Effect of Denosumab on Falls, Muscle Strength, and Function in Community-Dwelling Older Adults

The comparative effect of teriparatide and denosumab on activins, follistatins, and inhibins in women with postmenopausal osteoporosis

The activins-follistatins-inhibins (AFI) hormonal system affects bone metabolism. Treatments that alter bone metabolism may also alter the AFI molecules. In this non-randomized, open-label, head-to-head comparative study, circulating levels of the AFI system were evaluated in postmenopausal women with osteoporosis treated for 12 mo with either teriparatide (n = 23) or denosumab (n = 22). Τeriparatide treatment increased activin B (P=.01) and activin AB (P=.004) and the ratios activin A/follistatin (P=.006), activin B/follistatin (P=.007), activin AB/follistatin (P<.001), and activin AB/ follistatin-like 3 (FSTL3) (P=.034). The significant P for trend in group × time interactions of activins B and AB and of the ratio activin AB/FSTL3 remained robust after adjustment for BMI and LS BMD but it was lost for activin B after adjustment for previous antiresorptive treatment. The effect of teriparatide on BMD was attenuated when it was adjusted for baseline activins levels or their 12-mo changes. No changes were observed after denosumab treatment. In conclusion, activins B and AB, as well as the ratios of all activins to follistatin and of activin AB to FSTL3 increased with teriparatide treatment, possibly in a compensatory manner. Future studies are needed to study the potentially important role activins may play in bone biology and any associations with the effect of teriparatide on BMD. Clinical Trials identifier: NCT04206618. ClinicalTrials.gov  https://clinicaltrials.gov/search?term=NCT04206618.

Drug adherence and treatment duration for denosumab and mortality risk among hip fracture patients

This study aimed to assess the impact of drug adherence and treatment duration for denosumab on mortality risk after hip fracture surgery. Lower all-cause mortality risk was associated with drug intervals of 7 months or less and longer treatment duration. The study highlights the importance of proper denosumab administration.

PURPOSE

Prescription of anti-osteoporotic medications (AOMs) after osteoporotic hip fracture may increase bone mineral density (BMD) and decrease mortality risk. However, few studies have been conducted on drug adherence and treatment duration for denosumab, a popular choice among AOMs. This study aimed to assess the impact of denosumab adherence and treatment duration on the mortality risk of hip fracture patients after surgery.

METHODS

We conducted a cohort study using nationwide population data from National Health Insurance Research Database (NHIRD) in Taiwan. Patients newly diagnosed with osteoporosis and hip fracture between 2008 and 2019 who used denosumab after surgery were included. We assessed drug adherence, treatment duration, and other parameters associated with patient outcomes.

RESULTS

A total of 21,316 patients diagnosed with osteoporotic hip fractures were included. Compared with a > 7-month drug interval for denosumab, an interval of ≤ 7 months led to lower all-cause mortality risk (hazard ratio (HR): 0.60, 95% confidence interval (CI): 0.57 ~ 0.64). Patients with denosumab treatment for over 1, 2, and 3 years had lower all-cause mortality risk (HR&CI: 0.68 (0.64 ~ 0.73), 0.48 (0.43 ~ 0.53), 0.29 (0.26 ~ 0.33)) than those with treatment duration < 1 year. Analysis after excluding short-term death yielded similar results. Analysis of causes of death also showed that good adherence and longer duration were associated with reduced mortality due to cancer and cardiovascular disease.

CONCLUSION

Better drug adherence and longer duration of denosumab treatment are associated with lower all-cause mortality risk among hip fracture patients after surgery. Our study highlights the benefits of a proper time interval of denosumab administration. These findings provide important insight into management of osteoporotic hip fractures and may inform clinical practice and development of guidelines.

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.

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.

Proceedings of the Post-Genome Analysis for Musculoskeletal Biology Workshop

PURPOSE OF THE REVIEW

Herein, we report on the proceedings of the workshop entitled "Post-Genome analysis for musculoskeletal biology" that was held in July of 2022 in Safed, Galilee, Israel. Supported by the Israel Science Foundation, the goal of this workshop was to bring together established investigators and their trainees who were interested in understanding the etiology of musculoskeletal disease, from Israel and from around the world.

