Anton H. Naber

Low-Grade Dysplasia in Barrett's Esophagus: Overdiagnosed and Underestimated

OBJECTIVES:Published data on the natural history of low-grade dysplasia (LGD) in Barretts esophagus (BE) are inconsistent and difficult to interpret. We investigated the natural history of LGD in a large community-based cohort of BE patients after reviewing the original histological diagnosis by an expert panel of pathologists.METHODS:Histopathology reports of all patients diagnosed with LGD between 2000 and 2006 in six non-university hospitals were reviewed by two expert pathologists. This panel diagnosis was subsequently compared with the histological outcome during prospective endoscopic follow-up.RESULTS:A diagnosis of LGD was made in 147 patients. After pathology review, 85% of the patients were downstaged to non-dysplastic BE (NDBE) or to indefinite for dysplasia. In only 15% of the patients was the initial diagnosis LGD. Endoscopic follow-up was carried out in 83.6% of patients, with a mean follow-up of 51.1 months. For patients with a consensus diagnosis of LGD, the cumulative risk of progressing to high-grade dysplasia or carcinoma (HGD or Ca) was 85.0% in 109.1 months compared with 4.6% in 107.4 months for patients downstaged to NDBE (P<0.0001). The incidence rate of HGD or Ca was 13.4% per patient per year for patients in whom the diagnosis of LGD was confirmed. For patients downstaged to NDBE, the corresponding incidence rate was 0.49%.CONCLUSIONS:LGD in BE is an overdiagnosed and yet underestimated entity in general practice. Patients diagnosed with LGD should undergo an expert pathology review to purify this group. In case the diagnosis of LGD is confirmed, patients should undergo strict endoscopic follow-up or should be considered for endoscopic ablation therapy.

Population-based epidemiology, malignancy risk, and outcome of primary sclerosing cholangitis.

Extensive population‐based studies are much needed to accurately establish epidemiology and disease course in patients with primary sclerosing cholangitis (PSC). We aimed to obtain population‐based prevalence and incidence figures, insight in disease course with regard to survival, liver transplantation (LT), and occurrence of malignancies, as well as risk factors thereof. Four independent hospital databases were searched in 44 hospitals in a large geographically defined area of the Netherlands, comprising 50% of the population. In addition, all PSC patients in the three Dutch liver transplant centers and all inflammatory bowel disease (IBD) patients in the adherence area of a large district hospital were identified. All medical records were reviewed on‐site, verifying diagnosis. Five hundred and ninety PSC patients were identified, resulting in an incidence of 0.5 and a point prevalence of 6.0 per 100,000. Median follow up was 92 months. Estimated median survival from diagnosis until LT or PSC‐related death in the entire cohort was 21.3 years, as opposed to 13.2 years in the combined transplant centers cohort (n = 422; P < 0.0001). Colorectal carcinoma (CRC) risk was 10‐fold increased, as compared to ulcerative colitis controls, and developed at a much younger age (39 years; range, 26‐64), compared to IBD controls (59 years; range, 34‐73; P = 0.019). Colonoscopic surveillance was associated with significantly better outcome. Conclusion: This study exemplifies that, for relatively rare diseases, it is paramount to collect observational data from large, population‐based cohorts, because incidence and prevalence rates of PSC are markedly lower and survival much longer than previously reported. The selection of a bias‐free, population‐based cohort showed a significantly longer survival, compared to the tertiary referral cohort. CRC can develop at an early age, warranting surveillance from time of PSC diagnosis. (Hepatology 2013; 58:2045–2055)

Endoscopic trimodal imaging versus standard video endoscopy for detection of early Barrett's neoplasia: a multicenter, randomized, crossover study in general practice

