Angioarchitecture of the terminal vascular system in inflammatory bowel disease—A comparative corrosion‐anatomic study

The vascular origin of Crohn's disease (CD) and ulcerative colitis has been discussed but is poorly understood and investigated. A comparison of both diseases on the basis of the angioarchitecture had yet to be performed to investigate vascular morphology further and to evaluate its relevance for the etiology and differential diagnosis. The vascular system of 29 human colonic specimens of patients with CD (n=10), ulcerative colitis (n=11), and colon cancer (n=8), which were taken as controls, was perfused blood-free immediately after resection. Corrosion casts were obtained by injection of Mercox Cl and consecutive digestion with potassium hydroxide. Casts were then cut into sections, sputter coated with gold, and examined in a blinded fashion by scanning electron microscopy. Normal intestine showed a typical honeycomb appearance, the mucosal capillary network was smooth and regular, and the subepithelial vascular plexus was supplied by regularly arranged arterioles. In CD, a partially intact capillary net with alterations, dominant collecting veins, and a characteristic pattern of diameter changes with narrow segments in the capillary bed was seen. In ulcerative colitis a disruption of the colonic vascular architecture was found. The capillarization was rarefied and irregular lumps of subepithelial capillary structures were observed. The morphology of the terminal vascular bed in inflammatory bowel disease in contrast to normal controls is uniquely described. The technique of injecting fresh, human specimens was applied for the first time. The homogeneity of vascular changes within each entity seems to allow a differentiation between CD and ulcerative colitis.