RECENT FINDINGS

Presentations at this workshop spanned the spectrum from basic science to clinical studies. A major emphasis of the discussion centered on genetic studies in humans, and the limitations and advantages of such studies. The power of coupling studies using human data with functional follow-up studies in pre-clinical models such as mice, rats, and zebrafish was discussed in depth. The advantages and limitations of mice and zebrafish for faithfully modelling aspects of human disease were debated, specifically in the context of age-related diseases such as osteoporosis, osteoarthritis, adult-onset auto-immune disease, and osteosarcopenia. There remain significant gaps in our understanding of the nature and etiology of human musculoskeletal disease. While therapies and medications exist, much work is still needed to find safe and effective interventions for all patients suffering from diseases associated with age-related deterioration of musculoskeletal tissues. The potential of forward and reverse genetic studies has not been exhausted for diseases of muscles, joints, and bones.

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.

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.

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.

Functional capacity, sarcopenia, and bone health

Bone and muscle are recognised as interacting tissues, the so-called 'muscle-bone unit', in which these two tissues communicate to coordinate their development (chemically and metabolically), as well as their response to loading or injury. Musculoskeletal disorders of ageing, specifically osteoporosis and sarcopenia, are highly prevalent in older individuals. They signify a significant burden for older people affecting their mobility, confidence, and quality of life, as well as being a major cost to healthcare systems worldwide. This review considers the coexistence of osteoporosis and sarcopenia in individuals and describes risk factors, clinical consequences, approaches to management, and the link with functional capacity.

Skeletal Aging

Aging represents the single greatest risk factor for chronic diseases, including osteoporosis, a skeletal fragility syndrome that increases fracture risk. Optimizing bone strength throughout life reduces fracture risk. Factors critical for bone strength include nutrition, physical activity, and vitamin D status, whereas unhealthy lifestyles, illnesses, and certain medications (eg, glucocorticoids) are detrimental. Hormonal status is another important determinant of skeletal health, with sex steroid concentrations, particularly estrogen, having major effects on bone remodeling. Aging exacerbates bone loss in both sexes and results in imbalanced bone resorption relative to formation; it is associated with increased marrow adiposity, osteoblast/osteocyte apoptosis, and accumulation of senescent cells. The mechanisms underlying skeletal aging are as diverse as the factors that determine the strength (and thus fragility) of bone. This review updates our current understanding of the epidemiology, pathophysiology, and treatment of osteoporosis and provides an overview of the underlying hallmark mechanisms that drive skeletal aging.

Osteosarcopenia: A Narrative Review on Clinical Studies

Osteosarcopenia (OS) is defined by the concurrent presence of osteopenia/osteoporosis and sarcopenia. The pathogenesis and etiology of OS involve genetic, biochemical, mechanical, and lifestyle factors. Moreover, an inadequate nutritional status, such as low intake of protein, vitamin D, and calcium, and a reduction in physical activity are key risk factors for OS. This review aims to increase knowledge about diagnosis, incidence, etiology, and treatment of OS through clinical studies that treat OS as a single disease. Clinical studies show the relationship between OS and the risk of frailty, falls, and fractures and some association with Non-communicable diseases (NCDs) pathologies such as diabetes, obesity, and cardiovascular disease. In some cases, the importance of deepening the related mechanisms is emphasized. Physical exercise with adequate nutrition and nutritional supplementations such as proteins, Vitamin D, or calcium, represent a significant strategy for breaking OS. In addition, pharmacological interventions may confer benefits on muscle and bone health. Both non-pharmacological and pharmacological interventions require additional randomized controlled trials (RCT) in humans to deepen the synergistic effect of exercise, nutritional interventions, and drug compounds in osteosarcopenia.

A pas de deux of osteoporosis and sarcopenia: osteosarcopenia

The musculoskeletal conditions osteoporosis and sarcopenia are highly prevalent in older adults. Osteoporosis is characterized by low bone mass and microarchitectural deterioration of bone, whereas sarcopenia is identified by the loss of muscle strength, function and mass. Osteoporosis represents a major health problem contributing to millions of fractures worldwide on an annual basis, whereas sarcopenia is associated with a range of adverse physical and metabolic outcomes. They both affect physical and social function, confidence and quality of life as well as contributing to high health-care costs worldwide. Osteosarcopenia is the term given when both conditions occur concomitantly and it has been suggested that interactions between these two conditions may accelerate individual disease progression as co-existence of osteoporosis and sarcopenia is associated with higher morbidity from falls, fracture, disability as well as mortality. In this review, we will outline the epidemiology, pathogenesis and clinical consequences of osteosarcopenia and discuss available management strategies.

