Tsukasa Ishida

Resolvin E1, an endogenous lipid mediator derived from eicosapentaenoic acid, prevents dextran sulfate sodium-induced colitis

Background: Resolvin E1 (RvE1), an endogenous lipid mediator derived from eicosapentaenoic acid, has been identified in local inflammation during the healing stage. RvE1 reduces inflammation in several types of animal models including peritonitis and retinopathy and blocks human neutrophil transendothelial cell migration. The RvE1 receptor ChemR23 is expressed on myeloid cells such as macrophages and dendritic cells. The aim of this study was to determine whether RvE1 regulates colonic inflammation when the innate immune response of macrophages plays a key role in pathogenesis and tissue damage. Methods: The RvE1 receptor ChemR23 was expressed in mouse peritoneal macrophages as defined by flow cytometry. Peritoneal macrophages were pretreated with RvE1, followed by lipopolysaccharide stimulation, whereupon transcriptional levels of proinflammatory cytokines were analyzed. Results: RvE1 treatment led to inhibition of proinflammatory cytokines including TNF‐&agr; and IL‐12p40. In HEK293 cells, pretreatment with RvE1 inhibited TNF‐&agr;‐induced nuclear translocation of NF‐&kgr;B in a ChemR23‐dependent manner. These results suggested that RvE1 could regulate proinflammatory responses of macrophages expressing ChemR23. Therefore, we investigated the beneficial effects of RvE1 in dextran sulfate sodium–induced colitis. RvE1 treatment led to amelioration of colonic inflammation. Conclusions: These results indicate that RvE1 suppresses proinflammatory responses of macrophages. RvE1 and its receptor may therefore be useful as therapeutic targets in the treatment of human inflammatory bowel disease and other inflammatory disorders. Inflamm Bowel Dis 2010

Lipoxin A4 Reduces Lipopolysaccharide-Induced Inflammation in Macrophages and Intestinal Epithelial Cells through Inhibition of Nuclear Factor-κB Activation

Lipoxins, which are bioactive lipids derived from ω-6 polyunsaturated fatty acids, play important roles in various biological functions. In this study, the anti-inflammatory effects of lipoxin A4 (LXA4; 5S,6R,15S-trihydroxy-7,9,13-trans-11-eicosatetraenoic acid) were investigated in in vitro cultured cell experiments and in vivo animal experiments. In mouse peritoneal macrophages and mouse macrophage cell line RAW264.7 cells, LXA4 reduced the lipopolysaccharide (LPS)-induced increase in the mRNA expression level of tumor necrosis factor (TNF)-α. LXA4 also reduced the LPS-induced nuclear translocation of nuclear factor-κB (NF-κB). In an LPS-induced acute inflammation mouse model, the injection of LXA4 at 5 μg/kg b.wt. led to down-regulation of the TNF-α level in serum and the TNF-α mRNA expression level in intestinal epithelial cells. Moreover, LXA4 reduced the LPS-caused phosphorylation of IκB kinases, IκB, and NF-κB, the degradation of IκB, and the nuclear translocation of NF-κB in intestinal epithelial cells. In a coculture system using RAW264.7 cells and human colon carcinoma cell line Caco-2 cells, treatment with LXA4 to Caco-2 cells led to reduction of LPS-evoked TNF-α production in RAW264.7 cells and interleukin-8 mRNA expression in Caco-2 cells. These results indicate that LXA4 exerts anti-inflammatory effects through inhibition of NF-κB activation, and, therefore, LXA4 may be useful as a therapeutic strategy against intestinal mucosa inflammation.

Lactococcus lactis subsp. cremoris FC alleviates symptoms of colitis induced by dextran sulfate sodium in mice.

Probiotics have been used to treat human gastrointestinal inflammations including inflammatory bowel disease (IBD). However, the exact mechanisms by which probiotics act to protect against intestinal inflammation have yet to be fully elucidated. The aim of this study was to evaluate anti-inflammatory effects of Lactococcus lactis subsp. cremoris FC using in vivo and in vitro inflammation models. Colitis was induced in C57BL/6 mice by administration of 3% dextran sulfate sodium to drinking water. In the cellular level assessment, a gut inflammation model with the co-culture system consisting Caco-2 cells and RAW264.7 cells stimulated by LPS was used. Administration of L. lactis subsp. cremoris FC significantly ameliorated shortening of colon length and histological score of the colon in DSS-induce colitis mice. In addition, the treatment of L. lactis subsp. cremoris FC improved the aberrant mRNA expression in inflamed tissue near to control level through notable suppression of TNF-alpha (P<0.05), IFN-gamma (P<0.05), IL-6, iNOS, and MIP-2 mRNA expression. In addition, in a gut inflammation model, treatment with L. lactis subsp. cremoris FC resulted in significant down-regulation of IL-8 mRNA expression in Caco-2 cells and inhibition of NF-kappaB nuclear translocation in RAW264.7 cells. Our findings indicate that administration of L. lactis subsp. cremoris FC improves negative effects of DSS-induced colitis in mice through the inhibition of inflammatory cell infiltration.

