Although the treatment of acute myocardial infarction has improved considerably and the mortality rate is reduced, patients who survive may develop loss of cardiomyocytes, scar formation, ventricular remodeling, and ultimately heart failure. The treatment of the most severe types of heart failure is heart transplantation, but this therapeutic intervention is not available for a large number of patients due to a shortage of donor hearts.
Since current pharmacological and interventional approaches are unsuccessful to regenerate infarcted myocardium, new approaches like gene- or cell-based therapies are tested to prevent loss of cardiac tissue, enhance angiogenesis, and to reduce left ventricular remodeling. Exciting and promising data on laboratory animals have moved the field rapidly into clinical trials. Although several clinical trials proved the safety and feasibility of using gene- and cell-based therapies, many challenges remain before large-scale novel treatment modules will be available.
The purpose of this review is to summarize the key findings of larger, randomized clinical trials in cardiovascular medicine using both gene and cell-based therapy, and to emphasize the most significant questions that emerged from the clinical experience so far, such as the optimal gene or cell type to be used, the ideal delivery route, and for DNA the ideal delivery system. Understanding the mechanisms of gene- and cell-based therapies is essential for designing the next phase clinical studies in the field of regenerative medicine.