Characterization of Recombinant Human PRG4 as an Ocular Surface Boundary Lubricant

Introduction: Dry-eye disease involves tear film instability that can result in surface-to-surface contact between the cornea and eyelid or contact lens, where boundary lubrication can be dominant1. Motivated by the recent discovery that proteoglycan 4 (PRG4, a mucin-like glycoprotein originally discovered in synovial fluid as a boundary lubricant2), functions as an ocular surface boundary lubricant3, advances in recombinant protein expression technology4, and PRG4’s potential use as a friction-reducing contact lens coating, the objectives of this study were to: 1) biochemically characterize recombinant human PRG4 (rh- PRG4); and 2) assess the boundary lubricating properties of rh-PRG4, both before and after autoclave sterilization, at a cornea-contact lens material (PDMS) biointerface. Methods: SDS-PAGE western blot analysis using a variety of anti-PRG4 antibodies and lectins was performed on native PRG4 (nPRG4) and rh-PRG4 samples, both nonreduced and reduced, with and without enzymatic removal of O-linked glycosylations. Human corneas and PDMS were articulated against each other, subject to physiological loads of 8-25 kPa, at effective sliding velocities of 0.3-30 mm/s. Test lubricant sequences were A) saline, rh-PRG4 @300μg/mL, nPRG4 @300μg/mL, and saline; and B) saline, autoclaved rh-PRG4 @300μg/mL, rh-PRG4 @300μg/mL, and saline. Static and kinetic coefficients of friction were calculated. Results: rh-PRG4 demonstrated similar immunoreactivity to nPRG4, and effectively lowered friction at the cornea-PDMS biointerface. Western blotting indicated immunoreactive rh-PRG4 bands had a similar apparent molecular weight (MW) to nPRG4, and decreased appropriately upon reduction as well as enzymatic removal of glycosylations. Kinetic friction coefficients, which were highest in saline (0.31±0.06 to 0.40±0.06, mean±SEM), were similar in rh-PRG4 (0.12±0.01 to 0.25±0.03) and nPRG4 (0.19±0.02 to 0.28±0.03) across all velocities. Autoclaved rh-PRG4 had similar values to rh-PRG4 as well (0.19±0.02 to 0.26±0.04, 0.16±0.02 to 0.26±0.02, respectively). Conclusions: rh-PRG4 demonstrates similar biochemical and ocular surface lubricating properties to nPRG4, and may function as an effective friction-reducing contact lens coating

Faecalibacterium prausnitzii Strain HTF-F and Its Extracellular Polymeric Matrix Attenuate Clinical Parameters in DSS-Induced Colitis

Date of Acceptance: 26/02/2015 Funding: The authors received no specific funding for this work.Peer reviewedPublisher PD

Assessment of oesophageal emptying in achalasia patients by intraluminal impedance monitoring

Oesophageal emptying can be assessed by radiographic and scintigraphic tests with radiation exposure or by multichannel intraluminal impedance monitoring (MII). The aim of this study was to evaluate the applicability of MII for the assessment of oesophageal emptying in achalasia patients. In 10 achalasia patients, impedance tracings were scored independently by three observers after ingestion of a 100-mL barium bolus. Bolus clearance time (BCT) and height of barium column were scored using fluoroscopic images acquired at 20-s intervals. All patients showed a low baseline impedance level in the distal oesophagus. Air trapping in the proximal oesophagus was detected in nine patients. BCT on MII was similar to that on fluoroscopy in 40-70% of the patients. Correlations between height of barium on fluoroscopy and fluid level on MII were poor to moderate at different time intervals. Concordance (Kendall's coefficient) between the three observers for assessment of fluid level on MII was 0.31 (P = 0.04) at 1 and 5 min, 0.26 (P = 0.08) at 10 and 0.44 (P = 0.01) at 15 min. We conclude that in achalasia patients, low baseline impedance levels and air entrapment in the proximal oesophagus limit the value of intraluminal impedance monitoring as a test of oesophageal emptying

Top-down Infliximab Study in Kids with Crohn's disease (TISKids): an international multicentre randomised controlled trial

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Faecalibacterium prausnitzii A2-165 has a high capacity to induce IL-10 in human and murine dendritic cells and modulates T cell responses

Acknowledgements This work was financially supported by the EC FP7 Cross-talk project (PITN-GA-2008-215553). The authors thank the Histology Platform from GABI research unit and especially Abdelhak Boukadiri for their technical support in the histology sample preparation and Marlène Héry, Charline Pontlevoy, Jerome Pottier and André Tiffoche (UE0907 IERP, Jouy en Josas) for their help during animal experiments. The authors thank Rafael Muñoz-Tamayo (INRA) for his help in performing the PCA.Peer reviewedPublisher PD

Proteomic analyses do not reveal subclinical inflammation in fatigued patients with quiescent Inflammatory Bowel Disease

