The effect of prior bisphosphonate therapy on the subsequent BMD and bone turnover response to strontium ranelate

The Role of Macronutrients, Micronutrients and Flavonoid Polyphenols in the Prevention and Treatment of Osteoporosis

Osteoporosis is considered an age-related disorder of the skeletal system, characterized primarily by decreased bone mineral density (BMD), microstructural quality and an elevated risk of fragility fractures. This silent disease is increasingly becoming a global epidemic due to an aging population and longer life expectancy. It is known that nutrition and physical activity play an important role in skeletal health, both in achieving the highest BMD and in maintaining bone health. In this review, the role of macronutrients (proteins, lipids, carbohydrates), micronutrients (minerals—calcium, phosphorus, magnesium, as well as vitamins—D, C, K) and flavonoid polyphenols (quercetin, rutin, luteolin, kaempferol, naringin) which appear to be essential for the prevention and treatment of osteoporosis, are characterized. Moreover, the importance of various naturally available nutrients, whether in the diet or in food supplements, is emphasized. In addition to pharmacotherapy, the basis of osteoporosis prevention is a healthy diet rich mainly in fruits, vegetables, seafood and fish oil supplements, specific dairy products, containing a sufficient amount of all aforementioned nutritional substances along with regular physical activity. The effect of diet alone in this context may depend on an individual’s genotype, gene-diet interactions or the composition and function of the gut microbiota.

Rutin Improves Bone Histomorphometric Values by Reduction of Osteoclastic Activity in Osteoporosis Mouse Model Induced by Bilateral Ovariectomy

Objective

Osteoporosis is a disease of unbalanced bone metabolism that results in low bone mineral density with increased bone fragility and propensity for fractures. The increased rate of bone fracture due to osteoporosis places a significant burden on public health care expenditures. Therefore, numerous studies have been designed and performed to identify the drugs or health foods that can improve the bone quality or quantity. This study was designed to evaluate and analyze the therapeutic effects of rutin on histomorphometric values of the spine and femur in an osteoporotic mouse model induced by bilateral ovariectomy.

Methods

Thirty female ICR mice (8 weeks old) underwent either a sham operation (only abdominal incision, sham group, n=10) or bilateral ovariectomy (n=20). The ovariectomized (OVX) animals were randomly divided into two groups : untreated OVX group (OVX-C, n=10), or rutin-administered group (OVX-R, n=10). The OVX-C group received weight-adjusted doses of saline vehicle and the OVX-R group received 50 mg/kg of rutin intraperitoneally, starting 1 day after surgery. At 4 and 8 weeks after surgery, serum estrogen, osteocalcin, alkaline phosphatase (ALP), and the telopeptide fragment of type I collagen C-terminus (CTX-1) were analyzed. Interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α were also analyzed. Bone histomorphometric parameters of the 4th lumbar vertebra and femur were determined by micro-computed tomography.

Results

In OVX-C group, ALP, osteocalcin, CTX-1, IL-1β, IL-6, and TNF-α levels were significantly increased at 4 and 8 weeks compared to sham operation group. Rutin administration after OVX statistically significantly reduced ALP, CTX-1, IL-1β, IL-6, and TNF-α levels at 4 and 8 weeks. Rutin administration also improves bone histomorphometric parameters including trabecular bone volume fraction, trabecular thickness, and trabecular number. Trabecular separation was also decreased in OVX-R group compared to OVX-C group.

Conclusion

The present study demonstrated that rutin has therapeutic effects on improving bone histomorphometric values in an OVX mouse model. The improvement in histomorphometric values may be associated with the reduction of osteoclastic activity via inhibition of IL-1β, IL-6, and TNF-α. In future studies, the mechanism for the effect of rutin on osteoporosis should be demonstrated more clearly to use rutin in human osteoporosis.

Effect of Denosumab on Bone Mineral Density and Markers of Bone Turnover among Postmenopausal Women with Osteoporosis

The aim of this study was to evaluate the effect of denosumab (Dmab) on bone mineral density (BMD) and bone turnover markers after 1 year of treatment. Additionally, the effect of Dmab in bisphosphonate-naïve patients (BP-naïve) compared to patients previously treated with bisphosphonates (BP-prior) was analyzed. This retrospective study included 425 postmenopausal women treated with Dmab for 1 year in clinical practice conditions in specialized centers from Argentina. Participants were also divided according to previous bisphosphonate treatment into BP-naïve and BP-prior. A control group of patients treated with BP not switched to Dmab matched by sex, age, and body mass index was used. Data are expressed as mean ± SEM. After 1 year of treatment with Dmab the bone formation markers total alkaline phosphatase and osteocalcin were significantly decreased (23.36% and 43.97%, resp.), as was the bone resorption marker s-CTX (69.61%). Significant increases in BMD were observed at the lumbar spine, femoral neck, and total hip without differences between BP-naïve and BP-prior. A better BMD response was found in BP-prior group compared with BP treated patients not switched to Dmab. Conclusion. Dmab treatment increased BMD and decreased bone turnover markers in the whole group, with similar response in BP-naïve and BP-prior patients. A better BMD response in BP-prior patients versus BP treated patients not switched to Dmab was observed.

