Christopher G. Chapman

The emerging role of miRNAs in inflammatory bowel disease: a review

Inflammatory bowel disease (IBD), comprised of ulcerative colitis and Crohn’s disease, is believed to develop as a result of a deregulated inflammatory response to environmental factors in genetically susceptible individuals. Despite advances in understanding the genetic risks of IBD, associated single nucleotide polymorphisms have low penetrance, monozygotic twin studies suggest a low concordance rate, and increasing worldwide IBD incidence leave gaps in our understanding of IBD heritability and highlight the importance of environmental influences. Operating at the interface between environment and heritable molecular and cellular phenotypes, microRNAs (miRNAs) are a class of endogenous, small noncoding RNAs that regulate gene expression. Studies to date have identified unique miRNA expression profile signatures in IBD and preliminary functional analyses associate these deregulated miRNAs to canonical pathways associated with IBD pathogenesis. In this review, we summarize and discuss the miRNA expression signatures associated with IBD in tissue and peripheral blood, highlight miRNAs with potential future clinical applications as diagnostic and therapeutic targets, and provide an outlook on how to develop miRNA based therapies.

Acquisition of Portal Venous Circulating Tumor Cells From Patients With Pancreaticobiliary Cancers by Endoscopic Ultrasound.

BACKGROUND & AIMS Tumor cells circulate in low numbers in peripheral blood; their detection is used predominantly in metastatic disease. We evaluated the feasibility and safety of sampling portal venous blood via endoscopic ultrasound (EUS) to count portal venous circulating tumor cells (CTCs), compared with paired peripheral CTCs, in patients with pancreaticobiliary cancers (PBCs). METHODS In a single-center cohort study, we evaluated 18 patients with suspected PBCs. Under EUS guidance, a 19-gauge EUS fine needle was advanced transhepatically into the portal vein and as many as four 7.5-mL aliquots of blood were aspirated. Paired peripheral blood samples were obtained. Epithelial-derived CTCs were sorted magnetically based on expression of epithelial cell adhesion molecules; only those with a proper morphology and found to be CD45 negative and positive for cytokeratins 8, 18, and/ or 19 and 4′,6-diamidino-2-phenylindole were considered to be CTCs. For 5 samples, CTCs also were isolated by flow cytometry and based on CD45 depletion. ImageStream was used to determine the relative protein levels of P16, SMAD4, and P53. DNA was extracted from CTCs for sequencing of select KRAS codons. RESULTS There were no complications from portal vein blood acquisition. We detected CTCs in portal vein samples from all 18 patients (100%) vs peripheral blood samples from only 4 patients (22.2%). Patients with confirmed PBCs had a mean of 118.4 ± 36.8 CTCs/7.5 mL portal vein blood, compared with a mean of 0.8 ± 0.4 CTCs/7.5 mL peripheral blood (P < .01). The 9 patients with nonmetastatic, resectable, or borderline-resectable PBCs had a mean of 83.2 CTCs/7.5 mL portal vein blood (median, 62.0 CTCs/7.5 mL portal vein blood). In a selected patient, portal vein CTCs were found to carry the same mutations as those detected in a metastatic lymph node and expressed similar levels of P16, SMAD4, and P53 proteins. CONCLUSIONS It is feasible and safe to collect portal venous blood from patients undergoing EUS. We identified CTCs in all portal vein blood samples from patients with PBCs, but less than 25% of peripheral blood samples. Portal vein CTCs can be used for molecular characterization of PBCs and share features of metastatic tissue. This technique might be used to study the pathogenesis and progression of PBCs, as well as a diagnostic or prognostic tool to stratify risk of cancer recurrence or developing metastases.

TET-catalyzed 5-hydroxymethylcytosine regulates gene expression in differentiating colonocytes and colon cancer.

The formation of differentiated cell types from pluripotent progenitors involves epigenetic regulation of gene expression. DNA hydroxymethylation results from the enzymatic oxidation of 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) by the ten-eleven translocation (TET) 5-mC dioxygenase enzymes. Previous work has mapped changes in 5-mC during differentiation of intestinal stem cells. However, whether or not 5-hmC regulates colonocyte differentiation is unknown. Here we show that 5-hmC regulates gene expression during colonocyte differentiation and controls gene expression in human colon cancers. Genome-wide profiling of 5-hmC during in vitro colonic differentiation demonstrated that 5-hmC is gained at highly expressed and induced genes and is associated with intestinal transcription factor binding sites, including those for HNF4A and CDX2. TET1 induction occurred during differentiation, and TET1 knockdown altered gene expression and inhibited barrier formation of colonocytes. We find that the 5-hmC distribution in primary human colonocytes parallels the distribution found in differentiated cells in vitro, and that gene-specific 5-hmC changes in human colon cancers are directly correlated with changes in gene expression. Our results support a model in which 5-hmC regulates differentiation of adult human intestine and 5-hmC alterations contribute to the disrupted gene expression in colon cancer.

