Mechanisms of Endothelial Dysfunction in Antiphospholipid Syndrome: Association With Clinical Manifestations

A Genome-Wide Association Study Suggests New Susceptibility Loci for Primary Antiphospholipid Syndrome

OBJECTIVE

Primary antiphospholipid syndrome (PAPS) is a rare autoimmune disease characterized by the presence of antiphospholipid antibodies and the occurrence of thrombotic events and pregnancy complications. Our study aimed to identify novel genetic susceptibility loci associated with PAPS.

METHODS

We performed a genome-wide association study comprising 5,485 individuals (482 affected individuals) of European ancestry. Significant and suggestive independent variants from a meta-analysis of approximately 7 million variants were evaluated for functional and biological process enrichment. The genetic risk variability for PAPS in different populations was also assessed. Hierarchical clustering, Mahalanobis distance, and Dirichlet Process Mixtures with uncertainty clustering methods were used to assess genetic similarities between PAPS and other immune-mediated diseases.

RESULTS

We revealed genetic associations with PAPS in a regulatory locus within the HLA class II region near HLA-DRA and in STAT1-STAT4 with a genome-wide level of significance; 34 additional suggestive genetic susceptibility loci for PAPS were also identified. The disease risk allele near HLA-DRA is associated with overexpression of HLA-DRB6, HLA-DRB9, HLA-DQA2, and HLA-DQB2 in immune cells, vascular tissue, and nervous tissue. This association is independent of the association between PAPS and HLA-DRB1*1302. Functional analyses highlighted immune-related pathways in PAPS-associated loci. The comparison with other immune-mediated diseases revealed a close genetic relatedness to neuromyelitis optica, systemic sclerosis, and Sjögren syndrome, suggesting co-localized causal variations close to STAT1-STAT4, TNPO3, and BLK.

CONCLUSION

This study represents a comprehensive large-scale genetic analysis for PAPS and provides new insights into the genetic basis and pathophysiology of this rare disease.

Antiphospholipid Syndrome and Catastrophic Antiphospholipid Syndrome: A Comprehensive Review of Pathogenesis, Clinical Features, and Management Strategies

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the presence of antiphospholipid antibodies (aPLs) that predispose individuals to thrombotic events and pregnancy-related complications. APS can occur as a primary condition or in association with other autoimmune diseases, most commonly systemic lupus erythematosus (SLE). Catastrophic APS (CAPS) is a rare, severe variant of APS, marked by rapid-onset, widespread thrombosis leading to multi-organ failure, often triggered by infections, surgical procedures, or cessation of anticoagulation therapy. Both APS and CAPS present significant clinical challenges due to their potential for severe morbidity and mortality. This comprehensive review aims to provide a detailed overview of the pathogenesis, clinical features, diagnostic criteria, and management strategies for APS and CAPS. The review highlights the immunological mechanisms underlying APS, including the role of aPLs, complement system activation, and endothelial cell dysfunction in developing thrombosis. It also outlines the clinical manifestations of APS, such as venous and arterial thrombosis, pregnancy morbidity, and neurological symptoms, along with the diagnostic criteria based on clinical and laboratory findings. The review delves into its pathogenesis, clinical presentation, and diagnostic challenges in the context of CAPS, emphasizing the need for immediate and intensive therapy to manage this life-threatening condition. Current management strategies for APS, including anticoagulant therapy, immunomodulatory treatments, and specific interventions for pregnancy-related complications, are discussed. The review highlights the importance of a multidisciplinary approach for CAPS, combining anticoagulation, high-dose corticosteroids, plasma exchange, and intravenous immunoglobulin. The review also addresses the prognosis and long-term outcomes for patients with APS and CAPS, underlining the necessity for ongoing monitoring and follow-up to prevent recurrent thrombotic events and manage chronic complications. Finally, future directions in research are explored, focusing on emerging therapies, biomarkers for early diagnosis, and the need for clinical trials to advance the understanding and treatment of these complex syndromes. By enhancing the understanding of APS and CAPS, this review aims to improve diagnosis, treatment, and patient care, ultimately leading to better health outcomes for those affected by these conditions.

Interaction of antiphospholipid antibodies with endothelial cells in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease with arteriovenous thrombosis and recurrent miscarriages as the main clinical manifestations. Due to the complexity of its mechanisms and the diversity of its manifestations, its diagnosis and treatment remain challenging issues. Antiphospholipid antibodies (aPL) not only serve as crucial "biomarkers" in diagnosing APS but also act as the "culprits" of the disease. Endothelial cells (ECs), as one of the core target cells of aPL, bridge the gap between the molecular level of these antibodies and the tissue and organ level of pathological changes. A more in-depth exploration of the relationship between ECs and the pathogenesis of APS holds the potential for significant advancements in the precise diagnosis, classification, and therapy of APS. Many researchers have highlighted the vital involvement of ECs in APS and the underlying mechanisms governing their functionality. Through extensive in vitro and in vivo experiments, they have identified multiple aPL receptors on the EC membrane and various intracellular pathways. This article furnishes a comprehensive overview and summary of these receptors and signaling pathways, offering prospective targets for APS therapy.

Crosstalk between Inflammation and Atherosclerosis in Rheumatoid Arthritis and Systemic Lupus Erythematosus: Is There a Common Basis?

Cardiovascular disease is the leading cause of morbidity and mortality in patients with rheumatoid arthritis and systemic lupus erythematosus. Traditional cardiovascular risk factors, although present in lupus and rheumatoid arthritis, do not explain such a high burden of early cardiovascular disease in the context of these systemic connective tissue diseases. Over the past few years, our understanding of the pathophysiology of atherosclerosis has changed from it being a lipid-centric to an inflammation-centric process. In this review, we examine the pathogenesis of atherosclerosis in systemic lupus erythematosus and rheumatoid arthritis, the two most common systemic connective tissue diseases, and consider them as emblematic models of the effect of chronic inflammation on the human body. We explore the roles of the inflammasome, cells of the innate and acquired immune system, neutrophils, macrophages, lymphocytes, chemokines and soluble pro-inflammatory cytokines in rheumatoid arthritis and systemic lupus erythematosus, and the roles of certain autoantigens and autoantibodies, such as oxidized low-density lipoprotein and beta2-glycoprotein, which may play a pathogenetic role in atherosclerosis progression.

Platelets and Thrombotic Antiphospholipid Syndrome

Antiphospholipid antibody syndrome (APS) is an autoimmune disorder characterised by thrombosis and the presence of antiphospholipid antibodies (aPL): lupus anticoagulant and/or IgG/IgM anti-β2-glycoprotein I and anticardiolipin antibodies. APS carries significant morbidity for a relatively young patient population from recurrent thrombosis in any vascular bed (arterial, venous, or microvascular), often despite current standard of care, which is anticoagulation with vitamin K antagonists (VKA). Platelets have established roles in thrombosis at any site, and platelet hyperreactivity is clearly demonstrated in the pathophysiology of APS. Together with excess thrombin generation, platelet activation and aggregation are the common end result of all the pathophysiological pathways leading to thrombosis in APS. However, antiplatelet therapies play little role in APS, reserved as a possible option of low dose aspirin in addition to VKA in arterial or refractory thrombosis. This review outlines the current evidence and mechanisms for excessive platelet activation in APS, how it plays a central role in APS-related thrombosis, what evidence for antiplatelets is available in clinical outcomes studies, and potential future avenues to define how to target platelet hyperreactivity better with minimal impact on haemostasis.

Antiphospholipid Antibodies Associated with Native Arteriovenous Fistula Complications in Hemodialysis Patients: A Comprehensive Review of the Literature

Antiphospholipid antibody (aPL)-persistent positivity is frequent in hemodialysis (HD) patients. Native arteriovenous fistula (AVF) complications such as stenosis and thrombosis are among the most important causes of morbidity and mortality in hemodialysis patients. The association between aPL positivity and AVF thrombosis seems to now be well established. However, whether aPL positivity is associated with other AVF complications, such as maturation failure or stenosis, is not well known. Given the significant impact of AVF failure on patient's prognosis, it is of interest to further investigate this particular point in order to improve prevention, surveillance and treatment, and, ultimately, the patient's outcome. This literature review aims to report the recent literature on aPL-associated native AVF complications.

A genome-wide association study suggests new susceptibility loci for primary antiphospholipid syndrome

Objectives

Primary antiphospholipid syndrome (PAPS) is a rare autoimmune disease characterized by the presence of antiphospholipid antibodies and the occurrence of thrombotic events and pregnancy complications. Our study aimed to identify novel genetic susceptibility loci associated with PAPS.

