A Systematic Review and Meta-Analysis of the Association between Uric Acid and Allantoin and Rheumatoid Arthritis

Alterations in the circulating concentrations of uric acid and its degradation product, allantoin, might account for the systemic pro-oxidant state and the increased cardiovascular risk in rheumatoid arthritis (RA). We sought to address this issue by conducting a systematic review and meta-analysis of the association between the plasma/serum concentrations of uric acid and allantoin and RA. We searched PubMed, Scopus, and Web of Science from inception to 20 June 2023 for studies comparing plasma/serum concentrations of uric acid and allantoin between RA patients and healthy controls. We assessed the risk of bias with the JBI Critical Appraisal Checklist for analytical studies and the certainty of evidence with the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) Working Group system. In the 19 studies selected for analysis, there were non-significant differences in uric acid concentrations between RA patients and controls (standard mean difference, SMD = 0.11, 95% CI -0.07 to 0.30, p = 0.22; I2 = 87.9%, p < 0.001; low certainty of evidence). By contrast, the concentrations of allantoin were significantly higher in RA patients (SMD = 1.10, 95% CI 0.66 to 1.55, p < 0.001; I2 = 55.6%, p = 0.08; extremely low certainty of evidence). In meta-regression, a significant association was observed between the SMD of uric acid concentrations and body mass index, a risk factor for atherosclerosis and cardiovascular disease (t = 3.35, p = 0.007). Our study has shown a significant increase in the concentrations of the oxidative stress biomarker allantoin in patients with RA. Further research is warranted to investigate the interplay between uric acid, allantoin, redox balance, and cardiovascular disease in this group. (PROSPERO registration number: CRD42023441127).

Impact of Cadmium Mediated by Tobacco Use in Musculoskeletal Diseases

Tobacco use has a negative impact on health due to its relationship with the development of high-mortality diseases, such as pulmonary cancer. However, the effect of cadmium (Cd), present in tobacco smoke, on the development of joint diseases has been scarcely studied. The objective of this review is to discuss the evidence regarding the mechanisms by which Cd exposure, through tobacco smoke, may lead to the development of osteoarthritis (OA), osteoporosis (OP), and rheumatoid arthritis (RA). There's evidence suggesting a string association between moderate to severe OA development and tobacco use, and that a higher blood concentration of Cd can trigger oxidative stress (OS) and inflammation, favoring cartilage loss. At the bone level, the Cd that is inhaled through tobacco smoke affects bone mineral density, resulting in OP mediated by a decrease in the antioxidant enzymes, which favors the bone resorption process. In RA, tobacco use promotes the citrullination process through Cd exposure and increases OS and inflammation. Understanding how tobacco use can increase the damage at the articular level mediated by a toxic metal, i.e., Cd, is important. Finally, we propose prevention, control, and treatment strategies for frequently disabling diseases, such as OA, OP, and RA to reduce its prevalence in the population.

Linkage of Periodontitis and Rheumatoid Arthritis: Current Evidence and Potential Biological Interactions

The association between rheumatoid arthritis (RA) and periodontal disease (PD) has been the focus of numerous investigations driven by their common pathological features. RA is an autoimmune disease characterized by chronic inflammation, the production of anti-citrullinated proteins antibodies (ACPA) leading to synovial joint inflammation and destruction. PD is a chronic inflammatory condition associated with a dysbiotic microbial biofilm affecting the supporting tissues around the teeth leading to the destruction of mineralized and non-mineralized connective tissues. Chronic inflammation associated with both RA and PD is similar in the predominant adaptive immune phenotype, in the imbalance between pro- and anti-inflammatory cytokines and in the role of smoking and genetic background as risk factors. Structural damage that occurs in consequence of chronic inflammation is the ultimate cause of loss of function and disability observed with the progression of RA and PD. Interestingly, the periodontal pathogen Porphyromonas gingivalis has been implicated in the generation of ACPA in RA patients, suggesting a direct biological intersection between PD and RA. However, more studies are warranted to confirm this link, elucidate potential mechanisms involved, and ascertain temporal associations between RA and PD. This review is mainly focused on recent clinical and translational research intends to discuss and provide an overview of the relationship between RA and PD, exploring the similarities in the immune-pathological aspects and the possible mechanisms linking the development and progression of both diseases. In addition, the current available treatments targeting both RA and PD were revised.

