Histo- and morphometric changes in the large intestine mucosa in Crohn’s disease depending on the presence of fibrosis

Abstract

Background. One of the common complications of Crohn’s disease is the development of fibrotic changes in the wall of the large intestine, and, as a result, the risk of strictures. Morphometric study of the cellular composition of large intestine biopsy samples is one of the extended links of the diagnostic criteria for inflammatory bowel diseases, which make it possible to predict the development of the disease. Changes in the number of fibroblasts, as components of mesenchymal cells, can be considered a protective reaction to the intestinal tissue damage. The purpose of the study was to reveal changes in the histo- and morphometric parameters of the large intestine mucosa depending on the development of intestinal fibrosis in Crohn’s disease. Materials and methods. Colon biopsy samples from patients with Crohn’s disease (n=38) were examined histologically and morphometrically. According to morphological studies, patients were divided into two groups: with fibrotic changes in the intestinal wall (n=10) and without fibrosis (n=28). Results. Histologically, changes in the intestinal mucosa were observed in the form of altered integrity of the epithelium (78.3%), crypt architectonics (34.2%), mucosal edema (28.9%), crypt abscesses (47.3%). Fibrotic changes of the intestinal mucosa were found in 26.3% of patients. The inflammatory infiltrate contained neutrophils, eosinophils, lymphocytes, plasma cells, fibrocytes, and macrophages. At the same time, in the group of patients with Crohn’s disease and fibrosis, the number of representatives of the inflammatory infiltrate was higher than in the group of patients with Crohn’s disease without fibrosis. Patients with fibrotic changes in the intestinal wall were characterized by a higher density of inflammatory infiltrate the composition of which was dominated by macrophages and fibroblasts. Thickening of the intestinal mucosa was also observed in patients with fibrosis. The cause for such changes is the activation of the mechanism of fibrosis development against the background of inflammatory processes. Direct correlations were found between the fibrosis of the colon wall and the depth of crypts (r=0.35; p<0.05), the height of the crypt epithelium (r=0.41; p<0.05), cellular density of the infiltrate (r=0.45; p<0.05), the number of neutrophils (r=0.47; p<0.05), eosinophils (r=0.39; p<0.05), fibroblasts (r=0.57; p<0.05). Conclusions. In colon biopsy samples of patients with Crohn’s disease and intestinal fibrosis, a denser and increased level of inflammatory infiltrate is noted. The active development of the fibrotic process is directly related to the high level of fibroblasts in the infiltrate.