Endothelial function in systemic lupus erythematosus: relationship to disease activity, cardiovascular risk factors, corticosteroid therapy, and coronary calcification

Acute Exposure to Simulated Nocturnal Train Noise Leads to Impaired Sleep Quality and Endothelial Dysfunction in Young Healthy Men and Women: A Sex-Specific Analysis

A series of human field studies demonstrated that simulated nocturnal traffic noise exposure impaired sleep quality and endothelial function, which could be significantly improved after intake of vitamin C in case of endothelial function. However, it remains unclear whether these changes follow a sex-specific pattern. Thus, we aimed to analyze the effect of simulated nocturnal train noise exposure on sleep quality, endothelial function and its associated changes after vitamin C intake, and other hemodynamic and biochemical parameters in young healthy men and women. We used data from a randomized crossover study, wherein 70 healthy volunteers (50% women) were each exposed to one control pattern (regular background noise) and two different train noise scenarios (30 or 60 train noise events per night, with average sound pressure levels of 52 and 54 dB(A), respectively, and peak sound level of 73-75 dB(A)) in their homes for three nights. After each night, participants visited the study center for the measurement of endothelial function as well as other hemodynamic and biochemical parameters. Sleep quality measured via self-report was significantly impaired after noise 30 and noise 60 nights in both men and women (p < 0.001 vs. control). Likewise, endothelial function measured by flow-mediated dilation (FMD) was significantly impaired after noise 30 and noise 60 nights in both men and women (p < 0.001 vs. control). While in women, vitamin C intake significantly improved FMD after both noise 30 and noise 60 study nights compared to control nights, no significant changes were observed in men. Exposure to simulated nocturnal train noise impairs sleep quality and endothelial function in both men and women, whereas a significant improvement of endothelial function after noise exposure and vitamin C intake could only be observed in women. These findings suggest for the first time that in men other mechanisms such as oxidative stress causing endothelial dysfunction may come into play.

Impact of Adipokines in Brachial Artery Flow-mediated Dilatation in Lupus Nephritis

Endothelial dysfunction is evident in systemic lupus erythematosus (SLE). Pro-inflammatory adipokines are involved in endothelial derangement and premature atherosclerosis, particularly in lupus nephritis (LN). This study aimed to investigate the impact of LN on endothelial function by estimating the serum levels of adiponectin, leptin, visfatin, and homeostatic model assessment-insulin resistance (HOMA-IR) and calculating the flow-mediated dilatation (FMD) of the brachial artery. This is a case-control study in which 190 systemic lupus patients who were fulfilling the American College of Rheumatology revised classification were enrolled. The patients were divided into 100 LN patients and 90 lupus non-nephritis patients. Demographic data, clinical parameters, and SLE activity were reported. Serum adiponectin, leptin, visfatin, and HOMA-IR were measured. The endothelial dysfunction was assessed by calculating the FMD of the brachial artery. The mean age of participants was 25.62 ± 5.81 years. Elevated levels of adiponectin, leptin, visfatin, and HOMA-IR were observed in LN cases (12.2 ± 0.3, 20.1 ± 0.5, 16.8 ± 0.1, and 12.0 ± 3.8, respectively) compared to non-nephritis cases (12.2 ± 0.3, 8.5 ± 0.5, 16.8 ± 0.5, and 9.0 ± 3.8, respectively) with a more reduced FMD percentage in LN cases with a statistical significance. Brachial artery FMD is negatively correlated with lipid profile, adipokines, and HOMA. Visfatin has better sensitivity (82.1%) and specificity (81%) with the area under a curve of 0.893, compared to other biomarkers. LN patients are characterized by impaired endothelial function. Elevated serum adiponectin, visfatin, and HOMA-IR were significantly correlated with poor FMD of the brachial artery. Visfatin has a better performance in detecting atherosclerosis.

Systemic Lupus Erythematosus and Endothelial Dysfunction: A Close Relationship

BACKGROUND

Accelerated atherosclerosis, responsible for premature cardiovascular disease, has been estimated to develop or progress in 10% of systemic lupus erythematosus (SLE) patients each year and to be 6-fold more frequent in SLE compared with the general population. The mechanisms underlying accelerated atherosclerosis in SLE are complex and involve classical and "non-classical" cardiovascular risk factors. Subclinical and disseminated atherosclerosis is associated with endothelial dysfunction and arterial stiffness.

