Recent developments in bisphosphonate therapy

Effect of clindamycin on human osteoblasts treated with zoledronate: An in vitro study

OBJECTIVE

The objective of this study was to determine the effects of combined treatment with clindamycin and zoledronate on the growth and differentiation of cultured human osteoblasts.

DESIGN

Human osteoblasts, obtained by primary culture from mandibular bone fragments, were cultured in the presence of 50 μM zoledronate, 150 μg/mL clindamycin, or the combination of both (zoledronate + clindamycin). The effect on cell proliferation was evaluated at 24 h by the MTT colorimetric method, using a spectrophotometer at 570 nm. The effect on differentiation was examined by measuring alkaline phosphatase (ALP) activity, and mineralization by the osteoblast was studied by staining with alizarin red. Real-time polymerase chain reaction (RT-PCR) was performed for gene expression analysis. Data were expressed as means±standard deviation, and analysis of variance was performed, applying Bonferroni correction when interactions were significant.

RESULTS

Treatment of osteoblasts with 50 μM zoledronate significantly reduced cell proliferation and differentiation and the gene expression of certain markers versus controls (p < 0.001). However, treatment with 150 μg/mL clindamycin significantly increased cell proliferation and differentiation and the gene expression of certain markers (p < 0.05). The combination of 150 μg/mL clindamycin and 50 μM zoledronate partially counteracted the loss of osteoblast proliferative and differentiation capacity caused by zoledronate.

CONCLUSION

Treatment with low-dose clindamycin can reverse the negative impact of zoledronate on osteoblast proliferation and differentiation. Follow-up animal studies and clinical trials are needed before topical clindamycin can be considered as a possible therapeutic resource for BP-treated patients who require a GBR procedure.

Biomimetic Collagen Membranes as Drug Carriers of Geranylgeraniol to Counteract the Effect of Zoledronate

To counteract the effect of zoledronate and decrease the risk of osteonecrosis of the jaw (BRONJ) development in patients undergoing guided bone regeneration surgery, the use of geranylgeraniol (GGOH) has been proposed. Collagen membranes may act as biomimetical drug carriers. The objective of this study was to determine the capacity of collagen-based membranes doped with GGOH to revert the negative impact of zoledronate on the growth and differentiation of human osteoblasts. MG-63 cells were cultured on collagen membranes. Two groups were established: (1) undoped membranes and (2) membranes doped with geranylgeraniol. Osteoblasts were cultured with or without zoledronate (50 μM). Cell proliferation was evaluated at 48 h using the MTT colorimetric method. Differentiation was tested by staining mineralization nodules with alizarin red and by gene expression analysis of bone morphogenetic proteins 2 and 7, alkaline phosphatase (ALP), bone morphogenetic proteins 2 and 7 (BMP-2 and BMP-7), type I collagen (Col-I), osterix (OSX), osteocalcin (OSC), osteoprotegerin (OPG), receptor for RANK (RANKL), runt-related transcription factor 2 (Runx-2), TGF-β1 and TGF-β receptors (TGF-βR1, TGF-βR2, and TGF-βR3), and vascular endothelial growth factor (VEGF) with real-time PCR. One-way ANOVA or Kruskal-Wallis and post hoc Bonferroni tests were applied (p < 0.05). Scanning electron microscopy (SEM) observations were also performed. Treatment of osteoblasts with 50 μM zoledronate produced a significant decrease in cell proliferation, mineralization capacity, and gene expression of several differentiation markers if compared to the control (p < 0.001). When osteoblasts were treated with zoledronate and cultured on GGOH-doped membranes, these variables were, in general, similar to the control group (p > 0.05). GGOH applied on collagen membranes is able to reverse the negative impact of zoledronate on the proliferation, differentiation, and gene expression of different osteoblasts' markers.

Efficient lung-targeted delivery of risedronate sodium/vitamin D3 conjugated PAMAM-G5 dendrimers for managing osteoporosis: Pharmacodynamics, molecular pathways and metabolomics considerations

AIMS

This study aims at formulating combined delivery of Risedronate sodium (RIS) and Vitamin D3 (VITD3) for augmented therapeutic outcome against osteoporosis (OP) using deep lung targeted PAMAM-G5-NH2 dendrimers to minimize RIS gastrointestinal side effects and enhance both drugs bioavailability through absorption from the alveoli directly to the blood.

