The potential of virtual fencing technology to facilitate sustainable livestock grazing management

Virtual fencing (VF) technology is gaining interest due to its potential to facilitate sustainable grazing management. It allows farmers to contain grazing livestock without physical fences, thereby reducing the time and labour associated with the implementation of conventional fences. From a conservation perspective, some sensitive areas within uplands should not be grazed during certain periods of the year, and VF provides an invisible and moveable fence line that can exclude livestock from these areas. However, there are also concerns associated with its use, including animal welfare impacts, cost-effectiveness, and public perception. The extent to which VF can contribute to make livestock systems more sustainable remains to be investigated. To address this gap, this study investigates the potential of VF to promote sustainable grazing management using the Efficiency, Substitution, and Redesign framework, which has been used for the first time in this context. The framework is particularly relevant in taking an active and normative approach to identify key aspects to focus on to help achieve sustainability. We consulted stakeholders including farmers, wildlife inspectors, veterinarians, policy officers, researchers, NGOs, farm advisors or certification managers, through focus groups (N = 4) and in-depth, semi-structured interviews (N = 5). Stakeholders have highlighted the potential of VF to provide new opportunities to increase the efficiency and sustainability of livestock grazing systems, enabling their redesign, and contributing to improved environmental and animal welfare outcomes, as well as higher financial and social performance. However, there are important aspects that remain to be addressed to achieve such redesign, including issues of reliability due to poor network signal, animals' ability to learn, biosecurity and safety issues related to the absence of physical fences, farm suitability and farmers' ability to use the systems effectively. This study highlights the need to ensure that the development and uptake of VF are mutually beneficial to farmers, animals, and the wider farming industry. This includes a highlight on the importance of participative approaches to involve key stakeholders to address concerns and maximise the potential of the technology.

Estimating Model-Based Marginal Societal Health Benefits of Air Pollution Emission Reductions in the United States and Canada

We developed spatially detailed source-impact estimates of population health burden measures of air pollution for the United States and Canada by quantifying sources-receptor relationships using the benefit-per-ton (BPT1) metric. We calculated BPTs as the valuations of premature mortality counts due to fine particulate matter (PM2.5; particulate matter ≤2.5 μm in aerodynamic diameter) exposure resulting from emissions of one ton of a given pollutant. Our BPT estimates, while accounting for a large portion of societal impact, do not include morbidity, acute exposure mortality, or chronic exposure mortality due to exposure to other pollutants such as ozone.

The adjoint version of a widely used chemical transport model (CTM) allowed us to calculate location-specific BPTs at a high level of granularity for source-impact characterization. Location-specific BPTs provides a means for exploiting the disparities in source impact of emissions at different locations. For instance, estimated BPTs show that 20% of primary PM2.5 and ammonia emissions in the United States account for approximately 50% and 60% of the burden of each species, respectively, for an estimated burden of $370B USD. Similarly, 10% of the most harmful emissions of primary PM2.5 and ammonia emissions in Canada account for approximately 60% and 50% of their burden, respectively. By delineating differences and disparities in source impacts, adjoint-based BPT provides a direct means for prioritizing and targeting emissions that are most damaging.

Sensitivity analyses evaluated the impact of our assumptions and study design on the estimated BPTs. The choice of concentration-response function had a substantial impact on the estimated BPTs and is likely to constitute the largest source of uncertainty in those estimates. Our method for constructing annual BPT estimates based on episodic simulations introduces low uncertainty, while uncertainties associated with the spatial resolution of the CTM were evaluated to be of medium importance. Finally, while recognizing that the use of BPTs entails an implied assumption of linearity, we show that BPTs for primary PM2.5 emissions are stable across different emission levels in North America. While BPTs for precursors of secondary inorganic aerosols showed sensitivity to emission levels in the past, we found that those have stabilized with lower emissions and pollutant concentrations in the North American atmosphere.

We used BPTs to provide location-specific and sectoral estimates for the cobenefits of reducing carbon dioxide emissions from a range of combustion sources. Cobenefit estimates rely heavily on the emission characteristics of the sector and therefore exhibit more pronounced sectoral fingerprints than do BPTs. We provide cobenefit estimates for various subsectors of on-road transportation, thermal electricity generation, and off-road engines. Off-road engines and various heavy-duty diesel vehicles had the largest cobenefits, which in most urban locations far exceeded estimates of the social cost of carbon. Based on our cobenefit estimations, we also provide per-vehicle burden estimates for different vintages of vehicle subsectors such as transit buses and short-haul trucks in major US cities.

