Published papers

Intestinal immune homeostasis is regulated by gut microbiota, including beneficial and pathogenic microorganisms. Imbalance in gut bacterial constituents provokes host proinflammatory responses causing diseases such as inflammatory bowel disease (IBD). The development of next-generation sequencing technology allows the identification of microbiota alterations in IBD. Several studies have shown reduced diversity in the gut microbiota of patients with IBD. Advances in gnotobiotic technology have made possible analysis of the role of specific bacterial strains in immune cells in the intestine. Using these techniques, we have shown that Clostridium butyricum as a probiotic induces interleukin-10-producing macrophages in inflamed mucosa via the Toll-like receptor 2/myeloid differentiation primary response gene 88 pathway to prevent acute experimental colitis. In this review, we focus on the new approaches for the role of specific bacterial strains in immunological responses, as well as the potential of bacterial therapy for IBD treatments.

A nationwide survey of liver cirrhosis (LC) was un- dertaken by asking major hospitals in Japan to provide information on the number of patients with LC admit- ted in 2012 along with information related to etiology including alcohol history. Etiological agents were as fol- lows: hepatitis B virus (10.5％), hepatitis C virus (47.1％), and alcohol (24.6％). Of LC cases, 30.6％ were alcohol- related (ethanol intake >60 g day). Among alcoholic LC (Al-LC) patients, mean age was older in the present study in 2012 compared with the data for 2007-2008. Our survey revealed that the prevalence of Al-LC has been rapidly increasing in Japan. Moreover, age was identified as risk factors for development of Al-LC.

Colonization with a mixture of Clostridium species has been shown to induce accumulation of induced regulatory T (iTreg) cells in the colon. Transforming growth factor-β (TGF-β) is an essential factor for iTreg cell induction; however, the relationship between Clostridium species and TGF-β remains to be clarified. Here we demonstrated that a gram-positive probiotic bacterial strain, Clostridium butyricum (C. butyricum), promoted iTreg cell generation in the intestine through induction of TGF-β1 from lamina propria dendritic cells (LPDCs). C. butyricum-mediated TGF-β1 induction was mainly Toll-like receptor 2 (TLR2) dependent, and the ERK-AP-1 kinase pathway played an important role. In addition, the autocrine TGF-β-Smad3 transcription factor signal was necessary for robust TGF-β expression in DCs, whereas Smad2 negatively regulated TGF-β expression. Smad2-deficient DCs expressed higher concentrations of TGF-β and were tolerogenic for colitis models. This study reveals a novel mechanism of TGF-β induction by Clostridia through a cooperation between TLR2-AP-1 and TGF-β-Smad signaling pathways.

A 23-year-old woman developed aortitis during treatment with adalimumab (ADA) for ileocolic Crohn’s disease (CD). The patient complained of a high fever, abdominal pain, diarrhea, hematochezia and arthralgia. Although the ADA therapy resulted in immediate symptom improvement, after six weeks, she again complained of a low-grade fever and abdominal pain, whereas the CD-related symptoms did not worsen. Contrast-enhanced computed tomography revealed thoracoabdominal aortitis, and we therefore started treatment with prednisolone, which immediately improved the fever and abdominal pain. We subsequently tapered the dose of prednisolone and resumed the administration of ADA in order to maintain the CD remission. No further episodes of aortitis relapse were noted after restarting ADA, and the CD currently remains in remission. This is the first report of the onset of aortitis during ADA therapy for CD.

肝星細胞遊離コレステロール(Ch)代謝調節による肝線維化新規治療法開発について検討した。C57BL/6バックグラウンドの9週齢雄性ACAT1欠損マウスおよび野生型マウスを用いた。ACAT1がマウス肝星細胞の主要なアイソザイムで、ACAT2発現はほとんど認めなかった。ACAT1欠損が肝星細胞活性化に及ぼす影響が、遊離Ch蓄積に依存することを示唆した。CCL肝線維化モデルで、TLR4シグナルが欠損した状態では、ACAT1欠損は肝線維化進展に影響を及ぼさなかった。TLR4シグナルが欠損した状態でも、ACAT1欠損により肝星細胞の遊離Ch蓄積が有意に増強したが、CE蓄積には影響しなかった。TLR4シグナルが欠損している状態では、ACAT1欠損による反応性の増強は認めなかった。遊離Ch蓄積により増強したTLR4シグナルが、ACAT1欠損による肝線維化の増悪に重要な役割を果たすことが示唆された。

炎症性腸疾患(IBD)、とくに潰瘍性大腸炎(UC)、クローン病(CD)はいまだに病態の解明がなされていない。遺伝、環境、腸内細菌など複合的な要因により病態が引き起こされると考えられている。しかし、いまだに完全にヒトIBDと同様の病態を示すモデルはなく、さまざまな大腸炎動物モデルを知り、必要に応じて使い分ける必要がある。近年無菌マウスシステムが確立され、腸内細菌が宿主の免疫系を教育することが判明してきた。さらにCRISPR/Cas9を利用した新しい遺伝子改変システムが今後広範に利用されるであろう。(著者抄録)

Cytoapheresis (CAP) therapy is widely used in ulcerative colitis (UC) patients with moderate to severe activity in Japan. The aim of this study is to predict the need of operation after CAP therapy of UC patients on an individual level using an artificial neural network system (ANN). Ninety UC patients with moderate to severe activity were treated with CAP. Data on the patients' demographics, medication, clinical activity index (CAI) and efficacy of CAP were collected. Clinical data were divided into training data group and validation data group and analyzed using ANN to predict individual outcomes. The sensitivity and specificity of predictive expression by ANN were 0.96 and 0.97, respectively. Events of admission, operation, and use of immunomodulator, and efficacy of CAP were significantly correlated to the outcome. Requirement of operation after CAP therapy was successfully predicted by using ANN. This newly established ANN strategy would be used as powerful support of physicians in the clinical practice.

