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Brian E Lacy,1 David Rosenbaum,2 Susan Edelstein,2 Kenji Kozuka,2 Laura A Williams,2 David C Kunkel3 1Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL, USA; 2Ardelyx, Inc, Waltham, MA, USA; 3Division of Gastroenterology, University of California San Diego, La Jolla, CA, USACorrespondence: Brian E Lacy, Division of Gastroenterology and Hepatology, Mayo Clinic, Davis Building, 4500 San Pablo Road, Jacksonville, FL, 32224, USA, Tel +1 904-953-6319, Fax +1 904-953-7366, Email lacy.brian@mayo.eduAbstract: Increased intestinal permeability has been identified as one of the many pathophysiological factors associated with the development of irritable bowel syndrome (IBS), a common disorder of gut–brain interaction. The layer of epithelial cells that lines the intestine is permeable to a limited degree, and the amount of paracellular permeability is tightly controlled to enable the absorption of ions, nutrients, and water from the lumen. Increased intestinal permeability to macromolecules can be triggered by a variety of insults, including infections, toxins from food poisoning, or allergens, which in turn cause an inflammatory response and are associated with abdominal pain in patients with IBS. This review article discusses increased intestinal permeability in IBS, focusing on IBS with constipation (IBS-C) through the lens of a patient case with a reported prior diagnosis of “leaky gut syndrome” upon initial contact with a gastrointestinal specialist. We review advantages and disadvantages of several methods of measuring intestinal permeability in patients and discuss when measuring intestinal permeability is appropriate in the therapeutic journey of patients with IBS-C. Furthermore, we discuss a possible mechanism of restoring the intestinal barrier to its healthy state through altering intracellular pH by inhibiting sodium-hydrogen exchanger isoform 3 (NHE3). Tenapanor is a minimally absorbed, small-molecule inhibitor of NHE3 that has been approved by the US Food and Drug Administration for the treatment of IBS-C in adults. Preclinical studies showed that tenapanor may restore the intestinal barrier in IBS-C by affecting the conformation of tight junction proteins via NHE3 inhibition to block the paracellular transport of macromolecules from the intestinal lumen. Testing for increased permeability in patients with IBS-C who experience abdominal pain may help inform the choice of therapeutics and alter patients’ misconceptions about “leaky gut syndrome”.Keywords: tenapanor, abdominal pain, leaky gut, gut permeability, IBS-C, tight junction protein, transepithelial resistance

Prashant Singh,1 Gregory S Sayuk,2 David P Rosenbaum,3 Susan Edelstein,3 Kenji Kozuka,3 Lin Chang4 1Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; 2Department of Medicine, Washington University School of Medicine, St Louis, MO, USA; 3Ardelyx, Inc, Waltham, MA, USA; 4Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USACorrespondence: Prashant Singh, Department of Internal Medicine, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI, 48109, USA, Tel +1 734 647 9252, Fax +1 734 936 9849, Email singhpr@med.umich.eduBackground: Patients with irritable bowel syndrome with constipation (IBS-C) experience persistent abdominal pain, a common symptom leading to greater healthcare utilization and reports of treatment non-response. Clinically significant improvements in abdominal pain were observed in clinical trials of tenapanor, a first-in-class inhibitor of sodium/hydrogen exchanger isoform 3 (NHE3), for the treatment of IBS-C in adults.Aim: This narrative review reports the current knowledge about visceral hypersensitivity as a mechanism for abdominal pain in patients with IBS-C and explores the published evidence for hypothesized mechanisms by which tenapanor may reduce visceral hypersensitivity leading to the observed clinical response of decreased abdominal pain.Findings: Abdominal pain is experienced through activation and signaling of nociceptive dorsal root ganglia that innervate the gut. These sensory afferent neurons may become hypersensitized through signaling of transient receptor potential cation channel subfamily V member 1 (TRPV1), resulting in reduced action potential thresholds. TRPV1 signaling is also a key component of the proinflammatory cascade involving mast cell responses to macromolecule exposure following permeation through the intestinal epithelium. Indirect evidence of this pathway is supported by observations of higher pain in association with increased intestinal permeability in patients with IBS. Tenapanor reduces intestinal sodium absorption, leading to increased water retention in the intestinal lumen, thereby improving gastrointestinal motility. In animal models of visceral hypersensitivity, tenapanor normalized visceromotor responses and normalized TRPV1-mediated nociceptive signaling.Conclusion: By improving gastrointestinal motility, decreasing intestinal permeability and inflammation, and normalizing nociception through decreased TRPV1 signaling, tenapanor may reduce visceral hypersensitivity, leading to less abdominal pain in patients with IBS-C. Therapies that have demonstrated effects on visceral hypersensitivity may be the future direction for meaningful abdominal pain relief for patients with IBS-C.Keywords: IBS-C, NHE3, abdominal pain, TRPV1, sodium absorption, intestinal permeability

