Identification of PRMT5 as a therapeutic target in cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma (CCA) is a very difficult-to-treat cancer. Chemotherapies are little effective and response to immune checkpoint inhibitors is limited. Therefore, new therapeutic strategies need to be identified. OBJECTIVE: We characterised the enzyme protein arginine-methyltransferase 5 (PRMT5) as a novel therapeutic target in CCA. DESIGN: We evaluated the expression of PRMT5, its functional partner MEP50 and methylthioadenosine phosphorylase (MTAP)-an enzyme that modulates the sensitivity of PRMT5 to pharmacological inhibitors-in human CCA tissues. PRMT5-targeting drugs, currently tested in clinical trials for other malignancies, were assessed in human CCA cell lines and organoids, as well as in two immunocompetent CCA mouse models. Transcriptomic, proteomic and functional analyses were performed to explore the underlying antitumoural mechanisms. RESULTS: PRMT5 and MEP50 proteins were correlatively overexpressed in most CCA tissues. MTAP was absent in 25% of intrahepatic CCA. PRMT5-targeting drugs markedly inhibited CCA cell proliferation, synergising with cisplatin and gemcitabine and hindered the growth of cholangiocarcinoma organoids. PRMT5 inhibition blunted the expression of oncogenic genes involved in chromatin remodelling and DNA repair, consistently inducing the formation of RNA loops and promoting DNA damage. Treatment with PRMT5-targeting drugs significantly restrained the growth of experimental CCA without adverse effects and concomitantly induced the recruitment of CD4 and CD8 T cells to shrinking tumourous lesions. CONCLUSION: PRMT5 and MEP50 are frequently upregulated in human CCA, and PRMT5-targeting drugs have significant antitumoural efficacy in clinically relevant CCA models. Our findings support the evaluation of PRMT5 inhibitors in clinical trials, including their combination with cytotoxic and immune therapies.

New molecular mechanisms in cholangiocarcinoma: signals triggering interleukin-6 production in tumor cells and KRAS co-opted epigenetic mediators driving metabolic reprogramming.

BACKGROUND: Cholangiocarcinoma (CCA) is still a deadly tumour. Histological and molecular aspects of thioacetamide (TAA)-induced intrahepatic CCA (iCCA) in rats mimic those of human iCCA. Carcinogenic changes and therapeutic vulnerabilities in CCA may be captured by molecular investigations in bile, where we performed bile proteomic and metabolomic analyses that help discovery yet unknown pathways relevant to human iCCA. METHODS: Cholangiocarcinogenesis was induced in rats (TAA) and mice (JnkΔhepa + CCl4 + DEN model). We performed proteomic and metabolomic analyses in bile from control and CCA-bearing rats. Differential expression was validated in rat and human CCAs. Mechanisms were addressed in human CCA cells, including Huh28-KRASG12D cells. Cell signaling, growth, gene regulation and [U-13C]-D-glucose-serine fluxomics analyses were performed. In vivo studies were performed in the clinically-relevant iCCA mouse model. RESULTS: Pathways related to inflammation, oxidative stress and glucose metabolism were identified by proteomic analysis. Oxidative stress and high amounts of the oncogenesis-supporting amino acids serine and glycine were discovered by metabolomic studies. Most relevant hits were confirmed in rat and human CCAs (TCGA). Activation of interleukin-6 (IL6) and epidermal growth factor receptor (EGFR) pathways, and key genes in cancer-related glucose metabolic reprogramming, were validated in TAA-CCAs. In TAA-CCAs, G9a, an epigenetic pro-tumorigenic writer, was also increased. We show that EGFR signaling and mutant KRASG12D can both activate IL6 production in CCA cells. Furthermore, phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in serine-glycine pathway, was upregulated in human iCCA correlating with G9a expression. In a G9a activity-dependent manner, KRASG12D promoted PHGDH expression, glucose flow towards serine synthesis, and increased CCA cell viability. KRASG12D CAA cells were more sensitive to PHGDH and G9a inhibition than controls. In mouse iCCA, G9a pharmacological targeting reduced PHGDH expression. CONCLUSIONS: In CCA, we identified new pro-tumorigenic mechanisms: Activation of EGFR signaling or KRAS mutation drives IL6 expression in tumour cells; Glucose metabolism reprogramming in iCCA includes activation of the serine-glycine pathway; Mutant KRAS drives PHGDH expression in a G9a-dependent manner; PHGDH and G9a emerge as therapeutic targets in iCCA.

