Hydroxychloroquine reverses the prothrombotic state in a mouse model of antiphospholipid syndrome: Role of reduced inflammation and endothelial dysfunction

Hydroxychloroquine inhibits hemolysis-induced arterial thrombosis ex vivo and improves lung perfusion in hemin-treated mice

BACKGROUND

Free labile hemin acts as a damage-associated molecular pattern during acute and chronic hemolysis and muscle injury, supporting platelet activation and thrombosis.

OBJECTIVES

To investigate the anti-thrombotic potential of hydroxychloroquine on hemolysis-induced platelet activation and arterial thrombosis.

METHODS

The effect of hydroxychloroquine on hemin-induced platelet activation and hemolysis-induced platelet recruitment and aggregation was measured in washed platelets and hemolyzed blood, respectively. Its effect on ferric-chloride (FeCl3)-induced arterial thrombosis and lung perfusion following hemin injection was assessed in wild-type mice.

RESULTS

Erythrocyte lysis and endothelial cell activation cooperatively supported platelet aggregation and thrombosis at arterial shear stress. This thrombotic effect was reversed by hydroxychloroquine. In a purified system, hydroxychloroquine inhibited platelet build-up on immobilized von Willebrand factor in hemolyzed blood without altering initial platelet recruitment. Hydroxychloroquine inhibited hemin-induced platelet activation and phosphatidylserine exposure independently of reactive oxygen species generation. In the presence of hemin, hydroxychloroquine did not alter glycoprotein VI shedding but reduced C-type-lectin-like-2 expression on platelets. In vivo, hydroxychloroquine reversed pulmonary perfusion decline induced by exogenous administration of hemin. In arterial thrombosis models, hydroxychloroquine inhibited ferric-chloride-induced thrombosis in the carotid artery and reduced von Willebrand factor accumulation in the thrombi.

CONCLUSION

Hydroxychloroquine inhibited hemolysis-induced arterial thrombosis ex vivo and improved pulmonary perfusion in hemin-treated mice, supporting a potential benefit of its use as an adjuvant therapy in hemolytic diseases to limit arterial thrombosis and to improve organ perfusion.

Deciphering the immunological interactions: targeting preeclampsia with Hydroxychloroquine's biological mechanisms

Preeclampsia (PE) is a complex pregnancy-related disorder characterized by hypertension, followed by organ dysfunction and uteroplacental abnormalities. It remains a major cause of maternal and neonatal morbidity and mortality worldwide. Although the pathophysiology of PE has not been fully elucidated, a two-stage model has been proposed. In this model, a poorly perfused placenta releases various factors into the maternal circulation during the first stage, including pro-inflammatory cytokines, anti-angiogenic factors, and damage-associated molecular patterns into the maternal circulation. In the second stage, these factors lead to a systemic vascular dysfunction with consecutive clinical maternal and/or fetal manifestations. Despite advances in feto-maternal management, effective prophylactic and therapeutic options for PE are still lacking. Since termination of pregnancy is the only curative therapy, regardless of gestational age, new treatment/prophylactic options are urgently needed. Hydroxychloroquine (HCQ) is mainly used to treat malaria as well as certain autoimmune conditions such as systemic lupus and rheumatoid arthritis. The exact mechanism of action of HCQ is not fully understood, but several mechanisms of action have been proposed based on its pharmacological properties. Interestingly, many of them might counteract the proposed processes involved in the development of PE. Therefore, based on a literature review, we aimed to investigate the interrelated biological processes of HCQ and PE and to identify potential molecular targets in these processes.

The effects of hydroxychloroquine and its promising use in refractory obstetric antiphospholipid syndrome

Hydroxychloroquine (HCQ) is obtained by hydroxylation of chloroquine (CQ) and the first indication was malaria. Nowadays, HCQ is commonly used in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) with favorable results. Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombosis and/or pregnancy morbidity and persistent positivity of antiphospholipid antibodies. Around 20-30% of pregnant women with APS develop adverse pregnancy outcomes despite conventional treatment with aspirin and heparin, called refractory obstetric APS. Interestingly, HCQ has shown positive effects on top of the standard of care in some refractory obstetric APS patients. HCQ mechanisms of action in APS comprise its ability to bind sialic acid present in cell membranes, its capacity to block the binding of antiphospholipid antibodies to the cell and the induced increase of pH in extracellular and intracellular compartments. However, the precise mechanisms of HCQ in the specific situation of refractory APS still need to be fully clarified. Therefore, this review summarizes the known modulating effects of HCQ and CQ, their side effects and use in APS and different pathologies to understand the benefit effects and the mechanism of action of HCQ in refractory obstetric APS.

Lipid-binding antiphospholipid antibodies: significance for pathophysiology and diagnosis of the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of pathogenic antiphospholipid antibodies (aPL). Since approximately 30 years ago, lipid-binding aPL, which do not require a protein cofactor, have been regarded as irrelevant for APS pathogenesis even though anticardiolipin are a diagnostic criterion of APS. In this review, we will summarize the available evidence from in vitro studies, animal models, and epidemiologic studies, which suggest that this concept is no longer tenable. Accordingly, we will only briefly touch on the role of other aPL in APS. This topic has been amply reviewed in detail elsewhere. We will discuss the consequences for laboratory diagnostics and future research required to resolve open questions related to the pathogenic role of different aPL specificities.

Metabolic Modulators in Cardiovascular Complications of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multifactorial disorder with contributions from hormones, genetics, and the environment, predominantly affecting young women. Cardiovascular disease is the primary cause of mortality in SLE, and hypertension is more prevalent among SLE patients. The dysregulation of both innate and adaptive immune cells in SLE, along with their infiltration into kidney and vascular tissues, is a pivotal factor contributing to the cardiovascular complications associated with SLE. The activation, proliferation, and differentiation of CD4+ T cells are intricately governed by cellular metabolism. Numerous metabolic inhibitors have been identified to target critical nodes in T cell metabolism. This review explores the existing evidence and knowledge gaps concerning whether the beneficial effects of metabolic modulators on autoimmunity, hypertension, endothelial dysfunction, and renal injury in lupus result from the restoration of a balanced immune system. The inhibition of glycolysis, mitochondrial metabolism, or mTORC1 has been found to improve endothelial dysfunction and prevent the development of hypertension in mouse models of SLE. Nevertheless, limited information is available regarding the potential vasculo-protective effects of drugs that act on immunometabolism in SLE patients.

Endothelial Progenitor Cells in Autoimmune Disorders

Circulating endothelial progenitor cells (EPCs) were first described in 1997 by Asahara et al. as "putative endothelial cells" from human peripheral blood. The study of endothelial progenitors is also intensifying in several pathologies associated with endothelial damage, including diabetes, myocardial infarction, sepsis, pulmonary arterial hypertension, obstructive bronchopneumopathy and transplantation. EPCs have been studied in several autoimmune diseases with endothelial involvement such as systemic lupus erythematosus, thrombotic thrombocytopenic purpura, antineutrophil cytoplasmic antibodies, vasculitis, rheumatoid arthritis, Goujerot-Sjögren and antiphospholipid syndrome. Factors involved in endothelial damage are due to overexpression of pro-inflammatory cytokines and/or autoantibodies. Management of these pathologies, particularly the long-term use of glucocorticoids and methotrexate, promote atherosclerosis. A lack of standardized assessment of the number and function of EPCs represents a serious challenge for the use of EPCs as prognostic markers of cardiovascular diseases (CVD). The objective of this review was to describe EPCs, their properties and their involvement in several autoimmune diseases.

