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Gut

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Gut

Portal hypertension (PHT) is a heterogeneous clinical entity which develops in patients with cirrhosis. It is responsible for many of the complications that occur in cirrhosis, including gastroesophageal varices, hepatorenal syndrome, ascites, hepatic encephalopathy and hypersplenism.1 There are three principal factors responsible for the development of PHT, namely (1) purely mechanical obstruction resulting from hepatic fibrosis and regenerative nodules; (2) contraction of sinusoidal and perisinusoidal contractile cells due to an imbalance between intrahepatic vasoconstrictory and vasodilatory mediators and (3) splanchnic vasodilation and increased portal blood flow.1 Factors leading to the development of PHT include hypoxia, oxidative stress, inflammation and shear stress as potential mediators for the angiogenic response. Vascular Endothelial Growth factor (VEGF) is a key mediator in regulating the angiogenic switch in many pathological conditions, and is also probably a major player in the neoangiogenic process during the development of a hyperdynamic splanchnic circulation,...


Non-alcoholic fatty liver disease (NAFLD), the hepatic counterpart of metabolic syndrome, has gained increasing recognition worldwide as a component of the obesity and type 2 diabetes pandemic. The spectrum of NAFLD ranges from simple fatty liver with benign prognosis, to non-alcoholic steatohepatitis (NASH), which may progress to liver fibrosis and cirrhosis, thereby increasing morbidity and mortality. According to the traditional view, hepatic fat accumulation represents the prerequisite for hepatocyte injury to develop, whereas cytokines, adipokines, bacterial endotoxin, mitochondrial dysfunction and/or endoplasmic reticulum stress are described as aggravating factors involved in NASH progression. It is believed that approximately 1%–5% of the Western population exhibit NASH. However, no therapeutic approaches are currently effective in slowing or reversing NASH, and the most promising treatments remain weight loss and exercise. Generating rodent models for preclinical investigations on NASH has been quite challenging over the past years for several laboratories.1–3


Treatment cessation is one of the few challenges left to clinicians to deal with after the marketing and widespread use of third generation oral analogues (nucleos(t)ide analogue (NUC)), entecavir (ETV) and tenofovir (TDF) for the treatment of HBeAg negative chronic hepatitis B (CHB). Treatment efficacy is in fact unquestioned as more than 95% of patients, including NUC experienced and resistant ones, achieve complete suppression of viral replication and improvement of hepatic inflammation and fibrosis within the first 5 years of treatment.1–3 As a consequence, in a majority of patients, progression to cirrhosis is prevented, and clinical decompensation and portal hypertension either improved or prevented, with hepatocellular carcinoma (HCC) remaining the only complication in HBeAg negative patients long-term treated for with ETV or TDF.4 Indeed, the yearly attack rates of HCC range between 0.5% and 1% among non-cirrhotics and 2.5% and 4% among...


Circulating tumour cells (CTCs) are being used for the prediction of disease progression and drug sensitivity for various types of cancers. Current CTC isolation depends on epithelial cell surface proteins which can therefore miss CTCs that are non-epithelial.

Shigeyasu et al1 describe technology to capture, sort and characterise epithelial and non-epithelial CTCs using a green fluorescent protein (GFP)-expressing attenuated adenovirus, in which the telomerase promoter regulates viral replication (OBP-401). OBP-401 selectively labels cancer cells, including CTCs, that express telomerase, which should include the vast majority of any type of cancer cell, since cancer cells in general express telomerase.2 Shigeyasu et al isolated CTCs from patients with colon cancer using their adenoviral GFP labelling technology but have not yet tested the technology on normal patients to demonstrate specificity. This study is published in Gut.1

Shigeyasu et al1 capture, image and characterise epithelial...


Introduction

Acute renal failure (ARF) is a common complication in patients with decompensated cirrhosis. The traditional diagnostic criteria of renal failure in these patients were proposed in 19961 and have been refined in subsequent years.2 According to these criteria, ARF is defined as an increase in serum creatinine (sCr) of ≥50% from baseline to a final value >1.5 mg/dL (133 µmol/L). However, the threshold value of 1.5 mg/dL (133 µmol/L) sCr to define renal failure in patients with decompensated cirrhosis has been challenged.3 4 In addition, the timeframe to distinguish acute from chronic renal failure has not been clearly identified, the only exception being type 1 hepatorenal syndrome (HRS). Meanwhile, new definitions for ARF, now termed acute kidney injury (AKI), have been proposed and validated in patients without cirrhosis.5–7 Recently these new criteria were also proposed and applied...