Methods

We performed a genome-wide association study comprising 5,485 individuals (482 affected individuals) of European ancestry. Significant and suggestive independent variants from a meta-analysis of approximately 7 million variants were evaluated for functional and biological process enrichment. The genetic risk variability for PAPS in different populations was also assessed. Hierarchical clustering, Mahalanobis distance, and Dirichlet Process Mixtures with uncertainty clustering methods were used to assess genetic similarities between PAPS and other immune-mediated diseases.

Results

We revealed genetic associations with PAPS in a regulatory locus within the HLA class II region near HLA-DRA and in STAT4 with a genome-wide level of significance. 34 additional suggestive genetic susceptibility loci for PAPS were also identified. The disease risk allele in the HLA class II locus is associated with overexpression of HLA-DRB6 , HLA-DRB9 , HLA-DPB2 , HLA-DQA2 and HLA-DQB2 , and is independent of the association between PAPS and HLA-DRB1*1302 . Functional analyses highlighted immune and nervous system related pathways in PAPS-associated loci. The comparison with other immune-mediated diseases revealed a close genetic relatedness to neuromyelitis optica, systemic sclerosis, and Sjögren's syndrome, suggesting colocalized causal variations close to STAT4 , TNPO3 , and BLK .

Conclusions

This study represents a comprehensive large-scale genetic analysis for PAPS and provides new insights into the genetic basis and pathophysiology of this rare disease.

Stroke risk in multiple sclerosis: a critical appraisal of the literature

Observational studies suggest that the occurrence of stroke on multiple sclerosis (MS) patients is higher compared to the general population. MS is a heterogeneous disease that involves an interplay of genetic, environmental and immune factors. The occurrence of stroke is subject to a wide range of both modifiable and non-modifiable, short- and long-term risk factors. Both MS and stroke share common risk factors. The immune mechanisms that underlie stroke are similar to neurodegenerative diseases and are attributed to neuroinflammation. The inflammation in autoimmune diseases may, therefore, predispose to an increased risk for stroke or potentiate the effect of conventional stroke risk factors. There are, however, additional determinants that contribute to a higher risk and incidence of stroke in MS. Due to the challenges that are associated with their differential diagnosis, the objective is to present an overview of the factors that may contribute to increased susceptibility or occurrence of stroke in MSpatients by performing a review of the available to date literature. As both MS and stroke can individually detrimentally affect the quality of life of afflicted patients, the identification of factors that contribute to an increased risk for stroke in MS is crucial for the prompt implementation of preventative therapeutic measures to limit the additive burden that stroke imposes.

Comorbid association of obstructive sleep apnea (OSA) and thrombotic primary antiphospholipid syndrome (tPAPS): A more severe phenotype?

OBJECTIVE

We aimed to evaluate the frequency of obstructive sleep apnea (OSA) in patients with thrombotic primary antiphospholipid syndrome (tPAPS), to investigate the performance of screening tools for OSA in this scenario and to compare clinical/laboratorial differences in tPAPS patients with and without OSA.

METHODS

We consecutively enrolled patients with tPAPS to undergo sleep studies using a portable monitor. OSA was defined as apnea-hypopnea index ≥15 events/h. Frequency of OSA in tPAPS was evaluated and compared with age-, gender-, and BMI-matched controls (1:3 ratio) from the Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Next, we tested the performance of three different screening tools for assessing OSA in patients with tPAPS. Finally, patients with tPAPS were stratified according to OSA status comparing their clinical and laboratory characteristics (including damage burden measured by Damage Index for Antiphospholipid Syndrome [DIAPS] and biomarkers associated with thrombosis) using standard statistical procedures.

RESULTS

Fifty-two patients were included for analysis (females: 82.7%; mean age: 48 ± 14 years; body-mass index: 31.1 ± 6.5 Kg/m2; 25% with moderate-severe OSA). When compared to matched controls from ELSA-Brasil (n = 115), there was no significant differences in the frequencies of OSA (tPAPS: 12/42 [28.6%] vs. controls: 35/115 [30.4%], p = 0.821). Among screening tools, NoSAS had the highest area under ROC curve (AUC 0.806, CI 95% 0.672-0.939, p = 0.001), followed by STOP-Bang (AUC 0.772, CI 95% 0.607-0.938, p = 0.004). Patients with comorbid tPAPS and OSA presented higher levels of von Willebrand factor (vWF) (median 38.9 vs. 32.6, p = 0.038) and DIAPS (median 5 vs. 2, p = 0.020), when compared to those without OSA. OSA remained statistically associated with higher DIAPS, even after controlling for age, disease duration and BMI.

CONCLUSION

OSA is common in patients with tPAPS, with rates comparable to a non-referred population. Both NoSAS and STOP-Bang scores seems to be useful for screening OSA in these patients. Patients with tPAPS+OSA had higher damage burden and higher levels of vWF, which might suggest a more severe phenotype of tPAPS in this scenario.

The pathogenesis of obstetric APS: a 2023 update

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the persistent presence of antibodies directed against phospholipids and phospholipid-binding proteins that are associated with thrombosis and pregnancy-related morbidity. The latter includes fetal deaths, premature birth and maternal complications. In the early 1990s, a distinct set of autoantibodies, termed collectively antiphospholipid antibodies (aPL), were identified as the causative agents of this disorder. Subsequently histological analyses of the placenta from APS pregnancies revealed various abnormalities, including inflammation at maternal-fetal interface and poor placentation manifested by reduced trophoblast invasion and limited uterine spiral artery remodeling. Further preclinical investigations identified the molecular targets of aPL and the downstream intracellular pathways of key placental cell types. While these discoveries suggest potential therapeutics for this disorder, definitive clinical trials have not been completed. This concise review focuses on the recent developments in the field of basic and translational research pursuing novel mechanisms underlying obstetric APS.

Small-Extracellular-Vesicle-Derived miRNA Profile Identifies miR-483-3p and miR-326 as Regulators in the Pathogenesis of Antiphospholipid Syndrome (APS)

Primary antiphospholipid syndrome (PAPS) is a systemic autoimmune disease associated with recurrent thrombosis and/or obstetric morbidity with persistent antiphospholipid antibodies (aPL). Although these antibodies drive endothelial injury and thrombophilia, the underlying molecular mechanism is still unclear. Small extracellular vesicles (sEVs) contain miRNAs, key players in intercellular communication. To date, the effects of miRNA-derived sEVs in PAPS are not well understood. We characterised the quantity, cellular origin and miRNA profile of sEVs isolated from thrombotic APS patients (PAPS, n = 50), aPL-carrier patients (aPL, n = 30) and healthy donors (HD, n = 30). We found higher circulating sEVs mainly of activated platelet origin in PAPS and aPL patients compared to HD, that were highly engulfed by HUVECs and monocyte. Through miRNA-sequencing analysis, we identified miR-483-3p to be differentially upregulated in sEVs from patients with PAPS and aPL, and miR-326 to be downregulated only in PAPS sEVs. In vitro studies showed that miR-483-3p overexpression in endothelial cells induced an upregulation of the PI3K-AKT pathway that led to endothelial proliferation/dysfunction. MiR-326 downregulation induced NOTCH pathway activation in monocytes with the upregulation of NFKB1, tissue factor and cytokine production. These results provide evidence that miRNA-derived sEVs contribute to APS pathogenesis by producing endothelial cell proliferation, monocyte activation and adhesion/procoagulant factors.

Successful treatment of lupus anticoagulant hypoprothrombinemia syndrome with rituximab

Lupus anticoagulant-hypoprothrombinemia syndrome (LAHPS) is a rare acquired bleeding disorder secondary to development of antibodies against prothrombin protein, in the presence of antiphospholipid antibodies. We describe the case of a 13-year-old girl who presented with severe menorrhagia and symptomatic anemia. Labs indicated anemia, thrombocytopenia, elevated PT and aPTT, high-titer inhibitor on mixing studies, positive ANA and anti-dsDNA antibodies, along with a triple-positive antiphospholipid antibody panel. Given additional systemic manifestations, systemic lupus erythematosus was diagnosed. High dose steroids and hydroxychloroquine subsequently started. Her clinical course was complicated by femoral deep venous thrombosis and post renal biopsy retroperitoneal hematoma. Further workup revealed low prothrombin level and the diagnosis of lupus anticoagulant hypoprothrombinemia syndrome. In view of suboptimal response to initial immunosuppressive therapy, rituximab was added to her regimen, leading to an improvement in clinical symptoms and resolution of hypoprothrombinemia. She remains recurrence free 5 years from the event.

