Genetic and Inflammatory Biomarkers Classify Small Intestine Inflammation in Asymptomatic First-degree Relatives of Patients With Crohn's Disease.

BACKGROUND & AIMS: Relatives of individuals with Crohn's disease (CD) carry CD-associated genetic variants and are often exposed to environmental factors that increase their risk for this disease. We aimed to estimate the utility of genotype, smoking status, family history, and biomarkers can calculate risk in asymptomatic first-degree relatives of patients with CD. METHODS: We recruited 480 healthy first-degree relatives (full siblings, offspring or parents) of patients with CD through the Guy's and St Thomas' NHS Foundation Trust and from members of Crohn's and Colitis, United Kingdom. DNA samples were genotyped using the Immunochip. We calculated a risk score for 454 participants, based on 72 genetic variants associated with CD, family history, and smoking history. Participants were assigned to highest and lowest risk score quartiles. We assessed pre-symptomatic inflammation by capsule endoscopy and measured 22 markers of inflammation in stool and serum samples (reference standard). Two machine-learning classifiers (elastic net and random forest) were used to assess the ability of the risk factors and biomarkers to identify participants with small intestinal inflammation in the same dataset. RESULTS: The machine-learning classifiers identified participants with pre-symptomatic intestinal inflammation: elastic net (area under the curve, 0.80; 95% CI, 0.62-0.98) and random forest (area under the curve, 0.87; 95% CI, 0.75-1.00). The elastic net method identified 3 variables that can be used to calculate odds for intestinal inflammation: combined family history of CD (odds ratio, 1.31), genetic risk score (odds ratio, 1.14), and fecal calprotectin (odds ratio, 1.04). These same 3 variables were among the 5 factors associated with intestinal inflammation in the random forest model. CONCLUSION: Using machine learning classifiers, we found that genetic variants associated with CD, family history, and fecal calprotectin together identify individuals with pre-symptomatic intestinal inflammation who are therefore at risk for CD. A tool for detecting people at risk for CD before they develop symptoms would help identify the individuals most likely to benefit from early intervention.

Distinct management issues with Crohn's disease of the small intestine.

PURPOSE OF REVIEW: Small bowel Crohn's disease can present with clinical challenges that are specific to its location. In this review, we address some of the areas that present particular problems in small bowel Crohn's disease. RECENT FINDINGS: A key issue specific to small bowel Crohn's disease relates to its diagnosis given that access to the small bowel is limited. Radiological advances, particularly in small bowel ultrasonography and MRI, as well as the introduction of capsule endoscopy and balloon enteroscopy are helping to address this. In addition, our ability to differentiate small bowel Crohn's disease from other causes of inflammation, such as tuberculosis, is improving on the basis of better understanding of the features that differentiate these conditions. It is also becoming apparent that jejunal Crohn's disease represents a distinct disease phenotype with potentially worse clinical outcomes. Finally, because it is a rare complication, our understanding of small bowel cancer associated with Crohn's disease remains limited. Recent publications are, however, starting to improve our knowledge of this condition. SUMMARY: Although small bowel Crohn's disease presents specific management issues not seen in patients with Crohn's disease elsewhere in the gastrointestinal tract, our knowledge of how to manage these is improving.

The prolyl isomerase Pin1 stabilizes NeuroD during differentiation of mechanoreceptors.

The peptidyl prolyl cis-trans isomerase Pin1 plays vital roles in diverse cellular processes and pathological conditions. NeuroD is a differentiation and survival factor for a subset of neurons and pancreatic endocrine cells. Although multiple phosphorylation events are known to be crucial for NeuroD function, their mechanisms remain elusive. In this study, we demonstrate that zebrafish embryos deficient in Pin1 displayed phenotypes resembling those associated with NeuroD depletion, characterized by defects in formation of mechanosensory hair cells. Furthermore, zebrafish Pin1 interacts with NeuroD in a phosphorylation-dependent manner. In Pin1-deficient cell lines, NeuroD is rapidly degraded. However, the protein stability of NeuroD is restored upon overexpression of Pin1. These findings suggest that Pin1 functionally regulates NeuroD protein levels by post-phosphorylation cis-trans isomerization during neuronal specification.

