Persistence of endocrine disruption in zebrafish (Danio rerio) after discontinued exposure to the androgen 17β-trenbolone.

The aim of the present study was to investigate the effects of the androgenic endocrine disruptor 17β-trenbolone on the sexual development of zebrafish (Danio rerio) with special emphasis on the question of whether adverse outcomes of developmental exposure are reversible or persistent. An exposure scenario including a recovery phase was chosen to assess the potential reversibility of androgenic effects. Zebrafish were exposed to environmentally relevant concentrations of 17β-trenbolone (1 ng/L-30 ng/L) from fertilization until completion of gonad sexual differentiation (60 d posthatch). Thereafter, exposure was either followed by 40 d of recovery in clean water or continued until 100 d posthatch, the age when zebrafish start being able to reproduce. Fish exposed for 100 d to 10 ng/L or 30 ng/L 17β-trenbolone were masculinized at different biological effect levels, as evidenced from a concentration-dependent shift of the sex ratio toward males as well as a significantly increased maturity of testes. Gonad morphological masculinization occurred in parallel with decreased vitellogenin concentrations in both sexes. Changes of brain aromatase (cyp19b) mRNA expression showed no consistent trend with respect to either exposure duration or concentration. Gonad morphological masculinization as well as the decrease of vitellogenin persisted after depuration over 40 d in clean water. This lack of recovery suggests that androgenic effects on sexual development of zebrafish are irreversible.

Reversibility of endocrine disruption in zebrafish (Danio rerio) after discontinued exposure to the estrogen 17α-ethinylestradiol.

The aim of the present study was to investigate the persistence of the feminizing effects of discontinued 17α-ethinylestradiol (EE2) exposure on zebrafish (Danio rerio). An exposure scenario covering the sensitive phase of sexual differentiation, as well as final gonad maturation was chosen to examine the estrogenic effects on sexual development of zebrafish. Two exposure scenarios were compared: continuous exposure to environmentally relevant concentrations (0.1-10 ng/L EE2) up to 100 days post-hatch (dph) and developmental exposure up to 60 dph, followed by 40 days of depuration in clean water. The persistence of effects was investigated at different biological organization levels from mRNA to population-relevant endpoints to cover a broad range of important parameters. EE2 had a strong feminizing and inhibiting effect on the sexual development of zebrafish. Brain aromatase (cyp19b) mRNA expression showed no clear response, but vitellogenin levels were significantly elevated, gonad maturation and body growth were inhibited in both genders, and sex ratios were skewed towards females and undifferentiated individuals. To a large extent, all of these effects were reversed after 40 days of recovery, leading to the conclusion that exposure to the estrogen EE2 results in very strong, but reversible underdevelopment and feminization of zebrafish. The present study is the first to show this reversibility at different levels of organization, which gives better insight into the mechanistic basis of estrogenic effects in zebrafish.

Factors Associated with Durable Response to Infliximab in Crohnʼs Disease 5 Years and Beyond: A Multicenter International Cohort

BACKGROUND: Infliximab (IFX) has been used for over a decade worldwide. Less is known about the natural history of IFX use beyond a few years and which patients are more likely to sustain benefits. METHODS: Patients with Crohn's disease (CD) exposed to IFX from Massachusetts General Hospital, Boston, Saint-Antoine Hospital, Paris, and the Swiss IBD Cohort Study were identified through retrospective and prospective data collection, complemented by chart abstraction of electronic medical records. We compared long-term users of IFX (>5 yr of treatment, long-term users of infliximab [LTUI]), with non-LTUI patients to identify prognostic factors. RESULTS: We pooled data on 1014 patients with CD from 3 different databases, of whom 250 were defined as LTUI. The comparison group comprised 290 patients with CD who discontinued IFX: 48 primary nonresponses, 95 loss of responses, and 147 adverse events. Factors associated with LTUI were colonic involvements and an earlier age at the start of IFX. The prevalence of active smokers and obese patients differed markedly, but inversely, between American and European centers but did not impact outcome. The discontinuation rate was stable around 3% to 6%, each year from years 3 to 10. CONCLUSIONS: Young age at start of IFX and colonic CD are factors associated with a beneficial long-term use of IFX. After 5 years of IFX, there is still a 3% to 5% discontinuation rate annually. Several factors associated with a good initial response such as nonsmoker and shorter disease duration at IFX initiation do not seem associated with a longer term response.

