Gut complement induced by the microbiota combats pathogens and spares commensals.

Canonically, the complement system is known for its rapid response to remove microbes in the bloodstream. However, relatively little is known about a functioning complement system on intestinal mucosal surfaces. Herein, we report the local synthesis of complement component 3 (C3) in the gut, primarily by stromal cells. C3 is expressed upon commensal colonization and is regulated by the composition of the microbiota in healthy humans and mice, leading to an individual host's specific luminal C3 levels. The absence of membrane attack complex (MAC) components in the gut ensures that C3 deposition does not result in the lysis of commensals. Pathogen infection triggers the immune system to recruit neutrophils to the infection site for pathogen clearance. Basal C3 levels directly correlate with protection against enteric infection. Our study reveals the gut complement system as an innate immune mechanism acting as a vigilant sentinel that combats pathogens and spares commensals.

Plasticity and genetic effects contribute to different axes of neural divergence in a community of mimetic Heliconius butterflies.

Changes in ecological preference, often driven by spatial and temporal variation in resource distribution, can expose populations to environments with divergent information content. This can lead to adaptive changes in the degree to which individuals invest in sensory systems and downstream processes, to optimize behavioural performance in different contexts. At the same time, environmental conditions can produce plastic responses in nervous system development and maturation, providing an alternative route to integrating neural and ecological variation. Here, we explore how these two processes play out across a community of Heliconius butterflies. Heliconius communities exhibit multiple Mullerian mimicry rings, associated with habitat partitioning across environmental gradients. These environmental differences have previously been linked to heritable divergence in brain morphology in parapatric species pairs. They also exhibit a unique dietary adaptation, known as pollen feeding, that relies heavily on learning foraging routes, or trap-lines, between resources, which implies an important environmental influence on behavioural development. By comparing brain morphology across 133 wild-caught and insectary-reared individuals from seven Heliconius species, we find strong evidence for interspecific variation in patterns of neural investment. These largely fall into two distinct patterns of variation; first, we find consistent patterns of divergence in the size of visual brain components across both wild and insectary-reared individuals, suggesting genetically encoded divergence in the visual pathway. Second, we find interspecific differences in mushroom body size, a central component of learning and memory systems, but only among wild caught individuals. The lack of this effect in common-garden individuals suggests an extensive role for developmental plasticity in interspecific variation in the wild. Finally, we illustrate the impact of relatively small-scale spatial effects on mushroom body plasticity by performing experiments altering the cage size and structure experienced by individual H. hecale. Our data provide a comprehensive survey of community level variation in brain structure, and demonstrate that genetic effects and developmental plasticity contribute to different axes of interspecific neural variation.

Training the trainers: improving the quality of education delivered to paramedics through a simulation-debrief model.

Introduction: Education and training delivered within ambulance services is vital to clinicians maintaining competence, confidence and currency. Simulation and debrief in medical education aims to imitate clinical experience and provide real-time feedback. The South Western Ambulance Service NHS Foundation Trust employs senior doctors in their learning and development (L&D) team to support the development of 'train the trainer' courses for L&D officers (LDOs). This short report of a quality improvement initiative describes the implementation and evaluation of a simulation-debrief model of paramedic education. Methods: A quality improvement design was adopted. The train the trainer scenarios for simulation-debrief were designed and written following the trust's training needs analysis by the L&D team. The course ran for two days, and each scenario was facilitated by faculty experienced in simulation (both doctors and paramedics). Low-fidelity mannequins and standard ambulance training kit was used (including response bags, training monitor and defibrillator). Participants' pre- and post-scenario self-reported confidence scores were recorded, and qualitative feedback requested. Numerical data were analysed, and collated into graphs using Excel. Thematic analysis of comments was used to present qualitative themes. The SQUIRE 2.0 checklist for reporting quality improvement initiatives was used to frame this short report. Results: Forty-eight LDOs attended across three courses. All participants reported improved confidence scores in the clinical topic covered after each simulation-debrief scenario, with a minority reporting equivocal scores. Formal qualitative feedback from participants indicated an overwhelmingly positive response to the introduction of simulation-debrief as an education method, and a move away from summative, assessment-based training. The positive value of a multidisciplinary faculty was also reported. Conclusion: The simulation-debrief model of paramedic education represents a move away from the use of didactic teaching and 'tick box'-style assessments in previous train the trainer courses. The introduction of simulation-debrief teaching methodology has had a positive impact on paramedics' confidence in the selected clinical topics, and is seen by LDOs as an effective and valuable education method.

Microbiome induced complement synthesized in the gut protects against enteric infections.