Context-dependent DNA methylation signatures in animal livestock.

DNA methylation is an important epigenetic modification that is widely conserved across animal genomes. It is widely accepted that DNA methylation patterns can change in a context-dependent manner, including in response to changing environmental parameters. However, this phenomenon has not been analyzed in animal livestock yet, where it holds major potential for biomarker development. Building on the previous identification of population-specific DNA methylation in clonal marbled crayfish, we have now generated numerous base-resolution methylomes to analyze location-specific DNA methylation patterns. We also describe the time-dependent conversion of epigenetic signatures upon transfer from one environment to another. We further demonstrate production system-specific methylation signatures in shrimp, river-specific signatures in salmon and farm-specific signatures in chicken. Together, our findings provide a detailed resource for epigenetic variation in animal livestock and suggest the possibility for origin tracing of animal products by epigenetic fingerprinting.

Cholecystitis, Concealment of Hepatobiliary-Pancreatic Pathology: The Role of Endoscopic Retrograde Cholangiopancreatography and Endoscopic Ultrasound.

Cholecystitis is an inflammation of the gallbladder with classic symptoms of right upper quadrant abdominal pain and fever. The most common precipitating factor is cholelithiasis; however, it sometimes appears in conjunction with other hepatobiliary-pancreatic pathology. Management is generally done with antibiotics and supportive care with or without cholecystectomy. The surgical management in practice is often limited by surgery time and patient suitability considering their likely overall outcome. We have outlined two cases with different etiologies presenting as cholecystitis. The aim was to further understand the benefits of multidisciplinary team meetings to optimize patient care and emphasize the roles of endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography in hepatobiliary pathology.

Vedolizumab: early experience and medium-term outcomes from two UK tertiary IBD centres.

OBJECTIVE: To gain an understanding of the efficacy of vedolizumab in a 'real-world' setting. DESIGN: Retrospective cohort study using prospectively maintained clinical records. SETTING: Two UK tertiary inflammatory bowel disease (IBD) centres. PATIENTS: Patients with IBD commenced on vedolizumab at Guy's & St Thomas' and King's College Hospitals during November 2014-November 2015. INTERVENTION: Vedolizumab, a monoclonal antibody to α-4 ß-7 integrins that selectively inhibit leucocyte migration into the gut. MAIN OUTCOME MEASURES: Clinical disease activity was assessed at baseline, weeks 14 and 30 using Harvey-Bradshaw Index (HBI) for Crohn's disease (CD) and Simple Clinical Colitis Activity Index (SCCAI) for ulcerative colitis (UC). Response was defined as HBI or SCCAI reduction ≥3. Remission was defined as HBI <5 or SCCAI <3. Continuous data are summarised as medians, followed by range. RESULTS: Fifty patients were included: 27 CD, 20 UC and 3 IBD-U (included in the UC group for analysis). At baseline visit, the median HBI was 8 (1-16) and SCCAI was 6 (0-15). At week 14, these values had fallen to 5 (0-15) (p=0.117) and 4 (0-10) (p=0.005), respectively. Additionally, week 30 data were available for 19 patients (9 CD, 10 UC). The clinical disease activity scores at that point were HBI 2 (0-7) (p=0.039) and SCCAI 2 (0-10) (p=0.023). At baseline, 37 (74%) of the 50 patients had clinically active disease. Of the patients with active disease, 22 (59%) responded and 14 (38%) achieved remission at week 14. CONCLUSIONS: Our early experience with vedolizumab demonstrates a clear benefit in terms of disease control as well as a steroid-sparing effect in a cohort, which included patients with complex and previously refractory disease.

Getting the best out of thiopurine therapy: thiopurine S-methyltransferase and beyond.

