title: Early immunomodulatory effects of linezolid in a human whole blood endotoxin model.
abstract: Gram-negative sepsis resulting in endotoxin triggered septic shock is one of the leading causes of death in critically ill patients. Because treatment options are limited, recent approaches focus on immunomodulatory effects of antimicrobials. Thus, we characterized the immunomodulatory effects of linezolid at mRNA and on cytokine levels in supernatants of an ex vivo model of endotoxemia. Whole blood from 10 healthy volunteers was incubated with 50 pg/ml LPS with or without 13 microg/ml linezolid (concentrations were chosen to reflect in vivo conditions) for 2 and 4 hours (h). Quantitative real-time PCR was performed from messenger RNA (mRNA) of IL-1beta;, IL-6, IL-8 or TNF-alpha;. Cytokine levels in the supernatant were measured by ELISA for IL-6, IL-8 and TNF-alpha;. Incubation of human whole blood with LPS increased mRNA levels of cytokines several thousand fold compared with baseline. The addition of linezolid significantly reduced mRNA levels of IL-1beta, IL-6, IL-8 and TNF-alpha; (p < 0.05) after 2 and 4 h. LPS stimulation also increased levels of IL-6, IL-8 and TNF-alpha between 100 and 1000-fold. However, in contrast to mRNA - except for IL-6 - no significant reduction at protein level was observed. These results indicate that immunosuppressive effects of linezolid on mRNA transcription are only partially reflected by cytokine release.
authors.affiliation: 1Internal Medicine II, Department of Respiratory Medicine, Medical University Vienna, Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Lambers
authors.forename: B
authors.initials: B
authors.lastname: Burian
authors.forename: P
authors.initials: P
authors.lastname: Binder
authors.forename: H-J
authors.initials: HJ
authors.lastname: Ankersmit
authors.forename: C
authors.initials: C
authors.lastname: Wagner
authors.forename: M
authors.initials: M
authors.lastname: Müller
authors.forename: M
authors.initials: M
authors.lastname: Zeitlinger
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D016207:Cytokines / Q000235:genetics; D019446:Endotoxemia / Q000188:drug therapy / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D000069349:Linezolid; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D023303:Oxazolidinones / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D000081:Acetamides; D016207:Cytokines; D007166:Immunosuppressive Agents; D008070:Lipopolysaccharides; D023303:Oxazolidinones; D012333:RNA, Messenger; D000069349:Linezolid