Characterization of T-cell Receptor Repertoire in Inflamed Tissues of Patients with Crohn's Disease Through Deep Sequencing

Background:Intestinal tissues of patients with Crohns disease (CD) contain expanded populations of T cells which are believed to mediate inflammation. We performed a detailed characterization of these T-cell repertoires. Methods:We obtained biopsies from the neoterminal ileum of 12 patients undergoing evaluation for postoperative recurrent CD and 4 individuals with normal terminal ileum and no history of inflammatory bowel disease (controls). Samples of diseased terminal ileum were obtained from 5 patients undergoing surgery for stricturing or penetrating CD. Total RNA was extracted from tissues and peripheral blood mononuclear cells, and cDNAs were generated. We used next-generation sequencing to characterize T-cell receptor (TCR)-&agr; and TCR-&bgr; cDNAs in ileal mucosal tissue and matched peripheral blood mononuclear cells of 17 patients with CD to identify oligoclonal expansions of T-cell populations associated with CD. Results:TCR diversity in mucosal tissue was significantly lower than that of matched peripheral blood mononuclear cells, indicating expansion of certain T-cell populations in inflamed intestinal tissue. A single TCR-&bgr; clonotype, CASSWTNGEQYF (TRBV10-1-TRBJ2-7), was enriched at a frequency of 7.0% to 28.9% in the neoterminal ileum of 4 of 12 patients with recurrent CD. The abundance of this clonotype significantly correlated with the severity of disease recurrence, based on Rutgeerts score (P = 0.015). Conclusions:Specific populations of T cells are expanded in the inflamed intestinal mucosa of patients with CD; their abundance correlates with severity of disease recurrence. Studies of these T cells could provide information about mechanisms of CD pathogenesis. Deep TCR sequencing is a powerful tool that rapidly provides in-depth, real-time assessment of the T-cell repertoire.

The potential for medical therapy to reduce the risk of colorectal cancer and optimize surveillance in inflammatory bowel disease.

It has been proposed that effective disease control through abrogation of inflammation in IBD may also reduce CRC risk in these individual patients. This article summarizes the potential for medical therapy to reduce the risk of CRC via primary and secondary prevention, and offers practical ways in which a goal of mucosal improvement or healing may be incorporated into clinical practice.

Endoscopic Ultrasound (EUS)-Guided Pancreatic Duct Drainage: The Basics of When and How to Perform EUS-Guided Pancreatic Duct Interventions

Despite the advances in endoscopy, endoscopic ultrasound-guided pancreatic duct drainage (EUS-PDD) remains a technically challenging procedure. Technical success rates are greater than 70%; however, the average rate of adverse events is nearly 20%, which increases to 55% when stent migration is included. Until recently, a significant difficulty with this technique was the absence of dedicated devices. Proper patient selection is of utmost importance, and EUS-PDD should be reserved for patients who have failed endoscopic retrograde pancreatography. Furthermore, EUS-PDD must be performed by experienced endoscopists who are familiar with the technique. The most common indications include chronic pancreatitis induced strictures and stones, disconnected pancreatic ducts, inaccessible ampulla, and post-surgical altered anatomy. This manuscript will review the accessories used, techniques employed, and published literature reporting outcomes as well as adverse events regarding EUS-PDD.

New Scopes, New Accessories, New Stents for Interventional Endoscopic Ultrasound.

Technological advances have rapidly expanded the therapeutic potential of endoscopic ultrasound (EUS). Innovations in stent technology; directed adjunctive therapy for pancreatic tumors, including radiofrequency ablation and fiducial marker placement; advanced imaging modalities, including needle-based confocal laser endomicroscopy; and new echoendoscopes, such as the forward-viewing linear echoendoscope, are emerging as safe and effective tools and devices for providing a broad range of treatments and therapies previously not thought possible. In this review, we summarize and discuss the new echoendoscopes, accessories, and stents for interventional EUS and highlight the recent literature on technical and therapeutic efficacy. The therapeutic role and indications for EUS are rapidly evolving well beyond its current limits as new EUS-specific designed tools are designed, and ultimately, should help achieve the goal of improving patient outcomes.

