Hiroshi Tamagawa

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.

Characteristics of claudin expression in follicle-associated epithelium of Peyer's patches: Preferential localization of claudin-4 at the apex of the dome region

Gut-associated lymphoreticular tissues, such as Peyers patches and cecal patches, are important inductive sites for mucosal immune responses. As such, gut-associated lymphoreticular tissues may have an epithelial barrier different from that of villous epithelium. In this study, we investigated the immunohistochemical distribution of the claudin family and occludin in the follicle-associated epithelium (FAE) of Peyers patches and cecal patches of murine intestine. Unique profiles of claudin-2, -3, and -4 and occludin expression were noted in the tight junctions of the FAE: claudin-4 was preferentially expressed in the apex region; claudin-2 was only weakly expressed on the crypt side of the FAE compared with stronger expression on the crypt side of villous epithelial cells; and claudin-3 and occludin were found throughout the dome. These unique expression patterns were present also in cecal patch FAE. We also found that claudin-4 expression in the FAE of Peyers patches and cecal patches correlated with the presence of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling)-positive apoptotic cells, and Peyers patch-deficient mice exhibited expression patterns of claudin and occludin in villous epithelia similar to those in wild-type mice. We conclude that claudin-4 expression was preferentially associated with the dome region of FAE, the mucosal inductive site of the murine intestine. In that location it might correlate with the cell life cycle, help maintain the apex configuration of the dome, or be a factor favoring the uptake of antigens by the FAE.

The clinicopathological features of colorectal mucinous adenocarcinoma and a therapeutic strategy for the disease

BackgroundThe guidelines established by the National Comprehensive Cancer Network do not describe mucinous histology as a clinical factor that should influence the therapeutic algorithm. However, previous studies show conflicting results regarding the prognosis of colorectal mucinous adenocarcinoma. In this study, we described the clinicopathological features of mucinous adenocarcinoma in Japan, to identify optimal therapeutic strategies.Methods144 patients with mucinous and 2673 with non-mucinous adenocarcinomas who underwent primary resection in two major centers in Yokohama, Japan were retrospectively evaluated for clinicopathological features and treatment factors. A multivariate analysis for overall survival followed by the comparison of overall survival using Cox proportional hazard model were performed.ResultsPatients with mucinous adenocarcinoma had larger primary lesions, higher preoperative CEA levels, a deeper depth of invasion, higher rates of nodal and distant metastasis, and more metastatic sites. A multivariate analysis for overall survival revealed a mucinous histology to be an independent prognostic factor. In the subgroup analysis stratified by stage, Patients diagnosed as StageIII and IV disease had a worse survival in mucinous adenocarcinoma than non-mucinous, while survival did not differ significantly in patients diagnosed as Stage0-II disease. In StageIII, local recurrence in rectal cases and peritoneal dissemination were more frequently observed in patients with a mucinous histology.ConclusionsOur study indentified that mucinous adenocarcinoma was associated with a worse survival compared with non-mucinous in patients with StageIII and IV disease. In rectal StageIII disease with mucinous histology, additional therapy to control local recurrence followed by surgical resection may be a strategical alternative. Further molecular investigations considering genetic features of mucinous histology will lead to drug development and better management of peritoneal metastasis

Advantages of laparoscope-assisted surgery for recurrent Crohn's disease

BackgroundLaparoscopic surgery has been applied to patients with primary Crohns disease, and its beneficial outcomes have been already investigated. However, there is no systematic study of laparoscopic surgery for patients with recurrent diseases.MethodsWe performed reoperation for 43 patients with recurrent Crohns disease, including 23 patients who underwent laparoscope-assisted surgery.ResultsFor all the patients, laparoscope-assisted surgery could be performed safely, even if the patients had been treated previously by open surgery or had undergone multiple abdominal procedures. Conversion to open or hand-assisted laparoscopic surgery was necessary for 16 patients (69.6%) because of dense adhesions (11 cases) or bulky tumor (5 cases). Importantly, even if the procedure was converted, the skin incision was significantly shorter than with open surgery, and postoperative recovery was faster, especially for the patients who underwent conversion to hand-assisted laparoscopic surgery.ConclusionsLaparoscope-assisted surgery is feasible and advantageous in reoperation for patients with recurrent Crohns disease.

