Bone quality in zebrafish vertebrae improves after alendronate administration in a glucocorticoid-induced osteoporosis model

Glucocorticoid-induced osteoporosis (GIOP) changes the microarchitecture of bones and often leads to the reduction of bone-mineral density (BMD) and increased fracture rates. Zebrafish has been used as an alternative model for GIOP, however, the interaction of GIOP, and its treatment, with zebrafish bone morphometrics and mechanical properties, remains a challenge. Thus, this study aimed to evaluate the effects of prednisolone and alendronate on the properties of zebrafish vertebrae. Adult 7-month-old zebrafish were distributed into four groups: control (CTRL), prednisolone-only (PN), alendronate-only (ALN), and the sequential use of both medicines (PN + ALN). Fish skeletons were scanned via micro-tomography (n = 3) to obtain vertebra morphometrics (e.g., BMD). Bone morphology was assessed using scanning electron microscopy (n = 4) and the biomechanical behaviour with nanoindentation technique (n = 3). The BMD decreased in PN (426.08 ± 18.58 mg/cm3) and ALN (398.23 ± 10.20 mg/cm3) groups compared to the CTRL (490.43 ± 41.96 mg/cm3) (p < 0.001); however, administering the medicines in sequence recovered the values to healthy levels (495.43 ± 22.06 mg/cm3) (p > 0.05). The bone layered structures remain preserved in all groups. The vertebrae of the groups that received ALN and PN + ALN, displayed higher modulus of elasticity (27.27 ± 1.59 GPa and 25.68 ± 2.07 GPa, respectively) than the CTRL (22.74 ± 1.60 GP) (p < 0.001). ALN alone increased the hardness of zebrafish vertebrae to the highest value among the treatments (1.32 ± 0.13 GPa) (p < 0.001). Conversely, PN + ALN (1.25 ± 0.11 GPa) showed unaltered hardness from the CTRL (1.18 ± 0.13 GPa), but significantly higher than the PN group (1.08 ± 0.12 GPa) (p < 0.001). ALN administered after GIOP development, rescued osteoporotic condition by recovering the BMD and bone hardness in zebrafish vertebrae.

Alendronate-Functionalized Graphene Quantum Dots as an Effective Fluorescent Sensing Platform for Arsenic Ion Detection

Alendronate-functionalized graphene quantum dots (ALEN-GQDs) with a quantum yield of 57% were synthesized via a two-step route: preparation of graphene quantum dots (GQDs) by pyrolysis method using citric acid as the carbon source and post functionalization of GQDs via a hydrothermal method with alendronate sodium. After careful characterization of the obtained ALEN-GQDs, they were successfully employed as sensing materials with superior selectivity and sensitivity for the detection of nanomolar levels of arsenic ions (As(III)). According to the mechanistic investigation, arsenic ions can quench the fluorescence intensity of ALEN-GQDs through metal-ligand interaction between the As(III) ions and the surface functional groups of the fluorescent probe. This probe provided a rapid method to monitor As(III) with a wide detection range (44 nM-1.30 µM) and a low detection limit of 13 nM. Finally, to validate the applicability, this novel fluorescent probe was successfully applied for the quantitative determination of As(III) in rice and water samples.

Unravelling pH/pKa influence on pH-responsive drug carriers: Insights from ibuprofen-silica interactions and comparative analysis with carbon nanotubes, sulfasalazine, and alendronate

This study employs density functional theory to explore the interaction between ibuprofen (IBU) and silica, emphasizing the influence of the trimethylsilyl (TMS) functional group for designing pH-responsive drug carriers. The surface (S) and drug (D) molecules' neutral (0) or deprotonated (-1) states were taken into consideration during the investigation. The likelihood of these states was determined based on the pKa values and the desired pH conditions. To calculate the pH-dependent interaction energy (EintpH), four different situations have been identified: S0D0, S0D-1, S-1D0, and S-1D-1.The electrostatic component of interaction energy aligns favorably with its theoretical value in both the Debye-Hückel and Grahame models. The investigation has gathered first-hand experimental data on the drug loading and release of pH-responsive mesoporous silica nanoparticles. Effective drug loading was observed in the acidic environment of the stomach (pH 2-5), followed by a release in the slightly basic to neutral pH of the small intestine (pH 7.4), These findings align with existing literature. The results revealed horizontal drug adherence on silica surfaces, improving binding capabilities. Comparisons were made with combinations involving carboxylated carbon nanotubes and ibuprofen, silica, and sulfasalazine, and silica and alendronate, exploring drug loading/release dynamics associated with positive/negative interaction energies. The investigation, supported by experimental data, contributes valuable insights into pH-responsive mesoporous silica nanoparticles, offering new design possibilities for drug carriers.

