**9. Conclusions**

Thus, telomerase activity and telomere length are not only markers of cellular aging of CMs, but they also make a significant contribution to the development of age-related diseases. Further study of the influence of various factors on the telomerase complex and telomeric regions of chromosomes can contribute to a better understanding of the processes of telomere length changes that occur in cardiac tissue throughout life.

Studies of the regenerative capacity of the hearts of mammals and other vertebrates can also help in the formation of new approaches in the field of regenerative medicine for the treatment of such serious diseases as, for example, myocardial infarction and heart failure.

**Author Contributions:** All authors have equal contribution. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflicts of interest.
