High-density lipoprotein inversely relates to its specific autoantibody favoring oxidation in thrombotic primary antiphospholipid syndrome

Humoral responses against HDL are linked to lipoprotein traits, atherosclerosis, inflammation and pathogenic pathways during early arthritis stages

OBJECTIVE

Chronic inflammation and immune dysregulation are crucial mechanisms for atherosclerosis in RA. Recent evidence suggests a link via humoral responses against high-density lipoproteins (HDL). This study aimed to characterize the specificity, clinical relevance and emergence of humoral responses against HDL along disease course, especially during the earliest phases of arthritis.

METHODS

IgG and IgM serum levels of antibodies against HDL (anti-HDL) and apolipoprotein A1 (anti-ApoA1) were measured in 82 early RA patients, 14 arthralgia individuals and 96 controls. Established RA patients (n = 42) were included for validation. Atherosclerosis and vascular stiffness were measured by Doppler ultrasound. Lipoprotein content, particle numbers and size were measured by H-NMR. Cytokines were measured by immunoassays. A cardiometabolic-related protein panel was evaluated using high-throughput targeted proteomics.

RESULTS

Anti-HDL and anti-ApoA1 responses were increased in early RA compared with controls (both P < 0.001) and were comparable to established disease. Only anti-ApoA1 antibodies were increased in arthralgia. IgG anti-HDL and anti-ApoA1 were associated with unfavourable lipoprotein traits in RA and arthralgia, respectively. A similar picture was observed for inflammatory mediators. No associations with clinical features or risk factors were found. IgG anti-HDL were independently associated with atherosclerosis occurrence in early RA, and outperformed patient stratification over conventional algorithms (mSCORE) and their anti-ApoA1 counterparts. Anti-HDL antibodies correlated with proteins involved in immune activation, remodelling and lipid metabolism pathways in early RA.

CONCLUSION

Humoral responses against HDL particles are an early event along the arthritis course, although quantitative and qualitative differences can be noticed among stages. These differences informed distinct capacities as biomarkers and underlying pathogenic circuits.

BMI-Associated Anti-Apolipoprotein A-1 Positivity in Healthy Adults after mRNA-Vaccination against COVID-19

Elevated anti-apolipoprotein A-1 (AAA1) antibody levels associated with cardiovascular risk have been observed in previously SARS-CoV-2-infected or COVID-19-vaccinated individuals. Since patient safety is generally a priority in vaccination, we sought to investigate AAA1 antibody levels in healthy adults after mRNA vaccination. We conducted a prospective cohort study in healthy adult volunteers recruited from military workers of the Transport Air Base in Prague who had received two doses of mRNA vaccines. Anti-apolipoprotein A-1 antibody levels were determined using ELISA from serum samples obtained at three and four time points after the first and second vaccine doses, respectively, within almost 17 weeks of follow-up. The transient AAA1 positivity rate achieved 24.1% (95% confidence interval CI: 15.4–34.7%), i.e., 20 out of 83 participants had at least one positive post-vaccination sample, with a repeat positivity confirmed in only 5 of them. This rate was associated with a BMI > 26 kg/m2, as documented by an adjusted odds ratio of 6.79 (95% CI: 1.53–30.01). In addition, the highest positivity rate of 46.7% (21.3–73.4%) was observed in obese subjects with >30 kg/m2. Since the incidence rate of AAA1 positivity remained unchanged after the first and second vaccine doses, any relationship between AAA1 positivity and mRNA vaccination was inconclusive. The present study showed a transient AAA1 positivity rate associated with overweight or obesity without a proven association with mRNA vaccination.

Artemisinin analogue SM934 protects against lupus-associated antiphospholipid syndrome via activation of Nrf2 and its targets

Kidney is a major target organ in both antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). The etiology of antiphospholipid syndrome nephropathy associated lupus nephritis (APSN-LN) is intricate and remains largely unrevealed. We proposed in present work, that generation of antiphospholipid antibodies (aPLs), especially those directed towards the oxidized neoepitopes, are largely linked with the redox status along with disease progression. Moreover, we observed that compromised antioxidative capacity coincided with turbulence of inflammatory cytokine profile in the kidney of male NZW×BXSB F1 mice suffered from APSN-LN. SM934 is an artemisinin derivative that has been proved to have potent immunosuppressive properties. In current study, we elaborated the therapeutic benefits of SM934 in male NZW×BXSB F1 mice, a murine model develops syndrome resembled human APS associated with SLE, for the first time. SM934 treatment comprehensively impeded autoantibodies production, inflammatory cytokine accumulation and excessive oxidative stress in kidney. Among others, we interpreted in present work that both anti-inflammatory and antioxidative effects of SM934 is closely correlated with the enhancement of Nrf2 signaling and expression of its targets. Collectively, our finding confirmed that therapeutic strategy simultaneously exerting antioxidant and anti-inflammatory efficacy provide a novel feasible remedy for treating APSN-LN.

Characterization of Antiphospholipid Syndrome Atherothrombotic Risk by Unsupervised Integrated Transcriptomic Analyses

OBJECTIVE

Our aim was to characterize distinctive clinical antiphospholipid syndrome phenotypes and identify novel microRNA (miRNA)-mRNA-intracellular signaling regulatory networks in monocytes linked to cardiovascular disease. Approach and Results: Microarray analysis in antiphospholipid syndrome monocytes revealed 547 differentially expressed genes, mainly involved in inflammatory, cardiovascular, and reproductive disorders. Besides, this approach identified several genes related to inflammatory, renal, and dermatologic diseases. Functional analyses further demonstrated phosphorylation of intracellular kinases related to thrombosis and immune-mediated chronic inflammation. miRNA profiling showed altered expression of 22 miRNAs, enriched in pathways related to immune functions, cardiovascular disease, and autoimmune-associated pathologies. Unbiased integrated mRNA-miRNA analysis identified a signature of 9 miRNAs as potential modulators of 17 interconnected genes related to cardiovascular disease. The altered expression of that miRNA-mRNA signature was proven to be stable along time and distinctive of nonautoimmune thrombotic patients. Transfection studies and luciferase assays established the relationship between specific miRNAs and their identified target genes and proteins, along with their involvement in the regulation of monocytes procoagulant activity and cell adhesion. Correlation analyses showed relationship among altered miRNAs and their interconnected genes with aPL (antiphospholipid antibodies)-titers, along with microvascular endothelial dysfunction. In vitro studies demonstrated modulation in healthy monocytes by IgG-aPLs of several genes/miRNAs, which further intermediated downstream effects on endothelial function. The identified transcriptomic signature allowed the unsupervised division of three clusters of patients with antiphospholipid syndrome showing distinctive clinical profiles, mainly associated with their prothrombotic risk (thrombosis, autoantibody profile, cardiovascular risk factors, and atherosclerosis).

CONCLUSIONS

Extensive molecular profiling of monocytes in patients with primary antiphospholipid syndrome might help to identify distinctive clinical phenotypes, thus enabling new patients' tailored treatments.

