A Novel Retractable Robotic Device for Colorectal Endoscopic Submucosal Dissection.

Background/Aims: : Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). In this study, we developed a retractable robot-assisted traction device and evaluated its performance in colorectal ESD. Methods: : An experienced endoscopist performed ESD 18 times on an ex vivo porcine colon using the robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate. Results: : Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robot-assisted ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 minutes vs 34.3±8.3 minutes, p<0.05). The submucosal dissection speed was significantly faster in the RESD group than in the CESD group (36.8±9.2 mm2/min vs 18.1±4.7 mm2/min, p<0.05). The blind dissection rate was also significantly lower in the RESD group (12.8%±3.4% vs 35.1%±3.9%, p<0.05). In an in vivo porcine feasibility study, the robotic device was attached to a colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed. Conclusions: : The dissection speed and safety profile improved significantly with the retractable RESD. Thus, our robotic device has the potential to provide simple, effective, and safe multidirectional traction during colonic ESD.

Biphasic Regulation of Apoptosis Following Gastric Irreversible Electroporation Using Tissue Immunohistochemistry of Activated Caspase-3 with TUNEL Method.

The regulation of apoptosis is the primary goal of ablation therapy. Irreversible electroporation (IRE) is a promising non-thermal tissue ablation-based therapy that induces apoptosis by manipulating electrical conditions. This study aimed to investigate IRE-induced gastric tissue apoptosis in response to changes in the electric field intensity, followed by the repair process. Among the 52 rats used in this study, 24 were used to explore apoptosis, and 28 were used to study regeneration. The apoptosis-to-necrosis ratio of the electrical field strength was evaluated using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and caspase-3 immunohistochemistry. The size of IRE-induced ulcers in the gastric tissue continuously increased with increasing electrical intensity (r2 = 0.830, p < 0.001). The level of apoptosis gradually decreased after peaking at 200 V (1000 V/cm). The size of the 400 V-ablated ulcers continued to decrease, and they were not visible by day 14. The proliferation and migration of epithelial cells with fibroblasts were observed on day 3 and augmented on day 7 post-ablation. This investigation demonstrated the biphasic activation of apoptosis with respect to the electrical field strength. Visually and histologically, IRE-induced gastric ulcers demonstrated complete tissue regeneration after two weeks.

Application of natural orifice transluminal endoscopic surgery with ENDOCRAB system for stomach perforation model: ex vivo porcine study.

Iatrogenic stomach perforation is a detrimental, irreversible, and fatal condition. Traditional surgery and endoscopic suturing clips and devices have been introduced to seal holes and prevent sepsis and disease progression. However, the development of endoscopic devices for perforations remains challenging, with no standard device available. This study investigates the superficial layer approximation strengths of the newly designed ENDOCRAB system for gastric wall defects. Thirty porcine stomachs were prepared ex vivo for the perforation model and distributed equally into three groups: ENDOCRAB system, Through-the-Scope Clip (TTSC), and hand suturing (HS). Both ENDOCRAB and TTSC achieved mucosal-submucosal layer apposition, whereas HS allowed a full-thickness layer. Their air leakage pressure and procedural duration were measured. The analysis of air-leakage pressure demonstrated comparable suture strength between ENDOCRAB (118.5 ± 41.7 mmHg) and HS (127.4 ± 30.2 mmHg, P = 0.812), but inferior strength with TTSC (73.6 ± 21.6 mmHg, P = 0.012). HS achieved the shortest procedural duration, whereas ENDOCRAB and TTSC showed no significant differences. The ENDOCRAB system showed significantly greater strength than the TTSC, was comparable to HS in strength, and required a procedural duration similar to that of the TTSC. Furthermore, long-term in vivo experiments and histological evaluations are essential.

Robot-assisted gastric endoscopic submucosal dissection significantly improves procedure time at challenging dissection locations.