HOXD8 hypermethylation as a fully sensitive and specific biomarker for biliary tract cancer detectable in tissue and bile samples.

BACKGROUND: Biliary tract cancers (BTC) are rare but highly aggressive tumours with poor prognosis, usually detected at advanced stages. Herein, we aimed at identifying BTC-specific DNA methylation alterations. METHODS: Study design included statistical power and sample size estimation. A genome-wide methylation study of an explorative cohort (50 BTC and ten matched non-tumoral tissue samples) has been performed. BTC-specific altered CpG islands were validated in over 180 samples (174 BTCs and 13 non-tumoral controls). The final biomarkers, selected by a machine-learning approach, were validated in independent tissue (18 BTCs, 14 matched non-tumoral samples) and bile (24 BTCs, five non-tumoral samples) replication series, using droplet digital PCR. RESULTS: We identified and successfully validated BTC-specific DNA methylation alterations in over 200 BTC samples. The two-biomarker panel, selected by an in-house algorithm, showed an AUC > 0.97. The best-performing biomarker (chr2:176993479-176995557), associated with HOXD8, a pivotal gene in cancer-related pathways, achieved 100% sensitivity and specificity in a new series of tissue and bile samples. CONCLUSIONS: We identified a novel fully efficient BTC biomarker, associated with HOXD8 gene, detectable both in tissue and bile by a standardised assay ready-to-use in clinical trials also including samples from non-invasive matrices.

Bile Processing Protocol for Improved Proteomic Analysis.

One of the critical issues to warrant the success of a proteome-wide analysis is sample preparation. Efficient protein extraction in the absence of interferent material is mandatory to achieve an ample proteome coverage by mass spectrometry. The study of biological fluids is always challenging due to their specific biochemical composition. However, there is increasing interest in their characterization as it will provide proteins that may advice disease setting, state, and progression. In particular, bile is proximal to liver and pancreas, and its study is especially attractive since it might provide valuable information for the clinical management of severe diseases afflicting these organs, which are at an urgent need of new biomarkers. Though previous efforts have been made to optimize protocols to analyze bile proteome, only partial descriptions were achieved due to its complex composition, where proteins represent less than 5% of the organic components. Here we describe a new method that significantly increases the bile proteome coverage while reducing by a factor of six the amount of sample required for the proteomic analysis.

Next-generation sequencing of bile cell-free DNA for the early detection of patients with malignant biliary strictures.

OBJECTIVE: Despite significant progresses in imaging and pathological evaluation, early differentiation between benign and malignant biliary strictures remains challenging. Endoscopic retrograde cholangiopancreatography (ERCP) is used to investigate biliary strictures, enabling the collection of bile. We tested the diagnostic potential of next-generation sequencing (NGS) mutational analysis of bile cell-free DNA (cfDNA). DESIGN: A prospective cohort of patients with suspicious biliary strictures (n=68) was studied. The performance of initial pathological diagnosis was compared with that of the mutational analysis of bile cfDNA collected at the time of first ERCP using an NGS panel open to clinical laboratory implementation, the Oncomine Pan-Cancer Cell-Free assay. RESULTS: An initial pathological diagnosis classified these strictures as of benign (n=26), indeterminate (n=9) or malignant (n=33) origin. Sensitivity and specificity of this diagnosis were 60% and 100%, respectively, as on follow-up 14 of the 26 and eight of the nine initially benign or indeterminate strictures resulted malignant. Sensitivity and specificity for malignancy of our NGS assay, herein named Bilemut, were 96.4% and 69.2%, respectively. Importantly, one of the four Bilemut false positives developed pancreatic cancer after extended follow-up. Remarkably, the sensitivity for malignancy of Bilemut was 100% in patients with an initial diagnosis of benign or indeterminate strictures. Analysis of 30 paired bile and tissue samples also demonstrated the superior performance of Bilemut. CONCLUSION: Implementation of Bilemut at the initial diagnostic stage for biliary strictures can significantly improve detection of malignancy, reduce delays in the clinical management of patients and assist in selecting patients for targeted therapies.

Digging deeper into bile proteome.

