A transient wave of BMP signaling in the retina is necessary for Müller glial differentiation.

The primary glial cells in the retina, the Müller glia, differentiate from retinal progenitors in the first postnatal week. CNTF/LIF/STAT3 signaling has been shown to promote their differentiation; however, another key glial differentiation signal, BMP, has not been examined during this period of Müller glial differentiation. In the course of our analysis of the BMP signaling pathway, we observed a transient wave of Smad1/5/8 signaling in the inner nuclear layer at the end of the first postnatal week, from postnatal day (P) 5 to P9, after the end of neurogenesis. To determine the function of this transient wave, we blocked BMP signaling during this period in vitro or in vivo, using either a BMP receptor antagonist or noggin (Nog). Either treatment leads to a reduction in expression of the Müller glia-specific genes Rlbp1 and Glul, and the failure of many of the Müller glia to repress the bipolar/photoreceptor gene Otx2. These changes in normal Müller glial differentiation result in permanent disruption of the retina, including defects in the outer limiting membrane, rosette formation and a reduction in functional acuity. Our results thus show that Müller glia require a transient BMP signal at the end of neurogenesis to fully repress the neural gene expression program and to promote glial gene expression.

Transgenic expression of the proneural transcription factor Ascl1 in Müller glia stimulates retinal regeneration in young mice.

Müller glial cells are the source of retinal regeneration in fish and birds; although this process is efficient in fish, it is less so in birds and very limited in mammals. It has been proposed that factors necessary for providing neurogenic competence to Müller glia in fish and birds after retinal injury are not expressed in mammals. One such factor, the proneural transcription factor Ascl1, is necessary for retinal regeneration in fish but is not expressed after retinal damage in mice. We previously reported that forced expression of Ascl1 in vitro reprograms Müller glia to a neurogenic state. We now test whether forced expression of Ascl1 in mouse Müller glia in vivo stimulates their capacity for retinal regeneration. We find that transgenic expression of Ascl1 in adult Müller glia in undamaged retina does not overtly affect their phenotype; however, when the retina is damaged, the Ascl1-expressing glia initiate a response that resembles the early stages of retinal regeneration in zebrafish. The reaction to injury is even more pronounced in Müller glia in young mice, where the Ascl1-expressing Müller glia give rise to amacrine and bipolar cells and photoreceptors. DNaseI-seq analysis of the retina and Müller glia shows progressive reduction in accessibility of progenitor gene cis-regulatory regions consistent with the reduction in their reprogramming. These results show that at least one of the differences between mammal and fish Müller glia that bears on their difference in regenerative potential is the proneural transcription factor Ascl1.

Ezh2 maintains retinal progenitor proliferation, transcriptional integrity, and the timing of late differentiation.

Epigenetic regulation, including histone modification, is a critical component of gene regulation, although precisely how this contributes to the development of complex tissues such as the neural retina is still being explored. We show that during retinal development in mouse, there are dynamic patterns of expression of the polycomb repressive complex 2 (PRC2) catalytic subunit EZH2 in retinal progenitors and some differentiated cells, as well as dynamic changes in the histone modification H3K27me3. Using conditional knockout of Ezh2 using either Pax6-αCre or Six3-Cre, we find selective reduction in postnatal retinal progenitor proliferation, disruption of retinal lamination, and enhanced differentiation of several late born cell types in the early postnatal retina, including photoreceptors and Müller glia, which are ultimately increased in number and become reactive. RNA-seq identifies many non-retinal genes upregulated with loss of Ezh2, including multiple Hox genes and the cell cycle regulator Cdkn2a, which are established targets of EZH2-mediated repression. ChIP analysis confirms loss of the H3K27me3 modification at these loci. Similar gene upregulation is observed in retinal explants treated with an EZH2 chemical inhibitor. There is considerable overlap with EZH2-regulated genes reported in non-neural tissues, suggesting that EZH2 can regulate similar genes in multiple lineages. Our findings reveal a conserved role for EZH2 in constraining the expression of potent developmental regulators to maintain lineage integrity and retinal progenitor proliferation, as well as regulating the timing of late differentiation.

ASCL1 reprograms mouse Muller glia into neurogenic retinal progenitors.

