Mechanisms of Systemic Osteoporosis in Rheumatoid Arthritis

Curcumin-loaded scaffolds in bone regeneration

In recent years, there has been a notable surge in the development of engineered bone scaffolds intended for the repair of bone defects. While autografts and allografts have traditionally served as the primary methods in bone tissue engineering, their inherent limitations have spurred the exploration of novel avenues in biomedical implant development. The emergence of bone scaffolds not only facilitates bone reconstruction but also offers a platform for the targeted delivery of therapeutic agents. There exists a pervasive interest in leveraging various drugs, proteins, growth factors, and biomolecules with osteogenic properties to augment bone formation, as the enduring side effects associated with current clinical modalities necessitate the pursuit of safer alternatives. Curcumin, the principal bioactive compound found in turmeric, has demonstrated notable efficacy in regulating the proliferation and differentiation of bone cells while promoting bone formation. Nevertheless, its utility is hindered by restricted water solubility and poor bioavailability. Strategies aimed at enhancing the solubility, stability, and bioavailability of curcumin, including formulation techniques such as liposomes and nanoparticles or its complexation with metals, have been explored. This investigation is dedicated to exploring the impact of curcumin on the proliferation, differentiation, and migration of osteocytes, osteoblasts, and osteoclasts.

Application of two-sample Mendelian randomization method to assess the causal relationship between rheumatoid arthritis and osteoporotic fracture

Background

The association between rheumatoid arthritis (RA) and osteoporotic fracture has garnered considerable attention; however, the causal relationships between diseases remain uncertain. Therefore, this study employed Mendelian randomization (MR) analysis to investigate the causal effects of RA on osteoporotic fracture.

Methods

The summary data for RA and osteoporotic fracture were extracted from the genome-wide association studies (GWAS) catalog and the Finn Biobank database. The database provides information about diseased and health control subjects. We searched the database for the following conditions: RA, osteoporosis (OP), and osteoporotic fractures. Entries were published by investigating centers, which had established definitions and diagnostic criteria. We downloaded and processed the data to obtain the single-nucleotide polymorphisms (SNPs) strongly associated with RA, OP, and osteoporotic fracture. RA genetic associations were obtained from the GWAS catalog, including 1961 cases and 454,387 controls. The osteoporosis of the GWAS catalog involved 991 cases and 455,357 controls, and the data of the Finn Biobank involved 8,017 cases and 391,037 controls. Genetic associations for osteoporotic fracture were taken from the Finn Biobank of 1822 cases and 311,210 controls. Independent SNPs that are significantly associated with meeting the criteria of p < 5 × 10-8, r2 < 0.001, and kb = 10,000 were selected for MR analysis. The inverse variance-weighted (IVW) method along with other MR methods was employed for analysis, while sensitivity analyses were conducted to assess reliability and stability.

Results

The results provided strong evidence that RA was causally and positively associated with osteoporosis from the GWAS catalog (OR = 1.16590; 95% CI: 1.04067-1.30619; p = 0.00811) and the Finn Biobank database (OR = 1.07314; 95% CI: 1.03455-1.11317; p = 0.00016). Moreover, a positive causal relationship was detected between RA and osteoporotic fracture (OR = 1.10132; 95% CI: 1.00506-1.20680; p = 0.03863). The results were robust according to sensitivity tests.

Conclusion

This study showed positive causal relationships between RA and osteoporotic fracture. These results should be considered in further studies and public health measures on osteoporosis prevention strategies.

Patient preference, efficacy, and compliance with zoledronic acid for glucocorticoid-induced osteoporosis in patients with autoimmune diseases

PURPOSE

We evaluated the preference, patient satisfaction, and efficacy of zoledronic acid compared with oral bisphosphonates (BPs) for glucocorticoid-induced osteoporosis (GIOP) in patients with autoimmune diseases.

METHODS

We enrolled 50 patients with new fractures or osteoporosis detected on follow-up bone densitometry after at least 1 year of oral BP use among patients diagnosed with GIOP during treatment for autoimmune diseases. After 1 year of zoledronic acid treatment, patients completed a survey for preference and satisfaction assessment. Treatment efficacy was analysed by comparing bone mineral density changes and fractures with those in a control group of patients who continued oral BP use.

RESULTS

Age, sex, treatment duration, and medication history did not differ significantly between the two groups. Among the participants, 86.7% preferred and were more satisfied with intravenous zoledronic acid than with oral BPs, primarily because of the convenience of its administration interval. Only two patients (4%) reported infusion-related adverse events with zoledronic acid. Furthermore, no significant differences were observed in the annualized percentage change in the bone mineral density of the lumbar spine, femur neck, and hip between patients receiving zoledronic acid and those receiving oral BPs. The occurrence of new fractures was consistent across both groups, with two cases in each, showing no significant differences.