Cortical spheroid on perfusable microvascular network in a microfluidic device

Human induced pluripotent stem cell (hiPSC)-derived brain spheroids can recapitulate the complex cytoarchitecture of the brain, as well as the genetic/epigenetic footprint of human brain development. However, hiPSC-derived 3D models such as spheroid and organoids does not have a perfusable microvascular network, which plays a vital role in maintaining homeostasis in vivo. With the critical balance of positive and negative angiogenic modulators, 3D microvascular network can be achieved by angiogenesis. This paper reports on a microfluidic-based three-dimensional, cortical spheroid grafted on the vascular-network. Vascular network was formed by inducing angiogenic sprouting using concentration gradient-driven angiogenic factors in the microfluidic device. We investigate critical factors for angiogenic vascular network formation with spheroid placement, including 1) a PKCα activator, phorbol-12-myristate-13-acetate (PMA); 2) orientation of endothelial cells under perfusion and permeability of vascular network; 3) effect of extracellular matrix (ECM) types and their densities on angiogenesis; and 4) integration with cortical spheroid on vascular network. This paper demonstrates proof of concept for the potential utility of a membrane-free in vitro cortical spheroid tissue construct with perfusable microvascular network that can be scaled up to a high throughput platform. It can provide a cost-effective alternative platform to animal testing by modeling brain diseases and disorders, and screening drugs.

A shared accretion instability for black holes and neutron stars

Accretion disks around compact objects are expected to enter an unstable phase at high luminosity1. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion and refilling of the inner disk on short timescales2. Such a scenario, however, has only been quantitatively verified for a single stellar-mass black hole3-5. Although there are hints of these cycles in a few isolated cases6-10, their apparent absence in the variable emission of most bright accreting neutron stars and black holes has been a continuing puzzle11. Here we report the presence of the same multiwavelength instability around an accreting neutron star. Moreover, we show that the variability across the electromagnetic spectrum-from radio to X-ray-of both black holes and neutron stars at high accretion rates can be explained consistently if the accretion disks are unstable, producing relativistic ejections during transitions that deplete or refill the inner disk. Such a new association allows us to identify the main physical components responsible for the fast multiwavelength variability of highly accreting compact objects.

"Much better than I thought it was going to be": Telehealth delivered group-based education and exercise was perceived as acceptable among people with knee osteoarthritis

Objective

To understand patient perceived acceptability of participating in a telehealth delivered group-based education and exercise-therapy program for knee osteoarthritis.

Design

This qualitative study involved semi-structured, one-on-one interviews with knee osteoarthritis patients who have completed the Good Living with osteoArthritis from Denmark (GLA:D®) program via telehealth or in-person. Interviews were recorded, transcribed verbatim, coded, and analysed using an inductive content analysis approach, focusing on themes related to telehealth.

Results

Nineteen participants [12 (63%) female, mean aged 62 years, range 49-72 years] were included. Eleven (58%) received GLA:D® via telehealth and 8 (42%) attended in-person sessions. Two overarching themes (6 sub-themes) related to telehealth perceived acceptability were identified: 1) Perceptions of telehealth acceptability was highly influenced by exposure. Individuals who had received telehealth considered it easy, convenient, and flexible, whereas telehealth was perceived to be inferior and misunderstood by those without exposure. 2) Telehealth participants reported similar program benefits to in-person participants, including reduced fear of pain and joint damage, changed beliefs in value of exercise, and stated improvements in pain and function.

Conclusions

Telehealth delivery of group-based education and exercise-therapy for knee osteoarthritis was acceptable for people who had experienced it and provides similar benefits as in-person care for pain and beliefs about the safety and value of exercise. Wider implementation of telehealth group-based education and exercise-therapy may improve access to high value care for people with knee osteoarthritis.

A Three-Dimensional Brain-on-a-Chip Using Human iPSC-Derived GABAergic Neurons and Astrocytes

Brain-on-a-chip is a miniaturized engineering platform to mimic the structural and functional aspects of brain tissue. We describe a method to construct a three-dimensional (3D) brain-on-a-chip in this chapter. We firstly portray the method of a brain-on-a-chip model with cocultured mice neurons, microglia, and astrocytes to mimic brain tissue and membrane-free perfusion with endothelial cells, in which we successfully build the blood-brain barrier to screen neurotoxicity. Then we describe a method to construct a brain-on-a-chip with human induced pluripotent stem cell (iPSC)-derived neurons and astrocytes to simulate human brain behavior. This platform consists of neuronal tissue with extracellular matrix (ECM)-embedded GABAergic neurons and astrocytes and a perfusion channel with dynamic flow. We also include the broader applicability test of this model using an organophosphate (OP), malathion, to induce acute and chronic neurotoxicity, and then using butyrylcholinesterase (BuChE) as an exogenous bioscavenger of OP. Following the methods listed in this chapter, we are able to measure the neurotoxic effects on construct integrity, viability, and total AChE and BuChE activity.