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.

Superficial Dermatophytosis across the World's Populations: Potential Benefits from Nanocarrier-Based Therapies and Rising Challenges

The most prevalent infection in the world is dermatophytosis, which is a major issue with high recurrence and can affect the entire body including the skin, hair, and nails. The major goal of this Review is to acquire knowledge about cutting-edge approaches for treating dermatophytosis efficiently by adding antifungals to formulations based on nanocarriers in order to overcome the shortcomings of standard treatment methods. Updates on nanosystems and research developments on animal and clinical investigations are also presented. Along with the currently licensed formulations, the investigation also emphasizes novel therapies and existing therapeutic alternatives that can be used to control dermatophytosis. The Review also summarizes recent developments on the prevalence, management approaches, and disadvantages of standard dosage types. There are a number of therapeutic strategies for the treatment of dermatophytosis that have good clinical cure rates but also drawbacks such as antifungal drug resistance and unfavorable side effects. To improve therapeutic activity and get around the drawbacks of the traditional therapy approaches for dermatophytosis, efforts have been described in recent years to combine several antifungal drugs into new carriers. These formulations have been successful in providing improved antifungal activity, longer drug retention, improved effectiveness, higher skin penetration, and sustained drug release.

Hydroxychloroquine sulfate: A novel treatment for lipin-1 deficiency?

BACKGROUND

Lipin-1 deficiency is a life-threatening disease that causes severe rhabdomyolysis (RM) and chronic symptoms associated with oxidative stress. In the absence of treatment, Hydroxychloroquine sulfate (HCQ) was administered to patients off label use on a compassionate basis in order to improve their physical conditions.

METHODS

Eleven patients with LPIN1 mutations were treated with HCQ. Clinical and biological efficacy and tolerance were assessed, including pain and quality of life, physical capacities, cardiopulmonary parameters, creatine kinase levels and plasma proinflammatory cytokines. To explore a dose-dependent effect of HCQ, primary myoblasts from 4 patients were incubated with various HCQ concentrations in growth medium (GM) or during starvation (EBSS medium) to investigate autophagy and oxidative stress.

FINDINGS

Under HCQ treatment, patient physical capacities improved. Abnormal cardiac function and peripheral muscle adaptation to exercise were normalized. However, two patients who had the highest mean blood HCQ concentrations experienced RM. We hypothesized that HCQ exerts deleterious effects at high concentrations by blocking autophagy, and beneficial effects on oxidative stress at low concentrations. We confirmed in primary myoblasts from 4 patients that high in vitro HCQ concentration (10 µM) but not low concentration (1 µM and 0.1 µM) induced autophagy blockage by modifying endolysosomal pH. Low HCQ concentration (1 µM) prevented reactive oxygen species (ROS) and oxidized DNA accumulation in myoblasts during starvation.

INTERPRETATION

HCQ improves the condition of patients with lipin-1 deficiency, but at low concentrations. In vitro, 1 µM HCQ decreases oxidative stress in myoblasts whereas higher concentrations have a deleterious effect by blocking autophagy.

Interaction between endothelial cell-derived extracellular vesicles and monocytes: A potential link between vascular thrombosis and pregnancy-related morbidity in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease driven by a wide group of autoantibodies primarily directed against phospholipid-binding proteins (antiphospholipid antibodies). APS is defined by two main kinds of clinical manifestations: vascular thrombosis and pregnancy-related morbidity. In recent years, in vitro and in vivo assays, as well as the study of large groups of patients with APS, have led some authors to suggest that obstetric and vascular manifestations of the disease are probably the result of different pathogenic mechanisms. According to this hypothesis, the disease could be differentiated into two parallel entities: Vascular APS and obstetric APS. Thus, vascular APS is understood as an acquired thrombophilia in which a generalised phenomenon of endothelial activation and dysfunction (coupled with a triggering factor) causes thrombosis at any location. In contrast, obstetric APS seems to be due to an inflammatory phenomenon accompanied by trophoblast cell dysfunction. The recent approach to APS raises new issues; for instance, the mechanisms by which a single set of autoantibodies can lead to two different clinical entities are unclear. This review will address the monocyte, a cell with well-known roles in haemostasis and pregnancy, as a potential participant in vascular thrombosis and pregnancy-related morbidity in APS. We will discuss how in a steady state the monocyte-endothelial interaction occurs via extracellular vesicles (EVs), and how antiphospholipid antibodies, by inducing endothelial activation and dysfunction, may disturb this interaction to promote the release of monocyte-targeted procoagulant and inflammatory messages.

Hydroxychloroquine as an Immunomodulatory and Antithrombotic Treatment in Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an acquired highly prothrombotic disorder in which thrombo-inflammatory antiphospholipid antibodies (aPL) cause thrombosis via multiple mechanisms, including endothelial damage and activation. Obstetric complications in APS are caused by placental thrombosis, inflammation and complement activation. Anticoagulation is poorly effective in some patients especially those with triple positive aPL who are at ~30% risk of thrombosis recurrence within 10 years. Increasing therapeutic anticoagulation intensity may be beneficial but leads to excess bleeding with serious complications, such as intracerebral haemorrhage. Nonetheless, anticoagulation is still the mainstay of treatment despite the autoimmune nature of APS. The antimalarial immunomodulatory drug hydroxychloroquine (HCQ) has been used for many years for the treatment of inflammatory rheumatic diseases. HCQ has complex pleiotropic mechanisms of action upon multiple cell types. The proposed biological processes that HCQ regulates support the hypothesis that it may be a successful adjunctive treatment in the prevention of recurrent thrombosis and pregnancy complications.

Ex Vivo Modeling of the PC (Protein C) Pathway Using Endothelial Cells and Plasma: A Personalized Approach

BACKGROUND

The endothelial cell-dependent PC (protein C) pathway is critically involved in the regulation of coagulation, anti-inflammatory, and cytoprotective signaling. Its reactivity shows high interindividual variability, and it contributes to prothrombotic disorders, such as the FVL (factor V Leiden) mutation.

METHODS

Endothelial colony-forming cells (ECFCs) were isolated from heparinized peripheral blood from healthy individuals and FVL carriers. Confluent monolayers of ECFCs were overlaid with plasma, and thrombin formation was initiated by addition of tissue factor (1 pmol/L). Subsequently, thrombin and APC (activated PC) formation rates were measured over time using oligonucleotide-based enzyme capture assays. To induce downregulation of TM (thrombomodulin) expression, ECFCs were stimulated with IL-1β (interleukin 1β). In vivo APC response rates were monitored in study participants after infusion of low-dose rFVIIa (recombinant activated factor VII).

RESULTS

The median peak APC concentration was 1.12 nmol/L in experiments with IL-1β stimulated ECFCs and 3.66 nmol/L without IL-1β. Although thrombin formation rates were comparable, APC formation rates were significantly higher in FVL carriers (n=6) compared to noncarriers (n=5) as evidenced by a higher ratio between the area under the curve of APC generation to the area under the curve of thrombin generation (median 0.090 versus 0.031, P=0.017). These ex vivo results were correlated with an increased APC response to rFVIIa-induced thrombin formation in FVL carriers in vivo.

