Bone health in systemic lupus erythematosus

Bone mineral density in egyptian children with juvenile idiopathic arthritis: possible correlation to serum RANKL / osteoprotegerin (OPG) ratio and OPG gene polymorphisms

BACKGROUND

Children with juvenile idiopathic arthritis (JIA) are at higher risk of decreased bone mineral density (BMD) compared with healthy children due to genetic, disease and medication-related causes. This study aims to investigate the possible effects of osteoprotegerin (OPG) gene polymorphisms and serum levels of osteoprotegerin (OPG) and receptor activator of nuclear factor κB-ligand (RANKL) and RANKL/OPG ratio on BMD in children with JIA.

METHODS

OPG gene rs2073617, rs3134069, serum RANKL, OPG and RANKL/OPG ratio were evaluated in 60 JIA children and 100 matched healthy controls. BMD was evaluated by lumbar dual energy X-ray absorptiometry (DEXA) according to which patients were classified in 2 groups (DEXA z-score above and below - 2). Composite disease activity was measured using the Juvenile Arthritis Disease Activity Score (JADAS) 27-joints. Articular damage was scored using the juvenile arthritis damage index (JADI).

RESULTS

Patients aged 12.05 ± 3.2 years, included 38 females and 31% had BMD z-score below-2. Systemic-onset JIA was the most frequent phenotype (38%). Genotypes and alleles frequencies of the 2 studied polymorphisms did not differ between patients and controls (p > 0.05 for all) while serum RANKL and RANKL/OPG ratio were significantly higher in patients compared to controls (p = < 0.001 and 0.03 respectively). Patients with BMD < -2 had significantly greater frequencies of rs2073617 TT genotype and T allele (p < 0.001), higher serum RANKL, RANKL/OPG ratio (p = 0.01, 0.002), female predominance (p = 0.02), higher articular and extra-articular damage index (p = 0.008,0.009) and more frequent steroid usage (p = 0.02) compared to patients with BMD z-score >-2. Multivariate analysis showed rs2073617 TT genotype, RANKL/OPG ratio, long disease duration (above 36 months) and use of steroid to be associated with decreased BMD (p = 0.03,0.04,0.01,0.01 respectively) in JIA children.

CONCLUSIONS

Egyptian children with JIA have decreased BMD. rs2073617 TT genotype and T allele, RANKL/OPG ratio are possible determinants of reduced BMD in JIA. Our results underline the importance of frequent monitoring of BMD in JIA children and trying to control disease activity to preserve long term bone health.

Low prevalence of bone mineral density testing in patients with systemic lupus erythematosus and glucocorticoid exposure

SummaryPatients with systemic lupus erythematosus (SLE) have an increased risk of developing osteoporosis and fractures due to systemic inflammation and glucocorticoids (GCs). Professional organizations recommend bone mineral density (BMD) testing in SLE patients on GCs, especially within 6 months of initiation. Using a validated algorithm, we identified SLE patients in an electronic health record cohort with long-term GC exposure (≥90 days). Our primary outcome was ever BMD testing. We assessed the impact of patient and provider factors on testing. We identified 693 SLE cases with long-term GC exposure, 41% of whom had BMD testing performed. Only 18% of patients had BMD testing within 6 months of GC initiation. In a logistic regression model for BMD testing, male sex (OR = 0.49, 95% CI 0.27 - 0.87, p = 0.01) was associated with being less likely to have BMD testing after adjusting for race and ethnicity. In contrast, older age (OR = 1.04, p < 0.001) and nephritis (OR = 1.83, p = 0.003) were associated with being more likely to have BMD testing after adjusting for race and ethnicity. Bone health in SLE patients remains an area in need of improvement with attention to patients who are younger and male.

Serum RANKL, osteoprotegerin (OPG) and RANKL/OPG ratio in children with systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE) patients have lower bone mineral density (BMD) compared with healthy individuals because of general, genetic, disease and medication-related factors. The disturbance of the receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) ratio has been reported to be associated with low BMD in many disorders in adults and children alike.