OBJECTIVE

The aim of this review is to analyze the association between SLE and endothelial dysfunction.

RESULTS AND CONCLUSION

Different mechanisms have been proposed to explain the prevalence of endothelial dysfunction in SLE, which are briefly reported in this review: impaired clearance of apoptotic cells, oxidative stress markers, B cell activation with different circulating autoantibodies, different subtypes of T lymphocytes, cytokine cascade. Several studies and meta-analyses show a significant trend towards a prevalence of subclinical accelerated atherosclerosis in patients with SLE compared with healthy controls, since childhood. Based on general considerations, we suggest a multidisciplinary management to assess endothelial dysfunction at the diagnosis of the disease and to periodically search for and treat the traditional cardiovascular risk factors. Prospective studies are needed to confirm the benefits of this management.

A Pilot Study to Determine if Vitamin D Repletion Improves Endothelial Function in Lupus Patients

BACKGROUND

The endothelium is important not only in regulating vascular tone but also in modulating inflammation. Patients with systemic lupus erythematosus (SLE) have deficits in these endothelial functions. Vitamin D is a nuclear hormone that regulates vascular endothelial nitric oxide synthase activity and expression. Many SLE patients have insufficient levels of vitamin D. The effect of this hormone on vascular endothelial function in SLE patients is not known. This study was designed to determine the effect size of repleting vitamin D levels on endothelial function in patients with SLE and vitamin D deficiency.

METHODS

SLE patients with 25(OH) vitamin D (25(OH)D) levels <20 ng/mL were randomized to oral vitamin D3 (D3) doses that did or did not raise 25(OH)D levels to ≥32 ng/mL. Endothelial function was measured with flow-mediated dilation (FMD) before and after 16 weeks of vitamin D3 supplementation.

RESULTS

Half of those who achieved 25(OH)D levels of ≥32 ng/mL experienced increases in FMD, whereas none of those with continued low 25(OH)D levels did. Those with increases in FMD had significantly higher final 25(OH)D levels. Using the effect size from this study, future studies designed to test the effect of repleting 25(OH)D on FMD in vitamin D-deficient SLE patients will require 35 patients in each group.

CONCLUSIONS

These results suggest a potential role for vitamin D in SLE-related endothelial dysfunction and that an adaptive, multi-arm, treat-to-target, serum-level trial design may increase the efficiency and likelihood of success of such a study.

[Assessment of endothelial function in autoimmune diseases]

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to an increase in cardiovascular disease incidence. In addition to traditional cardiovascular risk factors, endothelial dysfunction is an important early event in the pathogenesis of atherosclerosis, contributing to plaque initiation and progression. Endothelial dysfunction is characterized by a shift of the actions of the endothelium toward reduced vasodilation, a proinflammatory and a proadhesive state, and prothrombic properties. Therefore, assessment of endothelial dysfunction targets this vascular phenotype using several biological markers as indicators of endothelial dysfunction. Measurements of soluble adhesion molecules (ICAM-1, VCAM-1, E-selectin), pro-thrombotic factors (thrombomodulin, von Willebrand factor, plasminogen activator inhibitor-1) and inflammatory cytokines are most often performed. Regarding the functional assessment of the endothelium, the flow-mediated dilatation of conduit arteries is a non-invasive method widely used in pathophysiological and interventional studies. In this review, we will briefly review the most relevant information upon endothelial dysfunction mechanisms and explorations. We will summarize the similarities and differences in the biological and functional assessments of the endothelium in different autoimmune diseases.