METHODS

RIS-PAMAM-G5-NH2, VITD3-PAMAM-G5-NH2, and RIS/VITD3-PAMAM-G5-NH2 were prepared and evaluated in vitro for particle size (PS), zeta potential (ZP), %loading efficiency (%LE), morphology and FTIR. The efficacy of the RIS/VITD3-PAMAM-G5-NH2 compared to oral RIS was evaluated in OP-induced rats by comparing serum calcium, phosphorus, and computed bone mineral density (BMD) pre- and post-treatment. Additionally, a comprehensive metabolomics and molecular pathways approach was applied to find serum potential biomarkers for diagnosis and to evaluate the efficacy of inhaled RIS/VITD3-PAMAM-G5-NH2.

KEY FINDINGS

RIS/VITD3-PAMAM-G5-NH2 was successfully prepared with a %LE of 92.4 ± 6.7 % (RIS) and 83.2 ± 4.4 % (VIT-D3) and a PS of 252.8 ± 34.1 adequate deep lung delivery. RIS/VITD3-PAMAM-G5-NH2 inhalation therapy was able to restore serum calcium, phosphorus, and BMD close to normal levels after 21 days of treatment in OP-induced rats. The WNT-signalling pathway and changes in the metabolite levels recovered to approximately normal levels upon treatment. Moreover, histone acetylation of the WNT-1 gene and miR-148a-3p interference proved to play a role in the regulation of the WNT-signalling pathway during OP progression and treatment.

SIGNIFICANCE

Pulmonary delivery of RIS/VITD3-PAMAM-G5-NH2 offers superior treatment for OP treatment compared to the oral route. Molecular and Metabolic pathways offer a key indicator of OP diagnosis and progression.

Evaluation of intravenous zoledronic acid-induced acute-phase response in the emergency department

Background/Aim: A temporary influenza-like condition, called acute-phase reaction (APR), is commonly observed with intravenous (IV) administration of nitrogen-containing amino bisphosphonates, such as zoledronic acid (ZOL). This single-center study aimed to evaluate the incidence of APR symptoms after intravenous (IV) ZOL administration in patients with postmenopausal osteoporosis who were admitted to emergency department (ED). Methods: In this cross-sectional study, 107 osteoporotic patients who were diagnosed with post-menopausal osteoporosis (bone mineral density T-score equal to or below −2.5 with/without prevalent fractures) and who had an ED admission in the first 72 h after intravenous injection of ZOL were included in the study. The patient’s pre-treatment blood sample measurements, presenting symptoms (such as fever, fatigue, hyperpyrexia, headache), family history, previous medical treatment, and adverse effects caused by osteoporosis drugs, in addition to information on co-morbidities and comedications were obtained from clinical records. Results: One-hundred seven osteoporotic patients (19.56%) patients experienced APR and were admitted to the ED after IV-ZOL administration. The mean age was 64.58 (11.15) years (n = 107). The three most commonly reported symptoms were diffuse musculoskeletal symptoms, influenza-like illness, and gastrointestinal symptoms (34.5%, 21.5%, and 18.5%, respectively). Seventy percent of the patients who presented to the ED with APR symptoms were prescribed drugs only, and 30% of the patients received treatment specific for their symptoms in the ED. Most of the diffuse musculoskeletal symptoms consisted of myalgia (22.4%). A positive correlation between the onset time of APR symptoms and the number of IV bisphosphonate (BP) doses was found (r = 0.597; P = 0.032). Conclusion: Our study indicates that as the number of IV-ZOL administrations increase yearly in patients with osteoporosis, symptom onset time occurs later. A linear relationship was found between the number of drug applications and the duration of symptoms. Also, the incidence of APR following IV-ZOL administration was 19% in the osteoporotic patient population who presented to the ED or to other clinics according to the symptoms.