Randomized phase III study of bevacizumab plus FOLFIRI and bevacizumab plus mFOLFOX6 as first-line treatment for patients with metastatic colorectal cancer (WJOG4407G)

BACKGROUND FOLFIRI and FOLFOX have shown equivalent efficacy for metastatic colorectal cancer (mCRC), but their comparative effectiveness is unknown when combined with bevacizumab. PATIENTS AND METHODS WJOG4407G was a randomized, open-label, phase III trial conducted in Japan. Patients with previously untreated mCRC were randomized 1:1 to receive either FOLFIRI plus bevacizumab (FOLFIRI + Bev) or mFOLFOX6 plus bevacizumab (mFOLFOX6 + Bev), stratified by institution, adjuvant chemotherapy, and liver-limited disease. The primary end point was non-inferiority of FOLFIRI + Bev to mFOLFOX6 + Bev in progression-free survival (PFS), with an expected hazard ratio (HR) of 0.9 and non-inferiority margin of 1.25 (power 0.85, one-sided α-error 0.025). The secondary end points were response rate (RR), overall survival (OS), safety, and quality of life (QoL) during 18 months. This trial is registered to the University Hospital Medical Information Network, number UMIN000001396. RESULTS Among 402 patients enrolled from September 2008 to January 2012, 395 patients were eligible for efficacy analysis. The median PFS for FOLFIRI + Bev (n = 197) and mFOLFOX6 + Bev (n = 198) were 12.1 and 10.7 months, respectively [HR, 0.905; 95% confidence interval (CI) 0.723-1.133; P = 0.003 for non-inferiority]. The median OS for FOLFIRI + Bev and mFOLFOX6 + Bev were 31.4 and 30.1 months, respectively (HR, 0.990; 95% CI 0.785-1.249). The best overall RRs were 64% for FOLFIRI + Bev and 62% for mFOLFOX6 + Bev. The common grade 3 or higher adverse events were leukopenia (11% in FOLFIRI + Bev/5% in mFOLFOX6 + Bev), neutropenia (46%/35%), diarrhea (9%/5%), febrile neutropenia (5%/2%), peripheral neuropathy (0%/22%), and venous thromboembolism (6%/2%). The QoL assessed by FACT-C (TOI-PFC) and FACT/GOG-Ntx was favorable for FOLFIRI + Bev during 18 months. CONCLUSION FOLFIRI plus bevacizumab was non-inferior for PFS, compared with mFOLFOX6 plus bevacizumab, as the first-line systemic treatment for mCRC. CLINICAL TRIALS NUMBER UMIN000001396.

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.

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.

FOLFIRI plus bevacizumab as second-line therapy in patients with metastatic colorectal cancer after first-line bevacizumab plus oxaliplatin-based therapy: the randomized phase III EAGLE study

EAGLE was a randomized, multicenter phase III study which evaluated the superiority of bevacizumab 10 mg/kg plus FOLFIRI compared with bevacizumab 5 mg/kg plus FOLFIRI in patients with mCRC previously treated with first-line bevacizumab plus an oxaliplatin-based regimen. The results suggest that the higher 10 mg/kg dose offers no clear clinical benefit compared with bevacizumab 5 mg/kg in this setting.

Therapeutic effects of roxithromycin in interleukin-10-deficient colitis

Background A limited number of therapeutic strategies are currently available to treat patients with inflammatory bowel disease (IBD). Interleukin‐10 (IL‐10)—deficient mice, well characterized as an experimental model of IBD, develop severe chronic colitis because of aberrant Th1 responses. Roxithromycin (RXM), a macrolide antibiotic, has received attention because it offers not only antibacterial but also immunosuppressive effects. We examined the immunosuppressive effect of RXM on the development of IBD. Methods To test the efficacy of short‐term administration of RXM, elder IL‐10‐deficient mice (16–20 weeks old) with established colitis were orally treated for 10 days with RXM (20 mg/kg per day). To test the long‐term preventive effects of RXM, for 20 weeks young adult IL‐10‐deficient mice (4–5 weeks old) also were administered RXM orally (20 mg/kg per day). Results The short‐term treatment‐oriented administration of RXM reduced the degree of inflammatory change and lowered serum amyloid A in IL‐10‐deficient mice with severe colitis. Mononuclear cells from the lamina propria of RXM‐treated large intestines showed lower production of IFN‐&ggr; than did those from diseased mice that were untreated. Long‐term prevention‐oriented administration of RXM suppressed the development of severe colitis and decreased production of IFN‐&ggr; and IL‐12. In addition to its expected immunosuppressive effect, RXM treatment also decreased the level of Bacteroides vulgatus, a Gram‐negative anaerobe. Conclusions The anti‐inflammatory changes observed in IL‐10‐deficient mice resulted from the efficacy of RXM as an immunosuppressant as well as from its efficacy as an antibiotic. According to our findings, RXM would seem to have significant potential as a preventive and/or therapeutic agent for IBD. (Inflamm Bowel Dis 2007)