Serum osteoprotegerin and its gene polymorphisms in patients with Takayasu's arteritis: a bicentric cross-sectional study

INTRODUCTION

Takayasu's arteritis (TAK) patients are at an elevated risk of metabolic syndrome and cardiovascular diseases (CVD). Currently, there are no well-validated biomarkers to assess this risk in this population. Previous research in different cohorts has linked serum levels of osteoprotegerin (OPG) and its polymorphisms to accelerated atherosclerosis and a marker of poor prognosis in CVD. Thus, we assessed this protein as a potential biomarker of CVD in TAK patients.

OBJECTIVES

To evaluate the serum levels of OPG and its SNPs (single nucleotide polymorphisms) in TAK patients and healthy controls, and to associate these parameters with clinical data.

METHODS

This bicentric cross-sectional study included TAK patients who were compared with healthy individuals (control group). The serum levels of OPG and the frequency of OPG SNPs [1181G > C (rs2073618), 245 A > C (rs3134069), 163T > C (rs3102735), and 209 C > T (rs3134070)] were compared between the both groups and associated with clinical data.

RESULTS

In total, 101 TAK patients and 93 controls were included in the study. The serum levels of OPG (3.8 ± 1.9 vs. 4.3 ± 1.8pmol/L, respectively; P = 0.059), and its four polymorphisms were comparable between both groups. In an additional analysis of only TAK patients, serum OPG levels and its four genes were not associated with any CVD parameters, except for higher OPG levels among patients without dyslipidemia.

CONCLUSION

No significant differences were observed in serum OPG levels or in the genotype frequencies of OPG SNPs between the patient and control groups. Similarly, no correlation was found between laboratory parameters and clinical data on CVD risk in TAK patients.

Novel Surrogate Markers of Cardiovascular Risk in the Setting of Autoimmune Rheumatic Diseases: Current Data and Implications for the Future

Patients suffering from rheumatologic diseases are known to have an increased risk for cardiovascular disease (CVD). Although the pathological mechanisms behind this excess risk have been increasingly better understood, there still seems to be a general lack of consensus in early detection and treatment of endothelial dysfunction and CVD risk in patients suffering from rheumatologic diseases and in particular in those who haven't yet shown symptoms of CVD. Traditional CVD prediction scores, such as Systematic Coronary Risk Evaluation (SCORE), Framingham, or PROCAM Score have been proposed as valid assessment tools of CVD risk in the general population. However, these risk calculators developed for the general population do not factor in the effect of the inflammatory burden, as well as other factors that can increase CVD risk in patients with rheumatic diseases, such as glucocorticoid therapy, abnormal lipoprotein function, endothelial dysfunction or accelerated atherosclerosis. Thus, their sole use could lead to underestimation of CVD risk in patients with rheumatic diseases. Therefore, there is a need for new biomarkers which will allow a valid and early assessment of CVD risk. In recent years, different research groups, including ours, have examined the value of different CVD risk factors such as carotid sonography, carotid-femoral pulse wave velocity, flow-mediated arterial dilation and others in the assessment of CVD risk. Moreover, various novel CVD laboratory markers have been examined in the setting of autoimmune diseases, such as Paraoxonase activity, Endocan and Osteoprotegerin. Dyslipidemia in rheumatoid arthritis (RA) is for instance better quantified by lipoproteins and apolipoproteins than by cholesterol levels; screening as well as pre-emptive carotid sonography hold promise to identify patients earlier, when prophylaxis is more likely to be effective. The early detection of subtle changes indicating CVD in asymptomatic patients has been facilitated through improved imaging methods; the inclusion of artificial intelligence (AI) shows promising results in more recent studies. Even though the pathophysiology of coronary artery disease in patients with autoimmune rheumatic diseases has been examined in multiple studies, as we continuously gain an increased understanding of this comorbidity, particularly in subclinical cases we still seem to fail in the stratification of who really is at risk—and who is not. A the time being, a multipronged and personalized approach of screening patients for traditional CVD risk factors, integrating modern imaging and further CV diagnostic tools and optimizing treatment seems to be a solid approach. There is promising research on novel biomarkers, likewise, methods using artificial intelligence in imaging provide encouraging data indicating possibilities of risk stratification that might become gold standard in the near future. The present review concentrates on showcasing the newest findings concerning CVD risk in patients with rheumatologic diseases and aims to evaluate screening methods in order to optimize CVD risk evaluation and thus avoiding underdiagnosis and undertreatment, as well as highlighting which patient groups are most at risk.