Thiopurines are the cornerstone of treatment for a wide variety of medical disorders, ranging from pediatric leukemia to inflammatory bowel disease. Because of their complex metabolism and potential toxicities, the use of biomarkers to predict risk and response is paramount. Thiopurine S-methyltransferase and thiopurine metabolite levels have emerged as companion diagnostics with crucial roles in facilitating safe and effective treatment. This review serves to update the reader on how these tools are being developed and implemented in clinical practice. A useful paradigm in thiopurine therapeutic strategy is presented, along with fresh insights into the mechanisms underlying these approaches. We elaborate on potential future developments in the optimization of thiopurine therapy.

Optimizing the use of thiopurines in inflammatory bowel disease.

Immunomodulator drugs, of which thiopurines can be considered the backbone, are widely used in the treatment of inflammatory bowel disease. They have been shown to be highly effective and safe; however, a significant proportion of patients are deemed to have a poor response or suffer adverse reactions. Knowing how to monitor and optimize thiopurine therapy in these scenarios is crucial to effective management. We discuss the metabolism of thiopurines, the use of enzyme/metabolite testing to guide treatment, as well as strategies to circumvent toxicity and side effects, such as allopurinol coprescription. The indications, use in pregnancy, safety profile and duration of thiopurine therapy are also discussed.

Deletion of the homeobox gene PRX-2 affects fetal but not adult fibroblast wound healing responses.

The phenotype of fibroblasts repopulating experimental wounds in vivo has been shown to influence both wound healing responses and clinical outcome. Recent studies have demonstrated that the human homeobox gene PRX-2 is strongly upregulated in fibroblasts within fetal, but not adult, mesenchymal tissues during healing. Differential homeobox gene expression by fibroblasts may therefore be important in mediating the scarless healing exhibited in early fetal wounds. RNase protection analysis demonstrated that murine Prx-2 expression was involved in fetal but not adult wound healing responses in vitro. Using fibroblasts established from homozygous mutant (Prx-2-/-) and wild-type (Prx-2+/+) murine skin tissues it was demonstrated that Prx-2 affected a number of fetal fibroblastic responses believed to be important in mediating scarless healing in vivo; namely cellular proliferation, extracellular matrix reorganization, and matrix metalloproteinase 2 and hyaluronic acid production. These data demonstrate how Prx-2 may contribute to the regulation of fetal, but not adult, fibroblasts and ultimately the wound healing phenotype. This study provides further evidence for the importance of homeobox transcription factors in the regulation of scarless wound healing. A further understanding of these processes will, it is hoped, enable the targeting of specific therapies in wound healing, both to effect scarless healing and to stimulate healing in chronic, nonhealing wounds such as venous leg ulcers.

Yolk syncytial layer formation is a failure of cytokinesis mediated by Rock1 function in the early zebrafish embryo.

The yolk syncytial layer (YSL) performs multiple critical roles during zebrafish development. However, little is known about the cellular and molecular mechanisms that underlie the formation of this important extraembryonic structure. Here, we demonstrate by timelapse confocal microscopy of a transgenic line expressing membrane-targeted GFP that the YSL forms as a result of the absence of cytokinesis between daughter nuclei at the tenth mitotic division and the regression of pre-existing marginal cell membranes, thus converting the former margin of the blastoderm into a syncytium. We show that disruption of components of the cytoskeleton induces the formation of an expanded YSL, and identify Rock1 as the regulator of cytoskeletal dynamics that lead to YSL formation. Our results suggest that the YSL forms as a result of controlled cytokinesis failure in the marginal blastomeres, and Rock1 function is necessary for this process to occur. Uncovering the cellular and molecular mechanisms underlying zebrafish YSL formation offers significant insight into syncytial development in other tissues as well as in pathological conditions.

In vivo analysis of choroid plexus morphogenesis in zebrafish.