Objectives

The objectives of this study were (i) to assess serum OPG, RANKL and RANKL/OPG ratio levels in SLE children and controls, (ii) to determine whether the cumulative glucocorticoid (CGCS) dose had any effect on the concentration of serum RANKL, OPG and RANKL/OPG ratio, and (iii) to determine the relation of these parameters to BMD.

Methods

We evaluated 50 SLE children and 50 age- and sex-matched healthy controls. RANKL and OPG were assessed in serum and compared between patients and controls. For SLE patients, a univariate followed by multivariable analysis were carried out to detect the possible predictors of the changes in RANKL, OPG and RANKL/OPG ratio levels. Lumbar BMD for all patients was assessed by dual-energy X-ray absorptiometry (DXA) scan and then correlated to different probable correlated factors.

Results

RANKL, OPG and RANKL/OPG ratio were significantly higher in SLE patients ( p ≤ 0.001). Univariate analysis showed significant correlations of RANKL with CGCS ( p ≤ 0.001) and with DXA scan z-score ( p = 0.007): OPG was significantly correlated to Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score ( p = 0.001) and anti-double-stranded DNA ( p = 0.001), whereas RANKL/OPG was significantly correlated to duration of illness and DXA z-score ( p = 0.002). The multivariable analysis showed that DXA z-score was an independent predictor of RANKL and RANKL/OPG ratio ( p = 0.019 and 0.008, respectively), whereas SLEDAI score was an independent predictor of OPG levels. BMD was negatively correlated to disease duration ( p = 0.008) and CGCS dose ( p = 0.015), but no significant correlation has been found between BMD and cumulative SLEDAI score ( p = 0.29).

Conclusions

Serum RANKL/OPG ratio is elevated in Egyptian children with SLE and is considered a risk factor for reduced bone mass in these children. Other risk factors for low BMD include high CGCS dose and disease duration, supporting that osteoporosis in SLE is multifactorial.

Associations Between Bone Mass in Women With Fibromyalgia and Widespread Pressure Pain Hypersensitivity, Tenderness, Perceived Pain Level, and Disability

This study aimed to evaluate the impact of fibromyalgia syndrome (FMS) on bone mass assessed by calcaneal quantitative ultrasound (QUS) in pre- and postmenopausal women and determine whether there are associations between bone status and pressure pain thresholds (PPTs), tender point counts (TPCs), self-reported global pain, or disease severity. Ninety-five women with a diagnosis of FMS and 108 healthy controls matched on menopause status were included in this cross-sectional study. PPT and TPC were measured by algometry pressure. Self-reported global pain and disease severity were evaluated by Visual Analogue Scale and Fibromyalgia Impact Questionnaire, respectively. Bone mass was assessed with calcaneus QUS. Broadband ultrasound attenuation (BUA; dB/MHz) and speed of sound (SOS; m/s) were significantly lower in the FMS patients compared with controls ( p = .027 and p = .003, respectively). Linear regression analysis revealed that all PPTs were significantly associated with the BUA parameter after adjustments for body mass index (BMI), menopause status, and physical activity in women with FMS ( p < .05). TPC was also significantly associated with BUA after adjustments for covariables (β = .241, 95% confidence interval [0.333, 3.754], p = .020). No significant differences were found between any QUS measurements and global pain or disease severity. Calcaneal BUA and SOS values were lower in women with FMS compared to healthy controls, and decreased pain thresholds and higher TPCs were associated with lower calcaneal BUA values. Low pain thresholds might be independent predictors for low bone mass in FMS women.

Inflammatory bone loss associated with MFG-E8 deficiency is rescued by teriparatide

