Telomeres and COVID-19

Telomeres In 2021: Could Cellular Age Be Linked to Rates of COVID-19?

Tanvir Minhas - 01 Feb 2021

In the past year, a new strain of coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, or COVID-19) has emerged and caused a world-wide pandemic. It has truly changed the way in which we live, impacting everything from governments and their citizens to scientific exploration and innovation. In light of this new virus, the scientific community has been diligently researching to try to learn more about it and potential treatments. One such new finding has been the relation between telomeres and COVID-19.

Telomeres are segments of repeating nucleotide bases that are found capping the ends of our DNA. Their main purpose is to protect our chromosomes during the replication cycle. Each time DNA is replicated, the process is known to create an overhang on one of the two DNA strands. Such an overhang is greatly unfavourable because it causes significant shortening of the DNA, putting our biological blueprints at risk. In order to combat this, the repeating bases that make up telomeres are shortened instead, since they are not protein coding and therefore can afford to be lost. Simply put, telomeres form a safeguarding loop at the end of the chromosome by attaching to the DNA overhang created during replication.

Considering DNA is replicated each time any cell in our body divides, telomeres take a lot of damage over the years! In the past, researchers have discovered that the shortening of telomeres with each replication directly correlates to cellular aging. As the telomeres shorten with each divide, a certain length is reached at which the cell is no longer able to divide without damaging the chromosome. Once a cell’s telomeres reach this certain length, it undergoes programmed cell death, or apoptosis, that is directly related to tissue death. Sources have stated that regardless of one’s chronological age, telomeres directly reflect one’s biological age because of this.

A study by Dr. Abraham Aviv of Rutgers New Jersey Medical School has linked lymphopenia, a condition relating to a decreased number of lymphocytes, to shortened telomere length. In patients with lymphopenia, their white blood cell telomeres were shorter than usual, meaning the cells that play a key role in immune response were unable to divide efficiently. Another study has confirmed that decreased amounts of immune cells found within the body of critical care patients could be related to poor prognosis. This impacts an individual’s ability to combat coronavirus if infected, leading to a larger mortality rate in such patients regardless of chronological age. Thus, patients with lymphopenia caused by shortened telomeres could be considered to be at higher risk if infected by coronavirus.

Information on how telomeres operate within our cells has led to a new path in understanding how coronavirus can impact individuals. While there is definitely more research to come on the virus that has caused a great frenzy within the scientific community, it is interesting to note how our past knowledge on basic biological concepts can equip us to tackle this newfound condition.