The team at the Cedars-Sinai Heart Institute, whose 2012 clinical trial showed that stem cell therapy reduces scarring and regenerates healthy tissue after a heart attack, now know that stem cells boost the production of your existing heart cells (cardiomyocytes) and spur the recruitment of existing stem cells that mature into heart cells. These findings are based on a laboratory animal study, which is published in EMBO Molecular Medicine online.
According to Eduardo Marbán, MD, PhD, director of the Heart Institute, the article’s senior author and inventor of the experimental stem cell procedures and technology tested in humans, ‘We’re finding that the effect of stem cell therapy is indirect. It stimulates proliferation of dormant surviving host heart tissue, and it attracts stem cells already in the heart. The resultant new heart muscle is functional and durable, but the transplanted stem cells themselves do not last long.’
The scientists found that your heart’s native stem cells are not responsible for the normal replenishment of lost heart cells, but they do play a role in rebuilding heart tissue after a heart attack, which is consistent with previous studies. Marbán’s team showed that dying heart cells are replaced by new ones through a gradual cycling process, which escalates in response to heart attack. This enables existing heart cells to aid the development of new ones – an effect which can be amplified through stem cell therapy.
Essentially, the injection of stem cells boosts your hearts usual means of cell replacement and injury response, by turning on the genes that bolster cell production from both existing heart cells and existing stem cells. The investigational therapy can also improve your heart’s structure and function. In the last few years, Marbán and his clinical and research teams have managed to use a heart attack patient’s own heart tissue to grow specialised stem cells that were injected back into the heart, as well as significantly reducing the size of heart attack-caused scars in patients who underwent the experimental stem cell procedure, compared to others who did not.
However, Marbán, the Mark S. Siegel Family Professor, allowed that though the preliminary results are positive, his team does not know precisely how the research treatment works. Yet, he said, ‘Understanding the cellular sources and mechanisms of heart regeneration is the first step toward refining our strategies to more effectively regenerate healthy tissue after heart attacks.’