Higher serum uric acid levels are associated with reduced risk of hip osteoporosis in postmenopausal women with rheumatoid arthritis

Elevated uric acid is associated with a low bone mineral density in pre- but not post-menopausal women with rheumatoid arthritis: a pilot study

INTRODUCTION

The role of uric acid (UA) on bone metabolism is controversially discussed. Higher UA levels have been associated with higher T-scores and a reduced incidence of fractures in postmenopausal women. However, in the context of rheumatoid arthritis (RA), the role of UA remains unclear. This pilot study aimed to investigate the association of UA levels with bone mineral density in RA female and male patients.

METHODS

This pilot study analyzed patients with RA to explore preliminary associations. We utilized data from the Rh-GIOP cohort, a prospective monocentric observational study focusing on bone health in chronic rheumatic diseases. To assess the association between UA levels and the lowest T-scores measured at the lumbar spine, hip, or femur, we used linear regression with adjustment for various confounders. An interaction term was included to evaluate differential associations in pre- and postmenopausal women.

RESULTS

Data on dual X-ray absorptiometry (DXA) measurements and serum UA levels were analyzed in a total of 206 patients. Among the 167 women 16 were premenopausal (age 40 ± 8 years) and 149 postmenopausal (age 65 ± 10 years). As expected, postmenopausal had lower T-scores than premenopausal patients (-1.53 ± 1.01 versus - 0.41 ± 1.29, respectively). No association of UA levels with T-scores was found when analyzing the whole cohort (Slope β: -0.04; p = 0.45). However, a significant negative correlation of UA with T-scores in premenopausal (Slope β: -0.98; p = 0.014), but not postmenopausal (Slope β: -0.04; p > 0.05) women was found.

CONCLUSION

Uric acid appears to be negatively associated with bone mineral density in premenopausal but not in postmenopausal women with RA. Thus, the impact of UA on bone health seems to depend on the hormonal status of women. Further investigations are required to validate these results in a larger cohort of patients and to investigate the underlying mechanisms.

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).

Risk Genetic Variants (IL-10) for Osteoporosis in Han Population from Northwest China

Background

Osteoporosis (OP) is a common metabolic bone disease characterized by loss of bone mass. IL-10 is considered to be a powerful immune and inflammatory suppressor. This study aimed to assess association between genetic loci in IL-10 and susceptibility to OP.

Methods

Association analysis between IL-10 genetic loci and OP risk through SNPStats online software. FPRP analysis (false-positive report probability) verified whether the positive results were noteworthy findings. Linkage disequilibrium (LD) and haplotype analysis were completed by Haploview 4.2 and SNPStats. Multi-factor dimensionality reduction (MDR) was used to assess interaction of SNP-SNP in susceptibility to OP.

Results

Allele "G" of IL-10-rs1554286 (OR = 1.21, p = 0.013), allele "C" of IL-10-rs1518111 (OR = 1.22, p = 0.011), allele "C" of IL-10-rs3024490 (OR = 1.20, p = 0.018), and allele "G" of IL-10-rs1800871 (OR = 1.21, p = 0.015) were risk factors for OP. In females, smoking, drinking, or aging ≤60 years old participants, the above genetic loci are also significantly associated with the increased risk of OP. FPRP analysis showed that all positive results are noteworthy findings. There are significant differences in serum levels of uric acid, mean hemoglobin concentration, or mean hemoglobin among different genotypes of IL-10 gene loci. MDR showed that four loci model composed rs1554286, rs1518111, rs3021094, and rs1800871 is the best model for predicting OP risk.

Conclusion

IL-10-rs1554286, -rs1518111, -rs3021094, and -rs1800871 are risk factors for susceptibility to OP.

Gout as a risk factor for osteoporosis: A Korean population-based study

Uric acid acts as both an antioxidant and a pre-oxidant that induces oxidative stress; thus, it plays a paradoxical role in inflammation. However, the effect of gout, a hallmark of hyperuricemia, on osteoporosis remains unclear. Therefore, this study aimed to investigate the association between gout and osteoporosis. This retrospective cohort study used data from the Korean National Health Insurance Service Database. In total, 628,565 participants who were diagnosed with gout and prescribed medications for gout for at least 90 days were selected. The control cohort included patients with no history of gout or use of gout medication. Age and sex 1:1 propensity score matching and Cox proportional hazards models were used to investigate risk factors for osteoporosis. In total, 305,810 patients with gout met the inclusion criteria. Compared with the control group, both men and women with gout showed an increased incidence rate ratio of osteoporosis. In the stratified analysis by age, patients with gout showed an increased incidence rate ratio for osteoporosis in all age groups, except for those over 80 years of age (P < .001). Gout showed an increased hazard ratio of 1.48 (95% CI: 1.45-1.51, P < .001). The female sex has also been identified as a risk factor for osteoporosis. Patients in their 70s had the highest HR. Gout is significantly associated with the risk of osteoporosis. In particular, the results of this study showed that the incidence of osteoporosis increased up to four times in male patients in their 20s with gout compared to without gout.

