title: Biomarkers of gut barrier failure in the ICU.
abstract: OBJECTIVE
  Gut barrier failure is associated with bacterial translocation, systemic inflammation, and is presumed to be associated with the development of multiple organ dysfunction syndrome. As the gut barrier function is carried out by a monolayer of enterocytes, a minimum requirement is the integrity of the enterocytes, and controlled paracellular permeability between adjacent enterocytes. Many factors can cause critically ill patients to lose gut barrier function by a mechanism of enterocyte damage; for example, small bowel ischemia or hypoxia, sepsis, systemic inflammatory response syndrome, or absence of enteral feeding.
  
  
  RESULTS
  Two enterocyte biomarkers may help the intensivist to identify enterocyte damage and dysfunction, namely plasma citrulline, a biomarker of functional enterocyte mass, and plasma or urinary intestinal fatty acid-binding protein, a marker of enterocyte damage. This review focuses on results obtained with these biomarkers in the context of critical care, in particular: prevalence of enterocyte biomarker abnormalities; mechanisms associated with enterocyte damage and dysfunction; link with systemic inflammation, bacterial translocation, and clinical intestinal dysfunction; prognostic value of enterocyte biomarkers. Lastly, we also review the limits of these biomarkers.
  
  
  CONCLUSIONS
  Enterocyte biomarkers may help the intensivist to identify patients presenting with intestinal damage, and who are at risk of bacterial translocation and systemic inflammatory response syndrome, as well as those with decreased enterocyte function, at risk of malabsorption. Enterocyte biomarkers should be interpreted with caution in the critically ill and should be interpreted within the overall clinical context of the patient.
authors.affiliation: aIntensive Care Unit, Besançon University Hospital bResearch Unit EA3920 and SFR FED 4234, University of Franche Comté, Besançon, France cDepartment of Epidemiology and Preventive Medicine, Australian and New Zealand Intensive Care Research Centre, Monash University, Clayton, Australia.
authors.forename: Gaël
authors.initials: G
authors.lastname: Piton
authors.forename: Gilles
authors.initials: G
authors.lastname: Capellier
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D003422:Critical Care; D016638:Critical Illness; D004750:Enteral Nutrition / Q000009:adverse effects; D020895:Enterocytes / Q000378:metabolism*; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D007362:Intensive Care Units; D007410:Intestinal Diseases / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D009102:Multiple Organ Failure / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D011379:Prognosis; D018805:Sepsis / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D015415:Biomarkers; C493404:FABP2 protein, human; D050556:Fatty Acid-Binding Proteins