Glucocorticoid-induced osteoporosis: an update

Disease activity score is associated with vertebral fragility fractures in patients with rheumatoid arthritis: a cross-sectional multidisciplinary study

Rheumatoid Arthritis (RA) is associated with osteometabolic alterations. This study aims to estimate the prevalence of osteometabolic complications and to explore the potential association with disease parameters in patients with RA. This cross-sectional study enrolled consecutive patients with diagnosis of RA, admitted to Rheumatology Unit of our Hospital and referred to the Endocrinology Unit for the assessment of osteometabolic health. Anamnestic, anthropometric, biochemical and instrumental data were collected for each subject. The prevalence of osteometabolic alterations was 35% for sarcopenia, 41% for osteoporosis and 28% for vertebral fragility fractures in a population of 110 RA patients. At multivariable analysis, copeptin showed direct association (β-coeff 0.006; p = 0.015) with lower lumbar bone mineral density (BMD) values on dual-energy X-ray absorptiometry (DXA). Disease Activity Score for 28 joints with C-Reactive Protein (DAS28-CRP) (OR 1.632; p = 0.031) proved to be associated with vertebral fragility fractures, correcting for age, sex, body mass index (BMI) and disease parameters. Furthermore, DAS28-CRP (β-coeff 0.584; p = 0.001), steroid therapy (β-coeff 0.993; p = 0.013), and old age (β-coeff 0.040; p = 0.013) were directly associated with sarcopenia score (SARC-F), while male sex showed indirect association (β-coeff - 1.027; p = 0.036), correcting for autoantibody positivity and BMI. In the last model, copeptin resulted indirectly associated with fat mass index on DXA (β-coeff - 0.236, p = 0.049), using age and disease parameters, as covariates. RA is characterized by a high prevalence of osteometabolic complications, caused by a complex interplay between autoimmune and metabolic pathways. Management of osteometabolic health in RA patients should be a shared decision making between rheumatologist and endocrinologist.

Comparison of different intervention thresholds for the treatment of glucocorticoid-induced osteoporosis: a cross-sectional study

BACKGROUND

Glucocorticoid-induced osteoporosis (GIO) is the most common drug-induced osteoporosis. Early detection and treatment may decrease the fragility fractures. Several GIO guidelines exist, although they vary in recommended intervention thresholds for initiating pharmacologic treatment. This study aimed to evaluate the performance of intervention thresholds in treating GIO under various guidelines.

METHODS

Rheumatic disease patients receiving ≥ 2.5 mg/day prednisolone or equivalent for longer than 3 months between January 2013 and 2023 were retrospectively reviewed. Patients who were previously treated with anti-osteoporotic medications or had other secondary causes of osteoporosis were excluded. Bone mineral density (BMD) and Thailand-specific FRAX with glucocorticoid adjustment (GC-FRAX) were recorded. The performances of different intervention thresholds from six GIO guidelines (ACR 2022, Belgian 2022, TOPF 2021, Korean 2018, Malaysian 2015, and Japanese 2023) were examined against the incidence of actual fragility fractures.

RESULTS

This study included 226 rheumatic patients, with a mean (SD) age of 62.9 (10.1) years. Most of the patients were female (88.9%). The average (SD) daily dose, cumulative dose, and duration of glucocorticoid use were 4.6 (10.6) mg/day, 9,223.4 (9,223.4) mg, and 58.3 (55.8) months, respectively. Diagnoses included rheumatoid arthritis (59.8%), systemic lupus erythematosus (22%), inflammatory myositis (4.7%), systemic sclerosis (4.7%), and others. The prevalence of major osteoporotic fractures and hip fractures was 14.2% and 0.9%, respectively. The ten-year probabilities of major osteoporotic and hip fractures (FRAX) with and without BMD were 12.6 ± 9.1, 5.4 ± 6, 10.7 ± 7.2, and 4.6 ± 4.8, respectively. The mean (SD) ten-year FRAX probabilities of major osteoporotic and hip fractures were 12.6% (9.1) and 5.4% (6) with the inclusion of BMD result, and 10.7% (7.2) and 4.6% (4.8) without the inclusion of the BMD result. The sensitivity, specificity and accuracy of the ACR 2022, Belgian 2022, TOPF 2021, Korean 2018, Malaysian 2015, and Japanese 2023 guidelines were 100%/ 3.1%/ 16.8%, 93.8%/ 14.4%/ 25.7%, 93.8%/ 43.8%/ 50.9%, 100%/ 17.5%/ 29.2%, 78.1%/ 62.9%/ 65% and 100%/ 24.2%/ 35%, respectively.

CONCLUSIONS

Among evaluated guidelines, ACR 2022, Korean 2018, and Japan 2023 had the highest sensitivity for GIO treatment, while Malaysian 2015 showed the highest specificity and accuracy. These findings can improve clinical decision-making in GIO management for rheumatic disease patients.

The Role of Ferroptosis in Osteoporosis and Advances in Chinese Herbal Interventions

OP, a systemic bone disorder marked by reduced bone mass and heightened fracture risk, poses a significant global health burden, particularly among aging populations. Current treatments, including bisphosphonates and calcium supplementation, are limited by adverse effects and incomplete efficacy. Emerging research highlights ferroptosis-an iron-dependent cell death driven by lipid peroxidation-as a critical contributor to OP pathogenesis, characterized by dysregulated iron metabolism, oxidative stress, and lipid peroxide accumulation, which disrupt bone remodeling by impairing osteoblast function and enhancing osteoclast activity. This review elucidates the mechanistic interplay between ferroptosis and OP subtypes (diabetic osteoporosis (DOP), glucocorticoid-induced (GIOP), and postmenopausal osteoporosis (PMOP)) and evaluates the efficacy of Chinese herbal interventions in mitigating ferroptosis-driven bone loss. Key findings reveal that excess iron exacerbates lipid peroxidation via the Fenton reaction, while glutathione peroxidase 4 (GPX4) inactivation and system Xc- inhibition amplify oxidative damage. In DIOP, hyperglycemia-induced ROS and advanced glycation end products suppress osteogenesis, countered by melatonin and naringenin via nuclear factor -related factor 2 (Nrf2)/GPX4 activation. GIOP involves dexamethasone-mediated GPX4 downregulation, mitigated by exosomes and melatonin through phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling. PMOP driven by estrogen deficiency-induced iron overload is alleviated by aconitine and icariin (ICA) via nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription 3 (STAT3) pathways. Chinese herbs, including active compounds (quercetin, gastrodin, ICA, etc.) and formulations (Bugu Shengsui Capsule, Erxian Decoction (EXD), etc.), regulate iron metabolism, enhance antioxidant defenses (Nrf2/heme oxygenase 1(HO-1)), and inhibit lipid peroxidation, effectively restoring bone homeostasis. These findings underscore ferroptosis as a pivotal mechanism in OP progression and highlight the therapeutic promise of Chinese herbs in bridging traditional medicine with modern mechanistic insights. Future research should prioritize elucidating precise molecular targets, optimizing formulations, and validating clinical efficacy to address current therapeutic gaps.

Methotrexate continuation increases fracture risk in patients who sustained lower limb insufficiency fractures

OBJECTIVES

Two recent case series and previous case reports have described methotrexate (MTX)-associated insufficiency fractures, so called methotrexate osteopathy (MTXO). Our aim was to assess whether the continuation of MTX after an insufficiency fracture impacts future fracture risk.

METHODS

Retrospective single-centre case note review of patients who suffered MTXO insufficiency fractures. We assessed the occurrence of subsequent fractures and evaluated fracture healing in patients who either continued or discontinued MTX following the initial fracture.

RESULTS

We identified 33 patients with characteristic MTXO lower limb insufficiency fractures. The mean MTX dose was 20 ± 5.9 mg weekly with average treatment duration of 10.7 ± 6.2 years. MTX was continued in 21 out of 32 patients following the initial insufficiency fracture. Almost all patients (95.2%) who continued methotrexate sustained either further insufficiency (67%) or major osteoporotic (33%) fractures. There were significantly fewer fractures (3 out of 11, 27.3%) in the group that stopped MTX after the initial insufficiency fracture (χ2 = (1, N = 32) = 13.4; P < .001). A Kaplan-Meier analysis showed that significantly increased number of patients who continued MTX after the initial insufficiency fracture sustained a further fracture over time when compared to patients who stopped methotrexate (P = .042). Discontinuation of MTX was associated with greater clinical improvement in pain (77.8% vs 36.4%, P = .036) and weight-bearing capacity (71.4% vs 22.7%, P = .030) during fracture healing.

CONCLUSIONS

In patients with MTXO insufficiency fractures, continuation of MTX is associated with a high risk of further fracture. It is important to recognise such insufficiency fractures and stop MTX to minimise the future fracture risk.

Atractylenolide I Attenuates Glucocorticoid-Induced Osteoporosis via Inhibiting NF-κB Signaling Pathway

Long-term treatment with glucocorticoids significantly impacts bone health, with glucocorticoid-induced osteoporosis (GIOP) being the most prevalent consequence. Previous studies have established that Atractylenolide I (Atr I) possesses anti-inflammatory, antioxidant and anti-tumor properties, however, its specific effects on osteoclastogenesis and GIOP are still unclear. In this study, our in vitro results revealed that Atr I inhibited RANKL-stimulated osteoclast differentiation in a dose-dependent manner, disrupted the structure of the F-actin belt in mature osteoclasts, blocked RANKL-induced ROS production, and suppressed the expression of osteoclast-associated genes. Mechanistically, the findings indicated that Atr I inhibited the RANKL-induced activation of the NF-κB signaling pathway. In vivo, the micro-CT, bone histomorphometric analysis and histological data demonstrated that Dex administration led to significant bone loss, accompanied by a considerable increase in the number of osteoclasts on the bone surface. Conversely, treatment with Atr I effectively prevented these Dex-induced alterations. Taken together, this study suggests that Atr I may hold potential as a therapeutic agent for the treatment of GIOP.