Serum levels of C-terminal telopeptide (CTX) are associated with muscle function in community-dwelling older adults

BACKGROUND

Markers of bone metabolism have been associated with muscle mass and function. Whether serum cross-linked C-terminal telopeptides of type I collagen (CTX) is also associated with these measures in older adults remains unknown.

METHODS

In community-dwelling older adults at high risk of falls and fractures, serum CTX (biochemical immunoassays) was used as the exposure, while appendicular lean mass (dual-energy x-ray absorptiometry) and muscle function (grip strength [hydraulic dynamometer], short physical performance battery [SPPB], gait speed, sit to stand, balance, Timed Up and Go [TUG]) were used as outcomes. Potential covariates including demographic, lifestyle and clinical factors were considered in statistical models. Areas under the ROC curves were calculated for significant outcomes.

RESULTS

299 older adults (median age: 79 years, IQR: 73, 84; 75.6% women) were included. In multivariable models, CTX was negatively associated with SPPB (β = 0.95, 95% CI: 0.92, 0.98) and balance (β = 0.92, 0.86, 0.99) scores, and positively associated with sit to stand (β = 1.02, 95% CI: 1.00, 1.05) and TUG (β = 1.03, 95% CI: 1.00, 1.05). Trend line for gait speed (β = 0.99, 95% CI: 0.98, 1.01) was in the hypothesized direction but did not reach significance. AUC curves showed low diagnostic power (<0.7) of CTX in identifying poor muscle function (SPPB: 0.63; sit to stand: 0.64; TUG: 0.61).

CONCLUSION

In older adults, higher CTX levels were associated with poorer lower-limb muscle function (but showed poor diagnostic power for these measures). These clinical data build on the biomedical link between bone and muscle.

Osteosarcopenia School

Osteosarcopenia has been proposed as a syndrome in a subset of frail individuals at higher risk of falls, fractures and institutionalization. In this paper, we will go over the translational aspects of sarcopenia and osteoporosis research and highlight outcomes from different interventions. In addition, preventative measures and therapeutic interventions that can benefit both muscle and bone simultaneously will be analysed also. A new holistic concept called Osteosarcopenia School will be presented. This new concept is based on counselling and education of patients as part of a rehabilitation program, aiming to reduce the risk of social isolation, falls and fractures, and subsequent disability through muscle strengthening and balance training. In this patient group, the combination of pharmaceutical treatments and specific exercise programmes are essential to counteract the consequences of osteosarcopenia. Finally, educational programmes targeting patient functionality through social reintegration may have a substantial impact on their daily living activities and overall quality of life.

Pharmacologic Interventions for Fracture Risk Reduction in the Oldest Old: What Is the Evidence?

With an increasingly older population, the proportion of patients 85 years or older seeking interventions to protect their musculoskeletal health is growing. Osteoporosis in the geriatric population presents unique diagnostic and therapeutic challenges. Multimorbidity, frailty, falls, polypharmacy, and other neurobehavioral factors influence our approach to fracture prevention in this population. The vast majority of the evidence from clinical trials establish pharmacologic fracture efficacy in postmenopausal women. The evidence is scarce for the oldest old men and women, a population also at risk for adverse events and mortality. Most studies show continued efficacy of pharmacologic interventions in this age group, although they are largely limited by small sample sizes. We herein review the available evidence of pharmacologic interventions for fracture risk reduction in this population and explore the emerging senotherapeutic interventions in the pipeline. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Is there a potential dual effect of denosumab for treatment of osteoporosis and sarcopenia?

BACKGROUND

The prevalence of sarcopenia with osteoporosis results in a higher risk of falling and fractures. It was noted that patients who had completed their planned 5-year denosumab therapy course as treatment for these conditions started to sustain falls.

PURPOSE

To assess (a) whether denosumab has a unique dual effect on both bone and muscle in comparison to other anti-resorptive agents and (b) its effectiveness in the follow-up period post-treatment completion compared to other anti-resorptive agents.