Canonically, complement is a serum-based host defense system that protects against systemic microbial invasion. Little is known about the production and function of complement components on mucosal surfaces. Here we show gut complement component 3 (C3), central to complement function, is regulated by the composition of the microbiota in healthy humans and mice, leading to host-specific gut C3 levels. Stromal cells in intestinal lymphoid follicles (LFs) are the predominant source of intestinal C3. During enteric infection with Citrobacter rodentium or enterohemorrhagic Escherichia coli, luminal C3 levels increase significantly and are required for protection. C. rodentium is remarkably more invasive to the gut epithelium of C3-deficient mice than of wild-type mice. In the gut, C3-mediated phagocytosis of C. rodentium functions to clear pathogens. Our study reveals that variations in gut microbiota determine individuals’ intestinal mucosal C3 levels, dominantly produced by LF stromal cells, which directly correlate with protection against enteric infection. Highlights: Gut complement component 3 (C3) is induced by the microbiome in healthy humans and mice at a microbiota-specific level.Gut stromal cells located in intestinal lymphoid follicles are a major source of luminal C3 During enteric infections with Citrobacter rodentium or enterohemorrhagic Escherichia coli, gut luminal C3 levels increase and are required for protection. C. rodentium is significantly more invasive of the gut epithelium in C3-deficient mice when compared to WT mice. In the gut, C3-mediated opsonophagocytosis of C. rodentium functions to clear pathogens.

Artificial intelligence can detect left ventricular dilatation on contrast-enhanced thoracic computer tomography relative to cardiac magnetic resonance imaging.

OBJECTIVES: To assess the diagnostic accuracy of an automated algorithm to detect left ventricular (LV) dilatation on non-ECG gated CT, using cardiac magnetic resonance (CMR) as reference standard. METHODS: Consecutive patients with contrast-enhanced CT thorax and CMR within 31 days (2016-2020) were analysed (n = 84). LV dilatation was defined against age-, sex- and body surface area-specific values for CMR. CTs underwent automated artificial intelligence(AI)-derived analysis that segmented ventricular chambers, presenting maximal LV diameter and volume. Area under the receiver operator curve (AUC-ROC) analysis identified CT thresholds with ≥90% sensitivity and highest specificity and ≥90% specificity with highest sensitivity. Youden's Index was used to identify thresholds with optimised sensitivity and specificity. RESULTS: Automated diameter analysis was feasible in 92% of cases (77/84; 45 men, age 61 ± 14 years, mean CT to CMR interval 10 ± 8 days). Relative to CMR as a reference standard, 45% had LV dilatation. In males, an automated LV diameter measurement of ≥55.5 mm was ≥90% specific for CMR-defined LV dilatation (positive predictive value (PPV) 85.7%, negative predictive value (NPV) 61.2%, accuracy 68.9%). In females, an LV diameter of ≥49.7 mm was ≥90% specific for CMR-defined LV dilatation (PPV 66.7%, NPV 73.1%, accuracy 71.9%). AI CT volumetry data did not significantly improve AUC performance. CONCLUSION: Fully automated AI-derived analysis LV dilatation on routine unselected non-gated contrast-enhanced CT thorax studies is feasible. We have defined thresholds for the detection of LV dilatation on CT relative to CMR, which could be used to routinely screen for dilated cardiomyopathy at the time of CT. ADVANCES IN KNOWLEDGE: We show, for the first time, that a fully-automated AI-derived analysis of maximal LV chamber axial diameter on non-ECG-gated thoracic CT is feasible in unselected real-world cases and that the derived measures can predict LV dilatation relative to cardiac magnetic resonance imaging, the non-invasive reference standard for determining cardiac chamber size. We have derived sex-specific cut-off values to screen for LV dilatation on routine contrast-enhanced thoracic CT. Future work should validate these thresholds and determine if technology can alter clinical outcomes in a cost-effective manner.

Harnessing CD8+CD28- Regulatory T Cells as a Tool to Treat Autoimmune Disease.

T regulatory cell therapy presents a novel therapeutic strategy for patients with autoimmune diseases or who are undergoing transplantation. At present, the CD4+ Treg population has been extensively characterized, as a result of defined phenotypic and functional readouts. In this review article, we discuss the development and biology of CD8+ Tregs and their role in murine and human disease indications. A subset of CD8+ Tregs that lack the surface expression of CD28 (CD8+CD28- Treg) has proved efficacious in preclinical models. CD8+CD28- Tregs are present in healthy individuals, but their impaired functionality in disease renders them less effective in mediating immunosuppression. We primarily focus on harnessing CD8+ Treg cell therapy in the clinic to support current treatment for patients with autoimmune or inflammatory conditions.

