In this blog post, we take a closer look at the Hayflick limit, which is the limit of cell division, telomeres, and telomerase, and how they affect human aging and lifespan.
When we are born, we are given 25 years of life before we start to age. This time can be bought and sold, so the rich can live for hundreds of years in good health, while the poor die before they have a chance to live their lives to the fullest. This is the setting for the movie “In Time.” But what if a person’s lifespan timer was really determined by a certain cost? We would try to save money to live longer and stay young, and we would try to earn as much as possible. And if this cost could be provided indefinitely, we would probably be able to live the immortal life that Emperor Qin Shi Huang so desired, just like the rich people in the movie.
Humans actually have this timer for their lifespan. As we age, the cells in our bodies undergo cell division. At this time, cells must pay a certain cost from their own resources in order to divide. If a cell is wealthy and has a high payment capacity, it can divide endlessly, but if it is poor, it will soon be unable to divide. When cells lose their ability to pay and stop dividing, we experience aging and death. This loss of the cells’ ability to pay is called the Hayflick limit. Normal cells have enough energy to divide about 50 times, and when they use up all of this energy, they reach the Hayflick limit.
What is the cost of this division? The answer is telomeres. Telomere is a compound word derived from the Greek words telos (end) and meros (part), and refers to the end of a chromosome. At first glance, telomeres appear to be randomly arranged base sequences located at the ends of chromosomes that do not contain genetic information. However, telomeres play an important role in the process of stopping the human life timer. During the replication process, some DNA is inevitably lost from chromosomes. At this point, the telomeres at the ends of the chromosomes protect the genetic information of the chromosomes and sacrifice themselves as a cost, causing them to disappear. Therefore, telomeres lose a part of themselves with each cell division, becoming shorter with each division. When telomeres become shorter than a certain length, cells stop dividing because they cannot afford to pay the cost of cell division. Cells with stopped timers remain in the body, unable to function properly, consuming a lot of energy and causing problems such as immune system attacks.
If the length of telomeres, which is the cost of cell division, is long, we can slow down aging and live longer. The length of telomeres is largely determined by genetic and environmental factors. We inherit telomeres from our parents, and chromosomes with long telomeres, commonly referred to as “longevity genes,” enable people to live longer. However, genetics alone does not determine the cost of cell division. We can accelerate the aging process by “overconsumption” such as heavy drinking and stress, which causes telomeres to disappear quickly, or we can preserve telomeres through “conservation” such as endurance exercise and a healthy diet.
In addition, our bodies contain an enzyme that continuously produces telomeres. This enzyme is called telomerase. Telomerase attaches telomeres back to the ends of DNA, allowing cells to replicate indefinitely and ensuring that our bodies continue to receive the right parts, preventing aging. However, there is a major problem with this. Telomerase, which lengthens telomeres, also allows harmful genetic material, such as cancer, to survive indefinitely. In fact, cancer cells continue to produce telomeres through telomerase, constantly replicating their genetic material and spreading throughout the body, leading to death. As such, telomerase has a dual nature: it prevents the aging of normal cells and death, but at the same time, it can also lead to death through the risk factor of cancer.
Recently, research has been successful in reducing the risk of cancer cells by activating enzymes that increase telomere length in a short period of time through specially treated proteins. Health supplements containing only trace amounts of telomerase have been developed using natural substances and are currently in clinical trials, suggesting that the practical application of telomerase is not far off. In addition, research is continuing on ways to delay the aging of normal cells and inhibit the proliferation of cancer cells through the appropriate regulation of telomerase.
Currently, many of the world’s leading scientists are working to unlock the secrets of aging through telomere research. As a result, it has become possible to diagnose cancer by measuring abnormal telomerase concentrations in cancer cells, and it may be possible to develop anticancer drugs that target only those cells to inhibit telomerase in cancer. Above all, research on telomeres is preventing cell aging and making the dream of eternal life a reality. In the future, we may live to see the day when we can live longer through our own efforts, just like in the movies. This does not simply mean prolonging life, but enabling people to live longer, healthier, and more fulfilling lives.
