Why the elderly have a high mortality rate with Covid?

imhotep

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  • Mar 29, 2017
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    A University of Washington researcher, Prof James Anderson, who modeled a link between ageing, mortality & Covid 19 thinks it's related to immune cells. The immune system as you know, depends on it's ability to replicate the immune cells effectively at destroying the virus. However, these cannot be infinitely created. Prof Anderson suggests that the ability to create these cloned cells falls off significantly in old age.

    When DNA split in cell division, the end cap "a telomere" gets a little shorter with each division," explains Prof Anderson, who is a modeler of biological systems in the School of Aquatic and Fishery Sciences. "After a series of replications of a cell, it gets too short and stops further division. Not all cells or all animals have this limit, but immune cells in humans have this cell life."
    The average person's immune system coasts along pretty good despite this limit until about 50 years old. That's when enough core immune cells, called T cells, have shortened telomeres and cannot quickly clone themselves through cellular division in big enough numbers to attack and clear the COVID-19 virus, which has the trait of sharply reducing immune cell numbers, Anderson said. Importantly, he added, telomere lengths are inherited from your parents. Consequently, there are some differences in these lengths between people at every age as well as how old a person becomes before these lengths are mostly used up.

    Anderson said the key difference between this understanding of aging, which has a threshold for when your immune system has run out of collective telomere length, and the idea that we all age consistently over time is the "most exciting" discovery of his research.


    PS: Telomeres are the caps at the end of each strand of DNA that protect our chromosomes, like the plastic tips at the end of shoelaces. Without the coating, shoelaces become frayed until they can no longer do their job, just as without telomeres, DNA strands become damaged and our cells can’t do their job.
     
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