As if it were the final plastic of the shoelace – a visual image widely used by scientists to disseminate on this subject – telomeres are the ends of the chromosomes, which keep them stable. Over time (age), telomeres get shorter as the cell divides over and over again; until eventually the damaged cell stops dividing and dies. Therefore, the longer the telomeres, in principle, that means more life expectancy and lower risk of disease. And, like height, each person is born at a certain percentile of telomere length.
The Telomeres and Telomerase Group of the CNIO (National Cancer Research Center) has spent years researching the role of telomeres in cancer and other diseases. Tumor cells are able to use telomerase (an enzyme that lengthens telomeres that healthy cells cannot use) to become ‘immortal’. But they have also studied other pathologies such as pulmonary fibrosis, due to which the lung cells are not able to regenerate, producing a scar. And it is precisely pulmonary fibrosis one of the most severe complications of COVID-19 in seriously ill patients.
The leader of the group and, in turn, director of the CNIO, Maria A. Blasco, tells us the details of this research in a telephone interview for Muy Interesante: “We had already seen that when telomeres are short or are already dysfunctional in the cells that regenerate the lung, type II alveolar pneumocytes, this was enough to induce pulmonary fibrosis ”.
What is the relationship of short telomeres to COVID-19?
“When this new disease appeared, we saw that the virus that causes it (SARS-CoV-2) was capable of infecting precisely these cells of the lung, type II alveolar pneumocytes. In addition, it was the oldest patients, who are also those with the shortest telomeres, who presented the most serious symptoms in the lung ”.
The team’s hypothesis was that patients who have the shortest telomeres, regardless of age group, are those who develop the most severe disease.
“When the virus infects the lung, SARS-CoV-2 destroys many of these type II alveolar cells; the rest, therefore, have to multiply much faster to regenerate the organ. This process of excess multiplication would contribute to the exhaustion of telomeres sooner in those people who already have short telomeres ”, explains Blasco.
The researchers observed a statistical correlation between severity of COVID-19 symptoms and telomere length through the measurement, in samples of patients admitted to IFEMA, of the length of their telomeres in blood cells.
In their work, published in the journal Aging , the scientists note the following: “We were struck by the fact that a common consequence of SARS-CoV-2 infection appears to be the induction of a fibrosis-like phenotype in the lungs and lungs. kidneys, which suggests that the viral infection could be depleting the regenerative potential of the tissues ”.
Therefore, the authors’ proposal is that it is the short telomeres that hinder tissue regeneration after infection: ” We think they develop pulmonary fibrosis because they have shorter telomeres and this limits the regenerative capacity of their lungs, ” Blasco responds.
Age, short telomeres, and severe COVID-19
Therefore, people who are in the shortest telomere percentile would have a higher risk of severe lung disease from COVID-19, regardless of age; But older people already have shorter telomeres. This would help to explain, in part, why more serious complications tend to occur more frequently in older people. As the CNIO clarifies in a press release: “As in the general population, in the patients studied the mean telomere length decreases as age increases. Furthermore, as the most seriously ill patients are also the oldest, there is also a correlation between greater severity and shorter telomere length ”.
Gene therapy to improve the long-term effects of COVID-19
Confirmation that short telomeres hinder recovery in severely COVID-19 patients would open the door to new treatment strategies, such as a therapy based on telomerase activation . As explained at the beginning of this article, telomerase is an enzyme that is capable of lengthening telomeres, and that tumor cells use to become immortal; but this enzyme is ‘off’ for healthy cells.
However, the same research group has already shown in previous works that telomerase activation has a therapeutic effect in diseases related to short telomeres, such as pulmonary fibrosis. “This therapy could improve some of the pathologies that remain in COVID-19 patients once the viral infection is overcome,” the note concludes.
How to maintain long telomeres?
Although we are talking about percentiles, which does not depend on the person born with a certain telomere length, –and since it is not yet possible to artificially lengthen them with telomerase– it is under our control to prevent telomeres from shortening faster than normal. The remedy is well known: healthy diet, frequent physical exercise, reducing stress, avoiding substances such as alcohol … All this, a priori , will help to maintain the length of our telomeres for longer and, therefore, live longer weather.
