Incidence, prevalence, and co-occurrence of autoimmune disorders over time and by age, sex, and socioeconomic status: a population-based cohort study of 22 million individuals in the UK.

BACKGROUND: A rise in the incidence of some autoimmune disorders has been described. However, contemporary estimates of the overall incidence of autoimmune diseases and trends over time are scarce and inconsistent. We aimed to investigate the incidence and prevalence of 19 of the most common autoimmune diseases in the UK, assess trends over time, and by sex, age, socioeconomic status, season, and region, and we examine rates of co-occurrence among autoimmune diseases. METHODS: In this UK population-based study, we used linked primary and secondary electronic health records from the Clinical Practice Research Datalink (CPRD), a cohort that is representative of the UK population in terms of age and sex and ethnicity. Eligible participants were men and women (no age restriction) with acceptable records, approved for Hospital Episodes Statistics and Office of National Statistics linkage, and registered with their general practice for at least 12 months during the study period. We calculated age and sex standardised incidence and prevalence of 19 autoimmune disorders from 2000 to 2019 and used negative binomial regression models to investigate temporal trends and variation by age, sex, socioeconomic status, season of onset, and geographical region in England. To characterise co-occurrence of autoimmune diseases, we calculated incidence rate ratios (IRRs), comparing incidence rates of comorbid autoimmune disease among individuals with a first (index) autoimmune disease with incidence rates in the general population, using negative binomial regression models, adjusted for age and sex. FINDINGS: Among the 22 009 375 individuals included in the study, 978 872 had a new diagnosis of at least one autoimmune disease between Jan 1, 2000, and June 30, 2019 (mean age 54·0 years [SD 21·4]). 625 879 (63·9%) of these diagnosed individuals were female and 352 993 (36·1%) were male. Over the study period, age and sex standardised incidence rates of any autoimmune diseases increased (IRR 2017-19 vs 2000-02 1·04 [95% CI 1·00-1·09]). The largest increases were seen in coeliac disease (2·19 [2·05-2·35]), Sjogren's syndrome (2·09 [1·84-2·37]), and Graves' disease (2·07 [1·92-2·22]); pernicious anaemia (0·79 [0·72-0·86]) and Hashimoto's thyroiditis (0·81 [0·75-0·86]) significantly decreased in incidence. Together, the 19 autoimmune disorders examined affected 10·2% of the population over the study period (1 912 200 [13·1%] women and 668 264 [7·4%] men). A socioeconomic gradient was evident across several diseases, including pernicious anaemia (most vs least deprived area IRR 1·72 [1·64-1·81]), rheumatoid arthritis (1·52 [1·45-1·59]), Graves' disease (1·36 [1·30-1·43]), and systemic lupus erythematosus (1·35 [1·25-1·46]). Seasonal variations were observed for childhood-onset type 1 diabetes (more commonly diagnosed in winter) and vitiligo (more commonly diagnosed in summer), and regional variations were observed for a range of conditions. Autoimmune disorders were commonly associated with each other, particularly Sjögren's syndrome, systemic lupus erythematosus, and systemic sclerosis. Individuals with childhood-onset type 1 diabetes also had significantly higher rates of Addison's disease (IRR 26·5 [95% CI 17·3-40·7]), coeliac disease (28·4 [25·2-32·0]), and thyroid disease (Hashimoto's thyroiditis 13·3 [11·8-14·9] and Graves' disease 6·7 [5·1-8·5]), and multiple sclerosis had a particularly low rate of co-occurrence with other autoimmune diseases. INTERPRETATION: Autoimmune diseases affect approximately one in ten individuals, and their burden continues to increase over time at varying rates across individual diseases. The socioeconomic, seasonal, and regional disparities observed among several autoimmune disorders in our study suggest environmental factors in disease pathogenesis. The inter-relations between autoimmune diseases are commensurate with shared pathogenetic mechanisms or predisposing factors, particularly among connective tissue diseases and among endocrine diseases. FUNDING: Research Foundation Flanders.

Autoimmune diseases and cardiovascular risk: a population-based study on 19 autoimmune diseases and 12 cardiovascular diseases in 22 million individuals in the UK.

