Patients with Rheumatoid Arthritis Show Altered Lipoprotein Profiles with Dysfunctional High-Density Lipoproteins that Can Exacerbate Inflammatory and Atherogenic Process

Association of HDL and LDL levels with osteoporosis in rheumatoid arthritis: a retrospective cohort study

OBJECTIVES

A correlation exists between lipids and osteoporosis (OP), as well as between lipids and rheumatoid arthritis (RA). However, lipids, the relationship between RA and OP is still unclear. This study mainly investigates the relationship between lipid levels and OP risk in RA patients.

METHODS

Retrospective collection of RA patient data from July 2017 to May 2022, encompassing baseline demographics, treatment regimens, laboratory results, and bone mineral density (BMD) measurements. Analyses, stratified by BMD subgroups, were conducted using propensity score matching (PSM) based on age, sex, and baseline duration, and binary logistic regression to examine the interplay between lipoprotein levels and other risk factors. The relationship between continuous variables and OP risk was assessed using restricted cubic spline (RCS), followed by a reanalysis of the correlation between varying lipoprotein levels and different factors, segmented according to RCS-determined cutoffs.

RESULTS

The study included 2673 RA patients. Binary logistic regression revealed significant associations between high-density lipoprotein (HDL), low-density lipoprotein (LDL), and RA-OP (p < 0.01). Specifically, HDL emerged as a protective factor against OP (OR = 0.40, 95% CI 0.250-0.629; p < 0.001), whereas LDL was identified as a risk factor (OR = 1.56, 95% CI 1.290-1.890; p < 0.001). Furthermore, HDL (RCS cutoff point 1.28 mmol/L) showed a negative, linear correlation with RA-related OP, while LDL (RCS cutoff point 2.63 mmol/L) demonstrated a positive, linear correlation.

CONCLUSIONS

The levels of HDL and LDL may be indicators of OP occurrence in RA patients.

Exploring Cardiovascular Risk Factors and Atherosclerosis in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease mainly affecting the peripheral diarthrodial joints symmetrically and also presenting many extra-articular manifestations. Morbidity and mortality in RA patients are higher compared to the general population. Cardiovascular (CV) disease is one of the most common causes of death in these patients. Classical or traditional risk factors for atherosclerosis development occur more frequently in RA patients compared to those without this condition. Studies have showed that RA patients often present comorbidities such as hypertension, dyslipidemia, diabetes mellitus and obesity. However, the high incidence of CV events occurring in RA patients is not explained by the presence of traditional risk factors. Systemic inflammation, as it is expressed with the presence of proinflammatory cytokines and increased acute phase reactants, may contribute to the development of premature atherosclerosis in these patients. In this review, we explore the risk factors for CV disease, the generation of dyslipidemia, the lipid paradox and the role of systemic inflammation in the atherosclerotic process in RA. We discuss also the role of early therapeutic intervention that suppresses inflammation which may have beneficial effects on CV disease in RA patients.

The association between remnant cholesterol and rheumatoid arthritis: insights from a large population study

OBJECTIVES

While lipid metabolism disorder is widely acknowledged as a contributing factor to inflammation, the association between remnant cholesterol (RC), which indicates lipid metabolism, and rheumatoid arthritis (RA) has not been investigated. Accordingly, this study evaluated whether RC is associated with RA disease events.

METHODS

Data were collected and specifically extracted from the National Health and Nutrition Examination Survey (NHANES) 1999-2008 database. The RC value was derived by subtracting the combined amount of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) from the total cholesterol (TC). The association between RC and RA was evaluated using multivariate regression analysis and subgroup analysis.

RESULTS

The study analyzed 7777 patients, of which 581 patients (7.47%) were diagnosed with RA. After accounting for different covariates, the multivariate logistic regression analysis revealed a notable correlation between increased RC levels and an increased likelihood of RA (odds ratio OR = 1.54; 95% confidence interval CI: 1.11-2.13; P = 0.0092). The interaction test did not yield statistically significant effects on this association. The linear correlation between RC and RA was observed within restricted cubic spline regression model limitations.

CONCLUSION

The results suggest that higher RC levels are associated with increased odds of RA, indicating that RC can serve as a novel and convenient index for forecasting the likelihood of RA in the United States. Additionally, these findings offer insights into early intervention strategies for susceptible populations at risk of developing RA.

Low circulatory levels of total cholesterol, HDL-C and LDL-C are associated with death of patients with sepsis and critical illness: systematic review, meta-analysis, and perspective of observational studies

BACKGROUND

Mechanistic studies have established a biological role of sterol metabolism in infection and immunity with clinical data linking deranged cholesterol metabolism during sepsis with poorer outcomes. In this systematic review we assess the relationship between biomarkers of cholesterol homeostasis and mortality in critical illness.

METHODS

We identified articles by searching a total of seven electronic databases from inception to October 2023. Prospective observational cohort studies included those subjects who had systemic cholesterol (Total Cholesterol (TC), HDL-C or LDL-C) levels assessed on the first day of ICU admission and short-term mortality recorded. Meta-analysis and meta-regression were used to evaluate overall mean differences in serum cholesterol levels between survivors and non-survivors. Study quality was assessed using the Newcastle-Ottawa Scale.

FINDINGS

From 6469 studies identified by searches, 24 studies with 2542 participants were included in meta-analysis. Non-survivors had distinctly lower HDL-C at ICU admission -7.06 mg/dL (95% CI -9.21 to -4.91, p < 0.0001) in comparison with survivors. Corresponding differences were also seen less robustly for TC -21.86 mg/dL (95% CI -31.23 to -12.49, p < 0.0001) and LDL-C -8.79 mg/dL (95% CI, -13.74 to -3.83, p = 0.0005).

INTERPRETATION

Systemic cholesterol levels (TC, HDL-C and LDL-C) on admission to critical care are inversely related to mortality. This finding is consistent with the notion that inflammatory and metabolic setpoints are coupled, such that the maladaptive-setpoint changes of cholesterol in critical illness are related to underlying inflammatory processes. We highlight the potential of HDL-biomarkers as early predictors of severity of illness and emphasise that future research should consider the metabolic and functional heterogeneity of HDLs.

FUNDING

EU-ERDF-Welsh Government Ser Cymru programme, BBSRC, and EU-FP7 ClouDx-i project (PG).

Dyslipidemia in rheumatoid arthritis: the possible mechanisms

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease, of which the leading cause of death is cardiovascular disease (CVD). The levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) in RA decrease especially under hyperinflammatory conditions. It is conflictive with the increased risk of CVD in RA, which is called "lipid paradox". The systemic inflammation may explain this apparent contradiction. The increased systemic proinflammatory cytokines in RA mainly include interleukin-6(IL-6)、interleukin-1(IL-1)and tumor necrosis factor alpha(TNF-α). The inflammation of RA cause changes in the subcomponents and structure of HDL particles, leading to a weakened anti-atherosclerosis function and promoting LDL oxidation and plaque formation. Dysfunctional HDL can further worsen the abnormalities of LDL metabolism, increasing the risk of cardiovascular disease. However, the specific mechanisms underlying lipid changes in RA and increased CVD risk remain unclear. Therefore, this article comprehensively integrates the latest existing literature to describe the unique lipid profile of RA, explore the mechanisms of lipid changes, and investigate the impact of lipid changes on cardiovascular disease.