CONCLUSION

Patients showed a preference for and greater satisfaction with zoledronic acid, and its efficacy in treating osteoporosis was comparable to that of oral BPs. Therefore, zoledronic acid is a suitable treatment option for GIOP in patients with autoimmune diseases.

Rheumatoid arthritis, disease-modifying antirheumatic drugs and risk of major osteoporotic fracture: prospective data from the HUNT Study, Norway

OBJECTIVES

Rheumatoid arthritis has been associated with increased fracture risk. New treatments have improved the course of the disease substantially, but it is not clear if this influences fracture risk. We examined if rheumatoid arthritis, overall and according to disease-modifying antirheumatic drugs (DMARDs), is associated with a risk of major osteoporotic fractures.

METHODS

Overall, 92 285 participants in the population-based Nord-Trndelag Health Study (HUNT), Norway were included and linked with hospital records for a validated rheumatoid arthritis diagnosis (n=605), type of DMARD treatment and fracture diagnosis. Participants were followed up until the first major osteoporotic fracture, death, emigration or end of follow-up. Cox regression was used to estimate HRs for fractures among individuals with rheumatoid arthritis, overall and by DMARD treatment, compared with participants without rheumatoid arthritis.

RESULTS

A total of 9670 fractures were observed during follow-up, of which 88 were among those with rheumatoid arthritis. Compared with the reference group of participants without rheumatoid arthritis, those with the disease had an HR of fracture of 1.41 (95% CI 1.13 to 1.74). The association was largely similar for users of csDMARDs (HR 1.44; 95% CI 1.15 to 1.81), whereas the association for bDMARD users was weaker and less precise (HR 1.19; 95% CI 0.64 to 2.21).

CONCLUSION

Participants with rheumatoid arthritis had a 40% higher risk of fracture than participants without the disease. A similar fracture risk was observed for conventional synthetic DMARD use, whereas there was weak evidence that the use of biological DMARDs may be associated with a somewhat lower fracture risk.

LncRNA-mediated cell autophagy: An emerging field in bone destruction in rheumatoid arthritis

In recent years, research on the mechanism of bone destruction in rheumatoid arthritis (RA) has remained in the initial stages, and the mechanism has not been fully elucidated to date. Recent studies have shown that long noncoding RNAs (lncRNAs) participate in RA bone destruction via autophagy, but the specific regulatory mechanism of lncRNA-mediated autophagy is unclear. Therefore, in this article, we review the mechanisms of lncRNA-mediated autophagy in fibroblast-like synoviocytes and chondrocytes in RA bone destruction. We explain that lncRNAs mediate autophagy and participate in many specific pathological processes of RA bone destruction by regulating signalling pathways and the expression of target genes. Specific lncRNAs can be used as markers for molecular diagnosis, mechanistic regulation, treatment and prognosis of RA.

Cartilage and bone loss in premenopausal women with rheumatoid arthritis: Radiological and laboratory assessments

INTRODUCTION

To investigate the radiological and laboratory features of bone and cartilage losses in premenopausal women with rheumatoid arthritis (RA).

METHODS

This case-control study is the continuation of a study that was conducted on 48 women with RA and 48 matched healthy volunteers. All RA patients were previously subjected to clinical examination, disease activity assessment using the 28-joint Disease Activity Score (DAS28) and Clinical Disease Activity Index (CDAI), serological tests, dual-energy X-ray absorptiometry measuring bone mineral density (BMD), and plain X-ray of both hands. Added to these, matrix metalloproteinase 3 (MMP-3) and cartilage oligomeric matrix protein (COMP) were measured by enzyme-linked immunosorbent assay.

RESULTS

There were statistically significant differences between patients and controls regarding COMP and MMP-3, being higher in patients (p < .001). COMP and MMP-3 have significant positive correlation with serum levels of anti-cyclic citrullinated peptide (anti-CCP) and anti-carbamylated protein (anti-CarP). The original Sharp erosion score was positively correlated with the serum level of the studied antibodies and disease duration, but no significant correlation was found with either COMP, MMP-3, or DAS-28. Spine BMD and Z score were negatively correlated with disease activity and anti-CarP. There were significant positive relationhsips between indices of local cartilage and bone loss and the indices of systemic bone loss. MMP-3 had no correlation with indices of local cartilage and bone loss and disease activity scores.

