Cellular metabolic state and individual metabolites have been reported to regulate the functional phenotype of immune cells. Cytokine production by regulatory and inflammatory macrophages is thought to mainly involve fatty acid oxidation and glycolysis, respectively, which fuel mitochondrial oxidative phosphorylation. However, the association between metabolic pathways and the acquisition of specific macrophage phenotypes remains unclear. This study assessed the relationship between glycolysis and the differentiation of regulatory macrophages. Human monocytes derived from peripheral blood were cultured in vitro in the presence of macrophage colony-stimulating factor to yield regulatory macrophages (M-Mϕs). M-Mϕs had a regulatory macrophage phenotype and produced substantial IL-10 following stimulation with lipopolysaccharide. To analyze the role of glycolysis, glycolysis inhibitors (2-deoxy-d-glucose or dichloroacetate) were added during M-Mϕ differentiation. These cells cultured with glycolysis inhibitors produced significantly lower amounts of IL-10, but produced significantly higher amounts of IL-6 compared to M-Mϕs differentiated without glycolysis inhibitors. Such phenotypic change of M-Mϕs differentiated with glycolysis inhibitors was associated with the alteration of the gene expression pattern related to macrophage differentiation, such as CSF1, MMP9 and VEGFA. M-Mϕs differentiated with glycolysis inhibitors seemed to retain plasticity to become IL-10 producing cells. Furthermore, increased level of pyruvate in culture medium was found to partially reverse the effects of glycolysis inhibitors on cytokine production of M-Mϕs. These results indicate the importance of glycolytic pathway in macrophage differentiation to a regulatory phenotype, and pyruvate may be one of the key metabolites in this process.

Altered abundance and composition of the gut microbiota, i.e., dysbiosis, is reported to be involved in the pathogenesis of various diseases including not only gastrointestinal diseases but also metabolic, neurological, and autoimmune disorders. Fecal microbiota transplantation (FMT) aims to correct dysbiosis by administrating feces collected from donors and thus treat the underlying disease. Ulcerative colitis (UC) is a disease characterized by chronic inflammation in the large intestine. Patients with UC have been reported to have dysbiosis, and more specifically, reduced diversity and abundance of the gut microbiota. FMT has been tried as a treatment for UC. Favorable effects of FMT on UC had been reported in case reports or case series. Recently, four randomized controlled trials of FMT for UC were published. Three of the four studies reported that FMT was more effective than control treatment. Thus, FMT is considered as a promising treatment for UC; however, there are many issues to solve before FMT can become a standard therapy for UC including donor selection, administration routes, frequencies, easy-to-administer formulation development, and optimal patient population.

Background and Aims: Perianal lesion is a refractory phenotype of Crohn’s disease [CD] with significantly diminished quality of life. We evaluated the clinical characteristics of perianal lesions in newly diagnosed CD patients and the impact of perianal lesions on the quality of life in Japanese patients with CD. Methods: Patients newly diagnosed with CD after June 2016 were included between December 2018 and June 2020 from the Inception Cohort Registry Study of Patients with CD [iCREST-CD]. Results: Perianal lesions were present in 324 [48.2%] of 672 patients with newly diagnosed CD; 71.9% [233/324] were male. The prevalence of perianal lesions was higher in patients aged <40 years vs ≥40 years, and it decreased with age. Perianal fistula [59.9%] and abscess [30.6%] were the most common perianal lesions. In multivariate analyses, male sex, age <40 years and ileocolonic disease location were significantly associated with a high prevalence of perianal lesions, whereas stricturing behaviour and alcohol intake were associated with low prevalence. Fatigue was more frequent [33.3% vs 21.6%] while work productivity and activity impairment-work time missed [36.3% vs 29.5%] and activity impairment [51.9% vs 41.1%] were numerically higher in patients with than those without perianal lesions. Conclusions: At the time of CD diagnosis, approximately half of the patients had perianal lesions; perianal abscesses and perianal fistulas were the most common. Young age, male sex, disease location and behaviour were significantly associated with the presence of perianal lesions. The presence of perianal lesion was associated with fatigue and impairment of daily activities. Clinical trials registry: University Hospital Medical Information Network Clinical Trials Registry System [UMIN-CTR, UMIN000032237].

Thiopurine has been used to maintain remission and to reduce antidrug antibody formation in monoclonal antibody therapy in patients with inflammatory bowel disease (IBD). The use of thiopurine is limited by side effects such as leukopenia. Thiopurine S-methyltransferase (TPMT) variants are associated with thiopurine-induced leukopenia in Westerners, but the frequency of the risk alleles is low in Asians. Recently, a variant in the nudix hydrolase 15 (NUDT15) gene (R139C, c.415C > T) was reported to be associated with early severe leukopenia in Asians. NUDT15 is an enzyme that converts 6-thio-(deoxy)guanosine triphosphate (6-T(d)GTP) to 6-thio-(deoxy)guanosine monophosphate (6-T(d)GMTP). The R139C variant impairs the stability of the protein and increases incorporation of 6-TGTP and 6-TdGTP into RNA and DNA, respectively, resulting in leukopenia. The frequency of C/C, C/T, and T/T are approximately 80%, 20%, and 1%, respectively in East Asians. Early leukopenia occurred in less than 3% of patients with C/C and in around 20% of those with C/T, whereas it occurred in almost all patients with T/T. Patients homozygous for this variant also develop severe hair loss. The measurement of NUDT15 R139C can increase the safety of thiopurine dramatically and is a successful example of personalized medicine in the field of IBD.