Highly crosslinked vs conventional polyethylene particles--an in vitro comparison of biologic activities.
Highly cross-linked polyethylenes (HXPEs) have been introduced to reduce wear after hip arthroplasty. The improved wear characteristics of HXPEs are well documented, but the relative biologic activity of HXPE and conventional polyethylene (CPE) particles remains unclear. Longevity (Zimmer, Warsaw, Ind; HXPE) and GUR 1050 (Zimmer; CPE) particles were isolated and characterized from a hip simulator and their in vitro inflammatory responses (tissue necrosis factor *, interleukin 1*, and vascular endothelial growth factor levels) were compared using macrophages. The average diameter of Longevity particles (0.111 microm) was smaller than CPE particles (0.196 microm), and both were predominantly round (granular appearance). The inflammatory response to HXPE and CPE was concentration-dependent. No statistically significant differences were noted at low (0.1 surface area ratio [SAR]) and intermediate (0.75 SAR) doses. At the highest dose tested (2.5 SAR), HXPE was significantly more inflammatory than CPE based on relative tissue necrosis factor alpha and vascular endothelial growth factor secretion levels. Further study is needed to determine if similar findings would be noted in vivo over a broad concentration range.
Department of Orthopedics and Rehabilitation, School of Medicine, and Public Health, University of Wisconsin, Madison, Wisconsin 53792, USA.
Richard Lynn
RL
Illgen
Todd M
TM
Forsythe
J Wesley
JW
Pike
Michel P
MP
Laurent
Cheryl R
CR
Blanchard
D000180:Acrylic Resins / Q000494:pharmacology*; D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D002417:Cattle; D002460:Cell Line; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006621:Hip Joint / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D053582:Interleukin-1alpha / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008422:Materials Testing / Q000379:methods*; D051379:Mice; D008855:Microscopy, Electron, Scanning; D010014:Osteolysis / Q000517:prevention & control; D052638:Particulate Matter; D011095:Polyethylenes / Q000737:chemistry / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D000180:Acrylic Resins; C477624:GUR 1050 resin; D053582:Interleukin-1alpha; D052638:Particulate Matter; D011095:Polyethylenes; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A