Prophylactic Administration of Magnesium Oxide Prevents Dextran Sulfate Sodium-Induced Colonic Injury in Mice.

We previously demonstrated that per os administration and ad libitum ingestion of a magnesium chloride (MgCl2) solution had a prophylactic effect on dextran sulfate sodium (DSS)-induced colitis in mice, magnesium being considered to play a role in this preferable action. Magnesium oxide (MgO) is a commercially available magnesium formulation, but whether or not it prevents development of colitis is unknown. In this study, we investigated the effect of MgO administration on development of colitis in DSS-treated male C57BL/6J mice. Experimental colitis was induced by ad libitum ingestion of 1% (w/v) DSS, and the colitis severity was evaluated by disease activity index (DAI) scores, histological assessment and colonic expression of inflammatory cytokines. A 1 mg/mL MgO solution was administered to mice through ad libitum ingestion from a day before DSS treatment to the end of the experimental period of 12 d. In addition, the effects of DSS, MgO and their combination on the gut microbiota were investigated by 16S ribosomal RNA metagenome analysis. DSS-induced elevation of DAI scores was partially but significantly decreased by MgO administration, while MgO administration had no apparent effect on the shortened colonic length, elevated mRNA expression of colonic interleukin-1ß and tumor necrosis factor-α, increased accumulation of colonic mast cells, or altered features of the gut microbiota in DSS-treated mice. Overall, we demonstrated that MgO had a prophylactic effect on the development of colitis in DSS-treated mice by preventing histological colonic damage, but not colonic inflammation or alteration of the gut microbiota.

Dextran sulfate sodium-induced colitis in C57BL/6J mice increases their susceptibility to chronic unpredictable mild stress that induces depressive-like behavior.

AIMS: In patients with colitis, the high comorbidity of depressive disorders is well-known, but the detailed mechanisms remain unresolved. In this study, we examined whether colitis induced by dextran sulfate sodium (DSS) increased the susceptibility to chronic unpredictable mild stress (CUMS) in C57BL/6J mice with resilience to CUMS. MAIN METHODS: To induce experimental colitis and depressive-like behaviors, male 7-weeks old C57BL/6J mice were administered ad libitum 1% DSS solution for 11 days, and subjected to various mild stressors in a chronic, inevitable and unpredictable way according to a random schedule for 21 days, respectively. KEY FINDINGS: In naïve mice exposed to CUMS, their immobility times in a forced swim (FS) test were almost equal to those in control mice. The DSS administration to naïve mice induced colitis without depressive-like behavior, and at 18 days after termination of the DSS administration, the colitis had recovered to control levels, while altered diversity and composition of bacterial genera such as Bacteroides spp., Alistipes spp., etc., were found in the gut microbiota. Exposure of mice with DSS-induced colitis to CUMS (DSS + CUMS) significantly increased the immobility times in the FS test. In the gut microbiota of DSS + CUMS mice, the alteration profile of the relative abundance of bacterial genera differed from in the DSS ones. SIGNIFICANCE: These findings indicate that mice with colitis exhibit increased susceptibility to psychological stress, resulting in induction of depressive-like behavior, and this might be due, at least in part, to altered characteristics of the gut microbiota.

The effect of CYP3A5 genetic polymorphisms on adverse events in patients with ulcerative colitis treated with tacrolimus.

BACKGROUND: Tacrolimus is an immunosuppressive agent, used in the remission induction therapy of ulcerative colitis (UC). AIMS: We investigated the correlation between CYP3A5 genetic polymorphisms and the adverse events in patients with UC. The pharmacokinetics of tacrolimus after oral administration were also analyzed. METHODS: We enrolled 29 hospitalized patients with UC received oral tacrolimus. Genotyping for CYP3A5 A6986G (rs776746) was performed using Custom TaqMan® SNP genotyping assays. Adverse events, concentration and dose (C/D) ratios and clinical outcomes were investigated. RESULTS: CYP3A5 expressers and non-expressers were 16 and 13, respectively. C/D ratios of CYP3A5 expressers were significantly lower compared to non-expressers. The response rate in CYP3A5 non-expressers was relatively higher in the early phase of treatment compared to expressers, but not statistically significant. The incidence of overall adverse events was significantly higher in CYP3A5 expressers than in non-expressers (P=0.034, chi-squared test). In particular, the incidence of nephrotoxicity was significantly higher in CYP3A5 expressers compared to non-expressers (P=0.027, chi-squared test). All of the nephrotoxicity were reversible and resolved by discontinuation or dose reduction of tacrolimus. CONCLUSION: The adverse events especially nephrotoxicity were frequently observed in CYP3A5 expressers. CYP3A5 expressers should be paid attention to the onset of nephrotoxicity.

