In vitro modelling of tissue using isolated vascular cells on a synthetic collagen matrix as a substitute for heart valves.

Abstract

Tissue engineering is a promising approach for obtaining lifetime durability in biological heart valves. Basic questions with respect to the selection of suitable cell populations as well as scaffolds remain unsolved. The purpose of this study was to develop a tissue-like substitute in vitro for replacement of diseased valves in vivo. Smooth-muscle cells (SMCs) were isolated from human and porcine aortic tissue using the 'explant technique' and endothelial cells from collagenase digestion. Seeding and cultivation of isolated cells was performed on a type-I collagen matrix. The scaffold-cell specimen was investigated using light and electron microscopy. Cupromeronic blue and immunoprecipitation were used for ultracytochemical staining. SMCs were allowed to grow to multilayers and migrate into the collagen network. We found a tissue-like morphology in these samples characterised by several layers of cells, spaces between the cell layers filled with newly formed extracellular matrix components, compartmentalisation of proteoglycans and their association with fibrilar matrix and the cell surface. Endothelium cells covered the SMCs of the scaffold with a histological topography similar to heart valves. This is an approach for in vitro modelling of tissue-like substitutes and preparing plane multicellular tissues as substitutes for heart valves. This model may also be used for cell biological investigations of cell-matrix interactions.