title: Protocol for a prospective, controlled, observational study to evaluate the influence of hypoxia on healthy volunteers and patients with inflammatory bowel disease: the Altitude IBD Study.
abstract: Inflammatory bowel disease (IBD) is a chronic intestinal disorder, often leading to an impaired quality of life in affected patients. The importance of environmental factors in the pathogenesis of IBD, including their disease-modifying potential, is increasingly recognised. Hypoxia seems to be an important driver of inflammation, as has been reported by our group and others. The aim of the study is to evaluate if hypoxia can alter disease activity of IBD measured by Harvey-Bradshaw Activity Index in Crohn's disease (increase to ≥5 points) and the partial Mayo Score for ulcerative colitis (increase to ≥2 points). To test the effects of hypoxia under standardised conditions, we designed a prospective and controlled investigation in healthy controls and patients with IBD in stable remission.
  
  
  
  This is a prospective, controlled and observational study. Participants undergo a 3-hour exposure to hypoxic conditions simulating an altitude of 4000 metres above sea level (m.a.s.l.) in a hypobaric pressure chamber. Clinical parameters, as well as blood and stool samples and biopsies from the sigmoid colon are collected at subsequent time points.
  
  
  
  The study protocol was approved by the Ethics Committee of the Kanton Zurich (reference KEK-ZH-number 2013-0284). The results will be published in a peer-reviewed journal and shared with the worldwide medical community.
  
  
  
  NCT02849821; Pre-results.
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.|Division of Gastroenterology, Triemli Hospital, Zurich, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Vavricka
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Ruiz
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Scharl
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Luc
authors.initials: L
authors.lastname: Biedermann
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Scharl
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.|Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
authors.forename: Cheryl
authors.initials: C
authors.lastname: de Vallière
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.|Institute of Physiology, University of Zurich, Zurich, Switzerland.
authors.forename: Carsten
authors.initials: C
authors.lastname: Lundby
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.|Institute of Physiology, University of Zurich, Zurich, Switzerland.
authors.forename: Roland H
authors.initials: RH
authors.lastname: Wenger
authors.affiliation: Institute of Biostatistics, University of Zurich, Zurich, Switzerland.
authors.forename: Leonhard
authors.initials: L
authors.lastname: Held
authors.affiliation: Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Merz
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.|Vetsuisse Faculty, Institute of Veterinary Physiology, Zurich, Switzerland.|Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru.
authors.forename: Max
authors.initials: M
authors.lastname: Gassmann
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.|Vetsuisse Faculty, Institute of Veterinary Physiology, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lutz
authors.affiliation: Swiss Aeromedical Center, Dubendorf, Switzerland.
authors.forename: Andres
authors.initials: A
authors.lastname: Kunz
authors.affiliation: Swiss Aeromedical Center, Dubendorf, Switzerland.
authors.forename: Denis
authors.initials: D
authors.lastname: Bron
authors.affiliation: Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland.
authors.forename: Adriano
authors.initials: A
authors.lastname: Fontana
authors.affiliation: Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland.
authors.forename: Laura
authors.initials: L
authors.lastname: Strauss
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.|Institute of Pathology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Achim
authors.initials: A
authors.lastname: Weber
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Fried
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.|Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rogler
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Jonas
authors.identifier: 0000-0002-0885-0064
authors.initials: J
authors.lastname: Zeitz
mesh_terms: D000293:Adolescent; D000328:Adult; D000531:Altitude; D000809:Angiotensins / Q000097:blood / Q000652:urine; D001706:Biopsy; D001794:Blood Pressure; D003093:Colitis, Ulcerative / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D012809:Colon, Sigmoid / Q000473:pathology; D003424:Crohn Disease / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D016207:Cytokines / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000150:complications / Q000503:physiopathology*; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics / Q000378:metabolism; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis; D008875:Middle Aged; D009929:Organ Size; D011446:Prospective Studies; D012107:Research Design; D012720:Severity of Illness Index; D012812:Sigmoidoscopy; D001743:Urinary Bladder / Q000033:anatomy & histology; D014667:Vasopressins / Q000097:blood / Q000652:urine; D055815:Young Adult
chemical_list: D000809:Angiotensins; D016207:Cytokines; D051793:Hypoxia-Inducible Factor 1; D039841:Leukocyte L1 Antigen Complex; D014667:Vasopressins
keywords: Crohn's disease; Hypoxia; Ulcerative colitis