The effect of phosphorylcholine-coated materials on the inflammatory response and fibrous capsule formation: in vitro and in vivo observations

Abstract

Several experiments were performed to compare the in vitro adhesion of human macrophage and granulocyte inflammatory cells to polyethylene terephthalate substrate and the same coated with a phosphorylcholine (PC)-based polymer. The inclusion of various types of serum at different stages in the assay indicated that protein adsorption and passivation of the surface may be responsible for reducing the number of inflammatory cells adhering to the uncoated polyethylene terephthalate controls. In all of the assays performed there was a statistically significant reduction (p < 0.05; analysis of variance) of the number of inflammatory cells adhering to the PC-coated samples, linked to the ability of these surfaces to resist protein adhesion. Implantations of PC-coated stainless steel and high-density polyethylene USP control samples were made in a rabbit intramuscular model. Histological examination of the number of inflammatory cells present around the implant sites 4 weeks postimplantation showed there were 40% less cells associated with the PC-coated samples compared with control, but this was not statistically significant. Fibrous capsule thickness, however, whereas marginally less at 4 weeks, had almost completely regressed for the PC-coated sample at 13 weeks postimplantation and was statistically thinner (p < 0.01; Mann-Whitney U test) than the high-density polyethylene USP control. These findings support the view that low biointeractions observed for PC-based technology in vitro can result in reduced inflammation and foreign body reaction in vivo.