High levels of oxidized fatty acids in HDL are associated with impaired HDL function in patients with active rheumatoid arthritis

UPLC-Triple-TOF-MS-based serum metabonomic revealed the alleviating effect of QingYan Formula on perimenopausal syndrome rats

The study aimed to investigate the relieving effect of QingYan Formula (QYF) in treating perimenopausal syndrome. A combination of metabonomic analysis and in vitro pharmacodynamic experiments was employed to achieve this objective.Over a period of 12 weeks, ovariectomized (OVX) rats were orally administered QYF's 70 % ethanol extract or estradiol valerate (EV). The results demonstrate that QYF restored the estrous cycle of ovariectomized rats and exhibited significant estrogenic activity, as indicated by reversal of uterine and vagina atrophy, improvement of serum estradiol level and decrease of serum luteinizing hormone(LH) level. Additionally, QYF administration effectively reduced high bone turnover and repaired trabecular microstructure damage. Metabonomic analysis of the OVX rats treated with QYF revealed the identification of 55 different metabolites in the serum, out of which 35 may be potential biomarkers. QYF could regulate the disturbed metabolic pathways including the Biosynthesis of unsaturated fatty acids, arachidonic acid metabolism, bile secretion, and steroid hormone biosynthesis. PI3KCA, SRC, and MAPK3 are potential therapeutic targets for QYF therapeutic effects. These findings support the efficacy of QYF in alleviating perimenopausal syndrome and regulating lipid metabolic disorders in OVX rats.

Functional Lipids and Cardiovascular Disease Reduction: A Concise Review

Functional lipids are dietary substances that may have an impact on human health by lowering the risk of chronic illnesses and enhancing the quality of life. Numerous functional lipids have been reported to have potential health benefits in the prevention, management, and treatment of cardiovascular disease, the leading cause of death in the United States. However, there is still insufficient and contradictory information in the literature about their effectiveness and associated mechanisms of action. The objective of this review, therefore, is to evaluate available literature regarding these functional lipids and their health benefits. Various studies have been conducted to understand the links between functional lipids and the prevention and treatment of chronic diseases. Recent studies on phytosterols have reported that CLA, medium-chain triglycerides, and omega-3 and 6 fatty acids have positive effects on human health. Also, eicosanoids, which are the metabolites of these fatty acids, are produced in relation to the ratio of omega-3 to omega-6 polyunsaturated fatty acids and may modulate disease conditions. These functional lipids are available either in dietary or supplement forms and have been proven to be efficient, accessible, and inexpensive to be included in the diet. However, further research is required to properly elucidate the dosages, dietary intake, effectiveness, and their mechanisms of action in addition to the development of valid disease biomarkers and long-term effects in humans.

High fat diet increases the severity of collagen-induced arthritis in mice by altering the gut microbial community

OBJECTIVES

Research has demonstrated that obesity may be associated with rheumatoid arthritis (RA). In addition, gut microbiota and its metabolites contribute to the occurrence and development of RA and obesity. However, the mechanism by which obesity affects RA remains unclear. In this study, we aimed to investigate whether gut microbiota and their metabolites alter the effects of high fat diet (HFD) on the severity of collagen-induced arthritis (CIA) in mice.

METHODS

Briefly, mice were divided into normal group (N), CIA model group (C), HFD group (T), and HFD CIA group (CT). Hematoxylin and Eosin staining(HE) and Safranin O-fast green staining were conducted, and levels of blood lipid and inflammatory cytokines were measured. 16S rDNA sequencing technique and liquid chromatography-mass spectrometry (LC-MS)-based metabolomics were performed to explore changes in the microbiota structure to further reveal the pathomechanism of HFD on CIA.

RESULTS

HFD aggravated the severity of CIA in mice. The CT group had the highest proportion of microbial abundance of Blautia, Oscillibacter, Ruminiclostridium-9, and Lachnospiraceae UCG 006 at the genus level, but had a lower proportion of Alistipes. Additionally, the fecal metabolic phenotype of the combined CT group shows significant changes, with differential metabolites enriched in 9 metabolic pathways, including primary bile acid biosynthesis, arginine biosynthesis, sphingolipid metabolism, purine metabolism, linoleic acid metabolism, oxytocin signaling pathway, aminoacyl-tRNA biosynthesis, the pentose phosphate pathway, and sphingolipid signaling pathway. Correlation analysis revealed that some of the altered gut microbiota genera were strongly correlated with changes in fecal metabolites, total cholesterol (TC), triglyceride (TG), and inflammatory cytokine levels.

CONCLUSIONS

This study shows that HFD may aggravate inflammatory reaction in CIA mice by altering the gut microbiota and metabolic pathways.

