Yasuyuki Kai

A Novel Sphingosine 1-Phosphate Receptor Agonist, 2-Amino-2-propanediol Hydrochloride (KRP-203), Regulates Chronic Colitis in Interleukin-10 Gene-Deficient Mice

Current treatments for patients with Crohns disease (CD) are based on recent advances in elucidating the pathophysiology of the disease. A satisfactory therapeutic strategy has not been well established. A new sphingosine 1-phosphate (S1P) receptor agonist, 2-amino-2-propanediol hydrochloride (KRP-203), has been developed for immunomodulation in autoimmune diseases and organ transplantation. We aimed to evaluate the efficacy and potency of KRP-203 on the treatment of chronic colitis in an interleukin (IL)-10 gene-deficient (IL-10–/–) mouse model. KRP-203 agonistic activity on S1P receptor was assessed in vitro. KRP-203 was administered for 1 or 4 weeks to IL-10–/– mice with clinical signs of colitis. The histological appearance of the colon and the numbers, phenotype, and cytokine production of lymphocytes were compared with a control group. KRP-203 treatment was effective in preventing body weight loss in the IL-10–/– colitis model. One-week administration resulted in the sequestration of circulating lymphocytes within the secondary lymphoid tissues. After 4 weeks of treatment, highly significant reductions were observed in number of CD4+ T cell and B220+ B cell subpopulations in the lamina propria of the colon and peripheral blood. KRP-203 obviously inhibited the production of interferon-γ, IL-12, and tumor necrosis factor-α by the colonic lymphocytes, but had no influence on IL-4 production. KRP-203 significantly inhibits ongoing IL-10–/– colitis in part through decreasing the infiltration of lymphocytes at inflammatory sites and by blocking T-helper 1 cytokine production in the colonic mucosa. Therefore, the possibility arises that KRP-203 plays a potential role in control of chronic colitis.

Alteration of Vβ Usage and Cytokine Production of CD4+ TCR ββ Homodimer T Cells by Elimination of Bacteroides vulgatus Prevents Colitis in TCR α-Chain-Deficient Mice

A major pathogenic factor for the development of inflammatory bowel disease (IBD) is the breakdown of the intestinal homeostasis between the host immune system and the luminal microenvironment. To assess the potential influence of luminal Ags on the development of IBD, we fed TCR α−/− mice an elemental diet (ED). ED-fed TCR α−/− mice showed no pathologic features of IBD, and their aberrant mucosal B cell responses were suppressed. Similar numbers of CD4+, TCR ββ homodimer T cells (ββ T cells) were developed in the colonic mucosa of ED-fed mice; however, Th2-type cytokine productions were lower than those seen in diseased regular diet (RD)-fed mice. The higher cytokine production in diseased RD-fed mice could be attributed to the high incidence of Bacteroides vulgatus (recovered in 80% of these mice), which can induce Th2-type responses of colonic CD4+, ββ T cells. In contrast, ED-fed TCR α−/− mice exhibited a diversification of Vβ usage of ββT cell populations from the dominant Vβ8 one associated with B. vulgatus in cecal flora to Vβ6, Vβ11, and Vβ14. Rectal administration of disease-free ED-fed mice with B. vulgatus resulted in the development of Th2-type CD4+, ββ T cell-induced colitis. These findings suggest that the ED-induced alteration of intestinal microenvironments such as the enteric flora prevented the development of IBD in TCR α−/− mice via the immunologic quiescence of CD4+, ββ T cells.

Therapeutic effects of a new lymphocyte homing reagent FTY720 in interleukin-10 gene-deficient mice with colitis

Background:FTY720 is a novel reagent that possesses potent immunosuppressive activity. The immunosuppression induced by FTY720 is mediated by completely different mechanisms from those of conventional immunosuppressants, that is, by altering the tissue distribution of lymphocytes rather than inhibiting activation. In this study, we examined the efficacy of FTY720 in the treatment of chronic colitis in an interleukin-10 gene-deficient (IL-10−/−) mouse model. Methods:FTY720 was administered orally for 4 weeks to IL-10−/−mice with clinical signs of colitis. The gross and histologic appearance of the colon and the numbers, phenotype, cytokine production, and apoptosis of lymphocytes were compared with those characteristics in a control group. Results:Single-dose administration of FTY720 resulted in the sequestration of circulating lymphocytes within the secondary lymphoid tissues. Four-week administration resulted in a significant reduction of the CD4+ T lymphocytes subpopulation in the colonic lamina propria and IFN-γ production of the colonic lymphocytes, accompanied by a significant decrease in the severity of colitis. Conclusions:Treatment of established colitis in IL-10−/− mice with FTY720 ameliorated the colitis, probably as a result of decreasing the number of lymphocytes in the colonic mucosa and an associated reduction in IFN-γ production.