NUDT15 R139C-related thiopurine leukocytopenia is mediated by 6-thioguanine nucleotide-independent mechanism in Japanese patients with inflammatory bowel disease.

BACKGROUND: NUDT15 R139C (rs116855232) is a recently identified genetic factor responsible for thiopurine-induced leukocytopenia and hair loss. In this study, we investigated the association of NUDT15 R139C with 6-thioguanine nucleotide (6-TGN) levels and thiopurine-induced leukocytopenia in Japanese patients with inflammatory bowel disease (IBD). METHODS: Two hundred and sixty-four subjects (103 healthy volunteers and 161 IBD patients treated with thiopurines) were enrolled. Genotyping for NUDT15 R139C was performed using Custom TaqMan® SNP genotyping assays. RESULTS: The NUDT15 C/C, C/T, and T/T genotypes were 80.7, 18.2, and 1.1 %, respectively. The allelic frequency was 10.2 %. Among 161 IBD patients, there was no significant difference in 6-TGN levels among the NUDT15 genotypes. Forty-five patients (27.9 %) developed leukocytopenia (WBC <3000/µl), and the C/T and T/T genotypes were significantly associated with the development of leukocytopenia (P = 1.7 × 10(-5)). In these patients, 6-TGN levels were not significantly different between NUDT15 genotypes. NUDT15 R139C was significantly associated with early (<8 weeks) (P = 1.03 × 10(-4)) and late (>8 weeks) leukocytopenia (P = 4.3 × 10(-4)). The decrease in WBC count at 2 and 4 weeks was significantly higher in patients with the C/T or T/T genotypes as compared to the patients with the C/C genotype. All patients with the T/T genotype (n = 2) developed early severe hair loss and severe leukocytopenia (<1000/µl). The logistic regression analysis revealed that NUDT15 R139C was the sole genetic factor responsible for the thiopurine-induced leukocytopenia (P = 0.001). CONCLUSIONS: These results suggest that NUDT15 R139C-related thiopurine-induced leukocytopenia is mediated by a 6-TGN-independent mechanism.

MHC class I-related chain B gene polymorphism is associated with virological response to pegylated interferon plus ribavirin therapy in patients with chronic hepatitis C infection.

The outcome of antiviral therapy is associated with viral and host factors. In the present study, the association between MHC class I-related chain B (MICB) genotypes and therapeutic response to pegylated interferon plus ribavirin (PEG-IFN/RBV) therapy was investigated in hepatitis C virus (HCV)-infected patients. In total, 107 patients with chronic HCV infection (74 with HCV serotype 1 and 33 with serotype 2) were enrolled. Genotyping of MICB single-nucleotide polymorphism (SNP) rs3828913 and interleukin-28B (IL28B) SNP rs8099917 was performed using TaqMan® SNP genotyping assays. The genotype distribution of the MICB alleles was: CC, 79.4%; CA, 17.8%; and AA, 2.8%. Sustained virological response (SVR) was achieved by 55.1% (59/107) of the HCV patients. The SVR rate of patients with MICB major (CC) alleles was 62.3% and this rate was significantly higher than that of the patients with MICB minor (CA and AA) alleles (27.2%) (P=0.0068). A multivariate logistic model showed that the MICB major genotype was an independent factor contributing to SVR (OR, 4.47; 95% CI, 1.46-13.70; P=0.009). In addition, the MICB genotype was identified as the sole independent factor contributing to SVR and non-virological response in HCV serotype 1 patients with the IL28B major genotype. In HCV serotype 2 patients, the MICB genotype was the sole significant factor contributing to SVR (OR, 30.68; 95% CI, 2.72-346.3; P=0.006). In conclusion, the MICB genotype is a strong predictive factor for virological response to PEG-IFN/RBV therapy in HCV patients.