explained, “They run a series of tests on you, looking for what they call biomarkers of aging, and at the end of the tests they will tell you that according to those biomarkers you are in pretty good shape except that you have this system and that system that need a little tuning up—for the average cost of $25,000 a year for the rest of your life. What they don’t tell you is that the only thing that is going to change very much is the thickness of your wallet. We just don’t know enough yet. One problem is that National Institute on Aging grants are for a maximum of four years, but right now it takes one hundred and fifty years for scientists to know if an experiment to extend the human life span has worked. Biomarkers of aging could shorten up the whole process because they would show us the rate at which an organism is aging in less than the life span of that organism. Well, I spent a big chunk of my career and a big chunk of NIA’s money searching for the biomarkers of aging, and I can tell you there aren’t any.”
Dr. Sprott feels that a danger of the current promises of longevity is that they are simply not true, and “it encourages the public belief that you can get health out of a bottle; that all you need to do is to swallow a pill rather than increasing your life span and health span by a combination of having chosen long-lived parents and living an appropriate, healthy lifestyle.”
Stem Cells
Many problems that develop with age are not caused by disease or trauma and are difficult to distinguish from the process of aging itself. One example is what is called sarcopenia,