Antioxidant susceptibility of pathogenic pathways in subjects with antiphospholipid antibodies: a pilot study

Evaluation of thiol/disulfide hemostasis and serum Ischemia modified albumin as oxidative stress biomarkers in systemic lupus erythematosus patients: Relationship with major organ involvement and disease activity

OBJECTIVES

We aimed to compare thiol/disulfide hemostasis and serum ischemia-modified albumin (IMA) levels, which are indicators of oxidative stress (OS), in patients with systemic lupus erythematosus (SLE), with the healthy control (HC) group and to evaluate the relationship of these parameters with disease activity and major organ involvement.

MATERIAL-METHODS

Eighty-four SLE patients and 96 HCs were included in this study. The disease activity of SLE patients was calculated using The Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). Patients with SLEDAI-2K ≤ 5 were classified as low disease activity (LDA) and those with SLEDAI-2K > 6 as high disease activity (HDA). Thiol/disulfide hemostasis was evaluated using a new automated method and natural thiol (NT), total thiol (TT), disulfide (SS) levels, SS/NT, SS/TT, NT/TT ratios, and serum IMA levels were recorded.

RESULTS

NT and TT levels were significantly lower (490.11 ± 123.61 vs 536.96 ± 86.05, p = 0.003) (532.56 ± 125.80 vs 565.72 ± 89.82, p = 0.046), SS level (21.22 ± 11.75 vs 13.37 ± 9.31, p < 0.001) was higher, and SS/TT (4.64 ± 2.93 vs 2.52 ± 1.82, p < 0.001) and SS/NT (4.12 ± 2.33 vs 2.35 ± 1.59, p < 0.001) ratios were significantly higher in SLE patients compared to HCs. IMA values were not different between the two groups (p = 0.920). NT (449.84 ± 136.98 vs 520.32 ± 104.11, p = 0.012) and TT levels (492.01 ± 138.45±562.97 ± 107.09, p = 0.013) were significantly lower and serum IMA levels (0.802 ± 0.089 vs 0.764 ± 0.040, p = 0.023) were significantly higher in SLE patients with HDA than in LDA patients. There was a weak negative correlation between NT (r = -0.284, p=0.009) (r = -0.291, p = 0.007) and TT levels (r = -0.281, p = 0.010) (r = -0.289, p = 0.008) and a weak positive correlation between IMA levels (r = 0.279, p = 0.011) (r = 0.263, p = 0.016) and SLEDAI-2K, and major organ involvement.

CONCLUSION

It is thought that thiol/disulfide hemostasis and IMA levels may be used as ideal biomarkers of OS in SLE patients and may reflect the disease activity and major organ involvement.

Oxidative Stress in the Pathogenesis of Antiphospholipid Syndrome: Implications for the Atherothrombotic Process

Atherothrombosis is a frequent complication of the clinical history of patients with antiphospholipid syndrome (APS). Both atherothrombosis and APS are characterized by increased oxidative stress. Oxidative modifications are implicated in the formation of antiphospholipid antibodies, which in turn may favour the oxidative imbalance by increasing the production of reactive oxidant species (ROS) or by a direct interaction with pro-oxidant/antioxidant enzymes. As a result of these processes, APS patients suffer from an oxidative imbalance that may contribute to the progression of the atherosclerotic process and to the onset of ischemic thrombotic complications. The aim of this review is to describe mechanisms implicated in the formation of ROS in APS patients and their involvement in the atherothrombotic process. We also provide an overview of potential therapeutic approaches to blunt oxidative stress and to prevent atherothrombotic complications in these patients.

Antiphospholipid Antibodies and Heart Failure with Preserved Ejection Fraction. The Multicenter ATHERO-APS Study

Background. The prevalence of heart failure with preserved ejection fraction (HFpEF) in patients with antiphospholipid syndrome (APS) is unknown. Methods. A prospective multicenter cohort study including 125 patients was conducted: 91 primary APS (PAPS), 18 APS-SLE, and 16 carriers. HFpEF was diagnosed according to the 2019 European Society of Cardiology criteria: patients with ≥5 points among major and minor functional and morphological criteria including NT-ProBNP > 220 pg/mL, left atrial (LA) enlargement, increased left ventricular filling pressure. Results. Overall, 18 (14.4%) patients were diagnosed with HFpEF; this prevalence increased from 6.3% in carriers to 13.2% in PAPS and 27.8% in APS-SLE. Patients with HFpEF were older and with a higher prevalence of hypertension and previous arterial events. At logistic regression analysis, age, arterial hypertension, anticardiolipin antibodies IgG > 40 GPL (odds ratio (OR) 3.43, 95% confidence interval (CI) 1.09–10.77, p = 0.035), anti β-2-glycoprotein-I IgG > 40 GPL (OR 5.28, 1.53–18.27, p = 0.009), lupus anticoagulants DRVVT > 1.25 (OR 5.20, 95% CI 1.10–24.68, p = 0.038), and triple positivity (OR 3.56, 95% CI 1.11–11.47, p = 0.033) were associated with HFpEF after adjustment for age and sex. By multivariate analysis, hypertension (OR 19.49, 95% CI 2.21–171.94, p = 0.008), age (OR 1.07, 95% CI 1.00–1.14, p = 0.044), and aβ2GPI IgG > 40 GPL (OR 8.62, 95% CI 1.23–60.44, p = 0.030) were associated with HFpEF. Conclusion. HFpEF is detectable in a relevant proportion of APS patients. The role of aPL in the pathogenesis and prognosis of HFpEF needs further investigation.

