Yoshito Hayashi

CagA mediates epigenetic regulation to attenuate let-7 expression in Helicobacter pylori-related carcinogenesis

Objective MicroRNAs (miRNAs) act as tumour suppressor genes or oncogenes in the regulation of multiple carcinogenic processes. Aberrant miRNA expression is reported in Helicobacter pylori (H pylori)-related gastritis and gastric cancer. The cytotoxin-associated gene A (CagA) of H pylori has a pathophysiologically important role in gastric carcinogenesis. A study was undertaken to evaluate the effect of CagA on miRNA expression and its regulatory mechanism. Methods The effect of CagA on miRNA expression was assessed by comprehensive miRNA microarray. The mechanisms of the in vitro and in vivo effects of CagA on histone modification and DNA methylation and the involvement of CagA-dysregulated signal transduction on let-7, an important representative miRNA in gastric carcinogenesis, were investigated. Results In in vitro experiments, CagA significantly attenuated let-7 expression leading to Ras pathway activation. CagA enhanced c-myc, DNA methyltransferase 3B (DNMT3B) and Enhancer of Zeste homologue 2 (EZH2) expression and attenuated miR-26a and miR-101 expression, which resulted in the attenuation of let-7 expression by histone and DNA methylation. Experiments performed in CagA transgenic mice revealed that c-myc, EZH2 and DNMT3B expression were enhanced and let-7 expression was attenuated to induce Ras oncoprotein expression in the stomach, with no associated inflammation. Conclusions H pylori CagA induces aberrant epigenetic silencing of let-7 expression, leading to Ras upregulation.

Clinical outcomes of endoscopic submucosal dissection for superficial esophageal neoplasms: a multicenter retrospective cohort study

BACKGROUND AND STUDY AIMS The safety and efficacy of endoscopic submucosal dissection (ESD) for superficial esophageal neoplasms (SENs) have not been evaluated in a multicenter survey. The aim of this study was to investigate the clinical outcomes in a multicenter study that included municipal hospitals. PATIENTS AND METHODS Of 312 consecutive patients with 373 esophageal lesions treated by ESD at 11 hospitals from May 2005 to December 2012, a total of 368 SENs in 307 patients were retrospectively analyzed. RESULTS The median tumor size was 18 mm (range 2 - 85 mm). The median procedure time was 90 minutes (range 12 - 450 minutes). The en bloc resection and complete resection rates were 96.7 % (95 % confidence interval [CI] 94.4 % - 98.1 %) and 84.5 % (95 %CI 80.5 % - 87.8 %), respectively. Perforation (including mediastinal emphysema), postoperative pneumonia, bleeding, and esophageal stricture, occurred in 5.2 % (95 %CI 3.3 % - 7.9 %), 1.6 % (95 %CI 0.7 % - 3.5 %), 0 %, and 7.1 % (95 %CI 4.9 % - 10.2 %) of patients, respectively. All of these complications were cured conservatively. No procedure-related mortality occurred. Early treatment periods (odds ratio [OR] = 4.04; P < 0.01) and low volume institutions (OR = 3.03; P  = 0.045) were significantly independent risk factors for perforation. The circumference of the lesion was significantly associated with postoperative stricture (OR = 32.3; P < 0.01). The procedure times significantly decreased in the later period of the study (P < 0.01). Follow-up data (median 35 months; range 4 - 98 months) showed significant differences in overall survival (P = 0.03) and recurrence-free survival (P < 0.01) rates between patients with curative and noncurative resections. CONCLUSIONS Esophageal ESD has become feasible with acceptable complication risks and favorable long term outcomes.

Evaluation of the effects of combination therapy with branched-chain amino acid and zinc supplements on nitrogen metabolism in liver cirrhosis

Aim:  Disorders of protein metabolism in liver cirrhosis can affect prognosis or cause complications. Treatment with branched‐chain amino acid (BCAA) and zinc supplements has been shown to be effective against abnormal nitrogen metabolism in liver cirrhosis. There are, however, few studies on the effects of combining these supplements. In this study, the effect of combining BCAA and zinc treatment in cirrhosis was investigated.

Clinical features of post-polypectomy bleeding associated with heparin bridge therapy

 Heparin is given to patients undergoing colonoscopic polypectomy at high risk for thromboembolism. Little is known, however, about how heparin bridge therapy (HB) affects post‐polypectomy bleeding (PPB). The present study aimed to identify the clinical features of PPB associated with HB.

