Molecular approaches to the characterization of cell and blood/biomaterial interactions

In order to address questions related to cell/biomaterial interactions with respect to cell function and production of extracellular matrix proteins that support or maintain cell/tissue specific properties, we have developed molecular approaches for analysis of in vivo implanted materials and in vitro studies. In an explant of a human left ventricular assist device (LVAD), intact total cellular RNA could be isolated in sufficient quantities for hybridization analyses with gene-specific probes to evaluate cell growth, cytoskeletal organization, and production of extracellular matrix proteins. Cells harvested from a 132-day implanted LVAD exhibited proliferative activity and expressed genes for fibronectin and collagen types I, III, and IV. In vitro studies revealed that endothelial cells cultured on two different segmented polyurethane biomaterials (Biomer and Tecoflex 60D) exhibited different patterns of gene expression that reflected differences in cell growth rates, morphology, and composition of the extracellular matrix. These methodologies provide a valuable approach for a detailed evaluation of: (1) the biocompatibility of cells colonizing implanted cardiac assist devices; and (2) the functionality of cells seeded onto biomaterials.