Power doppler ultrasound signal predicts abnormal HDL function in patients with rheumatoid arthritis

Active rheumatoid arthritis (RA) is associated with increased cardiovascular risk and impaired function of high-density lipoprotein (HDL). Previous work suggests that HDL may become dysfunctional through oxidative modifications within the RA joint. The current work evaluates an association of synovial power doppler ultrasound signal (PDUS) with HDL function and structure. Two open-label clinical therapeutic studies using PDUS as a disease outcome measure were included in this analysis, including a 12-month trial of subcutaneous abatacept in 24 RA patients and a 6-month trial of IV tocilizumab in 46 RA patients. Laboratory assays included assessments of HDL function and structure, HDL and total cholesterol levels, and a cytokine/chemokine panel. Patients with the highest baseline PDUS scores in both clinical studies, had worse HDL function, including suppression of paraoxonase 1 (PON1) activity as well as lower HDL-C levels. Associations between other disease assessments (DAS28 and CDAI) and HDL function/structure were noted but were generally of lesser magnitude and consistency than PDUS across the HDL profile. Treatment with tocilizumab for 6 months was associated with increases in cholesterol levels and improvements in the HDL function profile, which correlated with greater decreases in PDUS scores. Similar trends were noted following treatment with abatacept for 3 months. Higher baseline PDUS scores identified patients with worse HDL function. This data supports previous work suggesting a direct association of joint inflammation with abnormal HDL function.

Lipid metabolism and rheumatoid arthritis

As a chronic progressive autoimmune disease, rheumatoid arthritis (RA) is characterized by mainly damaging the synovium of peripheral joints and causing joint destruction and early disability. RA is also associated with a high incidence rate and mortality of cardiovascular disease. Recently, the relationship between lipid metabolism and RA has gradually attracted attention. Plasma lipid changes in RA patients are often detected in clinical tests, the systemic inflammatory status and drug treatment of RA patients can interact with the metabolic level of the body. With the development of lipid metabolomics, the changes of lipid small molecules and potential metabolic pathways have been gradually discovered, which makes the lipid metabolism of RA patients or the systemic changes of lipid metabolism after treatment more and more comprehensive. This article reviews the lipid level of RA patients, as well as the relationship between inflammation, joint destruction, cardiovascular disease, and lipid level. In addition, this review describes the effect of anti-rheumatic drugs or dietary intervention on the lipid profile of RA patients to better understand RA.

Suppressed paraoxonase-1 activity associates with elevated oxylipins and the presence of small airways disease in patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA)-associated lung disease (LD) associates with significantly increased morbidity and mortality. Although oxidative stress plays an important role in the inflammatory responses in other forms of lung disease, minimal work has evaluated its role in RA-LD. The current work examines the relationship between the anti-oxidant HDL-associated enzyme paraoxonase-1 (PON1), the PON1 Q192R polymorphism, and a targeted oxylipin panel with RA-LD.

METHODS

This study was conducted as a retrospective chart review of a longitudinal single-center cohort of 250 RA patients. CT scans of the chest were reviewed by the interpreting radiologist and classified as small airways disease (SAD), interstitial lung disease (ILD), and bronchiectasis. PON1 activity was measured by its lactonase, arylesterase, and paraoxonase functions. The PON1 Q192R polymorphism and a targeted lipidomics panel were performed as previously reported.

RESULTS

43.2% of the 250 RA patient cohort (n = 108) had available CT scans, including 48 patients (44.4%) with SAD, 27 patients (25.0%) with bronchiectasis, and 16 patients (14.8%) with ILD. Patients with SAD had significantly lower baseline PON1 activity by its arylesterase, and lactonase functions, as well as higher 15-HETE, LTB4, and PGE2 levels compared to those without SAD. These predictors of SAD remained significant after multivariate analysis including known risk factors for RA-LD. Suppressed PON1 activity also correlated with higher levels of 15-HETE and 12-HETE.

CONCLUSION

In a single-center RA cohort, suppressed baseline PON1 activity and elevation in the oxylipins 15-HETE, LTB4, and PGE2 predicted the presence of RA-SAD in longitudinal follow-up. Key Points • Small airways disease (SAD) was present in 44.4% of this rheumatoid arthritis (RA) cohort. • Patients with SAD had significantly lower baseline PON1 activity, as well as higher levels of the oxylipins 15-HETE, LTB4, and PGE2 levels compared to those without SAD. • Further work is warranted to confirm these findings and further define the role of PON1 and lipid oxidation in RA lung disease.

Congruence and Complementarity of Differential Mobility Spectrometry and NMR Spectroscopy for Plasma Lipidomics

The lipid composition of lipoprotein particles is determinative of their respective formation and function. In turn, the combination and correlation of nuclear magnetic resonance (NMR)-based lipoprotein measurements with mass spectrometry (MS)-based lipidomics is an appealing technological combination for a better understanding of lipid metabolism in health and disease. Here, we developed a combined workflow for subsequent NMR- and MS-based analysis on single sample aliquots of human plasma. We evaluated the quantitative agreement of the two platforms for lipid quantification and benchmarked our combined workflow. We investigated the congruence and complementarity between the platforms in order to facilitate a better understanding of patho-physiological lipoprotein and lipid alterations. We evaluated the correlation and agreement between the platforms. Next, we compared lipid class concentrations between healthy controls and rheumatoid arthritis patient samples to investigate the consensus among the platforms on differentiating the two groups. Finally, we performed correlation analysis between all measured lipoprotein particles and lipid species. We found excellent agreement and correlation (r > 0.8) between the platforms and their respective diagnostic performance. Additionally, we generated correlation maps detailing lipoprotein/lipid interactions and describe disease-relevant correlations.

Disease-modifying anti-rheumatic drugs improve the cardiovascular profile in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting about 0. 5–1% of the adult population and manifesting as persistent synovitis, systemic inflammation and production of autoantibodies. Patients affected by RA not only experience chronic disease progression, but are also burdened by a 1.5-fold increased cardiovascular (CV) risk, which is comparable to the risk experienced by patients with type 2 diabetes mellitus. RA patients also have a higher incidence and prevalence of coronary artery disease (CAD). Although RA patients frequently present traditional CV risk factors such as insulin resistance and active smoking, previous studies have clarified the pivotal role of chronic inflammation–driven by proinflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha)–in accelerating the process of atherosclerosis and impairing the coagulation system. Over the last years, a number of studies have shown that disease-modifying anti-rheumatic drugs (DMARDs) reducing the inflammatory state in general improve the CV risk, however some drugs may carry some apparent negative effects. Thus, RA is a model of disease in which targeting inflammation may counteract the progression of atherosclerosis and reduce CV risk. Clinical and experimental evidence indicates that the management of RA patients should be tailored based on the positive and negative effects of DMARDs on CV risk together with the individual traditional CV risk profile. The identification of genetic, biochemical and clinical biomarkers, predictive of evolution and response to treatment, will be the next challenge for a precision approach to reduce the burden of the disease.

