Abstract 17575: Direct Investigation of Hemodynamic Flow on the Microvascularization of Human Induced Pluripotent Stem Cell Derived Vascular Cells
Background Hemodynamic fluid flow has been known to be a crucial regulator of vascular development and vascular regeneration after injury. Flow and associated shear stress generated by blood flow modulate endothelial cell (EC) function and smooth muscle cell (SMC) function indirectly. However, probing the impact of these forces in vascular development has heretofore been difficult. Here, we utilize human induced pluripotent stem cell (hiPSC) derived vascular cells in a 3D biomimetic flow bioreactor to test the hypothesis that both co-culture and fluid shear stress have a synergistic effect on network formation, angiogenic growth factor secretion and overall in vitro microvascularization.
Methods and Results We have established multiple hiPSC clones containing Cre-excisable transgenes from primary aortic SMCs from a healthy male donor along with a PCR-based assay for screening transgene-free hiPSCs. We used an embryoid body (EB) differentiation approach to induce hiPSCs toward SMC and EC lineage, resulting in the production of highly homogenous (>97%) SMC-like cells that express calponin and ECs that express CD31, VE-Cadherin and vWF. Collagen gel suspensions containing 3 million hiPSC-ECs/ml (or, for co-culture experiments a 1:1 ratio of hiPSC-EC:hiPSC-SMC) were seeded onto porous polyethylene-terephthalate (PET) membranes, allowed to polymerize, secured in bioreactor chamber and perfused with culture medium at a flow rate of 5 ml/min (approx. 5 dyns/cm2, microcirculation pressure) for 2-6 days. Pressure measurements allowed direct calculation of the substrate permeability and applied shear stress. Preliminary results demonstrated that flow promotes increased microvessel formation as well as stress fiber formation in hiPSC-EC; co-culture with hiPSC-SMCs exhibits an overall synergistic effect. Additionally, we observed that fluid flow modulates PDGF-BB and VEGF secretion by hiPSC-ECs.
Conclusion In summary, we are able to use a physiologically relevant cell source to elucidate the effects of hemodynamic flow on microvascular formation and tissue vascularization in vitro. Ultimately, using patient-specific hiPSCs, functional changes during disease development, such as ischemia and aneurysm, can be elucidated using this system.
- © 2012 by American Heart Association, Inc.