The anti-inflammatory effects of equine bone marrow stem cell-derived extracellular vesicles on autologous chondrocytes.

BACKGROUND: Osteoarthritis (OA) in the horse is an economic and welfare issue and there are no current disease modifying drugs available. Stem cells have been suggested as a therapeutic intervention for OA, originally on the basis of their regenerative capacity. However, it is hypothesised that mesenchymal stem cells (MSC) exert their effects via paracrine factors including the production of extracellular vesicles that can themselves recapitulate the MSC effects in the joint. OBJECTIVES: To isolate extracellular vesicles from bone marrow MSC and investigate their anti-inflammatory effects on chondrocytes. STUDY DESIGN: An in vitro assessment of the effect of direct culturing extracellular vesicles on artificially inflamed chondrocytes. METHODS: Extracellular vesicles were isolated from bone marrow MSC using differential sequential ultracentrifugation. Vesicles were characterised using electron microscopy, nanoparticle tracing analysis and protein analysis. Vesicle internalisation was carried out via vesicles being pre-stained and co-cultured with equine chondrocytes before analysis using confocal microscopy. The effects of vesicles on artificially inflamed chondrocytes was examined using quantitative PCR. RESULTS: To the best of the authors' knowledge, this is the first study to isolate and characterise extracellular vesicles from equine bone MSC. Vesicles were taken up by autologous chondrocytes and had anti-inflammatory effects on gene expression following chondrocyte exposure to tumour necrosis factor α and Interleukin 1ß. MAIN LIMITATIONS: Only three independent biological repeats were performed and the work was done in vitro. CONCLUSION: Extracellular vesicles can be isolated from equine bone marrow MSC; they may be taken up by chondrocytes and have an anti-inflammatory action.

Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.

BACKGROUND: Fibromyalgia and myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) are poorly understood conditions with overlapping symptoms, fuelling debate as to whether they are manifestations of the same spectrum or separate entities. Both are associated with hypermobility, but this remains significantly undiagnosed, despite impact on quality of life. OBJECTIVE: We planned to understand the relevance of hypermobility to symptoms in fibromyalgia and ME/CFS. METHOD: Sixty-three patient participants presented with a confirmed diagnosis of fibromyalgia and/or ME/CFS; 24 participants were healthy controls. Patients were assessed for symptomatic hypermobility. RESULTS: Evaluations showed exceptional overlap in patients between fibromyalgia and ME/CFS, plus 81% met Brighton criteria for hypermobility syndrome (odds ratio 7.08) and 18% met 2017 hypermobile Ehlers-Danlos syndrome (hEDS) criteria. Hypermobility scores significantly predicted symptom levels. CONCLUSION: Symptomatic hypermobility is particularly relevant to fibromyalgia and ME/CFS, and our findings highlight high rates of mis-/underdiagnosis. These poorly understood conditions have a considerable impact on quality of life and our observations have implications for diagnosis and treatment targets.

The role of interleukin-6 trans-signalling on cardiovascular dysfunction in inflammatory arthritis.

OBJECTIVES: Cardiovascular (CV) mortality in RA patients is 50% higher than in the general population. There is increasing recognition that systemic inflammation is a major driver of this. IL-6 is implicated in cardiovascular disease (CVD) in the general population but its role in CVD in RA is undefined. Of the two modes of IL-6 signalling, trans-signalling is pro-inflammatory whereas classical signalling is linked with inflammation resolution. This study examines the role of IL-6 trans-signalling in CVD in a mouse model and patients with RA. METHODS: Myography determined the effect of IL-6 trans-signalling blockade, using sgp130Fc, on aortic constriction in murine collagen-induced arthritis. Serum CCL2 and sVCAM-1 as soluble biomarkers of sIL-6R trans-signalling were investigated in a human cross-sectional study. An observational longitudinal study investigated the association between these biomarkers and progression of subclinical atherosclerosis in early RA by measuring carotid intima-media thickness (CIMT). RESULTS: sgp130Fc reduced arthritis severity, serum CCL2 and sVCAM-1 and restored vascular function in collagen-induced arthritis (CIA). In established RA, sVCAM-1 correlated with the 28-joint DAS (DAS28) and CV risk. In early RA, baseline DAS28 was associated with CIMT change at 6 months. CIMT 'rapid progressors' at 12 months had higher baseline sVCAM-1, haemoglobin A1c, cholesterol:high-density lipoprotein cholesterol ratio and LDL cholesterol. CONCLUSIONS: IL-6 trans-signalling plays a pivotal role in vascular dysfunction in CIA. In early RA, sVCAM-1 was associated with progression of subclinical atherosclerosis. Inflammation from RA onset in CVD-susceptible individuals may accelerate atherosclerosis. IL-6 trans-signalling blockade may be beneficial to RA patients and perhaps for atherosclerosis in the general population.