Triple therapy with pravastatin, low molecular weight heparin and low dose aspirin improves placental haemodynamics and pregnancy outcomes in obstetric antiphospholipid syndrome in mice and women through a nitric oxide-dependent mechanism

OBJECTIVES

A previous pilot study showed that pravastatin supplementation improved pregnancy outcomes in women with obstetric antiphospholipid syndrome (OAPS) that developed placental insufficiency despite standard of care treatment low molecular weight heparin plus low dose aspirin (LMWH + LDA). In this study we investigated the mechanism behind the beneficial effects of the triple therapy LMWH + LDA + pravastatin in improving uteroplacental vascular function and reducing pregnancy complications in OAPS. We hypothesized that nitric oxide (NO) is involved in the vasculoprotective effects of the triple therapy. A mouse model of OAPS that resembles the clinical scenario was used to test this hypothesis.

METHODS

Eleven women with OAPS that developed preeclampsia (PE) and/or intrauterine growth restriction (IUGR) associated with uteroplacental vascular dysfunction despite treatment with LMWH + LDA participated in this study after given informed written consent. Seven women were supplemented with pravastatin at the time abnormal uterine artery Dopplers were detected and 4 remained on LMWH + LDA treatment only. Wire myography was used to identify the mechanisms underpinning the protective effects of the triple therapy in the mouse model of OAPS.

RESULTS

The triple therapy increased serum NO levels, diminished uteroplacental vessels resistance improving placental function and prolonged pregnancies compared to conventional treatment LMWH + LDA, leading to live births in women with OAPS. Comparable to the observations in women, the triple therapy protected pregnancies in OAPS-mice, increasing placental perfusion and pregnancy outcomes. A synergistic vasculoprotective effect of the triple therapy on uterine arteries and aorta was demonstrated in OAPS-mice. LMWH + LDA showed a partial protection on endothelial function. Addition of pravastatin increase eNOS synthesis, expression and activity/signaling leading to a significant increment in nitric oxide (NO) generation, resulting in improved placental vascular function and total protection of pregnancies.

CONCLUSION

LMWH + LDA + PRAV increased serum NO levels and significantly improved placental haemodynamics and maternal and neonatal outcomes in women and mice with OAPS. A role for eNOS/NO in mediating the placental vasculoprotective effects in OAPS-mice was demonstrated, strengthening the concept that impaired NO production is a crucial mediator in the pathogenesis of OAPS and a potential target for pharmacological interventions. The efficacy of pravastatin supplementation should be confirmed in a larger clinical trial.

Antiphospholipid Antibodies and Autoimmune Haemolytic Anaemia: A Systematic Review and Meta-Analysis

The relationship between antiphospholipid antibodies (aPL) and autoimmune haemolytic anaemia (AIHA) has never been systematically addressed. The aim of this study is to assess the link between aPL and AIHA in adult systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). This study performed an EMBASE/PubMed search from inception to June 2019 and meta-analysis using Peto’s odds ratios. The pooled prevalence (PP) of IgG/IgM anticardiolipin (aCL) and lupus anticoagulant (LA) was greater in AIHA +ve than AIHA −ve patients (34.7% vs. 27.6%, p = 0.03; 33.3% vs. 21.8%, p < 0.0001; 20.9% vs. 8.3%, p = 0.01). The PP of AIHA was greater in: (1) IgG and IgM aCL +ve than −ve patients (21.8% vs. 11.1%, p = 0.001 and 18.7% vs. 6.3%, p < 0.0001), (2) in SLE related APS than in primary APS patients (22.8% vs. 3.9% p < 0.0001), (3) in APS +ve than APS −ve SLE patients (23.2% vs. 8.4%, p = 0.01), and (4) in thrombotic APS than non-thrombotic APS/SLE patients (26.8% vs. 10%, p = 0.03). The PP of IgG/IgM aCL and LA was greater in DAT +ve than DAT −ve patients (42.4% vs. 12.8%, p < 0.0001; 26.2% vs. 12.8%, p = 0.03 and 29.2% vs. 15.7%, p = 0.004 respectively). It was found that AIHA prevalence is maximal in SLE with aPL/APS, low-moderate in SLE without aPL and minimal in PAPS. Moreover, AIHA is rightly included among the classification criteria for SLE but not for APS/aPL. The significance of an isolated DAT positivity remains unclear in this setting

