• Home
  • News
  • Calendar
  • About DF/HCC
  • Membership
  • Visitor Center
 

Member Resources

Publications

Gut

Gut RSS feed -- current issue
Gut
The clinical need

Liver disease is an increasing clinical burden, causing over 10 000 deaths last year in the UK alone (http://www.britishlivertrust.org.uk). Liver insufficiency describes the clinical situation in which cumulative (chronic) or one-off massive (acute) insults exceed the liver's normal physiological capacity to functionally regenerate. Untreated, liver insufficiency invariably leads to death. The current gold standard of care in this setting is whole organ transplantation. Due to the increasing burden of disease within the population, however, the number of patients requiring transplantation far exceeds the number of available donor organs. As a result, many patients with liver insufficiency die prematurely.1

Liver cell therapy-intra vs. extra hepatic

The liver is composed of several cell types (endothelial cells, stellate cells, biliary ductal cells, Kupffer cells and natural killer cells) which together provide a supportive niche for the principle cell type—the hepatocyte.2 Treatment...


In many industrialised populations, adenocarcinoma of the oesophagus holds the dubious distinction of being the cancer for which the proportional rise in incidence has been most rapid.1 The factors conferring increased risks are well established, including obesity, gastro-oesophageal acid reflux, smoking and male sex.2 It has also long been known that Barrett's oesophagus, the metaplastic precursor, has a measurable rate of progressing to cancer. This observation has given rise to the notion that screening or surveillance for Barrett's oesophagus should, in theory, reduce the risks of dying from oesophageal adenocarcinoma. However, screening for any cancer is a deceptively tricky business, and while the concept of screening holds considerable intuitive appeal, it is very difficult to establish that any screening programme confers benefits.

Bhat et al3 attempt to infer the effect of a prior diagnosis of Barrett's oesophagus among patients with oesophageal adenocarcinoma, and...


Paediatric cholestasis is a rare but devastating group of diseases that usually manifest in infancy or childhood by impaired bile secretion, due to either primary or secondary alterations affecting the liver secretory machinery, and that may progress to cirrhosis and liver failure. Although there is resemblance in clinical symptoms, the cause of these diseases can be completely different, which is important because it determines, among others, the response to treatment. For a specific subgroup of cholestatic diseases, namely those associated with canalicular transport defects, our pathophysiological understanding has been increased enormously over the last decade. In parallel, treatment options have been developed,1 and the article by Gordo–Gilart et al2 yet takes another step forward.

Several transport proteins located at the canalicular membrane of hepatocytes are required to maintain the correct secretory function of the liver (figure 1). A crucial role is played by...


IBD is characterised by an inappropriate immune response to our own gut microbiota in the setting of a genetically susceptible individual. The consequence of this dysregulated process is activation of the innate immune system which in turn produces cytokines such as tumour necrosis factor α (TNFα) and activation of the adaptive immune system with subsequent recruitment of pro-inflammatory T and B cells to the colon or small bowel. This in turn leads to further amplification of pro-inflammatory cytokines release which bind to cognate receptors and activation of intercellular pathway such as JAK and STAT to mediate tissue inflammation. The mainstay of treatment for individuals with moderate to severe disease UC or Crohn's disease has been therapeutic targeting of the pro-inflammatory cytokine, TNFα. Unfortunately, a significant proportion of individuals will be refractory to these medications or eventually lose efficacy. This has widened the search for other pathways that might be...


Objective

Knowledge of the cellular mechanisms involved in homeostasis of human squamous oesophagus in the steady state and following chronic injury is limited. We aimed to better understand these mechanisms by using a functional 3D approach.

Design

Proliferation, mitosis and the expression of progenitor lineage markers were assessed in normal squamous oesophagus from 10 patients by immunofluorescence on 3D epithelial whole mounts. Cells expressing differential levels of epithelial and progenitor markers were isolated using flow cytometry sorting and characterised by qPCR and IF. Their self-renewing potential was investigated by colony forming cells assays and in vitro organotypic culture models.

Results

Proliferation and mitotic activity was highest in the interpapillary basal layer and decreased linearly towards the tip of the papilla (p<0.0001). The orientation of mitosis was random throughout the basal layer, and asymmetric divisions were not restricted to specific cell compartments. Cells sorted into distinct populations based on the expression of epithelial and progenitor cell markers (CD34 and EpCAM) showed no difference in self-renewal in 2D culture, either as whole populations or as single cells. In 3D organotypic cultures, all cell subtypes were able to recapitulate the architecture of the tissue of origin and the main factor determining the success of the 3D culture was the number of cells plated, rather than the cell type.

Conclusions

Oesophageal epithelial cells demonstrate remarkable plasticity for self-renewal. This situation could be viewed as an ex vivo wounding response and is compatible with recent findings in murine models.


Objective

Endoscopic surveillance of Barrett's oesophagus (BO) provides an opportunity to detect early stage oesophageal adenocarcinoma (OAC). We sought to determine the proportion of OAC patients with a prior diagnosis of BO on a population basis and to evaluate the influence of a prior diagnosis of BO on survival, taking into account lead and length time biases.