Effect of low-level laser therapy on bisphosphonate-treated osteoblasts

BACKGROUND

This study investigates the effect of alendronate-treated osteoblasts, as well as the effect of low-level laser therapy (LLLT) on the alendronate-treated osteoblasts. Bisphosphonate decreases the osteoblastic activity. Various treatment modalities are used to enhance the bisphosphonate-treated osteoblasts; however, there were no cell culture studies conducted using a low-level laser.

METHODS

Human fetal osteoblastic (hFOB 1.19) cells were treated with 50 μM alendronate. Then, they were irradiated with a 1.2 J/cm2 low-level Ga-Al-As laser (λ = 808 ± 3 nm, 80 mW, and 80 mA; spot size, 1 cm2; NDLux, Seoul, Korea). The cell survivability was measured with the MTT assay. The three cytokines of osteoblasts, receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), and macrophage colony-stimulating factor (M-CSF) were analyzed.

RESULTS

In the cells treated with alendronate at concentrations of 50 μM and higher, cell survivability significantly decreased after 48 h (p < 0.05). After the applications of low-level laser on alendronate-treated cells, cell survivability significantly increased at 72 h (p < 0.05). The expressions of OPG, RANKL, and M-CSF have decreased via the alendronate. The RANKL and M-CSF expressions have increased, but the OPG was not significantly affected by the LLLT.

CONCLUSIONS

The LLLT does not affect the OPG expression in the hFOB cell line, but it may increase the RANKL and M-CSF expressions, thereby resulting in positive effects on osteoclastogenesis and bone remodeling.

Nanocomposite scaffolds with tunable mechanical and degradation capabilities: co-delivery of bioactive agents for bone tissue engineering

Novel multifunctional nanocomposite scaffolds made of nanobioactive glass and alginate crosslinked with therapeutic ions such as calcium and copper were developed for delivering therapeutic agents, in a highly controlled and sustainable manner, for bone tissue engineering. Alendronate, a well-known antiresorptive agent, was formulated into microspheres under optimized conditions and effectively loaded within the novel multifunctional scaffolds with a high encapsulation percentage. The size of the cation used for the alginate crosslinking impacted directly on porosity and viscoelastic properties, and thus, on the degradation rate and the release profile of copper, calcium and alendronate. According to this, even though highly porous structures were created with suitable pore sizes for cell ingrowth and vascularization in both cases, copper-crosslinked scaffolds showed higher values of porosity, elastic modulus, degradation rate and the amount of copper and alendronate released, when compared with calcium-crosslinked scaffolds. In addition, in all cases, the scaffolds showed bioactivity and mechanical properties close to the endogenous trabecular bone tissue in terms of viscoelasticity. Furthermore, the scaffolds showed osteogenic and angiogenic properties on bone and endothelial cells, respectively, and the extracts of the biomaterials used promoted the formation of blood vessels in an ex vivo model. These new bioactive nanocomposite scaffolds represent an exciting new class of therapeutic cell delivery carrier with tunable mechanical and degradation properties; potentially useful in the controlled and sustainable delivery of therapeutic agents with active roles in bone formation and angiogenesis, as well as in the support of cell proliferation and osteogenesis for bone tissue engineering.

Effect of Clodronate on Antigenic Profile, Growth, and Differentiation of Osteoblast-Like Cells

PURPOSE

To evaluate the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ) by studying the effects of different concentrations of clodronate, a non-nitrogen-containing bisphosphonate, on osteoblast growth, differentiation, and antigenic profile.

MATERIALS AND METHODS

Osteoblast-like cells (MG63) were incubated in culture medium with different doses of clodronate. Their proliferative capacity was determined with a spectrophotometric technique (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium assay). Flow cytometry was used to study the antigenic profile. Cell differentiation was evaluated by nodule formation and alkaline phosphatase (ALP) activity was measured by spectrophotometric assay.

RESULTS

Clodronate had a significant stimulatory effect on osteoblast-like cell (MG63) proliferation (P < .05). A significant decrease in the expression of CD54, CD80, CD86, and HLA-DR membrane antigens versus controls was observed after 24 hours of treatment with the different clodronate doses assayed (P < .05). A significant decrease (P = .004) in ALP activity was found after 24 hours of treatment with the lowest dose (10(-9) mol/L), and a significant decrease in calcium deposition was found after 15 and 21 days of treatment (P < .05).