Alterations of HDL's to piHDL's Proteome in Patients with Chronic Inflammatory Diseases, and HDL-Targeted Therapies

Chronic inflammatory diseases, such as rheumatoid arthritis, steatohepatitis, periodontitis, chronic kidney disease, and others are associated with an increased risk of atherosclerotic cardiovascular disease, which persists even after accounting for traditional cardiac risk factors. The common factor linking these diseases to accelerated atherosclerosis is chronic systemic low-grade inflammation triggering changes in lipoprotein structure and metabolism. HDL, an independent marker of cardiovascular risk, is a lipoprotein particle with numerous important anti-atherogenic properties. Besides the essential role in reverse cholesterol transport, HDL possesses antioxidative, anti-inflammatory, antiapoptotic, and antithrombotic properties. Inflammation and inflammation-associated pathologies can cause modifications in HDL's proteome and lipidome, transforming HDL from atheroprotective into a pro-atherosclerotic lipoprotein. Therefore, a simple increase in HDL concentration in patients with inflammatory diseases has not led to the desired anti-atherogenic outcome. In this review, the functions of individual protein components of HDL, rendering them either anti-inflammatory or pro-inflammatory are described in detail. Alterations of HDL proteome (such as replacing atheroprotective proteins by pro-inflammatory proteins, or posttranslational modifications) in patients with chronic inflammatory diseases and their impact on cardiovascular health are discussed. Finally, molecular, and clinical aspects of HDL-targeted therapies, including those used in therapeutical practice, drugs in clinical trials, and experimental drugs are comprehensively summarised.

Anti-Carbamylated Protein Antibodies, Tumour Necrosis Factor Alpha and Insulin Resistance in Egyptian Patients With Rheumatoid Arthritis and Systemic Lupus Erythematosus

BACKGROUND

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are autoimmune diseases. Premature atherosclerosis and cardiovascular diseases are two of the most important complications of these diseases. Anti-carbamylated protein antibody (Anti-carP Ab) is one of the antibodies which was studied in RA and SLE. In our study, we studied the relation between anti-carP Ab, disease activity and insulin resistance in RA and SLE patients.

METHODS

90Patients with SLE and RA were enrolled and subjected to history taking, clinical examination and assessment of disease activity using SLE disease activity index 2000 (SLEDAI-2K) scoring for SLE patients and disease activity score 28 (DAS28-ESR) for RA patients. Samples were examined for complete blood count (CBC), creatinine, inflammatory markers, Tumour necrosis factor alpha (TNF alpha), fasting insulin, fasting blood sugar (FBS), lipid profile and anti-carPAb. HOMA-IR (homeostasis model assessment for insulin resistance) was calculated.

RESULTS

Patients with RA and SLE showed higher levels of anti-carPAb in comparison with healthy subjects (8.25ng/ml for RA, 7ng/ml for SLE and 0.6ng/ml for healthy subjects with p value <0.001). There was a positive correlation between anti-carPAb and disease activity of RA (p value <0.001) and a positive correlation between anti-carPAb and TNF alpha in RA. In SLE, there was no correlation of anti-carP Ab with disease activity while, HOMA-IR showed a positive correlation with nephritis (p value 0.04).

CONCLUSION

Anti-carP antibody is a marker of disease activity in RA patients and has high specificity for both RA and SLE detection.

Human Serum Amyloid a Impaired Structural Stability of High-Density Lipoproteins (HDL) and Apolipoprotein (Apo) A-I and Exacerbated Glycation Susceptibility of ApoA-I and HDL

Human serum amyloid A (SAA) is an exchangeable apolipoprotein (apo) in high-density lipoprotein (HDL) that influences HDL quality and functionality, particularly in the acute phase of inflammation. On the other hand, the structural and functional correlations of HDL containing SAA and apoA-I have not been reported. The current study was designed to compare the change in HDL quality with increasing SAA content in the lipid-free and lipid-bound states in reconstituted HDL (rHDL). The expressed recombinant human SAA1 (13 kDa) was purified to at least 98% and characterized in the lipid-free and lipid-bound states with apoA-I. The dimyristoyl phosphatidylcholine (DMPC) binding ability of apoA-I was impaired severely by the addition of SAA, while SAA alone could not bind with DMPC. The recombinant human SAA1 was incorporated into the rHDL (molar ratio 95:5:1, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC): cholesterol: apoA-I) with various apoA-I:SAA molar ratios from 1:0 to 1:0.5, 1:1 and 1:2. With increasing SAA1 content, the rHDL particle size was reduced from 98 Å to 93 Å, and the α-helicity of apoA-I:SAA was decreased from 73% to 40% for (1:0) and (1:2), respectively. The wavelength maximum fluorescence (WMF) of tryptophan in rHDL was red-shifted from 339 nm to 345 nm for (1:0) and (1:2) of apoA-I:SAA, respectively, indicating that the addition of SAA to rHDL destabilized the secondary structure of apoA-I. Upon denaturation by urea treatment from 0 M to 8 M, SAA showed only a 3 nm red-shift in WMF, while apoA-I showed a 16 nm red-shift in WMF, indicating that SAA is resistant to denaturation and apoA-I had higher conformational flexibility than SAA. The glycation reaction of apoA-I in the presence of fructose was accelerated up to 1.8-fold by adding SAA in a dose-dependent manner than that of apoA-I alone. In conclusion, the incorporation of SAA in rHDL impaired the structural stability of apoA-I and exacerbated glycation of HDL and apoA-I.

Sex-Specific Associations Between Serum Lipids, Antinuclear Antibodies, and Statin Use in National Health and Nutrition Examination Surveys 1999-2004

Lipid metabolism contributes to the regulation of leukocyte activity and immune responses, and may serve as a therapeutic target in the pathophysiology and clinical management of autoimmune disorders. In addition to lipid-lowering properties, statins have been shown to exert anti-inflammatory and immunomodulatory effects within the context of autoimmunity. Importantly, autoimmune incidence and lipid markers differ between men and women, suggesting that the relationship between lipid metabolism and immune function may vary by sex. Therefore, we investigated whether a predictive, sex-specific relationship exists between serum lipids, statin use, and antinuclear antibodies (ANA)—a routine clinical marker of autoimmunity and immune dysfunction—in U.S. men and women (>20 years old; n = 1,526) from the National Health and Nutrition Examination Survey (NHANES) 1999–2004. Within this population, a greater proportion of women were positive for ANA (ANA+) and had higher ANA titers, as compared to men. While we did not observe statistical differences in average total cholesterol, LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), or triglyceride levels in ANA positive (ANA+) vs. ANA negative (ANA–) men or women, we observed that a greater proportion of ANA+ women had high total cholesterol levels (>240 mg/dL) when compared to ANA+ men (13.0 vs. 9.0%), and that a greater percentage of ANA+ women had low HDL-C as compared to ANA+ men (29.2 vs. 19.6%). However, in logistic regression models, total cholesterol, LDL-C, and HDL-C levels were not able to predict ANA status, whereas elevated serum triglycerides (150 to < 200 mg/dL) were significantly less likely to be ANA+ vs. ANA– (OR 0.33; 95% CI 0.11–0.92) in men only. Interestingly, women who reported taking statins have significantly lower odds of being ANA+ (OR 0.25; 95% CI 0.09–0.76), whereas no significant association between statin use and ANA status was observed in men. Together, our findings provide novel insight into the relationship between lipid metabolism and autoimmunity by elucidating the limited, albeit sex-specific utility of routine clinical serum lipid levels to predict ANA status at the population level, while further identifying a sex-specific and protective role for statins in predicting ANA status in women.