CONCLUSIONS

Patient-specific ex vivo modeling of the PC pathway was achieved using blood-derived ECFCs. The correlation between in and ex vivo APC response rates confirms that the autologous PC model accurately depicts the in vivo situation.

Targeting thromboinflammation in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disease, where persistent presence of antiphospholipid antibodies (aPL) leads to thrombotic and obstetric complications. APS is a paradigmatic thromboinflammatory disease. Thromboinflammation is a pathophysiological mechanism coupling inflammation and thrombosis, which contributes to the pathophysiology of cardiovascular disease. APS can serve as a model to unravel mechanisms of thromboinflammation and the relationship between innate immune cells and thrombosis. Monocytes are activated by aPL into a proinflammatory and procoagulant phenotype, producing proinflammatory cytokines such as tumor necrosis factor α, interleukin 6, as well as tissue factor. Important cellular signaling pathways involved are the NF-κB-pathway, mammalian target of rapamycin (mTOR) signaling, and the NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome. All of these may serve as future therapeutic targets. Neutrophils produce neutrophil extracellular traps in response to aPL, and this leads to thrombosis. Thrombosis in APS also stems from increased interaction of neutrophils with endothelial cells through P-selectin glycoprotein ligand-1. NETosis can be targeted not only with several experimental therapeutics, such as DNase, but also through the redirection of current therapies such as defibrotide and the antiplatelet agent dipyridamole. Activation of platelets by aPL leads to a procoagulant phenotype. Platelet-leukocyte interactions are increased, possibly mediated by increased levels of soluble P-selectin and soluble CD40-ligand. Platelet-directed future treatment options involve the inhibition of several platelet receptors activated by aPL, as well as mTOR inhibition. This review discusses mechanisms underlying thromboinflammation in APS that present targetable therapeutic options, some of which may be generalizable to other thromboinflammatory diseases.

Extracellular vesicles released upon stimulation with antiphospholipid antibodies: An actual direct procoagulant mechanism or a new factor in the lupus anticoagulant paradox?

Antiphospholipid antibodies (aPL) lead to a hypercoagulable state in vivo. Paradoxically, some of these autoantibodies perform as inhibitors of the coagulation cascade in vitro (a phenomenon referred to as "lupus anticoagulant"). The presence of lupus anticoagulant has been related to an increased quantity of plasma extracellular vesicles, which may constitute a direct procoagulant mechanism in antiphospholipid syndrome. This study investigates whether or not endothelial cell-derived extracellular vesicles released upon stimulation with aPL (aPL-EDEVs) are related to a higher direct coagulation activity. Using an in vitro model of endothelium, flow cytometry and a recalcified plasma-based assay, we found that the coagulation activity of aPL-EDEVs is mainly conditioned by the lupus anticoagulant-like activity of autoantibodies. Nevertheless, in the presence of β2 glycoprotein I, a cofactor of aPL during the stimulation of endothelial cells, the coagulation activity of EDEVs is restored in a mitogen-activated protein kinase kinases 1 and 2 (MEK1/2)-dependent manner. This phenomenon was especially evident when using immunoglobulins G from patients with vascular and obstetric primary antiphospholipid syndrome who manifest refractoriness to treatment. Our findings suggest that the role of aPL-EDEVs in the antiphospholipid syndrome-related hypercoagulable state may not rely on their capacity to enhance clotting directly. While β2 glycoprotein I performs as a procoagulant cofactor and restores the coagulation activity of extracellular vesicles via MEK1/2 pathway, proportionally, autoantibodies interact with aPL-EDEVs and exhaust their coagulation properties. Further analysis is required to establish whether lupus anticoagulant-like autoantibodies opsonise extracellular vesicles and whether opsonised vesicles may lead to thrombosis by indirect means.

Biologic Functions of Hydroxychloroquine in Disease: From COVID-19 to Cancer

Chloroquine (CQ) and Hydroxychloroquine (HCQ), initially utilized in the treatment of malaria, have now developed a long list of applications. Despite their clinical relevance, their mechanisms of action are not clearly defined. Major pathways by which these agents are proposed to function include alkalinization of lysosomes and endosomes, downregulation of C-X-C chemokine receptor type 4 (CXCR4) expression, high-mobility group box 1 protein (HMGB1) inhibition, alteration of intracellular calcium, and prevention of thrombus formation. However, there is conflicting data present in the literature. This is likely the result of the complex overlapping pathways between these mechanisms of action that have not previously been highlighted. In fact, prior research has focused on very specific portions of particular pathways without describing these in the context of the extensive CQ/HCQ literature. This review summarizes the detailed data regarding CQ/HCQ's mechanisms of action while also providing insight into the overarching themes. Furthermore, this review provides clinical context to the application of these diverse drugs including their role in malaria, autoimmune disorders, cardiovascular disease, thrombus formation, malignancies, and viral infections.

Connexin 43 Expression in Cutaneous Biopsies of Lupus Erythematosus

INTRODUCTION

Gap junctions are channels between adjacent cells formed by connexins (Cxs). Cxs also form hemichannels that connect the cell with its extracellular milieu. These channels allow the transport of ions, metabolites, and small molecules; therefore, Cxs, and more specifically, connexin (Cx) 43 has been demonstrated to be in control of several crucial events such as inflammation and cell death.

MATERIAL AND METHODS

We examined the immunostaining of Cx43 in the endothelia of the cutaneous blood vessels of biopsies from 28 patients with several variants of lupus erythematosus.

RESULTS

In 19 cases (67.86%), staining of more than half of the dermal vessels including both vessels of the papillary and of the reticular dermis was identified. Only in 4 cases (14.28%), less than 25% of the vessels in the biopsy showed expression of the marker.

CONCLUSIONS

Our results suggest a role of Cx43 in regulating the endothelial activity in lupus erythematosus, which also opens a door for targeted therapeutic options.

Cardiovascular disease risk and pathogenesis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) often features extensive cardiovascular (CV) comorbidity and patients with SLE are at significantly increased risk of CV event occurrence and CV-related mortality. While the specific mechanisms leading to this increased cardiovascular disease (CVD) risk remain to be fully characterized, this heightened risk cannot be fully explained by traditional CV risk factors and is likely driven by immunologic and inflammatory features of SLE. Widespread innate and adaptive immune dysregulation characterize SLE, and factors including excessive type I interferon burden, inappropriate formation and ineffective clearance of neutrophil extracellular traps, and autoantibody formation have been linked to clinical and metabolic features impacting CV risk in SLE and may represent pathogenic drivers of SLE-related CVD. Indeed, functional and phenotypic aberrations in almost every immune cell type are present in SLE and may impact CVD progression. As understanding of the contribution of SLE-specific factors to CVD in SLE improves, improved screening and monitoring of CV risk alongside development of therapeutic treatments aimed at prevention of CVD in SLE patients are required and remain the focus of several ongoing studies and lines of inquiry.