Antiphospholipid antibodies induce proinflammatory and procoagulant pathways in endothelial cells

Antiphospholipid syndrome (APS) is an autoimmune thrombophilia characterized by recurrent thrombotic events and/or pregnancy morbidity in the presence of antiphospholipid antibodies detected either as anti-cardiolipin, anti-β2 Glycoprotein I (anti-β2GPI) or Lupus anticoagulant (LA). Endothelial deregulation characterizes the syndrome. To address gene expression changes accompanying the development of autoimmune phenotype in endothelial cells in the context of APS, we performed transcriptomics analysis in Human Umbilical Vein Endothelial Cells (HUVECs) stimulated with IgG from APS patients and β2GPI, followed by intersection of RNA-seq data with published microarray and ChIP-seq results (Chromatin Immunoprecipitation). Our strategy revealed that during HUVEC activation diverse signaling pathways such as TNF-α, TGF-β, MAPK38, and Hippo are triggered as indicated by Gene Ontology (GO) classification and pathway analysis. Finally, cell biology approaches performed side-by-side in naïve and stimulated cultured HUVECs, as well as, in placenta specimens derived from Healthy donors (HDs) and APS-patients verified the evolution of an APS-characteristic gene expression program in endothelial cells during the initial stages of the disease's development.

Multimodality Cardiac Imaging in Patients with Systemic Lupus Erythematosus

Systemic lupus erythematous (SLE) is an autoimmune disease with a wide range of cardiovascular complications. The main manifestations include diseases of the coronary arteries, valves, pericardium, and myocardium. Multimodality cardiovascular imaging techniques are critical for evaluating the extent of cardiac manifestations in SLE patients, which can provide valuable prognostic information. However, their utility has previously not been well defined. This review provides a state-of-the-art update on the cardiovascular manifestations of lupus, as well as the role of multimodality cardiac imaging in guiding management of patients with SLE.

Tissue factor in COVID-19-associated coagulopathy

Evidence of micro- and macro-thrombi in the arteries and veins of critically ill COVID-19 patients and in autopsies highlight the occurrence of COVID-19-associated coagulopathy (CAC). Clinical findings of critically ill COVID-19 patients point to various mechanisms for CAC; however, the definitive underlying cause is unclear. Multiple factors may contribute to the prothrombotic state in patients with COVID-19. Aberrant expression of tissue factor (TF), an initiator of the extrinsic coagulation pathway, leads to thrombotic complications during injury, inflammation, and infections. Clinical evidence suggests that TF-dependent coagulation activation likely plays a role in CAC. Multiple factors could trigger abnormal TF expression and coagulation activation in patients with severe COVID-19 infection. Proinflammatory cytokines that are highly elevated in COVID-19 (IL-1β, IL-6 and TNF-α) are known induce TF expression on leukocytes (e.g. monocytes, macrophages) and non-immune cells (e.g. endothelium, epithelium) in other conditions. Antiphospholipid antibodies, TF-positive extracellular vesicles, pattern recognition receptor (PRR) pathways and complement activation are all candidate factors that could trigger TF-dependent procoagulant activity. In addition, coagulation factors, such as thrombin, may further potentiate the induction of TF via protease-activated receptors on cells. In this systematic review, with other viral infections, we discuss potential mechanisms and cell-type-specific expressions of TF during SARS-CoV-2 infection and its role in the development of CAC.

Pregnancy Loss and Cardiovascular Diseases in Women: Recent Findings and Potential Mechanisms

PURPOSE OF REVIEW

Pregnancy loss (PL) has been acknowledged by the American Heart Association as a risk factor for cardiovascular diseases (CVD) later in life. This review aims to sum up recent findings (< ~ 5 years), concerning the link between PL and CVD.

RECENT FINDINGS

The association between PL and risk of CVD increased with increasing number of PLs and is inversely correlated to maternal age, indicating that the association concerns euploid PLs. Likely mechanisms leading to PL and an increased risk of CVD include endothelial dysfunction, a pro-inflammatory state, antiphospholipid syndrome, autoimmunity, and genetic predisposition. PL as an independent risk factor for CVD constitutes an obvious gateway for a more targeted approach to future research, prevention, and treatment. Future research should clarify the following questions to which the answers are still unknown: whether PL is (a) directly causing the increased risk of CVD or (b) sharing pathophysiological mechanisms also leading to CVD.

Differences in Antiphospholipid Antibody Profile between Patients with Obstetric and Thrombotic Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune condition characterised by the presence of antiphospholipid antibodies (aPL) associated with vascular thrombosis and/or pregnancy complications. In a cohort of 74 yet diagnosed APS individuals fulfilling Sydney laboratory criteria (twice positive for lupus anticoagulant, anticardiolipin, aCL, and/or anti-β2glycoprotein I, aβ2GPI), 33 out of 74 were obstetric APS (OAPS) and 41 thrombotic APS (TAPS) patients. 39% of TAPS patients were women. Although aPL detection was persistent, we observed an oscillatory aPL positivity in 56.7% and a transient seroconversion in 32.4% of APS patients at enrolment. Thus, we tested their sera in a line immunoassay that simultaneously detected IgG or IgM for criteria (aCL and aβ2GPI) and non-criteria (anti-phosphatidylserine, aPS; anti-phosphatidic acid, aPA; anti-phosphatidylinositol, aPI; anti-annexin 5, aA5; anti-prothrombin, aPT; anti-phosphatidylethanolamine; anti-phosphatidylglycerol, and anti-phosphatidylcholine) aPL. OAPS and TAPS patients displayed different but overlapping clusters based on their aPL reactivities. Specifically, while OAPS patients showed higher aPA, aPS, aA5, aβ2GPI and aPT IgM levels than TAPS patients, the latter displayed higher reactivity in aCL, aPI and aA5 IgG. Eventually, with a cut-off of the 99th percentile established from a population of 79 healthy donors, TAPS patients significantly tested more positive for aCL and aA5 IgG than OAPS patients, who tested more positive for aPA, aPS and aβ2GPI IgM. Transiently seronegative APS patients showed non-criteria aPL positivity twice in sera obtained 3 months apart. Overall, our data show that APS patients presented clusters of aPL that define different profiles between OAPS and TAPS, and persistent non-criteria aPL positivity was observed in those who are transiently seronegative.

Prevalence and coagulation correlation of anticardiolipin antibodies in patients with COVID-19

We aimed to determine prevalence and characteristics of anticardiolipin antibodies (ACLs) and its correlations with laboratory coagulation variables in patients with coronavirus disease 2019 (COVID-19). We retrospectively analyzed the prevalence of serum ACLs and its correlation with coagulative laboratory variables in 87 patients with COVID-19. ACLs were detected in 13/21 (61.91%) critically ill patients, and 21/66 (31.82%) in non-critically ill patients. For ACLs, IgA, and IgG were the most common types. The prevalence of IgG in critical ill patients was much higher than that in non-critical patients with odd ratio = 2.721. And the levels of all isotypes of ACLs in critically ill patients were much higher than those in non-critically ill patients. Correlation analysis showed that activated partial thromboplastin time and thrombin time had weak correlation with ACLs-IgG (R = 0.308, P = .031; R = 0.337, P = .018, respectively). Only the prevalence of ACLs-IgG shows a significant difference when compared critically ill patients with non-critically ill patients. ACLs do not seem to have a clear correlation with thrombosis occurred in COVID-19 patients.

Asymmetric Dimethylarginine Is a Marker of Endothelial Dysfunction in Thrombotic Antiphospholipid Syndrome Patients

Objective: The potential contribution of asymmetric dimethylarginine (ADMA) and high-sensitivity C reactive protein (hsCRP) to endothelial dysfunction in APS patients has not been studied in detail, until now. The study involved 105 APS patients (59 diagnosed with primary APS (PAPS) and 46 APS associated with systemic lupus erythematosus (SAPS)) who were compared to 40 controls. Endothelial dysfunction was assessed by measurement of flow-mediated dilatation (FMD) and glyceryl trinitrate dilatation (NMD) of the brachial artery. ADMA (micromol/L) was analyzed by ELISA. Results: FMD in patients with APS was significantly lower than that of the controls (p < 0.001), with no difference between the PAPS and the SAPS groups. ADMA and hsCRP concentrations were significantly higher in the patient cohort than in the control group (p < 0.001, p = 0.006, respectively), as was the case with the SAPS group as compared to the PAPS group (p < 0.001, p = 0.022, respectively). FMD impairment correlated to ADMA (ρ 0.472, p < 0.001) and to hsCRP (ρ 0.181, p = 0.033). In the regression model, the ADMA concentration confirmed the strength of its association (B 0.518, SE 0.183, Wald 8.041, p = 0.005, Exp(B) 1.679, 95% CI 1.174−2.402) to FMD impairment. The synergistic probability model of ADMA and hsCRP caused FMD impairment when the positivity of β2GPIIgG was added. ADMA may be used as a simple and low-cost tool for verifying the presence of endothelial dysfunction in APS patients. According to the results of the study, we could presume that hsCRP, together with aPL, has a preparatory effect on the endothelium in causing endothelial dysfunction.

