Application of injectable hydrogels for cardiac stem cell therapy and tissue engineering

Cardiovascular diseases are responsible for approximately one-third of deaths around the world. Among cardiovascular diseases, the largest single cause of death is ischemic heart disease. Ischemic heart disease typically manifests as progressive constriction of the coronary arteries, which obstructs blood flow to the heart and can ultimately lead to myocardial infarction. This adversely affects the structure and function of the heart. Conventional treatments lack the ability to treat the myocardium lost during an acute myocardial infarction. Stem cell therapy offers an excellent solution for myocardial regeneration. Stem cell sources such as adult stem cells, embryonic and induced pluripotent stem cells have been the focal point of research in cardiac tissue engineering. However, cell survival and engraftment post-transplantation are major limitations that must be addressed prior to widespread use of this technology. Recently, biomaterials have been introduced as 3D vehicles to facilitate stem cell transplantation into infarct sites. This has shown significant promise with improved cell survival after transplantation. In this review, we discuss the various injectable hydrogels that have been tried in cardiac tissue engineering. Exploring and optimizing these cell-material interactions will guide cardiac tissue engineering towards developing stem cell based functional 3D constructs for cardiac regeneration.