Inhibitory Effects of Glycyrrhetinic Acid on DNA Polymerase and Inflammatory Activities

We investigated the inhibitory effect of three glycyrrhizin derivatives, such as Glycyrrhizin (compound 1), dipotassium glycyrrhizate (compound 2) and glycyrrhetinic acid (compound 3), on the activity of mammalian pols. Among these derivatives, compound 3 was the strongest inhibitor of mammalian pols α, β, κ, and λ, which belong to the B, A, Y, and X families of pols, respectively, whereas compounds 1 and 2 showed moderate inhibition. Among the these derivatives tested, compound 3 displayed strongest suppression of the production of tumor necrosis factor-α (TNF-α) induced by lipopolysaccharide (LPS) in a cell-culture system using mouse macrophages RAW264.7 and peritoneal macrophages derived from mice. Moreover, compound 3 was found to inhibit the action of nuclear factor-κB (NF-κB) in engineered human embryonic kidney (HEK) 293 cells. In addition, compound 3 caused greater reduction of 12-O-tetradecanoylphorbol-13-acetate-(TPA-) induced acute inflammation in mouse ear than compounds 1 and 2. In conclusion, this study has identified compound 3, which is the aglycone of compounds 1 and 2, as a promising anti-inflammatory candidate based on mammalian pol inhibition.

Fcγ Receptor Regulation of Citrobacter rodentium Infection

ABSTRACT Citrobacter rodentium, a murine model pathogen for enteropathogenic Escherichia coli, colonizes the colon utilizing attaching and effacing lesions to adhere specifically to the surfaces of intestinal epithelial cells and cause mucosal inflammation. CD4+ T cells, B cells, and immunoglobulin G (IgG), but not secretory IgA or IgM, play a critical role in eradicating this pathogen. Consistent with the importance of IgG in C. rodentium eradication, IgG transport by the neonatal Fc receptor for IgG within the intestinal epithelium also has a critical role in the regulation of C. rodentium infection. It remains to be determined, however, whether Fcγ receptors (FcγRs), the receptors for the Fc portion of IgG, regulate this bacterial infection within mucosal tissues. Therefore, we investigated the roles of FcγRs during C. rodentium infection. Fc receptor common gamma chain (FcRγ)-deficient mice were more susceptible to C. rodentium-induced colitis. This occurred through decreased efficiency of FcR-mediated endocytosis and maturation of dendritic cells and consequently T-cell activation of antigen-specific T cells. Moreover, in the absence of FcγRs, phagocytosis by macrophages was significantly diminished. Therefore, activating FcγRs play an important role in defending against C. rodentium infection, indicating that the critical role played by IgG in this infection is not mediated by IgG alone but is dependent upon this class of receptors.

Disseminated nocardiosis during systemic steroid therapy for the prevention of esophageal stricture after endoscopic submucosal dissection

An 85‐year‐old man underwent endoscopic submucosal dissection for a large superficial esophageal epithelial neoplasm, which required removal of 95% of the circumference of the esophageal mucosa. Steroids were given orally to prevent esophageal stricture starting on day 3 postoperatively. In the 6th week of steroid treatment, he developed high fever without other symptoms. Chest computed tomography revealed a nodular lesion in the lung. Sputum sample showed Gram‐positive, branching, filamentous bacteria, and a diagnosis of nocardiosis was suspected. Brain magnetic resonance imaging revealed multiple focal lesions which indicated dissemination of nocardiosis. Trimethoprim‐sulfamethoxazole was immediately started, which led to the disappearance of pulmonary and cerebral nocardiosis with alleviation of fever. Recently, oral steroid treatment has been widely used for the prevention of esophageal stricture. However, the present case indicates the risk of life‐threatening infection and the importance of close monitoring of this treatment.

