ROS-producing immature neutrophils in giant cell arteritis are linked to vascular pathologies.

Giant cell arteritis (GCA) is a common form of primary systemic vasculitis in adults, with no reliable indicators of prognosis or treatment responses. We used single cell technologies to comprehensively map immune cell populations in the blood of patients with GCA and identified the CD66b+CD15+CD10lo/-CD64- band neutrophils and CD66bhiCD15+CD10lo/-CD64+/bright myelocytes/metamyelocytes to be unequivocally associated with both the clinical phenotype and response to treatment. Immature neutrophils were resistant to apoptosis, remained in the vasculature for a prolonged period of time, interacted with platelets, and extravasated into the tissue surrounding the temporal arteries of patients with GCA. We discovered that immature neutrophils generated high levels of extracellular reactive oxygen species, leading to enhanced protein oxidation and permeability of endothelial barrier in an in vitro coculture system. The same populations were also detected in other systemic vasculitides. These findings link functions of immature neutrophils to disease pathogenesis, establishing a clinical cellular signature of GCA and suggesting different therapeutic approaches in systemic vascular inflammation.

Abdominal adipose tissue predicts major cardiovascular events in systemic necrotising vasculitides.

OBJECTIVES: Cardiovascular (CV) events are highly prevalent in systemic necrotising vasculitides (SNV). Visceral/subcutaneous adipose tissue (VAT/SAT) ratio has been shown to be associated with CV events in various diseases. We aimed to assess the relevance of abdominal adipose tissue measurement to predict major CV events (MCVEs) in SNV. METHODS: Patients with SNV were successively included in a longitudinal study assessing MCVEs and other sequelae. Dual x-ray absorptiometry was performed to evaluate abdominal adipose tissue. Patients were prospectively followed for MCVEs, defined as myocardial infarction, unstable angina, stroke, arterial revascularisation and/or hospitalisation for or death from CV causes. RESULTS: One hundred and twenty consecutive SNV patients were included and analysed (54 males, mean age 53±18 years). High CV risk was found in 28 (23.3%) patients. In univariate analysis, age, male gender, VDI, VAT/SAT ratio and serum troponin level were significantly associated with high CV risk, whereas age and VAT/SAT ratio remained independently associated with high CV risk. Variables associated with high tertile of VAT/SAT ratio included age and metabolic risk factors. After median follow-up of 42 months, 19 (16%) patients experienced MCVEs. Hazard ratios for incident MCVEs compared with 1st tertile of VAT/SAT ratio were 7.22 (1.02-51.3; p=0.048) and 9.90 (3.15-31.2; p=0.0002) in the 2nd and 3rd tertile, respectively. CONCLUSIONS: Abdominal visceral adipose tissue is a reliable surrogate marker of CV risk and predicts incident MCVEs in SNV patients. Abdominal adipose tissue should be probably evaluated routinely in these patients to assess CV risk.

Current State of Precision Medicine in Primary Systemic Vasculitides.

Precision medicine (PM) is an emerging data-driven health care approach that integrates phenotypic, genomic, epigenetic, and environmental factors unique to an individual. The goal of PM is to facilitate diagnosis, predict effective therapy, and avoid adverse reactions specific for each patient. The forefront of PM is in oncology; nonetheless, it is developing in other fields of medicine, including rheumatology. Recent studies on elucidating the genetic architecture of polygenic and monogenic rheumatological diseases have made PM possible by enabling physicians to customize medical treatment through the incorporation of clinical features and genetic data. For complex inflammatory disorders, the prevailing paradigm is that disease susceptibility is due to additive effects of common reduced-penetrance gene variants and environmental factors. Efforts have been made to calculate cumulative genetic risk score (GRS) and to relate specific susceptibility alleles for use of target therapies. The discovery of rare patients with single-gene high-penetrance mutations informed our understanding of pathways driving systemic inflammation. Here, we review the advances in practicing PM in patients with primary systemic vasculitides (PSVs). We summarize recent genetic studies and discuss current knowledge on the contribution of epigenetic factors and extracellular vesicles (EVs) in disease progression and treatment response. Implementation of PM in PSVs is a developing field that will require analysis of a large cohort of patients to validate data from genomics, transcriptomics, metabolomics, proteomics, and epigenomics studies for accurate disease profiling. This multi-omics approach to study disease pathogeneses should ultimately provide a powerful tool for stratification of patients to receive tailored optimal therapies and for monitoring their disease activity.

