title: Myeloperoxidase (MPO) may mediate neutrophil adherence to the endothelium through upregulation of CD11B expression--an effect downregulated by taurine.
abstract: Extracellular myeloperoxidase (MPO) is a macrophage modulator which stimulates release of the pro-inflammatory cytokine TNF alpha in addition to reactive oxygen species (ROS) generated by these cells. MPO-induced macrophage secretion of pro-inflammatory mediators indirectly upregulates neutrophil pro-inflammatory capacity through contributing to neutrophil priming for respiratory burst activity. However, to date the question concerning a direct influence on the neutrophil by MPO or the MPO-derived product hypochlorous acid (HOCl) remains to be elucidated. Taurine, the most abundant free amino acid in human neutrophils acts as an antioxidant through the formation of taurine-chloramine by sequestering HOCl. Zinc also has antioxidant properties and taurine-zinc complexes have been shown to have greater efficacy than either agent alone in protection against ROS-mediated tissue damage. The aims of this study were: (a) to determine if extracellular MPO modulates the inflammatory response through autocrine feedback on the neutrophil and to investigate if taurine either directly or indirectly through taurine-chloramine formation may further influence this pathway and (b) to evaluate the efficacy of a taurine-zinc combination in modulating MPO-induced CD11b receptor expression.
authors.affiliation: Royal College of Surgeons in Ireland, Department of Surgery, Beaumont Hospital, Dublin, Ireland.
authors.forename: P P
authors.initials: PP
authors.lastname: Stapleton
authors.forename: H P
authors.initials: HP
authors.lastname: Redmond
authors.forename: D J
authors.initials: DJ
authors.lastname: Bouchier-Hayes
mesh_terms: D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D016177:Macrophage-1 Antigen / Q000096:biosynthesis*; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D009195:Peroxidase / Q000502:physiology*; D013654:Taurine / Q000494:pharmacology*; D015854:Up-Regulation; D015032:Zinc
chemical_list: D016177:Macrophage-1 Antigen; D013654:Taurine; D009195:Peroxidase; D015032:Zinc