Engineered human cardiac tissue.

The human heart is the first organ to develop during embryogenesis and is arguably the most essential organ for life. However, after birth, the heart has very little capacity to repair malformations such as congenital heart defects or to regenerate after an injury such as myocardial infarction. Cardiac tissue engineering addresses the need for a therapeutic biologic implant to restore cardiac structure and muscle mass. This review highlights current research in cardiac tissue engineering that uses human cardiomyocytes derived from embryonic stem cells. Other human cell sources are discussed because future human therapies will benefit from novel techniques using human-induced pluripotent stem cells and cardiomyocytes derived from direct reprogramming of somatic cells. Furthermore, this review examines the main approaches to creating engineered cardiac tissue with synthetic scaffolds, natural scaffolds, or no exogenous scaffold (i.e., "scaffold free"). The choice of scaffold and cells ultimately depends on the goals of the therapy, so the review considers how congenital heart defects define the design parameters for cardiac tissue engineering needed for surgical repair in pediatric cardiac patients.