Cardiac regeneration using human‐induced pluripotent stem cell‐derived biomaterial‐free 3D‐bioprinted cardiac patch in vivo

One of the leading causes of death worldwide is heart failure. Despite advances in the treatment and prevention of heart failure, the number of affected patients continues to increase. We have recently developed 3D‐bioprinted biomaterial‐free cardiac tissue that has the potential to improve cardiac function. This study aims to evaluate the in vivo regenerative potential of these 3D‐bioprinted cardiac patches. The cardiac patches were generated using 3D‐bioprinting technology in conjunction with cellular spheroids created from a coculture of human‐induced pluripotent stem cell‐derived cardiomyocytes, fibroblasts, and endothelial cells. Once printed and cultured, the cardiac patches were implanted into a rat myocardial infarction model (n = 6). A control group (n = 6) without the implantation of cardiac tissue patches was used for comparison. The potential for regeneration was measured 4 weeks after the surgery with histology and echocardiography. 4 weeks after surgery, the survival rates were 100% and 83% in the experimental and the control group, respectively. In the cardiac patch group, the average vessel counts within the infarcted area were higher than those within the control group. The scar area in the cardiac patch group was significantly smaller than that in the control group. (Figure S1 ) Echocardiography showed a trend of improvement of cardiac function for the experimental group, and this trend correlated with increased patch production of extracellular vesicles. 3D‐bioprinted cardiac patches have the potential to improve the regeneration of cardiac tissue and promote angiogenesis in the infarcted tissues and reduce the scar tissue formation.