Design

A retrospective population-based study of all OAC patients in Northern Ireland between 2003 and 2008. A prior BO diagnosis was determined by linkage to the Northern Ireland BO register. Stage distribution at diagnosis and histological grade were compared between patients with and without a prior BO diagnosis. Overall survival, using Cox models, was compared between patients with and without a prior BO diagnosis. The effect of adjusting the survival differences for histological grade and estimates of lead and length time bias was assessed.

Results

There were 716 OAC cases, 52 (7.3%) of whom had a prior BO diagnosis. Patients with a prior BO diagnosis had significantly lower tumour stage (44.2% vs 11.1% had stage 1 or 2 disease; p<0.001), a higher rate of surgical resection (50.0% vs 25.5%; p<0.001) and had a higher proportion of low/intermediate grade tumours (46.2% vs 26.5%; p=0.011). A prior BO diagnosis was associated with significantly better survival (HR for death 0.39; 95% CI 0.27 to 0.58), which was minimally influenced by adjustment for age, sex and tumour grade (adjusted HR 0.44; 95% CI 0.30 to 0.64). Correction for lead time bias attenuated but did not abolish the survival benefit (HR 0.65; 95% CI 0.45 to 0.95) and further adjustment for length time bias had little effect.

Conclusions

The proportion of OAC patients with a prior diagnosis of BO is low; however, prior identification of BO is associated with an improvement in survival in OAC patients.


Objective

Transducin (β)-like 1 X-linked receptor 1 (TBL1XR1) plays an important role in controlling the precisely regulated switch between gene repression and gene activation in transcriptional regulation. We investigated its biological function and clinical significance in esophageal squamous cell carcinoma (ESCC).

Design

Immunoblotting and immunochemistry were used to determine TBL1XR1 expression in ESCC cell lines, ESCC clinical tissues and 230 clinicopathologically characterised ESCC specimens. The role of TBL1XR1 in lymphangiogenesis and lymphatic metastasis was examined by tube formation, cell invasion and wound-healing assays in vitro, and by a popliteal lymph node metastasis model in vivo. The molecular mechanism by which TBL1XR1 upregulates vascular endothelial growth factor C (VEGF-C) expression was explored using real-time PCR, ELISA, luciferase reporter assay and chromatin immunoprecipitation.

Results

TBL1XR1 expression was significantly upregulated in ESCC, positively correlated with disease stage and patient survival, and identified as an independent prognostic factor for patient outcome. We found that TBL1XR1 overexpression promoted lymphangiogenesis and lymphatic metastasis in ESCC in vitro and in vivo, whereas TBL1XR1 silencing had the converse effect. We demonstrated that TBL1XR1 induced VEGF-C expression by binding to the VEGF-C promoter. We confirmed the correlation between TBL1XR1 and VEGF-C expression in a large cohort of clinical ESCC samples and through analysis of published datasets in gastric, colorectal and breast cancer.

Conclusions

Our results demonstrated that TBL1XR1 induced lymphangiogenesis and lymphatic metastasis in ESCC via upregulation of VEGF-C, and may represent a novel prognostic biomarker and therapeutic target for patients with ESCC.


Objective

Octamer transcription factor 1 (OCT1) was found to be expressed in intestinal metaplasia and gastric cancer (GC), but the exact roles of OCT1 in GC remain unclear. The objective of this study was to determine the functional and prognostic implications of OCT1 in GC.

Design

Expression of OCT1 was examined in paired normal and cancerous gastric tissues and the prognostic significance of OCT1 was analysed by univariate and multivariate survival analyses. The functions of OCT1 on synbindin expression and extracellular signal-regulated kinase (ERK) phosphorylation were studied in vitro and in xenograft mouse models.

Results

The OCT1 gene is recurrently amplified and upregulated in GC. OCT1 overexpression and amplification are associated with poor survival in patients with GC and the prognostic significance was confirmed by independent patient cohorts. Combining OCT1 overexpression with American Joint Committee on Cancer staging improved the prediction of survival in patients with GC. High expression of OCT1 associates with activation of the ERK mitogen-activated protein kinase signalling pathway in GC tissues. OCT1 functions by transactivating synbindin, which binds to ERK DEF domain and facilitates ERK phosphorylation by MEK. OCT1-synbindin signalling results in the activation of ERK substrates ELK1 and RSK, leading to increased cell proliferation and invasion. Immunofluorescent study of human GC tissue samples revealed strong association between OCT1 protein level and synbindin expression/ERK phosphorylation. Upregulation of OCT1 in mouse xenograft models induced synbindin expression and ERK activation, leading to accelerated tumour growth in vivo.

Conclusions

OCT1 is a driver of synbindin-mediated ERK signalling and a promising marker for the prognosis and molecular subtyping of GC.


Objective

Endoscopic surveillance for Barrett's oesophagus (BO) is limited by sampling error and the subjectivity of diagnosing dysplasia. We aimed to compare a biomarker panel on minimal biopsies directed by autofluorescence imaging (AFI) with the standard surveillance protocol to derive an objective tool for dysplasia assessment.