METHOD

One hundred thirty-five patients diagnosed to have postmenopausal/senile osteoporosis and who were prescribed denosumab were compared to a control group of 272 patients stratified into 2 subgroups - 136 prescribed alendronate and 136 prescribed zoledronate. All patients were assessed for: BMD (DXA), falls risk (FRAS), fracture risk (FRAX), and sarcopenia measures. All were re-assessed after 5 years of denosumab/alendronate therapy and 3 years of zoledronate and 1 year after stopping the osteoporosis therapy.

RESULTS

No significant baseline demographic differences between the 3 groups. On completion of the 5-year denosumab therapy, there was significant decrease in falls risk (P = 0.001) and significant improvements in all sarcopenia measures (P = 0.01). One-year post-discontinuation of denosumab, a significant worsening of both falls risk and sarcopenia measures (P = 0.01) noticed.

CONCLUSION

Denosumab displayed positive impact and significant improvements in BMD and sarcopenia measures. It also enhanced multidirectional agility as depicted by Timed Up and Go (TUG). Collectively, this would explain the reduction of falls risk which got worse on stopping the medication. Key points • The coexistence of osteoporosis and sarcopenia has been recently considered in some groups as a syndrome termed 'osteosarcopenia'. • Bone and muscle closely interact with each other not only anatomically, but also at the chemical and metabolic levels. • Denosumab displayed positive impact and significant improvements in all sarcopenia measures, and enhanced multidirectional agility with consequent reduction in falls risk. • Denosumab can be considered as a first osteoporosis therapeutic option in this group of patients presenting with osteosarcopenia manifestations.

Vitamin D Deficiency in Older Patients-Problems of Sarcopenia, Drug Interactions, Management in Deficiency

Vitamin D deficiency frequently occurs in older people, especially in individuals with comorbidity and polypharmacotherapy. In this group, low vitamin D plasma concentration is related to osteoporosis, osteomalacia, sarcopenia and myalgia. Vitamin D levels in humans is an effect of the joint interaction of all vitamin D metabolic pathways. Therefore, all factors interfering with individual metabolic stages may affect 25-hydroxyvitamin D plasma concentration. The known factors affecting vitamin D metabolism interfere with cytochrome CYP3A4 activity. There is another group of factors that impairs intestinal vitamin D absorption. The phenomenon of drugs and vitamin D interactions is observed first and foremost in patients with comorbidity. This is a typical situation, where the absence of "hard evidence" is not synonymous with the possible lack of adverse effects. Osteoporosis and sarcopenia (generalized and progressive decrease of skeletal muscle mass and strength) are some of the musculoskeletal consequences of hypovitaminosis D. These consequences are related to an increased risk of adverse outcomes, including bone fractures, physical disabilities, and a lower quality of life. This can lead not only to an increased risk of falls and fractures but is also one of the main causes of frailty syndrome in the aging population. Generally, Vitamin D plasma concentration is significantly lower in subjects with osteoporosis and muscle deterioration. In some observational and uncontrolled treatment studies, vitamin D supplementation resulted in a reduction of proximal myopathy and muscle pain. The most conclusive results were found in subjects with severe vitamin D deficiency and in patients avoiding large doses of vitamin D. However, the role of vitamin D in muscle pathologies is not clear and research has provided conflicting results. This is plausibly due to the heterogeneity of the subjects, vitamin D doses and environmental factors. This report presents data on some problems with vitamin D deficiency in the elderly population and the management of vitamin D deficiency D in successful or unsuccessful aging.

An Overview of the Molecular Mechanisms Contributing to Musculoskeletal Disorders in Chronic Liver Disease: Osteoporosis, Sarcopenia, and Osteoporotic Sarcopenia

The prevalence of osteoporosis and sarcopenia is significantly higher in patients with liver disease than in those without liver disease and osteoporosis and sarcopenia negatively influence morbidity and mortality in liver disease, yet these musculoskeletal disorders are frequently overlooked in clinical practice for patients with chronic liver disease. The objective of this review is to provide a comprehensive understanding of the molecular mechanisms of musculoskeletal disorders accompanying the pathogenesis of liver disease. The increased bone resorption through the receptor activator of nuclear factor kappa (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) system and upregulation of inflammatory cytokines and decreased bone formation through increased bilirubin and sclerostin and lower insulin-like growth factor-1 are important mechanisms for osteoporosis in patients with liver disease. Sarcopenia is associated with insulin resistance and obesity in non-alcoholic fatty liver disease, whereas hyperammonemia, low amount of branched chain amino acids, and hypogonadism contributes to sarcopenia in liver cirrhosis. The bidirectional crosstalk between muscle and bone through myostatin, irisin, β-aminoisobutyric acid (BAIBA), osteocalcin, as well as the activation of the RANK and the Wnt/β-catenin pathways are associated with osteosarcopenia. The increased understandings for these musculoskeletal disorders would be contributes to the development of effective therapies targeting the pathophysiological mechanism involved.