The Current Status of Research on High-Density Lipoproteins (HDL): A Paradigm Shift from HDL Quantity to HDL Quality and HDL Functionality

The quantity of high-density lipoproteins (HDL) is represented as the serum HDL-C concentration (mg/dL), while the HDL quality manifests as the diverse features of protein and lipid content, extent of oxidation, and extent of glycation. The HDL functionality represents several performance metrics of HDL, such as antioxidant, anti-inflammatory, and cholesterol efflux activities. The quantity and quality of HDL can change during one's lifetime, depending on infection, disease, and lifestyle, such as dietary habits, exercise, and smoking. The quantity of HDL can change according to age and gender, such as puberty, middle-aged symptoms, climacteric, and the menopause. HDL-C can decrease during disease states, such as acute infection, chronic inflammation, and autoimmune disease, while it can be increased by regular aerobic exercise and healthy food consumption. Generally, high HDL-C at the normal level is associated with good HDL quality and functionality. Nevertheless, high HDL quantity is not always accompanied by good HDL quality or functionality. The HDL quality concerns the morphology of the HDL, such as particle size, shape, and number. The HDL quality also depends on the composition of the HDL, such as apolipoproteins (apoA-I, apoA-II, apoC-III, serum amyloid A, and α-synuclein), cholesterol, and triglyceride. The HDL quality is also associated with the extent of HDL modification, such as glycation and oxidation, resulting in the multimerization of apoA-I, and the aggregation leads to amyloidogenesis. The HDL quality frequently determines the HDL functionality, which depends on the attached antioxidant enzyme activity, such as the paraoxonase and cholesterol efflux activity. Conventional HDL functionality is regression, the removal of cholesterol from atherosclerotic lesions, and the removal of oxidized species in low-density lipoproteins (LDL). Recently, HDL functionality was reported to expand the removal of β-amyloid plaque and inhibit α-synuclein aggregation in the brain to attenuate Alzheimer's disease and Parkinson's disease, respectively. More recently, HDL functionality has been associated with the susceptibility and recovery ability of coronavirus disease 2019 (COVID-19) by inhibiting the activity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The appearance of dysfunctional HDL is frequently associated with many acute infectious diseases and chronic aging-related diseases. An HDL can be a suitable biomarker to diagnose many diseases and their progression by monitoring the changes in its quantity and quality in terms of the antioxidant and anti-inflammatory abilities. An HDL can be a protein drug used for the removal of plaque and as a delivery vehicle for non-soluble drugs and genes. A dysfunctional HDL has poor HDL quality, such as a lower apoA-I content, lower antioxidant ability, smaller size, and ambiguous shape. The current review analyzes the recent advances in HDL quantity, quality, and functionality, depending on the health and disease state during one's lifetime.

Treatment of Cardiovascular Disease in Rheumatoid Arthritis: A Complex Challenge with Increased Atherosclerotic Risk

Rheumatoid arthritis (RA) carries significant risk for atherosclerotic cardiovascular disease (ASCVD). Traditional ASCVD risk factors fail to account for this accelerated atherosclerosis. Shared inflammatory pathways are fundamental in the pathogenesis of both diseases. Considering the impact of RA in increasing cardiovascular morbidity and mortality, the characterization of therapies encompassing both RA and ASCVD management merit high priority. Despite little progress, several drugs discussed here promote remission and or lower rheumatoid disease activity while simultaneously conferring some level of atheroprotection. Methotrexate, a widely used disease-modifying drug used in RA, is associated with significant reduction in cardiovascular adverse events. MTX promotes cholesterol efflux from macrophages, upregulates free radical scavenging and improves endothelial function. Likewise, the sulfonamide drug sulfasalazine positively impacts the lipid profile by increasing HDL-C, and its use in RA has been correlated with reduced risk of myocardial infraction. In the biologic class, inhibitors of TNF-α and IL-6 contribute to improvements in endothelial function and promote anti-atherogenic properties of HDL-C, respectively. The immunosuppressant hydroxychloroquine positively affects insulin sensitization and the lipid profile. While no individual therapy has elicited optimal atheroprotection, further investigation of combination therapies are ongoing.

Anti-Carbamylated Protein Antibodies, Tumour Necrosis Factor Alpha and Insulin Resistance in Egyptian Patients With Rheumatoid Arthritis and Systemic Lupus Erythematosus

BACKGROUND

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are autoimmune diseases. Premature atherosclerosis and cardiovascular diseases are two of the most important complications of these diseases. Anti-carbamylated protein antibody (Anti-carP Ab) is one of the antibodies which was studied in RA and SLE. In our study, we studied the relation between anti-carP Ab, disease activity and insulin resistance in RA and SLE patients.

METHODS

90Patients with SLE and RA were enrolled and subjected to history taking, clinical examination and assessment of disease activity using SLE disease activity index 2000 (SLEDAI-2K) scoring for SLE patients and disease activity score 28 (DAS28-ESR) for RA patients. Samples were examined for complete blood count (CBC), creatinine, inflammatory markers, Tumour necrosis factor alpha (TNF alpha), fasting insulin, fasting blood sugar (FBS), lipid profile and anti-carPAb. HOMA-IR (homeostasis model assessment for insulin resistance) was calculated.

RESULTS

Patients with RA and SLE showed higher levels of anti-carPAb in comparison with healthy subjects (8.25ng/ml for RA, 7ng/ml for SLE and 0.6ng/ml for healthy subjects with p value <0.001). There was a positive correlation between anti-carPAb and disease activity of RA (p value <0.001) and a positive correlation between anti-carPAb and TNF alpha in RA. In SLE, there was no correlation of anti-carP Ab with disease activity while, HOMA-IR showed a positive correlation with nephritis (p value 0.04).

CONCLUSION

Anti-carP antibody is a marker of disease activity in RA patients and has high specificity for both RA and SLE detection.

Evaluation of dysfunctional high-density lipoprotein levels with myeloperoxidase/paraoxonase-1 ratio in rheumatoid arthritis

BACKGROUND

The aim of this study is to evaluate dysfunctional high-density lipoprotein cholesterol (HDL) by measuring myeloperoxidase (MPO)/paraoxonase 1 (PON1) ratio in patients with rheumatoid arthritis (RA) and to investigate the relationship between dysfunctional HDL and cardiovascular disease (CVD) in RA patients.

METHODS

Sixty-seven healthy individuals and 130 RA patients were included in the study. Routine lipid panels (triglyceride (TG), low-density lipoprotein cholesterol (LDL), HDL, total cholesterol (TC), PON1 and MPO levels were measured. Disease activity scores-28 (DAS28) of RA patients were calculated. Cardiological examination records of the patients were assessed to detect patients who also have CVD.

RESULTS

There were no significant differences between RA and control groups in routine lipid profiles (P > .05 for all). MPO/PON1 ratios were significantly elevated in the RA group compared with the control group (P < .001). MPO/PON1 ratios were higher in RA patients with CVD history compared with those without CVD (P < .05). MPO/PON1 ratios were correlated with DAS28 scores (rho: 0.357, P < .001).

CONCLUSION

HDL dysfunction determined by the MPO/PON1 ratio may be associated with the pathophysiology of increased CVD in RA. Thus, evaluating dysfunctional HDL levels by measuring the MPO/PON1 ratio in RA patients may allow more detailed patient follow-up, as well as the reduction of CVD events in RA patients with therapeutic agents aiming to increase the functional properties of HDL by decreasing this ratio.

