Morphological and Immunohistochemical Features of the Pancreatic Duct System in Patients with Chronic Pancreatitis

Abstract

Background: The duct cells make up to 30% of the human pancreas. One of the first signs of chronic pancreatitis is the abnormal increase in the number of duct brunches. The pancreatic ductal changes, periductal, inter- and intralobular fibrosis etc. are not the causes of chronic pancreatitis, but its consequences. The aim of the present study was to determine morphological and immunohistochemical features of the pancreatic duct system in patients with chronic pancreatitis, who underwent surgery for chronic pancreatitis. Materials and methods: An immunohistochemical study of the surgical material of 40 patients with complicated chronic pancreatitis was carried out using antibodies to α-SMA, desmin, fibronectin and type I collagen. Results: A characteristic morphological picture of the chronic pancreatitis in development is a combination of fibrosis with deformation of the duct system due to periductal fibrosis with the expansion of interlobular fibrosis, thickening of intralobular connective tissue strands, as well as considerable crimp and widening of the ducts with retention cysts. Significant structural reorganization of the pancreatic duct system in patients with chronic pancreatitis was observed in 87.5% of cases, in 17.5% of cases the picture was supplemented by phenomena of acinar-ductal metaplasia with the transformation of acinar cells into ductal cells and the formation of small ductal-like structures, the so-called “tubular complexes”. In 7.5% of the cases in the main pancreatic duct, foci of atrophy of the epithelium were identified, which alternated with foci of papillary intraepithelial epithelial hyperplasia (PanIN). The development of pancreatic fibrosis in chronic pancreatitis is facilitated by the accumulation of α-SMA+ activated pancreatic stellate cells synthesizing an excess of components of the extra-cellular matrix, in particular type I collagen. The mean area of type I collagen and the intensity of its expression were significantly lower with reduced α-SMA expression (p <0.05), and significantly higher in cases of pronounced fibronectin expression (p <0.05).