Antiphospholipid antibodies in end-stage renal disease: A systematic review and meta-analysis

INTRODUCTION

The relationship between autoimmune hemolytic anemia and antiphospholipid antibodies (aPL) and/or antiphospholipid syndrome has never been systematically addressed.

METHODS

Systematic review of EMBASE and PubMed databases performed according to PRISMA guidelines from inception to March 2020; meta-analysis performed by Peto's odds ratio for rare events.

FINDINGS

Forty-five studies with different outcomes met the inclusion/exclusion criteria. The pooled prevalence (PP) of IgG anticardiolipin antibodies (aCL) positivity was greater in end-stage renal disease (ESRD) than controls (20.2% vs. 2.6%, P = 0.001, I²  >80%; I² = heterogeneity), particularly in hemodialysis patients (18.3% vs. 8%, I² = 0%). The PP of lupus anticoagulant was greater in ESRD than controls (8.7% vs. 0.2%, P < 0.0001, I² = 0%). The standardized mean difference of IgG aCL favored ESRD rather than controls (P < 0.0001, I² =97%). The PP of fistula occlusion was greater in IgG aCL-positive patients than negative patients (39% vs. 27%, I² =97%); the PP of IgG aCL positivity was greater in patients with fistula occlusion than without fistula occlusion (26.9% vs. 23.2%, P = 0.01, I² =72%); the same applied to the PP of lupus anticoagulant positivity (23% vs. 0.3%, P < 0.0001, I² = 0%). The standardized mean difference of IgG aCL favored fistula occlusion (P = 0.004, I² = 91%).

DISCUSSION

Lupus anticoagulant relates to ESRD regardless of management whereas IgG aCL relates specifically to ESRD on hemodialysis, but only lupus anticoagulant associates with fistula occlusion. The expression of aPL as patients positive for aPL rather than as titers precludes further assumptions on the relationship.

Humoral Immunity Against HDL Particle: A New Perspective in Cardiovascular Diseases?

BACKGROUND

Autoimmune diseases are closely associated with cardiovascular diseases (CVD). Over the last decades, the comprehension of atherosclerosis, the principal initiator of CVD, evolved from a lipidcentered disease to a predominant inflammatory and immune response-driven disease displaying features of autoimmunity against a broad range of auto-antigens, including lipoproteins. Among them, high density lipoproteins (HDL) are important actors of cholesterol transport and bear several anti-atherogenic properties, raising a growing interest as therapeutic targets to decrease atherosclerosis and CVD burden, with nevertheless rather disappointing results so far. Reflecting HDL composition complexity, autoimmune responses and autoantibodies against various HDL components have been reported.

RESULTS

In this review, we addressed the important complexity of humoral autoimmunity towards HDL and particularly how this autoimmune response could help improving our understanding of HDL biological implication in atherosclerosis and CVD. We also discussed several issues related to specific HDL autoantibody subclasses characteristics, including etiology, prognosis and pathological mechanisms according to Rose criteria.

CONCLUSION

Finally, we addressed the possible clinical value of using these antibodies not only as potential biomarkers of atherogenesis and CVD, but also as a factor potentially mitigating the benefit of HDL-raising therapies.

Role of microRNAs in the Development of Cardiovascular Disease in Systemic Autoimmune Disorders

Rheumatoid Arthritis (RA), Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are the systemic autoimmune diseases (SADs) most associated with an increased risk of developing cardiovascular (CV) events. Cardiovascular disease (CVD) in SADs results from a complex interaction between traditional CV-risk factors, immune deregulation and disease activity. Oxidative stress, dyslipidemia, endothelial dysfunction, inflammatory/prothrombotic mediators (cytokines/chemokines, adipokines, proteases, adhesion-receptors, NETosis-derived-products, and intracellular-signaling molecules) have been implicated in these vascular pathologies. Genetic and genomic analyses further allowed the identification of signatures explaining the pro-atherothrombotic profiles in RA, SLE and APS. However, gene modulation has left significant gaps in our understanding of CV co-morbidities in SADs. MicroRNAs (miRNAs) are emerging as key post-transcriptional regulators of a suite of signaling pathways and pathophysiological effects. Abnormalities in high number of miRNA and their associated functions have been described in several SADs, suggesting their involvement in the development of atherosclerosis and thrombosis in the setting of RA, SLE and APS. This review focusses on recent insights into the potential role of miRNAs both, as clinical biomarkers of atherosclerosis and thrombosis in SADs, and as therapeutic targets in the regulation of the most influential processes that govern those disorders, highlighting the potential diagnostic and therapeutic properties of miRNAs in the management of CVD.

Antibodies towards high-density lipoprotein components in patients with psoriasis

Psoriasis is a chronic inflammatory immune disorder associated with an increased risk of atherosclerosis. This increased risk is not fully understood. High-density lipoproteins (HDL) play an important role in the prevention of atherosclerosis and any factors that may hamper HDL function such as anti-HDL antibodies (aHDL) might be associated with an increased cardiovascular risk. We aimed to determine whether anti-HDL antibodies (aHDL) are present in patients with psoriasis. Sixty-seven patients with psoriasis were compared with a healthy control group. Epidemiologic and clinical data were recorded. IgG and IgM aHDL, IgG anti-apolipoprotein A-I (aApoA-I), anti-apolipoprotein E (aApoE), and anti-paraoxonase 1 (aPON1) antibodies, as well as VCAM-1, IL-6, and TNF-α were assessed by ELISA. Apolipoprotein A-I (ApoA-I) and Apolipoprotein E (ApoE) were measured by immunoturbidimetric immunoassay. Patients with psoriasis had higher titers of IgG aHDL (p < 0.001), IgG aApoA-I (p = 0.001) and aApoE antibodies (p < 0.001). IgG aHDL and aApoE titers were higher in patients with severe psoriasis (p = 0.010 and p = 0.018, respectively). Multiple regression analysis, considering all clinical and biological variables, showed that aApoE, IL-6, and aPON1 are the biological variables that best explain aHDL variability. This is the first report showing the presence of aHDL, aApoA-I, and aApoE antibodies in patients with psoriasis. These antibodies were associated with increased disease severity and may contribute to the pathogenesis of atherosclerosis in psoriasis. They may fulfill the clinical need for biomarkers of cardiovascular risk associated with psoriasis that would help to stratify patients for prevention and therapeutic approaches.