Early obesity leads to increases in hepatic arginase I and related systemic changes in nitric oxide and l-arginine metabolism in mice

Obesity is a risk factor for vascular endothelial cell dysfunction characterized by low-grade, chronic inflammation. Increased levels of arginase I and concomitant decreases in l-arginine bioavailability are known to play a role in the pathogenesis of vascular endothelial cell dysfunction. In the present study, we focused on changes in the systemic expression of arginase I as well as l-arginine metabolism in the pre-disease state of early obesity prior to the onset of atherosclerosis. C57BL/6 mice were fed a control diet (CD; 10% fat) or high-fat diet (HFD; 60% fat) for 8 weeks. The mRNA expression of arginase I in the liver, adipose tissue, aorta, and muscle; protein expression of arginase I in the liver and plasma; and systemic levels of l-arginine bioavailability and NO2 − were assessed. HFD-fed mice showed early obesity without severe disease symptoms. Arginase I mRNA and protein expression levels in the liver were significantly higher in HFD-fed obese mice than in CD-fed mice. Arginase I levels were slightly increased, whereas l-arginine levels were significantly reduced, and these changes were followed by reductions in NO2 − levels. Furthermore, hepatic arginase I levels positively correlated with plasma arginase I levels and negatively correlated with l-arginine bioavailability in plasma. These results suggested that increases in the expression of hepatic arginase I and reductions in plasma l-arginine and NO2 − levels might lead to vascular endothelial dysfunction in the pre-disease state of early obesity

Early obesity leads to increases in hepatic arginase I and related systemic changes in nitric oxide and L-arginine metabolism in mice.

Obesity is a risk factor for vascular endothelial cell dysfunction characterized by low-grade, chronic inflammation. Increased levels of arginase I and concomitant decreases in L-arginine bioavailability are known to play a role in the pathogenesis of vascular endothelial cell dysfunction. In the present study, we focused on changes in the systemic expression of arginase I as well as L-arginine metabolism in the pre-disease state of early obesity prior to the onset of atherosclerosis. C57BL/6 mice were fed a control diet (CD; 10% fat) or high-fat diet (HFD; 60% fat) for 8 weeks. The mRNA expression of arginase I in the liver, adipose tissue, aorta, and muscle; protein expression of arginase I in the liver and plasma; and systemic levels of L-arginine bioavailability and NO2- were assessed. HFD-fed mice showed early obesity without severe disease symptoms. Arginase I mRNA and protein expression levels in the liver were significantly higher in HFD-fed obese mice than in CD-fed mice. Arginase I levels were slightly increased, whereas L-arginine levels were significantly reduced, and these changes were followed by reductions in NO2- levels. Furthermore, hepatic arginase I levels positively correlated with plasma arginase I levels and negatively correlated with L-arginine bioavailability in plasma. These results suggested that increases in the expression of hepatic arginase I and reductions in plasma L-arginine and NO2- levels might lead to vascular endothelial dysfunction in the pre-disease state of early obesity.

Identification of potential gene targets in systemic vasculitis using DNA microarray analysis.

The present study aimed to identify the involvement of critical genes in systemic vasculitis, to gain an improved understanding of the molecular circuity and to investigate novel potential gene targets for systemic vasculitis treatment. The dual­color cDNA microarray data of GSE16945, consisting of peripheral mononuclear blood cell specimens from 13 patients with systemic vasculitis and 16 healthy controls, was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened in systemic vasculitis compared with controls using BRB ArrayTools, followed by the construction of a protein­protein interaction (PPI) network using the clusterProfiler package, and significant functional interaction (FI) module selection. Furthermore, transcriptional factors (TFs) among the identified DEGs were predicted and a transcriptional regulation network was constructed. A total of 173 up- and 93 downregulated genes were identified, which were mainly associated with immune response pathways. FBJ murine osteosarcoma viral oncogene homolog (FOS), ubiquitin B (UBB), signal transducer and activator of transcription 1 (STAT1) and MX dynamin­like GTPase 1 (MX1) were identified as hub proteins in the PPI network. Furthermore, UBB, FOS, and STAT1 were hub proteins in the three identified FI modules, respectively. In total, nine TFs were predicted among the DEGs. Of the DEGs that were predicted to be TFs, STAT1, v­maf avian musculoaponeurotic fibrosarcoma oncogene homolog B (MAFB) and tyrosine 3­monooxygenase/tryptophan 5­monooxygenase activation protein Z (YWHAZ), which interacted with each other, were identified to regulate further DEGs as target genes. Various genes, including FOS, UBB, MX1, STAT1, MAFB, and YWHAZ may be potential targets useful for the treatment of systemic vasculitis.

