Association of serum lipids with autoantibodies and inflammatory markers in rheumatoid arthritis patients

Association of ultraprocessed food consumption with risk of rheumatoid arthritis: a retrospective cohort study in the UK Biobank

BACKGROUND

Limited studies explored the association between consumption of ultraprocessed food (UPF) and rheumatoid arthritis (RA).

OBJECTIVES

This study aimed to examine the association between UPF consumption and RA risk and explore the potential mediating effects of RA-related biomarkers.

METHODS

This retrospective cohort study included 207,012 participants without RA at recruitment and completed 24-h dietary recalls. UPF was defined based on the NOVA food classification system. Incident RA was ascertained using the International Classification of Diseases version 10. Cox regression models were used to examine the association between UPF consumption and the incidence of RA. Additionally, mediation analyses were conducted to evaluate the contribution of biomarkers related to the lipid profile, systemic inflammatory factors, serum liver enzymes, and glucose metabolism to the observed associations.

RESULTS

The participants' mean (standard deviation [SD]) age at recruitment was 56.08 (7.95) y. During a median follow-up of 12.24 (interquartile range: 11.66-13.03) y, 1869 RA events were recorded. Compared with the lowest quintile of UPF consumption (weight percentage of the UPF), the adjusted hazard ratio (HR) of RA in the highest quintile was 1.17 (95% confidence interval (CI): 1.01, 1.36). There was a 6% elevated risk of RA incidence per SD increase in UPF intake (HR: 1.06; 95% CI: 1.01, 1.11). In the mediation analyses, the biomarkers explained 3.07%-14.80% of the association between UPF intake and RA.

CONCLUSIONS

Higher UPF consumption was associated with an increased risk of RA, which may be mediated by inflammation, lipids, and liver enzymes. Lower UPF consumption is recommended to reduce RA incidence.

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.

The Sizes and Composition of HDL-Cholesterol Are Significantly Associated with Inflammation in Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA), a chronic inflammatory disease, carries a significant burden of atherosclerotic cardiovascular diseases (ASCVD). With their heterogeneous composition, high-density lipoprotein (HDL) particles have varied athero-protective properties, and some may even increase ASCVD risk. In this prospective and cross-sectional study, we aimed to examine the relationship between HDL sizes/metabolites and inflammation in RA. Using ¹H-NMR-based lipid/metabolomics, differential HDL-related metabolites were identified between RA patients and healthy control (HC) subjects and between RA patients with and without anti-citrullinated peptide antibodies (ACPA). The correlation between the discriminative HDL-related metabolites and C-reactive protein (CRP) was evaluated in RA patients. RA patients demonstrated higher particle number, lipids, cholesterol, cholesterol ester, free cholesterol, and phospholipids in large/very large-sized HDLs. ACPA-positive patients had higher L-HDL-C and L-HDL-CE but lower small-/medium-sized HDL-TG levels than ACPA-negative patients. An inverse correlation was found between CRP levels and small-sized HDLs. Janus kinase inhibitor treatment was associated with increased serum small-sized HDL-related metabolites and decreased CRP levels. We are the first to reveal the significant associations between RA inflammation and HDL sizes/metabolites. A potential link between ACPA positivity and changes in serum levels of HDL-related metabolites was also observed in RA patients.

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.

Inflammatory markers in rheumatic diseases

Immune-mediated rheumatic diseases (IMRDs) are a broad group of pathological conditions based on impaired immunological tolerance to one’s own tissues leading to inflammation and irreversible organ damage. Laboratory diagnosis of IMRDs includes a wide range of biomarkers (autoantibodies, acute phase proteins, cytokines, markers of endothelial damage, components of the complement system, immunoglobulins, cryoglobulins, lymphocyte subpopulations, indicators of bone metabolism, apoptosis markers, genetic markers, etc). One of the leading aspects of laboratory diagnosis of IMRDs is the study of the level of inflammation markers in the blood (erythrocyte sedimentation rate, C-reactive protein (CRP), serum amyloid protein (CAA), ferritin, procalcitonin, apolipoprotein AI, calprotectin, etc). The analysis of inflammation markers makes it possible to assess the disease activity, the nature of the progression and the prognosis of the outcomes of a chronic inflammatory process, as well as the effectiveness of the therapy. The review presents the latest data on the role of the most frequently studied inflammatory markers such as CRP, CAA and ferritin.

Low high-density lipoprotein cholesterol and apolipoprotein A-I levels are associated with poor outcome and relapse in autoimmune encephalitis

BACKGROUND

Growing evidence suggests an association between dyslipidemia and autoimmune diseases. This study aimed to investigate the relationship between lipid profiles and prognosis of autoimmune encephalitis (AE) patients.

METHODS

This retrospective study consisted of 114 AE patients from September 2014 to September 2020. Data of clinical parameters, including age, sex, body mass index (BMI), clinical features, comorbidities, therapeutic management, lipid profiles, modified Rankin scale (mRS) scores, outcomes, and relapses were collected. Logistic regression models were used to examine the associations between lipid profiles and outcomes of AE. Correlations between lipid profiles and C-reactive protein (CRP), which is an inflammatory marker, were assessed.

