Isolation and differentiation of porcine progenitor cells into endothelial-like cells for vascular tissue engineering

Tissue engineered vascular grafts may one day provide a solution to many of the limitations associated with the use of synthetic vascular grafts and vein autografts. In order for vascular tissue engineering to become a clinical reality, scaffolds and cell sources that meet rigorous scientific as well as social criteria will be required. Several laboratories have been investigating various scaffold materials and cell sources in an attempt to meet the requirements of an ideal vascular graft [1-5]. Approaches involve the use of either primary endothelial cells from biopsies or the differentiation of adult stem cells into endothelial-like cells to cover the scaffold [6]. One potential source of mature endothelial cells is adult stem cells found in circulating peripheral blood. Endothelial progenitor cells (EPC) are released into circulating peripheral blood where they contribute to the process of adult vasculogenesis and vascular homeostasis [7]. EPCs have been found in canine [8], ovine [5], and human [9] peripheral blood and mostly studied in the context of cardiac tissue repair. However, there are few studies on the interactions of these cells with biomaterials for potential application in vascular tissue engineering. Our laboratory has been developing elastomeric and biodegradable scaffolds that are based on poly(diol citrates) and investigating their interaction with vascular cells [10, 11]. Herein, we describe the isolation and characterization of EPCs from porcine peripheral blood and their potential to create a functional endothelium on poly (diol citrates). The pig was chosen as the model system because it is commonly used for vascular research due to the size, physiological, and mechanical similarities to humans.