The impact of antimalarial agents on traditional and non-traditional subclinical atherosclerosis biomarkers in systemic lupus erythematosus: A systematic review and meta-analysis

OBJECTIVE

Cardiovascular (CV) morbidity is a well-established problem in systemic lupus erythematosus (SLE). Antimalarial (AM) therapy has been seen as a potential atheroprotective agent. The aim was to assess the impact of AM therapy on traditional and novel atherosclerosis (AT) biomarkers in patients with SLE.

METHODS

A search of MEDLINE, EMbase, and Cochrane library for studies evaluating the impact of AM on AT biomarkers in SLE was conducted. Data extraction included serum, functional and structural traditional and novel biomarkers. A narrative synthesis of the findings and a meta-analysis with random effects was conducted estimating mean differences (MD), OR, HR and 95% CIs.

RESULTS

The search strategy produced 148 articles, of which 64 were extracted for analysis. The MD in VLDL-cholesterol (-10.29, 95% CI -15.35, 5.24), triglycerides (-15.68, 95% CI -27.51, -3.86), and diastolic BP (-3.42, 95% CI -5.62, -1.23) differed significantly in patients on AM therapy compared with those without AM therapy. Patients on AM had a lower prevalence and incidence of diabetes mellitus than patients not on AM (HR: 0.39, 95% CI 0.17, 0.88). HCQ use was associated with lower blood pressure (BP) variability. Structural markers like carotid intima-media thickness (IMT), carotid plaque (CP) and coronary artery calcification (CAC) were not influenced by AM. For functional markers like endothelial and arterial stiffness the benefit was unclear. The GRADE approach showed a very low-to-low quality of evidence (QoE) per outcome.

CONCLUSIONS

There is some evidence on the associations between AM therapy and some AT markers. However, the data on which this conclusion was based was of low to very low evidence.

Rabies virus matrix protein targets host actin cytoskeleton: a protein-protein interaction analysis

Multifunctional matrix protein (M) of rabies virus (RABV) plays essential roles in the pathogenesis of rabies infection. Identification of M protein interacting partners in target hosts could help to elucidate the biological pathways and molecular mechanisms involved in the pathogenesis of this virus. In this study, two-dimensional Far-western blotting (2D-Far-WB) technique was applied to find possible matrix protein partners in the rat brainstem. Recombinant RABV M was expressed in Pichia pastoris and was partially purified. Subsequently, 2D-Far-WB-determined six rat brainstem proteins interacted with recombinant M proteins that were identified by mass spectrometry. Functional annotation by gene ontology analysis determined these proteins were involved in the regulation of synaptic transmission processes, metabolic process and cell morphogenesis-cytoskeleton organization. The interaction of viral M protein with selected host proteins in mouse Neuro-2a cells infected with RABV was verified by super-resolution confocal microscopy. Molecular docking simulations also demonstrated the formation of RABV M complexes. However, further confirmation with co-immunoprecipitation was only successful for M-actin cytoplasmic 1 interaction. Our study revealed actin cytoplasmic 1 as a binding partner of M protein, which might have important role(s) in rabies pathogenesis.

Correlation between Osteoprotegerin Levels and Antiphospholipid Syndrome Parameters

OBJECTIVE

To identify the osteoprotegerin (OPG) correlates with antiphospholipid syndrome (APS) parameters.

METHODS

Our cohort included 40 patients with primary APS disease associated with systemic lupus erythematosus (SLE) (mean age, 43.7 years; 87% female). Data on cardiovascular risk factors and specific clinical events in APS were collected. Then we tested OPG and 10 criteria and noncriteria antiphospholipid antibodies (aPLs) on preserved specimens in all cases.

