Background & Aims Altered gut microbiota is implicated in development of colorectal cancer (CRC). Some intestinal bacteria have been reported to potentiate intestinal carcinogenesis by producing genotoxins, altering the immune response and intestinal microenvironment, and activating oncogenic signaling pathways. We investigated whether stool from patients with CRC could directly induce colorectal carcinogenesis in mice. Methods We obtained stored stool samples from participants in a metagenome study performed in Hong Kong. Conventional (male C57BL/6) mice were given azoxymethane to induce colon neoplasia after receiving a course of antibiotics in drinking water. Mice were gavaged twice weekly with stool from 5 patients with CRC or 5 healthy individuals (controls) for 5 weeks. Germ-free C57BL/6 mice were gavaged once with stool from 5 patients with CRC or 5 controls. We collected intestinal tissues from mice and performed histology, immunohistochemistry, expression microarray, quantitative polymerase chain reaction, immunoblot, and flow cytometry analyses. We performed 16S ribosomal RNA gene sequencing analysis of feces from mice. Results Significantly higher proportions of conventional mice fed with stool from individuals with CRC than control stool developed high-grade dysplasia (P < .05) and macroscopic polyps (P < .01). We observed a higher proportion of proliferating (Ki-67-positive) cells in colons of germ-free mice fed with stool from patients with CRC vs those fed with stool from controls (P < .05). Feces from germ-free and conventional mice fed with stool from patients with CRC vs controls contained different microbial compositions, with lower richness in mice fed with stool from patients with CRC. Intestines collected from conventional and germ-free mice fed with stool from patients with CRC had increased expression of cytokines that modulate inflammation, including C-X-C motif chemokine receptor 1, C-X-C motif chemokine receptor 2, interleukin 17A (IL17A), IL22, and IL23A. Intestines from conventional and germ-free mice fed with stool from patients with CRC contained higher proportions of T-helper 1 (Th1) cells (2.25% vs 0.44%) and Th17 cells (2.08% vs 0.31%) (P < .05 for each) than mice fed with stool from controls. Real-time polymerase chain reaction arrays revealed up-regulation of genes involved in cell proliferation, stemness, apoptosis, angiogenesis, invasiveness, and metastasis in mice fed with stool from patients with CRC. Conclusions We fed stool samples from patients with CRC and heathy individuals to germ-free mice and conventional mice with azoxymethane. We found stool from patients with CRC to increase the numbers of polyps, levels of intestinal dysplasia and proliferation, markers of inflammation, and proportions of Th1 and Th17 cells in colon, compared with stool from individuals without CRC. This study provides evidence that the fecal microbiota from patients with CRC can promote tumorigenesis in germ-free mice and mice given a carcinogen.

Proton pump inhibitors (PPIs) have been widely used to treat gastric acid-related diseases. They increase intragastric pH by blocking hydrogen/potassium (H⁺/K⁺) ATPases of gastric parietal cells. It is reported that nearly a quarter of adults use a PPI, of which, approximately 25%–70% are prescribed inappropriately.1 2 With the extensive use of PPIs, adverse responses have emerged, including an increased risk of intestinal infections, community-acquired pneumonia and impeded absorption of micronutrients.3–5 Although the relative risk is low, the high worldwide number of PPIs users means that absolute numbers with side effects are still high. These factors greatly contribute to the insecurity of prescribing physicians and the anxiety of patients.

Non-steroidal anti-inflammatory drugs (NSAIDs) can cause significant small bowel injuries. The role of gut microbiota in this NSAID-induced enteropathy is poorly understood. We studied the dynamic changes in gut microbiota following indomethacin administration in mice, and investigated the effects of these adaptive changes on subsequent NSAID-induced enteropathy. The changes in gut microbiota were studied using 16S rRNA sequencing, and the effects of such changes were investigated using antibiotics and a faecal transplantation model. After indomethacin treatment, significant adaptive changes in gut microbiota were observed, including increased abundance of Firmicutes and decreased abundance in that of Bacteroidetes. Depletion of gut microbiota with antibiotics led to a higher mortality (P = 0.0021) in mice compared to controls. Mice pre-transplanted with adaptively changed microbiota showed less small bowel injury and lower levels of pro-inflammatory cytokines when exposed to indomethacin. In summary, this study identifies adaptive changes in the gut microbiota upon indomethacin administration, which can in turn ameliorate further NSAID-induced injury. The heightened mortality with antibiotic depletion of the adaptively changed microbiota suggests its important role in protecting against such injury. This study provides insight for future efforts to target the microbiota as a therapeutic strategy.

