Vascular cell responses to polysaccharide materials: in vitro and in vivo evaluations

Chitosan has shown promise as a structural material for a number of tissue engineering applications. Similarly the glycosaminoglycans (GAGs) and their analogs have been known to exert a variety of biological activities. In this study we evaluated the potential of GAG-chitosan and dextran sulfate (DS)-chitosan complex materials for controlling the proliferation of vascular endothelial (EC) and smooth muscle cells (SMC). GAG-chitosan complex membranes were generated in vitro and seeded with human ECs or SMCs for culture up to 9d. In addition, porous chitosan and GAG-chitosan complex scaffolds were implanted subcutaneously in rats to evaluate the in vivo response to these materials. The results indicated that while chitosan alone supported cell attachment and growth, GAG-chitosan materials inhibited spreading and proliferation of ECs and SMCs in vitro. In contrast, DS-chitosan surfaces supported proliferation of both cell types. In vivo, heparin-chitosan and DS-chitosan scaffolds stimulated cell proliferation and the formation of a thick layer of dense granulation tissue. In the case of heparin scaffolds the granulation layer was highly vascularized. These results indicate that the GAG-chitosan materials can be used to modulate the proliferation of vascular cells both in vitro and in vivo.