Ischaemic cardiac events and use of strontium ranelate in postmenopausal osteoporosis: a nested case-control study in the CPRD

Role of Calcitonin and Strontium Ranelate in Osteoporosis

Background

Both Strontium Ranelate (SR) and Calcitonin (CT) can be used to treat osteoporosis. Calcitonin was actually one of the very initial medicines used to treat osteoporosis, especially in postmenopausal cases. However, the fracture prevention effect of Calcitonin is only proven to be in vertebrae and that too with nasal route only. When comparing Calcitonin with other conventional medications in treating osteoporosis, Calcitonin has got no additional advantages. Strontium Ranelate has got double effect, i.e., less bone resorption and more bone formation. Therefore, it can lead to an increase in bone mass significantly. Strontium Ranelate has been proven to decrease the risk of non-vertebral fractures as well as vertebral fractures.

Conclusion

Both Calcitonin and Strontium Ranelate are used only as a second-line therapy for the treatment of osteoporosis and not as first-line therapy, mainly because of their safety concern and also because they do not provide any advantages compared to other therapy for the treatment of osteoporosis.

Increased hypertension risk for the elderly with high blood levels of strontium and lead

Hypertension has long been recognized as the global health burden. Heavy metal pollution may be one of the environmental risk factors of hypertension. However, the association remains unclear. We studied the levels of aluminum (Al), vanadium (V), manganese (Mn), arsenic (As), selenium (Se), strontium (Sr), barium (Ba), titanium (Ti), lead (Pb) and cobalt (Co) in whole blood, and the relationship between trace element exposure and hypertension in the elderly community-based Chinese population. A total of 1013 participants from the west of Anhui Province in China were consecutively enrolled in this study in 2016. The general sociodemographic characteristics, lifestyles, disease history and physical examination information were collected by face-to-face survey and physical examination. The levels of ten trace elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). Multivariable logistic regression model was used to assess the association of trace element exposure with the risk of hypertension. Results showed that the odds ratio of hypertension in the highest quartile was 1.811 (95% CI 1.175-2.790, P trend = 0.005) and 1.772 (95% CI 1.121-2.800, P trend = 0.022), respectively, after adjusting for potential confounders, as compared with the lowest quartile of blood Pb and Sr levels.

New Insights into the In Vitro Antioxidant Routes and Osteogenic Properties of Sr/Zn Phytate Compounds

Sr/Zn phytate compounds have been shown interest in biomaterial science, specifically in dental implantology, due to their antimicrobial effects against Streptococcus mutans and their capacity to form bioactive coatings. Phytic acid is a natural chelating compound that shows antioxidant and osteogenic properties that can play an important role in bone remodelling processes affected by oxidative stress environments, such as those produced during infections. The application of non-protein cell-signalling molecules that regulate both bone and ROS homeostasis is a promising strategy for the regeneration of bone tissues affected by oxidative stress processes. In this context, phytic acid (PA) emerged as an excellent option since its antioxidant and osteogenic properties can play an important role in bone remodelling processes. In this study, we explored the antioxidant and osteogenic properties of two metallic PA complexes bearing bioactive cations, i.e., Sr²⁺ (SrPhy) and Zn²⁺ (ZnPhy), highlighting the effect of the divalent cations anchored to phytate moieties and their capability to modulate the PA properties. The in vitro features of the complexes were analyzed and compared with those of their precursor PA. The ferrozine/FeCl₂ method indicated that SrPhy exhibited a more remarkable ferrous ion affinity than ZnPhy, while the antioxidant activity demonstrated by a DPPH assay showed that only ZnPhy reduced the content of free radicals. Likewise, the antioxidant potential was assessed with RAW264.7 cell cultures. An ROS assay indicated again that ZnPhy was the only one to reduce the ROS content (20%), whereas all phytate compounds inhibited lipid peroxidation following the decreasing order of PA > SrPhy > ZnPhy. The in vitro evaluation of the phytate's osteogenic ability was performed using hMSC cells. The results showed tailored properties related to the cation bound in each complex. ZnPhy overexpressed ALP activity at 3 and 14 days, and SrPhy significantly increased calcium deposition after 21 days. This study demonstrated that Sr/Zn phytates maintained the antioxidant and osteogenic properties of PA and can be used in bone regenerative therapies involving oxidative environments, such as infected implant coatings and periodontal tissues.

How Has Molecular Biology Enhanced Our Undertaking of axSpA and Its Management

PURPOSE

This review aims at investigating pathophysiological mechanisms in spondyloarthritis (SpA). Analysis of genetic factors, immunological pathways, and abnormalities of bone metabolism lay the foundations for a better understanding of development of the axial clinical manifestations in patients, allowing physician to choose the most appropriate therapeutic strategy in a more targeted manner.

RECENT FINDINGS

In addition to the contribution of MHC system, findings emerged about the role of non-HLA genes (as ERAP1 and 2, whose inhibition could represent a new therapeutic approach) and of epigenetic mechanisms that regulate the expression of genes involved in SpA pathogenesis. Increasing evidence of bone metabolism abnormalities secondary to the activation of immunological pathways suggests the development of various bone anomalies that are present in axSpA patients. SpA are a group of inflammatory diseases with a multifactorial origin, whose pathogenesis is linked to the genetic predisposition, the action of environmental risk factors, and the activation of immune response. It is now well known how bone metabolism leads to long-term structural damage via increased bone turnover, bone loss and osteoporosis, osteitis, erosions, osteosclerosis, and osteoproliferation. These effects can exist in the same patient over time or even simultaneously. Evidence suggests a cross relationship among innate immunity, autoimmunity, and bone remodeling in SpA, making treatment approach a challenge for rheumatologists. Specifically, treatment targets are consistently increasing as new drugs are upcoming. Both biological and targeted synthetic drugs are promising in terms of their efficacy and safety profile in patients affected by SpA.