CD62L (L-selectin) shedding for assessment of functional blockade of TNF alpha in anti-TNF treated IBD patients: clinical feasibility and perspectives (DOP060)

Background Tumor necrosis factor (TNF) inhibition is central to the therapy of inflammatory bowel diseases (IBD). However, loss of response (LOR) is frequent and additional tests to help decision making with costly anti-TNF Therapy are needed. Methods Consecutive IBD Patients receiving anti-TNF therapy (Infliximab (IFX) or Adalimumab (after IFX LOR) from Bern University Hospital were identified and followed prospectively. Patient whole blood was stimulated with a dose-titration of two triggers of TLR receptors human: TNF and LPS. Median fluorescence intensity of CD62L on the surface of granulocytes was quantified by surface staining with specific antibodies (CD33, CD62L) and flow cytometry and logistic curves to these data permits the calculation of EC50 or the half maximal effective concentration TNF concentration to induce shedding [1]. A shift in the concentration were CD62L shedding occurred was seen before and after the anti-TNF agent administraion which permits to predict the response to the drug. This predicted response was correlated to the clinical evolution of the patients in order to analyze the ability of this test to identify LOR to IFX. Results We collected prospective clinical data and blood samples, before and after anti-TNF agent administration, on 33 IBD patients, 25 Crohn's disease and 8 ulcerative colitis patients (45% females) between June 2012 and November 2013. The assay showed a functional blockade of IFX (PFR) for 22 patients (17 CD and 5 UC) whereas 11 (8 CD and 3 UC) had no functional response (NR) to IFX. Clinical characteristics (e.g. diagnosis, disease location, smoking status, BMI and number of infusions) were no significantly different between predicted PFR and NR. Among the 22 Patients with PRF, only 1 patient was a clinical non responder (LOR to IFX), based on clinical prospective evaluation by IBD gastroenterologists (PJ, AM), and among the 11 predicted NR, 3 had no clinical LOR. Sensitivity of this test was 95% and specificity 73% and AUC adjusted for age and gender was 0.81 (Figure 1). During follow up (median 10 mo, 3–15) 8 “hard” outcomes occured (3 medic. flares, 4 resections and 1 new fistula) 2 in the PFR and 6 in the NR group (25% vs. 75%; p < 0.01). Correlation with clinical response is presented in Figure 2. Figure 1. Figure 2. Correlation clinical response - log EC50 changes: 1 No, 2 partial, 3 complete clinical response. Conclusion CD62L (L-Selectin) shedding is the first validated test of functional blockade of TNF alpha in anti-TNF treated IBD patients and will be a useful tool to guide medical decision on the use of anti-TNF agents. Comparative studies with ATI and trough level of IFX are ongoing. 1. Nicola Patuto, Emma Slack, Frank Seibold and Andrew J. Macpherson, (2011), Quantitating Anti-TNF Functionality to Inform Dosing and Choice of Therapy, Gastroenterology, 140 (5, Suppl. I), S689.

Standardised animal models of host microbial mutualism.

An appreciation of the importance of interactions between microbes and multicellular organisms is currently driving research in biology and biomedicine. Many human diseases involve interactions between the host and the microbiota, so investigating the mechanisms involved is important for human health. Although microbial ecology measurements capture considerable diversity of the communities between individuals, this diversity is highly problematic for reproducible experimental animal models that seek to establish the mechanistic basis for interactions within the overall host-microbial superorganism. Conflicting experimental results may be explained away through unknown differences in the microbiota composition between vivaria or between the microenvironment of different isolated cages. In this position paper, we propose standardised criteria for stabilised and defined experimental animal microbiotas to generate reproducible models of human disease that are suitable for systematic experimentation and are reproducible across different institutions.

