Is Lipoprotein-Associated Phospholipase A2 a Link between Inflammation and Subclinical Atherosclerosis in Rheumatoid Arthritis?

Heart rate variability and cardiovascular risk factors in patients with rheumatoid arthritis: A longitudinal study

BACKGROUND

It is established that the risk of cardiovascular disease (CVD) is increased in patients with Rheumatoid Arthritis (RA). Heart rate variability (HRV) is a method for evaluating the activity in the cardiac autonomic nervous system. Our aim was to assess the longitudinal development of HRV in patients with RA and compare with healthy controls. Furthermore, we wanted to investigate associations between HRV, inflammatory disease activity and cardiovascular complications in patients with RA over time.

METHOD

HRV was assessed with frequency-domain analysis at baseline and after five years in 50 patients with early RA, all being younger than 60 years. HRV indices were age-adjusted based on the estimated age-dependency in 100 age and sex matched healthy controls. Additionally, clinical data including serological markers, disease activity, and blood pressure were collected from the patients. Eleven years after inclusion CVD was assessed.

RESULTS

At baseline, patients with RA presented with lower HRV compared to controls during deep breathing (6 breaths/min), paced normal breathing (12 breaths/min) and after passive tilt to the upright position. No significant change in HRV was observed at the five-year follow-up. A significant negative correlation was found between HRV parameters and systolic blood pressure (SBP) at baseline. A significant positive correlation was found between heart rate and inflammatory markers at baseline but not after five years. Nine patients had developed CVD after 11 years, but no significant association was found with baseline HRV data.

CONCLUSION

This study showed that patients with RA have autonomic imbalance both at an early stage of the disease and after five years, despite anti-rheumatic medication, but no correlation between HRV and inflammation markers were observed. Reduced HRV was also significantly negatively correlated with increased SBP. Hypertension is a common finding in patients with RA. Thus, significant decline of HRV could be a useful early marker for development of hypertension in patients with RA.

Accelerated atherosclerosis in rheumatoid arthritis: a systematic review

Background: Rheumatoid arthritis (RA) is a highly prevalent, chronic inflammatory condition of the synovial joints that affects approximately 1% of the global population. The pathogenesis of RA is predominantly inflammatory in nature, thereby accelerating the co-occurrence of other immunoinflammatory conditions such as atherosclerosis. Apart from traditional cardiovascular risk factors, RA patients possess a multitude of other factors that predispose them to early atherosclerotic disease. The aim of this systematic review is to assess the prevalence of premature atherosclerosis in RA patients and elucidate the role that proinflammatory cytokines, RA-related autoantibodies, and endothelial dysfunction play in the pathophysiology of RA-mediated atherosclerosis. We also discussed novel biomarkers that can be used to predict early atherosclerosis in RA and current guidelines used to treat RA. Methods: This review followed the PRISMA guidelines to select and analyze relevant articles. A literature search for articles was performed on February 25, 2022, through three research databases including PubMed, ProQuest, and ScienceDirect. The query used to identify relevant publications was "Rheumatoid arthritis and atherosclerosis" and the search duration was set from 2012-2022. Relevant articles were selected based on the inclusion and exclusion criteria. Results: Our initial search generated 21,235 articles. We narrowed our search according to the inclusion and exclusion criteria. After assessing eligibility based on the full content of the articles, 73 articles were ultimately chosen for this review. Conclusion: There is an increased prevalence of accelerated atherosclerosis among RA patients. We found evidence to explain the role of proinflammatory cytokines, RA-related autoantibodies, and endothelial dysfunction in the pathophysiology RA-mediated atherosclerosis. Therapies targeting either the inflammatory load or traditional CV risk-factors seem to improve vascular outcomes in RA patients. Novel markers of atherosclerosis in RA may be useful in predicting premature atherosclerosis and serve as new targets for therapeutic intervention.

