If we stopped aging after the age of 25 and were given a year to buy and sell, as in the movie In Time, we would save money and try to make as much as possible to extend our lives. The division and aging of cells is determined by the length of telomeres and the enzyme telomerase, which scientists use to study aging and cancer.
When we are born and turn 25, we are given one year to stop aging. This time can be bought and sold for money, allowing the rich to live for hundreds of years in a healthy body, while the poor die before their lives are fully realized. This is the setting of the movie In Time. But what if the timer on our lifespan is really determined by the cost of living? We would try to stay young and long by saving that cost, and we would try to earn as much as we can, if we can earn it. And if we had an unlimited supply of this money, we could probably live the life of immortality that Qin Shi Huang wanted so badly, just like the rich people in the movie.
We actually have this timer for our lifespan. When we get old, it means that each organ in our body is dividing cells. In order to divide, the cells have to pay a certain cost out of their own resources. If the cell is rich and able to pay, it can divide endlessly, but if it is poor, it will not be able to divide for long. If the cell becomes insolvent and stops dividing, aging and death will come to us. This loss of cellular solvency is called the Hayflick limit. Normal cells only have enough money to divide about 50 times before they reach the Hayflick limit.
What is the cost of this division? The answer is telomeres. The word telomere is a compound of the Greek words telos (end) and meros (part), and refers to the ends of chromosomes. At first glance, telomeres look like random sequences of bases at the ends of chromosomes that don’t carry any genetic information. However, they play an important role in the process of stopping the human lifespan timer. Chromosomes inevitably lose some of their DNA during the replication process, and these telomeres at the ends of chromosomes pay for it by keeping the chromosome’s genetic information safe and paying for it with their own sacrifice. As a result, telomeres lose part of themselves with each cell division and become shorter with each cell division. The moment these shortened telomeres fall below a certain level of length, the cell stops dividing because it has nothing to pay for them to divide. These timer-stopped cells stay in the body and don’t function properly, using up a lot of energy and causing problems such as immune system attacks.
Longer telomeres, which are the cost of cell division, can slow down the aging process and allow us to live longer. The length of telomeres is largely determined by both congenital and acquired factors. We inherit the cost of telomeres from our parents as a “legacy,” and what we call longevity genes contain chromosomes with longer telomeres, which allows the person to live longer. But “inheritance” is not the only cost of cell division. We can “overspend” on telomeres through things like binge drinking and stress, which accelerate the aging process, or we can “conserve” them through things like endurance exercise and a healthy diet.
In addition, your body has an enzyme that keeps telomeres going. This enzyme is called telomerase. Telomerase is responsible for reattaching telomeres to the ends of DNA, which gives the cell the money to replicate indefinitely, and ensures that the body continues to receive the right parts, thus preventing aging. But there’s a big problem. The same telomerase that lengthens telomeres also allows harmful genetic material, such as cancer, to survive in perpetuity. In fact, cancer cells use telomerase to keep making telomeres, constantly replicating their genetic material and metastasizing throughout the body, killing you. As such, telomerase is a double-edged sword: it protects us from death by preventing normal cellular aging, but it can also kill us in the form of cancer.
Recently, researchers have been able to reduce the risk of cancer cells by activating the enzyme to lengthen telomeres for a short period of time through specially treated proteins, and dietary supplements containing very small amounts of telomerase from natural sources have been developed and are in clinical trials, so it seems that the future of practical use of telomerase is not far away. Furthermore, research continues to explore ways to delay the aging of normal cells and inhibit the proliferation of cancer cells through the proper regulation of telomerase.
Many of the world’s top scientists are currently working to unlock the secrets of aging through telomere research. As a result, it has become possible to diagnose cancer by measuring the abnormal concentration of telomerase in cancer cells, and it may be possible to create anti-cancer drugs that inhibit telomerase by targeting only that part of the cell. Most importantly, research on telomeres is helping us to prevent cellular aging, making the dream of immortality a reality. We may soon see a day when we can buy time with effort, just like in the movies. Not just a longer life, but a successful life, a long life in good health.
