Radiofrequency echographic multi spectrometry (REMS) in the diagnosis and management of osteoporosis: state of the art.

Radiofrequency Echographic Multi Spectrometry (REMS) is a radiation-free, portable technology, which can be used for the assessment and monitoring of osteoporosis at the lumbar spine and femoral neck and may facilitate wider access to axial BMD measurement compared with standard dual-energy x-ray absorptiometry (DXA).There is a growing literature demonstrating a strong correlation between DXA and REMS measures of BMD and further work supporting 5-year prediction of fracture using the REMS Fragility Score, which provides a measure of bone quality (in addition to the quantitative measure of BMD).The non-ionising radiation emitted by REMS allows it to be used in previously underserved populations including pregnant women and children and may facilitate more frequent measurement of BMD.The portability of the device means that it can be deployed to measure BMD for frail patients at the bedside (avoiding the complications in transfer and positioning which can occur with DXA), in primary care, the emergency department, low-resource settings and even at home.The current evidence base supports the technology as a useful tool in the management of osteoporosis as an alternative to DXA.

IOF position on scientists and societies operating in conflict zones.

This position paper of the International Osteoporosis Foundation reports the findings of an IOF Commission to consider to recommend rules of partnership with scientists belonging to a country which is currently responsible for an armed conflict, anywhere in the world. The findings and recommendations have been adopted unanimously by the Board of IOF.

Survey of awareness and attitudes to the management of fragility fractures among the membership of the Asia Pacific Orthopaedic Association.

A survey of awareness and attitudes to the management of fragility fractures among the membership of the Asia Pacific Orthopaedic Association conducted in 2022 found considerable variation in care across the region. A Call to Action is proposed to improve acute care, rehabilitation and secondary fracture prevention across Asia Pacific. PURPOSE: Fragility fractures impose a substantial burden on older people and their families, healthcare systems and national economies. The current incidence of hip and other fragility fractures across the Asia Pacific region is enormous and set to escalate rapidly in the coming decades. This publication describes findings of a survey of awareness and attitudes to the management of fragility fractures among the membership of the Asia Pacific Orthopaedic Association (APOA) conducted in 2022. METHODS: The survey was developed as a collaboration between the Asia Pacific Osteoporosis and Fragility Fracture Society and the Asia Pacific Fragility Fracture Alliance, and included questions relating to aspects of care upon presentation, during surgery and mobilisation, secondary fracture prevention, and access to specific services. RESULTS: In total, 521 APOA members completed the survey and marked variation in delivery of care was evident. Notable findings included: Fifty-nine percent of respondents indicated that analgesia was routinely initiated in transit (by paramedics) or within 30 minutes of arrival in the Emergency Department. One-quarter of respondents stated that more than 80% of their patients underwent surgery within 48 hours of admission. One-third of respondents considered non-hip, non-vertebral fractures to merit assessment of future fracture risk. One-third of respondents reported the presence of an Orthogeriatric Service in their hospital, and less than a quarter reported the presence of a Fracture Liaison Service. CONCLUSION: A Call to Action for all National Orthopaedic Associations affiliated with APOA is proposed to improve the care of fragility fracture patients across the region.

Evidence-Based Guideline for the management of osteoporosis in men.

Historically, osteoporosis has been viewed as a disease of women, with research, trials of interventions and guidelines predominantly focused as such. It is apparent, however, that this condition causes a substantial health burden in men also, and that its assessment and management must ultimately be addressed across both sexes. In this article, an international multidisciplinary working group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases presents GRADE-assessed recommendations for the diagnosis, monitoring and treatment of osteoporosis in men. The recommendations are based on a comprehensive review of the latest research related to diagnostic and screening approaches for osteoporosis and its associated high fracture risk in men, covering disease burden, appropriate interpretation of bone densitometry (including the use of a female reference database for densitometric diagnosis in men) and absolute fracture risk, thresholds for treatment, and interventions that can be used therapeutically and their health economic evaluation. Future work should specifically address the efficacy of anti-osteoporosis medications, including denosumab and bone-forming therapies.

Real-world evidence: new opportunities for osteoporosis research. Recommendations from a Working Group from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO).

