Cell phenotype characterization in vascular organotypic culture

An in vitro biocompatibility assessment test has been successfully applied to vascular prostheses. It consists of an organotypic culture of chick embryo vascular explant which preserves wall vessel cell interactions and enables cell growth and migration on biomaterial. This study is an attempt to identify the cell phenotype expressed by scanning electron microscopy, by immunostaining with specific monoclonal antibodies against smooth muscle cell (SMC) or von Willebrand factor (vWF), and by uptake of acetylated low-density lipoprotein. Early migrating cells had an endothelial-like phenotype independent of embryonic or adult vessel, veinous or arterial explants. SMC appeared labelled beyond the inner endothelial area. At the periphery, SMC displayed actin bundles specific to stationary phase. Adult cell cultures differed from embryonic cultures in that endothelial-like cells (EC) were more stable and increased their vWF labelling, whereas in embryonic cultures, some EC rounded up with subsequent detachment. Explant culture in liquid instead of agar medium activated this degenerative process suggesting the effect of diffusible chemotactic factors. Organotypic culture in agar medium provides an in vitro co-culture system of EC and SMC and enables further investigation of spatial and temporal evolution of vascular tissues in contact with various substrate.