BACKGROUND: Endoscopic submucosal dissection (ESD) is the standard treatment for early malignant stomach lesions. However, this procedure is technically demanding and carries a high complication risk. The level of difficulty in performing ESD is influenced by the location of the lesion. In our study, we aimed to investigate and analyze the effectiveness of robot-assisted ESD for lesions situated in challenging locations within the stomach. METHODS: We developed a gastric simulator that could be used to implement various gastric ESD locations. An EndoGel (Sunarrow, Tokyo, Japan) was attached to the simulator for the dissection procedures. Robot-assisted or conventional ESD was performed at challenging or easy locations by two ESD-trainee endoscopists. RESULTS: The procedure time was remarkably shorter for robotic ESD than conventional dissection at challenging locations (6.2 vs. 10.2 min, P < 0.05), mainly due to faster dissection (220.3 vs. 101.9 mm2/min, P < 0.05). The blind dissection rate was significantly lower with robotic ESD than with the conventional method (17.6 vs. 35.2%, P < 0.05) at challenging locations. CONCLUSION: The procedure time was significantly shortened when robot-assisted gastric ESD procedures were performed at challenging locations. Therefore, our robotic device provides simple, effective, and safe multidirectional traction for endoscopic submucosal dissection at challenging locations, thereby reducing difficulty of the procedure.

Therapeutic Applications of Extracellular Vesicles in Inflammatory Bowel Disease.

The treatment landscape for inflammatory bowel disease (IBD) has undergone substantial advancements with the introduction of biologics. However, a considerable number of patients either show an immediate lack of response or lose responsiveness over time, necessitating the development of innovative and effective treatment approaches. Extracellular vesicles (EVs) are small lipid bilayer-enclosed structures that facilitate cell-to-cell molecular transfer and are integral to the pathogenesis of IBD. They play pivotal roles in maintaining the integrity of the intestinal epithelial barrier and the expulsion of cellular metabolites. The potential use of EVs as drug carriers or therapeutic agents has opened up a plethora of clinical applications. This review investigates the creation and content of EVs, their role in IBD development, and advances in their isolation and analytical techniques. Furthermore, the therapeutic promise they hold for IBD is explored, along with the latest research on their roles as IBD drug delivery systems.

Reappraisal of optimal reconstruction after distal gastrectomy - a study based on the KLASS-07 database.

BACKGROUNDS: This study aimed to compare the incidence of bile reflux, quality of life (QoL), and nutritional status among Billroth II (BII), Billroth II with Braun anastomosis (BII-B), and Roux-en-Y (RY) reconstruction after laparoscopic distal gastrectomy (LDG). MATERIALS AND METHODS: We reviewed the prospective data of 397 patients from a multicentre database who underwent LDG for gastric cancer between 2018 and 2020 at 20 tertiary teaching hospitals in Korea. Postoperative endoscopic findings, QoL surveys using the European Organization for Research and Treatment of Cancer questionnaire (C30 and STO22), and nutritional and surgical outcomes were compared among groups. RESULTS: In endoscopic findings, bile reflux was the lowest in the RY group ( n =67), followed by the BII-B ( n =183) and BII groups ( n =147) at 1 year (3.0 vs. 67.8 vs. 84.4%, all P <0.05). The anti-reflux capability of BII-B was statistically better than that of BII, but not as perfect as that of RY. From the perspective of QoL, BII-B was not inferior to RY, but better than BII reconstruction in causing fewer STO22 reflux symptoms at 6 and 12 months. However, only RY caused fewer C30 nausea symptoms than BII at 6 and 12 months, but not BII-B. Nutritional status and morbidities were similar among the three groups, and the operative time did not differ between the BII-B and RY groups. CONCLUSIONS: BII-B cannot substitute for RY in preventing bile reflux, shortening the operative time, or reducing morbidities. Regarding short-term QoL, BII-B was sufficient to reduce STO22 reflux symptoms but failed to reduce C30 nausea symptoms postoperatively.

Interobserver Variation of Bowel Preparation for Colonoscopy.