Cardiovascular disease risk and pathogenesis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) often features extensive cardiovascular (CV) comorbidity and patients with SLE are at significantly increased risk of CV event occurrence and CV-related mortality. While the specific mechanisms leading to this increased cardiovascular disease (CVD) risk remain to be fully characterized, this heightened risk cannot be fully explained by traditional CV risk factors and is likely driven by immunologic and inflammatory features of SLE. Widespread innate and adaptive immune dysregulation characterize SLE, and factors including excessive type I interferon burden, inappropriate formation and ineffective clearance of neutrophil extracellular traps, and autoantibody formation have been linked to clinical and metabolic features impacting CV risk in SLE and may represent pathogenic drivers of SLE-related CVD. Indeed, functional and phenotypic aberrations in almost every immune cell type are present in SLE and may impact CVD progression. As understanding of the contribution of SLE-specific factors to CVD in SLE improves, improved screening and monitoring of CV risk alongside development of therapeutic treatments aimed at prevention of CVD in SLE patients are required and remain the focus of several ongoing studies and lines of inquiry.

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.

Antiphospholipid Antibodies From Women With Pregnancy Morbidity and Vascular Thrombosis Induce Endothelial Mitochondrial Dysfunction, mTOR Activation, and Autophagy

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombosis and pregnancy morbidity (PM) obstetric events together with persistent high titers of circulating antiphospholipid antibodies (aPL). Several mechanisms that explain the development of thrombosis and PM in APS include the association of aPL with alterations in the coagulation cascade and inflammatory events. Other mechanisms disturbing cellular homeostases, such as mitochondrial dysfunction, autophagy, and cell proliferation, have been described in other autoimmune diseases. Therefore, the objective of this study was to investigate the impact of aPL from different patient populations on endothelial cell mitochondrial function, activation of the mammalian target of rapamycin (mTOR) and autophagy pathways, and cellular growth. Using an in vitro model, human umbilical vein endothelial cells (HUVECs) were treated with polyclonal immunoglobulin G (IgG) purified from the serum of women with both PM and vascular thrombosis (PM/VT), with VT only (VT), or with PM and non-criteria aPL (seronegative-obstetric APS, SN-OAPS). We included IgG from women with PM without aPL (PM/aPL-) and healthy women with previous uncomplicated pregnancies (normal human serum, NHS) as control groups. Mitochondrial function, mTOR activation, autophagy, and cell proliferation were evaluated by Western blotting, flow cytometry, and functional assays. IgG from women with PM/VT increased HUVEC mitochondrial hyperpolarization and activation of the mTOR and autophagic pathways, while IgG from patients with VT induced endothelial autophagy and cell proliferation in the absence of elevated mTOR activity or mitochondrial dysfunction. IgG from the SN-OAPS patient group had no effect on any of these HUVEC responses. In conclusion, aPL from women with PM and vascular events induce cellular stress evidenced by mitochondrial hyperpolarization and increased activation of the mTOR and autophagic pathways which may play a role in the pathogenesis of obstetric APS.

Immune Thrombocytopenia in Antiphospholipid Syndrome: Is It Primary or Secondary?

Antiphospholipid syndrome (APS) is frequently associated with thrombocytopenia, in most cases mild and in the absence of major bleedings. In some patients with a confirmed APS diagnosis, secondary immune thrombocytopenia (ITP) may lead to severe thrombocytopenia with consequent major bleeding. At the same time, the presence of antiphospholipid antibodies (aPL) in patients with a diagnosis of primary ITP has been reported in several studies, although with some specific characteristics especially related to the variety of antigenic targets. Even though it does not enter the APS defining criteria, thrombocytopenia should be regarded as a warning sign of a “high risk” APS and thus thoroughly evaluated. The presence of aPL in patients with ITP should be assessed as well to stratify the risk of paradoxical thrombosis. In detail, besides the high hemorrhagic risk in secondary thrombocytopenia, patients with a co-diagnosis of APS or only antibodies are also at risk of arterial and venous thrombosis. In this narrative review, we discuss the correlation between APS and ITP, the mechanisms behind the above-reported entities, in order to support clinicians to define the most appropriate treatment strategy in these patients, especially when anticoagulant or antiplatelet agents may be needed.

Hydroxychloroquine and Mortality Among Patients With Systemic Lupus Erythematosus in the General Population

OBJECTIVE

Hydroxychloroquine (HCQ) has been associated with improved survival among patients with systemic lupus erythematosus (SLE) from tertiary referral centers. We aimed to determine the potential impact of HCQ use on the risk of mortality among SLE patients in the general population.

METHODS

We conducted a nested case-control study within an incident SLE cohort from the entire population of British Columbia, Canada. Deceased patients were matched with up to 3 living controls by age, sex, and SLE disease duration. HCQ exposure was categorized by the time between the last HCQ prescription date covered (i.e., end of supply) and the index date (i.e., death date) as current (<30 days), recent (30-365 days), remote (>365 days), or never used. We used conditional logistic regression to assess the risk of all-cause mortality associated with current or recent HCQ exposure compared with remote HCQ users.

RESULTS

Among 6,241 patients with incident SLE, we identified 290 deceased patients and 502 matched SLE controls. Adjusted odd ratios for all-cause mortality were 0.50 (95% confidence interval [95% CI] 0.30-0.82) for current users and 2.47 (95% CI 1.21-5.05) for recent users compared with remote users. Associations were similar in subgroups according to SLE duration (≤5 years versus >5 years).

CONCLUSION

Our general population data support a substantial survival benefit associated with current HCQ use. Increased mortality among patients who had discontinued HCQ recently could be due to a sick stopper effect or the loss of actual HCQ benefits.

Effect of hydroxychloroquine on antiphospholipid antibodies-inhibited endometrial angiogenesis

BACKGROUND

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic events and/or pregnancy morbidity (≥3 recurrent early miscarriage or fetal death or a prematurity <34 weeks of gestation) with persistently positive antiphospholipid antibodies (aPLs). It is reported that aPLs damage the placental tissue by binding to β2-glycoprotein I (β2GPI) on the surface of trophoblast and endothelial cells. Hydroxychloroquine (HCQ) is considered to be beneficial in the treatment of obstetrical APS and shown to restore the aPL-inhibited invasion and differentiation of trophoblast. However, not enough evidence exists regarding the effect of HCQ on endometrial angiogenesis. The aim of our study was to assess whether HCQ has an effect on aPL-inhibited endothelial angiogenesis.

METHODS

In this research, to explore the effect of HCQ for angiogenesis, we investigated: (1) Human umbilical vein endothelial cells (HUVECs) viability by CCK-8; (2) HUVECs migration by wound healing; (3) HUVEC angiogenesis by Matrigel assay in vitro; (4) mRNA expression of MMP-2 and VEGF by real-time quantitative Polymerase Chain Reaction (RT-PCR); (5) protein expression of VEGF, MMP-2 by western blot.

RESULTS

We found that HCQ treatment significantly restored the expression of aPL-inhibited VEGF and MMP-2. HCQ restored aPL-inhibited HUVEC proliferation, migration, and angiogenesis in vitro.

CONCLUSION

In conclusion, aPLs inhibit HUVECs angiogenesis, however, HCQ can restore the effect of aPL-inhibited HUVECs migration and angiogenesis in vitro, demonstrating its beneficial therapeutic role in obstetrical APS.