Mammalian Target of Rapamycin Pathway Assessment in Antiphospholipid Antibody-Positive Patients with Livedo

OBJECTIVE

In antiphospholipid antibody (aPL) nephropathy, activation of the mammalian target of rapamycin (mTOR) contributes to endothelial cell proliferation, a key finding of aPL microvascular disease. Here, we examined mTOR activation in the skin of aPL-positive patients with livedo.

METHODS

Three patient groups with livedo were studied: (1) persistently aPL-positive with systemic lupus erythematosus (SLE); (2) persistently aPL-positive without SLE; and (3) aPL-negative SLE (control). After collecting aPL-related medical history, two 5-mm skin biopsies of livedo were performed on each patient: (1) peripheral (erythematous-violaceous lesion); and (2) central (nonviolaceous area). We stained specimens for phosphorylated protein kinase B (p-AKT) and phosphorylated S6 ribosomal protein (p-S6RP) as mTOR activity markers, CD31 to identify endothelial cells, and Ki-67 to show cellular proliferation. We counted cells in the epidermis and compared mTOR-positive cell counts between peripheral and central samples, and between patient groups, using Freidman test and Wilcoxon signed-rank test.

RESULTS

Ten patients with livedo reticularis were enrolled: 4 aPL-positive without SLE (antiphospholipid syndrome [APS] classification met, n = 3), 4 aPL-positive SLE (APS classification met, n = 3), and 2 aPL-negative SLE (control). In all aPL-positive patients, epidermal p-AKT and p-S6RP staining were significantly increased in both peripheral and central skin samples when compared to aPL-negative SLE controls; both were more pronounced in the lower basal layers of epidermis.

CONCLUSION

Our study demonstrates increased mTOR activity in livedoid lesions of aPL-positive patients with or without SLE compared to aPL-negative patients with SLE, with more prominent activity in the lower basal layers of the epidermis. These findings may serve as a basis for further investigating the mTOR pathway in aPL-positive patients.

A targetable pathway in neutrophils mitigates both arterial and venous thrombosis

Arterial and venous thrombosis constitutes a major source of morbidity and mortality worldwide. Long considered as distinct entities, accumulating evidence indicates that arterial and venous thrombosis can occur in the same populations, suggesting that common mechanisms are likely operative. Although hyperactivation of the immune system is a common forerunner to the genesis of thrombotic events in both vascular systems, the key molecular control points remain poorly understood. Consequently, antithrombotic therapies targeting the immune system for therapeutics gain are lacking. Here, we show that neutrophils are key effectors of both arterial and venous thrombosis and can be targeted through immunoregulatory nanoparticles. Using antiphospholipid antibody syndrome (APS) as a model for arterial and venous thrombosis, we identified the transcription factor Krüppel-like factor 2 (KLF2) as a key regulator of neutrophil activation. Upon activation through genetic loss of KLF2 or administration of antiphospholipid antibodies, neutrophils clustered P-selectin glycoprotein ligand 1 (PSGL-1) by cortical actin remodeling, thereby increasing adhesion potential at sites of thrombosis. Targeting clustered PSGL-1 using nanoparticles attenuated neutrophil-mediated thrombosis in APS and KLF2 knockout models, illustrating the importance and feasibility of targeting activated neutrophils to prevent pathological thrombosis. Together, our results demonstrate a role for activated neutrophils in both arterial and venous thrombosis and identify key molecular events that serve as potential targets for therapeutics against diverse causes of immunothrombosis.

A Case of Budd-Chiari Syndrome Associated With Antiphospholipid Syndrome Treated Successfully by Transjugular Intrahepatic Portosystemic Shunt

Budd Chiari syndrome (BCS) is defined as obstruction of hepatic venous outflow that can be located anywhere from small hepatic venules up to the entrance of inferior vena cava (IVC) into right atrium. Etiologies of BCS include myeloproliferative disorders, congenital, and acquired hypercoagulable states. Anticoagulation is the mainstay of treatment for all cases of BCS with a demonstrable hypercoagulable state. Interventional radiology procedures such as transjugular intrahepatic portosystemic shunting (TIPS) can be utilized to reduce portal hypertension and to improve complications related to portal hypertension. We present a patient with systemic lupus erythematosus who first presented with fever, weight loss, malar rash, alopecia, livedo reticularis, symmetric polyarthritis, pancytopenia, and class IV lupus nephritis when she was 23 years old. After receiving an induction treatment of cyclophosphamide and glucocorticoids, she received a maintenance treatment of azathioprine. She presented with ascites and abdominal pain when she was 36 and the abdominal imaging revealed reduced calibration of hepatic venules and intrahepatic segment of inferior vena cava. Lupus anticoagulant was positive and anti cardiolipin IgM and IgG were positive. Work up for hereditary hypercoagulable states was negative. Thus, the diagnosis was secondary antiphospholipid syndrome where BCS was the first clinical manifestation of the antiphospholipid syndrome. Patient was anticoagulated with warfarin and received diuretics for ascites. After the ascites became refractory to diuretics and the patient had multiple vertebral compression fractures due to volume overload secondary to ascites, she was successfully treated with TIPS. When control imaging was performed, 50% of stenosis was observed in the stent. Balloon dilation of the stent was performed. Interventional radiology techniques like TIPS can be used in BCS patients secondary to APS, in cases when medical treatment is insufficient to control complications of portal hypertension. In BCS patients secondary to APS, TIPS enables clinical improvement but due to the presence of endothelial dysfunction in APS patients, there is a risk of shunt dysfunction secondary to thrombosis or stenosis secondary to intimal hyperplasia. Therefore, strict anticoagulation and regular follow up of patients after TIPS is recommended. In cases with stent stenosis, reintervention may be necessary.

Anti-β2-GPI Antibodies Induce Endothelial Cell Expression of Tissue Factor by LRP6 Signal Transduction Pathway Involving Lipid Rafts

In this study we analyzed whether anti-β2-GPI antibodies from patients with APS induce the endothelial cell expression of Tissue Factor (TF) by a LRP6 signal transduction pathway involving lipid rafts. HUVEC were stimulated with affinity purified anti-β2-GPI antibodies. Both LRP6 and β-catenin phosphorylation, as well as TF expression, were evaluated by western blot. Results demonstrated that triggering with affinity purified anti-β2-GPI antibodies induced LRP6 phosphorylation with consequent β-catenin activation, leading to TF expression on the cell surface. Interestingly, the lipid rafts affecting agent methyl-β-cyclodextrin as well as the LRP6 inhibitor Dickkopf 1 (DKK1) partially reduced the anti-β2-GPI antibodies effect, indicating that the anti-β2-GPI effects on TF expression may depend on a signalling transduction pathway involving both lipid rafts and LRP6. An interaction between β2-GPI, LRP6 and PAR-2 within these microdomains was demonstrated by gradient fractionation and coimmunoprecipitation experiments. Thus, anti-β2-GPI antibodies react with their target antigen likely associated to LRP6 and PAR-2 within plasma membrane lipid rafts of the endothelial cell. Anti-β2-GPI binding triggers β-catenin phosphorylation, leading to a procoagulant phenotype characterized by TF expression. These findings deal with a novel signal transduction pathway which provides new insight in the APS pathogenesis, improving the knowledge of valuable therapeutic target(s).

Endothelial function and endothelial progenitor cells in systemic lupus erythematosus

The observations that traditional cardiovascular disease (CVD) risk factors fail to fully account for the excessive cardiovascular mortality in patients with systemic lupus erythematosus (SLE) compared with the general population have prompted in-depth investigations of non-traditional, SLE-related risk factors that contribute to cardiovascular complications in patients with SLE. Of the various perturbations of vascular physiology, endothelial dysfunction, which is believed to occur in the earliest step of atherosclerosis, has been extensively investigated for its contribution to CVD risk in SLE. Endothelial progenitor cells (EPCs), which play a crucial part in vascular repair, neovascularization and maintenance of endothelial function, are quantitatively and functionally reduced in patients with SLE. Yet, the lack of a unified definition of EPCs, standardization of the quantity and functional assessment of EPCs as well as endothelial function measurement pose challenges to the translation of endothelial function measurements and EPC levels into prognostic markers for CVD in patients with SLE. This Review discusses factors that contribute to CVD in SLE, with particular focus on how endothelial function and EPCs are evaluated currently, and how EPCs are quantitatively and functionally altered in patients with SLE. Potential strategies for the use of endothelial function measurements and EPC quantification as prognostic markers of CVD in patients with SLE, and the limitations of their prognostication potential, are also discussed.