CONCLUSION

Clodronate increases the proliferation of MG63 osteoblast-like cells and decreases their differentiation capacity, generally at low doses, and modulates the expression of costimulatory molecules associated with immune function. Clodronate exerts its effect on osteoblasts by altering their physiology and impairing their repair capacity, which could be related to the development of BRONJ. However, further research is warranted to elucidate fully the mechanisms by which bisphosphonates can produce this disease.

An evaluation of secondary prophylaxis for rheumatic heart disease in rural Egypt

Background: Although essentially disappeared from the industrialized world, rheumatic heart disease (RHD) is still prevalent in developing countries, with 300,000 new cases identified each year. In Aswan, Egypt, RHD affects about 2.3% of children with over 90% of the cases being subclinical. Secondary prophylaxis has proved to be an effective method of preventing the progression of RHD. However, its efficacy is limited by low patient adherence. A systematic, generalizable tool is necessary to outline, and ultimately address these barriers. Methods: A 43-item semi-structured questionnaire was developed based on the three domains outlined by Fishbein (capability, intention, and health care barriers). A preliminary evaluation of the barriers to RHD prophylaxis use in Aswan, Egypt was carried out as a pilot study using this tool. Participants were local school children diagnosed with RHD or flagged as high-risk (as per a set of echocardiographic criteria developed by the Aswan Heart Centre) through a previous screening program of randomly selected 3,062 school children in Aswan. Results: 29 patients were interviewed (65.5% adherent to RHD prophylaxis). Compared to non-adherent patients, adherent patients had better understanding of the disease (68.4% versus 20% in the non-adherent group, p = 0.021), and were more aware of the consequences of missing prophylaxis doses (79% versus 40% of non-adherent patients, p = 0.005). Furthermore, 90% of non-adherent patients consciously choose to miss injection appointments (as compared to 31.6% of adherent patients, p = 0.005). Clinic wait time was the most frequently reported deterrent for both groups. Conclusion: A standardized tool that systematically outlines barriers to prophylaxis is a necessary first step to improving adherence to penicillin. Although individually developed tools exist for specific populations, a generalizable tool that takes into account the demographic and cultural differences in the populations of interest will allow for more reliable data collection methodology. Application of this tool will be used to further explore barriers to prophylaxis adherence and inform the basis for the design of future KT interventions.

Biodegradable intranasal nanoparticulate drug delivery system of risedronate sodium for osteoporosis

CONTEXT

Osteoporosis (OP) is the most common metabolic bone disease predominantly found in elderly people. It is associated with reduced bone mineral density, results in a higher probability of fractures, especially of the hip, vertebrae, and distal radius. Worldwide prevalence of OP is considered a serious public health concern.

OBJECTIVE

The purpose of the present work was to develop and evaluate polymeric nanoparticles (NPs) of risedronate sodium (RIS) for the treatment of OP using intranasal (IN) route in order to reduce peripheral toxic effects.

MATERIALS AND METHODS

Polymeric NPs of RIS were prepared by nanoprecipitation methods. Formulations were developed and evaluated in context to in vitro drug release, ex vivo permeation, in vivo study, and biochemical studies.

RESULTS AND DISCUSSIONS

The particles size, entrapment efficiency (EE) (%), and loading capacity (LC) (%) of optimized formulations were found to be 127.84 ± 6.33 nm, 52.65 ± 5.21, and 10.57 ± 1.48, respectively. Release kinetics showed diffusion-controlled, Fickian release pattern. Ex vivo permeation study showed RIS from PLGA-NPs permeated significantly (p < 0.05) through nasal mucosa. In vivo study showed a marked difference in micro-structure (trabeculae) in bone internal environment. Biochemical estimation of treated group and RIS PLGA indicated a significant recovery (p < 0.01) as compared with the toxic group.

CONCLUSION

Polymeric NPs of RIS were prepared successfully using biodegradable polymer (PLGA). Intranasal delivery showed a good result in in vivo study. Thus PLGA-NPs have great potential for delivering the RIS for the treatment and prevention of OP after clinical evaluation in near future.