RESULTS

A total of 26 patients (65%) had high serum OPG levels. Patients with high OPG were mostly overweight. In patients with SLE, the OPG levels were associated with anti-double-stranded DNA (anti-dsDNA) and anti-Sm titers. However, we did not find significant correlations of the OPG with any of the 10 aPLs tested. Also, we found no relationship regarding venous APS events.

CONCLUSION

In APS, high OPG levels are not linked to serum aPL expression.

Salivary biomarkers of inflammation in systemic lupus erythematosus

Saliva is currently used as a reliable diagnostic fluid in a wide range of local and systemic diseases. However, the link between salivary diagnosis and the inflammatory process in autoimmune diseases has not yet been explored. The aim of our study is to assess possible correlations between salivary inflammatory markers and systemic lupus erythematosus (SLE). Patients fulfilling the Systemic Lupus International Collaborating Clinics (SLICC) diagnosis criteria were included. Salivary and serum levels of interleukin-6 (IL-6), leptin, monocyte chemoattractant protein-1 (MCP-1) and plasminogen activator inhibitor-1 (PAI-1) were determined using stochastic sensors. Serum leptin and IL-6 had significantly higher levels in SLE patients compared to non-SLE. Also, salivary IL-6 levels highly correlated with the serum IL-6 levels. A positive correlation was found between salivary and serum levels of IL-6, signaling salivary IL-6 as a reliable marker for assessing the inflammation process in SLE.

Associations of osteoprotegerin with coronary artery calcification among women with systemic lupus erythematosus and healthy controls

Objective We tested the hypothesis that higher circulating levels of osteoprotegerin (OPG) are related to higher levels of coronary artery calcification (CAC) among women with systemic lupus erythematosus (SLE) compared with healthy controls (HCs). Methods Among 611 women in two age- and race-matched SLE case-control studies, OPG was assayed in stored blood samples (HEARTS: plasma, n cases/controls = 122/124, and SOLVABLE: serum, n cases/controls = 185/180) and CAC was measured by electron beam computed tomography. Results In both studies, SLE patients had higher OPG and CAC levels than HCs. Higher OPG was associated with high CAC (>100 vs.100) among SLE, and with any CAC (>0 vs. 0) among HCs. Multivariable-adjusted OR (95% CI) for OPG tertile 3 vs. 1 was 3.58 (1.19, 10.76), p trend = 0.01 for SLE, and 2.28 (1.06, 4.89), p trend = 0.04 for HCs. Associations were attenuated when age-adjusted, but remained significant for HC women aged ≥ 40 and SLE women aged ≥ 50. ROC analyses identified 4.60 pmol/l as the optimal OPG cutpoint for predicting high CAC (>100) among SLE patients with sensitivity = 0.74 and specificity = 0.61, overall, but 0.92 and 0.52, respectively, for SLE patients aged ≥ 50. Conclusion Our cross-sectional results suggest that higher OPG levels are related to higher CAC levels among women with SLE vs. healthy controls.

Assessment of subclinical atherosclerosis in systemic lupus erythematosus: A systematic review and meta-analysis

OBJECTIVES

To determine whether subclinical atherosclerosis is increased in patients with systemic lupus erythematosus (SLE) compared to healthy individuals, using carotid intima-media thickness (CIMT), carotid plaque (CP) presence or flow-mediated dilatation (FMD).

METHODS

A systematic literature search was performed using MedLine, Embase and Cochrane databases. Two reviewers independently screened the articles to identify studies that compared the rates of atherosclerosis in SLE patients versus healthy controls. The results were pooled in a meta-analysis. Factors influencing the CIMT, CP or FMD results were collected.