Design

We performed a cross-sectional prospective study in three tertiary referral centres. Patients with BO underwent high-resolution endoscopy followed by AFI-targeted biopsies. 157 patients completed the biopsy protocol. Aneuploidy/tetraploidy; 9p and 17p loss of heterozygosity; RUNX3, HPP1 and p16 methylation; p53 and cyclin A immunohistochemistry were assessed. Bootstrap resampling was used to select the best diagnostic biomarker panel for high-grade dysplasia (HGD) and early cancer (EC). This panel was validated in an independent cohort of 46 patients.

Results

Aneuploidy, p53 immunohistochemistry and cyclin A had the strongest association with dysplasia in the per-biopsy analysis and, as a panel, had an area under the receiver operating characteristic curve of 0.97 (95% CI 0.95 to 0.99) for diagnosing HGD/EC. The diagnostic accuracy for HGD/EC of the three-biomarker panel from AFI+ areas was superior to AFI– areas (p<0.001). Compared with the standard protocol, this panel had equal sensitivity for HGD/EC, with a 4.5-fold reduction in the number of biopsies. In an independent cohort of patients, the panel had a sensitivity and specificity for HGD/EC of 100% and 85%, respectively.

Conclusions

A three-biomarker panel on a small number of AFI-targeted biopsies provides an accurate and objective diagnosis of dysplasia in BO. The clinical implications have to be studied further.


Objective

Wide-field endoscopic mucosal resection (WF-EMR) is an alternative to surgery for treatment of advanced colonic mucosal neoplasia up to 120 mm in size, but has been criticised for its potentially high recurrence rates. We aimed to quantify recurrence at 4 months (early) and 16 months (late) following successful WF-EMR and identify its risk factors and clinical significance.

Design

Ongoing multicentre, prospective, intention-to-treat analysis of sessile or laterally spreading colonic lesions ≥20 mm in size referred for WF-EMR to seven academic endoscopy units. Surveillance colonoscopy (SC) was performed 4 months (SC1) and 16 months (SC2) after WF-EMR, with photographic documentation and biopsy of the scar.

Results

1134 consecutive patients were enrolled when 1000 successful EMRs were achieved, of whom 799 have undergone SC1. 670 were normal. Early recurrent/residual adenoma was present in 128 (16.0%, 95% CI 13.6% to 18.7%). One case was unknown. The recurrent/residual adenoma was diminutive in 71.7% of cases. On multivariable analysis, risk factors were lesion size >40 mm, use of argon plasma coagulation and intraprocedural bleeding. Of 670 with normal SC1, 426 have undergone SC2, with late recurrence present in 17 cases (4.0%, 95% CI 2.4% to 6.2%). Overall, recurrent/residual adenoma was successfully treated endoscopically in 135 of 145 cases (93.1%, 95% CI 88.1% to 96.4%). If the initial EMR was deemed successful and did not contain submucosal invasion requiring surgery, 98.1% (95% CI 96.6% to 99.0%) were adenoma-free and had avoided surgery at 16 months following EMR.

Conclusions

Following colonic WF-EMR, early recurrent/residual adenoma occurs in 16%, and is usually unifocal and diminutive. Risk factors were identified. Late recurrence occurs in 4%. Overall, recurrence was managed endoscopically in 93% of cases. Recurrence is not a significant clinical problem following WF-EMR, as with strict colonoscopic surveillance, it can be managed endoscopically with high success rates.

Trial registration number:

NCT01368289.


Objective

The genetic basis of inflammatory bowel disease (IBD) is incompletely understood. The aim of this study was to identify rare genetic variants involved in the pathogenesis of IBD.

Design

Exome sequencing and immunological profiling were performed in a patient with early onset Crohn's disease (CD). The coding region of the gene encoding X-linked inhibitor of apoptosis protein (XIAP) was sequenced in samples of 275 paediatric IBD and 1047 adult-onset CD patients. XIAP genotyping was performed in samples of 2680 IBD patients and 2864 healthy controls. Functional effects of the variants identified were investigated in primary cells and cultured cell lines.

Results

Our results demonstrate the frequent occurrence of private variants in XIAP in about four percent of male patients with paediatric-onset CD. While XIAP mutations are known to be associated with the primary immunodeficiency (PID) X-linked lymphoproliferative disease type 2 (XLP2), CD patients described here exhibited intestinal inflammation in the absence of XLP2 and harboured a spectrum of mutations partially distinct from that observed in XLP2. The majority of XIAP variants identified was associated with a selective defect in NOD1/2 signalling, impaired NOD1/2-mediated activation of NF-B, and altered NF-B-dependent cytokine production.

Conclusions

This study reveals the unanticipated, frequent occurrence of XIAP variants in male paediatric-onset CD. The link between XIAP and NOD1/2, and the association of XIAP variants with XLP2, support the concept of PID in a subset of IBD patients. Moreover, these studies provide a rationale for the implementation of XIAP sequencing in clinical diagnostics in male patients with severe CD.


Objective

The α4β7 integrin monoclonal antibody vedolizumab is hypothesised to be gut selective. Effects of vedolizumab on immune responses to parenterally or enterally administered antigens were investigated.

