RANKL inhibition improves muscle strength and insulin sensitivity and restores bone mass

Assessment of lower limb muscle strength can predict fall risk in patients with chronic liver disease

Falls are caused by a combination of factors, including loss of lower limb muscle strength (LMS), and associated with declined performance status (PS). Age-related sarcopenia is generally associated with decreased muscle mass and strength of lower limb muscle but without a noticeable loss of those of upper limb or trunk muscle. However, no reports have focused on falls or LMS in chronic liver disease (CLD) patients. This study is the first to analyze the risk factors for falls in patients with CLD, focusing on LMS measurement using the Locomoscan. This study enrolled 315 CLD patients whose LMS was measured. The patients who experienced falls more than 1 year ago or during the observation period were classified as those who experienced falls. We found that risk factors for falls were PS1/2 and decreased LMS (< 0.32 N/kg). The group with sarcopenia had a higher frequency of decreased LMS (54 vs. 26%, p = 0.001) and falls (24 vs. 4.4%, p < 0.001) compared to the non-sarcopenia group. This study found that decreased LMS was an independent risk factor for falls. Assessment of LMS may be used as a better marker associated with the risk of falls in patients with CLD.

Effect of denosumab on glucose metabolism in postmenopausal osteoporotic women with prediabetes: a study protocol for a 12-month multicenter, open-label, randomized controlled trial

BACKGROUND

Participants with prediabetes are at a high risk of developing type 2 diabetes (T2D). Recent studies have suggested that blocking the receptor activator of nuclear factor-κB ligand (RANKL) may improve glucose metabolism and delay the development of T2D. However, the effect of denosumab, a fully human monoclonal antibody that inhibits RANKL, on glycemic parameters in the prediabetes population is uncertain. We aim to examine the effect of denosumab on glucose metabolism in postmenopausal women with osteoporosis and prediabetes.

METHODS

This is a 12-month multicenter, open-label, randomized controlled trial involving postmenopausal women who have been diagnosed with both osteoporosis and prediabetes. Osteoporosis is defined by the World Health Organization (WHO) as a bone mineral density T score of ≤ - 2.5, as measured by dual-energy X-ray absorptiometry (DXA). Prediabetes is defined as (i) a fasting plasma glucose level of 100-125 mg/dL, (ii) a 2-hour plasma glucose level of 140-199 mg/dL, or (iii) a glycosylated hemoglobin A1c (HbA1c) level of 5.7-6.4%. A total of 346 eligible subjects will be randomly assigned in a 1:1 ratio to receive either subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg every week for 12 months. The primary outcome is the change in HbA1c levels from baseline to 12 months. Secondary outcomes include changes in fasting and 2-hour blood glucose levels, serum insulin levels, C-peptide levels, and insulin sensitivity from baseline to 12 months, and the incidence of T2D at the end of the study. Follow-up visits will be scheduled at 3, 6, 9, and 12 months.

DISCUSSION

This study aims to provide evidence on the efficacy of denosumab on glucose metabolism in postmenopausal women with osteoporosis and prediabetes. The results derived from this clinical trial may provide insight into the potential of denosumab in preventing T2D in high-risk populations.

TRIAL REGISTRATION

This study had been registered in the Chinese Clinical Trials Registry.

REGISTRATION NUMBER

ChiCTR2300070789 on April 23, 2023. https://www.chictr.org.cn .

A non-invasive mouse model that recapitulates disuse-induced muscle atrophy in immobilized patients

Disuse muscle atrophy occurs consequent to prolonged limb immobility or bed rest, which represents an unmet medical need. As existing animal models of limb immobilization often cause skin erosion, edema, and other untoward effects, we here report an alternative method via thermoplastic immobilization of hindlimbs in mice. While significant decreases in the weight and fiber size were noted after 7 days of immobilization, no apparent skin erosion or edema was found. To shed light onto the molecular mechanism underlying this muscle wasting, we performed the next-generation sequencing analysis of gastrocnemius muscles from immobilized versus non-mobilized legs. Among a total of 55,487 genes analyzed, 787 genes were differentially expressed (> fourfold; 454 and 333 genes up- and down-regulated, respectively), which included genes associated with muscle tissue development, muscle system process, protein digestion and absorption, and inflammation-related signaling. From a clinical perspective, this model may help understand the molecular/cellular mechanism that drives muscle disuse and identify therapeutic strategies for this debilitating disease.

Bone turnover biomarkers predict one-year all-cause mortality and walking ability in geriatric hip fracture patients

PURPOSE

To investigate the utility of serum C-terminal cross-linking telopeptides (β-CTX) and procollagen type I N propeptide (PINP) for predicting one-year mortality and walking ability in Chinese geriatric hip fracture patients who underwent surgical interventions.

METHOD

Elderly patients (≥ 60 years) who underwent surgical interventions for unilateral low-energy hip fracture from 2015 to 2020 in our center were included. Demographic data was retrospectively retrieved from the electronic medical database. The PINP and β-CTX concentrations were measured before the surgery. The patients were divided into two groups according to the outcome of mortality and walking ability after hip surgery, respectively. β-CTX and PINP were divided into four grades based on quartiles [Quartile(Q)1-4] for further analysis. All the variables with p < 0.1 in univariable analysis were included in a multivariable model.

RESULTS

In univariable analysis, the levels of serum β-CTX (p = 0.007) and PINP (p = 0.025) was associated with one-year mortality, while the association between levels of serum β-CTX (p = 0.072) or PINP (p = 0.055) with one-year disability was marginally significant. After adjustment for confounders, the relative risk [OR (95 % CI), Q4 v sQ1, p-value] of one-year mortality and one-year disability were 7.28 (2.08-29.78, p = 0.003) and 3.97 (1.44-11.69, p = 0.009) for β-CTX and 5.87 (1.70-23.80, p = 0.008) and 3.48 (1.30-9.93, p = 0.016) for PINP, respectively. The coefficient of determination, AUC and bias-corrected C-index of predictive models based on previously reported predictors were significantly improved after integrating β-CTX or PINP.

CONCLUSION

Higher serum β-CTX and PINP are independently associated with an increased risk of one-year mortality and disability in patients with hip fractures. The application of BTMs improves the performance of currently available predictive models.

Potential application of anti-osteoporotic therapy to relieve sarcopenia in the elderly

Sarcopenia is a progressive and systemic skeletal muscle disorder associated with aging that usually occurs with age in the elderly. Sarcopenia currently lacks effective pharmacological treatment modalities. Multiple pharmacological intervention modalities are available for osteoporosis, a comprehensive disease characterized by decreased systemic bone mass, degradation of bone microarchitecture, and increased bone fragility. Several recent studies have shown an extremely strong correlation between sarcopenia and osteoporosis, leading to the concept of "osteosarcopenia". Therefore, it is possible to alleviate sarcopenia simultaneously by improving osteoporosis.

Titanium particles in peri-implantitis: distribution, pathogenesis and prospects

Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.

Sex Differences in Bone, Muscle, and Inflammatory Markers and Their Associations with Muscle Performance Variables

The importance of various markers such as Sclerostin, Dickkopf-1 (DKK-1), Irisin, receptor activator of NF-kB ligand (RANKL), and Vitamin D have been well studied in bone metabolism. Additionally, inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and Interleukin 6 (IL-6) have been shown to hinder muscle protein synthesis, leading to the loss of muscle and strength. However, a research gap exists in understanding their role in muscle function and physical activity. Therefore, this study aims to explore the serum levels of Sclerostin, DKK-1, Irisin, IL-6, RANKL, Vitamin D, and TNF-α and assess their relationships with upper- and lower-body strength in young adults. In this study, 38 college-aged students (18-23 years), males and females, participated and completed the protocols. The participants' lower and upper body strength were assessed by the vertical jump test (Just Jump, Probotic, AL) with a Tendo FitroDyne (Tendo Sports Machines, Trencin, Slovak Republic) and handgrip (HG) dynamometry (Takei Scientific Instruments, Yashiroda, Japan), respectively. Fasting morning blood samples were analyzed for serum levels of biomarkers by ELISA. The results indicate significant sex differences in Sclerostin, DKK-1, Irisin, and Vitamin D levels (p < 0.05). Furthermore, a positive association was observed between Sclerostin, DKK-1, and Vitamin D, with lower body muscle performance variables (p < 0.05). Conversely, a significant negative correlation was observed between TNF-α and lower-body muscle performance variables (p < 0.05). The results suggest that these markers may have a distinct effect on muscle performance, underscoring the need for further investigation to elucidate the concept of muscle-bone crosstalk.

RANKL/RANK is required for cytokine-induced beta cell death; osteoprotegerin, a RANKL inhibitor, reverses rodent type 1 diabetes

Treatment for type 1 diabetes (T1D) requires stimulation of functional β cell regeneration and survival under stress. Previously, we showed that inhibition of the RANKL/RANK [receptor activator of nuclear factor kappa Β (NF-κB) ligand] pathway, by osteoprotegerin and the anti-osteoporotic drug denosumab, induces rodent and human β cell proliferation. We demonstrate that the RANK pathway mediates cytokine-induced rodent and human β cell death through RANK-TRAF6 interaction and induction of NF-κB activation. Osteoprotegerin and denosumab protected β cells against this cytotoxicity. In human immune cells, osteoprotegerin and denosumab reduce proinflammatory cytokines in activated T-cells by inhibiting RANKL-induced activation of monocytes. In vivo, osteoprotegerin reversed recent-onset T1D in nonobese diabetic/Ltj mice, reduced insulitis, improved glucose homeostasis, and increased plasma insulin, β cell proliferation, and mass in these mice. Serum from T1D subjects induced human β cell death and dysfunction, but not α cell death. Osteoprotegerin and denosumab reduced T1D serum-induced β cell cytotoxicity and dysfunction. Inhibiting RANKL/RANK could have therapeutic potential.