BACKGROUD/AIMS: Several bowel preparation scales have been developed, but they are variably validated to guide clinical practice. The aim of this study was to assess the interobserver reliability between internal and external endoscopists using the Harefield Cleaning Scale (HCS). METHODS: Data was collected from a study evaluating the efficacy of oral sulfate tablets in patients undergoing colonoscopy. The assessments of bowel cleansing were carried out by four internal endoscopists at the time of the procedure, and colonoscopy video recordings were reviewed independently by three external endoscopists. Interobserver reliability was quantified using Cohen's Kappa coefficient, and scores and grades of each segment were compared between internal and external endoscopist groups. RESULTS: Among 83 colonoscopy videos, interobserver reliability yielded a fair agreement between internal and external endoscopists, with a Cohen's Kappa coefficient of 0.39 (95% CI 0.08-0.70). Successful overall preparation rates (100% vs 98.8%) and high-quality preparation rates (88% vs 94%) were excellent and comparable between the two groups. In contrast, one case of unsuccessful cleansing (grade C) was documented, only in the external group. In addition, the interobserver reliability between internal and external endoscopists comparing each segmental score yielded a slight agreement in the descending colon (0.11, 95% CI - 0.02 to 0.23) and sigmoid colon (0.04, 95% CI - 0.18 to 0.26). DISCUSSION: Interobserver reliability between internal and external endoscopists using the HCS was fair. However, the HCS may be limited as a reliable scale for assessing bowel preparation quality in the left colon, where liquid is mainly retained in the left lateral position.

Assessment of efficacy and safety of advanced endoscopic irreversible electroporation catheter in the esophagus.

Nonthermal irreversible electroporation (NTIRE) is emerging as a promising tissue ablation technique. However, maintaining irreversible electroporation (IRE) electrodes against displacement during strong esophageal spasms remains an obstacle. The present study aimed to evaluate the efficacy and safety of newly designed balloon-type endoscopic IRE catheters. Six pigs were randomly allocated to each catheter group, and each pig was subjected to four ablations at alternating voltages of 1500 V and 2000 V. Esophagogastroscopy was performed during the IRE. The ability of balloon-type catheters to execute complete IRE with 40 pulses was assessed. The success rate was higher for the balloon-type catheter than that for the basket-type (12/12 [100%] vs. 2/12 [16.7%], p < 0.001). Following gross inspection and histologic analysis of the 1500-V vs. 2000-V balloon-type catheter revealed a larger mucosal damage area (105.3 mm2 vs. 140.8 mm2, p = 0.004) and greater damage depth (476 µm vs. 900 µm, p = 0.02). Histopathology of the ablated tissue revealed separated epithelium, inflamed lamina propria, congested muscularis mucosa, necrotized submucosa, and disorganized muscularis propria. Balloon-type catheters demonstrated efficacy, achieving full electrical pulse sequences under NTIRE conditions, and a safe histological profile below 2000 V (1274 V/cm). Optimal electrical conditions and electrode arrays pose ongoing challenges.

Exploring objective factors to predict successful outcomes after laparoscopic Nissen fundoplication.

BACKGROUND: Currently, the reported parameters that predict the resolution of symptoms after surgery are largely subjective and unreliable. Considering that fundoplication rebuilds the structural integrity of the lower esophageal sphincter (LES), the authors focused on searching for objective and quantitative predictors for the resolution of symptoms based on the anatomical issues and whether an antireflux barrier can be well established or not. MATERIALS AND METHODS: The authors reviewed the prospectively collected data of 266 patients with gastroesophageal reflux disease (GERD) who had undergone laparoscopic Nissen fundoplication (LNF). All patients were diagnosed with GERD using preoperative esophagogastroduodenoscopy, 24-h ambulatory esophageal pH monitoring, and high-resolution esophageal manometry. The patients received GERD symptom surveys using the validated Korean Antireflux Surgery Group questionnaire twice: preoperatively and 3 months after the surgery. RESULTS: After excluding patients with insufficient follow-up data, 152 patients were included in the analysis. Multivariate logistic regression analyses revealed that a longer length of the LES and lower BMI determined better resolution of typical symptoms after LNF (all P <0.05). Regarding atypical symptoms, higher resting pressure of LES and DeMeester score greater than or equal to 14.7 were associated with better resolution after the surgery (all P <0.05). After LNF, typical symptoms improved in 34 out of 37 patients (91.9%) with a length of LES >greater than .05 cm, BMI less than 23.67 kg/m 2 , and atypical symptoms were resolved in 16 out of 19 patients (84.2%) with resting pressure of LES greater than or equal to 19.65 mm Hg, DeMeester score greater than or equal to 14.7. CONCLUSION: These results show that the preoperative length and resting pressure of LES is important in the objective prediction of symptom improvement after LNF.

