Expression of Inflammatory Mediators by Human Macrophages in Response to Particulate Debris In Vitro

This paper reports the induction of proinflammatory mediators in human macrophages in response to orthopedic biomaterial wear particles. Human macrophages from healthy subjects were exposed to titanium alloy and polymethylmethacrylate (PMMA) particles in vitro. Expression of proinflammatory cytokines and matrix metalloproteinases (MMPs) were analyzed biochemically. Titanium alloy particles induced macrophage release of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Titanium alloy and PMMA particles also stimulated macrophage release of monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-lα (MIP-lα) in a dose- and time-dependent manner. Particulate debris also induced increased levels of MMP-1, -2 and -9 in a dose- and time-dependent manner. These data demonstrated that particulate debris induced proinflammatory mediator expression in isolated macrophages. Expression of these mediators by wear debris may accelerate periprosthetic bone resorption and granuloma formation.