The analysis of biological fluids to identify proteins that may indicate a disease setting, state and progression, is an increasingly explored field. Despite the expectatives created, there are several hurdles that must be solved to reach an extensive proteome coverage using mass spectrometry, mainly due to the complex composition of the matrices. In this regard, bile is specially challenging and yet, very attractive, as a proximal fluid that might provide valuable information for the management of liver and pancreas associated diseases. Proteins account for less than 5% of bile organic components and, although optimized protocols for protein extraction have been developed, only partial descriptions of bile proteome have been achieved. In this manuscript a new procedure is described that significantly improves protein recovery from rat bile, which reduces by a factor of six the sample amount required for a typical proteomics analysis. Moreover, the number of proteins reliably identified in a single nanoLC-MS/MS run from 1 µg protein was increased by three-fold. This procedure provides a valuable resource to dig deeper into the molecular composition of bile and open new avenues to identify new hallmarks of disease such as cholangiocarcinoma, hepatocellular carcinoma and pancreatic cancer for their better clinical management.

Dual Targeting of G9a and DNA Methyltransferase-1 for the Treatment of Experimental Cholangiocarcinoma.

BACKGROUND AND AIMS: Cholangiocarcinoma (CCA) is a devastating disease often detected at advanced stages when surgery cannot be performed. Conventional and targeted systemic therapies perform poorly, and therefore effective drugs are urgently needed. Different epigenetic modifications occur in CCA and contribute to malignancy. Targeting epigenetic mechanisms may thus open therapeutic opportunities. However, modifications such as DNA and histone methylation often coexist and cooperate in carcinogenesis. We tested the therapeutic efficacy and mechanism of action of a class of dual G9a histone-methyltransferase and DNA-methyltransferase 1 (DNMT1) inhibitors. APPROACH AND RESULTS: Expression of G9a, DNMT1, and their molecular adaptor, ubiquitin-like with PHD and RING finger domains-1 (UHRF1), was determined in human CCA. We evaluated the effect of individual and combined pharmacological inhibition of G9a and DNMT1 on CCA cell growth. Our lead G9a/DNMT1 inhibitor, CM272, was tested in human CCA cells, patient-derived tumoroids and xenograft, and a mouse model of cholangiocarcinogenesis with hepatocellular deletion of c-Jun-N-terminal-kinase (Jnk)-1/2 and diethyl-nitrosamine (DEN) plus CCl4 treatment (JnkΔhepa + DEN + CCl4 mice). We found an increased and correlative expression of G9a, DNMT1, and UHRF1 in CCAs. Cotreatment with independent pharmacological inhibitors G9a and DNMT1 synergistically inhibited CCA cell growth. CM272 markedly reduced CCA cell proliferation and synergized with Cisplatin and the ERBB-targeted inhibitor, Lapatinib. CM272 inhibited CCA tumoroids and xenograft growth and significantly antagonized CCA progression in JnkΔhepa + DEN + CCl4 mice without apparent toxicity. Mechanistically, CM272 reprogrammed the tumoral metabolic transcriptome and phenotype toward a differentiated and quiescent status. CONCLUSIONS: Dual targeting of G9a and DNMT1 with epigenetic small molecule inhibitors such as CM272 is a potential strategy to treat CCA and/or enhance the efficacy of other systemic therapies.

Dual Pharmacological Targeting of HDACs and PDE5 Inhibits Liver Disease Progression in a Mouse Model of Biliary Inflammation and Fibrosis.

Liver fibrosis, a common hallmark of chronic liver disease (CLD), is characterized by the accumulation of extracellular matrix secreted by activated hepatic fibroblasts and stellate cells (HSC). Fibrogenesis involves multiple cellular and molecular processes and is intimately linked to chronic hepatic inflammation. Importantly, it has been shown to promote the loss of liver function and liver carcinogenesis. No effective therapies for liver fibrosis are currently available. We examined the anti-fibrogenic potential of a new drug (CM414) that simultaneously inhibits histone deacetylases (HDACs), more precisely HDAC1, 2, and 3 (Class I) and HDAC6 (Class II) and stimulates the cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) pathway activity through phosphodiesterase 5 (PDE5) inhibition, two mechanisms independently involved in liver fibrosis. To this end, we treated Mdr2-KO mice, a clinically relevant model of liver inflammation and fibrosis, with our dual HDAC/PDE5 inhibitor CM414. We observed a decrease in the expression of fibrogenic markers and collagen deposition, together with a marked reduction in inflammation. No signs of hepatic or systemic toxicity were recorded. Mechanistic studies in cultured human HSC and cholangiocytes (LX2 and H69 cell lines, respectively) demonstrated that CM414 inhibited pro-fibrogenic and inflammatory responses, including those triggered by transforming growth factor ß (TGFß). Our study supports the notion that simultaneous targeting of pro-inflammatory and fibrogenic mechanisms controlled by HDACs and PDE5 with a single molecule, such as CM414, can be a new disease-modifying strategy.