Accelerated atherosclerosis in rheumatoid arthritis: a systematic review

Background: Rheumatoid arthritis (RA) is a highly prevalent, chronic inflammatory condition of the synovial joints that affects approximately 1% of the global population. The pathogenesis of RA is predominantly inflammatory in nature, thereby accelerating the co-occurrence of other immunoinflammatory conditions such as atherosclerosis. Apart from traditional cardiovascular risk factors, RA patients possess a multitude of other factors that predispose them to early atherosclerotic disease. The aim of this systematic review is to assess the prevalence of premature atherosclerosis in RA patients and elucidate the role that proinflammatory cytokines, RA-related autoantibodies, and endothelial dysfunction play in the pathophysiology of RA-mediated atherosclerosis. We also discussed novel biomarkers that can be used to predict early atherosclerosis in RA and current guidelines used to treat RA. Methods: This review followed the PRISMA guidelines to select and analyze relevant articles. A literature search for articles was performed on February 25, 2022, through three research databases including PubMed, ProQuest, and ScienceDirect. The query used to identify relevant publications was "Rheumatoid arthritis and atherosclerosis" and the search duration was set from 2012-2022. Relevant articles were selected based on the inclusion and exclusion criteria. Results: Our initial search generated 21,235 articles. We narrowed our search according to the inclusion and exclusion criteria. After assessing eligibility based on the full content of the articles, 73 articles were ultimately chosen for this review. Conclusion: There is an increased prevalence of accelerated atherosclerosis among RA patients. We found evidence to explain the role of proinflammatory cytokines, RA-related autoantibodies, and endothelial dysfunction in the pathophysiology RA-mediated atherosclerosis. Therapies targeting either the inflammatory load or traditional CV risk-factors seem to improve vascular outcomes in RA patients. Novel markers of atherosclerosis in RA may be useful in predicting premature atherosclerosis and serve as new targets for therapeutic intervention.

Lipoprotein-associated phospholipase A2 and carotid intima-media thickness in primary Sjögren syndrome

Objectives: This study aims to evaluate serum lipoprotein-associated phospholipase A2 (Lp-PLA2) level and carotid intima-media thickness in primary Sjögren syndrome (pSS) as an indicator of atherosclerosis.

Patients and methods: Between July 2019 and July 2020, a total of 33 female pSS patients (mean age: 44.5±11.2 years; range, 23 to 60 years) and 37 female age- and sex-matched healthy individuals (mean age: 40.9±7.2 years; range, 25 to 54 years) were included. Carotid intima-media thickness and serum Lp-PLA2 levels were measured in the patient and control groups.

Results: The patients had a higher median serum Lp-PLA2 of 560 (range, 108 to 1,222) ng/mL vs. 328 (range, 0 to 1,280) ng/mL in the controls (p=0.024) and a similar mean intima-media thickness of carotid artery (0.64±0.14 mm vs. 0.62±0.15 mm, respectively; p=0.595). Serum Lp-PLA2 was positively correlated with platelet count (r=0.411, p=0.018) and negatively correlated with erythrocyte sedimentation rate (r=-0.409, p=0.018). The mean value of carotid intima-media thickness was positively correlated with disease duration (r=0.316, p=0.074) and was negatively correlated with the level of leucocyte (r=-0.458, p=0.007).

Conclusion: Our study suggests that the patients of pSS have a potential risk of atherosclerotic cardiovascular disease, independent of traditional cardiovascular risk factors and disease severity.

Recognized and Potentially New Biomarkers-Their Role in Diagnosis and Prognosis of Cardiovascular Disease

Atherosclerosis and its consequences are the leading cause of mortality in the world. For this reason, we have reviewed atherosclerosis biomarkers and selected the most promising ones for review. We focused mainly on biomarkers related to inflammation and oxidative stress, such as the highly sensitive C-reactive protein (hs-CRP), interleukin 6 (IL-6), and lipoprotein-associated phospholipase A2 (Lp-PLA2). The microRNA (miRNA) and the usefulness of the bone mineralization, glucose, and lipid metabolism marker osteocalcin (OC) were also reviewed. The last biomarker we considered was angiogenin (ANG). Our review shows that due to the multifactorial nature of atherosclerosis, no single marker is known so far, the determination of which would unambiguously assess the severity of atherosclerosis and help without any doubt in the prognosis of cardiovascular risk.

Research Progress of Therapeutic Enzymes and Their Derivatives: Based on Herbal Medicinal Products in Rheumatoid Arthritis

Rheumatoid arthritis (RA) acts as one of the most common, agnogenic and chronic inflammatory-autoimmune disorder which is characterized by persistent synovitis, cartilage destruction, and joint deformities, leads to a wide range of disabilities, and increased mortality, thus imposing enormous burdens. Several drugs with anti-inflammatory and immunomodulatory properties such as celecoxib, diclofenac and methotrexate are being selected as conventional drugs in the allopathic system of medicine for the treatment of RA in clinic. However, there are some serious side effects more or less when using these drugs because of their short poor bioavailability and biological half-life for a long time. These shortcomings greatly promote the exploration and application of new low- or no-toxicity drugs for treating the RA. Meanwhile, a growing number of studies demonstrate that several herbs present certain anti-inflammatory and anti-arthritic activities through different enzymes and their derivatives, which indicate that they are promising therapeutic strategies when targeting these mediators based on herbal medicinal products in RA research. This review article summarizes the roles of the main enzymes and their derivatives during the pathogenesis of RA, and clearly clarifies the explicit and potential targeted actions of herbal medicinal products that have anti-RA activity. Our review provides timely and critical reference for the scientific rationale use of herbal medicinal products, with the increasing basic research and clinical application of herbal medicinal products by patients with RA.

