Enhanced cytokine production from human macrophages stimulated by polyethylene particles retrieved from interface membranes after failed total hip arthroplasty

Abstract

Little is known about the specific effects of the ultra-high molecular weight polyethylene (UHMWP) debris that is obtained from human interface membranes after revision for a failed total hip arthroplasty. This paper reports the effects of retrieved polyethylene particles on human monocyte/macrophages (M/M). Macrophages were prepared from normal human peripheral blood by the conventional Ficoll–Hypaque method. Polyethylene wear debris was obtained from human interface membranes and prepared by the method of papain digestion. Human M/M were dispensed at 1.0 × 106 cells/well in a 24-well culture plate. UHMWP and latex particles were added immediately after plating the cells and directly onto the cells (1 × 106 cells/well) at final particle concentrations of 100 μg/well, 200 μg/well, and 500 μg/well. At the end of 24 h incubation, the culture supernatant was removed and assayed for IL-1β, IL-6, and TNF-α activities by ELISA. Cellular morphology and architecture were studied using light and electron microscopy. Human M/M cultured with retrieved UHMWP particles caused significantly more IL-1β, IL-6, and TNF-α release than macrophages cultured with latex (P < 0.05). The addition of latex and polyethylene particles to human M/M resulted in a dose-dependent increase in IL-1β, IL-6, and TNF-α release. Electron microscopy revealed that 90% of the UHMWP particles were less than 1 μm diameter. The average particle size was approximately 0.7 μm diameter (range 0.1–15 μm). Human M/M exposed to PE particles demonstrated extensive filopodia formation as compared with the cells exposed to latex particles. In summary, we have demonstrated that polyethylene particles isolated from interfacial membranes obtained at revision surgery are potent stimulators of human M/M.