Isoprostane in systemic sclerosis: A systematic review and meta-analysis

OBJECTIVES

To further the knowledge of oxidative stress in systemic sclerosis (SSc), we performed a systematic review and meta-analysis on studies measuring isoprostane, a vasoactive agent deriving from arachidonic acid and implicated in the vasculopathy of SSc.

METHODS

Systematic search following the PRISMA guidelines in PubMed and EMBASE between January-1990/December-2017 using the terms: oxidative stress, isoprostane, systemic sclerosis and scleroderma.

RESULTS

After the screening process, 8 studies including 240 SSc patients and 192 controls were included in the systematic review and meta-analysis, 6 investigating urinary and 2 serum isoprostane: random effect meta-analysis revealed isoprostane overgeneration in SSc (p < .001) with wide heterogeneity (I² = 75%). Subgroup analysis on urinary isoprostane favoured excess excretion in SSc (p = .009) with slightly lower heterogeneity (I² = 67%); further subgroup analysis according to unit of measurement revealed no increased isoprostane excretion when expressed as pg/mg creatinine but increased when expressed as pmol/mmol creatinine (p = .05) with medium heterogeneity (I² = 32%). Subgroup analysis on serum isoprostane favoured overproduction in SSc (p < .0001) with no heterogeneity.

CONCLUSION

There is some evidence for isoprostane overgeneration in SSc that confirms the occurrence of oxidative stress in this setting: further prospective studies with specified outcomes are needed to evaluate the prognostic value of this functional biomarker.

New Insights in the Pathophysiology of Antiphospholipid Syndrome

The antiphospholipid syndrome (APS) is an autoimmune disorder characterized by an elevated risk for arterial and venous thrombosis and pregnancy-related morbidity. Since the discovery of the disease in 1980s, numerous studies in cell culture systems, in animal models, and in patient populations have been reported, leading to a deeper understanding of the pathogenesis of APS. These studies have determined that circulating autoantibodies, collectively called antiphospholipid antibodies (aPL), the majority of which recognize cell surface proteins attached to the plasma membrane phospholipids, play a causal role in the development of the disease. The binding of aPL to the cell surface antigens triggers interaction of the complex with transmembrane receptors to initiate intracellular signaling in critical cell types, including platelets, monocytes, endothelial cells, and trophoblasts. Subsequent alteration of various cell functions results in inflammation, thrombus formation, and pregnancy complications. Apolipoprotein E receptor 2 (apoER2), a lipoprotein receptor family member, has been implicated as a mediator for aPL actions in platelets and endothelial cells. Nitric oxide (NO) is a signaling molecule known to exert potent antithrombotic, anti-inflammatory, and anti-atherogenic effects. NO insufficiency and oxidative stress have been linked to APS pathogenesis. This review will focus on the recent findings on how apoER2 and dysregulation of NO production contribute to aPL-mediated pathologies in APS.

Clinical relevance of antiphospholipid antibodies in systemic sclerosis: A systematic review and meta-analysis

OBJECTIVE

To evaluate the clinical relevance of antiphospholipid antibodies (aPL) in systemic sclerosis (SSc).

METHODS

A systematic search of EMBASE and PubMed databases from January 1983 to July 2016 was carried out according to PRISMA guidelines whereas Peto׳s odds ratio (OR) for rare events was used for the meta-analysis.

RESULTS

The pooled prevalence of participants positive for IgG and IgM anticardiolipin (aCL) antibodies was higher in SSc than controls (12.8% vs 1.6% and 7.8% vs 0.6%; p < 0.0001 for both) as was that of IgG and IgM anti-beta-2-glycoprotein-I antibodies (aβ₂GPI) (6.1% vs 0.58%, p < 0.0001; 3.5% vs 0.3%, p = 0.001). The pooled prevalence of pulmonary arterial hypertension (PAH) was more common in SSc positive than negative patients for aCL (IgG/IgM combined) (26.5% vs 10.9%, p < 0.0001) whereas the pooled prevalence of renal disease (RD) was more common in IgG aCL positive than negative patients (36.3% vs 10.9%, p = 0.02). The pooled prevalence of thrombosis was higher in IgG aCL, IgM aCL, and IgM aβ₂GPI positive than negative SSc patients (12.6% vs 1.4%, p < 0.0001), (15.1% vs 2.7%, p = 0.002) and (15% vs 0.78%, p = 0.009), respectively. The pooled prevalence of digital infarction/ischemia (DI) was higher in IgG aCL and IgM positive than negative SSc (52.8% vs 39.8%, p = 0.002) and (68.1% vs 29%, p = 0.07).