This narrative review summarises the recommendations of a Working Group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) for the conduct and reporting of real-world evidence studies with a focus on osteoporosis research. PURPOSE: Vast amounts of data are routinely generated at every healthcare contact and activity, and there is increasing recognition that these real-world data can be analysed to generate scientific evidence. Real-world evidence (RWE) is increasingly used to delineate the natural history of disease, assess real-life drug effectiveness, understand adverse events and in health economic analysis. The aim of this work was to understand the benefits and limitations of this type of data and outline approaches to ensure that transparent and high-quality evidence is generated. METHODS: A ESCEO Working Group was convened in December 2022 to discuss the applicability of RWE to osteoporosis research and approaches to best practice. RESULTS: This narrative review summarises the agreed recommendations for the conduct and reporting of RWE studies with a focus on osteoporosis research. CONCLUSIONS: It is imperative that research using real-world data is conducted to the highest standards with close attention to limitations and biases of these data, and with transparency at all stages of study design, data acquisition and curation, analysis and reporting to increase the trustworthiness of RWE study findings.

Novel formulations of oral bisphosphonates in the treatment of osteoporosis.

Oral bisphosphonates are a key intervention in the treatment of osteoporosis and in reducing the risk of fragility fractures. Their use is supported by over 3 decades of evidence; however, patient adherence to oral bisphosphonates remains poor in part due to complex dosing instructions and adverse events, including upper gastrointestinal symptoms. This problem has led to the development of novel oral bisphosphonate formulations. Buffered, effervescent alendronate is dissolved in water and so seeks to reduce upper gastro-intestinal adverse events, and gastro-resistant risedronate aims to reduce the complexity of dosing procedure (e.g. fasting prior to consumption) whilst still maintaining the efficacy of fracture risk reduction. Clinical trials and real-world data have been employed to demonstrate some benefits in terms of reduced upper gastro-intestinal adverse events, adherence, persistence and health economic outcomes. This report describes the result of an ESCEO (European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis) expert working group, which explores where oral bisphosphonates sit in current clinical practice guidelines, review their risk-benefit profile and the consequences of poor adherence before exploring novel oral bisphosphonate formulations and their potential clinical and health economic impact. Further research is required but there are signs that these novel, oral bisphosphonate formulations may lead to improved tolerance of oral bisphosphonates and thus, improved adherence and fracture outcomes.

Role of vitamin D supplementation in the management of musculoskeletal diseases: update from an European Society of Clinical and Economical Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) working group.

Vitamin D is a key component for optimal growth and for calcium-phosphate homeostasis. Skin photosynthesis is the main source of vitamin D. Limited sun exposure and insufficient dietary vitamin D supply justify vitamin D supplementation in certain age groups. In older adults, recommended doses for vitamin D supplementation vary between 200 and 2000 IU/day, to achieve a goal of circulating 25-hydroxyvitamin D (calcifediol) of at least 50 nmol/L. The target level depends on the population being supplemented, the assessed system, and the outcome. Several recent large randomized trials with oral vitamin D regimens varying between 2000 and 100,000 IU/month and mostly conducted in vitamin D-replete and healthy individuals have failed to detect any efficacy of these approaches for the prevention of fracture and falls. Considering the well-recognized major musculoskeletal disorders associated with severe vitamin D deficiency and taking into account a possible biphasic effects of vitamin D on fracture and fall risks, an European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) working group convened, carefully reviewed, and analyzed the meta-analyses of randomized controlled trials on the effects of vitamin D on fracture risk, falls or osteoarthritis, and came to the conclusion that 1000 IU daily should be recommended in patients at increased risk of vitamin D deficiency. The group also addressed the identification of patients possibly benefitting from a vitamin D loading dose to achieve early 25-hydroxyvitamin D therapeutic level or from calcifediol administration.

Experience of a systematic approach to care and prevention of fragility fractures in New Zealand.