Epigenetics in Liver Fibrosis: Could HDACs be a Therapeutic Target?

Chronic liver diseases (CLD) represent a worldwide health problem. While CLDs may have diverse etiologies, a common pathogenic denominator is the presence of liver fibrosis. Cirrhosis, the end-stage of CLD, is characterized by extensive fibrosis and is markedly associated with the development of hepatocellular carcinoma. The most important event in hepatic fibrogenesis is the activation of hepatic stellate cells (HSC) following liver injury. Activated HSCs acquire a myofibroblast-like phenotype becoming proliferative, fibrogenic, and contractile cells. While transient activation of HSCs is part of the physiological mechanisms of tissue repair, protracted activation of a wound healing reaction leads to organ fibrosis. The phenotypic changes of activated HSCs involve epigenetic mechanisms mediated by non-coding RNAs (ncRNA) as well as by changes in DNA methylation and histone modifications. During CLD these epigenetic mechanisms become deregulated, with alterations in the expression and activity of epigenetic modulators. Here we provide an overview of the epigenetic alterations involved in fibrogenic HSCs transdifferentiation with particular focus on histones acetylation changes. We also discuss recent studies supporting the promising therapeutic potential of histone deacetylase inhibitors in liver fibrosis.

EUS is superior to secretin-enhanced cholangio-MRI to establish the etiology of idiopathic acute pancreatitis.

Background and study aims The etiology of idiopathic acute pancreatitis (IAP) should always be defined. Our aim was to compare the diagnostic value of endoscopic ultrasound (EUS) versus secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) in patients with IAP. Patients and Methods Patients admitted to a single tertiary care University hospital with IAP were invited to participate in the study. Enrolled patients underwent EUS and S-MRCP in a single-blinded comparative study. EUS and S-MRCP were performed no sooner than 4 weeks after discharge. The diagnostic yield of EUS and S-MRCP and demographic variables were included in the analysis. Additional follow-up, results of subsequent serology, radiographic exams, and relevant histological analysis were considered in determination of the final diagnosis. Results A total of 34 patients were enrolled; EUS was normal in six, cholelithiasis was defined in 15, choledocholithiasis in two, pancreas divisum in three, branch-type intraductal papillary mucinous tumor (IPMT) in three, and chronic pancreatitis in five. S-MRCP identified choledocholithiasis in one, divisum in four, branch-type IPMT in three, chronic pancreatitis in two; 24 subjects diagnosed as normal by S-MRCP. Diagnostic correlation between EUS and S-MRCP was slight (kappa = 0.236, 95 % confidence interval: 0.055-0.416). EUS provided a statistically significantly higher diagnostic yield than S-MRCP: 79.4 % (CI95 %: 65 %-94 %) vs 29.4 % (CI95 %: 13 %-46 %) (P = 0.0002). The sensitivity, specificity, and positive and negative predictive values of EUS and S-MRCP were 90 %, 80 %, 96 %, 57 % and 33 %, 100 %, 100 % and 16 %, respectively. Conclusion The diagnostic yield of EUS is higher than S-MRCP in patients with IAP.

Pilot Multi-Omic Analysis of Human Bile from Benign and Malignant Biliary Strictures: A Machine-Learning Approach.

Cholangiocarcinoma (CCA) and pancreatic adenocarcinoma (PDAC) may lead to the development of extrahepatic obstructive cholestasis. However, biliary stenoses can also be caused by benign conditions, and the identification of their etiology still remains a clinical challenge. We performed metabolomic and proteomic analyses of bile from patients with benign (n = 36) and malignant conditions, CCA (n = 36) or PDAC (n = 57), undergoing endoscopic retrograde cholangiopancreatography with the aim of characterizing bile composition in biliopancreatic disease and identifying biomarkers for the differential diagnosis of biliary strictures. Comprehensive analyses of lipids, bile acids and small molecules were carried out using mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (1H-NMR) in all patients. MS analysis of bile proteome was performed in five patients per group. We implemented artificial intelligence tools for the selection of biomarkers and algorithms with predictive capacity. Our machine-learning pipeline included the generation of synthetic data with properties of real data, the selection of potential biomarkers (metabolites or proteins) and their analysis with neural networks (NN). Selected biomarkers were then validated with real data. We identified panels of lipids (n = 10) and proteins (n = 5) that when analyzed with NN algorithms discriminated between patients with and without cancer with an unprecedented accuracy.

