Apolipoprotein B as an independent predictor of arterial stiffness in systemic lupus erythematosus patients

Arterial Stiffness as a Surrogate Marker of Cardiovascular Disease and Atherosclerosis in Patients with Arthritides and Connective Tissue Diseases: A Literature Review

The increased cardiovascular (CV) risk among patients with autoimmune rheumatic diseases, such as arthritides and connective tissue diseases, has been extensively documented. From a pathophysiological standpoint, systemic inflammation in the context of the disease can lead to endothelial dysfunction, accelerated atherosclerosis, and structural changes in vessel walls, which, in turn, are associated with exaggerated CV morbidity and mortality. In addition to these abnormalities, the increased prevalence of traditional CV risk factors, such as obesity, dyslipidemia, arterial hypertension, and impaired glucose metabolism, can further worsen the status of and overall prognosis for CV in rheumatic patients. However, data on appropriate CV screening methods for patients with systemic autoimmune diseases are scarce, and traditional algorithms may lead to an underestimation of the true CV risk. The reason for this is that these calculations were developed for the general population and thus do not take into account the effect of the inflammatory burden, as well as other chronic-disease-associated CV risk factors. In recent years, different research groups, including ours, have examined the value of different CV surrogate markers, including carotid sonography, carotid-femoral pulse wave velocity, and flow-mediated arterial dilation, in the assessment of CV risk in healthy and rheumatic populations. In particular, arterial stiffness has been thoroughly examined in a number of studies, showing high diagnostic and predictive value for the occurrence of CV events. To this end, the present narrative review showcases a series of studies examining aortic and peripheral arterial stiffness as surrogates of all-cause CV disease and atherosclerosis in patients with rheumatoid and psoriatic arthritis, as well as in systemic lupus erythematosus and systemic sclerosis. Moreover, we discuss the associations of arterial stiffness with clinical, laboratory, and disease-specific parameters.

Multi-Platform Omics Analysis Reveals Molecular Signatures for Pathogenesis and Activity of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with heterogeneous clinical manifestations and the pathogenesis of SLE is still unclear. Various omics results have been reported for SLE, but the molecular hallmarks of SLE, especially in patients with different disease activity, using an integrated multi-omics approach have not been fully investigated. Here, we collected blood samples from 10 healthy controls (HCs) and 40 SLE patients with different clinical activity including inactive (IA), low activity (LA), and high activity (HA). Using an integrative analysis of proteomic, metabolomic and lipidomic profiles, we report the multi-omics landscape for SLE. The molecular changes suggest that both the complement system and the inflammatory response were activated in SLEs and were associated with disease activity. Additionally, activation of the immunoglobulin mediated immune response were observed in the LA stage of the disease, however this immune response was suppressed slightly in the HA stage. Finally, an imbalance in lipid metabolism, especially in sphingolipid metabolism, accompanied with dysregulated apolipoproteins were observed to contribute to the disease activity of SLE. The multi-omics data presented in this study and the characterization of peripheral blood from SLE patients may thus help provide important clues regarding the pathogenesis of SLE.

Increased apolipoprotein-B:A1 ratio predicts cardiometabolic risk in patients with juvenile onset SLE

BACKGROUND

Cardiovascular disease is a leading cause of mortality in patients with juvenile-onset systemic lupus erythematosus (JSLE). Traditional factors for cardiovascular risk (CVR) prediction are less robust in younger patients. More reliable CVR biomarkers are needed for JSLE patient stratification and to identify therapeutic approaches to reduce cardiovascular morbidity and mortality in JSLE.

METHODS

Serum metabolomic analysis (including >200 lipoprotein measures) was performed on a discovery (n=31, median age 19) and validation (n=31, median age 19) cohort of JSLE patients. Data was analysed using cluster, receiver operating characteristic analysis and logistic regression. RNA-sequencing assessed gene expression in matched patient samples.

FINDINGS

Hierarchical clustering of lipoprotein measures identified and validated two unique JSLE groups. Group-1 had an atherogenic and Group-2 had an atheroprotective lipoprotien profile. Apolipoprotein(Apo)B:ApoA1 distinguished the two groups with high specificity (96.2%) and sensitivity (96.7%). JSLE patients with high ApoB:ApoA1 ratio had increased CD8+ T-cell frequencies and a CD8+ T-cell transcriptomic profile enriched in genes associated with atherogenic processes including interferon signaling. These metabolic and immune signatures overlapped statistically significantly with lipid biomarkers associated with sub-clinical atherosclerosis in adult SLE patients and with genes overexpressed in T-cells from human atherosclerotic plaque respectively. Finally, baseline ApoB:ApoA1 ratio correlated positively with SLE disease activity index (r=0.43, p=0.0009) and negatively with Lupus Low Disease Activity State (r=-0.43, p=0.0009) over 5-year follow-up.

