title: Macrophage response to high number of titanium particles is cytotoxic and COX-2 mediated and it is not affected by the particle's endotoxin content or the cleaning treatment.
abstract: Periprosthetic osteolysis is a progressive deterioration of bone around prostheses resulting primarily from the presence of wear debris. Particulate material, number, and their interactions with environmental factors play important roles in macrophage activation around implants. We have previously shown that macrophages cultured in the presence of high numbers of cleaned titanium (Ti) particles released significant amounts of PGE₂ that is potentially detrimental for bone. Cleaning of particles has become routine in most studies of macrophage/particle interactions as contaminating endotoxin elicits a macrophage cytokine response and since numerous studies have suggested that endotoxins may be present on implant materials. However, the strenuous cleaning procedure itself represents a possible source of other contaminants (such as material by-products) that may be relevant to the prostanoid response of macrophages. To analyze this hypothesis, the macrophage response to high numbers of cleaned Ti particles was compared to that of unclean particles and to particles that were subjected to a short version of the cleaning procedure. It was found that neither the high amount of endotoxin on the unclean particles nor the duration of the cleaning procedure had an effect on the release of PGE₂ and the decrease in cell viability in response to high number of Ti particles. Evidence of a possible relationship between these two variables is presented.
authors.affiliation: Department of Orthopedic Surgery, Campbell Clinic, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
authors.forename: Luciana P
authors.initials: LP
authors.lastname: Schwab
authors.forename: Justin
authors.initials: J
authors.lastname: Marlar
authors.forename: Karen A
authors.initials: KA
authors.lastname: Hasty
authors.forename: Richard A
authors.initials: RA
authors.lastname: Smith
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D004731:Endotoxins / Q000737:chemistry*; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008422:Materials Testing; D051379:Mice; D010014:Osteolysis / Q000139:chemically induced; D010316:Particle Size; D011475:Prosthesis Failure / Q000009:adverse effects*; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D004731:Endotoxins; D014409:Tumor Necrosis Factor-alpha; D014025:Titanium; D051546:Cyclooxygenase 2; D015232:Dinoprostone