Independent myocardial regeneration is questionable
Does the heart have the ability to heal itself?
Kirill Stasevich, CompulentaScience does not stop trying to awaken regenerative abilities in the heart: there is no need to explain how many medical problems this would solve.
In recent years, works of this kind have often referred to the article by Porrello et al. Transient Regenerative Potential of the Neonatal Mouse Heart, published in 2011 in Nature. Its authors claimed that they managed to achieve self-healing of the heart muscle of newborn mice after surgery.
Generally speaking, the appearance of new cells in the mammalian heart is possible only during intrauterine development, and stem cells in the heart fall asleep immediately after birth. But in 2011, it was possible to detect the restoration of cells exactly that in newborn mice. The piquancy of the results was also added by the fact that the heart was restored not at the expense of stem cells, but with the help of ordinary, mature muscle cells, which allegedly had the ability to divide. It is clear that everyone immediately started talking about the restoration of the human heart – since everything worked out for mice.
However, it is possible that the dreams of a regenerating heart will have to say goodbye. Ditte C. Andersen from the University of Southern Denmark, together with colleagues, tried to reproduce exactly the already legendary work with mice. In one-day mice, about 15% of the cardiac tissue in the area of the apex of the left ventricle had to be surgically removed, after which it remained only to observe how the heart would restore its anatomy and functions, which took 21 days.
No recovery of functions was noticed this time, but something else was discovered: the heart was overgrown not with muscle cells, but with an ordinary scar, which is formed, for example, after a heart attack. The results of the experiment are published in the journal Stem Cell Reports, so far in the form of a pdf file (Andersen et al., Do Neonatal Mouse Hearts Regenerate following Heart Apex Resection?).
Mouse heart with a piece of ventricle cut out
and beginning to form a scar (colored red)
(illustration by the authors of the work).
Of course, the authors of the 2011 article were not slow to doubt the new data, writing them off as inept execution of the experiment (however, no more specific comments were followed). In addition to them, other research groups responded, which also tried to reproduce the regeneration of the heart. According to Bernhard Haubner from the Institute of Molecular Biotechnology (Austria), his group also failed to obtain reliable results – mostly due to the fact that mice very often died after surgery. That is, it is possible that regeneration took place in them, but how and how much, it is impossible to say.
On the other hand, some scientists have successfully reproduced the regeneration of the heart. According to Richard Lee from Harvard (USA), it is not surprising that different laboratories have different results: with the surgical removal of a part of the ventricle, the state of the heart is affected by many factors that can help both regeneration and scar healing, and it is impossible to say in advance which process will prevail.
In general, as you can see, the question of heart regeneration, to put it mildly, does not have an unambiguous answer. Now most laboratories dealing with this problem force experimental animals to suffer a heart attack: after all, this is a more natural injury than cutting out a piece of the heart. As for the method described above, the analysis of the reasons why different researchers get different results can be useful not only in understanding the physiology of the heart, but also for purely methodological purposes. After all, there can be no talk of any regeneration of the heart in the clinic until the methods and results are coordinated with each other so as to exclude all possible "surprises".
However, to make the heart cells divide, we still have to get into their molecular genetic structure, even if we are not going to turn them into stem cells.
Prepared based on the materials of The Scientist: “Breakthrough” Tough to Reproduce.
Portal "Eternal youth" http://vechnayamolodost.ru07.04.2014