IgG Anti-high-Density Lipoproteins Antibodies Discriminate Between Arterial and Venous Events in Thrombotic Antiphospholipid Syndrome Patients

Introduction: Recurrent thrombotic events are a hallmark of Antiphospholipid Syndrome (APS). However, biomarkers to identify if a patient with antiphospholipid antibodies (aPL) is at higher risk to develop an arterial or a venous event are lacking. Recently, the pathogenic role of anti-high-density lipoproteins antibodies (anti-HDL) in the occurrence of cardiovascular disease (CVD) in autoimmunity has emerged. The aim of the present study was to evaluate the presence of IgG anti-HDL antibodies in a cohort of thrombotic APS patients and to investigate their association with clinical outcomes. Methods: Serum levels of IgG anti-HDL antibodies, total IgG, and complete aPL profile were assessed in 60 APS patients and 80 healthy donors (HDs) by immunoassays. Results: Higher levels of IgG anti-HDL were found in APS patients compared to HDs (p < 0.001), even after correcting for total IgG levels (p < 0.001). No associations with treatments or traditional cardiovascular risk factors, except for smoking habit (p < 0.0001), were found. Patients who experienced at least one arterial event (n = 30) had significantly higher levels of anti-HDL antibodies when compared to patients with venous thrombosis (n = 30, p = 0.046), this difference being stronger when adjusting for total IgG (p = 0.007). Additionally, patients tested positive for antiphosphatidylserine/prothrombin (IgG/IgM) antibodies had significantly higher levels of anti-HDL antibodies (p = 0.045). Conclusions: Increased levels of IgG anti-HDL antibodies can be found in APS, mainly in patients with arterial thrombosis, independently of aPL antibodies and traditional risk factors. These findings point to a role of anti-HDL antibodies in APS and support their use as a potential biomarker for arterial thrombotic events.

Relationship between HDL Cholesterol Efflux Capacity, Calcium Coronary Artery Content, and Antibodies against ApolipoproteinA-1 in Obese and Healthy Subjects

AIMS

To explore the associations between cholesterol efflux capacity (CEC), coronary artery calcium (CAC) score, Framingham risk score (FRS), and antibodies against apolipoproteinA-1 (anti-apoA-1 IgG) in healthy and obese subjects (OS).

METHODS AND RESULTS

ABCA1-, ABCG1-, passive diffusion (PD)-CEC and anti-apoA-1 IgG were measured in sera from 34 controls and 35 OS who underwent CAC score determination by chest computed tomography. Anti-apoA-1 IgG ability to modulate CEC and macrophage cholesterol content (MCC) was tested in vitro. Controls and OS displayed similar ABCG1-, ABCA1-, PD-CEC, CAC and FRS scores. Logistic regression analyses indicated that FRS was the only significant predictor of CAC lesion. Overall, anti-apoA-1 IgG were significantly correlated with ABCA1-CEC (r = 0.48, p < 0.0001), PD-CEC (r = -0.33, p = 0.004), and the CAC score (r = 0.37, p = 0.03). ABCA1-CEC was correlated with CAC score (r = 0.47, p = 0.004) and FRS (r = 0.18, p = 0.29), while PD-CEC was inversely associated with the same parameters (CAC: r = -0.46, p = 0.006; FRS: score r = -0.40, p = 0.01). None of these associations was replicated in healthy controls or after excluding anti-apoA-1 IgG seropositive subjects. In vitro, anti-apoA-1 IgG inhibited PD-CEC (p < 0.0001), increased ABCA1-CEC (p < 0.0001), and increased MCC (p < 0.0001).

CONCLUSIONS

We report a paradoxical positive association between ABCA1-CEC and the CAC score, with the latter being inversely associated with PD in OS. Corroborating our clinical observations, anti-apoA-1 IgG enhanced ABCA1 while repressing PD-CEC, leading to MCC increase in vitro. These results indicate that anti-apoA-1 IgG have the potential to interfere with CEC and macrophage lipid metabolism, and may underpin paradoxical associations between ABCA1-CEC and cardiovascular risk.

ELISA methods comparison for the detection of auto-antibodies against apolipoprotein A1

BACKGROUND

Autoantibodies against apolipoprotein A1 (anti-apoA1 IgG) have emerged as an independent biomarker for cardiovascular disease and mortality. Across studies, different ELISA methods have been used to measure the level of circulating anti-apoA1 IgG which could lead to substantial result differences between assays.

OBJECTIVES

To make a comparative study of available anti-apoA1 IgG detection methods and to determine whether the choice of matrix sample (serum vs plasma) could influence the results.

METHODS

Blood samples were obtained from 160 healthy blood donors and collected on 4 different matrixes (serum, plasma-EDTA, -citrate, -lithium-heparinate). Anti-apoA1 IgG was measured using two homemade (Geneva's and Lisbon's) and one commercial ELISA kits. Passing-Bablok and Bland-Altman were used to compare the results. Anti-apoA1 IgG seropositivity cut-offs were defined according to the user's/manufacturer's criterion.

RESULTS

The current results showed substantial differences between those 3 assays. The dynamic ranges were significantly different, the commercial kit displaying the narrowest one. Passing-Bablok analysis demonstrated important proportional and constant biases between assays. The anti-apoA1 IgG seropositivity rate in Geneva, Lisbon and commercial assays varied between 24.5% and 1.9%. Matrix comparisons demonstrated that the matrix choice (plasma versus serum) influenced anti-apoA1 IgG results as well as the seropositivity rate in an assay-dependent manner. The coating antigen source was identified as important factor underlying results heterogeneity across assays.

CONCLUSIONS

These results highlight the impact of the method and the cut-off used on anti-apoA1 IgG results and emphasize the need of standardizing existing assays. Given the important matrix influence, we suggest to use serum as matrix of choice.

Antibodies Against the C-Terminus of ApoA-1 Are Inversely Associated with Cholesterol Efflux Capacity and HDL Metabolism in Subjects with and without Type 2 Diabetes Mellitus

Background: We determined relationships of cholesterol efflux capacity (CEC), plasma cholesterol esterification (EST) and cholesteryl ester transfer (CET) with anti-c-terminus apoA-1 (Ac-terAA1) and anti-apolipoprotein (apo)-1 (AAA1) autoantibodies in subjects with and without Type 2 diabetes mellitus (T2D). Methods: In 75 T2D subjects and 75 nondiabetic subjects, Ac-terAA1 and AAA1 plasma levels were measured by enzyme-linked immunosorbent assay. CEC was measured as [³H]-cholesterol efflux from human cultured fibroblasts to diluted individual subject plasma. Plasma EST and CET were assayed by isotope methods. Results: Ac-terAA1 and AAA1 levels and were similar between T2D and control subjects. Univariate regression analysis (n = 150) demonstrated that Ac-terAA1 levels were inversely correlated with CEC, EST, CET, total cholesterol, non-HDL cholesterol, triglycerides and apolipoprotein B, (p < 0.05 to p < 0.01), but not with glucose and HbA1c. In separate multivariable linear regression models, CEC, EST and CET were inversely associated with Ac-terAA1 levels independently of age, sex, T2D and drug use (β = −0.186, p = 0.026; β = −0.261, p < 0.001; and β = −0.321, p < 0.001; respectively). These associations were lost after additional adjustment for non-HDL cholesterol and triglycerides. No associations were observed for AAA1. Conclusions: CEC, plasma EST and CET are inversely associated with Ac-terAA1 autoantibodies, conceivably attributable to an inverse relationship of these autoantibodies with apolipoprotein B-containing lipoproteins.

Impact of CD14 Polymorphisms on Anti-Apolipoprotein A-1 IgG-Related Coronary Artery Disease Prediction in the General Population

Objective—

We aimed to determine whether autoantibodies against apoA-1 (apolipoprotein A-1; anti-apoA-1 IgG) predict incident coronary artery disease (CAD), defined as adjudicated incident myocardial infarction, angina, percutaneous coronary revascularization, or bypass grafting, in the general population. We further investigated whether this association is modulated by a functional CD14 receptor single nucleotide polymorphism.

