Acute myocardial infarction (AMI) often leads to congestive heart failure, a condition associated with high subsequent mortality. Pharmacological treatment and, more importantly, primary angioplasty have notably decreased early mortality and thereby improved the long term prognosis of patients with AMI. However, in the largest study so far, involving more than 14 000 patients with AMI and impaired left ventricular function, 1 year mortality was still 13% despite guideline conforming pharmacological treatment and use of implantable automatic defibrillators.1 Therefore, preventing the progression of disease with further complications such as left ventricular aneurysm or severe depression of left ventricular function is still a major challenge.

Recent studies demonstrating the ability of stem cells to (trans-)differentiate into cardiac myocytes have challenged the old belief that the heart is a terminally differentiated organ. These findings initiated intense basic and clinical research with the aim of using this stem cell ability in order to repair ischaemically damaged myocardium. This article provides an overview of the current basic scientific knowledge on the role of stem cells in myocardial infarction, and the results of the first studies implementing stem cell therapy in the clinical setting.

WHICH CELL?

Embryonic stem cells

The most primitive of all stem cells are embryonic stem (ES) cells. ES cells have the broadest developmental potential since they can give rise to cells of three embryonic germ layers. Several different ES cell lines have been manipulated to produce cardiomyocytes. In a mouse model, these cells expressed cardiac specific proteins and formed grafts when injected into ischaemically damaged myocardium. Furthermore, the ES cell derived cardiomyocytes contracted in synchrony with adjacent cells, and the grafts remained stable over several weeks after implantation.2 It has also been demonstrated that human ES cells can give rise to cardiomyocytes by using an embryoid body model.3 These studies show that functionally intact cardiomyocytes …