Bisphosphonate alternative regimens for the prevention of osteoporotic fragility fractures: BLAST-OFF, a mixed-methods study

Background

Bisphosphonates are a class of medication commonly used to treat osteoporosis. Alendronate is recommended as the first-line treatment; however, long-term adherence (both treatment compliance and persistence) is poor. Alternative bisphosphonates are available, which can be given intravenously and have been shown to improve long-term adherence. However, the most clinically effective and cost-effective alternative bisphosphonate regimen remains unclear. What is the most cost-effective bisphosphonate in clinical trials may not be the most cost-effective or acceptable to patients in everyday clinical practice.

Objectives

1. Explore patient, clinician and stakeholder views, experiences and preferences of alendronate compared to alternative bisphosphonates. 2. Update and refine the 2016 systematic review and cost-effectiveness analysis of bisphosphonates, and estimate the value of further research into their benefits. 3. Undertake stakeholder/consensus engagement to identify important research questions and further rank research priorities.

Methods

The study was conducted in two stages, stages 1A and 1B in parallel, followed by stage 2: • Stage 1A - we elicited patient and healthcare experiences to understand their preferences of bisphosphonates for the treatment of osteoporosis. This was undertaken by performing a systematic review and framework synthesis of qualitative studies, followed by semistructured qualitative interviews with participants. • Stage 1B - we updated and expanded the existing Health Technology Assessment systematic review and clinical and cost-effectiveness model, incorporating a more comprehensive review of treatment efficacy, safety, side effects, compliance and long-term persistence. • Stage 2 - we identified and ranked further research questions that need to be answered about the effectiveness and acceptability of bisphosphonates.

Results

Patients and healthcare professionals identified a number of challenges in adhering to bisphosphonate medication, balancing the potential for long-term risk reduction against the work involved in adhering to oral alendronate. Intravenous zoledronate treatment was generally more acceptable, with such regimens perceived to be more straightforward to engage in, although a portion of patients taking alendronate were satisfied with their current treatment. Intravenous zoledronate was found to be the most effective, with higher adherence rates compared to the other bisphosphonates, for reducing the risk of fragility fracture. However, oral bisphosphonates are more cost-effective than intravenous zoledronate due to the high cost of zoledronate administration in hospital. The importance of including patients and healthcare professionals when setting research priorities is recognised. Important areas for research were related to patient factors influencing treatment selection and effectiveness, how to optimise long-term care and the cost-effectiveness of delivering zoledronate in an alternative, non-hospital setting.

Conclusions

Intravenous zoledronate treatment was generally more acceptable to patients and found to be the most effective bisphosphonate and with greater adherence; however, the cost-effectiveness relative to oral alendronate is limited by its higher zoledronate hospital administration costs.

Future work

Further research is needed to support people to make decisions influencing treatment selection, effectiveness and optimal long-term care, together with the clinical and cost-effectiveness of intravenous zoledronate administered in a non-hospital (community) setting.

Limitations

Lack of clarity and limitations in the many studies included in the systematic review may have under-interpreted some of the findings relating to effects of bisphosphonates.

Trial registration

This trial is registered as ISRCTN10491361.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127550) and is published in full in Health Technology Assessment; Vol. 28, No. 21. See the NIHR Funding and Awards website for further award information.

A Dual Reversible Cross-Linked Hydrogel with Enhanced Mechanical Property and Capable of Proangiogenic and Osteogenic Activities for Bone Defect Repair

The clinical treatment of bone defects presents ongoing challenges. One promising approach is bone tissue engineering (BTE), wherein hydrogels have garnered significant attention. However, the application of hydrogels in BTE is severely limited due to their poor mechanical properties, as well as their inferior proangiogenic and osteogenic activities. To address these limitations, our develop a dual cross-linked alendronate (ALN)-Ca2+ /Mg2+ -doped sulfated hyaluronic acid (SHA@CM) hydrogel, using a one-step mixing injection molding method known as "three-in-one" approach. This approach enabled the simultaneous formation of Schiff-Base crosslinking and electric attraction-based crosslinking within the hydrogel. The Schiff-Base crosslinking contributed to the majority of the hydrogel's mechanical strength, while the electric attraction-based crosslinking served as a release reservoir for Ca2+ /Mg2+ and ALN, promoting enhanced osteogenic activities and providing additional mechanical reinforcement to the hydrogel. These experimental data demonstrates several favorable properties of the SHA@CM hydrogel, including satisfactory injectability, rapid gelation, self-healing capacity, and excellent cytocompatibility. Moreover, the presence of sulfated groups and Mg2+ within the SHA@CM hydrogel exhibited pro-angiogenic effects, while the controlled release of nanoparticles formed by Ca2+ /Mg2+ and ALN further enhanced the osteogenesis of the hydrogel. Overall, these results indicate that the SHA@CM hydrogel holds significant potential for the clinical translation of BTE.

