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Titanium particles and surface‐bound LPS activate different pathways in IC‐21 macrophages
Author(s) -
Schwab Luciana P.,
Xing Zhiqing,
Hasty Karen A.,
Smith Richard A.
Publication year - 2006
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30512
Subject(s) - lipopolysaccharide , tumor necrosis factor alpha , macrophage , particle (ecology) , receptor , biophysics , chemistry , osteolysis , cytokine , titanium , cell , bone resorption , materials science , microbiology and biotechnology , immunology , biochemistry , medicine , in vitro , biology , surgery , organic chemistry , ecology
It is still unknown if wear‐debris particles themselves induce osteolysis or if they serve a functional role as receptors for ligands that incite an inflammatory response that ultimately leads to bone resorption. In this study, commercially pure titanium particles (cpTi) were subjected to a serial combination of different cleaning methods to remove Lipopolysaccharide (LPS) or were incubated in LPS solutions of known concentrations. Then, the response of the macrophage cell line IC‐21 to the cleaned particles, LPS‐bound Ti particles, and soluble LPS was examined. It was found that cleaned particles up to 1000 particles per cell did not stimulate macrophages to release Tumor necrosis factor‐alpha (TNF‐α) or Interleukin 6 (IL‐6), but they significantly increased the release of Prostaglandin E 2 (PGE 2 ) when the particle concentration was higher than 500 particles per cell. At one particle per cell, Ti particles bound with LPS stimulated the release of IL‐6 and TNF‐α by macrophages. The level of released cytokines was dependent on, and correlated with, the amount of LPS present on the particles. The macrophages were more sensitive to soluble LPS than to particle‐bound LPS, and the simultaneous addition of cleaned Ti particles did not have additional effects on the effects of soluble LPS. This study shows evidence that, cpTi particles and LPS have distinct mechanisms of action on the IC‐21 macrophages, but that both contribute to the development of an inflammatory response. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006