Vasculitis: determinants of disease patterns

Role of non-coding RNAs and exosomal non-coding RNAs in vasculitis: A narrative review

A category of very uncommon systemic inflammatory blood vessel illnesses known as vasculitides. The pathogenesis and etiology of vasculitis are still poorly known. Despite all of the progress made in understanding the genetics and causes behind vasculitis, there is still more to learn. Epigenetic dysregulation is a significant contributor to immune-mediated illnesses, and epigenetic aberrancies in vasculitis are becoming more widely acknowledged. Less than 2 % of the genome contains protein-encoding DNA. Studies have shown that a variety of RNAs originating from the non-coding genome exist. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) have attracted the most attention in recent years as they are becoming more and more important regulators of different biological processes, such as diseases of the veins. Extracellular vehicles (EVs) such as exosomes, are membrane-bound vesicular structures that break free either during programmed cell death, such as apoptosis, pyroptosis, and necroptosis or during cell activation. Exosomes may be involved in harmful ways in inflammation, procoagulation, autoimmune reactions, endothelial dysfunction/damage, intimal hyperplasia and angiogenesis, all of which may be significant in vasculitis. Herein, we summarized various non-coding RNAs that are involved in vasculitides pathogenesis. Moreover, we highlighted the role of exosomes in vasculitides.

Central and Peripheral Nervous System Complications of Vasculitis Syndromes from Pathology to Bedside: Part 2-Peripheral Nervous System

PURPOSE OF REVIEW

Peripheral nervous system vasculitides (PNSV) are a heterogeneous group of disorders with a clinical subset that may differ in prognosis and therapy. We provide a comprehensive update on the clinical assessment, diagnosis, complications, treatment, and follow-up of PNSV.

RECENT FINDINGS

Progress in neuroimaging, molecular testing, and peripheral nerve biopsy has improved clinical assessment and decision-making of PNSV, also providing novel insights on how to prevent misdiagnosis and increase diagnostic certainty. Advances in imaging techniques, allowing to clearly display the vessel walls, have also enhanced the possibility to differentiate inflammatory from non-inflammatory vascular lesions, while recent histopathology data have identified the main morphological criteria for more accurate diagnosis and differential diagnoses. Overall, the identification of peculiar morphological findings tends to improve diagnostic accuracy by defining a clearer boundary between systemic and non-systemic neuropathies. Therefore, the definition of epineurium vessel wall damage, type of vascular lesion, characterization of lymphocyte populations, antibodies, and inflammatory factors, as well as the identification of direct nerve damage or degeneration, are the common goals for pathologists and clinicians, who will both benefit for data integration and findings translation. Nevertheless, to date, treatment is still largely empiric and, in some cases, unsatisfactory, thus often precluding precise prognostic prediction. In this context, new diagnostic techniques and multidisciplinary management will be essential in the proper diagnosis and prompt management of PNSV, as highlighted in the present review. Thirty to fifty percent of all patients with vasculitis have signs of polyneuropathy. Neuropathies associated with systemic vasculitis are best managed according to the guidelines of the underlying disease because appropriate workup and initiation of treatment can reduce morbidity. Steroids, or in severe or progressive cases, cyclophosphamide pulse therapy is the standard therapy in non-systemic vasculitic neuropathies. Some patients need long-term immunosuppression. The use of novel technologies for high-throughput genotyping will permit to determine the genetic influence of related phenotypes in patients with PNSV.

The impact of the COVID-19 pandemic on patients with systemic vasculitis: a single-centre retrospective study

This study aimed to study the impact of the COVID-19 pandemic on patients living with systemic vasculitis in Kazakhstan. A single-centre retrospective study of the medical histories of 82 patients was carried out based on the regional clinical hospital of the city for all admissions with systemic vasculitis in the period from January 2019 to December 2021. The following qualitative (gender, disability, concomitant diseases) and quantitative (age, disease experience, laboratory data, etc.) variables were studied. To conduct the study, the criteria for the inclusion and exclusion of patients in the study were determined. According to the results of the study, there is a decrease in the number of hospitalized patients with vasculitis in the rheumatology department of the regional clinical hospital. Compared to 2019, in 2021, the number of hospitalized patients decreased by almost half (Table 1). Out of 82 cases, the most common was Takayasu disease (nonspecific aortoarteritis) (43.9%), IgA-vasculitis (Schenlein-Genoch disease) (31.71%), and they are typical mainly for females of rural origin, who were admitted to the hospital in a comorbid state (p < 0.001). 41.6% of patients have disabilities, and the majority of patients have a II disability group. The average body mass index is 24.2; 27 patients out of the total number of patients suffer from obesity. The most common clinical symptoms of patients with systemic vasculitis were injuries of the musculoskeletal system (75.6%). A negative average correlation was found between the indicators of the level of ESR and haemoglobin, the correlation coefficient is -0.535. The patients had concomitant diseases, such as diabetes mellitus, iron deficiency anaemia, coronary heart disease, hypertension, gastrointestinal tract diseases and hepatitis. Women of reproductive age from rural areas are often diagnosed with systemic vasculitis. A high rate of disability revealed among the patients can be explained by two main factors, the first is that the patients consulted the doctors untimely and the second is that the medical community are insufficiently informed about the management of autoimmune rheumatic diseases, in particular about systemic vasculitis, which hinders timely diagnosis and treatment, respectively. Patients, included in this survey, were mostly suffering from diseases of the musculoskeletal system, but depending on the type of vasculitis, other organs and systems may be affected. Table 1 Frequency of patients with systemic vasculitis over 3 years Year Frequency % p-value 2019 42 51.2 χ² = 12.463^a; p = 0.002 2020 23 28.0 2021 17 20.7 Total 82 100.0.