RESULTS

Of the 203 articles initially identified, 68 were selected for the meta-analysis. Compared to healthy controls, SLE patients had a significantly increased CIMT (mean difference [MD] of 0.08mm, 95% CI [0.06-0.09], P<0.05), more CP (odds ratio 2.01, 95% CI [1.63-2.47], P<0.05) and decreased FMD (MD -3.96%, 95% CI [-5.37 to -2.54)], P<0.05). There was marked heterogeneity among the studies. However, the results of the meta-analysis that included only the CIMT per new international recommendations also showed an increased CIMT in SLE patients, but the heterogeneity was low (MD 0.04mm, 95% CI [0.02-0.06], P<0.05; I²=23%).

CONCLUSION

SLE patients exhibit increased subclinical atherosclerosis compared to healthy controls. CIMT is a promising measure for cardiovascular risk evaluations because non-invasive, non-radiation-based, reproducible. Thus, CIMT can be proposed as an alternative to the reliable CP evaluation and to FMD, which is influenced by independent factors such as smoking. Future studies should focus on reducing the heterogeneity of these measures using standardized procedures.

Serum osteoprotegrin (OPG) in subclinical atherosclerosis in systemic lupus erythematosus

Introduction Osteoprotegerin (OPG) is a member of the tumor necrosis factor (TNF) receptor family. It has recently been demonstrated that OPG is produced by a variety of tissues, including the cardiovascular system (heart, arteries, veins), lung, kidney, immune tissues, and bone. The OPG-RANKL signaling pathway is strongly related to vascular calcification. We determined the association of this biomarker with subclinical atherosclerosis in systemic lupus erythematous (SLE). Methods We measured OPG and markers of subclinical atherosclerosis (coronary artery calcium (CAC), carotid intima-media thickness (cIMT) carotid plaque) in 166 SLE patients (91% female, 64% Caucasian, 31% African American, 5% others, mean age 45 years). Subgroups of patients with different levels of OPG level were compared with respect to average levels of CAC, cIMT, and with respect to presence of carotid plaque. Age was adjusted for using multiple regression. Results OPG was highly correlated with age ( p < 0.0001). Individuals with higher levels of OPG tended to have higher measures of CAC, cIMT, and more carotid plaque. However, after adjustment for age, these associations, while still positive, were no longer statistically significant. Conclusion In our study much of the association observed was due to confounding by age, and after adjusting for age, our findings do not rule out the possibility of a null association.

Subclinical atherosclerosis in patients with systemic lupus erythematosus: A systemic review and meta-analysis

OBJECTIVE

Systemic lupus erythematosus (SLE) is associated with increased risk of cardiovascular disease. Carotid intima media thickness (CIMT) and carotid plaques are both frequently used to identify populations at higher cardiovascular risk. A systematic literature search and meta-analysis were performed to evaluate CIMT and carotid plaques difference between SLE patients and normal controls.

METHODS

The literatures comparing markers of cardiovascular risk (CIMT and prevalence of carotid plaques) in SLE and controls were systematically searched in PubMed, EMBASE and Cochrane databases. The overall mean CIMT difference and pooled odds ratio (OR) for the prevalence of carotid plaques between SLE patients and control groups were calculated by fixed-effects or random-effect model analysis. Meta-regression was performed to explore the potential influencing factors. Publication bias was examined by a funnel plot and Egger's test.

RESULTS

A total of 80 studies (6085 SLE patients and 4794 controls) were included in the final analysis, 71 studies with data on CIMT (4814 cases and 3773 controls) and 44 studies reporting on the prevalence of carotid plaques (4417 cases and 3528 controls). As compared to controls, SLE patients showed a higher CIMT (WMD: 0.07 mm; 95%CI: 0.06, 0.09; P<0.001), and an increased prevalence of carotid plaques (OR: 2.45; 95%CI: 2.02, 2.97; P<0.001). Meta-regression models showed that traditional cardiovascular risk factors (age, HDL and triglyceride of SLE patients) and lupus related risk factors (as expressed by duration, ESR, SLEDAI and steroids) had a significant influence on CIMT, steroids and triglyceride had significant influence on the prevalence of carotid plaques.

CONCLUSIONS

Our findings support the current evidence base for an increased cardiovascular burden in SLE patients and support the use of CIMT and carotid plaques in observational studies in SLE patients. The findings are of importance to design more specific prevention and treatment strategies.