Propensity score-matched analysis of physician-controlled wire-guided cannulation as an effective technique against difficult cannulation in endoscopic retrograde cholangiopancreatography: A retrospective study.

BACKGROUND: Advanced endoscopic retrograde cholangiopancreatography (ERCP) cannulation strategies for difficult cases could replace conventional techniques, in which assistants control guidewires. We aimed to compare the safety and efficacy of a new salvage cannulation strategy, physician-controlled wire-guided cannulation (PCWGC), with those of a conventional strategy. METHODS: This retrospective study included patients with naïve papillae who underwent ERCP between January 2018 and December 2020. Patients, divided into two groups, received initial cannulation using a conventional catheter. After failed cannulation, the second attempt used PCWGC and double-guidewire technique (DGT) in the new and conventional strategy groups, respectively. Propensity score-matching (PSM) analysis compared outcomes between groups. Primary outcome included overall success rate, while secondary outcomes included cannulation time, adverse events, and cannulation difficulty subgroup analysis. RESULTS: The new strategy group comprised 255 (47.6%) of 536 patients who underwent ERCP. The total cannulation success rate was 98.4% (vs. 97.2%, p = 0.318), with similar post-ERCP pancreatitis (PEP) (1.8% vs. 2.4%, p = 0.64) rates. Following 1:1 PSM, 219/438 patients were allocated to both the conventional and new strategy groups, and 46 patients from the difficult cannulation subgroup were distributed evenly among groups. No difference in overall cannulation success rate existed between the groups before (97.2% vs. 98.4%) and after PSM (96.8% vs. 98.2%). The primary cannulation success rate was higher in the conventional strategy group, while the secondary cannulation success rate was higher in the new strategy group. However, the difficult cannulation subgroup PSM results showed that only the salvage cannulation success rate was significant (9/23, 39.1% vs. 18/23, 78.3%, p = 0.007). In the difficult cannulation subgroup, the salvage cannulation success rate for PCWGC was four times higher than DGT (95% confidence interval; 1.129-14.175), with no significant difference in PEP rate (p = 0.571). CONCLUSIONS: PCWGC demonstrated greater efficacy than the conventional salvage technique. PCWGC could be a safe and useful technique, especially for difficult biliary cannulation.

Long-term exposure to house dust mites accelerates lung cancer development in mice.

BACKGROUND: Individuals with certain chronic inflammatory lung diseases have a higher risk of developing lung cancer (LC). However, the underlying mechanisms remain largely unknown. Here, we hypothesized that chronic exposure to house dust mites (HDM), a common indoor aeroallergen associated with the development of asthma, accelerates LC development through the induction of chronic lung inflammation (CLI).  METHODS: The effects of HDM and heat-inactivated HDM (HI-HDM) extracts were evaluated in two preclinical mouse models of LC (a chemically-induced model using the carcinogen urethane and a genetically-driven model with oncogenic KrasG12D activation in lung epithelial cells) and on murine macrophages in vitro. Pharmacological blockade or genetic deletion of the Nod-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome, caspase-1, interleukin-1ß (IL-1ß), and C-C motif chemokine ligand 2 (CCL2) or treatment with an inhaled corticosteroid (ICS) was used to uncover the pro-tumorigenic effect of HDM.  RESULTS: Chronic intranasal (i.n) instillation of HDM accelerated LC development in the two mouse models. Mechanistically, HDM caused a particular subtype of CLI, in which the NLRP3/IL-1ß signaling pathway is chronically activated in macrophages, and made the lung microenvironment conducive to tumor development. The tumor-promoting effect of HDM was significantly decreased by heat treatment of the HDM extract and was inhibited by NLRP3, IL-1ß, and CCL2 neutralization, or ICS treatment. CONCLUSIONS: Collectively, these data indicate that long-term exposure to HDM can accelerate lung tumorigenesis in susceptible hosts (e.g., mice and potentially humans exposed to lung carcinogens or genetically predisposed to develop LC).