Ca-AlN MOFs-loaded chitosan/gelatin scaffolds; a dual-delivery system for bone tissue engineering applications

Creating a scaffold for bone tissue engineering that is bioactive and capable of acting as a local-dual delivery system, releasing bioactive molecules and regulating the bone remodeling process to achieve balanced bone resorption and formation, is a significant challenge. The objective of this research is to create a composite scaffold using chitosan/gelatin (CHS/Gel) and the calcium (Ca)-alendronate (ALN) metal-organic frameworks (MOFs). The scaffold will act as a dual-delivery system, releasing Ca ions and ALN to regulate bone formation. Ca-ALN MOF nanoparticles (NPs) were prepared in mild conditions and studied by FTIR, XRD, FESEM, and TGA. Ca-ALN NPs-loaded CHS/Gel scaffolds were opportunely fabricated through freeze-drying approach. Physicochemical features of the scaffolds after incorporating NPs equated by CHS/Gel scaffold changed, therefore, the attendance of NPs caused a decreasing porosity, decreased swelling, and low rate of degradation. The release profile results showed that the NPs-loaded CHS/Gel scaffolds were able to simultaneously release ALN and Ca ions due to the decomposition of NPs. Additionally, the loading of NPs in the CHS/Gel scaffold led to an increment in alkaline phosphatase (ALP) activity and the quantity of deposited Ca along with osteogenesis gene markers. These findings suggest that the NPs-loaded CHS/Gel scaffold has the potential to enhance the differentiation of human adipose tissue-derived mesenchymal stem cells, making it a promising approach for bone repair.

High throughput analysis of alendronate in human samples with derivatization-free hydrophilic-interactive chromatography mass spectrometry

A derivatization-free hydrophilic-interactive chromatography-mass spectrometry (HILIC-MS/MS) method was developed for quantifying low levels of alendronate in human plasma. Alendronate was separated and concentrated using calcium co-precipitation and analyzed by HILIC-MS/MS, requiring only a 300 μL plasma sample for each analysis. The method is simpler, safer, and more environmentally friendly than the conventional LC-MS/MS method that requires solid-phase extraction and derivatization steps during sample pretreatment. The method was validated for selectivity, linearity, precision, accuracy, extraction recovery, matrix effect and limit of quantification. The between-run precisions were no more than 7.1 % with accuracy ranging from - 1.7-6.3 %; extraction recovery was determined to be 85.3 %; while validation results indicated that the method was suitable for accurately quantifying alendronate concentrations in the range from 0.2 to 50 ng/mL. The approach was used successfully for high throughput analysis of alendronate in more than 3700 plasma samples from 120 subjects in a bioequivalence study.

Theoretical insights and implications of pH-dependent drug delivery systems using silica and carbon nanotube

In this paper we have studied the density functional theory of four drugs ibuprofen, alendronate, Sulfasalazine and paracetamol with quartz, propylamine, trimethylamine functionalized quartz and carboxyl modified carbon nanotube. The attractive and repulsive interaction energies between drugs and quartz is obtained at various pH values. The attractive and repulsive energies are well correlated with experimental drug loading and releasing behavior by mesoporous silica nanoparticles. Further, a theoretical model is developed that accounts the electrostatic interaction between silica and drug and the model can predict the drug loading and releasing behavior by silica nanoparticles at various pH values. Sulfasalazine can be taken orally and loaded with trimethyl ammonium functionalized mesoporous silica nanoparticles, which keeps the drug in tact with the carrier in the acidic environment of the stomach and releases it into the neutral or basic medium of the small intestine. Alendronate may be loaded and released from propylamine functionalized mesoporous silica nanoparticles in the ranges of 1-5 and > 8, respectively. Ibuprofen is absorbed in an acidic environment and released in basic conditions for carboxyl modified carbon nanotube. The loading and releasing pH ranges for paracetamol in trimethylammonium functionalized mesoporous silica nanoparticles are 4-8 and >8, respectively. We also convert the pH-dependent variant of the diffusion-controlled Higuchi equation. We have changed the original Higuchi equation to produce the pH-dependent variation by incorporating the Nernst-Planck equation into Flick's first law. The updated equation could be used to forecast when medication particles with varying release times will emerge from a nanoparticles matrix.