Anti-RANKL Therapy Prevents Glucocorticoid-Induced Bone Loss and Promotes Muscle Function in a Mouse Model of Duchenne Muscular Dystrophy

Bisphosphonates prevent bone loss in glucocorticoid (GC)-treated boys with Duchenne muscular dystrophy (DMD) and are recommended as standard of care. Targeting receptor activator of nuclear factor kappa-B ligand (RANKL) may have advantages in DMD by ameliorating dystrophic skeletal muscle function in addition to their bone anti-resorptive properties. However, the potential effects of anti-RANKL treatment upon discontinuation in GC-induced animal models of DMD are unknown and need further investigation prior to exploration in the clinical research setting. In the first study, the effects of anti-RANKL and deflazacort (DFZ) on dystrophic skeletal muscle function and bone microstructure were assessed in mdx mice treated with DFZ or anti-RANKL, or both for 8 weeks. Anti-RANKL and DFZ improved grip force performance of mdx mice but an additive effect was not noted. However, anti-RANKL but not DFZ improved ex vivo contractile properties of dystrophic muscles. This functional improvement was associated with a reduction in muscle damage and fibrosis, and inflammatory cell number. Anti-RANKL treatment, with or without DFZ, also improved trabecular bone structure of mdx mice. In a second study, intravenous zoledronate (Zol) administration (1 or 2 doses) following 2 months of discontinuation of anti-RANKL treatment was mostly required to record an improvement in bone microarchitecture and biomechanical properties in DFZ-treated mdx mice. In conclusion, the ability of anti-RANKL therapy to restore muscle function has profound implications for DMD patients as it offers the possibility of improving skeletal muscle function without the steroid-related skeletal side effects.

OPG gene-modified adipose-derived stem cells improve bone formation around implants in osteoporotic rat maxillae

Background

Osteoporosis is a significant barrier to the use of dental implants in the elderly for the treatment of tooth defects. Adipose derived stem cells (ADSCs) have demonstrated extensive potential for tissue repair and regeneration. The present study aimed to investigate the effectiveness of ADSCs engineered to express high levels of osteoprotegerin (OPG) for the treatment of bone loss in implant dentistry caused by estrogen deficiency.

Methods

A rat model of osteoporosis was established through double oophorectomy, and the rats were treated by gene modified cells Adv-OPG-ADSCs. The effects of the treatment on maxilla tissue changes were evaluated using HE staining and micro-CT. Additionally, ALP and TRAP staining were used to assess osteoblast and osteoclast alterations. Finally, the changes in related osteoblast and osteoclast indicators were measured by RT-qPCR, Western blot, and ELISA.

Results

The successfully generated high-OPG-expressing ADSCs led to increase of cell viability, proliferation, and osteoblast differentiation. Treatment with Adv-OPG-ADSCs significantly ameliorated maxillary morphology, trabecular volume reduction, and bone mineral density decline in the model of estrogen-deficient maxillary implant dentistry. Furthermore, the treatment was beneficial to promoting the generation of osteoblasts and inhibiting the generation of osteoclast. Adv-OPG-ADSCs increased OPG, ALP, OCN, and Runx-2 expressions in the maxilla while suppressing RANKL expression, and also increased the concentration of COL I and PINP, as well as decreased the concentration of CTX-1.

Conclusion

Adv-OPG-ADSCs promote the formation of osteoblasts and inhibit the generation of osteoclasts, thereby inhibiting bone absorption, facilitating bone formation, and promoting the repair of maxillary bone after dental implantation in the presence of osteoporosis-related complications, especially in the setting of estrogen deficiency, providing scientific basis for the application of Adv-OPG-ADSCs in the treatment of implant related osteoporosis.

Evidence in Humans for Bone as an Endocrine Organ Regulating Energy Metabolism

There is increasing evidence from animal models that bone, in addition to its traditional function of providing structural support for the organism, has a rich network of interactions with multiple other tissues. This perspective focuses on evidence from human studies demonstrating that bone is an endocrine organ regulating energy metabolism, with the specific examples being osteocalcin, lipocalin 2, RANKL, and sclerostin. Conversely, animal studies have also demonstrated that a key hormone regulating energy metabolism, leptin, regulates bone metabolism via the sympathetic nervous system. Studies in humans have established a role for the sympathetic nervous system in regulating bone turnover; indeed, the potential therapeutic benefit of targeting this pathway in humans to prevent postmenopausal bone loss is currently being evaluated.

Pro-Inflammatory Proteins Associated with Frailty and Its Progression-A Longitudinal Study in Community-Dwelling Women

The complex pathophysiology underlying biological aging creates challenges for identifying biomarkers associated with frailty. This longitudinal, nontargeted proteomics study aimed to identify proteins associated with frailty, particularly the change from nonfrail to frail. The population-based Osteoporosis Prospective Risk Assessment cohort includes women all of whom are 75 years old at inclusion (n = 1044) and reassessed at 80 years (n = 715) and 85 years (n = 382). A deficits in health frailty index (FI) and 92 plasma proteins (Olink CVD-II panel) were available at all ages. The identical age facilitated differentiating chronological and biological aging. Bidirectional analyses, performed cross-sectionally and longitudinally, used regression models controlled for false discovery rate (FDR), across 5- and 10-year time windows and longitudinal mixed models. Frailty outcomes were frailty index, frailty status (frail defined as FI ≥ 0.25), change in frailty index, and change in frailty status, together with protein expression or change in protein expression. Elevated levels of 32 proteins were positively associated with the FI, cross-sectionally at all ages (range: β-coefficients 0.22-2.06; FDR 0.021-0.024), of which 18 were also associated with frailty status (range: odds ratios 1.40-5.77; FDR 0.022-0.016). Based on the accrued data, eight core proteins (CD4, FGF23, Gal-9, PAR-1, REN, TNFRSF10A TNFRSF11A, and TNFRSF10B) are proposed. A one-unit change in the FI was additively associated with increased protein expression over 5 and 10 years (range: β-coefficients 0.52-1.59; p < 0.001). Increments in baseline FI consistently associated with a change in protein expression over time (5 years, β-range 0.05-1.35; 10 years, β-range 0.51-1.48; all p < 0.001). A one-unit increase in protein expression was also associated with an increased probability of being frail (FI ≥ 0.25) (β-range: 0.14-0.61). Mirroring the multisystem deterioration that typifies frailty, the proteins and their associated biological pathways reflect pathologies, including the renal system, skeletal homeostasis, and TRAIL-activated apoptotic signaling. The core proteins are compelling candidates for understanding the development and progression of frailty with advancing age, including the intrinsic musculoskeletal component. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Sarcopenia in Men With Bone-Predominant Metastatic Castration-Resistant Prostate Cancer Undergoing Ra-223 Therapy

INTRODUCTION

Osteosarcopenia is the progressive loss of musculoskeletal structure and functionality, contributing to disability and mortality. Despite complex interactions between bone and muscle, osteosarcopenia prevention and treatment in men with metastatic castration-resistant prostate cancer (mCRPC) focuses predominantly on bone health. It is unknown whether Radium-223 (Ra-223) therapy affects sarcopenia.

METHODS

We identified 52 patients with mCRPC who had received Ra-223 and had a baseline plus ≥1 follow-up abdominopelvic CT scan. The total contour area (TCA) and averaged Hounsfield units (HU) of the left and right psoas muscles were obtained at the inferior L3 endplate, and the psoas muscle index (PMI) was calculated therefrom. Intrapatient musculoskeletal changes were analyzed across various time points.

RESULTS

TCA and PMI gradually declined over the study period (P = .002, P = .003, respectively), but Ra-223 therapy did not accelerate sarcopenia, nor the decline of HU compared to the pre-Ra-223 period. The median overall survival of patients with baseline sarcopenia was numerically worse (14.93 vs. 23.23 months, HR 0.612, P = .198).

CONCLUSIONS

Ra-223 does not accelerate sarcopenia. Thus, worsening muscle parameters in men with mCRPC undergoing Ra-223 therapy are attributable to other factors. Further research is needed to determine whether baseline sarcopenia predicts poor overall survival in such patients.

Negative association between triglyceride glucose index and BMI-adjusted skeletal muscle mass index in hypertensive adults

BACKGROUND

The triglyceride glucose (TyG) index, an indicator of insulin resistance, is often associated with adverse outcomes in various cardiovascular diseases, while hypertension is associated with an increased risk of cardiovascular diseases. As the loss of muscle mass in people with hypertension is poorly understood, the current study aimed to explore the relationship between TyG index and muscle mass in hypertensive population.

METHODS

We analyzed data from hypertensive adult participants in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. The TyG index and body mass index (BMI)-adjusted skeletal muscle mass index (SMI) were calculated and the relationship between the two was evaluated using multivariable linear regression and restricted cubic spline (RCS) regression models.