Background

Eosinophilic oesophagitis (EoE) is presumed to be an isolated oesophageal disease; yet other allergic diseases associated with eosinophilic infiltration of target tissues, such as asthma and eczema, show perturbed functions of other sites that may be involved in the diathesis of allergy modulation.

Aim

To analyse small intestinal permeability in patients with active EoE and in a separate group of patients in remission.

Methods

Small bowel permeability was determined using a dual sugar method by calculating lactulose:mannitol (L:M) ratio in 17 patients who met consensus criteria for active EoE (>15 eos/HPF) and 8 patients in remission (<5 eos/HPF). Data from 28 healthy controls was used for comparison.

Results

Patients with active EoE had significantly higher L:M ratios when compared to controls (0.045 vs. 0.033, p<0.001) and to EoE in remission (0.041 vs. 0.027, p<.001). There was no significant difference in L:M between the group with EoEin remission and healthy controls. The current data show that L:M ratio of 0.033 also provides a reasonable cut-off that defined the active EoE group compared to patients in remission. The main component explaining the change in L:M ratio was increased absorption (and excretion) of lactulose ((1601±106 ug) when compared to the EoE remission (969±91 ug) and control (1043±92 ug, p<.001) groups.

Conclusions

Small bowel permeability is overall increased in patients with active EoE, and is normal in patients with EoE in remission when compared to healthy controls. The role of the small bowel in active EoE deserves further investigation.


Objective

Progastrin is the incompletely cleaved precursor of gastrin that is secreted by G-cells in the gastric antrum. Both gastrin and progastrin bind to the CCK2 receptor (Cckbr or CCK2R) expressed on a subset of gastric epithelial cells. Little is known about how gastrin peptides and CCK2R regulate gastric stem cells and carcinogenesis. Interconversion among progenitors in the intestine is documented, but the mechanisms by which this occurs are poorly defined.

Design

We generated CCK2R-CreERT mice and performed inducible lineage tracing experiments. CCK2R+ antral cells and Lgr5+ antral stem cells were cultured in a three-dimensional in vitro system. We crossed progastrin-overexpressing mice with Lgr5-GFP-CreERT mice and examined the role of progastrin and CCK2R in Lgr5+ stem cells during MNU-induced carcinogenesis.

Results

Through lineage tracing experiments, we found that CCK2R defines antral stem cells at position +4, which overlapped with an Lgr5neg or low cell population but was distinct from typical antral Lgr5high stem cells. Treatment with progastrin interconverts Lgr5neg or low CCK2R+ cells into Lgr5high cells, increases CCK2R+ cell numbers and promotes gland fission and carcinogenesis in response to the chemical carcinogen MNU. Pharmacological inhibition or genetic ablation of CCK2R attenuated progastrin-dependent stem cell expansion and carcinogenesis.

Conclusions

CCK2R labels +4 antral stem cells that can be activated and expanded by progastrin, thus identifying one hormonal trigger for gastric stem cell interconversion and a potential target for gastric cancer chemoprevention and therapy.


Objective

To study the detailed nature of genomic microevolution during mixed infection with multiple Helicobacter pylori strains in an individual.

Design

We sampled 18 isolates from a single biopsy from a patient with chronic gastritis and nephritis. Whole-genome sequencing was applied to these isolates, and statistical genetic tools were used to investigate their evolutionary history.

Results

The genomes fall into two clades, reflecting colonisation of the stomach by two distinct strains, and these lineages have accumulated diversity during an estimated 2.8 and 4.2 years of evolution. We detected about 150 clear recombination events between the two clades. Recombination between the lineages is a continuous ongoing process and was detected on both clades, but the effect of recombination in one clade was nearly an order of magnitude higher than in the other. Imputed ancestral sequences also showed evidence of recombination between the two strains prior to their diversification, and we estimate that they have both been infecting the same host for at least 12 years. Recombination tracts between the lineages were, on average, 895 bp in length, and showed evidence for the interspersion of recipient sequences that has been observed in in vitro experiments. The complex evolutionary history of a phage-related protein provided evidence for frequent reinfection of both clades by a single phage lineage during the past 4 years.

Conclusions

Whole genome sequencing can be used to make detailed conclusions about the mechanisms of genetic change of H. pylori based on sampling bacteria from a single gastric biopsy.


Objective

Colonic fermentation in patients with UC in remission was compared with that in matched healthy subjects on habitual diets and when dietary fibre was increased.

Design

Fibre intake, faecal output of fibre (measured as non-starch polysaccharide (NSP)), starch, microbiota and fermentation products, and whole gut transit time (WGTT) were assessed in association with habitual diet and when dietary intake of wheat bran (WB)-associated fibre and high amylose-associated resistant starch (RS) was increased in an 8-week, randomised, single-blind, cross-over study.