Epigenomic functional characterization of genetic susceptibility variants in systemic vasculitis.

Systemic vasculitides are poorly understood inflammatory diseases of the blood vessels that are frequently associated with significant organ damage. Genetic risk variants contribute to the susceptibility of vasculitis, but functional consequences of these genetic variants are largely unknown. Most genetic risk variants in immune-mediated diseases, including systemic vasculitis, are localized to non-coding genetic regions suggesting they might increase disease risk by influencing regulatory elements within the genome. Long range regulatory interactions pose an additional obstacle in localizing functional consequences associated with risk variants to specific genes or cell types. We used cell-type specific enrichment patterns of histone changes that mark poised, primed, and active enhancers, and DNase hypersensitivity to identify specific immune cells mediating genetic risk in vasculitis. Our data suggest that genetic risk variants in ANCA-associated vasculitis are significantly enriched in enhancer elements in Th17 cells, supporting a role for Th17 cells in this disease. Primed and active enhancer elements in B cells can be potentially affected by genetic risk variants associated with Kawasaki disease. Genetic risk in Behçet's disease and Takayasu arteritis might affect enhancer elements in multiple cell types, possibly explained by influencing enhancers in hematopoietic stem cells. Interestingly, our analyses indicate a role for B cells in Kawasaki disease, Behçet's disease, and Takayasu arteritis, and suggest that further work to characterize the involvement of B cells in these diseases is warranted.

Clinical effect of white matter network disruption related to amyloid and small vessel disease.

BACKGROUND: We tested our hypothesis that the white matter network might mediate the effect of amyloid and small vessel disease (SVD) on cortical thickness and/or cognition. METHODS: We prospectively recruited 232 patients with cognitive impairment. Amyloid was assessed using Pittsburgh compound B-PET. SVD was quantified as white matter hyperintensity volume and lacune number. The regional white matter network connectivity was measured as regional nodal efficiency by applying graph theoretical analysis to diffusion tensor imaging data. We measured cortical thickness and performed neuropsychological tests. RESULTS: SVD burden was associated with decreased nodal efficiency in the bilateral frontal, lateral temporal, lateral parietal, and occipital regions. Path analyses showed that the frontal nodal efficiency mediated the effect of SVD on the frontal atrophy and frontal-executive dysfunction. The temporoparietal nodal efficiency mediated the effect of SVD on the temporoparietal atrophy and memory dysfunction. However, Pittsburgh compound B retention ratio affected cortical atrophy and cognitive impairment without being mediated by nodal efficiency. CONCLUSIONS: We suggest that a disrupted white matter network mediates the effect of SVD, but not amyloid, on specific patterns of cortical atrophy and/or cognitive impairment. Therefore, our findings provide insight to better understand how amyloid and SVD burden can give rise to brain atrophy or cognitive impairment in specific patterns.

Disease assessment in systemic vasculitis.

The anti-neutrophil cytoplasm antibody-associated vasculitides are complex multi-system disorders with many overlapping clinical features. Their outcome has been transformed by effective immunosuppression, preventing death in over 70% of cases. The quality of survival is affected by the disease course, which is characterized by a significant likelihood of relapse in 38%, chronic effects from the disease and its treatment, as well as emerging or worsening comorbidity, all of which contribute to the patient's clinical condition and outcome. Whilst imaging and laboratory testing including histology are important aspects of diagnosis, they are of limited value in assessing response to therapy or subsequent disease course. We have developed standardized validated clinical methods to quantify disease activity and damage; we are developing effective measures of patient experience to complement these procedures. This approach provides a rational basis for clinical management as well as being essential in the conduct of clinical trials and studies in vasculitis, by providing reproducible definitions of relapse, remission and response to therapy for patients with systemic vasculitis. Clinical assessment remains the current gold standard for evaluating disease progress, but requires regular training to ensure standardization. The development of biomarkers in future may produce a more accurate description of disease and identify potential targets for therapy as well as predictors of response to drugs.