This narrative review describes efforts to improve the care and prevention of fragility fractures in New Zealand from 2012 to 2022. This includes development of clinical standards and registries to benchmark provision of care, and public awareness campaigns to promote a life-course approach to bone health. PURPOSE: This review describes the development and implementation of a systematic approach to care and prevention for New Zealanders with fragility fractures, and those at high risk of first fracture. Progression of existing initiatives and introduction of new initiatives are proposed for the period 2022 to 2030. METHODS: In 2012, Osteoporosis New Zealand developed and published a strategy with objectives relating to people who sustain hip and other fragility fractures, those at high risk of first fragility fracture or falls and all older people. The strategy also advocated formation of a national fragility fracture alliance to expedite change. RESULTS: In 2017, a previously informal national alliance was formalised under the Live Stronger for Longer programme, which includes stakeholder organisations from relevant sectors, including government, healthcare professionals, charities and the health system. Outputs of this alliance include development of Australian and New Zealand clinical guidelines, clinical standards and quality indicators and a bi-national registry that underpins efforts to improve hip fracture care. All 22 hospitals in New Zealand that operate on hip fracture patients currently submit data to the registry. An analogous approach is ongoing to improve secondary fracture prevention for people who sustain fragility fractures at other sites through nationwide access to Fracture Liaison Services. CONCLUSION: Widespread participation in national registries is enabling benchmarking against clinical standards as a means to improve the care of hip and other fragility fractures in New Zealand. An ongoing quality improvement programme is focused on eliminating unwarranted variation in delivery of secondary fracture prevention.

Quality improvement initiatives in the care and prevention of fragility fractures in the Asia Pacific region.

This narrative review summarises ongoing challenges and progress in the care and prevention of fragility fractures across the Asia Pacific region since mid-2019. The approaches taken could inform development of national bone health improvement Road Maps to be implemented at scale during the United Nations 'Decade of Healthy Ageing'. PURPOSE: This narrative review summarises recent studies that characterise the burden of fragility fractures, current care gaps and quality improvement initiatives intended to improve the care and prevention of fragility fractures across the Asia Pacific region. METHODS: The review focuses on published studies, reports and quality improvement initiatives undertaken during the period July 2019 to May 2022. RESULTS: Epidemiological studies conducted in countries and regions throughout Asia Pacific highlight the current and projected increasing burden of fragility fractures. Recent studies and reports document a persistent and pervasive post-fracture care gap among people who have sustained fragility fractures. Global initiatives developed by the Fragility Fracture Network and International Osteoporosis Foundation have gained significant momentum in the Asia Pacific region, despite the disruption caused by the COVID-pandemic. The Asia Pacific Fragility Fracture Alliance has developed educational resources including a Hip Fracture Registry Toolbox and a Primary Care Physician Education Toolkit. The Asia Pacific Osteoporosis and Fragility Fractures Society-a new section of the Asia Pacific Orthopaedic Association-is working to engage orthopaedic surgeons across the region in the care and prevention of fragility fractures. The Asia Pacific Consortium on Osteoporosis developed a framework to support national clinical guidelines development groups. Considerable activity at the national level is evident in many countries across the region. CONCLUSION: Development and implementation of national Road Maps informed by the findings of this review are urgently required to respond to the epidemiological emergency posed by fragility fractures during the United Nations 'Decade of Healthy Ageing'.

Management of patients at very high risk of osteoporotic fractures through sequential treatments.

Osteoporosis care has evolved markedly over the last 50 years, such that there are now an established clinical definition, validated methods of fracture risk assessment and a range of effective pharmacological agents. Currently, bone-forming (anabolic) agents, in many countries, are used in those patients who have continued to lose bone mineral density (BMD), patients with multiple subsequent fractures or those who have fractured despite treatment with antiresorptive agents. However, head-to-head data suggest that anabolic agents have greater rapidity and efficacy for fracture risk reduction than do antiresorptive therapies. The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) convened an expert working group to discuss the tools available to identify patients at high risk of fracture, review the evidence for the use of anabolic agents as the initial intervention in patients at highest risk of fracture and consider the sequence of therapy following their use. This position paper sets out the findings of the group and the consequent recommendations. The key conclusion is that the current evidence base supports an "anabolic first" approach in patients found to be at very high risk of fracture, followed by maintenance therapy using an antiresorptive agent, and with the subsequent need for antiosteoporosis therapy addressed over a lifetime horizon.

Fragility fractures in Europe: burden, management and opportunities.