BACKGROUND: Some autoimmune diseases are associated with an increased risk of cardiovascular disease. We aimed to determine whether or not this is true, and to what extent, for a broad range of autoimmune conditions. METHODS: In this population-based study, we used linked primary and secondary care records from the Clinical Practice Research Datalink (CPRD), GOLD and Aurum datasets, to assemble a cohort of individuals across the UK who were newly diagnosed with any of 19 autoimmune diseases between Jan 1, 2000, and Dec 31, 2017, younger than 80 years at diagnosis, and free of cardiovascular diseases up to 12 months after diagnosis. We also assembled a matched cohort with up to five individuals matched on age, sex, socioeconomic status, region, and calendar year, who were free of autoimmune disease and free of cardiovascular diseases up to 12 months after study entry. Both cohorts were followed up until June 30, 2019. We investigated the incidence of 12 cardiovascular outcomes and used Cox proportional hazards models to examine differences in patients with and without autoimmune diseases. FINDINGS: Of 22 009 375 individuals identified from the CPRD databases, we identified 446 449 eligible individuals with autoimmune diseases and 2 102 830 matched controls. In the autoimmune cohort, mean age at diagnosis was 46·2 years (SD 19·8), and 271 410 (60·8%) were women and 175 039 (39·2%) were men. 68 413 (15·3%) people with and 231 410 (11·0%) without autoimmune diseases developed incident cardiovascular disease during a median of 6·2 years (IQR 2·7-10·8) of follow-up. The incidence rate of cardiovascular disease was 23·3 events per 1000 patient-years among patients with autoimmune disease and 15·0 events per 1000 patient-years among those without an autoimmune disease (hazard ratio [HR] 1·56 [95% CI 1·52-1·59]). An increased risk of cardiovascular disease with autoimmune disease was seen for every individual cardiovascular disease and increased progressively with the number of autoimmune diseases present (one disease: HR 1·41 [95% CI 1·37-1·45]; two diseases: 2·63 [2·49-2·78]); three or more diseases: 3·79 [3·36-4·27]), and in younger age groups (age <45 years: 2·33 [2·16-2·51]; 55-64 years: 1·76 [1·67-1·85]; ≥75 years: 1·30 [1·24-1·36]). Among autoimmune diseases, systemic sclerosis (3·59 [2·81-4·59]), Addison's disease (2·83 [1·96-4·09]), systemic lupus erythematosus (2·82 [2·38-3·33]), and type 1 diabetes (2·36 [2·21-2·52]) had the highest overall cardiovascular risk. INTERPRETATION: These findings warrant targeted cardiovascular prevention measures, in particular in younger patients with autoimmune diseases, and further research into pathophysiological mechanisms underlying these complications. FUNDING: Horizon 2020 Marie Sklodowska-Curie Actions and European Society of Cardiology.

A Phase II randomized controlled trial of oral prednisolone in early diffuse cutaneous systemic sclerosis (PRedSS).

OBJECTIVES: Although the painful and disabling features of early diffuse cutaneous SSc (dcSSc) have an inflammatory basis and could respond to corticosteroids, corticosteroids are a risk factor for scleroderma renal crisis. Whether or not they should be prescribed is therefore highly contentious. Our aim was to examine safety and efficacy of moderate-dose prednisolone in early dcSSc. METHODS: PRedSS set out as a Phase II, multicentre, double-blind randomized controlled trial, converted to open-label during the Covid-19 pandemic. Patients were randomized to receive either prednisolone (∼0.3 mg/kg) or matching placebo (or no treatment during open-label) for 6 months. Co-primary endpoints were the HAQ Disability Index (HAQ-DI) and modified Rodnan skin score (mRSS) at 3 months. Over 20 secondary endpoints included patient reported outcome measures reflecting pain, itch, fatigue, anxiety and depression, and helplessness. Target recruitment was 72 patients. RESULTS: Thirty-five patients were randomized (17 prednisolone, 18 placebo/control). The adjusted mean difference between treatment groups at 3 months in HAQ-DI score was -0.10 (97.5% CI: -0.29, 0.10), P = 0.254, and in mRSS -3.90 (97.5% CI: -8.83, 1.03), P = 0.070, both favouring prednisolone but not significantly. Patients in the prednisolone group experienced significantly less pain (P = 0.027), anxiety (P = 0.018) and helplessness (P = 0.040) than control patients at 3 months. There were no renal crises, but sample size was small. CONCLUSION: PRedSS was terminated early primarily due to the Covid-19 pandemic, and so was underpowered. Therefore, interpretation must be cautious and results considered inconclusive, indicating the need for a further randomized trial. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT03708718.