Korean clinical practice guidelines on biologics and small molecules for moderate-to-severe ulcerative colitis.

Ulcerative colitis (UC), a relapsing-remitting chronic inflammatory bowel disease (IBD), has a variable natural course but potentially severe disease course. Since the development of anti-tumor necrosis factor (TNF) agents has changed the natural disease course of moderate-to-severe UC, therapeutic options for patients who failed conventional treatments are expanding rapidly. IBD clinical trials have demonstrated the potential efficacy and safety of novel biologics such as anti-integrin α4ß7 and anti-interleukin-12/23 monoclonal antibodies and small molecules such as a Janus kinase inhibitor. Anti-TNF biosimilars also have been approved and are widely used in IBD patients. Wise drug choices should be made considering evidence-based efficacy and safety. However, the best position of these drugs remains several questions, with limited data from direct comparative trials. In addition, there are still concerns to be elucidated on the effect of therapeutic drug monitoring and combination therapy with immunomodulators. The appropriate treatment regimens in acute severe UC and the risk of perioperative use of biologics are unclear. As novel biologics and small molecules have been approved in Korea, we present the Korean guidelines for medical management of adult outpatients with moderate-to-severe UC and adult hospitalized patients with acute severe UC, focusing on biologics and small molecules.

Bowel Preparation Efficacy and Safety of 1 L vs 2 L Polyethylene Glycol With Ascorbic Acid for Colonoscopy: A Randomized Controlled Trial.

INTRODUCTION: Polyethylene glycol with ascorbic acid (PEG/Asc) is a well-established bowel preparation solution with guaranteed effectiveness and safety. A new low-volume agent, 1 L-PEG/Asc, has recently been released. This study aimed to compare the bowel cleansing efficacy and safety of 1 L-PEG/Asc and 2 L-PEG/Asc administered to adult outpatients in a split-dose manner. METHODS: Outpatients undergoing colonoscopy enrolled in a single-blinded, single-center, noninferiority study conducted between July and October 2021 were randomized in a 1:1 manner to a 1 L-PEG/Asc or 2 L-PEG/Asc group. Bowel cleansing was assessed using the Boston Bowel Preparation Scale (BBPS) and the Harefield Cleansing Scale in intention-to-treat and per-protocol populations. RESULTS: Two hundred forty participants were randomized and allocated, with 120 patients in the 1 L and 2 L-PEG/Asc groups, respectively. Noninferiority was demonstrated for overall successful bowel cleansing (BBPS: 92.5% vs 90.8%; 95% confidence interval [CI], -0.054 to 0.087) and the high-quality cleansing rate of the right-sided colon (BBPS = 3, 40.0% vs 35.8%; 95% CI, -0.082 to 0.165; Harefield Cleansing Scale ≥3, 50.0% vs 43.3%; 95% CI, -0.060 to 0.194) in the intention-to-treat population. The overall incidence of adverse events was similar in both groups ([82/120] 68.3% vs [72/120] 60.0%; P = 0.178). The tolerability, acceptability, and compliance rates of both regimens were similar, with no significant differences. DISCUSSION: Compared with 2 L-PEG/Asc, 1 L-PEG/Asc achieved successful overall bowel cleansing efficacy with high-quality cleansing in the proximal colon and proved its noninferiority. Therefore, 1 L-PEG/Asc is an acceptable alternative bowel cleansing solution.

Sirtuin 7 Inhibitor Attenuates Colonic Mucosal Immune Activation in Mice-Potential Therapeutic Target in Inflammatory Bowel Disease.