This report provides an overview and a comparison of the burden and management of fragility fractures in the largest five countries of the European Union plus Sweden (EU6). In 2017, new fragility fractures in the EU6 are estimated at 2.7 million with an associated annual cost of €37.5 billion and a loss of 1.0 million quality-adjusted life years. INTRODUCTION: Osteoporosis is characterized by reduced bone mass and strength, which increases the risk of fragility fractures, which in turn, represent the main consequence of the disease. This report provides an overview and a comparison of the burden and management of fragility fractures in the largest five EU countries and Sweden (designated the EU6). METHODS: A series of metrics describing the burden and management of fragility fractures were defined by a scientific steering committee. A working group performed the data collection and analysis. Data were collected from current literature, available retrospective data and public sources. Different methods were applied (e.g. standard statistics and health economic modelling), where appropriate, to perform the analysis for each metric. RESULTS: Total fragility fractures in the EU6 are estimated to increase from 2.7 million in 2017 to 3.3 million in 2030; a 23% increase. The resulting annual fracture-related costs (€37.5 billion in 2017) are expected to increase by 27%. An estimated 1.0 million quality-adjusted life years (QALYs) were lost in 2017 due to fragility fractures. The current disability-adjusted life years (DALYs) per 1000 individuals age 50 years or more were estimated at 21 years, which is higher than the estimates for stroke or chronic obstructive pulmonary disease. The treatment gap (percentage of eligible individuals not receiving treatment with osteoporosis drugs) in the EU6 is estimated to be 73% for women and 63% for men; an increase of 17% since 2010. If all patients who fracture in the EU6 were enrolled into fracture liaison services, at least 19,000 fractures every year might be avoided. CONCLUSIONS: Fracture-related burden is expected to increase over the coming decades. Given the substantial treatment gap and proven cost-effectiveness of fracture prevention schemes such as fracture liaison services, urgent action is needed to ensure that all individuals at high risk of fragility fracture are appropriately assessed and treated.

Secondary Fracture Prevention: Consensus Clinical Recommendations from a Multistakeholder Coalition.

Osteoporosis-related fractures are undertreated, due in part to misinformation about recommended approaches to patient care and discrepancies among treatment guidelines. To help bridge this gap and improve patient outcomes, the American Society for Bone and Mineral Research assembled a multistakeholder coalition to develop clinical recommendations for the optimal prevention of secondary fractureamong people aged 65 years and older with a hip or vertebral fracture. The coalition developed 13 recommendations (7 primary and 6 secondary) strongly supported by the empirical literature. The coalition recommends increased communication with patients regarding fracture risk, mortality and morbidity outcomes, and fracture risk reduction. Risk assessment (including fall history) should occur at regular intervals with referral to physical and/or occupational therapy as appropriate. Oral, intravenous, andsubcutaneous pharmacotherapies are efficaciousandcanreduce risk of future fracture.Patientsneededucation,however, about thebenefitsandrisks of both treatment and not receiving treatment. Oral bisphosphonates alendronate and risedronate are first-line options and are generally well tolerated; otherwise, intravenous zoledronic acid and subcutaneous denosumab can be considered. Anabolic agents are expensive butmay be beneficial for selected patients at high risk.Optimal duration of pharmacotherapy is unknown but because the risk for second fractures is highest in the earlypost-fractureperiod,prompt treatment is recommended.Adequate dietary or supplemental vitaminDand calciumintake shouldbe assured. Individuals beingtreatedfor osteoporosis shouldbe reevaluated for fracture risk routinely, includingvia patienteducationabout osteoporosisandfracturesandmonitoringfor adverse treatment effects.Patients shouldbestronglyencouraged to avoid tobacco, consume alcohol inmoderation atmost, and engage in regular exercise and fall prevention strategies. Finally, referral to endocrinologists or other osteoporosis specialists may be warranted for individuals who experience repeated fracture or bone loss and those with complicating comorbidities (eg, hyperparathyroidism, chronic kidney disease).

Secondary Fracture Prevention: Consensus Clinical Recommendations from a Multistakeholder Coalition.