Oxylipin transport by lipoprotein particles and its functional implications for cardiometabolic and neurological disorders

Lipoprotein metabolism is critical to inflammation. While the periphery and central nervous system (CNS) have separate yet connected lipoprotein systems, impaired lipoprotein metabolism is implicated in both cardiometabolic and neurological disorders. Despite the substantial investigation into the composition, structure and function of lipoproteins, the lipoprotein oxylipin profiles, their influence on lipoprotein functions, and their potential biological implications are unclear. Lipoproteins carry most of the circulating oxylipins. Importantly, lipoprotein-mediated oxylipin transport allows for endocrine signaling by these lipid mediators, long considered to have only autocrine and paracrine functions. Alterations in plasma lipoprotein oxylipin composition can directly impact inflammatory responses of lipoprotein metabolizing cells. Similar investigations of CNS lipoprotein oxylipins are non-existent to date. However, as APOE4 is associated with Alzheimer's disease-related microglia dysfunction and oxylipin dysregulation, ApoE4-dependent lipoprotein oxylipin modulation in neurological pathologies is suggested. Such investigations are crucial to bridge knowledge gaps linking oxylipin- and lipoprotein-related disorders in both periphery and CNS. Here, after providing a summary of existent literatures on lipoprotein oxylipin analysis methods, we emphasize the importance of lipoproteins in oxylipin transport and argue that understanding the compartmentalization and distribution of lipoprotein oxylipins may fundamentally alter our consideration of the roles of lipoprotein in cardiometabolic and neurological disorders.

[Correlation between dyslipidemia and rheumatoid arthritis associated interstitial lung disease]

OBJECTIVE

To study the correlation between dyslipidemia and rheumatoid arthritis associa-ted interstitial lung disease (RA-ILD) by retrospective analysis of the clinical data.

METHODS

The clinical data of patients with rheumatoid arthritis (RA), who were hospitalized in the Department of Rheumatism and Immunology of Peking University Shenzhen Hospital from January 2015 to July 2020 and fulfilled the criteria of the 2010 Rheumatoid Arthritis Classification Criteria established by American College of Rheumatology/European League Against Rheumatism collaborative initiative, were collected and analyzed.

RESULTS

There were 737 RA patients included, of whom 282(38.26%)were with interstitial lung disease (ILD). The median time from the onset of the first RA-related clinical symptoms to the onset of ILD was 13 years (95%CI 11.33-14.67). By multivariate Logistic regression analysis, we found that low-density lipoprotein cholesterol (LDL-C) was an independent risk factor for RA-ILD (OR 1.452, 95%CI 1.099-1.918, P=0.009), whereas high-density lipoprotein cholesterol (HDL-C) was a protective factor for RA-ILD (OR 0.056, 95%CI 0.025-0.125, P < 0.001). The RA patients with high LDL-C or low HDL-C had higher incidence of ILD than that of the RA patients with normal LDL-C or HDL-C(57.45% vs. 36.96%, P < 0.001; 47.33% vs. 33.81%, P < 0.001, respectively). The median time of ILD onset in the RA patients with low HDL-C was shorter than that of the RA patients with normal HDL-C [10.0(95%CI 9.33-10.67)years vs.17.0 (95%CI 14.58-19.42) years, P < 0.001]. HDL-C level was negatively correlated with disease activity. Among the RA-ILD patients, the patients with low HDL-C had higher percentage of usual interstitial pneumonia (UIP) then that of the patients with normal HDL-C (60.00% vs. 53.29%, P=0.002). The RA-ILD patients with high LDL-C had higher incidence rate of decrease in forced vital capacity (FVC) than that of the RA-ILD patients with normal LDL-C (50.00% vs. 21.52%, P=0.015). The RA-ILD patients with low HDL-C had higher incidence rate of decrease in FVC (26.92% vs. 16.18%, P=0.003) and carbon monoxide diffusion (80.76% vs. 50.00%, P=0.010) than that of RA-ILD patients with normal HDL-C.

CONCLUSION

LDL-C was possibly a potential independent risk factor for RA-ILD. HDL-C was possibly a potential protective factor for RA-ILD. HDL-C level was negatively correlated with disease activity of RA. The median time of ILD onset in the RA patients with low HDL-C was significantly shorter than that of the RA patients with normal HDL-C.

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.