Endothelial Activation and Immune Thrombocytopenia: An Engagement Waiting for Consolidation

Immune thrombocytopenia (ITP) appears to be a heterogeneous disease. In some patients, autoimmunity may be associated with an inflammatory process, and in other patients, low platelets may interfere with other aspects of the coagulation system. Either may predispose to thrombosis or bleeding. Further investigation of the interactions of platelets, with inflammatory cytokines and endothelial biomarkers, may help us to better understand the disease, and to recognize those patients at risk of bleeding, or conversely thrombosis. The aim of this work is to estimate von Willebrand factor (vWF) and vascular cellular adhesion molecule (V-CAM) serum levels in adult immune thrombocytopenic patients (ITP) and to decipher their possible clinical correlates. Eighty adults (≥ 18 years) were enrolled in the study; naive newly diagnosed 40 patients with primary ITP (according to the ASH 2019) and 40 sex and age-matched healthy controls, all groups are subjected for complete blood count (CBC), liver, and renal function tests, ESR, CRP, V-CAM, and VWF-Ag by enzyme-linked immunosorbent assay (ELISA). There was a highly statistically significant difference between case and control as regards to the mean level of VWF-Ag and V-CAM. vWF and V-CAM could serve as biomarkers for endothelial alterations and should be investigated as a predictor of thrombocytopenic bleeding and tailor patient management accordingly.

Potential for novel imaging techniques to monitor early disease progression in connective tissue disease vasculopathy

Vasculopathy associated with connective tissue diseases (CTD) has diverse clinical presentations and complex underlying pathology. Existing imaging techniques remain inadequate for assessing vasculopathy in CTD, particularly in earlier stages of pathogenesis. Novel imaging techniques, such as optical coherence tomography, near-infrared spectroscopy and superb microvascular imaging, demonstrate potential in monitoring disease progression at earlier stages prior to systemic complications.

Classification of ANCA-associated vasculitis: differences based on ANCA specificity and clinicopathologic phenotype

The classification of vasculitis according to a schema with universal acceptance is challenging, given the heterogeneous and protean nature of these diseases. Formal nomenclature and classification criteria for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have suffered several changes since their first description; none provides comprehensive diagnostic and classification criteria. Different factors account for the difficulties in the classification of vasculitis, including the incomplete understanding of the pathogenesis, the multisystemic nature of the disease, the non-specific patterns of vascular involvement, the overlap between entities, and the presence of various classification systems. The present article reviews the classification of AAV considering different points of view, including clinical, serologic, pathogenetic, organ predilection, therapeutic, and prognostic factors, and provides perspectives on future challenges in the understanding of AAV. There is an unmet need for a unifying view of the disease spectrum that considers the constantly evolving paradigms.

Vasculitis and Breast Cancer: Mind the Hint

Diffuse alveolar haemorrhage related to an anti-neutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitis is an extremely rare form of presentation of breast cancer. Here we report the case of a 77-year-old woman with a histological diagnosis of a papillary ductal carcinoma of the breast presenting with a diffuse alveolar haemorrhage secondary to a perinuclear ANCA-associated vasculitis. To our knowledge, this is the first case ever reported of a diffuse alveolar haemorrhage related to an ANCA-associated small vessel vasculitis as a form of presentation of breast cancer. The therapeutic approach of this paraneoplastic vasculitis included the use of corticosteroids and plasmapheresis, a very useful technique to remove endothelial aggressors (circulating antibodies) as a strategy to earn time for a proper therapeutic decision specifically directed for disease modification, but that can also be associated with several severe adverse effects, which are illustrated in our case.

In Vitro Human Blood-Brain Barrier Model for Drug Permeability Testing

Blood-brain barrier (BBB), although very important for protection of brain from major neurotoxins, negatively affects the treatment of central nervous system diseases by limiting the passage of neuropharmaceuticals from blood to the brain. Thus, researchers have to investigate the passage of the produced drug molecules through the BBB before they are introduced to the market. Although these experiments have been traditionally performed on experimental animals, drug permeability tests are now carried out mostly by in vitro BBB models due to ethical problems, differences between species, and expensive and troublesome in vivo test procedures. In this method, we explain how to model and characterize a realistic in vitro BBB model using human derived cells and perform a drug permeability test using this model.