BACKGROUND Endoscopic trimodal imaging (ETMI) may improve detection of early neoplasia in Barretts esophagus (BE). Studies with ETMI so far have been performed in tertiary referral settings only. OBJECTIVE To compare ETMI with standard video endoscopy (SVE) for the detection of neoplasia in BE patients with an intermediate-risk profile. DESIGN Multicenter, randomized, crossover study. SETTING Community practice. PATIENTS AND METHODS BE patients with confirmed low-grade intraepithelial neoplasia (LGIN) underwent both ETMI and SVE in random order (interval 6-16 weeks). During ETMI, BE was inspected with high-resolution endoscopy followed by autofluorescence imaging (AFI). All visible lesions were then inspected with narrow-band imaging. During ETMI and SVE, visible lesions were sampled followed by 4-quadrant random biopsies every 2 cm. MAIN OUTCOME MEASUREMENTS Overall histological yield of ETMI and SVE and targeted histological yield of ETMI and SVE. RESULTS A total of 99 patients (79 men, 63±10 years) underwent both procedures. ETMI had a significantly higher targeted histological yield because of additional detection of 22 lesions with LGIN/high-grade intraepithelial neoplasia (HGIN)/carcinoma (Ca) by AFI. There was no significant difference in the overall histological yield (targeted+random) between ETMI and SVE. HGIN/Ca was diagnosed only by random biopsies in 6 of 24 patients and 7 of 24 patients, with ETMI and SVE, respectively. LIMITATIONS Inspection, with high-resolution endoscopy and AFI, was performed sequentially. CONCLUSION ETMI performed in a community-based setting did not improve the overall detection of dysplasia compared with SVE. The diagnosis of dysplasia is still being made in a significant number of patients by random biopsies. Patients with a confirmed diagnosis of LGIN have a significant risk of HGIN/Ca. ( CLINICAL TRIAL REGISTRATION NUMBER ISRCTN91816824; NTR867.).

Endoscopic trimodal imaging detects colonic neoplasia as well as standard video endoscopy.

BACKGROUND & AIMS Endoscopic trimodal imaging (ETMI) is a novel endoscopic technique that combines high-resolution endoscopy (HRE), autofluorescence imaging (AFI), and narrow-band imaging (NBI) that has only been studied in academic settings. We performed a randomized, controlled trial in a nonacademic setting to compare ETMI with standard video endoscopy (SVE) in the detection and differentiation of colorectal lesions. METHODS The study included 234 patients scheduled to receive colonoscopy who were randomly assigned to undergo a colonoscopy in tandem with either ETMI or SVE. In the ETMI group (n=118), first examination was performed using HRE, followed by AFI. In the other group, both examinations were performed using SVE (n=116). In the ETMI group, detected lesions were differentiated using AFI and NBI. RESULTS In the ETMI group, 87 adenomas were detected in the first examination (with HRE), and then 34 adenomas were detected during second inspection (with AFI). In the SVE group, 79 adenomas were detected during the first inspection, and then 33 adenomas were detected during the second inspection. Adenoma detection rates did not differ significantly between the 2 groups (ETMI: 1.03 vs SVE: 0.97, P=.360). The adenoma miss-rate was 29% for HRE and 28% for SVE. The sensitivity, specificity, and accuracy of NBI in differentiating adenomas from nonadenomatous lesions were 87%, 63%, and 75%, respectively; corresponding values for AFI were 90%, 37%, and 62%, respectively. CONCLUSIONS In a nonacademic setting, ETMI did not improve the detection rate for adenomas compared with SVE. NBI and AFI each differentiated colonic lesions with high levels of sensitivity but low levels of specificity.

Medium-chain triglyceride containing lipid emulsions increase human neutrophil beta2 integrin expression, adhesion and degranulation