Oxidative stress, mitochondrial dysfunction, and respiratory chain enzyme defects in inflammatory myopathies

We investigated the relationship between oxidative stress and inflammatory myopathies. We searched in the current literature the role of mitochondria and respiratory chain defects as sources of oxidative stress and reactive oxygen species production that led to muscle weakness and fatigue. Different molecules and pathways contribute to redox milieu, reactive oxygen species generation, accumulation of misfolded and carbonylated proteins that lose their ability to fulfil cellular activities. Small peptides and physical techniques proved, in mice models, to reduce oxidative stress. We focused on inclusion body myositis, as a major expression of myopathy related to oxidative stress, where mitochondrial abnormalities are causative agents as well. We described the effect of physical exercise in inclusion body myositis that showed to increase strength and to reduce beta amyloid accumulation with subsequent improvement of the mitochondrial functions. We illustrated the influence of epigenetic control on the immune system by non-coding genetic material in the interaction between oxidative stress and inflammatory myopathies.

Diagnostic biomarker panels of osteoarthritis: UPLC-QToF/MS-based serum metabolic profiling

Osteoarthritis (OA) is the most common joint disease in the world, characterized by pain and loss of joint function, which has led to a serious reduction in the quality of patients' lives. In this work, ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-QToF/MS) in conjunction with multivariate pattern recognition methods and an univariate statistical analysis scheme were applied to explore the serum metabolic signatures within OA group (n = 31), HC (healthy controls) group (n = 57) and non-OA group (n = 19) for early diagnosis and differential diagnosis of OA. Based on logistic regression analysis and receiver operating characteristic (ROC) curve analysis, seven metabolites, including phosphatidylcholine (18:0/22:6), p-cresol sulfate and so on, were identified as critical metabolites for the diagnosis of OA and HC and yielded an area under the curve (AUC) of 0.978. The other panel of unknown m/z 239.091, phosphatidylcholine (18:0/18:0) and phenylalanine were found to distinguish OA from non-OA and achieved an AUC of 0.888. These potential biomarkers are mainly involved in lipid metabolism, glucose metabolism and amino acid metabolism. It is expected to reveal new insight into OA pathogenesis from changed metabolic pathways.

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.

Arachidonate 15-lipoxygenase type B: Regulation, function, and its role in pathophysiology

As a lipoxygenase (LOX), arachidonate 15-lipoxygenase type B (ALOX15B) peroxidizes polyenoic fatty acids (PUFAs) including arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA) to their corresponding fatty acid hydroperoxides. Distinctive to ALOX15B, fatty acid oxygenation occurs with positional specificity, catalyzed by the non-heme iron containing active site, and in addition to free PUFAs, membrane-esterified fatty acids serve as substrates for ALOX15B. Like other LOX enzymes, ALOX15B is linked to the formation of specialized pro-resolving lipid mediators (SPMs), and altered expression is apparent in various inflammatory diseases such as asthma, psoriasis, and atherosclerosis. In primary human macrophages, ALOX15B expression is associated with cellular cholesterol homeostasis and is induced by hypoxia. Like in inflammation, the role of ALOX15B in cancer is inconclusive. In prostate and breast carcinomas, ALOX15B is attributed a tumor-suppressive role, whereas in colorectal cancer, ALOX15B expression is associated with a poorer prognosis. As the biological function of ALOX15B remains an open question, this review aims to provide a comprehensive overview of the current state of research related to ALOX15B.

High-Throughput Chinmedomics Strategy Discovers the Quality Markers and Mechanisms of Wutou Decoction Therapeutic for Rheumatoid Arthritis

Wutou decoction (WTD) is a traditional Chinese medicine prescription for the treatment of rheumatoid arthritis (RA), and this study systematically analyzed the metabolic mechanism and key pharmacodynamic components of WTD in RA rats by combining untargeted metabolomics and serum pharmacochemistry of traditional Chinese medicine to enrich the evidence of WTD quality markers (Q-markers) studies. WTD prevented synovial edema in RA rats and reduced tumor necrosis factor-alpha and interleukin 6 levels in rat serum, according to the results of an enzyme-linked immunosorbent examination and histopathological inspection. In model rats, pattern recognition and multivariate statistical analysis revealed 24 aberrant metabolites that disrupted linoleic acid metabolism, arachidonic acid metabolism, arginine and proline metabolism, etc. However, continued dosing of WTD for 28 days reversed 13 abnormal metabolites, which may be an important therapeutic mechanism from a metabolomic perspective. Importantly, 12 prototypical components and 16 metabolites from WTD were characterized in RA rat serum. The results of Pearson correlation analysis showed that aconitine, L-ephedrine, L-methylephedrine, quercetin, albiflorin, paeoniflorigenone, astragaline A, astragaloside II, glycyrrhetic acid, glycyrrhizic acid, licurazide, and isoliquiritigenin are the key pharmacological components that regulate the metabolism of RA rats, and they are identified as Q-markers. In sum, utilizing metabolomics and serum pharmacochemistry of traditional Chinese medicine, the metabolic mechanisms and Q-markers of WTD therapy in RA rats were revealed, providing a theoretical basis for the quality control investigation of WTD.