Design

In this randomised, double-blind, placebo-controlled, phase I trial, healthy participants received a single intravenous dose of vedolizumab 750 mg (n=64) or placebo (n=63). After 4 days, participants began intramuscular hepatitis B vaccine (HBV; days 4, 32, 60) and oral cholera vaccine (OCV; days 4, 18) regimens. The study was designed to demonstrate a 15% non-inferiority margin for the between-group difference in the primary end point: percentage of participants with HBV seroconversion at day 74 (serum hepatitis B surface antigen (HBs) antibody titre ≥10 IU/L). OCV seroconversion at day 74 (>4-fold increase in serum cholera toxin (CT) antibodies) was a secondary end point.

Results

A total of 56 (90.3%) placebo-treated and 54 (88.5%) vedolizumab-treated participants responded to HBV. Geometric mean anti-HBs titres were similar for placebo (114.4 IU/L) and vedolizumab (129.6 IU/L) at day 74. A total of 60 (96.8%) placebo-treated and 52 (82.5%) vedolizumab-treated participants responded to OCV at day 74. Geometric mean anti-CT IgG levels were higher for placebo than for vedolizumab at day 74 (9210.08 vs 3007.8 ELISA Units (EU)/mL) and day 32 (11629.3 vs 1575.4 EU/mL). Anti-CT IgA results were similar. Adverse events were consistent with previous experience. One serious adverse event (spontaneous abortion) was reported for placebo.

Conclusions

Vedolizumab did not alter the response to parenterally administered antigens but reduced the response to oral antigens, demonstrating its gut-selective mechanism of action.

Trial registration number

NCT Number: 01981616; EudraCT Number: 2011-001874-24.


Objective

Bile acids may play a role in the pathogenesis of IBS. We investigated the potential effects of bile acids entering the colon and its role in the symptom pattern in IBS.

Design

We measured 75Se-labelled homocholic acid-taurine (75SeHCAT) retention, and serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor (FGF) 19 in patients with IBS (n=141) and control subjects (75SeHCAT n=29; C4 and FGF19 n=435). In patients with IBS stool frequency and form, as well as GI symptom severity were registered, and in a proportion of patients colonic transit time and rectal sensitivity were measured (n=66). An 8-week open-label treatment with colestipol was offered to patients with 75SeHCAT <20%, and the effect of treatment was evaluated with IBS severity scoring system and adequate relief of IBS symptoms.

Results

Compared with controls, patients with IBS had lower 75SeHCAT values (p=0.005), higher C4c levels (C4 corrected for cholesterol) (p<0.001), but similar FGF19 levels. Abnormal 75SeHCAT retention (<10%) was seen in 18% of patients, whereas 23% had elevated C4c levels. Patients with IBS with 75SeHCAT retention <10% had more frequent stools, accelerated colonic transit time, rectal hyposensitivity, a higher body mass index, higher C4c and lower FGF19 levels. Colestipol treatment improved IBS symptoms (IBS severity scoring system 220±109 vs 277±106; p<0.01), and 15/27 patients fulfilled criteria for treatment response (adequate relief ≥50% of weeks 5–8).

Conclusions

Increased colonic bile acid exposure influences bowel habit and colonic transit time in patients with IBS. A high response rate to open label treatment with colestipol supports this, but placebo-controlled studies are warranted.


Objective

A low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) diet reduces symptoms of IBS, but reduction of potential prebiotic and fermentative effects might adversely affect the colonic microenvironment. The effects of a low FODMAP diet with a typical Australian diet on biomarkers of colonic health were compared in a single-blinded, randomised, cross-over trial.

Design

Twenty-seven IBS and six healthy subjects were randomly allocated one of two 21-day provided diets, differing only in FODMAP content (mean (95% CI) low 3.05 (1.86 to 4.25) g/day vs Australian 23.7 (16.9 to 30.6) g/day), and then crossed over to the other diet with ≥21-day washout period. Faeces passed over a 5-day run-in on their habitual diet and from day 17 to day 21 of the interventional diets were pooled, and pH, short-chain fatty acid concentrations and bacterial abundance and diversity were assessed.

Results

Faecal indices were similar in IBS and healthy subjects during habitual diets. The low FODMAP diet was associated with higher faecal pH (7.37 (7.23 to 7.51) vs 7.16 (7.02 to 7.30); p=0.001), similar short-chain fatty acid concentrations, greater microbial diversity and reduced total bacterial abundance (9.63 (9.53 to 9.73) vs 9.83 (9.72 to 9.93) log10 copies/g; p<0.001) compared with the Australian diet. To indicate direction of change, in comparison with the habitual diet the low FODMAP diet reduced total bacterial abundance and the typical Australian diet increased relative abundance for butyrate-producing Clostridium cluster XIVa (median ratio 6.62; p<0.001) and mucus-associated Akkermansia muciniphila (19.3; p<0.001), and reduced Ruminococcus torques.

Conclusions

Diets differing in FODMAP content have marked effects on gut microbiota composition. The implications of long-term reduction of intake of FODMAPs require elucidation.

Trial registration number

ACTRN12612001185853.


Objective

To estimate risk of colorectal cancer (CRC) for first-degree relatives of CRC cases based on CRC molecular subtypes and tumour pathology features.