Hematoma Resolution In Vivo Is Directed by Activating Transcription Factor 1.

RATIONALE: The efficient resolution of tissue hemorrhage is an important homeostatic function. In human macrophages in vitro, heme activates an AMPK (AMP-activated protein kinase)/ATF1 (activating transcription factor-1) pathway that directs Mhem macrophages through coregulation of HO-1 (heme oxygenase-1; HMOX1) and lipid homeostasis genes. OBJECTIVE: We asked whether this pathway had an in vivo role in mice. METHODS AND RESULTS: Perifemoral hematomas were used as a model of hematoma resolution. In mouse bone marrow-derived macrophages, heme induced HO-1, lipid regulatory genes including LXR (lipid X receptor), the growth factor IGF1 (insulin-like growth factor-1), and the splenic red pulp macrophage gene Spic. This response was lost in bone marrow-derived macrophages from mice deficient in AMPK (Prkab1-/-) or ATF1 (Atf1-/-). In vivo, femoral hematomas resolved completely between days 8 and 9 in littermate control mice (n=12), but were still present at day 9 in mice deficient in either AMPK (Prkab1-/-) or ATF1 (Atf1-/-; n=6 each). Residual hematomas were accompanied by increased macrophage infiltration, inflammatory activation and oxidative stress. We also found that fluorescent lipids and a fluorescent iron-analog were trafficked to lipid-laden and iron-laden macrophages respectively. Moreover erythrocyte iron and lipid abnormally colocalized in the same macrophages in Atf1-/- mice. Therefore, iron-lipid separation was Atf1-dependent. CONCLUSIONS: Taken together, these data demonstrate that both AMPK and ATF1 are required for normal hematoma resolution. Graphic Abstract: An online graphic abstract is available for this article.

Norm-Based Cutoffs as Predictors of Prolonged Recovery After Adolescent Sport-Related Concussion.

OBJECTIVES: To identify predictors of prolonged recovery (ie, >28 days) using patient demographic factors and healthy, norm-based cutoffs on a multimodal test battery in adolescents after sport-related concussions (SRCs). DESIGN: Retrospective cohort. Patients were deemed recovered after successful completion of return-to-play/school protocols and received medical clearance. SETTING: Community concussion clinic. PATIENTS: Male and female adolescent student athletes diagnosed with a SRC and evaluated within 1 week of injury. INDEPENDENT VARIABLES: Patient demographics, medical history, injury description, computerized neurocognitive testing, vestibular/ocular testing, and symptoms at initial clinical visit. MAIN OUTCOME MEASURES: Performance on clinical testing to predict recovery duration, classified as normal (<28 days) or prolonged (>28 days). RESULTS: A total of 201 adolescent student athletes (age = 15.3 ± 1.4 years) were included (female 35%). Average recovery duration for the entire cohort was 22.3 ± 13.3 days, with 22% (n = 45) of adolescent student athletes taking >28 days to recover. The final model was 88.3% accurate in classifying normal and prolonged recovery. Predictor variables included sex, loss of consciousness, history of ocular disorder, history of concussion, performance on visual motor speed composite, visual motion sensitivity symptom provocation and near point of convergence distance, number-naming total time, and symptom count. CONCLUSIONS: These findings suggest that using norm-based cutoffs from cognitive, oculomotor, and vestibulo-ocular testing and symptom reporting, clinicians can accurately predict a prolonged recovery (sensitivity = 81%) and normal recovery (specificity = 83%) in an adolescent, SRC cohort.

Arterial Stiffness and Cardiorespiratory Fitness Are Associated With Cognitive Function in Older Adults.

