The problem is obvious, the solution is not: numbers do matter in cardiac cell therapy!: EXPERT'S PERSPECTIVE

This editorial refers to an article by Z. Pasha et al. [7][1] published in Cardiovascular Research in 2008. It is accompanied by a retrospective editorial by two of the authors of that original article, Z. Pasha and M. Ashraf (doi:10.1093/cvr/cvs209), as part of this Spotlight on Landmark Papers in Cardiovascular Research . Cardiac cell therapy was first proposed in 1992 to be a valuable treatment option for myocardial infarction and heart failure.1 Meanwhile, many cell types and many routes of application have been studied, and many clinical studies have also been performed. The original approach of cardiac cell therapy was aimed at replacing lost cells by newly seeded cardiomyocytes or precursors thereof, which ideally actively contribute to cardiac contractility.2 This approach is hampered by the lack of sufficient cardiomyocyte resources and by the inability of bone marrow cells to transdifferentiate into heart muscle cells, by environmental influence only. A second approach of cardiac cell therapy appears easier to conduct, in which progenitor cells (e.g. bone marrow cells) are used as carriers of cytokines or other anti-scar formation agents that beneficially influence cardiac structure and function after myocardial infarction. This latter approach has already been studied extensively in … [1]: #ref-7