Non-mammalian vertebrates have a robust ability to regenerate injured retinal neurons from Müller glia (MG) that activate the gene encoding the proneural factor Achaete-scute homolog 1 (Ascl1; also known as Mash1 in mammals) and de-differentiate into progenitor cells. By contrast, mammalian MG have a limited regenerative response and fail to upregulate Ascl1 after injury. To test whether ASCL1 could restore neurogenic potential to mammalian MG, we overexpressed ASCL1 in dissociated mouse MG cultures and intact retinal explants. ASCL1-infected MG upregulated retinal progenitor-specific genes and downregulated glial genes. Furthermore, ASCL1 remodeled the chromatin at its targets from a repressive to an active configuration. MG-derived progenitors differentiated into cells that exhibited neuronal morphologies, expressed retinal subtype-specific neuronal markers and displayed neuron-like physiological responses. These results indicate that a single transcription factor, ASCL1, can induce a neurogenic state in mature MG.

Efficacy and safety of therapeutic ERCP in patients with cirrhosis: a large multicenter study.

BACKGROUND AND AIMS: Patients with cirrhosis may be less than optimal candidates for ERCP because of underlying ascites, coagulopathy, encephalopathy, and other problems. Although the risks of surgery in patients with cirrhosis are well known, few data are available regarding ERCP in patients with cirrhosis. We performed a retrospective, multicenter study of ERCP in patients with cirrhosis to evaluate outcomes, efficacy, and safety. METHODS: Multicenter retrospective study. RESULTS: A total of 538 ERCP procedures were performed on 328 patients with cirrhosis. A total of 229 patients had Child-Pugh (CP) class A, 229 patients had CP class B, and 80 patients had CP class C. Thrombocytopenia and coagulopathy were corrected before ERCP. The 30-day, procedure-related adverse events included post-ERCP pancreatitis (n = 25, 4.6%: 21 mild, 3 moderate, 1 severe), hemorrhage (n = 6, 1.1%), cholangitis (n = 15, 2.8%), perforation (n = 2, 0.4%), aspiration pneumonia (n = 5, 0.9%), bile leakage (n = 1, 0.2%), cholecystitis (n = 1, 0.2%), and death (n = 1, 0.2%). There was a higher incidence of adverse events in patients with CP class B and C disease when compared with those with CP class A disease (11.4%, 11.3%, and 6.1%, respectively; P = .048). There was no correlation between the risk of significant hemorrhage and the presence of coagulopathy or CP class, even in those who underwent a sphincterotomy. The presence of poorly controlled encephalopathy correlated with a higher overall adverse event rate (P = .003). Sub-analysis revealed that patients without primary sclerosing cholangitis had a significantly higher overall rate of adverse events, pancreatitis, bleeding, and cardiopulmonary adverse events after ERCP when compared with those with primary sclerosing cholangitis. CONCLUSIONS: Our study was performed on a large series of patients with cirrhosis undergoing ERCP. Overall, the adverse events seen in patients with cirrhosis are similar to those seen in the general population of patients undergoing ERCP, although patients with CP classes B and C have higher adverse event rates compared with those with CP class A. Patients with cirrhosis without primary sclerosing cholangitis had significantly greater adverse event rates when compared with patients with primary sclerosing cholangitis.

Elevated Serum Bilirubin Level Correlates With the Development of Cholangiocarcinoma, Subsequent Liver Transplantation, and Death in Patients With Primary Sclerosing Cholangitis.

INTRODUCTION: Predicting the clinical course of primary sclerosing cholangitis (PSC) is difficult. There are currently a paucity of studies evaluating serum chemistries as predictors of conventional clinical endpoints. The purpose of this study was to prognosticate key clinical endpoints in patients with PSC who had elevated serum liver chemistries at the time of their initial presentation. METHODS: We performed a retrospective cohort study of PSC patients at our institution. The aim of our study was to determine the association between elevated liver chemistries at initial presentation-bilirubin, alanine transaminase, aspartate transaminase, or alkaline phosphatase-with a primary outcome of either cholangiocarcinoma, liver transplantation, death, or composite of the 3. The secondary endpoints examined were development of severe biliary ductal disease and need for biliary stent placement. RESULTS: Eighty-one PSC patients (61 males and 20 females) were included in this study. By univariate analysis, there was a significant association between initial bilirubin elevation >2x the upper limit of normal (ULN) and death (P<0.009). Multivariate regression analysis revealed that an elevated initial serum total bilirubin >2xULN (P<0.017) significantly predicted the composite endpoint. By univariate analysis of pre-endoscopic retrograde cholangiopancreatography labs, serum bilirubin level elevation >2xULN showed an association with severity of biliary ductal disease (P<0.0001). A logistic regression of outcome variables also proved that >2xULN serum bilirubin levels predicted the ductal disease severity (P<0.0001). CONCLUSIONS: An initial elevation of serum total bilirubin >2xULN in PSC patients correlates positively with the development of cholangiocarcinoma, subsequent liver transplantation, and death. Elevated bilirubin also correlates positively with the severity of cholangiographic findings.