The schlieren photographs of in-cylinder processes in a spark-ignited premixed charge gasoline engine were observed via a transparent collimating cylinder and were presented in comparison with a pressure analysis. The schlieren photographs of the spark, the initial fame and the unburned gas ejection from the piston crevice, which is unable to be observed by direct photography, were clearly taken. It shows that the small difference in the initial combustion process among cycles is intensified by the movement of the piston during the expansion stroke. Finally, this difference appears as the cycle by cycle variation in the pressure and the rate of heat release. The observed flame size increased faster and was larger than the burned gas estimated from the pressure. The difference between them is large enough and can not be explained without considering the mixing of burned and unburned gases inside the flame front. [DOI: 10.1115/1.1496774]

Because of increased risks of cardiovascular disease and death, patients with hyperphosphatemia receiving maintenance dialysis are advised to limit phosphorus consumption and are prescribed phosphate binders in an effort to better control serum phosphate concentrations. Because of large pill size, pill burden, and tolerability issues, phosphate binder adherence is relatively poor. On ingestion, phosphate is absorbed from the intestine via transcellular or paracellular transport. Data show that inhibiting sodium-hydrogen exchanger 3 modulates paracellular phosphate absorption (the predominant pathway in humans). Tenapanor is a first-in-class, minimally absorbed, phosphate absorption inhibitor that selectively inhibits sodium-hydrogen exchanger 3, with a mechanism distinct from, and complementary to, that of phosphate binders. In phase 3 and postregistrational studies, tenapanor conferred statistically significant and clinically meaningful reductions in serum phosphate in patients receiving maintenance dialysis with hyperphosphatemia. Here, we review the available preclinical and clinical data on the effects of tenapanor on controlling intestinal phosphate absorption., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Photochromism through excited-state intermolecular proton transfer (ESInterPT) processes based on keto-enol tautomerization was found in phenazine-2,3-diol PD1 and its monoalkoxy derivative PD2 in a glassy matrix at 77 K: the colorless solutions of enol forms PD1-E and PD2-E at 298 K transformed into orange-colored solutions of keto forms PD1-K and PD2-K upon photoirradiation ( λ = 385 nm) at 77 K. Furthermore, this report is the first to achieve the single-crystal X-ray structural analyses of phenazine-2,3-diol PD1 and its monoalkoxy derivative PD2, since the report on the synthesis of PD1 70 years ago. Indeed, it was found that PD1 and PD2 molecules exist in the keto form (PD1-K) and the enol form (PD2-E), respectively, in the crystal, and the neighboring PD1-K and PD2-E molecules are linked by one-dimensional intermolecular NH⋯O and OH⋯N hydrogen bonding, respectively. The fact suggests strongly that for PD1 and PD2, the formation of continuous intermolecular hydrogen bonding in aggregates such as in a glassy matrix at 77 K is involved in the keto-enol tautomerization of phenazine-2,3-diol derivatives based on ESInterPT. More interestingly, the color and the photoabsorption spectrum of the solids obtained by sublimation of crystals of PD2-E are similar to those for the crystals of PD1-K, indicating that the PD2 molecule exists in the keto form (PD2-K) in the solid of the sublimate. Therefore, this study provides a valuable insight for a greater understanding of the keto-enol tautomerization of diazaacene-diol derivatives and their photophysical properties in the solution and in the solid state.

