For the better part of the past decade, life-extension gurus have peddled the notion that our lifespan may be more or less dependent on what sort of intracellular activity is taking place on the tips of our chromosomes. That’s where a protective cap, called a telomere, stands guard, so to speak. Every time a chromosome cell divides, however, that guardian can lose a bit of its stature. If it gets too short, we’ve been told, the cell it’s protecting dies. When cellular deaths outpace cellular births, accelerated aging ensues.
For reasons a cellular biologist could explain more clearly than I can, young people tend to sport lengthy telomeres and the elderly are often saddled with squat ones, a discovery that no doubt brightened the horizon for longevity scientists who set out to find ways to stretch them out — and thus profitably extend people’s lives. Back in 2015, for instance, Helen Blau, PhD, and her team at Stanford’s Baxter Laboratory for Stem Cell Biology made headlines after they were able to lengthen the telomeres in a set of cells by injecting a certain enzyme.
“It might not be the Fountain of Youth to keep us young forever, but this discovery is a real shot in the arm. This work is a game-changer,” noted FASEB Journal editor Gerald Weissmann, MD, who published the study. “Biologists have long guessed that the key to a longer lifespan is figuring out how to extend telomeres. Helen Blau and her colleagues have just done that.”
It didn’t take long for enterprising individuals to envision a lucrative business opportunity. You can now pay a company to calculate your biological age by measuring the length of your telomeres and, in a marketing gambit that surely surprises no one, firms are hawking supplements that promise to keep those cellular sentinels long and strong.
But the aging process defies easy formulas. As Gina Kolata reports in the New York Times, new research confirms that size does indeed matter — just not in the way we’ve been told to think. A study published earlier this month in the New England Journal of Medicine argues that long telomeres carry their own health risks.
A team of scientists from Johns Hopkins University School of Medicine recruited 17 people, ranging in age from 7 to 83, with a genetic mutation that produces very long telomeres. “There are things you just can’t infer from studying cells,” lead study author Mary Armanios, MD, director of the Telomere Center at Johns Hopkins, tells Kolata.
During the two-year study, Armanios and her team found that the participants were particularly susceptible to certain cancers; four of them succumbed to the disease during the study. Harriet Brown, 73, survived, but she’s suffered through benign tumors in her neck and throat as well as thyroid cancer, two cases of melanoma, and a blood disorder known as CHIP, which has been linked to heart disease and blood cancers. “There is really not much I can do at this point,” she says.
The problem with very long telomeres is that their ceaseless pattern of cell division — the process that keeps them long but not so strong — invites mutations that can trigger the growth of tumors. “It’s not that long telomeres make cells grow,” explains Norman Sharpless, MD, a professor of cancer policy at the University of North Carolina School of Medicine. “It’s that they don’t have the brakes to make them stop growing.”
Apparently, the ideal telomere length falls somewhere between very long and very short, though exactly what that means will no doubt require more research — and perhaps a bit less hubris. Sharpless may have the right idea. “Aging biology,” he admits, “is a lot more complicated than we’d hoped.”
This Post Has 0 Comments