Epicardial cells derived from human embryonic stem cells augment cardiomyocyte-driven heart regeneration.

The epicardium and its derivatives provide trophic and structural support for the developing and adult heart. Here we tested the ability of human embryonic stem cell (hESC)-derived epicardium to augment the structure and function of engineered heart tissue in vitro and to improve efficacy of hESC-cardiomyocyte grafts in infarcted athymic rat hearts. Epicardial cells markedly enhanced the contractility, myofibril structure and calcium handling of human engineered heart tissues, while reducing passive stiffness compared with mesenchymal stromal cells. Transplanted epicardial cells formed persistent fibroblast grafts in infarcted hearts. Cotransplantation of hESC-derived epicardial cells and cardiomyocytes doubled graft cardiomyocyte proliferation rates in vivo, resulting in 2.6-fold greater cardiac graft size and simultaneously augmenting graft and host vascularization. Notably, cotransplantation improved systolic function compared with hearts receiving either cardiomyocytes alone, epicardial cells alone or vehicle. The ability of epicardial cells to enhance cardiac graft size and function makes them a promising adjuvant therapeutic for cardiac repair.: This work was supported by the British Heart Foundation (BHF; Grants NH/11/1/28922, G1000847, FS/13/29/30024 and FS/18/46/33663), Oxford-Cambridge Centre for Regenerative Medicine (RM/13/3/30159), the UK Medical Research Council (MRC) and the Cambridge Hospitals National Institute for Health Research Biomedical Research Centre funding (SS), as well as National Institutes of Health Grants P01HL094374, P01GM081619, R01HL12836 and a grant from the Fondation Leducq Transatlantic Network of Excellence (CEM). J.B. was supported by a Cambridge National Institute for Health Research Biomedical Research Centre Cardiovascular Clinical Research Fellowship and subsequently, by a BHF Studentship (Grant FS/13/65/30441). DI received a University of Cambridge Commonwealth Scholarship. LG is supported by BHF Award RM/l3/3/30159 and LPO is funded by a Wellcome Trust Fellowship (203568/Z/16/Z). NF was supported by BHF grants RG/13/14/30314. NL was supported by the Biotechnology and Biological Sciences Research Council (Institute Strategic Programmes BBS/E/B/000C0419 and BBS/E/B/000C0434). SS and MB were supported by the British Heart Foundation Centre for Cardiovascular Research Excellence. Core support was provided by the Wellcome-MRC Cambridge Stem Cell Institute (203151/Z/16/Z), The authors thank Osiris for provision of the primary mesenchymal stem cells (59

Generation of functional cardiomyocytes from rat embryonic and induced pluripotent stem cells using feeder-free expansion and differentiation in suspension culture.

The possibility to generate cardiomyocytes from pluripotent stem cells in vitro has enormous significance for basic research, disease modeling, drug development and heart repair. The concept of heart muscle reconstruction has been studied and optimized in the rat model using rat primary cardiovascular cells or xenogeneic pluripotent stem cell derived-cardiomyocytes for years. However, the lack of rat pluripotent stem cells (rPSCs) and their cardiovascular derivatives prevented the establishment of an authentic clinically relevant syngeneic or allogeneic rat heart regeneration model. In this study, we comparatively explored the potential of recently available rat embryonic stem cells (rESCs) and induced pluripotent stem cells (riPSCs) as a source for cardiomyocytes (CMs). We developed feeder cell-free culture conditions facilitating the expansion of undifferentiated rPSCs and initiated cardiac differentiation by embryoid body (EB)-formation in agarose microwell arrays, which substituted the robust but labor-intensive hanging drop (HD) method. Ascorbic acid was identified as an efficient enhancer of cardiac differentiation in both rPSC types by significantly increasing the number of beating EBs (3.6 ± 1.6-fold for rESCs and 17.6 ± 3.2-fold for riPSCs). These optimizations resulted in a differentiation efficiency of up to 20% cTnTpos rPSC-derived CMs. CMs showed spontaneous contractions, expressed cardiac markers and had typical morphological features. Electrophysiology of riPSC-CMs revealed different cardiac subtypes and physiological responses to cardio-active drugs. In conclusion, we describe rPSCs as a robust source of CMs, which is a prerequisite for detailed preclinical studies of myocardial reconstruction in a physiologically and immunologically relevant small animal model.Open-Access-Publikationsfonds 2018peerReviewe