BACKGROUND To test the hypothesis that lipid emulsions with different triglyceride structures have distinct immunomodulatory properties, we analyzed human neutrophil adhesion and degranulation after lipid incubation. METHODS Neutrophils, isolated from the blood of 10 healthy volunteers, were incubated in medium or physiologic (2.5 mmol/L) emulsions containing long-chain (LCT), medium-chain (MCT), mixed LCT/MCT, or structured (SL) triglycerides. Expression of adhesion molecules and degranulation markers was evaluated by flow cytometry. Also, functional adhesion was investigated by means of a flow cytometric assay using fluorescent beads coated with the integrin ligand intercellular adhesion molecule (ICAM)-1. RESULTS Although LCT and SL had no effect, LCT/MCT significantly increased expression of the beta2 integrins lymphocyte-function-associated antigen 1 (+18%), macrophage antigen 1 (+387%), p150,95 (+82%), and (alphaDbeta2 (+230%). Degranulation marker expression for azurophilic (CD63, +210%) and specific granules (CD66b, +370%) also significantly increased, whereas L-selectin (CD62L, -70%) decreased. The effects of LCT/MCT were mimicked by the MCT emulsion. ICAM-1 adhesion (% beads bound) was increased by LCT/MCT (34% +/- 4%), whereas LCT (19% +/-3%) and SL (20% +/- 2%) had no effect compared with medium (17% +/- 3%). CONCLUSIONS LCT/MCT and MCT, contrary to LCT and SL emulsions, increased neutrophil beta2 integrin expression, adhesion, and degranulation. Apart from other emulsion constituents, triglyceride chain length might therefore be a key feature in the interaction of lipid emulsions and the phagocyte immune system.

Phagocytosis and killing of Candida albicans by human neutrophils after exposure to structurally different lipid emulsions.

BACKGROUND To test the hypothesis that structurally different lipid emulsions have distinct immune-modulating properties, we analyzed the elimination of Candida albicans by neutrophils after exposure to various emulsions. METHODS Neutrophils from 8 volunteers were incubated in physiologic 5 mmol/L emulsions containing long-chain- (LCT), medium-chain- (MCT), mixed LCT/MCT-, alpha-tocopherol-enriched LCT/MCT (LCT/MCT-E), or structured lipids (SL). After washing, the neutrophils were incubated with C. albicans. Phagocytosis was measured as the number of yeast-associated neutrophils relative to the total neutrophil count. Killing was expressed as the percentage of Candida survival relative to the initial yeast cell count. RESULTS No significant differences in yeast-neutrophil association could be demonstrated after neutrophil incubation in various lipid emulsions or medium, after correction for non-specific adhesion. However, although Candida survival after 1 hour incubation with non-lipid-exposed neutrophils amounted to 53% +/- 11% and was not influenced by LCT (60% +/- 11%), LCT/MCT (78% +/- 7%), LCT/MCT-E (72% +/- 12%), and SL (67% +/- 6%), pure MCT (70% +/- 13%) significantly impaired the killing capacity of neutrophils. CONCLUSIONS The decreased killing capacity of neutrophils after exposure to medium-chain fatty acid-containing emulsions and the absence of this effect with LCT suggest that lipid emulsions influence the elimination of C. albicans depending on the triglyceride chain length.

With Medium-Chain Triglycerides, Higher and Faster Oxygen Radical Production by Stimulated Polymorphonuclear Leukocytes Occurs

BACKGROUND Parenteral lipid emulsions are suspected of suppressing the immune function. However, study results are contradictory and mainly concern the conventional long-chain triglyceride emulsions. METHODS Polymorphonuclear leukocytes were preincubated with parenteral lipid emulsions. The influence of the lipid emulsions on the production of oxygen radicals by these stimulated leukocytes was studied by measuring chemiluminescence. Three different parenteral lipid emulsions were tested: long-chain triglycerides, a physical mixture of medium- and long-chain triglycerides, and structured triglycerides. Structured triglycerides consist of triglycerides where the medium- and long-chain fatty acids are attached to the same glycerol molecule. RESULTS Stimulated polymorphonuclear leukocytes preincubated with the physical mixture of medium- and long-chain triglycerides showed higher levels of oxygen radicals (p < .005) and faster production of oxygen radicals (p < .005) compared with polymorphonuclear leukocytes preincubated with long-chain triglycerides or structured triglycerides. Additional studies indicated that differences in results of various lipid emulsions were not caused by differences in emulsifier. The overall production of oxygen radicals was significantly lower after preincubation with the three lipid emulsions compared with controls without lipid emulsion. CONCLUSIONS A physical mixture of medium- and long-chain triglycerides induced faster production of oxygen radicals, resulting in higher levels of oxygen radicals, compared with long-chain triglycerides or structured triglycerides. This can be detrimental in cases where oxygen radicals play either a pathogenic role or a beneficial one, such as when rapid phagocytosis and killing of bacteria is needed. The observed lower production of oxygen radicals by polymorphonuclear leukocytes in the presence of parenteral lipid emulsions may result in immunosuppression by these lipids.