Results

Despite a tendency to lower habitual fibre intake in UC patients, faecal NSP and starch concentrations were threefold higher than in controls, whereas concentrations of phenols and short-chain fatty acids, pH and WGTT were similar. Increasing RS/WB intake was well tolerated. In controls (n=10), it more than doubled faecal NSP and starch excretion (p=0.002 for both), had no effect on NSP usage and reduced WGTT (p=0.024). In UC patients (n=19), high intake of RS/WB tended to normalise gut transit, but did not increase the proportion of NSP fermented. Increasing intake of RS/WB had little effect on faecal fermentation patterns or the structure of the microbiota. However, faeces from the UC cohort had lower proportions of Akkermansia muciniphila and increased diversity within Clostridium cluster XIVa compared to controls.

Conclusions

Gut fermentation of NSP and starch is diminished in patients with UC. This cannot be explained by abnormal gut transit and was not corrected by increasing RS/WB intake, and may be due to abnormal functioning of the gut microbiota.

Trial registration number

Australian New Zealand Clinical Trials Registry: ACTRN12614000271606.


Objective

Over 100 ulcerative colitis (UC) loci have been identified by genome-wide association studies (GWASs) primarily in Caucasians (CEUs). Many of them have weak effects on disease susceptibility, and the bulk of the heritability cannot be ascribed to these loci. Very little is known about the genetic background of UC in non-CEU groups. Here we report the first GWAS on UC in a genetically distinct north Indian (NI) population.

Design

A genome-wide scan was performed on 700 cases and 761 controls. 18 single-nucleotide polymorphisms (SNPs) (p<5x10–5) were genotyped in an independent cohort of 733 cases and 1148 controls. A linear mixed model was used for case–control association tests.

Results

Seven novel human leucocyte antigen (HLA)-independent SNPs from chromosome 6, located in 3.8-1, BAT2, MSH5, HSPA1L, SLC44A4, CFB and NOTCH4, exceeded p<5x10–8 in the combined analysis. To assess the independent biological contribution of such genes from the extended HLA region, we determined the percentage alternative pathway activity of complement factor B (CFB), the top novel hit. The activity was significantly different (p=0.01) between the different genotypes at rs12614 in UC cases. Transethnic comparisons revealed a shared contribution of a fraction of UC risk genes between NI and CEU populations, in addition to genetic heterogeneity.

Conclusions

This study shows varying contribution of the HLA region to UC in different populations. Different environmental exposures and the characteristic genetic structure of the HLA locus across ethnic groups collectively make it amenable to the discovery of causative alleles by transethnic resequencing. This may lead to an improved understanding of the molecular mechanisms underlying UC.


Objective

Data to support treatment algorithms in ambulatory paediatric UC are scarce. We aimed to explore the 1 year outcome in an inception cohort of paediatric UC patients and to identify early predictors of good outcome that might serve as short term treatment targets.

Design

A chart review of 115 children with new onset UC was performed (age 11±4.1 years; 58 (50%) males; 86 (75%) extensive colitis; 70 (61%) moderate–severe disease; 63 (55%) received steroids at baseline). We assessed the Paediatric Ulcerative Colitis Activity Index (PUCAI) and laboratory variables at the time of diagnosis and at 3 months, and endoscopy at diagnosis.

Results

The 3 month PUCAI was the strongest predictor of 1 year sustained steroid free remission (SSFR) (area under the receiver operating characteristic curve (AUROC)=0.7 (95% CI 0.6 to 0.8) and colectomy by 2 years (AUROC=0.75 (0.6 to 0.89)). SSFR was achieved in 9/54 (17%) children who had active disease (PUCAI ≥10) at 3 months (negative predictive value (NPV)=83%) and by 4/46 (8.6%) of those with a PUCAI score >10; (NPV=91%, positive predictive value=52%; p<0.001), implying that PUCAI >10 at 3 months has a probability of 9% for achieving SSFR versus 48% with a PUCAI value of ≤10. None of the variables at baseline was predictive of SSFR or colectomy (endoscopic severity, disease extent, age, PUCAI or C reactive protein/erythrocyte sedimentation rate/albumin/haemoglobin; all AUROC<0.6, p>0.05) but baseline PUCAI predicted subsequent acute severe colitis and the need for salvage medical therapy.

Conclusions

Completeness of the early response appears more important than baseline UC severity for predicting outcome in children, and supports using PUCAI<10 as a feasible treatment goal. Our data suggest that treatment escalation should be considered with a PUCAI value of ≥10 at 3 months.


