Engineered Microvasculature in PDMS Networks Using Endothelial Cells Derived from Human Induced Pluripotent Stem Cells

Abstract

In this study, we used a polydimethylsiloxane (PDMS)-based platform for the generation of intact, perfusion-competent microvascular networks in vitro. COMSOL Multiphysics, a finite-element analysis and simulation software package, was used to obtain simulated velocity, pressure, and shear stress profiles. Transgene-free human induced pluripotent stem cells (hiPSCs) were differentiated into partially arterialized endothelial cells (hiPSC-ECs) in 5 d under completely chemically defined conditions, using the small molecule glycogen synthase kinase 3β inhibitor CHIR99021 and were thoroughly characterized for functionality and arterial-like marker expression. These cells, along with primary human umbilical vein endothelial cells (HUVECs), were seeded in the PDMS system to generate microvascular networks that were subjected to shear stress. Engineered microvessels had patent lumens and expressed VE-cadherin along their periphery. Shear stress caused by flowing medium increased the secretion of nitric oxide and caused endothelial cells s to align and to redistribute actin filaments parallel to the direction of the laminar flow. Shear stress also caused significant increases in gene expression for arterial markers Notch1 and EphrinB2 as well as antithrombotic markers Kruppel-like factor 2 (KLF-2)/4. These changes in response to shear stress in the microvascular platform were observed in hiPSC-EC microvessels but not in microvessels that were derived from HUVECs, which indicated that hiPSC-ECs may be more plastic in modulating their phenotype under flow than are HUVECs. Taken together, we demonstrate the feasibly of generating intact, engineered microvessels in vitro, which replicate some of the key biological features of native microvessels.

Shear Stress Promotes Arterial Endothelium-Oriented Differentiation of Mouse-Induced Pluripotent Stem Cells

“…Multiple groups have demonstrated the possible therapeutic benefits of using stem cell-derived ECs for treating diseases, including hind limb ischemia, myocardial infarction, and long-term survival after graft implantation [37, 50–52]. This study demonstrated that exposure to appropriate shear stress enhanced mouse iPSCs towards arterial ECs via Notch signaling pathways.…”

“…Furthermore, distinct differences were observed in the Matrigel assay, including more tube numbers and longer tube length appearing to be fairly functionally mature cells with an arterial-like phenotype [22]. Additionally, cells could align parallel to the direction of flow, demonstrating flow-sensing ability similar to in vivo vessels [37]. Lastly, shear stress upregulated the amount of NO secretion.…”

EndOxy: Mid‐term stability and shear stress resistance of endothelial cells on PDMS gas exchange membranes

“…Despite various advantages for application in biohybrid lung assist, PDMS is known to be hydrophobic and a surface material that naturally does not promote endothelial cell adhesion 17 . Other groups already succeeded in endothelial cell coating of PDMS surfaces of different geometries 29,30 . For proteins as a PDMS surface coating, there are disadvantages for long‐time application like proteolysis, denaturation, or conformational changes described 17 .…”

Analysis of adhesion kinetics of cancer cells on inflamed endothelium using a microfluidic platform

“…The hMEVC endothelium-on-chip developed can be further improved and validated by confirmation of molecular markers such as VE-cadherin (vascular endothelial cadherin) and selective permeability, although we confirmed the confluency of endothelial cells using membrane staining. Incorporation of soft substrates such as PDMS 48 and collagen matrices 14 will provide hMVEC with more in vivo-like environment than rigid glass slide. Moreover, collagen matrices will also allow full observation of TEM of cancer cells.…”