Biomarkers associated with cardiovascular disease in patients with early rheumatoid arthritis

Objectives

Patients with rheumatoid arthritis (RA) have an increased mortality and morbidity due to cardiovascular disease (CVD). In this prospective 5-year follow up of patients with RA, we analysed several biomarkers, known to be associated with atherosclerosis and/or inflammation in the general population. The aim of this study was to find out whether the RA-disease per se affect these biomarkers and if those could be associated with the progression of atherosclerosis, as measured by intima media thickness (IMT) among patients with early RA.

Methods

Patients from northern Sweden diagnosed with early RA, are consecutively recruited into an ongoing prospective study on CVD comorbidity. A subgroup of patients, aged ≤60 years (n = 71) was included for ultrasound measurements of IMT at inclusion (T0) and after 5 years (T5) together with age-sex-matched controls (n = 40). The patients were clinically assessed. Blood was analysed for lipids, ESR and CRP and several biomarkers known to be associated with atherosclerosis in the general population.

Results

At T0, the patients with RA had significantly lower levels of MIF and significantly higher levels of interleukin (IL)-18 and MIC-1 compared with controls. At T5, the patients with RA had significantly higher levels of pentraxin3, MIC-1, TNF-R2, ICAM-1, VCAM-1 and endostatin compared with controls. At T0 the levels of MPO correlated with DAS28, sCD40L with CRP and IL-18 with systolic blood pressure and Reynolds risk score. Using PLSR on a CVD-panel analysed with multiplex immunoassay, the patients with RA could be correctly classified into those who had a worsening in their IMT over the five years or not. Here, MMP3 was identified as influential.

Conclusions

This study indicates that the RA disease itself could affect several of the biomarkers in this study, and possibly also the processes involved in the development of atherosclerosis.

Lipoprotein-associated phospholipase A2: The story continues

Inflammation is thought to play an important role in the pathogenesis of vascular diseases. Lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates vascular inflammation through the regulation of lipid metabolism in blood, thus, it has been extensively investigated to identify its role in vascular inflammation-related diseases, mainly atherosclerosis. Although darapladib, the most advanced Lp-PLA2 inhibitor, failed to meet the primary endpoints of two large phase III trials in atherosclerosis patients cotreated with standard medical care, the research on Lp-PLA2 has not been terminated. Novel pathogenic, epidemiologic, genetic, and crystallographic studies regarding Lp-PLA2 have been reported recently, while novel inhibitors were identified through a fragment-based lead discovery strategy. More strikingly, recent clinical and preclinical studies revealed that Lp-PLA2 inhibition showed promising therapeutic effects in diabetic macular edema and Alzheimer's disease. In this review, we not only summarized the knowledge of Lp-PLA2 established in the past decades but also emphasized new findings in recent years. We hope this review could be valuable for helping researchers acquire a much deeper insight into the nature of Lp-PLA2, identify more potent and selective Lp-PLA2 inhibitors, and discover the potential indications of Lp-PLA2 inhibitors.

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.

High Concentrations of Angiopoietin-Like Protein 4 Detected in Serum from Patients with Rheumatoid Arthritis Can Be Explained by Non-Specific Antibody Reactivity

Angiopoietin-like protein 4 (ANGPTL4) is suggested to be a master regulator of plasma triglyceride metabolism. Our aim was to study whether the previously reported high levels of ANGPTL4 detected in serum from patients with rheumatoid arthritis (RA) by ELISA was due to any specific molecular form of this protein (oligomers, monomers or fragments). ANGPTL4 levels were first determined in serum from 68 RA patients and 43 age and sex matched control subjects and the mean values differed by a factor of 5.0. Then, ANGPTL4 was analyzed after size exclusion chromatography (SEC) of serum samples. With serum from one of the RA patients with high levels of ANGPTL4, the dominant reactivity was found in fractions corresponding to high-molecular weight proteins. In addition, a minor peak of reactivity eluting late from the column was found both in the patient and in controls. By the use of HeteroBlock®, and by careful selection of antibodies, we documented non-specific reactions for ANGPTL4 in 39% of samples from the RA patients, most likely due to cross-reactivity of the antibodies with rheumatoid factor (RF). The corresponding figure for control subjects was 6.3%. After corrections for non-specific reactions, the mean level of ANGPTL4 in serum from RA patients was still significantly higher than in control individuals (mean levels were 101±62 and 67±39 ng/ml respectively, P = 0.02). We re-analyzed samples from our previously published studies on ANGPL4 levels in patients on hemodialysis and patients with diabetes type 2. These samples did not show false positive reactions. The levels of ANGPTL4 were comparable to those detected previously.