Selenium Nanoparticles Dispersed in Phytochemical Exert Anti-Inflammatory Activity by Modulating Catalase, GPx1, and COX-2 Gene Expression in a Rheumatoid Arthritis Rat Model

BACKGROUND Literature shows that serum selenium concentration is low in rheumatoid arthritis (RA) patients. Biochemical properties of nanoparticles (NPs) are depend in its medium dispersed. Biochemical properties could effectively alter the therapeutic potential of NPs. Phytochemicals could serve as suitable medium for dispersion of NPs. P-Coumaric acid (CA) known to have anti-inflammatory activity. MATERIAL AND METHODS In the present experiment, we investigated the anti-inflammatory effect of SeNPs dispersed in 1% CA against Complete Freund's adjuvant induced RA. Celecoxib was used as a reference drug. RESULTS Selenium NPs (SeNPs) size is maintained in 1% CA solution. We observed that supplementation with 500 μg/Kg body weight (b.w.) eNPs significantly restored the levels of thiobarbituric acid reactive substances, COX-2 activity, different antioxidant enzyme activities, and inflammatory cytokines (TNF-α, IL-1β, IL-6, and MCP-1) in RA rats. The mRNA expression of antioxidant enzymes such as MnSOD, Cu/ZnSOD, ECSOD, CAT, and GPx1 was found to be downregulated, whereas COX-2 was upregulated in RA rats; however, the mRNA expression of CAT, GPx1, and COX-2 reverted back to near normal levels in SeNPs-treated animals. CONCLUSIONS The therapeutic potential of SeNPs was confirmed through histological observation of angle joints in different experimental animals. Our results collectively suggest that SeNPs dispersed in CA can be an effective therapeutic agent for inflammatory disorders like acute gouty arthritis.

Salicin from Alangium chinense Ameliorates Rheumatoid Arthritis by Modulating the Nrf2-HO-1-ROS Pathways

Rheumatoid arthritis (RA) is a chronic inflammatory disorder linked to oxidative stress of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). The effects and potential mechanism of salicin on inflammation and oxidative stress of RA-FLSs were examined by MTT, ELISA, and Western blot methods. Salicin significantly reduced cell viability (82.03 ± 7.06, P < 0.01), cytokines (47.70 ± 1.48 ng/L for TNF-α, 30.03 ± 3.49 ng/L for IL-6) ( P < 0.01), and matrix metalloproteinases-1/-3 expression ( P < 0.01) in IL-1β-induced RA-FLSs and inhibited ROS generation and p65 phosphorylation ( P < 0.01) as compared with IL-1β-induced treatment. Moreover, salicin promoted Nrf2 nuclear translocation (2.15 ± 0.21) and HO-1 expression (1.12 ± 0.05) and reduced ROS production in IL-1β-induced RA-FLSs ( P < 0.01). Salicin not only reduced the collagen-induced arthritis by reducing the clinical score ( P < 0.01), inflammatory infiltration, and synovial hyperplasia in vivo but also suppressed the oxidative damage indexes (SOD 155.40 ± 6.53 U/mg tissue, MDA 152.80 ± 5.89 nmol/g tissue, GSH 50.98 ± 3.45 nmol/g tissue, and CAT 0.92 ± 0.10 U/g protein) ( P < 0.01) of ankle joint cells. Conclusively, our findings indicate that salicin ameliorates rheumatoid arthritis, which may be associated with oxidative stress and Nrf2-HO-1-ROS pathways in RA-FLSs.