46 Primary Care Practitioners Have A High Level of Satisfaction with The Current Breast Referral Pathway but The Majority Would Support A Change to Patient Self-Referral

Aim

Currently, patients must consult with a primary care practitioner (PCP) prior to being referred to secondary care breast services. A change to patient self-referral would arguably reduce primary care workload, improve access for patients, and allow breast units to allocate resources more appropriately; no data currently supports this. This study aims to explore PCP's views on breast referral, evaluate the community breast workload, and to investigate the impact of COVID-19 on referral rates.

Method

An electronic survey was designed on SurveyMonkey.com which aimed to collect both quantitative and qualitative data. The weblink to the survey was sent out via two electronic newsletters. Participants were asked: their role and gender, their level of confidence surrounding breast care, details surrounding their breast workload, how they felt COVID-19 had affected their referral rates, their level of satisfaction with the current pathway, and their opinions on a potential change to patient self-referral.

Results

79 responses were received. PCPs estimated that 7.0% (median) of their total consultations were regarding a breast-related issue and that COVID-19 had not had a significant impact on the rate of referral to breast units (P = 0.75). 84.8% of PCPs were satisfied with the current referral pathway. Whilst 74.5% felt a change to patient self-referral would benefit patients and primary care services, their free text comments highlighted some of their reservations.

Conclusions

PCPs have a high level of satisfaction with the current breast referral pathway, but the majority would be open to a change to patient self-referral to specialist breast units.

296 Case Report: Pacemaker Lead-Induced Fibrosis Resulting in Right Atrial and Tricuspid Stenosis Managed with An Open Surgical Approach

Pacemaker leads can result in localised inflammation and, over time, fibrosis. Rarely, this can significantly alter the anatomy of the heart and impair cardiac function. In this case, a fifty-year-old female had undergone pacemaker placement in her teens having experienced symptomatic bradycardia. Due to pacemaker pocket erosion, she had undergone a lead extraction where lead fragments had been left in-situ. Years after a new generator and leads were placed, she presented with symptoms of proximal venous congestion and superior vena cava (SVC) syndrome. A venogram demonstrated completely occluded brachiocephalic and innominate veins with significant adjacent venous collateralization. Computed tomography showed partial obstruction of the SVC and tricuspid stenosis. Initially, a decision was made not to intervene.

After developing abdominal distension, she was diagnosed with hepatic congestion and cirrhosis secondary to elevated right sided pressures and right atrial congestion due to tricuspid stenosis. It was concluded that the patient’s symptoms were the result of occluded proximal veins, SVC syndrome, and functional tricuspid stenosis, all of which were likely the result of fibrotic tissue secondary to pacemaker lead-induced inflammation. Due to the severity of her symptoms, the patient accepted the risks associated with surgical management. Intra-operatively, electrocautery was used to debride the fibrotic tissue inhibiting the leaflets of the tricuspid valve. This worked to great effect and additional valve repair/replacement was not necessary. Whilst the patient has been left with SVC syndrome, her tricuspid stenosis symptoms are greatly improved. To our knowledge, such a case has not been previously described.

48 Chyle Leak Following Pancreaticoduodenectomy: A Tertiary HPB Unit 14-year Experience and a Proposed Management Algorithm

Introduction

Chyle leak (CL) is an uncommon complication of pancreaticoduodenectomy (PD). Its incidence, risk factors, and effect on prognosis are not well described and optimum management remains debated. This study aims to calculate the incidence of CL, identify risk factors, consider effect on patient outcome, and propose a simple management algorithm.

Method

This is a retrospective review of all patients who developed CL following PD between January 2006 and April 2020. The following details were obtained from a prospectively maintained database: age, ASA grade, BMI, details of operation, tumour histology, length of stay, and mortality.

Results

A total of 560 patients underwent PD and 17 (3.04%) developed CL. These patients had significantly higher BMI (P < 0.01) and significantly longer operation times (P < 0.05). CL patients had a higher rate of portal vein (PV) tumour adherence, PV resection, and intra-operative blood transfusion although this was not statistically significant. Sixteen CL patients (94.1%) were managed successfully with a non-operative approach.

Conclusions

3.04% of patients who underwent PD developed CL. CL was associated with higher BMI and longer operation time. CL did not affect length of stay. The vast majority of CL cases can be managed successfully with a non-operative approach.