BackgroundFatigue is a common and clinically challenging symptom in patients with inflammatory bowel diseases (IBD). While fatigue occurs most often in patients with active disease, up to 50% of patients with quiescent disease still report significant fatigue of unknown aetiology. Here, we aimed to investigate whether fatigue in patients with quiescent IBD is reflected by circulating inflammatory proteins, that in turn might reflect ongoing subclinical inflammation.MethodsNinety-two (92) different inflammation-related proteins were measured in plasma of 350 patients with quiescent IBD (188 Crohn’s disease [CD]; 162 ulcerative colitis [UC]). Quiescent IBD was defined as clinical (Harvey-Bradshaw Index [HBI] <5 or Simple Clinical Colitis Activity Index [SCCAI] <2.5) and biochemical remission (C-reactive protein [CRP] <5 mg/L) at time of sampling. Fatigue severity was assessed on a visual analogue scale (VAS).ResultsNone of the analysed plasma proteins were differentially abundant between mildly (1st quartile, Q1) or severely (4th quartile, Q4) fatigued patients under a false discovery rate of 10%. Considering nominal significance (P<0.05), however, leukemia inhibitory factor receptor (LIF-R) concentrations were inversely associated with severe fatigue, also after adjustment for confounding factors (P <0.05) (Figure 1). Although solely LIF-R showed weak ability to discriminate between mild (Q1) and severe (Q4) fatigue (area under the curve [AUC]=0.61, 95% CI: 0.53–0.69, P<0.05), a combined set of the top seven (7) fatigue-associated proteins (LIF-R, vascular endothelial growth factor-A [VEGF-A], glial-derived neurotrophic factor [GDNF], interleukin-20 receptor subunit alpha [IL-20RA], Delta and Notch-like epidermal growth factor-related receptor [DNER], T-cell surface glycoprotein CD5 [CD5], and extracellular newly identified receptor for advanced glycation end-products binding protein [EN-RAGE], also known as protein S100-A12, all P<0.10) was observed to have reasonable discriminative performance (AUC=0.82 [95% CI: 0.74–0.91], P<0.01).ConclusionFatigue in patients with IBD is not clearly reflected by distinct circulating inflammatory protein signatures, which suggests that subclinical immune activation as defined by the studied panel of inflammatory proteins could not be detected. Reduced shedding of the LIF-R protein could be related to fatigue in IBD through modification of the oncostatin-M (OSM) signaling pathway, or through induction of pro-inflammatory phenotypes of T-cells, macrophages, or neural cells. Future studies are warranted to investigate other proteomic or metabolic markers that may accurately reflect fatigue in quiescent IBD, which might represent alternative pathophysiological pathways

International prospective observational study investigating the disease course and heterogeneity of paediatric-onset inflammatory bowel disease: the protocol of the PIBD-SETQuality inception cohort study

INTRODUCTION: Patients with paediatric-onset inflammatory bowel disease (PIBD) may develop a complicated disease course, including growth failure, bowel resection at young age and treatment-related adverse events, all of which can have significant and lasting effects on the patient's development and quality of life. Unfortunately, we are still not able to fully explain the heterogeneity between patients and their disease course and predict which patients will respond to certain therapies or are most at risk of developing a more complicated disease course. To investigate this, large prospective studies with long-term follow-up are needed. Currently, no such European or Asian international cohorts exist. In this international cohort, we aim to evaluate disease course and which patients are most at risk of therapy non-response or development of complicated disease based on patient and disease characteristics, immune pathology and environmental and socioeconomic factors. METHODS AND ANALYSIS: In this international prospective observational study, which is part of the PIBD Network for Safety, Efficacy, Treatment and Quality improvement of care (PIBD-SETQuality), children diagnosed with inflammatory bowel disease <18 years are included at diagnosis. The follow-up schedule is in line with standard PIBD care and is intended to continue up to 20 years. Patient and disease characteristics, as well as results of investigations, are collected at baseline and during follow-up. In addition, environmental factors are being assessed (eg, parent's smoking behaviour, dietary factors and antibiotic use). In specific centres with the ability to perform extensive immunological analyses, blood samples and intestinal biopsies are being collected and analysed (flow cytometry, plasma proteomics, mRNA expression and immunohistochemistry) in therapy-naïve patients and during follow-up. ETHICS AND DISSEMINATION: Medical ethical approval has been obtained prior to patient recruitment for all sites. The results will be disseminated through peer-reviewed scientific publications. TRIAL REGISTRATION NUMBER: NCT03571373

Yap1-Driven Intestinal Repair Is Controlled by Group 3 Innate Lymphoid Cells

Intestinal repair is driven by epithelial stem cells, but how these stem cells are instructed to initiate repair was unknown. Here, Romera-Hernández et al. report that epithelial proliferation after damage is independent of the stem cell-protective signal IL-22 but requires ILC3-dependent amplification of regenerative YAP1 signaling in stem cells.Tissue repair requires temporal control of progenitor cell proliferation and differentiation to replenish damaged cells. In response to acute insult, group 3 innate lymphoid cells (ILC3s) regulate intestinal stem cell maintenance and subsequent tissue repair. ILC3-derived IL-22 is important for stem cell protection, but the mechanisms of ILC3-driven tissue regeneration remain incompletely defined. Here we report that ILC3-driven epithelial proliferation and tissue regeneration are independent of IL-22. In contrast, ILC3s amplify the magnitude of Hippo-Yap1 signaling in intestinal crypt cells, ensuring adequate initiation of tissue repair and preventing excessive pathology. Mechanistically, ILC3-driven tissue repair is Stat3 indepe