Neutrophil extracellular trap formation and its implications in nonsteroidal anti-inflammatory drug-induced small intestinal injury.

BACKGROUND AND AIM: Nonsteroidal anti-inflammatory drugs (NSAIDs) damage the small intestine via neutrophil infiltration driven by the mucosal invasion of enterobacteria. The antimicrobial function of neutrophils is partially dependent on neutrophil extracellular traps (NETs). Excessive NET formation has been associated with several inflammatory diseases. Here, we aimed to investigate the role of NETs in NSAID-induced small intestinal damage using human samples and an experimental mouse model. METHODS: Human small intestine specimens were obtained from NSAID users during double-balloon enteroscopy. Wild-type, protein arginine deiminase 4 (PAD4) knockout, and antibiotic-treated mice were administered indomethacin to induce small intestinal injury. The expression of NET-associated proteins, including PAD4, citrullinated histone H3 (CitH3), cell-free DNA, and myeloperoxidase (MPO), was evaluated. RESULTS: The double-positive stained area with CitH3 and MPO, which is specific for neutrophil-derived extracellular traps, was significantly high in the injured small intestinal mucosa of NSAID users. In a mouse model, small intestinal damage developed at 6 h after indomethacin administration, accompanied by increased mRNA levels of interleukin-1ß and keratinocyte chemoattractant and elevated NET-associated protein levels of PAD4, CitH3, and MPO in small intestine and serum levels of cell-free DNA. Both genetic deletion and pharmacological inhibition of PAD4 attenuated this damage by reducing the mRNA expression of inflammatory cytokines and NET-associated proteins. Furthermore, mice pretreated with antibiotics showed resistance to indomethacin-induced small intestinal damage, with less NET formation. CONCLUSION: These results suggest that NETs aggravate NSAID-induced small intestinal injury. Therefore, NET inhibition could be a potential treatment for NSAID-induced small intestinal injury.

Importance of Bowel Habits in Predicting Inadequate Bowel Preparation: A Prospective Observational Study.

OBJECTIVES: Inadequate bowel preparation (BP) negatively affects the efficacy and quality of colonoscopy. Although constipation has already been reported as one of the most important predictors of inadequate BP, there is limited information on the relation between inadequate BP and bowel habits including constipation-related symptoms, medications, and severity of constipation. METHODS: This single-center, prospective observational study was conducted between August 2019 and May 2020. All participants answered questionnaires regarding personal bowel habits and received low-volume polyethylene glycol plus ascorbic acid for outpatient colonoscopy. Severity of constipation was evaluated by constipation scoring system. Bowel preparation cleansing was evaluated using Boston Bowel Preparation Scale (BBPS). Potential predictors of inadequate BP were analyzed using multivariate logistic regression models. RESULTS: Overall, 1054 patients were enrolled, of which, 105 (10%) had inadequate BP (total BBPS ≤ 6 or any segmental BBPS < 2). The risk of inadequate BP increased with constipation severity (P = 0.01). Multivariate analysis showed that frequent straining (> 25% of defecations) (OR 2.09, 95% CI: 1.33-3.28) and chronic use of stimulant laxatives (OR 2.57, 95% CI: 1.59-4.17) were significant predictors of inadequate BP, among personal bowel habits. CONCLUSION: Frequent straining and chronic use of stimulant laxatives were predictors of inadequate BP. An intensified preparation regimen should be considered for severely constipated patients with straining and chronic use of stimulant laxatives.

Efficacy and tolerability of 1 L polyethylene glycol plus ascorbic acid with senna versus 2 L polyethylene glycol plus ascorbic acid for colonoscopic bowel preparation: Prospective, randomized, investigator-blinded trial.