Denosumab in the Management of Glucocorticoid-Induced Osteoporosis: Long-Term Efficacy and Secondary Fracture Outcomes

Objectives: Osteoporosis is a common complication in patients undergoing long-term corticosteroid therapy, particularly those with rheumatological and immunological conditions. Denosumab has shown potential in enhancing bone density and reducing fracture risk in such patients. This study evaluates the effectiveness of denosumab in osteoporosis management among corticosteroid-treated individuals. Methods: Between 2013 and 2022, 390 osteoporosis patients who received denosumab (60 mg subcutaneously every 6 months) for ≤18 months were enrolled. Patients were categorized based on corticosteroid use, and age-matching was applied to ensure comparability. Bone mineral density (BMD) and trabecular bone score (TBS) at the lumbar spine and femoral neck were assessed, and secondary fractures during the follow-up period were recorded. Results: Over the 18-month follow-up, both groups showed improvements in lumbar spine T-scores. The corticosteroid group increased from -2.1 ± 1.2 to -2.0 ± 1.3 (p < 0.001), while the non-corticosteroid group improved from -2.6 ± 1.2 to -2.4 ± 1.2 (p = 0.003). However, logistic regression analysis revealed that corticosteroid use remained a significant risk factor for secondary fractures (odds ratio: 1.69; 95% confidence interval: 1.11-2.56, p = 0.014), despite denosumab treatment. Conclusions: This retrospective study observed stabilization and a modest increase in BMD and TBS among corticosteroid users. Although differences in secondary fractures persisted between groups, denosumab shows potential for managing corticosteroid-induced osteoporosis. The study's focus on Taiwanese patients limits its generalizability, and future research should include diverse populations to enhance applicability.

Reducing PDK4 level constitutes a pivotal mechanism for glucocorticoids to impede osteoblastic differentiation through the enhancement of ferroptosis in mesenchymal stem cells

BACKGROUND

This study mainly explores the possible role and mechanism of pyruvate dehydrogenase kinase 4 (PDK4) in the onset and development of Glucocorticoid-induced osteoporosis (GIOP), and seeks potential targets for the treatment of GIOP.

METHODS

Mesenchymal stem cells (MSCs) were treated with osteogenic induction medium. An in vitro osteogenic damage model was established by exposing MSCs to a high concentration (10- 6 M) of dexamethasone (DEX). Osteogenic markers were measured with real-time quantitative polymerase chain reaction, western blot, alkaline phosphatase staining, and Alizarin Red S staining. Ferroptosis markers were assessed through reactive oxygen species (ROS) fluorescent probe, transmission electron microscopy, and measurement of malondialdehyde (MDA). The potential mechanism was investigated using RT-qPCR, western blot, lysosomal probes, molecular docking, and other analytical approaches. The role of PDK4 was validated by using a GIOP rat model, micro-computed tomography and Masson's trichrome staining.

RESULTS

High concentrations (10- 6 M) of DEX inhibited osteogenic differentiation in C3H10T1/2 cells, and PDK4 exhibited the opposite effect. PDK4 partially reversed the osteogenic inhibitory effect of DEX both in vivo and in vitro. DEX caused mitochondrial shrinkage and disappearance of cristae in C3H10T1/2 cells, as well as an increase in total iron, ROS, MDA contents, and the level of ferroptosis key factors. These changes were partially weakened by PDK4. The ferroptosis inhibitor ferrostatin-1 partially blocked the inhibitory effect of DEX, while ferroptosis inducer RSL3 inhibited osteogenic differentiation and weakened the reversal effect of PDK4. DEX reduced the protein level of PDK4, which was partially weakened by Bafilomycin A1. The molecular docking results showed that DEX can directly bind with PDK4.

CONCLUSION

PDK4 can enhance the osteogenic differentiation ability of MSCs and bone mass of GIOP rats. DEX may promote the degradation of PDK4 via lysosome pathway, through which to weaken the osteogenic ability of MSCs by increasing ferroptosis. PDK4 may become a potential target for improving GIOP.

Supplementation with carnosine, a food-derived bioactive dipeptide, alleviates dexamethasone-induced oxidative stress and bone impairment via the NRF2 signaling pathway

BACKGROUND

Carnosine, a natural bioactive dipeptide derived from meat muscle, possesses strong antioxidant properties. Dexamethasone, widely employed for treating various inflammatory diseases, raises concerns regarding its detrimental effects on bone health. This study aimed to investigate the protective effects of carnosine against dexamethasone-induced oxidative stress and bone impairment, along with its underlying mechanisms, utilizing chick embryos and a zebrafish model in vivo, as well as MC3T3-E1 cells in vitro.

RESULTS

Our findings revealed that carnosine effectively mitigated bone injury in dexamethasone-exposed chick embryos, accompanied by reduced oxidative stress. Further investigation demonstrated that carnosine alleviated impaired osteoblastic differentiation in MC3T3-E1 cells and zebrafish by suppressing the excessive production of reactive oxygen species (ROS) and enhancing the activity of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPX). Moreover, mechanistic studies elucidated that carnosine promoted the expression and nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), thereby facilitating the transcription of its downstream antioxidant response elements, including heme oxyense-1 (HO-1), glutamate cysteine ligase modifier (GCLM), and glutamate cysteine ligase catalytic (GCLC) to counteract dexamethasone-induced oxidative stress.

CONCLUSION

Overall, this study underscores the potential therapeutic efficacy of carnosine in mitigating oxidative stress and bone damage induced by dexamethasone exposure, shedding light on its underlying mechanism of action by activating the NRF2 signaling pathway. © 2024 Society of Chemical Industry.

Palm Tocotrienol Activates the Wnt3a/β-Catenin Signaling Pathway, Protecting MC3T3-E1 Osteoblasts from Cellular Damage Caused by Dexamethasone and Promoting Bone Formation

Background and aim: Prolonged glucocorticoid (GC) treatment increases oxidative stress, triggers apoptosis of osteoblasts, and contributes to osteoporosis. Tocotrienol, as an antioxidant, could protect the osteoblasts and preserve bone quality under glucocorticoid treatment. From this study, we aimed to determine the effects of tocotrienol on MC3T3-E1 murine pre-osteoblastic cells treated with GC. Methods: MC3T3-E1 cells were exposed to dexamethasone (150 µM), with or without palm tocotrienol (PTT; 0.25, 0.5, and 1 µg/mL). Cell viability was measured by the MTS assay. Alizarin Red staining was performed to detect calcium deposits. Cellular alkaline phosphatase activity was measured to evaluate osteogenic activity. The expression of osteoblastic differentiation markers was measured by an enzyme-linked immunoassay. Results: Enhanced matrix mineralization was observed in the cells treated with 0.5 µg/mL PTT, especially on day 18 (p < 0.05). The expression of Wnt3a, β-catenin, collagen 1α1, alkaline phosphatase, osteocalcin, low-density lipoprotein receptor-related protein 6, and runt-related transcription factor-2 were significantly increased in the PTT-treated groups compared to the vehicle control group, especially at 0.5 µg/mL of PTT (p < 0.05) and on day 6 of treatment. Conclusions: PTT maintains the osteogenic activity of the dexamethasone-treated osteoblasts by promoting their differentiation.

Rheumatoid arthritis and the risk of fracture: A Mendelian randomization study

Observational epidemiological studies indicate a higher fracture incidence in rheumatoid arthritis (RA) patients compared to the general population. However, the causal relationship between RA and fracture risk, particularly traumatic and osteoporotic fractures, is not well established. We performed Mendelian randomization (MR) analysis to evaluate the causal relationship between RA and fracture risk. We performed a MR analysis using summary statistics from genome-wide association studies to investigate the causal association between RA and the risk of traumatic fractures at 9 sites and 3 types of osteoporotic fractures. The primary analysis used inverse-variance weighting, supplemented by MR-Egger regression and other methods to assess causal relationships and sensitivity analyses, including heterogeneity and pleiotropy assessments, using R software with appropriate packages. The inverse-variance weighting results demonstrated a causal relationship between genetically predicted RA and an elevated risk of fractures, particularly traumatic fractures of the long bones and osteoporotic fractures, including fractures of shoulder and upper arm (odds ratio [OR] = 1.041, 95% confidence interval [CI]: 1.020-1.062, P = 9.06e-05), fractures of forearm (OR = 1.026, 95% CI: 1.007-1.044, P = .006), fracture of femur (OR = 1.036, 95% CI: 1.009-1.064, P = .009), fractures of lower leg, including joint (OR = 1.031, 95% CI: 1.016-1.047, P = 6.38e-05), fractures of rib(s), sternum, and thoracic vertebrae (OR = 1.041, 95% CI: 1.018-1.064, P = 4.08e-04), osteoporotic with pathological features (OR = 1.128, 95% CI: 1.071-1.188, P = 5.54e-06), postmenopausal osteoporotic with pathological features (OR = 1.060, 95% CI: 1.002-1.123, P = .044), and drug-induced osteoporotic with pathological features (OR = 1.255, 95% CI: 1.124-1.400, P = 5.02e-05). This study highlights the genetic causal link between RA and an increased risk of traumatic and osteoporotic fractures, presenting a new direction for future exploration of the mechanisms underlying RA-related fractures.

Evaluation of resveratrol's protective effect on hydrocortisone-induced growth inhibition in the peripubertal rat epiphyseal plate

OBJECTIVE

Chronic use of glucocorticoids during childhood can lead to a decrease in hormone release, including ACTH, GH, TSH, and LH, as well as reduced IGF-1 activity. This can result in osteoporotic changes and hinder growth in height. Resveratrol, an antioxidant with phytoestrogen properties, may improve bone health by increasing bone mineral density in postmenopausal women. It has been shown that resveratrol promotes osteoblastic bone formation and reduces osteoclastic resorption. We aimed to investigate the protective effects of resveratrol on the growth inhibition of the epiphyseal plate induced by hydrocortisone in peripubertal Wistar Albino rats.

