CoNiCrMo Particles, but Not TiAlV Particles, Activate the NLRP3 Inflammasome in Periprosthetic Cells

Abstract

Aseptic loosening is the main reason for arthroplasty failure. The wear particles generated at the tribological bearings are thought to induce an inflammatory tissue response, leading to bone loss and the subsequent loosening of the implant. Different wear particles have been shown to activate the inflammasome, thereby contributing to an inflammatory milieu in the direct vicinity of the implant. The aim of this study was to investigate whether the NLRP3 inflammasome is activated by different metal particles in vitro and in vivo. Three different cell lines representing periprosthetic cell subsets (MM6, MG63 and Jurkat) were incubated with different amounts of TiAlV or CoNiCrMo particles. The activation of the NLRP3 inflammasome was determined through the detection of the caspase 1 cleavage product p20 in a Western blot. The formation of the inflammasome was also investigated in vivo using immunohistological staining for ASC in primary synovial tissues as well as tissues containing TiAlV and CoCrMo particles and in vitro after the stimulation of the cells. The results show that the CoCrMo particles induced ASC more markedly, as a readout for inflammasome formation in vivo, compared to TiAlV particular wear. The CoNiCrMo particles also induced ASC-speck formation in all the tested cell lines, which was not induced by the TiAlV particles. The Western blot shows that NRLP3 inflammasome activation, measured through caspase 1 cleavage, was increased only by the CoNiCrMo particles in the MG63 cells. We conclude from our data that the activation of the inflammasome is mainly driven by CoNiCrMo particles and less by TiAlV particles, indicating that different inflammatory pathways are activated by the different alloys.

Influence of metallic particles and TNF on the transcriptional regulation of NLRP3 inflammasome-associated genes in human osteoblasts

“…While exposure to CoCr led to slightly increased NLRP3 mRNA levels in osteoblasts over time, macrophages showed an unchanged response to wear particles alone ( 4 ). These changes in expression could be related to the material of the particles, as it has already been established that in addition to the particle dose, the particles’ chemical composition can also influence inflammasome activation ( 4 , 21 , 46 ). It has been described that especially molybdenum in particulate ( 4 , 47 ) but also the ionic ( 47 , 48 ) form can lead to inflammasome induction in macrophages, while cobalt and chromium have only a minor influence ( 47 ).…”

“…Phagocytosis of particles, especially large and irregularly shaped particles ( 9 ), destabilizes the lysosomal membrane, resulting in the release of cathepsin B ( 13 , 53 ). The CoCr particles used in this study had a flaky, cauliflower-like shape and an average size of 500 nm ( 54 ), making them phagocytizable ( 21 , 55 ). The uptake of particles after osteoblasts was investigated using hyperspectral darkfield microscopy.…”

“…This study aimed to use short-term experiments to investigate the time required for human osteoblasts to take up metallic particles derived from cobalt-chromium alloy (CoCr) after initial contact and to initiate a molecular biological response. Since it has already been shown that osteoblasts can form the NLRP3 inflammasome ( 21 , 22 ), the question arose to which extent particles have an impact on the inflammasome. Moreover, it is highly interesting whether particles can prime independently or whether a separate priming signal is required.…”

Emerging factors affecting peri‐implant bone metabolism

“…An in vitro study observed that TiAlV did not activate inflammasome-driven inflammatory reaction, while CoCrMo particles promoted marked activation. 212 Other study found that Cr 3+…”

“…Certain metallic particles can induce activation with higher intensity. An in vitro study observed that TiAlV did not activate inflammasome‐driven inflammatory reaction, while CoCrMo particles promoted marked activation 212 . Other study found that Cr 3+ and Ni 2+ induced an intense inflammasome activation, whereas Co had no or limited effects in this pathway 198 …”