Legal liability in bisphosphonate-related osteonecrosis of the jaw

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is an adverse reaction that may occur in patients administered with bisphosphonates (BP). This condition can cause high morbidity and hinder quality of life. Its treatment is complex and often unsatisfactory, and prevention strategies may have limited effectiveness, if any. Thus, managing patients treated with BP may result in exposure of the practitioner to legal liability or malpractice claims: legal actions pursuant to BRONJ are reported to be underway on three continents. Nonetheless, the attribution of liability, if any, is a complex process requiring, on the basis of current knowledge, a robust and pragmatic approach to the facts, which must be identified from the point of view of the time, place and individuals involved. This means a comprehensive consideration of the sequence of actions from bisphosphonates prescription to BRONJ occurrence (as well as immediately after, and any action potentially related to its causation or worsening) is required in order to determine if a breach in informing, diagnosing, managing or referring the patient took place, as well as determining if the patient was compliant in attending to prescriptions and follow-up programmes.

Effect of low-level laser therapy on oral keratinocytes exposed to bisphosphonate

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a side effect of bisphosphonate therapy. However, its pathophysiology is not yet fully elucidated, and effective treatment of BRONJ remains unclear. The aim of this study is to investigate the effects of alendronate on oral keratinocytes and of low-level laser therapy (LLLT) on alendronate-treated keratinocytes, specifically by evaluating their viability, apoptosis, and wound healing function after irradiation. Oral keratinocyte cells (HaCaT) were exposed to 25 μM alendronate. Then, laser irradiation was performed with a low-level Ga-Al-As laser (λ = 808 ± 3 nm, 80 mW, and 80 mA; NDLux, Seoul, Korea) using 1.2 J/cm(2) energy dose. Viability was analyzed using MTT assay. Apoptosis was measured by Hoechst staining, caspase assay. Changes in secretion of IL-8, VEGF, and collagen type I were studied by ELISA and immunofluorescence microscopy. Scratch wound assays were also performed to measure cellular migration. Our results show that alendronate inhibits keratinocyte viability, expression of IL-8, VEGF, and collagen type I which are intimately related to healing events and cell migration while promoting apoptosis. Our results serve to demonstrate the utility of LLLT in partially overcoming the inhibitory effects of this bisphosphonate. From these results, the authors believe that the present study will provide an experimental basis for a fuller explanation of the clinical effects of LLLT as a BRONJ treatment modality.

Dental implications of bisphophonate-related osteonecrosis

OBJECTIVES

The aim is to explore the current theories about clinical , pathological and dental management of bisphosphonate related osteonecrosis of the jaws. Also discussed are the actions of bisphosphonates, pathogenesis related to the susceptibility of jaws, the predisposing risk factors for the development of bisphosphonate-related osteonecrosis of the jaws (BRONJ) and diagnostic criteria based on the literature review.

DISCUSSION

Osteoporosis is a disease that generally affects the mineral status of both cortical and trabecular bone in post menopausal women. Bisphosphonates are a group of drugs that preserve and increase bone mass. Bisphosphonate drugs are classified according to use and method of delivery. The bisphosphonates used for the treatment of osteoporosis are taken orally. Little is known about the side effects and dangers of the long-term use of therapeutic doses of Bisphosphonates. A recent complication reported is osteonecrosis of jaws. The use of IV bisphosphonates for multiple myeloma and metastatic bone diseases suggests that dosage, length of treatment, and route of administration, as well as cofactors such as use of glucocorticoids and immunosuppressive agents, and dental surgery, could all be related to the incidence of BRONJ. This review provides an update on current knowledge about clinical, pathological and management aspects of BRONJ.

CONCLUSIONS

Little evidence exists to direct the prosthodontic management of patients with a history of bisphosphonate use. Patients with active osteonecrosis related to bisphosphonate use have reduced tissue tolerance to function with removable prostheses and decreased potential for osseointegration of dental implants. Decisions should be based on clinical judgment tempered by the presenting conditions, medical profile, and patient needs. A better understanding would help in a dental setting to prevent any complication and help to improve the prognosis for those being treated for osteoradionecrosis.Until further evidence emerges regarding management of patients with active bisphosphonate- related osteonecrosis, conservative prosthodontic treatment is reasonable and prudent.