High levels of oxidized fatty acids in HDL impair the antioxidant function of HDL in patients with diabetes

AIMS

Previous studies demonstrate that the antioxidant functions of high-density lipoprotein (HDL) are impaired in diabetic patients. The composition of HDL plays an important role in maintaining the normal functionality of HDL. In this study, we compared the levels of oxidized fatty acids in HDL from diabetic subjects and non-diabetic healthy controls, aiming to investigate the role of oxidized fatty acids in the antioxidant property of HDL.

METHODS

HDL was isolated from healthy subjects (n=6) and patients with diabetes (n=6, hemoglobin A1c ≥ 9%, fasting glucose ≥ 7 mmol/L) using a dextran sulfate precipitation method. Cholesterol efflux capacity mediated by HDL was measured on THP-1 derived macrophages. The antioxidant capacity of HDL was evaluated with dichlorofluorescein-based cellular assay in human aortic endothelial cells. Oxidized fatty acids in HDL were determined by liquid chromatography-tandem mass spectrometry. The correlations between the levels of oxidized fatty acids in HDL and the endothelial oxidant index in cells treated with HDLs were analyzed through Pearson's correlation analyses, and the effects of oxidized fatty acids on the antioxidant function of HDL were verified in vitro.

RESULTS

The cholesterol efflux capacity of HDL and the circulating HDL-cholesterol were similar in diabetic patients and healthy controls, whereas the antioxidant capacity of HDL was significantly decreased in diabetic patients. There were higher levels of oxidized fatty acids in HDL isolated from diabetic patients, which were strongly positively correlated with the oxidant index of cells treated with HDLs. The addition of a mixture of oxidized fatty acids significantly disturbed the antioxidant activity of HDL from healthy controls, while the apolipoprotein A-I mimetic peptide D-4F could restore the antioxidant function of HDL from diabetic patients.

CONCLUSION

HDL from diabetic patients displayed substantially impaired antioxidant activity compared to HDL from healthy subjects, which is highly correlated with the increased oxidized fatty acids levels in HDL.

HDL and persistent inflammation immunosuppression and catabolism syndrome

PURPOSE OF REVIEW

This study reviews the mechanisms of HDL cholesterol immunomodulation in the context of the mechanisms of chronic inflammation and immunosuppression causing persistent inflammation, immunosuppression and catabolism syndrome (PICS) and describes potential therapies and gaps in current research.

RECENT FINDINGS

Low HDL cholesterol is predictive of acute sepsis severity and outcome. Recent research has indicated apolipoprotein is a prognostic indicator of long-term outcomes. The pathobiologic mechanisms of PICS have been elucidated in the past several years. Recent research of the interaction of HDL pathways in related chronic inflammatory diseases may provide insights into further mechanisms and therapeutic targets.

SUMMARY

HDL significantly influences innate and adaptive immune pathways relating to chronic disease and inflammation. Further research is needed to better characterize these interactions in the setting of PICS.

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.

Fatty Acids and Oxylipins in Osteoarthritis and Rheumatoid Arthritis-a Complex Field with Significant Potential for Future Treatments

Purpose of Review

Osteoarthritis (OA) and rheumatoid arthritis (RA) are characterized by abnormal lipid metabolism manifested as altered fatty acid (FA) profiles of synovial fluid and tissues and in the way dietary FA supplements can influence the symptoms of especially RA. In addition to classic eicosanoids, the potential roles of polyunsaturated FA (PUFA)-derived specialized pro-resolving lipid mediators (SPM) have become the focus of intensive research. Here, we summarize the current state of knowledge of the roles of FA and oxylipins in the degradation or protection of synovial joints.

Recent Findings

There exists discordance between the large body of literature from cell culture and animal experiments on the adverse and beneficial effects of individual FA and the lack of effective treatments for joint destruction in OA and RA patients. Saturated 16:0 and 18:0 induce mostly deleterious effects, while long-chain n-3 PUFA, especially 20:5n-3, have positive influence on joint health. The situation can be more complex for n-6 PUFA, such as 18:2n-6, 20:4n-6, and its derivative prostaglandin E₂, with a combination of potentially adverse and beneficial effects. SPM analogs have future potential as analgesics for arthritic pain.

Summary

Alterations in FA profiles and their potential implications in SPM production may affect joint lubrication, synovial inflammation, pannus formation, as well as cartilage and bone degradation and contribute to the pathogeneses of inflammatory joint diseases. Further research directions include high-quality randomized controlled trials on dietary FA supplements and investigations on the significance of lipid composition of microvesicle membrane and cargo in joint diseases.

