Who Wants to Live Forever?

Dmitri Ukraintsev | Biochemistry Major

The DNA in our cells is constantly undergoing replication with each cell division throughout our lives, with some organ systems replacing themselves cell by cell in just a matter of days. DNA utilizes a number of steps to copy our genetic code into new cells so we can get taller, heal wounds, grow hair and nails, and even make germ-line cells like sperm and eggs to reproduce. However, DNA has limitations.

During replication, the “ends” of the linear chromosome, known as telomeres, are not replicated as easily as the middle of the chromosome, and so a bit of the ends are lost with each cycle. This is due to the requirement of a primer observed in the DNA replication process.

Telomerase

Diagram of the DNA transcription process showing the “end problem” and need for telomeres.

Telomeres have a short nucleotide sequence that is repeated thousands of times. These ends are protected by binding proteins and thus are akin to the tips of shoelaces; they prevent DNA strands from becoming “frayed” over time so that the chromosomes do not lose irreplaceable genetic code or activate DNA repair. Chromosomes can only undergo so many replications before their “ends” become too short. The lengths of these telomeres will slowly decrease as we age, and measuring the lengths of these telomeres has become a proposed method of quantifying the effects of aging within cells, or senescence.

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Telomeres serve a similar function to DNA as aglets to do for a shoelace. 

So are there ways to increase the lengths of our telomeres? Modern research tells us that remaining physically fit is a good way to maintain long telomeres. A recent study that evaluated cardio-respiratory fitness found that being physically fit can cause a drastic increase in the length of your telomeres. Although the exact physiological mechanisms for this are still unknown, a trip to the gym has a good chance of making your telomeres stay longer, for longer. Sleeping has also been shown to have a positive effect on your telomere lengths. A study that compared 7 hours/night sleepers found a 6% increase in telomere length for those that slept longer. Another study found that sticking to a Mediterranean style diet of veggies, fruit, legume, olive oil and less red meat could significantly increase one’s telomere length. This may lead to an explanation of the phenomenon that individuals who sustain on mostly olive-based fats tend to live longer and be healthier at an older age.

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Telomeres: The secret to eternal youth? Or just wishful thinking? 

Although all of these things may lengthen your telomeres, you shouldn’t believe cooking with olive oil and eating your veggies will make you live forever. Many studies have actually done research denying the correlation between telomere lengths and mortality factors such as cardiovascular disease, cancer events, and other age-related diseases. For example, one group found that there is no link between cancer or cardiovascular disease and telomere lengths within a large sample of elderly men. In fact, many papers have denied the correlations between telomere lengths and mortalities by any factor, although there is still much research to be done in this area.
It’s also worth noting that cancerous tumor cells are known to have an overactive telomerase enzyme, which will lengthen the telomeres to prevent the cancer cell from naturally dying from telomere loss. Thus, many of the techniques being developed or investigated to increase telomere length may contribute to cancer incidence.
Telomeres are a relatively recent discovery, and our understanding of telomeres and telomerase is not complete. There is much to learn about quantifying the effects of aging on human cells, and the effects of telomere length on human cells, but hopefully, this research might one day lead humanity to new heights, like anti-aging treatments or even new, more effective treatments for cancer and other chromosomal diseases.

References:

  1. CRF and LTL: http://www.ncbi.nlm.nih.gov/pubmed/26153476
  2. LTL not associated with mortality: http://www.ncbi.nlm.nih.gov/pubmed/24793325
  3. Sleep and LTL: http://www.ncbi.nlm.nih.gov/pubmed/23144701
  4. Mediterranean Diet and LTL: http://www.bmj.com/content/349/bmj.g6674

Images:

  1. Figure 1: http://telomeres-aging.com/
  2. Figure 2: http://telomereinformation.com/nobelprize112.php?user=admin
  3. Figure 3http://www.vegsource.com/the-healthy-librarian/a-new-role-for-omega-3-lengthening-our-telomeres–a-key-marker-for-aging-longer-life-and-health-from.html
  4. Figure 4: http://www.longevityreporter.org/blog/2015/11/13/repairing-the-clock-another-new-enzyme-found-to-lengthen-telomeres
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