Therapeutic effects of novel sphingosine-1-phosphate receptor agonist W-061 in murine DSS colitis.

Although IL-17 is a pro-inflammatory cytokine reportedly involved in various autoimmune inflammatory disorders, its role remains unclear in murine models of colitis. Acute colitis was induced by 2.5% dextran sodium sulfate (DSS) treatment for 5 days. A novel sphingosine-1-phosphate receptor agonist W-061, a prototype of ONO-4641, was orally administered daily, and histopathological analysis was performed on the colon. The number of lymphocytes and their cytokine production were also evaluated in spleen, mesenteric lymph node, Peyers patch and lamina propria of the colon. Daily administration of W-061 resulted in improvement of DSS-induced colitis, and significantly reduced the number of CD4+ T cells in the colonic lamina propria. Numbers of both Th17 and Th1 cells were reduced by W-061 treatment. W-061, however, had no influence on the number of Treg cells in lamina propria. Thus, Th17 and Th1 cells in lamina propria were thought to be the key subsets in the pathogenesis of DSS-induced colitis. In conclusion, W-061 may be a novel therapeutic strategy to ameliorate acute aggravation of inflammatory bowel diseases.

Therapeutic effect of a new immunosuppressive agent, everolimus, on interleukin-10 gene-deficient mice with colitis

A limited number of therapeutic strategies are currently available for patients with inflammatory bowel disease (IBD). In particular, the maintenance therapy after remission in Crohns disease (CD) is not satisfactory and new approaches are needed. Interleukin‐10 gene‐deficient (IL‐10–/–) mice, a well‐characterized experimental model of CD, develop severe chronic colitis due to an aberrant Th1 immune response. Everolimus, an inhibitor of the mammalian target of rapamycin (mTOR), a new immunosuppressive reagent, has been used successfully in animal models for heart, liver, lung and kidney transplantation. In the present study, we examined the efficacy of everolimus in the treatment of chronic colitis in an IL‐10–/– mouse model. Everolimus was administered orally for a period of 4 weeks to IL‐10–/– mice with clinical signs of colitis. The gross and histological appearances of the colon and the numbers, phenotype and cytokine production of lymphocytes were compared with these characteristics in a control group. The 4‐week administration of everolimus resulted in a significant decrease in the severity of colitis, together with a significant reduction in the number of CD4+ T cells in the colonic lamina propria as well as IFN‐γ production in colonic lymphocytes. Everolimus treatment of established colitis in IL‐10–/– mice ameliorated the colitis, probably as a result of decreasing the number of CD4+ T cells in the colonic mucosa and an associated reduction in IFN‐γ production.

Malignancy in Crohn’s Disease: Incidence and Clinical Characteristics in Japan

Background/Aims: This study investigated the occurrence of malignancies in Japanese patients with Crohn’s disease (CD) and compared the incidence with that in the general population. Methods: The medical records of 294 CD patients, treated between 1989 and 2009, were reviewed and the prevalence of malignancies was assessed. Registration of person-years at risk was calculated individually, from the year of CD diagnosis until the year of cancer diagnosis, death or end of follow-up. The observed number of cancer cases was compared with the expected number, calculated on the basis of the individually computed person-years at risk and the corresponding age- and sex-specific incidence rates in the background population. Results: Thirteen cancers developed in 12 patients among a total of 4,248 person-years available for analysis. There were six CRCs, two gastric cancers, two uterine cancers, one small bowel cancer, one biliary cancer, and one cancer of unknown primary site. The risk of cancer (all sites) was significantly increased from that of the background population; SIR 2.24 (95% CI 1.19–3.83). In particular, the risk of CRC significantly increased in comparison to that of the background population; SIR 5.80 (95% CI 2.13–12.68). Conclusions: Japanese patients with CD are at increased risk of cancer, particularly CRC.