A survey analysis of farmer practices and perceptions of zero-grazing on Irish dairy farms

Zero-grazing (ZG; the mechanical harvesting and feeding of fresh grass) is increasingly used in grass-based milk production systems alongside conventional grazing. It allows farmers to supply fresh grass from land parcels that are outside of the main grazing block during seasonal shortages and periods when climatic conditions limit animal grazing opportunities. The objective of this study was to establish an understanding of current ZG practices on Irish dairy farms, to capture farmer perceptions on the implementation of this management practice, and to identify farmer knowledge requirements on ZG. An online survey was distributed and completed by 130 dairy farmers who use or have used ZG. Zero-grazing was used alongside conventional grazing by 92% of respondents. These farms were particularly fragmented, with between 1 and 14 separate land blocks. Respondents felt ZG helped them overcome fragmentation, increase grass use, and extend grass feeding in spring and autumn. However, extra cost and time input associated with ZG were recognized as key challenges. The majority of respondents rated current technical information available on ZG in the Republic of Ireland as "poor" or "very poor," and knowledge deficits were identified in the areas of cost analysis, grass management and productivity, cow productivity, cow health and nutrition, and soil fertility.

SAT0356 THE ROLE OF IL-36 AS A POTENTIAL NOVEL THERAPEUTIC TARGET IN SPONDYLARTHROPATHY ASSOCIATED PATHOLOGY DUE TO ITS UPSTREAM INDUCTION OF IL-23/IL-17 PATHWAY CYTOKINES AND STROMAL ACTIVATION IN AN IN VITRO ENTHESITIS MODEL

Background:

Enthesitis, defined as inflammation of anchorage points of tendons, ligaments and joint capsules to bones, is now understood to be the cardinal pathogenic lesion in spondyloarhtopathies (SpA). Evidence from genetic studies, animal models, and therapeutic studies firmly implicates the IL-23/IL-17 axis in the pathogenesis of SpA. We have recently confirmed the presence of IL-23 myeloid cells and IL-17 producing T cells populations in the human enthesis (McGonagle, ARD 2019). The upstream drivers of these key cytokines in the enthesis is, however, not defined. Emerging evidence suggests that IL-36 may be critical in regulating the IL-23/IL-17 axis in various organs. Also IL-38 SNPs have been associated with SpA which is of interest given that IL-38 is an IL-36 antagonist. Further, IL-36α is upregulated in the joints of psoriatic arthritis patients and deficiency of the IL-36 receptor antagonist (DITRA) results in generalized pustular psoriasis with comorbid arthritis in at least third of patients. Thus, we hypothesised that IL-36 could be an upstream regulator of the IL23/17 axis at the enthesis.

Objectives:

To confirm the induction of IL-36 at the human enthesis and to test the effect of IL-36 on resident innate and adaptive immune cell populations and enthesis stromal cells.

Methods:

Entheseal spinous processes from patients undergoing elective orthopaedic surgeries was obtained and mechanically digested. Peri-entheseal bone (PEB), and entheseal soft tissue (EST) digests were stimulated with fungal and bacterial adjuvants and IL-36 measured by ELISA. Disease relevant compounds such as methotrexate and PDE4i were assessed for their ability to attenuate IL-36 secretion. IHC was used to confirm the presence of IL-36R+ cells in the enthesis. Digested PEB was stimulated with IL-36, and IL-6, IL-8, IL-23, and TNF-alpha were analysed by ELISA and Flow Cytometry. As the IL-36 cytokines require protease mediated post translational processing for full activation, these were measured in enthesis digests. Entheseal fibroblasts were isolated and stimulated with IL-36 and ICAM-1 measured by Flow Cytometry and genes by qPCR.

Results:

TLR ligands induced the production of IL-36 at the enthesis. Further cell sorting, revealed CD11+ myeloid cells were the predominant entheseal producer of IL-36. Induced IL-36 could be significantly attenuated by PDE4i but not by methotrexate. IHC confirmed the presence of IL-36R+ in the enthesis. Stimulation of enthesis digest with IL-36 significantly upregulated the production of IL-6, IL-8, TNF-a, and IL-23. Stimulation of enthesis fibroblasts with IL-36 upregulated surface ICAM-1 and secretion of IL-6, CCL2 and CCL20. Enthesis digests showed high basal expression of IL-36 activating protease including cathepsin S and G.

Conclusion:

IL-36 is inducible from enthesis myeloid cells and IL-36R+ cells are present at the enthesis. Enthesis stimulation with IL-36 results in the upregulation of several disease relevant mediators such as TNF, IL-23 and CCL20 in both immune and stromal lineage cells. This is the first demonstration of IL-36 production in human enthesis. Given its pleiotropic effect and relation to IL-23/IL-17 axis, IL-36 is a potential novel therapeutic target in SpA.

Figure 1.

Expression and role of IL-36 at the enthesis. (A). IL-36 is induced by stimulation with lipopolysaccharide (LPS) and Mannan. (B) IL-36 is predominantly produced by CD11c+ cells. (C) IL-36 stimulation of PEB resulted in increased TNF-alpha production by CD14+ cells, and increased production of IL-23 (D) IL-36 stimulation of stromal cells increased ICAM-1 expression, and CCL2, CCL20, IL-6 and IL8 secretion

Figure 2.