Disruptive Selection of Human Immunostimulatory and Immunosuppressive Genes Both Provokes and Prevents Rheumatoid Arthritis, Respectively, as a Self-Domestication Syndrome

Using our previously published Web service SNP_TATA_Comparator, we conducted a genome-wide study of single-nucleotide polymorphisms (SNPs) within core promoters of 68 human rheumatoid arthritis (RA)-related genes. Using 603 SNPs within 25 genes clinically associated with RA-comorbid disorders, we predicted 84 and 70 candidate SNP markers for overexpression and underexpression of these genes, respectively, among which 58 and 96 candidate SNP markers, respectively, can relieve and worsen RA as if there is a neutral drift toward susceptibility to RA. Similarly, we predicted natural selection toward susceptibility to RA for 8 immunostimulatory genes (e.g., IL9R) and 10 genes most often associated with RA (e.g., NPY). On the contrary, using 25 immunosuppressive genes, we predicted 70 and 109 candidate SNP markers aggravating and relieving RA, respectively (e.g., IL1R2 and TGFB2), suggesting that natural selection can simultaneously additionally yield resistance to RA. We concluded that disruptive natural selection of human immunostimulatory and immunosuppressive genes is concurrently elevating and reducing the risk of RA, respectively. So, we hypothesize that RA in human could be a self-domestication syndrome referring to evolution patterns in domestic animals. We tested this hypothesis by means of public RNA-Seq data on 1740 differentially expressed genes (DEGs) of pets vs. wild animals (e.g., dogs vs. wolves). The number of DEGs in the domestic animals corresponding to worsened RA condition in humans was significantly larger than that in the related wild animals (10 vs. 3). Moreover, much less DEGs in the domestic animals were accordant to relieved RA condition in humans than those in the wild animals (1 vs. 8 genes). This indicates that the anthropogenic environment, in contrast to a natural one, affects gene expression across the whole genome (e.g., immunostimulatory and immunosuppressive genes) in a manner that likely contributes to RA. The difference in gene numbers is statistically significant as confirmed by binomial distribution (p < 0.01), Pearson's χ² (p < 0.01), and Fisher's exact test (p < 0.05). This allows us to propose RA as a candidate symptom within a self-domestication syndrome. Such syndrome might be considered as a human's payment with health for the benefits received during evolution.

The role of abnormalities of lipoproteins and HDL functionality in small fibre dysfunction in people with severe obesity

Obesity and associated dyslipidemia may contribute to increased cardiovascular disease. Obesity has also been associated with neuropathy. We have investigated presence of peripheral nerve damage in patients with severe obesity without type 2 diabetes and the status of metabolic syndrome and lipoprotein abnormalities. 47participants with severe obesity and 30 age-matched healthy controls underwent detailed phenotyping of neuropathy and an assessment of lipoproteins and HDL-functionality. Participants with severe obesity had a higher neuropathy symptom profile, lower sural and peroneal nerve amplitudes, abnormal thermal thresholds, heart rate variability with deep breathing and corneal nerve parameters compared to healthy controls. Circulating apolipoprotein A1 (P = 0.009), HDL cholesterol (HDL-C) (P < 0.0001), cholesterol efflux (P = 0.002) and paroxonase-1 (PON-1) activity (P < 0.0001) were lower, and serum amyloid A (SAA) (P < 0.0001) was higher in participants with obesity compared to controls. Obese participants with small nerve fibre damage had higher serum triglycerides (P = 0.02), lower PON-1 activity (P = 0.002) and higher prevalence of metabolic syndrome (58% vs. 23%, P = 0.02) compared to those without. However, HDL-C (P = 0.8), cholesterol efflux (P = 0.08), apoA1 (P = 0.8) and SAA (P = 0.8) did not differ significantly between obese participants with and without small nerve fibre damage. Small nerve fibre damage occurs in people with severe obesity. Patients with obesity have deranged lipoproteins and compromised HDL functionality compared to controls. Obese patients with evidence of small nerve fibre damage, compared to those without, had significantly higher serum triglycerides, lower PON-1 activity and a higher prevalence of metabolic syndrome.

HDL in Immune-Inflammatory Responses: Implications beyond Cardiovascular Diseases

High density lipoproteins (HDL) are heterogeneous particles composed by a vast array of proteins and lipids, mostly recognized for their cardiovascular (CV) protective effects. However, evidences from basic to clinical research have contributed to depict a role of HDL in the modulation of immune-inflammatory response thus paving the road to investigate their involvement in other diseases beyond those related to the CV system. HDL-C levels and HDL composition are indeed altered in patients with autoimmune diseases and usually associated to disease severity. At molecular levels, HDL have been shown to modulate the anti-inflammatory potential of endothelial cells and, by controlling the amount of cellular cholesterol, to interfere with the signaling through plasma membrane lipid rafts in immune cells. These findings, coupled to observations acquired from subjects carrying mutations in genes related to HDL system, have helped to elucidate the contribution of HDL beyond cholesterol efflux thus posing HDL-based therapies as a compelling interventional approach to limit the inflammatory burden of immune-inflammatory diseases.

Paraoxonase 1 Phenotype and Protein N-Homocysteinylation in Patients with Rheumatoid Arthritis: Implications for Cardiovascular Disease

Paraoxonase 1 (PON1) is the high density lipoprotein-associated esterase which inhibits the development of atherosclerosis by metabolizing lipid peroxidation products as well as hydrolyzing proatherogenic metabolite of homocysteine (Hcy), Hcy thiolactone, which otherwise reacts with lysine groups of proteins, thus forming N-Hcy-protein in a process referred to as protein N-homocysteinylation. Rheumatoid arthritis (RA) is the chronic inflammatory autoimmune disease associated with increased risk of cardiovascular complications, but the underlying mechanisms are incompletely understood. We examined PON1 status and N-homocysteinylation of serum proteins in patients with RA. Blood was collected from 74 RA patients and 70 control subjects. PON1 activity was measured toward synthetic (paraoxon, phenyl acetate) and natural (Hcy thiolactone) substrates. PON1 protein concentration was measured by ELISA. Total Hcy as well as N-Hcy-protein were measured in serum as well. PON1 activity toward Hcy thiolactone was lower in RA patients than in control subjects which was accompanied by increased concentration of N-Hcy-protein despite normal total Hcy concentration. PON1 protein concentration was unchanged in the RA group, but the specific enzyme activity was reduced. When RA patients were categorized according to the DAS28-ESR score, PON1 concentration and enzymatic activity were lower whereas N-Hcy-protein was higher in those with high disease activity. PON1 activity and Hcy thiolactone were correlated with DAS28-ESR score and myeloperoxidase concentration. In conclusion, RA is associated with deficiency of PON1 activity and increased protein N-homocyseinylation which may contribute to accelerated development of cardiovascular diseases.

Effects of disease activity on lipoprotein levels in patients with early arthritis: can oxidized LDL cholesterol explain the lipid paradox theory?

Background

An increased risk of cardiovascular (CV) complications has been described in patients with rheumatoid arthritis (RA). It is the result of the combined effect of classic CV risk factors and others that are specific to the disease.