Managing Antiphospholipid Syndrome in Children and Adolescents: Current and Future Prospects

Pediatric antiphospholipid syndrome (APS) is a rare acquired multisystem autoimmune thromboinflammatory condition characterized by thrombotic and non-thrombotic clinical manifestations. APS in children and adolescents typically presents with large-vessel thrombosis, thrombotic microangiopathy, and, rarely, obstetric morbidity. Non-thrombotic clinical manifestations are frequently seen in pediatric APS and may be present even before the vascular thrombotic events occur. We review insights into the pathogenesis of APS and discuss potential targets for therapy. The identification of multiple immunologic abnormalities in patients with APS reveals molecular targets for current or future treatment. Management strategies, especially for APS in adolescents, require screening for additional prothrombotic risk factors and consideration of counseling regarding contraceptive strategies, lifestyle recommendations, treatment adherence, and mental health issues associated with this autoimmune thrombophilia. The main goal of therapy in pediatric APS is the prevention of thrombosis. The management of acute thrombosis events in children and adolescents is the same as for primary APS, which involves isolated occurrences, and secondary APS, which is seen in association with another autoimmune disease, e.g., systemic lupus erythematosus. A pediatric hematologist should be consulted so other differential thrombophilic conditions can be eliminated. Therapy includes unfractionated heparin or low-molecular-weight heparin followed by vitamin K antagonists. Treatment of catastrophic APS involves triple therapy (anticoagulation, intravenous corticosteroid pulse therapy, and plasma exchange) and may include intravenous immunoglobulin for children and adolescents with this condition. New drugs such as eculizumab and sirolimus seem to be promising drugs for APS.

Differences in Endothelial Activation and Dysfunction Induced by Antiphospholipid Antibodies Among Groups of Patients With Thrombotic, Refractory, and Non-refractory Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by pregnancy morbidity or thrombosis and persistent antiphospholipid antibodies (aPL) that bind to the endothelium and induce endothelial activation, which is evidenced by the expression of adhesion molecules and the production of reactive oxygen species (ROS) and subsequent endothelial dysfunction marked by a decrease in the synthesis and release of nitric oxide (NO). These endothelial alterations are the key components for the development of severe pathological processes in APS. Patients with APS can be grouped according to the presence of other autoimmune diseases (secondary APS), thrombosis alone (thrombotic APS), pregnancy morbidity (obstetric APS), and refractoriness to conventional treatment regimens (refractory APS). Typically, patients with severe and refractory obstetric APS exhibit thrombosis and are classified as those having primary or secondary APS. The elucidation of the mechanisms underlying these alterations according to the different groups of patients with APS could help establish new therapies, particularly necessary for severe and refractory cases. Therefore, this study aimed to evaluate the differences in endothelial activation and dysfunction induced by aPL between patients with refractory obstetric APS and other APS clinical manifestations. Human umbilical vein endothelial cells (HUVECs) were stimulated with polyclonal immunoglobulin-G (IgG) from different groups of patients n = 21), including those with primary (VTI) and secondary thrombotic APS (VTII) and refractory primary (RI+), refractory secondary (RII+), and non-refractory primary (NR+) obstetric APS. All of them with thrombosis. The expression of adhesion molecules; the production of ROS, NO, vascular endothelial growth factor (VEGF), and endothelin-1; and the generation of microparticles were used to evaluate endothelial activation and dysfunction. VTI IgG induced the expression of adhesion molecules and the generation of microparticles and VEGF. RI+ IgG induced the expression of adhesion molecules and decreased NO production. RII+ IgG increased the production of microparticles, ROS, and endothelin-1 and reduced NO release. NR+ IgG increased the production of microparticles and endothelin-1 and decreased the production of VEGF and NO. These findings reveal differences in endothelial activation and dysfunction among groups of patients with APS, which should be considered in future studies to evaluate new therapies, especially in refractory cases.

Molecular mechanisms of vasculopathy and coagulopathy in COVID-19

COVID-19 primarily affects the respiratory system and may lead to severe systemic complications, such as acute respiratory distress syndrome (ARDS), multiple organ failure, cytokine storm, and thromboembolic events. Depending on the immune status of the affected individual early disease control can be reached by a robust type-I-interferon (type-I-IFN) response restricting viral replication. If type-I-IFN upregulation is impaired, patients develop severe COVID-19 that involves profound alveolitis, endothelitis, complement activation, recruitment of immune cells, as well as immunothrombosis. In patients with proper initial disease control there can be a second flare of type-I-IFN release leading to post-COVID manifestation such as chilblain-like lesions that are characterized by thrombosis of small vessels in addition to an inflammatory infiltrate resembling lupus erythematosus (LE). Mechanistically, SARS-CoV-2 invades pneumocytes and endothelial cells by acting on angiotensin-II-converting enzyme 2 (ACE2). It is hypothesized, that viral uptake might downregulate ACE2 bioavailability and enhance angiotensin-II-derived pro-inflammatory and pro-thrombotic state. Since ACE2 is encoded on the X chromosome these conditions might also be influenced by gender-specific regulation. Taken together, SARS-CoV-2 infection affects the vascular compartment leading to variable thrombogenic or inflammatory response depending on the individual immune response status.

A Case of COVID-19 Vaccine-Induced Thrombotic Thrombocytopenia

SARS-CoV-2, which originated in China in late 2019, has spread rapidly resulting in a global pandemic. Multiple vaccines have been developed to help prevent COVID-19 infection. Similar to other vaccines, common side effects including fever, fatigue, myalgias have occurred; however, episodes of more serious side effects have been noted. One such potentially serious sequalae is vaccine-induced thrombocytopenia (VITT), an autoimmune-mediated phenomenon hypothesized to occur due to molecular mimicry and the production of platelet PF4 antibodies, ultimately leading to thrombocytopenia and easy bruising. In this report, we present the case of a 34-year-old, otherwise, healthy female who presented with easy bruising and thrombocytopenia following completion of the two-dose Moderna COVID-19 vaccine, suspicious for a diagnosis of VITT. The patient was managed conservatively with steroids. Steroids and intravenous immune globulin therapy have been reported in the literature. This report highlights that VITT should be considered in the differential diagnosis for patient presenting with increased bruising in the setting of recent COVID-19 vaccine administration, and furthermore highlights the diagnostic workup and management options for such patients.

Effects of anti-beta 2-glycoprotein 1 antibodies and its association with pregnancy-related morbidity in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous, arterial, or small-vessel thrombosis and/or pregnancy-related morbidity, associated with persistent positivity of antiphospholipid antibodies (aPL). Pregnancy-related morbidity in APS patients is characterized by unexplained fetal deaths, premature birth of morphologically normal newborns, and/or consecutive pregnancy losses before the 10^th week of gestation. Beta 2-glycoprotein 1 (ß2GP1) is the main antigen recognized by aPL and plays an essential role in the pathogenesis of APS. Antibodies against ß2GP1 (aß2GP1) are involved in damage-generating mechanisms in APS due to their interaction with trophoblasts, decidua, and endothelial cells. aß2GP1 might be used as a prognostic tool for obstetric risk stratification and ß2GP1 could be a target for molecular-targeted treatment to prevent pregnancy morbidity in APS. This review describes these aspects of aß2GP1, including effects on different cellular targets, its association with the severity of obstetric manifestations and the potential of ß2GP1-targeted therapies for APS.

Altered platelet and coagulation function in moderate-to-severe COVID-19

To reveal if coagulopathies relate to the course of COVID-19, we examined 255 patients with moderate and severe COVID-19, receiving anticoagulants and immunosuppressive drugs. Coagulopathy manifested predominantly as hypercoagulability that correlated directly with systemic inflammation, disease severity, comorbidities, and mortality risk. The prolonged clotting tests in about ¼ of cases were associated with high levels of C-reactive protein and antiphospholipid antibodies, which impeded coagulation in vitro. Contraction of blood clots was hindered in about ½ of patients, especially in severe and fatal cases, and correlated directly with prothrombotic parameters. A decrease in platelet contractility was due to moderate thrombocytopenia in combination with platelet dysfunction. Clots with impaired contraction were porous, had a low content of compressed polyhedral erythrocytes (polyhedrocytes) and an even distribution of fibrin, suggesting that the uncompacted intravital clots are more obstructive but patients could also be prone to bleeding. The absence of consumption coagulopathy suggests the predominance of local and/or regional microthrombosis rather than disseminated intravascular coagulation. The results obtained (i) confirm the importance of hemostatic disorders in COVID-19 and their relation to systemic inflammation; (ii) justify monitoring of hemostasis, including the kinetics of blood clot contraction; (iii) substantiate the active prophylaxis of thrombotic complications in COVID-19.