Age-related cognitive impairment has been associated with arterial stiffening and decreased cardiorespiratory fitness. The aims of this cross-sectional study were to compare cognitive function domains and cardiovascular parameters in older adults (≥ 65 years old) with high and normal aortic stiffness (via carotid-femoral pulse wave velocity, cfPWV) and to explore relationships among cfPWV, carotid intima-media thickness, cardiorespiratory fitness, and cognitive function. Vascular and cognitive function were measured in older adults with either normal or high cfPWV. Cognitive function was measured via an intensive one-time neuropsychological battery, while cfPWV by applanation tonometry, carotid intima-media thickness and function (i.e., distensibility) by ultrasonography, and cardiorespiratory fitness (i.e., VO2peak) by a submaximal exercise test. Correlations among age, VO2peak, carotid intima-media thickness, cfPWV, and cognitive function were performed along with a series of multivariate analyses of variance. Compared with NAS, participants with HAS had greater aortic, carotid, and brachial blood pressures but similar cardiorespiratory fitness and carotid intima-media thickness and distensibility. Participants with NAS exhibited better neuropsychological performance in executive function and attention and overall cognitive function than those with HAS. When controlling for age, visual scanning and perception scores were correlated with cfPWV and VO2peak. Our findings suggest that certain cognitive domains for older adults are associated with their cardiorespiratory fitness and aortic stiffness.

A Coumarin-Porphyrin FRET Break-Apart Probe for Heme Oxygenase-1.

Heme oxygenase-1 (HO-1) is a vital enzyme in humans that primarily regulates free heme concentrations. The overexpression of HO-1 is commonly associated with cardiovascular and neurodegenerative diseases including atherosclerosis and ischemic stroke. Currently, there are no known chemical probes to detect HO-1 activity, limiting its potential as an early diagnostic/prognostic marker in these serious diseases. Reported here are the design, synthesis, and photophysical and biological characterization of a coumarin-porphyrin FRET break-apart probe to detect HO-1 activity, Fe-L1. We designed Fe-L1 to "break-apart" upon HO-1-catalyzed porphyrin degradation, perturbing the efficient FRET mechanism from a coumarin donor to a porphyrin acceptor fluorophore. Analysis of HO-1 activity using Escherichia coli lysates overexpressing hHO-1 found that a 6-fold increase in emission intensity at 383 nm was observed following incubation with NADPH. The identities of the degradation products following catabolism were confirmed by MALDI-MS and LC-MS, showing that porphyrin catabolism was regioselective at the α-position. Finally, through the analysis of Fe-L2, we have shown that close structural analogues of heme are required to maintain HO-1 activity. It is anticipated that this work will act as a foundation to design and develop new probes for HO-1 activity in the future, moving toward applications of live fluorescent imaging.

ANCA in systemic sclerosis, when vasculitis overlaps with vasculopathy: a devastating combination of pathologies.

In patients with SSc, the coexistence of ANCA-associated vasculitis (SSc-AAV) has been reported to be associated with a severe disease course, including significant pulmonary and renal involvement. The presence of ANCA is not uncommon in patients with SSc, and therefore clinicians must maintain a high index of clinical suspicion about SSc-AAV. p-ANCA and anti-myeloperoxidase antibodies are the most common antibodies observed. Patients typically present with clinical features of microscopic polyangiitis or renal-limited vasculitis. There are multiple areas of potential interaction in the pathogenesis of SSc and AAV, which can exacerbate/compound vascular disease. In addition, similar patterns of major internal organ involvement (e.g. lung and kidneys) are seen in both conditions. We highlight a diagnostic approach to SSc-AAV and the paucity of data to inform management. As such, SSc-AAV is typically treated as per isolated AAV, which can potentially be hazardous in patients with SSc (e.g. due to the association between high-dose steroid and scleroderma renal crisis). We propose that this rare clinical entity warrants rigorous investigation, including definition of a therapeutic strategy to ameliorate the potentially devastating combination of pathologies in SSc-AAV.

Blood Biomarkers for Monitoring and Prognosis of Large Vessel Vasculitides.

