TET2 guards against unchecked BATF3-induced CAR T cell expansion.

Further advances in cell engineering are needed to increase the efficacy of chimeric antigen receptor (CAR) and other T cell-based therapies1-5. As T cell differentiation and functional states are associated with distinct epigenetic profiles6,7, we hypothesized that epigenetic programming may provide a means to improve CAR T cell performance. Targeting the gene that encodes the epigenetic regulator ten-eleven translocation 2 (TET2)8 presents an interesting opportunity as its loss may enhance T cell memory9,10, albeit not cause malignancy9,11,12. Here we show that disruption of TET2 enhances T cell-mediated tumour rejection in leukaemia and prostate cancer models. However, loss of TET2 also enables antigen-independent CAR T cell clonal expansions that may eventually result in prominent systemic tissue infiltration. These clonal proliferations require biallelic TET2 disruption and sustained expression of the AP-1 factor BATF3 to drive a MYC-dependent proliferative program. This proliferative state is associated with reduced effector function that differs from both canonical T cell memory13,14 and exhaustion15,16 states, and is prone to the acquisition of secondary somatic mutations, establishing TET2 as a guardian against BATF3-induced CAR T cell proliferation and ensuing genomic instability. Our findings illustrate the potential of epigenetic programming to enhance T cell immunity but highlight the risk of unleashing unchecked proliferative responses.

CXCL8/CXCR2 signaling mediates bone marrow fibrosis and is a therapeutic target in myelofibrosis.

Proinflammatory signaling is a hallmark feature of human cancer, including in myeloproliferative neoplasms (MPNs), most notably myelofibrosis (MF). Dysregulated inflammatory signaling contributes to fibrotic progression in MF; however, the individual cytokine mediators elicited by malignant MPN cells to promote collagen-producing fibrosis and disease evolution are yet to be fully elucidated. Previously, we identified a critical role for combined constitutive JAK/STAT and aberrant NF-κB proinflammatory signaling in MF development. Using single-cell transcriptional and cytokine-secretion studies of primary cells from patients with MF and the human MPLW515L (hMPLW515L) murine model of MF, we extend our previous work and delineate the role of CXCL8/CXCR2 signaling in MF pathogenesis and bone marrow fibrosis progression. Hematopoietic stem/progenitor cells from patients with MF are enriched for a CXCL8/CXCR2 gene signature and display enhanced proliferation and fitness in response to an exogenous CXCL8 ligand in vitro. Genetic deletion of Cxcr2 in the hMPLW515L-adoptive transfer model abrogates fibrosis and extends overall survival, and pharmacologic inhibition of the CXCR1/2 pathway improves hematologic parameters, attenuates bone marrow fibrosis, and synergizes with JAK inhibitor therapy. Our mechanistic insights provide a rationale for therapeutic targeting of the CXCL8/CXCR2 pathway among patients with MF.

Predicting tumour content of liquid biopsies from cell-free DNA.

BACKGROUND: Liquid biopsy is a minimally-invasive method of sampling bodily fluids, capable of revealing evidence of cancer. The distribution of cell-free DNA (cfDNA) fragment lengths has been shown to differ between healthy subjects and cancer patients, whereby the distributional shift correlates with the sample's tumour content. These fragmentomic data have not yet been utilised to directly quantify the proportion of tumour-derived cfDNA in a liquid biopsy. RESULTS: We used statistical learning to predict tumour content from Fourier and wavelet transforms of cfDNA length distributions in samples from 118 cancer patients. The model was validated on an independent dilution series of patient plasma. CONCLUSIONS: This proof of concept suggests that our fragmentomic methodology could be useful for predicting tumour content in liquid biopsies.

What Every Gastroenterologist Should Know About Gastrointestinal NETs.

Gastrointestinal neuroendocrine tumors are increasingly common. Practitioners should examine these lesions carefully found on routine endoscopy. Obtaining accurate neuroendocrine tumors stage and grade is critical to patient assessment and management, and assistance from advanced endoscopists may be needed.