Use of volumetric laser endomicroscopy for dysplasia detection at the gastroesophageal junction and gastric cardia

AIM To determine specific volumetric laser endomicroscopy (VLE) imaging features associated with neoplasia at the gastroesophageal junction (GEJ) and gastric cardia. METHODS During esophagogastroduodenoscopy for patients with known or suspected Barrett’s esophagus, VLE was performed before biopsies were taken at endoscopists’ discretion. The gastric cardia was examined on VLE scan from the GEJ (marked by top of gastric folds) to 1 cm distal from the GEJ. The NinePoints VLE console was used to analyze scan segments for characteristics previously found to correlate with normal or abnormal mucosa. Glands were counted individually. Imaging features identified on VLE scan were correlated with biopsy results from the GEJ and cardia region. RESULTS This study included 34 cases. Features characteristic of the gastric cardia (gastric rugae, gastric pit architecture, poor penetration) were observed in all (100%) scans. Loss of classic gastric pit architecture was common and there was no difference between those with neoplasia and without (100% vs 74%, P = NS). The abnormal VLE feature of irregular surface was more often seen in patients with neoplasia than those without (100% vs 18%, P < 0.0001), as was heterogeneous scattering (86% vs 41%, P < 0.005) and presence of anomalous glands (100% vs 59%, P < 0.05). The number of anomalous glands did not differ between individual histologic subgroups (ANOVA, P = NS). CONCLUSION The transition from esophagus to gastric cardia is reliably identified on VLE. Histologically abnormal cardia mucosa produces abnormal VLE features. Optical coherence tomography algorithms can be expanded for use at the GEJ/cardia.

Use of Serum Infliximab Level Prior to Cyclosporine Salvage Therapy in Severe Ulcerative Colitis

Medical treatment options for severe, steroid refractory ulcerative colitis (UC) include infliximab (IFX) or cyclosporine (CSA), but general consensus has been that both agents should not be used together or even successively. We report a case of a 17-year-old male with severe UC refractory to IV steroids with successful sequential salvage therapy guided by serum IFX level. After primary lack of response to IFX, an undetectable serum IFX level and elevated IFX antibodies were followed by immediate transition to IV CSA. This case demonstrates the possibility of therapeutic drug monitoring of IFX levels when calculating the risk/benefit ratio for patients with steroid-refractory UC failing primary salvage therapy.

Efficacy, Durability, and Safety of Complete Endoscopic Mucosal Resection of Barrett Esophagus: A Systematic Review and Meta-Analysis.

Goals: To report the rate of eradication and recurrence of both neoplasia and intestinal mucosa and the rate of adverse events for complete endoscopic resection (CER) of Barrett esophagus (BE). Background: There is limited composite data on the clinical efficacy of CER of BE with high-grade dysplasia or neoplasia. Study: We performed a systematic review and meta-analysis of cohort studies that reported the clinical outcome of patients with BE who underwent CER and had at least 15-month follow-up after the time of elimination of BE. Main outcome of interests were pooled estimated rates of complete eradication of intestinal metaplasia and neoplasia, recurrence of intestinal metaplasia and neoplasia, and incidence of esophageal stricture, bleeding, and perforation. Results: We identified 8 studies reporting on 676 patients (high-grade dysplasia 54%) that met our criteria. Pooled estimated rates of complete eradication of intestinal metaplasia and complete eradication of intestinal neoplasia were 85.0% [95% confidence interval (CI), 79.4%-89.2%] and 96.6% (95% CI, 94.0%-98.1%), respectively, and rates of recurrence of intestinal metaplasia and recurrence of intestinal neoplasia were 15.7% (95% CI, 8.0%-28.4%) and 5.8% (95% CI, 3.9%-8.6%), respectively. Estimated incidences of adverse events were stricture 37.4 (95% CI, 24.4%-52.6%), bleeding 7.9% (95% CI, 4.4%-13.8%) and perforation 2.3% (95% CI, 1.3%-4.1%). Conclusions: CER achieves an 85% complete eradication rate of BE with recurrent rate of neoplasia of 6%. Estimated rate of postprocedural stricture was 37.4%. On the basis of this high rate of adverse events and significant heterogeneity in the studies included, the present meta-analysis cannot endorse CER as sole therapy for BE.