RESULTS

A total of 1633 participants in the dataset were included for the final analysis. In the multivariable regression analysis, the adjusted β of SMI with a 95% confidence interval (CI) for the highest TyG index quartile was - 5.27 (- 9.79 to - 0.75), compared with the lowest quartile. A negative linear relationship between TyG index and SMI was plotted by RCS regression (nonlinear P = 0.128). Stratified models of non-smoking women of different ages also demonstrated that SMI decreased as TyG index increased (all P for trend < 0.05).

CONCLUSION

This linear and negative correlation between TyG index and SMI in hypertensive patients suggests that insulin resistance adversely affects muscle mass.

Pathophysiological mechanism of acute bone loss after fracture

BACKGROUND

Acute bone loss after fracture is associated with various effects on the complete recovery process and a risk of secondary fractures among patients. Studies have reported similarities in pathophysiological mechanisms involved in acute bone loss after fractures and osteoporosis. However, given the silence nature of bone loss and bone metabolism complexities, the actual underlying pathophysiological mechanisms have yet to be fully elucidated.

AIM OF REVIEW

To elaborate the latest findings in basic research with a focus on acute bone loss after fracture. To briefly highlight potential therapeutic targets and current representative drugs. To arouse researchers' attention and discussion on acute bone loss after fracture.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Bone loss after fracture is associated with immobilization, mechanical unloading, blood supply damage, sympathetic nerve regulation, and crosstalk between musculoskeletals among other factors. Current treatment strategies rely on regulation of osteoblasts and osteoclasts, therefore, there is a need to elucidate on the underlying mechanisms of acute bone loss after fractures to inform the development of efficacious and safe drugs. In addition, attention should be paid towards ensuring long-term skeletal health.

Messages from the Mineral: How Bone Cells Communicate with Other Tissues

Bone is a highly dynamic tissue, and the constant actions of bone-forming and bone-resorbing cells are responsible for attaining peak bone mass, maintaining bone mass in the adults, and the subsequent bone loss with aging and menopause, as well as skeletal complications of diseases and drug side-effects. It is now accepted that the generation and activity of bone-forming osteoblasts and bone-resorbing osteoclasts is modulated by osteocytes, osteoblast-derived cells embedded in the bone matrix. The interaction among bone cells occurs through direct contact and via secreted molecules. In addition to the regulation of bone cell function, molecules released by these cells are also able to reach the circulation and have effects in other tissues and organs in healthy individuals. Moreover, bone cell products have also been associated with the establishment or progression of diseases, including cancer and muscle weakness. In this review, we will discuss the role of bone as an endocrine organ, and the effect of selected, osteoblast-, osteocyte-, and osteoclast-secreted molecules on other tissues.

Sarcopenia, osteoporosis and frailty

Muscles and bones are intricately connected tissues displaying marked co-variation during development, growth, aging, and in many diseases. While the diagnosis and treatment of osteoporosis are well established in clinical practice, sarcopenia has only been classified internationally as a disease in 2016. Both conditions are associated with an increased risk of adverse health outcomes such as fractures, dysmobility and mortality. Rather than focusing on one dimension of bone or muscle mass or weakness, the concept of musculoskeletal frailty captures the overall loss of physiological reserves in the locomotor system with age. The term osteosarcopenia in particular refers to the double jeopardy of osteoporosis and sarcopenia. Muscle-bone interactions at the biomechanical, cellular, paracrine, endocrine, neuronal or nutritional level may contribute to the pathophysiology of osteosarcopenia. The paradigm wherein muscle force controls bone strength is increasingly facing competition from a model centering on the exchange of myokines, osteokines and adipokines. The most promising results have been obtained in preclinical models where common drug targets have been identified to treat these conditions simultaneously. In this narrative review, we critically summarize the current understanding of the definitions, epidemiology, pathophysiology, and treatment of osteosarcopenia as part of an integrative approach to musculoskeletal frailty.

Denosumab Attenuates Glucolipotoxicity-Induced β-Cell Dysfunction and Apoptosis by Attenuating RANK/RANKL Signals

Obesity is strongly associated with insulin sensitivity in type 2 diabetes (T2D), mainly because free fatty acids (FFAs) are released from excess fat tissue. Long-term exposure to high levels of FFAs and glucose leads to glucolipotoxicity, causing damage to pancreatic β-cells, thus accelerating the progression of T2D. Therefore, the prevention of β-cell dysfunction and apoptosis is essential to prevent the development of T2D. Unfortunately, there are currently no specific clinical strategies for protecting β-cells, highlighting the need for effective therapies or preventive approaches to improve the survival of β-cells in T2D. Interestingly, recent studies have shown that the monoclonal antibody denosumab (DMB), used in osteoporosis, displays a positive effect on blood glucose regulation in patients with T2D. DMB acts as an osteoprotegerin (OPG) by inhibiting the receptor activator of the NF-κB ligand (RANKL), preventing the maturation and function of osteoclasts. However, the exact mechanism by which the RANK/RANKL signal affects glucose homeostasis has not been fully explained. The present study used human 1.4 × 10⁷ β-cells to simulate the T2D metabolic condition of high glucose and free fatty acids (FFAs), and it investigated the ability of DMB to protect β-cells from glucolipotoxicity. Our results show that DMB effectively attenuated the cell dysfunction and apoptosis caused by high glucose and FFAs in β-cells. This may be caused by blocking the RANK/RANKL pathway that reduced mammalian sterile 20-like kinase 1 (MST1) activation and indirectly increased pancreatic and duodenal homeobox 1 (PDX-1) expression. Furthermore, the increase in inflammatory cytokines and ROS caused by the RANK/RANKL signal also played an important role in glucolipotoxicity-induced cytotoxicity, and DMB can also protect β-cells by reducing the mechanisms mentioned above. These findings provide detailed molecular mechanisms for the future development of DMB as a potential protective agent of β-cells.

Bone turnover profile and muscular status in major orthopaedic surgery: a case series

BACKGROUND Sarcopenia refers to a chronic loss of skeletal muscle mass, often associated with hypovitaminosis D and advanced age, which involves a greater risk of falls and fractures. The association of sarcopenia and osteoporosis defines osteo-sarcopenia. In this work, the authors analyzed the osteometabolic profile and the loco-regional muscular state of patients undergoing major orthopedic surgery, in order to define the incidence of district osteosarcopenic states, linked to a condition of disuse.   METHODS   19 patients (10M-9F), between 15 and 85 years old, underwent major orthopedic surgery (15 resection prosthesis and custom made, 2 resection and reconstruction with transplant) were evaluated, of which 9 on an oncological basis. In all patients, the phospho-calcium metabolism was assessed by blood tests and intraoperative muscle biopsy was performed at the intervention site and contralaterally; in 3 cases a densitometric comparative study of the affected/contralateral limb was performed.   RESULTS   Results shows 5 patients with hypovitaminosis D; 7 pcs with hypocalcemia; 5 with PTH rise; 4pcs with ALP increase. In 100% of cases, the biopsy revealed sarcopenic patterns exclusively on the affected limb. 2 out of 3 DEXAs (66%) showed loco-regional osteoporosis compared to the contralateral.   CONCLUSIONS   The fact that in our sample sarcopenia is unilateral affecting only the pathological limb, that it is frequently associated with osteoporosis which is also unilateral and that for the most part it is not associated with vitamin D deficiency, suggests that it is an independent condition, with etiopathogenetic mechanisms different from osteosarcopenia itself. In major orthopedic surgery, bone integration and muscle status are both essential for achieving and lasting positive results. Considering the high incidence of district osteosarcopenia, an integrated surgical, pharmacological, and rehabilitative approach is desirable for the optimization of results, as well as more studies for the definition of the etiopathogenesis of this pathological condition.

RANKL Inhibition Reduces Cardiac Hypertrophy in mdx Mice and Possibly in Children with Duchenne Muscular Dystrophy

Cardiomyopathy has become one of the leading causes of death in patients with Duchenne muscular dystrophy (DMD). We recently reported that the inhibition of the interaction between the receptor activator of nuclear factor κB ligand (RANKL) and receptor activator of nuclear factor κB (RANK) significantly improves muscle and bone functions in dystrophin-deficient mdx mice. RANKL and RANK are also expressed in cardiac muscle. Here, we investigate whether anti-RANKL treatment prevents cardiac hypertrophy and dysfunction in dystrophic mdx mice. Anti-RANKL treatment significantly reduced LV hypertrophy and heart mass, and maintained cardiac function in mdx mice. Anti-RANKL treatment also inhibited NFκB and PI3K, two mediators implicated in cardiac hypertrophy. Furthermore, anti-RANKL treatment increased SERCA activity and the expression of RyR, FKBP12, and SERCA2a, leading possibly to an improved Ca2+ homeostasis in dystrophic hearts. Interestingly, preliminary post hoc analyses suggest that denosumab, a human anti-RANKL, reduced left ventricular hypertrophy in two patients with DMD. Taken together, our results indicate that anti-RANKL treatment prevents the worsening of cardiac hypertrophy in mdx mice and could potentially maintain cardiac function in teenage or adult patients with DMD.