Methods

We assessed data from 448 early arthritis (EA) patients: 79% women, age (median [p25-p75]) at onset: 55 [44–67] years and disease duration at study entry 5 [3–8] months; and 72% fulfilled the 1987 RA criteria at 2 years of follow-up. Rheumatoid factor was positive in 54% of patients and anti-citrullinated peptide antibodies in 50%. The follow-up of patients ranged from 2 to 5 years with more than 1400 visits with lipoprotein measurements available (mean 2.5 visits/patient). Demographic- and disease-related variables were systematically recorded. Total cholesterol (TC), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) levels were obtained from routine laboratory tests. Oxidized-LDL (oxLDL-C) levels were assessed using a commercial ELISA kit. We fitted population-averaged models nested by patient and visit to determine the effect of independent variables on serum levels of TC, its fractions, and oxLDL-C.

Results

After adjustment for several confounders, high-disease activity was significantly associated with decreased TC, HDL-C, and LDL-C levels and increased oxLDL-C levels. Standardized coefficients showed that the effect of disease activity was greater on oxLDL-C and HDL-C. Interestingly, we observed that those patients with lower levels of LDL-C showed higher oxLDL-C/LDL-C ratios.

Conclusions

High-disease activity in EA patients results in changes in the HDL-C and oxLDL-C levels, which in turn may contribute to the increased risk of CV disease observed in these patients.

Immunotherapy for the rheumatoid arthritis-associated coronary artery disease: promise and future

Objective:

To review the latest progress on the pathogenic mechanism and management of rheumatoid arthritis (RA)-associated coronary artery disease (CAD), and propose advice on future management optimization as well as prospects for research and development of new therapeutic regimen.

Data sources:

This study was based on data obtained from PubMed up to May 2019 using various search terms and their combinations, including coronary artery disease, myocardial ischemia, cardiovascular diseases, RA, rheumatic diseases, treatment, therapy, strategies, immunotherapy, inflammation, and anti-inflammation.

Study selection:

All retrieved literature was scrutinized, most relevant articles about the pathogenic mechanism and clinical management, especially anti-inflammatory therapy of RA-associated CAD were reviewed.

Results:

RA is an immune-mediated chronic inflammatory disease which has a great social disease burden. In addition to typical arthritic manifestations, RA also affects extra-articular tissues and organs, within which the involvement of the cardiovascular system, especially incorporating CAD, is the leading cause of death for patients with RA. Recently, numerous basic and clinical studies have been carried out on the mechanism of CAD development and progression under the inflammatory cascade of RA. The effect of traditional RA drugs on CAD risk management has been gradually clarified, and more emerging biologic agents are being explored and studied, which have also achieved satisfactory outcomes. Furthermore, with the success of the CANTOS clinical trial, novel anti-inflammatory therapy for the prevention of cardiovascular disease is believed to have a broad prospect.

Conclusions:

RA is an independent risk factor for CAD, which mainly results from the underlying inflammatory cascade; therefore, anti-inflammatory therapy, especially the emerging novel biologic drugs, is important for CAD management in patients with RA and may also be a promising approach among the general population.

Humoral Immunity Against HDL Particle: A New Perspective in Cardiovascular Diseases?

BACKGROUND

Autoimmune diseases are closely associated with cardiovascular diseases (CVD). Over the last decades, the comprehension of atherosclerosis, the principal initiator of CVD, evolved from a lipidcentered disease to a predominant inflammatory and immune response-driven disease displaying features of autoimmunity against a broad range of auto-antigens, including lipoproteins. Among them, high density lipoproteins (HDL) are important actors of cholesterol transport and bear several anti-atherogenic properties, raising a growing interest as therapeutic targets to decrease atherosclerosis and CVD burden, with nevertheless rather disappointing results so far. Reflecting HDL composition complexity, autoimmune responses and autoantibodies against various HDL components have been reported.

RESULTS

In this review, we addressed the important complexity of humoral autoimmunity towards HDL and particularly how this autoimmune response could help improving our understanding of HDL biological implication in atherosclerosis and CVD. We also discussed several issues related to specific HDL autoantibody subclasses characteristics, including etiology, prognosis and pathological mechanisms according to Rose criteria.

CONCLUSION

Finally, we addressed the possible clinical value of using these antibodies not only as potential biomarkers of atherogenesis and CVD, but also as a factor potentially mitigating the benefit of HDL-raising therapies.

Cardiovascular Risk Assessment and Therapeutic Implications in Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) suffer from a magnitude of excess cardiovascular risk. A paradoxical lipid pattern has been observed in rheumatoid arthritis patients where low levels of total cholesterol and low-density lipoprotein are associated with a higher risk of cardiovascular disease. This paper aims to break down the evidence explaining why patients with low to normal LDL, and total cholesterol have such excess cardiovascular risk. A component of the enhanced cardiovascular risk is systemic inflammation and the subsequent pro-atherogenic dyslipidemia patterns. Due to this "lipid paradox," current risk algorithms and guidelines designed for the general population may underestimate cardiovascular risk in patients with rheumatoid arthritis. The purpose of this paper is to critically evaluate some of the discrepancies and layers of cardiovascular risk in RA patients, the role RA medication may have in mitigating or increasing cardiovascular risk, and the possible role of statin therapy.

Low high-density lipoprotein cholesterol and high triglycerides lipid profile in neuromyelitis optica spectrum disorder: Associations with disease activity and disability

BACKGROUND

Altered lipid metabolism is a feature of systemic autoimmune diseases. Dyslipidemia is associated with the disease activity and progression in patients with multiple sclerosis. However, in neuromyelitis optica spectrum disorder (NMOSD), changes in the lipid profile and the associations between specific lipid levels and disease activity/disability are unknown.

METHODS

Serum samples (N = 148) were collected from 53 patients with aquaporin-4 (AQP4)-positive NMOSD when they were not treated with lipid lowering agents. Fasting lipid (total cholesterol, triglyceride [TG], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol) levels were compared between 39 patients with NMOSD, not taking steroids, and 142 age-, sex-, and body mass index-matched healthy controls. In addition, we analyzed the differences in the lipid profile between attack and remission samples and the associations between lipid profiles and clinical outcome in all 148 samples from 53 patients. The generalized estimating equation was used.

RESULTS

Patients with NMOSD showed lower HDL-C and higher TG levels compared to healthy controls (p = 0.017 and p < 0.001, respectively). HDL-C level was significantly lower during attack than remission (β = -7.851; p = 0.035), and TG level had positive correlation with EDSS scores (β = 0.014; p = 0.002) regardless of disease activity status. However, enhanced lesions on magnetic resonance imaging were not associated with lipid profiles.

CONCLUSION

Dyslipidemia with low HDL-C and high TG correlated disease activity and disability in AQP4-positive NMOSD. It remains to be elucidated whether altered lipid metabolism contributes to deleterious immune response, possibly through inflammation, or is secondary to neurological disability in NMOSD.