METHODS

Rats were randomized into 6 groups and treated with hydrocortisone (10 mg/kg/day) and resveratrol (10-50-100 mg/kg/day) for 10 days after a standard AP tibia radiograph was taken. Blood and tibia bones were collected and evaluated for bone biomarkers (osteopontin, sclerostin), histopathological measures, and apoptosis markers.

RESULTS

Subcutaneous administration of hydrocortisone for 10 days significantly reduced tibia linear growth, as evaluated by radiography (23.4 % vs. 15.1 %, p<0.001). In the group that received 50 mg/kg/day of resveratrol and 10 mg/kg/day of hydrocortisone together, the tibia growth inhibition disappeared both radiographically and histologically. High-dose resveratrol (100 mg/kg/day) significantly reduced plasma sclerostin (p<0.001) and increased osteopontin blood levels (p<0.05) compared to the control group.

CONCLUSION

The inhibitory effect of 10 mg/kg/day hydrocortisone on tibia bone was reversed with 50 mg/kg/day oral resveratrol. Resveratrol's phytoestrogen property is thought to accelerate chondrocyte cellular senescence, counteracting hydrocortisone's inhibitory effect on gonadotropin secretion and senescence.

Neuroendocrinology of bone

The past decade has witnessed significant advances in our understanding of skeletal homeostasis and the mechanisms that mediate the loss of bone in primary and secondary osteoporosis. Recent breakthroughs have primarily emerged from identifying disease-causing mutations and phenocopying human bone disease in rodents. Notably, using genetically-modified rodent models, disrupting the reciprocal relationship with tropic pituitary hormone and effector hormones, we have learned that pituitary hormones have independent roles in skeletal physiology, beyond their effects exerted through target endocrine glands. The rise of follicle-stimulating hormone (FSH) in the late perimenopause may account, at least in part, for the rapid bone loss when estrogen is normal, while low thyroid-stimulating hormone (TSH) levels may contribute to the bone loss in thyrotoxicosis. Admittedly speculative, suppressed levels of adrenocorticotropic hormone (ACTH) may directly exacerbate bone loss in the setting of glucocorticoid-induced osteoporosis. Furthermore, beyond their established roles in reproduction and lactation, oxytocin and prolactin may affect intergenerational calcium transfer and therefore fetal skeletal mineralization, whereas elevated vasopressin levels in chronic hyponatremic states may increase the risk of bone loss.. Here, we discuss the interaction of each pituitary hormone in relation to its role in bone physiology and pathophysiology.

Poor bone health in Duchenne muscular dystrophy: a multifactorial problem beyond corticosteroids and loss of ambulation

Duchenne muscular dystrophy (DMD) is a progressive, fatal muscle wasting disease caused by X-linked mutations in the dystrophin gene. Alongside the characteristic muscle weakness, patients face a myriad of skeletal complications, including osteoporosis/osteopenia, high susceptibility to vertebral and long bone fractures, fat embolism post-fracture, scoliosis, and growth retardation. Those skeletal abnormalities significantly compromise quality of life and are sometimes life-threatening. These issues were traditionally attributed to loss of ambulation and chronic corticosteroid use, but recent investigations have unveiled a more intricate etiology. Factors such as vitamin D deficiency, hormonal imbalances, systemic inflammation, myokine release from dystrophic muscle, and vascular dysfunction are emerging as significant contributors as well. This expanded understanding illuminates the multifaceted pathogenesis underlying skeletal issues in DMD. Present therapeutic options are limited and lack specificity. Advancements in understanding the pathophysiology of bone complications in DMD will offer promising avenues for novel treatment modalities. In this review, we summarize the current understanding of factors contributing to bone problems in DMD and delineate contemporary and prospective multidisciplinary therapeutic approaches.

Waist circumference, among metabolic syndrome components, predicts degraded trabecular bone score: a retrospective study of a female population from the 2005-2008 NHANES cohorts

Background

Osteoporosis and metabolic syndrome (MetS) are conditions associated with ageing and chronic inflammation; among MetS' components, visceral obesity has been correlated to low bone mineral density in postmenopausal women. However, data on an increased fracture risk in MetS are still contrasting. The trabecular bone score (TBS) is an indicator of bone quality and a potential predictive factor for fractures. We aim to explore the relationship between MetS components and TBS.

Methods

we analyzed data from 3962 women in the 2005-2006 and 2007-2008 NHANES cohorts, for whom a valid TBS value was available. All analyses were adjusted for the principal risk factors of altered bone metabolism.

Results

An inverse significant association was observed between TBS and most of the MetS variables investigated, with the strongest correlation found with waist circumference (WC) (P <0.001). WC represented the major predictor of degraded TBS (P <0.001), in adjusted models considering age, 25(OH)Vitamin D, smoke and insulin resistance. Increased WC was significantly associated with the presence of bone fractures at the logistic regression analysis (P = 0.001) in all study participants and in the subgroup of women ≤50 years old after adjustment for potential confounders (P = 0.006).

Conclusion

This study, using a large sample of women, found a negative association of MetS on bone health, mainly driven by visceral obesity.

USP10-mediated deubiquitination of NR3C1 regulates bone homeostasis by controlling CST3 expression

Dysregulated bone homeostasis contributes to multiple diseases including osteoporosis (OP). In this study, osteoporotic mice were successfully generated using ovariectomy to investigate the role of nuclear receptor subfamily 3 group C member 1 (NR3C1) in OP. NR3C1, identified as a significantly upregulated gene in OP using bioinformatic tools, was artificially downregulated in osteoporotic mice. NR3C1 expression was significantly elevated in the femoral tissues of osteoporotic patients, and downregulation of NR3C1 alleviated bone loss and restored bone homeostasis in osteoporotic mice, as manifested by increased ALP- and OCN-positive cells and reduced RANKL/OPG ratio. Downregulation of NR3C1 inhibited osteoclastic differentiation of RAW264.7 cells and mouse bone marrow-derived macrophages (BMDM) and promoted osteogenic differentiation of MC3T3-E1 cells. The transcription factor NR3C1 bound to the cystatin-3 (CST3) promoter to repress its transcription in both RAW264.7 and MC3T3-E1 cells. The downregulation of CST3 reversed the protective effect of NR3C1 downregulation against OP. Ubiquitin-specific-processing protease 10 (USP10)-mediated deubiquitination of NR3C1 improved NR3C1 stability. Downregulation of USP10 inhibited osteoclastic differentiation of RAW264.7 cells and BMDM while promoting osteogenic differentiation of MC3T3-E1 cells. Taken together, USP10-mediated deubiquitination of NR3C1 regulates bone homeostasis by controlling CST3 transcription, providing an attractive therapeutic strategy to alleviate OP.

Characterization and Predictors of Fractures Following Hematopoietic Stem Cell Transplantation

CONTEXT

Bone loss and fractures are common and serious complications following hematopoietic stem cell transplantation (HSCT), and identifying risk predictors for fractures in transplant recipients remains challenging. The Taiwan Bone Marrow Donation Center is the largest databank of donors in Asia. However, no population-based studies have yet been conducted in Asia to accurately assess the risk of fractures.

OBJECTIVE

The aims of this study were to determine the incidence and risk factors for fractures in HSCT recipients.

METHODS

We conducted a retrospective cohort study of patients older than 18 years who received a HSCT from January 1, 2003 to September 30, 2015, using the Taiwan National Health Insurance Research Database. Fractures following HSCT were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes. Cox regression analysis was used to identify risk factors for fractures.

RESULTS

A total of 3327 patients underwent a HSCT, of whom 126 (3.8%) had a fracture after HSCT. The cumulative incidence of fractures was 5.3% at 5 years, and 10.8% at 10 years. Multivariable analysis showed that a fracture in the 3 years prior to transplant (HR = 3.79; 95% CI, 2.39-6.03) was associated with a higher risk of fractures post HSCT. With a daily dose equivalent of more than 0.50-3.75 mg, more than 3.75-15.23 mg, and more than 15.23 mg prednisolone, the risk of fractures increased by 1.70-fold (95% CI, 1.07-2.71), 2.23-fold (95% CI 1.32-3.76), and 2.93-fold (95% CI, 1.43-6.01), respectively.

CONCLUSION

Regular screening to monitor bone loss should be initiated early, and counseling about the importance of general preventive measures for bone loss is warranted in HSCT recipients with a prior fracture and mean daily dose of steroids more than 0.50 mg.

Mechanism of modified danggui buxue decoction in glucocorticoid-induced osteoporosis: A discussion based on network pharmacology and molecular docking

Objective

Glucocorticoid-induced osteoporosis (GIOP) represents a major complication arising from the long-term use of glucocorticoids, which are widely prescribed for various inflammatory and autoimmune conditions. Despite its prevalence, the current therapeutic options for GIOP are limited in terms of efficacy, safety profiles, and patient compliance. The Modified Danggui Buxue Decoction (DGBXD), a traditional Chinese herbal formulation, has shown promise in preliminary studies for its potential osteoprotective effects. The present study aimed to explore the mechanistic underpinnings of DGBXD's action on GIOP using network pharmacology and molecular docking approaches, bridging traditional medicine with modern pharmacological insights.

Method

Network pharmacology is applied to screen drug-active compounds and potential core target proteins for disease treatment and to explore the drugs' therapeutic mechanisms.