A prolonged increase in proinflammatory cytokines is associated with osteoporotic and autoimmune bone loss and, conversely, anti-inflammatory pathways are associated with protection against bone loss. Milk fat globule-epidermal growth factor (MFG-E)-8 is a glycoprotein that is proresolving, regulates apoptotic cell clearance, and has been linked to autoimmune disease and skeletal homeostasis. The role of MFG-E8 in the young vs. adult skeleton was determined in mice deficient in MFG-E8 (KO). In vivo, trabecular bone was similar in MFG-E8KO and wild-type (WT) mice at 6 and 16 wk, whereas 22 wk adult MFG-E8KO mice displayed significantly reduced trabecular BV/TV. The number of osteoclasts per bone surface was increased in 22-wk MFG-E8 KO vs. WT mice, and recombinant murine MFG-E8 decreased the number and size of osteoclasts in vitro. Adult MFG-E8KO spleen weight:body weight was increased compared with WT, and flow cytometric analysis showed significantly increased myeloid-derived suppressor cells (CD11b^hiGR-1⁺) and neutrophils (CD11b^hiLy6G⁺) in MFG-E8KO bone marrow, suggesting an inflammatory phenotype. PTH-treated MFG-E8KO mice showed a greater anabolic response (+124% BV/TV) than observed in PTH-treated WT mice (+64% BV/TV). These data give insight into the role of MFG-E8 in the adult skeleton and suggest that anabolic PTH may be a valuable therapeutic approach for autoimmune-associated skeletal disease.-Michalski, M. N., Seydel, A. L., Siismets, E. M., Zweifler, L. E., Koh, A. J., Sinder, B. P., Aguirre, J. I., Atabai, K., Roca, H., McCauley, L. K. Inflammatory bone loss associated with MFG-E8 deficiency is rescued by teriparatide.

Fracture risk and bone mineral density levels in patients with systemic lupus erythematosus: a systematic review and meta-analysis

Previous studies suggested possible bone loss and fracture risk in patients with systemic lupus erythematosus (SLE). The aim of this systematic review and meta-analysis was to assess the strength of the relationship of SLE with fracture risk and the mean difference of bone mineral density (BMD) levels between SLE patients and controls. Literature search was undertaken in multiple indexing databases on September 26, 2015. Studies on the relationship of SLE with fracture risk and the mean difference of BMD levels between SLE patients and controls were included. Data were combined using standard methods of meta-analysis. Twenty-one studies were finally included into the meta-analysis, including 15 studies on the mean difference of BMD levels between SLE patients and controls, and 6 studies were on fracture risk associated with SLE. The meta-analysis showed that SLE patients had significantly lower BMD levels than controls in the whole body (weighted mean difference [WMD] = -0.04; 95 % CI -0.06 to -0.02; P < 0.001), femoral neck (WMD = -0.06; 95 % CI -0.07 to -0.04; P < 0.001), lumbar spine (WMD = -0.06; 95 % CI -0.09 to -0.03; P < 0.001), and total hip (WMD = -0.05; 95 % CI -0.06 to -0.03; P < 0.001). In addition, the meta-analysis also showed that SLE was significantly associated with increased fracture risk of all sites (relative risk [RR] = 1.97, 95 % CI 1.20-3.25; P = 0.008). Subgroup analysis by adjustment showed that SLE was significantly associated with increased fracture risk of all sites before and after adjusting for confounding factors (unadjusted RR = 2.07, 95 % CI 1.46-2.94, P < 0.001; adjusted RR = 1.22, 95 % CI 1.05-1.42, P = 0.01). Subgroup analysis by types of fracture showed that SLE was significantly associated with increased risks of hip fracture (RR = 1.99, 95 % CI 1.55-2.57; P < 0.001), osteoporotic fracture (RR = 1.36, 95 % CI 1.21-1.53; P < 0.001), and vertebral fracture (RR = 2.97, 95 % CI 1.71-5.16; P < 0.001). This systematic review and meta-analysis provides strong evidence for the relationship of SLE with bone loss and fracture risk.

Loss of milk fat globule-epidermal growth factor 8 (MFG-E8) in mice leads to low bone mass and accelerates ovariectomy-associated bone loss by increasing osteoclastogenesis