OBJECTIVES: Low-volume polyethylene glycol plus ascorbic acid (PEG-Asc) reduces the dosage of colonoscopic bowel preparation (BP) solution, but is still poorly tolerated. Adding laxatives to the BP solution reduces the volume of fluid required, without affecting quality. This study aimed to compare 1 L PEG-Asc plus 24 mg senna (1L-PEG/AS) and conventional 2 L PEG-Asc (2L-PEG/A) regimens on BP quality and patient tolerability. METHODS: A single-center, randomized, investigator-blinded, noninferiority trial was performed between June and August 2022. Outpatients scheduled for colonoscopy were randomized (1:1) to the 1L-PEG/AS or 2L-PEG/A group. The Boston Bowel Preparation Scale (BBPS) was used to evaluate BP quality. Adverse events and tolerability were surveyed using questionnaires. RESULTS: Overall, 344 patients received 1L-PEG/AS or 2L-PEG/A regimens. The baseline characteristics and adverse events of the two groups were comparable. The 1L-PEG/AS group showed noninferior adequate BP rates compared with the 2L-PEG/A group (88% vs. 89%, P = 1.00); overall BBPS was 7.1 ± 1.5 and 7.2 ± 1.5, respectively (P = 0.39). Higher willingness to repeat the BP was observed in the 1L-PEG/AS group (85% vs. 62%, P < 0.01). CONCLUSIONS: The 1L-PEG/AS regimen was comparable to the 2L-PEG/A regimen in terms of BP adequacy, requiring lower BP solution volumes, with better patient tolerance. Thus, it may be a suitable alternative to the conventional BP solution for colonoscopy. The Japan Registry of Clinical Trials (jRCT1051220043).

Long-term rebleeding rate and predictive factors of rebleeding after capsule endoscopy in patients with obscure GI bleeding.

BACKGROUND AND AIMS: The incidence of rebleeding in obscure GI bleeding (OGIB) remains unclear. This study used capsule endoscopy (CE) to determine the long-term rebleeding rate and predictive factors for rebleeding in patients with OGIB. METHODS: This single-center, observational study enrolled consecutive patients with OGIB who underwent CE as the first small intestinal examination between March 2004 and December 2015 and were followed up through medical records or letters. RESULTS: Three hundred eighty-nine patients were included in the analysis. Survival curve analysis showed that the overall cumulative rebleeding rate in OGIB during the 5 years was 41.7%. Multivariate analysis using the Cox proportional hazards model revealed that overt OGIB (hazard ratio [HR], 2.017; 95% confidence interval [CI], 1.299-3.131; P = .002), anticoagulants (HR, 1.930; 95% CI, 1.093-3.410; P = .023), positive balloon-assisted enteroscopy findings after CE (HR, 2.927; 95% CI, 1.791-4.783; P < .001), and iron supplements without therapeutic intervention (HR, 2.202; 95% CI, 1.386-3.498; P = .001) were associated with rebleeding, whereas a higher minimum hemoglobin level (HR, .902; 95% CI, .834-.975; P = .009) and therapeutic intervention (HR, .288; 95% CI, .145-.570; P < .001) significantly reduced the risk of rebleeding. Among the Charlson Comorbidity Index components, liver cirrhosis was an independent predictor associated with rebleeding in patients with OGIB (HR, 4.362; 95% CI, 2.622-7.259; P < .001) and in patients with negative CE findings (HR, 8.961; 95% CI, 4.424-18.150; P < .001). CONCLUSIONS: Rebleeding is common during the long-term follow-up of patients with OGIB. Careful follow-up is required for patients with liver cirrhosis or previous massive bleeding.

Pirfenidone prevents esophageal stricture by inhibiting nucleotide binding oligomerization domain like receptor protein 3 inflammasome activation.