Return on investment of the diabetes foot care clinical pathway implementation in Alberta, Canada.

AIMS: Based on best practices, the diabetes foot care clinical pathway (DFCCP) has been developed and implemented in several clinics in Alberta, Canada. We performed a return on investment (ROI) analysis of this implementation. METHODS: We used a cohort design comparing both cost and return (in terms of reduced health services utilization, HSU) between diabetes patients who were exposed and who were unexposed, to the intervention. We used a difference-in-difference approach and a propensity-score-matching technique to minimize biases due to differences in demographic and clinical characteristics between two cohorts. We used a 1-year time-horizon and converted all costs/savings to 2019 Canadian dollars (1 CA$ ~= 0.75 US$). RESULTS: The intervention helped avoid $3500 in costs of HSU per patient-year. Subtracting the intervention cost of $500, the net benefit of intervention was $3000 (ranged $2400-$3700) per patient-year. The ROI ratio was estimated at 7.4 (ranged 6.1 to 8.8) meaning that every invested $1 returned $7.4 (ranged $6.1-$8.8) for the health system. The probability of intervention being cost-saving ranged from 99.5-100%. CONCLUSIONS: The implementation of DFCCP in Alberta is cost-saving. A continuation of the pathway implementation at studied clinics and a spread to other clinics are recommended.

CD28- Cells Are Increased in Early Rheumatoid Arthritis and Are Linked With Cytomegalovirus Status.

Objective: CD3+CD8+CD28- cells are higher in Rheumatoid Arthritis (RA). The aim of this study was to assess CD3+CD8+CD28- cells in patients with early RA and assess the effects of cytomegalovirus (CMV) seropositivity. Method: In this prospective observation study, 50 RA patients were recruited from Cardiff University Hospital of Wales (UHW) rheumatology outpatient, 25 patients with early disease (disease duration 0-6 months) and 25 patients with established disease (>2 years). These were compared with 25 healthy controls. Clinical and serological markers of inflammation were noted, and peripheral blood mononuclear cells were analyzed using flow cytometry. Results: The percentage of the CD8+CD28- T cells was increased in RA patients and was associated with disease duration. The percentage of CD8+CD28- T cells was increased in CMV positive early and established RA grouped and early RA patients in comparison to CMV negative patients (p < 0.05). There is a weak but statistically significant correlation between the percentage of CD3+CD8+CD28- cells and CRP in CMV positive RA patients (r = 0.227, p < 0.05). Conclusion: The percentage of CD8+CD28- T cells is higher in RA patients and correlates with disease duration, highlighting a potential role early in the disease process. These cells were also higher in CMV positive early RA patients which may suggest a role of CMV in disease development.

Headache and non-headache symptoms provoked by nitroglycerin in migraineurs: A human pharmacological triggering study.

BACKGROUND: Studying a spontaneous migraine attack is challenging, particularly the earliest components. Nitroglycerin is a potent, reliable and reproducible migraine trigger of the entirety of the migraine attack, making its use experimentally attractive. METHODS: Fifty-three subjects with migraine with a history of spontaneous premonitory symptoms were exposed to a 0.5 mcg/kg/min nitroglycerin infusion. Eighty-three percent (n = 44) developed typical premonitory and headache symptomatology. Fifty-seven percent (n = 25) were invited back to further study visits, during which they were re-exposed to nitroglycerin or placebo infusion in a double-blind randomised design. The phenotype of premonitory symptoms and headache was captured and compared to spontaneous attacks and between triggered attacks using agreement analysis. RESULTS: More premonitory symptoms were triggered with nitroglycerin than placebo (mean symptom difference = 4, t20 = 7.06, p < 0.001). The agreement in triggering for the most commonly reported premonitory symptoms (concentration difficulty and tiredness) was >66%. The retriggering agreement for all but one premonitory symptom was >60%. The agreement in timing to onset of premonitory symptoms was reliable across two triggered attacks. The agreement with spontaneous attacks and between attacks for headache and its associated symptoms, including laterality, was less reliable. CONCLUSIONS: Nitroglycerin can reliably and reproducibly provoke premonitory symptomatology associated with migraine. This forms an ideal model to study the earliest manifestations of migraine attacks.

A Challenging and Unexpected Case of MINOCA Using Multimodality Imaging.