Result

Altogether, 78 DGBXD active compounds and 223 DGBXD-related, 146 component-disease common, and 2168 GIOP-associated target genes were obtained. The PPI network had 43 nodes and 462 edges, and a total of 10 core target genes, including TP53, JUN and MAPK3, were identified. The results of the GO enrichment analysis implied that DGBXD might participate in biological activities, including responses to oxidative stress and nutrient levels. The outcomes of the KEGG pathway enrichment analysis showed that DGBXD may treat GIOP through TNF, IL-17, and phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathways. Based on to the molecular docking results, biologically active compounds (beta-carotene, formononetin, luteolin, and isorhamnetin) exhibited good binding to AKT1 and ESR1.

Conclusion

DGBXD may aid in GIOP treatment by modulating multiple therapeutic targets and signaling pathways.

Long-Term Bone Density Changes and Fracture Risk in Myasthenia Gravis: Implications for FRAX® Tool Application

Myasthenia gravis (MG) patients often require long-term glucocorticoid therapy, which may affect bone health. This study aimed to assess long-term changes in bone mineral density (BMD), evaluate osteoporotic fracture incidence, and examine the relationship between MG-specific factors and bone health outcomes over a 10-year period. This single-center, prospective cohort study included 28 MG patients. BMD, T-scores, Z-scores, and bone turnover markers were measured at baseline. FRAX® scores were calculated and adjusted for glucocorticoid dose. Fracture occurrence was monitored for over 10 years. Five (17.9%) patients experienced major osteoporotic fractures during follow-up. The fracture group had significantly lower baseline BMD and T-scores than the no-fracture group. Baseline FRAX® scores for major osteoporotic fracture risk were significantly higher in the fracture group (median 19.0% vs. 5.7%, p = 0.001). The fracture group progressed from osteopenia at baseline to osteoporosis by the end of this study. This study highlights the importance of early and regular bone health assessments in MG patients, particularly those receiving long-term glucocorticoid therapy. The FRAX® tool may be valuable for fracture risk stratification in this population. These findings can inform clinical practice and improve long-term management strategies for MG patients who are at risk of osteoporotic fractures.

The comprehensive incidence and risk factors of fracture in kidney transplant recipients: A meta-analysis

AIM

Kidney transplant recipients are at high risk of fracture due to many factors such as nutritional status, hyperparathyroidism, acidosis and steroid administration. The current meta-analysis aimed to comprehensively analyse the incidence and risk factors of fracture in kidney transplant recipients.

METHODS

A systematic search on Embase, Web of Science, PubMed and Cochrane Library until November 2023 was performed. RStudio software was used to analyse data.

RESULTS

Twenty-eight eligible studies containing 310 530 kidney transplant recipients were included in the analysis. The pooled incidence of fracture was 10% (95% confidence interval [CI]: 7%-13%) generally. When divided by regions, it was further observed that the pooled incidence of fracture was 13% (95% CI: 9%-17%) in Europe, 11% (95% CI: 6%-16%) in North America, 7% (95% CI: 3%-11%) in Asia. Regarding the risk factors, pooled analysis revealed that age of recipient (hazard ratio [HR] = 1.50, 95% CI: 1.17-1.91), female sex (HR = 1.45, 95% CI: 1.36-1.53), pretransplantation diabetes (HR = 1.76, 95% CI: 1.58-1.97), pretransplantation fracture history (HR = 2.28, 95% CI: 1.86-2.78), dialysis duration (HR = 1.09, 95% CI: 1.01-1.17) and deceased donor (HR = 1.21, 95% CI: 1.05-1.39) related to higher risk of fracture. The general quality of included studies was acceptable, and no publication bias existed except for the analysis between age of recipient and fracture incidence; further trim and fill method indicated age of recipient showed a correlation trend with the fracture incidence without the statistical significance.

CONCLUSION

The pooled incidence of fracture reaches 10% in kidney transplant recipients, which relates to age of recipient, female sex, pretransplantation diabetes or fracture history, dialysis duration and decease donor.

Chronic Oral Corticosteroid Use and 10-Year Incidence of Major Complications Following Total Knee Arthroplasty

BACKGROUND

Oral corticosteroids are the primary treatment for several autoimmune conditions. The risk of long-term implant, bone health, and infectious-related complications in patients taking chronic oral corticosteroids before total knee arthroplasty (TKA) is unknown. We compared the 10-year cumulative incidence of revision, periprosthetic joint infection (PJI), fragility fracture (FF), and periprosthetic fracture following TKA in patients who had and did not have preoperative chronic oral corticosteroid use.

METHODS

A retrospective cohort analysis was conducted using a national database. Primary TKA patients who had chronic preoperative oral corticosteroid use were identified using Current Procedural Terminology and International Classification of Disease 9 and 10 codes. Exclusion criteria included malignancy, osteoporosis treatment, trauma, and < 2-year follow-up. Primary outcomes were 10-year cumulative incidence and hazard ratios (HRs) of all-cause revision (ACR), aseptic revision, PJI, FF, and periprosthetic fracture. A Kaplan-Meier analysis and a multivariable Cox proportional hazards model were utilized. Overall, 611,596 patients were identified, and 5,217 (0.85%) were prescribed chronic corticosteroids. There were 10,000 control patients randomly sampled for analysis.

RESULTS

Corticosteroid patients had significantly higher 10-year HR of FF (HR; 95% confidence interval); P value (1.47; 1.34 to 1.62; P < .001)], ACR (1.21; 1.05 to 1.40; P = .009), and PJI (1.30; 1.01 to 1.69; P = .045) when compared to the control.

CONCLUSIONS

Patients prescribed preoperative chronic oral corticosteroids had higher risks of ACR, PJI, and FF within 10 years following TKA compared to patients not taking corticosteroids. This information can be used by surgeons during preoperative counseling to educate this high-risk patient population about their increased risk of postoperative complications.

Loss of BACH1 improves osteogenic differentiation in glucocorticoid-induced hBMSCs through restoring autophagy

BACKGROUND

Glucocorticoid-induced osteoporosis (GIOP) is the most common type of secondary osteoporosis. Recently, autophagy has been found to be related with the development of various diseases, including osteoporosis and osteoblast differentiation regulations. BTB and CNC homology 1 (BACH1) was a previously confirmed regulator for osteoblast differentiation, but whether it's could involve in glucocorticoid-induced human bone mesenchymal stem cells (hBMSCs) differentiation and autophagy regulation remain not been elucidated.

METHODS

hBMSCs were identified by flow cytometry method, and its differentiation ability were measured by ARS staining, oil O red, and Alcian blue staining assays. Gene and proteins were quantified via qRT-PCR and western blot assays, respectively. Autophagy activity was determined using immunofluorescence. ChIP and dual luciferase assay validated the molecular interactions.

RESULTS

The data revealed that isolated hBMSCs exhibited positive of CD29/CD44 and negative CD45/CD34. Moreover, BACH1 was abated gradually during osteoblast differentiation of hBMSCs, while dexamethasone (Dex) treatment led to BACH1 upregulation. Loss of BACH1 improved osteoblast differentiation and activated autophagy activity in Dex-challenged hBMSCs. Autophagy-related proteins (ATG3, ATG4, ATG5, ATG7, ATG12) were repressed after Dex treatment, while ATG3, ATG7 and BECN1 could be elevated by BACH1 knockdown, especially ATG7. Moreover, BACH1 could interact ATG7 promoter region to inhibit its transcription. Co-inhibition of ATG7 greatly overturned the protective roles of BACH1 loss on osteoblast differentiation and autophagy in Dex-induced hBMSCs.

CONCLUSION

Taken together, our results demonstrated that silencing of BACH1 mitigated Dex-triggered osteogenic differentiation inhibition by transcriptionally activating ATG7-mediated autophagy, suggesting that BACH1 may be a therapeutic target for GIOP treatment.

Changes in RANKL, OPG, and 25(OH)D Levels in Children with Leukemia from Diagnosis to Remission

BACKGROUND

The receptor activator of the nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) pathway is a determining pathway in the balance between bone formation and resorption, and disruptions in this complex can affect bone metabolism.

METHODS

This study analyzes the changes in RANKL, OPG, and 25(OH)D levels; the RANKL/OPG ratio; and other bone turnover markers (BTMs) from diagnosis to complete remission in children with acute lymphoblastic leukemia (ALL). This is a prospective observational cohort study, carried out at the Instituto Mexicano del Seguro Social, Mexico City, including 33 patients (4-17 years) with newly diagnosed B-cell ALL. The patients were treated with the HP09 chemotherapy protocol. Children who had previously been treated with corticosteroids were excluded. A peripheral blood sample at diagnosis and remission was collected to determine the 25(OH)D and BTM concentrations.

RESULTS

Increased RANKL (p = 0.001) and osteocalcin (p < 0.001) levels and RANKL/OPG ratio (<0.001) and a decreased OPG level (p = 0.005) were observed at remission, predominantly in the high-risk (HR) relapse and vitamin D deficiency groups. A negative association between RANKL and OPG (r = -0.454, p = 0.008) was observed.

CONCLUSIONS

we suggest that the RANKL/OPG ratio could serve as a bone remodeling marker in ALL patients.