Carnosic acid (CA) attenuates collagen-induced arthritis in db/db mice via inflammation suppression by regulating ROS-dependent p38 pathway

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease, characterized by inflammation of synovial joints. Carnosic acid (CA) is a phenolic diterpene isolated from Rosmarinus officinailis, playing a central role in cytoprotective responses to oxidative stress and inflammation response. Our study aimed to investigate the effects of CA on RA progression in diabetic animals. Carnosic acid (CA) was used to treat collagen-induced arthritis (CIA)-induced db/db mice. Blood glucose, oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were investigated to explore insulin resistance. CA significantly down-regulated fasting blood glucose, glucose level in OGTT and ITT, ameliorated CIA-induced bone loss, and reduced pro-inflammatory cytokines and reactive oxygen species (ROS) in db/db mice with arthritis induced by CIA. In vitro, CA suppressed Receptor Activator for Nuclear Factor-κ B Ligand (RANKL)- and Macrophage colony-stimulating factor (M-CSF)-induced osteoclastogenesis. The osteoclastic specific markers were inhibited by CA. Signal transduction studies showed that CA significantly decreased the expression of molecules contributing to ROS and increased anti-oxidants. Additionally, CA inactivated the RANKL- and M-CSF-induced p38 mitogen activated protein kinases (MAPK), inhibited NF-κB phosphorylation, causing pro-inflammatory cytokines down-regulation. Together, CA ameliorated osteoclast formation and CIA-induced bone loss in db/db mice through inflammation suppression by regulating ROS-dependent p38 pathway.

Ultra‑performance liquid chromatography coupled with quadrupole time‑of‑flight mass spectrometry‑based metabolic profiling of human serum prior to and following radical resection of colorectal carcinoma

Nearly one quarter of patients with colorectal carcinoma (CRC) were diagnosed at an advanced stage. Under these circumstances, radical resection of the tumor is the best strategy to enhance the five-year survival rate. However, up to 50% of post-operative patients experience cancer recurrence within the first few years. Therefore, post‑operative surveillance is important. However, currently performed post‑operative monitoring relies on relatively dated methods with insufficient sensitivity and specificity. The present study applied an advanced technology of ultra‑performance liquid chromatography coupled with quadrupole time‑of‑flight mass spectrometry in order to examine changes in metabolite patterns in serum with the aim of identifying reliable biomarkers in patients with CRC at various time-points. Serum samples were collected from and 20 CRC patients prior to radical resection (group 1) and one month following radical resection (group 2) as well as from 20 healthy volunteers (group 3). Multivariate pattern recognition was used to identify potential biomarkers of CRC. Compared with healthy volunteers, three groups of biomarkers were identified in patients with CRC (P<0.05), namely phosphatidylcholines (PCs), lysophosphatidylcholines (LPCs) and diacylglycerols (DAGs). However, no statistical difference in the levels of these biomarkers between pre‑operative and post‑operative CRC patients was identified (P>0.05). PCs and LPCs, which contain polyunsaturated fatty acids, were decreased, whereas LPCs and DAGs, which contain saturated fatty acids, were increased in CRC patients. The present study demonstrated that obvious metabolic disturbances occur during the development of CRC and provided a novel analytic method, which is likely to be used as a diagnostic tool for CRC and may help to improve the patients' prognosis.

Cigarette smoking and risk of rheumatoid arthritis: a dose-response meta-analysis

Introduction

Although previous studies found that cigarette smoking is associated with risk of rheumatoid arthritis (RA), the dose-response relationship remains unclear. This meta-analysis quantitatively summarizes accumulated evidence regarding the association of lifelong exposure to cigarette smoking assessed as pack-years with the risk of RA.

Methods

Relevant studies were identified by a search of MEDLINE and EMBASE from 1966 to October 2013, with no restrictions. Reference lists from retrieved articles were also reviewed. Studies that reported relative risks (RR) or odds ratio (OR) estimates with 95% confidence intervals (CIs) for the association between pack-years of cigarette smoking and rheumatoid arthritis were included in a dose-response random-effects meta-regression analysis.

