Bone density changes with once weekly risedronate in postmenopausal women

Advanced glycation end products play adverse proinflammatory activities in osteoporosis

Osteoporosis is a major public health burden that is expected to further increase as the global population ages. In the last twenty years, advanced glycation end products (AGEs) have been shown to be critical mediators both in the pathogenesis and development of osteoporosis and other chronic degenerative diseases related to aging. The accumulation of AGEs within the bone induces the formation of covalent cross-links with collagen and other bone proteins which affects the mechanical properties of tissue and disturbs bone remodelling and deterioration, underlying osteoporosis. On the other hand, the gradual deterioration of the immune system during aging (defined as immunosenescence) is also characterized by the generation of a high level of oxidants and AGEs. The synthesis and accumulation of AGEs (both localized within the bone or in the systemic circulation) might trigger a vicious circle (in which inflammation and aging merged in the word "Inflammaging") which can establish and sustain the development of osteoporosis. This narrative review will update the molecular mechanisms/pathways by which AGEs induce the functional and structural bone impairment typical of osteoporosis.

Transplantable delivery systems for in situ controlled release of bisphosphonate in orthopedic therapy

IMPORTANCE OF THE FIELD

Bisphosphonates (BPs), structurally similar to pyrophosphates and functionally superior in restraining osteoclast-induced bone resorption, have been widely used as clinical drugs in the treatment of osteoporosis, bone voids and associated inflammation. However, owing to their high aqueous solubility and the consequently high rate of loss during oral administration, the loading and targeting of BPs pose major challenges in practice. Alternative delivery routes such as nasal, subcutaneous/intramuscular injection have contributed little to improving the bioavailiability and efficacy of BPs. To improve and optimize the delivery efficiency and efficacy of BPs, numerous strategies have been developed and adopted. Studies on controlled release of BPs provide important information on the fabrication of BP delivery systems for in situ treatment. As BPs play an important therapeutic role in osteoporosis and similar diseases, it has become essential and vital to survey various reported fabrication methodologies of these systems and the consequential orthopedic treatments so as to keep abreast with advances in their clinical use.

AREAS COVERED IN THIS REVIEW

Transplantable delivery systems for controlled release of BP are reviewed from literature published since 2000. The fabrication pathways and the release of BPs from various material systems are discussed in case studies. Recent progress in CaP models based on the strong and specific chelation between BPs and calcium phosphate crystals is highlighted.

WHAT THE READER WILL GAIN

This review offers an outline of the advances in BP controlled release and delivery systems for orthopedic therapy.

TAKE HOME MESSAGE

Understanding the cutting-edge BP controlled release and delivery systems for in situ treatment is key to the successful design of a more promising and perfect delivery system for orthopedic therapy. Moreover, developing such delivery systems incorporating the numerous advantages of BPs and controlled release environment requires substantially more flexible models to control better the fate of BP drugs.

Changes in non-enzymatic glycation and its association with altered mechanical properties following 1-year treatment with risedronate or alendronate

SUMMARY

One year of high-dose bisphosphonate (BPs) therapy in dogs allowed the increased accumulation of advanced glycation end-products (AGEs) and reduced postyield work-to-fracture of the cortical bone matrix. The increased accumulation of AGEs in these tissues may help explain altered bone matrix quality due to the administration of BPs in animal models

INTRODUCTION

Non-enzymatic glycation (NEG) is a posttranslational modification of the organic matrix that results in the formation of advanced glycation end-products (AGEs). In bone, the accumulation of AGEs play an important role in determining fracture resistance, and elevated levels of AGEs have been shown to adversely affect the bone's propensity to brittle fracture. It was thus hypothesized that the suppression of tissue turnover in cortical bone due to the administration of bisphosphonates would cause increased accumulation of AGEs and result in a more brittle bone matrix.

