The Effects of Telomerase on Aging

Over the past thousands of years, mankind has sought ways to live forever. Legends such as the fountain of youth and the philosopher’s stone have helped to spark fascination and curiosity about the possibility of eternal life. While the philosopher’s stone and fountain of youth were only ancient myths, modern biological research might have uncovered a process that might help humans live longer, healthier lives. This process involves an, until recently, little-known enzyme called telomerase. However, before telomerase can be defined, one must understand the aging process in which it’s used and why it’s so important.

Human cells are constantly dividing. Whether they’re skin cells attempting to help replenish the epidermis or bone cells participating in bone remodeling, cells constantly need to replicate. When somatic cells divide, they do so through a process known as mitosis. During this process, chromosomes create duplicates of themselves in order to make a new cell. Chromosomes are able to accurately replicate themselves many times because of protective “caps” on their ends called telomeres. According to Scientific American, “Telomeres are repetitive DNA sequences at the ends of chromosomes which act as protective caps” (Rehman, 2014). When cells divide during mitosis, the chromosomes duplicate in order to ensure that both “daughter” cells receive the same amount of DNA. The telomeres protect the chromosomes during this process to ensure the integrity of the DNA.

Telomeres do an excellent job of helping to secure our genetic material, unfortunately they don’t last forever. According to Scientific American, “During the DNA replication and the separation of the newly formed chromosomes, small chunks of DNA are trimmed off at the end of the chromosomes” (Rehman, 2014). Having telomeres on their ends for protection, the chromosomes and their DNA remain intact. However, as one starts to age and DNA is continually trimmed, the telomeres start to get shorter. This affects a person’s ability to heal and repair because, according to Scientific American, “short-telomere cells would have to give up early on because their protective telomere caps would dwindle” (Rehman, 2014).

When telomeres shorten, they can create “errors” in the DNA which result in senescence, or cellular deterioration due to aging. In a study conducted by Nobel Laureate Dr. Elizabeth Blackburn, it was discovered that, “the individuals in the shortest telomere group were three times more likely to develop cancer than the longest telomere group within the ten year observation period” (Rehman, 2014). Scientific American also stated that, “A similar correlation between long telomeres and less disease also exists for cardiovascular disease” (Rehman, 2014).

While all of these shortened telomere correlations are certainly enlightening, the question remains: what causes telomere shortening? One of the biggest causes of telomerase wear and tear seems to be environmental stressors. According to Scientific American, “Blackburn listed a few of them such as stress hormones, oxidative stress and inflammatory stress” (Rehman, 2014), all of which occur on the molecular level. Oxidative stress is when the overproduction of oxygen causes proteins to oxidize and become unstable, upon which they become either useless or detrimental. Inflammatory stress is when a cell’s inflammatory response exceeds its ability to repair and recover. Of inflammatory stress, Scientific American also stated that, “recent studies in mice have shown that activation of inflammation pathways in the brain can suppress cognitive function, muscle strength and overall longevity” (Rehman, 2014).

First discovered in the 1980s and 1990s, the enzyme telomerase seemingly acts as an anti-aging substance. Typically found in regenerative cells like stem cells, telomerase prevents the wearing-away of telomeres and allows cells to replicate much more often and without error. While it might seem simple to just add more telomerase to our chromosomes and end aging once and for all, Dr. Blackburn also implied that, “Too much telomerase can help confer immortality onto cancer cells and actually increase the likelihood of cancer, whereas too little telomerase can also increase cancer by depleting the healthy regenerative potential of the body” (Rehman, 2014).

Only by administering the exact amount of telomerase required would actually help to prevent aging, and there isn’t much margin for error. While telomerase injections might not be the key to anti-aging, there might be a way to lengthen telomeres. According to Dr. Blackburn, when speaking of a telomere observation study done on multiple sets of twins, “And they said, who’s got the longer telomeres; and it was the twin who did some exercise. The one who didn’t had shorter telomeres, and yet their genes are the same” (DiChristina & Mirsky, 2015). While that study may seem like very compelling evidence, she also stated that, “we don’t know if telomeres actually grow with exercise” (DiChristina & Mirsky, 2015).

Repeated cell division wears away telomeres over the span of time which increases cellular aging. Environmental stressors like inflammatory stress and oxidative stress can accelerate this process over time. Fortunately, telomerase can help replenish or “cap off” telomeres in order to preserve the integrity of a cell’s DNA, and allow its chromosomes to successfully and accurately replicate themselves. Research into this relatively new enzyme is still progressing and “hard” facts are still yet to be determined. However, with the studies done on the correlation between shorter telomeres and cancer and heart disease, it provides the scientific community with plenty of motivation to continue this fascinating research and to hopefully, someday find a way to extend human life.

REFERENCES

DiChristina, M., & Mirsky, S. (2015, April 9). Nobelist Talks about Exercise and Chromosome
Integrity. Retrieved April 28, 2015, from http://www.scientificamerican.com/podcast/episode/nobelist-talks-about-exercise-and-chromosome-integrity/

Rehman, J. (2014, July 5). Aging: Too Much Telomerase Can Be as Bad as Too Little |
Guest Blog, Scientific American Blog Network. Retrieved April 28, 2015, from http://blogs.scientificamerican.com/guest-blog/2014/07/05/aging-too-much-telomerase-can-be-as-bad-as-too-little/