Biologics and atherosclerotic cardiovascular risk in rheumatoid arthritis: a review of evidence and mechanistic insights

Introduction: Cardiovascular disease is a leading comorbidity in rheumatoid arthritis. Timely introduction of biologic therapies in a treat-to-target approach has optimized disease-related outcomes and attenuated accrual of comorbidities, including cardiovascular risk.Areas covered: A literature search in MEDLINE (via PubMed) was performed between January 2009 and November 2020. This manuscript explores recent developments in atherosclerotic cardiovascular risk in RA compared with non-RA individuals; it synopsizes differences in vascular function and inflammation, prevalence, burden, vulnerability, and progression of atherosclerotic plaque and their underlying cellular and molecular mechanisms. Finally, it reviews the recent literature on cardioprotective benefits of biologics and draws mechanistic links with inhibition of new plaque formation, stabilization of high-risk lesions and improvement in endothelial function, arterial stiffness, lipid metabolism, and traditional cardiac risk factors.Expert opinion: Increasing evidence points to a solid cardioprotective influence of earlier, longer, and ongoing use of biologic treatments in RA. Nevertheless, the precise mechanistic effects of plaque progression and remodeling, vascular stiffness, endothelial dysfunction, lipid metabolism, and traditional cardiac risk factors are less rigorously characterized.

High Density Lipoprotein Cholesterol Efflux Capacity and Atherosclerosis in Cardiovascular Disease: Pathophysiological Aspects and Pharmacological Perspectives

Over the years, the relationship between high-density lipoprotein (HDL) and atherosclerosis, initially highlighted by the Framingham study, has been revealed to be extremely complex, due to the multiple HDL functions involved in atheroprotection. Among them, HDL cholesterol efflux capacity (CEC), the ability of HDL to promote cell cholesterol efflux from cells, has emerged as a better predictor of cardiovascular (CV) risk compared to merely plasma HDL-cholesterol (HDL-C) levels. HDL CEC is impaired in many genetic and pathological conditions associated to high CV risk such as dyslipidemia, chronic kidney disease, diabetes, inflammatory and autoimmune diseases, endocrine disorders, etc. The present review describes the current knowledge on HDL CEC modifications in these conditions, focusing on the most recent human studies and on genetic and pathophysiologic aspects. In addition, the most relevant strategies possibly modulating HDL CEC, including lifestyle modifications, as well as nutraceutical and pharmacological interventions, will be discussed. The objective of this review is to help understanding whether, from the current evidence, HDL CEC may be considered as a valid biomarker of CV risk and a potential pharmacological target for novel therapeutic approaches.

High- density lipoprotein function is abnormal in idiopathic inflammatory myopathies

OBJECTIVE

Damage to the vascular endothelium is strongly implicated in the pathogenesis of idiopathic inflammatory myopathies (IIM). Normally, high-density lipoprotein (HDL) protects the vascular endothelium from damage from oxidized phospholipids, which accumulate under conditions of oxidative stress. The current work evaluated the antioxidant function of HDL in IIM patients.

METHODS

HDL's antioxidant function was measured in IIM patients using a cell-free assay, which assesses the ability of isolated patient HDL to inhibit oxidation of low-density lipoproteins and is reported as the HDL inflammatory index (HII). Cholesterol profiles were measured for all patients, and subgroup analysis included assessment of oxidized fatty acids in HDL and plasma MPO activity. A subgroup of IIM patients was compared with healthy controls.

RESULTS

The antioxidant function of HDL was significantly worse in patients with IIM (n = 95) compared with healthy controls (n = 41) [mean (S.d.) HII 1.12 (0.61) vs 0.82 (0.13), P < 0.0001]. Higher HII associated with higher plasma MPO activity [mean (S.d.) 13.2 (9.1) vs 9.1 (4.6), P = 0.0006] and higher oxidized fatty acids in HDL. Higher 5-hydroxyeicosatetraenoic acid in HDL correlated with worse diffusion capacity in patients with interstitial lung disease (r = -0.58, P = 0.02), and HDL's antioxidant function was most impaired in patients with autoantibodies against melanoma differentiation-associated protein 5 (MDA5) or anti-synthetase antibodies. In multivariate analysis including 182 IIM patients, higher HII was associated with higher disease activity and DM diagnosis.

CONCLUSION

The antioxidant function of HDL is abnormal in IIM patients and may warrant further investigation for its role in propagating microvascular inflammation and damage in this patient population.