The effect of Clostridium butyricum MIYAIRI on the prevention of pouchitis and alteration of the microbiota profile in patients with ulcerative colitis

PurposeUlcerative colitis (UC) is a chronic, relapsing, and refractory disorder of the intestine. Total proctocolectomy with ileal pouch anal anastomosis (IPAA) is the preferred and standard surgical procedure for patients’ refractory to medical therapy. Pouchitis is one of the most common long-term complications after IPAA. In the present study, the safety and efficacy of Clostridium butyricum MIYAIRI (CBM) as a probiotic were examined.MethodsA randomized and placebo-controlled study was performed. Seventeen patients were recruited from 2007 to 2013. Nine tablets of MIYA-BM® or placebo were orally administered once daily. The cumulative pouchitis-free survival, pouch condition (using the modified pouch disease activity index), and blood parameters were evaluated. A fecal sample analysis was also performed.ResultsSubjects were randomly allocated to receive MIYA-BM or placebo (9 and 8 subjects, respectively). One subject in the MIYA-BM group and four subjects in the placebo group developed pouchitis. No side effects occurred in either group. Characteristic intestinal flora was observed in each group.ConclusionsOur results suggest that probiotic therapy with CBM achieved favorable results with minimal side effects and might be a useful complementary therapy for the prevention of pouchitis in patients with UC who have undergone IPAA.

Development of Colitis in Signal Transducers and Activators of Transcription 6-Deficient T-Cell Receptor α-Deficient Mice: A Potential Role of Signal Transducers and Activators of Transcription 6-Independent Interleukin-4 Signaling for the Generation of Th2-Biased Pathological CD4+ββT Cells

Forbidden CD4(+)betabeta T cells, which produce interleukin (IL)-4 predominantly, are a pathological subset in the development of colitis in T-cell receptor alpha chain (TCRalpha)-deficient mice. Stimulation of naive CD4(+) T cells with IL-4 induces Th2 development via the activation of signal transducers and activators of transcription (STAT) 6. In the present study, we had found that IL-4 enhanced the expression of STAT6 in CD4(+)betabeta T cells isolated from TCRalpha(-/-) mice with colitis, suggesting that the IL-4 signal in the CD4(+)betabeta T cells is mediated by STAT6. To further investigate the role of STAT6 in the development of colitis induced by TCRalpha deficiency, we generated double-deficient mice by crossing TCRalpha(-/-) mice and STAT6(-/-) mice. Surprisingly, STAT6 deficiency did not result in decreased severity of colitis in TCRalpha(-/-) mice. STAT6-deficient CD4(+)betabeta T cells produced IL-4 and intraperitoneal injection of anti-IL-4 monoclonal antibody in the nondiseased TCRalpha(-/-) and STAT6 double-deficient mice prevented the colitis formation, thus indicating that the cells differentiated into the Th2 phenotype have the ability to mediate the development of the colitis in the absence of STAT6.

A Simple Application Technique of Fibrin-Coated Collagen Fleece (TachoComb) in Laparoscopic Surgery

A fibrin-coated collagen fleece (TachoComb, Nycomed, Denmark) is a powerful topical hemostatic agent, which has been aggressively used in conventional open surgery with a favorable clinical outcome. However, the use of TachoComb in laparoscopic surgery has not yet gained wide clinical acceptance, because a simple and well-functioning application system is not available. The authors have newly developed a quick, simple, and effective laparoscopic TachoComb application technique: housing a small strip of TachoComb in a rubber tube, then conveying it into the peritoneal cavity, and applying it using standard laparoscopic forceps. The repeated application of TachoComb strips is feasible and of practical value especially in laparoscopic surgery, since a small TachoComb never compromises either the application procedure or laparoscopic visualization.

Influence of enterotoxin on mucosal intranet: selective inhibition of extrathymic T cell development in intestinal intraepithelial lymphocytes by oral exposure to heat-labile toxin

We tested the possibility that heat‐labile enterotoxin of Escherichia coli (LT) affects the development of extrathymic T cells in the intraepithelial lymphocyte (IEL) compartment. After oral administration of LT, the number of extrathymic CD8α α+ IEL was selectively and significantly diminished when compared with the corresponding cells in phosphate‐buffered saline‐fed control mice. To clarify the mechanism behind this selective reduction of CD8α α+ IEL, we analyzed the expression of essential cytokines and their corresponding receptors for the mucosal intranet formed by intestinal epithelial cells (IEC) and IEL. The expression levels of stem cell factor, interleukin (IL)‐7, and IL‐15 in IEC, and their corresponding receptors, i. e. c‐kit, IL‐7 receptor, and IL‐15 receptor, in CD8α α+ IEL were reduced following oral feeding with LT. These findings suggest that LT negatively regulates development of CD8α α+ IEL via the disruption of mucosal intranet‐associated cytokine and cytokine receptors, which are required for the development and / or expansion of extrathymically developedT cells. Further, LT‐induced destruction of the mucosal intranet resulted in the impairment of IEC generation via an increase of apoptosis.