Adherence of human saphenous vein endothelial cell monolayers to tissue-engineered biomatrix vascular conduits

This study investigates the adherence and retention under in vitro flow conditions of endothelium grown on the luminal surface of 4-mm-internal-diameter, biomatrix vascular conduits. The biomatrix vascular conduits are produced in living animals and consist of a naturally formed extracellular matrix wall incorporating a polyester mesh. We propose that the microarchitecture of the luminal surface may be conducive to endothelial cell (EC) seeding and to the formation of a firmly adherent endothelium without prior treatment of the surface with cell adhesives. ECs were isolated from segments of human saphenous vein and grown to confluence in a culture. Cultured cells were characterized by morphology and immunocytochemistry with anti-CD31, Von Willebrand factor, smooth muscle actin, cytokeratin, and the lectin Ulex Europaeus agglutinin. After culture, ECs were seeded (1 x 10(6) cell/mL) by rotation onto the luminal surface of 20-cm-long, biomatrix vascular conduits (n = 3). The seeded conduits were incubated for 72 h, and at set time points postseeding (1, 24, 48, and 72 h), the morphology, percentage luminal surface cover, and cell density (cell/cm(2)) were determined from en face preparations and histological cross sections. After 72 h in culture, the seeded conduits were subjected to a nonpulsatile flow for 1 h with culture media. A flow rate of 480 mL/min generated physiological-range shear stresses of 12 dyn/cm(2) on the endothelialized surface. After the flow, the conduits were fixed for histology, and the EC morphology and percentage luminal surface cover were determined. Quantification of the extent of luminal surface endothelialization, preflow and postflow, and cell densities at confluence was performed with digital imaging light microscopy and image analysis software. An analysis of the results demonstrated that confluent EC monolayers may be established on the luminal surface of biomatrix vascular conduits within 48 h. The formed endothelium was firmly adherent and was retained under physiological-range flow.