Accumulating evidence has shown that sirtuin 7 (SIRT7), a mediator of various cellular activities, plays an important role in the pathogenesis of various immune-mediated inflammatory disorders. However, information remains limited regarding the role of SIRT7 in intestinal inflammation. We used a murine colitis model to investigate the role of SIRT7 in intestinal immunity and whether SIRT7 inhibitors could attenuate the intestinal inflammatory response. Mice were divided into three groups: control, colitis-induced, and SIRT7-inhibitor-treated. A colitis mouse model was established by intraperitoneal injection and nasal challenge with ovalbumin, as in our previous study. Quantitative analyses of inflammatory cytokines and SIRT7 levels in the colonic mucosa were performed to compare the changes in inflammatory responses between the three groups. The colitis group showed increased levels of inflammatory cytokines and SIRT7 in the colonic mucosa. The inflammatory reaction was suppressed in colitis-induced mice administered the SIRT7 inhibitor. The qRT-PCR results showed normalization of inflammatory cytokines in the SIRT7 inhibitor-treated group. Histologic study revealed a decrease in the extent of inflammation after SIRT7 treatment. We also observed that the degree of clinical inflammation was improved in SIRT7-treated mice. Our study demonstrated that SIRT7 inhibition attenuated the inflammatory response in the colon of mice, suggesting a possible role for SIRT7 in the pathogenesis of immune-mediated intestinal inflammation.

Observation for the feasibility of a bile duct biopsy technique using a loop-tip guidewire during endoscopic retrograde cholangiopancreatography.

Endoscopists frequently have difficulty approaching biliary lesions using biopsy forceps. The aim of this study was not only to describe an easy technique for biliary biopsy assisted by a looped guidewire but also to present preliminary results regarding its safety and feasibility. A preliminary proof-of-concept study was performed at a single tertiary medical center. Between August 2019 and January 2020, 13 patients with bile duct strictures underwent endoscopic retrograde cholangiopancreatography (ERCP) with a new loop guidewire-assisted forceps approach technique. The efficacy and safety were evaluated using the success rate as the primary outcome and diagnostic yield and complication rates as secondary outcomes. The tissue sampling success rate was 100% (13/13). All samples were acceptable for histopathological analysis. Eleven specimens were confirmed to be adenocarcinomas. After reexamination of the remaining 2 patients, all cases were eventually diagnosed as being malignant. The sensitivity of the single procedure was 84.6% (11/13). There were 2 patients with mild hyperamylasemia, but there were no severe complications with respect to safety. This new technique could enhance the success rate and diagnostic yield and reduce the risk of failure when using the biopsy forceps approach during ERCP.

Intra-instrument channel workable, optical-resolution photoacoustic and ultrasonic mini-probe system for gastrointestinal endoscopy.

There has been a long-standing expectation that the optical-resolution embodiment of photoacoustic tomography could have a substantial impact on gastrointestinal endoscopy by enabling microscopic visualization of the vasculature based on the endogenous contrast mechanism. Although multiple studies have demonstrated the in vivo imaging capability of a developed imaging device over the last decade, the implementation of such an endoscopic system that can be applied immediately when necessary via the instrument channel of a video endoscope has been a challenge. In this study, we developed a 3.38-mm diameter catheter-based, integrated optical-resolution photoacoustic and ultrasonic mini-probe system and successfully demonstrated its intra-instrument channel workability for the standard 3.7-mm diameter instrument channel of a clinical video endoscope based on a swine model. Through the instrument channel, we acquired the first in vivo dual-mode photoacoustic and ultrasonic endoscopic images from the esophagogastric junction of a swine. Further, in a rat colorectum in vivo imaging experiment, we visualized hierarchically developed mesh-like capillary networks with a hole size as small as ~50 µm, which suggests the potential level of image details that could be photoacoustically provided in clinical settings in the future.

Delayed Bronchial Obstruction following Esophageal Stent Implantation: A Case Report.