Risk factors for osteonecrosis of the jaws: a case-control study from the CONDOR dental PBRN

Case reports and cohort studies have linked bisphosphonate therapy and osteonecrosis of the jaws (ONJ), but neither causality nor specific risks for lesion development have been clearly established. We conducted a 1:3 case-control study with three dental Practice-based Research Networks, using dentist questionnaires and patient interviews for collection of data on bisphosphonate therapy, demographics, co-morbidities, and dental and medical treatments. Multivariable logistic regression analyses tested associations between bisphosphonate use and other risk factors with ONJ. We enrolled 191 ONJ cases and 573 controls in 119 dental practices. Bisphosphonate use was strongly associated with ONJ (odds ratios [OR] 299.5 {95%CI 70.0-1282.7} for intravenous [IV] use and OR = 12.2 {4.3-35.0} for oral use). Risk markers included local suppuration (OR = 7.8 {1.8-34.1}), dental extraction (OR = 7.6 {2.4-24.7}), and radiation therapy (OR = 24.1 {4.9-118.4}). When cancer patients (n = 143) were excluded, bisphosphonate use (OR = 7.2 {2.1-24.7}), suppuration (OR = 11.9 {2.0-69.5}), and extractions (OR = 6.6 {1.6-26.6}) remained associated with ONJ. Higher risk of ONJ began within 2 years of bisphosphonate initiation and increased four-fold after 2 years. Both IV and oral bisphosphonate use were strongly associated with ONJ. Duration of treatment > 2 years; suppuration and dental extractions were independent risk factors for ONJ.

Hematogenous spinal infection in central Greece

STUDY DESIGN

We retrospectively analyzed spinal infection (SpI), in a teaching Hospital, in Central Greece.

OBJECTIVE

To study presentation, etiology, and outcome of SpI in Central Greece.

SUMMARY OF BACKGROUND DATA

SpI most frequently involves the intervertebral disc and adjacent vertebral bodies and can cause neurologic impairment.

METHODS

Thirty three patients (23 men; age [mean +/- standard deviation], 60.6 +/- 11.3 years; disease duration, 44.5 [+/-54.7] days) hospitalized with SpI between January 2000 and December 2007 were included in the study. All patients had magnetic resonance imaging of the spine.

RESULTS

Nineteen patients had pyogenic SpI (57.6%) and 14 patients had granulomatous SpI, 11 due to Brucella spp (34.4%), 3 due to Mycobacterium tuberculosis (9.4%). Staphylococcus aureus was the most frequent cause of pyogenic SpI, and spondylodiscitis (SpD) was the most frequent localization. Epidural entension was found in 8 of 17 pyogenic SpD and in 2 of 11 brucellar SpD patients. Subdural extension was detected in 3 patients with pyogenic SpD. Blood cultures were positive in 17 of 19 patients with pyogenic SpI. Two patients had concomitant endocarditis (staphylococcal 1, enterococcal 1). The most common associated disease was diabetes mellitus. All but 2 patients received medical treatment alone. Two patients died of uncontrollable sepsis.

CONCLUSION

Back pain in presence of fever, constitutional symptoms, and/or high inflammation markers should alert physicians for spinal infection. In endemic areas, Brucella is a frequent cause of SpI.

Ibandronate: a review of its use in the management of postmenopausal osteoporosis

Ibandronate (ibandronic acid; Bonviva, Boniva), a nitrogen-containing bisphosphonate available in once-monthly oral and quarterly intravenous formulations for intermittent administration, has been approved for the treatment of osteoporosis in postmenopausal women in the EU, the US and many other countries worldwide. The once-monthly oral formulation has also been approved for the prevention of postmenopausal osteoporosis in the US. Ibandronate is an effective and generally well tolerated bisphosphonate that offers an alternative to other bisphosphonates as a first-line treatment for postmenopausal osteoporosis. It occupies a similar position with respect to the prevention of osteoporosis in postmenopausal women at risk for the disease. The once-monthly oral and quarterly intravenous dosage regimens have the potential to improve treatment adherence and persistence, and hence clinical outcomes, compared with more frequently administered oral bisphosphonates. Intravenous ibandronate may be particularly useful for postmenopausal osteoporotic women who are noncompliant with, or are unable to tolerate or receive, oral bisphosphonates. Thus, intermittent ibandronate extends the range of pharmacological therapies for the treatment and prevention of postmenopausal osteoporosis.

