In situ capture technology of endothelial progenitor cells

Abstract

Purpose: This study aims to develop the surface architecture enabling selective in-situ capturing of endothelial progenitor cells (EPCs) and subsequent rapid endothelialization on blood-contacting surfaces under arterial flow. First, based on ex vivo cellular potentials on various surface-bound candidate ligands, the best-suited pair of cell receptor exclusively expressed on endothelial lineage cells and surface-bound ligand is defined. Second, prolonged activation of intracellular signaling transduction pathways of EPCs adhered on surface-bound ligand is examined. Lastly, in-situ capture of EPCs and endothelialization in a porcein model is verified. Methods: Methods included (1) covalent bonding of molecules [vascular endothelial growth factor (VEGF) and two VEGF receptor antibodies and Tie-1 and -2 antibodies] on vinyl alcoholcopolymer; (2) culture of human mononuclear cells(MCs) on these proteinbound substrates and histocytochemical analyses; and (3) implantation of stent in coronaries. Results: Proteins were covalently bound to the copolymer surface via activation of hydroxyl group. Among molecules examined, only VEGF exhibited high adhesion and proliferation characteristics and a quite high differentiation potential of MCs with culture time. Day-order continuous activation of intracellular signaling transduction pathways (phosphorylation of VEGF receptor, FAK, ERK and Akt) was observed for ECs adhered on VEGF-bound substrate. Implantation study using VEGF-bound stents showed that cells expressing VEGF receptor adhered on stent surface followed by endothelialization was observed within several days. Conclusions: This study concludes that surface-bound VEGF enables selective capture of EPCs and complete endothelialization in vivo, and simple surface architecture promise to exert non-thrombogenic potential to cardiovascular devices.