BACKGROUND: The choroid plexus (ChP), a component of the blood-brain barrier (BBB), produces the cerebrospinal fluid (CSF) and as a result plays a role in (i) protecting and nurturing the brain as well as (ii) in coordinating neuronal migration during neurodevelopment. Until now ChP development was not analyzed in living vertebrates due to technical problems. METHODOLOGY/PRINCIPAL FINDINGS: We have analyzed the formation of the fourth ventricle ChP of zebrafish in the GFP-tagged enhancer trap transgenic line SqET33-E20 (Gateways) by a combination of in vivo imaging, histology and mutant analysis. This process includes the formation of the tela choroidea (TC), the recruitment of cells from rhombic lips and, finally, the coalescence of TC resulting in formation of ChP. In Notch-deficient mib mutants the first phase of this process is affected with premature GFP expression, deficient cell recruitment into TC and abnormal patterning of ChP. In Hedgehog-deficient smu mutants the second phase of the ChP morphogenesis lacks cell recruitment and TC cells undergo apoptosis. CONCLUSIONS/SIGNIFICANCE: This study is the first to demonstrate the formation of ChP in vivo revealing a role of Notch and Hedgehog signalling pathways during different developmental phases of this process.

Wnt signalling mediated by Tbx2b regulates cell migration during formation of the neural plate.

During gastrulation, optimal adhesion and receptivity to signalling cues are essential for cells to acquire new positions and identities via coordinated cell movements. T-box transcription factors and the Wnt signalling pathways are known to play important roles in these processes. Zebrafish tbx2b, a member of the TBX2 family, has previously been shown to be required for the specification of midline mesoderm. We show here that tbx2b transcripts are present during mid-gastrula before its expression is detected by whole-mount in situ hybridization. Isolated ectodermal cells deficient in Tbx2b have altered cell surface properties and the level of cadherins in these cells is lower. In chimaeric embryos generated by cell transplantation and single blastomere injections, Tbx2b-deficient cells are defective in cell movement in a cell-autonomous manner, resulting in their exclusion from the developing neural plate. Using this ;exclusion' phenotype as a screen, we show that Tbx2b acts within the context of Fz7 signalling. The exclusion of cells lacking T-box proteins in chimeras during development was demonstrated with other T-box genes and may indicate a general functional mechanism for T-box proteins.

Ex vivo expanded murine bone marrow cells with a multiple cytokine cocktail retain long-term hematopoietic reconstitution potentials.

BACKGROUND: Although ex vivo expansion of bone marrow (BM) cells has been proposed as an effective method for the early recovery from pancytopenia in patients with bone marrow stem cell transplantation (BMT), the expansion potential and the long-term reconstitution capability of such BM cells is still controversial. We describe here a multiple cytokine medium (MCM) containing major hematopoietic stimulation factors and conditioned medium from PHA-stimulated murine spleen cells that permits the expansion of BM cells with long-term hematopoietic reconstitution capacity. MATERIAL/METHODS: Male murine BM cells were expanded in MCM for 4 to 14 days and injected into lethally irradiated syngeneic female mice. The mice were maintained for 18 months after transplantation for evaluation of hematopoietic reconstitution. RESULTS: The expanded cells contained pluripotent hematopoietic stem cells and lineage committed progenitors as well as terminally differentiated cells. They permitted full recovery of lethally irradiated mice in both early and late stages in same numbers equivalent to that of unexpanded cells. More than 80% of the progenitor cells were donor originated after 18 months. Expanded cells were able to be transduced with a retroviral vector expressing Beta-galactosidase, and continued to express the marker following BMT. CONCLUSIONS: With the use of MCM, the quantity of donor cells from BM and other sources might be greatly reduced. Ex vivo expanded BM cells might also facilitate gene manipulation in vitro by retroviral vectors.

Crystal structure of interleukin-19 defines a new subfamily of helical cytokines.

Interleukin-19 (IL-19) is a novel cytokine that was initially identified during a sequence data base search aimed at finding potential IL-10 homologs. IL-19 shares a receptor complex with IL-20, indicating that the biological activities of these two cytokines overlap and that both may play an important role in regulating development and proper functioning of the skin. We determined the crystal structure of human recombinant IL-19 and refined it at 1.95-A resolution to an R-factor of 0.157. Unlike IL-10, which forms an intercalated dimer, the molecule of IL-19 is a monomer made of seven amphipathic helices, A-G, creating a unique helical bundle. On the basis of the observed structure, we propose that IL-19, IL-20, and other putative members of the proposed IL-10 family together form a distinct subfamily of helical cytokines.