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Purpose: There is increasing evidence that a defect of the gastrointestinal mucosal barrier is important for the development of inflammatory bowel diseases (IBD). The hydrophobicity of the colonic mucosal surface is a measure of its resistance to luminal antigens, e.g. of bacterial origin. Therefore, the purpose of this study was to determine this parameter in patients suffering from IBD., Methods: Nineteen patients with ulcerative colitis (UC), ten patients with Crohn's disease (CD) and 20 controls were examined. All underwent colonic surgery at the University Hospital Heidelberg. Clinical disease activity was determined. From every subject, colonic tissue specimens were obtained, and hydrophobicity of the mucosal surface was determined with a goniometer by multiple plateau contact angle measurements. Histological evaluation of disease activity was performed in directly adjacent tissue specimens., Results: Hydrophobicity of the colonic mucosal surface, expressed as plateau contact angles, was significantly reduced in patients with UC (mean ± SEM, 47.8° ± 3.4°) compared to those with CD (72.0° ± 5.2°) and controls (72.5° ± 5.6°; over-all P = 0.0004; UC versus controls, P < 0.001; UC versus CD, P < 0.05; CD versus controls, P > 0.05). Between mucosal hydrophobicity and clinical disease activity, as well as mucosal hydrophobicity and histological disease activity, no significant correlation was found., Conclusions: The results suggest a defective physicochemical barrier as an essential factor in the pathogenesis of UC, but not CD. The fact that no correlation was found between mucosal hydrophobicity and disease activity may indicate that the loss of mucosal hydrophobicity in UC is not exclusively a secondary effect due to inflammation.

Background and Aims: The pathogenesis of pouchitis, major complication after restorative proctocolectomy, and ileal J pouch-anal anastomosis (IPAA) in patients with ulcerative colitis (UC) is still unclear. Changes in intraluminal bacterial colonization and correlated changes of pouch mucosa are thought to play an important role. Toll-like receptors (TLRs) as part of the innate immune system are capable of recognizing bacterial antigens. Their activation can lead to secretion of proinflammatory mediators. In this study, TLR2, 3, 4, and 5 expression profiles in the pouch mucosa of patients with UC and IPAA were analyzed and correlated with pouchitis., Materials and Methods: Clinical symptoms, endoscopy, and histology were assessed in 35 patients using the Heidelberg Pouchitis Activity Score to classify patients as either having pouchitis or not. TLR mRNA expression in normal ileal mucosa and pouch mucosa was investigated by performing semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). The results of RT-PCR were associated with the pouchitis score., Results: In the analysis of all patients, TLR3 expression was decreased significantly whereas TLR5 expression was increased significantly in pouch mucosa compared to normal ileal mucosa (p-values 0.0076 and 0.016, respectively). A more detailed analysis upon dividing the patients into patients with and without pouchitis showed decreased TLR3 expression in the pouch mucosa only of patients without pouchitis (p-value=0.0067). TLR5 expression was increased in the pouch mucosa only of patients with pouchitis (p-value=0.023). No differences in TLR2 and 4 expression were found in either group., Conclusion: Differential expression of TLR3 and 5 suggests bacterial involvement in the pathogenesis of pouchitis in patients with UC.