We describe a challenging case of a patient with MINOCA due to isolated right ventricular myocardial infarction with microvascular obstruction identified on cardiac magnetic resonance imaging. This case highlights that even a comprehensive, guideline-based assessment of these patients can initially fail to detect the underlying pathology. (Level of Difficulty: Beginner.).

Nondestructive 3D Imaging and Quantification of Hydrated Biofilm-Sediment Aggregates Using X-ray Microcomputed Tomography.

Biofilm-sediment aggregate (BSA) contains a high water content, either within internal pores and channels or bound by extracellular polymeric substances (EPS) forming a highly hydrated biofilm matrix. Desiccation of BSAs alters the biofilm morphology and thus the physical characteristics of porous media, such as the binding matrix within BSA and internal pore geometry. Observing BSAs in their naturally hydrated form is essential but hampered due to the lack of techniques for imaging and discerning hydrated materials. Generally, imagery techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam nanotomography (FIB-nt)) involve the desiccation of BSAs (freeze-drying or acetone dehydration) or prevent differentiation between BSA components such as inorganic particles and pore water (confocal laser scanning microscopic (CLSM)). Here, we propose a novel methodology that simultaneously achieves the 3D visualization and quantification of BSAs and their components in their hydrated form at a submicron resolution using X-ray microcomputed tomography (µ-CT). It enables the high-resolution detection of comparable morphology of multiphase components within a hydrated aggregate: each single inorganic particle and the hydrated biofilm matrix. This allows the estimation of aggregate density and the illustration of biofilm-sediment binding matrix. This information provides valuable insights into investigations of the transport of BSAs and aggregate-associated sediment particles, contaminants (such as microplastics), organic carbon, and their impacts on aquatic biogeochemical cycling.

Lesson of the month 2: Pulmonary embolism in a patient on rivaroxaban and concurrent carbamazepine.

A 71-year-old female with a history of pulmonary embolism treated with rivaroxaban presented with acute onset shortness of breath, chest pain and palpitations. Computed tomographic pulmonary angiography (CTPA) revealed multiple bilateral pulmonary emboli. The patient was concurrently prescribed carbamazepine and was later diagnosed with recurrence of breast cancer during the admission. We discuss common drug interactions pertinent to direct oral anticoagulants (DOACs) that can increase the risk of further venous thromboembolism. This case report highlights the importance of reviewing patient medications when considering anticoagulants and the need to raise awareness of these drug interactions among clinicians when making their choice of anticoagulation. It also reinforces the current lack of evidence for use of DOACs in patients with solid organ malignancies.

Prolonged viral replication and longitudinal viral dynamic differences among respiratory syncytial virus infected infants.

BackgroundLongitudinal respiratory syncytial virus (RSV) dynamics have not been well studied despite the existence of factors favoring prolonged RSV replication including high mutation rates allowing rapid evolution and potential escape from immune control. We therefore measured viral load in previously RSV-naive infants over prolonged time spans.MethodsDuring 2014-2015, quantitative nasal aspirates were collected from 51 RSV-PCR+ infants. Multiple parallel assessments of viral loads were quantified at each collected time point using a well-validated real-time quantitative reverse transcriptase polymerase chain reaction assay. After observing viral load rebound phenomenon in some infants, the viral dynamics of 27 infants with sufficient longitudinal viral load data points were analyzed using the pre-defined criteria for viral rebound. Additional analyses were performed comparing age with viral rebound, viral clearance rates, and viral load area-under-the-curve (AUCVL).ResultsThe 51 infants (303 nasal aspirate samples; mean of 5.9 per patient) exhibited slower than expected viral clearance. Lower age trended toward slower viral clearance and greater AUCVL. Six infants had detectable viral loads ≥1 month after symptom onset. Ten of twenty-seven evaluable subjects exhibited viral rebound and this rebound was age-dependent (P=0.0259). All but one rebounder were <70 days old.ConclusionInfants struggle to control primary RSV infections allowing prolonged viral replication and previously undescribed viral rebound; likely representing viral mutational immune escape.

Anti cytokine therapy in chronic inflammatory arthritis.

This is a review looking at anti cytokine therapy in Rheumatoid Arthritis (RA), Psoriatic Arthritis (PSA) and Ankylosing Spondylitis (AS). The review explores the similarities and differences in the clinical features, as well as treatments and cytokines involved in the development and propagation of the disease. Particular attention is paid to TNFα inhibitors IL-1ra, IL-6 and JAK kinase Inhibitors, anti IL23 and IL-12 and the new developments with anti-IL-17.