The pathogenesis of irritable bowel syndrome (IBS) is multifactorial, characterized in part by increased intestinal permeability, and visceral hypersensitivity. Increased permeability is associated with IBS severity and abdominal pain. Tenapanor is FDA-approved for the treatment of IBS with constipation (IBS-C) and has demonstrated improvements in bowel motility and a reduction in IBS-related pain; however, the mechanism by which tenapanor mediates these functions remains unclear. Here, the effects of tenapanor on colonic pain signaling and intestinal permeability were assessed through behavioral, electrophysiological, and cell culture experiments. Intestinal motility studies in rats and humans demonstrated that tenapanor increased luminal sodium and water retention and gastrointestinal transit versus placebo. A significantly reduced visceral motor reflex (VMR) to colonic distension was observed with tenapanor treatment versus vehicle in two rat models of visceral hypersensitivity (neonatal acetic acid sensitization and partial restraint stress; both P < 0.05), returning VMR responses to that of nonsensitized controls. Whole cell voltage patch-clamp recordings of retrogradely labeled colonic dorsal root ganglia (DRG) neurons from sensitized rats found that tenapanor significantly reduced DRG neuron hyperexcitability to capsaicin versus vehicle ( P < 0.05), an effect not mediated by epithelial cell secretions. Tenapanor also attenuated increases in intestinal permeability in human colon monolayer cultures caused by incubation with proinflammatory cytokines ( P < 0.001) or fecal supernatants from patients with IBS-C ( P < 0.005). These results support a model in which tenapanor reduces IBS-related pain by strengthening the intestinal barrier, thereby decreasing permeability to macromolecules and antigens and reducing DRG-mediated pain signaling. NEW & NOTEWORTHY A series of nonclinical experiments support the theory that tenapanor inhibits IBS-C-related pain by strengthening the intestinal barrier. Tenapanor treatment reduced visceral motor responses to nonsensitized levels in two rat models of hypersensitivity and reduced responses to capsaicin in sensitized colonic nociceptive dorsal root ganglia neurons. Intestinal permeability experiments in human colon monolayer cultures found that tenapanor attenuates increases in permeability induced by either inflammatory cytokines or fecal supernatants from patients with IBS-C.

Objectives: No protocol for esophagogastroduodenoscopic examination of the duodenum has been established. We examined the feasibility and ability to detect neoplasms of a novel duodenal examination protocol., Methods: This was a two-facility, prospective, observational study. Our protocol, the Seven Pictures Rule (7PR), requires pictures of the following seven locations: anterior and posterior to the bulb, area of and contralateral to the superior duodenal angle, area of and contralateral to the ampulla, and the transverse duodenum. The primary outcome was rate of completion of 7PR. Secondary outcomes were overall rates of detecting neoplasms, rates of detecting neoplasms for each location, examination time, and completion rates for standard or ultrathin endoscopes., Results: There were 1549 participants. The 7PR completion rate was 81.1% and the detection rates of overall neoplasms, adenomas, and carcinomas were 0.84%, 0.71%, and 0.06%, respectively. The area in which most neoplasms was detected was contralateral to the ampulla (69.2%), and the fewest the transverse duodenum (0%). Mean duration of duodenal examination was 53.1 s. Completion rates for standard vs. ultrathin were 84.4% (1077/1276) vs. 65.6% (179/273) (P < 0.01), respectively., Conclusions: Seven Pictures Rule is acceptable for duodenal examination and a potential quality indicator., (© 2023 Japan Gastroenterological Endoscopy Society.)

