Antiphospholipid syndrome, antiphospholipid antibodies, and atherosclerosis

Impaired endothelial function and increased carotid intima-media thickness in association with elevated von Willebrand antigen level in primary antiphospholipid syndrome

Primary antiphospholipid syndrome (APS) is characterized by venous or arterial thrombotic events and/or recurrent abortions, fetal death, preeclasmpsia, eclampsia in the presence of anticardiolipin antibodies or lupus anticoagulant, in the absence of accompanying diseases. Antiphospholipid antibodies can activate endothelial cells, and were recently implicated in atherosclerosis. To assess potential endothelial impairment and early signs of atherosclerosis, flow-mediated (endothelium-dependent) and nitrate-mediated (endothelium independent) vasodilation, as well as von Willebrand factor antigen level and carotid artery intima-media thickness (IMT) were measured in patients with primary antiphospholipid syndrome and in healthy controls. Flow-mediated vasodilation in patients with primary APS was significantly lower than that of controls (3.43 ± 2.86% versus 7.96 ± 3.57%; P < 0.0001). We also found significantly higher von Willebrand antigen levels in patients with primary APS than in the control group (157.91 ± 52.45% versus 125.87 ± 32.8%; P = 0.012). Moreover, carotid artery IMT was significantly larger in the primary APS group compared to controls (0.714 ± 0.2 mm versus 0.58 ± 0.085 mm; P = 0.0037). Our results reflect ongoing endothelial damage and accelerated atherosclerosis in patients with primary APS, and suggest that vasoprotective therapy may be beneficial in the treatment of these patients. Lupus (2007) 16, 497—503.

Cardiovascular involvement in autoimmune diseases

Autoimmune diseases (AD) represent a broad spectrum of chronic conditions that may afflict specific target organs or multiple systems with a significant burden on quality of life. These conditions have common mechanisms including genetic and epigenetics factors, gender disparity, environmental triggers, pathophysiological abnormalities, and certain subphenotypes. Atherosclerosis (AT) was once considered to be a degenerative disease that was an inevitable consequence of aging. However, research in the last three decades has shown that AT is not degenerative or inevitable. It is an autoimmune-inflammatory disease associated with infectious and inflammatory factors characterized by lipoprotein metabolism alteration that leads to immune system activation with the consequent proliferation of smooth muscle cells, narrowing arteries, and atheroma formation. Both humoral and cellular immune mechanisms have been proposed to participate in the onset and progression of AT. Several risk factors, known as classic risk factors, have been described. Interestingly, the excessive cardiovascular events observed in patients with ADs are not fully explained by these factors. Several novel risk factors contribute to the development of premature vascular damage. In this review, we discuss our current understanding of how traditional and nontraditional risk factors contribute to pathogenesis of CVD in AD.

Cardiovascular disease in rheumatoid arthritis: a systematic literature review in latin america

Background. Cardiovascular disease (CVD) is the major predictor of poor prognosis in rheumatoid arthritis (RA) patients. There is an increasing interest to identify "nontraditional" risk factors for this condition. Latin Americans (LA) are considered as a minority subpopulation and ethnically different due to admixture characteristics. To date, there are no systematic reviews of the literature published in LA and the Caribbean about CVD in RA patients. Methods. The systematic literature review was done by two blinded reviewers who independently assessed studies for eligibility. The search was completed through PubMed, LILACS, SciELO, and Virtual Health Library scientific databases. Results. The search retrieved 10,083 potential studies. A total of 16 articles concerning cardiovascular risk factors and measurement of any cardiovascular outcome in LA were included. The prevalence of CVD in LA patients with RA was 35.3%. Non-traditional risk factors associated to CVD in this population were HLA-DRB1 shared epitope alleles, rheumatoid factor, markers of chronic inflammation, long duration of RA, steroids, familial autoimmunity, and thrombogenic factors. Conclusions. There is limited data about CVD and RA in LA. We propose to evaluate cardiovascular risk factors comprehensively in the Latin RA patient and to generate specific public health policies in order to diminish morbi-mortality rates.

Comparative assessment of vascular function in autoimmune rheumatic diseases: considerations of prevention and treatment