Change of serum B-cell activating factor level in patients with positive antiphospholipid antibodies and previous adverse pregnancy outcomes and its significance

Background:

B-cell activating factor (BAFF) is vital for B cell survival. Serum BAFF levels are elevated in thrombotic antiphospholipid syndrome, but little is known about levels in patients with positive antiphospholipid antibodies (aPLs) and previous adverse pregnancy outcomes (APOs). We aimed to analyze serum BAFF concentrations of these patients in early pregnancy along with different pregnancy outcomes.

Methods:

Thirty-six pregnant patients positive for aPLs and previous APOs (patient group), 25 healthy pregnant females (HP group) and 35 healthy non-pregnant females (HNP group) from the Peking University Third Hospital, between October 2018 and March 2019, were enrolled in this study. Serum of HNP and serum of patients as well as HP in the first gestational trimester were collected. Enzyme-linked immunosorbent assay kits were used to measure serum BAFF and interferon-alpha (IFN-α) concentrations. Cytometric bead array analysis was used to measure serum concentrations of cytokines. The patient group was further divided into APOs and non-APOs (NAPOs) group, fetal loss and live birth group according to pregnancy outcomes. The Mann-Whitney U-test was used to assess significance between and within groups. Spearman rank-order was used to evaluate correlation coefficients between BAFF and related cytokines.

Results:

The serum BAFF level in HP group was significantly lower than HNP group (245.24 [218.80, 265.90] vs. 326.94 [267.31, 414.80] pg/mL, Z = −3.966, P < 0.001). The BAFF level was obviously elevated in patient group compared to that in HP group (307.77 [219.86, 415.65] vs. 245.24 [218.80, 265.90] pg/mL, Z = −2.464, P = 0.013). BAFF levels in APOs group tended to be higher than that in NAPOs group (416.52 [307.07, 511.12] vs. 259.37 [203.59, 375.81] pg/mL, Z = −2.718, P = 0.006). Compared to HP group, concentrations of IFN-α, interleukin (IL-6) and tumor necrosis factor were higher in patient group (33.37 [18.85, 48.12] vs. 13.10 [6.85, 25.47] pg/mL, Z = −2.023, P = 0.043; 39.16 [4.41, 195.87] vs. 3.37 [2.92, 3.90] pg/mL, Z = −3.650, P < 0.001; 8.23 [2.27, 64.46] vs. 1.53 [1.25, 2.31] pg/mL, Z = −3.604, P < 0.001, respectively). Serum BAFF levels had a positive correlation with the concentrations of both IL-6 and IL-10 (IL-6: r = 0.525, P = 0.002; IL-10: r = 0.438, P = 0.012).

Conclusions:

Serum BAFF levels are increased in patients with positive aPLs and previous APOs as compared to healthy pregnant females and tend to be higher in individuals with current APOs. The BAFF levels have a positive correlation with serum IL-6 and IL-10.

Exosome-Contained APOH Associated With Antiphospholipid Syndrome

Background

Antiphospholipid syndrome (APS) is a systemic autoimmune disease that can lead to thrombosis and/or pregnancy complications. Exosomes, membrane-encapsulated vesicles that are released into the extracellular environment by many types of cells, can carry signals to recipient cells to affect angiogenesis, apoptosis, and inflammation. There is increasing evidence suggesting that exosomes play critical roles in pregnancy. However, the contribution of exosomes to APS is still unknown.

Methods

Peripheral plasma was collected from healthy early pregnancy patients (NC-exos) and early pregnancy patients with APS (APS-exos) for exosome extraction and characterization. The effect of exosomes from different sources on pregnancy outcomes was determined by establishing a mouse pregnancy model. Following the coincubation of exosomes and human umbilical vein endothelial cells (HUVECs), functional tests examined the features of APS-exos. The APS-exos and NC-exos were analyzed by quantitative proteomics of whole protein tandem mass tag (TMT) markers to explore the different compositions and identify key proteins. After incubation with HUVECs, functional tests investigated the characteristics of key exosomal proteins. Western blot analysis was used to identify the key pathways.

Results

In the mouse model, APS-exos caused an APS-like birth outcome. In vitro experiments showed that APS-exos inhibited the migration and tube formation of HUVECs. Quantitative proteomics analysis identified 27 upregulated proteins and 9 downregulated proteins in APS-exos versus NC-exos. We hypothesized that apolipoprotein H (APOH) may be a core protein, and the analysis of clinical samples was consistent with finding from the proteomic TMT analysis. APOH-exos led to APS-like birth outcomes. APOH-exos directly enter HUVECs and may play a role through the phospho-extracellular signal-regulated kinase pathway.

Conclusions

Our study suggests that both APS-exos and APOH-exos impair vascular development and lead to pregnancy complications. APOH-exos may be key actors in the pathogenesis of APS. This study provides new insights into the pathogenesis of APS and potential new targets for therapeutic intervention.

Microparticles: An Alternative Explanation to the Behavior of Vascular Antiphospholipid Syndrome

Antiphospholipid syndrome is an autoimmune disease characterized by the persistent presence of antiphospholipid antibodies, along with occurrence of vascular thrombosis and pregnancy morbidity. The variety of antiphospholipid antibodies and their related mechanisms, as well as the behavior of disease in wide groups of patients, have led some authors to propose a differentiation of this syndrome into two independent entities: vascular and obstetric antiphospholipid syndrome. Thus, previous studies have discussed whether specific autoantibodies may be responsible for this differentiation or, in contrast, how the same antibodies are able to generate two different clinical presentations. This discussion is yet to be settled. The capability of serum IgG from patients with vascular thrombosis to trigger the biogenesis of endothelial cell-derived microparticles in vitro is one of the previously discussed differences between the clinical entities of antiphospholipid syndrome. These vesicles constitute a prothrombotic mechanism as they can directly lead to clot activation in murine models and recalcified human plasma. Nevertheless, other indirect mechanisms by which microparticles can spread a procoagulant phenotype could be critical to understanding their role in antiphospholipid syndrome. For this reason, questions regarding the cargo of microparticles, and the signaling pathways involved in their biogenesis, are of interest in attempting to explain the behavior of this autoimmune disease.

Extracellular Vesicles and Antiphospholipid Syndrome: State-of-the-Art and Future Challenges

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by thromboembolism, obstetric complications, and the presence of antiphospholipid antibodies (aPL). Extracellular vesicles (EVs) play a key role in intercellular communication and connectivity and are known to be involved in endothelial and vascular pathologies. Despite well-characterized in vitro and in vivo models of APS pathology, the field of EVs remains largely unexplored. This review recapitulates recent findings on the role of EVs in APS, focusing on their contribution to endothelial dysfunction. Several studies have found that APS patients with a history of thrombotic events have increased levels of EVs, particularly of endothelial origin. In obstetric APS, research on plasma levels of EVs is limited, but it appears that levels of EVs are increased. In general, there is evidence that EVs activate endothelial cells, exhibit proinflammatory and procoagulant effects, interact directly with cell receptors, and transfer biological material. Future studies on EVs in APS may provide new insights into APS pathology and reveal their potential as biomarkers to identify patients at increased risk.

Clinical value of amyloid-beta1-40 as a marker of thrombo-inflammation in antiphospholipid syndrome

OBJECTIVE

Amyloid-beta1-40 (Aβ40) is a pro-inflammatory peptide under investigation as a novel biomarker of vascular inflammation, endothelial dysfunction and atherothrombosis in the general population. Herein we tested the hypothesis that Aβ40 is deregulated in APS, a systemic autoimmune disease characterized by a thrombo-inflammatory state.

METHODS

Between January 2016 and July 2017, we consecutively recruited 80 regularly followed thrombotic APS patients (44 primary, 36 SLE/APS) and 80 age- and sex-matched controls. Plasma Aβ40 levels were measured using ELISA and APS-related clinical and laboratory characteristics were recorded. The adjusted Global Anti-Phospholipid Syndrome Score (aGAPSS), a validated risk score in APS, was calculated as a comparator to Aβ40 performance to detect arterial thrombotic APS-related events.

RESULTS

Higher Aβ40 levels were significantly associated with the presence of APS [odds ratio (OR) 1.024 per 1 pg/ml (95% CI 1.007, 1.041)] after adjustment for cardiovascular risk factors (CVRFs), including smoking, arterial hypertension, dyslipidaemia and BMI, and for estimated glomerular filtration rate (eGFR). Among APS patients, increased high-sensitivity CRP (hs-CRP) serum levels was the only independent determinant of Aβ40 levels. Importantly, Aβ40 levels above the optimal receiver operating characteristics (ROC)-derived cut-off value were independently associated with recurrent arterial events [OR 4.93 (95% CI 1.31, 18.51)] after adjustment for age, sex, CVRFs, hs-CRP and high anti-β2 glycoprotein I IgG titres. Finally, by ROC curve analysis, Aβ40 provided incremental additive value over the aGAPSS by significantly improving its discrimination ability for recurrent arterial thromboses.

