COMPARISON OF 4 MARKERS OF INTESTINAL PERMEABILITY IN CONTROL SUBJECTS AND PATIENTS WITH CELIAC-DISEASE

Background: Controversy surrounds the issue of intestinal permeability in patients with coeliac disease, polyethylene glycol 400 indicating reduced and di-/mono-saccharide urine excretion ratios and Cr-51-label ed ethylenediaminetetraacetic acid (EDTA) indicating increased permeab ility. Methods: We assessed the suitability of polyethylene glycol 400 , L-rhamnose, lactulose, and Cr-51-EDTA as markers of intestinal perme ability by assessing urine excretions after simultaneous intravenous i nstillation of these markers and after oral administration in normals and patients with coeliac disease. Results: After intravenous administ ration the 24-h urine excretion of polyethylene glycol 400, L-rhamnose , lactulose, and Cr-51-EDTA was 40%, 72%, 93%, and 97%, respectively. There was no significant difference between controls and patients with coeliac disease. Oral administration of the markers in an iso- and hy per-osmolar test solution demonstrates reduced permeation due to an os motic retention effect of lactulose. In contrast, hyperosmolar glycero l increases permeation of all markers except L-rhamnose. Timing of uri nes and altering osmolarity is important for the behaviour of individu al markers but does not enhance the discrimination between controls an d patients when the differential urine excretion of lactulose/L-rhamno se is used. The sensitivity of the urine excretion ratio of lactulose/ L-rhamnose was comparable to that of Cr-51-EDTA used by itself. Wherea s lactulose/L-rhamnose and Cr-51-EDTA showed increased intestinal perm eability in coeliac disease, the permeation of polyethylene glycol was reduced. Permeation of the markers did not correlate significantly wi th jejunal histology. Conclusions: Correlations of marker permeation r ates with test dose osmolarity in controls and patients with coeliac d isease shows a variable lack of conformity, suggesting that the marker s may permeate the intestine by different routes, which are affected t o a different extent in coeliac disease.