Construction of vascularized pacemaker tissues by seeding cardiac progenitor cells and endothelial progenitor cells into Matrigel

AimsTransplantation of a tissue engineered cardiac pacemaker (TECP) may represent a novel therapy for cardiac sinus node dysfunction. We previously reported that cardiac progenitor cells (CPCs) derived from embryonic heart tubes could differentiate into cardiac pacemaking cells after endothelin-1 treatment. We aimed to examine the feasibility of TECP fabricated from CPCs-derived pacemaking cells and vascularization of TECP fabricated from CPCs-derived pacemaking cells and endothelial progenitor cells (EPCs) in vitro and in vivo implantation.Main methodsTECP created using CPCs-derived pacemaking cells and vTECP created by mixing CPCs and EPCs in vitro were implanted into rat hearts. Sinus node damaged was induced by formaldehyde insult.Key resultsSpontaneous beating tissues, namely TECP, were obtained after seeding CPCs-derived pacemaking cells into Matrigel. ECG and epicardial multielectrode array (MEA) measurements confirmed implanted TECP have electrical activity. TECP implantation promoted individual survival in sinus node damage models (15/22 animals lived versus 0/17 control). vTECP fabricated by mixing the both EPCs and CPCs-derived pacemaking cells with Matrigel in equal proportions optimally formed pre-vascularization in vitro. The implantation of vTECP enhanced electrical activity in vivo, which may correlate with increased vascularization. PI3K-Akt-VEGF/VEGFR signaling was involved with vascular ingrowth in vTECP.SignificanceOur data supports the therapeutic potential of TECP fabricated with the CPCs-derived pacemaking cells for sinus node dysfunction. Vascularization by the addition of EPCs is an important factor to sustain viability of the TECP in vivo.