Quality of life of postmenopausal women with teriparatide, denosumab and alendronate: One-year prospective study with a propensity score-matched comparison

Background/purpose: To evaluate and compare the effects of parathyroid hormone analogues, receptor activators of nuclear factor kappa-B ligand inhibitors and bisphosphonates on the quality of life of postmenopausal women. Methods: A prospective observational study of 23 matched postmenopausal women was conducted with propensity score analysis on quality of life at one-year follow-up. Visual analogue scale for back pain and outcome scores were carried out as the quality of life or treatment adherence measurements. Results: Teriparatide use was associated with significant improvements in visual analogue scale, EuroQol 5-level 5-dimension general health status and Osteoporosis Assessment Questionnaire physical function, whereas denosumab and alendronate groups only demonstrated improved Osteoporosis Assessment Questionnaire scores but worsened back pain. Baseline average visual analogue scale back pain predicted one-year average back pain progression (partial eta squared = 0.617, p = 0.001). Conclusions: One-year continuous teriparatide treatment is most effective in improving quality of life outcomes in postmenopausal osteoporotic women. Baseline average visual analogue scale back pain remained the only predictive factor for one-year back pain progression.

RANKL inhibition: a new target of treating diabetes mellitus?

Accumulating evidence demonstrates the link between glucose and bone metabolism. The receptor activator of nuclear factor-kB ligand (RANKL)/the receptor activator of NF-κB (RANK)/osteoprotegerin (OPG) axis is an essential signaling axis maintaining the balance between bone resorption and bone formation. In recent years, it has been found that RANKL and RANK are distributed not only in bone but also in the liver, muscle, adipose tissue, pancreas, and other tissues that may influence glucose metabolism. Some scholars have suggested that the blockage of the RANKL signaling may protect islet β-cell function and prevent diabetes; simultaneously, there also exist different views that RANKL can improve insulin resistance through inducing the beige adipocyte differentiation and increase energy expenditure. Currently, the results of the regulatory effect on glucose metabolism of RANKL remain conflicting. Denosumab (Dmab), a fully human monoclonal antibody that can bind to RANKL and prevent osteoclast formation, is a commonly used antiosteoporosis drug. Recent basic studies have found that Dmab seems to regulate glucose homeostasis and β-cell function in humanized mice or in vitro human β-cell models. Besides, some clinical data have also reported the glucometabolic effects of Dmab, however, with limited and inconsistent results. This review mainly describes the impact of the RANKL signaling pathway on glucose metabolism and summarizes clinical evidence that links Dmab and DM to seek a new therapeutic strategy for diabetes.

Osteoprotegerin/Receptor Activator of Nuclear Factor-Kappa B Ligand/Receptor Activator of Nuclear Factor-Kappa B Axis in Obesity, Type 2 Diabetes Mellitus, and Nonalcoholic Fatty Liver Disease

PURPOSE OF REVIEW

To summarize evidence on the potential involvement of the osteoprotegerin (OPG)/receptor activator of nuclear factor-kappa B (NF-κΒ) ligand (RANKL)/receptor activator of NF-κΒ (RANK) axis in the pathogenesis of metabolic diseases.

RECENT FINDINGS

The OPG-RANKL-RANK axis, which has been originally involved in bone remodeling and osteoporosis, is now recognized as a potential contributor in the pathogenesis of obesity and its associated comorbidities, i.e., type 2 diabetes mellitus and nonalcoholic fatty liver disease. Besides bone, OPG and RANKL are also produced in adipose tissue and may be involved in the inflammatory process associated with obesity. Metabolically healthy obesity has been associated with lower circulating OPG concentrations, possibly representing a counteracting mechanism, while elevated serum OPG levels may reflect an increased risk of metabolic dysfunction or cardiovascular disease. OPG and RANKL have been also proposed as potential regulators of glucose metabolism and are potentially involved in the pathogenesis of type 2 diabetes mellitus. In clinical terms, type 2 diabetes mellitus has been consistently associated with increased serum OPG concentrations. With regard to nonalcoholic fatty liver disease, experimental data suggest a potential contribution of OPG and RANKL in hepatic steatosis, inflammation, and fibrosis; however, most clinical studies showed reduction in serum concentrations of OPG and RANKL. The emerging contribution of the OPG-RANKL-RANK axis to the pathogenesis of obesity and its associated comorbidities warrants further investigation by mechanistic studies and may have potential diagnostic and therapeutic implications.

Osteosarcopenia and Pain: Do We Have a Way Out?

Osteosarcopenia (OSP) is a geriatric syndrome characterized by the coexistence of osteoporosis and sarcopenia and associated with an increased risk of fragility fractures, disability, and mortality. For patients with this syndrome, musculoskeletal pain represents the most significant challenge since, in addition to limiting the individual's functionality and promoting disability, it has a huge psychological burden involving anxiety, depression, and social withdrawal. Unfortunately, the molecular mechanisms involved in the development and persistence of pain in OSP have not yet been fully elucidated, although immune cells are known to play a key role in these processes. Indeed, they release several molecules that promote persistent inflammation and nociceptive stimulation, resulting in the gating of ion channels responsible for the generation and propagation of the noxious stimulus. The adoption of countermeasures to counteract the OSP progression and reduce the algic component appears to be necessary, providing patients with a better quality of life and greater adherence to treatment. In addition, the development of multimodal therapies, based on an interdisciplinary approach, appears to be crucial, combining the use of anti-osteoporotic drugs with an educational programme, regular physical activity, and proper nutrition to eliminate risk factors. Based on this evidence, we conducted a narrative review using the PubMed and Google Scholar search engines to summarize the current knowledge on the molecular mechanisms involved in the pain development in OSP and the potential countermeasures to be taken. The lack of studies addressing this topic highlights the need to conduct new research into the resolution of an ever-expanding social problem.

Role of the Osteocyte in Musculoskeletal Disease

PURPOSE OF THE REVIEW

The purpose of this review is to summarize the role of the osteocyte in muscle atrophy in cancer patients, sarcopenia, spinal cord injury, Duchenne's muscular dystrophy, and other conditions associated with muscle deterioration.

RECENT FINDINGS

One type of bone cell, the osteocyte, appears to play a major role in muscle and bone crosstalk, whether physiological or pathological. Osteocytes are cells living within the bone-mineralized matrix. These cells are connected to each other by means of dendrites to create an intricately connected network. The osteocyte network has been shown to respond to different types of stimuli such as mechanical unloading, immobilization, aging, and cancer by producing osteocytes-derived factors. It is now becoming clear that some of these factors including sclerostin, RANKL, TGF-β, and TNF-α have detrimental effects on skeletal muscle. Bone and muscle not only communicate mechanically but also biochemically. Osteocyte-derived factors appear to contribute to the pathogenesis of muscle disease and could be used as a cellular target for new therapeutic approaches.

Denosumab and incidence of type 2 diabetes among adults with osteoporosis: population based cohort study

OBJECTIVE

To estimate the effect of denosumab compared with oral bisphosphonates on reducing the risk of type 2 diabetes in adults with osteoporosis.

DESIGN

Population based study involving emulation of a randomized target trial using electronic health records.

SETTING

IQVIA Medical Research Data primary care database in the United Kingdom, 1995-2021.

PARTICIPANTS

Adults aged 45 years or older who used denosumab or an oral bisphosphonate for osteoporosis.

MAIN OUTCOME MEASURES

The primary outcome was incident type 2 diabetes, as defined by diagnostic codes. Cox proportional hazards models were used to estimate adjusted hazard ratios and 95% confidence intervals, comparing denosumab with oral bisphosphonates using an as treated approach.

RESULTS

4301 new users of denosumab were matched on propensity score to 21 038 users of an oral bisphosphonate and followed for a mean of 2.2 years. The incidence rate of type 2 diabetes in denosumab users was 5.7 (95% confidence interval 4.3 to 7.3) per 1000 person years and in oral bisphosphonate users was 8.3 (7.4 to 9.2) per 1000 person years. Initiation of denosumab was associated with a reduced risk of type 2 diabetes (hazard ratio 0.68, 95% confidence interval 0.52 to 0.89). Participants with prediabetes appeared to benefit more from denosumab compared with an oral bisphosphonate (hazard ratio 0.54, 0.35 to 0.82), as did those with a body mass index ≥30 (0.65, 0.40 to 1.06).

CONCLUSIONS

In this population based study, denosumab use was associated with a lower risk of incident type 2 diabetes compared with oral bisphosphonate use in adults with osteoporosis. This study provides evidence at a population level that denosumab may have added benefits for glucose metabolism compared with oral bisphosphonates.