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to increased cardio- and cerebrovascular disease risk. Traditional risk factors, as well as the role of systemic inflammation including cytokines, chemokines, proteases, autoantibodies, adhesion receptors and others have been implicated in the development of these vascular pathologies. The characteristics of vasculopathies may significantly differ depending on the underlying disease. While classical accelerated atherosclerosis has been associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or spondyloarthropathies (SpA), obliterative vasculopathy may rather be characteristic for systemic sclerosis (SSc) or mixed connective tissue disease (MCTD). Antiphospholipid antibodies have been implicated in vasculopathies underlying SLE, antiphospholipid syndrome (APS), RA and MCTD. There is also heterogeneity with respect to inflammatory risk factors. Cytokines, such as tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6) and immune complexes are primarily involved in arthritides, such as RA, SpA, as well as in SLE. On the other hand, autoantibodies including anti-oxLDL anti-cardiolipin and anti-β2GPI are rather involved in SLE- and APS-associated vasculopathies. Regarding the non-invasive assessment of vascular function, endothelial dysfunction, overt atherosclerosis and vascular stiffness may be indicated by brachial artery flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT) and aortic pulse-wave velocity (PWV), respectively. These abnormalities have been described in most inflammatory rheumatic diseases. While ccIMT and stiffness are relatively stable, FMD may be influenced by many confounding factors. In addition to traditional vasculoprotection, immunosuppressive agents including corticosteroids, traditional and biologic DMARDs may have significant vascular and metabolic effects. The official EULAR recommendations on the assessment and management of cardiovascular disease in arthritides have just been published, and similar recommendations in connective tissue diseases are to be developed soon.

Effects of anti-cardiolipin antibodies and IVIg on annexin A5 binding to endothelial cells: implications for cardiovascular disease

OBJECTIVES

Anti-phospholipid antibodies (aPL), including anti-cardiolipin antibodies (aCL), are risk factors for cardiovascular disease (CVD) in the general population and in patients with the anti-phospholipid syndrome (APS; Hughes syndrome). APS may be primary but is also common in patients with systemic lupus erythematosus (SLE). The anti-coagulant protein annexin A5 (ANXA5) is implicated in CVD by interfering with phospholipids and aPL.

METHODS

ANXA5 binding to human umbilical venous endothelial cells (HUVECs) was determined by flow cytometry.

RESULTS

When cells were cultured in serum from APS patients with a high aPL titre (aPL-S), binding of ANXA5 to HUVECs was reduced. Monoclonal immunoglobulin (Ig)G aPL against cardiolipin (mAb-CL) dose-dependently reduced ANXA5 binding to endothelium. Preincubation of intravenous (IV)Ig at therapeutically relevant doses with aPL-S and mAb-aCL restored ANXA5 binding to comparable levels when normal healthy serum (NHS) was used. By contrast, IVIg per se had the capacity to reduce ANXA5 binding to endothelium when added to NHS (but not to aPL-S).

CONCLUSIONS

Decreased ANXA5 binding to endothelium, mediated by aPL, is a novel mechanism of atherothrombosis that can be countered by IVIg in vitro. IVIg per se could, to a lesser degree, cause decreased ANXA5 binding in NHS, which raises the possibility that some antibodies in IVIg can be involved in a side-effect reported in IVIg treatment, namely atherothrombosis and CVD. Increasing ANXA5 binding, either by addition of ANXA5 or by use of neutralizing antibodies in IVIg, represents a possible therapeutic strategy that deserves further study.

Anti-cardiolipin antibodies and endothelial function in patients with coronary artery disease

Endothelial dysfunction is considered an important marker in atherosclerosis, having a prognostic value. Antiphospholipid antibodies are considered prothrombotic and have recently been reported to be associated also with atherosclerosis. This study was conducted to investigate a possible association of endothelial dysfunction with various antiphospholipid autoantibodies in healthy subjects and patients with cardiovascular disease. In a single-center, prospective study, 2 groups were included. The study group included patients with cardiovascular diseases (coronary disease and/or cerebrovascular disease) and healthy subjects without apparent heart disease who were referred to the endothelial function laboratory for the assessment of endothelial function. Flow-mediated dilatation, which indicates endothelial function, and nitroglycerin-mediated vasodilatation, which indicates smooth-muscle function, were measured. The 2 groups were evaluated for autoantibodies, including anticardiolipin (aCL; immunoglobulin G [IgG], immunoglobulin M [IgM], and immunoglobulin A [IgA]), antinuclear antibody, anti-beta2-glycoprotein I (IgG, IgM, and IgA), and oxidized low-density lipoprotein. One hundred seven subjects were included in the study: 45 patients (42%) and 62 healthy controls (58%). Flow-mediated dilatation was significantly lower in patients compared with healthy controls (8.0 +/- 9.5% vs 8.0 +/- 13.5%, p = 0.012). In addition, nitroglycerin-mediated vasodilatation was nonsignificantly lower in patients than in healthy controls (8.0 +/- 13.4% vs 11.0 +/- 16.7%, p = 0.084). The mean levels of anti-beta2-glycoprotein I (IgG, IgM, and IgA), aCL (IgM and IgA), antinuclear antibody, and oxidized low-density lipoprotein were not different between groups. However, the mean level of IgG aCL was significantly higher in patients than in healthy controls. In conclusion, in accordance with previous reports of an association between aCL and atherosclerosis, patients with cardiovascular disease had endothelial dysfunction and elevated levels of aCL.