Peripheral inflammation and blood-brain barrier disruption: effects and mechanisms

The blood–brain barrier (BBB) is an important physiological barrier that separates the central nervous system (CNS) from the peripheral circulation, which contains inflammatory mediators and immune cells. The BBB regulates cellular and molecular exchange between the blood vessels and brain parenchyma. Normal functioning of the BBB is crucial for the homeostasis and proper function of the brain. It has been demonstrated that peripheral inflammation can disrupt the BBB by various pathways, resulting in different CNS diseases. Recently, clinical research also showed CNS complications following SARS‐CoV‐2 infection and chimeric antigen receptor (CAR)‐T cell therapy, which both lead to a cytokine storm in the circulation. Therefore, elucidation of the mechanisms underlying the BBB disruption induced by peripheral inflammation will provide an important basis for protecting the CNS in the context of exacerbated peripheral inflammatory diseases. In the present review, we first summarize the physiological properties of the BBB that makes the CNS an immune‐privileged organ. We then discuss the relevance of peripheral inflammation‐induced BBB disruption to various CNS diseases. Finally, we elaborate various factors and mechanisms of peripheral inflammation that disrupt the BBB.

Practical approach to vasculitides in adults: an overview of clinical conditions that can mimic vasculitides closely

Primary systemic vasculitides are rare diseases affecting blood vessel walls. The type and patterns of distribution of the organs affected usually reflect the size of the vessels predominantly involved, and the patterns of clinical manifestations are generally useful to reach a specific diagnosis. However, presenting symptoms may lack adequate specificity for a prompt diagnosis, leading to a diagnostic (and therapeutic) delay, often causing irreversible damage to the affected organs. Due to their rarity and variable clinical presentation, the diagnosis of primary vasculitides could be challenging for physicians. Vasculitis mimickers, i.e. the clinical conditions that could be likely mistaken for vasculitides, need to be carefully ruled out, especially before starting the immunosuppressive therapy. We present here a practical approach to the diagnosis of primary systemic vasculitides involving large, medium and small size vessels, and reviewed most of the conditions that could mimic primary systemic vasculitides.

Update on vasculitis: an overview and dermatological clues for clinical and histopathological diagnosis - part I

The term vasculitis refers to the inflammation of vessel walls. It may range in severity from a self-limited disorder in one single organ to a life-threatening disease due to multiple organ failure. It has many causes, although they result in only a few histological patterns of vascular inflammation. Vessels of any type and in any organ can be affected, a fact that results in a broad variety of signs and symptoms. Different vasculitides with indistinguishable clinical presentations have quite different prognosis and treatments. This condition presents many challenges to physicians in terms of classification, diagnosis, appropriate laboratory workup, and treatment. Moreover, it compels a careful follow-up. This article reviews the Chapel-Hill 2012 classification, etiology, recent insights in pathophysiology, some important dermatological clues for the diagnosis and summarizes treatment of some of these complex vasculitis syndromes.

Aortic involvement in relapsing polychondritis: case-based review

Relapsing polychondritis is a systemic inflammatory disease that mainly affects ears, nose, eyes, joints, and large airway. Relapsing polychondritis may also affect cardiac valves and large vessels with the aorta being most frequently involved. We conducted a systematic literature review to delineate the clinical characteristics, treatment, and outcome of relapsing polychondritis patients with aortic involvement including thoracic and abdominal aorta, aortic valve, and coronary arteries. 113 patients reported in 85 manuscripts were retrieved through the systematic literature search and references of the selected manuscripts. With the addition of a patient from our center, a total of 114 patients were included in the analyses. Aortic vessel involvement was the predominant type of involvement that was identified in 93 (82%) patients, while aortic valve involvement was identified in 41 patients (36%). The median age at aortic involvement was 37 years [IQR: 30-53] with a delay of 5 years [IQR: 1-8] between first relapsing polychondritis symptom and aortic involvement. Nineteen percent of the patients were asymptomatic at the time of aortic involvement diagnosis. The initial treatment was immunosuppressives in 41 patients (56%) and surgery in 28 patients (38%). The mortality ratio was 27% in a 24 month follow-up [IQR: 7.5-54 months]. Aortic dissection or rupture was the most frequent causes of mortality. Concomitant coronary artery involvement suggested a worse outcome. Aortic involvement in relapsing polychondritis is a mortal complication despite medical and surgical treatments. It may be asymptomatic in 19% of the patients which warrants the importance of screening.

Mechanism and biomarkers in aortitis--a review

Aortitis can be the manifestation of an underlying infectious or noninfectious disease process. An autoimmune cause is suggested in a large proportion of noninfectious causes. Similar to other autoimmune diseases, the pathophysiology of aortitis has been investigated in detail, but the etiology remains unknown. Most cases of aortitis often go undetected for a long time and are often identified at late stages of the disease. Recent advances in imaging techniques have significantly improved the diagnosis of aortitis. However, significant challenges associated with the imaging techniques limit their use. Several routine inflammation-based markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and inflammatory cytokines, are nonspecific and, therefore, have limited use in the diagnosis of aortitis. The search for more specific serum biomarkers, which can facilitate detection and progression is under progress. Several autoantibodies have been identified, but assigning their role in the pathogenesis as well as their specificity remains a challenge. The current review addresses some of these issues in detail. KEY MESSAGES: • Noninfectious aortitis is an autoimmune disease. • Several biomarkers, including cytokines and autoantibodies, are increased in aortitis. • Imaging techniques, commonly used to detect aortitis, are associated with the high cost and technical challenges. • There is a need to develop low-cost biomarker-based detection tools. • The knowledge of biomarkers in aortitis detection is discussed.

