Correlation Between Total Bilirubin, Total Bilirubin/Albumin Ratio with Disease Activity in Patients with Rheumatoid Arthritis

The role of bilirubin as a biomarker of rheumatic diseases: a systematic review and meta-analysis

The identification of novel, yet easily measurable biomarkers of inflammation and oxidative stress might assist in the diagnosis and management of patients with rheumatic diseases (RDs). We conducted a systematic review and meta-analysis of studies investigating the circulating concentrations of bilirubin, the end product of heme metabolism and a potent endogenous antioxidant with anti-inflammatory properties, in patients with RDs and healthy controls. The electronic databases PubMed, Scopus, and Web of Science were searched from inception to 31 December 2023 for relevant articles. We evaluated the risk of bias and the certainty of evidence using the Joanna Briggs Checklist and the Grades of Recommendation, Assessment, Development, and Evaluation Working Group system, respectively. In 17 eligible studies, all with low risk of bias, compared to controls, patients with RDs had significantly lower concentrations of total bilirubin (standard mean difference, SMD=-0.68, 95% CI -0.91 to -0.44, p<0.001; I2 = 92.5%, p<0.001; low certainty of evidence), direct (conjugated) bilirubin (SMD=-0.67, 95% CI -0.92 to -0.41, p<0.001; I2 = 81.7%, p<0.001; very low certainty of evidence), and the active antioxidant and anti-inflammatory indirect (unconjugated) form of bilirubin (SMD=-0.71, 95% CI -1.18 to -0.24, p=0.003; I2 = 95.1%, p<0.001; very low certainty of evidence). The results of the meta-analysis were stable in sensitivity analysis. In meta-regression, there were no significant associations between the SMD of total bilirubin and several clinical and demographic characteristics, including age, male to female ratio, number of participants, liver enzymes and erythrocyte sedimentation rate. In subgroup analysis, the SMD of total bilirubin was significant across a range of RDs, including rheumatoid arthritis, systemic lupus erythematosus, primary Sjögren syndrome, and myositis. Therefore, the results of our systematic review and meta-analysis suggests that the reductions in bilirubin concentrations observed in patients with RDs reflect a state of impaired antioxidant and anti-inflammatory defence due to bilirubin consumption and highlight the promising role of this endogenous product as a biomarker of RDs.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023500649.

Evaluation of the prognostic nutritional index (PNI) as a tool for assessing disease activity in rheumatoid arthritis patients

OBJECTIVES

Rheumatoid arthritis (RA) is an autoimmune disease of unknown exact cause, characterized by chronic inflammation. The prognostic nutritional index (PNI), reflecting albumin concentration and lymphocyte count, is a newly established inflammation-based nutritional score. This study aimed to determine the relationship between PNI and disease activity in RA patients.

PATIENTS AND METHODS

This cross-sectional study included 138 RA patients who met the 2010 revised criteria of the American College of Rheumatology (ACR) for RA. PNI was calculated using the following formula: 10 × serum albumin value (g/dL) + 0.005 × total lymphocyte count in the peripheral blood (per mm3). The study population was divided into two groups: DAS28-ESR ≤ 3.2 (group 1 with remission and low disease activity) and DAS28-ESR > 3.2 (group 2 with moderate and high disease activity).

RESULTS

A total of 138 patients with a mean age of 52.1 years were recruited. While the female gender was more prevalent in both groups, it was significantly higher in group 2 (p < 0.05). Group 2 exhibited a lower PNI compared to those in group 1 (42.17 ± 3.46 vs. 44.02 ± 2.92; p = 0.001). Multivariate logistic regression analyses revealed that PNI was an independent predictor of disease activity (OR, 0.850; 95% CI, 0.735-0.983; p = 0.029). ROC curve analysis determined that the optimal cutoff value of PNI for disease activity was 43.01, with a sensitivity of 69.1% and specificity of 57.7% (AUC, 0.66; 95% CI, 0.57-0.75, p = 0.001).

CONCLUSION

This study demonstrates that the simple and readily available PNI could serve as an independent predictor of disease activity in rheumatoid arthritis patients. Key Points •The relationship between disease activity and the prognostic nutritional index, which is a nutritional indicator, in rheumatoid arthritis patients was investigated. •It has been shown that there is a connection between low PNI and high disease activity. •It has been shown that PNI can be used to evaluate disease severity with a simple calculation.

