title: Toll-like receptor 4 mediates endothelial cell activation through NF-κB but is not associated with endothelial dysfunction in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate the effects of TLR4 antagonism on human endothelial cells activation and cytokine expression, and whether the Asp299Gly TLR4 polymorphism is associated with better endothelial function in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  Human aortic endothelial cells (HAECs) were treated with lipopolysaccharide (LPS), OxPAPC, and free fatty acids (FFA) at baseline and after incubation with the TLR4 antagonist eritoran (E5564). Cytokine expression was assessed by quantitative real-time PCR. In vivo endothelial function was assessed as brachial artery flow-mediated dilation (FMD) in RA patients with the wild type gene (aa) and with the Asp299Gly TLR4 polymorphic variant (ag).
  
  
  RESULTS
  In HAEC, TLR4 antagonism with eritoran inhibited LPS-induced mRNA expression of IL-6, IL-8, TNFα, CCL-2, VCAM and ICAM (P<0.05 for all) and inhibited Ox-PAPC-induced mRNA expression of IL-8 (P<0.05) and IL-6, albeit not to a statistically significant level (p = 0.07). In contrast, eritoran did not affect FFA-induced mRNA expression of IL-6 (P>0.05). In 30 patients with RA (15 with the ag allele) undergoing measurement of FMD, no differences in FMD and plasma levels of IL-6, IL-8, VCAM, and ICAM were found between the aa and the ag phenotype (P>0.05 for all).
  
  
  CONCLUSIONS
  TLR4 signaling in endothelial cells may be triggered by LPS and oxidized phospholipids, leading to endothelial activation and inflammation, which are inhibited by eritoran. Our in vivo investigation, however, does not support an association between the Asp299Gly TLR4 polymorphism and improved endothelium-dependent vasodilator function in patients with RA. Further study is needed to better understand the potential role of TLR4 on endothelial dysfunction in this and other patient populations.
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Menghini
authors.affiliation: Division of Cardiology, MedStar Heart Institute, Washington, DC, United States of America.
authors.forename: Umberto
authors.initials: U
authors.lastname: Campia
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy.
authors.forename: Manfredi
authors.initials: M
authors.lastname: Tesauro
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Marino
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Rovella
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rodia
authors.affiliation: Department of Internal Medicine, Catholic University Medical School, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Schinzari
authors.affiliation: Department of Rheumatology, Catholic University Medical School, Rome, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Tolusso
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: di Daniele
authors.affiliation: Department of System Medicine, University of Tor Vergata, Rome, Italy; Center for Atherosclerosis, Policlinico Tor Vergata, Rome, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Federici
authors.affiliation: Department of Rheumatology, Catholic University Medical School, Rome, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Zoli
authors.affiliation: Department of Rheumatology, Catholic University Medical School, Rome, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Ferraccioli
authors.affiliation: Department of Internal Medicine, Catholic University Medical School, Rome, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Cardillo
mesh_terms: D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001172:Arthritis, Rheumatoid / Q000503:physiopathology*; D002478:Cells, Cultured; D004187:Disaccharides / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D013403:Sugar Phosphates / Q000494:pharmacology; D051197:Toll-Like Receptor 4 / Q000502:physiology*
chemical_list: D004187:Disaccharides; D008070:Lipopolysaccharides; D016328:NF-kappa B; D013403:Sugar Phosphates; D051197:Toll-Like Receptor 4; C512420:eritoran