Uncoupled bone remodeling is characteristic of bone damage in premenopausal women with new-onset systemic lupus erythematosus

Interplay Between Skeletal and Hematopoietic Cells in the Bone Marrow Microenvironment in Homeostasis and Aging

PURPOSE OF THE REVIEW

In this review, we discuss the most recent scientific advances on the reciprocal regulatory interactions between the skeletal and hematopoietic stem cell niche, focusing on immunomodulation and its interplay with the cell's mitochondrial function, and how this impacts osteoimmune health during aging and disease.

RECENT FINDINGS

Osteoimmunology investigates interactions between cells that make up the skeletal stem cell niche and immune system. Much work has investigated the complexity of the bone marrow microenvironment with respect to the skeletal and hematopoietic stem cells that regulate skeletal formation and immune health respectively. It has now become clear that these cellular components cooperate to maintain homeostasis and that dysfunction in their interaction can lead to aging and disease. Having a deeper, mechanistic appreciation for osteoimmune regulation will lead to better research perspective and therapeutics with the potential to improve the aging process, skeletal and hematologic regeneration, and disease targeting.

Factors associated with osteoporosis and fractures in patients with systemic lupus erythematosus: Kyoto Lupus Cohort

OBJECTIVES

Osteoporosis and compression fractures of the lumbar spine are some of the major adverse effects of glucocorticoid therapy in patients with systemic lupus erythematosus (SLE). This study examined the association between bone mineral density, bone turnover markers, presence of vertebral fractures, and Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index in SLE patients.

METHODS

This was a cross-sectional study of 246 outpatients with SLE at the Kyoto University Hospital. Lumbar and femoral bone mineral density was measured with dual-energy X-ray absorptiometry, and the presence of vertebral fractures was determined using X-ray, computed tomography, or magnetic resonance imaging.

RESULTS

On multiple regression analysis, both high lumbar and femoral T-scores were associated with the concomitant use of hydroxychloroquine (P = .018 and P = .037, respectively), no use of bisphosphonate or denosumab (P = .004 and P = .038, respectively), high body mass index (P < .001), and low bone-specific alkaline phosphatase level (P = .014 and P = .002, respectively). Vertebral fractures showed a significant association with Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index score (P < .001) and femoral T-score (P < .001).

CONCLUSION

Vertebral fracture was associated with SLE-associated organ damage, and serum bone-specific alkaline phosphatase level is a potentially useful marker for osteoporosis monitoring in SLE patients.

Glucocorticoid-induced osteoporosis in premenopausal women: management for the rheumatologist

PURPOSE OF REVIEW

This review seeks to summarize the literature relevant to the treatment of glucocorticoid-induced osteoporosis in premenopausal women; an issue commonly encountered by rheumatologists and yet lacking good clinical practice guidelines.

RECENT FINDINGS

Although most of the relevant literature on osteoporosis includes postmenopausal women only, data from both randomized controlled trials and case reports suggest bisphosphonates can be an effective and well tolerated treatment for premenopausal patients. Data for other medications to treat premenopausal osteoporosis is less robust.

SUMMARY

The use of bisphosphonates in young women may be safer than initially thought and should likely be used for the treatment of glucocorticoid-induced osteoporosis in rheumatology clinics. Further research is needed to continue to understand long-term risk.

Therapeutic Treatments for Osteoporosis-Which Combination of Pills Is the Best among the Bad?

Osteoporosis is a chronical, systemic skeletal disorder characterized by an increase in bone resorption, which leads to reduced bone density. The reduction in bone mineral density and therefore low bone mass results in an increased risk of fractures. Osteoporosis is caused by an imbalance in the normally strictly regulated bone homeostasis. This imbalance is caused by overactive bone-resorbing osteoclasts, while bone-synthesizing osteoblasts do not compensate for this. In this review, the mechanism is presented, underlined by in vitro and animal models to investigate this imbalance as well as the current status of clinical trials. Furthermore, new therapeutic strategies for osteoporosis are presented, such as anabolic treatments and catabolic treatments and treatments using biomaterials and biomolecules. Another focus is on new combination therapies with multiple drugs which are currently considered more beneficial for the treatment of osteoporosis than monotherapies. Taken together, this review starts with an overview and ends with the newest approaches for osteoporosis therapies and a future perspective not presented so far.

