Collagen Matrix Scaffold Functionalization Stimulates Viability and Proangiogenic Capability of Human-Induced Pluripotent Stem Cell Derived Vascular Smooth Muscle Cells
Kaiti Duan, Bachelor of Science, Biraja Dash, PhD, Henry C. Hsia, MD.
Yale School of Medicine, New Haven, CT, USA.
BACKGROUND:: Induced-pluripotent-stem-cell-derived-vascular smooth muscle cells (iPSC-VSMC) have the potential to treat chronic wounds by secreting proangiogenic factor vascular endothelial growth factor(VEGF). However, little is known how the extracellular matrix (ECM) composition may impact the cellsí paracrine secretion profile. In this study, our objective was to understand the effects of ECM density and functionalities on the secretory profile of human iPSC-VSMCs.
METHODS: Type-I collagen was used as the material for scaffold density modulations and were incorporated with hyaluronic acid (HA), fibronectin, and laminin functional biomolecules to fabricate different functionalities of collagen scaffolds. The functionalities were used in combination with three different density of type-I collagen (1.25mg/ml, 2.5mg/ml, and 4mg/ml) to study iPSC-VSMCs viability and paracrine secretion profile. Several pro-angiogenetic factors including VEGF, Stromal cell-derived factor (SDF), platelet derived growth factor (PDGF), basal fibroblast growth factor (bFGF), angiopoietin 1 (ANG-1), IL-8, and transforming growth factor (TGF) were investigated. Anti-inflammatory factor IL-10 was also evaluated.
RESULTS: Human iPSC-VSMCs embedded in high collagen density(4mg/ml) scaffolds exhibited significant increase in cell viability as compared to medium(2.5mg/ml) and low(1.25mg/ml) density scaffolds(P-value<0.002 and 0.009 respectively). Augmented VEGF and bFGF secretions were also observed in densest scaffold compared 2.5mg/ml and 1.25mg/ml scaffolds (both P-values<0.0001). All bio-functionalized scaffolds increased cellular viability at 1.25mg/ml and 4mg/ml collagen scaffolds (P-value=0.001 and 0.002, respectively). Fibronectin-functionalized scaffolds at 4mg/ml exhibited substantially elevated bFGF secretion (P value=0.0001). There was also a positive correlation of increasing amount of fibronectin embedment with increasing bFGF paracrine secretion (P-value=0.0001).
CONCLUSIONS:These results suggested high collagen density scaffolds preferentially increased both iPSC-VSMC viability and paracrine capabilities. Bio-functionalized collagen improved iPSC-VSMC viability irrespective of scaffold density and increasing bFGF secretion can be modulated via increasing fibronectin embedment. Future signaling pathway studies and mice model experiments will elucidate the translational regenerative therapy efficacy potential of Human iPSC-VSMCs in these conditioned collagen scaffolds. This will ultimately optimize the use of Human iPSC-VSMCs as a viable therapeutic agent for chronic wound healing.
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