Background & Aims: Reported rates of delayed bleeding (DB) after endoscopic resection using direct oral anticoagulants (DOACs) are high and heterogeneous. This large-scale multicenter study analyzed cases of DB after colorectal endoscopic submucosal dissection related to various types of DOACs in Japan (the ABCD-J study) with those associated with warfarin., Methods: We retrospectively reviewed 1019 lesions in patients treated with DOACs and 459 lesions in patients treated with warfarin among 34,455 endoscopic submucosal dissection cases from 47 Japanese institutions between 2012 and 2021. The DB rate (DBR) with each DOAC was compared with that with warfarin. Risk factors for DB in patients treated with DOACs or warfarin were also investigated., Results: The mean tumor sizes in the DOAC and warfarin groups were 29.6 ± 14.0 and 30.3 ± 16.4 mm, respectively. In the DOAC group, the DBR with dabigatran (18.26%) was significantly higher than that with apixaban (10.08%, P = .029), edoxaban (7.73%, P = .001), and rivaroxaban (7.21%, P < .001). Only rivaroxaban showed a significantly lower DBR than warfarin (11.76%, P = .033). In the multivariate analysis, heparin bridging therapy (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.27-3.73, P = .005), rectal location (2.01, 1.28-3.16, P = .002), and procedure time ≥55 minutes (2.43, 1.49-3.95, P < .001) were significant risk factors for DB in the DOAC group. The DB risk in the DOAC group (OR, (95% CI)) was 2.13 (1.30-3.50) and 4.53 (2.52-8.15) for 1 and 2 significant risk factors, respectively., Conclusions: Dabigatran was associated with a higher DBR than other DOACs, and only rivaroxaban was associated with a significantly lower DBR than warfarin., (Copyright © 2024 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Competing Interests: The authors declare that they have no conflict of interest.

Competing Interests: The authors declare that they have no conflict of interest.

Aim: Phosphorus is a critical constituent of bone as a component of hydroxyapatite. Bone mineral content accrues rapidly early in life necessitating a positive phosphorus balance, which could be established by a combination of increased renal reabsorption and intestinal absorption. Intestinal absorption can occur via a transcellular pathway mediated by the apical sodium-phosphate cotransporter, Slc34a2/NaPiIIb or via the paracellular pathway. We sought to determine how young mammals increase dietary phosphorus absorption from the small intestine to establish a positive phosphorus balance, a prerequisite for rapid bone growth., Methods: The developmental expression profile of genes mediating phosphate absorption from the small intestine was determined in mice by qPCR and immunohistochemistry. Additionally, Ussing chamber studies were performed on small bowel of young (p7-p14) and older (8- to 17-week-old) mice to examine developmental changes in paracellular Pi permeability and transcellular Pi transport., Results: Blood and urinary Pi levels were higher in young mice. Intestinal paracellular phosphate permeability of young mice was significantly increased relative to older mice across all intestinal segments. NaPiIIb expression was markedly increased in juvenile mice, in comparison to adult animals. Consistent with this, young mice had increased transcellular phosphate flux across the jejunum and ileum relative to older animals. Moreover, transcellular phosphate transport was attenuated by the NaPiIIb inhibitor NTX1942 in the jejunum and ileum of young mice., Conclusion: Our results are consistent with young mice increasing phosphate absorption via increasing paracellular permeability and the NaPiIIb-mediated transcellular pathway., (© 2023 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.)

Sequence-based protein design approaches are being adopted to generate highly functional enzymes; however, screening the enzymes remains a time-consuming task. In this study, by analyzing the enzymatic properties of four ancestral meso-2,6-diaminopimelate dehydrogenases (AncDAPDHs), AncDAPDH-N1, -N2, -N3, and -N4, we attempted to define a new index parameter that is helpful for efficiently screening the enzymes. Biochemical and thermodynamic analyses indicated that only AncDAPDH-N4 exhibited greater thermal stability than and activity similar to those of native DAPDHs. Structural and sequence comparisons between DAPDH from Corynebacterium glutamicum (CgDAPDH) and the AncDAPDHs suggested that "quality of mutations" is a potential index parameter. In fact, the mutations introduced from CgDAPDH to AncDAPDH-N4 correlated highly with the mutations accumulated during the evolution process from mesophiles to thermophiles. These results suggest that, although there are several exceptions, the correlation coefficient can be used as an index parameter for screening high-functioning enzymes from sequence data., (© 2023 Wiley-VCH GmbH.)