BACKGROUND AND AIM: Esophageal injury often results in a scar, leading to refractory strictures. The NLRP3 inflammasome activates caspase-1, causing the maturation of interleukin (IL)-1ß. Here, we aimed to investigate the preventive effect of pirfenidone (PFD), an antifibrotic drug, on esophageal stricture after ulcer healing and studied its mechanism by focusing on the activation of the NLRP3 inflammasome. METHODS: Esophageal ulcers were induced in rats via the local application of acetic acid in the serosa. PFD was intraperitoneally administered to the rats 3 days after ulcer induction. The effect of PFD on esophageal stricture after ulcer healing was assessed by esophagography on day 9. The protein levels of mature caspase-1 and IL-1ß were assessed by western blotting. RESULTS: The ulcers fully developed 3 days after induction and were almost scarred by day 9 with severe strictures. PFD promoted ulcer healing and attenuated fibrotic collagen in the submucosa by suppressing the increase in NLRP3, cleaved caspase-1, and mature IL-1ß expression, improving stricture rate (PFD vs vehicle = 55% vs 81%). Exogenous IL-1ß abolished the therapeutic effects of PFD on ulcer healing and stricture formation. Furthermore, NLRP3 and caspase-1 inhibitors mimicked the effects of PFD on ulcer healing and stricture formation, with suppression of the increase in cleaved caspase-1 and mature IL-1ß proteins and expression of fibrosis-related molecules including transforming growth factor (TGF)-ß1. CONCLUSION: The NLRP3 inflammasome promotes esophageal stricture formation following ulcer healing, and PFD exerts potential prophylactic activity against strictures, possibly via the inhibition of the NLRP3/IL-1ß/TGF-ß1 axis.

A Questionnaire-Based Survey on the Impact of the COVID-19 Pandemic on Gastrointestinal Endoscopy in Asia.

INTRODUCTION: The COVID-19 outbreak abruptly restricted gastrointestinal (GI) endoscopy services during the first wave of the pandemic. We aimed to assess the impact of COVID-19 on the practice of GI endoscopy in Asian countries. METHODS: This was an International Questionnaire-based Internet Survey conducted at multiple facilities by the International Gastrointestinal Consensus Symposium. A total of 166 respondents in Japan, China, Hong Kong, South Korea, Philippines, Thailand, Indonesia, and Singapore participated in this study. RESULTS: The volume of endoscopic screening or follow-up endoscopies and therapeutic endoscopies were markedly reduced during the first wave of the pandemic, which was mainly attributed to the decreased number of outpatients, cancellations by patients, and adherence to the guidelines of academic societies. The most common indications for GI endoscopy during the first wave were GI bleeding, cholangitis or obstructive jaundice, and a highly suspicious case of neoplasia. The most common GI symptoms of COVID-19 patients during the infected period included diarrhea, nausea, and vomiting. The pandemic exacerbated some GI diseases, such as functional dyspepsia and irritable bowel syndrome. There were cases with delayed diagnosis of cancers due to postponed endoscopic procedures, and the prescription of proton pump inhibitors/potassium-competitive acid blockers, steroids, immunosuppressive agents, and biologics was delayed or canceled. The personal protective equipment used during endoscopic procedures for high-risk patients were disposable gloves, disposable gowns, N95 or equivalent masks, and face shields. However, the devices on the patient side during endoscopic procedures included modified surgical masks, mouthpieces with filters, and disposable vinyl boxes or aerosol boxes covering the head. Furthermore, the time for education, basic research, clinical research, and daily clinical practice decreased during the first wave. CONCLUSION: This study demonstrated that the COVID-19 pandemic profoundly affected the method of performing GI endoscopy and medical treatment for patients with GI diseases in Asian countries.

[Current real-world treatments for Japanese patients with eosinophilic esophagitis].

A total of 306 patients with eosinophilic esophagitis (EoE) were analyzed at our department. Proton pump inhibitors or potassium-competitive acid blockers were used as the first-line treatment in 286 (93.5%) patients. Fifty-five (18.0%) patients received topical steroid swallowing therapy. During 17.7-month mean follow-up, 46.4% of the patients were followed-up with no medications, 37.3% of the patients received maintenance or on-demand therapy using acid-suppressive drugs, and 9.8% of the patients received maintenance therapy with steroid swallowing. The majority of patients with EoE were treated using a therapeutic strategy similar to that used for gastroesophageal reflux disease. However, some patients were refractory to the treatment. Current real-world treatment strategies for Japanese patients with EoE are clarified.

A 25 mg rectal dose of diclofenac for prevention of post-ERCP pancreatitis in elderly patients.