Objective

Inflammation plays crucial roles in the pathogenesis of several chronic inflammatory disorders, including Crohn's disease (CD) and UC, the two major forms of IBD. The urokinase plasminogen activator receptor (uPAR) exerts pleiotropic functions over the course of both physiological and pathological processes. uPAR not only has a key role in fibrinolysis but also modulates the development of protective immunity. Additionally, uPAR supports extracellular matrix degradation and regulates cell migration, adhesion and proliferation, thus influencing the development of inflammatory and immune responses. This study aimed to evaluate the role of uPAR in the pathogenesis of IBD.

Design

The functional role of uPAR was assessed in established experimental models of colitis. uPAR deficiency effects on cytokine release, polarisation and bacterial phagocytosis were analysed in colonic macrophages. uPAR expression was analysed in surgical specimens collected from normal subjects and patients with IBD.

Results

In mice, uPAR expression is positively regulated as colitis progresses. uPAR-KO mice displayed severe inflammation compared with wild-type littermates, as indicated by clinical assessment, endoscopy and colon histology. The absence of uPAR led to an increased production of inflammatory cytokines by macrophages that showed an M1 polarisation and impaired phagocytosis. In human IBD, CD68+ macrophages derived from the inflamed mucosa expressed low levels of uPAR.

Conclusions

These findings point to uPAR as an essential component of intestinal macrophage functions and unravel a new potential target to control mucosal inflammation in IBD.


Objectives

Intestinal epithelial cells (IEC) express toll-like receptors (TLR) that facilitate microbial recognition. Stimulation of TLR ligands induces a transient increase in epithelial cell shedding, a mechanism that serves the antibacterial and antiviral host defence of the epithelium and promotes elimination of intracellular pathogens. Although activation of the extrinsic apoptosis pathway has been described during inflammatory shedding, its functional involvement is currently unclear.

Design

We investigated the functional involvement of caspase-8 signalling in microbial-induced intestinal cell shedding by injecting Lipopolysaccharide (LPS) to mimic bacterial pathogens and poly(I:C) as a probe for RNA viruses in vivo.

Results

TLR stimulation of IEC was associated with a rapid activation of caspase-8 and increased epithelial cell shedding. In mice with an epithelial cell-specific deletion of caspase-8 TLR stimulation caused Rip3-dependent epithelial necroptosis instead of apoptosis. Mortality and tissue damage were more severe in mice in which IECs died by necroptosis than apoptosis. Inhibition of receptor-interacting protein (Rip) kinases rescued the epithelium from TLR-induced gut damage. TLR3-induced necroptosis was directly mediated via TRIF-dependent pathways, independent of Tnf-α and type III interferons, whereas TLR4-induced tissue damage was critically dependent on Tnf-α.

Conclusions

Together, our data demonstrate an essential role for caspase-8 in maintaining the gut barrier in response to mucosal pathogens by permitting inflammatory shedding and preventing necroptosis of infected cells. These data suggest that therapeutic strategies targeting the cell death machinery represent a promising new option for the treatment of inflammatory and infective enteropathies.


A 47-year-old man presented with mild epigastric pain, dyspepsia and 4 kg weight loss for the last 2 months. There was no history of fever, GI bleeding, cough or pertinent past illnesses or surgery. Physical examination was unremarkable. Routine laboratory tests were within the normal range except for mild anaemia (haemoglobin concentration 11.4 g/dL) and increased erythrocyte sedimentation rate (54 mm/h). ECG and chest X-ray were normal, and serology of HIV, HBV and HCV were negative. Upper endoscopy showed several multilobulated subepithelial lesions (SEL) in the gastric body, cardia and antrum with normal overlying mucosa (figure 1A). Serum chromogranin A and urinary 5-hydroxyindoleacetic acid levels were within normal range. Endoscopic ultrasonography (EUS, figure 1B) and EUS-guided fine needle aspiration (EUS-FNA) were performed. Cytological samples are shown in figure 2.

Question

What is the diagnosis?

See page 683 for answer

See page 610 for question


Objectives

Autonomic nervous system dysfunction has been implicated in visceral hypersensitivity. However, the specific contribution of the parasympathetic nervous system (PNS) is unclear. We aimed to determine whether physiological and pharmacological manipulation of parasympathetic tone influences the development of hypersensitivity in a validated model of acid-induced oesophageal pain.