Associations of Neutrophil-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio and Monocyte-to-Lymphocyte Ratio with Osteoporosis and Incident Vertebral Fracture in Postmenopausal Women with Rheumatoid Arthritis: A Single-Center Retrospective Cohort Study

Background and Objectives: We investigated whether nutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphoycte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) are associated with the presence of osteoporosis (OP) and vertebral fractures in patients with rheumatoid arthritis (RA). Materials and Methods: This retrospective cohort study included 413 postmenopausal patients with RA and 200 healthy controls who underwent dual-energy X-ray absorptiometry (DEXA) between January 2005 and December 2017. DEXA examination data were defined as the index date, and all laboratory values were measured within one month from the index date. OP was defined as a T-score < −2.5, and incident vertebral fractures were defined as the first occurrence of non-traumatic fractures after the index date. NLR, PLR, and MLR measures were dichotomized by a median split (low vs. high). Results: The median NLR, PLR, and MLR in RA patients were significantly higher than those in controls. The frequencies of OP of the lumbar spine, hip, and either site in postmenopausal patients with RA were 24.7%, 15.5%, and 32%, respectively, and were significantly higher than those in controls. After adjusting for confounding factors, a high baseline NLR was significantly associated with OP at either site (OR = 1.61, p = 0.041). In addition, high baseline NLR (OR = 2.11, p = 0.025) and PLR (OR = 2.3, p = 0.011) were related with the presence OP at hip. During the follow-up period, 53 (12.8%) patients with RA developed vertebral fractures incidentally. In multivariable Cox regression models, a high baseline NLR (HR = 4.72, p < 0.001), PLR (HR = 1.96, p = 0.024), and MLR (HR = 2.64, p = 0.002) were independently associated with a higher risk of incidental vertebral fractures. Conclusions: Our data suggest that NLR, PLR, and MLR can be used as potential markers of systemic bone loss among individuals with RA.

Osteoporosis in patients with rheumatoid arthritis is associated with serum immune regulatory cellular factors

OBJECTIVE

Osteoporosis (OP) is a comorbidity of rheumatoid arthritis (RA) that largely causes disability. This study discussed the expression patterns of serum immunoregulatory factors and their clinical significance in RA patients complicated with OP.

METHODS

A total of 116 RA patients were enrolled. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry to allocate patients to OP group (N = 62) and non-OP group (N = 54). CRP, rheumatoid factor, IgG, IgA, and IgM were detected using rate nephelometry. Erythrocyte sedimentation rate (ESR) and bone metabolic indexes were detected using Microsed automatic ESR analyzer and Cobas e601 automated immunoassay systems and reagents. IL-17, IL-6, TNF-α, IL-10, and IL-4 levels were determined using ELISA kit and their prediction values on OP were analyzed using the ROC curve. Influencing factors of OP incidence were analyzed using logistic regression model.

RESULTS

RA patients with OP showed increased age, disease course, tender and swollen joints, ESR, CRP, DAS28 scores, β-CTX, IL-17, IL-6, and TNF-α, and decreased 25(OH)D3, IL-10, and IL-4. DAS28 was positively correlated with IL-17, IL-6, and TNF-α, and negatively correlated with IL-10 and IL-4. DAS28, IL-17, IL-10, and IL-4 were independently correlated with OP in RA patients. The combination of DAS28, IL-17, IL-10, and IL-4 can better predict the incidence of OP complication in RA patients.

CONCLUSION

IL-17, IL-6, TNF-α, IL-10, and IL-4 were associated with disease activity of RA patients complicated with OP. A combination of DAS28, IL-17, IL-10, and IL-4 might predict OP incidence in RA patients.

Differential Proteomic Identification and Bioinformatics Analysis of Femoral Neck in Elderly Female Patients with Hyperuricaemia

Background::

Serum uric acid (UA) is positively correlated with bone mineral density (BMD). However, the mechanism by which serum UA affects BMD remains unclear.

Objective::

The aim was carried out to search for the functional proteins related to serum UA and femoral neck BMD to better understand the pathophysiological mechanism of osteoporosis.

Materials and methods::

In this study, patients in the UA group (hyperuricaemia combined with femoral neck fracture) and the control group (normal uricaemia combined with femoral neck fracture) were selected according to the inclusion criteria. Total protein was extracted from the femoral neck of each patient. Fluorescence differential gel electrophoresis was used to separate the total proteins, and the differentially expressed protein spots were detected by image analysis. After enzyme digestion, peptide mass fingerprinting and database searches were performed to identify the differentially expressed proteins. DAVID software and Kyoto Encyclopedia of Genes and Genomes (KEGG) data were used for enrichment analysis of the screened differential proteins.

Results::

After mass spectrometry and database searching, 66 differentially expressed protein spots were identified between the UA group and the control group. Most differentially expressed proteins functioned in cytoskeleton formation, energy metabolism, or signal transduction. They were mainly involved in 50 biological processes, including peroxisome proliferator-activated receptor (PPAR) signalling and fatty acid metabolism. PPARγ and PLIN1 were subject to Western blotting analysis detection; results were consistent with the Label-Free result.

Conclusion::

Based on an analysis of the biological information, these proteins may be associated with the incidence and progression of the femoral neck bone tissues of hyperuricaemia patients.

Why Does Hyperuricemia Not Necessarily Induce Gout?

Hyperuricemia is a risk factor for gout. It has been well observed that a large proportion of individuals with hyperuricemia have never had a gout flare(s), while some patients with gout can have a normuricemia. This raises a puzzle of the real role of serum uric acid (SUA) in the occurrence of gout flares. As the molecule of uric acid has its dual effects in vivo with antioxidant properties as well as being an inflammatory promoter, it has been placed in a delicate position in balancing metabolisms. Gout seems to be a multifactorial metabolic disease and its pathogenesis should not rely solely on hyperuricemia or monosodium urate (MSU) crystals. This critical review aims to unfold the mechanisms of the SUA role participating in gout development. It also discusses some key elements which are prerequisites for the formation of gout in association with the current therapeutic regime. The compilation should be helpful in precisely fighting for a cure of gout clinically and pharmaceutically.