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Loss-of-function mutations in the solute carrier organic anion transporter family, member 2a1 gene (SLCO2A1), which encodes a prostaglandin (PG) transporter, have been identified as causes of chronic nonspecific multiple ulcers in the small intestine; however, the underlying mechanisms have not been revealed. We, therefore, evaluated the effects of systemic knockout of Slco2a1 (Slco2a1−/−) and conditional knockout in intestinal epithelial cells (Slco2a1ΔIEC) and macrophages (Slco2a1ΔMP) in mice with dextran sodium sulphate (DSS)-induced acute colitis. Slco2a−/− mice were more susceptible to DSS-induced colitis than wild-type (WT) mice, but did not spontaneously develop enteritis or colitis. The nucleotide-binding domain, leucine-rich repeats containing family, pyrin domain-containing-3 (NLRP3) inflammasome was more strongly upregulated in colon tissues of Slco2a−/− mice administered DSS and in macrophages isolated from Slco2a1−/− mice than in the WT counterparts. Slco2a1ΔMP, but not Slco2a1ΔIEC mice, were more susceptible to DSS-induced colitis than WT mice, partly phenocopying Slco2a−/− mice. Concentrations of PGE2 in colon tissues and macrophages from Slco2a1−/− mice were significantly higher than those of WT mice. Blockade of inflammasome activation suppressed the exacerbation of colitis. These results indicated that Slco2a1-deficiency increases the PGE2 concentration, resulting in NLRP3 inflammasome activation in macrophages, thus exacerbating intestinal inflammation. [ABSTRACT FROM AUTHOR]

Objectives: Although tacrolimus is useful as an induction therapy in patients with ulcerative colitis (UC), information regarding the long-term outcome after tacrolimus therapy is insufficient. The aim of this study was to evaluate the clinical significance of the pretreatment neutrophil-to-lymphocyte ratio (NLR) as a prognostic factor in patients with UC receiving tacrolimus, to aid treatment selection. Materials and methods: Patients with moderate-to-severe active UC who received oral tacrolimus induction therapy and subsequent immunomodulatory maintenance therapy at our hospital between 2009 and 2017 and who showed clinical response at week 12, were retrospectively enrolled. Cox regression analysis was conducted to study the prognostic role of the pretreatment NLR. The combined impact of the NLR and other known prognostic factors was investigated with multivariate regression. Results: Among 45 patients included in this study, 21 patients experienced relapse during a median follow-up period of 16.6 months. Multivariate Cox regression analysis identified the pretreatment NLR (hazard ratio [HR]: 0.82, 95% confidence interval [CI]: 0.72–0.94, P < 0.01) and the use of immunomodulators at the start of tacrolimus treatment (HR: 0.18, 95% CI: 0.05–0.66, P = 0.01) as independent predictors of clinical relapse. Conclusions: The pretreatment NLR is an independent prognostic factor in patients with UC treated with tacrolimus. [ABSTRACT FROM AUTHOR]