Comparative risk of acute myocardial infarction for anti-osteoporosis drugs in primary care: a meta-analysis of propensity-matched cohort findings from the UK Clinical Practice Research Database and the Catalan SIDIAP Database

The aim of this study was to evaluate the risk of acute myocardial infarction in patients taking osteoporosis medication. Patients were taken from the SIDIAP or CPRD database and were matched using propensity scores. Patients with diabetes and chronic kidney disease taking SERMs were at an increased risk. The results favour the cardiovascular safety of alendronate as a first-line choice for osteoporosis treatment.

INTRODUCTION

This study aims to evaluate the comparative safety of anti-osteoporosis drugs based on the observed risk of acute myocardial infarction while on treatment in a primary care setting.

METHODS

This is a propensity-matched cohort study and meta-analysis. This study was conducted in two primary care record databases covering UK NHS (CPRD) and Catalan healthcare (SIDIAP) patients during 1995-2014 and 2006-2014, respectively. The outcome was acute myocardial infarction while on treatment. Users of alendronate (reference group) were compared to those of (1) other oral bisphosphonates (OBP), (2) strontium ranelate (SR), and (3) selective oestrogen receptor modulator (SERM), after matching on baseline characteristics (socio-demographics, fracture risk factors, comorbidities, and concomitant drug use) using propensity scores. Multiple imputation was used to handle missing data on confounders and competing risk modelling for the calculation of relative risk (sub-distribution hazard ratios (SHR)) according to therapy. Country-specific data were analysed individually and meta-analysed.

RESULTS

A 10% increased risk of acute myocardial infarction was found in users of other bisphosphonates as compared to alendronate users within CPRD. The meta-analysis of CPRD and SIDIAP results showed a 9% increased risk in users of other bisphosphonate as compared to alendronate users. Sensitivity analysis showed SERMS users with diabetes and chronic kidney disease were at an elevated risk.

CONCLUSIONS

This study provides additional data on the risk of acute myocardial infarction in patients receiving osteoporosis treatment. The results favour the cardiovascular safety of alendronate as a first-line choice for osteoporosis treatment.

The potential role of herbal extract Wedelolactone for treating particle-induced osteolysis: an in vivo study

Background

Osteolysis is one of the most prevalent clinical complications affecting people who undergo total joint replacement (TJR). Wedelolactone (WDL) is a coumestan compound derived from the Wedelia chinensis plant and has been demonstrated to exhibit anti-inflammatory properties. This study aimed to investigate the oral administration of WDL as a potential treatment for particle-induced osteolysis using a well-established mice calvarial disease model.

Methods

Thirty-two C57BL/6 J mice were randomized into four groups: Sham, vehicle, osteolysis group with oral WDL treatment for 4 weeks (WDL 4w), and osteolysis group treated for 8 weeks (WDL 8w). Micro-CT was used to quantitatively analyze the bone mineral density (BMD), bone volume/tissue volume (BV/TV) and trabecular bone thickness (Tb.Th). Osteoclast numbers were also measured from histological slides by two investigators who were blind to the treatment used.

Results

The results from micro-CT observation showed that BMD in the WDL 8w group improved significantly over the vehicle group (p < 0.05), but there was no significant difference between WDL 4w and 8w for BV/TV and Tb.Th. Osteoclast numbers in the WDL 4w group were also lower than the vehicle group (p < 0.05), but the difference between WDL 8w and 4w groups was not significant.

Conclusions

Particle-induced osteolysis is an inevitable long-term complication after TJR. The results of this animal study indicate that an oral administration of WDL can help reduce the severity of osteolysis without adverse effects.

Absence of medication-related jaw osteonecrosis after treatment with strontium ranelate in ovariectomized rats

This study aimed to evaluate the potential of strontium ranelate (SR) in medication-related jaw osteonecrosis (MRONJ) after tooth extraction in ovariectomized rats. Thirty ovariectomized rats were divided into three groups (n = 10): bisphophonate (BP) group (zoledronic acid; 0.4 mg/kg/week), SR group (625 mg/kg/day), and control group (saline solution). The lower first molars were extracted after 60 days of drug therapy. Drug administration was continued for another 30 days after tooth extraction. The mandibles were subjected to clinical, histological, radiographic, and microtomographic evaluations. Only the BP group showed clinical changes, characterized by the presence of 70% (n = 7) and 20% (n = 2) of ulcers and extraoral fistulas. Radiographic evaluation demonstrated bone sequestration only in the BP group (n = 7, 70%). Microtomographic analysis revealed increased bone porosity after ovariectomy, particularly in the the control group (p < 0.05). The BP group showed a higher bone surface density, bone volume, and trabecular number than SR and control groups, but with less trabecular separation (p < 0.05). All the animals in the BP group demonstrated histological osteonecrosis. There was no evidence of osteonecrosis in the control and SR groups, which was characterized by the absence of empty osteocyte gaps and associated with the gradual healing of the extraction area. Also, an increased number of blood vessels and a reduced number of osteoclasts were observed in the SR group (p < 0.05). Therefore, SR treatment increased angiogenesis and osteoclastogenesis in the healing socket and was not associated with MRONJ development after tooth extraction in ovariectomized rats.

Chondroprotective effect of melatonin and strontium ranelate in animal model of osteoarthritis

PURPOSE

To analyze the action of strontium ranelate (SR) and melatonin in isolation or in association in knees, liver and kidneys of rats Wistar with induced osteoarthritis (OA).

METHODS

Thirty male rats were induced to OA through an anterior cruciate ligament transection (ACLT), and treated with melatonin and SR in isolation or in association. Morphological, histopathological, histochemical and morphometric analysis were realized of the structure of the articular capsule, as well as histopathological analysis of liver and kidneys from the animals.

RESULTS

The experimental model was successful. The association of the drugs presented chondroprotective pharmacodynamics. However, more successful results were identified from analysis of animals in which received melatonin in isolation, regarding biochemical parameters of glutamic oxalacetic transaminase. The prepared slide samples of liver and kidneys from groups submitted to the isolated use of SR and melatonin or the association of these drugs presented no differences, when compared to the control group.