Exploration of Novel Biomarkers in Vasculitis by Integrated Bioinfomatic Approaches

Angiitis, also known as vasculitis, is a chronic inflammatory disease characterized by the infiltration of inflammatory cells in surroundings of blood vessels, accompanied by vascular damage including fibrin deposition, collagen fiber degeneration, myocyte, and endotheliocyte necrosis. This work aimed to perform an integrated bioinformatic analysis of three data sets concerning vasculitis to explore and examine the potential diagnostic and therapeutic makers contributing to illuminating the pathomechanisms of vasculitis. We collected three sets of gene expression data designed by dual-channel method from Gene Expression Omnibus, which were based on the same platform (Agilent-014850 Whole Human Genome Microarray 4x44K G4112F). The meta-analysis was used to analyze the gene expression profiles and screen the differentially expressed genes followed by functional features identification. Subsequently, a protein-protein interaction and transcriptional regulation network were conducted for further investigation of expression mechanisms of vasculitis. Totally, 73 consistently upregulated genes, 49 consistently downregulated genes, and 26 genes with different expression directions were identified. Functional enrichment and transcription regulation analysis suggested upregulated genes (PPBP, PLAU, and HIST1H2BH) and downregulated genes such as IL23A gene were predominately associated with immune responses and cytokine receptors function. In addition, specific cancer-related genes such as MRVI1 was also extracted and considered as promising biomarkers of the development and progression of vasculitis. This study established an integrated meta-analysis approach and identified novel biomarkers involved in vasculitis, which further facilitate to explore and unravel the etiopathogenesis of vasculitis.

Extracellular vesicles in autoimmune vasculitis - Little dirts light the fire in blood vessels

Systemic vasculitis is diverse group of autoimmune disorders which are characterized by inflammation of blood vessel walls with deep aching and burning pain. Their underlying etiology and pathophysiology still remain poorly understood. Extracellular vesicles (EVs), including exosomes, microvesicles (MVs), and apoptotic bodies, are membrane vesicular structures that are released either during cell activation, or when cells undergo programmed cell death, including apoptosis, necroptosis, and pyroptosis. Although EVs were thought as cell dusts, but now they have been found to be potently active since they harbor bioactive molecules, such as proteins, lipids, nucleic acids, or multi-molecular complexes. EVs can serve as novel mediators for cell-to-cell communications by delivery bioactive molecules from their parental cells to the recipient cells. Earlier studies mainly focused on MVs budding from membrane surface. Recent studies demonstrated that EVs may also carry molecules from cytoplasm or even from nucleus of their parental cells, and these EVs may carry autoantigens and are important in vasculitis. EVs may play important roles in vasculitis through their potential pathogenic involvements in inflammation, autoimmune responses, procoagulation, endothelial dysfunction/damage, angiogenesis, and intimal hyperplasia. EVs have also been used as specific biomarkers for diagnostic use or disease severity monitoring. In this review, we have focused on the aspects of EV biology most relevant to the pathogenesis of vasculitis, discussed their perspective insights, and summarized the exist literature on EV relevant studies in vasculitis, therefore provides an integration of current knowledge regarding the novel role of EVs in systemic vasculitis.

Microbiomes of Inflammatory Thoracic Aortic Aneurysms Due to Giant Cell Arteritis and Clinically Isolated Aortitis Differ From Those of Non-Inflammatory Aneurysms

OBJECTIVE

We sought to characterize microbiomes of thoracic aortas from patients with non-infectious aortitis due to giant cell arteritis (GCA) and clinically isolated aortitis (CIA) and to compare them to non-inflammatory aorta aneurysm controls. We also compared microbiomes from concurrently processed and separately reported temporal arteries (TA) and aortas.

METHODS

From 220 prospectively enrolled patients undergoing surgery for thoracic aorta aneurysm, 49 were selected. Inflammatory and non-inflammatory cases were selected based on ability to match for age (+/-10 years), gender, and race. Biopsies were collected under aseptic conditions and snap-frozen. Taxonomic classification of bacterial sequences was performed to the genus level and relative abundances were calculated. Microbiome differential abundances were analyzed by principal coordinates analysis.

RESULTS

Forty-nine patients with thoracic aortic aneurysms (12 CIA, 14 GCA, 23 non-inflammatory aneurysms) were enrolled. Alpha (P=0.018) and beta (P=0.024) diversity differed between specimens from aortitis cases and controls. There were no significant differences between CIA and GCA (P>0.7). The largest differential abundances between non-infectious aortitis and non-inflammatory control samples included Enterobacteriaceae, Phascolarctobacterium, Acinetobactor, Klebsiella, and Prevotella. Functional metagenomic predictions with PICRUSt revealed enrichment of oxidative phosphorylation and porphyrin metabolism pathways and downregulation of transcription factor pathways in aortitis compared to controls. Microbiomes of aortic samples differed significantly from temporal artery samples from a companion study, in both control and GCA groups (P=0.0002).

