Initial management for acute lower gastrointestinal bleeding

Acute lower gastrointestinal bleeding(LGIB) is a common indication for hospital admission. Patients with LGIB often experience persistent or recurrent bleeding and require blood transfusions and interventions, such as colonoscopic,radiological, and surgical treatments. Appropriate decision-making is needed to initially manage acute LGIB, including emergency hospitalization, timing of colonoscopy, and medication use. In this literature review, we summarize the evidence for initial management of acute LGIB. Assessing various clinical factors,including comorbidities, medication use, presenting symptoms, vital signs, and laboratory data is useful for risk stratification of severe LGIB, and for discriminating upper gastrointestinal bleeding. Early timing of colonoscopy had the possibility of improving identification of the bleeding source, and the rate of endoscopic intervention, compared with elective colonoscopy. Contrast-enhanced computed tomography before colonoscopy may help identify stigmata of recent hemorrhage on colonoscopy, particularly in patients who can be examined immediately after the last hematochezia. How to deal with nonsteroidal antiinflammatory drugs(NSAIDs) and antithrombotic agents after hemostasis should be carefully considered because of the risk of rebleeding and thromboembolic events. In general, aspirin as primary prophylaxis for cardiovascular events and NSAIDs were suggested to be discontinued after LGIB. Managing acute LGIB based on this information would improve clinical outcomes. Further investigations are needed to distinguish patients with LGIB who require early colonoscopy and hemostatic intervention.

Characteristics and predictors of gastric cancer after Helicobacter pylori eradication

Helicobacter pylori(H. pylori) eradication can reduce gastric cancer. However, gastric cancer still develops after eradication, and cases who received eradication therapy are increasing. In this study, we have reviewed the characteristics and predictors of primary gastric cancer developing after H. pylori eradication. In terms of the characteristics, endoscopic, histologic, and molecular characteristics are reported. Endoscopically, gastric cancer after eradication is often depressedtype and shows a gastritis-like appearance, which sometimes makes the diagnosis difficult. Histologically, most gastric cancer after eradication is intestinal type, and non-neoplastic epithelium, also called epithelium with low-grade atypia, is frequently seen over the tumor, which is presumably the cause of the endoscopic gastritis-like appearance. As for molecular characteristics, some markers, such as Ki67, MUC2, and Wnt5a expression, are lower in cancer from patients in whom H. pylori has been eradicated. In terms of predictors, several Japanese studies have reported that severe endoscopic atrophy at eradication is a risk factor for gastric cancer development. Histologic intestinal metaplasia, especially in the corpus, and long-term use of proton pump inhibitors, are also reported as risk factors for gastric cancer after H. pylori eradication. These studies on the characteristics and predictors of gastric cancer development will become the cornerstone for establishing a novel surveillance program based on the gastric cancer risk stratification specific to H. pylori-eradicated patients.

NF-κB and ERK-signaling pathways contribute to the gene expression induced by cag PAI-positive-Helicobacter pylori infection

AIM: To elucidate the sequential gene expression profile in AGS cells co-cultured with wild-type Hellcobacter pylori (Hpylon) as a model of H pylori-infected gastric epithelium, and to further examine the contribution of cag-pathogenicity islands (cagPAI)-coding type Ⅳ secretion system and the two pathways, nuclear factor kappa B (NF-κB) and extracellular signal-regulated kinases (ERK) on wild-type H pylori-induced gene expression. METHODS: Gene expression profiles induced by H pylori were evaluated in AGS gastric epithelial cells using cDNA microarray, which were present in the 4 600 independent clones picked up from the human gastric tissue. We also analyzed the contribution of NF-κB and ERK signaling on H pylori-induced gene expression by using inhibitors of specific signal pathways. The isogenic mutant with disrupted capE (△cagE) was used to elucidate the role of capPAI-encoding type Ⅳ secretion system in the gene expression profile. RESULTS: According to the expression profile, the genes were classified into four clusters. Among them, the clusters characterized by continuous upregulation were most conspicuous, and it contained many signal transducer activity-associated genes. The role of cagPAI on cultured cells was also investigated using isogenic mutant cagE, which carries non-functional cagPAI. Then the upregulation of more than 80% of the induced genes (476/566) was found to depend on cagPAI. Signal transducer pathway through NF-κB or ERK are the major pathways which are known to be activated by cagPAI-positive H pylori. The role of these pathways in the whole signal activation by cagPAI- positive H pylori was analyzed. The specific inhibitors against NF-κB or ERK pathway blocked the activation of gene expression in 65% (367/566) or 76% (429/566) of the genes whose activation appealed to depend on cagPAI. CONCLUSION: These results suggest that more than half of the genes induced by cagPAI-positive H pylori depend on NF-κB and ERK signaling activation, and these pathways may play a role in the gene expression induced by host-bacterial interaction which may associate with H pylori-related gastro-duodenal diseases.

