title: Serum leucine-rich alpha-2 glycoprotein is a disease activity biomarker in ulcerative colitis.
abstract: BACKGROUND
  Reliable biomarkers for monitoring disease activity have not been clinically established in ulcerative colitis (UC). This study aimed to investigate whether levels of serum leucine-rich alpha-2 glycoprotein (LRG), identified recently as a potential disease activity marker in Crohn's disease and rheumatoid arthritis, correlate with disease activity in UC.
  
  
  METHODS
  Serum LRG concentrations were determined by enzyme-linked immunosorbent assay (ELISA) in patients with UC and healthy controls (HC) and were evaluated for correlation with disease activity. Expression of LRG in inflamed colonic tissues from patients with UC was analyzed by western blotting and immunohistochemistry. Interleukin (IL)-6-independent induction of LRG was investigated using IL-6-deficient mice by lipopolysaccharide (LPS)-mediated acute inflammation and dextran sodium sulfate (DSS)-induced colitis.
  
  
  RESULTS
  Serum LRG concentrations were significantly elevated in active UC patients compared with patients in remission (P < 0.0001) and HC (P < 0.0001) and were correlated with disease activity in UC better than C-reactive protein (CRP). Expression of LRG was increased in inflamed colonic tissues in UC. Tumor necrosis factor alpha (TNF-α), IL-6, and IL-22, serum levels of which were elevated in patients with active UC, could induce LRG expression in COLO205 cells. Serum LRG levels were increased in IL-6-deficient mice with LPS-mediated acute inflammation and DSS-induced colitis.
  
  
  CONCLUSIONS
  Serum LRG concentrations correlate well with disease activity in UC. LRG induction is robust in inflamed colons and is likely to involve an IL-6-independent pathway. Serum LRG is thus a novel serum biomarker for monitoring disease activity in UC and is a promising surrogate for CRP.
authors.affiliation: Laboratory for Immune Signal, National Institute of Biomedical Innovation, Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Serada
authors.forename: Minoru
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Terabe
authors.forename: Hideki
authors.initials: H
authors.lastname: Iijima
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Shinzaki
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsuzaki
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Ohkawara
authors.forename: Riichiro
authors.initials: R
authors.lastname: Nezu
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nakajima
authors.forename: Taku
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Scott Eric
authors.initials: SE
authors.lastname: Plevy
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Takehara
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Naka
mesh_terms: D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000097:blood*; D015153:Blotting, Western; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000097:blood / Q000139:chemically induced / Q000175:diagnosis*; D016207:Cytokines / Q000097:blood / Q000235:genetics; D018450:Disease Progression; D005260:Female; D006023:Glycoproteins / Q000097:blood* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007249:Inflammation / Q000097:blood / Q000139:chemically induced / Q000473:pathology*; D015850:Interleukin-6 / Q000502:physiology*; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012074:Remission Induction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D016207:Cytokines; D006023:Glycoproteins; D015850:Interleukin-6; C015246:LRG1 protein, human; C530631:LRG1 protein, mouse; D008070:Lipopolysaccharides; D012333:RNA, Messenger