Bone Mineral Density in Sjögren Syndrome Patients with and Without Distal Renal Tubular Acidosis

Hydroxychloroquine and risk of osteoporosis in patients with rheumatoid arthritis: A population-based retrospective study of 6408 patients

AIM

Patients with rheumatoid arthritis (RA) are at a higher risk of osteoporotic fractures. Studies have shown that patients with Sjogren's syndrome (SS) and systemic lupus erythematosus (SLE) experienced an increase in bone mineral density (BMD) after receiving hydroxychloroquine (HCQ) treatment, indicating a potential protective effect against osteoporosis. Therefore, this study is to examine the relationship between HCQ usage and the risk of osteoporosis in patients diagnosed with RA.

METHODS

The retrospective cohort study used data from Taiwan's National Health Insurance Research Database (NHIRD) covering the period from January 2010 to December 2018, which included 14 050 newly diagnosed RA patients, subsequently divided into two groups: HCQ users and non-users. Propensity score matching (PSM) based on sex, age, urbanization, insured unit type, insured area, and comorbidities was conducted to match the groups. The primary outcome assessed was the evaluation of the risk of osteoporosis by employing a multivariable Cox proportional hazard regression model to calculate the adjusted hazard ratio (aHR).

RESULTS

After PSM, a total of 6408 RA patients were included in the analysis (3204 HCQ users and 3204 non-users). There was no significantly higher risk of osteoporosis in HCQ users compared with non-users, aHR = 0.99 (95% CI: 0.82-1.196). Additionally, different durations of HCQ usage demonstrated a neutral effect on the risk of osteoporosis [HCQ <90 days, aHR = 0.88 (95% CI: 0.585-1.324); HCQ 90-180 days, aHR = 0.941 (95% CI: 0.625-1.418); HCQ >180 days, aHR = 1.019 (95% CI: 0.832-1.249)].

CONCLUSIONS

The study indicates that there is no significant association between the use of HCQ and the risk of osteoporosis in patients with RA.

In vitro effect of hydroxychloroquine on pluripotent stem cells and their cardiomyocytes derivatives

Introduction: Hydroxychloroquine (HDQ) is an antimalarial drug that has also shown its effectiveness in autoimmune diseases. Despite having side effects such as retinopathy, neuromyopathy and controversial cardiac toxicity, HDQ has been presented and now intensively studied for the treatment and prevention of coronavirus disease 2019 (COVID-19). Recent works revealed both beneficial and toxic effects during HDQ treatment. The cardiotoxic profile of HDQ remains unclear and identifying risk factors is challenging. Methods: Here, we used well-established cell-cultured to study the cytotoxic effect of HDQ, mouse induced pluripotent stem cells (miPSC) and their cardiomyocytes (CMs) derivatives were exposed to different concentrations of HDQ. Cell colony morphology was assessed by microscopy whereas cell viability was measured by flow cytometry and impedance-based methods. The effect of HDQ on beating activity of mouse and human induced pluripotent stem cell-derived CMs (miPSC-CMs and hiPSC-CMs, respectively) and mouse embryonic stem cell-derived CMs (mESC-CMs) were captured by the xCELLigence RTCA and microelectrode array (MEA) systems. Results and discussion: Our results revealed that 20 µM of HDQ promotes proliferation of stem cells used suggesting that if appropriately monitored, HDQ may have a cardioprotective effect and may also represent a possible candidate for tissue repair. In addition, the field potential signals revealed that higher doses of this medication caused bradycardia that could be reversed with a higher concentration of ß-adrenergic agonist, Isoproterenol (Iso). On the contrary, HDQ caused an increase in the beating rate of hiPSC-CMs, which was further helped upon application of Isoproterenol (Iso) suggesting that HDQ and Iso may also work synergistically. These results indicate that HDQ is potentially toxic at high concentrations and can modulate the beating activity of cardiomyocytes. Moreover, HDQ could have a synergistic inotropic effect with isoproterenol on cardiac cells.

Renal tubular acidosis and associated factors in patients with primary Sjögren's syndrome: a registry-based study

OBJECTIVES

To investigate the clinical features and factors associated with primary Sjögren's syndrome (pSS)-associated renal tubular acidosis (RTA).

METHOD

This case-control study was based on a multicenter pSS registry established by the Chinese Rheumatism Data Center. Patients with pSS, including those with RTA and those without renal involvement, between May 2016 and March 2020 were included in the analysis. Demographic, clinical, and laboratory data were also collected. Univariate and multivariate logistic regression analyses were used to identify factors that were associated with pSS-RTA.