Integrated diagnostic strategy for the invasion depth of early gastric cancer by conventional endoscopy and EUS

BACKGROUND Although conventional endoscopy (CE) and EUS are considered useful for predicting the invasion depth (T-staging) in early gastric cancer (EGC), no effective diagnostic strategy has been established. OBJECTIVE To produce simple CE criteria and to elucidate an efficient diagnostic method by combining CE and EUS for accurate T-staging. DESIGN Single-center retrospective analysis. SETTING Academic university hospital. PATIENTS Consecutive patients with EGC from April 2007 to March 2012 who underwent CE and EUS before treatment. INTERVENTIONS Recorded endoscopic images were independently reviewed by 3 observers. The CE criteria for massive invasion were defined, and their utility and the additional value of EUS were assessed. MAIN OUTCOME MEASUREMENTS The accuracy of CE based on the criteria and the accuracy of EUS. RESULTS Two hundred thirty patients were enrolled: 195 with mucosal cancer or cancer in the submucosa less than 500 μm from the muscularis mucosae and 35 with invasive cancers. Multivariate analysis of the CE findings by 1 observer revealed that an irregular surface and a submucosal tumor-like marginal elevation were significantly associated with massive invasion. The simple CE criteria, consisting of those 2 features, had an overall accuracy of 73% to 82% and no significant differences in the diagnostic yield compared with EUS in all observers. CE accurately revealed mucosal cancer, and EUS efficiently salvaged the lesions that were over-diagnosed by CE. With our strategy, which involved the CE criteria and the optimal use of EUS, the comprehensive accuracy exceeded 85% in each observer. LIMITATIONS Retrospective, single-center study. CONCLUSIONS We demonstrated a practical strategy for T-staging in EGC using simple CE criteria and EUS.

Functional analysis of agalactosyl IgG in inflammatory bowel disease patients

Background: Agalactosyl immunoglobulin (Ig) G is increased in inflammatory bowel disease (IBD) similarly to rheumatoid arthritis (RA). The lectin complement pathway is shown to be activated through association of agalactosyl IgG with mannan‐binding lectin (MBL) in RA. Functional changes of IgG agalactosylation in IBD, however, have not yet been clarified. Methods: The ratio of the agalactosyl/non‐agalactosyl fraction in fucosylated IgG oligosaccharides (G0F/G2F) and serum MBL levels were analyzed in 59 patients with Crohns disease (CD), 64 ulcerative colitis (UC), and 39 healthy volunteers (HV). The MBL levels associated with serum IgG were analyzed by enzyme‐linked immunosorbent assay. MBL expression in the intestinal mucosa was analyzed by immunohistochemistry. Phagocytosis of sheep red blood cells (SRBC) reacted with either an agalactosyl or non‐agalactosyl SRBC‐specific IgG antibody was determined by flow cytometry. Results: The serum MBL levels were not significantly different among CD, UC, or HV. In patients with CD, the serum MBL levels were negatively correlated with the Crohns Disease Activity Index (CDAI). The levels of MBL associated with agalactosyl IgG were not different from those associated with non‐agalactosyl IgG. Immunoreactivity to MBL was less in the inflamed mucosa compared with the noninflamed mucosa. Phagocytic activity of SRBC was significantly higher in the presence of agalactosyl IgG compared to non‐agalactosyl IgG. Conclusions: Agalactosyl IgG oligosaccharides enhanced antibody‐dependent phagocytosis in vitro but did not activate the lectin complement pathway. Oligosaccharide alterations of IgG are not only a marker of IBD but also functionally modulate the immune function of IBD. (Inflamm Bowel Dis 2010;)

Activation of the Mitochondrial Apoptotic Pathway Produces Reactive Oxygen Species and Oxidative Damage in Hepatocytes That Contribute to Liver Tumorigenesis

Chronic hepatitis, including viral hepatitis and steatihepatitis, is a well-known high-risk condition for hepatocellular carcinoma. We previously reported that continuous hepatocyte apoptosis drives liver tumors in hepatocyte-specific Bcl-xL or Mcl-1 knockout mice. In this study, we further examine the underlying cellular mechanisms of generating tumors in apoptosis-prone liver. In cultured hepatocytes, the administration of ABT-737, a Bcl-xL/-2/-w inhibitor, led to production of reactive oxygen species (ROS) as well as activation of caspases. Mitochondria isolated from murine liver, upon administration of truncated-Bid, a proapoptotic Bcl-2 family protein, released cytochrome c and produced ROS, which was dependent on mitochondrial respiration. Hepatic apoptosis, regeneration, accumulation of oxidative damages, and tumorigenesis observed in hepatocyte-specific Mcl-1 knockout mice were substantially attenuated by further deficiency of Bax or Bid, suggesting that a balance of mitochondrial Bcl-2 family proteins governs generation of oxidative stress and other pathologies. Whole-exome sequencing clarified that C>A/G>T transversion, which is often caused by oxidative DNA damage in proliferating cells, was a frequently observed mutation pattern in liver tumors of Mcl-1 knockout mice. The administration of antioxidant L-N-acetylcysteine did not affect apoptosis, compensatory regeneration, or fibrotic responses but significantly reduced oxidative DNA damage and incidence and multiplicity of live tumors in Mcl-1 knockout mice. In conclusion, activation of the mitochondrial apoptotic pathway in hepatocytes accumulates intracellular oxidative damages, leading to liver tumorigenesis, independently of liver regeneration or fibrosis. This study supports a concept that antioxidant therapy may be useful for suppressing liver carcinogenesis in patients with chronic liver disease. Cancer Prev Res; 8(8); 693–701. ©2015 AACR.

