CD3+CD4+LAP+Foxp3-regulatory cells of the colonic lamina propria limit disease extension in ulcerative colitis

Background and Aims: In ulcerative colitis (UC), inflammation begins in the rectum and can extend proximally throughout the entire colon. The extension of inflammation is an important determinant of disease course, and may be limited by the action of regulatory T cells (Tregs). In this cross-sectional study, we evaluated the relationship between UC extension and the proportions of CD3+CD4+Foxp3+ and CD3+CD4+LAP+Foxp3- Tregs in the colonic lamina propria (LP) of 79 UC patients and 29 controls. The role of these cells in UC extension was also investigated in the murine oxazolone-induced colitis model. Methods: Patients: Disease extension was classified according to the Montreal classification. Where possible, endoscopic biopsies of involved and uninvolved tissue were obtained from UC patients. Mouse model: Colitis was induced by intrarectal oxazolone administration. Lamina propria mononuclear cells were isolated from patient biopsies and mouse colon tissue using enzymatic method and the percentage of CD3+CD4+Foxp3+ and CD3+CD4+LAP+Foxp3-cells evaluated by immunofluorescence. Confocal microscopy was applied for the visualization and quantification of CD4+LAP+ cells on tissue histological sections. Results: In UC patients with distal colitis the proportion of LP CD3+CD4+Foxp3+ Tregs was significantly higher in inflamed tissue than uninvolved tissue. As opposite, the proportion of LP CD3+CD4+LAP+ Tregs was significantly higher in uninvolved tissue than involved tissue. Both LP CD3+CD4+Foxp3+ and LP CD3+CD4+LAP+ Tregs proportion in involved tissue was significantly higher than in controls irrespective of the extension of inflammation. In mice with oxazolone-induced distal colitis, treatment with LAP-depleting antibody was associated with the development of extensive colitis. Conclusions: Our findings suggest that CD3+CD4+LAP+Foxp3-Tregs limit the extension of inflammatory lesions in UC patients

Probiotic administration in patients with ileal pouch-anal anastomosis for ulcerative colitis is associated with expansion of mucosal regulatory cells.

BACKGROUND: Probiotics have anti-inflammatory effects in patients with inflammatory bowel disease and appear to regulate mucosal immune response through reductions in proinflammatory cytokines. The probiotic VSL#3 prevents pouchitis if started within a week of ileostomy closure and maintains remission following antibacterial treatment in patients with refractory or recurrent pouchitis. However, the efficacy of probiotics and their effects on regulatory cells if started at a greater time after surgery in patients undergoing ileal pouch anal anastomosis (IPAA) for ulcerative colitis are unknown. METHODS: We conducted an open-label study in which 31 patients at different periods from surgery without signs and symptoms of pouchitis were randomized to 2 sachets of VSL#3 once daily or no treatment for 12 months. Pouchitis disease activity index (PDAI) was evaluated at baseline and after 3, 6, and 12 months. The percentage of CD4+ T lymphocytes expressing CD25 and the inactive form of transforming growth factor-beta [latency-associated peptide (LAP)] were evaluated at baseline and after 3 and 6 months in peripheral-blood mononuclear cells and mucosal biopsies. Variation in tissue interleukin-1beta and Foxp3 mRNA expression was also evaluated. RESULTS: During the study period, VSL#3-treated patients showed a significant reduction in PDAI score and a significant increase in the percentage of mucosal CD4+CD25(high) and CD4+ LAP-positive cells compared with baseline values. Tissue samples at different points showed a significant reduction in IL-1beta mRNA expression, and a significant increase in Foxp3 mRNA expression. CONCLUSIONS: We conclude that VSL#3 administration in patients with IPAA modulates the PDAI and expands the number of mucosal regulatory T cells

IL-13 mRNA tissue content identifies two subsets of adult ulcerative colitis patients with different clinical and mucosa-associated microbiota profiles

BACKGROUND AND AIM: A personalized approach to therapy has great promise to improve disease outcomes. To this end, the identification of different subsets of patients according with the prevalent pathogenic process might guide in the choice of therapeutic strategy. We hypothesize that UC patients might be stratified according to distinctive cytokine profiles and/or to a specific mucosa-associated microbiota. METHODS: In a cohort of clinically and endoscopic active UC patients and controls, we analyzed by qPCR the mucosal cytokine mRNA content and the mucosa-associated microbiota composition assessed by the 16SrRNA gene sequencing. RESULTS: We demonstrate, by means of data-driven approach, the existence of a specific UC patient subgroup characterized by elevated IL-13mRNA tissue content separated by patients with low IL-13 mRNA tissue content. The two subsets differ in clinical-pathological characteristics. High IL-13mRNA patients are younger at diagnosis and show higher prevalence of extensive colitis than low IL-13mRNA ones. They also show a more frequent use of steroid/immunosuppressant/anti-TNFα therapy during a one-year follow-up. The two subgroups show a differential enrichment of mucosa associated microbiota genera with prevalence of Prevotella in patients with high IL-13mRNA tissue content and Sutterella and Acidaminococcus in patients with low IL-13mRNA tissue content. CONCLUSION: Assessment of mucosal IL-13mRNA might help in the identification of the patients' subgroup that might benefit from a therapeutic approach modulating IL-13

The Mutyh Base Excision Repair Gene Influences the Inflammatory Response in a Mouse Model of Ulcerative Colitis

BACKGROUND: The Mutyh DNA glycosylase is involved in the repair of oxidized DNA bases. Mutations in the human MUTYH gene are responsible for colorectal cancer in familial adenomatous polyposis. Since defective DNA repair genes might contribute to the increased cancer risk associated with inflammatory bowel diseases, we compared the inflammatory response of wild-type and Mutyh(-/-) mice to oxidative stress. METHODOLOGY/PRINCIPAL FINDINGS: The severity of colitis, changes in expression of genes involved in DNA repair and inflammation, DNA 8-oxoguanine levels and microsatellite instability were analysed in colon of mice treated with dextran sulfate sodium (DSS). The Mutyh(-/-) phenotype was associated with a significant accumulation of 8-oxoguanine in colon DNA of treated mice. A single DSS cycle induced severe acute ulcerative colitis in wild-type mice, whereas lesions were modest in Mutyh(-/-) mice, and this was associated with moderate variations in the expression of several cytokines. Eight DSS cycles caused chronic colitis in both wild-type and Mutyh(-/-) mice. Lymphoid hyperplasia and a significant reduction in Foxp3(+) regulatory T cells were observed only in Mutyh(-/-) mice. CONCLUSIONS: The findings indicate that, in this model of ulcerative colitis, Mutyh plays a major role in maintaining intestinal integrity by affecting the inflammatory response