A Vicious Cycle of Osteosarcopeniain Inflammatory Bowel Diseases-Aetiology, Clinical Implications and Therapeutic Perspectives

Sarcopenia is a disorder characterized by a loss of muscle mass which leads to the reduction of muscle strength and a decrease in the quality and quantity of muscle. It was previously thought that sarcopenia was specific to ageing. However, sarcopenia may affect patients suffering from chronic diseases throughout their entire lives. A decreased mass of muscle and bone is common among patients with inflammatory bowel disease (IBD). Since sarcopenia and osteoporosis are closely linked, they should be diagnosed as mutual consequences of IBD. Additionally, multidirectional treatment of sarcopenia and osteoporosis including nutrition, physical activity, and pharmacotherapy should include both disorders, referred to as osteosarcopenia.

How to Overcome Anabolic Resistance in Dialysis-Treated Patients?

A current hypothesis is that dialysis-treated patients are "anabolic resistant" i. e., their muscle protein synthesis (MPS) response to anabolic stimuli is blunted, an effect which leads to muscle wasting and poor physical performance in aging and in several chronic diseases. The importance of maintaining muscle mass and MPS is often neglected in dialysis-treated patients; better than to describe mechanisms leading to energy-protein wasting, the aim of this narrative review is to suggest possible strategies to overcome anabolic resistance in this patient's category. Food intake, in particular dietary protein, and physical activity, are the two major anabolic stimuli. Unfortunately, dialysis patients are often aged and have a sedentary behavior, all conditions which per se may induce a state of "anabolic resistance." In addition, patients on dialysis are exposed to amino acid or protein deprivation during the dialysis sessions. Unfortunately, the optimal amount and formula of protein/amino acid composition in supplements to maximixe MPS is still unknown in dialysis patients. In young healthy subjects, 20 g whey protein maximally stimulate MPS. However, recent observations suggest that dialysis patients need greater amounts of proteins than healthy subjects to maximally stimulate MPS. Since unneccesary amounts of amino acids could stimulate ureagenesis, toxins and acid production, it is urgent to obtain information on the optimal dose of proteins or amino acids/ketoacids to maximize MPS in this patients' population. In the meantime, the issue of maintaining muscle mass and function in dialysis-treated CKD patients needs not to be overlooked by the kidney community.

Exercise and Diet: Uncovering Prospective Mediators of Skeletal Fragility in Bone and Marrow Adipose Tissue

PURPOSE OF REVIEW

To highlight recent basic, translational, and clinical works demonstrating exercise and diet regulation of marrow adipose tissue (MAT) and bone and how this informs current understanding of the relationship between marrow adiposity and musculoskeletal health.

RECENT FINDINGS

Marrow adipocytes accumulate in the bone in the setting of not only hypercaloric intake (calorie excess; e.g., diet-induced obesity) but also with hypocaloric intake (calorie restriction; e.g., anorexia), despite the fact that these states affect bone differently. With hypercaloric intake, bone quantity is largely unaffected, whereas with hypocaloric intake, bone quantity and quality are greatly diminished. Voluntary running exercise in rodents was found to lower MAT and promote bone in eucaloric and hypercaloric states, while degrading bone in hypocaloric states, suggesting differential modulation of MAT and bone, dependent upon whole-body energy status. Energy status alters bone metabolism and bioenergetics via substrate availability or excess, which plays a key role in the response of bone and MAT to mechanical stimuli. Marrow adipose tissue (MAT) is a fat depot with a potential role in-as well as responsivity to-whole-body energy metabolism. Understanding the localized function of this depot in bone cell bioenergetics and substrate storage, principally in the exercised state, will aid to uncover putative therapeutic targets for skeletal fragility.