Gallbladder perforation after closed thoracoabdominal trauma, diagnosed and treated by ERCP.

Single gallbladder injury after abdominal trauma is a rare finding. Early diagnosis of this disease is often difficult due to the variability of symptoms and unspecific results in the usual radiological tests. The usual management in patients with vesical trauma is surgery. We report a case of a patient with a gallbladder perforation after closed thoracoabdominal trauma diagnosed and treated with ERCP and a conservative management with good clinical evolution.

[Serrated polyps and their association with synchronous advanced colorectal neoplasia]. / Pólipos serrados y su asociación con neoplasia avanzada de colon.

INTRODUCTION: Large serrated polyps (SP), proximal SP, SP with dysplasia and the presence of multiple sessile serrated adenomas/polyps (SSA/P), which we refer to as SP with increased risk of metachronous lesions (SPIRML), have been associated with an increased risk of advanced colon lesions on follow-up. It is unclear, however, whether SPIRML are also associated with an increased risk of synchronous advanced colorectal neoplasia (ACN). AIM: The aim of this study was to estimate the prevalence of SPIRML and to evaluate the association between SPIRML and synchronous ACN. METHODS: A cross-sectional population-based study in all patients (1,538) with histological diagnosis of SP obtained from colonoscopies, sigmoidoscopies and colonic surgery performed in Navarra Health Service hospitals (Spain) in 2011. Demographic parameters and synchronous colonic lesions (adenomas, advanced adenomas [AA] and ACN) were analyzed. RESULTS: One fourth of the sample (384 patients) presented SPIRML. These were older patients, with a slight predominance of women, and with no differences in body mass index (BMI) compared to patients without SPIRML. In the univariate analysis, patients with SPIRML showed an increased risk of adenoma, AA and ACN. In the multivariate analysis, the SPIRML group had a higher risk of synchronous AA and ACN (odds ratio [OR]: 2.38 [1.77-3.21] and OR: 2.29 [1.72-3.05], respectively); in the case of ACN, this risk was statistically significant in both locations (proximal or distal), with OR slightly higher for the proximal location. Different subtypes of SPIRML had a higher risk of AA and synchronous NA. CONCLUSION: SPIRML were common in patients with SP, and their presence was associated with an increased risk of synchronous ACN.

[Prevalence of altered mismatch repair protein nuclear expression detected by immunohistochemistry on adenomas with high-grade dysplasia and features associated with this risk in a population-based study]. / Prevalencia de alteración de expresión nuclear de proteínas reparadoras con inmunohistoquímica sobre adenomas con displasia de alto grado y características asociadas a dicho riesgo en un estudio de base poblacional.

INTRODUCTION: Alteration of mismatch repair system protein expression detected by immunohistochemistry (IHQ) in tumoural tissue is a useful technique for Lynch Syndrome (LS) screening. A recent review proposes LS screening through immunohistochemical study not only in all diagnosed cases of colorectal cancer (CRC) but also in advanced adenomas, especially in young patients. OBJECTIVE: To assess the prevalence of altered IHQ carried out in all adenomas with high-grade dysplasia (HGD) diagnosed in our community in 2011, as well as the variables associated with this alteration. METHODS: We included all the cases of adenomatous polyps with HGD diagnosed in the three public pathology laboratories of Navarre during 2011 and performed a statistical study to assess the association between different patient and lesion characteristics and altered IHQ results. RESULTS: A total of 213 colonic adenomas with HGD were diagnosed, and 26 (12.2%) cases were excluded from the final analysis (2 known LS, 22 without IHQ study and 2 with inconclusive IHQ studies). The final number of adenomas included was 187. Pathologic results were found in 10 cases (5.35%)-6 cases in MLH1 and PMS2, 2 cases in PMS2, 1 case in MSH6 and 1 case in MSH2 and MSH6. The factors showing a statistically significant association with the presence of abnormal proteins were the synchronous presence of CRC, the presence of only one advanced adenoma, proximal location of HGD and age <50 years. CONCLUSIONS: The percentage of pathologic nuclear expression found in IHQ is high. Consequently, screening of all diagnosed HGD could be indicated, especially in young patients, with a single AA and proximal HGD.