CONCLUSIONS

A strong relationship exists between aCL and aβ₂GPI of IgG/IgM isotype and SSc; patients positive for these antibodies are more likely to suffer from PAH, RD, thrombosis, and DI. However, data expressed as frequency of aPL positive patients rather than average antibody titers preclude further insight into the relevance of these assumptions.

Antiphospholipid antibodies are induced by in vitro fertilization and correlate with paraoxonase activity and total antioxidant capacity of plasma in infertile women

The objectives of this study were to determine whether antiphosholipid antibodies are associated with in vitro fertilization (IVF), and assess the potential biological effects of these antibodies. Sera from seventy infertile women (18 before IVF, 13 submitted to one IVF cycle and 39 after three cycles) and 28 healthy controls were collected. Anticardiolipin (anti-CL) and antiphosphatidylserine (anti-PS) antibodies, paraoxonase (PON) and Total Anti-oxidant Capacity of plasma (TAC) were measured. Anti-CL and anti-PS titres were significantly increased in treated patients compared with patients before treatment or controls ( P < 0.001). There were no differences regarding anti-CL and anti-PS titres between controls and untreated patients nor when different types of infertility were considered. PON activity and TAC were significantly reduced in treated patients when compared to untreated and controls ( P < 0.001; P < 0.002). PON correlated inversely with anti-CL and anti-PS IgG ( r = 20.734; P < 0.001) and directly with TAC ( r = 0.720, P < 0.001). In conclusion PON activity is decreased in women submitted to IVF treatment and is associated with the presence of antiphospholipid antibodies. These factors might contribute to the increased oxidative status found in these patients.

oxLDL/β2GPI/anti-β2GPI complex induced macrophage differentiation to foam cell involving TLR4/NF-kappa B signal transduction pathway

Macrophage-derived foam cell formation is a hallmark of atherosclerosis. It has been reported that oxidized low density lipoprotein (oxLDL) inducing formation of foam cells and expression of inflammatory molecules are partly mediated by toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) pathway. However, whether oxLDL/β2-glycoprotein I/anti-β2-glycoprotein I (oxLDL/β2GPI/anti-β2GPI) complex enhanced formation of foam cells involving TLR4/NF-κB pathway or not has never been explored. In the current study, we focused on investigating the transformation of peritoneal macrophages from BALB/c mice into foam cells induced by the three complexes, and the involvement of TLR4 as well as its downstream signal molecule NF-κB. The results showed that treatment of macrophages with oxLDL/β2GPI/anti-β2GPI complex could markedly increase intracellular lipid loading and expression of TLR4, phosphorylated NF-κB p65 (p-NF-κB p65), monocyte chemoattractant protein-1 (MCP-1), as well as tissue factor (TF). The oxLDL and oxLDL/β2GPI/anti-β2GPI complex induced formation of foam cells and expression of p-NF-κB p65 were significantly reduced, while macrophages were pre-treated with TLR4 inhibitor TAK-242. Meanwhile, both TAK-242 and NF-κB inhibitor PDTC could remarkably inhibit oxLDL, oxLDL/β2GPI/anti-β2GPI complex, as well as LPS increased MCP-1 and TF levels. Nevertheless, β2GPI/anti-β2GPI complex-induced MCP-1 and TF mRNA expression were inhibited by TAK-242 rather than PDTC, although TF activity was significantly reduced by both of the inhibitors. In conclusion, our results indicate that oxLDL/β2GPI/anti-β2GPI complex could enhance the conversion of macrophages into foam cells and the process may be at least partly mediated by TLR4/NF-κB pathway, which may contribute to the accelerated development of atherosclerosis in APS.

Inhibition of nitric oxide and antiphospholipid antibody-mediated thrombosis

The antiphospholipid syndrome (APS) is characterized by recurrent vascular thrombosis, thrombocytopenia, and fetal loss occurring in the presence of antiphospholipid antibodies (aPL). Along with arterial and venous thrombosis and pregnancy complications, patients with APS have an increased risk of myocardial infarction, stroke, and coronary artery disease, resulting from vascular cell dysfunction induced by aPL. Accumulating evidence to date indicates that interactions between circulating aPL and cell surface molecules of target cells, primarily endothelial cells and platelets, underlie the vascular disease phenotypes of APS. However, the molecular basis of APS is poorly understood. Nitric oxide produced by endothelial cells is a key determinant of vascular health that regulates several physiologic processes, including thrombosis, endothelial-leukocyte interaction, vascular cell migration, and the modulation of vascular tone. This review will discuss recent findings that indicate a novel mechanism by which aPL antagonize endothelial cell production of nitric oxide and thereby promote thrombosis.