Design

We studied a cohort of 33 496 first-degree relatives of 4853 incident invasive CRC cases (probands) who were recruited to the Colon Cancer Family Registry through population cancer registries in the USA, Canada and Australia. We categorised the first-degree relatives into four groups: 28 156 of 4095 mismatch repair (MMR)-proficient probands, 2302 of 301 MMR-deficient non-Lynch syndrome probands, 1799 of 271 suspected Lynch syndrome probands and 1239 of 186 Lynch syndrome probands. We compared CRC risk for first-degree relatives stratified by the absence or presence of specific tumour molecular pathology features in probands across each of these four groups and for all groups combined.

Results

Compared with first-degree relatives of MMR-proficient CRC cases, a higher risk of CRC was estimated for first-degree relatives of CRC cases with suspected Lynch syndrome (HR 2.06, 95% CI 1.59 to 2.67) and with Lynch syndrome (HR 5.37, 95% CI 4.16 to 6.94), but not with MMR-deficient non-Lynch syndrome (HR 1.04, 95% CI 0.82 to 1.31). A greater risk of CRC was estimated for first-degree relatives if CRC cases were diagnosed before age 50 years, had proximal colon cancer or if their tumours had any of the following: expanding tumour margin, peritumoral lymphocytes, tumour-infiltrating lymphocytes or synchronous CRC.

Conclusions

Molecular pathology features are potentially useful to refine screening recommendations for first-degree relatives of CRC cases and to identify which cases are more likely to be caused by genetic or other familial factors.


Objective

Capecitabine is an oral 5-fluorouracil (5-FU) pro-drug commonly used to treat colorectal carcinoma and other tumours. About 35% of patients experience dose-limiting toxicity. The few proven genetic biomarkers of 5-FU toxicity are rare variants and polymorphisms, respectively, at candidate loci dihydropyrimidine dehydrogenase (DPYD) and thymidylate synthase (TYMS).

Design

We investigated 1456 polymorphisms and rare coding variants near 25 candidate 5-FU pathway genes in 968 UK patients from the QUASAR2 clinical trial.

Results

We identified the first common DPYD polymorphisms to be consistently associated with capecitabine toxicity, rs12132152 (toxicity allele frequency (TAF)=0.031, OR=3.83, p=4.31x10–6) and rs12022243 (TAF=0.196, OR=1.69, p=2.55x10–5). rs12132152 was particularly strongly associated with hand-foot syndrome (OR=6.1, p=3.6x10–8). The rs12132152 and rs12022243 associations were independent of each other and of previously reported DPYD toxicity variants. Next-generation sequencing additionally identified rare DPYD variant p.Ala551Thr in one patient with severe toxicity. Using functional predictions and published data, we assigned p.Ala551Thr as causal for toxicity. We found that polymorphism rs2612091, which lies within an intron of ENOSF1, was also associated with capecitabine toxicity (TAF=0.532, OR=1.59, p=5.28x10–6). ENSOF1 is adjacent to TYMS and there is a poorly characterised regulatory interaction between the two genes/proteins. Unexpectedly, rs2612091 fully explained the previously reported associations between capecitabine toxicity and the supposedly functional TYMS variants, 5'VNTR 2R/3R and 3'UTR 6 bp ins-del. rs2612091 genotypes were, moreover, consistently associated with ENOSF1 mRNA levels, but not with TYMS expression.

Conclusions

DPYD harbours rare and common capecitabine toxicity variants. The toxicity polymorphism in the TYMS region may actually act through ENOSF1.


Objective

Since the publication of the first Asia Pacific Consensus on Colorectal Cancer (CRC) in 2008, there are substantial advancements in the science and experience of implementing CRC screening. The Asia Pacific Working Group aimed to provide an updated set of consensus recommendations.

Design

Members from 14 Asian regions gathered to seek consensus using other national and international guidelines, and recent relevant literature published from 2008 to 2013. A modified Delphi process was adopted to develop the statements.

Results

Age range for CRC screening is defined as 50–75 years. Advancing age, male, family history of CRC, smoking and obesity are confirmed risk factors for CRC and advanced neoplasia. A risk-stratified scoring system is recommended for selecting high-risk patients for colonoscopy. Quantitative faecal immunochemical test (FIT) instead of guaiac-based faecal occult blood test (gFOBT) is preferred for average-risk subjects. Ancillary methods in colonoscopy, with the exception of chromoendoscopy, have not proven to be superior to high-definition white light endoscopy in identifying adenoma. Quality of colonoscopy should be upheld and quality assurance programme should be in place to audit every aspects of CRC screening. Serrated adenoma is recognised as a risk for interval cancer. There is no consensus on the recruitment of trained endoscopy nurses for CRC screening.

Conclusions

Based on recent data on CRC screening, an updated list of recommendations on CRC screening is prepared. These consensus statements will further enhance the implementation of CRC screening in the Asia Pacific region.


Objective

To characterise the relationship between simvastatin and risk of acute pancreatitis (AP).