Oral nitrogen-containing bisphosphonates: a systematic review of randomized clinical trials and vertebral fractures

BACKGROUND

Vertebral fractures are the most common osteoporotic fracture. They are associated with increased morbidity and mortality, and also predict future vertebral and non-vertebral fracture risk. Bisphosphonates are the current mainstay for the treatment of postmenopausal osteoporosis. Health authority guidelines request that assessment of vertebral fracture risk reduction is part of the evaluation of bisphosphonate efficacy. In this review, we compare the published evidence for the efficacy of the nitrogen-containing oral bisphosphonates in reducing the risk of vertebral fractures.

METHODS

A review of publications in the treatment of postmenopausal osteoporosis and the most frequently prescribed oral bisphosphonate therapies (alendronate, ibandronate and risedronate) was carried out using the Dialog (Embase and Medline) and Cochrane online scientific citation databases. Eligible publications were those reporting randomized, placebo-controlled trials that included vertebral fracture as the primary or secondary endpoint (any time-point).

RESULTS

Of 159 publications identified, six studies assessing alendronate, ibandronate and risedronate met the pre-defined eligibility criteria. In total, 14,083 women were included in the studies, with 8182 patients receiving active treatment. Most studies were 3 years in duration. Discontinuation rates varied from 11 to 45%, being highest in those studies that specified one or more vertebral fracture as part of the inclusion criteria. Across these studies, the reduction in the risk of vertebral fractures ranged from 41 to 62% (44-48% for alendronate; 41-49% for risedronate; 62% for ibandronate).

CONCLUSIONS

Nitrogen-containing oral bisphosphonates effectively reduce the risk of osteoporotic vertebral fracture, with the magnitude of effect ranging from 41 to 62%.

An osteoclast-targeting agent for imaging and therapy of bone metastasis

A hybrid compound (DO3A-BP) featuring a radiometal bifunctional chelator (1,4,7,10-tetraazacyclotetradecane-N,N',N'',N'''-tetraacetic acid, DOTA) and an osteoclast-targeting moiety (bisphosphonate) was designed and synthesized. The (111)In-labeled complex of DO3A-BP showed significantly elevated uptake in osteoclasts compared to the undifferentiated adherent bone marrow derived cells. Biodistribution studies revealed a favorable tissue distribution profile in normal mice with high bone uptake and long retention, and low or negligible accumulation in non-target organs.

Bisphosphonate-related osteonecrosis of the jaws: an update on clinical, pathological and management aspects

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is mainly observed in patients with multiple myeloma and bone metastasis from solid tumors receiving iv bisphosphonate therapy. The reported incidence of BRONJ is significantly higher with the iv preparations zoledronic acid and pamidronate while the risk appears to be minimal for patients receiving oral bisphosphonates. Currently available published incidence data for BRONJ are based on retrospective studies and estimates of cumulative incidence range from 0.8 to 12%. The mandible is more commonly affected than the maxilla (2:1 ratio), and 60-70% of cases are preceded by a dental surgical procedure. The signs and symptoms that may occur before the appearance of clinical evident osteonecrosis include changes in the health of periodontal tissues, non-healing mucosal ulcers, loose teeth and unexplained soft-tissue infection. Although the definitive role of bisphosphonates remains to be elucidated, the inhibition of physiologic bone remodeling and angiogenesis by these potent drugs impairs the regenerative capacity of the bone causing the development of BRONJ. Tooth extraction as a precipitating event is a common observation. The significant benefits that bisphosphonates offer to patients clearly surpass the risk of potential side effects; however, any patient for whom prolonged bisphosphonate therapy is indicated, should be provided with preventive dental care in order to minimize the risk of developing this severe condition. This article provides an update review of current knowledge about clinical, pathological and management aspects of BRONJ.