METHODS

Using a canine animal model (n = 12), we administered daily doses of a saline vehicle (VEH), alendronate (ALN 0.20, 1.00 mg/kg) or risedronate (RIS 0.10, 0.50 mg/kg). After a 1-year treatment, the mechanical properties, intracortical bone turnover, and the degree of nonenzymatic cross-linking of the organic matrix were measured from the tibial cortical bone tissue of these animals.

RESULTS

There was a significant accumulation of AGEs at high treatment doses (+49 to + 86%; p < 0.001), but not at doses equivalent to those used for the treatment of postmenopausal osteoporosis, compared to vehicle. Likewise, postyield work-to-fracture of the tissue was significantly reduced at these high doses (-28% to -51%; p < 0.001) compared to VEH. AGE accumulation inversely correlated with postyield work-to-fracture (r (2) = 0.45; p < 0.001), suggesting that increased AGEs may contribute to a more brittle bone matrix.

CONCLUSION

High doses of bisphosphonates result in the accumulation of AGEs and a reduction in energy absorption of cortical bone. The increased accumulation of AGEs in these tissues may help explain altered bone matrix quality due to the administration of BPs in animal models.

DXA scanning in clinical practice

Dual-energy X-ray absorptiometry (DXA) is recognized as the reference method to measure bone mineral density (BMD) with acceptable accuracy errors and good precision and reproducibility. The World Health Organization (WHO) has established DXA as the best densitometric technique for assessing BMD in postmenopausal women and based the definitions of osteopenia and osteoporosis on its results. DXA allows accurate diagnosis of osteoporosis, estimation of fracture risk and monitoring of patients undergoing treatment. However, when DXA studies are performed incorrectly, it can lead to major mistakes in diagnosis and therapy. This article reviews the fundamentals of positioning, scan analysis and interpretation of DXA in clinical practice.

The aminobisphosphonate risedronate preserves localized mineral and material properties of bone in the presence of glucocorticoids

OBJECTIVE

Glucocorticoids (GCs) alter bone strength such that patients receiving these medications have a high rate of fragility-related fractures. The purpose of this study was to assess whether concurrent treatment with GCs (prednisolone) and risedronate (an aminobisphosphonate) would prevent the reduction in bone strength induced by GCs, in a mouse model of GC-induced bone loss and in patients enrolled in a clinical study.

METHODS

We evaluated mice treated with prednisolone pellets alone, GCs plus risedronate, or placebo alone and iliac crest biopsy specimens obtained from patients who were treated with GCs plus placebo or GCs plus risedronate for 1 year. We measured the mass, architecture, and physical and material properties of bone (subject to therapeutic treatments) at nanoscale to macroscopic dimensions, using synchrotron x-ray tomography, elastic modulus mapping, transmission electron microscopy, and small-angle x-ray scattering techniques.

RESULTS

GC treatment reduced trabecular bone mass, microarchitecture, and the degree of bone mineralization and elastic modulus within the trabeculae. Concurrent treatment with GCs and risedronate prevented the deterioration of trabecular bone architecture, reduced the degree of mineralization, and preserved elastic modulus within the trabeculae, in both mouse and human bone. In addition, treatment with risedronate plus GCs in mice appeared to preserve bone crystal orientation, compared with treatment with GCs alone.

CONCLUSION

Risedronate prevented the localized changes in mineral and material properties of bone induced by GCs, which may ultimately improve bone strength.

Monthly dosing with risedronate 50 mg on three consecutive days a month compared with daily dosing with risedronate 5 mg: a 6-month pilot study

OBJECTIVE

Risedronate 5 mg daily significantly reduces the incidence of vertebral and non-vertebral osteoporotic fractures in postmenopausal women. We compared the efficacy and tolerability of risedronate 50 mg administered on 3 consecutive days per month, with and without a loading dose, with those of risedronate 5 mg daily in a randomized, double-blind study.

METHODS

Subjects were postmenopausal women 65-80 years old with low bone mineral density (BMD) (T-score < or = -2). Subjects received risedronate 5 mg daily for 6 months (n = 48), risedronate 150 mg (50-mg doses on 3 consecutive days) monthly for 6 months (n = 50), or a loading dose of risedronate 15 mg daily for 1 month followed by 150 mg (50-mg doses on 3 consecutive days) monthly for 5 months (n = 52).