Design

Prior to, and following, a 30-min distal oesophageal infusion of 0.15 M hydrochloric acid, pain thresholds to electrical stimulation were determined in the proximal non-acid exposed oesophagus in healthy subjects. Validated sympathetic (skin conductance response) and parasympathetic (cardiac vagal tone) parameters were measured at baseline and continuously thereafter. In study 1, 55 subjects were randomised in a pragmatic blinded crossover design to receive deep breathing or un-paced breathing during acid infusion. In study 2, 32 subjects were randomised in a blinded, crossover design to receive intravenous atropine or placebo (saline) with deep breathing during acid infusion.

Results

Study 1: Deep breathing increased cardiac vagal tone (2.1±2.3 vs –0.3±2.3, p=0.0006) with concomitant withdrawal of skin conductance response (–0.6±4.9 vs 3±4.8, p=0.03) in comparison with un-paced breathing. Deep breathing prevented the development of acid-induced oesophageal hypersensitivity in comparison with sham breathing (p=0.0001). Study 2: Atropine, in comparison with placebo, blocked the attenuating effect of deep breathing on the development of acid-induced oesophageal hypersensitivity (p=0.046).

Conclusions

The development of oesophageal hyperalgesia is prevented by physiologically increasing parasympathetic tone. This effect is pharmacologically blocked with atropine, providing evidence that the PNS influences the development of oesophageal pain hypersensitivity.


Objective

Inhibition of food intake and glucose homeostasis are both promoted when nutrients stimulate enteroendocrine cells (EEC) to release gut hormones. Several specific nutrient receptors may be located on EEC that respond to dietary sugars, amino acids and fatty acids. Bypass surgery for obesity and type II diabetes works by shunting nutrients to the distal gut, where it increases activation of nutrient receptors and mediator release, but cellular mechanisms of activation are largely unknown. We determined which nutrient receptors are expressed in which gut regions and in which cells in mouse and human, how they are associated with different types of EEC, how they are activated leading to hormone and 5-HT release.

Design and results

mRNA expression of 17 nutrient receptors and EEC mediators was assessed by quantitative PCR and found throughout mouse and human gut epithelium. Many species similarities emerged, in particular the dense expression of several receptors in the distal gut. Immunolabelling showed specific colocalisation of receptors with EEC mediators PYY and GLP-1 (L-cells) or 5-HT (enterochromaffin cells). We exposed isolated proximal colonic mucosa to specific nutrients, which recruited signalling pathways within specific EEC extracellular receptor-regulated kinase (p-ERK) and calmodulin kinase II (pCAMKII), as shown by subsequent immunolabelling, and activated release of these mediators. Aromatic amino acids activated both pathways in mouse, but in humans they induced only pCAMKII, which was colocalised mainly with 5-HT expression. Activation was pertussis toxin-sensitive. Fatty acid (C12) potently activated p-ERK in human in all EEC types and evoked potent release of all three mediators.

Conclusions

Specific nutrient receptors associate with distinct activation pathways within EEC. These may provide discrete, complementary pharmacological targets for intervention in obesity and type II diabetes.


Background

Molecular-based companion diagnostic tests are being used with increasing frequency to predict their clinical response to various drugs, particularly for molecularly targeted drugs. However, invasive procedures are typically required to obtain tissues for this analysis. Circulating tumour cells (CTCs) are novel biomarkers that can be used for the prediction of disease progression and are also important surrogate sources of cancer cells. Because current CTC detection strategies mainly depend on epithelial cell-surface markers, the presence of heterogeneous populations of CTCs with epithelial and/or mesenchymal characteristics may pose obstacles to the detection of CTCs.

Methods

We developed a new approach to capture live CTCs among millions of peripheral blood leukocytes using a green fluorescent protein (GFP)-expressing attenuated adenovirus, in which the telomerase promoter regulates viral replication (OBP-401, TelomeScan).

Results

Our biological capturing system can image epithelial and mesenchymal tumour cells with telomerase activities as GFP-positive cells. After sorting, direct sequencing or mutation-specific PCR can precisely detect different mutations in KRAS, BRAF and KIT genes in epithelial, mesenchymal or epithelial–mesenchymal transition-induced CTCs, and in clinical blood samples from patients with colorectal cancer.

Conclusions

This fluorescence virus-guided viable CTC capturing method provides a non-invasive alternative to tissue biopsy or surgical resection of primary tumours for companion diagnostics.


Background

Characterisation of colorectal cancer (CRC) genomes by next-generation sequencing has led to the discovery of novel recurrently mutated genes. Nevertheless, genomic data has not yet been used for CRC prognostication.

Objective

To identify recurrent somatic mutations with prognostic significance in patients with CRC.

Method

Exome sequencing was performed to identify somatic mutations in tumour tissues of 22 patients with CRC, followed by validation of 187 recurrent and pathway-related genes using targeted capture sequencing in additional 160 cases.