Insights in the Role of Lipids, Oxidative Stress and Inflammation in Rheumatoid Arthritis Unveiled by New Trends in Lipidomic Investigations

Rheumatoid arthritis (RA) is a highly debilitating chronic inflammatory autoimmune disease most prevalent in women. The true etiology of this disease is complex, multifactorial, and is yet to be completely elucidated. However, oxidative stress and lipid peroxidation are associated with the development and pathogenesis of RA. In this case, oxidative damage biomarkers have been found to be significantly higher in RA patients, associated with the oxidation of biomolecules and the stimulation of inflammatory responses. Lipid peroxidation is one of the major consequences of oxidative stress, with the formation of deleterious lipid hydroperoxides and electrophilic reactive lipid species. Additionally, changes in the lipoprotein profile seem to be common in RA, contributing to cardiovascular diseases and a chronic inflammatory environment. Nevertheless, changes in the lipid profile at a molecular level in RA are still poorly understood. Therefore, the goal of this review was to gather all the information regarding lipid alterations in RA analyzed by mass spectrometry. Studies on the variation of lipid profile in RA using lipidomics showed that fatty acid and phospholipid metabolisms, especially in phosphatidylcholine and phosphatidylethanolamine, are affected in this disease. These promising results could lead to the discovery of new diagnostic lipid biomarkers for early diagnosis of RA and targets for personalized medicine.

Suppression of inflammatory arthritis in human serum paraoxonase 1 transgenic mice

Paraoxonase 1(PON1) is an HDL-associated protein, which metabolizes inflammatory, oxidized lipids associated with atherosclerotic plaque development. Because oxidized lipid mediators have also been implicated in the pathogenesis of rheumatoid arthritis (RA), we evaluated the role of PON1 in murine inflammatory arthritis. K/BxN serum transfer (STIA) or collagen antibody transfer (CAIA) was used for arthritis induction in B6 mice homozygous for the PON1 human transgene [PON1Tg], PON1 knock-out mice [PON1KO], and wild type littermate control mice [WT]. Experiments were also performed in K/BxN mice with chronic arthritis, and in RA patients and healthy controls. Arthritis activity in K/BxN mice was associated with a marked dyslipidemia, lower PON1 activity and higher bioactive lipid mediators (BLM), as well as a dysregulated hepatic lipid gene expression profile. Higher serum PON1 activity correlated with lower BLM and lower arthritis activity in both K/BxN mice and RA patients. Overexpression of the human PON1 transgene was associated with reduced inflammatory arthritis, which correlated strongly with higher circulating PON1 activity, upregulation of the hepatic glutathione pathway, and reduction of circulating BLM. These results implicate PON1 as a potential novel therapeutic target for joint disease in RA with potential for vascular benefit, which warrants further investigation.

The Effects of Linoleic Acid Consumption on Lipid Risk Markers for Cardiovascular Disease in Healthy Individuals: A Review of Human Intervention Trials

Cardiovascular disease (CVD) is the leading cause of death worldwide. Risk factors for developing this disease include high serum concentrations of total cholesterol, triglycerides, low-density lipoproteins, very-low density lipoproteins, and low concentrations of high-density lipoproteins. One proposed dietary strategy for decreasing risk factors involves replacing a portion of dietary saturated fatty acids with mono- and polyunsaturated fatty acids (PUFAs). The essential omega-6 PUFA, linoleic acid (LA), is suggested to decrease the risk for CVD by affecting these lipid risk markers. Reviewing human intervention trials will provide further evidence of the effects of LA consumption on risk factors for CVD. PubMed was used to search for peer-reviewed articles. The purpose of this review was: (1) To summarize human intervention trials that studied the effects of LA consumption on lipid risk markers for CVD in healthy individuals, (2) to provide mechanistic details, and (3) to provide recommendations regarding the consumption of LA to decrease the lipid risk markers for CVD. The results from this review provided evidence that LA consumption decreases CVD lipid risk markers in healthy individuals.

Sulfated polysaccharide from Gracilaria caudata reduces hypernociception and inflammatory response during arthritis in rodents