CONCLUSION

Thoracic aorta aneurysms, far from being sterile, contain unique microbiomes that differ from those found in temporal arteries. The aorta microbiomes are most similar between aneurysms that were associated with inflammation, GCA, and CIA, but differed from those associated with non-inflammatory etiologies. These findings are promising in that they indicate that microbes may play a role in the pathogenesis of aortitis-associated aneurysms or non-inflammatory aneurysms by promoting or protecting against inflammation. However, we cannot rule out that these changes are related to alterations in tissue substrate that favor secondary changes in microbial communities.

A Review and Hypothesized Model of the Mechanisms That Underpin the Relationship Between Inflammation and Cognition in the Elderly

Age is associated with increased risk for several disorders including dementias, cardiovascular disease, atherosclerosis, obesity, and diabetes. Age is also associated with cognitive decline particularly in cognitive domains associated with memory and processing speed. With increasing life expectancies in many countries, the number of people experiencing age-associated cognitive impairment is increasing and therefore from both economic and social terms the amelioration or slowing of cognitive aging is an important target for future research. However, the biological causes of age associated cognitive decline are not yet, well understood. In the current review, we outline the role of inflammation in cognitive aging and describe the role of several inflammatory processes, including inflamm-aging, vascular inflammation, and neuroinflammation which have both direct effect on brain function and indirect effects on brain function via changes in cardiovascular function.

Endothelial activation and injury by microparticles in patients with systemic lupus erythematosus and rheumatoid arthritis

BACKGROUND

Endothelial activation and damage is commonly observed in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and is related to development of atherosclerosis and cardiovascular diseases. Different components of the immune system seem to participate in the endothelial injury, such as generation of autoantibodies and formation of immune complexes (ICs). Microparticles (MPs) and their immune complexes (MPs-ICs) are increased in the circulation of patients with SLE and RA; therefore, we propose these extracellular vesicles could interact and modulate the function of endothelial cells. Hence, the effect of MPs and MPs-ICs from patients with SLE and RA in endothelial cells was evaluated.

METHODS

Macrovascular and microvascular endothelial cells were exposed to MPs and MPs-ICs from healthy donors and patients with SLE and RA. Vesicles uptake/binding, expression of adhesion molecules, cytokine and chemokine production, monocyte adherence, and alterations of endothelial monolayer were evaluated by flow cytometry and fluorescence microscopy.

RESULTS

Endothelial cells internalized MPs and MPs-ICs and increased CD54 and CD102 expression and CCL2, CCL5, and IL-6 production after the treatment with these extracellular vesicles, which led to an increase in the adherence of classic monocytes. These vesicles also induced low expression of VE-cadherin in membrane, depolymerization of actin filaments, and formation of intercellular spaces, which led to endothelial death and increased permeability after MPs and MPs-ICs exposure.

CONCLUSIONS

MPs and MPs-ICs from patients with SLE and RA increase adhesion molecules expression, chemokine production, and structural alterations in macrovascular and microvascular endothelial cells. Therefore, high counts of these vesicles in patients would promote endothelial alterations and secondary tissue leukocyte infiltration.

Pulmonary vasculitis

Systemic vasculitides frequently affect the pulmonary vasculature. As the signs and symptoms of pulmonary vasculitis are variable and nonspecific, diagnosis and treatment represent a real challenge. Vasculitides should be given consideration, as these diseases present severe manifestations of rapidly progressing pulmonary disease. Examining other organs usually affected by vasculitides (e.g., the skin and kidneys) and determining autoantibody levels are essential to a better management of the disease. A radiological study would also contribute to establishing a diagnosis. The lungs are commonly involved in small-vessel vasculitis, anti-glomerular basement membrane disease, and vasculitides associated with antineutrophil cytoplasmic antibodies. Associated life-threatening diffuse alveolar haemorrhages and irreversible damage to other organs-usually the kidneys-are severe complications that require early diagnosis. Vasculitides are rare diseases that affect multiple organs. An increasing number of treatments-including biological agent-based therapies-requiring cooperation between specialists and centers have become available in the recent years. In the same way, clinicians should be familiar with the complications associated with immunosuppressive therapies.

An infant presenting with Kawasaki disease following immunization for influenza: A case report

Kawasaki disease (KD) is a childhood vascular disorder of unknown etiology. Concerns have recently been raised regarding vaccinations as a potential risk factor for KD. In addition, various forms of vasculitis have been reported as adverse events following administration after various vaccines. Patients exhibiting post vaccination KD have previously been described; however, thus far, to the best of our knowledge, only one patient exhibiting post influenza vaccination KD has been reported in Japan. The present study describes a case of KD 24 h after immunization with influenza in an infant (age, 18 months) following 6 days of high fever, a body rash that had persisted for 2 days and nonsuppurative bilateral conjunctivitis. To the best of the authors' knowledge, this is the first reported case in Korea and the present study reviews various recent studies regarding vasculitis following vaccination and the causal association between them.