Approach and Results—

In a prospectively studied, population-based cohort of 5220 subjects (mean age 52.6±10.7 years, 47.4% males), followed over a median period of 5.6 years, subjects positive versus negative for anti-apoA-1 IgG presented a total CAD rate of 3.9% versus 2.8% ( P =0.077) and a nonfatal CAD rate of 3.6% versus 2.3% ( P =0.018), respectively. After multivariate adjustment for established cardiovascular risk factors, the hazard ratios of anti-apoA-1 IgG for total and nonfatal CAD were: hazard ratio=1.36 (95% confidence interval, 0.94–1.97; P =0.105) and hazard ratio=1.53 (95% confidence interval, 1.03–2.26; P =0.034), respectively. In subjects with available genetic data for the C260T rs2569190 single nucleotide polymorphism in the CD14 receptor gene (n=4247), we observed a significant interaction between anti-apoA-1 IgG and rs2569190 allele status with regards to CAD risk, with anti-apoA-1 IgG conferring the highest risk for total and nonfatal CAD in non-TT carriers, whereas being associated with the lowest risk for total and nonfatal CAD in TT homozygotes ( P for interaction =0.011 and P for interaction =0.033, respectively).

Conclusions—

Anti-apoA-1 IgG are independent predictors of nonfatal incident CAD in the general population. The strength of this association is dependent on a functional polymorphism of the CD14 receptor gene, a finding suggesting a gene–autoantibody interaction for the development of CAD.

Anti-apoA-1 auto-antibodies increase mouse atherosclerotic plaque vulnerability, myocardial necrosis and mortality triggering TLR2 and TLR4

Auto-antibodies to apolipoprotein A-1 (anti-apoA-1 IgG) were shown to promote inflammation and atherogenesis, possibly through innate immune receptors signalling. Here, we aimed at investigating the role of Toll-like receptors (TLR) 2 and 4 on anti-apoA-1 IgG-induced athero-sclerotic plaque vulnerability, myocardial necrosis and mortality in mice. Adult male apolipoprotein E knockout (ApoE)-/- (n=72), TLR2-/-ApoE-/- (n=36) and TLR4-/-Apo-/- (n=28) mice were intravenously injected with 50 µg/mouse of endotoxin-free polyclonal anti-apoA-1 IgG or control isotype IgG (CTL IgG) every two weeks for 16 weeks. Atherosclerotic plaque size and vulnerability were assessed by histology. Myocardial ischaemia and necrosis, respectively, were determined by electrocardiographic (ECG) changes assessed by telemetry and serum troponin I (cTnI) measurements. Impact on survival was assessed by Kaplan-Meier analyses. In ApoE-/- mice, anti-apoA-1 IgG passive immunisation enhanced histological features of athero-sclerotic plaque vulnerability (increase in neutrophil and MMP-9 and reduction in collagen content), induced a substantial cTnI elevation (p=0.001), and increased mortality rate by 23 % (LogRank, p=0.04) when compared to CTL IgG. On a subgroup of ApoE-/- mice equipped with telemetry (n=4), a significant ST-segment depression was noted in anti-apoA-1 IgG-treated mice when compared to CTL IgG recipients (p< 0.001), and an acute ST-segment elevation myocardial infarction preceding mouse death was observed in one case. The deleterious effects of anti-apoA-1 IgG on atherosclerotic plaque vulnerability, myocardial necrosis and death were partially reversed in TLR2-/-ApoE-/- and TLR4-/-ApoE-/- backgrounds. In conclusion, anti-apoA-1 auto-antibodies seem to be active mediators of atherosclerotic plaque vulnerability, myocardial necrosis, and mortality in mice through TLR2- and TLR4-mediated pathways.

Ubiquinol Effects on Antiphospholipid Syndrome Prothrombotic Profile: A Randomized, Placebo-Controlled Trial

OBJECTIVE

Antiphospholipid syndrome (APS) leukocytes exhibit an oxidative perturbation, directly linked to alterations in mitochondrial dynamics and metabolism. This disturbance is related to the patients' prothrombotic status and can be prevented by in vitro treatment with coenzyme Q10. Our aim was to investigate short-term effects of in vivo ubiquinol (reduced coenzyme Q₁₀ [Q_red]) supplementation on markers related to inflammation and thrombosis in APS through a prospective, randomized, crossover, placebo-controlled trial.

APPROACH AND RESULTS

Thirty-six patients with APS were randomized to receive Q_red (200 mg/d) or placebo for 1 month. Thirty-three patients with APS completed the intervention, which increased plasma coenzyme Q₁₀. Q_red improved endothelial function and decreased monocyte expression of prothrombotic and proinflammatory mediators, inhibited phosphorylation of thrombosis-related protein kinases, and decreased peroxides and percentage of monocytes with depolarized mitochondria; mitochondrial size was increased, and mitochondrial biogenesis-related genes were upregulated. Q_red ameliorated extruded neutrophil extracellular traps in neutrophils and downregulated peroxides, intracellular elastase, and myeloperoxidase. Nanostring microRNA profiling revealed 20 microRNAs reduced in APS monocytes, and 16 of them, with a preponderance of cardiovascular disease-related target mRNAs, were upregulated. Monocytes gene profiling showed differential expression of 29 atherosclerosis-related genes, 23 of them changed by Q_red. Interaction networks of genes and microRNAs were identified. Correlation studies demonstrated co-ordinated effects of Q_red on thrombosis and endothelial function-associated molecules.

CONCLUSIONS

Our results highlight the potential of Q_red to modulate the overexpression of inflammatory and thrombotic risk markers in APS. Because of the absence of clinically significant side effects and its potential therapeutic benefits, Q_red might act as safe adjunct to standard therapies in APS.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02218476.

Anti-Apolipoprotein A-1 IgG Predict All-Cause Mortality and Are Associated with Fc Receptor-Like 3 Polymorphisms

Background

Autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG) have emerged as an independent biomarker for cardiovascular disease and mortality. However, their association with all-cause mortality in the community, as well as their genetic determinants, have not been studied.

Objective

To determine whether anti-apoA-1 IgG: (a) predict all-cause mortality in the general population and (b) are associated with single-nucleotide polymorphisms (SNPs) in a genome-wide association study (GWAS).

Methods

Clinical, biological, and genetic data were obtained from the population-based, prospective CoLaus study, including 5,220 participants (mean age 52.6 years, 47.3% men) followed over a median duration of 5.6 years. The primary study outcome was all-cause mortality.

Results

After multivariate adjustment, anti-apoA-1 IgG positivity independently predicted all-cause mortality: hazard ratio (HR) = 1.54, 95% confidence interval (95% CI): 1.11–2.13, P = 0.01. A dose–effect relationship was also observed, each SD of logarithmically transformed anti-apoA-1 IgG being associated with a 15% increase in mortality risk: HR = 1.15, 95% CI: 1.02–1.28, P = 0.028. The GWAS yielded nine SNPs belonging to the Fc receptor-like 3 (FCRL3) gene, which were significantly associated with anti-apoA-1 IgG levels, with the lead SNP (rs6427397, P = 1.54 × 10⁻⁹) explaining 0.67% of anti-apoA-1 IgG level variation.

