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 9 d. 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.