Innovative submucosal injection solution for endoscopic resection with phosphorylated pullulan: a preclinical study.

BACKGROUND AND AIMS: A submucosal injection solution is used to assist in endoscopic surgery. The high viscosity of current solutions makes them difficult to inject. In the present study, we developed an extremely low-viscosity, easy-to-use submucosal injection solution using phosphorylated pullulan (PPL). METHODS: The PPL solutions were prepared at different concentrations, and their viscosities were measured. The mucosal elevation capacity was evaluated using excised porcine stomachs. Controls included 0.4% sodium hyaluronate (SH), 0.6% sodium alginate (SA), and saline. To evaluate the practicality, the catheter injectability of 0.7% PPL was measured, and EMR and endoscopic submucosal dissection (ESD) were performed using the stomach and colorectum of live pigs. As controls, 0.4% SH and saline were used. RESULTS: The PPL solutions were of extremely low viscosity compared to the solutions of 0.4% SH and 0.6% SA. Nevertheless, the mucosal elevation capacity of PPL solutions for up to 0.7% concentration was similar to that of 0.4% SH, and 0.7% PPL was less resistant to catheter infusion than 0.4% SH and 0.6% SA. In live pig experiments with endoscopic mucosal resection and ESD, snaring after submucosal injection of 0.7% PPL was easier than with 0.4% SH, ESD with 0.7% PPL produced less bubble formation than with 0.4% SH, and the procedure time tended to be shorter with 0.7% PPL than with 0.4% SH because of the shorter injection time. CONCLUSIONS: The PPL solution is an innovative and easy-to-use submucosal injection solution.

Adverse Events after Different Endoscopic Resection Procedures for Small and Intermediate-Sized Colorectal Polyps.

INTRODUCTION: Cold snare polypectomy (CSP) and underwater endoscopic mucosal resection (UEMR) have been developed recently, in addition to conventional methods, but adverse events of each method have not been fully clarified. We compared the outcomes of each method for the appropriate choice. METHODS: Patients who underwent CSP, endoscopic mucosal resection (EMR)/hot snare polypectomy (HSP), or UEMR for small and intermediate-sized colorectal polyps between April 2017 and June 2020 were retrospectively examined. The rate of adverse events and recurrences due to each method were determined as the main outcomes. Clinical factors related to adverse events were examined. RESULTS: A total of 1,025 patients with 3,163 polyps underwent polypectomy using any of the methods. CSP, EMR/HSP, and UEMR were performed for 704 (22.2%), 2,145 (67.8%), and 314 polyps (9.9%), and the median size for each method was 4, 6, and 7 mm, respectively. Delayed bleeding for CSP, EMR/HSP, and UEMR was 0%, 0.2%, and 0.6% (p = 0.15), and perforation was 0%, 0.1%, and 0%, respectively (p = 0.62). Recurrence after CSP, EMR/HSP, and UEMR was 0.3%, 0.09%, and 1.3%, respectively (p < 0.01). Recurrence for UEMR was significantly higher in the early stage of procedure introduction (p = 0.015). Oral anticoagulants were the risk factor for delayed bleeding (p < 0.01, respectively). CONCLUSION: There was no significant difference regarding adverse events among each method for small and intermediate-sized polyps, although the recurrence rate after UEMR was higher than other methods.

Utility of Combined Use of Transabdominal Ultrasonography and Fecal Immunochemical Test Examinations in Ulcerative Colitis.

This study examined the utility of the combined use of transabdominal ultrasonography (TUS) and fecal immunochemical testing (FIT) to detect mucosal inflammation, vis-a-vis the Mayo endoscopic subscore (MES), in ulcerative colitis (UC). Sixty-three UC patients who underwent TUS and FIT were retrospectively enrolled. For TUS, the colon was divided into five segments, and the bowel wall thickness was measured and evaluated. The accuracy of FIT (> 100 ng/ml) in detecting mucosal inflammation (MES>0) was 0.93, whereas that of TUS (BWT>2 mm) in each segment was 0.84-0.97. The combined use of TUS and FIT may be helpful in noninvasive treatment strategies.

Prognotic impact of serum follistatin in patients with hepatocellular carcinoma.

BACKGROUND AND AIM: Follistatin (FST) is a glycoprotein expressed in most organs, which interacts with activins or other members of the transforming growth factor beta family. Recently, several reports have shown that FST regulates a variety of processes during tumor progression. Here, serum FST in patients with liver diseases was measured, and its clinical utility as a biomarker was assessed. METHODS: Serum was collected from 162 patients (91 hepatocellular carcinoma [HCC], 43 liver cirrhosis, and 28 chronic hepatitis) as well as from 16 healthy volunteers. FST was quantified by enzyme-linked immunosorbent assays, and levels were compared with clinical parameters including survival of the HCC patients. RESULTS: Median serum FST levels in HCC, liver cirrhosis, chronic hepatitis, and healthy volunteers were 1168, 1606, 1324, and 1661 pg/mL, respectively, not significantly different. In HCC patients, higher serum FST was associated with greater age, hepatitis C virus antibody-negativity, large tumor size, g-glutamyl transpeptidase, des-gamma carboxyprothrombin and presence of portal vein tumor thrombus. Survival of HCC patients with high FST levels was significantly shorter than for those with low levels (P = 0.004). Multivariate analysis revealed that in addition to large tumor size and presence of portal vein thrombus, high FST levels were independently correlated with poor prognosis (hazard ratio = 2.41, 95% confidence interval = 1.16-5.00, P = 0.02). CONCLUSIONS: Serum FST levels are significantly associated with HCC prognosis and could represent a predictive biomarker in this disease.