DISCUSSION

The administration of the drugs presented chondroprotective effect and prevented from the aggravation of articulate damages, and was not capable of modifying the histology of liver or kidneys. This finding suggests a safe association for the treatment of OA, however it requires further investigation in order to expand therapeutic perspectives regarding improvements of the quality of life of individuals in our society.

Cardiovascular safety of calcium, magnesium and strontium: what does the evidence say?

Calcium, magnesium and strontium have all been implicated in both musculoskeletal and cardiovascular health and disease. However, despite these three elements being closely chemically related, there is marked heterogeneity of their characteristics in relation to cardiovascular outcomes. In this narrative review, we describe the relevant evidential landscape, focusing on clinical trials where possible and incorporating findings from observational and causal analyses, to discern the relative roles of these elements in musculoskeletal and cardiovascular health. We conclude that calcium supplementation (for bone health) is most appropriately used in combination with vitamin D supplementation and targeted to those who are deficient in these nutrients, or in combination with antiosteoporosis medications. Whilst calcium supplementation is associated with gastrointestinal side effects and a small increased risk of renal stones, purported links with cardiovascular outcomes remain unconvincing. In normal physiology, no mechanism for an association has been elucidated and other considerations such as dose response and temporal relationships do not support a causal relationship. There is little evidence to support routine magnesium supplementation for musculoskeletal outcomes; greater dietary intake and serum concentrations appear protective against cardiovascular events. Strontium ranelate, which is now available again as a generic medication, has clear anti-fracture efficacy but is associated with an increased risk of thromboembolic disease. Whilst a signal for increased risk of myocardial infarction has been detected in some studies, this is not supported by wider analyses. Strontium ranelate, under its current licence, thus provides a useful therapeutic option for severe osteoporosis in those who do not have cardiovascular risk factors.

Comparative cardiovascular safety of strontium ranelate and bisphosphonates: a multi-database study in 5 EU countries by the EU-ADR Alliance

Strontium ranelate use, compared with oral bisphosphonates, is not associated with increased risk of AMI in patients with no contraindications for SR use. However, current strontium ranelate (compared with current bisphosphonate) appears associated with 25-30% excess risk of VTE and 35% excess risk of CVDeath.

INTRODUCTION

Evaluate the risk of cardiac and thromboembolic events among new users of SR and oral BPs without contraindications for SR.

METHODS

We conducted three multi-national, multi-database (Aarhus-Denmark, HSD-Italy, IPCI-Netherlands, SIDIAP-Spain, THIN-UK) case-control studies nested within a cohort of new users of SR/BP. We matched cases of acute myocardial infarction (AMI), venous thromboembolism (VTE), and cardiovascular death (CVDeath), up to 10 controls on gender, year of birth, index date, and country. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CIs) according to current SR vs current BP use and current vs past SR use, adjusting for potential confounders. Data were pooled using random effects meta-analysis.

RESULTS

No excess risk of AMI (5477 cases/54,674 controls) was found with current SR vs current BP (OR 0.89 (95%CI 0.70, 1.12)) nor with current vs past SR use (0.71(0.56, 0.91)). For VTE (5614 cases/6036 controls), an excess risk was found with current SR compared with current BP use, 1.24 (0.96, 1.61), and current vs past SR use, 1.30 (1.04, 1.62). For CVDeath (3019 cases/29,871 controls), an increased risk was seen with current SR vs current BP use, 1.35 (1.02, 1.80), but not with current vs past SR use (0.68 (0.48, 0.96)).

CONCLUSION

In patients without contraindications for SR, we found no evidence of an increased risk of AMI but a 25-30% excess risk of VTE and a 35% excess risk of CVDeath with current SR vs current BP users. This is despite a reduction in risk in CVDeath with current vs past SR users. The latter disparity could still be partially explained by cessation of preventative therapies in end-of-life or residual confounding by indication.

A review of the latest insights into the mechanism of action of strontium in bone

Interest in strontium (Sr) has persisted over the last three decades due to its unique mechanism of action: it simultaneously promotes osteoblast function and inhibits osteoclast function. While this mechanism of action is strongly supported by in vitro studies and small animal trials, recent large-scale clinical trials have demonstrated that orally administered strontium ranelate (SrRan) may have no anabolic effect on bone formation in humans. Yet, there is a strong correlation between Sr accumulation in bone and reduced fracture risk in post-menopausal women, suggesting Sr acts via a purely physiochemical mechanism to enhance bone strength. Conversely, the local administration of Sr with the use of modified biomaterials has been shown to enhance bone growth, osseointegration and bone healing at the bone-implant interface, to a greater degree than Sr-free materials. This review summarizes current knowledge of the main cellular and physiochemical mechanisms that underly Sr's effect in bone, which center around Sr's similarity to calcium (Ca). We will also summarize the main controversies in Sr research which cast doubt on the 'dual-acting mechanism'. Lastly, we will explore the effects of Sr-modified bone-implant materials both in vitro and in vivo, examining whether Sr may act via an alternate mechanism when administered locally.

Osteogenesis-Related Gene Expression and Guided Bone Regeneration of a Strontium-Doped Calcium-Phosphate-Coated Titanium Mesh

Guided bone regeneration using a perforated titanium membrane is actively used in oral and orthopedic surgeries to provide space for the subsequent filling of a new bone in the case of bone defects and to achieve proper bone augmentation and reconstruction. The surface modification of a titanium membrane using a strontium-substituted calcium phosphate coating has become a popular trend to provide better bioactivity and biocompatibility on the membrane for improving the bone regeneration because strontium can stimulate not only the differentiation of osteoblasts but also inhibit the differentiation of osteoclasts. The strontium-doped calcium phosphate coating on the titanium mesh was formed by the cyclic precalcification method, and its effects on bone regeneration were evaluated by in vitro analysis of osteogenesis-related gene expression and in vivo evaluation of osteogenesis of the titanium mesh using the rat calvarial defect model in this study. It was identified that the strontium-doped calcium phosphate-treated mesh showed a higher expression of all genes related to osteogenesis in the osteoblast cells and resulted in new bone formation with better osseointegration with the mesh in the rat calvarial defect, in comparison with the results of untreated and calcium phosphate-treated meshes.