Changes in serum adipokines profile and insulin resistance in patients with rheumatoid arthritis treated with anti-TNF-α

Background: Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by an altered glucose and lipid metabolism. Tumor necrosis factor alpha (TNF-α) is involved in the pathogenesis of both RA and metabolic syndrome. This study evaluated the effects of anti-TNF-α agents (adalimumab, etanercept, infliximab) on lipid and glucose metabolism in patients with RA.Methods: A total of 33 RA, biological therapy-naive patients were recruited. Changes in Disease Activity, Body Mass Index, resistin, leptin and adiponectin serum levels, lipid profile, atherogenic index, insulin sensitivity index, and insulin resistance index were evaluated at baseline and after anti-TNF-α treatments.Results: Anti-TNF-α treatment was effective in reducing disease activity. An inverse relationship between disease activity and adiponectin levels was found, whereas leptin and resistin levels directly correlated with disease activity. TNF-α therapy significantly reduced leptin, resistin, and increased adiponectin. TNF-α inhibition resulted in a reduction of atherogenic index and insulin resistance index while increased insulin sensitivity index.Conclusion: Anti-TNF-α agents could have a crucial role in modifying the impact of lipid profile and glucose levels dysregulation in RA patients. TNF-α inhibition may be a potential strategy for the prevention of metabolic syndrome and could play a role in the reduction of cardiovascular risk in RA.

Anti-Atherosclerotic Effects of Fruits of Vitex rotundifolia and Their Isolated Compounds via Inhibition of Human LDL and HDL Oxidation

Low-density lipoprotein (LDL) and high-density lipoprotein (HDL) oxidation are well known to increase the risk for atherosclerosis. In our ongoing research on natural products with inhibitory activities against oxidation of lipoproteins, fruits of Vitex rotundifolia were found to be highly active. There is no report on the effects on LDL and HDL oxidation. Herein, we investigated the inhibitory effects of V. rotundifolia fruit extract and its six compounds, which are: (1) artemetin, (2) casticin, (3) hesperidin, (4) luteolin, (5) vitexin, and (6) vanillic acid, against LDL and HDL oxidation. The LDL and HDL oxidations were determined by measuring production of conjugated dienes and thiobarbituric acid reactive substances, amount of hyperchromicity and carbonyl content, change in electrical charge, and apoA-I aggregation. In addition, the contents of the compounds in the extracts were analyzed using HPLC-DAD. Consequently, extracts of Vitex rotundifolia fruits and compounds 2 and 4 suppressed oxidation of LDL and HDL, showing inhibition of lipid peroxidation, decrease of negative charges in lipoproteins, reduction of hyperchromicity, decrease in carbonyl contents, and prevention of apoA-I aggregation. In particular, compounds 2 and 4 exhibited more potent inhibitory effect on oxidation of LDL and HDL than the extracts, suggesting their protective role against atherosclerosis via inhibition of LDL and HDL oxidation. The contents of artemetin, casticin, and vanillic acid in the extracts were 1.838 ± 0.007, 8.629 ± 0.078, and 1.717 ± 0.006 mg/g, respectively.

Epimedium koreanum Extract and Its Flavonoids Reduced Atherosclerotic Risk via Suppressing Modification of Human HDL

Atherosclerosis is the key factor responsible for cardiovascular events, which is a major cause of morbidities and mortalities worldwide. It is well known that high-density lipoprotein (HDL) oxidation and glycation increases the risk for atherosclerosis. Epimedium koreanum has been used as a traditional oriental medicine for treating erectile dysfunction, kidney diseases, osteoporosis, and breast cancer. However, no reports on the effects of E. koreanum on HDL modification exist. In this study, we investigated the inhibitory effects of E. koreanum extract and its eight flavonoids, which are: (1) anhydroicaritin 3-O-rhamnoside, (2) β-anhydroicaritin, (3–5) epimedins A-C, (6) epimedoside A, (7) icariin, and (8) des-O-methyl-β-anhydroicaritin, against HDL modification. HDLs obtained from pooled human plasma samples were incubated in vitro with E. koreanum extract or each compound in the presence of copper sulfate or fructose. The HDL modifications were evaluated by measuring generation of conjugated dienes, production of thiobarbituric acid reactive substances, change in electrophoretic mobility of apoA-I, advanced glycation end products formation, and apoA-I aggregation. Consequently, E. koreanum extract and compound 8 suppressed HDL modification through inhibition of lipid peroxidation, apoA-I aggregation, negative charge increase, and AGEs formation. In particular, compound 8 showed more potent inhibitory effect on HDL modification than the extracts, suggesting its protective role against atherosclerosis via inhibition of HDL oxidation and glycation.

Proteomics Analysis for Verification of Rheumatoid Arthritis Biomarker Candidates Using Multiple Reaction Monitoring

PURPOSE

Rheumatoid arthritis (RA) is an autoimmune disease in which autoantibodies attack the synovial membrane, causing joint inflammation. Blood tests would offer a powerful, minimally invasive method for early diagnosis of RA. However, no reliable biomarkers for RA are presently available. The aim is to develop biomarkers for RA by multiple reaction monitoring (MRM)-based quantification of candidate biomarkers.

EXPERIMENTAL DESIGN

Proteomics approaches are commonly used to identify and verify disease biomarkers. For discovery of biomarkers for RA, SWATH acquisition is performed and selected candidate biomarkers are validated by MRM. Target serum proteins are compared between patients with RA and healthy controls divided into three groups based on rheumatoid factor level.

RESULTS

A total of 45 differentially expressed proteins are identified, as determined by SWATH acquisition. Of these, 13 proteins are selected as novel candidate biomarkers. A total of five proteins (transthyretin, gelsolin, angiotensinogen, lipopolysaccharide-binding protein, and protein S100-A9) are shown to have the potential to distinguish patients with RA from healthy controls.

CONCLUSIONS AND CLINICAL RELEVANCE

These five proteins may improve the efficiency of diagnosis of RA. MRM can be used to easily diagnose RA by detecting five proteins simultaneously in a single sample with high sensitivity.

Effects of Hypoxia and Bed Rest on Markers of Cardiometabolic Risk: Compensatory Changes in Circulating TRAIL and Glutathione Redox Capacity

In chronic diseases, hypoxia and physical inactivity are associated with atherosclerosis progression. In contrast, a lower mortality from coronary artery disease and stroke is observed in healthy humans residing at high altitude in hypoxic environments. Eleven young, male volunteers completed the following 10-day campaigns in a randomized order: hypoxic ambulatory, hypoxic bed rest and normoxic bed rest. Before intervention, subjects were evaluated in normoxic ambulatory condition. Normobaric hypoxia was achieved in a hypoxic facility simulating 4000 m of altitude. Following hypoxia, either in bed rest or ambulatory condition, markers of cardiometabolic risk shifted toward a more atherogenic pattern consisting of: (a) lower levels of total HDL cholesterol and HDL2 sub-fraction and decreased hepatic lipase; (b) activation of systemic inflammation, as determined by C-reactive protein and serum amyloid A; (c) increased plasma homocysteine; (d) decreased delta-5 desaturase index in cell membrane fatty acids, a marker of insulin sensitivity. Bed rest and hypoxia additively decreased total HDL and delta-5 desaturase index. In parallel to the pro-atherogenic effects, hypoxia activated selected anti-atherogenic pathways, consisting of increased circulating TNF-related apoptosis-inducing ligand (TRAIL), a protective factor against atherosclerosis, membrane omega-3 index and erythrocyte glutathione availability. Hypoxia mediated changes in TRAIL concentrations and redox glutathione capacity (i.e., GSH/GSSG ratio) were greater in ambulatory conditions (+34 ± 6% and +87 ± 31%, respectively) than in bed rest (+17 ± 7% and +2 ± 27% respectively). Hypoxia-induced cardiometabolic risk is blunted by moderate level of physical activity as compared to bed rest. TRAIL and glutathione redox capacity may contribute to the positive interaction between physical activity and hypoxia.