Risk factors for small bowel angioectasia:The impact of visceral fat accumulation

AIM: To investigate visceral fat accumulation in association with the risk of small bowel angioectasia.METHODS: We retrospectively investigated 198 consecutive patients who underwent both capsule endoscopy and CT for investigation of obscure gastrointestinal bleeding(OGIB) from January 2009 to September 2013. The visceral fat area(VFA) and subcutaneous fat area were measured by CT, and information on comorbidities, body mass index, and medications was obtained from their medical records.Logistic regression analysis was used to evaluate associations.RESULTS: Capsule endoscopy revealed small bowel angioectasia in 18/198(9.1%) patients with OGIB.Compared to patients without small bowel angioectasia,those with small bowel angioectasia had a significantly higher VFA(96 ± 76.0 cm2 vs 63.4 ±51.5 cm2, P = 0.016) and a higher prevalence of liver cirrhosis(61% vs 22%, P < 0.001). The proportion of patients with chronic renal failure was higher in patients with small bowel angioectasia(22% vs 9%,P = 0.11). There were no significant differences in subcutaneous fat area or waist circumference. The prevalence of small bowel angioectasia progressively increased according to the VFA. Multivariate analysis showed that the VFA [odd ratio(OR) for each 10-cm2 increment = 1.1; [95% confidence interval(CI):1.02-1.19; P = 0.021] and liver cirrhosis(OR = 6.1,95%CI: 2.2-18.5; P < 0.001) were significant risk factors for small bowel angioectasia.CONCLUSION: VFA is positively associated with theprevalence of small bowel angioectasia, for which VFA and liver cirrhosis are independent risk factors in patients with OGIB.

Impact of fecal occult blood on obscure gastrointestinal bleeding:Observational study

AIM: To elucidate the association between small bowel diseases(SBDs) and positive fecal occult blood test(FOBT) in patients with obscure gastrointestinal bleeding(OGIB).METHODS: Between February 2008 and August 2013, 202 patients with OGIB who performed both capsule endoscopy(CE) and FOBT were enrolled(mean age; 63.6 ± 14.0 years, 118 males, 96 previous overt bleeding, 106 with occult bleeding). All patients underwent immunochemical FOBTs twice prior to CE. Three experienced endoscopists independently reviewed CE videos. All reviews and consensus meeting were conducted without any information on FOBT results. The prevalence of SBDs was compared between patients with positive and negative FOBT.RESULTS: CE revealed SBDs in 72 patients(36%). FOBT was positive in 100 patients(50%) and negative in 102(50%). The prevalence of SBDs was significantly higher in patients with positive FOBT than those with negative FOBT(46% vs 25%, P = 0.002). In particular, among patients with occult OGIB, the prevalence of SBDs was higher in positive FOBT group than negative FOBT group(45% vs 18%, P = 0.002). On the other hand, among patients with previous overt OGIB, there was no significant difference in the prevalence of SBDs between positive and negative FOBT group(47% vs 33%, P = 0.18). In disease specific analysis among patients with occult OGIB, the prevalence of ulcer and tumor were higher in positive FOBT group than negative FOBT group. In multivariate analysis, only positive FOBT was a predictive factors of SBDs in patients with OGIB(OR = 2.5, 95%CI: 1.4-4.6, P = 0.003). Furthermore, the trend was evidentam on g patients with occult OGIB who underwent FOBT on the same day or a day before CE. The prevalence of SBDs in positive vs negative FOBT group were 54% vs 13% in patients with occult OGIB who underwent FOBT on the same day or the day before CE(P = 0.001), while there was no significant difference between positive and negative FOBT group in those who underwent FOBT two or more days before CE(43% vs 25%, P = 0.20).CONCLUSION: The present study suggests that positive FOBT may be useful for predicting SBDs in patients with occult OGIB. Positive FOBT indicates higher likelihood of ulcers or tumors in patients with occult OGIB. Undergoing CE within a day after FOBT achieved a higher diagnostic yield for patients with occult OGIB.

Sessile serrated adenoma detection rate is correlated with adenoma detection rate

AIM To investigated the association between adenoma detection rate(ADR) and sessile serrated ADR(SSADR) and significant predictors for sessile serrated adenomas(SSA) detection.METHODS This study is a retrospective, single-center analysis. Total colonoscopies performed by the gastroenterologists at the University of Tokyo Hospital between January and December 2014 were retrospectively identified. Polyps were classified as low-grade or high-grade adenoma, cancer, SSA, or SSA with cytological dysplasia, and the prevalence of each type of polyp was investigated. Predictors of adenoma and SSA detection were examined using logistic generalized estimating equation models. The association between ADR and SSADR for each gastroenterologist was investigated by calculating a correlation coefficient weighted by the number of each gastroenterologist's examination.RESULTS A total of 3691 colonoscopies performed by 35 gastroenterologists were assessed. Overall, 978 (26.5%) low-and 84 (2.2%) high-grade adenomas, 81 (2.2%) cancers, 66 (1.8%) SSAs, and 2 (0.1%) SSAs with cytological dysplasia were detected. Overall ADR was 29.5%(men 33.2%, women 23.8%) and overall SSADR was 1.8%(men 1.7%, women 2.1%). In addition, 672 low-grade adenomas (68.8% of all the detected lowgrade adenomas), 58 (69.9%) high-grade adenomas, 29 (34.5%) cancers, 52 (78.8%) SSAs, and 2 (100%) SSAs with cytological dysplasia were found in the proximal colon. Adenoma detection was the only significant predictor of SSA detection (adjusted OR: 2.53, 95%CI: 1.53-4.20; P < 0.001). The correlation coefficient between ADR and SSADR weighted by the number of each gastroenterologist's examinations was 0.606(P < 0.001).CONCLUSION Our results demonstrated that ADR is correlated to SSADR. In addition, patients with adenomas had a higher prevalence of SSAs than those without adenomas.