Human mesenchymal stem cells differentiate into an osteogenic lineage in presence of strontium containing bioactive glass nanoparticles

While bioactive glass and ions released during its dissolution are known to stimulate osteoblast cells, the effect bioactive glass has on human stem cells is not clear. Here, we show that spherical monodispersed strontium containing bioactive nanoparticles (Sr-BGNPs) of composition 90.6 mol% SiO₂, 5.0 mol% CaO, 4.4% mol% SrO (4.4%Sr-BGNPs) and 88.8 mol% SiO₂, 1.8 mol% CaO, and 9.4 mol% SrO (9.4%Sr-BGNPs) stimulate bone marrow derived human stem cell (hMSC) differentiation down an osteogenic pathway without osteogenic supplements. The particles were synthesised using a modified Stӧber process and had diameters of 90 ± 10 nm. Previous work on similar particles that did not contain Sr (80 mol% SiO₂, 20 mol% CaO) showed stem cells did not differentiate when exposed to the particles. Here, both compositions of the Sr-BGNPs (up to concentration of 250 μg/mL) stimulated the early-, mid-, and late-stage markers of osteogenic differentiation and accelerated mineralisation in the absence of osteogenic supplements. Sr ions play a key role in osteogenic stem cell differentiation. Sr-BGNP dissolution products did not adversely affect hMSC viability and no significant differences in viability were measured between each particle composition. Confocal and transmission electron microscopy (TEM) demonstrated that monodispersed Sr-BGNPs were internalised and localised within vesicles in the cytoplasm of hMSCs. Degradation of particles inside the cells was observed, whilst maintaining effective cations (Ca and Sr) in their silica network after 24 h in culture. The uptake of Sr-BGNPs by hMSCs was reduced by inhibitors of specific routes of endocytosis, indicating that the Sr-BGNPs uptake by hMSCs was probably via mixed endocytosis mechanisms. Sr-BGNPs have potential as injectable therapeutic devices for bone regeneration or treatment of conditions such as osteoporosis, because of their ability deliver a sustained release of osteogenic inorganic cations, e.g. calcium (Ca) or and strontium (Sr), through particle degradation locally to cells. STATEMENT OF SIGNIFICANCE: Here, we show that 90 nm spherical strontium containing bioactive nanoparticles of stimulate bone marrow derived human stem cell (hMSC) differentiation down an osteogenic pathway without the use of osteogenic supplements. While bioactive glass and its dissolution products are known to promote excellent bone regeneration in vivo and to stimulate osteoblast cells to produce bone matrix in vitro, their effect on human stem cells is not clear. Previously our nanoparticles that contained only SiO₂ and CaO did not provoke human bone marrow or adipose derived stem cell differentiation.

Osteogenic, anti-osteoclastogenic and immunomodulatory properties of a strontium-releasing hybrid scaffold for bone repair

Strontium (Sr) is known to stimulate osteogenesis, while inhibiting osteoclastogenesis, thus encouraging research on its application as a therapeutic agent for bone repair/regeneration. It has been suggested that it may possess immunomodulatory properties, which might act synergistically in bone repair/regeneration processes. To further explore this hypothesis we have designed a Sr-hybrid system composed of an in situ forming Sr-crosslinked RGD-alginate hydrogel reinforced with Sr-doped hydroxyapatite (HAp) microspheres and studied its in vitro osteoinductive behaviour and in vivo inflammatory response. The Sr-hybrid scaffold acts as a dual Sr²⁺ delivery system, showing a cumulative Sr²⁺ release of ca. 0.3 mM after 15 days. In vitro studies using Sr²⁺concentrations within this range (0 to 3 mM Sr²⁺) confirmed its ability to induce osteogenic differentiation of mesenchymal stem/stromal cells (MSC), as well as to reduce osteoclastogenesis and osteoclasts (OC) functionality. In comparison with a similar Sr-free system, the Sr-hybrid system stimulated osteogenic differentiation of MSC, while inhibiting the formation of OC. Implantation in an in vivo model of inflammation, revealed an increase in F4/80⁺/CD206⁺ cells, highlighting its ability to modulate the inflammatory response as a pro-resolution mediator, through M2 macrophage polarization. Therefore, the Sr-hybrid system is potentially an appealing biomaterial for future clinical applications.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY CLINICAL PRACTICE GUIDELINES FOR THE DIAGNOSIS AND TREATMENT OF POSTMENOPAUSAL OSTEOPOROSIS - 2016

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists AFF = atypical femur fracture ASBMR = American Society for Bone and Mineral Research BEL = best evidence level BMD = bone mineral density BTM = bone turnover marker CBC = complete blood count CI = confidence interval DXA = dual-energy X-ray absorptiometry EL = evidence level FDA = U.S. Food and Drug Administration FLEX = Fracture Intervention Trial (FIT) Long-term Extension FRAX_® = Fracture Risk Assessment Tool GFR = glomerular filtration rate GI = gastrointestinal HORIZON = Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly IOF = International Osteoporosis Foundation ISCD = International Society for Clinical Densitometry IU = international units IV = intravenous LSC = least significant change NBHA = National Bone Health Alliance NOF = National Osteoporosis Foundation 25(OH)D = 25-hydroxy vitamin D ONJ = osteonecrosis of the jaw PINP = serum carboxy-terminal propeptide of type I collagen PTH = parathyroid hormone R = recommendation RANK = receptor activator of nuclear factor kappa-B RANKL = receptor activator of nuclear factor kappa-B ligand RCT = randomized controlled trial RR = relative risk S-CTX = serum C-terminal telopeptide SQ = subcutaneous VFA = vertebral fracture assessment WHO = World Health Organization.

