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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_8 | Pages 18 - 18
10 May 2024
LACTOFERRIN AS AN ADJUVANT ANTIMICROBIAL IN BATTLEFIELD-RELEVANT OPEN FRACTURES
Joseph R Callon K Lin J Matthews B Irwin S Williams D Ashton N Crawford H Wen J Swift S Cornish J
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Introduction

Major trauma during military conflicts involve heavily contaminated open fractures. Staphylococcus aureus (S. aureus) commonly causes infection within a protective biofilm. Lactoferrin (Lf), a natural milk glycoprotein, chelates iron and releases bacteria from biofilms, complimenting antibiotics. This research developed a periprosthetic biofilm infection model in rodents to test an Lf based lavage/sustained local release formulation embedded in Stimulin beads.

Method

Surgery was performed on adult rats and received systemic Flucloxacillin (Flu). The craniomedial tibia was exposed, drilled, then inoculated with S. aureus biofilm. A metal pin was placed within the medullary cavity and treatments conducted. Lf in lavage solutions: The defect was subject to 2× 50 mL lavage with 4 treatment groups (saline only, Lf only, Bactisure with Lf, Bactisure with saline). Lf embedded in Stimulin beads: 4 bead types were introduced (Stimulin only, Lf only, Flu only, Lf with Flu). At day 7, rats are processed for bioluminescent and X-ray imaging, and tibial explants/pins collected for bacterial enumeration (CFU).

Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_II | Pages 151 - 151
1 Jul 2002
TNFα PRODUCTION IN RESPONSE TO POLYETHYLENE PARTICLES, A POTENTIAL INDICATOR FOR ASEPTIC LOOSENING OF TOTAL HIP ARTHROPLASTY
Alonso JA Matthews B Ingham E Fisher J Shaw D
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Introduction: UHMWPE wear debris is known to be a major cause of periprosthetic osteolysis and the long-term failure of total joint replacements by a macrophage-mediated mechanism. The aim of this study was to compare the in vitro response of mononuclear phagocytes from patients undergoing total hip arthroplasty to challenge with polyethylene particles or stimulation with lipopolysaccharide (LPS).

Methods: Peripheral blood was taken from 2 healthy donors and 16 patients admitted to hospital to undergo total hip arthroplasty. Human mononuclear phagocytes were isolated by density centrifugation. Polyethylene particles were sequentially filtered to obtain biologically active particles (0.1–0.6 μm diameter). Cells plus particles, cells plus LPS and cells only were co-cultured in supplemented RPMI-1640 culture medium. Culture supernatants were harvested and the concentration of TNFα quantified by ELISA. Mean specific activity was calculated.

Results:.

TNFα levels Particle stimulation LPS stimulation
Control 0.043–0.059 0.097–0.208
Patients 0–1.1 0.03–17.693

When considering all the subjects, no correlation was found between the response of their cells to polyethylene particles and LPS stimulation. However the cells of four subjects gave a much higher response to LPS than the rest and when these where excluded the correlation between the response to LPS and PE particles was significant with an R2 value of 0.9076.

Discussion: Despite the different mechanisms by which PE particles and LPS activate macrophages, the patient group with ‘normal’ or low response to LPS had a significant correlation in their response to LPS and particle stimulation. Why a small number of subjects had a much higher response to LPS without a proportional response to PE particles is not known, but it could be due to an increased expression of LPS receptors or genetic polymorphism. A greater than ten-fold difference in the patient response to particles may be of clinical importance in their potential susceptibility to loosening through osteolysis.