PURPOSE OF REVIEW: Large vessel vasculitides (LVVs) are inflammatory conditions of the wall of large-sized arteries, mainly represented by giant cell arteritis (GCA) and Takayasu arteritis (TA). The inflammatory process within the vessel wall can lead to serious consequences such as development of aneurysms, strokes and blindness; therefore, early diagnosis and follow-up of LVV are fundamental. However, the arterial wall is poorly accessible and blood biomarkers are intended to help physicians not only in disease diagnosis but also in monitoring and defining the prognosis of these conditions, thus assisting therapeutic decisions and favouring personalised management. The field is the object of intense research as the identification of reliable biomarkers is likely to shed light on the mechanisms of disease progression and arterial remodelling. In this review, we will discuss the role of blood biomarkers in LVVs in the light of the latest evidence. RECENT FINDINGS: In clinical practice, the most widely performed laboratory investigations are the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). However, these indices may be within normal limits during disease relapse and they are not reliable in patients receiving interleukin-6 (IL-6) receptor inhibitors. New biomarkers struggle to gain traction in clinical practice and no molecule with good accuracy has been identified to date. IL-6, a pro-inflammatory cytokine that drives CRP synthesis and increases the ESR, is one of the most promising biomarkers in the field. IL-6 analysis is increasingly performed, and serum levels are more sensitive than ESR for active GCA and might reflect persistent inflammation with high risk of relapse in patients on IL-6 receptor inhibitors. A future with biomarkers that reflect different disease features is an important aspiration. Accordingly, intense effort is being made to identify IL-6-independent inflammatory biomarkers, such as S100 proteins, pentraxin-3 and osteopontin. Moreover, metalloproteinases such as MMP2/9 and angiogenic modulators such as VEGF, YLK-40 and angiopoietins are being studied as markers of arterial remodelling. Lastly, biomarkers indicating organ damage may guide prognostic stratification as well as emergency therapeutic decisions: the most promising biomarkers so far identified are NT-proBNP, which reflects myocardial strain; pentraxin-3, which has been associated with recent optic nerve ischemia; and endothelin-1, which is associated with ischaemic complications. Currently, the use of these molecules in clinical practice is limited because of their restricted availability, lack of sufficient studies supporting their validity and associated costs. Further evidence is required to better interpret their biological and clinical value.

Proarrhythmic electrophysiological and structural remodeling in rheumatoid arthritis.

Chronic inflammatory disorders, including rheumatoid arthritis (RA), are associated with a twofold increase in the incidence of sudden cardiac death (SCD) compared with the healthy population. Although this is partly explained by an increased prevalence of coronary artery disease, growing evidence suggests that ischemia alone cannot completely account for the increased risk. The present review explores the mechanisms of cardiac electrophysiological remodeling in response to chronic inflammation in RA. In particular, it focuses on the roles of nonischemic structural remodeling, altered cardiac ionic currents, and autonomic nervous system dysfunction in ventricular arrhythmogenesis and SCD. It also explores whether common genetic elements predispose to both RA and SCD. Finally, it evaluates the potential dual effects of disease-modifying therapy in both diminishing and promoting the risk of ventricular arrhythmias and SCD.

Biologic therapy in supra-aortic Takayasu arteritis can improve symptoms of cerebral ischaemia without surgical intervention.

OBJECTIVES: Takayasu arteritis commonly results in severe arterial injury with stenoses, occlusions and occasionally aneurysms. Arterial disease may compromise organ blood flow and result in significant cardiovascular morbidity and premature mortality. Involvement of the supra-aortic arteries is common, and in its most severe form may compromise cerebral blood supply, resulting in signs of cerebral ischaemia including visual impairment, dysphasia, transient hemiparesis, loss of consciousness and stroke. In addition to combination immunosuppression, the management paradigm for symptomatic cerebral ischaemia includes revascularization. The invasive nature of this surgery, the risk of complications and the relatively high rate of re-stenosis is of concern to patients and their physicians alike. The aim of this study was to determine whether combined immunosuppression with early escalation to biologic therapy improved outcomes and reduced the need for high risk surgical intervention. METHODS: A retrospective review of 145 Takayasu arteritis patients attending Imperial College Healthcare between 2010-2018 was conducted to identify those with cerebral ischaemia secondary to supra-aortic disease and to analyse their treatment and outcomes. RESULTS: Eight patients (5.5%) were identified. Seven patients received long-term combined immunosuppressive therapy and six were prescribed biologics. The data revealed a higher than expected comprehensive response to therapy, with significant falls in disease activity, the cerebral ischaemia score and the prednisolone dose required, over a median follow-up of 37 months. Serial imaging analysis detected no arterial disease progression after the initiation of optimal therapy. Only one patient required surgical intervention for persistent neurological symptoms. CONCLUSION: Early use of biologic therapy in those with supra-aortic Takayasu arteritis presenting with cerebral ischaemia may reduce the numbers of patients requiring surgical intervention and improve outcomes.

