Buttar, Navtej

Abstract Background and study aim The role of esophageal overtubes in upper gastrointestinal endoscopic suturing is unknown. This study aimed to determine whether overtube use was associated with technical success or adverse events. Patients and methods A retrospective review of consecutive patients who underwent endoscopic suturing for various indications was performed. Results A total of 719 patients underwent endoscopic suturing for various indications, including endoscopic bariatric procedures in 262, stent fixation in 258, defect closure in 190, and hemostasis in nine. An overtube was used in 186 procedures (25.9 %). Technical success was achieved in all cases. Minor mucosal trauma occurred in 15 cases (8.1 %) with use of an overtube, and none without an overtube (P < 0.0001). No full-thickness esophageal perforation or hemorrhage related to overtube use or the suturing device occurred. Conclusions Endoscopic suturing can be performed safely for a variety of indications, including endoscopic bariatric procedures, defect repair, and stent fixation without an esophageal overtube. Minor esophageal mucosal trauma and equipment cost are increased when an overtube is used.

OBJECTIVES: Expression of prostaglandin biosynthetic pathway enzymes in mucinous pancreatic cysts is unknown. Cyclooxygenase-2 (COX-2) inhibition is a potential cancer chemoprevention strategy for these lesions. We evaluated the expression of COX-2, cytosolic phospholipase A2 (cPLA2), and protein kinase B (AKT) in the epithelium of pancreatic cysts and correlated enzyme expression with aspirin (ASA) use and cyst fluid prostaglandin E 2 (PGE 2 ) concentration. METHODS: Pathology of 80 resected pancreatic cysts was reviewed. Expression of COX-2, cPLA2, and AKT was quantified by tissue immunohistochemistry immunoreactivity scores (IRSs). IRS values were compared between cyst types and (in 30 cases) with matched cyst fluid PGE 2 concentrations. RESULTS: The mean IRS was higher in the epithelium of mucinous vs nonmucinous cysts for COX-2 (6.1 ± 4.7 vs 3.2 ± 2.8, P = 0.01) and cPLA2 (6.9 ± 3.0 vs 2.9 ± 2.9, P < 0.001). Cyst epithelial COX-2 expression was higher in mucinous cysts with low-grade dysplasia vs those with high-grade dysplasia or invasive carcinoma (IRS 8.0 ± 3.9 vs 1.5 ± 2.9, P < 0.001), whereas the opposite was found for cPLA2 (6.2 ± 3.0 vs 8.6 ± 2.3, P = 0.005). Cyst fluid PGE 2 concentrations did not correlate with either the IRS or a history of low- to moderate-dose ASA use. CONCLUSIONS: COX-2 and cPLA2 are overexpressed in the epithelium of mucinous pancreatic cysts. COX-2 and/or cPLA2 inhibition might prevent the emergence or progression of mucinous pancreatic cysts, but higher doses of ASA or nonsteroidal anti-inflammatory drugs may be necessary to substantially inhibit cyst epithelial COX-2 activity.

Abstract Background Post-surgical complications such as leaks are the source of considerable morbidity and mortality. Success of conservative interventions is highly variable. Recurrence after surgical repair is also not uncommon. Our aim was to develop novel endoscopic strategies to maximize negative intracavitary pressure to manage leaks in cases where conventional management either failed or were not feasible. Methods We have used transluminal locking loop drains with low intermittent suction in the management of non-healing leaks in various areas. An example presented here illustrates this concept where a 68-year-old male patient underwent paraesophageal hernia repair with Nissen fundoplication. Patient presented 3 weeks later with fistula leading to a 13 cm meditational abscess. Patient developed right hemiparesis requiring tissue plasminogen activator (tPA). Post-tPA patient developed hemoptysis and hematemesis requiring emergency intubation. The defect in the esophagus was 6–8 mm. Endoscopic repair with stitching or clipping would have left a large undrained cavity with a potential to expand. Endoscopic repair with transcutaneous drain placement was challenging due to recent tPA and a difficult location. Moreover there was potential to develop esophago- pleural- broncho- cutaneous fistula. Endoscopic vacuum therapy was felt to be a suboptimal choice. Patient was high-risk surgical candidate as it would have required radical surgery in the setting of tPA.Upper endoscopy was performed and the cavity was debrided. No direct communication with bronchopulmonary tree noted. A transnasal guidewire assisted 16 Fr, 60 cm locking loop drain was placed and connected to low intermittent suction that was switched to bulb based suction. Results The output from naso-cavity drain decreased nearly 100 cc per day in the first 5 days and the size reduced by 30, 50 and 80% by day 5, 9 and 12 respectively. Near complete elimination of the cavity was observed on day 15. Esophagogram showed complete resolution of the leak and computerized tomography revealed no residual cavity Conclusion Developing transluminal endoscopic strategies to maximize negative intracavitary pressure helps expedite the healing of resistant postsurgical leaks. This technique avoids the need for frequent drain changes that remains a challenge for vacuum therapy. Disclosure All authors have declared no conflicts of interest.