[Predictive value of pre-treatment hypoalbuminemia in prognosis of resected colorectal cancer]. / Valor predictivo de la hipoalbuminemia pre-tratamiento sobre el pronóstico del cáncer colorrectal resecado.

INTRODUCTION: Albuminemia is part of the antitumoral systemic inflammatory response. We therefore analyzed its possible value in establishing the preoperative prognosis of colorectal carcinoma (CRC). PATIENTS AND METHODS: We conducted a retrospective, observational study of a series of consecutive patients who underwent CRC resection. Univariate and multivariate analyses of survival curves were performed in patients with and without pre-treatment hypoalbuminemia (<3.5g/dl), both in the overall group of patients and in the subgroup of those with pTNM stage ii tumors. In addition, we compared the 5-year tumor-related mortality in patients with and without hypoalbuminemia. RESULTS: A total of 207 patients were reviewed (median follow-up: 81 months). In the overall multivariate analysis, survival curves were better in patients with normal albumin levels than in those with hypoalbuminemia (HR=2.82; CI 95%=[1.54-5.19]; P=.001). This better prognostic value of normal albumin levels was also significant in pTNM stage ii tumors: (HR=3.76; CI 95%=[1.40-10.08]; P=.009). The 5-year mortality index was lower in patients with normal albumin levels: overall series=18.8% vs 42.9% (OR=3.24; CI 95%=[1.48-7.12]; p=0.001); pTNM stage ii=13.3% vs 44.4% (OR=5.2; CI 95%=[1.36-20.34]; P=0.004). CONCLUSIONS: Pre-treatment hypoalbuminemia (<3.5g/dl) was independently related to shorter survival after tumor resection, both in the overall series of patients and in pTNM stage ii CRC. If these results are confirmed, hypoalbuminemia would be a simple and significant marker of poor prognosis, available at the initial diagnosis.

[Ectopic retroperitoneal thyroid gland]. / Ectopia tiroidea retroperitoneal.

The presence of subdiaphragmatic thyroid tissue is a very rare finding. We reviewed the literature and found only 15 published cases. The most appropriate management of this entity has not been established, but surgical removal is common to exclude malignancy. We present the case of a 76-year-old woman with an ectopic mesenteric thyroid gland forming a retroperitoneal mass that was surgically removed. Outcome was favorable.

Gastric perforation related to a transgastric biliary drainage procedure with endoscopic Rendez-Vous technique.

Endoscopic ultrasound-guided bilio-pancreatic drainage (EBPD) has become an endoscopic alternative to percutaneous biliary drainage for patients with unsuccessful transpapillary approach. EBPD has a significant complication rate and expertise in advanced therapeutical endoscopy and endosonography are required. We present a 43 year-old male with pancreatic head adenocarcinoma, who after underwent a transgastric endoscopic rendez-vous technique, a gastric wall perforation at the fistula location was detected. We endoscopically sealed the gastric perforation and the patient had an uneventful recovery.

Z-line examination by the PillCam SB: prospective comparison of three ingestion protocols.

AIM: To evaluate the Z-line visualization by the PillCam SB2 using three different ingestion protocols. METHODS: Ninety consecutive patients undergoing small bowel capsule endoscopy (SBCE) between January and May 2008 were included in the study. They swallowed the capsule in the standing (Group A = 30), supine (Group B = 30) and right supine positions (Group C = 30). Baseline patient characteristics, difficulties in capsule ingestion, esophageal transit times (ETT) and Z-line visualization were noted. RESULTS: No significant differences were found between the groups with regard to baseline patient characteristics, ingestion difficulties and complete SB examinations (P > 0.05). At least 1 frame of the Z-line was detected in 15.8%, 46.7% and 90% of patients in groups A, B and C, respectively (P < 0.001). The average number of Z-line images was 0.21 +/- 0.53, 3.23 +/- 6.59 and 5.53 +/- 7.55 and the mean % of the Z-line detected was 71.3, 25.1 and 8.3, in groups A, B and C, respectively (both P < 0.001). ETT times were longer in the supine group followed by the right supine and the standing groups (median of 237 s vs 64 s and 39 s, respectively; P < 0.001). CONCLUSION: Z-line visualization in patients undergoing SBCE can be accurately achieved in most cases when the capsule is swallowed in the right supine position.