Novel Positron Emission Tomography Tracers for Imaging Vascular Inflammation.

PURPOSE OF REVIEW: To provide a focused update on recent advances in positron emission tomography (PET) imaging in vascular inflammatory diseases and consider future directions in the field. RECENT FINDINGS: While PET imaging with 18F-fluorodeoxyglucose (FDG) can provide a useful marker of disease activity in several vascular inflammatory diseases, including atherosclerosis and large-vessel vasculitis, this tracer lacks inflammatory cell specificity and is not a practical solution for imaging the coronary vasculature because of avid background myocardial signal. To overcome these limitations, research is ongoing to identify novel PET tracers that can more accurately track individual components of vascular immune responses. Use of these novel PET tracers could lead to a better understanding of underlying disease mechanisms and help inform the identification and stratification of patients for newly emerging immune-modulatory therapies. Future research is needed to realise the true clinical translational value of PET imaging in vascular inflammatory diseases.

Multi-functional mechanisms of immune evasion by the streptococcal complement inhibitor C5a peptidase.

The complement cascade is crucial for clearance and control of invading pathogens, and as such is a key target for pathogen mediated host modulation. C3 is the central molecule of the complement cascade, and plays a vital role in opsonization of bacteria and recruitment of neutrophils to the site of infection. Streptococcal species have evolved multiple mechanisms to disrupt complement-mediated innate immunity, among which ScpA (C5a peptidase), a C5a inactivating enzyme, is widely conserved. Here we demonstrate for the first time that pyogenic streptococcal species are capable of cleaving C3, and identify C3 and C3a as novel substrates for the streptococcal ScpA, which are functionally inactivated as a result of cleavage 7 amino acids upstream of the natural C3 convertase. Cleavage of C3a by ScpA resulted in disruption of human neutrophil activation, phagocytosis and chemotaxis, while cleavage of C3 generated abnormally-sized C3a and C3b moieties with impaired function, in particular reducing C3 deposition on the bacterial surface. Despite clear effects on human complement, expression of ScpA reduced clearance of group A streptococci in vivo in wildtype and C5 deficient mice, and promoted systemic bacterial dissemination in mice that lacked both C3 and C5, suggesting an additional complement-independent role for ScpA in streptococcal pathogenesis. ScpA was shown to mediate streptococcal adhesion to both human epithelial and endothelial cells, consistent with a role in promoting bacterial invasion within the host. Taken together, these data show that ScpA is a multi-functional virulence factor with both complement-dependent and independent roles in streptococcal pathogenesis.

Takayasu arteritis: advanced understanding is leading to new horizons.

Although outcomes in Takayasu arteritis (TAK) are improving, diagnosis is typically delayed and significant arterial injury accrues. While wider use of non-invasive imaging is impacting this, the onus remains with clinicians to consider a diagnosis of TAK earlier. Meanwhile, morbidity and mortality in TAK remains increased. Herein we review the current situation, outline recent advances and summarize remaining challenges. Understanding of disease pathogenesis remains poor. However, recent genetic data and identification of pathogenic cytokines may facilitate the search for biomarkers capable of distinguishing active and inactive disease, inflammatory and non-inflammatory arterial remodelling. Imaging is critical for TAK, and each modality has important strengths and limitations. Dependence upon CS therapy remains too high. However, the impact of combination immunosuppressive therapy is now recognized, biologic therapies are increasingly available and new agents offer promise. Multicentre clinical trials are now required, and these will depend upon development of defined clinical and imaging end-points.

Identification of an activated neutrophil phenotype in polymyalgia rheumatica during steroid treatment: a potential involvement of immune cell cross-talk.