Results

Seven significantly mutated genes, including four reported (APC, TP53, KRAS and SMAD4) and three novel recurrently mutated genes (CDH10, FAT4 and DOCK2), exhibited high mutation prevalence (6–14% for novel cancer genes) and higher-than-expected number of non-silent mutations in our CRC cohort. For prognostication, a five-gene-signature (CDH10, COL6A3, SMAD4, TMEM132D, VCAN) was devised, in which mutation(s) in one or more of these genes was significantly associated with better overall survival independent of tumor-node-metastasis (TNM) staging. The median survival time was 80.4 months in the mutant group versus 42.4 months in the wild type group (p=0.0051). The prognostic significance of this signature was successfully verified using the data set from the Cancer Genome Atlas study.

Conclusions

The application of next-generation sequencing has led to the identification of three novel significantly mutated genes in CRC and a mutation signature that predicts survival outcomes for stratifying patients with CRC independent of TNM staging.


Objective

Serum lipase activities above the threefold upper reference limit indicate acute pancreatitis. We investigated whether high lipase activity—within the reference range and in the absence of pancreatitis—are associated with genetic single nucleotide polymorphisms (SNP), and whether these identified SNPs are also associated with clinical pancreatitis.

Methods

Genome-wide association studies (GWAS) on phenotypes ‘serum lipase activity’ and ‘high serum lipase activity’ were conducted including 3966 German volunteers from the population-based Study-of-Health-in-Pomerania (SHIP). Lead SNPs associated on a genome-wide significance level were replicated in two cohorts, 1444 blood donors and 1042 pancreatitis patients.

Results

Initial discovery GWAS detected SNPs within or near genes encoding the ABO blood group specifying transferases A/B (ABO), Fucosyltransferase-2 (FUT2), and Chymotrypsinogen-B2 (CTRB2), to be significantly associated with lipase activity levels in asymptomatic subjects. Replication analyses in blood donors confirmed the association of FUT-2 non-secretor status (OR=1.49; p=0.012) and ABO blood-type-B (OR=2.48; p=7.29x10–8) with high lipase activity levels. In pancreatitis patients, significant associations were found for FUT-2 non-secretor status (OR=1.53; p=8.56x10–4) and ABO-B (OR=1.69, p=1.0x10–4) with chronic pancreatitis, but not with acute pancreatitis. Conversely, carriers of blood group O were less frequently affected by chronic pancreatitis (OR=0.62; p=1.22x10–05) and less likely to have high lipase activity levels (OR=0.59; p=8.14x10–05).

Conclusions

These are the first results indicating that ABO blood type-B as well as FUT2 non-secretor status are common population-wide risk factors for developing chronic pancreatitis. They also imply that, even within the reference range, elevated lipase activities may indicate subclinical pancreatic injury in asymptomatic subjects.


Objective

Antiangiogenic strategies have been proposed as a promising new approach for the therapy of portal hypertension and chronic liver disease. Pigment epithelium-derived factor (PEDF) is a powerful endogenous angiogenesis inhibitor whose role in portal hypertension remains unknown. Therefore, we aimed at determining the involvement of PEDF in cirrhotic portal hypertension and the therapeutic efficacy of its supplementation.

Design

PEDF expression profiling and its relationship with vascular endothelial growth factor (VEGF), neovascularisation and fibrogenesis was determined in bile duct-ligated (BDL) rats and human cirrhotic livers. The ability of exogenous PEDF overexpression by adenovirus-mediated gene transfer (AdPEDF) to inhibit angiogenesis, fibrogenesis and portal pressure was also evaluated in BDL rats, following prevention and intervention trials.

Results

PEDF was upregulated in cirrhotic human and BDL rat livers. PEDF and VEGF protein expression and localisation in mesentery and liver increased in parallel with portal hypertension progression, being closely linked in time and space with mesenteric neovascularisation and liver fibrogenesis in BDL rats. Furthermore, AdPEDF increased PEDF bioavailability in BDL rats, shifting the net balance in the local abundance of positive (VEGF) and negative (PEDF) angiogenesis drivers in favour of attenuation of portal hypertension-associated pathological neovascularisation. The antiangiogenic effects of AdPEDF targeted only pathological angiogenesis, without affecting normal vasculature, and were observed during early stages of disease. AdPEDF also significantly decreased liver fibrogenesis (through metalloproteinase upregulation), portosystemic collateralisation and portal pressure in BDL rats.

Conclusions

This study provides compelling experimental evidence indicating that PEDF could be a novel therapeutic agent worthy of assessment in portal hypertension and cirrhosis.