Milk fat globule-epidermal growth factor 8 (MFG-E8) is a glycoprotein that controls the engulfment of apoptotic cells and exerts inflammation-modulatory effects. Recently, it has been implicated in osteoclastogenesis and the pathogenesis of inflammatory periodontal bone loss, but its role in physiological bone homeostasis is still not well defined. Here, we evaluated the influence of MFG-E8 on osteoblasts and osteoclasts and its impact on bone remodeling in healthy and ovariectomized mice as a model for post-menopausal osteoporosis. Total and trabecular bone mineral densities at the lumbar spine in 6-week-old MFG-E8 KO mice were reduced by 11% (p < 0.05) and 17% (p < 0.01), respectively, as compared to wild-type (WT) mice. Accordingly, serum levels of the bone formation marker P1NP were decreased by 37% (p < 0.01) in MFG-E8 KO mice as were the ex vivo mineralization capacity and expression of osteoblast genes (Runx2, alkaline phosphatase, osteocalcin) in MFG-E8 KO osteoblasts. In contrast, serum bone resorption markers CTX1 and TRAP5b were increased by 30% and 60% (p < 0.05), respectively, in MFG-E8 KO mice. Furthermore, bone marrow macrophages from MFG-E8-KO mice differentiated more effectively into osteoclasts, as compared to WT cells. MFG-E8-deficient osteoclasts displayed increased bone resorption ex vivo, which could be reversed by the presence of recombinant MFG-E8. To determine the significance of the enhanced osteoclastogenesis in MFG-E8 KO mice, we performed an ovariectomy, which is associated with bone loss due to increased osteoclast activity. Indeed, MFG-E8 KO mice lost 12% more trabecular bone density than WT mice after ovariectomy. Together, these data indicate that MFG-E8 controls steady-state and pathological bone turnover and may therefore represent a new target gene in the treatment of bone diseases.

Significantly higher estimated 10-year probability of fracture in lupus patients with bone mineral density comparable to that of healthy individuals

This study aimed at comparing the FRAX 10-year fracture risk between SLE patients and demographically- and anthropometrically matched healthy individuals. Consecutive SLE patients aged ≥ 40 were analyzed for the FRAX 10-year probability of major osteoporotic and hip fractures and their risk was compared with healthy controls matched for age, gender and body mass index. Potential determinants associated with higher 10-year fracture probability in the SLE patients were studied by regression models. Ninety subjects (45 SLE patients and 45 healthy controls) were studied. While the bone mineral density (BMD) of the lumbar spine and dominant hip was comparable between the two groups, the FRAX 10-year probability of major and hip fractures was significantly higher in SLE patients. Significantly more SLE patients had high 10-year fracture risk as defined by the National Osteoporosis Foundation compared with healthy controls (16 vs. 2 %, p = 0.026). After controlling for glucocorticoid use and premature menopause which were significant univariate risk factors, the difference in the 10-year fracture risk became insignificant. Amongst SLE patients, increasing age, lower hip BMD and cumulative glucocorticoid dose independently predicted higher 10-year major fracture risk while higher anti-dsDNA level independently predicted higher hip fracture risk in addition to age and lower hip BMD. Chronic glucocorticoid use and premature menopause led to higher 10-year probability of major osteoporotic and hip fractures in SLE patients compared with their healthy counterparts although their BMD was comparable. Advanced age, lower hip BMD, cumulative glucocorticoid and higher anti-dsDNA level independently predicted higher 10-year fracture risk amongst SLE patients.

Soluble receptor activator of nuclear factor κB ligand/osteoprotegerin ratio is increased in systemic lupus erythematosus patients

INTRODUCTION

Systemic lupus erythematosus (SLE) patients have lower bone mineral density and increased fracture risk when compared with healthy individuals, due to distinct factors and mechanisms. Bone remodeling is a tightly orchestrated process dependent on several factors, including the balance between receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG). Our aim was to assess serum OPG and soluble RANKL (sRANKL) levels as well as sRANKL/OPG ratio in female SLE patients and compare it with female controls.

METHODS

We have evaluated 103 SLE patients and 114 healthy controls, all Caucasian females. All participants underwent a clinical and laboratory evaluation. sRANKL and OPG were quantified in serum by ELISA based methods. sRANKL, OPG and sRANKL/OPG ratio levels were compared between SLE patients and age, sex and race matched healthy controls. For SLE patients, a multivariate analysis was performed, to find the possible predictors of the changes in sRANKL, OPG and sRANKL/OPG ratio levels.