Osteoporosis-related fractures are undertreated, due in part to misinformation about recommended approaches to patient care and discrepancies among treatment guidelines. To help bridge this gap and improve patient outcomes, the American Society for Bone and Mineral Research assembled a multistakeholder coalition to develop clinical recommendations for the optimal prevention of secondary fracture among people aged 65 years and older with a hip or vertebral fracture. The coalition developed 13 recommendations (7 primary and 6 secondary) strongly supported by the empirical literature. The coalition recommends increased communication with patients regarding fracture risk, mortality and morbidity outcomes, and fracture risk reduction. Risk assessment (including fall history) should occur at regular intervals with referral to physical and/or occupational therapy as appropriate. Oral, intravenous, and subcutaneous pharmacotherapies are efficacious and can reduce risk of future fracture. Patients need education, however, about the benefits and risks of both treatment and not receiving treatment. Oral bisphosphonates alendronate and risedronate are first-line options and are generally well tolerated; otherwise, intravenous zoledronic acid and subcutaneous denosumab can be considered. Anabolic agents are expensive but may be beneficial for selected patients at high risk. Optimal duration of pharmacotherapy is unknown but because the risk for second fractures is highest in the early post-fracture period, prompt treatment is recommended. Adequate dietary or supplemental vitamin D and calcium intake should be assured. Individuals being treated for osteoporosis should be reevaluated for fracture risk routinely, including via patient education about osteoporosis and fractures and monitoring for adverse treatment effects. Patients should be strongly encouraged to avoid tobacco, consume alcohol in moderation at most, and engage in regular exercise and fall prevention strategies. Finally, referral to endocrinologists or other osteoporosis specialists may be warranted for individuals who experience repeated fracture or bone loss and those with complicating comorbidities (eg, hyperparathyroidism, chronic kidney disease). © 2019 American Society for Bone and Mineral Research.

Quality Improvement Initiatives in Fragility Fracture Care and Prevention.

PURPOSE OF REVIEW: This review sought to describe quality improvement initiatives in fragility fracture care and prevention. RECENT FINDINGS: A major care gap persists throughout the world in the secondary prevention of fragility fractures. Systematic reviews have confirmed that the Fracture Liaison Service (FLS) model of care is associated with significant improvements in rates of bone mineral density testing, initiation of osteoporosis treatment and adherence with treatment for individuals who sustain fragility fractures. Further, these improvements in the processes of care resulted in significant reductions in refracture risk and lower post-fracture mortality. The primary challenge facing health systems now is to ensure that best practice is delivered effectively in the local healthcare setting. Publication of clinical standards for FLS at the organisational and patient level in combination with the establishment of national registries has provided a mechanism for FLS to benchmark and improve their performance. Major efforts are ongoing at the global, regional and national level to improve the acute care, rehabilitation and secondary prevention for individuals who sustain fragility fractures. Active participation in these initiatives has the potential to eliminate current care gaps in the coming decade.

Radiofrequency echographic multi-spectrometry for the in-vivo assessment of bone strength: state of the art-outcomes of an expert consensus meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO).

PURPOSE: The purpose of this paper was to review the available approaches for bone strength assessment, osteoporosis diagnosis and fracture risk prediction, and to provide insights into radiofrequency echographic multi spectrometry (REMS), a non-ionizing axial skeleton technique. METHODS: A working group convened by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis met to review the current image-based methods for bone strength assessment and fracture risk estimation, and to discuss the clinical perspectives of REMS. RESULTS: Areal bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) is the consolidated indicator for osteoporosis diagnosis and fracture risk assessment. A more reliable fracture risk estimation would actually require an improved assessment of bone strength, integrating also bone quality information. Several different approaches have been proposed, including additional DXA-based parameters, quantitative computed tomography, and quantitative ultrasound. Although each of them showed a somewhat improved clinical performance, none satisfied all the requirements for a widespread routine employment, which was typically hindered by unclear clinical usefulness, radiation doses, limited accessibility, or inapplicability to spine and hip, therefore leaving several clinical needs still unmet. REMS is a clinically available technology for osteoporosis diagnosis and fracture risk assessment through the estimation of BMD on the axial skeleton reference sites. Its automatic processing of unfiltered ultrasound signals provides accurate BMD values in view of fracture risk assessment. CONCLUSIONS: New approaches for improved bone strength and fracture risk estimations are needed for a better management of osteoporotic patients. In this context, REMS represents a valuable approach for osteoporosis diagnosis and fracture risk prediction.

Practical guidance for engaging patients in health research, treatment guidelines and regulatory processes: results of an expert group meeting organized by the World Health Organization (WHO) and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO).

