Myokardiale Regeneration

Abstract

Background. Myocardial damage due to various causes can result in heart failure which is associated with substantial morbidity and mortality. Stem cell therapy might enable regenerative therapeutic concepts. Objective. Definite myocardial regeneration requires stem cell differentiation into cardiomyocytes. Adult stem cells exhibit multipotent characteristics, can only differentiate within their cell line and are not capable of forming cardiomyocytes. The generation of new cardiomyocytes from cardiac progenitor cells is still questionable. Pluripotent stem cells are more promising and include hESCs (human embryonic stemcells), SCNT (somatic cell nuclear transfer)-derived and -induced pluripotent stem cells (iPSCs). For all these cell types differential immunobiological aspects need to be taken into consideration;the aim of this article is to provide the current state of knowledge. Materials and methods. Various methods including transplant techniques in autologous, allo- and xenogeneic models as well as genetic knock-out have been used to characterize the immunobiological profile of pluripotent stem cells. Additionally, aspects from current literature are presented. Results. hESCs undergo HLA (human leukocyte antigen)-triggered and t-cell driven rejection after allogeneic transplantation. HLA I-knockdown attenuates the t-cell response with long-term graft survival in a xenogeneic model. After SCNT, the oocyte's mitochondrial genome may trigger adaptive immune responses in case of alloantigen mismatch. Despite identical genomes, differentially expressed genes in comparison to hESCs result in antigenicity of iPSCs. Conclusions. Immunologic aspects need to be considered in therapeutic stem cell concepts. Ideally, cell lines or transplantation techniques that do not cause an immune reaction will be developed.