In the realm of medical revolution, the convergence of cardiovascular health and regenerative medicine illuminates a new pathway of hope: stem cell therapy for the heart.
The heart is a vital organ responsible for pumping blood throughout the body to sustain life. However, the regenerative capacity of the heart, like any other organ, is limited when it comes to an injury or disease. In recent years, groundbreaking research in stem cell therapy has offered a glimpse of what the future holds where damaged hearts may be revived.
Stem cells are unspecialised cells that, upon differentiation, develop into specialised cell types to carry out a particular function. Their inherent versatility therefore makes them a propitious tool for repairing damaged tissues. Stem cell therapy refers to an area of regenerative medicine that uses stem cells to repair damaged heart tissue, thereby enhancing overall heart function, by introducing healthy stem cells into a harmed portion of the heart; these cells then differentiate into specialised cells specific to the heart and its function.
Source: Harvard Medical School
Image showing one way stem cell therapy could potentially work
With their diversity, stem cells can be categorised into two types: Embryonic Stem Cells (ESCs) and Adult Stem Cells (ASCs). Although both hold the ability to differentiate, their source of origin varies. Whilst ESCs are derived from embryos and are considered pluripotent, ASCs are found in various tissues and with their more limited ability to differentiate, are considered multipotent. Specifically, stem cells used for heart therapy originate from the bone marrow (Mesenchymal Stem Cells), fat tissue (Adipose-Derived Stem Cells), and the heart itself. Despite the many possible sources for stem cells, the research to identify the best source remains a challenge for scientists.
Current mechanisms of action for stem cell therapy relating to the realm of cardiovascular disease are cell differentiation, release of growth factors, and immunomodulation. The release of growth factors and cytokines (a broad and loose category of minuscule proteins that play a vital role in cell signaling) from stem cells can stimulate the repair of damaged tissue. Immunomodulation refers to stem cells that can modulate the immune response. This is done by reducing inflammation and aiding an optimal environment for quick healing. These methods have proved to provide some success. For example, in a study published in February 2012 in The Lancet, Dr. Eduardo Marban, director of the Cedars Sinai Heart Institute, and his team reported that of 17 heart attack patients treated with injections of stem cells from their hearts, within a year, scar tissue was seen to shrink by 50%.
Although some studies have shown promising results, there are still many setbacks placing the overall effectiveness of this method of treatment for heart disease under investigation. Like any other therapy, introducing stem cells into the heart poses a risk of failure or unforeseen side effects. The body’s immune system may reject the transplanted cells. And even if these cells do not undergo immune rejection, the survival, and integration of the cells into the existing tissue is another concern. There may also be a possibility that the injected cells cannot communicate with the heart’s electrical system. As a result, this poses a risk of arrhythmias where the heart beats irregularly. In addition, long-term effects are still a concern that can only be addressed with long-term trials. With these consideration factors, stem cell therapy is not yet a standard treatment. According to Harvard Medical School, stem cell therapy is currently only available to people who participate in a research trial.
Furthermore, the use of embryonic cells has raised ethical concerns with it being a controversy historically. In the late 1990s, when the therapeutic use of stem cells first came to the public’s attention, many disagreed with using human embryonic cells for medical research. The crux of the debate lies in destroying embryos for cell extraction, a practice that clashes with different people’s beliefs of what constitutes the start of human life. As the field of stem cell research advances, finding common ground that respects both ethical concerns and scientific potential remains paramount.
In summary, as the boundaries of medical possibilities are continually being tested by researchers, stem cell therapy provides a promising pathway towards healing cardiovascular health. Despite studies providing varied outcomes with researchers continuing to take different approaches in the harvest and usage of stem cells, stem cell therapy represents a frontier where cellular biology converges with the potential to transform the landscape of medical treatment.