There is increasing emphasis on patient-centred research to support the development, approval and reimbursement of health interventions that best meet patients' needs. However, there is currently little guidance on how meaningful patient engagement may be achieved. An expert working group, representing a wide range of stakeholders and disciplines, was convened by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the World Health Organization (WHO). Through a structured, collaborative process the group generated practical guidance to facilitate optimal patient engagement in clinical development and regulatory decisions. Patient engagement is a relational process. The principles outlined in this report were based on lessons learned through applied experience and on an extensive dialogue among the expert participants. This practice guidance forms a starting point from which tailoring of the approach to suit different chronic diseases may be undertaken.

[OPG/RANKL: role and therapeutic target in osteoporosis]. / OPG/RANKL: implication et cible thérapeutique dans l'ostéoporose.

Given the increasing risk of fractures with aging in western countries, there is a need for the development of safe and efficient anti-osteoporotic drugs for the prevention and treatment of osteoporosis. Recent studies have provided evidence for an essential role of RANKL (Receptor Activator of Nuclear Factor-kappa B Ligand) and its decoy receptor osteoprotegerin in the control of osteoclast differentiation and survival. Post-menopausal osteoporosis results from an imbalance between resorption and formation associated with decreased OPG/RANKL. Targeting the OPG/RANKL system may therefore have a beneficial impact in osteoporosis. Accordingly, the development of novel strategies targeting OPG/RANKL using anti-RANKL or therapeutic intervention proved to be efficient to reduce bone resorption and to prevent bone loss in postmenopausal osteoporosis. This opens the way for novel therapeutic strategies for correcting bone metabolism in various pathologic disorders characterized by increased bone remodelling and bone loss.

Strontium ranelate promotes osteoblastic differentiation and mineralization of murine bone marrow stromal cells: involvement of prostaglandins.

UNLABELLED: Strontium ranelate is a new anti-osteoporosis treatment. This study showed that strontium ranelate stimulated PGE(2) production and osteoblastic differentiation in murine marrow stromal cells, which was markedly reduced by inhibition of COX-2 activity or disruption of COX-2 gene expression. Hence, some anabolic effects of strontium ranelate may be mediated by the induction of COX-2 and PGE(2) production. INTRODUCTION: Strontium ranelate is an orally active drug that reduces vertebral and hip fracture risk by increasing bone formation and reducing bone resorption. Strontium ranelate effects on bone formation are the result of increased osteoblastic differentiation and activity, but the mechanisms governing these effects are unknown. Based on previous work, we hypothesized that strontium ranelate increases cyclooxygenase (COX)-2 expression and that, consequently, the prostaglandin E(2) (PGE(2)) produced could mediate some effects of strontium ranelate on osteoblasts. MATERIALS AND METHODS: Marrow stromal cells (MSCs) from COX-2 wildtype (WT) and knockout (KO) mice were cultured with and without low-dose dexamethasone. Osteoblastic differentiation was characterized by alkaline phosphatase (ALP) activity, real-time PCR for ALP and osteocalcin (OCN) mRNA expression, and alizarin red staining for mineralization. Medium PGE(2) was measured by radioimmunoassay or enzyme immunoassay. RESULTS AND CONCLUSIONS: In MSCs from COX-2 WT mice, strontium ranelate significantly increased ALP activity, ALP and OCN mRNA expression, and mineralization after 14 or 21 days of culture. A short treatment at the beginning of the culture (0-7 days) with strontium ranelate was as effective as continuous treatment. Strontium ranelate (1 and 3 mM Sr(+2)) dose-dependently increased PGE(2) production, with maximum PGE(2) production occurring during the first week of culture. NS-398, a selective COX-2 inhibitor, blocked the strontium ranelate stimulation of PGE(2) production and significantly inhibited the strontium ranelate stimulation of ALP activity. In MSCs from COX-2 KO mice, the strontium ranelate stimulation of ALP and OCN mRNA expression and mineralization were markedly reduced compared with COX-2 WT cultures. Similar effects of strontium ranelate on osteoblastic markers and on PGE(2) production were seen when MSCs were cultured with or without low-dose dexamethasone (10 nM). We conclude that PGE(2) produced by the strontium ranelate induction of COX-2 expression plays a role in strontium ranelate-induced osteoblastic differentiation in MSCs in vitro.