CONCLUSIONS

The pathogenic mechanism of hand joint damage involved the three studied autoantibodies namely, rheumatoid factor, anti-CCP and anti-CarP antibodies. Anti-CarP antibody was involved in the reduction of BMD of the spine. The association between systemic osteoporosis and hand joint damage pointed to a common pathogenic mechanism.

Long-Term Use of Immunosuppressive Agents Increased the Risk of Fractures in Patients with Autoimmune Diseases: An 18-Year Population-Based Cohort Study

The risk of fractures is higher in patients with autoimmune diseases, but it is not clear whether the use of immunosuppressive agents can further increase this risk. To investigate this issue, a retrospective study was conducted using data from Taiwan's National Health Insurance Research Database. Patients diagnosed with autoimmune diseases between 2000 and 2014, including psoriatic arthritis, rheumatoid arthritis, ankylosing spondylitis, and systemic lupus erythematosus, were included in the study. A control group of patients without autoimmune diseases was selected from the same database during the same period. Patients with autoimmune diseases were divided into two sub-cohorts based on their use of immunosuppressive agents. This study found the risk of fractures was 1.14 times higher in patients with autoimmune diseases than in those without. Moreover, we found that patients in the immunosuppressant sub-cohort had a higher risk of fractures compared to those in the non-immunosuppressant sub-cohort. The adjusted sub-distribution hazard ratio for shoulder fractures was 1.27 (95% CI = 1.01-1.58), for spine fractures was 1.43 (95% CI = 1.26-1.62), for wrist fractures was 0.95 (95% CI = 0.75-1.22), and for hip fractures was 1.67 (95% CI = 1.38-2.03). In conclusion, the long-term use of immunosuppressive agents in patients with autoimmune diseases may increase the risk of fractures.

The causal relationship between autoimmune diseases and osteoporosis: a study based on Mendelian randomization

Objective

The relationship between different autoimmune diseases and bone mineral density (BMD) and fractures has been reported in epidemiological studies. This study aimed to explore the causal relationship between autoimmune diseases and BMD, falls, and fractures using Mendelian randomization (MR).

Methods

The instrumental variables were selected from the aggregated statistical data of these diseases from the largest genome-wide association study in Europe. Specifically, 12 common autoimmune diseases were selected as exposure. Outcome variables included BMD, falls, and fractures. Multiple analysis methods were utilized to comprehensively evaluate the causal relationship between autoimmune diseases and BMD, falls, and fractures. Additionally, sensitivity analyses, including Cochran's Q test, MR-Egger intercept test, and one analysis, were conducted to verify the result's reliability.

Results

Strong evidence was provided in the results of the negatively association of ulcerative colitis (UC) with forearm BMD. UC also had a negatively association with the total body BMD, while inflammatory bowel disease (IBD) depicted a negatively association with the total body BMD at the age of 45-60 years. Horizontal pleiotropy or heterogeneity was not detected through sensitivity analysis, indicating that the causal estimation was reliable.

Conclusion

This study shows a negative causal relationship between UC and forearm and total body BMD, and between IBD and total body BMD at the age of 45-60 years. These results should be considered in future research and when public health measures and osteoporosis prevention strategies are formulated.

The Pathogenesis of Rheumatoid Arthritis Breakthroughs in Molecular Mechanisms 1 and 2

The pathogenesis of rheumatoid arthritis (RA) consists of the formation of synovial villi, inflammation, immune abnormalities, and bone-cartilage destruction [...].

The comparable efficacy of denosumab on bone mineral density in rheumatoid arthritis patients with postmenopausal osteoporosis: A retrospective case-control study

Little is known about differences in the therapeutic efficacy of denosumab in subjects with and without rheumatoid arthritis (RA). This study compares the changes in bone mineral density (BMD) between RA patients and controls without RA who had been treated with denosumab for 2 years for postmenopausal osteoporosis. A total of 82 RA patients and 64 controls were enrolled, who were refractory to selective estrogen receptor modulators (SERMs) or bisphosphonates and completed the treatment of denosumab 60 mg for 2 years. The efficacy of denosumab in RA patients and controls was assessed using areal BMD (aBMD) and T-score of the lumbar spine, femur neck, and total hip. A general linear model with repeated measures analysis of variance was used to determine differences in aBMD and T-score between 2 study groups. No significant differences in percent changes in aBMD and T-scores by denosumab treatment for 2 years at the lumbar spine, femur neck, and total hip were evident between RA patients and controls (P > .05 of all), except T-score of the total hip (P = .034). Denosumab treatment equally increased aBMD at the lumbar spine and T-scores at the lumbar spine and total hip between RA patients and controls without statistical differences, but RA patients showed less improvement in aBMD at the femur neck (ptime*group = 0.032) and T-scores at the femur neck and total hip than controls (ptime*group = 0.004 of both). Changes in aBMD and T-scores after denosumab treatment in RA patients were not affected by previous use of bisphosphonates or SERMs. Differences of T-score at the femur neck among previous bisphosphonate users and aBMD and T-score at the femur neck and T-scores at the total hip were evident. This study revealed that 2 years of denosumab treatment in female RA patients achieved comparable efficacy on BMD to controls at the lumbar spine, but showed somewhat insufficient improvement at the femur neck and total hip.