Plasma nitrite is an indicator of acute changes in ambient air pollutant concentrations.

CONTEXT: Endothelial dysfunction has been suggested as a potential mechanism by which ambient air pollution may cause acute cardiovascular events. Recently, plasma nitrite has been developed as a marker of endothelial dysfunction. OBJECTIVES: We examined the changes in plasma nitrite concentration associated with increases in ambient air pollutant concentrations in the previous 7 d. MATERIALS AND METHODS: We linked up to three measurements of plasma nitrite concentrations obtained from 49 students to 24-h average concentrations of five criteria air pollutants [particle mass < 2.5 µm in aerodynamic diameter (PM(2.5)), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3)] measured at two monitoring sites closest to Rutgers University campus (6-15 miles) in New Jersey during the years 2006-2009. We examined the change in plasma nitrite associated with each interquartile-range (IQR) increase in pollutant concentration in the previous 24 h and six preceding 24- h periods, using linear mixed models. RESULTS: IQR increases in mean PM(2.5) (7.0 µg/m³) and CO (161.7 parts per billion) concentrations in the first 24 h before the plasma nitrite measurement were associated with increased plasma nitrite concentrations (PM(2.5): 15.5 nanomolar; 95% confidence interval (CI): 2.4, 28.5; CO: 15.6 nanomolar; 95% CI: 2.4, 28.9). Increased plasma nitrite associated with IQR increases in O3 and SO2 concentrations over longer lags were observed. DISCUSSION AND CONCLUSION: Rapid increases in plasma nitrite following exposure to ambient air pollutants support the hypothesis that ambient air pollution is associated with inducible nitric oxide synthase-mediated systemic inflammation in humans.

High-mobility group box 1 (HMGB1) in childhood: from bench to bedside.

UNLABELLED: High-mobility group box protein 1 (HMGB1) is a nonhistone nuclear protein that has a dual function. Inside the cell, HMGB1 binds DNA, regulating transcription and determining chromosomal architecture. Outside the cell, HMGB1 activates the innate system and mediates a wide range of physiological and pathological responses. HMGB1 exerts these actions through differential engagement of multiple surface receptors, including Toll-like receptor (TLR)2, TLR4, and receptor for advanced glycation end products (RAGE). HMGB1 is implicated as a late mediator of sepsis and is also involved in inflammatory and autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Interestingly, HMGB1 was associated with tumor progression, becoming a potential therapeutic target, due to its involvement in the resistance to chemotherapy. Its implication on the pathogenesis of systemic vasculitis and inflammatory bowel diseases has also been evaluated. Moreover, it regulates neuroinflammation after traumatic brain injuries or cerebral infectious diseases. The aim of this review is to analyze these different roles of HMGB1, both in physiological and pathological conditions, discussing clinical and scientific implications in the field of pediatrics. CONCLUSION: HMGB1 plays a key role in several pediatric diseases, opening new scenarios for diagnostic biomarkers and therapeutic strategies development.

Anti-TNF-alpha therapy and systemic vasculitis.

TNF-α is a pleiotropic cytokine, which plays a major role in the pathogenesis of numerous autoimmune and/or inflammatory systemic diseases. Systemic vasculitis constitutes a group of rare diseases, characterized by inflammation of the arterial or venous vessel wall, causing stenosis and thrombosis. Treatment of the different type of vasculitis mainly relies on steroids and immunosuppressive drugs. In case of refractory or relapsing diseases, however, a second line of treatment may be required. Anti-TNF-α drugs have been used in this setting during the last 15 years with inconsistent results. We reviewed herein the use of anti-TNF-α therapy in different kind of vasculitis and concluded that, except for Behcet's disease, this therapeutic option has not demonstrated significant improvement in the treatment of vasculitis.

[System of microcirculation, markers of vascular wall damage and systematicity of the process in rheumatic diseases].

