Immunohistochemical Analysis of ZO-1 in the Duodenal Mucosa of Patients with Untreated and Treated Celiac Disease

Abstract

Background/Aim: ZO-1 is a good marker for tight junction integrity which may be damaged in many intestinal diseases. ZO-1 can also accumulate in the cellular nucleus in addition to sites of cell-cell contact, suggesting a potential role in cellular proliferation and differentiation. We evaluated the expression and distribution of ZO-1 in patients with celiac disease before and after a gluten-free diet. Methods: The ZO-1 expression was evaluated semiquantitatively by means of immunohistochemical analysis in duodenal bioptic specimens of 10 consecutive patients with celiac disease before and after a gluten-free diet and in 10 controls. Furthermore, the nuclear staining was analyzed quantitatively, evaluating 3,000 cells for each count, and it was expressed as a percentage of labeled nuclei over the total of analyzed cells. Results: The intestinal mucosa of untreated celiac disease patients shows a globally lower ZO-1 labeling than that of controls. The expression of ZO-1 in the treated celiac mucosa did not differ significantly from normal intestinal mucosa of healthy subjects. At the crypt level of untreated celiac mucosa, a low intensity of nuclear labeling (1.75 ± 0.32%) was found, while in both treated celiac disease patients and in normal subjects we observed a statistically significant higher percentage of strongly labeled nuclei (53.72 ± 6.30% and 56.79 ± 5.45%, respectively; p = 0.0002). Conclusions: Our data show a global underexpression of ZO-1 in the duodenal mucosa of active celiac disease patients. Gluten withdrawal allows a normalization of the ZO-1 expression in treated celiac disease patients. Furthermore, the particular pattern of ZO-1 resembles the cellular distribution in undifferentiated cells and may be the result of immaturity of the enterocytes in untreated celiac sprue.