OBJECTIVES: A 50-100 mg rectal dose of diclofenac or indomethacin is recommended for prophylaxis of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP); however, limited data are available regarding the appropriate dose to prevent PEP in elderly patients. We aimed to evaluate the efficacy and safety of 25 mg diclofenac in preventing PEP in elderly patients. Material and methods: Overall, 276 patients with naive papilla, aged over 75 years, were included in the present study between April 2013 and March 2020. We retrospectively evaluated the risk of PEP in patients over 75 years, administered with or without 25 mg diclofenac 30 min before ERCP using inverse probability of treatment weighting (IPTW) analysis. Results: Patients were categorized into the diclofenac group (83 patients) or non-diclofenac group (193 patients). The incidence rate of PEP in the diclofenac group was significantly lower than that in the non-diclofenac group (4% vs. 14%, p = .01). Multivariate analysis revealed that 25 mg diclofenac was an independent protective factor against PEP in elderly patients aged over 75 years (odds ratio [OR] = 0.17; 95% confidence interval [CI] = 0.04-0.67; p = 0.01). This protective effect of diclofenac against PEP remained robust after IPTW analysis (OR = 0.11; 95% CI = 0.03-0.40; p = .001). No adverse events related to diclofenac were observed. Conclusion: Diclofenac (25 mg) was considered effective and safe for preventing PEP in elderly patients. Our results may provide a new strategy for preventing PEP in elderly patients.

Chronic constipation is negatively associated with colonic diverticula.

OBJECTIVES: Constipation has been considered the key risk factor for diverticulosis occurrence, but the underlying mechanism is unclear. We investigated the factors associated with diverticulosis, focusing on the association of constipation severity with the localization and number of diverticula. MATERIALS AND METHODS: We analyzed consecutive patients who underwent colonoscopy between March and December 2019. Chronic constipation was diagnosed as constipation meeting Rome IV criteria or as that requiring laxative therapy for more than 6 months. The degree of constipation was scored using the Constipation Scoring System (CSS). RESULTS: We assessed 1014 patients. Multivariate analysis revealed that age, alcohol consumption, and hypertension were positively associated with diverticulosis, whereas chronic constipation was negatively associated with diverticulosis (odds ratio [OR] = 0.74; 95% confidence interval [CI], 0.55-0.99). When assessed according to the location of diverticula, right-sided diverticula were significantly associated with a lower incidence of constipation (OR = 0.94; 95% CI, 0.89-0.98), whereas neither left-sided nor bilateral diverticula was associated with constipation. This negative association of diverticula with constipation was stronger in patients with a high CSS score. In stratified analysis, the number of diverticula decreased with increasing degree of constipation (p for trend <.01), and a high CSS score was associated with a decreased prevalence of ≥3 diverticula (OR = 0.64; 95% CI, 0.44-0.99). CONCLUSIONS: Chronic constipation was negatively associated with colonic diverticulosis. The association increased with the degree of constipation and was strong only in cases with right-sided diverticula and those with ≥3 diverticula.

Long-term persistence of gastric dysbiosis after eradication of Helicobacter pylori in patients who underwent endoscopic submucosal dissection for early gastric cancer.

BACKGROUND: Gastric microbiome, other than Helicobacter pylori, plays a role in the tumorigenesis of gastric cancer (GC). Patients who undergo endoscopic submucosal dissection for early GC have a high risk of developing metachronous GC even after successful eradication of H. pylori. Thus, we investigated the microbial profiles and associated changes in such patients after the eradication of H. pylori. METHODS: A total of 19 H. pylori-infected patients with early GC who were or to be treated by endoscopic resection, with paired biopsy samples at pre- and post-eradication therapy, were retrospectively enrolled. Ten H. pylori-negative patients were enrolled as controls. Biopsy samples were analyzed using 16S rRNA sequencing. RESULTS: H. pylori-positive patients exhibited low richness and evenness of bacteria with the deletion of several genera, including Blautia, Ralstonia, Faecalibacterium, Methylobacterium, and Megamonas. H. pylori eradication partially restored microbial diversity, as assessed during a median follow-up at 13 months after eradication therapy. However, post-eradication patients had less diversity than that in the controls and possessed a lower abundance of the five genera mentioned above. The eradication of H. pylori also altered the bacterial composition, but not to the same extent as that in controls. The microbial communities could be clustered into three separate groups: H. pylori-negative, pre-eradication, and post-eradication. CONCLUSION: Changes in dysbiosis may persist long after the eradication of H. pylori in patients with a history of GC. Dysbiosis may be involved in the development of both primary and metachronous GC after the eradication of H. pylori in such patients.

