Vascularization and gene regulation of human endothelial cells growing on porous polyethersulfone (PES) hollow fiber membranes

Open-cell hollow fibers made of polyethersulfone (PES) manufactured in the absence of solvents with pore diameters smaller than 100 microm were examined for vascularization by human endothelial cells. The goal of this study was to determine whether the 3-D porous character of the PES surface affected human endothelial cell morphology and functions. Freshly isolated human endothelial cells from the skin (HDMEC), from the lung (HPMEC) and from umbilical cords (HUVEC) and two human endothelial cell lines, HPMEC-ST1.6R and ISO-HAS.c1 were added to PES fibers and cell adherence and growth was followed by confocal laser scanning microscopy. Prior coating of PES with gelatin or fibronectin was necessary for adhesion and spreading of cells over the uneven porous surface with time. Confluent cells exhibited typical strong PECAM-1 expression at cell-cell borders. Little expression of the activation markers E-selectin, ICAM-1, and VCAM-1 was observed by RT-PCR of endothelial cells growing on PES. However, after stimulation for 4h by LPS, activation of these markers was observed and it was shown by immunofluorescent staining that induction occurred in most of the cells, thus confirming an intact functionality. Finally, cells growing as a monolayer on PES migrated to form microvessel-like structures when placed under conditions that stimulated angiogenesis. Thus, human endothelial cells grown on fibronectin-coated PES fibers retain important endothelial-cell specific morphological and functional properties and PES may serve as a useful biomaterial in tissue engineering and biotechnology applications.