[Thrombin generation assay in autoimmune disease]

Thrombin generation assay (TGA) is a useful tool to evaluate the initiation, propagation and inhibition of coagulation. TGA is a global test that is used to assess hemorrhagic risk in hemophilia patients, but it can also be used to study hypercoagulable states. The interest of TGA is to screen for cardiovascular risk, which is regularly associated with autoimmune disease (AID) such as antiphospholipid syndrome. Indeed, TGA has been used to evaluate hypercoagulability in patients with antiphospholipid syndrome treated with rivaroxaban versus warfarin. In other AIDs without thrombotic events, TGA measurement is elevated, mainly in rheumatoid arthritis (RA), systemic lupus erythematosus and Behçet's disease. These findings in RA are correlated with the inflammatory activity of the disease. In systemic lupus erythematosus and Behçet's disease, TGA appears to reflect disease activity. In conclusion, TGA remains relatively under used in the clinical evaluation of AID, but it could play a greater role in the evaluation of certain potentially thrombogenic treatments in AID. Finally, TGA helps measuring AID activity, due to the clearlink between coagulation and inflammation, despite some limitations of interpretation mainly due to a lack of standardization.

Hypercoagulability Evaluation in Antiphospholipid Syndrome without Anticoagulation Treatment with Thrombin Generation Assay: A Preliminary Study

Antiphospholipid syndrome (APS) is associated with thrombotic events (tAPS) and/or obstetrical morbidity (oAPS), with persisting antiphospholipid antibodies (aPL). Despite an update of aPL in 2006, several patients had typical clinical events without the classical biological criteria. The aim of our study was to evaluate the hypercoagulability state with both thrombin generation (TG) profiles and activated protein C resistance (aPCR) in different types of APS. Methods: We retrospectively included 41 patients with Sydney criteria classification (tAPS, oAPS) and no clinical manifestation of APS with persistent aPL (biological APS). A thrombin generation assay was performed with a Fluoroskan Ascent fluorometer in platelet-poor plasma (PPP). Activated protein C resistance was measured as a ratio: ETP_+aPC/ETP_-aPC × 100. Results: Thrombotic APS and oAPS had an increase of global thrombin generation (ETP_control = 808 nM.min (756–853) vs. 1265 nM.min (956–1741) and 1863 nM.min (1434–2080), respectively) (Peak_control = 78 nM (74–86) vs. 153 nM (109–215) and 254 nM.min (232–289), respectively). Biological APS had only a lag time increase (T_control = 4.89 ± 1.65 min vs. 13.6 ± 3.9 min). An increased aPCR was observed in tAPS (52.7 ± 16.4%), oAPS (64.1 ± 14.6%) as compared to the control group (27.2 ± 13.8%). Conclusion: Our data suggest an increase of thrombin generation in thrombotic and obstetrical APS and no hypercoagulable states in patients with biological APS. The study of a prospective and a larger controlled cohort could determine the TGA useful for APS monitoring and could confirm an aPCR evaluation in PPP.

Investigation of Coagulation Biomarkers to Assess Clinical Deterioration in SARS-CoV-2 Infection

Since December 2019, a pandemic caused by a new coronavirus has spread to more than 170 countries around the world. Worsening infected patients requiring intensive care unit (ICU) admission associated with 30% of mortality. A part of worsening is induced by hemostasis deregulation. The aim of this study was to investigate the association of coagulation activation in COVID-19 progression. Thirty-five of the 99 patients got clinically worse. The final model of the logistic regression analysis revealed that O₂ requirement (RR = 7.27 [1.50–19.31]), monocytes below 0.2G/L (RR = 2.88 [1.67–3.19]), fibrinogen levels (RR = 1.45 [1.17–1.82] per g/L increase), prothrombin fragments 1+2 higher than 290 pM (RR = 2.39 [1.20–3.30]), and thrombin peak (RR = 1.28 [1.03–1.59] per 50 nM increase) were associated with an increased risk of clinical worsening. A fibrinogen level threshold of 5.5 g/L, a thrombin peak measurement threshold of 99 pM, and O₂ requirement associated with clinical outcome in more than 80% of our cohort. In conclusion, we identified fibrinogen and thrombin peak at admission as coagulation biomarkers associated with an increased risk of ICU admission or death. This finding allows initiating steroids and triage for worsening patients. Our results should therefore be considered as exploratory and deserve confirmation.

How I treat anticoagulant-refractory thrombotic antiphospholipid syndrome

The standard treatment of thrombotic antiphospholipid syndrome (APS) is lifelong oral anticoagulation with a vitamin K antagonist (VKA), generally warfarin. A minority of patients with APS rethrombose despite seemingly adequate anticoagulation. These patients are deemed anticoagulant refractory. The management of anticoagulant-refractory APS is largely empirical and extrapolated from other clinically similar situations. Further options include increased VKA anticoagulation intensity or alternative antithrombotic strategies, including low-molecular-weight heparin, fondaparinux, the addition of antiplatelet therapy, and consideration of vascular options. Patients with anticoagulant-refractory thrombotic APS may have APS-associated thrombocytopenia, which necessitates balancing the risk of recurrent thrombosis vs bleeding to achieve adequate anticoagulation. The multiple mechanisms involved in the generation of the thrombotic phenotype in APS suggest that anticoagulation alone may not control thrombosis. Thus, other modalities, including adjunctive treatment (hydroxychloroquine, statins, and vitamin D) for APS-related thrombosis, merit consideration, as do immunomodulatory therapy and complement inhibition. Patients with APS may have coexistent systemic lupus erythematosus, which adds to the complexity of managing their thromboembolic disease. However, with attention to detail and judicious application of the limited data, it is possible to minimize the morbidity resulting from anticoagulant-refractory thrombotic APS. Multicenter studies are required to guide the sequence of interventions and their comparative efficacy in patients with anticoagulant-refractory thrombotic APS.

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.

Understanding the Pathophysiology of Thrombotic APS through Animal Models

Antiphospholipid syndrome (APS) is a leading acquired cause of thrombotic events, with a notable tendency to promote thrombosis in vascular beds of all sizes, including both arterial and venous circuits. While pathogenic antiphospholipid antibodies circulate at relatively stable levels in blood, thrombosis tends to manifest as discrete and acute events, suggesting the requirement for a “second hit.” While this two-hit model is generally accepted, much remains to be learned about exactly how antiphospholipid antibodies predispose to thrombosis in vivo and exactly how this predisposition interacts with the second hit. To this end, investigators have turned to animal models. Numerous approaches for modeling APS in animals have been described to date, each with potential advantages and disadvantages. This review will attempt to describe the most common APS models employed so far while discussing some pros and cons of each. Mechanisms of thrombotic APS that have thus far been explored in animal models will also be briefly addressed.