Impacts of Psychological Stress on Osteoporosis: Clinical Implications and Treatment Interactions

The significant biochemical and physiological effects of psychological stress are beginning to be recognized as exacerbating common diseases, including osteoporosis. This review discusses the current evidence for psychological stress-associated mental health disorders as risk factors for osteoporosis, the mechanisms that may link these conditions, and potential implications for treatment. Traditional, alternative, and adjunctive therapies are discussed. This review is not intended to provide therapeutic recommendations, but, rather, the goal of this review is to delineate potential interactions of psychological stress and osteoporosis and to highlight potential multi-system implications of pharmacological interventions. Review of the current literature identifies several potentially overlapping mechanistic pathways that may be of interest (e.g., glucocorticoid signaling, insulin-like growth factor signaling, serotonin signaling) for further basic and clinical research. Current literature also supports the potential for cross-effects of therapeutics for osteoporosis and mental health disorders. While studies examining a direct link between osteoporosis and chronic psychological stress are limited, the studies reviewed herein suggest that a multi-factorial, personalized approach should be considered for improved patient outcomes in populations experiencing psychological stress, particularly those at high-risk for development of osteoporosis.

Association of Alendronate and Risk of Cardiovascular Events in Patients With Hip Fracture

The risk of cardiovascular events (CVEs) with alendronate use in real-world hip fracture patients is unknown. This study aimed to investigate the risk of CVE with and without use of alendronate in patients with hip fracture. We conducted a retrospective cohort study using a population-wide database managed by the Hong Kong Hospital Authority. Patients newly diagnosed with hip fracture from 2005 through 2013 were followed until November 6, 2016. Alendronate and other antiosteoporosis medications use during the study period were examined. We matched treated and nontreated patients based on time-dependent propensity score. The risks of cardiovascular mortality, myocardial infarction, and stroke between treatment groups were evaluated using conditional Cox regression stratified by match pairs. To examine the associations over time, outcomes were assessed at 1 year, 3 years, 5 years, and 10 years. Among 34,991 patients with newly diagnosed hip fracture, 4602 (13.2%) received antiosteoporosis treatment during follow-up. Physical functioning or survival prospect was not significantly different between treated and nontreated patients. A total of 4594 treated patients were matched with 13,568 nontreated patients. Results of Cox regression analysis revealed that alendronate was associated with a significantly lower risk of 1-year cardiovascular mortality (HR 0.33; 95% CI, 0.17 to 0.65) and incident myocardial infarction (HR 0.55; 95% CI, 0.34 to 0.89), whereas marginally significant reduction in risk of stroke was observed at 5 years and 10 years (HR at 5 years: 0.82; 95% CI, 0.67 to 1.00; p = 0.049; HR at 10 years: 0.83; 95% CI, 0.69 to 1.01; p = 0.065). The strength of the association declined over time but remained significant. Similar results were observed when all nitrogen-containing bisphosphonates (N-BPs) were analyzed together. These findings were robust in multiple sensitivity analyses. Additional studies in other population samples and randomized clinical trials may be warranted to further understand the relationship between use of various antiosteoporosis medication and risk of CVE in patients with hip fracture. © 2018 American Society for Bone and Mineral Research.

Strontium ranelate as a possible disease-modifying osteoarthritis drug: a systematic review

Considering that osteoarthritis (OA) is the most prevalent joint disease worldwide, multiple pharmacological treatments have been proposed to alter the articular structure with potential benefit in the progression of the disease. The so-called disease-modifying OA drugs have been frequently investigated but conclusive findings are rare. Strontium ranelate (SrRan) is a drug usually prescribed to treat osteoporosis, with proven effects in decreasing the risk of fractures and possible effect in reducing the progression of OA. The objective of this review was to demonstrate the current panorama of knowledge on the use of SrRan in clinical and experimental models, clarifying its mechanisms of action and describing possible anti-nociceptive and anti-inflammatory effects. The systematic review was based on the PRISMA statement and included articles that are indexed in scientific databases. Fifteen studies were included: seven pre-clinical and eight clinical studies. Despite the limited number of studies, the results suggest a positive effect of SrRan in patients with OA, through changes in functional capacity and reduction of progression of morphological parameters and joint degradation, with moderate quality of evidence for those clinical outcomes. Novel studies are necessary to elucidate the molecular targets of SrRan, focusing on anti-inflammatory effects and histological changes promoted by SrRan, which seemed to reduce the progression of OA in the experimental and clinical studies.

Strontium and its role in preeclampsia

BACKGROUND

Preeclampsia (PE) is considered a specific vascular disease in which endothelial dysfunction may be the crucial factor of its pathogenesis. It has been suggested that strontium (Sr) may play a role in the pathophysiology of PE. Our group established in a previous study the serum levels of Sr in healthy pregnancies, and the main aim of the present study was to evaluate Sr concentrations and oxidative status in preeclamptic women.

METHODS

The study population included women with early-onset PE (E-PE, n = 39), late-onset PE (L-PE, n = 67) and serial samples from a subset of preeclamptic women (PE-ss, n = 20). The control group included women with gestational hypertension (GH, n = 56) and healthy pregnancies (samples collected in the 1st (n = 50), 2nd (n = 51) and 3rd trimesters (n = 53)). Strontium, calcium (Ca), uric acid (UA), placental growth factor (PlGF), soluble fms-like tyrosine kinase 1 (sFlt-1), N-terminal pro-brain natriuretic peptide (NT-proBNP), lipid peroxidation and total antioxidant activity (TAA) were measured in these samples.

RESULTS

Mean Sr levels were significantly higher in PE than in control groups (p ≤ 0.0001). Calcium values were found to be significantly lower in E-PE compared to control groups (p = 0.03). Higher levels of NT-proBNP were found in PE vs. control groups (p < 0.001). sFlt-1/PlGF ratio was higher in E-PE compared to L-PE and GH (p < 0.001). Uric acid levels in PE were significantly higher than in control groups (p < 0.0001). There was a strong positive correlation between UA and Sr in the E-PE serial samples (r = 0.80, p < 0.0001). Lipid peroxidation and lipid peroxidation/TAA ratios were found to be higher in PE, with lower values of TAA.

CONCLUSION

The higher levels of Sr and the alterations of redox status found in preeclamptic women, along with the strong correlation between UA and Sr suggest that this element may be involved in the pathogenesis of PE.