Role of nucleotide binding oligomerization domain-like receptor protein 3 inflammasome in stress-induced gastric injury.

BACKGROUND AND AIM: The inflammasomes promote pro-caspase-1 cleavage, leading to processing of pro-interleukin (IL)-1ß into its mature form. We investigated the role of the IL-1ß and nucleotide binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in gastric injury in mice receiving water-immersion restraint stress (WIRS), focusing on the cyclooxygenase (COX)-2/prostaglandin (PG) E2 axis. METHODS: To induce gastric injury, the mice were placed in a restraint cage and immersed in the water bath to the level of the xiphoid process. Protein levels of mature caspase-1 and IL-1ß were assessed by western blotting. RESULTS: Water-immersion restraint stress induced gastric injury with increase in IL-1ß expression by activation of NLRP3 inflammasome. Exogenous IL-1ß attenuated the injury, whereas anti-IL-1ß neutralizing antibody and IL-1ß receptor antibody aggravated it. NLRP3-/- and caspase-1-/- mice enhanced the injury with reducing of mature IL-1ß, and this aggravation was reduced by exogenous IL-1ß supplementation. Toll-like receptor 4-/- mice were hyporesponsive to WIRS in terms of mature IL-1ß production. Rabeprazole attenuated the injury with preventing inflammasome activation. WIRS injured the stomach with promotion of COX-2 mRNA and PGE2 production, and exogenous IL-1ß enhanced these molecules, while IL-1ß immunoneutralization exerted opposite effect. PGE2 supplementation abolished the hypersensitivity in NLRP3-/- and caspase-1-/- mice through negative regulation of inflammatory cytokines. CONCLUSION: These results suggest that NLRP3 inflammasome-derived IL-1ß plays a protective role in stress-induced gastric injury via activation of the COX-2/PGE2 axis. Toll-like receptor 4 signaling and gastric acid may be involved in NLRP3 inflammasome activation.

Effects of Colchicine on NSAID-Induced Severe Small Intestinal Damage: A Pilot Study.

BACKGROUND: We previously reported that nonsteroidal anti-inflammatory drugs (NSAIDs) induced small intestinal damage through nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome-dependent interleukin-1ß secretion in mice. Our further study demonstrated that colchicine, a therapeutic agent for gout, significantly suppressed NSAID-induced small intestinal damage by inhibiting NLRP3 inflammasome activation in mice. However, clinical efficacy of colchicine for NSAID-induced small intestinal damage has not been established. OBJECTIVES: We examined the clinical efficacy of colchicine in patients with NSAID-induced severe small intestinal damage as an animal-to-human translational research. METHODS: This is a single-center, single-arm, prospective pilot study. From February 2017 to March 2019, we performed video capsule endoscopy (VCE) to screen 10 patients who took NSAIDs continuously for more than 3 months, and 7 of those with severe small intestinal damage were enrolled. Participants were treated with oral colchicine 0.5 mg twice daily for 8 weeks and thereafter followed up with blood tests and VCE. RESULTS: After 8 weeks of colchicine treatment, complete healing was achieved in 4 patients (57.1%), and the median number of small erosions decreased significantly from 7.0 (range, 5.0-10.5) to 0.0 (range, 0.0-2.3) (p = 0.031). One patient withdrew due to diarrhea, and 5 patients revealed slightly elevated liver enzymes during the study. No other adverse events including changes in blood tests and clinical symptoms were observed. CONCLUSIONS: Colchicine treatment achieved a high rate of complete healing in patients with NSAID-induced severe small intestinal damage.

