Overview of current stem cell-based approaches to treat heart disease

Since heart failure after heart attacks results from death of heart muscle cells, researchers have been developing strategies to remuscularize the damaged heart wall in efforts to improve its function. Researchers are transplanting different types of stem cell and progenitor cells (see above) into patients to repair the damaged heart muscle. These strategies have mainly used either adult stem cells (found in bone marrow, fat, or the heart itself) or pluripotent (ES or iPS) cells.

Preliminary results from experiments with adult stem cells showed that they appeared to improve cardiac function even though they died shortly after transplantation. This led to the idea that these cells can release signals that can improve function without replacing the lost muscle. Clinical trials began in the early 2000s transplanting adult stem cells from the bone marrow and then from the heart. These trials demonstrated that transplanting cells into damaged hearts is feasible and generally safe for patients. However, larger trials that were randomized, blinded, and placebo-controlled, showed fewer indications of improved function. The consensus now is that adult stem cells have modest, if any, benefit to cardiac function.

Research shows that pluripotent stem cell-derived cardiomyocytes can form beating human heart muscle cells that both release the necessary signals and replace muscle lost to heart attack. Transplantation of pluripotent stem cell-derived cardiac cells have demonstrated substantial benefits to cardiac function in animal models of heart disease, from mice to monkeys. Recently, pluripotent stem cell-derived interventions were used in clinical trials for the first time. Patches of human heart muscle cells derived from the stem cells were transplanted onto the surface of failing hearts. Early results suggest that this approach is feasible and safe, but it is too early to know whether there are functional benefits.Research is ongoing to test cellular therapies to treat heart attacks by combining different types of stem cells, repeating transplantations, or improving stem cell patches. Clinical trials using these improved methods are currently targeted to begin around 2020.Unfortunately, many unscrupulous clinics are making unsubstantiated claims about the efficacy of stem cell therapies for heart failure, creating confusion about the current state of cellular approaches for heart failure. To learn more about warning signs of these unproven interventions, please visit Nine Things to Know About Stem Cell Treatments.

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Heart Disease A Closer Look at Stem Cells