RESULTS

Within 1 week, statistically significant reductions in urine N-telopeptide, the primary efficacy measure, were observed in all three groups. After 6 months, the least squares (LS) mean differences (95% confidence intervals [CI]) from the change in the 5 mg daily group (-39.88) were -3.54% (-15.71; 8.64) for the 150 mg monthly and -2.02% (-14.13;10.10) for the loading dose + 150 mg monthly groups. Mean percent changes in serum alpha-C-telopeptide, bone-specific alkaline phosphatase, and BMD, secondary efficacy measures, after 6 months were also similar for the three groups. The LS mean differences (95% CI) from the mean percent change in BMD in the 5 mg daily group (3.22%) were 0.20 (-1.15; 1.55) for the 150 mg monthly and -0.58 (-1.93; 0.76) for the loading dose + 150 mg monthly groups. The safety profile of the monthly regimens was similar to that of the 5 mg daily regimen and consistent with product labeling.

CONCLUSIONS

A monthly regimen of risedronate 50 mg on 3 consecutive days per month was similar to risedronate 5 mg daily with respect to its effect in suppressing bone turnover and increasing BMD and its safety profile in women with postmenopausal osteoporosis. This study was not powered to be a confirmatory trial for non-inferiority; therefore, additional study is needed.

Risedronate reduces postoperative bone resorption after cementless total hip arthroplasty

Forty-three patients who had undergone cementless THA were randomly assigned to receive no osteoactive drug or oral risedronate for 6 months. Postoperative decrease of BMD in the risedronate group was significantly lower than that seen in the control group in zones 1, 2, 3, 6, and 7.

INTRODUCTION

Proximal bone resorption around the femoral stem often has been observed after total hip arthroplasty (THA), could lead to late stem loosening. We previously reported the efficacy of etidronate on periprosthetic bone resorption after cementless THA. Recently risedronate is suggested to be effective for the prevention and treatment of for osteoporosis. The purpose of the present study was to evaluate the effects of risedronate on periprosthetic bone loss after cementless THA.

METHODS

Forty-three patients who had undergone cementless THA were randomly assigned to receive no osteoactive drug (21 patients) or oral risedronate 2.5 mg/day (22 patients) for 6 months. Three patients were eliminated from the risedronate group because of dyspepsia. Periprosthetic bone mineral density (BMD) in seven regions of interest based on the zones of Gruen et al. was measured with dual energy X-ray absorptiometry at 3 weeks and 6 months postoperatively.

RESULTS

At 6 months after surgery, postoperative decrease of BMD in the risedronate group was significantly lower than that seen in the control group in zones 1, 2, 3, 6, and 7 (p < 0.05, p < 0.01, p < 0.01, p < 0.05, and p < 0.05, respectively).

CONCLUSION

These outcomes suggested that risedronate might reduce the periprosthetic bone resorption after cementless THA.

Update on osteoporosis therapy

Osteoporosis is a skeletal disorder characterized by compromised bone strength that predisposes a person to increased fracture risk. Fractures are often associated with increased morbidity, higher mortality, loss of function and even psychological consequences. Pharmacotherapeutic interventions (e.g., bisphosphonates, selective estrogen receptor modulators, calcitonin, and teriparatide) in women with postmenopausal osteoporosis provide substantial reduction in fracture risk over and above risk reduction with calcium and vitamin D supplementation alone. The importance of nutritional support along with an appropriate exercise regimen, avoiding smoking and excessive alcohol use is to be emphasized along with the pharmacologic approach to osteoporosis. Despite the effectiveness of therapy with pharmacologic agents, most patients who start therapy do not remain on treatment for more than 1 year.