New Insights into the Molecular Basis of the Antiphospholipid Syndrome

Antiphospholipid syndrome is an autoimmune disease characterized by the presence of circulating antiphospholipid antibodies (aPL) that promote thrombosis, pregnancy complications and cardiovascular diseases. Alterations in the function of vascular cells induced by aPL underlie these outcomes. This review will discuss recent findings that indicate a novel mechanism by which aPL antagonize endothelial cell production of nitric oxide and thereby promote thrombosis.

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.

Atherosclerosis in primary antiphospholipid syndrome

Antiphospholipid syndrome (APS) is the most common cause of acquired thrombophilia, but experimental and clinical evidence accumulated over the years suggest that the clinical manifestations of APS go beyond those of a simple hypercoagulable state. Although still a controversial topic, the elevated risk of atherosclerosis in systemic lupus erythematosus seems little accounted for by the presence of antiphospholipid antibodies, whereas premature atherosclerosis has been addressed in few series of patients with primary APS. The available data in primary APS suggest that traditional risk factors for atherosclerosis are less involved in arterial disease, rather antiphospholipid antibodies appear as major players. Their effect on the coagulation system, the vessel wall and on the antioxidant/oxidant balance impairs vascular homeostasis, leading to premature arterial thickening.

Immunogenic oxidized low-density lipoprotein/beta2-glycoprotein I complexes in the diagnostic management of atherosclerosis

Oxidized low-density lipoprotein (oxLDL) promotes atherosclerosis through a complex interaction of inflammatory and immunologic factors that lead to macrophage lipid uptake and foam cell formation. OxLDL interacts with beta2-glycoprotein I (beta2GPI) forming oxLDL/beta2GPI complexes. These complexes may be formed in the arterial intima during atherogenesis and released into the circulation. Autoantibodies against oxLDL/beta2GPI complexes have been demonstrated in patients with systemic lupus erythematosus and/or antiphospholipid syndrome, and shown to be significantly associated with arterial thrombosis. The observation that monoclonal autoantibodies against oxLDL/beta2GPI complexes significantly increased the oxLDL uptake by macrophages strongly suggests that such IgG autoantibodies are pro-atherogenic. In this article, we review the recent progress in our understanding of LDL oxidation, oxLDL/beta2GPI complex formation, and immune regulation of atherogenesis.

Autoimmune-mediated atherothrombosis

Autoimmune vascular inflammation and oxidative stress (lipid peroxidation) are common in systemic autoimmune diseases and contribute to the oxidative modification of low-density lipoprotein (oxLDL) and oxLDL/beta2GPI complex formation. Circulating oxLDL/beta2GPI complexes have been detected in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). The presence of antibodies to oxLDL/beta2GPI complexes indicates that these complexes are immunogenic, and the coexistence of complexes and antibodies has pointed to an active proatherogenic role in the development of autoimmune vascular complications. Immunohistochemical staining of atherosclerotic lesions suggest that these complexes are formed in the arterial wall and released into circulation. The in vitro macrophage uptake of oxLDL/beta2GPI complexes was significantly increased in the presence of antiphospholipid antibodies, either beta2GPI-dependent anticardiolipin or anti-beta2GPI antibodies, suggesting that macrophage Fcgamma receptors are involved in lipid intracellular influx and foam cell formation. These findings provide an explanation for the accelerated development of atherosclerosis seen in SLE and APS. The presence of circulating oxLDL/beta2GPI complexes and IgG antibodies to these complexes indicate significant vascular injury and oxidative stress as well as an active role in autoimmune-mediated atherothrombosis.

The role of oxidative stress in spontaneous abortion and recurrent pregnancy loss: a systematic review

