Strukturelle Veränderungen der apikalen Zellmembran in Enterozyten bei Morbus Crohn und Colitis ulcerosa

Abstract

Introduction: Structural alterations of the apical cell membrane and the microvillus cytoskeleton may contribute to increased transcellular permeability in Crohn’s disease (CD) and ulcerative colitis (UC). The aim of this study was to investigate the distribution of sucrase- isomaltase (S-I), a disaccharidase of the apical brush border, and villin (V), a protein of the microvillus cytoskeleton, in normal enterocytes (NE) and enterocytes with rapid antigen uptake into the cytosol (RACE) from healthy controls (HC) or patients with CD or UC. Methods: Labeling densities (LD) of S-I- and V-binding antibodies were determined by immunoelectron microscopy in CD [ileum (il), n=5] and UC [colon (co), n = 5] and was compared to HC (il, n = 5; co,n = 5). Wilcoxon U-test was used for statistical analysis with p < 0.05 considered to be significant. Results: LD of S-I was significantly decreased in NE of CD compared to HC-il (p < 0.01) and in RACE of CD compared to the corresponding NE (p < 0.01). In UC, LD of S-I was significantly higher in NE compared to both HC-co (p < 0.01) and RACE (p < 0.01). In CD and UC, LD for V was significantly decreased in NE compared to HC-il and HC-co (p < 0.05) and in RACE compared to NE (p < 0.01). Conclusion: These results support the thesis of a structural alteration of intestinal enterocytes in CD and UC. Altered epithelia may increase (transcellular) intestinal permeability, which may result in an increased uptake of luminal antigens in CD and UC.