The regeneration of the heart is hindered by short telomeres

Doctors want to teach the heart to recover independently after a heart attack

Anna Govorova, Infox.ru

Cardiologists from the Spanish National Center for Cardiovascular Diseases conducted a study and found out what prevents cardiomyocytes - heart muscle cells – from recovering after a heart attack, reports Infox.

The whole point, according to the authors of the work, is in the telomeres of cardiomyocytes – they shorten too quickly immediately after birth – i.e. they age. Telomeres are repeats of short sequences of nucleotides at the ends of chromosomes, which modern biology considers as a marker of aging. With each cell division, they shorten due to the inability of the DNA polymerase enzyme to synthesize a copy of DNA from the very end. There remains an unlinked end that does not fall into the daughter cell.

The authors believe that their research may lead to the creation of new drugs and methods for the treatment of myocardial infarction, which will help the heart muscle cells to recover on their own.

As doctors explain, in newborn children, heart muscle cells have the ability to recover. But in adults it is lost.

Why this happens, they decided to find out in an experiment with mice.

To do this, they studied how the telomere length of their cardiomyocytes changes over time. As it turned out, telomeres in mice quickly begin to shorten in the first week after birth. Interestingly, this process coincides with a decrease in the activity of telomerase, a special enzyme that telomeres can build up, and with a deterioration in the work of the p21 inhibitor protein, which plays a role in the cellular response to DNA damage.

But in mice, on the first day after birth, there was no decrease in telomerase activity, and telomeres did not shrink.

Then the scientists conducted the following experiment: they modified one-day mice in such a way that their telomerase did not work well. And in the other group, as expected, this enzyme worked well.

When they caused a heart attack in animals, cardiomyocytes did not divide in the first group, and scar tissue remained at the site of damage, while in the second group, on the contrary, they were capable of regenerating the damaged area of the heart.

On the left is the heart muscle of mice, which was able to recover after a heart attack. On the right is a heart muscle that has not recovered (scar tissue is shown in blue).

As the head of the study, Dr. Ignacio Flores, says (in a press release from Rockefeller University Press Mouse study links heart regeneration to telomere length - VM), it turns out that maintaining the telomere length of cardiomyocytes with telomerase allows them to regenerate and restore the heart muscle after damage.

"Now we are working on creating animals in which telomerase is very active. And we want to see if this will help the heart muscle recover after a heart attack," says Flores.

In the meantime, scientists report the results of their research in the latest issue of the journal of Cell Biology (Aix et al., Postnatal telomere dysfunction induces cardiomyocyte cell-cycle arrest through p21 activation – VM).

Portal "Eternal youth" http://vechnayamolodost.ru  31.05.2016