title: Induced chronic hypoxia negates the pro-angiogenic effect of surface immobilized heparin in a polyurethane porous scaffold.
abstract: Porous scaffolds are frequently utilized in tissue regeneration. We have developed a polyurethane (PU) scaffold with a freely interconnecting porosity that can be modified with a covalently linked heparinized surface. The ability of this surface functionality to stimulate vessel and cellular growth into the PU scaffold has been evaluated by subcutaneous implantation of discs in the rat under normoxia and chronic hypoxia (hypobaric chamber) for 10 days. The heparinized surface alone was able to significantly increase vascularization and cellularization under normoxia (p < 0.05), but this response was negated by hypoxia. Addition of vascular endothelial growth factor to heparinized discs resulted in increased vascularity and cellularization under both conditions (p < 0.05). This suggests that endogenous growth factor production was limiting under chronic hypoxia but that an angiogenic response could still occur with exogenous delivery of factors.
authors: Cardiovascular Research Unit, University of Cape Town, South Africa.
authors: Christian
authors: C
authors: Schmidt
authors: Deon
authors: D
authors: Bezuidenhout
authors: Lawrence
authors: L
authors: Higham
authors: Peter
authors: P
authors: Zilla
authors: Neil H
authors: NH
authors: Davies
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D006493:Heparin / Q000737:chemistry / Q000494:pharmacology*; D000860:Hypoxia / Q000378:metabolism*; D020007:Implants, Experimental; D008297:Male; D008422:Materials Testing; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D011140:Polyurethanes / Q000737:chemistry*; D016062:Porosity; D051381:Rats; D017208:Rats, Wistar; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes; D042461:Vascular Endothelial Growth Factor A; D006493:Heparin