title: The influence of Co-Cr and UHMWPE particles on infection persistence: an in vivo study in mice.
abstract: Wear of metal-on-metal (cobalt-chromium, Co-Cr particles) and metal-on-polyethylene (ultra-high-molecular-weight polyethylene, UHMWPE particles) bearing surfaces in hip prostheses is a major problem in orthopedics. This study aimed to compare the influence of Co-Cr and UHMWPE particles on the persistence of infection. Bioluminescent Staphylococcus aureus Xen36 were injected in air pouches prepared in subcutaneous tissue of immuno-competent BALB/c mice (control), as a model for the joint space, in the absence or presence of Co-Cr or UHMWPE particles. Bioluminescence was monitored longitudinally up to 21 days, corrected for absorption and reflection by the particles and expressed relative to the bioluminescence found in the presence of staphylococci only. After termination, air pouch fluid and air pouch membrane were cultured and histologically analyzed. Bioluminescence was initially lower in mice exposed to UHMWPE particles with staphylococci than in mice injected with staphylococci only, possibly because UHMWPE particles initially stimulated a higher macrophage presence in murine air pouch membranes. For mice exposed to Co-Cr particles with staphylococci, bioluminescence was observed to be higher in two out of six animals compared to the presence of staphylococci alone. In the majority of mice, infection risk in the absence or presence of Co-Cr and UHMWPE particles appeared similar, assuming that the longevity of an elevated bioluminescence is indicative of a higher infection risk. However, the presence of Co-Cr particles yielded a higher bioluminescence in two out of six mice, possibly because the macrophage degradative function was hampered by the presence of Co-Cr particles.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Anton H
authors.initials: AH
authors.lastname: Hosman
authors.forename: Sjoerd K
authors.initials: SK
authors.lastname: Bulstra
authors.forename: Jelmer
authors.initials: J
authors.lastname: Sjollema
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.forename: Daniëlle
authors.initials: D
authors.lastname: Neut
mesh_terms: D000818:Animals; D002858:Chromium Alloys / Q000009:adverse effects*; D007595:Joint Prosthesis / Q000382:microbiology*; D008163:Luminescent Measurements; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011095:Polyethylenes; D013203:Staphylococcal Infections
chemical_list: D002858:Chromium Alloys; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene