title: Fecal neutrophil gelatinase-associated lipocalin as a biomarker for inflammatory bowel disease.
abstract: OBJECTIVE
  Accurate, noninvasive biomarkers are needed to diagnose and monitor inflammatory bowel disease (IBD). Neutrophil gelatinase-associated lipocalin (NGAL), also known as lipocalin 2, is expressed in inflamed colonic epithelium and neutrophilic granulocytes. This study explores its properties as a biomarker in feces and plasma and, for the first time, compares fecal NGAL systematically with the existing fecal biomarker calprotectin.
  
  
  METHODS
  Neutrophil gelatinase-associated lipocalin was measured in feces from 73 patients with IBD, 21 patients with infectious enterocolitis, 21 patients with irritable bowel syndrome, and 23 healthy subjects using ELISA. The results were correlated to calprotectin, clinical score, endoscopic score, and high-sensitive C-reactive protein. Plasma from 119 patients with IBD and 28 healthy controls was analyzed for NGAL.
  
  
  RESULTS
  Fecal NGAL levels (median and interquartile range) were significantly elevated in active ulcerative colitis (UC) 6.05 (3.6-15.1) mg/kg and Crohn's disease (CD) 4.9 (1.5-7.7) mg/kg, compared with patients with inactive UC 1.3 (0.4-2.6) mg/kg, inactive CD 1.5 (0.5-1.7) mg/kg, irritable bowel syndrome 0.4 (0.2-0.6) mg/kg, and healthy controls (HC) 0.3 (0.1-0.4) mg/kg. Patients with infectious enterocolitis had significantly higher fecal-NGAL levels, 2.7 (1.4-5.6) mg/kg than HC. Sensitivity and specificity was 94.7% and 95.7%, respectively, for distinguishing between active IBD and HC. Stability of NGAL in stool was excellent for 7 days in room temperature. Plasma NGAL was significantly elevated in UC and CD compared with HC.
  
  
  CONCLUSIONS
  Fecal NGAL is a promising biomarker for IBD. As existing biomarkers are expressed mainly in granulocytes, NGAL's epithelial localization may give supplementary diagnostic information.
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.|Department of Gastroenterology, St. Olav's University Hospital, Trondheim, Norway.
authors.forename: Silje
authors.initials: S
authors.lastname: Thorsvik
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.|Department of Infectious Diseases, St. Olav's University Hospital, Trondheim, Norway.
authors.forename: Jan Kristian
authors.initials: JK
authors.lastname: Damås
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.|Department of Medical Microbiology, St. Olav's University Hospital, Trondheim, Norway.
authors.forename: Atle vB
authors.initials: AV
authors.lastname: Granlund
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Trude Helen
authors.initials: TH
authors.lastname: Flo
authors.affiliation: The Central Norway Regional Health Authority (RHA), Stjørdal, Norway.|Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Kåre
authors.initials: K
authors.lastname: Bergh
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.|Department of Gastroenterology, St. Olav's University Hospital, Trondheim, Norway.|Department of Medical Microbiology, St. Olav's University Hospital, Trondheim, Norway.
authors.forename: Ann Elisabet
authors.initials: AE
authors.lastname: Østvik
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.|Department of Gastroenterology, St. Olav's University Hospital, Trondheim, Norway.|Department of Medical Microbiology, St. Olav's University Hospital, Trondheim, Norway.
authors.forename: Arne Kristian
authors.initials: AK
authors.lastname: Sandvik
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis*; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis / Q000097:blood; D000071068:Lipocalin-2 / Q000032:analysis* / Q000097:blood; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D000071068:Lipocalin-2
keywords: IBD; NGAL/lipocalin 2; biomarkers