Background and objective

The off-treatment durability of nucleos(t)ide analogue therapy in Asian hepatitis B e antigen (HBeAg) negative chronic hepatitis B (CHB) and the role of hepatitis B surface antigen (HBsAg) levels in predicting off-treatment durability has not been well investigated.

Methods

Following Asia-Pacific Association for the Study of the Liver guidelines, entecavir was stopped in Asian HBeAg negative patients treated for ≥2 years with undetectable HBV DNA levels on ≥3 separate occasions 6 months apart before treatment cessation. HBsAg and HBV DNA levels were prospectively monitored every 6–12 weeks for 48 weeks. Entecavir was restarted if there was virologic relapse (defined as HBV DNA >2000 IU/mL).

Result

184 patients (mean age 53.9 years, 67.9% male) were recruited. The cumulative rate of virologic relapse at 24 and 48 weeks was 74.2% and 91.4%, respectively. The median HBV DNA level at virologic relapse was 11 000 (range 2115 to >1.98x108) IU/mL. 42 (25.8%) patients had elevated alanine aminotransferase (median level 97 U/L, range 37–1058 U/L) during virologic relapse. Mean rate of off-treatment HBsAg decline was 0.018 (±0.456) log IU/mL/year. No patients cleared HBsAg. There was no correlation between off-treatment serial HBsAg and HBV DNA levels (r=–0.026, p=0.541). HBsAg levels at the time of entecavir commencement, entecavir cessation and the subsequent rate of HBsAg reduction were not associated with virologic relapse (all p>0.05).

Conclusions

Entecavir cessation in Asian HBeAg negative CHB resulted in high rates of virologic relapse, suggesting nucleos(t)ide analogue therapy should be continued indefinitely until the recognised treatment endpoint of HBsAg seroclearance.


Objective

No therapy for non-alcoholic steatohepatitis (NASH) has been approved so far. Roux-en-y gastric bypass (RYGB) is emerging as a therapeutic option, although its effect on NASH and related hepatic molecular pathways is unclear from human studies. We studied the effect of RYGB on pre-existent NASH and hepatic mitochondrial dysfunction—a key player in NASH pathogenesis—in a novel diet-induced mouse model nicely mimicking human disease.

Design

C57BL/6J mice were fed a high-fat high-sucrose diet (HF-HSD).

Results

HF-HSD led to early obesity, insulin resistance and hypercholesterolaemia. HF-HSD consistently induced NASH (steatosis, hepatocyte ballooning and inflammation) with fibrosis already after 12-week feeding. NASH was accompanied by hepatic mitochondrial dysfunction, characterised by decreased mitochondrial respiratory chain (MRC) complex I and IV activity, ATP depletion, ultrastructural abnormalities, together with higher 4-hydroxynonenal (HNE) levels, increased uncoupling protein 2 (UCP2) and tumour necrosis factor-α (TNF-α) mRNA and free cholesterol accumulation. In our model of NASH and acquired mitochondrial dysfunction, RYGB induced sustained weight loss, improved insulin resistance and inhibited progression of NASH, with a marked reversal of fibrosis. In parallel, RYGB preserved hepatic MRC complex I activity, restored ATP levels, limited HNE production and decreased TNF-α mRNA.

Conclusions

Progression of NASH and NASH-related hepatic mitochondrial dysfunction can be prevented by RYGB. RYGB preserves respiratory chain complex activity, thereby restoring energy output, probably by limiting the amount of oxidative stress and TNF-α. These data suggest that modulation of hepatic mitochondrial function contributes to the favourable effect of RYBG on established NASH.


Basic scienceRole of T cell homing receptor GPR15 in colitis: mouse versus man

 Nguyen LP, Pan J, Dinh TT, et al. Role and species-specific expression of colon T cell homing receptor GPR15 in colitis. Nat Immunol 2015;16:207–13.

Recruitment of lymphocytes from the circulation maintains immune homeostasis in the gut while also playing a role in appropriate inflammatory response. This recruitment process is mediated by adhesion and chemoattractant receptors. GPR15 is an HIV coreceptor and an orphan G-protein-coupled receptor with structural homology to known lymphocyte trafficking receptors. Recently, GPR15 was implicated in colon homing of regulatory T (Treg) cells in the mouse; however, its role in effector T cell trafficking and function is unclear. In this study by Nguyen and colleagues, the expression and function of GPR15 on effector T cells in mice and humans was investigated. The authors showed that GPR15 is important for TH1 and TH17...