Design

We conducted a retrospective cohort study (2006–2012) on data from an integrated healthcare system in southern California. Exposure to simvastatin was calculated from time of initial dispensation until 60 days following prescription termination. AP cases were defined by ICD-9 CM 577.0 and serum lipase≥3 times normal. Patients were censored at death, last follow-up, and onset of AP or end-of-study. Incidence rate of pancreatitis among simvastatin users was compared with the adult reference population. Robust Poisson regression was used to generate risk ratio (RR) estimates for simvastatin use adjusted for age, gender, race/ethnicity, gallstone-related disorders, hypertriglyceridaemia, smoking and alcohol dependence. Analysis was repeated for atorvastatin.

Results

Among 3 967 859 adult patients (median duration of follow-up of 3.4 years), 6399 developed an initial episode of AP. A total of 707 236 patients received simvastatin during the study period. Patients that received simvastatin were more likely to have gallstone-related disorders, alcohol dependence or hypertriglyceridaemia compared with the reference population. Nevertheless, risk of AP was significantly reduced with simvastatin use, crude incidence rate ratio 0.626 (95% CL 0.588, 0.668), p<0.0001. In multivariate analysis, simvastatin was independently associated with reduced risk of pancreatitis, adjusted RR 0.29 (95% CL 0.27, 0.31) after adjusting for age, gender, race/ethnicity, gallstone disorders, alcohol dependence, smoking and hypertriglyceridaemia. Similar results were noted with atorvastatin, adjusted RR 0.33(0.29, 0.38).

Conclusions

Use of simvastatin was independently associated with reduced risk of AP in this integrated healthcare setting. Similar findings for atorvastatin suggest a possible class effect.


Objective

The antiviral efficacy of nucleos(t)ide analogues whose main limitation is relapse after discontinuation requires long-term therapy. To overcome the risk of relapse and virological breakthrough during long-term therapy, we performed a phase I/II, open, prospective, multicentre trial using a HBV envelope-expressing DNA vaccine.

Design

70 patients treated effectively with nucleos(t)ide analogues for a median of 3 years (HBV DNA <12 IU/mL for at least 12 months) were randomised into two groups: one received five intramuscular injections of vaccine (weeks 0, 8, 16, 40 and 44) and one did not receive the vaccine. Analogues were stopped after an additional 48 weeks of treatment in patients who maintained HBV DNA <12 IU/mL with no clinical progression and monthly HBV DNA for 6 months. The primary endpoint was defined as viral reactivation at week 72 (HBV DNA >120 IU/mL) or impossibility of stopping treatment at week 48.

Results

Reactivation occurred in 97% of each group after a median 28 days without liver failure but with an HBV DNA <2000 IU/mL in 33%; 99% of adverse reactions were mild to moderate. Immune responses were evaluated by enzyme-linked immunosorbent spot and proliferation assays: there was no difference in the percentage of patients with interferon- secreting cells and a specific T-cell proliferation to HBcAg but not to HBsAg after reactivation in each group.

Conclusions

Although it is fairly well tolerated, the HBV DNA vaccine does not decrease the risk of relapse in HBV-treated patients or the rate of virological breakthrough, and does not restore the anti-HBV immune response despite effective viral suppression by analogues.

Trial registration number

NCT00536627.


Objective

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a potentially lethal autosomal recessive liver disease associated with mutations in ABCB4, the gene encoding the canalicular translocator of phosphatidylcholine MDR3. While some affected children benefit from ursodeoxycholic acid (UDCA) therapy, others evolve to end-stage liver disease. We aimed to evaluate whether these different outcomes are related to the impact of ABCB4 mutations.

Design

Six children with PFIC3 were investigated by sequencing of ABCB4 exons and flanking intron-exon boundaries and by immunohistochemistry. ABCB4 missense mutations were phenotyped in vitro by assessing their effects on MDR3 expression, subcellular localisation, and phosphatidylcholine-translocating activity. The resulting data were contrasted with the clinical outcomes.

Results

Eight distinct ABCB4 mutations were identified: one nonsense, one splicing and six missense mutations, four of which (G68R, T201M, P479L, D459H) affected MDR3 expression level. G68R and D459H also led to retention of the protein in endoplasmic reticulum. Phosphatidylcholine efflux assays indicated that T201M, P479L, S978P and E1118K mutations impaired MDR3 activity to variable degrees. Three children with mutations that caused a total loss of MDR3 expression/function manifested progressive liver disease refractory to UDCA treatment. This was also the case in a patient carrying two different mutations that, in combination, resulted in a 90% reduction in total MDR3 activity. A favourable response to UDCA was achieved in two patients with estimated MDR3 activities of 50% and 33%, respectively.

Conclusions

These data provide experimental evidence of the correlation between the degree of MDR3 floppase activity and the clinical outcomes of PFIC3.


Objective

Liver tumour-initiating cells (T-ICs) are critical for hepatocarcinogenesis. However, the underlying mechanism regulating the function of liver T-ICs remains unclear.