RESULTS

Although sRANKL levels did not differ between the two groups, serum OPG was lower in SLE patients (P < 0.001). This led to an increased sRANKL/OPG ratio (P = 0.010) in the patients' group.The multivariate analysis was performed considering age and other clinical and laboratorial potential confounders for these variations in the SLE patients group. We have showed that age (P = 0.001) and levels of anti-Sm antibodies (P = 0.016) were independent predictors of sRANKL/OPG ratio variations in SLE patients. No relationship with therapy or disease activity measured by SLEDAI2K was found.

CONCLUSIONS

These results are suggestive of increased osteoclastic stimuli driven by the SLE disease mechanisms.

Achados de imagem das alterações musculoesqueléticas associadas ao lúpus eritematoso sistêmico

O lúpus eritematoso sistêmico é uma doença autoimune que envolve múltiplos sistemas orgânicos. O acometimento musculoesquelético é uma das manifestações mais comuns da doença, com envolvimento ósseo, articular, muscular, tendíneo e ligamentar, tanto primário como relacionado ao tratamento instituído. Neste artigo revisamos e ilustramos as alterações articulares e complicações musculoesqueléticas mais comuns relacionadas a esta doença.

Skeletal manifestations of systemic autoimmune diseases

PURPOSE OF REVIEW

There is an increased risk of osteoporotic fractures and osteonecrosis often at a young age among patients with certain systemic autoimmune diseases. The loss of bone mineral density and bone integrity seen with these diseases often cannot be explained by traditional risk factors alone. In this review, we focus on rheumatoid arthritis and systemic lupus erythematosus, two systemic autoimmune diseases in which skeletal manifestations have been well described.

RECENT FINDINGS

There is recent evidence that autoimmunity and its associated inflammation and vitamin D deficiency play key roles in the pathogenesis of adverse skeletal effects.

SUMMARY

Understanding these processes carries implications for the prevention and treatment of osteoporosis and osteonecrosis among patients with autoimmune diseases.

Drug monitoring in systemic lupus erythematosus: a systematic review

OBJECTIVES

To conduct an evidence-based review of the common medication toxicities and strategies and utility of drug toxicity monitoring among patients with systemic lupus erythematosus (SLE).

METHODS

PubMed and other databases were searched for articles published between the years 1960 and 2010 for keywords referring to medication toxicity or monitoring strategies for 7 drugs commonly used in SLE. All relevant English-language articles were reviewed. Most of the evidence we reviewed comprised studies that addressed the incidence of toxicity-randomized trials that compare different monitoring strategies for these drugs do not exist.

RESULTS

Data to describe the frequency of adverse events and appropriate strategies for screening for these events are scarce. Toxicities do not appear to be substantially more common among patients with SLE compared to other conditions for which these drugs are used.

CONCLUSIONS

Our review demonstrates that the scientific basis for many aspects of drug toxicity monitoring is weak and that most current recommendations are based largely on expert consensus. We present a future research agenda to address these gaps.

Increased expression of human T-cell immunoglobulin- and mucin-domain-containing molecule-4 in peripheral blood mononuclear cells from patients with system lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease. Innate and adaptive immunity cooperatively contribute to the development of SLE. Antigen-presenting cells (APCs) have been suggested to link innate and adaptive immunity. T-cell immunoglobulin- and mucin-domain-containing molecule-4 (Tim-4; also known as Timd4), expressed primarily on the surface of APCs, is a member of the TIM family, a recently described group of molecules that have received much attention as potential regulators of the immune system. In this study, we used quantitative real-time reverse transcription-polymerase chain reaction to examine the mRNA expression of Tim-4 in peripheral blood mononuclear cells (PBMCs) from SLE patients and further analyzed the correlation between the expression of Tim-4 and Tim-1 (a potential ligand for Tim-4) in PBMCs and serum tumor necrosis factor (TNF)-alpha levels. The results showed that Tim-4 mRNA expression in PBMCs was significantly higher in SLE patients than in healthy controls, especially those patients in the active phase of disease. Moreover, Tim-4 mRNA levels were closely correlated with Tim-1 mRNA levels in PBMCs and with serum TNF-alpha levels in SLE patients but not in the control group. Taken together, these results demonstrate that Tim-4 may be involved in the pathogenesis of SLE.