Macrophage polarization in response to wear particles in vitro

Joseph K. Antonios, Zhenyu Yao, Chenguang Li, Allison J. Rao, Stuart B. Goodman

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


Total joint replacement is a highly successful surgical procedure for treatment of patients with disabling arthritis and joint dysfunction. However, over time, with high levels of activity and usage of the joint, implant wear particles are generated from the articulating surfaces. These wear particles can lead to activation of an inflammatory reaction, and subsequent bone resorption around the implant (periprosthetic osteolysis). Cells of the monocyte/macrophage lineage orchestrate this chronic inflammatory response, which is dominated by a pro-inflammatory (M1) macrophage phenotype rather than an anti-inflammatory pro-tissue healing (M2) macrophage phenotype. While it has been shown that interleukin-4 (IL-4) selectively polarizes macrophages towards an M2 anti-inflammatory phenotype which promotes bone healing, rather than inflammation, little is known about the time course in which this occurs or conditions in which repolarization through IL-4 is most effective. The goal of this work was to study the time course of murine macrophage polarization and cytokine release in response to challenge with combinations of polymethyl methacrylate (PMMA) particles, lipopolysaccharide (LPS) and IL-4 in vitro. Treatment of particle-challenged monocyte/macrophages with IL-4 led to an initial suppression of pro-inflammatory cytokines and inducible nitric oxide synthase (iNOS) production and subsequent polarization into an M2 anti-inflammatory phenotype. This result was optimized when IL-4 was delivered before PMMA particle challenge, to an M1 phenotype rather than to uncommitted (M0) macrophages. The effects of this polarization were sustained over a 5-day time course. Polarization of M1 macrophages into an M2 phenotype may be a strategy to mitigate wear particle associated periprosthetic osteolysis.

Original languageEnglish (US)
Pages (from-to)471-482
Number of pages12
JournalCellular and Molecular Immunology
Issue number6
StatePublished - Nov 2013
Externally publishedYes

Bibliographical note

Funding Information:
We would like to thank Dr Alexander Harris of Stanford University for assistance in the statistical analysis. We would also like to thank Dr Stephen Badylak and Brian Sicari for assistance in choosing appropriate macrophage markers. This work was supported by NIH grants 2R01AR055650-05 and 1R01AR063717-01; the Ellenburg Chair in Surgery at Stanford University; and the Stanford Medical Scholars Program.


  • IL-4
  • macrophage polarization
  • osteolysis
  • PMMA particles
  • total joint replacement


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