Human reproduction is not considered a highly efficient biological process. Before the end of the first trimester, 30%-50% of conceptions end in spontaneous abortion. Most losses occur at the time of implantation. 15%-20% of clinical pregnancies end in spontaneous abortions. Recurrent pregnancy loss is a frustrating clinical problem both for clinicians and patients. Recurrent pregnancy loss affects 0.5%-3% of women in the reproductive age group, and between 50%-60% of recurrent pregnancy losses are idiopathic. Oxidative stress-induced damage has been hypothesized to play a role in spontaneous abortion, idiopathic recurrent pregnancy loss, hydatidiform mole, defective embryogenesis, and drug-induced teratogenicity. Some studies implicate systemic and placental oxidative stress in the pathophysiology of abortion and recurrent pregnancy loss. Oxidant-induced endothelial damage, impaired placental vascularization and immune malfunction have all been proposed to play a role in the pathophysiology of idiopathic recurrent pregnancy loss. Oxidative stress-induced placental dysfunction may be a common cause of the multifactorial and polygenic etiologies of abortion, recurrent pregnancy loss, defective embryogenesis, hydatidiform mole, and drug-induced teratogenic effects. Oxidative stress-induced modification of phospholipids has been linked to the formation of antiphospholipid antibodies in the antiphospholipid syndrome. The objective of this review was to examine the association between oxidative stress, spontaneous abortion and recurrent pregnancy loss, based on the published literature. We conducted an extensive literature search utilizing the databases of Medline, CINAHL, and Cochrane from 1986 to 2005. The following keywords were used: oxidative stress, abortion, recurrent pregnancy loss, reactive oxygen species, antioxidants, fetal development, and embryopathies. We conducted an electronic search, as well as a manual search of cross-references. We have included all studies in the English language found in the literature focusing on oxidative stress and its association with abortions, recurrent pregnancy loss and drug-induced teratogenicity. The role of antioxidant vitamins for primary prevention of oxidative stress-induced pathologies needs to be investigated further.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to state that the causes of spontaneous and recurrent abortion are multifaceted, however, some of the causes may be preventable and also explain that the role of oxidative stress during pregnancy and adverse pregnancy outcomes has a basis in pathophysiology, although the role of oxidative stress and the treatment of oxidative stress during or before pregnancy remains speculative.

Accelerated atheroma in the antiphospholipid syndrome

Increased cardiovascular morbidity and mortality due to the pre-mature or accelerated development of atherosclerosis has been reported in patients with systemic autoimmune diseases such as systemic lupus erythematosus. These findings motivated a great deal of research into the role of autoimmunity in atherogenesis. The relationship between atherosclerosis and cholesterol metabolism to atherosclerosis has been well established. However, the participation of newer inflammatory and immunologic mechanisms are emerging as relevant factors for the initiation and progression of atherosclerotic lesions.

Antiphospholipid syndrome in systemic lupus erythematosus: is the whole greater than the sum of its parts?

This article compares the manifestations of systemic lupus erythematosus (SLE) in the presence and absence of antiphospholipid antibodies (aPLs), the hallmark autoantibodies of antiphospholipid syndrome (APS). The combination of SLE and APS appears to be of greater concern than either entity alone. APS complicates SLE by adding a vaso-occlusive factor to the inflammatory component that adversely affects the prognosis of those who have lupus and aPLs. The increase in both morbidity and mortality when both are present has significant therapeutic implications. Anticoagulation may be a safer and more appropriate therapeutic option than instituting a regimen of corticosteroids and immunosuppressive agents with all their attendant adverse effects. It falls upon the physician to clearly define the disease entity and fully evaluate the disease process.

Human monoclonal IgG anticardiolipin antibodies induce nitric oxide synthase expression

OBJECTIVE

Antiphospholipid antibodies are associated with increased risk of thrombosis, particularly as in antiphospholipid syndrome. This study aims to determine the acute effects of anticardiolipin antibodies on nitric oxide production and vascular function.

METHODS

Ex vivo aortic rings from male Sprague Dawley rats were incubated with IgG monoclonal anticardiolipin antibody (IS4) or a non-specific IgG control. In organ baths, response to phenylephrine and acetlycholine was determined alone and with nitro-L-arginine methyl ester (L-NAME), 1,400 W, D-arginine, L-arginine, sodium nitroprusside and cardiolipin. In vivo antibodies were injected into anaesthetised, spontaneously breathing male Sprague Dawley rats. Haemodynamic variables and serum nitric oxide were measured. Immunohistochemistry for iNOS and eNOS was performed in kidney vessels.

RESULTS

Phenylepherine contraction was decreased in the IS4 group compared to controls (p < 0.001). L-NAME, 1,400 W and cardiolipin, abolished this effect. L-Arginine caused significant relaxation in the IS4 group (p = 0.005). Mean arterial pressure in rats injected with IS4 was reduced compared to IgG and saline controls (p < 0.001). NO in plasma increased significantly after IS4 administration (p < 0.001). Immunohistochemistry showed increased iNOS expression in kidney arteries in the IS4 group, with no change in eNOS.

CONCLUSION

Anticardiolipin antibodies induce NO production acutely via increased expression of iNOS in both ex vivo and in vivo models.