Clinical and economic impacts of large volume delayed sampling and pathogen reduction technology platelet processing strategies in the United States.

BACKGROUND: Large volume delayed sampling (LVDS) and pathogen reduction technology (PRT) are strategies for platelet processing to minimize transfusion of contaminated platelet components (PCs). This study holistically compares the economic and clinical impact of LVDS and PRT in the United States. STUDY DESIGN AND METHODS: A decision model was constructed to simulate collection, processing, and use of PCs and to compare processing strategies: PRT with 5-day shelf life, LVDS with 7-day shelf life (LVDS7), and LVDS with 5-day shelf life extended to 7 days with secondary testing (LVDS5/2). Target population was adults requiring two or more transfusions. Collection, processing, storage, and distribution data were obtained from the National Blood Collection and Utilization Survey and published literature. Patient outcomes associated with transfusions were obtained from AABB guidelines, meta-analyses, and other published clinical studies. Costs were obtained from reimbursement schedules and other published sources. RESULTS: Given 10,000 donated units, 9512, 9511, and 9651 units of PRT, LVDS5/2, and LVDS7 PCs were available for transfusion, respectively. With these units, 1502, 2172, and 2329 transfusions can be performed with similar levels of adverse events. Assuming 30 transfusions a day, a hospital would require 69,325, 47,940, and 45,383 units of PRT, LVDS5/2, and LVDS7 platelets to perform these transfusions. The mean costs to perform transfusions were significantly higher with PRT units. CONCLUSIONS: Compared with PRT, LVDS strategies were associated with lower costs and higher PC availability while patients experienced similar levels of adverse events. Increased utilization of LVDS has the potential to improve efficiency, expand patient access to platelets, and reduce health care costs.

Single-use duodenoscopes and duodenoscopes with disposable end caps.

BACKGROUND AND AIMS: Multidrug-resistant infectious outbreaks associated with duodenoscopes have been documented internationally. Single-use duodenoscopes, disposable distal ends, or distal end cap sealants could eliminate or reduce exogenous patient-to-patient infection associated with ERCP. METHODS: This document reviews technologies that have been developed to help reduce or eliminate exogenous infections because of duodenoscopes. RESULTS: Four duodenoscopes with disposable end caps, 1 end sheath, and 2 disposable duodenoscopes are reviewed in this document. The evidence regarding their efficacy in procedural success rates, reduction of duodenoscope bacterial contamination, clinical outcomes associated with these devices, safety, and the financial considerations are discussed. CONCLUSIONS: Several technologies discussed in this document are anticipated to eliminate or reduce exogenous infections during endoscopy requiring a duodenoscope. Although disposable duodenoscopes can eliminate exogenous ERCP-related risk of infection, data regarding effectiveness are needed outside of expert centers. Additionally, with more widespread adoption of these new technologies, more data regarding functionality, medical economics, and environmental impact will accrue. Disposable distal end caps facilitate duodenoscope reprocessing; postmarketing surveillance culture studies and real-life patient infection analyses are important areas of future research.

Endoscopic therapies for gallbladder drainage.

BACKGROUND AND AIMS: Endoscopic management of acute cholecystitis has expanded in patients who are considered nonoperative candidates. Traditionally managed with percutaneous cholecystostomy (PC), improvement in techniques and devices has led to increased use of endoscopic methods for gallbladder drainage. This document reviews technical aspects of endoscopic transpapillary gallbladder drainage (ET-GBD) and EUS-guided GBD (EUS-GBD) as well as their respective technical/clinical success and adverse event rates. Available comparative data are also reviewed among nonsurgical gallbladder drainage techniques (PC, ET-GBD, and EUS-GBD). METHODS: The MEDLINE database was searched through March 2021 for relevant articles by using keywords including "acute cholecystitis," "interventional EUS," "percutaneous cholecystostomy," "transpapillary gallbladder drainage," "EUS-guided gallbladder drainage," "lumen-apposing metal stent," "gallbladder stenting," and "endoscopic gallbladder drainage." The manuscript was drafted by 2 authors and reviewed by members of the American Society for Gastrointestinal Endoscopy Technology Committee and subsequently by the American Society for Gastrointestinal Endoscopy Governing Board. RESULTS: Multiple studies have demonstrated acceptable outcomes comparing PC and both endoscopic gallbladder drainage techniques, ET-GBD and EUS-GBD. Published data suggest that endoscopic gallbladder drainage techniques may be associated with lower rates of adverse events and improved quality of life. However, there are important clinical considerations for choosing among these treatment options, requiring a multidisciplinary and collaborative approach to therapeutic decision-making in these patients. CONCLUSIONS: The implementation of EUS-GBD and ET-GBD in high-risk surgical patients with acute cholecystitis may result in favorable outcomes when compared with PC. Further improvements in techniques and training should lead to more widespread acceptance and dissemination of these treatment options.

