title: Modulation of nitric oxide and cytokines production by L-arginine in human gut mucosa.
abstract: BACKGROUND
  Arginine is a conditionally essential amino-acid with immuno-modulatory properties, mainly through the nitric oxide (NO) pathway.
  
  
  OBJECTIVE
  To assess the effects of arginine on intestinal production of pro- and anti-inflammatory cytokines and NO in human gut.
  
  
  METHODS
  An enteral solution of arginine or a control solution of amino-acids was administered to 8 healthy volunteers on a randomized cross-over design. Duodenal biopsies were taken. Pro- (IL-6, IL-8) and anti-inflammatory (IL-4, IL-10) cytokines mRNA expression was assessed by RT-PCR. Other biopsies were cultured with 0.1, 0.5 or 2 mM arginine or control amino-acids, under basal or IL-1beta-induced inflammatory conditions. Interleukin-4, IL-6, IL-8 and IL-10 production was measured in culture supernatant by ELISA and NO production by Griess reaction.
  
  
  RESULTS
  Arginine enhanced the production of NO under inflammatory conditions in a dose-dependent manner (P=0.03). IL-1beta increased the production of IL-8 and IL-6 (P<0.01). Arginine had no effect on pro- and anti-inflammatory cytokines production both under basal and inflammatory conditions.
  
  
  CONCLUSIONS
  Arginine enhanced the production of NO but did not affect that of cytokines in inflammatory human gut. Further clinical studies are required to assess whether arginine-enhanced NO production plays a beneficial or deleterious effect in intestinal inflammation.
authors.affiliation: Appareil Digestif Environnement Nutrition (ADEN EA 3234) and Institut Fédératif de Recherches Multidisciplinaires sur les peptides (IFR n 23), CIC-INSERM-CHU, 76031 Rouen Cedex, France. stephanelecleire@hotmail.com
authors.forename: Stephane
authors.initials: S
authors.lastname: Lecleire
authors.forename: Moise
authors.initials: M
authors.lastname: Coeffier
authors.forename: Jonathan
authors.initials: J
authors.lastname: Leblond
authors.forename: Aurelie
authors.initials: A
authors.lastname: Hubert
authors.forename: Sabrina
authors.initials: S
authors.lastname: Lemoulan
authors.forename: Andre
authors.initials: A
authors.lastname: Petit
authors.forename: Philippe
authors.initials: P
authors.lastname: Ducrotte
authors.forename: Pierre
authors.initials: P
authors.lastname: Dechelotte
authors.forename: Rachel
authors.initials: R
authors.lastname: Marion
mesh_terms: D000328:Adult; D001120:Arginine / Q000008:administration & dosage*; D001706:Biopsy; D018592:Cross-Over Studies; D004386:Duodenum / Q000187:drug effects* / Q000276:immunology; D004750:Enteral Nutrition; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000276:immunology*; D007378:Interleukins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000276:immunology; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric
chemical_list: D007378:Interleukins; D012333:RNA, Messenger; D009569:Nitric Oxide; D001120:Arginine