A tissue-selective estrogen complex as treatment of osteoporosis in experimental lupus

Osteoporosis is a common secondary complication in patients with systemic lupus erythematosus (SLE). Current osteoporosis treatment with bisphosphonates has some negative side effects and there is a lack of data regarding newer treatments options for SLE associated osteoporosis. The tissue-selective estrogen complex (TSEC) containing conjugated estrogens and the selective estrogen receptor modulator bazedoxifene (Bza) is approved for treatment of postmenopausal vasomotor symptoms and prevention of osteoporosis. However, it has not been evaluated for treatment of osteoporosis in postmenopausal SLE patients. Ovariectomized MRL/lpr mice constitute a model for postmenopausal lupus that can be used for osteoporosis studies. We used this model in a set of experiments where the mice were treated with different doses of 17β-estradiol-3-benzoate (E2), Bza, or TSEC (E2 plus Bza), administered in the early or late phases of disease development. The skeleton was analyzed by dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and high-resolution microcomputed tomography. The lupus disease was assessed by determination of proteinuria, hematuria, and lupus disease markers in serum. Treatment with medium dose TSEC administered in early disease protected ovariectomized MRL/lpr mice from trabecular bone loss, while there were no differences in lupus disease parameters between treatments. This is the first experimental study to investigate TSEC as a potential new therapy for osteoporosis in postmenopausal SLE.

Impact of menopause on women with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by chronic and systemic inflammation affecting multiple organ systems, including an increased risk of cardiovascular disease due to the SLE-associated hyperinflammatory state. SLE shows a strong female predominance, suggesting a potential role of sex hormones in the pathogenesis of the disease. Evidence suggests an earlier age of menopause among women with SLE, despite mixed findings regarding other markers of ovarian aging. In healthy populations, the menopausal transition is associated with important physiologic changes resulting in increased cardiometabolic risk and risk of osteoporosis. Thus, women with SLE who experience the inflammatory effects of the autoimmune condition combined with the (potentially earlier) menopausal transition may represent a particularly vulnerable group of individuals during a particular window of time. Little is known, however, about strategies for cardiovascular risk or bone loss mitigation in women with SLE during the menopausal transition. Further, despite lack of knowledge regarding the burden of menopausal symptoms in women with SLE, existing recommendations provide only cautionary guidance for the use of hormone replacement therapy to address menopausal symptoms in this population. Importantly, the data regarding both SLE and menopause-associated cardiovascular and osteoporotic risk demonstrate the critical need for additional research to identify the type and timing of treatments or interventions needed to best mitigate this increased risk.

Role of Exosomal MicroRNAs and Their Crosstalk with Oxidative Stress in the Pathogenesis of Osteoporosis

Osteoporosis (OP) is an aging-related disease involving permanent bone tissue atrophy. Most patients with OP show high levels of oxidative stress (OS), which destroys the microstructure of bone tissue and promotes disease progression. Exosomes (exos) help in the delivery of microRNAs (miRNAs) and allow intercellular communication. In OP, exosomal miRNAs modulate several physiological processes, including the OS response. In the present review, we aim to describe how exosomal miRNAs and OS contribute to OP. We first summarize the relationship of OS with OP and then detail the features of exos along with the functions of exo-related miRNAs. Further, we explore the interplay between exosomal miRNAs and OS in OP and summarize the functional role of exos in OP. Finally, we identify the advantages of exo-based miRNA delivery in treatment strategies for OP. Our review seeks to improve the current understanding of the mechanism underlying OP pathogenesis and lay the foundation for the development of novel theranostic approaches for OP.