Conclusion

Anti-apoA-1 IgG levels (a) independently predict all-cause mortality in the general population and (b) are linked to FCRL3, a susceptibility gene for numerous autoimmune diseases. Our findings indicate that preclinical autoimmunity to anti-apoA-1 IgG may represent a novel mortality risk factor.

Extended-release niacin increases anti-apolipoprotein A-I antibodies that block the antioxidant effect of high-density lipoprotein-cholesterol: the EXPLORE clinical trial

AIMS

Extended-release niacin (ERN) is the most effective agent for increasing high-density lipoprotein-cholesterol (HDL-C). Having previously identified anti-HDL antibodies, we investigated whether ERN affected the antioxidant capacity of HDL and whether ERN was associated with the production of antibodies against HDL (aHDL) and apolipoprotein A-I (aApoA-I).

METHODS

Twenty-one patients older than 18 years, with HDL-C ≤40 mg dl^-1 (men) or ≤50 mg dl^-1 (women) were randomly assigned to receive daily ERN (n = 10) or placebo (n = 11) for two sequential 12-week periods, with 4 weeks of wash-out before cross-over. Primary outcome was change of paraoxonase-1 (PON1) activity and secondary outcomes were changes in aHDL and aApoA-I antibodies. Clinical Trial Unique Identifier: EudraCT 2006-006889-42.

RESULTS

The effect of ERN on PON1 activity was nonsignificant (coefficient estimate 20.83 U l^-1 , 95% confidence interval [CI] -9.88 to 51.53; P = 0.184). ERN was associated with an increase in HDL-C levels (coefficient estimate 5.21 mg dl^-1 , 95% CI 1.16 to 9.25; P = 0.012) and its subclasses HDL2 (coefficient estimate 2.46 mg dl^-1 , 95% CI 0.57 to 4.34; P = 0.011) and HDL3 (coefficient estimate 2.73 mg dl^-1 , 95% CI 0.47 to 4.98; P = 0.018). ERN was significantly associated with the production of aApoA-I antibodies (coefficient estimate 0.25 μg ml^-1 , 95% CI 0.09-0.40; P = 0.001). aApoA-I titres at baseline were correlated with decreased PON activity.

CONCLUSIONS

The rise in HDL-C achieved with ERN was not matched by improved antioxidant capacity, eventually hampered by the emergence of aApoA-I antibodies. These results may explain why Niacin and other lipid lowering agents fail to reduce cardiovascular risk.

Proinflammatory proteins in female and male patients with primary antiphospholipid syndrome: preliminary data

The latest classification criteria for the diagnosis of the antiphospholipid syndrome (APS, an autoimmune disease characterized by thromboses, miscarriages and presence of antiphospholipid antibodies (Abs)) emphasized that thrombotic manifestations of APS should be without any signs of an inflammatory process. However, atherosclerosis (a chronic inflammatory response to the accumulation of lipoproteins in the walls of arteries) and APS are characterized by some similar features. We evaluated whether proinflammatory proteins were associated with the features of the primary APS (PAPS). PAPS patients without obstetric complications and with impaired lipid profile were included in the study. Antiphospholipid antibodies, TNF-alpha, and apo(a) were determined by ELISA. Complement components and hsCRP were measured by immunonephelometry. Decreased C3c was observed in female patients with increased titers of IgG anti-β2gpI (χ(2) = 3.939, P = 0.047) and in male patients with increased IgM anticardiolipin Abs (χ(2) = 4.286, P = 0.038). Pulmonary emboli were associated with interleukin (IL)-6 in male (χ(2) = 6.519, P = 0.011) and in female (χ(2) = 10.405, P = 0.001) patients. Cerebrovascular insults were associated with LDL-cholesterol (P = 0.05, 95 % CI: 1.003 - 12.739) in female and with apo(a) (P = 0.016, 95 % CI: 0.000-0.003) in male patients. Older female patients had increased LDL-cholesterol levels and frequency of myocardial infarctions. Proinflammatory proteins were associated with features of primary APS. No real gender differences in regard to proinflammatory protein levels were observed. Premenopausal state of female PAPS patients confers lower cardiovascular risk.

ApoA1 and ApoA1-specific self-antibodies in cardiovascular disease

Apolipoprotein A1 (ApoA1) is a main protein moiety in high-density lipoprotein (HDL) particles. Generally, ApoA1 and HDL are considered as atheroprotective. In prooxidant and inflammatory microenvironment in the vicinity to the atherosclerotic lesion, ApoA1/HDL are subjected to modification. The chemical modifications such as oxidation, nitration, etc result in altering native architecture of ApoA1 toward dysfunctionality and abnormality. Neutrophil myeloperoxidase has a prominent role in this mechanism. Neo-epitopes could be formed and then exposed that makes them immunogenic. Indeed, these epitopes may be recognized by immune cells and induce production of proatherogenic ApoA1-specific IgG antibodies. These antibodies are biologically relevant because they are able to react with Toll-like receptor (TLR)-2 and TLR4 in target cells and induce a variety of pro-inflammatory responses. Epidemiological and functional studies underline a prognostic value of ApoA1 self-antibodies for several cardiovascular diseases, including myocardial infarction, acute coronary syndrome, and severe carotid stenosis.

Anti-apolipoprotein A-1 auto-antibodies as active modulators of atherothrombosis

Humoral autoimmune-mediated inflammation plays a role in atherogenesis, and potentially in arterial thrombosis. Anti-apolipoprotein A-1 (apoA-1) IgG have been reported to represent emergent mediators of atherogenesis through Toll-like receptors (TLR) 2, 4 and CD14 signalling. We investigated the role of anti-apoA-1 IgG on tissue factor (TF) expression and activation, a key coagulation regulator underlying atherothrombosis. Atherothrombosis features were determined by immunohistochemical TF staining of human carotid biopsies derived from patients with severe carotid stenosis undergoing elective surgery (n=176), and on aortic roots of different genetic backgrounds mice (ApoE-/-; TLR2-/-ApoE-/- and TLR4-/-ApoE-/-) exposed to passive immunisation with anti-apoA-1 IgG. Human serum levels of anti-apoA-1 IgG were measured by ELISA. In vitro, on human-monocyte-derived-macrophages (HMDM) the anti-apoA-1 IgG increased TF expression and activity were analysed by FACS and chromogenic assays in presence of different pharmacological inhibitors. Human serum anti-apoA-1 IgG levels significantly correlated to intraplaque TF expression in carotid biopsies (r=0.31, p<0.001), which was predictive of clinically symptomatic lesions. On HMDM, anti-apoA-1 IgG induced a TLR2, 4 and CD14-dependent increase in TF expression and activity, involving NF-kappaB and a c-Jun N-terminal kinase-dependent AP-1 transcription factors. In ApoE-/- mice, anti-apoA-1 IgG passive immunisation significantly enhanced intraplaque TF expression when compared to control IgG. This effect was lost in both TLR2-/-ApoE-/- and TLR4-/-ApoE-/- mice. These results demonstrate that anti-apoA-1 IgG are associated with TF expression in human atherosclerotic plaques, induce TF expression in vitro and in vivo through TLR2 and 4 signalling, supporting a possible causal relationship between anti-apoA-1 IgG and atherothrombosis.

