Use of Human Pediatric Cardiac Progenitor Cells in an Engineered Heart Patch
Jacot, Jeffrey G
Doctor of Philosophy
Congenital heart defects (CHD) are the most common birth defects in the US and the leading cause of death in newborns. Some of the most prevalent CHD require surgical interventions with patch materials. However, current commercial patch materials are acellular, non-conductive, and non-contractile; they can induce arrhythmias and require reoperations. We envision an engineered cardiac patch seeded with autologous cells from the patient. However, mature cardiomyocytes (CM) rarely proliferate. This research examined the ability of primary pediatric cardiac cells (PPCC) isolated from pediatric CHD biopsy samples supplied by Texas Children’s Hospital to differentiate into CM or induce CM differentiation in stem cells. Previous studies indicated evidence of cardiogenesis in Amniotic fluid-derived stem cells (AFSC) when directly mixed with neonatal rat ventricle myocytes. We hypothesized that co-culturing with human PPCC will induce cardiac differentiation in human AFSC (hAFSC). hAFSC co-cultured in contact with PPCC showed a statistically significant increase in cTnT expression compared to non-contact conditions but did not have functional or morphological characteristics of mature cardiomyocytes. This result suggests that contact is a necessary but not sufficient condition for AFSC cardiac differentiation in co-culture with PPCC. Cardiac progenitor cells (CPC) are proliferating cells with the ability to differentiate into cardiac cells. CPC can be identified from cardiac cells by the expression of Isl-1, SSEAs, and c-Kit. We hypothesized that there are potential CPC in PPCC. We found a small subpopulation (1%-4%) of the primary cells expressing Isl-1, SSEA-4, and c-Kit. However, when exposed to oxytocin, PPCC did not differentiate into functional CM as shown with murine CPC in literature. Extracellular matrix proteins isolated from adult cardiac tissue have been shown to promote CM maturation in vitro. PPCC can be expanded in vitro and cultured in PEGylated fibrin hydrogels. PPCC conditioned gels can then be decellularized. We found that PPCC could be cultured in fibrin hydrogels and that stem cell derived CM were viable when cultured on these conditioned gels. Overall, this research demonstrated that PPCC are a potential tool for CM differentiation and maturation in the development of a tissue engineered cardiac patch for repair of CHD.