Polyethylene and titanium particles induce osteolysis by similar, lymphocyte‐independent, mechanisms

Abstract

Periprosthetic osteolysis is a major clinical problem that limits the long-term survival of total joint arthroplasties. Osteolysis is induced by implant-derived wear particles, primarily from the polyethylene bearing surfaces. This study examined two hypotheses. First, that similar mechanisms are responsible for osteolysis induced by polyethylene and titanium particles. Second, that lymphocytes do not play a major role in particle-induced osteolysis. To test these hypotheses, we used the murine calvarial model that we have previously used to examine titanium-induced osteolysis. Polyethylene particles rapidly induced osteolysis in the murine calvaria 5-7days after implantation. The polyethylene-induced osteolysis was associated with large numbers of osteoclasts as well as the formation of a thick periosteal fibrous tissue layer with numerous macrophages containing phagocytosed polyethylene particles. Polyethylene-induced osteolysis was rapidly repaired and was undetectable by day 21 after implantation. Lymphocytes were noted in the fibrous layer of wild-type mice. However, the amount of osteolysis and cytokine production induced by polyethylene particles was not substantially affected by the lack of lymphocytes in PfplRag2 double knock out mice. All of these findings are similar to our observations of osteolysis induced by titanium particles. These results provide strong support for both of our hypotheses: that similar mechanisms are responsible for osteolysis induced by polyethylene and titanium particles and that lymphocytes do not play a major role in particle-induced osteolysis.

Do Tissues From THA Revision of Highly Crosslinked UHMWPE Liners Contain Wear Debris and Associated Inflammation?

“…Importantly, metal wear particles were not observed in patient tissues to account for the presence of T cells. Although animal models have shown T cells are dispensable in the development of osteolysis [25,39,72], a recent in vitro study showed depletion of T cells or the addition of RANK-Fc to human peripheral blood cell cultures equally reduced osteoclast formation in response to RANKL [65]. Additionally, the current findings and those of others [28,61] support the potential involvement of T cells in human osteolytic responses after recruitment by chemotactic factors released from activated macrophages [5,19,63,68].…”

Do Genetic Susceptibility, Toll-like Receptors, and Pathogen-associated Molecular Patterns Modulate the Effects of Wear?

“…Also consistent with the importance of other factors is the finding that monocyte production of proinflammatory cytokines in response to polyethylene and titanium wear particles varies greatly between individual donors [31,46]. The similar finding with different types of particles is not surprising because the different types of particles are thought to induce osteolysis through similar proinflammatory mechanisms [7,75,102,108]. This review focuses on three other factors that may modulate the effects of wear particles: (1) genetic susceptibility; (2) Toll-like receptors (TLRs); and (3) bacterial pathogenassociated molecular patterns (PAMPs).…”

Individual susceptibility to periprosthetic osteolysis is associated with altered patterns of innate immune gene expression in response to pro‐inflammatory stimuli

“…26 However, titanium particles have better handling characteristics versus polyethylene in culture systems and are more readily cleaned of surface contaminants without alteration of the material characteristics of the particle, making them a more reliable and reproducible particulate challenge than polyethylene for in vitro culture systems.…”