Treatment of osteoporosis after alendronate or risedronate

Alendronate (ALN) and risedronate (RIS) are ideal as first-choice therapy options in the treatment of postmenopausal osteoporosis. What to do for patients who do not respond adequately to bisphosphonates has not been conclusively determined, but transitioning to other therapies should be considered. The aim of this article is to describe potential alternatives for patients switching from ALN or RIS to other therapies for osteoporosis. A systematic search of PubMed was conducted to find papers that evaluate the effects of switching therapies on fractures, bone mineral density (BMD), or bone turnover markers. Results from 11 studies that prospectively assessed treatment after ALN or RIS in women with postmenopausal osteoporosis were reviewed. All studies are of short duration (all 24 months or less) and assess the topic of transitioning therapy from ALN or RIS. None of the studies had the statistical power to assess fracture-reduction efficacy. Transitioning from ALN to zoledronic acid maintains therapeutic effects for 12 months. Switching to strontium ranelate, denosumab, or teriparatide causes further increases in BMD. Specifically, transitioning to teriparatide could be used for a limited time for select patients but needs to be followed up with anti-resorptive treatment to prevent a loss of the bone gained. There are only few studies-of short duration-that assess the topic of transitioning therapy from ALN or RIS, although this is a very frequent occurrence in clinical practice. This is especially true if the patient has not reached his/her therapy goal. Further long-term studies are needed.

Strontium ranelate effect on bone mineral density is modified by previous bisphosphonate treatment

The aim of this study was to evaluate the effect of strontium ranelate (SrR) on bone mineral density (BMD) and bone turnover markers after 1 year of treatment. Additionally, the effect of SrR in bisphosphonate-naïve patients (BP-naïve) compared to patients previously treated with bisphosphonates (BP-prior) was analyzed. This retrospective study included 482 postmenopausal women treated with SrR (2 g/day) for 1 year in ten Argentine centers; 41 patients were excluded due to insufficient data, while 441 were included. Participants were divided according to previous bisphosphonate treatment in two groups: BP-naïve (n = 87) and BP-prior (n = 350). Data are expressed as mean ± SEM. After 1 year of treatment with SrR the bone formation markers total alkaline phosphatase and osteocalcin were increased (p < 0.0001), while the bone resorption marker s-CTX was decreased (p = 0.0579). Also increases in BMD at the lumbar spine (LS, 3.73%), femoral neck (FN, 2.00%) and total hip (TH, 1.54%) [p < 0.0001] were observed. These increments were significant (p < 0.0001) both among BP-naïve and BP-prior patients. Interestingly, the change in BMD after 1 year of SrR treatment was higher in BP-naïve patients: LS: BP-naïve = 4.58 ± 0.62%; BP-prior = 3.45 ± 0.28% (p = 0.078). FN: BP-naïve = 2.79 ± 0.56%; BP-prior = 2.13 ± 0.29% (p = 0.161). TH: BP-naïve = 3.01 ± 0.55%; BP-prior = 1.22 ± 0.27% (p = 0.0006). SrR treatment increased BMD and bone formation markers and decreased a bone resorption marker in the whole group, with better response in BP-naïve patients.

Trajectories of Bone Remodeling Markers and Bone Mineral Density during Treatment with Strontium Ranelate in Postmenopausal Women Previously Treated with Bisphosphonates

OBJECTIVE

To evaluate the responses of C-terminal telopeptide (CTX) and serum osteocalcin after the first 4 months of treatment with strontium ranelate (SR) and demonstrate their association with long-term bone density changes.

SUBJECTS AND METHODS

A sample of 13 postmenopausal women with osteoporosis was analyzed (mean age 65 ± 7.7 years), who were treated with SR for an average of 2.56 ± 0.86 years. All patients had undergone previous treatment with bisphosphonates for an average period of 4.88 ± 2.27 years. Serum CTX and osteocalcin levels were determined before and after four months of treatment with SR. Bone mineral density in the lumbar spine and femoral neck were obtained before and after treatment with SR.