Gene expression by qPCR following stromal cell stimulation by IL-36

Disclosure of Interests:

Kassem Sharif: None declared, Charlie Bridgewood: None declared, Tobias Russell Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Hannah Rowe Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Qaio Zhou: None declared, Abhay S Rao: None declared, Almas Khan: None declared, Robert Dunsmuir: None declared, Dennis McGonagle Grant/research support from: Janssen Research & Development, LLC

THU0028 AN EXPLANTION FOR HOW VIRAL INFECTION MAY TRIGGER SPONDYLOARTHROPATHY BASED ON TLR9 DRIVEN TNF RESPONSES FROM ENTHESEAL DERIVED PLASMACYTOID DENDRITIC CELLS

Background:

It is well known that viral infections may trigger psoriatic arthritis (PsA), a disease that typically has extensive pre-clinical entheseal abnormalites. Skin resident plasmacytoid dendritic cells (pDCs) produce IFNα that contribute to T cell expansion and the development of experimental psoriasis [1, 2]. IFN pathway SNPs have been reported in both PsA and psoriasis and we previously reported the presence of pDCs at the human enthesis [3].

Objectives:

To investigate whether the TLR9 agonist ODN that replicates viral infection activate a wide array of of entheseal derived pDCs molecular cascades including the TNF pathway that might provide a link between viral infection and PsA.

Methods:

pDCs were sorted from enthesis and blood and stimulated with ODN as previously described (n=16) [3, 4]. IFNα protein pre and post stimulation were detected by ELISA. Intracellular flow cytometry (IFC) of entheseal pDCs was used to detect TNF protein. RNA was extracted post-stimulation. The mRNA were hybridised and tagged by probes then measured on the nCounter platform. Data was analysed using nSolver 4.0. Log2 |fold change| >1 and P-value <0.05 were considered statistically significant. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) of differentially expressed genes (DEGs) were analyzed using DAVID. Protein-protein interaction (PPI) network was drawn by STRING.

Results:

Stimulated entheseal pDCs showed a strong DEGs pattern pointing towards increased TNF expression. There were 11 genes significantly upregulated including TNF. RIPK3 is involved in TNF signalling pathway. TNF, RIPK3 and ZBP1 are involved in necroptosis. TNF and ITGB2 are involved in IL-4 and IL-13 signaling pathway. TNF, HLA-DOA, ITGB2/TLR7 are involved in virus infection. Together it highlights extremely activated TNF pathway genes.

IFN protein was induced in sorted entheseal pDCs following stimulation (n=8). TNF protein was detected by IFC on stimulated entheseal pDCs (CD45+HLA-DR+CD123+CD303+ CD11c-) (n=3). We also compared entheseal and matched peripheral blood pDCs (n=8) following stimulation where no major differences in the TNF pathway were present between groups.

The KEGG analysis was mapped in Figure 1. GO analysis showed the most significant change in biological processes was enriched in the positive regulation of DNA binding transcription factor activity. The change in molecular function was mainly enriched in p53 binding.

Conclusion:

Entheseal pDCs, upon viral molecule stimulation, show several markers of activation. However, TNF pathway genes were highly activiated which provides a novel mechanistic link between viral infection and PsA as reported in epidemiological studies.

References:

[1]Nestle, F.O., et al.,Plasmacytoid predendritic cells initiate psoriasis through interferon-alpha production.J Exp Med, 2005.202(1): p. 135-43.

[2]Christophers, E., et al.,The risk of psoriatic arthritis remains constant following initial diagnosis of psoriasis among patients seen in European dermatology clinics.J Eur Acad Dermatol Venereol, 2010.24(5): p. 548-54.

[3]Zhou, Q.,PLASMACYTOID DENDRITIC CELLS IN THE ENTHESIS: PHENOTYPING AND FUNCTION INVESTIGATION.Annals of the Rheumatic Diseases, 2019.78.

[4]Bridgewood, C., et al.,Identification of myeloid cells in the human enthesis as the main source of local IL-23 production.Ann Rheum Dis, 2019.78(7): p. 929-933.