G protein-coupled receptors as anabolic drug targets in osteoporosis

Osteoporosis is a progressive bone disorder characterised by imbalance between bone building (anabolism) and resorption (catabolism). Most therapeutics target inhibition of osteoclast-mediated bone resorption, but more recent attention in early drug discovery has focussed on anabolic targets in osteoblasts or their precursors. Two marketed agents that display anabolic properties, strontium ranelate and teriparatide, mediate their actions via the G protein-coupled calcium-sensing and parathyroid hormone-1 receptors, respectively. This review explores their activity, the potential for improved therapeutics targeting these receptors and other putative anabolic GPCR targets, including Smoothened, Wnt/Frizzled, relaxin family peptide, adenosine, cannabinoid, prostaglandin and sphingosine-1-phosphate receptors.

Advanced glycation end products and strontium ranelate promote osteogenic differentiation of vascular smooth muscle cells in vitro: Preventive role of vitamin D

Advanced glycation end products (AGE) have been demonstrated to induce the osteogenic trans-differentiation of vascular smooth muscle cells (VSMC). Strontium ranelate (SR) is an anti-osteoporotic agent that has both anti-catabolic and anabolic actions on bone tissue. However, in the last years SR has been associated with an increase of cardiovascular risk. We hypothesize that SR can increase the osteoblastic trans-differentiation of VSMC and the induction of extracellular calcifications, an effect that could be potentiated in the presence of AGE and inhibited by simultaneous administration of vitamin D. The present results of our in vitro experiments demonstrate that AGE and SR alone or in combination, stimulate L-type calcium channels, causing an increase in reactive oxygen species and activation of both ERK and NFkB, with the final effect of promoting the osteogenic shift of VSMC. Importantly, these in vitro effects of AGE and/or SR can be prevented by co-incubation with vitamin D.

Injectable hybrid system for strontium local delivery promotes bone regeneration in a rat critical-sized defect model

Strontium (Sr) has been described as having beneficial influence in bone strength and architecture. However, negative systemic effects have been reported on oral administration of Sr ranelate, leading to strict restrictions in clinical application. We hypothesized that local delivery of Sr improves osteogenesis without eliciting detrimental side effects. Therefore, the in vivo response to an injectable Sr-hybrid system composed of RGD-alginate hydrogel cross-linked in situ with Sr and reinforced with Sr-doped hydroxyapatite microspheres, was investigated. The system was injected in a critical-sized bone defect model and compared to a similar Sr-free material. Micro-CT results show a trend towards higher new bone formed in Sr-hybrid group and major histological differences were observed between groups. Higher cell invasion was detected at the center of the defect of Sr-hybrid group after 15 days with earlier bone formation. Higher material degradation with increase of collagen fibers and bone formation in the center of the defect after 60 days was observed as opposed to bone formation restricted to the periphery of the defect in the control. These histological findings support the evidence of an improved response with the Sr enriched material. Importantly, no alterations were observed in the Sr levels in systemic organs or serum.

In vivo and clinical application of strontium-enriched biomaterials for bone regeneration: A systematic review

OBJECTIVES

This systematic review aimed to assess the in vivo and clinical effect of strontium (Sr)-enriched biomaterials in bone formation and/or remodelling.

METHODS

A systematic search was performed in Pubmed, followed by a two-step selection process. We included in vivo original studies on Sr-containing biomaterials used for bone support or regeneration, comparing at least two groups that only differ in Sr addition in the experimental group.

RESULTS

A total of 572 references were retrieved and 27 were included. Animal models were used in 26 articles, and one article described a human study. Osteoporotic models were included in 11 papers. All articles showed similar or increased effect of Sr in bone formation and/or regeneration, in both healthy and osteoporotic models. No study found a decreased effect. Adverse effects were assessed in 17 articles, 13 on local and four on systemic adverse effects. From these, only one reported a systemic impact from Sr addition. Data on gene and/or protein expression were available from seven studies.

CONCLUSIONS

This review showed the safety and effectiveness of Sr-enriched biomaterials for stimulating bone formation and remodelling in animal models. The effect seems to increase over time and is impacted by the concentration used. However, included studies present a wide range of study methods. Future work should focus on consistent models and guidelines when developing a future clinical application of this element.Cite this article: N. Neves, D. Linhares, G. Costa, C. C. Ribeiro, M. A. Barbosa. In vivo and clinical application of strontium-enriched biomaterials for bone regeneration: A systematic review. Bone Joint Res 2017;6:366-375. DOI: 10.1302/2046-3758.66.BJR-2016-0311.R1.

Efficacy of Osteoporosis Therapies in Diabetic Patients

Diabetes is characterized by increased fracture risk and by reduced bone strength for a given density. Contributing factors may include lower bone turnover and accumulation of advanced glycation endproducts. There are concerns that the pharmacological therapies for osteoporosis, particularly anti-resorptive therapies that suppress bone turnover, may not be as effective in the setting of diabetes. This review considers clinical trials and observational studies that have assessed the efficacy of anti-resorptive and anabolic therapies in diabetic patients. Post hoc analyses of randomized trials indicate that raloxifene has similar efficacy for prevention of vertebral fractures in diabetic compared with non-diabetic patients. Evidence from randomized clinical trials is lacking for anti-fracture efficacy of other osteoporosis therapies in diabetes. However, observational studies suggest that bisphosphonates are effective in preventing fractures in diabetic patients. The great majority of diabetic patients in studies to date have been type 2, and efficacy of osteoporosis therapies in type 1 diabetic patients remains to be addressed. Further evaluation of the efficacy of osteoporosis therapies in the setting of diabetes is needed to provide optimal fracture prevention for this population.

Italian association of clinical endocrinologists (AME) position statement: drug therapy of osteoporosis

Treatment of osteoporosis is aimed to prevent fragility fractures and to stabilize or increase bone mineral density. Several drugs with different efficacy and safety profiles are available. The long-term therapeutic strategy should be planned, and the initial treatment should be selected according to the individual site-specific fracture risk and the need to give the maximal protection when the fracture risk is highest (i.e. in the late life). The present consensus focused on the strategies for the treatment of postmenopausal osteoporosis taking into consideration all the drugs available for this purpose. A short revision of the literature about treatment of secondary osteoporosis due both to androgen deprivation therapy for prostate cancer and to aromatase inhibitors for breast cancer was also performed. Also premenopausal females and males with osteoporosis are frequently seen in endocrine settings. Finally particular attention was paid to the tailoring of treatment as well as to its duration.