Proton pump inhibitors (PPIs) are some of the most commonly prescribed drugs worldwide, but there are increasing concerns about digestive complications linked to PPIs. Next-generation sequencing studies have suggested that PPIs can significantly affect the composition of the gut microbiota, which in turn may substantially contribute to the development of these complications. Recently, emerging evidence has suggested that the translocation of oral microbes into the gut may be the primary mechanism underlying the alterations in the gut microbiota induced by PPIs in the presence of gastric acid suppression and impaired oral–gut barrier function. Moreover, the significance of oral–gut microbial translocation in health and disease conditions has gained increasing recognition. Consequently, it is imperative to enhance our understanding of the functions of the oral–gut microbiota axis in digestive disorders associated with PPI therapies. This review aims to summarize current research findings and further elucidate the contribution of the oral–gut microbiota to the pathogenesis of PPI-related digestive diseases. We aim to provide a theoretical foundation for future therapeutic and preventive strategies targeting PPI-related digestive complications through modulation of the oral–gut microbiota.

Background Some studies have shown that transjugular intrahepatic portosystemic shunt (TIPS) placement within 72 hours of admission improves survival in patients at high risk who present with acute variceal bleeding. However, the role of small-diameter covered TIPS in the secondary prophylaxis of variceal bleeding is still debatable. Purpose To compare the efficacy of 8-mm TIPS and endoscopic variceal ligation (EVL) plus propranolol in the prevention of variceal rebleeding among participants with advanced cirrhosis. Materials and Methods Between June 2015 and December 2018, participants admitted to the hospital for variceal bleeding were considered for enrollment in this randomized controlled trial (ClinicalTrials.gov). Participants with Child-Pugh class B or C cirrhosis were randomly assigned to receive an 8-mm covered TIPS or EVL and propranolol. The primary end point was recurrent variceal bleeding assessed using Kaplan-Meier curve analysis. Secondary end points included survival and overt hepatic encephalopathy (HE) assessed using Kaplan-Meier curve analysis. Results A total of 100 participants were enrolled, with 50 randomly assigned to the EVL plus propranolol group (median age, 54 years; IQR, 45-60 years; 29 male, 21 female) and 50 randomly assigned to the TIPS group (median age, 49 years; IQR, 43-56 years; 32 male, 18 female). The median follow-up period was 43.4 months. In the TIPS group, variceal rebleeding risk was reduced compared with variceal rebleeding risk in the EVL plus propranolol group (hazard ratio [HR], 0.31; 95% CI: 0.14, 0.69; P = .008), but the incidence of overt HE was higher in the TIPS group (30.0% vs 16.0%, P = .03). No differences in survival were observed between the two groups (1-year survival: TIPS, 98.0%; EVL plus propranolol, 92.0%; 3-year survival: TIPS, 94.0%; EVL plus propranolol, 85.7%; HR, 0.52; 95% CI: 0.19, 1.42; P = .22). Conclusion When compared with EVL plus propranolol, 8-mm TIPS led to reduced variceal rebleeding but did not impact overall survival in participants with Child-Pugh class B or C cirrhosis. Clinical trial registration no. NCT02477384 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Barth in this issue.

Background: Appendiceal bleeding is a rare cause of lower gastrointestinal bleeding, could be overlooked and diagnosed as obscure gastrointestinal bleeding. Due to limited real-world cases, the optimized management of appendiceal bleeding is unclear. We here shared our experiences in the past 20 years. Methods: A retrospective study was conducted at West China Hospital of Sichuan University. We reviewed data of 28,175 colonoscopies from 43,095 gastrointestinal bleeding patients between June 2003 and June 2023. Six patients diagnosed as appendiceal bleeding were included. Data including symptoms, laboratory tests, imaging results, endoscopic findings, treatment and prognosis were collected and analyzed. Results: Appendiceal bleeding accounts for 0.014% in gastrointestinal bleeding patients. Of the six patients, five were male, with a mean age of 48.5 years. Hematochezia was the most common symptom. The etiology included appendiceal angiodysplasia, appendicitis and appendectomy associated bleeding. Hemostasis was achieved by appendectomy, endoscopic therapy or medication according to different cases. One patient did not receive any treatment because of self-limiting bleeding. Conclusions: The diagnosis of appendiceal bleeding is challenging, repeated flushing during endoscopy is helpful. Appendectomy is the priority option for treatment as well as the etiology clarification, therapeutic endoscopy and medication could be considered case by case.