Stiffness parameters, intima-media thickness and early atherosclerosis in systemic lupus erythematosus patients

Detection of early carotid vascular disease in patients with systemic lupus erythematosus (SLE) is considered mandatory for evaluation of subclinical atherosclerosis (ATS), and various ultrasonographic (US) parameters have been proposed. In the present investigation, 33 SLE and 33 healthy age-matched females have been studied by colour-coded sonography of the common carotid artery, assessing intima-media thickness (IMT), vascular strain (VS), vascular distensibility (VD), vascular stiffness (VSf) and pressure-strain elastic modulus (PSEM) as possible markers of early ATS. Patients with SLE, despite equivalent exposure to “traditional” cardiovascular risk factors, presented a higher mean IMT of the common carotid artery than healthy subjects (0.7 ± 0.2 mm vs 0.5 ± 0.1 mm – P < 0.0001). Of the stiffness parameters, patients with lupus showed a mean VSf of 0.72 ± 0.38 vs 0.54 ± 0.14 in controls ( P < 0.0001) and a mean PSEM of 6.0 ± 2.8 Pa vs 3.0 ± 1.4 Pa in controls ( P < 0.0001). Mean VS and VD were significantly lower in patients with SLE than in healthy subjects ( P < 0.0001). Among individuals with IMT < 0.6 mm, patients with SLE presented more compromised stiffness parameters. IMT was shown to be a useful parameter in the evaluation of vascular damage, even in a “sub-clinical” phase, while stiffness parameters provide additional details regarding endothelial and vessel functional state. Combined evaluation may allow ATS to be detected in the early stages in patients with SLE.

N-terminal pro-brain natriuretic peptide in systemic lupus erythematosus: relationship with inflammation, augmentation index, and coronary calcification

OBJECTIVE

Cardiovascular mortality is increased in systemic lupus erythematosus (SLE). Increased plasma concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) are associated with cardiovascular morbidity and mortality in the general population. We examined the hypothesis that NT-proBNP concentrations are higher in patients with SLE, and are related to inflammation, augmentation index, coronary atherosclerosis, and cardiovascular risk factors.

METHODS

Serum concentrations of NT-proBNP were measured in 113 patients with SLE and in 80 control subjects. Coronary calcification and augmentation index were measured by electron beam computed tomography and noninvasive pulse wave analysis, respectively.

RESULTS

Patients with SLE had higher concentrations of NT-proBNP [median 38.6 (interquartile range 2.5-126.9) pg/ml] than controls [11.7 (1.6-47.9) pg/ml] (p = 0.002). Augmentation index was higher in patients with SLE [25.0% (20.5%-31.5%)] than controls [20.5% (12.0%-29.0%)] (p = 0.04). In patients with SLE, NT-proBNP concentrations were associated with disease damage (rho = 0.31, p < 0.001) and duration (rho = 0.21, p = 0.02) but not with disease activity, C-reactive protein, erythrocyte sedimentation rate, tumor necrosis factor-alpha, interleukin 6, coronary calcium score, or augmentation index (all p > or = 0.18).

CONCLUSION

Patients with SLE have increased concentrations of NT-proBNP, but this is not explained by atherosclerotic burden, augmentation index, or inflammatory state.

Cardiovascular risk scores and the presence of subclinical coronary artery atherosclerosis in women with systemic lupus erythematosus

The Framingham risk score is widely used to identify patients at increased cardiovascular risk, and women with systemic lupus erythematosus (SLE) have a marked increased prevalence of cardiovascular events. Thus, we examined the hypothesis that cardiovascular risk scores would identify women with SLE who had asymptomatic coronary atherosclerosis. Ninety-three women with SLE and 65 control subjects were studied. The Framingham score and a score for younger populations developed from the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study were compared in both groups. Coronary atherosclerosis was ascertained by electron beam computed tomography. There were no significant differences in the median (interquartile range) Framingham [5 (2-10) compared to 7 (0-10), P = 0.88] and PDAY [15 (14-18) compared to 16 (13-18), P = 0.99] scores in patients with SLE and controls, respectively. Coronary atherosclerosis was associated with higher Framingham [12 (3-15) compared to 4 (1-8), P = 0.008] and PDAY [17 (15-19 compared to 15 (12-18), P = 0.03)] scores in patients with SLE; however, 99% of patients were classified as low-risk with a 10-year predicted risk of 1% (<1-3%). Our data indicate that cardiovascular risk scores are not adequate for risk stratification in women with SLE. Measurement of coronary calcification may add information to identify asymptomatic women with lupus who might benefit from aggressive preventive measures.