Exploring bone density analysis on routine CT scans as a tool for opportunistic osteoporosis screening

The primary aim of this study was to evaluate computed tomography (CT)-based bone density analysis at the level of thoracic vertebra 12 (Th12) as a screening method for decreased bone density in patients admitted to the intensive care unit (ICU). Interobserver variability was analyzed. Secondary aims were to assess the prevalence of CT-based low bone density upon ICU admission in a cohort of COVID-19 patients and to assess the potential effect of long-term ICU stay on bone density in these patients. Retrospective single-center cohort study. ICU of the Leiden University Medical Center (LUMC), the Netherlands. Patients admitted to the ICU of the LUMC between March 1st, 2020 and February 1st, 2022 with a diagnosis of COVID-19, and a length of ICU stay of ≥ 21 days. In the included patients both baseline chest CT scans (obtained upon ICU admission) and follow-up chest CT scans (obtained ≥ 21 days after ICU admission) were available for analysis. A total of 118 CT scans in 38 patients were analyzed. There was a good interobserver variability, with an overall mean absolute difference (between measurements of three observers) of 9.7 Hounsfield Units (HU) and an intraclass correlation coefficient (ICC) of 0.93 (95% CI 0.88-0.96). The effect of intravenous contrast administration on bone density measurements was small (+ 7.5 HU (95% CI 3.4-11.5 HU)) higher in contrast enhanced CT images compared to non contrast enhanced CT images). Thirty-seven percent of patients had a bone density < 140 HU, suggestive of osteoporosis. No significant difference was found between bone density upon ICU admission and bone density at follow-up (≥ 21 days after ICU admission). Vertebral CT-based bone density analysis using routine CT scans is an easily applicable method to identify ICU patients with decreased bone density, which could enable enrollment in osteoporosis prevention programs. A high prevalence of low bone density was found in our cohort of ICU patients. There were no changes observed in bone density between baseline and follow-up measurements.

Glucocorticoid prescribing in neurology

Glucocorticoids are commonly used for neurological disorders, but they can have significant adverse effects, including adrenal insufficiency, hyperglycaemia, osteoporosis and increased infection risk. Long-term use of corticosteroids requires the prescriber to plan risk mitigation, including monitoring and often coprescribing. This article highlights the potential risks of corticosteroid prescribing and draws together up-to-date guidance with multispecialty input to clarify ways of reducing those risks. We discuss home blood glucose monitoring and consider a steroid safety checklist to promote safer steroid prescribing.

Osteostaticytes: A novel osteoclast subset couples bone resorption and bone formation

BACKGROUND

Osteomyelitis (OM) is an inflammatory condition of bone characterized by cortical bone devascularization and necrosis. Dysregulation of bone remodelling is triggered by OM. Bone remodelling is precisely coordinated by bone resorption and formation via a reversal phase. However, the cellular and molecular mechanisms underlying bone remodelling failure after osteomyelitis remain elusive.

METHODS

To elucidate the cellular and molecular mechanism underlying bone healing after osteomyelitis, we employed single-cell RNA sequencing (scRNA-seq) to depict the atlas of human cortical bone in normal, infected and reconstructed states. Dimensionality reduction by t-stochastic neighbourhood embedding (t-SNE) and graph-based clustering were applied to analyse the detailed clusters of osteoclast lineages. After trajectory analysis of osteoclast lineages over pseudotime, real-time PCR and immunofluorescence (IF) staining were applied to identify marker gene expression of various osteoclast lineages in the osteoclast induction model and human bone sections, respectively. The potential function and communication of osteoclasts were analysed via gene set enrichment analysis (GSEA) and CellChat. The chemotactic ability of mesenchymal stem cells (MSCs) and osteoclast lineage cells in various differentiation states was determined by transwell assays and coculture assays. The effects of various osteoclast lineages on the osteogenic differentiation potential of MSCs were also determined by using this coculture system. A normal mouse tibia fracture model and an osteomyelitis-related tibia fracture model were generated via injection of luciferase-labelled Staphylococcus aureus to verify the relationships between a novel osteoclast lineage and MSCs. Then, the infection was detected by a bioluminescence imaging system. Finally, immunofluorescence staining was used to detect the expression of markers of MSCs and novel osteoclast lineages in different remodelling phases in normal and infected bone remodelling models.

RESULTS

In this study, we constructed a cell atlas encompassing normal, infected, and reconstructed cortical bone. Then, we identified a novel subset at the earlier stage of the osteoclast lineage that exhibited increased expression of IDO1, CCL3, and CCL4. These IDO1highCCL3highCCL4high cells, termed osteostaticytes (OSCs), were further regarded as the reservoir of osteoclasts in the reversal phase. Notably, OSCs exhibited the highest chemotactic activity, surpassing other lineage subsets. We also discovered that cells at the earlier stage of the osteoclast lineage play a significant role in recruiting mesenchymal stem cells (MSCs). Finally, the data revealed that OSCs might be positively related to the occurrence of bone MSCs and the contribution of bone remodelling.

CONCLUSION

Collectively, our findings revealed a novel stage (OSC) within the osteoclast lineage, potentially representing elusive bone reversal cells due to its increased chemotactic ability towards MSCs and potential contribution to bone remodelling. This study provides valuable insights into the intricate mechanisms of the reversal phase during bone remodelling and unveils potential therapeutic strategies for diseases associated with bone uncoupling.

TRANSLATIONAL POTENTIAL OF THIS ARTICLE

This study identified a new subset, referred to as IDO1(plus symbol) CCL3(plus symbol) CCL4(plus symbol) osteostaticytes which displayed the highest chemotactic activity among all osteoclast lineages and may serve as reversal cells in bone remodelling. These findings offer new insights and insights for understanding bone reversal-related diseases and may serve as novel therapeutic targets for conditions such as osteomyelitis and delayed bone healing.

Impact of Bone Mineral Density and Bone Structural Properties on Postmenopausal Women With Rheumatoid Arthritis in Japan: A Cross-Sectional Study

Introduction There has been no study on bone structural properties in postmenopausal women with rheumatoid arthritis (RA) in Japan. This study investigated bone mineral density (BMD) and bone structural properties in Japanese postmenopausal women with RA. Methods The study had a cross-sectional design and included 119 postmenopausal women aged 50-80 years with RA symptoms for more than five years. BMD, trabecular bone score (TBS), and results of hip structure analysis (HSA) were measured on dual-energy X-ray absorptiometry scans. The control group consisted of 288 women aged 50-80 years without RA. The RA group and control group using bisphosphonates were compared after propensity score matching for age, body mass index, and fracture history. Women in the RA group were also compared according to the use of glucocorticoids (GCs). Results After the propensity matching score, there were no other significant differences in BMD, TBS, and HSA parameters between the RA group and the control group. In the RA group, the TBS was lower in patients on GCs than those not on GCs (1.272 vs 1.313, p=0.008). There were no other significant differences in BMD and HSA parameters between patients in the RA group according to the use of GCs. Conclusion Although there were no differences in BMD, the TBS was lower in patients on GCs than those not on GCs in the RA group. It is thus important for physicians who administer GCs to treat patients with RA to be aware of not only BMD but also TBS.

RNA-binding proteins in bone pathophysiology

Bone remodelling is a highly regulated process that maintains mineral homeostasis and preserves bone integrity. During this process, intricate communication among all bone cells is required. Indeed, adapt to changing functional situations in the bone, the resorption activity of osteoclasts is tightly balanced with the bone formation activity of osteoblasts. Recent studies have reported that RNA Binding Proteins (RBPs) are involved in bone cell activity regulation. RBPs are critical effectors of gene expression and essential regulators of cell fate decision, due to their ability to bind and regulate the activity of cellular RNAs. Thus, a better understanding of these regulation mechanisms at molecular and cellular levels could generate new knowledge on the pathophysiologic conditions of bone. In this Review, we provide an overview of the basic properties and functions of selected RBPs, focusing on their physiological and pathological roles in the bone.

Protein kinase G2 activation restores Wnt signaling and bone mass in glucocorticoid-induced osteoporosis in mice

Osteoporotic fractures are a major complication of long-term glucocorticoid therapy. Glucocorticoids transiently increase bone resorption, but they predominantly inhibit bone formation and induce osteocyte apoptosis, leading to bone loss. Current treatments of glucocorticoid-induced osteoporosis aim mainly at reducing bone resorption and are, therefore, inadequate. We previously showed that signaling via the NO/cGMP/protein kinase G pathway plays a key role in skeletal homeostasis. Here, we show that pharmacological PKG activation with the guanylyl cyclase-1 activator cinaciguat or expression of a constitutively active, mutant PKG2R242Q restored proliferation, differentiation, and survival of primary mouse osteoblasts exposed to dexamethasone. Cinaciguat treatment of WT mice or osteoblast-specific expression of PKG2R242Q in transgenic mice prevented dexamethasone-induced loss of cortical bone mass and strength. These effects of cinaciguat and PKG2R242Q expression were due to preserved bone formation parameters and osteocyte survival. The basis for PKG2's effects appeared to be through recovery of Wnt/β-catenin signaling, which was suppressed by glucocorticoids but critical for proliferation, differentiation, and survival of osteoblast-lineage cells. Cinaciguat reduced dexamethasone activation of osteoclasts, but this did not occur in the PKG2R242Q transgenic mice, suggesting a minor role in osteoprotection. We propose that existing PKG-targeting drugs could represent a novel therapeutic approach to prevent glucocorticoid-induced osteoporosis.

Genetically determined type 1 diabetes mellitus and risk of osteoporosis

BACKGROUND

Observational evidence suggests that type 1 diabetes mellitus (T1DM) is associated with the risk of osteoporosis (OP). Nevertheless, it is not apparent whether these correlations indicate a causal relationship. To elucidate the causal relationship, a two-sample Mendelian randomization (MR) analysis was performed.

METHODS

T1DM data was obtained from the large genome-wide association study (GWAS), in which 6683 cases and 12,173 controls from 12 European cohorts were involved. Bone mineral density (BMD) samples at four sites were extracted from the GEnetic Factors for OSteoporosis (GEFOS) consortium, including forearm (FA) (n = 8,143), femoral neck (FN) (n = 32,735), lumbar spine (LS) (n = 28,498), and heel (eBMD) (n = 426,824). The former three samples were from mixed populations and the last one was from European. Inverse variance weighting, MR-Egger, and weighted median tests were used to test the causal relationship between T1DM and OP. A series of sensitivity analyses were then conducted to verify the robustness of the results.