Associations of estrogen therapy and non-estrogen anti-resorptive therapy with diabetes mellitus risk: A classical and Bayesian meta-analysis

Anti-resorptive therapy (AT) increases insulin resistance and decrease insulin secretion through reduced undercarboxylated osteocalcin in mice. However, there are inconsistent findings regarding the impact of AT use on the risk of diabetes mellitus in humans. We examined the association between AT and incident diabetes mellitus using classical and Bayesian meta-analysis. We searched Pubmed, Medline, Embase, Web of Science, Cochrane, and Google Scholar for studies listed from database inception to 25 February 2022. Randomized controlled trials (RCTs) and cohort studies reporting associations of estrogen therapy (ET) and non-estrogen anti-resorptive therapy (NEAT) with incident diabetes mellitus were included. Two reviewers independently extracted research data such as ET and NEAT, diabetes mellitus, risk ratios (RRs), and 95 % confidence intervals (CIs) for incident diabetes mellitus associated with ET and NEAT from individual studies. This meta-analysis included data from nineteen original studies, consisting of fourteen ET and five NEAT studies. ET was associated with reduced risk of diabetes mellitus in the classical meta-analysis (RR: 0.90; 95 % CI: 0.81-0.99). Slightly stronger results were found in the meta-analysis of RCTs (RR: 0.83; 95 % CI: 0.77-0.89). The probability that RR < 1.0 was 95 % in the overall analysis and 99 % in RCTs under weakly informative prior. Although NEAT was associated with reduced risk of diabetes mellitus overall (RR: 0.80; 95 % CI: 0.67-0.97), this was not found in the RCT meta-analysis (RR: 0.90; 95 % CI: 0.75-1.10). Under weakly informative prior, the probabilities that NEAT reduces diabetes mellitus by >0 % were 99 %, and 73 % in the overall and RCT meta-analysis, respectively. In conclusion, meta-analysis provided consistent evidence against the hypothesis that AT increases diabetes risk. ET may reduce the risk of diabetes mellitus. Whether NEAT reduces the risk of diabetes mellitus is uncertain and requires additional evidence from RCTs.

Discovering the Physio-Pathological Mechanisms of Interaction between Bone Mineral Density, Muscle Mass, and Visceral Adipose Tissue in Female Older Adults through Structural Equation Modeling

This study aims to examine the relation between visceral adipose tissue (VAT), as a proxy for metabolically unhealthy obesity, muscle, as a proxy for muscle quality and sarcopenia, and bone, as a proxy for bone mineral density and osteoporosis. Other variables, such metabolic syndrome, nutritional status, number of diseases, kidney and liver function and inflammation were assessed as direct or indirect effects. This study used structural equation modeling (SEM) in a sample of 713 older women (mean age 82.1 ± 6.3). The results indicate a positive statistically significant association between bone and muscle mass (β = 0.195, <0.001) and nutritional status and muscle mass (β = 0.139, p < 0.001), but negative association between age with muscle mass (β = −0.509, p < 0.001) and nutritional status (estimates: −2.264, p < 0.001). A negative association between VAT and muscle mass was also reported (β = −1.88, p < 0.001). A negative statistically significant association was reported between bone mineral density and functional status (β = −1.081, p < 0.001), and a positive association between functional status and muscle mass (β = 9.000, p < 0.001). In addition, functional status was positively statistically associated with cognitive performance (β = 0.032, p < 0.001). The SEM method demonstrates that the VAT, muscle mass and bone mineral density are associated, but the form of the relation is different in relation to different factors, such as nutritional status, mental and functional status, age, and number of pathologies, having different impacts on metabolic outcomes. SEM is a feasible technique for understanding the complex mechanisms of frailty in the elderly.

Mental and physical conditions associated with physical inactivity among Farhangian University students during virtual classes: A cross-sectional study

Background

The level of mobility and general health has decreased among students in virtual classes during COVID-19 pandemic. The present cross-sectional study aims to investigate the mental and physical conditions related to inactivity among the students of Farhangian University during the virtual classes.

Methods

This is a cross-sectional study. 475 students (214 females and 261 males) were selected as the statistical sample of the study based on Morgan's Table from Farhangian University, Iran. The statistical population includes students studying at Farhangian University of Mazandaran province that using Convenience Sampling the sample size based on Morgan's Table, 475 students consisting of 214 females and 261 males were randomly selected as the statistical sample of the study. The research instruments of this study include International Physical Activity Questionnaire, Saehan Caliper (SH5020), Coopersmith Self-Esteem Scale, Beck Depression Questionnaire, and Nordic Skeletal and Muscular Disorders Questionnaire. For data analysis, independent sample t-test was employed to compare two groups. All analyses were conducted using spss24 software.

Results

With respect to students' skeletal-muscular disorders, findings proved that both genders suffered physical conditions during virtual classes. The research findings showed that the average weekly activity level among women is 634 Met/min with a standard deviation of ±281, and the average weekly activity level among men is 472 Met/min with a standard deviation of ±231. Fat percentage by gender, men's average fat percentage is 47.21% (S. D ± 4.74) and women's average fat percentage is 31.55% (S. D ± 4.37). Also, the self-esteem scores of male and female students were obtained 29.72 and 29.43, respectively, and the difference between the two was considered significant (p < 0.05). On the other hand, 67% (No. 25) of female students and 32% (No. 12) of male students suffered from high depression. Also, based on students' skeletal-muscular disorders, findings of our study showed that both genders suffered physical conditions during virtual classes.

Conclusion

This study suggests increasing the level of physical activity to reduce body fat mass, increase mental health and reduce skeletal disorders, which can be properly accomplished through university planning and prioritizing the health of male and female students.

Denosumab's Therapeutic Effect for Future Osteosarcopenia Therapy : A Systematic Review and Meta-Analysis

BACKGROUND

Osteosarcopenia, a combination of osteopenia/osteoporosis and sarcopenia, is a common condition among older adults. While numerous studies and meta-analyses have been conducted on the treatment of osteoporosis, the pharmacological treatment of osteosarcopenia still lacks evidence. Denosumab, a human monoclonal antibody, has shown encouraging results for the treatment of osteosarcopenia. Our systematic review and meta-analysis aimed to investigate the potential dual role of denosumab as an anti-resorptive agent and for other beneficial muscle-related effects in patients with osteosarcopenia, and to evaluate whether denosumab can be a treatment of choice compared to bisphosphonate.

METHODS

Relevant literature was collated from the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, and Google Scholar databases. The primary outcome was denosumab's effect on lumbar spine bone mineral density (LS BMD), handgrip strength, and gait speed change. The secondary outcome was the effect of denosumab on appendicular lean mass (ALM). The outcomes were presented as mean difference (MD). A random effects model was used in the analysis to represent the population. The risk of bias was assessed using funnel plots.

RESULTS

Out of the 3,074 studies found, four full-text studies met the inclusion criteria, including 264 and 244 participants in the intervention and control groups, respectively. Regarding a primary outcome, our meta-analysis showed that denosumab showed no significant differences in LS BMD and gait speed changes compared to other agents-MD=0.37, 95% confidence interval (CI), -0.35 to 0.79; p=0.09 and MD=0.11; 95% CI, -0.18 to 0.40; p=0.46, respectively. Denosumab had a significant effect on handgrip strength change compared to standard agents-MD=5.16; 95% CI, 1.38 to 18.94; p=0.007, based on the random effects model.

CONCLUSIONS

Denosumab was better than bisphosphonate and placebo in improving muscle strength (handgrip strength). Therefore, denosumab may be favored in individuals with osteosarcopenia to improve muscular performance and reduce fall risk.

Probucol suppresses osteoclastogenesis via activating Nrf2 signaling and ameliorates ovariectomy-induced bone loss

Osteoporosis is a systemic and endocrine bone disorder distinguished by declined bone mineral density, compromised bone strength, and destruction of trabecular structure. The abnormally excessive osteoclastogenesis and bone erosion play imperative roles in the progression of osteoporosis. However, treatment of osteoporosis is far from satisfactory due to poor adherence to existing medications and adverse reactions, there is an urgent to develop novel therapies for osteoporosis. Probucol, a synthetic compound with two characteristic phenolic rings, owns anti-inflammatory and antioxidant properties. Accumulating evidence have indicated that intracellular reactive oxygen species (ROS) is closely related to osteoclastogenesis. Hence, we investigated the potential effects of probucol on osteoclastogenesis in vivo and in vitro. In this study, TRAP staining and bone slice resorption assay showed that probucol suppressed RANKL-induced osteoclast formation and function. The mRNA and protein levels of osteoclastogenesis marker genes were reduced by probucol in a concentration-dependent manner. Besides, probucol suppressed osteoclast differentiation by inhibiting ROS production, MAPKs and NF-κB signaling pathways, while Nrf2 silencing reversed the inhibitory effect of probucol on osteoclast formation and function. Consistent with the above findings, in vivo experiments demonstrated that probucol visibly alleviated bone loss caused by estrogen deficiency. In brief, these results showed the potential of anti-oxidant compound probucol in the treatment of osteoporosis, highlighting Nrf2 as a promising target in osteoclast-related disease.

Post-fracture care program in Egypt: merging subsequent fracture prevention and improving patients’ outcomes—an initiative by the Egyptian Academy of Bone Health

Background

Despite the associated high prevalence of morbidity and mortality, osteoporotic fragility fractures remain underdiagnosed and undertreated. Furthermore, those who sustain a fragility fracture are at imminent risk of sustaining subsequent fractures. Post-fracture care (PFC) programs are systematic, coordinated care programs that recognize, evaluate, and manage older adults who sustained a fragility fracture with the goal of managing all the risk factors and preventing succeeding fractures.

Main text

This work was carried out to outline the PFC program adopted in Egypt and its applicability in standard clinical practice. A review of literature was conducted to identify an evidence-informed PFC strategies and protocols, which outlines the optimal manner to manage older adults living with fragility fractures. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist was used to guide the reporting of this review. Based on this, a PFC integrated model of care based on a patient-centered approach has been developed aiming to optimize the outcomes.