Chronic arthritides and bone structure: focus on rheumatoid arthritis-an update

Normal bone remodeling depends of a balance between bone forming cells, osteoblasts and bone resorbing cells, the osteoclasts. In chronic arthritides and some inflammatory and autoimmune diseases such as rheumatoid arthritis, there is a great constellation of cytokines produced by pannus that impair bone formation and stimulate bone resorption by inducing osteoclast differentiation and inhibiting osteoblast maturation. Patients with chronic inflammation have multiple causes that lead to low bone mineral density, osteoporosis and a high risk of fracture including circulating cytokines, impaired mobility, chronic administration of glucocorticoids, low vitamin D levels and post-menopausal status in women, among others. Biologic agents and other therapeutic measures to reach prompt remission might ameliorate these deleterious effects. In many cases, bone acting agents need to be added to conventional treatment to reduce the risk of fractures and to preserve articular integrity and independency for daily living activities. A limited number of studies related to fractures in chronic arthritides were published, and future investigation is needed to determine the risk of fractures and the protective effects of different treatments to reduce this risk.

Pathogenesis of Extraarticular Manifestations in Rheumatoid Arthritis-A Comprehensive Review

Rheumatoid arthritis (RA) is among the most prevalent and debilitating autoimmune inflammatory chronic diseases. Although it is primarily characterized by destructive peripheral arthritis, it is a systemic disease, and RA-related extraarticular manifestations (EAMs) can affect almost every organ, exhibit a multitude of clinical presentations, and can even be asymptomatic. Importantly, EAMs largely contribute to the quality of life and mortality of RA patients, particularly substantially increased risk of cardiovascular disease (CVD) which is the leading cause of death in RA patients. In spite of known risk factors related to EAM development, a more in-depth understanding of its pathophysiology is lacking. Improved knowledge of EAMs and their comparison to the pathogenesis of arthritis in RA could lead to a better understanding of RA inflammation overall and its initial phases. Taking into account that RA is a disorder that has many faces and that each person experiences it and responds to treatments differently, gaining a better understanding of the connections between the joint and extra-joint manifestations could help to create new treatments and improve the overall approach to the patient.

Identification of novel meQTLs strongly associated with rheumatoid arthritis by large-scale epigenome-wide analysis

Rheumatoid arthritis (RA) is highly heritable, and previous studies have suggested that genetic variation may affect susceptibility to RA by altering epigenetic modifications (e.g. DNA methylation). Here we examined how genetic variation influences DNA methylation (DNAm) in RA by integrating individual genetic variation and DNAm data. Epigenome-wide meQTL (methylation quantitative trait loci) analysis was performed on 354 RA patients and 335 controls, scanning 30,101,744 relationships between 62 SNPs and 485,512 DNA methylation sites. Two regulatory relationship pairs (FDR < 0.05) showed very strong associations with RA risk. One was rs10796216-cg00475509, and the DNAm decreased by 0.0168 per addition of allele rs10796216-A. The other was rs6546473-cg13358873, for which a 0.0365 reduction of DNAm at cg13358873 was observed for each addition of allele rs6546473-A, and lower DNAm was found to be significantly associated with RA risk (P = 2.0407e-28). Moreover, both pairs of meQTL showed a strong regulatory relationship only in RA samples, so they can be subsequently considered as risk markers for RA. In conclusion, our integrated analysis of genetic and epigenetic variation suggests that genetic variation may affect the risk of RA by regulating DNA methylation levels. Alterations of DNAm at cg00475509 and cg13358873 loci conferred by rs10796216-A and rs6546473-A allele may suggest a potential risk for RA. Our results deepen our understanding of the genetic and epigenetic mechanisms of RA and provide novel associations that can be further investigated in future studies.