NOD-Like Receptor Family Pyrin Domain-Containing 3 Inflammasome Activation Exacerbates 5-Fluorouracil-Induced Small Intestinal Mucositis via Interleukin-1ß Activation.

BACKGROUND AND AIM: 5-Fluorouracil (5-FU) is an anticancer agent that induces intestinal mucositis, which causes diarrhea and dehydration. The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is responsible for inflammatory response activation via caspase-1 cleavage and subsequent interleukin-1ß (IL-1ß) and IL-18 activation and secretion. The objective of this study was to determine the role of the NLRP3 inflammasome in 5-FU-induced small intestinal mucositis. METHODS: Small intestinal mucositis was induced in wild-type, NLRP3-/-, and caspase-1-/- mice by intraperitoneal injection of 5-FU. Some mice received intraperitoneal injection of a caspase-1 inhibitor, recombinant IL-1ß or IL-18, or neutralizing antibody against IL-1ß. RESULTS: Mice treated with 5-FU developed small intestinal mucositis with diarrhea and body weight loss, characterized by a decrease in villus height and the villus height-to-crypt depth ratio. These histological changes peaked on day 3 and were accompanied by an increase in mRNA expression of NLRP3 and IL-1ß and protein expression of cleaved caspase-1 and mature IL-1ß. Mature IL-18 protein expression was not affected by 5-FU administration. NLRP3-/- mice exhibited less severe 5-FU-induced mucositis, and this phenotype was mimicked by genetic depletion or pharmacological inhibition of caspase-1. Small intestinal mucositis was aggravated by exogenous IL-1ß and neutralized by IL-1ß antibody treatment. Administration of exogenous IL-18 or anti-IL-18 antibody did not affect any parameters associated with mucositis. NLRP3, cleaved caspase-1, and IL-1ß were expressed by inflammatory cells (mainly macrophages) in the lamina propria and damaged epithelial cells. CONCLUSIONS: NLRP3 inflammasome activation may exacerbate 5-FU-induced small intestinal mucositis via IL-1ß maturation.

Misoprostol Heals Small Bowel Ulcers in Aspirin Users With Small Bowel Bleeding.

BACKGROUND & AIMS: There is no effective treatment for aspirin-induced small bowel ulcer bleeding. We performed a double-blind, randomized, placebo-controlled trial to determine whether misoprostol can heal small bowel ulcers in patients with small bowel bleeding who require continuous aspirin therapy. METHODS: We performed a prospective study of 84 aspirin users with small bowel bleeding who required continued aspirin therapy in Hong Kong and Japan. Patients with small bowel ulcers or multiple erosions, detected by capsule endoscopy, were randomly assigned to groups that received either misoprostol (200 µg, 4 times daily; n = 42) or placebo (n = 42) for 8 weeks. All patients continued taking aspirin (100 mg, once daily). The primary end point was complete ulcer healing at follow-up capsule endoscopy. Secondary end points included changes in hemoglobin level and number of ulcer/erosions from baseline. RESULTS: Complete healing of small bowel ulcers was observed in 12 patients in the misoprostol group (28.6%; 95% CI, 14.9%-42.2%) and 4 patients in the placebo group (9.5%; 95% CI, 0.6%-18.4%), for a difference in proportion of 19.0% (95% CI, 2.8%-35.3%; P = .026). The misoprostol group had a significantly greater mean increase in hemoglobin than the placebo group (mean difference, 0.70 mg/dL; 95% CI, 0.05-1.36; P = .035). The reduction in medium number of ulcers or erosions was significantly greater in the misoprostol group (from 6.5 [range, 1-85] to 2 [range, 0-25]) than in the placebo group (from 7 [range, 1-29] to 4 [range, 0-19] (P = .005). CONCLUSIONS: In a double-blind, randomized, placebo-controlled trial, we found misoprostol to be superior to placebo in promoting healing of small bowel ulcers among aspirin users complicated by small bowel ulcer bleeding who require continuous aspirin therapy. However, use of misoprostol alone would provide only limited protection against aspirin on the small bowel. ClinicalTrials.gov ID NCT01998776.