Cracking the Aging Code by Josh Mitteldorf & Dorion Sagan

Author:Josh Mitteldorf & Dorion Sagan
Language: eng
Format: epub
ISBN: 9781250061720
Publisher: Flatiron Books

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Richard Cawthon and the Role of Telomeres in Aging

“It can’t be so simple” was the conventional wisdom. If our bodies were simply getting old and dying for lack of telomerase, our bodies would produce more telomerase and solve the problem. It was known that telomeres get shorter over the human lifetime but that most cells have enough telomere length to last us through. That was all we needed. Our bodies are smart enough to make telomeres just long enough to keep our cells healthy through a normal lifetime, but not longer. Keeping the telomeres trim was thought to be the body’s way to thwart the runaway replication of cancer cells.

It was obvious that our bodies could not be dying from telomeres that are too short, so obvious that no one thought to test the idea. Besides, testing human populations for mortality takes a decade or more, and costs a fortune.

Richard Cawthon was a biochemist at the University of Utah in Salt Lake. He wasn’t convinced that there is no cost to short telomeres, and he had an idea how the question could be answered quickly and without the expense of a long-running epidemiology study. First, the biochemistry: he figured out how to measure telomere length of a sample of just a few cells. He did this by replicating the DNA many times over, cutting the DNA into fragments, and then adding a reagent that sought out the pattern TTAGGG and stuck fast to it.

A second innovation was that, instead of testing people’s telomere length and then waiting for some of them to die, he thought of a way to use historic human data. In Utah, many people stay put for a long time. There were records from people who had donated blood twenty years earlier, preserved in hospital refrigerators. Many of those same people had stayed in the area, living and dying in Salt Lake City.

In the study that Cawthon published in 2003, he measured telomere length from blood cells of just 143 people, all of whom had been sixty years old when the blood was drawn. He looked to see if a relationship existed between the lengths of their telomeres and the subsequent fate of each individual. He found a powerful relationship between life expectancy and telomere length. People with shorter telomeres had far higher death rates from infectious disease and from heart attacks. They did not have lower cancer rates than people with longer telomeres.

If the prevailing theory about cancer were correct, then there should be no net relationship between telomere length and life span. What he found instead was that people with the shortest telomeres were dying twice as fast as people with the longest telomeres.

In the years since, this relationship has been confirmed in several other studies of humans and also in several kinds of mammals and one bird species. A very large Danish study in 2015 was able to separate short telomeres from all the standard risk factors like weight and smoking and

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