Endothelial Progenitor Cells for the Vascularization of Engineered Tissues

Self-assembled microvasculature from cocultures of endothelial cells (ECs) and stromal cells has significantly advanced efforts to vascularize engineered tissues by enhancing perfusion rates in vivo and producing investigative platforms for microvascular morphogenesis in vitro. However, to clinically translate prevascularized constructs, the issue of EC source must be resolved. Endothelial progenitor cells (EPCs) can be noninvasively supplied from the recipient through adult peripheral and umbilical cord blood, as well as derived from induced pluripotent stem cells, alleviating antigenicity issues. EPCs can also differentiate into all tissue endothelium, and have demonstrated potential for therapeutic vascularization. Yet, EPCs are not the standard EC choice to vascularize tissue constructs in vitro. Possible reasons include unresolved issues with EPC identity and characterization, as well as uncertainty in the selection of coculture, scaffold, and culture media combinations that promote EPC microvessel formation. This review addresses these issues through a summary of EPC vascular biology and the effects of tissue engineering design parameters upon EPC microvessel formation. Also included are perspectives to integrate EPCs with emerging technologies to produce functional, organotypic vascularized tissues.

Why location matters - site-specific factors in rheumatic diseases

Rheumatic diseases follow a characteristic anatomical pattern of joint and organ involvement. This Review explores three interconnected mechanisms that might be involved in the predilection of specific joints for developing specific forms of arthritis: site-specific local cell types that drive disease; systemic triggers that affect local cell types; and site-specific exogenous factors, such as focal mechanical stress, that activate cells locally. The embryonic development of limbs and joints is also relevant to the propensity of certain joints to develop arthritis. Additionally, location-specific homeostasis and disease occurs in skin and blood vessels, thereby extending the concept of site-specificity in human diseases beyond rheumatology. Acknowledging the importance of site-specific parameters increases the complexity of current disease paradigms and brings us closer to understanding why particular disease processes manifest at a particular location.

The changing face of polyarteritis nodosa and necrotizing vasculitis

Polyarteritis nodosa (PAN) is a vasculitic disease characterized primarily by necrotizing vasculitis - inflammatory lesions in blood vessels that lead to vessel wall necrosis. Our understanding of PAN and necrotizing vasculitis has evolved over time. In addition to PAN, necrotizing vasculitis is now a recognized feature of a broad range of diseases with different aetiopathogenesis. For example, necrotizing vasculitis associated with hepatitis B virus infection has a different aetiopathogeneis to PAN and is now classified as a separate disease. Additionally, although 'classic' PAN is not an inherited disease, mutations in specific genes, such as ADA2 (also known as CECR1), can result in a necrotizing vasculopathy similar to PAN. The literature also suggests that the course of PAN differs in childhood-onset disease and in cases confined to the skin (so-called cutaneous PAN). Dissecting PAN and other autoinflammatory diseases with PAN-like features has enabled more-specific therapies and might also help us better understand the pathogenesis of these devastating conditions.

Endothelial Alterations in Systemic Lupus Erythematosus and Rheumatoid Arthritis: Potential Effect of Monocyte Interaction

Patients with systemic autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are prone to develop atherosclerosis and cardiovascular diseases five times more often than the general population; this increase in frequency could be partially explained by an increase in the macrovasculature endothelial damage. In these autoimmune diseases, a microvascular endothelial injury has also been reported in different organs and tissues, especially in sites where ultrafiltration processes occur. Different components that are characteristic to the immunopathology of RA and SLE could be involved in the endothelial cell activation, permeability increase, functional alteration, and vascular injury. Circulating immune complexes (IC) detected in SLE and RA have been proposed to participate in the endothelial injury. In the vascular environment, IC can generate different responses that could be mediated by monocytes, because these cells have patrolling and monitoring functions on the endothelium. However, with certain stimuli such as TLR ligands, the monocytes are retained in the lumen, releasing proinflammatory mediators that participate in the endothelial damage. This paper aims to review some aspects about the endothelial activation and dysfunction in the context of SLE and RA, as well as the potential role that monocytes apparently play in this process.

The cerebral circulation and cerebrovascular disease II: Pathogenesis of cerebrovascular disease

In this paper, we review the cerebral circulation and cerebrovascular disease (CVD) with an overview of the major types of CVD pathogenesis. These, as categorized here, are as follows: occlusive injury intrinsic to blood vessels, occlusive injury extrinsic to blood vessels, cerebral hypoperfusion, and cerebral hemorrhage. Following an overview of each of these categories, we conclude with a discussion of cerebral edema to illustrate how the pathological origins we covered can progress clinically. The content of this paper sets the stage for the detailed, clinically oriented discussion of stroke with which our series culminates in its subsequent Part III.

TYPES OF ANGIOPATHY IN EXPERIMENTAL AUTOIMMUNE DISEASE IN RATS

The purpose and objectives of this work were to study the nature of the heart, lungs and kidneys angiopathy in rats with a model of systemic autoimmune disease, carrying out comparisons of the results with extravasal morphological manifestations of the pathological process, the state of vascular endothelial function and activity of pro-inflammatory cytokines in the blood. The experiment was conducted on 40 non-linear rats. To simulate the disease animals were injected by complete Freund's adjuvant, a solution of splenic deoxyribonucleic acid cattle, mercaptopurine, methyluracilum and with food rats constantly received sulfate cadmium, lithium hydroxybutyrate and ammonium molybdate. Within two months from the start of the study animals were taken out of the experiment on the background of intraperitoneal nembutal anesthesia. Histological sections of the heart, lung and kidney tissue were stained with hematoxylin -eosin, alcian blue and by van-Gieson, becoming the PAS-reaction. In the animals with the proposed experimental model of systemic autoimmune disease observed morphological characteristics of lesions of the heart blood vessels, lungs and kidneys, the nature of the manifestations of which were interconnected with each other, which confirms the common pathogenetic angiopathy constructions at various diseases in clinical practice. In the genesis of cardiac, pulmonary and renal vessels lesions act the activation of pro-inflammatory cytokines and violation of vascular endothelial function, which has a certain practical significance. In clinical practice, not only purely systemic vasculitis, and other autoimmune diseases should be treated as angiopathy.