INTERPRETATION

Multi-omic analysis identified high ApoB:ApoA1 as a potential biomarker of increased cardiometabolic risk and worse clinical outcomes in JSLE. ApoB:ApoA1 could help identify patients that require increased disease monitoring, lipid modification or lifestyle changes.

FUNDING

Lupus UK, The Rosetrees Trust, British Heart Foundation, UCL & Birkbeck MRC Doctoral Training Programme and Versus Arthritis.

Association Between sRAGE and Arterial Stiffness in Women with Systemic Lupus Erythematosus

BACKGROUND

sRAGE (soluble receptor for advanced glycation end products) is known to play a protective role in chronic inflammatory diseases, and has been found to be related to arterial stiffness in hypertensive or diabetic patients. This cross-sectional study was designed to study the potential association of sRAGE with arterial stiffness in systemic lupus erythematosus(SLE) patients.

METHODS

A total of 94 female SLE patients were enrolled. Brachial-ankle pulse wave velocity (baPWV) was measured by an automatic pulse wave analyzer. The patients were divided into two groups according to the baPWV values, those with values greater than 1400cm/s were placed in the high arterial stiffness group. Biochemical parameters were compared between the two groups. Linear and logistic regression analysis was used to observe the association between sRAGE and arterial stiffness in these patients.

RESULTS

Thirty-five patients were placed in the high arterial stiffness group in which sRAGE levels were lower (P<0.05). sRAGE levels were significantly related to baPWV(standardized β=1.18, P<0.01) by linear regression analysis. Multivariate logistic regression analysis showed that sRAGE, SLE duration, systolic blood pressure, and low-density lipoprotein cholesterol were independent predictors of arterial stiffness in these patients.

CONCLUSION

The results revealed that sRAGE was negatively associated with arterial stiffness in Chinese female SLE patients.

Inflammatory joint diseases and atherosclerosis: time to look beyond the 'lipid paradox'

PURPOSE OF REVIEW

Uncertainty persists about the contribution of lipids to the increased risk of cardiovascular disease (CVD) among rheumatoid arthritis and other inflammatory joint disease (IJD) patients. In reviewing recent research, we consider potential insights gained by quantifying lipoprotein particles directly, rather than by their lipid content.

RECENT FINDINGS

Although inflammation often decreases LDL cholesterol (LDL-C), and anti-inflammatory medications often increase LDL-C, both inflammation and anti-inflammatory medications can increase atherogenic Apolipoprotein B (ApoB)-containing lipoprotein particles, attenuated by statins. CVD risk factors, that is, smoking, obesity, ApoB, may increase years prior to IJD diagnosis. Increased risks of nonatherosclerotic myocardial and pulmonary disease, heart failure and mortality may be directly related to disease activity, inflammation, and possibly to HDL particles and function.

SUMMARY

For IJD patients, higher cumulative lifetime exposure to CVD risk factors accelerates atherosclerosis and subsequent CVD risk that is underestimated by current risk factor levels. CVD risk reduction in IJD requires aggressive and earlier reduction in CVD risk factors (ApoB lipoproteins, smoking, hypertension, diabetes, lack of physical activity), in addition to control of disease activity and inflammation. Lipid-lowering medications can attenuate anti-inflammatory medication-induced increases in ApoB and LDL-C, but can also reduce CVD risk due to cumulative lifetime exposure.

Foot and ankle characteristics in systemic lupus erythematosus: A systematic review and meta-analysis

OBJECTIVE

To determine characteristics of the foot and ankle in people with systemic lupus erythematosus (SLE).

METHODS

Medline, CINAHL, Sports-Discus, Scopus and Cochrane Library databases were searched up to January 2018. Studies reporting foot- and ankle-related outcomes in the following domains were included: vascular, neurological, musculoskeletal, cutaneous (skin and nail) or pain/function. The Quality Index tool was used to assess methodological quality. Where appropriate, odds ratio (OR) and mean difference meta-analyses were conducted for case-control studies; and pooled mean prevalence meta-analyses for studies assessing characteristics in SLE.