Oxidative stress in the pathogenesis of atherothrombosis associated with anti-phospholipid syndrome and systemic lupus erythematosus: new therapeutic approaches

Atherothrombosis is a recurrent complication in APS and SLE patients. Oxidative stress has been suggested as a key player underlying this process. Autoantibodies have been pointed to as the main contributors to abnormality in the oxidative status observed in APS and SLE patients, promoting the increased production of oxidant species and the reduction of antioxidant molecules. This imbalance causes vascular damage through the activation of immune cells, including monocytes, lymphocytes and neutrophils, causing the expression of pro-inflammatory and procoagulant molecules, the formation of neutrophil extracellular traps and the adhesion of these cells to the endothelium; the induction of cellular apoptosis and impaired cell clearance, which in turn enhances autoantibody neogeneration; and cytotoxicity of endothelial cells. This review describes the mechanisms underlying the role of oxidative stress in the pathogenesis of atherothrombosis associated with APS and SLE, focused on the effect of autoantibodies, the different cell types involved and the diverse effectors, including cytokines, procoagulant proteins and their main modulators, such as oxidant/antioxidant species and intracellular pathways in each pathology. We further discuss new therapies aimed at restoring the oxidative stress balance and subsequently to tackle atherothrombosis in APS and SLE.

Differences in Liver Injury and Trophoblastic Mitochondrial Damage in Different Preeclampsia-like Mouse Models

Background:

Preeclampsia is a multifactorial disease during pregnancy. Dysregulated lipid metabolism may be related to some preeclampsia. We investigated the relationship between triglycerides (TGs) and liver injury in different preeclampsia-like mouse models and their potential common pathways.

Methods:

Preeclampsia-like models (Nw-nitro-L-arginine-methyl ester [L-NAME], lipopolysaccharide [LPS], apolipoprotein C-III [Apo] transgnic mice + L-NAME, β2 glycoprotein I [βGPI]) were used in four experimental groups: L-NAME (LN), LPS, Apo-LN and βGPI, respectively, and controls received saline (LN-C, LPS-C, Apo-C, βGPI-C). The first three models were established in preimplantation (PI), early-, mid- and late-gestation (EG, MG and LG). βGPI and controls were injected before implantation. Mean arterial pressure (MAP), 24-hour urine protein, placental and fetal weight, serum TGs, total cholesterol (TC) and pathologic liver and trophocyte changes were assessed.

Results:

MAP and proteinuria were significantly increased in the experimental groups. Placenta and fetal weight in PI, EP and MP subgroups were significantly lower than LP. Serum TGs significantly increased in most groups but controls. TC was not different between experimental and control groups. Spotty hepatic cell necrosis was observed in PI, EG, MG in LN, Apo-LN and βGPI, but no morphologic changes were observed in the LPS group. Similar trophoblastic mitochondrial damage was observed in every experimental group.

Conclusions:

Earlier preeclampsia onset causes a higher MAP and urine protein level, and more severe placental and fetal damage. Preeclampsia-like models generated by varied means lead to different changes in lipid metabolism and associated with liver injury. Trophoblastic mitochondrial damage may be the common terminal pathway in different preeclampsia-like models.

Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

SIGNIFICANCE

Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells.

RECENT ADVANCES

Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results.

CRITICAL ISSUES

NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke.

FUTURE DIRECTIONS

Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke.

The Human Autoantibody Response to Apolipoprotein A-I Is Focused on the C-Terminal Helix: A New Rationale for Diagnosis and Treatment of Cardiovascular Disease?

Background

Cardiovascular disease (CVD) is the leading cause of death worldwide and new approaches for both diagnosis and treatment are required. Autoantibodies directed against apolipoprotein A-I (ApoA-I) represent promising biomarkers for use in risk stratification of CVD and may also play a direct role in pathogenesis.

Methodology

To characterize the anti-ApoA-I autoantibody response, we measured the immunoreactivity to engineered peptides corresponding to the different alpha-helical regions of ApoA-I, using plasma from acute chest pain cohort patients known to be positive for anti-ApoA-I autoantibodies.

Principal Findings

Our results indicate that the anti-ApoA-I autoantibody response is strongly biased towards the C-terminal alpha-helix of the protein, with an optimized mimetic peptide corresponding to this part of the protein recapitulating the diagnostic accuracy for an acute ischemic coronary etiology (non-ST segment elevation myocardial infarction and unstable angina) obtainable using intact endogenous ApoA-I in immunoassay. Furthermore, the optimized mimetic peptide strongly inhibits the pathology-associated capacity of anti-ApoA-I antibodies to elicit proinflammatory cytokine release from cultured human macrophages.

Conclusions

In addition to providing a rationale for the development of new approaches for the diagnosis and therapy of CVD, our observations may contribute to the elucidation of how anti-ApoA-I autoantibodies are elicited in individuals without autoimmune disease.

Definition of human apolipoprotein A-I epitopes recognized by autoantibodies present in patients with cardiovascular diseases

Autoantibodies to apolipoprotein A-I (anti-apoA-I IgG) have been shown to be both markers and mediators of cardiovascular disease, promoting atherogenesis and unstable atherosclerotic plaque. Previous studies have shown that high levels of anti-apoA-I IgGs are independently associated with major adverse cardiovascular events in patients with myocardial infarction. Autoantibody responses to apoA-I can be polyclonal and it is likely that more than one epitope may exist. To identify the specific immunoreactive peptides in apoA-I, we have developed a set of methodologies and procedures to isolate, purify, and identify novel apoA-I endogenous epitopes. First, we generated high purity apoA-I from human plasma, using thiophilic interaction chromatography followed by enzymatic digestion specifically at lysine or arginine residues. Immunoreactivity to the different peptides generated was tested by ELISA using serum obtained from patients with acute myocardial infarction and high titers of autoantibodies to native apoA-I. The immunoreactive peptides were further sequenced by mass spectrometry. Our approach successfully identified two novel immunoreactive peptides, recognized by autoantibodies from patients suffering from myocardial infarction, who contain a high titer of anti-apoA-I IgG. The discovery of these epitopes may open innovative prognostic and therapeutic opportunities potentially suitable to improve current cardiovascular risk stratification.