RESULTS

In the univariate logistic analysis, sex (P = 0.030), mental behavior disorder (P = 0.004), disturbance of consciousness (P = 0.002), mRS at study entry (P = 0.020), tumor comorbidity (P = 0.028), high-density lipoprotein cholesterol (HDL-C) (P = 0.029), apolipoprotein A-I (apoA-I) (P = 0.012), apolipoprotein B (apoB) (P = 0.036) and apoA-I/apoB (P = 0.001) levels were all associated with the unfavorable outcomes of patients. After adjustment for age, sex and mRS at study entry, lower apoA-I and apoA-I /apoB levels were still significantly associated with the unfavorable outcomes of patients. Low HDL-C (P = 0.048) and apoA-I levels (P = 0.026) were also significantly associated with the relapse of AE patients. HDL-C and apoA-I levels were negatively correlated with CRP levels in correlation analysis.

CONCLUSIONS

Lipid profiles, especially low HDL-C and apoA-I levels, are significantly associated with the poor outcomes and relapse of AE patients, and seem associated with inflammatory responses. HDL-C and apoA-I levels may be good candidates for predicting prognosis of AE patients.

Triggers of Cardiovascular Diseases in Rheumatoid Arthritis

The risk of cardiovascular disease (CVD) in patients with rheumatoid arthritis (RA) is higher than that in patients without RA, and it is even higher than that in patients with diabetes. Autoimmune-mediated inflammation is observed in patients with RA, resulting in endothelial dysfunction, oxidative stress and activation, and vascular migration of white blood cells. Traditionally, RA-associated CVD was assumed to be mediated by disease-related inflammation, resulting in atherosclerosis (AS). However, this concept has been challenged because treatment with anti-rheumatic drugs, such as methotrexate or proinflammatory cytokine antagonists, such as tumor necrosis factor-alpha (TNF-α) inhibitors, did not reduce the risk of CVD in patients with RA. Current cardiovascular guidelines recommend screening and treatment of CVD risk factors in patients with RA but without clear biomarkers and treatment goals. There is no scientific basis for establishing therapeutic targets for cardiovascular risk factors in RA. Numerous studies have shown that the mechanism of early cardiac dysfunction in patients with RA may occur prior to AS. Therefore, it is crucial to explore the related mechanisms to prevent early cardiac dysfunction in patients with RA.

C-reactive protein and implications in rheumatoid arthritis and associated comorbidities

C-reactive protein (CRP) is routinely assessed as a marker of systemic inflammation in rheumatoid arthritis (RA). However, it is also an immune regulator that plays an important role in inflammatory pathways associated with RA and promotes atherogenic effects. Comorbidities linked to systemic inflammation are common in RA, and CRP has been associated with the risk for cardiovascular disease, diabetes, metabolic syndrome, pulmonary diseases, and depression. The relationship between systemic inflammation, CRP, and comorbidities in RA is complex, and it is challenging to determine how changing CRP levels may affect the risk or progression of these comorbidities. We review the biological role of CRP in RA and its implications for disease activity and treatment response. We also discuss the impact of treatment on CRP levels and whether reducing systemic inflammation and inhibiting CRP-mediated inflammatory pathways may have an impact on conditions commonly comorbid with RA.

Vitamin D status affects the relationship between lipid profile and high-sensitivity C-reactive protein

Background

The biological pathways through which vitamin D is involved in the regulation of systemic inflammation remain largely unknown.

Objective

The objective of this study was to evaluate the role of vitamin D status on the relationship between lipid profile and high-sensitivity C-reactive protein (hs-CRP) in pregnant women.

Design

Serum 25-hydroxyvitamin D (25(OH)D), hs-CRP, and indicators of lipid profiles (total cholesterol, TC; triglyceride, TG; high-density lipoprotein cholesterol, HDL-C; low-density lipoprotein cholesterol, LDL-C), were measured in 2479 pregnant women during the second trimester. Potential confounding including maternal sociodemographic characteristics, perinatal health status, diet, and lifestyle was prospectively collected. Multiple regression models and cubic models were used to evaluate the associations.

Results

There was a significant non-linear relationship between lipid profile (TC, TG, HDL-C, LDL-C) and hs-CRP (P < 0.05). Increased serum 25(OH)D was significantly associated with decreasing TC, TG, HDL-C, LDL-C, and hs-CRP levels. Compared with medium levels of lipids group, pregnant women with higher levels of TC or TG have higher levels of hs-CRP, and pregnant women with lower levels of TC, HDL-C or LDL-C also have higher levels of hs-CRP in the vitamin D deficient group, and there was a significant correlation between low levels of TG and decreased hs-CRP (adjusted β for TG: -0.063, 95%CI: − 0.120,-0.007) in the non-vitamin D deficient group. Mediators that had appreciable shares of the associations between 25(OH)D and hs-CRP was TG (10.2% of the association; β = − 0.011; total indirect effect: 95% CI: − 0.019, − 0.002). The cubic model suggested that a steep increase in the adjusted regression coefficient of lipid with hs-CRP up to 50 nmol/L of 25(OH)D, and the highest adjusted regression coefficients were observed in pregnant women with 25(OH)D above 50 nmol/L.

Conclusion

Our findings suggest that high levels of vitamin D during pregnancy may improve lipid profile levels and inhibit elevated hs-CRP induced by high lipid metabolism.