Esophagogastroduodenoscopy (EGD) is an aerosol-generating procedure. A major challenge in the COVID-19 era is how to prevent the spread of aerosols and droplets in endoscopic units. We evaluated the effectiveness of an extraoral suction device in preventing indoor aerosol diffusion and droplet exposure for examiners. The study involved 61 patients who underwent EGD at our institution from 1 February to 31 March 2022. To determine whether aerosol spread increases before or after EGD examination with an extraoral suction device located in front of the patient's mouth, aerosols of 0.3, 0.5, 1, 3, 5, and 10 μm were measured with a handheld particle counter. The degree of contamination of the plastic gowns on the examiners was assessed using the rapid adenosine triphosphate test. The extraoral suction device significantly reduced the diffusion of large particles (3, 5, and 10 μm) after finishing the EGD examination. However, the diffusion of small particles (0.3 and 0.5 μm) was significantly increased. This extraoral suction device was effective in reducing large particle diffusion during EGD examination but was limited for minimizing small particle diffusion or droplet exposure to the examiner.

Background and Aim: To evaluate the efficacy and safety of a grasping-type knife, called Clutch Cutter (CC), for colorectal endoscopic submucosal dissection (C-ESD)., Methods: This was a randomized prospective study. Patients who underwent C-ESD for colorectal neoplasms >20 mm and <50 mm in size were enrolled, dividing into two groups: ESD using needle type of dual knife alone (D-group) and circumferential incision using dual knife followed by submucosal dissection using CC (CC-group). The primary outcome was the self-completion rate. The secondary outcomes were intraoperative complication rate, procedure time, and en bloc resection rate., Results: A total of 45 patients were allocated to the D-group and 43 to the CC-group were allocated. The self-completion rate was higher in the CC-group (87% [39/45] vs. 98% [42/43]). All of the six patients with an incomplete procedure in the D-group were completely resected with CC use. The intraoperative complication rate was not significant in either group (D vs. CC: 2% vs. 0%). The mean procedure time was significantly shorter in the D-group than that in the CC-group (62.0 vs. 81.1 min; p = 0.0036). The en bloc resection rate was 100% in the D-group and 98% in the CC-group., Conclusions: While dual knife use is superior to CC in terms of time efficiency, the use of CC may be a safe and efficacious option for achieving complete C-ESD.

Background: The management of delayed bleeding after gastric endoscopic submucosal dissection (ESD) is currently an important issue because of recent increases in the number of patients on antithrombotic therapy. Artificial ulcer closure has been shown to prevent delayed complications in the duodenum and colon. However, its effectiveness in cases involving the stomach remains unclear. In this study, we aimed to determine whether endoscopic closure reduces post-ESD bleeding in patients undergoing antithrombotic therapy., Methods: We retrospectively analyzed 114 patients who had undergone gastric ESD while on antithrombotic therapy. The patients were allocated to one of 2 groups: a closure group (n=44) and a non-closure group (n=70). Endoscopic closure had been performed using multiple hemoclips or using the endoscopic ligation with O-ring closure method after coagulation of exposed vessels on the artificial floor. Propensity score matching resulted in 32 pairs of patients (closure vs. non-closure 32:32). The primary outcome was post-ESD bleeding., Results: The post-ESD bleeding rate was significantly lower in the closure group (0%) than in the non-closure group (15.6%) (P=0.0264). There were no significant differences between the 2 groups regarding white blood cell count, C-reactive protein, maximum body temperature, or scores on a verbal rating scale that assesses the degree of abdominal pain., Conclusion: Endoscopic closure may contribute to decreasing the incidence of post-ESD gastric bleeding in patients undergoing antithrombotic therapy., Competing Interests: Conflict of Interest: None, (Copyright: © Hellenic Society of Gastroenterology.)