Polysaccharide from marine alga Gracilaria caudata has potential health benefits, such as anti-inflammatory, gastroprotective and antidiarrheal effects. Here, we investigated the effect of a sulfated polysaccharide from G. caudata (SP-GC) on hypernociception and inflammatory response in arthritis models. The animals received SP-GC (3, 10 or 30 mg/kg) 1 h before tibio-tarsal injection of zymosan. Hypernociception, histopathology, edema, vascular permeability, myeloperoxidase (MPO) activity, cell influx, interleukin (IL)-1β and nitric oxide (NO) levels were evaluated in acute phase. In another protocol, animals received SP-GC (30 mg/kg) 2 h post-complete Freund's adjuvant (CFA). Hypernociception, edema and arthritis index were determined in acute, sub-chronic and chronic phases. Rota-rod test measured the motor performance. SP-GC significantly reduced, in a dose-dependent manner, the zymosan-induced hypernociception with maximal effect at 30 mg/kg. The microscopic inflammation, joint edema, MPO activity, cell influx, IL-1β and NO levels were also reduced by SP-GC. In the CFA-induced arthritis, SP-GC inhibits the hypernociception, edema and arthritic index in acute, sub-chronic and chronic phases. SP-GC did not alter the motor performance of animals. In conclusion, SP-GC exerts protective effect in models of arthritis due to the modulation of cell influx, IL-1β and NO levels, culminating in the reduction of hypernociception and edema.

Lipid management in rheumatoid arthritis: a position paper of the Working Group on Cardiovascular Pharmacotherapy of the European Society of Cardiology

Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity, partly due to alterations in lipoprotein quantity, quality and cell cholesterol trafficking. Although cardiovascular disease significantly contributes to mortality excess in RA, cardiovascular prevention has been largely insufficient. Because of limited evidence, optimal strategies for lipid management (LM) in RA have not been determined yet, and recommendations are largely based on expert opinions. In this position paper, we describe abnormalities in lipid metabolism and introduce a new algorithm for estimation of cardiovascular risk (CVR) and LM in RA. The algorithm stratifies patients according to RA-related factors impacting CVR (such as RA activity and severity and medication). We propose strategies for monitoring of lipid parameters and treatment of dyslipidaemia in RA (including lifestyle, statins and other lipid-modifying therapies, and disease modifying antirheumatic drugs). These opinion-based recommendations are meant to facilitate LM in RA until more evidence is available.

HDL Cholesterol as a Marker of Disease Severity and Prognosis in Patients with Pulmonary Arterial Hypertension

The impact of high-density lipoprotein (HDL) cholesterol on the development of atherosclerosis and diseases of systemic circulation has been well documented both in experimental and registry studies. Recent discoveries in pulmonary arterial hypertension (PAH) revealed a significant impact of HDL on pulmonary artery vasoreactivity and patients' prognosis. The vasoprotective activity of HDL primarily involves vascular endothelium that also plays a central role in pulmonary arterial hypertension (PAH) pathobiology. However, the exact mechanism in which this lipoprotein fraction exerts its effect in pulmonary circulation is still under investigation. This paper reviews potential vasoprotective mechanisms of HDL in pulmonary circulation and presents current clinical reports on the role of HDL in PAH patients.

Accelerated Atherosclerosis in Rheumatoid Arthritis: Mechanisms and Treatment

Background:

Rheumatoid arthritis (RA) is a chronic systemic autoimmune inflammatory disorder that increases the risk of developing cardiovascular disease. There is accumulating evidence that the RA disease state accelerates the formation of atherosclerotic plaques. Treatments for RA improve joint symptomatology and may reduce inflammation, but consideration of their effects on the cardiovascular system is generally low priority.

Objective:

Since cardiovascular disease is the leading cause of mortality in RA patients, the impact of RA therapies on atherosclerosis is an area in need of attention and the focus of this review.

Results:

The drugs used to treat RA may be analgesics, conventional disease-modifying anti-rheumatic drugs, and/or biologics, including antibodies against the cytokine tumor necrosis factor-α. Pain relievers such as nonselective non-steroidal anti-inflammatory drugs and cyclooxygenase inhibitors may adversely affect lipid metabolism and cyclooxygenase inhibitors have been associated with increased adverse cardiovascular events, such as myocardial infarction and stroke. Methotrexate, the anchor disease-modifying anti-rheumatic drug in RA treatment has multiple atheroprotective advantages and is often combined with other therapies. Biologic inhibitors of tumor necrosis factor-α may be beneficial in preventing cardiovascular disease because tumor necrosis factor-α promotes the initiation and progression of atherosclerosis. However, some studies show a worsening of the lipid profile in RA with blockade of this cytokine, leading to higher total cholesterol and triglycerides.

Conclusion:

Greater understanding of the pharmacologic activity of RA treatments on the atherosclerotic process may lead to improved care, addressing both damages to the joints and heart.

The impact of aerobic and isometric exercise on different measures of dysfunctional high-density lipoprotein in patients with hypertension

BACKGROUND

Exercise training increases high-density lipoprotein (HDL) cholesterol, but its effect on HDL function is unclear. In hypertensives, exercise improves endothelial dysfunction, which is related to HDL function. In the present study, we assess for the first time the effects of different exercise modalities on two cell-free assays of HDL function.