Clinical Outcomes, Efficacy, and Adverse Events in Patients Undergoing Esophageal Stent Placement for Benign Indications: A Large Multicenter Study.

INTRODUCTION: Esophageal stents are commonly used to treat benign esophageal conditions including refractory benign esophageal strictures, anastomotic strictures, fistulae, perforations and anastomotic leaks. Data on outcomes in these settings remain limited. METHODS: We performed a retrospective multicenter study of patients who underwent fully or partially covered self-expandable stent placement for benign esophageal diseases. Esophageal stent placements were performed for the following indications: (1) benign refractory esophageal strictures, (2) surgical anastomotic strictures, (3) esophageal perforations, (4) esophageal fistulae, and (5) surgical anastomotic leaks. RESULTS: A total of 70 patients underwent esophageal stent placement for benign esophageal conditions. A total of 114 separate procedures were performed. The most common indication for esophageal stent placement was refractory benign esophageal stricture (48.2%). Global treatment success rate was 55.7%. Treatment success rate was 33.3% in refractory benign strictures, 23.1% in anastomotic strictures, 100% in perforations, 71.4% in fistulae, and 80% in anastomotic leaks. Stent migration was noted in 28 of 70 patients (40%), most commonly seen in refractory benign strictures. CONCLUSIONS: This is one of the largest studies to date of esophageal stents to treat benign esophageal diseases. Success rates are lowest in benign esophageal strictures. These patients have few other options beyond chronic dilations, feeding tubes, and surgery, and fully covered self-expandable metallic stent give patients a chance to have their problem fixed endoscopically and still eat by mouth. Perforations, fistulas, and leaks respond very well to esophageal stenting, and stenting should be considered as a first-line therapy in these settings.

Outcomes of Next-Day Versus Non-next-Day Colonoscopy After an Initial Inadequate Bowel Preparation.

BACKGROUND: Inadequate bowel preparation is the most common cause of failed colonoscopy, and repeat failure occurs in more than 20 % of follow-up attempts. Limited data suggest that next-day follow-up may reduce the risk for repeat inadequate preparation. OBJECTIVE: Evaluate differences in prep quality with next-day follow-up after initial inadequate preparation. DESIGN: Retrospective study. SETTING: Academic center. PATIENTS: Outpatient screening and surveillance colonoscopies between 7/2002 and 6/2007. INTERVENTION: Comparison of next-day versus any other day ("non-next-day") repeat colonoscopy outcomes. MAIN OUTCOME MEASUREMENTS: Aronchick scale, polyp and adenoma detection rates. RESULTS: Of 20,798 initial colonoscopies, 857 (4.1 %) had inadequate preparation. 460 (54 %) were lost to follow-up. One hundred and fourteen (13 %) had next-day and 283 (33 %) had non-next-day colonoscopy with mean follow-up of 8.8 months. On follow-up examination, 29.8 % of next-day and 23.3 % of non-next-day colonoscopies had inadequate bowel preparation (p = 0.48). The adenoma detection rate for the next-day group improved from 3.5 to 38.6 % on follow-up, compared to 20.5 and 36.8 % in the non-next-day group. There was no significant difference between groups in detection of total adenoma (p = 0.73) or advanced adenomas (p = 0.20) on follow-up examinations. LIMITATIONS: Retrospective design, differences in baseline colonoscopy characteristics. CONCLUSION: The results confirm the need for repeat examination after a colonoscopy with inadequate bowel prep, as there was substantial increase in adenoma detection on follow-up. There were no differences in outcomes between next-day versus non-next-day colonoscopy. These data support repeating after inadequate colonoscopy within 1 year as convenient for patient and physician.

