Stem Cell Therapy for Heart Failure
Heart failure (HF) affects millions of individuals worldwide, both genders, and all races. HF affects 5 million Americans, and is a condition where the heart progressively weakness, unable to produce enough blood to meet the body’s demands. A promising treatment for severe and end-stage heart failure is stem cell therapy. Presented at the American College of Cardiology’s Annual Scientific Session, researchers have proposed that more clinical studies are used to evaluate this treatment.
Heart attacks and heart failure are both associated with loss of cardiac muscle cells, which are not regenerated over time. This can leave the patient with significant complications and disability. Researchers using stem cells have noted an ability to form cardiomyocytes, which improve overall cardiac function. Clinical trials are focused on treated heart failure secondary to previous heart attacks.
The most common type of stem cells are bone marrow progenitor stem cells. These are obtained from the patient’s own bone marrow. These cells can be injected into the heart muscle or sac surround the heart. The transplanted cells undergo differentiation into cardiomyocytes (heart muscle cells), and this is found to improve left ventricular ejection fraction. The results have led researchers to continue to seek funding for more human clinical trials so this therapy can be used more and more in clinical practice.
Human Studies involving Stem Cell Therapy
In a large study, 109 patients were randomized to receive stem cell therapy or a placebo treatment. The patient’s own bone marrow was used in the treatment group, and subjects were evaluated over a 12-month period. To date, this is the largest double-blinded study of its kind involving stem cell therapy for heart failure. Based on the preliminary findings, researchers have reported positive results for people with class III and IV heart failure. After a year, 38% of patients given stem cells had a significant improvement in the lower proportion. There was also a noted reduction in cardiovascular clinical events in the treatment group compared to the control group.
In 2005, researchers studied 30 patients with HF treated transepicardially with stem cells. Researchers found that the patients had improvement in viability and increased left ventricular output. A 2008 study with 23 people showed improvement in HF symptoms, reduced left ventricular size, and improved viability after one year. Finally, improved ejection fraction output was noted in 40 people who had transepicardial stem cell transplants in 2007.
Animal Studies involving Stem Cell Therapy
Past trials have shown improvements and stem cell success when the cell solution was injected percutaneously via the groin. With arrhythmias associated with HF, stem cells have shown to have preventive effects. In rate subjects treated with stem cells, researchers found that neighboring cardiomyocytes by gap junctions, which increased cardiac ability through electrotonic interactions. In this study, researchers found spontaneous electrical activity that improved arrhythmias.
In a rat study, researchers injected bone marrow into subjects, and evaluated ventricular function after 20 days. They found improvements at that time in cardiac function. Monitory by ECG showed that 70% of the rats who had been injected with stem cells showed better cardiac rhythms. There was less inflammatory damage in the homogenous donor cell group.
Resources
Menasche P (2009). Are arrhythmias a real safety concern? Circulation, 119, 2735-2740.
Patel AN, Henry TD, Quyyumi A, et al. (2016). Ixmyelocel-T for patients with ischaemic heart failure: a prospective randomised double-blind trial. The Lancet, 2016 DOI: 10.1016/S0140-6736(16)30137-4