RESULTS

Twenty-three independent SNPs were associated with FN-BMD and LS-BMD, twenty-seven were associated with FA-BMD, and thirty-one were associated with eBMD. Inverse variance-weighted estimates indicated a causal effect of T1DM on FN-BMD (odds ratio (OR) =1.033, 95 % confidence interval (CI): 1.012-1.054, p = 0.002) and LS-BMD (OR = 1.032, 95 % CI: 1.005-1.060, p = 0.022) on OP risk. Other MR methods, including weighted median and MR-Egger, calculated consistent trends. While no significant causation was found between T1DM and the other sites (FA-BMD: OR = 1.008, 95 % CI: 0.975-1.043, p = 0.632; eBMD: OR = 0.993, 95 % CI: 0.985-1.001, p = 0.106). No significant heterogeneity (except for eBMD) or horizontal pleiotropy was found for instrumental variables, suggesting these results were reliable and robust.

CONCLUSIONS

This study shows a causal relationship between T1DM and the risk of some sites of OP (FN-BMD, LS-BMD), allowing for continued research to discover the clinical and experimental mechanisms of T1DM and OP. It also contributes to the recommendation if patients with T1DM need targeted care to promote bone health and timely prevention of osteoporosis.

Bone health in patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are prone to reduced bone mineral density and elevated overall fracture risk. Osteopenia affects up to 40% of patients with IBD (high regional variability). Besides disease activity, IBD specialists must consider possible side effects of medication and the presence of associated diseases and extraintestinal manifestations. Osteopenia and osteoporosis remain frequent problems in patients with IBD and are often underestimated because of widely differing screening and treatment practices. Malnutrition, chronic intestinal inflammation and corticosteroid intake are the major pathophysiological factors contributing to osteoporosis. Patients with IBD are screened for osteoporosis using dual-energy X-ray absorptiometry (DXA), which is recommended for all patients with a prolonged disease course of more than three months, with repeated corticosteroid administration, aged >40 years with a high FRAX risk score or aged <40 years with multiple risk factors. From a therapeutic perspective, besides good disease control, vitamin D supplementation and glucocorticoid sparing, several specific osteological options are available: bisphosphonates, receptor activator of nuclear factor kappa-B ligand (RANKL) inhibitors (denosumab), parathyroid hormone (PTH) analogues and selective estrogen receptor modulators. This review provides an overview of the pathophysiology, diagnosis, prevention and treatment of IBD-associated bone loss.

Associations of abdominal obesity with different types of bone fractures in adults: A systematic review and dose-response meta-analysis of prospective cohort studies

Findings on the association between abdominal obesity and hip fracture were summarized in a meta-analysis in 2017; however, no study has examined the dose-response association between abdominal fat indices and hip fracture. Also, we found no meta-analysis investigating other types of bone fractures including any vertebral fractures in relation to abdominal obesity. Therefore, the present systematic review and dose-response meta-analysis of prospective cohort studies were conducted to examine the association between abdominal obesity and different types of bone fractures. A comprehensive literature search was done by searching PubMed, Scopus, Web of Science, and Google Scholar until October 2021. In total, 23 articles from prospective cohort studies with a total sample size of 3,456,631 participants were included. During the follow-up periods ranging between 4 and 26 years, 137,989 cases of bone fracture were recorded. After comparing the highest and lowest categories of abdominal fat indices, the summary relative risks (RRs) of any, hip, and vertebral fractures were 0.99 (95% CI: 0.81-1.20), 1.09 (95% CI: 0.82-1.43), and 1.18 (95% CI: 1.05-1.33), respectively, indicating a significant positive association between abdominal obesity and risk of vertebral fracture. In the non-linear dose-response analysis, abdominal obesity based on the waist-to-hip ratio (WHR) was positively associated with an increased risk of hip fracture from 0.7 to 1.1 units of WHR. In the linear analysis, a 10 cm increase in waist circumference (WC) was associated with a 3% higher risk of vertebral fracture. We found no other dose-response association for other types of bone fractures. In conclusion, abdominal obesity may be associated with a higher risk of hip and vertebral fractures.

Dual-release hydrocortisone improves body composition and the glucometabolic profile in patients with secondary adrenal insufficiency

PURPOSE

Studies have suggested improved metabolic profiles in patients with adrenal insufficiency treated with dual-release hydrocortisone (DR-HC) compared with conventional hydrocortisone (C-HC). This study investigates the effect of DR-HC compared with C-HC treatment on five health variables: diurnal salivary cortisol/cortisone, body composition, bone health, glucose metabolism, lipids, and blood pressure.

METHODS

Prospective study of 27 participants (24 men) with secondary adrenal insufficiency with measurements during stable C-HC and 16 weeks after treatment switch to DR-HC.

OUTCOMES

Diurnal salivary-cortisol/cortisone, body composition assessed by Dual-Energy X-ray absorptiometry scan, bone status indices (serum type I N-terminal procollagen [PINP], collagen type I cross-linked C-telopeptide [CTX], osteocalcin, receptor activator kappa-B [RANK] ligand, osteoprotegerin, and sclerostin), lipids, haemoglobin A1c (HbA1c), and 24-hour blood pressure.

RESULTS

After the switch to DR-HC, the diurnal salivary-cortisol area under the curve (AUC) decreased non-significantly (mean difference: -55.9 nmol/L/day, P = 0.06). The salivary-cortisone-AUC was unchanged. Late-evening salivary-cortisol and cortisone were lower (-1.6 and -1.7 nmol/L, P = 0.002 and 0.004). Total and abdominal fat mass (-1.5 and -0.5 kg, P = 0.003 and 0.02), HbA1c (-1.2 mmol/mol, P = 0.02), and osteocalcin decreased (-7.0 µg/L, P = 0.03) whereas sclerostin increased (+41.1 pg/mL, P = 0.0001). The remaining bone status indices, lipids, and blood pressure were unchanged.

CONCLUSION

This study suggests that switching to DR-HC leads to lower late-evening cortisol/cortisone exposure and a more favourable metabolic profile and body composition. In contrast, decreased osteocalcin with increasing sclerostin might indicate a negative impact on bones.

CLINICAL TRIAL REGISTRATION

EudraCT201400203932.

Ongoing impacts of childhood-onset glomerular diseases during young adulthood

BACKGROUND

Childhood-onset glomerular disease often requires ongoing treatment and follow-up into adulthood. However, few studies have analyzed the associated impact and distress experienced by patients with this condition during the transition from childhood to adolescence and adulthood.

METHODS

At three facilities, we recruited patients who developed idiopathic nephrotic syndrome or IgA nephropathy during childhood and were at least 18 years old at the time of study entry. Among them, a questionnaire-based survey was administered to patients who consented to participate, and the results were analyzed in conjunction with clinical information.

RESULTS

Data from a total of 38 patients were analyzed. Of these patients, 15 had idiopathic nephrotic syndrome and 23 had IgA nephropathy. The age of transition from pediatrics to the adult medicine department was correlated with the number of recurrences. Many patients also reported being significantly affected by exercise restrictions and physical decline associated with their diseases and medications. Various impacts, including distress, affected decision-making regarding higher education, with patients engaging in higher education at a significantly higher rate compared with the regional average (66.7% vs. 46.9%, p = 0.028).

CONCLUSION

We analyzed the impact of childhood-onset glomerular disease and distress during the transition period from pediatric to adult care. This study highlighted the significant impact of medications and exercise restrictions on patients' decisions regarding higher education. Future prospective studies will be needed to examine patients' distress in more detail and establish management approaches to enhance patient quality of life.

Dehydrozaluzanin C- derivative protects septic mice by alleviating over-activated inflammatory response and promoting the phagocytosis of macrophages

Host-directed therapy (HDT) is a new adjuvant strategy that interfere with host cell factors that are required by a pathogen for replication or persistence. In this study, we assessed the effect of dehydrozaluzanin C-derivative (DHZD), a modified compound from dehydrozaluzanin C (DHZC), as a potential HDT agent for severe infection. LPS-induced septic mouse model and Carbapenem resistant Klebsiella pneumoniae (CRKP) infection mouse model was used for testing in vivo. RAW264.7 cells, mouse primary macrophages, and DCs were used for in vitro experiments. Dexamethasone (DXM) was used as a positive control agent. DHZD ameliorated tissue damage (lung, kidney, and liver) and excessive inflammatory response induced by LPS or CRKP infection in mice. Also, DHZD improved the hypothermic symptoms of acute peritonitis induced by CRKP, inhibited heat-killed CRKP (HK-CRKP)-induced inflammatory response in macrophages, and upregulated the proportions of phagocytic cell types in lungs. In vitro data suggested that DHZD decreases LPS-stimulated expression of IL-6, TNF-α and MCP-1 via PI3K/Akt/p70S6K signaling pathway in macrophages. Interestingly, the combined treatment group of DXM and DHZD had a higher survival rate and lower level of IL-6 than those of the DXM-treated group; the combination of DHZD and DXM played a synergistic role in decreasing IL-6 secretion in sera. Moreover, the phagocytic receptor CD36 was increased by DHZD in macrophages, which was accompanied by increased bacterial phagocytosis in a clathrin- and actin-dependent manner. This data suggests that DHZD may be a potential drug candidate for treating bacterial infections.

Predictors of bone mineral density in patients receiving glucocorticoid replacement for Addison's disease

PURPOSE

Patients receiving long-term glucocorticoid (GC) treatment are at risk of osteoporosis, while bone effects of substitution doses in Addison's disease (AD) remain equivocal. The project was aimed to evaluate serum bone turnover markers (BTMs): osteocalcin, type I procollagen N-terminal propeptide (PINP), collagen C-terminal telopeptide (CTX), sclerostin, DKK-1 protein, and alkaline phosphatase (ALP) in relation to bone mineral density (BMD) during GC replacement.

METHODS

Serum BTMs and hormones were assessed in 80 patients with AD (22 males, 25 pre- and 33 postmenopausal females) on hydrocortisone (HC) substitution for ≥3 years. Densitometry with dual-energy X-ray absorptiometry covered the lumbar spine (LS) and femoral neck (FN).