RESULTS

This study included 257 pSS patients with RTA and 4222 patients without renal involvement. Significantly younger age at disease onset (40.1 ± 14.1 vs. 46.2 ± 13.1 years, P < 0.001), longer diagnosis interval (15.0 interquartile range [IQR] [1.0, 48.0] vs. 6.0 IQR [0, 34.0] months, P < 0.001), higher EULAR Sjögren's syndrome disease activity index (9 IQR [5, 15] vs. 3 IQR [0, 8], P < 0.001), and a higher prevalence of decreased estimated glomerular filtration rate (25.0% vs. 6.6%, P < 0.001) were observed in pSS patients with RTA than in those without renal involvement. Factors that were independently associated with pSS-RTA included age at disease onset ≤ 35 years (odds ratio [OR] 3.00, 95% confidence interval [CI] 2.27-3.97), thyroid disorders (OR 1.49, 95% CI 1.04-2.14), subjective dry mouth (OR 3.29, 95% CI 1.71-6.35), arthritis (OR 1.57, 95% CI 1.10-2.25), anti-SSB antibody positivity (OR 1.80, 95% CI 1.33-2.45), anemia (OR 1.67, 95% CI 1.26-2.21), elevated alkaline phosphatase level (OR 2.14, 95% CI 1.26-3.65), decreased albumin level (OR 1.61, 95% CI 1.00-2.60), and elevated erythrocyte sedimentation rate (OR 1.78, 95% CI 1.16-2.73).

CONCLUSIONS

Delayed diagnosis and decreased kidney function are common in pSS patients with RTA. pSS should be considered in patients with RTA, and early recognition and treatment may be useful in slowing the deterioration of renal function in patients with pSS-RTA. Key Points • pSS patients with RTA have earlier disease onset and higher disease activity than pSS patients without RTA, but the diagnosis was frequently delayed. • Decreased kidney function are common in pSS patients with RTA. • Sjögren's syndrome should be considered in young female patients with unexplained RTA, whereas RTA should be screened in pSS patients with early disease onset and elevated ALP level.

The Effect of Anti-rheumatic Drugs on the Skeleton

The therapeutic armamentarium for rheumatoid arthritis has increased substantially over the last 20 years. Historically antirheumatic treatment was started late in the disease course and frequently included prolonged high-dose glucocorticoid treatment which was associated with accelerated generalised bone loss and increased vertebral and non-vertebral fracture risk. Newer biologic and targeted synthetic treatments and a combination of conventional synthetic DMARDs prevent accelerated systemic bone loss and may even allow repair of cortical bone erosions. Emerging data also gives new insight on the impact of long-term conventional synthetic DMARDs on bone health and fracture risk and highlights the need for ongoing studies for better understanding of "established therapeutics". An interesting new antirheumatic treatment effect is the potential of erosion repair with the use of biologic DMARDs and janus kinase inhibitors. Although several newer anti-rheumatic drugs seem to have favorable effects on bone mineral density in RA patients, these effects are modest and do not seem to influence the fracture risk thus far. We summarize recent developments and findings of the impact of anti-rheumatic treatments on localized and systemic bone integrity and health.

Musculoskeletal Manifestations in Sjogren's Syndrome: An Orthopedic Point of View

Sjogren's syndrome (SS) is a frequent entity with a broad symptomatology spectrum, mainly affecting the salivary and lachrymal glands. The disease also affects the musculoskeletal system targeting bones, specific joints, muscles, and the peripheral nerve system. Disease related clinical manifestations canhave an accumulative impact, as the syndrome is commonly associated with other rheumatic diseases. A literature review was performed with the aim to assess the in-depth association of Sjogren's syndrome and its treatment agents with the musculoskeletal system and further investigate its potential relevance with common orthopedic postoperative complications.

Association between comorbidities and extraglandular manifestations in primary Sjögren's syndrome: a multicenter cross-sectional study

INTRODUCTION

Primary Sjögren's syndrome (pSS) has been related to a higher risk of comorbidities, but studies examining comorbidities among patients with and without extraglandular manifestations are limited. The objectives of this study were to assess the prevalence of comorbidities in Chinese pSS patients and to determine the relationship between comorbidities and extraglandular manifestations.

METHOD

This cross-sectional study was based on the multicenter pSS registry established by the Chinese Rheumatism Data Center. Patients fulfilling the 2002 American-European criteria or the 2016 classification criteria for pSS were enrolled from May 2016 to December 2018. Demographic data, disease characteristics, comorbidities (cardiovascular disease, thyroid disorder, malignancy, and fragility fracture), and extraglandular manifestations were collected. Multivariate analyses were used to assess the relationships between comorbidities and extraglandular manifestations.

