Stem cells cured heart failure
Injection of new heart cells helps to recover after a heart attack
Evgenia Efimova, Vesti, based on Medical Xpress: Stem cells restore function in primate heart-failure study
Researchers have successfully used human stem cells to restore heart function in monkeys with heart failure. Injecting such cells directly into the heart helped the animals recover after a heart attack, scientists report.
According to them, the data obtained indicate that such a technique can be effective in patients with heart failure, which, recall, is the leading cause of death worldwide.
Most cases of heart failure are caused by the death of the heart muscle due to heart attacks. The latter "turn off" the blood supply to the heart, as a result of which some heart muscle cells die. Since the heart muscle does not recover, the damaged areas are replaced by scar tissue that does not contract. As a result, the heart weakens.
At a certain point, it can no longer pump enough blood to supply the body with the oxygen it needs to function. This is called heart failure.
Heart attack survivors often develop chronic heart failure. As a rule, they experience fatigue, weakness and shortness of breath.
Charles Murry and his colleagues from the University of Washington wondered whether the introduction of new heart muscle cells into a damaged heart could help in such situations?
Specialists injected new heart muscle cells into the hearts (more precisely, in and around the newly appeared scar tissue) of six pig-tailed macaques two weeks after heart attacks. Such macaques were chosen because their hearts (size and physiology) are similar to human ones.
Heart attacks reduced ejection fractions (FB). Let us explain that the ejection fraction is an indicator reflecting the volume of blood ejected by the left ventricle at the time of its contraction (systole) into the aortic lumen.
Each animal received about 750 million "fresh" cardiomyocytes (muscle cells of the heart). As expected, there was also a control group of macaques in the study, scientists injected them with a cell-free version of the solution, which was used to inject stem cells into the animal body
It is noted that the heart muscle cells were grown from stem cells of human embryos.
Three months later, monkeys who received an injection of new heart muscle cells had a 23% higher ejection fraction than animals who were given a placebo. FB in monkeys of the control group remained unchanged.
"If we talk about people, it will mean the difference between being unable to walk more than a few blocks or carry groceries and being able to live a normal life," says Murry.
Five animals underwent cellular treatment well, but one monkey later had abnormal heart rhythms. They were short-lived, however, potentially such "malfunctions" can be dangerous for patients, Muri notes.
"To date, these are the most disturbing side effects, and we are working hard to find a drug therapy that can cope with them," the scientist adds.
After studying the hearts of animals, experts saw that human heart cells formed new muscle tissue in the damaged area. The new muscle tissue replaced 10 to 29% of the scar tissue, combined with the surrounding healthy tissue and developed into mature heart cells.
Human cardiomyocytes derived from stem cells (green) are integrated into the scar area (blue) on the heart wall (red).
By the way, other scientists have also experimented with using bone marrow stem cells and umbilical cord stem cells to treat heart failure. Their work also improved the performance of the heart, but not as effectively as the heart muscle cells coped with it in the latest study.
Speaking about the ultimate goal, Murry notes that they intend to develop a treatment that helps people recover soon after a heart attack to prevent heart failure.
He and his colleagues plan to determine the effectiveness of such cells in humans in 2020. The results of a recent study are presented in the scientific publication Nature Biotechnology (Liu et al., Human embryonic stem cell–derived cardiomyocytes restore function in infarcted hearts of non-human primates).
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