The Interrelation Between the 3D Microenvironment and Mechanis of Human Induced Pluripotent Endothelial Progenitors

Human induced pluripotent stem cells (hiPSCs) offer immense potential for tissue engineering, yet poor vascularization remains a significant hurdle. Understanding how hiPSC-derived endothelial progenitor cells (hiPSC-EPs) form networks is essential for therapeutic progress. This study investigates extracellular matrix (ECM) remodeling and cellular contractility during the early self-assembly of hiPSC-EPs within 3D hyaluronic acid-based hydrogels. By tracking microsphere displacements before and after cytochalasin-D treatment, we quantified contractile forces in single cells and clusters at days 4 and 7. We then applied a novel inverse modeling approach using a compressible material model to determine spatially varying changes in hydrogel modulus caused by enzymatic degradation and ECM deposition. Our findings reveal that basal contractility and remodeling are nonlinearly influenced by multicellularity, culture duration, and initial stiffness. Increased hydrogel stiffness, paired with synergistic rises in strain energy, resulted in high traction forces in longer culture times. These results provide critical mechanical insights into hiPSC-EP self-assembly, advancing our ability to engineer functional vascular networks.