Biocompatibility of porcine small intestinal submucosa and rat endothelial progenitor cells in vitro.

OBJECTIVE This study investigated the biocompatibility of the small intestinal submucosa (SIS) and endothelial progenitor cells (EPCs) by co-cultivating EPCs and SIS in vitro and observing EPC growth on the SIS. METHODS The porcine SIS was prepared and bone marrow mononuclear cells (BMMNCs) were isolated from 3 or 4-week old male SD rats. Cellular morphology was observed by light microscopy and scanning electron microscopy (SEM) and viabilities by the MTT assays. Endothelial progenitor cells (EPCs) were phenotyped by immunocytochemistry, immunofluorescence microscopy and flow cytometry. Vascular lumen formation was evaluated by the Matrigel tube formation assays. EPCs were seeded onto the SIS and production of angiogenin-1 and endothelial cell growth factor (VEGF) by EPCs was examined by ELISA and immunoblotting assays. RESULTS Light microscopy and SEM showed that the mechanically and chemically treated small intestinal submucosa was composed of cell-free extracellular matrix. Immunohistochemistry, and flow cytometry revealed that the EPCs expressed appropriate surface markers including CD34, CD133, and VEGFR-2. Furthermore, the EPCs formed lumen-like structures and the SIS significantly enhanced the growth of EPCs in vitro. CONCLUSION SIS has good biocompatibility with EPCs. SIS pre-seeded with EPCs can be potentially applied as an alternative scaffold material in artificial blood vessel prosthesis.