AbstractDespite improvements in operative strategies for esophageal resection, anastomotic leaks, fistula, postoperative pulmonary complications, and chylothorax can occur. Our review seeks to identify potential risk factors, modalities for early diagnosis, and novel interventions that may ameliorate the potential adverse effects of these surgical complications following esophagectomy.

Goals: To investigate factors predictive of progression from nondysplastic Barrett esophagus (NDBE) or low-grade dysplasia (LGD) to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) using a large, prospective cohort of patients, wherein all esophageal biopsies undergo expert gastrointestinal pathologist review. Background: Efficacy and cost-effectiveness of endoscopic surveillance to detect incident EAC in the setting of Barrett esophagus (BE), particularly in NDBE patients, is questioned. Previous studies have reported factors predictive of progression to EAC to guide surveillance intervals, but their strength is limited by small sample size and absence of expert gastrointestinal pathologist involvement in esophageal biopsy review. Study: NDBE and LGD subjects were identified from a prospective registry in a tertiary care center. “Progressors” were BE subjects who developed HGD/EAC>12 months after the initial NDBE or LGD diagnosis. Cox proportional hazards model were used to identify predictors of progression. Results: In total, 318 with NDBE and 301 with BE-LGD (mean age, 62.6 y, 85% male) were included. The mean follow-up was 5.3 years. The 7 NDBE and 21 LGD subjects progressed to HGD/EAC. BE length [hazards ratio (HR), 1.16; 95% confidence interval (CI), 1.03-1.29], presence of nodularity (HR, 4.98; 95% CI, 1.80-11.7), and baseline LGD (HR, 2.57; 95% CI, 1.13-6.57) were significant predictors of progression on multivariate analysis. Conclusions: In this well-defined cohort of NDBE and BE-LGD subjects, BE length, presence of LGD, and nodularity were independent predictors of progression to HGD/EAC. These factors may aid in identifying high-risk patients who may benefit from closer endoscopic surveillance/therapy.

Abstract Background and aims Benign gastrointestinal (GI) strictures are often refractory to standard endoscopic interventions. Fully covered coaxial lumen-apposing metal stents (LAMS) have emerged as a novel therapy for these strictures. The aim of this study was to evaluate the safety and efficacy of LAMS for refractory GI strictures. Patients and methods A retrospective analysis was performed for patients who underwent LAMS placement for benign luminal strictures in three US centers between January 2014 and December 2016. The primary outcomes were technical success and initial clinical success of LAMS placement. Secondary outcomes were stent migration, rate of re-intervention, and adverse events. Results A total of 49 patients underwent 56 LAMS placement procedures. Previous treatment had failed in 39 patients (79.6 %), and anastomotic strictures were the indication in 77.6 % (38/49), with the most common site being gastrojejunal (34.7 % [17/49]). Technical success was achieved in all procedures and initial clinical success was achieved in 96.4 % of all procedures (54/56). Patient initial clinical success was 95.9 % (47/49). Stent migration occurred in 17.9 % of procedures, and was more likely to occur at sites in the lower GI tract (P = 0.02). The mean stent dwell time was 100.6 days, and the mean follow-up was 169.8 days. Minor adverse events, not requiring hospitalization, occurred in 33.9 % of procedures, including subsequent stricture progression (10.7 %). In cases where LAMS were removed, mean follow-up time was 102.2 days. The re-intervention rate was 75 % at 300 days follow-up after stent removal. Of the LAMS placed at anastomotic strictures, 36.4 % required re-intervention, with approximately two-thirds of these re-interventions requiring placement of a new stent or surgery. Conclusion LAMS placement was successful for the management of refractory GI strictures, with good technical and initial clinical success rates. However, re-intervention rates after LAMS removal were high, and many strictures were not resolved by an extended period of stenting with these coaxial stents. LAMS placement offers additional therapeutic options and in selected cases might be considered a destination therapy for patients with recalcitrant benign strictures.