Antiphospholipid antibodies are associated with enhanced oxidative stress, decreased plasma nitric oxide and paraoxonase activity in an experimental mouse model

OBJECTIVE

Oxidative stress contributes to atherosclerosis, and evidence of enhanced oxidative stress exists in antiphospholipid syndrome (APS). In a non-lupus murine model, we evaluated whether anticardiolipin (aCL) antibodies could affect the oxidant/antioxidant balance as an early biochemical step of APS.

METHODS

Hybridomas producing human and murine aCL and anti-beta(2)-glycoprotein I (abeta2-GPI) monoclonal antibodies were injected into three groups of five female BALB/c severe combined immunodeficiency (SCID) mice. Corresponding hybridomas secreting non-antiphospholipid antibodies of the same isotype were employed as controls. Sera and organs were collected after 30 days. Paraoxonase (PON) activity, peroxynitrite, superoxide, nitric oxide (NO) and nitrotyrosine were measured in plasma. Expression of endothelial nitric oxide synthase and inducible nitric oxide synthase (iNOS) was assessed by western blot and immunohistochemistry.

RESULTS

PON activity and NO (sum of nitrate and nitrite) levels were reduced in the human aCL IgG group (P<0.002 and P<0.04, respectively), whilst peroxynitrite and superoxide and expression of total antioxidant capacity of plasma were increased (P<0.01). PON and NO were decreased in the murine abeta2-GPI IgG and IgM aCL groups (P<0.03 and P<0.05, respectively). Nitrotyrosine was elevated in the human aCL IgG group (P<0.03). Western blotting showed reduced iNOS expression in the hearts of the IgG aCL group, confirmed by immunostaining. PON inversely correlated with IgG aCL titres (P<0.001), superoxide (P<0.008) and peroxynitrite levels (P<0.0009). Peroxynitrite and total IgG aCL were independent predictors of PON (P<0.0009 and P<0.02, respectively). Superoxide was the only independent predictor of NO (P<0.008) and of nitrotyrosine (P<0.002).

CONCLUSION

aCL antibodies are associated with the decreased PON activity and reduced NO that may occur in the preclinical phase of APS.

Oxidative stress and its implications in female infertility – a clinician's perspective

Reactive oxygen species (ROS) have a role in the modulation of gamete quality and gamete interaction. Generation of ROS is inherent in spermatozoa and contaminating leukocytes. ROS influence spermatozoa, oocytes, embryos and their environment. Oxidative stress (OS) mediates peroxidative damage to the sperm membrane and induces nuclear DNA damage. ROS can modulate the fertilizing capabilities of the spermatozoa. There is extensive literature on OS and its role in male infertility and sperm DNA damage and its effects on assisted reproductive techniques. Evidence is accumulating on the role of ROS in female reproduction. Many animal and human studies have elucidated a role for ROS in oocyte development, maturation, follicular atresia, corpus luteum function and luteolysis. OS-mediated precipitation of pathologies in the female reproductive tract is similar to those involved in male infertility. OS influences the oocyte and embryo quality and thus the fertilization rates. ROS appears to play a significant role in the modulation of gamete interaction and also for successful fertilization to take place. ROS in culture media may impact post-fertilization development, i.e. cleavage rate, blastocyst yield and quality (indicators of assisted reproduction outcomes). OS is reported to affect both natural and assisted fertility. Antioxidant strategies should be able to intercept both extracellular and intracellular ROS. This review discusses the sources of ROS in media used in IVF-embryo transfer and strategies to overcome OS in oocyte in-vitro maturation, in-vitro culture and sperm preparation techniques.

Oxidative stress in systemic lupus erythematosus and antiphospholipid syndrome: a gateway to atherosclerosis

Vascular disease and atherosclerosis are significant clinical features of systemic lupus erythematosus and antiphospholipid syndrome. Oxidation is one of the major factors responsible for atheroma development in this context. Anticardiolipin antibodies seem to play an important role by inducing nitric oxide and superoxide production, resulting in enhanced levels of plasma peroxynitrite, which is a powerful pro-oxidant substance. Furthermore, direct interference of these antibodies with paraoxonase activity, a high-density lipoprotein-related anti-oxidant enzyme, would contribute to the oxidative stress found in these conditions. The accelerated process of atherogenesis found in these diseases can represent a useful model for the study of atherosclerosis in the general population.

Atherosclerosis, oxidative stress and auto-antibodies in systemic lupus erythematosus and primary antiphospholipid syndrome

Overwhelming evidence spanning three decades has consistently shown that coronary artery disease is a major cause of morbidity and mortality in Systemic Lupus Erythematosus. Traditionally this was explained by abnormalities of the lipid profile induced by prolonged steroid treatment. Subsequently, antiphospholipid antibodies were presented as an additional cardiovascular risk factor. Recently, antibodies towards high-density lipoprotein and antiapolipoprotein A-I have been identified. These, together with anti-beta2 glycoprotein-1, interfere with the major antioxidant defence of patients with SLE and with primary antiphospholiqid syndrome exposing them to the atherogenic potential of enhanced oxidative stress. The present review discusses how the latter auto-antibodies, together with abnormalities of their target lipid auto-antigens, could enhance the risk of atherosclerosis in SLE and APS.