Lumen-apposing metal stents (with videos).

BACKGROUND AND AIMS: Lumen-apposing metal stents (LAMSs) are a novel class of devices that have expanded the spectrum of endoscopic GI interventions. LAMSs with their dumbbell configuration, short saddle length, and large inner luminal diameter provide favorable stent characteristics to facilitate anastomosis formation between the gut lumen and adjacent structures. METHODS: The MEDLINE database was searched through April 2021 for articles related to LAMSs by using additional relevant keywords such as "walled-off pancreatic necrosis," "pseudocysts," "pancreatic fluid collection," "cholecystitis," "gastroenterostomy," in addition to "endoscopic treatment" and "endoscopic management," among others. RESULTS: This technology review describes the full spectrum of LAMS designs and delivery systems, techniques for deployment, procedural outcomes, safety, training issues, and financial considerations. CONCLUSIONS: Although LAMSs were initially introduced for drainage of pancreatic pseudocysts and walled-off necrosis, the versatility of these devices has led to a variety of off-label uses including gallbladder drainage, enteric bypass with the creation of gastroenterostomies, and treatment of luminal GI strictures.

ASGE guideline on the role of endoscopy in the management of benign and malignant gastroduodenal obstruction.

This American Society for Gastrointestinal Endoscopy guideline provides evidence-based recommendations for the endoscopic management of gastric outlet obstruction (GOO). We applied the Grading of Recommendations, Assessment, Development and Evaluation methodology to address key clinical questions. These include the comparison of (1) surgical gastrojejunostomy to the placement of self-expandable metallic stents (SEMS) for malignant GOO, (2) covered versus uncovered SEMS for malignant GOO, and (3) endoscopic and surgical interventions for the management of benign GOO. Recommendations provided in this document were founded on the certainty of the evidence, balance of benefits and harms, considerations of patient and caregiver preferences, resource utilization, and cost-effectiveness.

Ubiquitously transcribed genes use alternative polyadenylation to achieve tissue-specific expression.

More than half of human genes use alternative cleavage and polyadenylation (ApA) to generate mRNA transcripts that differ in the lengths of their 3' untranslated regions (UTRs), thus altering the post-transcriptional fate of the message and likely the protein output. The extent of 3' UTR variation across tissues and the functional role of ApA remain poorly understood. We developed a sequencing method called 3'-seq to quantitatively map the 3' ends of the transcriptome of diverse human tissues and isogenic transformation systems. We found that cell type-specific gene expression is accomplished by two complementary programs. Tissue-restricted genes tend to have single 3' UTRs, whereas a majority of ubiquitously transcribed genes generate multiple 3' UTRs. During transformation and differentiation, single-UTR genes change their mRNA abundance levels, while multi-UTR genes mostly change 3' UTR isoform ratios to achieve tissue specificity. However, both regulation programs target genes that function in the same pathways and processes that characterize the new cell type. Instead of finding global shifts in 3' UTR length during transformation and differentiation, we identify tissue-specific groups of multi-UTR genes that change their 3' UTR ratios; these changes in 3' UTR length are largely independent from changes in mRNA abundance. Finally, tissue-specific usage of ApA sites appears to be a mechanism for changing the landscape targetable by ubiquitously expressed microRNAs.