Disclosure of Interests:

Qiao Zhou: None declared, Jayakumar Vadakekolathu: None declared, Kassem Sharif: None declared, Tobias Russell Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Hannah Rowe Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Peter Millner: None declared, Peter Loughenbury: None declared, Abhay S Rao: None declared, Robert Dunsmuir: None declared, Charlie Bridgewood: None declared, Yasser El-Sherbiny: None declared, Dennis McGonagle Grant/research support from: Janssen Research & Development, LLC

SAT0358 A ROLE FOR IL-4 AND IL-13 IN MODULATING THE IL-23/IL-17 AXIS IN ENTHESITIS

Background:

IL-4 and IL-13 are related Th2 cytokines, with documented roles in allergic inflammation such as atopic dermatitis (AD). Psoriatic Arthritis (PsA) is typically thought to be a result of Th1/Th17 driven response, and blockage of this pathway (IL-23, IL-17 and TNF) has proven successful. Despite this, there is a strong genetic risk association for IL-13 and PsA(1), however, the precise role of IL-13 in PsA is presently unknown. The enthesis is the region where tendons or ligaments attach to bone, and inflammation of this site (enthesitis) is thought to be the cardinal lesion of PsA, whereas as Rheumatoid Arthritis inflammation is more synovial centric. Dupilumab is a monoclonal antibody that works by blocking the common receptor chain (IL-4α) shared by both IL-13 and IL-4. Recent studies have reported that AD patients receiving dupilumab have developed clinical enthesitis(2).

Objectives:

To investigate whether IL-4 and IL-13 could modulate IL-23production from entheseal myeloid cells and IL-17 production from enthseal T-cells.

Methods:

Healthy enthesis samples from patients undergoing surgery for non-inflammatory conditions such a lumbar decompression or scoliosis were obtained. Enthesis samples were digested and stimulated (Fig 1A) with LPS and anti-CD3 to induce IL-23 and IL-17 respectively. Samples were pre-treated with IL-4 and IL-13 to ascertain whether this modulated entheseal cytokine production.

Results:

Both IL-23 and IL-17 were readily induced from enthesis samples with IL-23 coming predominantly from entheseal myeloid resident cells (Fig 1B) and IL-17A from T-cells (Fig 1C). Pre-treatment of entheseal digested material with either IL-4 or IL-13 attenuated IL-23 secretion (Fig 1D). Neither IL-4 nor IL-13 was able to significantly attenuate IL-17 secretion from enthesis T-cells, however IL-13 trended downwards and IL-4 surprisingly trended upwards (Fig 1E).

Conclusion:

Our clinical and vitro data point towards a previously unknown role for IL-4 and IL-13 having a protective role in entheseal induction of IL23/17 axis cytokines. These findings point towards a novel explanation for IL-13 pathway SNPs in PsA and also a molecular explanation for why anti-IL4/13 therapy may induce entheseal pathology.

References:

[1]BOWES, J., S. EYRE, E. FLYNN, P. HO, S. SALAH, R.B. WARREN, H. MARZO-ORTEGA, L. COATES, R. MCMANUS, A.W. RYAN, D. KANE, E. KORENDOWYCH, N. MCHUGH, O. FITZGERALD, J. PACKHAM, A.W. MORGAN, C.E. GRIFFITHS, I.N. BRUCE, J. WORTHINGTON and A. BARTON. Evidence to support IL-13 as a risk locus for psoriatic arthritis but not psoriasis vulgaris.Ann Rheum Dis, 2011,70(6), pp.1016-9.

[2]WILLSMORE, Z.N., R.T. WOOLF, C. HUGHES, B. MENON, B. KIRKHAM, C. SMITH and A. PINK. Development of inflammatory arthritis and enthesitis in patients on dupilumab: a case series.British Journal of Dermatology, 2019,181(5), pp.1068-1070.

Disclosure of Interests:

Charlie Bridgewood: None declared, Kassem Sharif: None declared, Hannah Rowe Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Tobias Russell Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Dennis McGonagle Grant/research support from: Janssen Research & Development, LLC

SAT0361 HEALTHY HUMAN SPINAL PROCESSES PERI-ENTHESEAL T-CELLS EXHIBIT A TR1 RATHER THAN A FOXP3 REGULATORY PHENOTYPE

Background:

We have previously reported that the normal spinal enthesis has populations of conventional T-cells including CD4+ & CD8+ T-cells that could be induced to produce IL-17A and TNF following anti-CD3/CD28 stimulation. The biology of such cells in health including their normal function and antigen reactivity is completely unknown. The purpose of this work was to define the phenotype, functionality and TCR reactivity of such T-cells in health.

Objectives:

To investigate whether the T-cells at the normal enthesis were regulatory in nature and to determine the type of regulatory T-cell as Tr1 or FOXP3 regulatory T-cell and to determine T-cell reactivity.

Methods:

Healthy interspinous ligament and spinous process with matched peripheral blood were harvested from patients undergoing elective spinal surgery (n=20). Entheseal soft tissue (EST) & peri-entheseal bone (PEB) was enzymatically digested and then sorted. Tr1 and Treg phenotypes were investigated using flow cytometry. Analysis of cytokines, growth factors and chemokines was performed by qRT-PCR, ELISA and flow cytometry. TCR sequencing was performed and a search for putative T-cell reactivity was done using TCR3 database.

