Would you like to know when you will die?
This is a fundamentally personal and moral question which many may prefer to keep unanswered. That said, while scientific understanding of aging is making great strides it cannot yet provide an answer to the question. Though it may only be a matter of time.
Giles Tremlett over at the Guardian gives us a personal account of the fascinating science of telomeres, the end-caps on our chromosomes, and why they potentially hold a key to that most fateful question.
As a taxi takes me across Madrid to the laboratories of Spain’s National Cancer Research Centre, I am fretting about the future. I am one of the first people in the world to provide a blood sample for a new test, which has been variously described as a predictor of how long I will live, a waste of time or a handy indicator of how well (or badly) my body is ageing. Today I get the results.
Some newspapers, to the dismay of the scientists involved, have gleefully announced that the test – which measures the telomeres (the protective caps on the ends of my chromosomes) – can predict when I will die. Am I about to find out that, at least statistically, my days are numbered? And, if so, might new telomere research suggesting we can turn back the hands of the body’s clock and make ourselves “biologically younger” come to my rescue?
The test is based on the idea that biological ageing grinds at your telomeres. And, although time ticks by uniformly, our bodies age at different rates. Genes, environment and our own personal habits all play a part in that process. A peek at your telomeres is an indicator of how you are doing. Essentially, they tell you whether you have become biologically younger or older than other people born at around the same time.
The key measure, explains María Blasco, a 45-year-old molecular biologist, head of Spain’s cancer research centre and one of the world’s leading telomere researchers, is the number of short telomeres. Blasco, who is also one of the co-founders of the Life Length company which is offering the tests, says that short telomeres do not just provide evidence of ageing. They also cause it. Often compared to the plastic caps on a shoelace, there is a critical level at which the fraying becomes irreversible and triggers cell death. “Short telomeres are causal of disease because when they are below a [certain] length they are damaging for the cells. The stem cells of our tissues do not regenerate and then we have ageing of the tissues,” she explains. That, in a cellular nutshell, is how ageing works. Eventually, so many of our telomeres are short that some key part of our body may stop working.
The research is still in its early days but extreme stress, for example, has been linked to telomere shortening. I think back to a recent working day that took in three countries, three news stories, two international flights, a public lecture and very little sleep. Reasonable behaviour, perhaps, for someone in their 30s – but I am closer to my 50s. Do days like that shorten my expected, or real, life-span?