The application of stem cell therapy to treat pathology is an ongoing subject of investigation in the medical community. While some studies have shown success, results have thus far chiefly offered progress rather than therapeutic alternatives.
The potential application of stem cells to treat damage to the heart is particularly important because once myocytes (heart muscle cells) die, they are replaced by fibrous cells (scar tissue) which provide structural support in lieu of pump function. Indeed, scar formation can also compromise heart function in other significant ways, including hindrance of the natural electrical conduction in the heart (leading to arrhythmia formation) as well as an increased predisposition to mural thrombosis (blood clots over the scar).
In a recent article published in the Lancet, the authors demonstrated remarkable findings using specific stems cells called cardiosphere-derived cells (or CDCs). In discussing their results, the authors state, "Although nature provides numerous examples of spontaneous regeneration after injury, we have, as physicians, thus far failed in our efforts to achieve therapeutic regeneration. Our study provides an initial indication that therapeutic regeneration might indeed be possible in cardiac tissue."
In their report, the authors describe how infusion of these CDCs into coronary vessels (vessels which provide blood flow to the heart muscle) after a myocardial infarction (heart attack) can decrease the size of scar tissue formation as well as increase the amount of viable heart muscle during the healing process. Though the study population was small and the effects on ejection fraction (a measure of heart function) were only modest (not statistically significant), these results present a proof of concept and will allow for further investigation into this potential new therapeutic avenue of regenerating hearts after injury (ie. heart attacks).
Here are some numbers to underscore the importance of improving heart attack therapy: According to the Center for Disease Control every year about 785,000 people have a first heart attack, and another roughly 470,000 people who have already had one or more heart attacks will have another. Furthermore, in 2008, over 616,000 people died of heart disease.