We have reported the existence of a distinct neutrophil phenotype in giant cell arteritis (GCA) patients arising at week 24 of steroid treatment. In the present study, we investigated whether longitudinal analysis of neutrophil phenotype in patients with polymyalgia rheumatica (PMR) could reveal a novel association with disease status and immune cell cross-talk. Thus, we monitored PMR patient neutrophil phenotype and plasma microvesicle (MV) profiles in blood aliquots collected pre-steroid, and then at weeks 1, 4, 12 and 24 post-steroid treatment.Using flow cytometric and flow chamber analyses, we identified 12-week post-steroid as a pivotal time-point for a marked degree of neutrophil activation, correlating with disease activity. Analyses of plasma MVs indicated elevated AnxA1+ neutrophil-derived vesicles which, in vitro, modulated T-cell reactivity, suggesting distinct neutrophil phenotypic and cross-talk changes at 24 weeks, but not at 12-week post-steroid.Together, these data indicate a clear distinction from GCA patient neutrophil and MV signatures, and provide an opportunity for further investigations on how to 'stratify' PMR patients and monitor their clinical responses through novel use of blood biomarkers.

Zebrafish Model for Functional Screening of Flow-Responsive Genes.

OBJECTIVE: Atherosclerosis is initiated at branches and bends of arteries exposed to disturbed blood flow that generates low shear stress. This mechanical environment promotes lesions by inducing endothelial cell (EC) apoptosis and dysfunction via mechanisms that are incompletely understood. Although transcriptome-based studies have identified multiple shear-responsive genes, most of them have an unknown function. To address this, we investigated whether zebrafish embryos can be used for functional screening of mechanosensitive genes that regulate EC apoptosis in mammalian arteries. APPROACH AND RESULTS: First, we demonstrated that flow regulates EC apoptosis in developing zebrafish vasculature. Specifically, suppression of blood flow in zebrafish embryos (by targeting cardiac troponin) enhanced that rate of EC apoptosis (≈10%) compared with controls exposed to flow (≈1%). A panel of candidate regulators of apoptosis were identified by transcriptome profiling of ECs from high and low shear stress regions of the porcine aorta. Genes that displayed the greatest differential expression and possessed 1 to 2 zebrafish orthologues were screened for the regulation of apoptosis in zebrafish vasculature exposed to flow or no-flow conditions using a knockdown approach. A phenotypic change was observed in 4 genes; p53-related protein (PERP) and programmed cell death 2-like protein functioned as positive regulators of apoptosis, whereas angiopoietin-like 4 and cadherin 13 were negative regulators. The regulation of perp, cdh13, angptl4, and pdcd2l by shear stress and the effects of perp and cdh13 on EC apoptosis were confirmed by studies of cultured EC exposed to flow. CONCLUSIONS: We conclude that a zebrafish model of flow manipulation coupled to gene knockdown can be used for functional screening of mechanosensitive genes in vascular ECs, thus providing potential therapeutic targets to prevent or treat endothelial injury at atheroprone sites.

18F-FDG PET reveals unique features of large vessel inflammation in patients with Takayasu's arteritis.

PURPOSE: The object of this study was to assess whether 18F-fluorodeoxyglucose PET/CT (FDG PET/CT) provides novel information in patients with Takayasu's arteritis (TA) in addition to that provided by current activity assessment, to analyse the effects of possible confounders, such as arterial grafts, and to verify whether PET/CT could be informative in lesions <4 mm thick. METHODS: We studied 30 patients with TA, evaluated from October 2010 to April 2014 by both PET/CT and magnetic resonance imaging (MRI). All arterial lesions were evaluated by PET both qualitatively (positive/negative) and semiquantitatively (maximum standardized uptake value, SUVmax), and the thickness of lesions in the MRI field of view was evaluated. In a per-patient analysis, the relationships between the PET data and acute-phase reactants and NIH criteria for active TA were evaluated. In a per-lesion analysis, the relationships between the PET features of each lesion and MRI morphological data were evaluated. The effects of the presence of arterial grafts were also evaluated. RESULTS: Increased FDG uptake was seen in 16 of 30 patients (53%) and in 46 of 177 vascular lesions (26%). Significant periprosthetic FDG uptake was seen in 6 of 7 patients (86%) with previous vascular surgery and in 10 of 11 of grafts (91%). Graft-associated uptake influenced the PET results in three patients (10%) and the SUVmax values in five patients (17%). Of 39 lesions with significant FDG uptake, 15 (38%) were <4 mm thick. Lesion thickness was correlated with lesion SUVmax in FDG-avid lesions only. FDG arterial uptake was not associated with systemic inflammation or NIH criteria. CONCLUSIONS: PET/CT reveals unique and fundamental features of arterial involvement in TA. PET/CT may be useful in the assessment of local inflammatory and vascular remodelling events independent of systemic inflammation during follow-up, even in lesions in which the arterial wall is <4 mm. The presence of arterial grafts is a potential confounder. Prospective studies are required to correlate PET findings with relevant clinical outcomes.