CONCLUSION

In APS, Aβ40 plasma levels are elevated and associated with an adverse thrombo-inflammatory profile. The pathophysiological and prognostic role of Aβ40 in APS merits further investigation.

Ocular microvascular damage in autoimmune rheumatic diseases: The pathophysiological role of the immune system

Pathological eye involvement represents a quite common finding in a broad spectrum of autoimmune rheumatic diseases (ARDs). Ocular signs, often occur as early manifestations in ARDs, ranging from symptoms related to the mild dry eye disease to sight-threatening pathologies, linked to the immune response against retinal and choroidal vessels. Retinovascular damage driven by markedly inflammatory reactivity need a prompt diagnosis and treatment. Immune-complexes formation, complement activation and antibody-mediated endothelial damage seem to play a key role, particularly, in microvascular damage and ocular symptoms, occurring in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren's syndrome (SS). Conversely, early alterations of retinal and choroidal vessels in the asymptomatic patient, often detectable coincidentally, might be indicators of widespread vascular injury in other connective tissue diseases. Particularly, endothelin-induced hypoperfusion and pathological peri-choroidal extracellular matrix deposition, might be responsible for the micro-architectural alterations and loss of capillaries detected in systemic sclerosis (SSc). Instead, interferon alpha-mediated microvascular rarefaction, combined with endothelial lesions caused by specific autoantibodies and immune-complexes, appear to play a significant role in retinal vasculopathy associated to inflammatory idiopathic myopathies (IIM). The immuno-pathophysiological mechanisms of ocular microcirculatory damage associated with the major ARDs will be discussed under the light of the most recent achievements.

Association of systemic lupus erythematosus with peripheral arterial disease: a meta-analysis of literature studies

OBJECTIVE

SLE patients have an increased cardiovascular morbidity and mortality. Contrasting data are available about the association between peripheral arterial disease (PAD) and SLE. We aimed to perform a meta-analysis of studies evaluating the association between SLE and PAD.

METHODS

Studies were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases according to preferred reporting items for systematic reviews and meta-analyses guidelines.

RESULTS

Eight studies reporting on 263 258 SLE patients and 768 487 controls showed that the prevalence of PAD was 15.8% (95% CI: 10.5%, 23.2%) in SLE patients and 3.9% (95% CI: 1.8%, 7.9%) in controls with a corresponding odds ratio of 4.1 (95% CI: 1.5, 11.6; P <0.001). In addition, five studies reporting on ankle-brachial index showed significantly lower values in 280 SLE patients as compared with 201 controls (mean difference: -0.018; 95% CI: -0.034, -0.001; P =0.033). Meta-regression models showed that age, hypertension and diabetes were inversely associated with the difference in the prevalence of PAD between SLE patients and non-SLE controls, whereas no effect for all the other clinical and demographic variables on the evaluated outcome was found.

CONCLUSION

SLE patients exhibit an increased prevalence of PAD and lower ankle-brachial index values as compared with non-SLE controls. This should be considered when planning prevention, interventional and rehabilitation strategies for these chronic patients with functional disability and poor long-term outcomes.

Antiphospholipid syndrome

Antiphospholipid syndrome is one of the more common acquired causes of hypercoagulability. Its major presentations are thrombotic (arterial, venous, or microvascular) and pregnancy morbidity (miscarriages, late intrauterine fetal demise, and severe pre-eclampsia). Classification criteria include 3 different antiphospholipid antibodies: lupus anticoagulant, anticardiolipin, and anti-beta 2 glycoprotein I. Management includes both preventive strategies (low-dose aspirin, hydroxychloroquine) and long-term anticoagulation after thrombosis.

COVID-19: A Great Mime or a Trigger Event of Autoimmune Manifestations?

Viruses can induce autoimmune diseases, in addition to genetic predisposition and environmental factors. Particularly, coronaviruses are mentioned among the viruses implicated in autoimmunity. Today, the world's greatest threat derives from the pandemic of a new human coronavirus, called "severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the responsible agent of coronavirus disease 2019 (COVID-19). First case of COVID-19 was identified in Wuhan, the capital of Hubei, China, in December 2019 and quickly spread around the world. This review focuses on autoimmune manifestations described during COVID-19, including pro-thrombotic state associated with antiphospholipid antibodies (aPL), acute interstitial pneumonia, macrophage activation syndrome, lymphocytopenia, systemic vasculitis, and autoimmune skin lesions. This offers the opportunity to highlight the pathogenetic mechanisms common to COVID-19 and several autoimmune diseases in order to identify new therapeutic targets. In a supposed preliminary pathogenetic model, SARS-CoV-2 plays a direct role in triggering widespread microthrombosis and microvascular inflammation, because it is able to induce transient aPL, endothelial damage and complement activation at the same time. Hence, endothelium might represent the common pathway in which autoimmunity and infection converge. In addition, autoimmune phenomena in COVID-19 can be explained by regulatory T cells impairment and cytokines cascade.

Hematologic parameters in coronavirus infection (COVID-19) and their clinical implications

Coronaviruses are a class of enveloped RNA viruses that cause infections of the respiratory tract, characterized by fever, tiredness, dry cough, diarrhea, loss of smell or taste, chest pain and shortness of breath. Many patients with mysterious pneumonia were distinguished in December 2019 in Wuhan. The pneumonia of obscure origin was found to be ascribed to a novel coronavirus and described as novel coronavirus pneumonia (NCP). The Chinese authorities initially reported the wave of mysterious pneumonia on December 31st, 2019 and it was declared as an outbreak of international concern on January 30th, 2020. A systematic search of relevant research was conducted, and a total of 58 primary research articles were identified, analyzed, and debated to better understand the hematologic profile in COVID-19 (Coronavirus disease) infection and its clinical implications. All the findings in this article manifest a true impression of the current interpretation of hematological findings of the SARS-COV-2 disease. Pathophysiology of COVID-19 disease can be better interpreted by taking into consideration the hematologic parameters. Clinical implications of the hematologic profile of COVID-19 patients including cytokine storm, coagulation profile, and thrombophilic complications are under-recognized. Therefore, this review focuses on the coagulation profile, cytokine storm, and its treatment options. The role of pre-existing thrombophilia in COVID-19 patients and how it could result in the poor prognosis of the disease is also debated. The recent data suggests that hypercoagulability could be the potential cause of fatalities due to COVID-19. Potential effects of tocilizumab, metronidazole, and ulinastatin in suppressing cytokine storm may help to treat SARS-COV-2 infection. This review also highlights the significance of thrombophilia testing in SARS-CoV-2 patients depending on the clinical features and especially in pregnant women.

Tongue Stiffness as Presentation of Antiphospholipid Syndrome: A Case Report

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder with marked thrombotic and inflammatory features driven by the presence of antiphospholipid antibodies (APLA). Here, we report a case of APS with a rare, atypical manifestation and discuss a differential diagnosis.

A 53-year-old male without significant past medical history presented with new onset of episodic tongue stiffness and dysarthria which lasted for about a minute over a period of three months. This was associated with intermittent right retro-orbital sharp pain radiating to the parietal area. He also reported swelling and stiffness of the third and fourth right proximal interphalangeal (PIP) joints lasting throughout the day. A physical exam revealed tongue fasciculations. As the MRI showed patchy white matter hyperintensities neurology initially suspected multiple sclerosis. However, cerebrospinal fluid (CSF) analysis including neuromyelitis optica (NMO) antibodies and oligoclonal antibodies was negative. Rheumatological work up was remarkable for positive antinuclear antibodies (ANA); anticardiolipin antibodies and lupus anticoagulant were positive 12 weeks apart. This, alongside with stable white matter changes on imaging was suspicious for an extra-criteria manifestation of antiphospholipid antibody syndrome.

The most commonly described neurological manifestations of APS are headache, transient ischemic attack (TIA), and stroke. Tongue stiffness as an initial symptom is quite unusual and, to the best of our knowledge has not been reported in medical literature. In patients with isolated neurological findings of unclear etiology, an autoimmune disease such as APS should be considered, and appropriate diagnostic work up should not be postponed. Unfortunately, positive laboratory markers can have a wide differential diagnostic panel. In addition, APS may mimic many diseases both in clinical presentation and MRI findings thus making the correct diagnosis challenging. However, studies show that, unlike multiple sclerosis (MS), white matter changes in APS remain static during the course of the disease. Identification of atypical presentations of APS is critical as prompt and correct medical management can improve patients’ quality of life and clinical outcomes.