Results:

Pro-inflammatory cytokine transcripts including IL-17A, IL-17F, IL-22, IL-23 (p19) & TNF were very low or undetectable in the Enthesis T-cells (Fig 1). Flow cytometry confirmed entheseal T-cells had a Tr1 phenotype (CD4+ LAG3+ CD49b+). Intracellular flow cytometry showed enthesis T-cells had very low FOXP3 expression, when compared to their blood counterparts. Intracellular flow cytometry and gene expression showed high basal expression of growth factors and regulatory proteins such as IL-10 & TGFβ, when compared to blood T-cells. RNA-Seq data, showed 13 potential TCR clonal sequences the most common of which are predicted to be reactive viral infection was CMV present in 8 sequences and Influenza A virus present in 2 sequences.

Conclusion:

The healthy human enthesis has regulatory T-cells of a Tr1 phenotype rather than a FOXP3 Treg phenotype. Many clones have antigen specificity indicating reactivity to prior infection. These findings suggest that conventional entheseal T-cells have a role in enthesis immune homeostasis.

Disclosure of Interests:

Hannah Rowe Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Abdulla Watad: None declared, Tobias Russell Grant/research support from: Novartis UK Investigator Initiated non-clinical research funding support, Kassem Sharif: None declared, Darren Newton: None declared, Miriam Wittmann: None declared, Qiao Zhou Grant/research support from: Funded by the PARTNER fellowship program, Almas Khan: None declared, Peter Loughenbury: None declared, Robert Dunsmuir: None declared, Abhay S Rao: None declared, Peter Millner: None declared, Tony Kenna: None declared, Matthew Brown: None declared, Charlie Bridgewood: None declared, Dennis McGonagle Grant/research support from: Janssen Research & Development, LLC

Three-dimensional brain-on-chip model using human iPSC-derived GABAergic neurons and astrocytes: Butyrylcholinesterase post-treatment for acute malathion exposure

Organophosphates (OPs) induce acute and chronic neurotoxicity, primarily by inhibiting acetylcholinesterase (AChE) activity as well as by necrosis, and apoptosis. Butyrylcholinesterase (BuChE), an exogenous bioscavenger of OPs, can be used as a treatment for OP exposure. It is prerequisite to develop in vitro brain models that can study BuChE post-treatment for acute OP exposure. In this study, we developed a three-dimensional (3D) brain-on-chip platform with human induced pluripotent stem cell (iPSC)-derived neurons and astrocytes to simulate human brain behavior. The platform consists of two compartments: 1) a hydrogel embedded with human iPSC-derived GABAergic neurons and astrocytes and 2) a perfusion channel with dynamic medium flow. The brain tissue constructs were exposed to Malathion (MT) at various concentrations and then treated with BuChE after 20 minutes of MT exposure. Results show that the iPSC-derived neurons and astrocytes directly interacted and formed synapses in the 3D matrix, and that treatment with BuChE improved viability after MT exposure up to a concentration of 10⁻³ M. We conclude that the 3D brain-on-chip platform with human iPSC-derived brain cells is a suitable model to study the neurotoxicity of OP exposure and evaluate therapeutic compounds for treatment.

Three-dimensional (3D) brain microphysiological system for organophosphates and neurochemical agent toxicity screening

We investigated a potential use of a 3D tetraculture brain microphysiological system (BMPS) for neurotoxic chemical agent screening. This platform consists of neuronal tissue with extracellular matrix (ECM)-embedded neuroblastoma cells, microglia, and astrocytes, and vascular tissue with dynamic flow and membrane-free culture of the endothelial layer. We tested the broader applicability of this model, focusing on organophosphates (OPs) Malathion (MT), Parathion (PT), and Chlorpyrifos (CPF), and chemicals that interact with GABA and/or opioid receptor systems, including Muscimol (MUS), Dextromethorphan (DXM), and Ethanol (EtOH). We validated the BMPS platform by measuring the neurotoxic effects on barrier integrity, acetylcholinesterase (AChE) inhibition, viability, and residual OP concentration. The results show that OPs penetrated the model blood brain barrier (BBB) and inhibited AChE activity. DXM, MUS, and EtOH also penetrated the BBB and induced moderate toxicity. The results correlate well with available in vivo data. In addition, simulation results from an in silico physiologically-based pharmacokinetic/pharmacodynamic (PBPK/PD) model that we generated show good agreement with in vivo and in vitro data. In conclusion, this paper demonstrates the potential utility of a membrane-free tetraculture BMPS that can recapitulate brain complexity as a cost-effective alternative to animal models.