Investigational analysis reveals a potential role for neutrophils in giant-cell arteritis disease progression.

RATIONALE: Giant-cell arteritis (GCA) is a large-vessel vasculitis characterized by immune cell infiltration, yet the potential involvement of neutrophils has rarely been studied. OBJECTIVE: We investigated whether alterations in neutrophil reactivity occurred in the pathogenesis of GCA or during its clinical management with a canonical glucocorticoid dose regimen during a 6-month period. METHODS AND RESULTS: Blood samples were taken within 48 hours of therapy commencement and at weeks 1, 4, and 24 after glucocorticoid dose. Flow cytometric analysis revealed 3 distinct neutrophil populations and phenotypes. Within 48 hours of steroid treatment, neutrophils displayed an AnxA1(hi)CD62L(lo)CD11b(hi) phenotype, whereas week 1 neutrophils were AnxA1(hi)CD62L(lo)CD11b(lo) and displayed minimal adhesion to endothelial monolayers under flow, and week 24 (i.e., lowest glucocorticoid dose) neutrophils were AnxA1(hi)CD62L(hi)CD11b(hi) with increased endothelial adhesion under flow. Week 24 plasma analyses showed high levels of C-X-C motif chemokine ligand 5, interleukin (IL) 8, IL-17, and IL-6. Importantly, comparison of week 1 and week 24 samples revealed a suppressive neutrophil effect on T-cell proliferation at the former time point only. Finally, in vitro incubation of naive neutrophils with concentrations of IL-6 and IL-17 quantified in GCA plasma at weeks 1 and 24 replicated this differential modulation of lymphocyte proliferation. CONCLUSIONS: This translational study highlights a novel clinical manifestation of GCA, with evidence for a neutrophil component and an escaped proinflammatory phenotype when glucocorticoid therapy is tapered. These results indicate potential involvement of neutrophils in GCA pathogenesis.

Synergistic therapeutic vascular cytoprotection against complement-mediated injury induced via a PKCα-, AMPK-, and CREB-dependent pathway.

Endothelial injury and dysfunction precede accelerated arterial disease in allograft vasculopathy and systemic autoimmune diseases and involve pathogenic Abs and complement. Recent reports suggest that switching to rapamycin from calcineurin antagonists reduces posttransplant vasculopathy and prolongs survival following cardiac transplantion. The majority of these patients also receive statin therapy. We examined potential mechanisms underlying this protective response in human endothelial cells and identified synergy between rapamycin and atorvastatin. Mechanistically, atorvastatin and rapamycin activated a protein kinase Cα, AMP-activated kinase, and CREB-dependent vasculoprotective pathway, which induced decay-accelerating factor (DAF) promoter activity via binding to the cAMP response element, mutation of which attenuated promoter activity. This response significantly increased endothelial cell surface DAF and enhanced protection against complement-mediated injury. Synergy with rapamycin was reproduced by simvastatin, whereas combining atorvastatin with cyclosporine or mycophenolate in place of rapamycin was ineffective. Importantly, synergy was reproduced in vivo, in which only atorvastatin and rapamycin therapy in combination was sufficient to induce DAF on murine aortic endothelium. We believe this pathway represents an important therapeutically inducible vasculoprotective mechanism for diseases mediated by pathogenic Abs and complement, including posttransplant vasculopathy and systemic lupus erythematosus. Although our study focuses on the vascular endothelium, the findings are likely to be broadly applicable, given the diverse cellular expression of DAF.