Acquired thrombophilias and pregnancy

Acquired thrombophilias are hypercoagulable states secondary to various aetiologies. In particular, during pregnancy the risks are exaggerated due to the underlying physiological changes. The commonest cause of acquired thrombophilia in pregnancy is antiphospholipid syndrome. Antiphospholipid syndrome (APS) is a complex multisystem disorder that has been associated with varied medical and obstetric complications. The pathogenesis of APS has been further elucidated in recent studies. The two most clinically significant antiphospholipid antibodies that are associated with recurrent pregnancy loss and thromboembolism are anticardiolipin antibodies (aCL) and lupus anticoagulant (LA). The laboratory diagnosis is based on the presence of moderate to high positive aCL and/or LA antibodies. It is crucial that APS is not inappropriately diagnosed as this has implications for counselling and management with thromboprophylaxis during pregnancy. Over the last decade there have been significant changes in the laboratory and clinical criteria for the diagnosis of APS. National and international collaborations have made efforts to standardize the laboratory methods. There have been very few randomized placebo-controlled trials of drug therapy and so not all drug treatment strategies have a strong evidence base. With current management strategies, using low-molecular-weight heparin and aspirin, a greater than 70% live birth rate may be achieved in affected pregnancies. A multidisciplinary approach in the management of these women is vital.

Antiphospholipid Antibody Syndrome

Antiphospholipid antibody syndrome (APS) is a recently defined autoimmune disorder characterized by recurrent vascular thromboses or recurrent pregnancy morbidity; these features are linked to the presence in blood of autoantibodies against negatively charged phospholipids or phospholipid-binding proteins. Thrombosis can occur in any tissue, in veins, arteries, or the microvasculature. Pregnancy morbidity in APS includes miscarriages or premature birth. Criteria that define the major clinical and laboratory features of APS were published in 1999. In patients with antiphospholipid antibodies and prior thrombosis or pregnancy morbidity, there is a high risk of recurrence that persists as long as antiphospholipid antibodies occur in blood. This risk for recurrence of thrombosis or pregnancy morbidity is greatly reduced by preventive anticoagulant therapy. Patients presenting with thrombosis in APS are initially managed in much the same way as are patients with vascular thrombosis owing to other causes. However, in patients with APS, high-intensity anticoagulation is usually needed to prevent recurrences of thrombosis. Thrombosis in APS is often multifactorial, as with non-APS thrombosis. Therefore, in all patients with APS, other reversible risk factors for thrombosis should be sought. The pregnancy outcome of women with APS who have had prior miscarriages is greatly improved by treatment during pregnancy with a combination of heparin and low-dose aspirin.

Treatment and monitoring of patients with antiphospholipid antibodies and thrombotic history (Hughes syndrome)

Patients with Hughes (antiphospholipid) syndrome who develop an initial thrombosis have an increased risk of subsequent thrombotic events. Current therapy to prevent recurrent thrombosis is controversial. While it seems clear that anticoagulant treatment is a better option than anti-aggregants alone, there is no consensus regarding the duration and intensity of oral anticoagulation. The risk of bleeding, the main complication of anticoagulant treatment, and the need for frequent monitoring of the International Normalized Ratio to measure the anticoagulant effect of warfarin concern patients and physicians. In addition, there is some debate about the validity of the International Normalized Ratio in patients with lupus anticoagulant activity. The development of new therapies that target more specific pathogenic mechanisms is highly warranted.

Treatment of the antiphospholipid syndrome

Despite increasing knowledge of the immunology and pathophysiology of the antiphospholipid syndrome, treating this condition remains challenging. Because of a paucity of randomized controlled trials, many of the treatment recommendations are not evidence-based. Retrospective case series suggest that a high level of oral anticoagulation is needed to prevent recurrent thrombosis. The combination of heparin and low-dose aspirin is effective in significantly increasing the chances of a successful pregnancy in woman with recurrent pregnancy failure associated with antiphospholipid antibodies. Primary prevention with aspirin is justified in patients with antiphospholipid antibodies but without a prior history of thrombosis. Interesting and controversial issues in the treatment of the antiphospholipid syndrome include the use of less intensive anticoagulation or antiplatelet agents in some patient subsets, anticoagulation for certain nonstroke neurologic conditions, the role of other agents (hydroxychloroquine, antioxidants), and novel immunomodulatory strategies.