Exploring the effect of LncRNA DANCR to regulate the Keap1-Nrf2/ARE pathway on oxidative stress in rheumatoid arthritis

INTRODUCTION

Aberrant expression of long noncoding RNAs (LncRNAs) can regulate oxidative stress in rheumatoid arthritis (RA). This study focused on investigating the effects of LncRNA differentiation antagonizing nonprotein coding RNA (DANCR) regulation of Keap1-Nrf2/ARE pathway on inflammation and oxidative stress in RA.

METHODS

The levels of LncRNA DANCR/miR-486-3p/Keap1 in peripheral blood of 30 RA groups and 30 normal subjects were examined, and the association of LncRNA DANCR with inflammatory indicators of RA was investigated. We stimulated fibroblast-like synoviocytes (FLS) from RA patients with tumor necrosis factor α and subsequently performed in vitro cellular assays to construct overexpression plasmids and small interfering RNAs of LncRNA DANCR to investigate the relationship between LncRNA DANCR and FLSs viability and migration in RA, as well as the effects on cellular oxidative stress factors and Keap1-Nrf2/ARE pathway; molecular biology analysis was used to predict microRNAs that can bind LncRNA DANCR, and luciferase verified the binding sites of LncRNA DANCR with Keap1 and miR-486-3p; to further refine the gene and protein expression results, we used reverse transcription-quantitative polymerase chain reaction and immunoblotting assays.

RESULTS

In both groups of peripheral blood mononuclear cells, the expression levels of LncRNA DANCR and Keap1 messenger RNA were higher in the RA group than in the normal control group, and the opposite was true for miR-486-3p; LncRNA DANCR was positively correlated with total antioxidant capacity (TAOC), IL6, IL17, malondialdehyde (MDA), but not with IL11, rheumatoid factor, cyclic citrullinated peptide, superoxide dismutase (SOD), with 28-joint disease activity score, reactive oxygen species, C-reactive protein, and erythrocyte sedimentation rate were negatively correlated; overexpression of LncRNA DANCR stimulated the Keap1-Nrf2/ARE pathway, decreased the expression of IL10, SOD, TAOC, and increased the expression levels of MDA, IL11, IL-17, PD-L1, and silencing of LncRNA DANCR was the opposite, but knockdown of miR-486-3p or overexpression of keap1 reversed the expression of the above-mentioned inflammatory and oxidative factors. In addition, pcDNA-DANCR clearly showed stronger cell invasion and migration ability and exacerbated its inflammatory response, which may be related to the regulatory role of miR-486-3p and Keap1-Nrf2/ARE signaling pathway, and we verified their targeting relationship using dual luciferase, showing that DANCR could regulate Keap1-Nrf2/ARE through miR-486-3p modulates the Keap1-Nrf2/ARE pathway and affects inflammatory and oxidative responses in RA patients.

CONCLUSION

The low-expressed LncRNA DANCR may regulate the Keap1-Nrf2/ARE pathway and suppress the inflammatory and oxidative responses in RA patients.

Metabolic Effects of Anti-TNF-α Treatment in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is associated with high cardiovascular mortality. It is not clear whether the metabolic consequences of chronic inflammation are involved. Biological disease-modifying anti-rheumatic drugs (bDMARDs) are highly efficient in the treatment of inflammation in RA. In this study, we aimed to describe the metabolic effects of anti-TNF-α treatment in RA patients. The clinical status of 16 patients was assessed using disease activity score-28 (DAS28) and C-reactive protein (CRP). Plasma samples were collected before treatment with anti-TNF-α treatment as well as after three and six months of treatment. Markers of lipid and glucose metabolism, as well as renal biomarkers, were assessed using standard biochemistry. ELISA was used for the quantification of insulin, leptin, and adiponectin. Although fasting insulin decreased by 14% at the end of the study, most of the analyzed parameters did not show any statistically or clinically significant dynamics. The exception was total bilirubin and cholesterol, which increased by 53% and 14%, respectively, after six months of treatment with anti-TNF-α treatment. Anti-TNF-α treatment did not induce major metabolic changes despite the strong anti-inflammatory and clinical symptoms of RA. Further studies will show whether longer observations are required for the detection of the metabolic effects of the anti-inflammatory treatment. Additional research is needed to understand the observed effect of bilirubin as an important endogenous antioxidant.