Background: The recently developed endoscopic full-thickness resection technique requires reliable closure. The main closure methods are the purse-string suture (PSS) technique and over-the-scope clip (OTSC) technique; however, basic data on the closure strength of each technique are lacking. This study was performed to compare the closure strengths of these two methods in an ex vivo porcine model., Methods: In the traction test, a virtual 5-cm full-thickness closure line was closed by the following six methods three times each: conventional hemoclips, mucosal PSS, seromuscular PSS, mucosal OTSC, seromuscular OTSC, and surgical suture. The primary endpoint was the tension at the starting point of dehiscence, measured in Newtons (N) by an automatic traction machine. In the leak test, a 15-mm gastric full-thickness defect was closed by PSS or OTSC six times each, and the closed stomach was then pressurized in a water container. The primary endpoint was the leak pressure when air bubbles appeared. The secondary endpoints were the procedure time and presence of complete inverted closure., Results: The mean tension was 2.16, 3.68, 5.15, 18.30, 19.30, and 62.40 N for conventional hemoclips, mucosal PSS, seromuscular PSS, mucosal OTSC, seromuscular OTSC, and surgical suture, respectively. Complete inverted closure was observed for seromuscular PSS, seromuscular OTSC, and surgical suture. The mean leak pressure was 13.7 and 24.8 mmHg in the PSS and OTSC group, respectively (P < 0.01). The mean procedure time was 541 and 169 s in the PSS and OTSC group, respectively (P < 0.01). Complete inverted closure was observed in OTSC alone., Conclusion: The OTSC, which allows complete inverted closure, showed greater closure strength than PSS. Considering the size limitation suitable for single OTSC, a therapeutic strategy for closing the larger size is further warranted., (© 2023. The Author(s).)

Introduction: Mucosal defect closure after colorectal endoscopic submucosal dissection (ESD) may prevent post-ESD adverse events. Delayed bleeding is a particular concern in the rectum due to the presence of numerous blood vessels. However, rectal defect closure often fails due to the thick rectal wall. This study aimed to examine the feasibility of our newly developed endoscopic ligation with O-ring closure (E-LOC) for defects after rectal ESD., Methods: This was a prospective observational study conducted at a single institution. After excluding 2 patients with tumors mostly extending into the anal canal, the study cohort comprised 30 consecutive patients who underwent ESD of rectal neoplasms between July 2020 and July 2021. E-LOC using an endoscopic variceal ligation device was performed for closing mucosal defects after rectal ESD. The primary outcome was the complete closure rate. The secondary outcomes were the delayed bleeding rate, E-LOC procedure time, sustained closure rates on postoperative day (POD) 3, and E-LOC-associated complications., Results: Complete closure of the defect (median defect size 29.0 mm) was successfully achieved in 24 cases (80%). Delayed bleeding occurred in one case with incomplete closure (3.3%). The median E-LOC procedure time was 25.5 min (interquartile range, 20.0-30.0 min). The sustained closure rates were 83.3% (20/24) on POD 3 in the 24 cases with complete closure. No E-LOC-associated complications occurred., Discussion/conclusions: E-LOC was feasible for defect closure after rectal ESD, and probably led to a decreased incidence of delayed bleeding., (© 2023 S. Karger AG, Basel.)

