Impaired gastric paracellular barrier in FD patients: in vivo evaluation by confocal endomicroscopy

OBJECTIVES:The pathophysiology of functional dyspepsia (FD) is still poorly understood. Increased paracellular permeability is a potential cause of barrier loss during low-grade inflammation. Our aim was to evaluate whether gastric barrier loss in FD patients can be detected in vivo by confocal endomicroscopy and their characteristic. METHODS:Confocal endomicroscopy was performed in FD and control patients using intravenous fluorescein to determine the local barrier dysfunction. A grading system based on appearances at endomicroscopy was devised. Gastric biopsy specimens were obtained from 30 patients with FD fulfilling the Rome III criteria and 10 healthy volunteers. Biopsy samples were taken for histopathology and permeability test by lanthanum tracer. The distribution of fluorescein signals were assessed by immunohistochemistry. RESULTS: Confocal endomicroscopy in humans detected local barrier defects as plumes of fluorescein effluxing through the epithelium. The results of endomicroscopyic assessment correlated well with the electron microscopy findings. Patients with FD displayed increased paracellular passage compared with healthy controls. There was no significant difference regarding demographic and H pylori infection in EPS and PDS patients. Compared to healthy subjects and PDS patients, EPS patients significantly increased permeability in gastic epithelium(p less than 0.01 and 0.05). CONCLUSIONS: Impaired paracellular barrier may be a potential a pathophysiological mechanism in FD. These findings might pave the way both to identify novel biomarkers as well as new therapeutic targets in FD.