Prevalence of Antiphospholipid and Antioxidized Low-Density Lipoprotein Antibodies in Rheumatoid Arthritis

Antiphospholipid antibodies characterize the antiphospholipid syndrome (APS), but they can also be found in various autoimmune, infectious, and malignant conditions. This study's objectives were to detect the prevalence of antiphospholipid and antioxidized low-density lipoprotein (anti-oxLDL) antibodies among patients with rheumatoid arthritis (RA) who did not have clinical manifestations of APS. Using a standard enzyme-linked immunosorbent assay (ELISA), we evaluated the levels of immunoglobulin G (IgG) and IgM anticardiolipin, IgG, and IgM anti-beta-2-glycoprotein-I (anti-beta(2)GPI), and anti-oxLDL autoantibodies in 82 patients with RA. The cutoff levels for detecting these autoantibodies were 15 IgG phospholipid units (GPL), 15 IgM phospholipid units (MPL), and 25 ELISA units (EU)/mL, respectively. Elevated levels of IgG anticardiolipin antibodies were detected in 17 of 82 (21%) RA patients, including 10 with low levels of IgG anticardiolipin and 7 with medium to high levels of anticardiolipin autoantibodies. IgM anticardiolipin was found in only 1 (1%) patient, and both IgG and IgM anti-beta(2)GPI were found in 3 (4%) patients with RA. Elevated levels of anti-oxLDL antibodies were found in 8 (10%) patients, 4 of whom also had elevated levels of IgG anticardiolipin. We conclude that IgG anticardiolipin autoantibodies can be found in about one-fifth of RA patients who do not have clinical manifestations of APS. Whether the presence of anticardiolipin signifies increased risk for thrombosis and atherosclerosis in these patients should be studied further.

Antiphospholipid antibodies: are they pro-atherogenic or an epiphenomenon of atherosclerosis?

Antiphospholipid antibodies are the hallmark of the antiphospholipid syndrome which is characterized by thrombosis. There are currently data supporting an association between these autoantibodies and atherosclerosis as well. Human studies suggest that anti-cardiolipin and anti-beta2-glycoprotein-I antibodies are elevated in patients having coronary artery disease compared with controls. Anti-cardiolipin antibodies are also associated with typical chest pain, significant coronary artery stenosis on angiography and prediction of myocardial infarction. Laboratory studies and murine models support the pro-atherogenic role of these autoantibodies, as they are involved in uptake of oxidized LDL into macrophages, and immunization of mice with them results in enhanced atherosclerosis. There is some evidence that high anti-beta2-glycoprotein-I antibodies can present a risk factor for atherosclerosis, but more epidemiological data are required in order to confirm whether the pro-atherogenic properties of anti-phospholipid antibodies signifies an independent risk factor for atherosclerosis and its complications.

Antiprothrombin antibodies are associated with pregnancy loss in patients with the antiphospholipid syndrome

OBJECTIVE

To document the clinical association between the history of pregnancy loss in patients with the diagnosis of primary or secondary antiphospholipid syndrome (APS) and the presence of different antiprothrombin antibody subtypes [immunoglobulin G (IgG), IgM and IgA] in a cohort of patients with APS.

METHODS

Records of 170 female patients with primary APS, or APS secondary to systemic lupus erythematosus (SLE) or secondary to other autoimmune diseases were studied.

RESULTS

In female APS patients with IgG antiprothrombin antibodies (n = 105) significant associations to pregnancy loss (p < 0.0001), early pregnancy loss (p < 0.0001) and a negative association to thrombocytopenia (p < 0.01) could be identified. In the group of patients with IgG antiprothrombin antibodies and at least one pregnancy (n = 84) a significant association with pregnancy loss (p < 0.005) and especially with early pregnancy loss (p < 0.0001) was demonstrated. No association with other immunoglobulin subtypes of antiprothrombin antibodies could be documented. In the subgroup of patients with primary APS and at least one pregnancy in the history, pregnancy loss (p < 0.005) and early pregnancy loss (p < 0.0001) were found to be highly associated with the presence of IgG antiprothrombin antibodies. IgG antiprothrombin antibodies represent the highest independent risk factor for pregnancy loss with an odds ratio of 4.5. There was no statistically significant association with venous or arterial thrombosis in all IgG antiprothrombin antibody positive patients.

CONCLUSION

The results of this study document the association of IgG antiprothrombin antibodies with pregnancy loss and in particular early pregnancy loss in a large and well-characterized cohort of patients. We would recommend routine testing for antiprothrombin antibodies in young female patients with APS.

Atherosclerosis

Is atherosclerosis a cellular or humoral mediated autoimmune disease?