Coronavirus disease 2019 (COVID-19) and autoimmunity

The coronavirus 2019 pandemic (coronavirus disease, COVID-19), etiologically related to the SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus-2), has once again reawakened healthcare professionals’ interest towards new clinical and conceptual issues of human immunology and immunopathology. An unprecedented number of clinical trials and fundamental studies of epidemiology, virology, immunology and molecular biology, of the COVID-19 clinical course polymorphism and pharmacotherapy have been conducted within one year since the outbreak of 2019 pandemic, bringing together scientists of almost all biological and physicians of almost all medical specialties. Their joint efforts have resulted in elaboration of several types of vaccines against SARS-CoV-2 infection and, in general, fashioning of more rational approaches to patient management. Also important for COVID-19 management were all clinical trials of biologics and “targeted” anti-inflammatory drugs modulating intracellular cytokine signaling, which have been specifically developed for treatment immune-mediated inflammatory rheumatic disease (IMIRDs) over the past 20 years. It became obvious after a comprehensive analysis of the entire spectrum of clinical manifestations and immunopathological disorders in COVID-19 is accompanied by a wide range of extrapulmonary clinical and laboratory disorders, some of which are characteristic of IMIRDs and other autoimmune and auto-in-flammatory human diseases. All these phenomena substantiated the practice of anti-inflammatory drugs repurposing with off-label use of specific antirheumatic agents for treatment of COVID-19. This paper discusses potential use of glucocorticoids, biologics, JAK inhibitors, etc., blocking the effects of pro-inflammatory cytokines for treatment of COVID-19.

Can hydroxychloroquine be protective against COVID-19-associated thrombotic events ?

Although SARS-CoV-2 is considered a lung-tropic virus, severe COVID-19 is not just a viral pulmonary infection, clinically it is a multi-organ pathology with major coagulation abnormalities and thromboembolism events. Recently, antiphospholipid (aPL) antibodies were found increased in a large number of COVID-19 patients. Elevated aPL have been well documented in antiphospholipid syndrome (APS), a systemic autoimmune disorder characterized by recurrent venous or arterial thrombosis and/or obstetrical morbidity. Among treatment regimen of APS, hydroxychloroquine (HCQ) is one of the molecules proposed in the primary prevention of thrombosis and obstetrical morbidity in those patients. Due to its antithrombotic properties documented in APS therapy, HCQ could be considered a good candidate for the prevention of thrombotic events in COVID-19 patients in association with anticoagulant and its repurposing deserves further evaluation.

Formulation and stability study of hydroxychloroquine sulfate oral suspensions

Hydroxychloroquine is an antimalarial drug indicated in the treatment of acute attacks of malaria due to Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum. It is also used for the treatment of rheumatoid arthritis, discoid and systemic lupus erythematosus, and more recently proposed in COVID-19 therapy. Hydroxychloroquine is only available in tablets which are not easy to administer for pediatric and geriatric patients, and patients unable to swallow such as patients found in intensive care units. The aim of this work was to develop and optimize a ready to use liquid hydroxychloroquine formulation and to carry out the corresponding chemical and microbiological stability studies. The formulation was evaluated for ease of preparation, physical properties, and palatability. Its stability was performed at ambient temperature and under refrigeration. After 6 months of stability testing, the results showed no pH change, no drug loss, no microbial development, and no visual change. The formulation, employing excipients in a range that EMA has recommended, showed chemical and microbiological stability for at least 6 months even in the worst storage conditions.

Comorbidities in rheumatic diseases need special consideration during the COVID-19 pandemic

Comorbidities in rheumatic and musculoskeletal diseases (RMDs) not only increase morbidity and mortality but also confound disease activity, limit drug usage and increase chances of severe infections or drug-associated adverse effects. Most RMDs lead to accelerated atherosclerosis and variable manifestations of the metabolic syndrome. Literature on COVID-19 in patients with RMDs, and the effects of various comorbidities on COVID-19 was reviewed. The initial data of COVID-19 infections in RMDs have not shown an increased risk for severe disease or the use of different immunosuppression. However, there are some emerging data that patients with RMDs and comorbidities may fare worse. Various meta-analyses have reiterated that pre-existing hypertension, cardiovascular disease, stroke, diabetes, chronic kidney disease, heart failure, lung disease or obesity predispose to increased COVID-19 mortality. All these comorbidities are commonly encountered in the various RMDs. Presence of comorbidities in RMDs pose a greater risk than the RMDs themselves. A risk score based on comorbidities in RMDs should be developed to predict severe COVID-19 and death. Additionally, there should be active management of such comorbidities to mitigate these risks. The pandemic must draw our attention towards, and not away from, comorbidities.

Efficacy of chloroquine or hydroxychloroquine in COVID-19 patients: a systematic review and meta-analysis

OBJECTIVES

Clinical studies of chloroquine (CQ) and hydroxychloroquine (HCQ) in COVID-19 disease reported conflicting results. We sought to systematically evaluate the effect of CQ and HCQ with or without azithromycin on outcomes of COVID-19 patients.

METHODS

We searched multiple databases, preprints and grey literature up to 17 July 2020. We pooled only adjusted-effect estimates of mortality using a random-effect model. We summarized the effect of CQ or HCQ on viral clearance, ICU admission/mechanical ventilation and hospitalization.

RESULTS

Seven randomized clinical trials (RCTs) and 14 cohort studies were included (20 979 patients). Thirteen studies (1 RCT and 12 cohort studies) with 15 938 hospitalized patients examined the effect of HCQ on short-term mortality. The pooled adjusted OR was 1.05 (95% CI 0.96-1.15, I2 = 0%). Six cohort studies examined the effect of the HCQ+azithromycin combination with a pooled adjusted OR of 1.32 (95% CI 1.00-1.75, I2 = 68.1%). Two cohort studies and four RCTs found no effect of HCQ on viral clearance. One small RCT demonstrated improved viral clearance with CQ and HCQ. Three cohort studies found that HCQ had no significant effect on mechanical ventilation/ICU admission. Two RCTs found no effect for HCQ on hospitalization risk in outpatients with COVID-19.

CONCLUSIONS

Moderate certainty evidence suggests that HCQ, with or without azithromycin, lacks efficacy in reducing short-term mortality in patients hospitalized with COVID-19 or risk of hospitalization in outpatients with COVID-19.

Cardiac Toxicity of Chloroquine or Hydroxychloroquine in Patients With COVID-19: A Systematic Review and Meta-regression Analysis

Objective

To systematically review the literature and to estimate the risk of chloroquine (CQ) and hydroxychloroquine (HCQ) cardiac toxicity in patients with coronavirus disease 2019 (COVID-19).

Methods

We searched multiple data sources including PubMed/MEDLINE, Ovid Embase, Ovid EBM Reviews, Scopus, and Web of Science and medrxiv.org from November 2019 through May 27, 2020. We included studies that enrolled patients with COVID-19 treated with CQ or HCQ, with or without azithromycin, and reported on cardiac toxic effects. We performed a meta-analysis using the arcsine transformation of the different incidences.

Results

A total of 19 studies with a total of 5652 patients were included. The pooled incidence of torsades de pointes arrhythmia, ventricular tachycardia, or cardiac arrest was 3 per 1000 (95% CI, 0-21; I ² =96%) in 18 studies with 3725 patients. Among 13 studies of 4334 patients, the pooled incidence of discontinuation of CQ or HCQ due to prolonged QTc or arrhythmias was 5% (95% CI, 1-11; I ² =98%). The pooled incidence of change in QTc from baseline of 60 milliseconds or more or QTc of 500 milliseconds or more was 9% (95% CI, 3-17; I ² =97%). Mean or median age, coronary artery disease, hypertension, diabetes, concomitant QT-prolonging medications, intensive care unit admission, and severity of illness in the study populations explained between-studies heterogeneity.