Eosinophilic esophagitis in adults is associated with IgG4 and not mediated by IgE.

BACKGROUND & AIMS: Eosinophilic esophagitis is usually triggered by foods, by unclear mechanisms. We evaluated the roles of IgE and IgG4 in the development of eosinophilic esophagitis. METHODS: We performed a prospective, randomized, double-blind, placebo-controlled trial of adults with eosinophilic esophagitis given an antibody against IgE (omalizumab, n = 16) or placebo (n = 14) every 2-4 weeks for 16 weeks, based on weight and serum level of IgE. Endoscopy was performed, esophageal biopsy specimens were collected, and symptoms were assessed at baseline and at 16 weeks. Maximum numbers of eosinophils/high-power field were determined. Homogenates of esophageal biopsy specimens from 11 subjects with eosinophilic esophagitis and 8 without (controls) were assessed for IgM, IgA, and IgG subclasses. In a retrospective analysis, we performed immunofluorescence analysis of IgG4 in fixed esophageal tissues from 2 patients with eosinophilic esophagitis who underwent esophagectomy and 47 consecutive autopsies (controls). We also performed immunofluorescence analysis of IgG4 in esophageal mucosal biopsy specimens from 24 subjects with eosinophilic esophagitis and 9 without (controls). Finally, sera were collected from 15 subjects with eosinophilic esophagitis and from 41 without (controls), and assayed for total and food-reactive IgG4. RESULTS: Omalizumab did not alter symptoms of eosinophilic esophagitis or eosinophil counts in biopsy samples compared with placebo. Homogenates of esophageal tissues from patients with eosinophilic esophagitis had a 45-fold increase in IgG4 compared with controls (P < 3 × 10(-5)), but no significant increases in other IgG subclasses, IgM, or IgA. Sparse stromal deposits resembling immune complexes were found in 2 of 5 eosinophilic esophagitis biopsy specimens based on ultrastructural analysis. Esophagectomy samples from 2 patients with eosinophilic esophagitis contained 180 and 300 IgG4 plasma cells/maximal high-power field, mainly in the deep lamina propria; these levels were greater than in tissues from controls. Fibrosis essentially was exclusive to the lamina propria. Granular extracellular IgG4 was detected in biopsy specimens from 21 of 24 patients with eosinophilic esophagitis, but in none of the specimens from 9 controls (P = 6 × 10(-6)). The total serum level of IgG4 increased only slightly in patients with eosinophilic esophagitis, compared with controls. Subjects with eosinophilic esophagitis had increased serum levels of IgG4 that reacted with milk, wheat, egg, and nuts-the 4 foods that most commonly trigger this condition (P ≤ 3 × 10(-4) for each food). CONCLUSIONS: In a prospective trial, omalizumab did not reduce symptoms of eosinophilic esophagitis or tissue eosinophil counts compared with placebo. This finding, along with observed granular deposits of IgG4, abundant IgG4-containing plasma cells, and serum levels of IgG4 reactive to specific foods, indicate that, in adults, eosinophilic esophagitis is IgG4-associated, and not an IgE-induced allergy. ClinicalTrials.gov number: NCT 00123630.

Cholangiocarcinoma and high-grade dysplasia in young patients with primary sclerosing cholangitis.

INTRODUCTION: Cholangiocarcinoma (CCA) is very often an adulthood disease with primary sclerosing cholangitis (PSC) as one of the risk factors. It is rarely seen in the pediatric population, and when it is diagnosed before adulthood, it can be associated with PSC as well as HIV infection, biliary atresia, radiation therapy, and choledochal cyst. Although there have been some case reports of pediatric CCA, cases of childhood CCA associated with PSC are still relatively rare. AIM: To describe the clinical and pathologic features of CCA in pediatric patients with previously diagnosed PSC. METHODS: Retrospective study RESULTS: Four patients with PSC (age range 15-18, mean 17 years) were included in this study. All patients underwent ERCP for diagnosis. Tissue samples obtained included routine cytology and FISH. ERCP was used to target sites for tissue acquisition in all patients. 3/4 of patients have inflammatory bowel disease (two Crohn's disease and one ulcerative colitis). Alkaline phosphatase was elevated in 3/4 patients, aspartate aminotransferase/alanine aminotransferase were elevated in 2/4 patients, and total bilirubin/direct bilirubin were elevated in 2/4 patients. 4/4 patients had positive FISH studies, and 3/4 patients had brush cytology concerning for CCA. 2/4 patients received chemotherapy, one patient underwent orthotopic liver transplant, and one patient underwent Whipple procedure. Two patients died soon after being diagnosed. CONCLUSIONS: Young patients with PSC can develop CCA. This finding has implications for both screening and surveillance for cancer in pediatric patients with PSC.