An ambulance for retinol.

During inflammation, serum amyloid A proteins transport retinol to infected tissues.

Monitoring disease activity and progression in Crohn's disease. A Swiss perspective on the IBD ahead 'optimised monitoring' recommendations.

BACKGROUND AND AIMS The structured IBD Ahead 'Optimised Monitoring' programme was designed to obtain the opinion, insight and advice of gastroenterologists on optimising the monitoring of Crohn's disease activity in four settings: (1) assessment at diagnosis, (2) monitoring in symptomatic patients, (3) monitoring in asymptomatic patients, and (4) the postoperative follow-up. For each of these settings, four monitoring methods were discussed: (a) symptom assessment, (b) endoscopy, (c) laboratory markers, and (d) imaging. Based on literature search and expert opinion compiled during an international consensus meeting, recommendations were given to answer the question 'which diagnostic method, when, and how often'. The International IBD Ahead Expert Panel advised to tailor this guidance to the healthcare system and the special prerequisites of each country. The IBD Ahead Swiss National Steering Committee proposes best-practice recommendations adapted for Switzerland. METHODS The IBD Ahead Steering Committee identified key questions and provided the Swiss Expert Panel with a structured literature research. The expert panel agreed on a set of statements. During an international expert meeting the consolidated outcome of the national meetings was merged into final statements agreed by the participating International and National Steering Committee members - the IBD Ahead 'Optimized Monitoring' Consensus. RESULTS A systematic assessment of symptoms, endoscopy findings, and laboratory markers with special emphasis on faecal calprotectin is deemed necessary even in symptom-free patients. The choice of recommended imaging methods is adapted to the specific situation in Switzerland and highlights the importance of ultrasonography and magnetic resonance imaging besides endoscopy. CONCLUSION The recommendations stress the importance of monitoring disease activity on a regular basis and by objective parameters, such as faecal calprotectin and endoscopy with detailed documentation of findings. Physicians should not rely on symptoms only and adapt the monitoring schedule and choice of options to individual situations.

B cells as a critical node in the microbiota-host immune system network.

Mutualism with our intestinal microbiota is a prerequisite for healthy existence. This requires physical separation of the majority of the microbiota from the host (by secreted antimicrobials, mucus, and the intestinal epithelium) and active immune control of the low numbers of microbes that overcome these physical and chemical barriers, even in healthy individuals. In this review, we address how B-cell responses to members of the intestinal microbiota form a robust network with mucus, epithelial integrity, follicular helper T cells, innate immunity, and gut-associated lymphoid tissues to maintain host-microbiota mutualism.

Segmented filamentous bacterium uses secondary and tertiary lymphoid tissues to induce gut IgA and specific T helper 17 cell responses.

Segmented filamentous bacterium (SFB) is a symbiont that drives postnatal maturation of gut adaptive immune responses. In contrast to nonpathogenic E. coli, SFB stimulated vigorous development of Peyer's patches germinal centers but paradoxically induced only a low frequency of specific immunoglobulin A (IgA)-secreting cells with delayed accumulation of somatic mutations. Moreover, blocking Peyer's patch development abolished IgA responses to E. coli, but not to SFB. Indeed, SFB stimulated the postnatal development of isolated lymphoid follicles and tertiary lymphoid tissue, which substituted for Peyer's patches as inductive sites for intestinal IgA and SFB-specific T helper 17 (Th17) cell responses. Strikingly, in mice depleted of gut organized lymphoid tissue, SFB still induced a substantial but nonspecific intestinal Th17 cell response. These results demonstrate that SFB has the remarkable capacity to induce and stimulate multiple types of intestinal lymphoid tissues that cooperate to generate potent IgA and Th17 cell responses displaying only limited target specificity.