Features of the claudin 1 and 7 expression in the mucous membrane of the large intestine in symptomatic uncomplicated diverticular disease and acute uncomplicated diverticulitis

Background. Diverticular disease is one of the most common gastrointestinal pathologies, which mainly damages the large intestine and is manifested morphologically by the formation of sac-like protrusions (diverticula) of the intestinal wall. Today, the etiopathogenesis of diverticular disease remains debatable and needs to be fully understood. Changes in the claudin expression in the colonic mucosa and, accordingly, their structural instability may play a certain role in the development of both diverticular disease and its complications. The study aimed to determine the features of claudin 1 and 7 expression in the colonic mucosa of patients with symptomatic uncomplicated diverticular disease (SUDD) and acute uncomplicated diverticulitis (AUD). Materials and methods. Fragments of the colonic mucosa of 12 individuals without gastrointestinal pathology (group 1), biopsies of the colo­nic mucosa from the diverticular orifice of 34 patients with SUDD (group 2) and 26 patients with AUD (group 3) were analyzed. An immunohistochemical study used rabbit polyclonal antibodies to claudins 1 and 7. The PAST program was applied to process digi­tal indicators. The average indicators in groups were compared using the Student’s t-test and Mann-Whitney U-test. Results. A comprehensive morphological study revealed a decrease in the expression of claudins 1 and 7 in the colonic mucosa of patients with SUDD and AUD, more pronounced in those with AUD. In the large intestine mucosa of people without gastrointestinal pathology and patients with SUDD and AUD, firstly, the content of claudins 1 and 7 was higher in the surface epithelium compared to the epithelium of the intestinal glands, secondly, the content of claudin 1 predominated over claudin 7 content. Conclusions. The detected changes in claudin 1 and 7 expression in the colonic mucosa biopsies may underlie the development of diverticular disease and its complications.