RESULTS

We observed an average increase of 53.7% in the CTX levels, and 30.7% in the osteocalcin levels. The increase in bone markers was associated with a mean 4.8% increase in lumbar spine bone mineral density (BMD) from 0.820 to 0.860 g/cm² (T-score from −2.67 to −1.92; P = 0.001), after 2.5 years of treatment with SR.

CONCLUSION

These data suggest an anabolic effect of SR on postmenopausal women who were previously treated with long-term bisphosphonates.

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

Guidance is provided in a European setting on the assessment and treatment of postmenopausal women at risk of fractures due to osteoporosis.

INTRODUCTION

The International Osteoporosis Foundation and European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis published guidance for the diagnosis and management of osteoporosis in 2008. This manuscript updates these in a European setting.

METHODS

Systematic literature reviews.

RESULTS

The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporosis and assessment of fracture risk, general and pharmacological management of osteoporosis, monitoring of treatment, assessment of fracture risk, case finding strategies, investigation of patients and health economics of treatment.

CONCLUSIONS

A platform is provided on which specific guidelines can be developed for national use.

The use of combination therapy in the treatment of postmenopausal osteoporosis

In recent years, there has been growing interest in the potential use of combination therapy in the management of osteoporosis in postmenopausal women. Possible regimens include sequential or combined use of anti-resorptive drugs or combinations of anabolic and anti-resorptive agents, given concurrently or in sequence. Combined therapy with anti-resorptive drugs usually produces greater increases in bone mineral density (BMD) than monotherapy but there is no evidence that this results in greater anti-fracture efficacy. The use of bisphosphonates before strontium ranelate or PTH peptides blunts the BMD response. Combined PTH and anti-resorptive therapy results in more rapid gains in spine BMD and a greater increase in hip BMD than PTH monotherapy in the first year of treatment but greater gains in both spine and hip BMD are seen with PTH monotherapy than combined therapy after 2 years of treatment. Anti-resorptive therapy after PTH therapy maintains or increases the gains in BMD. Further research is required to establish the cost-effectiveness and safety of combined and sequential regimens.

The effect of prior bisphosphonate therapy on the subsequent therapeutic effects of strontium ranelate over 2 years

Many osteoporotic women prescribed strontium ranelate have previously received bisphosphonates. Prior bisphosphonate use blunted the spinal bone mineral density (BMD) response for 6 months. Hip BMD was blunted to a degree for 2 years, although there was an overall increase in hip BMD in contrast to the heel where BMD did not increase.

INTRODUCTION

Many osteoporotic women commenced on strontium ranelate have already received treatment with bisphosphonates. This study investigates whether prior bisphosphonate use impairs the subsequent therapeutic response to strontium ranelate.

METHODS

Women were recruited who were either bisphosphonate naïve or currently receiving a bisphosphonate. All women received strontium ranelate and were followed up for 2 years.

RESULTS

One hundred and twenty women were recruited. After 2 years, the bisphosphonate-naïve group had significant BMD increases of 8.9%, 6.0% and 6.4% at the spine, hip and heel, respectively. In the prior bisphosphonate group, BMD increased significantly at the spine (4.0%) and hip (2.5%) but not at the heel. At all time points at all sites, the BMD increase was greater in the bisphosphonate-naïve group. BMD at the spine did not increase during the first 6 months in the prior bisphosphonate group but then increased in parallel with the bisphosphonate-naïve group. In contrast, the difference between the two groups in hip BMD continued to increase throughout the 2 years. P1NP was suppressed in the prior bisphosphonate group for the first 6 months.

CONCLUSIONS

After bisphosphonate exposure, the BMD response to strontium ranelate is blunted for only 6 months at the spine. At the hip, a degree of blunting was observed over 2 years, although there was an overall increase in hip BMD in contrast to the heel where no increase in BMD was observed.

Sequential osteoporosis treatments

Osteoporosis is a major public health concern due both to its high prevalence and to its association with potentially serious fractures. The chronic nature of osteoporosis, together with the aging of the population, may result in a need for prolonged treatment consisting in the sequential use of several osteoporosis drugs. Situations in which switching from one osteoporosis drug to another may be considered include the occurrence of a fracture despite treatment, poor treatment adherence, side effects, and completion of a first-line treatment course. The available recommendations for postmenopausal women deal only with the indications for first-line osteoporosis treatment. Studies on drug sequences used an open-label design and failed to collect data on fractures. Thus, there is no scientific evidence supporting a specific treatment sequence, the only exception being teriparatide followed by a bone resorption inhibitor. Consequently, selection of the second drug in an osteoporotic woman is a matter of clinical judgment, which can be guided by several factors such as health insurance reimbursement restrictions, characteristics of the osteoporosis (e.g., severity and whether there is a predominant risk of peripheral fractures), co-morbidities, contraindications to specific drugs, and patient adherence to prescriptions.