Managing Osteoporosis in Patients on Long-Term Bisphosphonate Treatment: Report of a Task Force of the American Society for Bone and Mineral Research

Bisphosphonates (BPs) are the most commonly used medications for osteoporosis. This ASBMR report provides guidance on BP therapy duration with a risk-benefit perspective. Two trials provided evidence for long-term BP use. In the Fracture Intervention Trial Long-term Extension (FLEX), postmenopausal women receiving alendronate for 10 years had fewer clinical vertebral fractures than those switched to placebo after 5 years. In the HORIZON extension, women who received 6 annual infusions of zoledronic acid had fewer morphometric vertebral fractures compared with those switched to placebo after 3 years. Low hip T-score, between -2 and -2.5 in FLEX and below -2.5 in HORIZON extension, predicted a beneficial response to continued therapy. Hence, the Task Force suggests that after 5 years of oral BP or 3 years of intravenous BP, reassessment of risk should be considered. In women at high risk, for example, older women, those with a low hip T-score or high fracture risk score, those with previous major osteoporotic fracture, or who fracture on therapy, continuation of treatment for up to 10 years (oral) or 6 years (intravenous), with periodic evaluation, should be considered. The risk of atypical femoral fracture, but not osteonecrosis of the jaw, clearly increases with BP therapy duration, but such rare events are outweighed by vertebral fracture risk reduction in high-risk patients. For women not at high fracture risk after 3 to 5 years of BP treatment, a drug holiday of 2 to 3 years can be considered. The suggested approach for long-term BP use is based on limited evidence, only for vertebral fracture reduction, in mostly white postmenopausal women, and does not replace the need for clinical judgment. It may be applicable to men and patients with glucocorticoid-induced osteoporosis, with some adaptations. It is unlikely that future trials will provide data for formulating definitive recommendations. © 2015 American Society for Bone and Mineral Research.

History of cardiovascular events and cardiovascular risk factors among patients initiating strontium ranelate for treatment of osteoporosis

PURPOSE

To estimate the proportion of osteoporosis patients in whom initiating strontium ranelate treatment, under new EMA guidelines, should be contraindicated because of a history of cardiovascular events or risk for cardiovascular events.

MATERIALS AND METHODS

This was a retrospective analysis of medical and pharmacy claims using the Clinical Practice Research Datalink database. Patients were included if they had ≥1 prescription of strontium from September 1, 2008 to August 31, 2013, were aged ≥50 as of the index date (the date of the first ever strontium ranelate prescription), and had ≥1 year of medical records pre-index. Cardiovascular events occurring any time pre-index were identified, which included ischemic heart disease, cerebrovascular disease, uncontrolled hypertension, and peripheral arterial disease. Cardiovascular risk factors assessed included 1) diabetes or hypertension any time pre-index; 2) hyperlipidemia in the 12 months pre-index; or 3) obesity in the 12 months pre-index.

RESULTS

A total of 7,474 patients were included: 90.4% were women, with an average age of 76.5 years, and 84.5% used osteoporosis therapy, either bisphosphonates or non-bisphosphonates, prior to strontium initiation. A total of 23.6% of patients experienced ≥1 cardiovascular event prior to strontium initiation; the rate was lower among female patients than in male patients (22.4% vs 35.3%, P<0.01). A total of 45.9% had risk factors for cardiovascular events (without cardiovascular event history).

CONCLUSION

More than one-fifth of osteoporosis patients in the UK who used strontium had a cardiovascular event history, and one-half had cardiovascular risk factors prior to strontium initiation.

The position of strontium ranelate in today's management of osteoporosis

Osteoporosis accounts for about 3 % of total European health-care spending. The low proportion of costs for the pharmacological prevention of osteoporotic fracture means that it is highly cost saving, especially in patient with severe osteoporosis or patients who cannot take certain osteoporosis medications due to issues of contraindications or tolerability. Following recent regulatory changes, strontium ranelate is now indicated in patients with severe osteoporosis for whom treatment with other osteoporosis treatments is not possible, and without contraindications including uncontrolled hypertension, established, current or past history of ischaemic heart disease, peripheral arterial disease, and/or cerebrovascular disease. We review here today's evidence for the safety and efficacy of strontium ranelate. The efficacy of strontium ranelate in patients complying with the new prescribing information (i.e. severe osteoporosis without contraindications) has been explored in a multivariate analysis of clinical trial data, which concluded that the antifracture efficacy of strontium ranelate is maintained in patients with severe osteoporosis without contraindications and also demonstrated how the new target population mitigates risk. Strontium ranelate is therefore an important alternative in today's management of osteoporosis, with a positive benefit-risk balance, provided that the revised indication and contraindications are followed and cardiovascular risk is monitored. The bone community should be reassured that there remain viable alternatives in patients in whom treatment with other agents is not possible and protection against the debilitating effects of fracture is still feasible in patients with severe osteoporosis.