RESULTS

A total of 4087 pSS patients were included (95.7% female and mean age of 51.2 ± 13.1 years). The baseline prevalence of comorbidities was 3.8% for cardiovascular diseases, 12.1% for thyroid disorders, 1.8% for malignancies, and 1.7% for fragility fractures. The presence of extraglandular manifestations was associated with more comorbidities. Patients with more than one extraglandular manifestation had a higher prevalence of cardiovascular disease (adjusted odds ratio [aOR] 2.004, 95% confidence interval [CI] 1.221-3.288), thyroid disorder (aOR 1.380, 95% CI 1.022-1.863), and fragility fracture (aOR 2.684, 95% CI 1.505-4.786) after adjustment for age, sex, disease duration, and the significant variables in the univariate analysis.

CONCLUSIONS

The presence of extraglandular manifestations in pSS was associated with an increased comorbidity burden, especially cardiovascular disease, thyroid disorder, and fragility fracture. Key Points • This is the first study assessing the association between extraglandular manifestations and comorbidity burden based on the largest pSS registry in China. • Patients with multiple extraglandular manifestations tend to have increased comorbid cardiovascular disease, thyroid disorder, and fragility fracture.

Ten-year fracture risk by FRAX and osteoporotic fractures in patients with systemic autoimmune diseases

The Fracture Risk Assessment Tool (FRAX) has been used universally for the purpose of fracture risk assessment. However, the predictive capacity of FRAX for autoimmune diseases remains inconclusive. This study aimed to compare the applicability of FRAX for autoimmune disease patients. This retrospective study recruited rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary Sjögren syndrome (pSS) patients with bone mineral density (BMD) tests. Patients with any osteoporotic fractures were identified. Taiwan-specific FRAX with and without BMD were then calculated. In total, 802 patients (451 RA, 233 SLE and 118 pSS) were enrolled in this study. The cumulative incidences of osteoporotic fractures in the RA, SLE and pSS patients were 43.0%, 29.2% and 33.1%, respectively. For those with a previous osteoporotic fracture, T-scores were classified as low bone mass. Overall, the patients' 10-year probability of major fracture risk by FRAX without BMD was 15.8%, which then increased to 20.3% after incorporation of BMD measurement. When analyzed by disease group, the fracture risk in RA patients was accurately predicted by FRAX. In contrast, current FRAX, either with or without BMD measurement, underestimated the fracture risk both in SLE and pSS patients, even after stratification by age and glucocorticoid treatment. For pSS patients with major osteoporotic fractures, FRAX risks imputed by RA were comparable to major osteoporotic fracture risks of RA patients. Current FRAX accurately predicted fracture probability in RA patients, but not in SLE and pSS patients. RA-imputed FRAX risk scores could be used as a temporary substitute for SLE and pSS patients.

Hydroxychloroquine decreases human MSC-derived osteoblast differentiation and mineralization in vitro

We recently showed that patients with primary Sjögren Syndrome (pSS) have significantly higher bone mineral density (BMD) compared to healthy controls. The majority of those patients (69%) was using hydroxychloroquine (HCQ), which may have favourable effects on BMD. To study the direct effects of HCQ on human MSC‐derived osteoblast activity. Osteoblasts were cultured from human mesenchymal stromal cells (hMSCs). Cultures were treated with different HCQ doses (control, 1 and 5 µg/ml). Alkaline phosphatase activity and calcium measurements were performed to evaluate osteoblast differentiation and activity, respectively. Detailed microarray analysis was performed in 5 µg/ml HCQ‐treated cells and controls followed by qPCR validation. Additional cultures were performed using the cholesterol synthesis inhibitor simvastatin (SIM) to evaluate a potential mechanism of action. We showed that HCQ inhibits both MSC‐derived osteoblast differentiation and mineralization in vitro. Microarray analysis and additional PCR validation revealed a highly significant up‐regulation of the cholesterol biosynthesis, lysosomal and extracellular matrix pathways in the 5 µg/ml HCQ‐treated cells compared to controls. Besides, we demonstrated that 1 µM SIM also decreases MSC‐derived osteoblast differentiation and mineralization compared to controls. It appears that the positive effect of HCQ on BMD cannot be explained by a stimulating effect on the MSC‐derived osteoblast. The discrepancy between high BMD and decreased MSC‐derived osteoblast function due to HCQ treatment might be caused by systemic factors that stimulate bone formation and/or local factors that reduce bone resorption, which is lacking in cell cultures.