GROWTH-FACTORS AND BIOLOGICAL SUPPORTS FOR ENDOTHELIAL-CELL LINING - IN-VITRO STUDY

Endothelial cell covering over the vascular prosthesis luminal surface is a process that may require the presence of growth factors (GFs) an d extracellular matrix supports. Endothelialization could be improved by combining both GFs and an extracellular matrix analog. In the prese nt study, different biological substrates made of type I or IV collage ns, gelatin, fibronectin, fibrin, laminin, chondroitin sulphate, hepar an sulphate, heparin or hyaluronic acid were used to support endotheli al cell culture. An endothelial cell growth supplement (ECGS) was inco rporated in (group 1) or overlaid on (group 2) the substrates; or pres ent in medium (group 3); or absent (group 4). GF binding assay using I -125 bFGF showed that more GF remained combined to the substrates in g roup 2 than those in group 1. Growth and morphology of human umbilical vein endothelial cells were sequentially analyzed in vitro for 8 days using DNA (nuclei counts) and F-actin labelings. Growth was relativel y stable for the first 48 hours, later in groups 1, 2 and 4, cell deat h was observed on all the substrates except for fibronectin. Growth fa ilure could be related to the degradation or inefficient release of EC GS. In group 3, growth increased and confluency was reached within 5-8 days on all the substrates except for gelatin and type I collagen. Co nfluent cells containing actin filaments were organized on glycoprotei ns and disorganized on glycosaminoglycans and fibrin. Despite that gly coproteins can enhance cell adhesion and lining pattern, GFs continual ly delivered in a fresh soluble form seem to be the appropriate condit ion to obtain an endothelial cell lining.