«We found that we have developed gene therapy activates the stem cells of the heart —the reserve which the body can use for recovery of the myocardium after damage,» — says Pavel Makarevich of the Institute for regenerative medicine of Moscow state University, quoted in a press-service of the University.
The heart of man and animals is a unique organ whose cells can simultaneously spontaneously generate electrical impulses and contract, not requiring a constant flow of «commands» from the brain or spinal cord. The current pulses produce the so-called «cage drivers», and cardiomyocytes, muscular cells, use them to play cuts and relaxation at the right moments in time.
Violations in the work of «cage drivers» and these contacts, as a rule, lead to the development of heart failure and other serious health problems. For this reason, as scholars have noted, the heart is transplanted today only as a whole – scientists can not yet replace the necrotic areas of the heart muscle that died after a heart attack using stem cell cultures or fragments of cardiac tissue.
Makarevich and its colleagues have solved this problem by creating a special DNA molecule that can penetrate into damaged heart muscle cells and restore their livelihoods, simultaneously stimulating the growth of new blood vessels needed to supply oxygen and nutrients.
Scientists quite a long time, according to the biologist, are trying to use retroviruses and other types of gene therapy to «fix» hearts, however, virtually all such experiments ended in failure, or a very modest success.
The reasons for this, as found Makarevich and his team, was that the authors of these forms of gene therapy «aimed» at only one of several genes associated with the regeneration of the heart muscle, and ignored the rest of the DNA, the potential need for «repair» of the heart.
Guided by these considerations, genetics from Moscow state University and the SMRC of cardiology has created his version of gene therapy, which consisted of two very different gene, VEGF165 and HGF. The first section of DNA stimulates the growth of new blood vessels, and the second causes stem cells to turn into new muscle fibers.
In addition to their main functions, these genes in an unusual way affect each other – HGF plays the role of a «brake» VEGF165, reducing the rate of growth and number of new vessels. In most cases it has a beneficial effect on the body, as the appearance of excessive number of capillaries causes inflammation and swelling are very dangerous.
Work combination of these genes, biologists tested on rats, in which they artificially caused heart attack, sewing up part of their coronary arteries. When the heart tissue start to die, the doctors brought her gene therapy and watched the changes in her life.
As shown by this experiment, both gene significantly slowed the loss of those and other cells of the myocardium, and in about two weeks almost all traces of infarction completely disappeared from their cardiac tissue. Because of this the walls of the heart are not overgrown by connective tissue, which usually occurs with the development of ischemia, and became less flexible than healthy rodents.
Makarevich and his team hope that their gene therapy will be applied for the treatment of patients with myocardial infarction after conducting all preclinical and clinical studies.
