Imagine a world where the average human lived to be 100 years old and was still as active as a 40 year old by today’s standards. The advances in modern science allow this idea to be perceived and almost become implemented in society. As with all research, it takes time as well as repeated experimentation in order to ensure it is fact. Therefore, this age-defying technology is at it’s infancy but bit by bit is making its progress through the scientific community. This paper will dive into the research behind human aging on a chromosomal level, and inform one of the newly discovered abilities that researchers have to delay ageing as well as associated diseases.
Aging happens to every individual and will continue to occur unless the chromosome itself is manipulated in order to setback aging. To understand how aging can be reversed or delayed, one first has to understand what aging actually is. When a somatic (body cell) divides, it produces an exact copy of all the DNA. However, when the DNA is copied the length of the strand of DNA is shortened at the area of telomere. The telomere is the end of a chromosome which serves as an ending and prevents destruction of DNA when proceeding through normal cell process’. Over several divisions, the chromosome length becomes shorter and shorter and eventually it starts losing vital loci which are essential for life. The vital loci are parts of the chromosome that code for certain proteins, which life depends on. Once the cell starts to shorten to the vital area of the DNA, it dies. This is represented in figure 1.0 (Wang, 2017). Over time this leads to bones becoming weaker, and skin losing it’s elasticity (Williams, 2016). These are natural process’ for the body, yet many people do not enjoy them and are driven to reverse the effects of aging. Now that the genetic reason for aging has been identified it is possible to look at how to stop it. This paper will look at two ways to delay ageing; telomere extension and stem cells.
Since the decay of replication is due to the shortening of the telomeres, one way to reduce the degeneration of an organism’s life span is to extend the telomeres. This would allow for the DNA to replicate more than the normal amount and thus extending the life of the cell. Once the life of the cell is extended, the life of the organism can be extended. At Stanford School of Medicine they have successfully extended the length of telomeres in live cultures of adult cells. This extension allowed for the new cells with the extended telomeres to reproduce up to 40 times (1600 times total) more than the untreated cells whom replicate around 40 times in a life cycle (Ramunas, 2015). This method involves suppression of the cells immune defense in order for the TERT (Telomerase reverse transcriptase) encoding message to remain present (Ramunas, 2015).
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TERT is an enzyme that has the ability to elongate the telomeres of chromosomes. It does this by adding random, unimportant sequences of DNA to the distal end (telomere) of the chromosome by using the complementary RNA strand as a template (Rmatics, n.d.) This process forces the sequences to sacrifice themselves when it comes to mitotic division. Once the additional elongated segments of DNA are placed on the telomere, their main function is to erode away, thus keeping the important (coding) region of the DNA safe from being cut during replication. This small change allows for more replications, thus longer cell life ergo longer human life.
Another strategy for the extension of the telomeres uses an enzyme called telomerase. Telomerase’s main function is to add nucleotides to the telomeres. The following experiment used T cells as their test subject. T cell or thymocyte comes from a stem cell and is specifically designated to serve as immune response cell for the body (T cell 2015). An experiment at the American Society of Hematology studied the outcomes of cell life by manipulating telomerase to over express itself. Meaning they forced telomerase to go into a hyperactive state where it adds copious amounts of nucleotides onto the telomeres of T-cells. The final outcome of this was an extended cell life cycle (Rufer, 2001).In order to physically observe the success of the telomere extension in the experiment, the telomeres must be illuminated. To do this, the group decided to transduce GFP (green fluorescent protein) to the product of the overexpressed telomerase. Once the telomeres were extended, they could be viewed under an illuminated electron microscope. This is seen in figure 2.0 (Rufer, 2001). In other words, they delayed the cells death, allowing it to continue normal growth and function. This idea is similar to the one at Stanford, however it accomplishes the same goal using a different route.
Even though telomere extension has been successful in a lab, human testing is still a good distance away. The possibility of developing cancer from this technique is a great risk of both methods. Since the goal is to have the cell life extended and thus allowing it to divide more, it is very prone to cancer. If the experimental cell loses control and the cell has a higher rate of production than it normally would, cancer could spread extremely quickly. Researchers do not want to risk this possibility. Meaning the instability of the chromosomes with extra telomere sequences is a perfect storm for a new disease if mutation occurs. Though this seems like great way to delay aging, there is also promising research in stem cells.
When an organism is originated, it begins growth by creating stem cells. There are several different types of stem cells. There are adult stem cells, embryonic stem cells, and induced pluripotent stem cells (Stem, 2016). The difference between types of stem cells is the embryonic stem cells can develop into any cell in the human body, whereas the adult stem cells can only form into some but not all specialized cells. Finally the iPSCs differentiate from any other stem cell because they are originally specialized cells, but they can be re-specialized to another type of cell (Stem, 2016). For interest of age delay, the embryonic stem cell seems to hold the most promise.
Stem cells go through mitosis several times and they later develop into specialized cells (Your, 2018). For example, a blood stem cell can produce more blood stem cells which then can specialize into red blood cells if the body needs more blood. If the stem cells are applied later in an organism’s life, such as humans, it may be able to reduce or reverse the effects of aging. Since aging is partly due to the shortening of telomeres and the destruction of chromosomal DNA, if there are fresh embryonic stem cells to replace the damaged ones it would phenotypically appear as if the individual is not aging. This theory may work because the embryonic stem cells have increased telomerase activity (Hiyama, 2007). The increase in telomerase allows for extension of the telomeres and therefore longer cell life. Currently there is testing being done with human subjects as to whether or not stem cells can reverse the effects of aging. One study shows that elderly subjects were provided one treatment of stem cells from several donors bone marrow. The donors age ranged from 20 to 45 years old and the elderly subjects experienced an increase in physical ability as well as no noted adverse effects (Haridy, 2017). This is a promising study because it will open the door for other research groups to experiment with stem cells on human subjects in regards to rejuvenation of body systems (Honoki, 2017).
Stem cells may also be used to repair damaged body systems, which will then improve the individual’s overall health and delay ageing. Over time cells become damaged from normal process’ and errors. The DNA in these aged cells are repaired naturally, however it takes time and does not always restore the cell to its former function. The lack of perpetual cell repair leaves the organ system prone to disease. Therefore, another way to delay ageing is by using stem cells to prevent age related disease. Some diseases that stem cells may be able to prevent are heart disease and parkinson’s (Ho, 2005). The idea is new embryonic stem cells can specialize themselves into the cells of the diseased organ system. In theory, if the individual was likely to develop heart disease, they could be given stem cells which would become cardiomyocytes (heart cells). The new cells would replenish the old deteriorating cells. Once the malfunctioning cells are replaced, it would be as if the entire heart never had a problem (Repairing, 2013). Using stem cells for organ replenishment could delay ageing in the fact that the individual’s lifespan could increase.
Ageing is a natural process which eventually ends in death unless it is prevented. Age delay research is an ever growing field in the realm of science and it will not stop until there are proven remedies. Techniques must first be proven to be safe in order to start trials on humans. Once the trials have concluded the evidence is supported, the techniques may be available and implemented to the public. The two most advanced and promising techniques are telomere extension as well as stem cell research. It is possible and likely probable in the near future that the average lifespan of a human can be extended and the ageing process delayed.