Vasculitides and the Complement System: a Comprehensive Review

Systemic vasculitides are a group of rare diseases characterized by inflammation of the arterial or venous vessel wall, causing stenosis or thrombosis. Clinical symptoms may be limited to skin or to other organs or may include multiple manifestations as systemic conditions. The pathogenesis is related to the presence of leukocytes in the vessels and to the IC deposition, which implies the activation of the complement system (CS) and then the swelling and damage of vessel mural structures. The complement system (CS) is involved in the pathogenesis of several autoimmune diseases, including systemic vasculitides. This enzymatic system is a part of the innate immune system, and its function is linked to the modulation of the adaptive immunity and in bridging innate and adaptive responses. Its activation is also critical for the development of natural antibodies and T cell response and for the regulation of autoreactive B cells. Complement triggering contributes to inflammation-driven tissue injury, which occurs during the ischemia/reperfusion processes, vasculitides, nephritis, arthritis, and many others diseases. In systemic vasculitides, a group of uncommon diseases characterized by blood vessel inflammation, the contribution of CS in the development of inflammatory damage has been demonstrated. Treatment is mainly based on clinical manifestations and severity of organ involvement. Evidences on the efficacy of traditional immunosuppressive therapies have been collected as well as data from clinical trials that involve the modulation of the CS. In particular in small-medium-vessel vasculitides, the CS represents an attractive target. Herein, we reviewed the pathogenetic role of CS in these systemic vasculitides as urticarial vasculitis, ANCA-associated vasculitides, anti-glomerular basement membrane disease, cryoglobulinaemic vasculitides, Henoch-Schönlein purpura/IgA nephropathy, and Kawasaki disease and therefore its potential therapeutic use in this context.

Microvesicles in Autoimmune Diseases

During apoptosis or activation, cells can release a subcellular structure, called a membrane microvesicle (also known as microparticle) into the extracellular environment. Microvesicles bud-off as a portion of cell membrane with its associated proteins and lipids surrounding a cytosolic core that contains intracellular proteins, lipids, and nucleic acids (DNA, RNA, siRNA, microRNA, lncRNA). Biologically active molecules on the microvesicle surface and encapsulated within can act on recipient cells as a novel mode of intercellular communication. Apoptosis has long been known to be involved in the development of diseases of autoimmunity. Abnormally persistent microvesicles, particularly apoptotic microvesicles, can accelerate autoimmune responses locally in specific organs and tissues as well as systemically. In this review, we focus on studies implicating microvesicles in the pathogenesis of autoimmune diseases and their complications.

Endothelial progenitor cells: Are they displaying a function in autoimmune disorders?

Endothelial Progenitor Cells (EPCs) are bone marrow derived cells able to differentiate in mature endothelial cells (EC) contributing to the generation of new vessels, connecting to fibronectin, and forming colonies and/or colony forming units. Since circulating EPCs can be actively considered part of endothelial damage in several cardiovascular diseases and autoimmune disorders the possibility to have a measure for endothelium damage should be considered of interest to predict the patient out-come. At the same time the EPCs proliferative and regenerative role could be considered for therapeutic applications. Studies have been performed to elucidate the role of EPCs in Systemic Sclerosis and many review and articles published on this topic. In the present paper we aimed to review the role of EPCs in other autoimmune disorders.

Spontaneous reports of vasculitis as an adverse event following immunization: A descriptive analysis across three international databases

BACKGROUND

Vasculitides have been reported as adverse events following immunization (AEFI) following various vaccines. We describe reports of vasculitis to three international spontaneous reporting systems.

METHODS

All spontaneous reports of vasculitis following immunization between January 2003 and June 2014 were retrieved from Eudravigilance (EV), the Vaccine Adverse Event Reporting System (VAERS), and VigiBase^®. A Standard MedDRA Query (SMQ) for vasculitis was used and vaccine types were categorized using the Anatomical Therapeutic Chemical classification system. We performed a descriptive analysis by source, sex, age, country, time to onset, vaccine, and type of vasculitis.

