Human vascular endothelial cell attachment and growth inhibition by type V collagen

Abstract

Human vascular prostheses develop a pseudointima that after time is devoid of a complete endothelial lining. The composition of this pseudointima consists of both cellular and noncellular components such as coagulation proteins and extracellular matrix proteins. Of these extracellular molecules, type V collagen has been reported to be localized to surfaces of vascular prostheses. We have hypothesized that type V collagen may be involved in the mechanisms of inhibition of endothelialization on vascular prostheses. In this study, interactions of human protein and cells with clinically used material and reference surfaces were analyzed in vitro. Human collagen types IV and V or human fibronectin was coated on disks punched from expanded polytetrafluoroethylene, bacteriologic polystyrene, and tissue culture-treated polystyrene. Fibronectin adsorbed equally to these surfaces, but differential adsorption of type V collagen occurred. The attachment and growth of human saphenous vein and umbilical vein endothelial cells and of human skin fibroblasts were also evaluated on protein-coated or uncoated surfaces. Type IV collagen and fibronectin promoted the attachment of these cells, but type V collagen reduced cellular adhesion. Growth of endothelial cells was significantly inhibited on surfaces coated with type V collagen even when additional growth substances such as serum, retinal-derived growth factor, and heparin were present in the medium. Human adult dermal fibroblast adhesion and cell growth were not affected by coating the surfaces with type V collagen. The components of the extracellular matrix of the pseudointima may directly influence endothelial cells by inhibiting cell proliferation, migration from within the graft or from anastomoses, or both. Type V collagen, a matrix protein found at luminal surfaces of vascular prostheses, may be one protein responsible for control of endothelial responses.