Endoscopic submucosal dissection of cecal lesions in proximity to the appendiceal orifice

BACKGROUND AND STUDY AIMS Endoscopic submucosal dissection (ESD) is performed for treatment of various gastrointestinal lesions; however, the cecum in proximity to the appendiceal orifice remains a challenging area. We reviewed our experience with cecal ESD near the appendiceal orifice in order to clarify whether this procedure is a safe and effective therapeutic option. PATIENTS AND METHODS We retrospectively reviewed ESD for lesions within approximately 12 mm of the appendiceal orifice at Kobe University Hospital and an affiliated hospital between January 2003 and December 2014. Lesions were classified as: Type 0, proximity to the appendiceal orifice but does not reach it; Type 1, reaches border of the appendix, but does not enter orifice; Type 2, enters orifice, and transition to normal appendiceal mucosa is discernible on inspection of the appendiceal lumen; and Type 3, enters orifice deeply and tumor edge cannot be observed. ESD was not performed for Type 3 lesions unless appendectomy was performed prior to ESD. RESULTS A total of 76 lesions satisfied the inclusion criteria (47 Type 0 lesions, 20 Type 1, 6 Type 2, and 3 Type 3). En bloc resection was achieved in 72 lesions (94.7 %). Median specimen size was 49 mm (range 15 - 114 mm), and median tumor size was 35.5 mm (10 - 110 mm). One patient experienced postoperative bleeding, which was treated by endoscopic hemostasis. Another patient who experienced intraoperative perforation and was treated by clip closure later developed appendicitis; he underwent emergency ileocecal surgical resection. Another patient experienced postoperative appendicitis and recovered with antibiotic treatment. CONCLUSIONS ESD in close proximity to the appendiceal orifice seems safe and effective.

Efficacy of endoscopic submucosal dissection for residual or recurrent superficial colorectal tumors after endoscopic mucosal resection

Superficial colorectal tumors can be treated effectively by endoscopic submucosal dissection (ESD). Few data are available on using ESD for residual or recurrent tumors after the first endoscopic resection. This study aimed to evaluate the efficacy of ESD for these lesions.

Linoleoyl ethanolamide reduces lipopolysaccharide-induced inflammation in macrophages and ameliorates 2,4-dinitrofluorobenzene-induced contact dermatitis in mice.

In our previous study, it was found that linoleoyl ethanolamide (LE) is present in sake lees, which are produced as a byproduct during the making of Japanese sake. LE is a fatty acid ethanolamide, which have been demonstrated to exert a variety of biological functions, and in this study, the anti-inflammatory effects of LE were examined using in vitro cell culture and in vivo animal experiments. In mouse RAW264.7 macrophages, LE suppressed the lipopolysaccharide (LPS)-induced expression of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. In addition, LE inhibited LPS-induced increases in the levels of cyclooxygenase enzyme-2 and prostaglandin E(2), which are indicators of inflammation. The inhibitory effect of LE on the release of TNF-α was stronger than that of dipotassium glycyrrhizinate, which is widely used in external human skin care treatments. LE also suppressed the LPS-induced activation of Toll-like receptor 4 signaling and nuclear translocation of nuclear factor-κB (NF-κB) p65. In a contact dermatitis animal model, applying LE to affected ear skin ameliorated 2,4-dinitrofluorobenzene-induced contact dermatitis and pro-inflammatory cytokine expression at inflamed sites. These results indicate that LE exerts anti-inflammatory effects by inhibiting NF-κB signaling, and LE is proposed to be a useful therapeutic agent against contact dermatitis.

Clinical significance of the muscle-retracting sign during colorectal endoscopic submucosal dissection

Background and study aims: During colorectal endoscopic submucosal dissection (ESD), the feature of a muscle layer being pulled toward a neoplastic tumor is sometimes detected. We call this feature the muscle-retracting sign (MR sign). The aim of this study was to evaluate whether the MR sign is associated with particular types of neoplastic lesions and whether it has any clinical significance for ESD sessions. Patients and methods: A total of 329 patients underwent ESD for 357 colorectal neoplasms. The frequency of positivity for the MR sign was evaluated in different morphologic and histopathologic types of neoplasm. The success rate of complete resection and the incidence of complications were also evaluated according to whether lesions were positive or negative for the MR sign. Results: The rates of positivity for the MR sign in the various lesion types were as follows: laterally spreading tumor – granular nodular mixed type (LST-G-M), 9.6 %; laterally spreading tumor – granular homogeneous type (LST-G-H) and laterally spreading tumor – nongranular type (LST-NG), 0 %; sessile type, 41.2 %. The resection rate was 100 % (329 /329) in lesions negative for the MR sign; however, it was 64.3 % (18 /28) in lesions positive for the MR sign, which was significantly lower (P < 0.001). Conclusions: The MR sign was present only in some protruding lesions, and more importantly, it was associated with a high risk of incomplete tumor removal by ESD. Our data indicate that lesions positive for the MR sign lesions should be dissected with great caution; alternatively, based on the features of the individual case, a switch to surgery should be considered for the benefit of the patient.