title: C1-inhibitor efficiently inhibits Escherichia coli-induced tissue factor mRNA up-regulation, monocyte tissue factor expression and coagulation activation in human whole blood.
abstract: Both the complement system and tissue factor (TF), a key initiating component of coagulation, are activated in sepsis, and cross-talk occurs between the complement and coagulation systems. C1-inhibitor (C1-INH) can act as a regulator in both systems. Our aim in this study was to examine this cross-talk by investigating the effects of C1-INH on Escherichia coli-induced haemostasis and inflammation. Fresh human whole blood collected in lepirudin was incubated with E. coli or ultrapurified E. coli lipopolysaccharide (LPS) in the absence or presence of C1-INH or protease-inactivated C1-INH. C3 activation was blocked by compstatin, a specific C3 convertase inhibitor. TF mRNA was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and TF surface expression was measured by flow cytometry. In plasma, the terminal complement complex, prothrombin F1·2 (PTF1·2) and long pentraxin 3 (PTX3) were measured by enzyme-linked immunosorbent assay (ELISA). Cytokines were analysed using a multiplex kit. C1-INH (1·25-5 mg/ml) reduced both LPS- and E. coli-induced coagulation, measured as a reduction of PTF1·2 in plasma, efficiently and dose-dependently (P < 0·05). Both LPS and E. coli induced marked up-regulation of TF mRNA levels and surface expression on whole blood monocytes. This up-regulation was reduced efficiently by treatment with C1-INH (P < 0·05). C1-INH reduced the release of PTX3 (P < 0·05) and virtually all cytokines measured (P < 0·05). Complement activation was inhibited more efficiently with compstatin than with C1-INH. C1-INH inhibited most of the other readouts more efficiently, consistent with additional non-complement-dependent effects. These results indicate that complement plays a role in activating coagulation during sepsis and that C1-INH is a broad-spectrum attenuator of the inflammatory and haemostatic responses.
authors.affiliation: Department of Laboratory Medicine, Nordland Hospital, Bodø, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Landsem
authors.forename: E W
authors.initials: EW
authors.lastname: Nielsen
authors.forename: H
authors.initials: H
authors.lastname: Fure
authors.forename: D
authors.initials: D
authors.lastname: Christiansen
authors.forename: J K
authors.initials: JK
authors.lastname: Ludviksen
authors.forename: J D
authors.initials: JD
authors.lastname: Lambris
authors.forename: B
authors.initials: B
authors.lastname: Østerud
authors.forename: T E
authors.initials: TE
authors.lastname: Mollnes
authors.forename: O-L
authors.initials: OL
authors.lastname: Brekke
mesh_terms: D001777:Blood Coagulation; D002097:C-Reactive Protein / Q000378:metabolism; D002478:Cells, Cultured; D018920:Coculture Techniques; D003174:Complement C1 Inactivator Proteins / Q000235:genetics / Q000378:metabolism*; D050718:Complement C1 Inhibitor Protein; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D010446:Peptide Fragments / Q000097:blood; D011516:Prothrombin; D012333:RNA, Messenger / Q000032:analysis; D018805:Sepsis / Q000188:drug therapy / Q000276:immunology*; D000683:Serum Amyloid P-Component / Q000378:metabolism; D013925:Thromboplastin / Q000235:genetics / Q000378:metabolism*; D000099153:Pentraxins
chemical_list: D002097:C-Reactive Protein; D003174:Complement C1 Inactivator Proteins; D050718:Complement C1 Inhibitor Protein; D008070:Lipopolysaccharides; D010446:Peptide Fragments; D011516:Prothrombin; D012333:RNA, Messenger; D000683:Serum Amyloid P-Component; D013925:Thromboplastin; D000099153:Pentraxins; C469952:SERPING1 protein, human; C045879:prothrombin fragment 1.2
keywords: C1-inhibitor; coagulation; complement; tissue factor; whole blood