Telerehabilitation is non-inferior to usual care following total hip replacement - a randomized controlled non-inferiority trial

OBJECTIVES

Determine if outpatient physiotherapy care via telerehabilitation is as effective as in-person physiotherapy care after total hip replacement.

DESIGN

Randomised, single-blind, controlled, non-inferiority clinical trial.

SETTING

QEII Jubilee Hospital, Brisbane, Australia.

PARTICIPANTS

Seventy patients receiving a total hip replacement entered the study, sixty-nine completed the study.

INTERVENTIONS

The control group (n=35; x¯ age 67; female 60%) received in-person outpatient physiotherapy and a paper-based home exercise programme. The intervention group (n=35; x¯ age 62; female 66%) received remotely delivered telerehabilitation directly into their homes and a technology-based home exercise program using an iPad application.

MAIN OUTCOME MEASURES

The primary outcome was the quality of life subscale of the Hip disability and Osteoarthritis Outcome Score measured at six weeks post-operatively. Secondary outcomes included objective strength and balance outcomes, self-reported function and satisfaction outcomes, and home exercise program compliance.

RESULTS

No between group difference was detected in the Hip disability and Osteoarthritis Outcome Score quality of life subscale at the primary end point of six weeks (P=0.970). Strength, balance and self-reported function showed no between group differences. Overall satisfaction was high across both groups, with the intervention group scoring higher for ease of attending appointments (intervention 95 (10), control 86 (18), mean difference 9 (95% CI 2 to 16), P=0.017. The intervention group were more compliant with their home exercise programme (intervention 86% (20%), control 74% (26%), mean difference 12% (95% CI 1% to 23%), P=0.048).

CONCLUSIONS

Telerehabilitation programmes can be delivered to total hip replacement patients in their own homes, using readily available technology while maintaining high levels of satisfaction. More importantly, telerehabilitation patients appear to achieve non-inferior physical and functional outcomes as those receiving in-person rehabilitation programmes.

TRIAL REGISTRATION

ACTRN12615000824561. (Australian New Zealand Clinical Trials Registry).

Comparison of endothelial cell attachment on surfaces of biodegradable polymer-coated magnesium alloys in a microfluidic environment

Polymeric coatings can provide temporary stability to bioresorbable metallic stents at the initial stage of deployment by alleviating rapid degradation and providing better interaction with surrounding vasculature. To understand this interfacing biocompatibility, this study explored the endothelial-cytocompatibility of polymer-coated magnesium (Mg) alloys under static and dynamic conditions compared to that of non-coated Mg alloy surfaces. Poly (carbonate urethane) urea (PCUU) and poly (lactic-co-glycolic acid) (PLGA) were coated on Mg alloys (WE43, AZ31, ZWEKL, ZWEKC) and 316L stainless steel (316L SS, control sample), which were embedded into a microfluidic device to simulate a vascular environment with dynamic flow. The results from attachment and viability tests showed that more cells were attached on the polymer-coated Mg alloys than on non-coated Mg alloys in both static and dynamic conditions. In particular, the attachment and viability on PCUU-coated surfaces were significantly higher than that of PLGA-coated surfaces of WE43 and ZWEKC in both static and dynamic conditions, and of AZ31 in dynamic conditions (P<0.05). The elementary distribution map showed that there were relatively higher Carbon weight percentages and lower Mg weight percentages on PCUU-coated alloys than PLGA-coated alloys. Various levels of pittings were observed underneath the polymer coatings, and the pittings were more severe on the surface of Mg alloys that corroded rapidly. Polymer coatings are recommended to be applied on Mg alloys with relatively low corrosion rates, or after pre-stabilizing the substrate. PCUU-coating has more selective potential to enhance the biocompatibility and mitigate the endothelium damage of Mg alloy stenting.

Training physiotherapy students to educate patients: A randomised controlled trial

OBJECTIVE

To determine the effect of a training intervention on physiotherapy students' self-efficacy and skills in the area of patient education.

METHODS

Final year physiotherapy students were randomised to an intervention group or a wait-list control group. The intervention group participated in a 3.5h training intervention about patient education that included video observation, simulated patient practice and structured feedback. The control group did not receive any training. Self-efficacy was assessed at baseline (T1) and after the intervention (or no intervention for the control group) (T2). Patient education performance was assessed by a blinded rater from a video-recorded standardised clinical examination.

RESULTS

83 students were randomised to the intervention group and 81 students to the control group. There were no differences in demographic variables or self-efficacy between groups at baseline. There was significant improvement in self-efficacy for the intervention group, but no change for the control group. The intervention group performed significantly better than the control group for nine of the eleven performance items, with significantly higher scores overall.

CONCLUSION

A training intervention enhances physiotherapy student self-efficacy and performance in patient education.

PRACTICE IMPLICATION

Use of patient education training is recommended to enhance student self-efficacy and performance.