American Society for Gastrointestinal Endoscopy guideline on the role of endoscopy in familial adenomatous polyposis syndromes.

Familial adenomatous polyposis (FAP) syndrome is a complex entity, which includes FAP, attenuated FAP, and MUTYH-associated polyposis. These patients are at significant risk for colorectal cancer and carry additional risks for extracolonic malignancies. In this guideline, we reviewed the most recent literature to formulate recommendations on the role of endoscopy in this patient population. Relevant clinical questions were how to identify high-risk individuals warranting genetic testing, when to start screening examinations, what are appropriate surveillance intervals, how to identify endoscopically high-risk features, and what is the role of chemoprevention. A systematic literature search from 2005 to 2018 was performed, in addition to the inclusion of seminal historical studies. Most studies were from worldwide registries, which have compiled years of data regarding the natural history and cancer risks in this cohort. Given that most studies were retrospective, recommendations were based on epidemiologic data and expert opinion. Management of colorectal polyps in FAP has not changed much in recent years, as colectomy in FAP is the standard of care. What is new, however, is the developing body of literature on the role of endoscopy in managing upper GI and small-bowel polyposis, as patients are living longer and improved endoscopic technologies have emerged.

ASGE guideline on minimum staffing requirements for the performance of GI endoscopy.

Efforts to increase patient safety and satisfaction, a critical concern for health providers, require periodic evaluation of all factors involved in the provision of GI endoscopy services. We aimed to develop guidelines on minimum staffing requirements and scope of practice of available staff for the safe and efficient performance of GI endoscopy. The recommendations in this guideline were based on a systematic review of published literature, results from a nationwide survey of endoscopy directors, along with the expert guidance of the American Society for Gastrointestinal Endoscopy (ASGE) Standards of Practice Committee members, ASGE Practice Operation Committee members, and the ASGE Governing Board.

ASGE guideline on the management of achalasia.

Achalasia is a primary esophageal motor disorder of unknown etiology characterized by degeneration of the myenteric plexus, which results in impaired relaxation of the esophagogastric junction (EGJ), along with the loss of organized peristalsis in the esophageal body. The criterion standard for diagnosing achalasia is high-resolution esophageal manometry showing incomplete relaxation of the EGJ coupled with the absence of organized peristalsis. Three achalasia subtypes have been defined based on high-resolution manometry findings in the esophageal body. Treatment of patients with achalasia has evolved in recent years with the introduction of peroral endoscopic myotomy. Other treatment options include botulinum toxin injection, pneumatic dilation, and Heller myotomy. This American Society for Gastrointestinal Endoscopy Standards of Practice Guideline provides evidence-based recommendations for the treatment of achalasia, based on an updated assessment of the individual and comparative effectiveness, adverse effects, and cost of the 4 aforementioned achalasia therapies.

Acute and outpatient service utilisation prior to, during, and following enrolment in community-based mental health treatment among children and youth in Central Ontario: A proof of concept for cross-sectoral data linkage.

AIM: Given the fragmentation of mental health and addictions (MHA) services for children and youth, comprehensive data on utilisation patterns are lacking. We sought to describe MHA-related service use across the community, acute and outpatient sectors. METHODS: We used linked health-administrative data sets to identify a cohort of individuals aged <18 who received MHA treatment in a large community organisation in Ontario, Canada between 1 April 2007 and 31 March 2012. We described their socio-demographic characteristics, examined their MHA-related concurrent service use in acute care and outpatient physician settings (primary care providers, paediatricians and psychiatrists), and compared service utilisation prior to, during and following enrolment using Poisson regressions. RESULTS: Among 7285 children and youth receiving community MHA treatment, there were 481 concurrent MHA-related emergency department visits, 173 hospitalisations and 12140 outpatient physician visits. The average age at enrolment was 10.5 years, and 64% of clients were enrolled for ≥3 months. MHA-related emergency department use significantly declined from 1 year prior, compared to 1 year following receipt of community MHA treatment (112 vs. 82 visits per 1000 person-years, P < 0.001), particularly in females, ages 10-14, those living in higher-income neighbourhoods and urban areas, and those with anxiety disorders. MHA hospitalisations also declined (45 vs. 32, P < 0.001), while outpatient physician visits increased (1750 vs. 1874, P < 0.001). CONCLUSIONS: Our study suggests that community-based MHA treatment may be effective in diverting children and youth away from acute care and highlights the importance of data linkage as a means to better understand the complexity of cross-sectoral MHA service use.