The incidence of Crohn’s disease (CD) increases steadily in Asia, but is still quite low compared with Western countries.1 So far, over 140 susceptibility loci to CD have been identified in Caucasians through genome-wide association studies (GWASs) and meta-analyses.2 Recent GWASs in Korean and Japanese populations identified a few more susceptibility loci, but could not replicate many established CD loci.3 4 A Japanese large scale replication study consisting of 1311 cases and 6585 controls could replicate less than half of 71 CD susceptibility loci identified in Caucasians.5 Particularly, it aroused concern that such well-established loci as ATG16L1 and NOD2 have not been replicated. It was unclear whether the lack of association was due to limited statistical power, different linkage disequilibrium (LD) structure, or aetiological heterogeneity between Asian and Western populations.

The identification of ATG16L1 as a CD susceptibility gene...


There is a well-established opinion among gastroenterologists from all nations that functional GI disorders and irritable bowel syndrome are the most common diagnoses made in GI clinics and yet represent some of the most challenging patients to manage. The medical mind set is to establish a diagnosis through history, examination and diagnostic tests and to come up with a clear organic explanation for GI disorders. Unfortunately in functional GI disorders, this pathway is often fraught with pitfalls and difficulties and frequently results in endless investigations and fruitless end outcomes for patients in whom no clear organic pathology can be found. Despite all this, it has been known for centuries that there exist people who present with disturbance of gut function without explanation. Such patients remained somewhat of an enigma in those times, but we would now recognise them as having functional GI disorders such as irritable bowel syndrome.


We read with interest the paper by Urribarri et al1 which describes that metalloprotease hyperactivity plays an important role in cyst expansion and that metalloprotease inhibition reduces cyst proliferation. As such, these results help to identify potential drug targets.2 We hypothesise that the expansion and maintenance of the cyst is preceded by mutational events that trigger cytogenesis, and we used genetic analysis to provide additional insight into this process. The majority of polycystic diseases are autosomal dominant disorders where every patient cell possesses one germ line mutation (first hit).3 As somatic second-hit mutations play an important role in liver and renal cyst formation,4–6 it was hypothesised that patients with polycystic disease have a DNA repair defect and accumulate somatic mutations.7 This was supported by a comparative genomic hybridisation study where renal cysts harboured multiple chromosomal aberrations, similar to cancers.


Recently in Gut, Xiao et al1 detailed an extensive analysis of synergistic inhibition of HCV achieved in various in vitro and in vivo models systems when HCV entry inhibitors were combined with different direct acting antivirals (DAA) and host-targeted antiviral. However, a follow-up commentary by Pawlotsky suggested that ‘there is no unmet clinical need’ for the treatment of HCV that cannot be addressed by the HCV drugs currently approved or in late-stage clinical development.2 Here, we comment on the original study and subsequent commentary.

Consistent with the Xiao et al study, we have reported that blocking the HCV entry factor Neimann-Pick-C1-like-1 (NPC1L1) with the Food and Drug Administration (FDA)-approved drug ezetimibe synergistically inhibits chronic HCV infection in vitro when combined with interferon3 and, as we present in figure 1, with HCV DAAs that block intracellular viral production. Importantly, we also showed...


The British Society of Gastroenterology (BSG) guidelines1 on diagnosis and management of coeliac disease (CD) contain much useful information, but in our opinion are badly misleading on the important topic of diagnosis and the relative merits of small intestinal biopsy and serology tests. The authors recommend that a duodenal biopsy is essential for diagnosis in all patients and cannot be replaced by serology alone even in a subset of patients.

Other studies have now confirmed earlier work showing that using an appropriate cut-off for IgA-class anti-tissue transglutaminase antibody (IgA-tTG), the diagnosis can be made with a positive predictive value (PPV) of 100% in a high proportion of adults with CD2 or that with a combination of serological tests biopsy can be avoided in 78% of patients with CD.3 Although generally safe, endoscopy is invasive, expensive, unpleasant, often requires sedation and is time consuming...


Dear Editor,

Increasing evidence suggests that genetic factors play a role in the multifactorial aetiology of liver fibrosis. In their recent paper, Zhao et al1 support this by describing the role of the Jnk1 gene in liver fibrogenesis. Previously, the role of other inflammatory-related genes in the development of liver fibrosis has been described in patients with chronic liver diseases. In patients with chronic hepatitis C, Nalpas et al2 demonstrated a strong association between single nucleotide polymorphisms (SNP) in the interferon gamma receptor 2 (IFNGR2) gene and progression of liver fibrosis. The role of interferon gamma in liver fibrogenesis has been reported before, but the precise mechanism of this effect has not yet been fully elucidated.3 4 Currently, it is not known whether the genetic variants in the IFNGR2 gene also influence liver fibrogenesis in individuals without liver disease. Therefore, we...