The work was aimed at studying the interrelationship of the microcirculation system and the parameters of endothelial activation with markers of inflammatory process activity in rheumatic diseases (RD). We carried out a comprehensive examination of a total of 330 patients presenting with systemic diseases of connective tissue (SDCT), rheumatoid arthritis (RA) and systemic vasculitis (SV). Studying microcirculation included impregnation of filmy preparations according to the V.V. Kupriyanov technique and biomicroscopy of the conjunctiva of the eyeball. We also determined markers of endothelial activation and lesion of vascular wall, indices of activity of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and vasculitis clinical activity index (VCAI), common carotid artery intima-media thickness (CCA-IMT), biopsy materials of the musculocutaneous flap, of the operational and autopsy materials. Determining the indices of microcirculation showed that first of all the process involves postcapillaries and venules which are dilated, becoming tortuous, with the formation of microaneurysms and stellate venules. Capillaries, postcapillaries and venules were found to contain parietally located small-grained conglomerates of blood platelets and thrombocytic masses plugging up the lumens of microvessels. Intravascular alterations were characterized by the presence of erythrocyte aggregates, stases, microthrombovasculitis, «sludge¼ phenomenon, and a decrease in capillary blood flow. Extravascular changes included perivascular haemorrhages. In arterioles and precapillaries the inflammatory process manifested itself by swelling, dystrophy and desquamation of endothelial cells, plasmatic impregnation of the walls, luminal thrombosis followed by the development of severe sclerosis and glialinosis. The morphological study showed the presence of destructive alterations in the vascular wall, fibrinoid necrosis, and infiltration-proliferative cellular reaction. The most pronounced changes in the autoimmune inflammation markers had place in RA and systemic lupus erythematosus (SLE). We revealed increased indices of inflammatory process activity such as interleukin-8, C-reactive protein (CRP). We also revealed the signs of endothelial dysfunction, manifesting itself as a statistically significant (p<0.01) increase in concentrations of the soluble vascular cell adhesion molecule (sVCAM-1), von Willebrand factor antigen (VWFA), the number of desquamated endotheliocytes (DE). Also observed was a clear-cut dependence of the level of endothelial activation markers from the degree of the processes activity. We revealed a positive correlation between the level of CRP, IgG RF, the level of sVCAM-1 and the number of DE. The levels of interleukin-8, sVCAM-1 and VWFA were elevated in patients with RD. Increased activity of the disease was accompanied by impairments at the level of the microcirculatory bed, an increase in the concentration of inflammation markers and indices of endothelial dysfunction.

Leptin-induced endothelial dysfunction: a target for therapeutic interventions.

Leptin has received much attention since its cloning in 1994. Initially, leptin research centered on satiety, energy balance and sympathetic activation. However, hyperleptinemia has since been identified as an independent risk factor for various cardiovascular pathologies including atherosclerotic coronary artery disease. Over the last decade, multiple studies have implicated leptin as an important mediator in endothelial dysfunction and neointimal hyperplasia, both key steps in the evolution of atherosclerotic vascular changes. Additionally, more recent evidence indicates that paracrine leptin release from perivascular adipose tissue (PVAT) has deleterious effects on the underlying endothelium and vascular smooth muscle cells (SMC), including the coronary circulation. This report reviews pertinent literature on leptin-mediated endothelial dysfunction, SMC proliferation and the role of PVAT-derived leptin with an emphasis on the coronary circulation and discussions of currently proposed molecular mechanisms of PVAT-mediated coronary endothelial dysfunction and neointimal hyperplasia.

Bone marrow examination for unexplained cytopenias reveals nonspecific findings in patients with collagen vascular disease.