Glutamate decarboxylase (GAD) catalyses the decarboxylation of L-glutamate to gamma-aminobutyric acid (GABA). Improvement of the enzymatic properties of GAD is important for the low-cost synthesis of GABA. In this study, utilizing sequences of enzymes homologous with GAD from lactic acid bacteria, highly mutated GADs were designed using sequence-based protein design methods. Two mutated GADs, FcGAD and AncGAD, generated by full-consensus design and ancestral sequence reconstruction, had more desirable properties than native GADs. With respect to thermal stability, the half-life of the designed GADs was about 10 °C higher than that of native GAD. The productivity of FcGAD was considerably higher than those of known GADs; more than 250 mg/L of purified enzyme could be produced in the E. coli expression system. In a production test using 26.4 g of l-glutamate and 3.0 g of resting cells, 17.2 g of GABA could be prepared within one hour, without purification, in a one-pot synthesis., (© 2021 Wiley-VCH GmbH.)

We present herein the design, synthesis, and optimization of gut-restricted inhibitors of Na + /H + exchanger isoform 3 (NHE3). NHE3 is predominantly expressed in the kidney and gastrointestinal tract where it acts as the major absorptive sodium transporter. We desired minimally systemic agents that would block sodium absorption in the gastrointestinal tract but avoid exposure in the kidney. Starting with a relatively low-potency highly bioavailable hit compound ( 1 ), potent and minimally absorbed NHE3 inhibitors were designed, culminating with the discovery of tenapanor ( 28 ). Tenapanor has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of irritable bowel syndrome with constipation in adults., Competing Interests: The authors declare the following competing financial interest(s): J.W.J., M.R.L., L.H., K.K., M.N., and A.G.S. were employed by and own stock in Ardelyx, Inc. N.B., S.K.M., C.W.C., J.K., E.D.L., and D.C. were employed by Ardelyx, Inc., (© 2022 The Authors. Published by American Chemical Society.)

Background: The Over-The-Scope Clip (OTSC) can effectively treat refractory gastrointestinal diseases. However, most reports have focused on short-term effectiveness. We examined clinical outcomes of the deployed clips and long-term characteristics., Material and Methods: Of 47 patients with OTSC treatment, 35 with follow-up periods of ≥3 months were retrospectively examined. The indications were 11 bleedings, 17 perforations, and seven fistulas. The observation period was defined as medium-term (3 to <12 months) or long-term (≥12 months). The primary outcome was the clinical success rate without disease recurrence. The secondary outcomes were the complication rate, survival duration, and clip retention rate., Results: The medium- and long-term clinical success rates were 100% during the observation period (median, 44 months; range, 3-78 months). The complication rate was 2.9% ( n  = 1). The median survival time was 1,634 days for bleeding, 1,757 days for perforation, and 444 days for fistulas. The overall clip retention rates were 56.4%, 38.1%, 30.9%, and 25.9% after one, six, and 12 months and at the final follow-up, respectively. The average clip retention duration was 244 days in bleeding, 656 days in perforations, and 188 days in fistulas., Conclusions: Regardless of clip detachment, the OTSC can be effective in long-term.

Background: The management of postoperative bleeding, after gastric endoscopic submucosal dissection (ESD), has become particularly important because of the recent increase in antithrombotic use. Endoscopic shielding with polyglycolic acid (PGA) sheets has been shown to be effective. However, shrinkage and early displacement of the sheet remain challenges. This study aimed to determine the efficacy and safety of our developed method, named wafer paper and ring-mounted PGA sheet (WaRP)., Material and Methods: Twenty-four patients with antithrombotic uptake who underwent the WaRP method following gastric ESD were retrospectively examined. This involved the delivery of a PGA sheet wrapped in wafer paper with ring-thread, and its fixation on the gastric floor using hemoclips. The primary outcome was the technical success rate of the WaRP, and several secondary outcomes were evaluated., Results: The technical success rate of WaRP was 100%. The procedure lasted a mean of 10.5 min (SD 6.7 min). The prevalence of complete retention at follow-up endoscopy was 83.3% (20/24). There were no WaRP-associated complications, but post-ESD hemorrhage occurred in two patients undergoing hemodialysis (8.3%)., Conclusions: The WaRP method is a simple and reliable means of PGA sheet delivery and placement that reduces the incidence of post-ESD hemorrhage.

Competing Interests: The authors declare that they have no conflict of interest.