In vivo and in vitro permeability in coeliac disease

Background: An increased permeability to sugars is found in the intestine o f untreated patients with coeliac disease after oral ingestion. Aim: To test whether in vitro permeability resembles in vivo permeability t ests and whether an in vitro gliadin gluten challenge could be performed by an in vitro permeability test. Methods: We measured in vivo (urinary excretion after sucrose-lactulose-man nitol ingestion) and in vitro permeability (by mini-Ussing chambers) in 25 healthy controls, 12 relatives of coeliac disease patients, 19 treated, eig ht partly treated and 16 untreated patients with coeliac disease. Results: In vivo sugar permeability was increased in nearly all coeliac pat ients. Additionally, in vitro permeability to lactulose (P = 0.0007), manni tol (P = 0.004) and sucrose (P = 0.042) was higher in untreated patients wi th coeliac disease. It correlated with in vivo permeability (sucrose tau = 0.61, P = 0.006; lactulose tau = 0.41, P < 0.0001; mannitol <tau> = 0.56, P = 0.62) and was dependent on mucosal damage. An in vitro gliadin challenge over 24 h could not significantly change in vitro permeability in treated patients with coeliac disease. Conclusions: An in vitro permeability test capable of measuring elevated pe rmeability in coeliac mucosa was described, but this test cannot replace or al gluten challenge by in vitro gliadin incubation.