CONTEXT: Collagen vascular diseases are frequently included in the differential diagnosis for unexplained cytopenias and often prompt a bone marrow biopsy in this patient population to exclude malignancy. Few large-scale studies have characterized the bone marrow morphology in patients with collagen vascular disease, and most are limited to systemic lupus erythematosus or rheumatoid arthritis. OBJECTIVE: To identify morphologic and immunohistochemical abnormalities specific to each of a wide range of collagen vascular disease cases. DESIGN: We examined 102 cases of collagen vascular disease and 38 controls and evaluated the complete blood count, peripheral blood morphology, bone marrow morphology, as well as immunohistochemical staining, for numerous cell lineages. RESULTS: Bone marrow findings, including abnormalities such as lymphoid aggregates, lipogranulomas, or abnormal localization of immature precursors, were not significantly different as compared to the control group. CONCLUSIONS: Bone marrow examination in patients with collagen vascular disease with cytopenias seldom provides new information. Caution should be exercised in interpreting morphologic findings suggestive of myelodysplasia since these are of a reactive nature in up to 27% of patients with collagen vascular disease. In a cost-effective diagnostic strategy, successful utilization may favor postponing a bone marrow biopsy while a more standardized autoimmune diagnostic panel is being performed.

Role and interactions of annexin A1 and oestrogens in the manifestation of sexual dimorphisms in cerebral and systemic inflammation.

BACKGROUND AND PURPOSE: Gender differences in inflammation are well described, with females often showing more robust, oestrogen-associated responses. Here, we investigated the influence of gender, oestrogen and the anti-inflammatory protein annexin A1 (AnxA1) on lipopolysaccharide (LPS)-induced leukocyte-endothelial cell interactions in murine cerebral and mesenteric microvascular beds. EXPERIMENTAL APPROACH: Intravital microscopy was used to visualize and quantify the effects of LPS (10 µg·per mouse i.p.) on leukocyte-endothelial interactions in male and female wild-type (WT) mice. The effects of ovariectomy ± oestrogen replacement were examined in WT and AnxA1-null (AnxA1(-/-) ) female mice. KEY RESULTS: LPS increased leukocyte adherence in the cerebral and mesenteric beds of both male and female WT mice; females showed exacerbated responses in the brain versus males, but not the mesentery. Ovariectomy further enhanced LPS-induced adhesion in the brain but not the mesentery; its effects were reversed by oestrogen treatment. OVX AnxA1(-/-) mice also showed exaggerated adhesive responses to LPS in the brain. However, these were unresponsive to ovariectomy and, paradoxically, responded to oestrogen with a pronounced increase in basal and LPS-induced leukocyte adhesion in the cerebrovasculature. CONCLUSIONS AND IMPLICATIONS: Our data confirm the fundamental role of AnxA1 in limiting the inflammatory response in the central and peripheral microvasculature. They also (i) show that oestrogen acts via an AnxA1-dependent mechanism to protect the cerebral, but not the mesenteric, vasculature from the damaging effects of LPS and (ii) reveal a paradoxical and potentially toxic effect of the steroid in potentiating the central response to LPS in the absence of AnxA1.

Endothelial injury and repair in systemic vasculitis of the young.

OBJECTIVE: Endothelial injury is central to the pathogenesis of vasculitis. The purpose of this study was to assess how indices of endothelial injury and repair change during different stages of disease activity in children with primary systemic vasculitis (PSV). METHODS: Fifty children with PSV, 17 children with nonvasculitic inflammatory diseases (pediatric inflammatory disease controls), 35 healthy age- and sex-matched pediatric controls, and 27 healthy adult controls were included in the study. Biomarkers examined were endothelial microparticles (EMPs), circulating endothelial cells (CECs), angiogenic growth factors, and endothelial progenitor cells (EPCs). EMP binding to annexin V, EMPs expressing CD144 or E-selectin, and EPCs expressing vascular endothelial growth factor receptor 2 (VEGFR-2), CD133, and CD34 were examined by flow cytometry. CECs were enumerated using immunomagnetic bead extraction techniques, and VEGF and angiopoietin 2 (Ang-2) were measured by enzyme-linked immunosorbent assay. RESULTS: Levels of CD144+ EMPs, CECs, VEGF, and EPCs were all significantly elevated in children with active vasculitis as compared with healthy children, and the levels declined with remission-inducing therapy in the individual patients. Treatment-naive patients with active disease had significantly higher levels of VEGF and Ang-2 than did those with active disease who were receiving treatment, although the levels of CECs and EMPs remained high in both of these groups. CONCLUSION: Elevation of the levels of CECs, EMPS, EPCs, VEGF, and Ang-2 occurs during active vasculitis in children. EPC responses to active vasculitis are different in children as compared with that observed in adults with vasculitis, and both CECs and EMPs can be used to monitor disease activity in children with vasculitis.