Preventing osteoporosis-related fractures: an overview

Osteoporosis is a skeletal disorder characterized by compromised bone strength, which predisposes a person to increased risk of fracture. In the United States, 26% of women aged > or =65 years and >50% of women aged > or =85 years have osteoporosis. Over 1.5 million fractures per year are attributable to osteoporosis; these fractures result in 500,000 hospitalizations, 800,000 emergency room visits, 2.6 million physician visits, 180,000 nursing home placements, and 12 billion dollars to 18 billion dollars in direct healthcare costs each year. Fracture also results in loss of function and has a negative impact on psychological status. In recognition of the importance of bone health, the US Surgeon General has, for the first time, issued a comprehensive report on bone health and treatment. The report recommends a pyramidal approach to osteoporosis treatment that includes calcium and vitamin D supplementation, physical activity, and fall prevention as the first line in fracture prevention. The second level consists of treating secondary causes of osteoporosis; the third and top level consists of pharmacotherapy. Pharmacotherapeutic interventions (e.g., bisphosphonates, selective estrogen receptor modulators, calcitonin, and teriparatide) in women with postmenopausal osteoporosis provide substantial reduction in fracture risk over and above risk reduction with calcium and vitamin D supplementation alone. Despite the effectiveness of therapy, most patients who receive treatment do not remain on treatment for >1 year. An important approach to reducing the rate of fractures is first to target our treatments to patients at high risk for fracture and then to develop strategies to improve treatment continuation rates.

Oral ibandronate in the management of postmenopausal osteoporosis: Review of upper gastrointestinal safety

Oral daily bisphosphonates carry a potential for gastrointestinal (GI) adverse events, which has been partly addressed by introducing once-weekly regimens. Nevertheless, the need to follow inconvenient dosing instructions every week could still hinder long-term compliance and therapeutic outcome. In addition, survey data indicates that many patients would prefer a once-monthly rather than once-weekly bisphosphonate dosing regimen. Ibandronate is a potent, nitrogen-containing bisphosphonate specifically developed for less frequent administration. In a pivotal study in postmenopausal osteoporosis, oral ibandronate, administered daily or with a between-dose interval of >2 months, demonstrated robust antifracture efficacy and an overall incidence of upper GI adverse events similar to placebo, even in patients at increased risk of such events. This and other clinical studies conducted in postmenopausal women demonstrate that oral ibandronate has an excellent upper GI safety profile.

Beyond daily dosing: clinical experience

Osteoporosis has had a significant public health impact, with many sufferers experiencing fractures. Such fractures lead to increased disability, mortality and reduced quality of life, all of which raise healthcare costs. Oral bisphosphonates are associated with significant antifracture efficacy and have therefore become the mainstay of treatment for postmenopausal osteoporosis. Poor therapeutic adherence with daily bisphosphonates has been improved by the introduction of weekly regimens, although adherence levels remain suboptimal. Bisphosphonate regimens with dosing intervals beyond a week have therefore been developed to address this issue. Oral ibandronate, a potent nitrogen-containing bisphosphonate, has been studied using daily and intermittent regimens (between-dose interval >2 months). The initial phase II 2-year study confirmed the feasibility of the intermittent regimen, providing increases in lumbar spine bone mineral density (BMD) superior to placebo (P < 0.01) and equivalent to the daily regimen (5.64% vs. 5.54%, respectively). BONE (Oral iBandronate Osteoporosis vertebral fracture trial in North America and Europe), a large phase III 3-year study was subsequently initiated, including 2946 women with postmenopausal osteoporosis and testing both a daily as well as an intermittent regimen with a dose-free interval of more than 2 months. Significant vertebral antifracture efficacy (the primary study endpoint) was demonstrated with daily (2.5 mg) and intermittent (20 mg every other day for 12 doses every 3 months) ibandronate in comparison with placebo (P < or = 0.0006). As a result of the study not being designed and powered to show an effect on non-vertebral fractures and the overall population being at low risk for osteoporotic fractures, differences in the incidence of non-vertebral fractures were similar between groups (8.2-9.1%) However, a post hoc analysis in a subgroup of patients with a femoral neck BMD T-score < -3.0 showed that daily ibandronate significantly reduced the risk of non-vertebral fractures (P = 0.012). Both regimens were associated with significant increases in lumbar spine and proximal femur BMD and normalization of bone turnover. As determined by adverse event incidence and laboratory evaluation, the safety profile for both ibandronate regimens was similar to that observed for placebo. The BONE study therefore confirmed that daily or intermittent ibandronate is an effective and well-tolerated treatment for postmenopausal women. Being the first study to demonstrate antifracture efficacy with an intermittent regimen, it provided "proof of concept" for beyond weekly dosing with ibandronate and prompted further development of a more convenient once-monthly regimen.

