Do Aging People Have a Higher Risk of Severe COVID Because of Shrinking Chromosomes?

Overview

I shuddered when I remembered Logan's Run, the science fiction classic in which people above a certain age choose to end their lives when I saw a headline in the Washington Post calling COVID "A Plague of the Elderly." In 1976, the year I graduated from college, the movie was released.

I would be considered elderly as a result.

Indeed, WaPo notes that "almost 9 out of 10 deaths now are in those 65 or older," making elderly people disproportionately affected or killed by COVID. That is remarkable considering that only 16% of people in that age bracket. Even so, few media pieces explore the biology underlying the heightened risk; it's possible that our shorter chromosomes impair the immune response.

Journal of Clinical Genetics and Genomics 

An open-access journal called Journal of Clinical Genetics and Genomics publishes articles with the goal of figuring out how particular gene mutations affect phenotypes and how to use that knowledge to create novel therapeutic strategies. This publication attempts to close the gap between the lab and healthcare facilities through the articles it publishes.

Like other Articles, the WaPo one Emphasizes the Obvious

"It is neither shocking nor novel that older persons are more susceptible to infections. We develop scars from previous illnesses and chronic disorders as we age, which increases our risk of developing serious illnesses."

Yes, compared to a 75-year-old with good lungs, a person with COPD has a worse survival rate from COVID pneumonia. Additionally, the likelihood of getting COPD increases with time and irritating exposure. However, the number of years by itself might serve as a stand-in for another element.

The ends of the chromosomes, or telomeres, might be to blame. As time goes on, they get smaller, much like candles do.

The Word "E"

The E word is frequently used in media reports that relate advancing age and COVID severity. However, there are several ways to define the precise threshold of official decay.

According to the UN, the retirement age is 60. According to Merriam-Webster, the definition is 65 and includes the helpful synonyms doddering, over-the-hill, and retired.

65 was identified as the critical age in a review of the use of "elderly" in 20 clinical practice guidelines for pharmacotherapy (drug prescribing) from 2014, yet it was noted that the rationale "was seldom articulated" in the guidelines, suggesting that the cutoff is ageist. Instead, prescribing decisions and professional practice recommendations should "focus more on creating a direct link between an individual patient's features and the pharmacology of their prescribed medication. 

Reduced Size and Telomeres

The length of the telomeres, which are the ends of our 46 chromosomes, is the component of aging that might be most significant in the severity of COVID. The DNA sequence TTAGGG, a six-letter word we share with all other vertebrates, is repeated along each telomere. 

Each telomere loses 50 to 150 of its last DNA bases during cell division (mitosis), gradually eroding the chromosomes. After roughly 50 divisions, mitosis comes to an end at a specific point in the shrinking, as though adhering to a cellular clock. In addition to other alterations, cancer develops when the clock breaks and cell division is unregulated.

In that their telomeres often remain long, eggs and sperm are an exception. The chromosomal tips of the gametes are extended by the enzyme telomerase, much like adding beads to a necklace. In other cell types, telomerase is not produced, and the terminals of the chromosomes shorten in time with the cell division clock.

T-Cells, COVID, and Telomeres

The relationship between COVID and telomeres is simple: older people's cells have shorter telomeres due to the passage of time, and longer telomeres are necessary for a potent T-cell response to viral infection.

Antibody production by B cells is stimulated by T cells. Both cell types are lymphocytes, which are a type of white blood cell.

T-cell counts are typically low, but they quickly increase after the early (innate) phase of the immune response. As a result, T cells alert B cells, and antibodies flood the circulation.

A Telomere Test

How much does telomere size affect their ability to fend against severe COVID? Most likely not much, which is fortunate given that we have no influence over it.

However, direct-to-consumer "telomere health DNA tests" guarantee to "monitor your cellular age depending on your telomere length" so that you can "better" it, which necessitates expensive supplement packages to aid in the pursuit of biological youth. Telomere testing: Is it Science or Snake Oil? However, let's return to science.

In order to create a model that follows T cell numbers over time, Dr Aviv worked with James Anderson and colleagues from the University of Washington using publicly available data on COVID-19 mortality. Their work was published in The Lancet e-BioMedicine.

Manuscript Submission

Each manuscript that is submitted is processed for an initial quality control check by the editorial office before going through the external peer review procedure. Preliminary quality control typically concludes in 7 days and focuses mostly on English, journal scope, and journal formatting.

Submission Link: https://www.pulsus.com/submissions/clinical-genetics-genomics.html

Twitter: @katieha19449049