Abstract Cancer has been considered a heterogeneous disease, which mainly arises from the accumulation of genetic mutations, leading to a loss of tumor suppressor genes, as well as to an activation of oncogenes. The epigenetic mechanisms, such as DNA and histone modifications, are processes that regulate gene expression, and an alteration of these can contribute to cancer progression. Methylation on histone 3 lysine 9 (H3K9), in particular di-methyl (H3K9me2), is mainly mediated by the nuclear histone lysine methyltransferase G9a. Preliminary data showed that G9a was overexpressed in aggressive and highly metastatic forms of cancer. However, to date, this pathway has remained unstudied in esophageal adenocarcinoma. Interestingly, epigenetic drugs, such as those that target G9a, have the potential to reverse the adverse effects acquired downstream from genetic mutations, which currently cannot be directly repaired or targeted. In the current study, we utilize BRD4770, an S-adenosylmethionine (SAM) mimetic inhibitor of G9a, to determine the benefits of inhibiting this pathway in the context of esophageal adenocarcinoma. We hypothesize that pharmacological targeting of G9a by BRD4770 inhibits esophageal adenocarcinoma cell growth. To examine G9a-mediated dimethyl histone H3K9 levels in esophageal adenocarcinoma, we performed immunohistochemistry on paraffin-embedded esophageal adenocarcinoma tissues with an H3K9me2 antibody. In order to confirm specificity of BRD4770 in regulating the dimethyl histone H3K9 levels, and thus trimethyl H3K9 levels, in esophageal adenocarcinoma, we treated human esophageal adenocarcinoma cells (SKGT-4) with different doses of BRD4770 at various time points for western blot analysis using antibodies against histone H3K9me2 and H3K9me3. Moreover, we found that treatment of SKGT-4 cells with BRD4770 significantly inhibits cell proliferation by MTS assay, as well as clonogenic survival. Therefore, to determine the mechanism(s) by which BRD4770 inhibits the growth of esophageal adenocarcinoma cells, we utilized Caspase-3, Senescence, and Autophagy Assays. Our data shows that inhibition of G9a by BRD4770 does not induce Caspase 3 activity, while it significantly increases senescence and autophagy. Combined, our results suggest that BRD4770 has an important pharmacological role in regulating methyl histone H3K9 levels that may lead to inhibition of esophageal adenocarcinoma cell growth via an increase in senescence and autophagy. Further studies are focused on in vivo models to understand these effects in more detail, however the fact that an anti-G9a drug antagonizes esophageal adenocarcinoma cell growth raises optimism for its potential in the treatment of this malignancy. Note: This abstract was not presented at the meeting. Citation Format: Mabel G. Perez-Oquendo, Gwen A. Lomberk, Raul A. Urrutia, Sarah Kossak, Navtej Buttar, Sounak Gupta. Treatment with the G9a antagonist, BRD4770, inhibits esophageal adenocarcinoma cell growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-094. doi:10.1158/1538-7445.AM2017-LB-094

Esophageal varices are a significant complication of portal hypertension. Endoscopic variceal ligation (EVL) is one of the clinical standards for treating these varices and preventing their hemorrhage. Limitations of EVL include the risk of stricture formation and postband ulcer bleeding due to the damage caused to the esophageal mucosa, as well as the need for multiple endoscopic treatment sessions to eradicate the varices. The goal of this study is to develop a device and evaluate the technical feasibility of microwave ablation to seal esophageal varices, while preventing thermal damage to the surface mucosal tissue. A microwave applicator with a directional radiation pattern was developed for endoscopic ablation of esophageal varices. Electromagnetic and bioheat transfer computational models were employed to optimize the design of the microwave applicator and evaluate energy delivery strategies for this application. Experiments in ex vivo and in vivo tissue were employed to verify simulation results. Simulations predicted enhanced heating performance of the antenna using an angled monopole radiating element. Further, simulations indicate that while the endoscopic cap attenuated electric fields in tissue, it also enhanced surface cooling of tissue, increasing the likelihood of preserving mucosal tissue. Experiments in ex vivo tissue indicated the feasibility of sealing veins with 77 W microwave power delivered for 30 s. In vivo experiments demonstrated the ability to seal veins, while preserving surface tissue. This study demonstrated the technical feasibility of microwave thermal ablation for treating esophageal varices using a 2.45 GHz water-cooled directional microwave applicator.

Abstract The current integrative pathobiologic hypothesis states that pancreatic cancer (PDAC) develops and progresses in response to an interaction between known oncogenes and downstream epigenomic regulators. Congruently, this study tests a new combinatorial therapy based on the inhibition of the Aurora kinase A (AURKA) oncogene and one of its targets, the H3K9 methylation–based epigenetic pathway. This therapeutic combination is effective at inhibiting the in vitro growth of PDAC cells both, in monolayer culture systems, and in three-dimensional spheroids and organoids. The combination also reduces the growth of PDAC xenografts in vivo. Mechanistically, it was found that inhibiting methyltransferases of the H3K9 pathway in cells, which are arrested in G2–M after targeting AURKA, decreases H3K9 methylation at centromeres, induces mitotic aberrations, triggers an aberrant mitotic check point response, and ultimately leads to mitotic catastrophe. Combined, these data describe for the first time a hypothesis-driven design of an efficient combinatorial treatment that targets a dual oncogenic–epigenomic pathway to inhibit PDAC cell growth via a cytotoxic mechanism that involves perturbation of normal mitotic progression to end in mitotic catastrophe. Therefore, this new knowledge has significant mechanistic value as it relates to the development of new therapies as well as biomedical relevance. Implications: These results outline a model for the combined inhibition of a genetic-to-epigenetic pathway to inhibit cell growth and suggest an important and provocative consideration for harnessing the capacity of cell-cycle inhibitors to enhance the future use of epigenetic inhibitors. Mol Cancer Res; 15(8); 984–97. ©2017 AACR.