RESULTS

Among BTMs, only PINP levels were altered in AD. BMD Z-scores remained negative except for FN in males. Considering T-scores, osteopenia was found in LS in 45.5% males, 24% young and 42.4% postmenopausal females, while osteoporosis in 9.0%, 4.0% and 21.1%, respectively. Lumbar BMD correlated positively with body mass (p = 0.0001) and serum DHEA-S (p = 9.899 × 10-6). Negative correlation was detected with HC dose/day/kg (p = 0.0320), cumulative HC dose (p = 0.0030), patient's age (p = 1.038 × 10-5), disease duration (p = 0.0004), ALP activity (p = 0.0041) and CTX level (p = 0.0105). However, only age, body mass, ALP, serum CTX, and sclerostin remained independent predictors of LS BMD.

CONCLUSION

Standard HC substitution does not considerably accelerate BMD loss in AD patients and their serum BTMs: CTX, osteocalcin, sclerostin, DKK-1, and ALP activity remain within the reference ranges. Independent predictors of low lumbar spine BMD, especially ALP activity, serum CTX and sclerostin, might be monitored during GC substitution.

The Impact of Non-alcohol Fatty Liver Disease on Bone Mineral Density is Mediated by Sclerostin by Mendelian Randomization Study

Non-alcoholic fatty liver disease (NAFLD) has been found to be associated with osteoporosis (OP) in observational studies. However, the precise causal relationship between NAFLD and OP remains unclear. Here, we used Mendelian randomization (MR) to explore the causal relationship. We selected NAFLD-related single-nucleotide polymorphisms from a genome-wide meta-analysis (8434 cases and 434,770 controls) as instrumental variants. We used inverse variance weighted analysis for the primary MR analysis. Furthermore, we used similar methodologies in parallel investigations of other chronic liver diseases (CLDs). We performed sensitivity analyses to ensure the reliability of the results. We observed a causality between NAFLD and forearm bone mineral density (FABMD) (beta-estimate [β]: - 0.212; p-value: 0.034). We also found that sclerostin can act as a mediator to influence the NAFLD and FABMD pathways to form a mediated MR network (mediated proportion = 8.8%). We also identified indications of causal relationships between other CLDs and OP. However, we were unable to establish any associated mediators. Notably, our analyses did not yield any evidence of pleiotropy. Our findings have implications in the development of preventive and interventional measures aimed at managing low bone mineral density in patients with NAFLD.

Occurrence of bisphosphonate-associated osteonecrosis of the jaws in individuals with rheumatoid arthritis - a systematic review

BACKGROUND

To access the occurrence of bisphosphonate-associated osteonecrosis of the jaw (BAONJ) in individuals with rheumatoid arthritis (RA).

MATERIAL AND METHODS

Observational studies that evaluated the occurrence of BAONJ in individuals with RA (BAONJ-RA) were considered for inclusion. Electronic searches were performed up to December 2022 in six databases and in the grey literature. The study selection, data extraction, and quality assessment of the included studies according to the Joanna Briggs Institute Critical Appraisal Checklists was performed. The certainty of evidence was evaluated using the GRADE approach.

RESULTS

Five studies were included three cohort and two cross-sectional. The sample size of subjects with RA ranged from 16 to 3201. Together, the studies presented 36 cases of BAONJ-RA. Prevalence of BAONJ-RA ranged from 0.094% to 56.25%. The incidence ranged from 0.4% to 2.21. Women between the 6th and 8th decade of life were the most affected. Alendronate (n=5) and zoledronic acid (n=9), orally and intravenously, respectively, were the most used bisphosphonates. The duration of bisphosphonates use ranged from 2.7 to 8 years. The certainty of evidence was very low.

CONCLUSIONS

The occurrence of BAONJ-RA is low. However, the certainty of the evidence was very low for this outcome.

LSD1 inhibition circumvents glucocorticoid-induced muscle wasting of male mice

Synthetic glucocorticoids (GC), such as dexamethasone, are extensively used to treat chronic inflammation and autoimmune disorders. However, long-term treatments are limited by various side effects, including muscle atrophy. GC activities are mediated by the glucocorticoid receptor (GR), that regulates target gene expression in various tissues in association with cell-specific co-regulators. Here we show that GR and the lysine-specific demethylase 1 (LSD1) interact in myofibers of male mice, and that LSD1 connects GR-bound enhancers with NRF1-associated promoters to stimulate target gene expression. In addition, we unravel that LSD1 demethylase activity is required for triggering starvation- and dexamethasone-induced skeletal muscle proteolysis in collaboration with GR. Importantly, inhibition of LSD1 circumvents muscle wasting induced by pharmacological levels of dexamethasone, without affecting their anti-inflammatory activities. Thus, our findings provide mechanistic insights into the muscle-specific GC activities, and highlight the therapeutic potential of targeting GR co-regulators to limit corticotherapy-induced side effects.

Gli1+ Progenitors Mediate Glucocorticoid-Induced Osteoporosis In Vivo

For a wide range of chronic autoimmune and inflammatory diseases in both adults and children, synthetic glucocorticoids (GCs) are one of the most effective treatments. However, besides other adverse effects, GCs inhibit bone mass at multiple levels, and at different ages, especially in puberty. Although extensive studies have investigated the mechanism of GC-induced osteoporosis, their target cell populations still be obscure. Here, our data show that the osteoblast subpopulation among Gli1+ metaphyseal mesenchymal progenitors (MMPs) is responsive to GCs as indicated by lineage tracing and single-cell RNA sequencing experiments. Furthermore, the proliferation and differentiation of Gli1+ MMPs are both decreased, which may be because GCs impair the oxidative phosphorylation(OXPHOS) and aerobic glycolysis of Gli1+ MMPs. Teriparatide, as one of the potential treatments for GCs in bone mass, is sought to increase bone volume by increasing the proliferation and differentiation of Gli1+ MMPs in vivo. Notably, our data demonstrate teriparatide ameliorates GC-caused bone defects by targeting Gli1+ MMPs. Thus, Gli1+ MMPs will be the potential mesenchymal progenitors in response to diverse pharmaceutical administrations in regulating bone formation.

Traditional Chinese medicine in osteoporosis: from pathogenesis to potential activity

Osteoporosis characterized by decreased bone density and mass, is a systemic bone disease with the destruction of microstructure and increase in fragility. Osteoporosis is attributed to multiple causes, including aging, inflammation, diabetes mellitus, and other factors induced by the adverse effects of medications. Without treatment, osteoporosis will further progress and bring great trouble to human life. Due to the various causes, the treatment of osteoporosis is mainly aimed at improving bone metabolism, inhibiting bone resorption, and promoting bone formation. Although the currently approved drugs can reduce the risk of fragility fractures in individuals, a single drug has limitations in terms of safety and effectiveness. By contrast, traditional Chinese medicine (TCM), a characteristic discipline in China, including syndrome differentiation, Chinese medicine prescription, and active ingredients, shows unique advantages in the treatment of osteoporosis and has received attention all over the world. Therefore, this review summarized the pathogenic factors, pathogenesis, therapy limitations, and advantages of TCM, aiming at providing new ideas for the prevention and treatment of OP.

Efficacy of denosumab in the treatment of hypercalcemic renal dysfunction in sarcoidosis: a case report

A 70-year-old female patient was admitted for close examination and treatment of hypercalcemia (corrected serum calcium levels: 3.04 mmol/L) and renal dysfunction (serum creatinine levels: 254.59 µmol/L). The patient had a history of sarcoidosis, diagnosed based on epithelioid cell granulomas in subcutaneous nodule biopsies, uveitis, and bilateral hilar lymphadenopathy, which had spontaneously remitted 10 years before admission. Because the patient was diagnosed with hypercalcemia associated with recurrent sarcoidosis, prednisone (20 mg/day) was initiated, and its dose was tapered following the decrease in serum calcium and creatinine levels. However, the levels of these parameters increased again when the prednisone dose was reduced to ≤ 4 mg/day. We were concerned about glucocorticoid-induced osteoporosis in the patient but hesitated to use first-line bisphosphonates because of renal dysfunction. Therefore, denosumab was initiated to reduce the risk of hypercalcemia, renal dysfunction, and glucocorticoid-induced osteoporosis. Serum creatinine and corrected serum calcium levels subsequently decreased. The prednisone dose could be reduced following repeated denosumab administration.Thus, denosumab can be a multifaceted, beneficial option for sarcoidosis-induced hypercalcemia, as it alleviates renal dysfunction indirectly by normalizing serum calcium levels, facilitates reduction of the glucocorticoid dose, and ameliorates glucocorticoid-induced osteoporosis.

Prognostic nutritional index as an indicator for the development of bone fragility fracture in patients with rheumatoid arthritis

OBJECTIVES

The validity of prognostic nutritional index (PNI) as an index of incident bone fragility fracture (inc-BFF) in rheumatoid arthritis (RA) patients was investigated.

METHODS

RA patients whom continuously followed up for >3 years were picked up. Patients were classified in accordance with inc-BFF positivity (BFF+ and BFF-). Their clinical background including PNI was statistically examined for inc-BFF. The background factors were compared between the two groups. Patients were narrowed into subgroups according to the factor that showed a significant difference between the two groups, and they were statistically examined according to the PNI for the inc-BFF. The two groups were narrowed with propensity score matching and compared to the PNI.

RESULTS

A total of 278 patients with 44 BFF+ and 234 BFF- were recruited. In the background factors, the presence of prevalent BFF and the simplified disease activity index remission rate had a significantly higher risk ratio. In a subgroup who comorbid lifestyle-related diseases, PNI had a significantly higher risk ratio for the inc-BFF. After the propensity score matching, the PNI showed no significant difference between the two groups.