Highlights:

– Hypoxia and bed rest activate metabolic and inflammatory markers of atherogenesis.

– Hypoxia and physical activity activate selected anti-atherogenic pathways.

– Hypoxia and physical activity positive interaction involves TRAIL and glutathione.

Apolipoprotein B binds to enolase-1 and aggravates inflammation in rheumatoid arthritis

OBJECTIVE

Immune cells from patients with rheumatoid arthritis (RA) express more enolase-1 (ENO1) on their surface than those from healthy subjects, and they elicit an enhanced inflammatory response. This study is aimed to identify the ligands of ENO1 that could promote inflammatory loops in vitro and enhance the arthritis severity in vivo.

METHODS

ENO1-binding proteins in RA synovial fluid were identified by mass spectromety, and affinity to ENO1 was evaluated by means of a ligand blotting and binding assay, surface plasmon resonance and confocal microscopy. Proinflammatory response by the interaction between ENO1 and apolipoprotein B (apoB) was tested in vitro and in vivo using peripheral blood mononuclear cells and a K/BxN serum transfer arthritis model and low-density lipoproteins receptor (LDLR) knockout mice.

RESULTS

ApoB in the synovid fluid of patients with RA was identified as a specific ligand to ENO1 with a higher affinity than plasminogen, a known ENO1 ligand. ApoB binding to ENO1 on monocytes elicited the production of tumour necrosis factor-α, interleukins (IL)-1β and IL-6 through both p38 mitogen-activated protein kinase and NF-κB pathways. In the K/BxN serum transfer arthritis model, administration of apoB increased the production of proinflammatory cytokines and exaggerated arthritis severity. The severity of K/BxN serum transfer arthritis in LDLR knockout mice was comparable with wild-type mice.

CONCLUSIONS

A key component of atherogenic lipids, apoB, aggravated arthritis by potentiating the inflammatory response via its interaction with ENO1 expressed on the surface of immune cells. This suggests a novel mechanism by which lipid metabolism regulates chronic inflammation in RA.

Impact of Dietary Cholesterol on the Pathophysiology of Infectious and Autoimmune Disease

Cellular cholesterol metabolism, lipid raft formation, and lipoprotein interactions contribute to the regulation of immune-mediated inflammation and response to pathogens. Lipid pathways have been implicated in the pathogenesis of bacterial and viral infections, whereas altered lipid metabolism may contribute to immune dysfunction in autoimmune diseases, such as systemic lupus erythematosus, multiple sclerosis, and rheumatoid arthritis. Interestingly, dietary cholesterol may exert protective or detrimental effects on risk, progression, and treatment of different infectious and autoimmune diseases, although current findings suggest that these effects are variable across populations and different diseases. Research evaluating the effects of dietary cholesterol, often provided by eggs or as a component of Western-style diets, demonstrates that cholesterol-rich dietary patterns affect markers of immune inflammation and cellular cholesterol metabolism, while additionally modulating lipoprotein profiles and functional properties of HDL. Further, cholesterol-rich diets appear to differentially impact immunomodulatory lipid pathways across human populations of variable metabolic status, suggesting that these complex mechanisms may underlie the relationship between dietary cholesterol and immunity. Given the Dietary Guidelines for Americans 2015⁻2020 revision to no longer include limitations on dietary cholesterol, evaluation of dietary cholesterol recommendations beyond the context of cardiovascular disease risk is particularly timely. This review provides a comprehensive and comparative analysis of significant and controversial studies on the role of dietary cholesterol and lipid metabolism in the pathophysiology of infectious disease and autoimmune disorders, highlighting the need for further investigation in this developing area of research.

Consumption of Cuban Policosanol Improves Blood Pressure and Lipid Profile via Enhancement of HDL Functionality in Healthy Women Subjects: Randomized, Double-Blinded, and Placebo-Controlled Study

Policosanol has been reported to improve blood pressure, lipid profile, and HDL functionality via inhibition of cholesteryl ester transfer protein (CETP) both in vitro and in vivo in zebrafish and human models. However, there are limited reports and randomized, double-blinded trials on policosanol that could advocate the blood pressure-lowering effect in prehypertensive participants. Therefore, we performed in vitro, in vivo, and ex vivo experiments to provide more substantial and concrete data on the blood pressure-lowering effect of policosanol. Consumption of policosanol for 8 weeks enhanced plasma antioxidant activity. In the policosanol group, plasma total cholesterol (TC) and triglyceride (TG) levels were reduced up to 20% and 14%, respectively, and HDL-C level was elevated up to 1.3-fold compared to that at week 0. TG/HDL-C and cholesteryl ester transfer protein (CETP) activities were reduced up to 36% and 20%, respectively. Uptake of oxidized LDL in macrophages was reduced as oxidized species levels were reduced, and HDL₂-associated paraoxonase activities were enhanced by 60% compared to those at week 0. Encapsulation of policosanol into reconstituted HDL (PCO-rHDL) enhanced cholesterol efflux activity and insulin secretion capacity. In conclusion, consumption of policosanol for 8 weeks in healthy female subjects resulted in lowered blood pressure and CETP activity via elevation of HDL/apoA-I contents and enhancement of HDL functionalities, including cholesterol efflux and insulin secretion. These functional enhancements of HDL can contribute to the prevention of aging-related diseases, hypertension, and stroke.

Increased cardiovascular risk in rheumatoid arthritis: mechanisms and implications

Rheumatoid arthritis is a systemic autoimmune disease characterized by excess morbidity and mortality from cardiovascular disease. Mechanisms linking rheumatoid arthritis and cardiovascular disease include shared inflammatory mediators, post-translational modifications of peptides/proteins and subsequent immune responses, alterations in the composition and function of lipoproteins, increased oxidative stress, and endothelial dysfunction. Despite a growing understanding of these mechanisms and their complex interplay with conventional cardiovascular risk factors, optimal approaches of risk stratification, prevention, and treatment in the context of rheumatoid arthritis remain unknown. A multifaceted approach to reduce the burden posed by cardiovascular disease requires optimal management of traditional risk factors in addition to those intrinsic to rheumatoid arthritis such as increased disease activity. Treatments for rheumatoid arthritis seem to exert differential effects on cardiovascular risk as well as the mechanisms linking these conditions. More research is needed to establish whether preferential rheumatoid arthritis therapies exist in terms of prevention of cardiovascular disease. Ultimately, understanding the unique mechanisms for cardiovascular disease in rheumatoid arthritis will aid in risk stratification and the identification of novel targets for meaningful reduction of cardiovascular risk in this patient population.

Practical Management of Cardiovascular Comorbidities in Rheumatoid Arthritis

Cardiovascular (CV) comorbidities are a frequent extra-articular manifestation of rheumatoid arthritis (RA). Cardiovascular disease (CVD) with accelerated atherosclerosis is a major cause of morbidity and mortality in patients with RA. Subclinical CVD may be present since the early phase of RA. Not only traditional but also non-traditional CV risk factors are involved in the pathogenesis of RA-related CVD. Due to the lack of specifically designed randomized clinical trials, it is still unclear which tools to use to perform CV risk assessment, how to interpret the results and which interventions are appropriate in RA patients both to prevent and to manage CVD. Based on the available evidence, we propose a practical approach.