Autoantibodies to apolipoprotein A-1 as a biomarker of cardiovascular autoimmunity

Immune-driven inflammation plays an important part in atherogenesis and is therefore believed to be key to the development of cardiovascular disease (CVD), which is currently the leading cause of death in the Western world. By fulfilling some of the Koch postulates, atherogenesis has even been proposed to be considered as an autoimmune disease, raising the hope that CVD could be prevented by immunomodulation. Nevertheless, the role of the immune system and autoimmune reactions in atherosclerosis appear to be a double edged-sword, with both pro-atherogenic and anti-atherogenic attributes. Hence, if immunomodulation is to become a therapeutic option for atherosclerosis and CVD, it will be crucial to correctly identify patients who might benefit from targeted suppression of deleterious autoimmune responses. This could be achieved, for example, by the detection of disease-associated autoantibodies. In this work, we will review the currently available clinical, in vitro, and animal studies dedicated to autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG), the major proteic fraction of high density lipoprotein. Current clinical studies indicate that high levels of anti-apoA-1 IgG are associated with a worse cardiovascular prognosis. In addition, in vitro and animal studies indicate a pro-inflammatory and pro-atherogenic role, supporting the hypothesis that these autoantibodies may play a direct causal role in CVD, and furthermore that they could potentially represent a therapeutic target for CVD in the future.

Gene profiling reveals specific molecular pathways in the pathogenesis of atherosclerosis and cardiovascular disease in antiphospholipid syndrome, systemic lupus erythematosus and antiphospholipid syndrome with lupus

Objective

To identify shared and differential molecular pathways involved in the pathogenesis of atherosclerosis (AT) and cardiovascular disease (CVD) in systemic lupus erythematosus (SLE), primary antiphospholipid syndrome (APS) and APS associated with SLE (APS plus SLE).

Methods

129 patients (42 APS, 31 APS plus SLE and 56 SLE) and 61 healthy donors were included. Microarray expression profiling was performed in monocytes. RT-PCR of selected genes and western blot were used to validate microarray data. Clinical and inflammatory parameters were also analysed.

Results

Compared with controls, 555, 1224 and 518 genes were differentially expressed in monocytes from SLE, APS plus SLE and APS patients, respectively. Approximately 25–30% of differentially expressed genes were related to AT and CVD. Each disease displayed a specific AT/CVD/Inflammation-related gene signature. Compared with SLE, APS showed alterations in mitochondria biogenesis and function and oxidative stress. Besides the interferon signature, found in APS plus SLE and SLE patients, various genes mediating atherosclerotic/inflammatory signalling were also differentially expressed in APS plus SLE. IgG-anticardiolipin (aCL) titres independently predicted both atherosclerotic and thrombosis in APS plus SLE. Moreover, a significant correlation of IgG-aCL titres with mRNA levels of certain inflammatory molecules in monocytes was further noticed. In vitro treatment of monocytes with IgG-aCL promoted an increase in the expression of the genes most significantly changed in APS plus SLE versus healthy donors.

Conclusions

Gene expression profiling allows the segregation of APS, APS plus SLE and SLE, with specific signatures explaining the pro-atherosclerotic and pro-thrombotic alterations in these highly related autoimmune diseases.

14th International Congress on Antiphospholipid Antibodies: task force report on antiphospholipid syndrome treatment trends

Antiphospholipid Syndrome (APS) is characterized by vascular thrombosis and/or pregnancy morbidity occurring in patients with persistent antiphospholipid antibodies (aPL). The primary objective of the APS Treatment Trends Task Force, created as part of the 14th International Congress on aPL, was to systematically review the potential future treatment strategies for aPL-positive patients. The task force chose as future clinical research directions: a) determining the necessity for controlled clinical trials in venous thromboembolism with the new oral direct thrombin or anti-factor Xa inhibitors pending the results of the ongoing rivaroxaban in APS (RAPS) trial, and designing controlled clinical trials in other forms of thrombotic APS; b) systematically analyzing the literature as well as aPL/APS registries, and creating specific registries for non-warfarin/heparin anticoagulants; c) increasing recruitment for an ongoing primary thrombosis prevention trial, and designing secondary thrombosis and pregnancy morbidity prevention trials with hydroxychloroquine; d) determining surrogate markers to select patients for statin trials; e) designing controlled studies with rituximab and other anti-B-cell agents; f) designing mechanistic and clinical studies with eculizumab and other complement inhibitors; and g) chemically modifying peptide therapy to improve the half-life and minimize immunogenicity. The report also includes recommendations for clinicians who consider using these agents in difficult-to-manage aPL-positive patients.

Auto-antibodies as emergent prognostic markers and possible mediators of ischemic cardiovascular diseases

During the last 15 years, a growing body of evidence supported the fact that auto-antibodies represent not only emergent markers but also active mediators of cardiovascular disease (CVD), clinically represented mostly by acute coronary syndrome (ACS) and stroke. There is a contrasted relationship between auto-antibodies and CVD, some being protective, while others acting as potential risk factors. Therefore, we performed a review of the literature on the respective cardiovascular prognostic value of the most relevant auto-antibodies in ACS and stroke, and their putative pathophysiological properties in atherogenesis. This review highlights auto-antibodies as active modulators of the innate immune system in atherogenesis (either toward a pro- or anti-inflammatory response), or by affecting basal heart rate regulation (anti-apoA-1 IgG). Given their apparent prognostic independency towards traditional cardiovascular risk factors, the data available in the literature indicates that some of those auto-antibodies could be of valuable help for cardiovascular risk stratification in the future, especially because their deleterious effects have been shown to be potentially abrogated in vivo and in vitro by existing therapeutic modalities. Although evidence in humans is currently lacking, these studies may open innovative therapeutic perspectives for CVD in the future.

Evidence on the pathogenic role of auto-antibodies in acute cardiovascular diseases

Atherothrombosis is the major determinant of acute ischaemic cardiovascular events, such as myocardial infarction and stroke. Inflammatory processes have been linked to all phases of atherogenesis In particular, the identification of autoimmunity mediators in the complex microenvironment of chronic inflammation has become the focus of attention in both early and advanced atherogenic processes. Auto-antibodies against self-molecules or new epitopes generated by oxidative processes infiltrate atherosclerotic plaques and were shown to modulate the activity of immune cells by binding various types of receptors. However, despite mounting evidence for a pathophysiological role of autoantibodies in atherothrombosis, the clinical relevance for circulating autoantibodies in cardiovascular outcomes is still debated. This review aims at illustrating the mechanisms by which different types of autoantibodies might either promote or repress atherothrombosis and to discuss the clinical studies assessing the role of auto-antibodies as prognostic biomarkers of plaque vulnerability.