CONCLUSIONS

PNI is available when patients with RA comorbid lifestyle-related diseases. PNI is not an independent key for the inc-BFF in RA patients.

Nationwide prevalence of glucocorticoid prescriptions over 17 years and osteoporosis prevention among long-term users

Objectives

Glucocorticoid steroids are frequently prescribed, and side effects are well-known, such as glucocorticoid-induced osteoporosis. Our aim was to estimate the nationwide trend in the prevalence of glucocorticoid steroid prescriptions over 17 years and to elucidate the proportion of patients on long-term glucocorticoid steroid therapy who receive active bone protective therapy. As well as to examine which medical specialties prescribe glucocorticoid steroids the most.

Methods

This study was a retrospective observational registry study extended over 17 years (2003-2020). Data were retrieved from the Icelandic Prescription Medicine Register on all delivered glucocorticoid steroids (Anatomic therapeutic chemical code: H02AB) for oral use. Long-term users were defined as those who annually received ⩾90 defined daily doses of glucocorticoid steroids.

Results

Annually, 3.8% of the population received oral glucocorticoid steroids, from 3.3% in 2006 to 4.3% in 2017. Prednisolone was most frequently prescribed. Females dispatched glucocorticoid steroid prescriptions more often than males (55.8%). Males and females reached their peak prevalence between the ages of 60 and 70. General practitioners most often prescribe glucocorticoid steroids, followed by physicians in training, rheumatologists, internists, and medical students. Of those who received prescriptions for glucocorticoid steroids, 12.2%-18.1% were classified as long-term users. A declining number of patients have been receiving bone-protective therapy in recent years. Only 13.0% of chronic users received bone protective therapy in 2020.

Conclusion

The use of glucocorticoid steroids has increased during the last 2 decades despite improvements in treatment for inflammatory disorders. The prevalence of long-term users has remained stable. Meanwhile, the use of parallel active bone-protective therapy among long-term users of glucocorticoid steroids is declining. Thus, improvements in prophylaxis for corticosteroid-induced osteoporosis are urgently needed for patients who require long-term treatment with glucocorticoid steroids.

Epidemiology of Osteoporosis in Patients with Chronic Obstructive Pulmonary Disease in Taiwan

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable chronic condition characterized by progressive, partially reversible airflow obstruction. Osteoporosis represents a significant comorbidity in individuals with COPD. However, the incidence and prevalence of osteoporosis among the COPD population remain unclear in Taiwan. Therefore, our objective is to investigate the incidence and prevalence of osteoporosis in patients with COPD.

METHODS

In this cross-sectional study, we enrolled a COPD population retrieved from the Taiwan National Health Insurance Research Database (NHIRD) spanning the years 2003 to 2016. Osteoporosis patients were identified using diagnosis codes. The study included newly diagnosed COPD patients from 2003 to 2016. The case group comprised patients who developed osteoporosis or osteoporotic fractures after their COPD diagnosis. We calculated the prevalence and incidence of osteoporosis in individuals with COPD and conducted trend tests.

RESULTS

A total of 1,297,579 COPD patients were identified during the period from 2003 to 2016, with 275,233 of them in the osteoporosis group. The average prevalence of osteoporosis among individuals with COPD was 21.21% from 2003 to 2016 in Taiwan. The number of osteoporosis cases increased from 6,727 in 2003 to 24,184 in 2016. The prevalence of osteoporosis among COPD patients increased from 3.62% in 2003 to 18.72% in 2016. The number of osteoporosis cases among individuals with COPD continued to rise over the years, reaching its highest point in 2016 with 24,184 new cases. The incidence of osteoporosis fluctuated during the study period but generally remained around 3,000 cases per 100,000 person-years. Notably, there was a significant upward trend in incidence from 2003 to 2006, after which the trend stabilized and remained relatively constant.

CONCLUSIONS

Our study highlights an increase in both the prevalence and incidence of osteoporosis in individuals with COPD. Given the significant medical, economic, and social implications associated with osteoporosis, a comprehensive and robust assessment of its healthcare burden can offer valuable insights for healthcare system planning and policymaking.

Lumbar vertebral bone density is decreased in horses with pituitary pars intermedia dysfunction

BACKGROUND

Pathological fractures have been reported in equids with pituitary pars intermedia dysfunction (PPID) but their prevalence and pathogenesis is unknown.

OBJECTIVES

To compare: (1) bone mineral density (BMD) in weight bearing and nonweight bearing bones in PPID+ equids and aged and young PPID- controls; and (2) biomechanical properties of the fourth lumbar vertebral body in PPID+ equids and aged PPID- equids.

STUDY DESIGN

Case-control study: five PPID+ equids and six aged and four young PPID- control horses.

METHODS

PPID status was based on clinical signs and necropsy examination of the pituitary gland (PG). The lumbar vertebral column, right front third metacarpus (MC3), left hind third metatarsus (MT3), and PG were removed after euthanasia. BMD was determined by quantitative computed tomography of regions of interest (ROI) in each bone and biomechanical testing was performed on the fourth lumbar vertebral body. Serum concentrations of parathormone (PTH), ionised Ca++ , 25-hydroxyvitamin D, and osteocalcin (OC) were also measured. Data were analysed using one-way ANOVA and correlation analyses.

RESULTS

BMD of trabecular and cortical regions of interest (ROI) of the third, fourth (L4), and fifth lumbar vertebrae were significantly lower in PPID+ equids as compared with aged (p < 0. 001) and young (p < 0.01) PPID- controls. In contrast, no differences were found in BMD of trabecular or cortical ROIs of MC3 and MT3 between groups. No differences were detected in force at fracture, displacement at fracture, Young's modulus or strain of L4 between PPID+ and aged PPID- horses. No differences were found in serum PTH, ionised Ca++ , 25-hydroxyvitamin D, or OC concentrations between groups.

MAIN LIMITATIONS

Limited number of equids studied and variation in test results.

CONCLUSIONS

BMD of nonweight bearing bones can be decreased with PPID and could increase risk of developing pathological fractures.

Extrapulmonary Comorbidities Associated with Chronic Obstructive Pulmonary Disease: A Review

Most patients with chronic obstructive pulmonary disease (COPD) suffer from at least one additional, clinically relevant chronic disease. To a degree, the high global prevalence and mortality rate of COPD is closely related to its extrapulmonary effects. Moreover, the various of comorbidities of COPD and itself interact with each other, resulting in diverse clinical manifestations and individual differences, and thus further influencing the prognosis as well as healthcare burden of COPD patients. This is closely related to the common risk factors of chronic diseases (aging, smoking, inactivity, etc.). Additionally, some pathophysiological mechanisms caused by COPD, including the systemic inflammatory response, hypoxia, oxidative stress, and others, also have an impact on other systems. But comprehensive management and medical interventions have not yet been established. The clinicians should improve their knowledge and skills in diagnosing as well as treating the comorbidities of COPD, and then aim to develop more individualized, efficient diagnostic and therapeutic strategies for different patients to achieve greater clinical benefits. In this article, we will review the risk factors, mechanisms, and treatment strategies for extrapulmonary comorbidities in chronic obstructive pulmonary disease, including cardiovascular diseases, diabetes, anemia, osteoporosis, emotional disorders, and gastroesophageal reflux disease.

Insights and implications of sexual dimorphism in osteoporosis

Osteoporosis, a metabolic bone disease characterized by low bone mineral density and deterioration of bone microarchitecture, has led to a high risk of fatal osteoporotic fractures worldwide. Accumulating evidence has revealed that sexual dimorphism is a notable feature of osteoporosis, with sex-specific differences in epidemiology and pathogenesis. Specifically, females are more susceptible than males to osteoporosis, while males are more prone to disability or death from the disease. To date, sex chromosome abnormalities and steroid hormones have been proven to contribute greatly to sexual dimorphism in osteoporosis by regulating the functions of bone cells. Understanding the sex-specific differences in osteoporosis and its related complications is essential for improving treatment strategies tailored to women and men. This literature review focuses on the mechanisms underlying sexual dimorphism in osteoporosis, mainly in a population of aging patients, chronic glucocorticoid administration, and diabetes. Moreover, we highlight the implications of sexual dimorphism for developing therapeutics and preventive strategies and screening approaches tailored to women and men. Additionally, the challenges in translating bench research to bedside treatments and future directions to overcome these obstacles will be discussed.

SARS-CoV-2 and its Multifaceted Impact on Bone Health: Mechanisms and Clinical Evidence

PURPOSE OF REVIEW

SARS-CoV-2 infection, the culprit of the COVID-19 pandemic, has been associated with significant long-term effects on various organ systems, including bone health. This review explores the current understanding of the impacts of SARS-CoV-2 infection on bone health and its potential long-term consequences.

RECENT FINDINGS

As part of the post-acute sequelae of SARS-CoV-2 infection, bone health changes are affected by COVID-19 both directly and indirectly, with multiple potential mechanisms and risk factors involved. In vitro and preclinical studies suggest that SARS-CoV-2 may directly infect bone marrow cells, leading to alterations in bone structure and osteoclast numbers. The virus can also trigger a robust inflammatory response, often referred to as a "cytokine storm", which can stimulate osteoclast activity and contribute to bone loss. Clinical evidence suggests that SARS-CoV-2 may lead to hypocalcemia, altered bone turnover markers, and a high prevalence of vertebral fractures. Furthermore, disease severity has been correlated with a decrease in bone mineral density. Indirect effects of SARS-CoV-2 on bone health, mediated through muscle weakness, mechanical unloading, nutritional deficiencies, and corticosteroid use, also contribute to the long-term consequences. The interplay of concurrent conditions such as diabetes, obesity, and kidney dysfunction with SARS-CoV-2 infection further complicates the disease's impact on bone health. SARS-CoV-2 infection directly and indirectly affects bone health, leading to potential long-term consequences. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.