Treatment of primary osteoporosis in men

With the aging of the population worldwide, osteoporosis and osteoporotic fractures are becoming a serious health care issue in the Western world. Although less frequent than in women, osteoporosis in men is a relatively common problem. Hip and vertebral fractures are particularly relevant, being associated with significant mortality and disability. Since bone loss and fragility fractures in men have been recognized as serious medical conditions, several randomized controlled trials (RCTs) have been undertaken in males with osteoporosis to investigate the anti-fracture efficacy of the pharmacological agents commonly used to treat postmenopausal osteoporosis. Overall, treatments for osteoporosis in men are less defined than in women, mainly due to the fact that there are fewer RCTs performed in male populations, to the relatively smaller sample sizes, and to the lack of long-term extension studies. However, the key question is whether men are expected to respond differently to osteoporosis therapies than women. The pharmacological properties of bisphosphonates, teriparatide, denosumab, and strontium ranelate make such differentiation unlikely, and available clinical data support their efficacy in men with primary osteoporosis as well as in women. In a series of well-designed RCTs, alendronate, risedronate, zoledronic acid, and teriparatide were demonstrated to reduce the risk of new vertebral fractures in men presenting with primary osteoporosis (including osteoporosis associated with low testosterone levels) and to improve the bone mineral density (BMD). In preliminary studies, ibandronate, denosumab, and strontium ranelate also showed their beneficial effects on surrogate outcomes (BMD and markers of bone turnover) in men with osteoporosis. Although direct evidence about their non-vertebral anti-fracture efficacy are lacking, the effects of bisphosphonates, denosumab, teriparatide, and strontium ranelate on surrogate outcomes (BMD and markers of bone turnover) were similar to those reported in pivotal RCTs undertaken in postmenopausal women, in which vertebral and non-vertebral anti-fracture efficacy have been clearly demonstrated. In conclusion, sufficient data exist to support the use of these pharmacological agents in men with primary osteoporosis. Further RCTs are warranted to establish their long-term efficacy and safety.

Established and forthcoming drugs for the treatment of osteoporosis

PURPOSE OF REVIEW

The aim of treatment in patients at high risk for fractures is to reduce the risk of a first or a subsequent fracture. New data are available on the antifracture effects and side-effects of antiresorptive and osteoanabolic drugs, and new emerging therapies with new modes of action are on the horizon.

RECENT FINDINGS

Calcium and vitamin D intake should be sufficient, but not too high. Vertebral, nonvertebral (including hip fracture) prevention with antiresorptive drugs such as bisphosphonates (alendronate, risedronate and zoledronic acid) and denosumab exceeds the risk of rare side-effects such as atypical femur fracture and osteonecrosis of the jaw. Teriparatide is an osteoanabolic drug that improves quality of life in severe osteoporosis. Strontium ranelate decreases dynamic parameters of bone formation during the first year of treatment, and could increase the risk of cardiovascular events in high-risk patients. Initiation of and adherence to fracture prevention drugs are still low. New potential developments in antiresorptive drugs include odanacatib, a selective inhibitor of cathepsin K, and, in osteoanabolic drugs, monoclonal antibodies against sclerostin.

SUMMARY

These recent data indicate that fracture prevention with antiresorptives and teriparatide is effective with a reasonable safety profile. Odanacatib and antisclerostin are promising new drugs with new mechanisms of action, as they are able to disconnect the normal coupling between bone resorption and bone formation.

Efficacy and safety of currently marketed anti-osteoporosis medications

During the past 2 decades, many interventions were proven effective in the management of postmenopausal osteoporosis. The objective of an anti-osteoporosis treatment is to reduce fracture rates, ideally at all skeletal sites (i.e. spine, hip, and other non-spine). The armamentarium against osteoporosis includes anti-resorptive agents (i.e. bisphosphonates, selective estrogen receptor modulators and denosumab), bone-forming agents (i.e. peptides from the parathyroid hormone family) and one agent with a dual mechanism of action (i.e. strontium ranelate). All these medications combine antifracture efficacy with a reasonable benefit/risk profile. However, the choice of a particular chemical entity, in one individual patient is based on the knowledge and expertise of the physician. Prioritization of drugs should be based on the individual profile of the patient, the severity of osteoporosis and the specific contraindications, warnings and precautions of use of the various available medications.

New strategies for osteoporosis patients previously managed with strontium ranelate

The aim of this article is to describe potential alternatives to patients no longer eligible for management with strontium ranelate for osteoporosis according to the recommendations by the European Medicines Agency. A systematic search of Pubmed was done for papers on fracture efficacy of various treatments for osteoporosis, and potential harms especially in terms of cardiovascular events and stroke. The results showed that drugs more efficacious in terms of relative risk reduction of fractures than strontium ranelate were alendronate, risedronate, zoledronate, and denosumab. Raloxifene, as for strontium, may be associated with an increased risk of deep venous thromboembolism and fatal stroke. In terms of cardiovascular events special attention may be given to calcium supplements. Thus, patients at risk of stroke and ischemic cardiac events such as acute myocardial infarction should not use strontium ranelate. Ideally more efficacious drugs in terms of fracture reduction should be used such as alendronate, risedronate, zoledronate or denosumab. Raloxifene may pose a special problem as this too may be associated with an increased risk of fatal strokes. Other less-potent drugs in terms of fracture reduction should only be used if no alternatives are available (ibandronate, pamidronate, clodronate). Parathyroid hormone or analogs may be used for a limited time interval in specially selected patients and needs to be followed up with antiresorptive treatment to prevent loss of the bone gained. However, it should be remembered that no head-to-head comparison studies exist.

Cardiac concerns associated with strontium ranelate

Introduction: Strontium ranelate is proven to reduce vertebral and non-vertebral fracture risk in osteoporosis. Concerns about cardiac safety have led to a new contraindication to strontium ranelate in patients with uncontrolled hypertension and/or current or past history of ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease.

Areas covered: A literature search was performed; data were also collected from the European Medicines Agency website. Randomised controlled trial (RCT) data indicate a higher incidence of non-adjudicated myocardial infarction (MI) with strontium ranelate versus placebo (1.7 vs 1.1%; odds ratio [OR]: 1.6; 95% CI: 1.07 – 2.38; p = 0.020) (Mantel-Haenzel estimate of the OR). There was no increase in cardiovascular mortality. MI risk was mitigated by excluding patients with cardiovascular contraindications (OR: 0.99; 95% CI: 0.48 – 2.04; p = 0.988). Three observational studies performed in the context of real-life medical practice in the UK and Denmark did not report a signal.

Expert opinion: The increased risk for cardiac events with strontium ranelate has been detected in RCTs but not in real life. Excluding patients with cardiovascular contraindications appears to be an effective measure for controlling the risk of MI. Strontium ranelate remains a useful therapeutic alternative in patients with severe osteoporosis without cardiovascular contraindications who are unable to take another osteoporosis treatment.