Serum levels of anti-apolipoprotein A-1 auto-antibodies and myeloperoxidase as predictors of major adverse cardiovascular events after carotid endarterectomy

We aimed at challenging the prognostic accuracies of myeloperoxidase (MPO) and antibodies anti-apolipoprotein A-1 (anti-apoA-1 IgG), alone or in combination, for major adverse cardiovascular events (MACE) prediction, one year after carotid endarterectomy (CEA). In this prospective single centre study, 178 patients undergoing elective CEA were included. Serum anti-apoA-1 IgG and MPO were assessed by enzyme-linked immunosorbent assay prior to the surgery. Post-hoc determination of the MPO cut-off was performed by receiver operating characteristics (ROC) analyses. MACE was defined by the occurrence of fatal or non-fatal acute coronary syndromes or stroke during one year follow-up. Prognostic accuracy of anti-apoA-1 IgG was assessed by ROC curve analyses, survival analyses and reclassification statistics. During follow-up, 5% (9/178) of patients presented a MACE, and 29% (52/178) were positive for anti-apoA-1 IgG. Patients with MACE had higher median MPO and anti-apoA-1 IgG levels at admission (p=0.01), but no difference for the 10-year global Framingham risk score (FRS) was observed (p=0.22). ROC analyses indicated that both MPO and anti-apoA-1 IgG were significant predictors of subsequent MACE (area under the curve [AUC]: 0.75, 95% confidence interval [95%CI]: 0.61-0.89, p=0.01; and 0.74, 95%CI: 0.59-90; p=0.01), but combining anti-apoA-1 IgG positivity and MPO>857 ng/ml displayed the best predictive accuracy (AUC: 0.78, 95%CI: 0.65-0.91; p=0.007). It was associated with a poorer MACE-free survival (98.2% vs. 57.1%; p<0.001, LogRank), with a positive likelihood ratio of 13.67, and provided incremental predictive ability over FRS. In conclusion, combining the assessment of anti-apoA-1 IgG and MPO appears as a promising risk stratification tool in patients with severe carotid stenosis.

Autoantibodies to apolipoprotein A-1 in cardiovascular diseases: current perspectives

Immune-mediated inflammation plays a major role in atherosclerosis and atherothrombosis, two essential features for cardiovascular disease (CVD) development, currently considered as the leading cause of death in the western world. There is accumulating evidence showing that humoral autoimmunity might play an important role in CVD and that some autoantibodies could represent emerging cardiovascular risk factors. Recent studies demonstrate that IgG autoantibodies against apolipoprotein A-1 (apoA-1) are raised in many diseases associated with a high cardiovascular risk, such as systemic lupus erythematosus, acute coronary syndrome, rheumatoid arthritis, severe carotid stenosis, and end-stage renal disease. In this work, we aimed at reviewing current data in the literature pointing to anti-apolipoprotein A-1 antibodies (anti-apoA-1 IgG) as a possible prognostic and diagnostic biomarker of cardiovascular risk and appraising their potential role as active mediators of atherogenesis.

Anti-apolipoprotein A-1 IgG levels predict coronary artery calcification in obese but otherwise healthy individuals

We aimed at determining whether anti-apolipoprotein (apo) A-1 IgG levels are independent predictors of coronary artery calcification (CAC) and coronary endothelial dysfunction in obese and nonobese subjects without cardiovascular disease. 48 nonobese and 43 obese subjects were included. CAC score was measured by thorax scanner and defined by an Agatston score > 0. Coronary endothelial dysfunction was determined by measuring myocardial blood flow responses to cold pressor test (CPT) on PET/CT. Serum anti-apoA-1 IgG levels were measured by ELISA. Prevalence of coronary calcification was similar between the two study groups, but the prevalence of coronary endothelial dysfunction was higher in obese subjects. Anti-apoA-1 IgG levels and positivity rate were higher in obese than in nonobese individuals. CAC score was higher in anti-apoA-1 IgG positive subjects. ROC analyses indicated that anti-apoA-1 IgG levels were significant predictors of CAC > 0, but not of coronary endothelial dysfunction with a negative predictive value of 94%. Anti-apoA-1 IgG positivity was associated with a 17-fold independent increased risk of CAC > 0. In conclusion, those preliminary results indicate that anti-apoA-1 IgG autoantibodies are raised in obese subjects and independently predict the presence of coronary calcification in this population but not the presence of coronary endothelial dysfunction.

Mitochondrial dysfunction in antiphospholipid syndrome: implications in the pathogenesis of the disease and effects of coenzyme Q(10) treatment

The exact mechanisms underlying the role of oxidative stress in the pathogenesis and the prothrombotic or proinflammatory status of antiphospholipid syndrome (APS) remain unknown. Here, we investigate the role of oxidative stress and mitochondrial dysfunction in the proatherothrombotic status of APS patients induced by IgG-antiphospholipid antibodies and the beneficial effects of supplementing cells with coenzyme Q(10) (CoQ(10)). A significant increase in relevant prothrombotic and inflammatory parameters in 43 APS patients was found compared with 38 healthy donors. Increased peroxide production, nuclear abundance of Nrf2, antioxidant enzymatic activity, decreased intracellular glutathione, and altered mitochondrial membrane potential were found in monocytes and neutrophils from APS patients. Accelerated atherosclerosis in APS patients was found associated with their inflammatory or oxidative status. CoQ(10) preincubation of healthy monocytes before IgG-antiphospholipid antibody treatment decreased oxidative stress, the percentage of cells with altered mitochondrial membrane potential, and the induced expression of tissue factor, VEGF, and Flt1. In addition, CoQ(10) significantly improved the ultrastructural preservation of mitochondria and prevented IgG-APS-induced fission mediated by Drp-1 and Fis-1 proteins. In conclusion, the oxidative perturbation in APS patient leukocytes, which is directly related to an inflammatory and pro-atherothrombotic status, relies on alterations in mitochondrial dynamics and metabolism that may be prevented, reverted, or both by treatment with CoQ(10).

Clinical Relevance of Nitric Oxide Metabolites and Nitrative Stress in Thrombotic Primary Antiphospholipid Syndrome

Objective.

To assess the role of nitrite (NO2−), nitrate (NO3−), and nitrative stress in thrombotic primary antiphospholipid syndrome (PAPS).

Methods.

We investigated 46 patients with PAPS: 21 asymptomatic but persistent carriers of antiphospholipid antibodies (PCaPL), 38 patients with inherited thrombophilia (IT), 33 patients with systemic lupus erythematosus (SLE), and 29 healthy controls (CTR). IgG anticardiolipin (aCL), IgG anti-beta2-glycoprotein I (anti-ß2-GPI), IgG anti-high density lipoprotein (aHDL), IgG anti-apolipoprotein A-I (aApoA-I), crude nitrotyrosine (NT) (an indicator of nitrative stress), and high sensitivity C-reactive protein (CRP) were measured by immunoassays. Plasma nitrite (NO2−), nitrate (NO3−), and total antioxidant capacity (TAC) were measured by colorimetric spectroscopic assays.

Results.

Average plasma NO2−was lower in PAPS, PCaPL, and IT (p < 0.0001); average NO3−was highest in SLE (p < 0.0001), whereas average NT was higher in PAPS and SLE (p = 0.01). In thrombotic PAPS, IgG aCL titer and number of vascular occlusions negatively predicted NO2−(p = 0.03 and p = 0.001, respectively), whereas arterial occlusions and smoking positively predicted NO3−(p = 0.05 and p = 0.005), and CRP positively predicted NT (p = 0.004). In the PCaPL group IgG aCL negatively predicted NO3−(p = 0.03). In the SLE group IgG aCL negatively predicted NO2−(p = 0.03) and NO3−(p = 0.02).

Conclusion.

PAPS is characterized by decreased NO2−in relation to type and number of vascular occlusions and to aPL titers. Nitrative stress and low grade inflammation are linked phenomena in PAPS and may have implications for thrombosis and atherosclerosis.