RESULTS

We retrieved 1797 reports of vasculitis in EV, 1171 in VAERS, and 2606 in VigiBase^®. Vasculitis was predominantly reported in children aged 1-17 years, and less frequently in the elderly (>65 years). The generic term "vasculitis" was the most frequently reported AEFI in this category across the three databases (range 21.9% to 27.5% of all reported vasculitis for vaccines). For the more specific terms, Henoch-Schoenlein Purpura (HSP) was most frequently reported, (19.1% on average), followed by Kawasaki disease (KD) (16.1% on average) and polymyalgia rheumatica (PMR) (9.2% on average). Less frequently reported subtypes were cutaneous vasculitis (CuV), vasculitis of the central nervous system (CNS-V), and Behcet's syndrome (BS). HSP, PMR and CuV were more frequently reported with influenza vaccines: on average in 29.3% for HSP reports, 61.5% for PMR reports and in 39.2% for CuV reports. KD was reported with pneumococcal vaccines in 32.0% of KD reports and with rotavirus vaccines in more than 20% of KD reports. BS was most frequently reported after hepatitis and HPV vaccines and CNS-V after HPV vaccines.

CONCLUSION

Similar reporting patterns of vasculitides were observed in different databases. Implementation of standardized case definitions for specific vasculitides could improve overall data quality and comparability of reports.

Vasculitis as an adverse event following immunization - Systematic literature review

BACKGROUND

Several types of vasculitis have been observed and reported in temporal association with the administration of various vaccines. A systematic review of current evidence is lacking.

OBJECTIVE

This systematic literature review aimed to assess available evidence and current reporting practice of vasculitides as adverse events following immunization (AEFI).

METHODS

We reviewed the literature from 1st January 1994 to 30th June 2014. This review comprises randomized controlled trials, observational studies, case series, case reports, reviews and comments regardless of vaccine and target population.

RESULTS

The initial search resulted in the identification of 6656 articles. Of these, 157 articles were assessed for eligibility and 75 studies were considered for analysis, including 6 retrospective/observational studies, 2 randomized controlled trials, 7 reviews, 11 case series, 46 case reports and 3 comments. Most of the larger, higher quality studies found no causal association between vaccination and subsequent development of vasculitis, including several studies on Kawasaki disease and Henoch-Schönlein purpura (IgA vasculitis). Smaller case series reported a few cases of vasculitis following BCG and vaccines against influenza and hepatitis. Only 24% of the articles reported using a case definition of vasculitis.

CONCLUSIONS

Existing literature does not allow establishing a causative link between vaccination and vasculitides. Further investigations were strengthened by the use of standardized case definitions and methods for data collection, analysis and presentation to improve data comparability and interpretation of vasculitis cases following immunization.

Kawasaki disease

Kawasaki disease (KD) is the archetypal pediatric vasculitis, exemplifying the unique aspects and challenges of vascular inflammation in children. The condition is almost unheard of in adults, is closely associated with infections, and is self-limited, with fever resolving after an average of 12 days even without treatment. Yet KD is also a potentially fatal disease and the most common cause of acquired heart disease in the developed world. Unraveling of the developmental, immunologic, and genetic secrets of Kawasaki disease promises to improve our understanding of vasculitis in particular, and perhaps also to provide a window on the fundamental mysteries of inflammatory diseases in general.

Histologic and clinical features of primary and secondary vasculitis

Inflammation of the blood vessel wall has been reported infrequently in dogs, and it may occur without apparent cause (primary vasculitis) or as a pathologic reaction to a range of initiating insults (secondary vasculitis). The aims of our study were to report histologic, clinical, and survival data from a large series of cases with primary and secondary vasculitis, and to compare the clinical parameters and outcome data between groups. Clinical data was collected retrospectively from the medical records of 42 client-owned dogs with a histologic diagnosis of primary or secondary vasculitis, and follow-up information was obtained. Cases were grouped according to clinical and histologic descriptors, and biochemical, hematologic, and survival data was compared between groups. Several forms of primary vasculitis were observed, and vascular inflammation was observed in conjunction with numerous other diseases. Female dogs were more likely to develop primary vasculitis, and serum globulin concentration was greater in dogs with primary vasculitis compared to those with underlying disease. All dogs with primary vasculitis of the central nervous system died or were euthanized shortly after presentation, but other forms of primary vasculitis could be managed effectively. In conclusion, presentation of clinical cases in this series was variable, and there did not appear to be well-defined vasculitic syndromes as described in people.

Current concept and epidemiology of systemic vasculitides

Although a new classification algorithm for systemic vasculitides was proposed by Watts et al. and the Chapel Hill Consensus Conference (CHCC) was updated in 2012, there are currently no validated diagnostic criteria for systemic vasculitides. The Diagnostic and Classification Criteria for Vasculitis study (DCVAS) is a global study to develop and improve the diagnostic criteria for systemic vasculitides. The epidemiology of systemic vasculitides differs widely among countries. For example, in the case of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, patients with microscopic polyangiitis (MPA) and with positivity for MPO-ANCA are predominant in Asian countries, whereas patients with granulomatosis with polyangiitis (GPA) and with positivity for PR3-ANCA are predominant in northern Europe and the United States. Interstitial lung disease (ILD) occurs more frequently in Asian patients compared with patients in Europe. The incidence and the prevalence of large-vessel vasculitis also differ significantly. Giant cell arteritis (GCA) occurs frequently in northern Europe, unlike Takayasu arteritis (TAK). The ethnic and regional differences in the incidence, prevalence and clinical characteristics of patients with vasculitis should be recognized when we diagnose and treat patients with vasculitis using criteria, and should also be considered when interpreting the results from clinical studies.