Methods

Tissue microarrays containing 242 hepatocellular carcinoma (HCC) samples were used for prognostic analysis. Magnetically activated cell sorting was used to isolate epithelial cell adhesion molecule (EPCAM)-positive cells. The gene expressions affected by miR-429 were determined by arrays. Co-immunoprecipitation was used to study interactions among retinoblastoma protein (RB1), Rb binding protein 4 (RBBP4) and E2F transcription factor 1 (E2F1). The DNA methylation status in CpG islands was detected by quantitative methylation analysis. miRNAs in microvesicles were isolated by a syringe filter system.

Results

The significant prognosis factor miR-429 was upregulated in HCC tissues and also in primary liver T-ICs isolated from clinical samples. The enrichment of miR-429 in EPCAM+ T-ICs contributed to hepatocyte self-renewal, malignant proliferation, chemoresistance and tumorigenicity. A novel functional axis involving miR-429, RBBP4, E2F1 and POU class 5 homeobox 1 (POU5F1 or OCT4) governing the regulation of liver EPCAM+ T-ICs was established in vitro and in vivo. The molecular mechanism regulating miR-429 expression, involving four abnormal hypomethylated sites upstream of the miR-200b/miR-200a/miR-429 cluster, was first defined in both EPCAM+ liver T-ICs and very early-stage HCC tissues. miR-429 secreted by high-expressing cells has the potential to become a proactive signalling molecule to mediate intercellular communication.

Conclusions

Epigenetic modification of miR-429 can manipulate liver T-ICs by targeting the RBBP4/E2F1/OCT4 axis. This miRNA might be targeted to inactivate T-ICs, thus providing a novel strategy for HCC prevention and treatment.


Objective

Impaired adaptive response to oxidative injuries is a fundamental mechanism central to the pathogenesis of chronic hepatitis C (CHC). Glycogen synthase kinase (GSK) 3β is an indispensable regulator of the oxidative stress response. However, the exact role of GSK3β in CHC is uncertain and was examined.

Design

GSK3β and Nrf2 signalling pathways were examined in JFH1 HCV infected Huh7.5.1 hepatocytes, and also in liver biopsy specimens from CHC patients.

Results

HCV infection elicited prominent Nrf2 antioxidant response in hepatocytes, marked by elevated expression of the Nrf2-dependent molecule haem oxygenase-1 and subsequent protection from apoptotic cell death. Inhibitory phosphorylation of GSK3β seems to be essential and sufficient for HCV-induced Nrf2 response. Mechanistically, GSK3β associated and physically interacted with Nrf2 in hepatocytes. In silico analysis revealed that Nrf2 encompasses multiple GSK3β phosphorylation consensus motifs, denoting Nrf2 as a cognate substrate of GSK3β. In the presence of TGFβ1, the HCV-induced GSK3β phosphorylation was blunted via a protein phosphatase 1-dependent mechanism and the cytoprotective Nrf2 response drastically impaired. This effect was counteracted by lithium, a selective inhibitor of GSK3β. In liver biopsy specimens from CHC patients, the expression of phosphorylated GSK3β positively correlated with Nrf2 expression and was inversely associated with the degree of liver injury. Moreover, CHC patients who received long-term lithium carbonate therapy primarily for concomitant psychiatric disorders exhibited much less liver injury, associated with enhanced hepatic expression of Nrf2.

Conclusions

Inhibition of GSK3β exerts hepatoprotection in CHC possibly through its direct regulation of Nrf2 antioxidant response.


Clinical presentation

A 63-year-old woman was admitted to our gastroenterology unit to undergo a screening colonoscopy, scheduled for faecal occult blood test positivity. During the procedure, a flat, rectal granular lesion was found. With the use of magnification and narrow band image (NBI) technology, the lesion was diagnosed as a laterally spreading tumour (LST), granular mixed type, 30 mm in maximum diameter (figure 1). The pit pattern was unclassifiable and vascular pattern was similar to the type IV of the classification proposed by Inoue regarding the microvasculature pattern of the oesophagus for diagnosis and evaluation of the squamous cell carcinoma. The type IV shows initial irregularity and dilated intra-papillary capillary loops and indicates benign change such as low-grade dysplasia with a probability of approximately 50% (figure 2).1 The lesion involved half of the circumference of the rectum and the dentate line and the anal squamous...


Basic scienceCan we understand how the gut microbiota is established?

Seedorf H, Griffin NW, Ridaura VK, et al. Bacteria from diverse habitats colonise and compete in the mouse gut. Cell 2014;159:253–66.

How microbes establish themselves within our GI tract and how our interactions with other humans, animals and our environment impacts on this colonisation remains unknown. Understanding how microbes establish themselves could provide strong clues as to how our gut microbiota shapes our health, and potentially could identify how well-defined species consortia (microbiota-directed therapeutics) could be beneficial. In this study, bacteria from several foreign environments were used to colonise germ-free mice, and their ability to metabolise dietary and host carbohydrates and bile acids were measured. The findings demonstrate that the mouse intestinal tract, while highly selective, shows unanticipated patterns of ecological succession. Nonetheless, cohousing the various colonised mice revealed that most bacterial phylotypes, including those from...


