Probiotic Mixture VSL#3 Alleviates Dextran Sulfate Sodium-induced Colitis in Mice by Downregulating T Follicular Helper Cells.

Clinical trials have shown beneficial effects of probiotics on inflammatory bowel diseases (IBD), although the exact mechanism remains unknown. VSL#3, a mixture of 8 probiotic bacteria, has been confirmed to have adjunctive therapeutic effects on colitis. T follicular helper (Tfh) cells, a new separate subset of CD4+ T helper cells, have been proved to play a vital role in autoimmunity. The present study aimed to identify the beneficial effect of the probiotic mixture VSL#3 on the mouse model of colitis by regulating Tfh cells. Dextran sulfate sodium (DSS) was used to induce chronic colitis in C57BL/6 mice. VSL#3 (3×109 live bacteria) was given to C57BL/6 mice every other day for 60 days by gavage. The disease activity index (DAI), histological activity index (HAI), colon length and myeloperoxidase (MPO) activity were detected. Immunofluorescence was used to visualize the location of Tfh cells. Immunoglobulins, Tfh cells and plasma cells were quantified by enzyme-linked immunosorbent assay (ELISA), flow cytometry, real-time PCR or Western blotting. The results showed that after DSS treatment, the humoral immunity was disordered in C57BL/6 mice, with increased IgM, IgG and IgA levels in colonic mucus and increased Tfh cells in mesenteric lymph nodes (MLN). VSL#3 treatment showed anti-inflammatory effects as evidenced by reduced DAI score, HAI score and MPO activity. IgM, IgG and IgA levels were significantly reduced in colon mucus, and the number of Tfh cells was markedly decreased in MLN after VSL#3 treatment. It was concluded that VSL#3 alleviates DSS-induced colitis by downregulating Tfh cells, and Tfh cells may become a potential therapeutic target for IBD.

Risk factors for colorectal neoplasia in patients with underlying inflammatory bowel disease: a multicenter study.

BACKGROUND: This study sought to evaluate the risk factors for the development of colitis-associated neoplasia (CAN) in Chinese patients with inflammatory bowel disease (IBD). METHODS: IBD patients who developed CAN between 1999 and 2016 were identified from eight medical centers. In addition to initial pathology evaluation, a CAN diagnosis was confirmed by two expert pathologists. Patients with CAN (n = 29) were compared with non-CAN controls (n = 87). Matching was performed for gender and IBD type with a ratio of three controls to one subject. RESULTS: Of the 29 patients with CAN, 8 (27.6%) had colorectal cancer (CRC), 20 (69.0%) had a final diagnosis of low-grade dysplasia and 1 (3.4%) had high-grade dysplasia. Multivariate analysis revealed that an older age at the time of IBD diagnosis and a longer IBD duration were independent risk factors for the development of CAN, with odds ratios of 1.09 [95% confidence interval (CI): 1.04-1.14, P < 0.001] and 1.14 (95% CI: 1.03-1.27, P = 0.013), respectively. Comparison between IBD patients with CRC and those with dysplasia indicated that the former were older at the time of IBD diagnosis (P = 0.012) and had longer IBD durations (P = 0.019). CONCLUSIONS: Older age at the time of IBD diagnosis and longer IBD duration were found to be associated with the development of CAN in IBD patients.

Expression and implication of toll-like receptors TLR2, TLR4 and TLR9 in colonic mucosa of patients with ulcerative colitis.

Toll-like receptors (TLRs) family may play important roles in inflammatory bowel disease. This study examined the expression of TLR2, TLR4 and TLR9 in the colonic tissues of patients with ulcerative colitis (UC) and explored their roles in the pathogenesis of UC. Colonic biopsies were taken from the colon of 30 patients with mild or moderate UC (at active phase) and 10 healthy controls during colonoscopy. TLR2, TLR4 and TLR9 protein expression levels were immunohistochemically detected. The mRNA expression levels of TLR2, TLR4 and TLR9 were assessed by reverse transcription polymerase chain reaction (RT-PCR). The disease activity index (DAI), colonoscopic and histologic grades and fecal microbial flora were determined. Histological examination showed that the intestinal mucous membrane of UC patients underwent acute inflammation changes. Immunohistochemistry exhibited that the expression levels of TLR2, TLR4 and TLR9 in colon epithelia and inflammatory cells were higher in UC patients than in control group (P<0.01). The mRNA expression levels of TLR2, TLR4 and TLR9 were increased in UC patients but were not detected in the normal controls. Expression levels of TLR2, TLR4 and TLR9 were positively correlated, and bore close correlation with DAI, colonoscopic and histologic grades and fecal microbial flora. An important mechanism of UC might be that abnormal activation of mucosal immunity by intestinal dysbacteriosis caused dysregulation of TLRS that mediates innate immunity.

[The relationship between major histocompatibility complex class I chain-related antigens A (MICA)-129 gene polymorphism, soluble MICA level and ulcerative colitis].