Conclusion

This manuscript described the integrated model of care adopted in Egypt to provide care for older adults presenting with fragility fractures. This will pave the way to standardize patient identification and management. Additionally, to prevent occurrence of subsequent fractures and to enhance equity of care for patients with fragility fracture and osteoporosis, expansion of such service to rural and remote areas is highly recommended.

Osteopenia Is Associated with Shorter Survival in Patients with Intrahepatic Cholangiocarcinoma

BACKGROUND

The prognostic importance of osteopenia in patients with intrahepatic cholangiocarcinoma (ICC) undergoing hepatectomy is unclear. The aim of this study was to evaluate the impact of osteopenia on survival in patients with ICC.

METHODS

A total of 71 patients who underwent hepatectomy at Jichi Medical University between July 2008 and June 2022 were included in this study. Non-contrast computed tomography scan images at the eleventh thoracic vertebra were used to assess bone mineral density. The cutoff value was calculated using a threshold value of 160 Hounsfield units. Overall survival curves were made using the Kaplan-Meier method and the log-rank test was used to evaluate survival. The hazard ratio (HR) and 95% confidence interval (CI) for overall survival were calculated using Cox's proportional hazard model.

RESULTS

In multivariable analysis, osteopenia (HR 3.66, 95%CI 1.16-14.1, p = 0.0258) and the platelet-lymphocyte ratio (HR 6.26, 95%CI 2.27-15.9, p = 0.0008) were significant independent factors associated with overall survival. There were no significant independent prognostic factors for recurrence-free survival.

CONCLUSIONS

Preoperative osteopenia is significantly associated with postoperative survival in patients with ICC undergoing hepatectomy.

RANKL Is Independently Associated with Increased Risks of Non-Alcoholic Fatty Liver Disease in Chinese Women with PCOS: A Cross-Sectional Study

Women with polycystic ovarian syndrome (PCOS) are more likely to have non-alcoholic fatty liver disease (NAFLD) than non-PCOS women; however, the exact mechanism underlying this trend is unknown. The receptor activator of NF-κB ligand (RANKL) is strongly involved in bone metabolism and has multiple functions. Recent studies suggest that RANKL is implicated in hepatic insulin resistance (IR), which is the highest risk factor for NAFLD. This study aimed to assess the role of RANKL in NAFLD in Chinese women with PCOS. A cross-sectional observational study was conducted on women newly diagnosed with PCOS, which included 146 patients with NAFLD and 142 patients without NAFLD. Sex hormones, glucose, insulin, and lipids were measured, and anthropometric data were collected. The concentration of serum total RANKL was measured using commercial ELISA kits. PCOS patients with NAFLD had a significantly higher mean age, body mass index (BMI), waist circumference (WC), and worsened metabolic profile than non-NAFLD subjects. The concentrations of high-sensitivity C-reactive protein, total cholesterol, and low-density lipoprotein cholesterol increased with the RANKL tertile (p for trend = 0.023, 0.026, and 0.035, respectively). A significantly positive association was found between RANKL (per SD change) and the risks of NAFLD (OR = 1.545, 95% CI = 1.086−2.199) after adjusting for confounders, including demographic factors, metabolic markers, and sex hormones. Subgroup multivariate logistic analyses stratified by age, BMI, and WC showed the same tendency. In addition, the positive association between RANKL and NAFLD seemed more prominent in lean patients with a BMI < 24 kg/m2 (OR = 1.70, 95% CI = 1.06−2.75) when compared to overweight/obesity subjects. Therefore, this study suggests that RANKL is positively associated with the increased risk of NAFLD in Chinese women with PCOS, independent of metabolic and reproductive factors.

Delayed denervation-induced muscle atrophy in Opg knockout mice

Recent evidence has shown a crucial role for the osteoprotegerin/receptor activator of nuclear factor κ-B ligand/RANK (OPG/RANKL/RANK) signaling axis not only in bone but also in muscle tissue; however, there is still a lack of understanding of its effects on muscle atrophy. Here, we found that denervated Opg knockout mice displayed better functional recovery and delayed muscle atrophy, especially in a specific type IIB fiber. Moreover, OPG deficiency promoted milder activation of the ubiquitin-proteasome pathway, which further verified the protective role of Opg knockout in denervated muscle damage. Furthermore, transcriptome sequencing indicated that Opg knockout upregulated the expression of Inpp5k, Rbm3, and Tet2 and downregulated that of Deptor in denervated muscle. In vitro experiments revealed that satellite cells derived from Opg knockout mice displayed a better differentiation ability than those acquired from wild-type littermates. Higher expression levels of Tet2 were also observed in satellite cells derived from Opg knockout mice, which provided a possible mechanistic basis for the protective effects of Opg knockout on muscle atrophy. Taken together, our findings uncover the novel role of Opg in muscle atrophy process and extend the current understanding in the OPG/RANKL/RANK signaling axis.

Crosstalk between bone and muscle in chronic kidney disease

With increasing life expectancy, the related disorders of bone loss, metabolic dysregulation and sarcopenia have become major health threats to the elderly. Each of these conditions is prevalent in patients with chronic kidney disease (CKD), particularly in more advanced stages. Our current understanding of the bone-muscle interaction is beyond mechanical coupling, where bone and muscle have been identified as interrelated secretory organs, and regulation of both bone and muscle metabolism occurs through osteokines and myokines via autocrine, paracrine and endocrine systems. This review appraises the current knowledge regarding biochemical crosstalk between bone and muscle, and considers recent progress related to the role of osteokines and myokines in CKD, including modulatory effects of physical exercise and potential therapeutic targets to improve musculoskeletal health in CKD patients.

[Impact of osteoporosis on physical performance parameters of middle-aged and elderly individuals-a cross-sectional study]

BACKGROUND

Osteoporosis (OP) in the elderly is accompanied by reduced muscle mass and reduced muscle strength, also known as sarcopenia. This results in functional limitations and a high risk of falls and injuries. The determination of physical performance parameters such as grip strength and trunk strength on the one hand, and balance abilities on the other, provide information about the individual's general neuromuscular condition and serve as an indicator of physical performance in the elderly. The extent to which previous osteoporotic vertebral fractures (VFs) restrict an individual's physical performance has not been adequately investigated yet.

MATERIAL AND METHODS

In total, 118 persons, with a mean age of 71.5 ± 9 years, participated in the clinical trial (ethics committee approval number A2020-0041). Patients were divided into an OP group (58 patients) and a control group (CG; 60 patients). OP patients with (VFs) and without vertebral fractures (0VFs) were viewed separately in the subgroup analysis. Data concerning physical status, including hand grip strength (HGS), the chair-rising test (CRT), tandem stance (TS), tandem gait (TG), and single-leg stance (SLS) were available for all patients. All data were analyzed using SPSS, Version 23.0.

RESULTS

No significant difference (p > 0.05) was registered between the OP and CG groups with regard of HGS, CRT, TG, TS, and SLS. In the subgroup analysis, OP patients with VFs had a lower HGS than OP patients without 0 VFx (VFs 24.3 ± 10.2 kg vs. 0 VFs 29.7 ± 9.5 kg, p = 0.026). TS was maintained longer by OP patients 0 VFs (VFs 7.8 ± 3.2 s vs. 0 VFs 9.5 ± 1.8 s, p = 0.008). The latter were also able to maintain their balance in TG over more numerous steps (VFs 4.8 ± 3.0 vs. 0 VFs 6.7 ± 2.4, p = 0.011). In a regression analysis, body size, gender, and age were shown to be independent factors influencing HGS (p < 0.001).

CONCLUSION

Patient age, constitution, and gender have a relevant influence on HGS, with baseline conditions after diagnosed OP at comparable levels in this age group. In a subgroup of OP patients with VFs, there is a close relationship between bone and muscle with an increasing deterioration of the musculoskeletal system. For prophylaxis of osteosarcopenia, early training seems reasonable.

Bone-Muscle Crosstalk: Musculoskeletal Complications of Chemotherapy

PURPOSE OF REVIEW

Chemotherapy drugs combat tumor cells and reduce metastasis. However, a significant side effect of some chemotherapy strategies is loss of skeletal muscle and bone. In cancer patients, maintenance of lean tissue is a positive prognostic indicator of outcomes and helps to minimize the toxicity associated with chemotherapy. Bone-muscle crosstalk plays an important role in the function of the musculoskeletal system and this review will focus on recent findings in preclinical and clinical studies that shed light on chemotherapy-induced bone-muscle crosstalk.

RECENT FINDINGS

Chemotherapy-induced loss of bone and skeletal muscle are important clinical problems. Bone antiresorptive drugs prevent skeletal muscle weakness in preclinical models. Chemotherapy-induced loss of bone can cause muscle weakness through both changes in endocrine signaling and mechanical loading between muscle and bone. Chemotherapy-induced changes to bone-muscle crosstalk have implications for treatment strategies and patient quality of life. Recent findings have begun to determine the role of chemotherapy in bone-muscle crosstalk and this review summarizes the most relevant clinical and preclinical studies.