Trabecular reorganization in consecutive iliac crest biopsies when switching from bisphosphonate to strontium ranelate treatment

BACKGROUND

Several agents are available to treat osteoporosis while addressing patient-specific medical needs. Individuals' residual risk to severe fracture may require changes in treatment strategy. Data at osseous cellular and microstructural levels due to a therapy switch between agents with different modes of action are rare. Our study on a series of five consecutively taken bone biopsies from an osteoporotic individual over a six-year period analyzes changes in cellular characteristics, bone microstructure and mineralization caused by a therapy switch from an antiresorptive (bisphosphonate) to a dual action bone agent (strontium ranelate).

METHODOLOGY/PRINCIPAL FINDINGS

Biopsies were progressively taken from the iliac crest of a female patient. Four biopsies were taken during bisphosphonate therapy and one biopsy was taken after one year of strontium ranelate (SR) treatment. Furthermore, serum bone markers and dual x-ray absorptiometry measurements were acquired. Undecalcified histology was used to assess osteoid parameters and bone turnover. Structural indices and degree of mineralization were determined using microcomputed tomography, quantitative backscattered electron imaging, and combined energy dispersive x-ray/µ-x-ray-fluorescence microanalysis.

CONCLUSIONS/SIGNIFICANCE

Microstructural data revealed a notable increase in bone volume fraction after one year of SR treatment compared to the bisphosphonate treatment period. Indices of connectivity density, structure model index and trabecular bone pattern factor were predominantly enhanced indicating that the architectural transformation from trabecular rods to plates was responsible for the bone volume increase and less due to changes in trabecular thickness and number. Administration of SR following bisphosphonates led to a maintained mineralization profile with an uptake of strontium on the bone surface level. Reactivated osteoclasts designed tunneling, hook-like intratrabecular resorption sites. The appearance of tunneling resorption lacunae and the formation of both mini-modeling units and osteon-like structures within increased plate-like cancellous bone mass provides additional information on the mechanisms of strontium ranelate following bisphosphonate treatment, which may deserve special attention when monitoring a treatment switch.

Osteal macrophages promote in vivo intramembranous bone healing in a mouse tibial injury model

Bone-lining tissues contain a population of resident macrophages termed osteomacs that interact with osteoblasts in vivo and control mineralization in vitro. The role of osteomacs in bone repair was investigated using a mouse tibial bone injury model that heals primarily through intramembranous ossification and progresses through all major phases of stabilized fracture repair. Immunohistochemical studies revealed that at least two macrophage populations, F4/80(+) Mac-2(-/low) TRACP(-) osteomacs and F4/80(+) Mac-2(hi) TRACP(-) inflammatory macrophages, were present within the bone injury site and persisted throughout the healing time course. In vivo depletion of osteomacs/macrophages (either using the Mafia transgenic mouse model or clodronate liposome delivery) or osteoclasts (recombinant osteoprotegerin treatment) established that osteomacs were required for deposition of collagen type 1(+) (CT1(+)) matrix and bone mineralization in the tibial injury model, as assessed by quantitative immunohistology and micro-computed tomography. Conversely, administration of the macrophage growth factor colony-stimulating factor 1 (CSF-1) increased the number of osteomacs/macrophages at the injury site significantly with a concurrent increase in new CT1(+) matrix deposition and enhanced mineralization. This study establishes osteomacs as participants in intramembranous bone healing and as targets for primary anabolic bone therapies.