OBJECTIVE: To investigate the association of the major histocompatibility complex class I chain-related antigens A (MICA)-129 gene polymorphism and soluble MICA (sMICA) levels with ulcerative colitis (UC) in Hubei Han nationality. METHODS: The genetic polymorphism of MICA-129 was examined using a polymerase chain reaction-sequence based test (PCR-SBT) in 256 UC patients and 460 healthy controls. From the above subjects, 80 patients and 90 healthy individuals were randomly selected for determining serum sMICA concentrations by ELISA. RESULTS: The frequencies of variant allele (G) and genotype (GG) in MICA-129 gene were significantly higher in the UC patients than in the controls (76.8% vs 72.2%, P = 0.060; 55.9% vs 46.3%, P = 0.016). Serum sMICA levels were significantly elevated in the patients compared to the controls [(576.47 ± 279.02) ng/L vs (182.17 ± 73.11) ng/L, P < 0.001]. In addition, the sMICA levels were higher in the patients carrying MICA-129 GG genotypes than in those carrying (GA + AA) genotypes [(638.87 ± 347.15) ng/L vs (507.51 ± 152.87) ng/L, P = 0.035]. CONCLUSIONS: The genetic polymorphism of MICA-129 and sMICA levels are correlated with the UC patients in Hubei Han nationality. Our findings demonstrate that MICA-129 gene may contribute to the pathogenesis of UC.

[CTLA-4 gene polymorphism regulates CTLA-4 mRNA stability and protein level in patients with ulcerative colitis].

OBJECTIVE: To investigate the effect of (AT)n repeat polymorphism of the 3'untranslated region in cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) gene on CTLA-4 mRNA stability and full length (flCTLA-4) and soluble CTLA4 (sCTLA-4) expression in ulcerative colitis (UC). METHODS: flCTLA-4 mRNA in colonic biopsies and sCTLA-4 mRNA stability in peripheral blood mononuclear cells of UC patients were measured by quantitative PCR and half-life, respectively. The protein expression of flCTLA-4 in colonic biopsies and sCTLA-4 in sera of UC patients were determined by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The polymorphism of CTLA-4 (AT)n repeats in 300 UC and 700 age and sex matched healthy controls was genotyped by fluorescent PCR. RESULTS: Among the UC patients, sCTLA-4 mRNA expression levels were decreased in active disease compared to non-active disease (P= 0.004). Carriers of the longer alleles of the (AT)n repeats expressed lower levels of flCTLA-4 and sCTLA-4 mRNA and sCTLA-4 protein than those of the shorter alleles in UC (all P< 0.01), and mRNA with long (AT)n repeat alleles has shorter half-life than mRNA with short alleles and, hence, are unstable. The frequency of long allele carriers of CTLA-4 (AT)n repeats was significantly higher in UC patients than in the healthy controls (22.0% vs. 6.3%, P< 0.01, OR= 4.21, 95% CI: 2.79-6.33), and associated with extensive colitis (P= 0.008). CONCLUSION: CTLA-4 gene expression levels were associated with (AT)n repeat polymorphisms in UC patients. The expression of CTLA-4 mRNA and protein were decreased in carriers of the longer alleles of the (AT)n repeats of CTLA-4 gene. This study suggests that CTLA-4 plays an important role in genetic risk and pathophysiology for UC in central China.

[Phenotypic analysis of Th cells in colon and peripheral blood in patients with irritable bowel syndrome].

UNLABELLED: OBJECTIVE; To analyze the change of Th1/Th2/Th17 in colonic mucosa and peripheral blood in diarrhea-predominant IBS (D-IBS) to uncover the underlying mechanism for the activation of mucosal immune system. METHODS: Colonic biopsy specimens and peripheral blood were obtained from patients with D-IBS (n = 27) and controls (n = 16). Two different groups were classified on the basis of histological assessment of biopsy specimens from D-IBS patients. One group (14 of 27) had normal conventional histology (IBS), while another group (13 of 27) had nonspecific microscopic inflammation (IBS-A). Flow cytometric detection of intracellular IFN-gamma/IL-4/IL-17 cytokine production was employed to investigate Th1, Th2 and Th17 cells in colonic lamina propria and peripheral blood. Western blot was used to determine the expressions of IL-12, IL-4 and IL-17 in colonic mucosa. The levels of IL-12, IL-4 and IL-17 in peripheral blood were detected by ELISA. RESULTS: In colonic mucosa, the proportion of Th17 increased in IBS-A group as compared with controls [3.60 (4.05) vs 1.25 (3.70), P = 0.045], but not in IBS group. No difference could be observed in the frequencies of Th1 and Th2 in colonic mucosa and peripheral blood. The levels of IL-12, IL4 and IL-17 in IBS and IBS-A showed no difference in either colonic mucosa or peripheral blood. CONCLUSION: Subgroup of D-IBS showed abnormal conventional histology, implicating the activation of mucosal immune system in pathogenesis. The shift of Th1/Th2/Th17 balance in colonic mucosa showed the enhanced Th17 activity.