Airway compression is a rare complication of esophageal stent placement. With the introduction of self-expanding metal stents, the incidence of bronchial obstruction by esophageal stents has decreased. Delayed external airway compression after esophageal stent implantation is rarely reported. We describe a case of left main bronchial obstruction after self-expandable esophageal stent placement. A 70-year-old patient with advanced esophageal cancer visited the emergency room (ER) with worsening cough and dyspnea. He had received palliative concurrent chemoradiotherapy after esophageal self-expanding metal stent (SEMS) insertion three months ago. One month before the ER visit, additional esophageal SEMS placement (stent-in-stent) was performed owing to the development of a tracheoesophageal fistula. After hospitalization, chest radiography revealed a patchy consolidation in the left lower lobe. A diagnosis of pneumonia was made, and the patient was treated with antibiotics. Seven days after antibiotic treatment, the patient developed a fever and severe dyspnea. Auscultation revealed the absence of breath sounds in the left hemithorax. A follow-up chest radiograph showed a white-out of the left hemithorax. Flexible bronchoscopy revealed luminal narrowing of the left main bronchus (LMB) due to external compression. Chest computed tomography further demonstrated compression of the LMB by esophageal stents. This case highlights that esophageal SEMS can present as an emergent and often life-threatening airway obstruction.

Colonic stenting as a bridge to surgery for obstructive colon cancer: is it safe in the long term?

BACKGROUND: The placement of a self-expanding metal stent in patients with obstructive colon cancer is used as a bridge to surgery. However, due to a lack of consensus and insufficient data, the long-term oncologic outcomes after colonic SEMS placement remain unclear. We assessed the long-term oncologic outcomes and adverse effects of colonic stenting for malignant colonic obstruction. METHODS: We included 198 patients admitted to Korea University Anam Hospital between 2006 and 2014 for obstructive colon cancer, of whom 98 underwent SEMS placement as a bridge to surgery and 100 underwent direct surgery without stenting. The clinicopathologic characteristics, overall survival, and disease-free survival were compared. RESULTS: There were no significant differences in long-term oncologic outcomes between the two groups. The median follow-up durations were 61.55 and 58.64 months in the SEMS and DS groups, respectively. There were also no significant differences in the 5-year OS (77.4% vs. 74.2%, p = 0.691) and 5-year DFS (61.7% vs. 71.0%, p = 0.194) rates between the groups. However, the DS group had significantly more early postoperative complications (p = 0.002). CONCLUSIONS: Colonic SEMS deployment as a bridge to surgery did not negatively affect long-term oncologic outcomes when compared with DS. In addition, colonic stenting decreased early postoperative complications and reduced the time for patients to return to normal daily activities.

A simple and efficient cryopreservation method for mouse small intestinal and colon organoids for regenerative medicine.

Organoid cryopreservation method is one of key step in the organoid culture. We aimed to establish a simple and efficient cryopreservation method for mouse small intestinal organoids (MIOs) and colon organoids (MCOs) using various concentrations of cryoprotectant. Based on the theoretical simulation, we optimized the dimethyl sulfoxide (DMSO) concentration by pretreating the organoids with 5, 7.5, and 10% DMSO for 30 min at 4 °C to allow penetration into the organoids and evaluated their viability, proliferation, and function after cryopreservation. Gene expression in the MIOs and staining of lineage markers were examined real-time PCR. The organoids in the DMSO-treated groups as well as the control, expressed ChrgA, Ecad, Muc2, Lyz, villin, and Lgr5, and there are no significant. A forskolin-induced swelling assay for MIOs was performed to confirm normal cystic fibrosis transmembrane conductance regulator (CFTR) activity. Similar forskolin-induced swelling was observed in the DMSO-treated groups and the control. In addition, MCOs were transplanted into mouse colon for confirmation of regeneration therapy efficacy. Thawing organoids were cultured for two and four sequential passages after cryopreservation with 5% DMSO to confirm any changes in the gene expression of lineage markers after subculture. We developed a simple and efficient organoid freezing method using 5% DMSO with low potential toxicity and validated our findings with theoretical simulation.