DESIGN

The study was conducted as a prospective randomized controlled trial in 75 hypertensive patients.

METHODS

Patients were randomized in three groups: (a) handgrip isometric training five times weekly; (b) placebo-handgrip; and (c) aerobic exercise training at least three times per week. HDL function was assessed in serum samples at baseline and after 12 weeks of training by two independent assays that determine the proinflammatory phenotype (haptoglobin content) of a specific amount of HDL (Haptoglobin-HDL [HPHDL]) and oxidized HDL (HDLox) as a measure of reduced antioxidant function of HDL. HDL function measures were normalized by the measures of a pooled control of sera from healthy participants and by HDL-C levels (normalized ratio, no units).

RESULTS

Aerobic exercise led to significant reduction of the HDLox from 0.99 ± 0.27 to 0.90 ± 0.29 (no units, p = 0.03). The HPHDL did not change in any training group. Changes of HDLox correlated with reduction of the systolic blood pressure only after aerobic exercise (R = 0.64, p = 0.03).

CONCLUSIONS

Aerobic but not isometric exercise improves the antioxidant function of HDL in patients with hypertension. This improvement correlates positively with reductions of blood pressure.

Integrated Serum and Fecal Metabolomics Study of Collagen-Induced Arthritis Rats and the Therapeutic Effects of the Zushima Tablet

The Zushima tablet (ZT) has been used for decades in the clinical treatment of rheumatoid arthritis (RA) in China. However, its therapeutic mechanism is unclear. In this study, we aimed to explore the distinctive metabolic patterns in collagen-induced arthritis (CIA) rats and evaluate the therapeutic effects of ZT on RA using untargeted serum and fecal metabolomics approaches based on gas chromatography coupled with mass spectrometry. Body weight, hind paw swelling, TNF-α and IL-1β levels, arthritis scores, and histopathological parameters were assessed. In the metabolomics study, 31 altered metabolites in the serum and 30 in the feces were identified by comparing the model with the control group using statistical processing. These altered metabolites revealed that the tricarboxylic acid cycle, glycolysis metabolism, fatty acid metabolism, and purine metabolism were disturbed in CIA rats, and most of these altered metabolites including l-isoleucine, l-aspartic acid, pyruvic acid, cholic acid, and hypoxanthine, were rectified by ZT. Furthermore, short-chain fatty acids in feces were quantitatively determined, and the results showed that ZT could regulate the levels of propionate, butyrate, and valerate in CIA rats. Then, gut microbiota were analyzed by 16S rRNA analysis. Our results showed that Firmicutes and Bacteroidetes were the most abundant bacteria in rats. The levels of 19 types of bacteria at the family level were altered in RA rats, and most of them could be regulated by ZT. This study demonstrated that metabolomics analysis is a powerful tool for providing novel insight into RA and for elucidating the potential mechanism of ZT.

A short-term increase in dietary cholesterol and fat intake affects high-density lipoprotein composition in healthy subjects

BACKGROUND AND AIMS

High-cholesterol and high-fat diets alter biochemical composition and anti-oxidant properties of high-density lipoproteins (HDL) in animals. Whether this occurs in humans is unknown. Therefore, we examined the effect of a short-term elevation in dietary cholesterol and fat intake on HDL composition in healthy subjects.

METHODS AND RESULTS

In a randomized, crossover clinical trial, 14 healthy young volunteers followed a 14-day low-cholesterol/low-fat diet (LChF) and a 14-day isocaloric high-cholesterol/high-fat diet (HChF) in a random order. After each diet, we measured HDL concentrations of hydroxyeicosatetraenoic acids (HETE), hydroxyoctadecadienoic acids (HODE), and haptoglobin, as well as serum amyloid A (SAA) and paroxonase-1 activity (PON-1). HDL concentrations of 15-HETE (+254%, p = 0.002), 5-HETE (+116%, p = 0.004), 13-HODE (+102%, p = 0.049), and SAA levels (+75%, p = 0.007) were significantly higher after the HChF than after the LChF. Furthermore, haptoglobin was marginally increased (+32%, p = 0.091) while PON-1 activity was unaffected (-16%, p = 0.366) by the HChF.

CONCLUSION

In healthy subjects, a short-term elevation in dietary cholesterol and fat intake increases HDL lipid hydroperoxide content (15-HETE, 5-HETE, 13-HODE) and SAA levels, which are key features of dysfunctional HDL. This is the first study showing that a physiologic manipulation of dietary cholesterol and fat intake affects HDL lipidome and proteome in healthy subjects independently of weight changes.

CLINICAL TRIAL REGISTRATION

NCT02549144.