Comparative effects of teriparatide and strontium ranelate in the periosteum of iliac crest biopsies in postmenopausal women with osteoporosis

The periosteum contains osteogenic cells that regulate the outer shape of bone and contribute to determine its cortical thickness, size and position. We assessed the effects of subcutaneous injections of teriparatide (TPTD, 20μg/day) or oral strontium ranelate (SrR, 2g/day) in postmenopausal women with osteoporosis on new bone formation activity at the periosteal and endosteal bone surfaces using dynamic histomorphometric measurements. Evaluable tetracycline-labeled transiliac crest bone biopsies were analyzed from 27 patients in the TPTD group, and 22 in the SrR group after six months of treatment. Measurements were conducted on the thicker and thinner cortices separately, and comparisons between the thicker, thinner and combined cortices were carried out. At the combined periosteal cortex, the mineralization surface as a percent of bone surface (MS/BS%) was greater for TPTD (mean±SE: 8.08±1.22%) than SrR (3.22±1.05%) (p<0.005). The difference in mineral apposition rate (MAR) between TPTD (0.35±0.06μm/day) and SrR (0.14±0.06μm/day) was also significant (p<0.05), while that of bone formation rate per bone surface (BFR/BS) between TPTD (0.014±0.004 mm(3)/mm(2)/year) and SrR (0.004±0.003 mm(3)/mm(2)/year) was not (p=0.057). Statistically significant differences between the two treatments were also observed for MS/BS%, BFR/BS, MAR and the double-labeled perimeter in the periosteum of the thicker, but not thinner, iliac crest cortices. The comparison between the thicker and thinner cortices of both periosteal and endosteal surfaces showed statistically significant differences for MAR and the double-labeled perimeter for TPTD treated women. There were no statistically significant differences in any bone formation dynamic measurements between the two cortices in the SrR group. In conclusion, most of the bone formation and mineralization variables were significantly higher for TPTD- than SrR-treated women at both the periosteal and endosteal combined cortices. The response to TPTD for dynamic bone formation measurements in the periosteal surface was greater for the thicker than thinner cortex, but this difference was not significant in SrR treated patients. This may reflect a greater ability of TPTD to enhance responsiveness of bone to the mechanical loading environment. These effects on bone formation may underlie the improvement in bone quality in patients with osteoporosis treated with TPTD.

The vitamin D analogue 2MD increases bone turnover but not BMD in postmenopausal women with osteopenia: results of a 1-year phase 2 double-blind, placebo-controlled, randomized clinical trial

Most osteoporosis drugs act by inhibiting bone resorption. A need exists for osteoporosis therapies that stimulate new bone formation. 2-Methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D(3) (2MD) is a vitamin D analogue that potently stimulates bone formation activity in vitro and in the ovariectomized rat model. In this randomized, double-blind, placebo-controlled study of osteopenic women, the effect of daily oral treatment with 2MD on bone mineral density (BMD), serum markers of bone turnover, and safety were assessed over 1 year. Volunteers were randomly assigned to three treatment groups: placebo (n = 50), 220 ng of 2MD (n = 54), and 440 ng of 2MD (n = 53). In general, 2MD was well tolerated. Although 2MD caused a marked increase in markers of bone formation, it did not significantly increase BMD. Since 2MD also shows marked activity on bone resorption (as revealed by dose-dependent increases in serum C-telopeptide cross-links of type I collagen in this study), 2MD likely stimulated both bone formation and bone resorption, thereby increasing bone remodeling.

Strontium ranelate: a review of its use in the treatment of postmenopausal osteoporosis

This is a review of the pharmacology of strontium ranelate (Protelos, Protos, Protaxos, Bivalos, Osseor), and its efficacy and tolerability in the treatment of patients with postmenopausal osteoporosis. Strontium ranelate is a divalent strontium salt of ranelic acid that is capable of increasing bone formation and reducing bone resorption, thereby uncoupling and rebalancing bone turnover in favour of bone formation. The drug is effective in reducing the risk of fractures, including both vertebral and nonvertebral fractures, in patients with postmenopausal osteoporosis, according to data from two large, double-blind, placebo-controlled, multicentre trials of 5 years' duration, and reduced the risk of hip fracture in high-risk patients in a post hoc analysis of one trial. Moreover, data from patients who continued to receive the drug during the 3-year extension phases of these trials indicate that strontium ranelate continues to provide protection against new vertebral fractures and nonvertebral fractures for up to 8 years of therapy. It also improves bone mineral density at numerous sites and both increases markers of bone formation and decreases markers of bone resorption. Strontium ranelate is administered orally as a suspension and is generally well tolerated. The nature of adverse events was generally similar regardless of treatment duration in clinical trials, with the most commonly reported being nausea and diarrhoea over 5 years of treatment, and memory loss and diarrhoea during longer-term treatment. Although an increased risk of venous thromboembolism was associated with strontium ranelate relative to placebo over 5 years of treatment in a pooled analysis of clinical trials, postmarketing data have not confirmed this finding. Overall, the clinical data available suggest that strontium ranelate is an effective and generally well tolerated option for the first-line treatment of postmenopausal osteoporosis.