Clinical features associated with pregnancy outcomes in women with positive antiphospholipid antibodies and previous adverse pregnancy outcomes: a real-world prospective study

OBJECTIVE

This study aims to analyze factors related to pregnancy outcomes in women with positive antiphospholipid antibodies and previous adverse pregnancy outcomes (APOs) prospectively.

METHODS

Patients' characteristics were described. Factors associated with obstetric complications were analyzed using logistic regression analysis.

RESULTS

A total of 128 females with 73.4% non-criteria obstetric antiphospholipid syndrome (NC-OAPS) were included. APOs accounted for 38.3%, of which 65.3% were fetal losses. Live birth rates in criteria OAPS and NC-OAPS were similar (76.5% and 74.5%). For the whole patients, antinuclear antibody (ANA) titer ≥ 1:160 (OR 5.064, 95% CI (1.509, 16.995), P = 0.009) was a risk factor for APOs and low molecular weight heparin (LMWH) use (OR 0.149, 95% CI (0.029, 0.775), P = 0.024)) was a protective factor. Age (OR 1.159, 95% CI (1.011, 1.329), P = 0.034) and previous APOs ≥ 3 times (OR 3.772, 95% CI (1.14, 12.435), P = 0.029) were risk factors for fetal loss, and LMWH use (OR 0.068, 95% CI (0.009, 0.486), P = 0.007) was a protective factor. Regular rheumatology visits was a protective factor for APOs and fetal loss (OR 0.085, 95% CI (0.024, 0.306), P < 0.001; OR 0.019, 95% CI (0.004, 0.104), P < 0.001). The proportion of it decreased in APOs and fetal loss groups (53.1% and 28.1%). Glucocorticoid use was a risk factor for APOs in NC-OAPS and higher serum C3 levels in the first gestational trimester was a protective factor for fetal loss (OR 3.703, 95% CI (1.402, 9.777), P = 0.008; OR 0.041, 95% CI (0.002, 0.947), P = 0.046).

CONCLUSION

Age, APO history, ANA titer, LWMH and glucocorticoid use, serum C3 levels, and regular rheumatology visits were related to obstetric complications. Key Points • This was one of the few prospective studies focused on patients with positive antiphospholipid antibodies and previous adverse pregnancy outcomes. The majority were NC-OAPS patients. • The study first evaluated the impact of rheumatologists' monitoring based on individual disease assessments on pregnancy outcomes. The live birth proportion was similar in patients with criteria OAPS and NC-OAPS when treated. • Age, APO history (≥ 3 times), ANA titer (≥ 1:160), LMWH use, glucocorticoid use, and serum C3 were factors related to obstetric complications.

IMPACT OF NITRIC OXIDE SYNTHESIS MODULATORS ON THE CYTOKINES PROFILE IN EXPERIMENTAL ANTIPHOSPHOLIPID SYNDROME

Background.  Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of specific antibodies. Objective. The aim of the study was to investigate the effect of combined use of L-arginine and aminoguanidine on cytokine profile (IL-1β, IL-6, TNF-α, IL-4, IL-10) in experimental APS. Methods. The study was performed on BALB/c female mice. L-arginine (25 mg/kg) and aminoguanidine (10 mg/kg) were used for correction. Serum cytokines concentrations were assessed using an ELISA test. Results. It was found that in APS the concentration of proinflammatory cytokines IL-1β, IL-6 and TNF-a increases in 3.2, 2.3 and 4.5 times respectively, compare to the control. At the same time a decrease of the IL-4 and IL-10 in 1.9 and 2.2 times was evidenced. Aminoguanidine, a selective iNOS inhibitor, caused a significant decrease of TNF-α by 57% (p<0.001), but there were no changes in IL-1β, IL-6, IL-4 and IL-10 compare to the APS-group. L-arginine combined with aminoguanidine caused a significant decrease in the concentration of IL-1β by 30% (p<0.01), IL-6 – by 16% (p<0.05), TNF-a – by 59% (p<0.001) compare to the control. At the same time, the concentration of IL-4 increased by 35% (p <0.01), IL-10 – by 25% (p<0.005). Conclusions. Combined use of the precursor of the NO synthesis L-arginine and aminoguanidine, a selective iNOS inhibitor, leads to a decrease in the concentrations of IL-1β, IL-6, TNF-a and an increase of IL-4 and IL-10 compare to the group of the BALB/c mice with APS and the group of animals administered with aminoguanidine.

Effects of antibodies against human parvovirus B19 on angiogenic signaling

Human parvovirus B19 (B19V) infection has symptoms similar to those of anti‑phospholipid syndrome (APS). Antibodies against B19V‑VP1 unique region (VP1u) exhibit activity similar to that of anti‑phospholipid antibodies (aPLs) by inducing vascular endothelial cell adhesion factors and APS‑like syndrome. Previous studies have identified an effect of aPLs on angiogenesis. However, little is understood regarding the effect of anti‑B19V‑VP1u antibodies on angiogenesis. The present study investigated the effects of anti‑B19V‑VP1u antibodies on the expression of adhesion molecules and angiogenic signaling using an aPL‑induced human umbilical vein endothelial cell (HUVEC) model, and trypan blue staining and western blotting. The effect of B19V‑VP1u antibodies on vascular endothelial growth factor (VEGF) expression in A549 cells, another well‑known model used to study angiogenesis, was also examined. Significantly higher intracellular adhesion molecule 1 expression was observed following treatments with 10% fetal calf serum (FCS), aPL immunoglobulin G (IgG), B19V‑VP1u IgG or B19V‑NS1 IgG, compared with in the normal human (NH) IgG‑treated cells. Conversely, significantly higher vascular cellular adhesion molecule 1 was only detected in HUVECs treated with B19V‑VP1u IgG. Significantly increased integrin β1 was detected in HUVECs treated with aPL IgG or B19V‑VP1u IgG, whereas no difference in integrin β1 was observed in those treated with 10% FCS, NH IgG or B19V‑NS1 IgG. No difference in AKT‑mTOR‑S6 ribosomal protein (S6RP) signaling was observed in HUVECs treated with B19‑VP1u IgG or B19V‑NS1 IgG, compared with NH IgG‑treated cells. Significantly higher human inducible factor‑1α was detected in HUVECs treated with 10% FCS, aPL IgG, B19V‑VP1u IgG or B19V‑NS1 IgG, compared with in NH IgG‑treated cells. However, there was no difference in the level of VEGF observed among HUVECs treated with NH IgG, B19V‑VP1u IgG or B19V‑NS1 IgG. Notably, no difference in VEGF level was observed in A549 cells treated with NH IgG, aPL IgG, B19V‑VP1u IgG or B19V‑NS1 IgG. These findings suggest that anti‑B19V‑VP1u antibodies may serve a role in activating adhesion molecules, but not in AKT‑mTOR‑S6RP signaling.

An inhibitor of myosin II, blebbistatin, suppresses development of arterial thrombosis

Arterial thrombosis (AT) causes various ischemia-related diseases, which impose a serious medical burden worldwide. As an inhibitor of myosin II, blebbistatin has an important role in thrombosis development. We investigated the effect of blebbistatin on carotid artery ligation (CAL)-induced carotid AT and its potential underlying mechanism. A model of carotid AT in mice was generated by CAL. Mice were divided into three groups: CAL model, blebbistatin-treated, and sham-operation. After 7 days, blood vessels were harvested from mice in each group. The procoagulant activity of tissue factor (TF) was tested by a chromogenic assay, and thrombus severity assessed by histopathology scores. Expression of non-muscle myosin heavy chain II A (NMMHCIIA), TF, glycogen synthase kinase 3β (GSK3β), and nuclear factor-kappa B (NF-κB) was detected by immunohistochemical and immunofluorescence staining. mRNA expression was measured by quantitative polymerase chain reaction. Blebbistatin (1 mg/kg) inhibited development of carotid AT, reduced infiltration of inflammatory cells, and prevented vascular-tissue damage, relative to the model group. Furthermore, blebbistatin also reduced the procoagulant activity of TF. Immunohistochemical and immunofluorescence data demonstrated that, compared with the model group, blebbistatin intervention reduced expression of NMMHCIIA, TF, GSK3β, p65, and p-p65 in carotid-artery endothelia in the CAL-induced AT model, but it increased levels of p-GSK3β. Blebbistatin could inhibit expression of NMMHCIIA mRNA in the CAL model. Overall, our data demonstrated that blebbistatin could inhibit TF expression and AT development in arterial endothelia (at least in part) via GSK3β/NF-κB signaling.