We read with interest the two excellent studies on interval colorectal cancers (CRC) following colonoscopy and wish to present important data relevant to the prevention of interval CRC. In a pooled multicohort analysis, Robertson and coauthors found that invasive cancer was diagnosed in 0.6% of patients after clearing colonoscopy among eight large North American trials, and concluded that half of these were likely missed lesions.1 In a population-based study, le Clercq and coauthors reported that CRC found following colonoscopy were more likely to have non-polypoid morphology than prevalent cancers.2

We previously described that non-polypoid colorectal neoplasms (NP-CRN) harbour more advanced pathology than polypoid neoplasms.3 Indeed, due to their subtle appearance, NP-CRN may be a key contributor to interval CRC. The learning curve in their detection is largely unknown.

Using available data, we summarised the learning curve (see figure 1) for...


We read with great interest van Bodegraven et al's1 paper about the treatment of osteopenia in patients with Crohn's disease. They have identified an evidence gap, as many studies of interventions to treat osteoporosis and prevent bone loss have been conducted on older and primarily female patients. In contrast, both male and female patients with Crohn's disease may develop osteopenia and osteoporosis at a younger age. The authors found that use of risedronate can improve bone density in the lumbar spine of patients with Crohn's disease.

One of the exclusion criteria for patients in this study was vitamin D deficiency. Vitamin D deficiency has previously been noted to be common in patients with Crohn's disease.2 Vitamin D deficiency in patients with Crohn's disease has been known to correlate with bone loss for some time.3 Patients with Crohn's disease who are vitamin D...


We read with interest the comments of Buchan and Manuel concerning our risedronate intervention trial in osteopenic patients with Crohn's disease.1 2

They stipulated that exclusion of patients with vitamin D deficiency limited the significance of the performed study, as this deficiency is frequently observed in Crohn's disease. It is however well known that replenishment of vitamin D (and calcium) in patients with vitamin D deficiency would lead to a rapid improvement of bone density, irrespective of any effect of risedronate. As assessment of a therapeutic effect of the latter was our primary study aim, we decided to exclude patients with vitamin D deficiency.

In addition to their observation that present-day treatment strategies for osteopenia in patients with Crohn's disease are primarily based on suboptimal study data, a recent meta-analysis from 19 randomised controlled trials concerning low bone mineral density in patients with IBD, though...


Liu et al1 have to be commended for their recent report concerning the predictive value of hepatitis B virus (HBV) seromarkers clearance for hepatocellular carcinoma (HCC) risk in the REVEAL study. There are, however, some limits and interrogations:

  • The incidence rates of HCC are measured from baseline (as the characteristics of the patients) and not from the first occurrence of seromarkers clearance, causing probably an underestimation of the protective roles of the clearances of HBsAg and HBV DNA against HCC occurrence. In other words, the predictive value of the duration of seromarkers positivity could be a better indicator of the risk of HCC that the seromarkers state at the end of the follow-up.

  • The figure describing the HCC cumulative lifetime incidence is frightening, but is it the reality? As this figure does not take into account other important predictive factors of HCC, such as age...


  • We would like to respond to Dr Pariente's letter, which addresses our recently reported results regarding the seroclearance of HBV seromarkers and subsequent risk for hepatocellular carcinoma (HCC).1 2 Unfortunately, his comments are based on serious misunderstandings of our findings.

    First, he suggests that there may be underestimation of the protective roles of marker seroclearance, since incidence rates of HCC were measured from baseline, and that the duration of seromarkers’ positivity would be a better indicator of HCC risk. In order to truly measure the effect of HBV DNA and Hepatitis B surface Antigen (HBsAg) seroclearance on HCC incidence, we would need a large cohort of individuals followed up since birth for subsequent outcomes. However, this was not feasible in this study. Thus, left truncation that often occurs in cohort studies may have resulted in some underestimation of effect. However, the number of cases...


    With great interest we have read the paper by Rungoe et al1 describing a possible decrease rate in surgery in patients with IBD. The authors have identified all Danish patients with IBD by their first IBD diagnosis registered in the time period from 1979 to 2011. Data were extracted from the Danish National Patient Register, which contains information about all inpatient hospital contacts including diagnoses and surgical interventions, and outpatient diagnoses were not registered before 1995. Accordingly, Cohorts 1 and 2 represent only patients, who have had conditions requiring first time admissions, whereas Cohorts 3 and 4 represent a mixture of patients having first time diagnoses of IBD as inpatients or as outpatients (probably milder cases). Thus, Cohorts 3 and 4 might represent patients with less severe disease at the time of IBD diagnosis, compared with Cohorts 1 and 2.

    This fact may induce some bias...


    To the Editor,

    We thank Dr Tøttrup and colleagues for their comments1 on our recent paper on decreasing risk of surgery over time among Danish patients with IBD.2 We agree with the authors that it is not certain the observed decrease in surgery is explained by the parallel changes in medication use. However, results do not reflect the fact that outpatients were included in later cohorts. This was tested thoroughly and—as described in the paper—restricting analyses to inpatients only, we obtained nearly identical results. In other words, even among inpatients, a statistically significant decrease in surgery over time was observed.

    Correction notice

    The title of this letter has changed since published Online First.

    Contributors

    Both authors contributed equally in this manuscript.

    Competing interests

    None.

    Provenance and peer review

    Not commissioned; internally peer reviewed.