Conclusion

Treatment of patients with COVID-19 with CQ or HCQ is associated with an important risk of drug-induced QT prolongation and relatively higher incidence of torsades de pointes, ventricular tachycardia, or cardiac arrest. Therefore, these agents should not be used routinely in the management of COVID-19 disease. Patients with COVID-19 who are treated with antimalarials for other indications should be adequately monitored.

Cardiovascular Protection of Hydroxychloroquine in Patients with Sjögren's Syndrome

Sjögren’s syndrome (SS) is a chronic systemic inflammation disease with clinical presentation of dry eye, dry mouth, and polyarthralgia. Active inflammation is associated with an increased risk of associated arterial stiffness or subclinical atherosclerosis-related cardiovascular events. We used the longitudinal health insurance database of Taiwan, which includes one million participants, to evaluate the relationship between the clinical medication of hydroxychloroquine (HCQ) and the development of coronary artery disease (CAD). In total, 1674 patients with SS receiving HCQ medication were included after exclusion for previous CAD. Altogether, 1142 SS patients were included for evaluation after follow-up for more than one year. After adjusting for age, gender, medications, and chronic comorbidities, a significantly decreased hazard ratio (HR) for developing CAD was found among SS patients with higher medication possession ratio (MPR) of HCQ (HR = 0.49, 95% confidence interval, CI: 0.26–0.94) when compared with low MPR of HCQ. A low HR for CAD was observed in SS patients with a high cumulative dose of at least 100,267 mg of HCQ (HR = 0.25, 95% CI: 0.09–0.66). Long-term HCQ therapy may decrease the HR of CAD in SS patients. The significant cardiovascular protective effect of HCQ therapy was observed in our study.

Endothelial Colony-Forming Cells from Idiopathic Pulmonary Fibrosis Patients Have a High Procoagulant Potential

Idiopathic pulmonary fibrosis (IPF) is a severe, progressive and irreversible lung disease constantly associated with a major vascular remodeling process. Endothelial colony-forming cells (ECFCs) are human vasculogenic cells proposed as a cell therapy product or liquid biopsy in vascular disorders. Since the link between IPF and thrombosis has been largely proposed, the aim of our study was to explore hypercoagulability states in ECFCs from patients with IPF. We performed Thrombin generation assay (TGA) in cord blood (CB)-ECFCs, peripheral blood (PB)-ECFCs and IPF-ECFCs. Endogenous thrombin potential and peak were higher in IPF-ECFCs compared to CB-ECFCs and PB-ECFCs. As thrombin generation in ECFCs was increased, we evaluated anticoagulant proteins expressed on ECFCs membrane and identified thrombomodulin and EPCR. We found a significant decrease of both anticoagulant proteins at membrane using flow cytometry. This study is the first to examine ECFC thrombin generation in IPF. This new finding strongly argues for a role of ECFC in IPF pathophysiology and thrombotic related disorders in IPF. Graphical Abstract.

Coronavirus disease 2019 (COVID-19) and immune-mediated inflammatory rheumatic diseases: at the crossroads of thromboinflammation and autoimmunity

Inflammation and coagulation are key basic mechanism of protection against all potentially pathogenic mechanical and biological factors targeting human organism from inner and outer environment. On the other hand, uncontrolled inflammation results in hypercoagulation, inhibition of anticoagulation and alteration of mechanisms responsible for resolution of inflammation, while production of “procoagulant” mediators (thrombin, tissue factor and others), activation of platelets and of vascular endothelial cells maintains inflammation. All factors taken together serve as the basis for a pathological process called thromboinflammation or immunothrombosis. Currently thromboinflammation is considered in the broad sense as a universal pathogenetic mechanism of numerous widespread acute and chronic conditions, including immune-mediated (autoimmune) inflammatory rheumatic diseases, oftentimes complicated by severe irreversible damage to vital organs. Thromboinflammation gained specific attention during СОVID-19 (coronavirus disease 2019) pandemic, caused by SARS-Cov-2 (severe acute respiratory syndrome Coronavirus-2). COVID-19 is considered currently as systemic thromboinflammation syndrome, manifesting via generalized thrombosis of arterial and venous macro- and microvasculature, termed as COVID-19-coagulopathy. The paper discusses common pathogenetic coagulopathy mechanisms in COVID-19 and immune-mediated (autoimmune) inflammatory rheumatic diseases (IMRDs), associated with overproduction of antiphospholipid antibodies, activation of the complement system, and dis-regulated synthesis of proinflammatory cytokines, etc. Delineating the autoimmune subtype of thromboinflammation, identification of genetic (i.e., genes encoding the complement system and others) and molecular-biologic biomarkers associated with higher occurrence of COVID-19-coagulopathy are the most relevant undertakings for the current practice. Gaining insights into mechanisms of thromboinflammation and converting them into potential pharmacotherapies of IMDs would facilitate and accelerate the drafting of effective therapeutic strategies for COVID-19. 

Benefits and adverse effects of hydroxychloroquine, methotrexate and colchicine: searching for repurposable drug candidates

Repurposing of antirheumatic drugs has garnered global attention. The aim of this article is to overview available evidence on the use of widely used antirheumatic drugs hydroxychloroquine, methotrexate and colchicine for additional indications. Hydroxychloroquine has endothelial stabilizing and anti-thrombotic effects. Its use has been explored as an adjunctive therapy in refractory thrombosis in antiphospholipid syndrome. It may also prevent recurrent pregnancy losses in the absence of antiphospholipid antibodies. Hydroxychloroquine favourably modulates atherogenic lipid and glycaemic profiles. Methotrexate has been tried for modulation of cardiovascular events in non-rheumatic clinical conditions, although a large clinical trial failed to demonstrate a benefit. Colchicine has been shown to successfully reduce the risk of recurrent cardiovascular events in a large multicentric trial. Potential antifibrotic effects of colchicine require further exploration. Hydroxychloroquine, methotrexate and colchicine are also being tried at different stages of the ongoing Coronavirus Disease 19 (COVID-19) pandemic for prophylaxis and treatment. While the use of these agents is being diversified, their adverse effects should be timely diagnosed and prevented. Hydroxychloroquine can cause retinopathy and rarely cardiac and auditory toxicity, retinopathy being dose and time dependent. Methotrexate can cause transaminitis, cytopenias and renal failure, particularly in acute overdoses. Colchicine can rarely cause myopathies, cardiomyopathy, cytopenias and transaminitis. Strong evidence is warranted to keep balance between benefits of repurposing these old antirheumatic drugs and risk of their adverse effects.

A pharmacological perspective of chloroquine in SARS-CoV-2 infection: An old drug for the fight against a new coronavirus?