Stage of hilar cholangiocarcinoma predicts recurrence of biliary obstruction in patients with metal stents.

BACKGROUND & AIMS: Most patients with hilar cholangiocarcinomas present with unresectable tumors, so only palliative biliary drainage with self-expanding metal stents (SEMS) is possible. Stents eventually cease to function because of tumor overgrowth and/or other causes, so it is important to identify factors that affect stent patency and failure. We examined the patency of endoscopically placed SEMS in patients with hilar cholangiocarcinoma and factors associated with patency. METHODS: We performed a retrospective study of 120 consecutive patients (mean age, 67 ± 14.6 years; 74 male) who presented with obstructive jaundice from hilar cholangiocarcinoma and underwent bilateral SEMS from September 2006 through April 2012 at 2 US tertiary medical centers. We collected data on patient demographics and survival, success of stent placement and function, and immediate adverse events. The primary outcome was duration of stent patency (time from insertion to failure). RESULTS: Thirty-eight patients had stage 1 hilar cholangiocarcinomas, 45 had stage 2, 12 had stage 3, and 25 had stage 4. The median length of the hilar stricture was 9 mm (range, 8-50 mm). The stent was successfully passaged across the stricture in all patients and was functional in 115; its median length was 8 mm (range, 8-10 mm), and diameter was 80 mm (range, 60-100 mm). Fourteen patients had immediate adverse events, including perforation (n = 2), bleeding (n = 2), pancreatitis (n = 9), and cholangitis (n = 1). Median survival was 17 weeks (range, 1-211 weeks), and 50 patients had stent occlusion. On Kaplan-Meier analysis, the median time from stent placement to occlusion was 17 weeks (range, 1-104 weeks). More patients with stage 3 or 4 tumors (64%) had SEMS occlusion than patients with stage 1 or 2 tumors (28%) in univariate analysis (P = .017). In multivariate analysis, only cancer stage was independently and significantly associated with patency (P = .006; hazard ratio, 2.77); age, sex, length of stricture, and SEMS diameter and length were not. CONCLUSIONS: The cumulative patency of bilateral SEMS for hilar cholangiocarcinoma significantly decreases as tumor stage increases. Age, sex, length of stricture, and SEMS diameter and length are not associated with SEMS patency.

Self-expanding stent effects on radiation dosimetry in esophageal cancer.

It is the purpose of this study to evaluate how self-expanding stents (SESs) affect esophageal cancer radiation planning target volumes (PTVs) and dose delivered to surrounding organs at risk (OARs). Ten patients were evaluated, for whom a SES was placed before radiation. A computed tomography (CT) scan obtained before stent placement was fused to the post-stent CT simulation scan. Three methods were used to represent pre-stent PTVs: 1) image fusion (IF), 2) volume approximation (VA), and 3) diameter approximation (DA). PTVs and OARs were contoured per RTOG 1010 protocol using Eclipse Treatment Planning software. Post-stent dosimetry for each patient was compared to approximated pre-stent dosimetry. For each of the three pre-stent approximations (IF, VA, and DA), the mean lung and liver doses and the estimated percentages of lung volumes receiving 5 Gy, 10 Gy, 20 Gy, and 30 Gy, and heart volumes receiving 40 Gy were significantly lower (p-values < 0.02) than those estimated in the post-stent treatment plans. The lung V5, lung V10, and heart V40 constraints were achieved more often using our pre-stent approximations. Esophageal SES placement increases the dose delivered to the lungs, heart, and liver. This may have clinical importance, especially when the dose-volume constraints are near the recommended thresholds, as was the case for lung V5, lung V10, and heart V40. While stents have established benefits for treating patients with significant dysphagia, physicians considering stent placement and radiation therapy must realize the effects stents can have on the dosimetry.