Results

We included 3 prospective cohorts and 7 case-control studies in the meta-analysis. They included a total of 4,552 RA cases. There was no indication of heterogeneity (P_{heterogeneity} = 0.32) and publication bias did not affect the results. Compared to never smokers, the risk of developing RA increased by 26% (RR = 1.26, 95% CI 1.14 to 1.39) among those who smoked 1 to 10 pack-years and doubled among those with more than 20 pack-years (RR for 21 to 30 pack years = 1.94, 95% CI 1.65 to 2.27). The risk of RA was not increasing further for higher exposure levels (RR for >40 pack-years = 2.07, 95% CI 1.15 to 3.73). The risk of RA was statistically significantly higher among rheumatoid factor (RF)-positive RA cases (RR = 2.47, 95% CI 2.02 to 3.02) compared to RF-negative (RR = 1.58, 95% CI 1.15 to 2.18) when comparing the highest versus lowest category of pack-years for the individual studies.

Conclusions

Lifelong cigarette smoking was positively associated with the risk of RA even among smokers with a low lifelong exposure. The risk of RA did not further increase with an exposure higher than 20 pack-years.

Periodontal disease in Thai patients with rheumatoid arthritis

AIM

To evaluate the prevalence and severity of periodontal disease in patients with rheumatoid arthritis (RA) who attended a rheumatology clinic in a university hospital.

METHODS

All consecutive patients with RA who attended the rheumatology clinic between June 2009 and January 2010 were asked to enroll in this study. All participants answered questionnaires, which included demographic data, medical history, medications used and smoking habits. A full mouth periodontal examination, including gingival index, plaque index, probing pocket depth and clinical attachment level was performed. Only cases that had at least 20 teeth were included in this study. Rheumatoid arthritis parameters, including number of tender and swollen joints, erythrocyte sedimentation rate, the presence of rheumatoid factor (RF), hand radiographs, Disease Activity Index (DAS) and health status using the Thai Health Assessment Questionnaire (HAQ), were determined. The association between RA parameters and periodontal condition was examined.

RESULTS

There were 196 participants (87.2% female) with a mean age of 51.7 ± 9.70 years, mean disease duration of 9.62 ± 7.0 years and mean DAS score of 4.64 ± 1.25. Eighty-two per cent were RF-positive. Moderate and severe periodontitis were found in 42% and 57%, respectively. Higher age, male gender, previous or current smoking and high level of plaque score were associated with severe periodontal disease. No differences in RA parameters were found between groups of patients who had moderate and severe periodontitis.

CONCLUSIONS

We found a high prevalence of periodontitis in Thai patients with RA. However, there was no association between RA parameters and periodontal conditions.

Vitamin E supplementation, superoxide dismutase status, and outcome of scaling and root planing in patients with chronic periodontitis: a randomized clinical trial

BACKGROUND

This study investigates the levels of superoxide dismutase (SOD) activity in serum and saliva of patients with chronic periodontitis (CP). In addition, the outcome of scaling and root planing (SRP) with and without vitamin E supplementation is evaluated in terms of changes in periodontal parameters and SOD activity in patients with CP.

METHODS

Serum and salivary SOD activity in 38 patients with CP were compared with those of 22 systemically and periodontally healthy individuals (control group). At periodontal examination, serum and saliva samples were obtained. Patients with CP were randomly divided into treatment groups 1 (TG-1) and 2 (TG-2). SRP was performed for both groups, and TG-2 also received 200 mg (300 IU) vitamin E every other day. Periodontal parameters and SOD activity were evaluated after 3 months. SOD activity was determined using an SOD assay and enzyme-linked immunosorbent assay reader at 450 nm.

RESULTS

SOD activity in both serum (P <0.05) and saliva (P <0.001) was lower in patients with CP compared with controls. After 3 months of follow-up, SOD activity improved in both treatment groups; however, the improvement in TG-2 was higher than in TG-1, along with more improvement in periodontal parameters. Serum SOD levels in TG-2 increased even above the level of the control group.

CONCLUSIONS

Systemic and local SOD levels are lowered in CP. Adjunctive vitamin E supplementation improves periodontal healing as well as antioxidant defense.