Effects of gelsolin on macrophage inflammatory responses to orthopaedic implant wear debris

The local effects of implant wear debris on surrounding tissue has been a major focus of many investigators. Although there have been improvements in implants, significant numbers of revision surgeries are performed to address these issues. Gelsolin (GSN) is a protein in the cytoplasm and circulating serum involved in actin breakdown as well as anti-inflammatory processes. In this study, we tested the hypothesis that GSN in the presence of wear debris in vitro decreases the inflammatory response of a human monocyte cell line. We utilized titanium-, polyethylene-, and cobalt-characterized wear particles in a 1:100 and a 1:500 cell-to-particle ratios in the presence of a low (0.2 µM) and normal (2.0 µM) concentrations of GSN and compared the inflammatory response to cells without GSN exposure. The results show that IL-6, IL-1, TNF-α, and PGE₂ all increased with higher concentrations of GSN. Although the anti-inflammatory properties of GSN were not seen in this in vitro experiment, it has previously been shown that GSN does affect the inflammatory response of monocytes to orthopedic implant wear debris. The dose-response curve for GSN may have a bimodal profile, which should be further investigated.