In East Asian countries, gastric cancer incidence is high, but detection rates for germline CDH1 mutations that cause hereditary diffuse gastric cancers (HDGCs) are low. Consequently, screens and genetic testing for HDGC are often considered unimportant. Since the first germline truncating CDH1 mutations in Japanese patients were reported, some HDGC cases have been reported, and some of these involve large germline rearrangements and de novo mutation of CDH1. New methods for mutation detection—such as multiplex ligation-dependent probe amplification, array comparative genomic hybridization, and exome sequencing—have become available, as have new experimental models, including novel gene-knockout mice and gastric organoids. Because of these advances, searches for candidate genes (e.g., CTNNA1, MAP3K6) and our understanding of HDGC pathogenesis have improved in recent years; moreover, there have been substantial changes in the field since the current HDGC consensus guidelines were released. This review focuses on recent issues and advances in the study of HDGC. For example, lobular breast cancer cases and de novo occurrences of DGC are unlikely to meet the existing criteria for genetic testing, but current evidence indicates that some such cases may be good candidates for genetic testing. It is important to recognize that HDGC is a syndrome and that lobular breast cancer can be the first manifestation of this syndrome. CDH1 testing, including analyses of large genomic rearrangements, should be recommended even in countries where few HDGC cases have been reported.

Hepatitis C virus (HCV) genotype 1 infections are significantly more difficult to eradicate with PEG-IFN/ribavirin therapy, compared to HCV genotype 2. The aim of this work is to investigate the difference of immunological impairments underlying this phenomenon. Pretreatment NKG2D expression on peripheral CD56+CD3+ lymphocytes and CD56+CD3-NK cells from cases of chronic hepatitis C were analyzed and assessed by treatment effect. Two strains of HCV were used to co-incubate with immune cells in vitro. NKG2D expression on peripheral CD56+CD3+ lymphocytes, but not NK cells, was significantly impaired in genotype 1 infection, compared to genotype 2. When peripheral blood mononuclear cells from healthy donors were co-incubated with TNS2J1, a genotype 1b/2a chimera strain, or with JFH1, a genotype 2a strain, genotype-specific decrease of NKG2D on CD56+CD3+ lymphocytes, but not NK cells, was observed. Pre-treatment NKG2D expression on peripheral CD56+CD3+ lymphocytes significantly correlated with reduction in serum HCV RNA levels from week 0 to week 4, and predicted treatment response. Ex vivo stimulation of peripheral CD56+CD3+ lymphocytes showed NKG2D expression-correlated IFN-γ production. In conclusion, Decreased NKG2D expression on CD56+CD3+ lymphocytes in chronic HCV genotype 1 infection predicts inferior treatment response to PEG-IFN/ribavirin therapy compared to genotype 2.

Background and Aims: Infliximab is an efficacious agent used for the induction and maintenance of remission in Crohn's disease (CD), and recent studies suggested that it may also prevent the recurrence of this disease after surgery. The present study was performed to assess the efficacy and safety of infliximab in the postoperative setting, and to identify whether combination treatment with thiopurines had any additional beneficial effect as compared to mono-therapy. Methods: We performed a retrospective cohort study to compare the efficacy of infliximab mono-therapy and combination treatment with a thiopurine in preventing recurrence after surgery. Results: Forty-one patients who received infliximab as maintenance treatment following surgery from May 2002 to April 2010 were identified. Twenty-four were naive to infliximab, and 17 who underwent surgery during infliximab treatment were continued on it following surgery. The median follow-up period was 27 months (range 12-66 months). All patients continued infliximab as maintenance treatment, but 10 required dose intensification due to clinical recurrence. Kaplan-Meier analysis demonstrated that the use of concomitant thiopurine was correlated with the continuation of infliximab treatment at an 8-week interval (log-rank test p = 0.018). The rate of adverse event was 9.8% with no patient experiencing severe adverse reactions. Conclusion: Infliximab appears to be safe and it prevented clinical recurrence after surgery. Concomitant thiopurine use predicted response toward continuation of therapy at an 8-week interval. Prospective controlled studies to assess the efficacy of combination treatment in the postoperative setting are warranted.

Intestinal immune homeostasis is regulated by gut microbiota, including beneficial and pathogenic microorganisms. Imbalance in gut bacterial constituents provokes host proinflammatory responses causing diseases such as inflammatory bowel disease (IBD). The development of next-generation sequencing technology allows the identification of microbiota alterations in IBD. Several studies have shown reduced diversity in the gut microbiota of patients with IBD. Advances in gnotobiotic technology have made possible analysis of the role of specific bacterial strains in immune cells in the intestine. Using these techniques, we have shown that Clostridium butyricum as a probiotic induces interleukin-10-producing macrophages in inflamed mucosa via the Toll-like receptor 2/myeloid differentiation primary response gene 88 pathway to prevent acute experimental colitis. In this review, we focus on the new approaches for the role of specific bacterial strains in immunological responses, as well as the potential of bacterial therapy for IBD treatments.