A clinical guide to the pathophysiology, diagnosis and treatment of osteosarcopenia

Advances in medicine have paved the way for older persons to live longer, but with more years spent living with disability and dependency. Many older persons are living with comorbidities such as osteoporosis (loss of bone mass) and sarcopenia (loss of muscle mass and function), two diseases that, when concurrent, form osteosarcopenia, a newly identified musculoskeletal syndrome. Osteosarcopenia impedes mobility and diminishes independence and thus quality of life. Evidence suggests the pathology of this syndrome comprises genetic polymorphisms, alterations in mechanotransduction, and localized or systemic crosstalk between growth factors and other proteins (myokines, osteokines, adipokines). As a direct result of an aging society, health outcomes such as falls and fractures will rise as the prevalence of osteosarcopenia increases. Two major risk factors for osteosarcopenia (other than age itself) are physical inactivity and poor nutrition. Addressing these modifiable risk factors can prevent, or at least delay, the onset of osteosarcopenia. Pharmaceutical treatments for osteosarcopenia are currently unavailable, although research trials are underway. This review provides an update from basic and clinical sciences on the biology, epidemiology (prevalence, risk factors and diagnosis) and treatments for osteosarcopenia, and recommends future research priorities to improve health outcomes for those living with or at risk of osteosarcopenia.

Osteosarcopenia: epidemiology, diagnosis, and treatment-facts and numbers

BACKGROUND

Osteosarcopenia, the presence of osteopenia/osteoporosis and sarcopenia, is an emerging geriatric giant, which poses a serious global health burden.

METHODS AND RESULTS

The prevalence of osteosarcopenia ranges in community-dwelling older adults [5-37% (≥65 years)] with the highest rates observed in those with fractures (low-trauma fracture: ~46%; hip fracture: 17.1-96.3%). Among 2353 community-dwelling adults, risk factors associated with osteosarcopenia include older age [men: 14.3% (60-64 years) to 59.4% (≥75 years); women: 20.3% (60-64 years) to 48.3% (≥75 years), P < 0.05], physical inactivity [inverse relationship: 0.64, 95% confidence interval (CI) 0.46-0.88 (sexes combined)], low body mass index (inverse relationship: men: 0.84, 95% CI 0.81-0.88; women: 0.77, 95% CI 0.74-0.80), and higher fat mass (men: 1.46, 95% CI 1.11-1.92; women: 2.25, 95% CI 1.71-2.95). Among 148 geriatric inpatients, osteosarcopenic individuals demonstrate poorer nutritional status (mini-nutritional assessment scores: 8.50 ± 2.52 points, P < 0.001) vs. osteoporosis or sarcopenia alone, while among 253 older Australians, osteosarcopenia is associated with impaired balance and functional capacity [odds ratios (ORs): 2.56-7.19; P < 0.05] vs. non-osteosarcopenia. Osteosarcopenia also associates with falls (ORs: 2.83-3.63; P < 0.05), fractures (ORs: 3.86-4.38; P < 0.05), and earlier death [hazard ratio (1-year follow-up): 1.84, 95% CI; 0.69-4.92, P = 0.023] vs. non-osteosarcopenia.

CONCLUSIONS

This syndrome is expected to grow in age-related and disease-related states, a likely consequence of immunosenescence coinciding with increased sedentarism, obesity, and fat infiltration of muscle and bone. Evidence suggests the pathophysiology of osteosarcopenia includes genetic polymorphisms, reduced mechanical loading, and impaired endocrine functioning, as well as altered crosstalk between muscle, bone, and fat cells. Clinicians should screen for osteosarcopenia via imaging methods (i.e. dual-energy X-ray absorptiometry) to quantify muscle and bone mass, in addition to assessing muscle strength (i.e. grip strength) and functional capacity (i.e. gait speed). A comprehensive geriatric assessment, including medical history and risk factors, must also be undertaken. Treatment of this syndrome should include osteoporotic drugs [bone anabolics/antiresorptives (i.e. teriparatide, denosumab, bisphosphates)] where indicated, and progressive resistance and balance exercises (at least 2-3 times/week). To maximize musculoskeletal health, nutritional recommendations [protein (1.2-1.5 g/kg/day), vitamin D (800-1000 IU/day), calcium (1300 mg/day), and creatine (3-5 g/day)] must also be met. It is anticipated that diagnosis and treatment for osteosarcopenia will become part of routine healthcare in the future. However, further work is required to identify biomarkers, which, in turn, may increase diagnosis, risk stratification, and targeted treatments to improve health outcomes.