Evaluation of Endoscopic Ultrasound Image Quality Is Necessary in Endosonographic Assessment of Early Gastric Cancer Invasion Depth

We evaluated whether endoscopic ultrasonography (EUS) image quality affects the accuracy of diagnosing the vertical invasion depth of early gastric cancer (EGC). A total of 75 lesions in 75 patients suspected of having EGC were enrolled. All patients underwent EUS examination. Findings of EUS were compared with histopathologic results. We evaluated the effect of the following clinicopathologic factors: location, diameter, surface pattern, concomitant ulceration, histology type, and EUS image quality score. EUS image quality was scored based on detection repeatability, appropriate probe placement, and clarity of the five gastric wall layers including the lesion. Sixty-three lesions (84%) were pathologically mucosal and 12 lesions (16%) were submucosal cancer. Overall accuracy was 82.7%. Significantly more lesions in the upper and middle portions of the stomach were incorrectly diagnosed than in the lower portion (P = 0.0019). Lesion diameter was significantly larger among incorrectly diagnosed lesions (P = 0.0257). Low-quality images were significantly more often associated with incorrectly diagnosed lesions than with correctly diagnosed lesions (P = 0.0001). Multivariate analysis revealed that EUS image quality was associated with EUS staging accuracy (odds ratio, 21.8; 95% confidence interval, 4.5–137.6). Low-quality EUS images led to an incorrect diagnosis of invasion depth of EGC, independent of tumor location or size.

Choroidal and cutaneous metastasis from gastric adenocarcinoma

Choroidal or cutaneous metastasis of gastric cancer is rare. Gastrointestinal cancer was found in only 4% in patients with uveal metastasis. Choroidal metastasis from gastric cancer was reported in two cases in earlier literature. The frequency of gastric cancer as a primary lesion was 6% in cutaneous metastasis of men, and cutaneous metastasis occurs in 0.8% of all gastric cancers. We report a patient with gastric adenocarcinoma who presented with visual disorder in his left eye and skin pain on his head as his initial symptoms. These symptoms were diagnosed to be caused by choroidal and cutaneous metastasis of gastric adenocarcinoma. Two cycles of chemotherapy consisted of oral S-1 and intravenous cisplatin (SPIRITS regimen); this was markedly effective to reduce the primary gastric lesion and almost all the metastatic lesions.

Indigo Naturalis ameliorates murine dextran sodium sulfate-induced colitis via aryl hydrocarbon receptor activation.

BackgroundIndigo Naturalis (IN) is used as a traditional herbal medicine for ulcerative colitis (UC). However, the mechanisms of action of IN have not been clarified. We aimed to evaluate the efficacy of IN for ameliorating colonic inflammation. We further investigated the mechanisms of action of IN.MethodsColitis severity was assessed in dextran sodium sulfate-induced colitis and trinitrobenzene sulfonic acid-induced colitis models with or without the oral administration of IN or indigo, which is a known major component of IN. Colonic lamina propria (LP) mononuclear cells isolated from IN-treated mice were analyzed with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and flow cytometry. LP and splenic mononuclear cells cultured in vitro with IN or indigo were also analyzed. The role of the candidate receptor for indigo, the aryl hydrocarbon receptor (AhR), was analyzed using Ahr-deficient mice.ResultsColitis severity was significantly ameliorated in the IN and indigo treatment groups compared with the control group. The mRNA expression levels of interleukin (Il)-10 and Il-22 in the LP lymphocytes were increased by IN treatment. The treatment of splenocytes with IN or indigo increased the expression of anti-inflammatory cytokines and resulted in the expansion of IL-10-producing CD4+ T cells and IL-22-producing CD3−RORγt+ cells, but not CD4+Foxp3+ regulatory T cells. The amelioration of colitis by IN or indigo was abrogated in Ahr-deficient mice, in association with diminished regulatory cytokine production.ConclusionsIN and indigo ameliorated murine colitis through AhR signaling activation, suggesting that AhR could be a promising therapeutic target for UC.