Sarcopenia and bone health: new acquisitions for a firm liaison

Osteosarcopenia (OS) is a newly defined condition represented by the simultaneous presence of osteopenia/osteoporosis and sarcopenia, the main age-related diseases. The simultaneous coexistence of the two phenotypes derives from the close connection of the main target tissues involved in their pathogenesis: bone and muscle. These two actors constitute the bone-muscle unit, which communicates through a biochemical and mechanical crosstalk which involves multiple factors. Altered pattern of molecular pathways leads to an impairment of both the functionality of the tissue itself and the communication with the complementary tissue, composing the OS pathogenesis. Recent advances in the genetics field have provided the opportunity to delve deeper into the complex biological and molecular mechanisms underlying OS. Unfortunately, there are still many gaps in our understanding of these pathways, but it has proven essential to apply strategies such as exercise and nutritional intervention to counteract OS. New therapeutic strategies that simultaneously target bone and muscle tissue are limited, but recently new targets for the development of dual-action drug therapies have been identified. This narrative review aims to provide an overview of the latest scientific evidence associated with OS, a complex disorder that will pave the way for future research aimed at understanding the bone-muscle-associated pathogenetic mechanisms.

The inflammatory response, a mixed blessing for muscle homeostasis and plasticity

Skeletal muscle makes up almost half the body weight of heathy individuals and is involved in several vital functions, including breathing, thermogenesis, metabolism, and locomotion. Skeletal muscle exhibits enormous plasticity with its capacity to adapt to stimuli such as changes in mechanical loading, nutritional interventions, or environmental factors (oxidative stress, inflammation, and endocrine changes). Satellite cells and timely recruited inflammatory cells are key actors in muscle homeostasis, injury, and repair processes. Conversely, uncontrolled recruitment of inflammatory cells or chronic inflammatory processes leads to muscle atrophy, fibrosis and, ultimately, impairment of muscle function. Muscle atrophy and loss of function are reported to occur either in physiological situations such as aging, cast immobilization, and prolonged bed rest, as well as in many pathological situations, including cancers, muscular dystrophies, and several other chronic illnesses. In this review, we highlight recent discoveries with respect to the molecular mechanisms leading to muscle atrophy caused by modified mechanical loading, aging, and diseases. We also summarize current perspectives suggesting that the inflammatory process in muscle homeostasis and repair is a double-edged sword. Lastly, we review recent therapeutic approaches for treating muscle wasting disorders, with a focus on the RANK/RANKL/OPG pathway and its involvement in muscle inflammation, protection and regeneration processes.

Diabetes and bone

Globally, one in 11 adults has diabetes mellitus of which 90% have type 2 diabetes. The numbers for osteoporosis are no less staggering: 1 in 3 women has a fracture after menopause, and the same is true for 1 in 5 men after the age of 50 years. Aging is associated with several physiological changes that cause insulin resistance and impaired insulin secretion, which in turn lead to hyperglycemia. The negative balance between bone resorption and formation is a natural process that appears after the fourth decade of life and lasts for the following decades, eroding the bone structure and increasing the risk of fractures. Not incidentally, it has been acknowledged that diabetes mellitus, regardless of whether type 1 or 2, is associated with an increased risk of fracture. The nuances that differentiate bone damage in the two main forms of diabetes are part of the intrinsic heterogeneity of diabetes, which is enhanced when associated with a condition as complex as osteoporosis. This narrative review addresses the main parameters related to the increased risk of fractures in individuals with diabetes, and the mutual factors affecting the treatment of diabetes mellitus and osteoporosis.

Denosumab for Prevention of Acute Onset Immobilization-Induced Alterations of Bone Turnover: A Randomized Controlled Trial

Metabolic bone disease is a devastating condition in critically ill patients admitted to an intensive care unit (ICU). We investigated the effects of early administration of the antiresorptive drug denosumab on bone metabolism in previously healthy patients. Fourteen patients with severe intracerebral or subarachnoid hemorrhage were included in a phase 2 trial. Within 72 hours after ICU admission, they were randomized in a 1:1 ratio to receive denosumab 60 mg or placebo subcutaneously. The primary endpoint was group differences in the percentage change of C-terminal telopeptide of type 1 collagen (CTX-1) levels in serum from denosumab/placebo application to 4 weeks thereafter. Changes in serum levels of bone formation markers and urinary calcium excretion were secondary outcome parameters. Regarding serum levels of CTX-1, changes over time averaged -0.45 ng/mL (95% confidence interval [CI] -0.72, -0.18) for the denosumab group and 0.29 ng/mL (95% CI -0.01, 0.58) for the placebo group. The primary endpoint, the group difference in changes between baseline and secondary measurement, adjusted for baseline serum levels and baseline neurological status, averaged -0.74 ng/mL (95% CI -1.14, -0.34; p = 0.002). The group difference in changes between baseline and secondary osteocalcin measurement averaged -5.60 ng/mL (95% CI -11.2, -0.04; p = 0.049). The group difference in averaged change between baseline and secondary measurement of 24-hour urine calcium excretion was significant (-1.77 mmol/L [95% CI -3.48, -0.06; p = 0.044]). No adverse events could be attributed to the study medication. The investigation proved that a single application of denosumab early after admission to an ICU prevents acute immobilization-associated increase in bone resorption among previously healthy individuals. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Based on CT at the third lumbar spine level, the skeletal muscle index and psoas muscle index can predict osteoporosis

Background

With the increasing number of studies on osteoporosis and muscle adipose tissue, existing studies have shown that skeletal muscle tissue and adipose tissue are closely related to osteoporosis by dual-energy x-ray absorptiometry (DXA) measurement. However, few studies have explored whether the skeletal muscle and adipose tissue index measured at the lumbar spine 3 (L3) level are closely related to bone mineral density (BMD) and can even predict osteoporosis. Therefore, this study aimed to prove whether skeletal muscle and adipose tissue index measured by computed tomography (CT) images based on a single layer are closely related to BMD.

Methods

A total of 180 participants were enrolled in this study to obtain skeletal muscle index (SMI), psoas muscle index (PMI), subcutaneous fat index (SFI), visceral fat index (VFI), and the visceral-to-subcutaneous ratio of the fat area (VSR) at L3 levels and divide them into osteoporotic and normal groups based on the T-score of DXA. Spearman rank correlation was used to analyze the correlation between SMI, PMI, SFI, VFI, VSR, and BMD. Similarly, spearman rank correlation was also used to analyze the correlation between SMI, PMI, SFI, VFI, VSR, and the fracture risk assessment tool (FRAX). Receiver operating characteristic (ROC) was used to analyze the efficacy of SMI, PMI, SFI, VFI, and VSR in predicting osteoporosis.

Results

BMD of L1-4 was closely correlated with SMI, PMI, VFI and VSR (r = 0.199 p = 0.008, r = 0.422 p < 0.001, r = 0.253 p = 0.001, r = 0.310 p < 0.001). BMD of the femoral neck was only correlated with PMI and SFI (r = 0.268 p < 0.001, r = − 0.164 p-0.028). FRAX (major osteoporotic fracture) was only closely related to PMI (r = − 0.397 p < 0.001). FRAX (hip fracture) was closely related to SMI and PMI (r = − 0.183 p = 0.014, r = − 0.353 p < 0.001). Besides, FRAX (major osteoporotic fracture and hip fracture) did not correlate with VFI, SFI, and VSR. SMI and PMI were statistically significant, with the area under the curve (AUC) of 0.400 (95% confidence interval 0.312-0.488 p = 0.024) and 0.327 (95% confidence interval 0.244-0.410 p < 0.001), respectively. VFI, SFI, and VSR were not statistically significant in predicting osteoporosis.

Conclusions

This study demonstrated that L3-based muscle index could assist clinicians in the diagnosis of osteoporosis to a certain extent, and PMI is superior to SMI in the diagnosis of osteoporosis. In addition, VFI, SFI, and VSR do not help clinicians to diagnose osteoporosis well.

Application of machine learning model to predict osteoporosis based on abdominal computed tomography images of the psoas muscle: a retrospective study

BACKGROUND

With rapid economic development, the world's average life expectancy is increasing, leading to the increasing prevalence of osteoporosis worldwide. However, due to the complexity and high cost of dual-energy x-ray absorptiometry (DXA) examination, DXA has not been widely used to diagnose osteoporosis. In addition, studies have shown that the psoas index measured at the third lumbar spine (L3) level is closely related to bone mineral density (BMD) and has an excellent predictive effect on osteoporosis. Therefore, this study developed a variety of machine learning (ML) models based on psoas muscle tissue at the L3 level of unenhanced abdominal computed tomography (CT) to predict osteoporosis.

METHODS

Medical professionals collected the CT images and the clinical characteristics data of patients over 40 years old who underwent DXA and abdominal CT examination in the Second Affiliated Hospital of Wenzhou Medical University database from January 2017 to January 2021. Using 3D Slicer software based on horizontal CT images of the L3, the specialist delineated three layers of the region of interest (ROI) along the bilateral psoas muscle edges. The PyRadiomics package in Python was used to extract the features of ROI. Then Mann-Whitney U test and the least absolute shrinkage and selection operator (LASSO) algorithm were used to reduce the dimension of the extracted features. Finally, six machine learning models, Gaussian naïve Bayes (GNB), random forest (RF), logistic regression (LR), support vector machines (SVM), Gradient boosting machine (GBM), and Extreme gradient boosting (XGBoost), were applied to train and validate these features to predict osteoporosis.