Modified line-assisted complete closure of the defect after gastric endoscopic full-thickness resection: a pilot study in porcine models.

Background and study aims Closure after endoscopic full-thickness resection (EFTR) is challenging. We previously developed a simple endoscopic closure method: line-assisted complete closure (LACC). We performed a pilot study using porcine models to evaluate the feasibility of modified LACC after gastric EFTR. Patients and methods Six live pigs were included. EFTR (greater curvature of the gastric antrum [n = 3] and anterior wall of the gastric body [n = 3]) was performed under general anesthesia and the defect after EFTR was closed by modified LACC. The pigs were observed until postoperative day 4 (Day 4). The closure site was endoscopically evaluated and the presence or absence of peritonitis and fluid leakage was evaluated. The outcomes were the success rate of modified LACC on the day of the procedure, maintenance of defect closure, presence of peritonitis or leakage, and clinical course. Results Once complete closure was successfully achieved in all cases, maintenance of closure on Day 4 was not achieved. However, there was neither peritonitis nor fluid leakage. The defect was completely covered by surrounding tissues on Day 4 and the clinical course was good in all cases. Conclusions The feasibility of modified LACC after gastric EFTR was demonstrated in porcine models. Further improvement is needed to maintain defect closure.

Resection depth for small colorectal polyps comparing cold snare polypectomy, hot snare polypectomy and underwater endoscopic mucosal resection.

Background and study aims Small colorectal polyps are removed by various methods, including cold snare polypectomy (CSP), hot snare polypectomy (HSP), and underwater endoscopic mucosal resection (UEMR), but the indications for using these methods are unclear. We retrospectively assessed the efficacy of CSP, HSP, and UEMR for small polyps, focusing on the depth of the resected specimens. Patients and methods Outpatients with non-pedunculated small polyps (endoscopically diagnosed as 6 to 9 mm), resected by two endoscopists between July 2019 and September 2020, were enrolled. We histologically evaluated the specimens resected via CSP, HSP, and UEMR. The main outcome was the containment rate of the muscularis mucosa (MM) and submucosa (SM) tissues. Results Forty polyps resected via CSP (n = 14), HSP (n = 12), or UEMR (n = 14) were enrolled after excluding 13 polyps with resection depths that were difficult to determine. The rates of specimens containing MM and SM tissue differed significantly (57 % and 29 % for CSP, 92 % and 83 % for HSP, and 100 % and 100 % for UEMR, respectively ( P  = 0.005 for MM and P  < 0.001 for SM tissue). Multiple logistic regression analysis showed UEMR was an independent factor relating to the containment of SM tissue. The thickness of SM tissue by CSP, HSP, and UEMR were 52 µm, 623 µm, and 1119 µm, respectively ( P  < 0.001). The thickness by CSP was significantly less than those by HSP and UEMR ( P  < 0.001, Bonferroni correction). Conclusions UEMR could be the best method to contain SM tissue without injection. Further studies are needed to evaluate the indication of UEMR for small polyps.

Clinicopathological examination of ESD as salvage therapy for esophageal cancer after definitive chemo-radiation therapy.

BACKGROUND AND STUDY AIMS: Salvage therapy for esophageal cancer following chemo-radiation therapy (CRT) has not been established. We aimed to evaluate endoscopic submucosal dissection (ESD) as a salvage therapy based on histopathological features of lesions. PATIENTS AND METHODS: We compared 10 lesions in eight patients with local residual, recurrent, or metachronous esophageal squamous cell carcinoma treated by ESD after CRT (CRT group) and 59 lesions treated by ESD without CRT (non-CRT group) during the same period. RESULTS: The en bloc resection rate was 100 % while the complete resection rate was 80.0 % in the lesions after CRT, indicating no difference between the CRT and non-CRT groups. Pathological examination showed that fibrosis was more intense in the lamina propria mucosa, muscularis mucosa, and submucosa. The muscularis mucosa was thicker in both non-tumor and tumor sites in the CRT group compared to the non-CRT group. However, severe submucosal fibrosis was observed only in one lesion in the CRT group. The maximum diameter of the submucosal artery was significantly larger in the CRT group ( P  < 0.001). CONCLUSIONS: Compared to the non-CRT group, the lesions in the CRT group were accompanied by fibrosis while the muscularis mucosa were thicker; however, severe fibrosis of the submucosa was rare. It is important to dissect the muscularis mucosa appropriately during ESD, which makes successful dissection of the submucosa possible. Attention should be paid to bleeding from large arteries.