In the United States and other developed nations, heart disease kills more people every year than cancer and costs nearly twice as much to treat.¹ For these patients, adult stem cell biology signifies a new medical frontier.

Coronary heart disease (CHD) is the leading cause of death in the United States for both men and women.² CHD is caused by a buildup of plaque in the coronary arteries leading to the heart. This buildup causes the arteries to narrow and, as a result, myocardial ischemia—a restriction in blood supply to the heart—can occur. The interruption of blood supply to a part of the heart can result in myocardial infarction (MI) or acute myocardial infarction (AMI), commonly known as a heart attack.³

Significant advances have been made globally in the prevention and early treatment of myocardial ischemia and infarction, reducing morbidity, mortality and cost. Despite these advances, 160,000 patients in the United States experience AMIs that place them at risk for cardiomyocyte dysfunction leading to heart failure and other adverse cardiac-related events, including death.⁴

There is an urgent need for novel therapeutic options for the prevention and early treatment of myocardial ischemia and infarction. Adult stem cell therapy has the potential to limit or prevent the adverse consequences of a large AMI. If confirmed to be safe and effective, cell therapy may revolutionize the approach to cardiovascular disease.

In some clinical studies, patients who received coronary artery injections of adult stem cells derived from their own bone marrow after a myocardial infarction showed improvements in left ventricular function not seen in patients given a placebo. The larger the initial infarct size, the greater the effect of the infusion. There seems to be a safety advantage of autologous cells over allogeneic cells; it also appears that autologous transplanted cells remain in the heart and potentially continue to work years later, as demonstrated in preclinical animal experiments.

Clinical trials using adult stem cell infusion as a treatment approach to AMI are ongoing. Successes in pilot studies warrant large-scale longitudinal studies to examine the potential effects of progenitor-cell administration on morbidity and mortality.

One example of an adult stem cell-based therapeutic application in the treatment of AMI is AMR–001. AMR-001, manufactured by Amorcyte, Inc., is an autologous, bone marrow-derived cell therapy designed to treat AMI patients with their own stem cells.

In a Phase 1 trial, AMR–001 showed a dose–related significant improvement in perfusion. The study results demonstrated that patients receiving 10 million and 15 million cells showed significant improvement in resting perfusion rates at six months as compared to patients receiving 5 million cells and control. The data also showed that patients receiving 10 million or more cells showed a trend towards improvement in ejection fraction, the percentage of blood pumped out of a ventricle with each heartbeat, end systolic volume, infarct size and tissue death due to loss of adequate blood supply at six month follow–up. No study–related significant adverse events were reported. Having completed the Phase 1 trial with promising results, AMR-001 entered its Phase 2 clinical trial in early 2012.

Intracoronary infusions of progenitor cells have shown preliminary successes in preventing post-MI heart failure in clinical trials.⁵ Larger trials will be needed to determine if past successes translate into reductions in clinical end points. If later-phase studies are successful, it would open up a whole new way of treating heart disease. Investigation into the use of adult stem cells in the treatment of AMI may provide a promising future for regenerative therapeutics in the treatment of progressive cardiomyocyte dysfunction and in addressing one of the leading causes of death globally.

About the Author
Dr. Pecora is the chief medical officer at NeoStem, Inc., a biopharmaceutical company engaged in regenerative science and the therapeutic development of cell-based therapies. He is the former chairman and chief executive officer of Progenitor Cell Therapy.

References
1. American Diabetes Association. Economic costs of diabetes in the U.S. in 2002. Diabetes Care. 26:917–932, 2003.

 2. Feero WG, et al. Genomics of Cardiovascular Disease. N Engl J Med. 2011; 365:2098-2109.

 3. National Heart, Lung, and Blood Institute. NHLBI What Is Coronary Heart Disease? National Institute of Health, 2011. Available at http://www.nhlbi.nih.gov/health/health-topics/topics/cad/. Accessed January 27, 2012.

 4. Amorcyte: About Amorcyte. http://www.amorcyte.com/about.htm. Accessed January 27, 2012.

 5. Tongers J, et al. Stem and progenitor cell-based therapy in ischaemic heart disease: promise, uncertainties, and challenges. Eur Heart J. 2011; 32(10):1197.