RESULTS

A total of 172 participants met the inclusion and exclusion criteria for the study. 82 participants were enrolled in the osteoporosis group, and 90 were in the non-osteoporosis group. Moreover, the two groups had no significant differences in age, BMI, sex, smoking, drinking, hypertension, and diabetes. Besides, 826 radiomic features were obtained from unenhanced abdominal CT images of osteoporotic and non-osteoporotic patients. Five hundred fifty radiomic features were screened out of 826 by the Mann-Whitney U test. Finally, 16 significant radiomic features were obtained by the LASSO algorithm. These 16 radiomic features were incorporated into six traditional machine learning models (GBM, GNB, LR, RF, SVM, and XGB). All six machine learning models could predict osteoporosis well in the validation set, with the area under the receiver operating characteristic (AUROC) values greater than or equal to 0.8. GBM is more effective in predicting osteoporosis, whose AUROC was 0.86, sensitivity 0.70, specificity 0.92, and accuracy 0.81 in validation sets.

CONCLUSION

We developed six machine learning models to predict osteoporosis based on psoas muscle images of abdominal CT, and the GBM model had the best predictive performance. GBM model can better help clinicians to diagnose osteoporosis and provide timely anti-osteoporosis treatment for patients. In the future, the research team will strive to include participants from multiple institutions to conduct external validation of the ML model of this study.

Effects of zoledronate on bone mineral density and bone turnover after long-term denosumab therapy: Observations in a real-world setting

BACKGROUND

The rebound effect after denosumab discontinuation is lessened with subsequent zoledronate therapy. However, it is unclear whether this mitigation is sufficient after long-term denosumab treatment.

OBJECTIVE

This retrospective observational study analysed bone mineral density (BMD) and bone turnover marker (BTM) changes after denosumab therapy according to treatment duration and subsequent zoledronate regimen.

METHODS

We measured the outcomes of 282 women with postmenopausal osteoporosis who discontinued denosumab and received zoledronate 6 months later. In patients with longer denosumab therapy (≥5 years), BTMs were measured every 3 months and a second zoledronate infusion was administered if BTM levels increased by ≥2-fold. The BMD of all women was measured before denosumab therapy, at the last injection and 1 to 2 years after the first zoledronate.

RESULTS

Bone loss after switching from denosumab to zoledronate was higher in patients with 10 ± 2 denosumab injections (n = 84) compared to 5 ± 2 injections (n = 144, p < 0.001 for lumbar spine and femoral neck), but there was no further increase with treatment durations of ≥15 ± 2 injections (n = 54, p = 0.35 and p = 0.20, respectively). BTMs in patients with ≥10 denosumab injections were elevated 6 months after zoledronate in some patients, but not all. Twenty-four women received a second zoledronate dose 6 months after the first one. BTMs in these patients were subsequently lower, but bone loss at both the lumbar spine and hip was comparable to that in patients with only one zoledronate dose (p = 0.37 for lumbar spine and p = 0.97 for femoral neck).

CONCLUSIONS

Rebound-associated bone loss reached a plateau after denosumab treatment durations of 4-6 years, irrespective of the frequency of subsequent zoledronate therapy.

Beneficial effects of denosumab on muscle performance in patients with low BMD: a retrospective, propensity score-matched study

This study examined the effects of denosumab compared to bisphosphonates and vitamin D alone on muscle performance in patients with low BMD. While grip force improved in both the denosumab and bisphosphonate group, a superior increase in chair rising test force was observed in the denosumab group.

INTRODUCTION

The aim of this study was to investigate the effect of the anti-resorptive agent denosumab (Dmab) on upper and lower limb muscle performance compared to bisphosphonate (BP) treatment and vitamin D supplementation alone (i.e., basic therapy) in patients with low BMD.

METHODS

This retrospective, propensity score-matched (sex, age, BMI, follow-up time) cohort study included 150 osteopenic or osteoporotic patients receiving basic (n = 60), BP (n = 30) or Dmab (n = 60) therapy. All patients underwent a musculoskeletal assessment at baseline and follow-up, including DXA, laboratory bone metabolism parameters, grip force, and chair rising test mechanography. Mean annual percentage changes were calculated and compared between study groups.

RESULTS

After a mean follow-up period of 17.6 ± 9.0 months, a significantly higher increase in grip force in both the Dmab (p < 0.001) and BP group (p = 0.001) compared to the vitamin D group was observed (vitamin D =  - 6.1 ± 10.2%; BP =  + 0.8 ± 8.2%; Dmab =  + 5.1 ± 25.5%). The Dmab group showed a significantly higher increase in chair rising test force compared to the BP group (vitamin D =  + 5.8 ± 12.7%; BP =  + 0.9 ± 8.6%; Dmab =  + 8.2 ± 14.4%; Dmab vs. BP p = 0.03). Neither the changes in BMD nor in bone metabolic parameters were associated with changes in muscle performance.

CONCLUSION

Dmab resulted in increased muscle strength in the upper and lower limbs, indicating systemic rather than site-specific effects as compared to BP. Based on these findings, Dmab might be favored over other osteoporosis treatments in patients with low BMD and poor muscle strength.

Compartment-specific effects of muscle strength on bone microarchitecture in women at high risk of osteoporosis

BACKGROUND

It is well known that skeletal integrity is influenced by the musculature. Poor muscle strength (i.e. sarcopenia) is considered a major predictor of fragility fractures. While this observation appears particularly relevant for older women with increased risk of osteoporosis, there has been no comprehensive investigation to determine the influence of muscle performance on compartment-specific bone microarchitecture in multiple body regions.

METHODS

We retrospectively analysed data from different muscle performance and bone microarchitecture assessments in 230 women (aged 21 to 87 years) at high risk of osteoporosis. Muscle performance tests included grip strength and chair rising test (CRT) combined with mechanography. Balance was determined by Romberg posturography. Areal bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine. Compartment-specific volumetric BMD, microarchitecture, and geometry were assessed by second-generation high-resolution peripheral quantitative computed tomography (HR-pQCT) at multiple skeletal sites (distal radius, tibia, and fibula). Regression models were applied to test for interactions between muscle and bone parameters. Subgroups were defined to compare women with osteoporosis and osteosarcopenia regarding BMD and microarchitecture.

RESULTS

While osteoporosis was diagnosed in 115/230 (50.0%) women, sarcopenia was detected in 38/230 (16.5%). Positive associations of both grip strength and CRT maximum force with cortical geometric and microarchitectural parameters were detected at all measured sites, with the strongest effect applying to CRT maximum force and tibial parameters (e.g. tibial cortical area R2  = 0.36, P < 0.0001, and tibial cortical thickness R2  = 0.26, P < 0.0001). Balance parameters showed much weaker or no associations with HR-pQCT parameters. Major associations between muscle strength and trabecular parameters could not be confirmed. Age and body mass index were confirmed as negative and positive predictors for several microarchitectural parameters, respectively. An independent predictive value of grip strength on radial, tibial, and fibular (all P < 0.01) cortical area and of CRT maximum relative force on cortical thickness (all P < 0.05) was revealed. Women with osteosarcopenia showed significantly reduced cortical HR-pQCT parameters but no differences in DXA values compared with women with osteoporosis but no sarcopenia. Stratification by fracture and treatment status revealed that vertebral fractures and denosumab treatment altered the muscle-bone interaction.

CONCLUSIONS

A systemic interaction between muscle strength and bone microarchitecture was demonstrated, and this interaction appears to be primarily with the cortical bone compartment. The value of muscle assessments in fracture risk evaluation may be partly mediated by their effects on bone microarchitecture.

A bibliometric research based on hotspots and frontier trends of denosumab

Denosumab is a monoclonal antibody that targets and inhibits the osteoclast activating factor receptor activator for nuclear factor-κB ligand (RANKL). It has been widely used in the treatment of osteoporosis, giant cell tumors of bone, and in the prevention of malignant skeletal-related events (SREs). We collected the research results and related MeSH terms of denosumab from 2011 to 2021 through the Web of Science and PubMed, respectively. The literature was visualized and analyzed by CiteSpace and bibliometric online analysis platforms. The MeSH terms were biclustered using the Bibliographic Co-Occurrence Analysis System (BICOMB) and graph clustering toolkit (gCLUTO). The results show that the number of denosumab-related annual publications had increased from 51 to 215, with the United States leading and Amgen Inc. being the most influential in the past 10 years. Articles published in the Journal of Bone and Mineral Research had the highest total citations. Three scholars from Shinshu University in Matsumoto, Yukio Nakamura, Takako Suzuki, and Hiroyuki Kato, joined the field relatively late but produced the most. The clinical comparison and combination of denosumab with other drugs in the treatment of osteoporosis was the most significant focus of research. Drug withdrawal rebound and management strategies have gained more attention and controversy recently. MeSH analysis revealed eight major categories of research hotspots. Among them, exploring the multiple roles of the RANK-RANKL-OPG system in tumor progression, metastasis, and other diseases is the potential direction of future mechanism research. It is a valuable surgical topic to optimize the perioperative drug administration strategy for internal spinal fixation and orthopedic prosthesis implantation. Taken together, the advantages of denosumab were broad and cost-effective. However, there were still problems such as osteonecrosis of the jaw, severe hypocalcemia, a high recurrence rate of giant cells in the treatment of bone and individual sarcoidosis, and atypical femoral fractures, which need to be adequately solved.