RESULTS

Forty-nine studies were included with mean (range) quality scores of 75% (38-100%). Twenty-three studies assessed vascular characteristics, followed by musculoskeletal (n = 16), neurological (n = 11), cutaneous (n = 5) and pain/function (n = 4). Foot and ankle characteristics in people with SLE included impaired vascular supply, abnormal nerve function, musculoskeletal pathology, skin and nail pathology, and pain and functional disability. Twenty-four studies were included in meta-analyses. Pooled OR for abnormal ankle brachial index was 3.08 for SLE compared with controls. Pooled mean difference in brachial-ankle pulse-wave velocity between SLE and controls was significant (161.39 cm/s, P = 0.004). Pooled prevalence was 0.54 for intermittent claudication, 0.50 for Raynaud's phenomenon, 0.28 for chilblains, 0.00 for gangrene, 0.30 for hallux valgus, 0.15 for onychomycosis, 0.76 for history of foot pain, and 0.36 for current foot pain.

CONCLUSION

People with SLE experience a wide range of foot and ankle manifestations. Published research highlights the impact of peripheral arterial disease, peripheral neuropathy, musculoskeletal deformity, skin and nail pathology and patient-reported foot pain and disability.

Lipid profile among girls with systemic lupus erythematosus

The aim of the study was to describe biomarkers of lipid metabolism associated with increased cardiovascular risk and their correlation with disease variables and markers of inflammation in adolescent females with systemic lupus erythematosus (SLE). This cross-sectional controlled study evaluated 33 adolescent females with juvenile SLE and 33 healthy controls. Anthropometric data, SLE disease activity index (SLEDAI), medications, proteinuria, ultra-sensitive C-reactive protein (us-CRP), lipid profile (total cholesterol, LDL-c, HDL-c and triglycerides), apolipoproteins A and B (Apo A-I and B), paraoxonase, and myeloperoxidase were evaluated. Median age of the patients and the median disease duration were 16.7 years and 54 months, respectively. SLEDAI scores above 4 were observed in 11 (33.3 %) patients. Moreover, 12 (36.4 %) patients were overweight, and 5 (15.2 %) had low height for age ratios. Dyslipidemia was observed in 13 (39.4 %) patients and in 7 (21.2 %) controls with a decrease in HDL-c concentrations in SLE patients even after adjustment for their nutritional status. In the group with SLE, us-CRP concentrations were inversely correlated with LDL-c/ApoB ratio (p = 0.031). After multivariate regression analysis, the SLE group showed lower concentration of Apo A-I and a decreased LDL-c/ApoB ratio. SLE adolescent females with low disease activity, with preserved kidney function and on low dose of corticosteroids, regardless of nutritional status and food intake, have proatherogenic lipid biomarkers, which may contribute to an increased atherosclerotic risk.

High-density lipopoprotein antioxidant capacity, subpopulation distribution and paraoxonase-1 activity in patients with systemic lupus erythematosus

Background

The causes of increased cardiovascular risk in systemic lupus erythematosus (SLE) are not understood thoroughly, although presence of traditional cardiovascular risk factors and disease-specific agents were also proposed. In this study, we investigated the quantitative changes in the lipid profile, as well as qualitative characteristics of high-density lipoprotein (HDL) and markers of inflammation and disease activity in SLE patients.

Methods

Lipoprotein levels were determined in 51 SLE patients and 49 healthy controls, matched in age and gender. HDL antioxidant capacity was determined spectrophotometrically with a cell-free method of hemin-induced low-density lipoprotein (LDL) oxidation. Polyacrylamide gel-electrophoresis was used for HDL subfraction analysis. Human paraoxonase-1 (PON1) activity, apolipoprotein A1 (ApoA1) and oxidized LDL concentrations, as well as interleukin-6, high-sensitivity C-reactive protein, serum amyloid A and monocyte chemotactic protein-1 levels were determined.

Results

HDL-cholesterol and ApoA1 concentrations decreased significantly in SLE subjects. Also, PON1 arylesterase activity (125.65 ± 26.87 vs. 148.35 ± 39.34 U/L, p = 0.001) and total HDL antioxidant capacity (165.82 ± 58.28 % vs. 217.71 ± 54.36 %, p < 0.001) were significantly reduced in patients compared to controls. Additionally, all HDL subfraction concentrations were significantly decreased in patients, while the levels of the examined inflammatory markers were significantly elevated in SLE subjects. The latter correlated positively with disease activity, and negatively with HDL concentration and total HDL antioxidant capacity, respectively. PON1 arylesterase activity and erythrocyte sedimentation rate were independent predictors of total HDL antioxidant capacity.

Conclusions

Induced by the systemic inflammation, altered composition and antioxidant activity may diminish the anti-atherogenic effect of HDL and therefore may contribute to the increased cardiovascular risk of SLE patients.