Surface hydrophobicity is increased in the ileum and proximal colon of cystic fibrosis mice

Bio-physical characteristics of gastrointestinal mucosa of celiac patients: comparison with control subjects and effect of gluten free diet-

Background

Intestinal mucosa is leaky in celiac disease (CD), and this alteration may involve changes in hydrophobicity of the mucus surface barrier in addition to alteration of the epithelial barrier. The aims of our study were i) to compare duodenal hydrophobicity as an index of mucus barrier integrity in CD patients studied before (n = 38) and during gluten- free diet (GFD, n = 68), and in control subjects (n = 90), and ii) to check for regional differences of hydrophobicity in the gastro-intestinal tract.

Methods

Hydrophobicity was assessed by measurement of contact angle (CA) (Rame Hart 100/10 goniometer) generated by a drop of water placed on intestinal mucosal biopsies.

Results

CA (mean ± SD) of distal duodenum was significantly lower in CD patients (56° ± 10°)) than in control subjects (69° ± 9°, p < 0.0001), and persisted abnormal in patients studied during gluten free diet (56° ± 9°; p < 0.005). CA was significantly higher (62° ± 9°) in histologically normal duodenal biopsies than in biopsies with Marsh 1-2 (58° ± 10°; p < 0.02) and Marsh 3 lesions (57° ± 10°; p < 0.02) in pooled results of all patients and controls studied. The order of hydrofobicity along the gastrointestinal tract in control subjects follows the pattern: gastric antrum > corpus > rectum > duodenum > oesophagus > ileum.

Conclusions

We conclude that the hydrophobicity of duodenal mucous layer is reduced in CD patients, and that the resulting decreased capacity to repel luminal contents may contribute to the increased intestinal permeability of CD. This alteration mirrors the severity of the mucosal lesions and is not completely reverted by gluten-free diet. Intestinal hydrophobicity exhibits regional differences in the human intestinal tract.

Restoration of mucociliary transport in the fluid-depleted trachea by surface-active instillates

Severe impairment of mucociliary transport (MCT) is a hallmark of cystic fibrosis (CF) lung disease. Recent studies demonstrate that pharmacologic inhibition of anion and liquid secretion in pig tracheas models the MCT defect in CF through depletion of the periciliary fluid component of airway surface liquid. In the present study, the effectiveness of various aqueous instillates on rehydration of the airway surface and restoration of MCT was assessed in this model. Excised porcine tracheas were mounted in a chamber that permitted simultaneous measurement of MCT and adventitial exposure of the airways to Krebs solution. When anion and liquid secretion were inhibited by treatment with bumetanide and dimethylamiloride, MCT was greatly reduced. Luminal instillation of aqueous solutions containing surface-active substances (1% Tween80 or calfactant) transiently restored MCT to high rates in nearly all tissues. Mucosal treatment with only Krebs solution or hypertonic saline restored MCT in only one half of the tracheas. We conclude that aqueous salt solutions alone can hydrate airway surfaces and restore MCT in some tissues, but surface-active substances may provide additional benefit in restoring MCT in this model of mucociliary stasis. We speculate that administration of surface-active substances, by aerosol or lavage, might help to restore MCT in the airways of patients with CF.