ASGE review of adverse events in colonoscopy.

Colonoscopy is the most commonly performed endoscopic procedure and overall is considered a low-risk procedure. However, adverse events (AEs) related to this routinely performed procedure for screening, diagnostic, or therapeutic purposes are an important clinical consideration. The purpose of this document from the American Society for Gastrointestinal Endoscopy's Standards of Practice Committee is to provide an update on estimates of AEs related to colonoscopy in an evidence-based fashion. A systematic review and meta-analysis of population-based studies was conducted for the 3 most common and important serious AEs (bleeding, perforation, and mortality). In addition, this document includes an updated systematic review and meta-analysis of serious AEs (bleeding and perforation) related to EMR and endoscopic submucosal dissection for large colon polyps. Finally, a narrative review of other colonoscopy-related serious AEs and those related to specific colonic interventions is included.

ASGE guideline on the role of endoscopy for bleeding from chronic radiation proctopathy.

Chronic radiation proctopathy is a common sequela of radiation therapy for malignancies in the pelvic region. A variety of medical and endoscopic therapies have been used for the management of bleeding from chronic radiation proctopathy. In this guideline, we reviewed the results of a systematic search of the literature from 1946 to 2017 to formulate clinical questions and recommendations on the role of endoscopy for bleeding from chronic radiation proctopathy. The following endoscopic modalities are discussed in our document: argon plasma coagulation, bipolar electrocoagulation, heater probe, radiofrequency ablation, and cryoablation. Most studies were small observational studies, and the evidence for effectiveness of endoscopic therapy for chronic radiation proctopathy was limited because of a lack of controlled trials and comparative studies. Despite this limitation, our systematic review found that argon plasma coagulation, bipolar electrocoagulation, heater probe, and radiofrequency ablation were effective in the treatment of rectal bleeding from chronic radiation proctopathy.

ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis.

Each year choledocholithiasis results in biliary obstruction, cholangitis, and pancreatitis in a significant number of patients. The primary treatment, ERCP, is minimally invasive but associated with adverse events in 6% to 15%. This American Society for Gastrointestinal Endoscopy (ASGE) Standard of Practice (SOP) Guideline provides evidence-based recommendations for the endoscopic evaluation and treatment of choledocholithiasis. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to rigorously review and synthesize the contemporary literature regarding the following topics: EUS versus MRCP for diagnosis, the role of early ERCP in gallstone pancreatitis, endoscopic papillary dilation after sphincterotomy versus sphincterotomy alone for large bile duct stones, and impact of ERCP-guided intraductal therapy for large and difficult choledocholithiasis. Comprehensive systematic reviews were also performed to assess the following: same-admission cholecystectomy for gallstone pancreatitis, clinical predictors of choledocholithiasis, optimal timing of ERCP vis-à-vis cholecystectomy, management of Mirizzi syndrome and hepatolithiasis, and biliary stent therapy for choledocholithiasis. Core clinical questions were derived using an iterative process by the ASGE SOP Committee. This body developed all recommendations founded on the certainty of the evidence, balance of risks and harms, consideration of stakeholder preferences, resource utilization, and cost-effectiveness.

Imaging of Lumen-Apposing Metal Stents in Abdominopelvic Applications.

OBJECTIVE. Lumen-apposing metal stents (LAMS) are increasingly being used for abdominopelvic drainage applications. The purpose of this article is to describe the normal imaging appearance of these stents and the radiologic findings in stent-related complications. CONCLUSION. LAMS facilitate effective drainage, but the complications include bleeding, pseudoaneurysm formation, stent occlusion, and stent migration.