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is having serious consequences on health and the economy worldwide. All evidence-based treatment strategies need to be considered to combat this new virus. Drugs need to be considered on scientific grounds of efficacy, safety and cost. Chloroquine (CQ) and hydroxychloroquine (HCQ) are old drugs used in the treatment of malaria. Moreover, their antiviral properties have been previously studied, including against coronaviruses, where evidence of efficacy has been found. In the current race against time triggered by the COVID-19 pandemic, the search for new antivirals is very important. However, consideration should be given to old drugs with known anti-coronavirus activity, such as CQ and HCQ. These could be integrated into current treatment strategies while novel treatments are awaited, also in light of the fact that they display an anticoagulant effect that facilitates the activity of low-molecular-weight heparin, aimed at preventing acute respiratory distress syndrome (ARDS)-associated thrombotic events. The safety of CQ and HCQ has been studied for over 50 years, however recently published data raise concerns for cardiac toxicity of CQ/HCQ in patients with COVID-19. This review also re-examines the real information provided by some of the published alarming reports, although concluding that cardiac toxicity should in any case be stringently monitored in patients receiving CQ/HCQ.

It is time to drop hydroxychloroquine from our COVID-19 armamentarium

Chloroquine (CQ) and hydroxychloroquine (HCQ) were among the first drugs repurposed for the treatment of SARS-CoV-2 infection. A few in vitro studies confirmed that both drugs exhibited dose dependent anti-SARS-CoV-2 activities. These observations and the encouraging results from early poorly conducted observational studies created a major hype about the therapeutic potential of these drugs in the treatment of COVID-19 disease. This was further catalyzed by media and political influences leading to a widespread use of these agents. Subsequent randomized trials revealed lack of efficacy of these agents in improving the outcomes of COVID-19 or in preventing infection in post-exposure prophylaxis studies. Nevertheless, many ongoing trials continue to actively recruit tens of thousands of patients to receive HCQ worldwide. In this perspective, we address the possible mechanisms behind the lack of efficacy and the increased risk of cardiac toxicity of HCQ in COVID-19 disease. For the lack of efficacy, we discuss the fundamental differences of treatment initiation between in vitro and in vivo studies, the pitfalls of the pharmacological calculations of effective blood drug concentrations and related dosing regimens, and the possible negative effect of HCQ on the antiviral type-I interferon response. Although it has been repeatedly claimed that HCQ has a longstanding safety track record for many decades in use, we present counterarguments for this contention due to disease-drug and drug-drug interactions. We discuss the molecular mechanisms and the cumulative epidemiological evidence of HCQ cardiac toxicity.

Evaluation of different commercial antibodies for their ability to detect human and mouse tissue factor by western blotting

BACKGROUND

Western blotting is used to measure protein expression in cells and tissues. Appropriate interpretation of resulting data is contingent upon antibody validation.

OBJECTIVES

We assessed several commercial anti-human and anti-mouse tissue factor (TF) antibodies for their ability to detect TF by western blotting.

MATERIAL AND METHODS

We used human pancreatic cancer cell lines expressing different levels of TF and a mouse pancreatic cancer cell line expressing TF with a matched knockout derivative.

RESULTS

Human and mouse TF protein detected by western blotting correlated with levels of TF mRNA in these cell lines. The apparent molecular weight of TF is increased by N-linked glycosylation and, as expected, deglycosylation decreased the size of TF based on western blotting. We found that four commercial anti-human TF antibodies detected TF in a TF-positive cell line HPAF-II whereas no signal was observed in a TF-negative cell line MIA PaCa-2. More variability was observed in detecting mouse TF. Two anti-mouse TF antibodies detected mouse TF in a TF-positive cell line and no signal was observed in a TF knockout cell line. However, a third anti-mouse TF antibody detected a nonspecific protein in both the mouse TF-positive and TF-negative cell lines. Two anti-human TF antibodies that are claimed to cross react with mouse TF either recognized a nonspecific band or did not detect mouse TF.

DISCUSSION

Our results indicate that there is a range in quality of commercial anti-TF antibodies.

CONCLUSION

We recommend that all commercial antibodies should be validated to ensure that they detect TF.

The possible mechanisms of action of 4-aminoquinolines (chloroquine/hydroxychloroquine) against Sars-Cov-2 infection (COVID-19): A role for iron homeostasis?

The anti-malarial drugs chloroquine (CQ) and primarily the less toxic hydroxychloroquine (HCQ) are currently used to treat autoimmune diseases for their immunomodulatory and anti-thrombotic properties. They have also been proposed for the treatment of several viral infections, due to their anti-viral effects in cell cultures and animal models, and, currently, for the treatment of coronavirus disease 2019 (COVID-19), the pandemic severe acute respiratory syndrome caused by coronavirus 2 (Sars-Cov-2) infection that is spreading all over the world. Although in some recent studies a clinical improvement in COVID-19 patients has been observed, the clinical efficacy of CQ and HCQ in COVID-19 has yet to be proven with randomized controlled studies, many of which are currently ongoing, also considering pharmacokinetics, optimal dosing regimen, therapeutic level and duration of treatment and taking into account patients with different severity degrees of disease. Here we review what is currently known on the mechanisms of action of CQ and HCQ as anti-viral, anti-inflammatory and anti-thrombotic drugs and discuss the up-to-date experimental evidence on the potential mechanisms of action of CQ/HCQ in Sars-Cov2 infection and the current clinical knowledge on their efficacy in the treatment of COVID-19 patients. Given the role of iron in several human viral infections, we also propose a different insight into a number of CQ and HCQ pharmacological effects, suggesting a potential involvement of iron homeostasis in Sars-Cov-2 infection and COVID-19 clinical course.

Hydroxychloroquine in rheumatic autoimmune disorders and beyond

Initially used as antimalarial drugs, hydroxychloroquine (HCQ) and, to a lesser extent, chloroquine (CQ) are currently being used to treat several diseases. Due to its cost‐effectiveness, safety and efficacy, HCQ is especially used in rheumatic autoimmune disorders (RADs), such as systemic lupus erythematosus, primary Sjögren's syndrome and rheumatoid arthritis. Despite this widespread use in the clinic, HCQ molecular modes of action are still not completely understood. By influencing several cellular pathways through different mechanisms, CQ and HCQ inhibit multiple endolysosomal functions, including autophagy, as well as endosomal Toll‐like receptor activation and calcium signalling. These effects alter several aspects of the immune system with the synergistic consequence of reducing pro‐inflammatory cytokine production and release, one of the most marked symptoms of RADs. Here, we review the current knowledge on the molecular modes of action of these drugs and the circumstances under which they trigger side effects. This is of particular importance as the therapeutic use of HCQ is expanding beyond the treatment of malaria and RADs.

Targeting the Immune System for Pulmonary Inflammation and Cardiovascular Complications in COVID-19 Patients

In December 2019, following a cluster of pneumonia cases in China caused by a novel coronavirus (CoV), named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the infection disseminated worldwide and, on March 11th, 2020, the World Health Organization officially declared the pandemic of the relevant disease named coronavirus disease 2019 (COVID-19). In Europe, Italy was the first country facing a true health policy emergency, and, as at 6.00 p.m. on May 2nd, 2020, there have been more than 209,300 confirmed cases of COVID-19. Due to the increasing number of patients experiencing a severe outcome, global scientific efforts are ongoing to find the most appropriate treatment. The usefulness of specific anti-rheumatic drugs came out as a promising treatment option together with antiviral drugs, anticoagulants, and symptomatic and respiratory support. For this reason, we feel a duty to share our experience and our knowledge on the use of these drugs in the immune-rheumatologic field, providing in this review the rationale for their use in the COVID-19 pandemic.