Human Neutrophil Membrane Fluidity After Exposure to Structurally Different Lipid Emulsions

BACKGROUND We have previously reported that medium-chain triglyceride (MCT)-containing lipid emulsions, contrary to long-chain triglyceride (LCT) emulsions, activate human neutrophils. This activation might result from functional alterations in cellular membranes induced by MCT. Membrane fluidity is such a feature with known clinical implications and can be assessed by fluorescence polarization measurements. This study was performed to investigate whether exposure to various emulsions distinctively influences neutrophil membrane fluidity. METHODS Neutrophils from 8 volunteers were incubated in medium or physiologic 2.5 mmol/L emulsions containing LCT, mixed LCT/MCT, or structured lipids (SL). Subsequently, the cells were washed and anisotropy, ie, the reciprocal of fluidity, was measured using the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene (DPH) and trimethyl-ammonium (TMA)-DPH. RESULTS Compared with nonlipid-exposed neutrophils, LCT/MCT and, to a lesser degree, SL decreased fluorescence anisotropy and thus increased membrane fluidity, which was measured by DPH anisotropy, whereas LCT had no effect. Similar results were obtained with the more polar probe TMA-DPH. CONCLUSIONS These data suggest that the neutrophil-activating effect of MCT-containing emulsions may, at least in part, be mediated by an effect on cellular membrane fluidity.

Risk factors for primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a progressive cholestatic liver disease of unknown cause, but strongly associated with inflammatory bowel disease (IBD). Potential risk factors triggering PSC have never been studied on a population level. The aim of this study was to evaluate smoking, appendectomy, family history and geographical distribution in a population‐based cohort of PSC patients, as compared to IBD control patients and healthy controls (HC).

Su1181 A Diagnostic DNA FISH Biomarker Assay Identifies HGD or EAC in Barrett Esophagus

examine the effect of acid on Wnt/β-catenin signaling activation and on regulating the expression of Dickkopf1 (DKK1), an inhibitor of the Wnt. Methods: Normal esophageal squamous cells lines (EPC1-hTERT, EPC2-hTERT), a non-dysplastic Barretts esophageal cell line (CP-A) and an esophageal adenocarcinoma cell line (OE33) were exposed to acidic media (pH 4.0) in a pulsive manner. Human esophageal mucosal biopsies in triplicate from healthy (n=1), NERD (n=1), GERD (n=1) and Barretts (n=1) patients were obtained and cultured in acidic (pH 4.0) or non acidic media. Localization and levels of β-catenin were determined by Immunofluorescence staining and Western blot. Wnt-activity was assessed by Luciferase assay following transfection with β-catenin-LEF/TCF-sensitive (TOP) or βcatenin-LEF/TCF insensitive (FOP) reporter vector. Immunofluorescence was used for βcatenin and E-Cadherin co-localization. DKK1 and β-catenin gene expression was resolved by qRT-PCR. DKK1 secretion in cells culture media and organ culture media was quantified by ELISA assay.Results: Acid destabilized E-cadherin/β-catenin complex in cell-cell junctions and resulted in β-catenin translocation to nucleus. Wnt-activity correlated with nuclear translocation of β-catenin. Cytosolic shuttling of β-catenin occurred in a rapid and transient manner after acid withdrawal. Chronic pulsed acid exposure increased DKK1 expression in normal squamous cells but not in metaplastic columnar cells. DKK1 overexpression correlated with a significant degradation of β-catenin. Mucosal biopsies from patients with NERD/ GERD secreted significantly higher levels of Dkk1 than healthy and metaplastic mucosa biopsies. Conclusions: These findings suggest that acid reflux induces the activation of Wnt-signaling pathway and that the overexpression of DKK1 is the long term response in the normal squamous esophageal tissue but not in the Barretts esophagus. These findings also suggest a homeostatic role for DKK1 in GERD and its dysfunction to be a potential mechanism for progression to Barretts metaplasia.