Experimental Animal Models of Myocardial Damage in Regenerative Medicine Studies Involving Adult Bone Marrow Derived Stem Cells: Ethical and Methodological Implications

Cardiac performance after myocardial infarction is compromised by ventricular remodeling, which represents a major cause of late infarct-related chronic heart failure and death. In recent years, the scientists' interest has focused on the hypothesis that the administration of bone marrow progenitors, following myocardial infarction, could ameliorate left ventricular remodeling by continuing to differentiate along the haematopoietic lineage. This approach has been developed minding to the consolidated use of transfusions to restore lost or depleted blood components and, therefore, as an enriched dose of various progenitors, generally autologous, injected peripherally or directly in the infarcted area. Since the safety of this therapy was not yet established, for ethical reasons pioneering researchers involved in these studies used animal models as surrogate of the human biologic system. Herein this hypothesis of therapy resulted in an increased use of living animals and in the reappraisal of models of myocardial damage with limited discussion on the theoretical basis of animal models applied to cell-based therapies. Recently, the European Union and its commission for surveillance of laboratory animals advanced a new proposal to restrict the use of living animals. This review will focus on the history of models utilization in biomedicine, with particular attention to animal models, and delineate an operative comparison between the two best known models of myocardial injury, namely coronary ligation and cryodamage, in the perspective of adult stem cell research applied to cardiovascular regenerative medicine.