Risedronate for prevention and treatment of osteoporosis in postmenopausal women

Risedronate sodium is an N-containing bisphosphonate that has been approved for the prevention and treatment of osteoporosis in postmenopausal women. An increase in the rate of bone remodelling is a regular feature of oestrogen withdrawal during the menopausal transition, but excessive remodelling leads to bone fragility. Risedronate and similar compounds reduce the rate of bone remodelling by suppressing the action of osteoclasts. The antifracture efficacy of risedronate is impressive. In large clinical trials of postmenopausal women with osteoporosis-related fracture(s) at entry, the risk of incident vertebral and non-vertebral fractures was reduced by approximately 40%. In older women at risk for hip fracture, incident hip fractures were also reduced by approximately 40%. Antifracture efficacy develops within the first 6 months, and treatment has been followed for as long as 5 years without deleterious effects on bone. We await reports of experience with risedronate in 'real-world' cases of greater complexity (i.e., in patients with co-morbidities and medications that would have excluded them from published clinical trials).

Prevention and treatment of postmenopausal osteoporosis

Osteoporosis is a systemic disease characterized by low bone mass and microarchitectural deterioration of the skeleton leading to enhanced bone fragility and an increased risk of fracture. Prior to fracture, diagnosis is established by documenting low bone mass. In the first section of this article we review the clinical use of bone mass measurements and biochemical markers of bone remodeling in selecting patients most in need of preventive therapy at menopause. Women with high bone turnover lose bone at menopause more rapidly than those with normal bone turnover and are more likely to derive benefit from the several preventive therapies available. The second section addresses the available technologies used to diagnose osteoporosis and/or establish fragility fracture risk using noninvasive bone mass measurement and biochemical markers of bone remodeling separately or in combination. In the third section we review the several treatment options available for patients with osteoporosis, including alendronate (alendronic acid), risendronate (risedronic acid), calcitonin, teriparatide, and raloxifene, and the approaches to monitoring the therapeutic response. The final section deals with fall protection--an often forgotten aspect of management of the patient at risk for sustaining and osteoporotic fragility fracture.

The effect of prophylactic treatment with risedronate on stress fracture incidence among infantry recruits

When subjected to strains or strain rates higher than usual, the bone remodels to repair microdamage and to strengthen itself. During the initial resorption phase of remodeling, the bone is transitorily weakened and microdamage can accumulate leading to stress fracture. To determine whether short-term suppression of bone turnover using bisphosphonates can prevent the initial loss of bone during the remodeling response to high bone strain and strain rates and potentially prevent stress fracture, we conducted a randomized, double-blind, placebo-controlled trial of 324 new infantry recruits known to be at high risk for stress fracture. Recruits were given a loading dose of 30 mg of risedronate or placebo daily for 10 doses during the first 2 weeks of basic training and then a once a week maintenance dose for the following 12 weeks. Recruits were monitored by biweekly orthopedic examinations during 15 weeks of basic training for stress fractures. Bone scans for suspected tibial and femoral stress fractures and radiographs for suspected metatarsal stress fractures were used to verify stress fracture occurrence. By the intention-to-treat analysis and per-protocol analysis, there was no statistically significant difference in the tibial, femoral, metatarsal, or total stress fracture incidence between the treatment group and the placebo. We conclude that prophylactic treatment with risedronate in a training population at high risk for stress fracture using a maintenance dosage for the treatment of osteoporosis does not lower stress fracture risk.