A competency-based approach to expanding the cancer care workforce part III--improving cancer pain and palliative care competency.

As part of an effort to address shortages in the cancer workforce, C-Change developed competency standards and logic model-driven implementation tools for strengthening the cancer knowledge and skills of non-oncology health professionals. These standards and tools were applied by four diverse grant programs to yield gains in the management of pain and palliative care, thereby improving the quality of care for individuals experiencing or recovering from cancer treatment. The results from the four grant sites and tools used to achieve them are described in this article.

Developmental changes in the accessible chromatin, transcriptome and Ascl1-binding correlate with the loss in Müller Glial regenerative potential.

Diseases and damage to the retina lead to losses in retinal neurons and eventual visual impairment. Although the mammalian retina has no inherent regenerative capabilities, fish have robust regeneration from Müller glia (MG). Recently, we have shown that driving expression of Ascl1 in adult mouse MG stimulates neural regeneration. The regeneration observed in the mouse is limited in the variety of neurons that can be derived from MG; Ascl1-expressing MG primarily generate bipolar cells. To better understand the limits of MG-based regeneration in mouse retinas, we used ATAC- and RNA-seq to compare newborn progenitors, immature MG (P8-P12), and mature MG. Our analysis demonstrated developmental differences in gene expression and accessible chromatin between progenitors and MG, primarily in neurogenic genes. Overexpression of Ascl1 is more effective in reprogramming immature MG, than mature MG, consistent with a more progenitor-like epigenetic landscape in the former. We also used ASCL1 ChIPseq to compare the differences in ASCL1 binding in progenitors and reprogrammed MG. We find that bipolar-specific accessible regions are more frequently linked to bHLH motifs and ASCL1 binding. Overall, our analysis indicates a loss of neurogenic gene expression and motif accessibility during glial maturation that may prevent efficient reprogramming.

Insufflation with carbon dioxide reduces pneumoperitoneum after percutaneous endoscopic gastrostomy (PEG): a randomized controlled trial.

BACKGROUND AND STUDY AIMS: Pneumoperitoneum following PEG placement has been reported in up to 60 % of cases, and while usually benign and self-limited, it can lead to evaluation for suspected perforation. This study was designed to determine whether using CO2 compared to ambient air for insufflation during PEG reduces post-procedure pneumoperitoneum. PATIENTS AND METHODS: Prospective, double-blind, randomized trial of 35 consecutive patients undergoing PEG at a single academic medical center. Patients were randomized to insufflation with CO2 or ambient air. The primary outcome was pneumoperitoneum determined by left-lateral decubitus abdominal x-rays 30 minutes after PEG placement. Secondary endpoints included abdominal distention, pain, and bloating. RESULTS: PEG was successfully placed in 17 patients using CO2 and 18 patients using ambient air. Three patients in each arm were unable or declined to have x-rays completed and were excluded. Pneumoperitoneum was identified in 2/14 (14.3 %) using CO2 and 8/15 (53.3 %) using ambient air (P = 0.05). There was no significant difference in abdominal distention, visual analog scale (VAS) scores for pain or bloating between CO2 and ambient air. CONCLUSION: Utilizing CO2 significantly reduces the frequency of post-procedural pneumoperitoneum compared to use of ambient air during PEG placement, with no difference in waist circumference, pain or bloating between CO2 and ambient air. CO2 appears to be safe and effective for use and may be the insufflation agent of choice during PEG.

"Cat Scratch Colon" and Cecal Barotrauma perforation during colonoscopy using CO2 insufflation.

Cecal perforation due to barotrauma is an increasingly recognized complication of colonoscopy when using room air for insufflation. CO2 is increasingly being utilized for insufflation due to more rapid absorption compared to ambient air and results in reduced post-procedural pain and flatulence. Use of CO2 is thought to protect against barotrauma injury, and use of CO2 during endoscopy has not previously been reported to cause barotrauma perforation during colonoscopy. We present a case of cecal perforation secondary to barotrauma during routine screening colonoscopy with CO2.