Long-term consequences of osteoporosis therapy with bisphosphonates

Bisphosphonates (BPs) are medications widely used in clinical practice to treat osteoporosis and reduce fragility fractures. Its beneficial effects on bone tissue have been consolidated in the literature for the last decades. They have a high affinity for bone hydroxyapatite crystals, and most bisphosphonates remain on the bone surface for a long period of time. Benefits of long-term use of BPs: Large and important trials (Fracture Intervention Trial Long-term Extension and Health Outcomes and Reduced Incidence with Zoledronic acid Once Yearly-Pivotal Fracture Trial) with extended use of alendronate (up to 10 years) and zoledronate (up to 6 years) evidenced significant gain of bone mineral density (BMD) and vertebral fracture risk reduction. Risks of long-term use of BPs: The extended use of antiresorptive therapy has drawn attention to two extremely rare, although severe, adverse events. That is, atypical femoral fracture and medication-related osteonecrosis of the jaw are more common in patients with high cumulative doses and longer duration of therapy. BPs have demonstrated safety and effectiveness throughout the years and evidenced increased BMD and reduced fracture risks, resulting in reduced morbimortality, and improved quality of life. These benefits overweight the risks of rare adverse events.

Osteophilic and Dual-Regulated Alendronate-Gene Lipoplexes for Reversing Bone Loss

The pathogenesis of postmenopausal osteoporosis (PMOP) is mainly determined by the adhesion of osteoclasts to the bone matrix and the involvement of various molecules in bone resorption. The dual regulation strategy of the physical barriers of bone matrix and intracellular gene regulation generated by advanced biomaterials is a decent alternative for the treatment of PMOP. Herein, for the first time, it is identified that hsa-miR-378i/mmu-miR-378a-3p are closely associated with PMOP. Then, an osteophilic and dual-regulated alendronate-gene lipoplex (antagomir@Aln-Lipo), composed of medicative alendronate-functionalized liposomal vehicle and encapsulated specific microRNAs is engineered, for bone-targeting delivery of genes to achieve combined mitigation of bone loss. Alendronate targets hydroxyapatite in the bone matrix and occupies the adhesion site of osteoclasts, thus providing the "physical barriers". Antagomir is coupled precisely to specific endogenous microRNAs, thus providing the "genetic signals". These functionalized lipoplexes exhibited long-term stability and good transfection efficiency. It is proven that antagomir@Aln-Lipo could synergistically regulate osteoclastogenesis and bone resorption in vitro and in vivo. Furthermore, intravenous injection of antagomir@Aln-Lipo efficiently reverses bone loss through a dual mechanism driven by alendronate and antagomir-378a-3p. In conclusion, the osteophilic and dual-regulated antagomir@Aln-Lipo offers a brand-new bifunctional strategy for the precise treatment of PMOP.

Technetium-99m labeled core shell hyaluronate nanoparticles as tumor responsive, metastatic skeletal lesion targeted combinatorial theranostics

Achieving target specific delivery of chemotherapeutics in metastatic skeletal lesions remains a major challenge. Towards this, a dual drug loaded, radiolabeled multi-trigger responsive nanoparticles having partially oxidized hyaluronate (HADA) conjugated to alendronate shell and palmitic acid core were developed. While the hydrophobic drug, celecoxib was encapsulated in the palmitic acid core, the hydrophilic drug, doxorubicin hydrochloride was linked to the shell via a pH responsive imine linkage. Hydroxyapatite binding studies showed affinity of alendronate conjugated HADA nanoparticles to bones. Enhanced cellular uptake of the nanoparticles was achieved via HADA-CD44 receptor binding. HADA nanoparticles demonstrated trigger responsive release of encapsulated drugs in the presence of hyaluronidase, pH and glucose, present in excess in the tumor microenvironment. Efficacy of the nanoparticles for combination chemotherapy was established by >10-fold reduction in IC₅₀ of drug loaded particles with a combination index of 0.453, as compared to free drugs in MDA-MB-231 cells. The nanoparticles could be radiolabeled with the gamma emitting radioisotope technetium-99m (^99mTc) through a simple, 'chelator free', procedure with excellent radiochemical purity (RCP) (>90 %) and in vitro stability. ^99mTc-labeled drug loaded nanoparticles reported herein constitutes a promising theranostic agent to target metastatic bone lesions. STATEMENT OF HYPOTHESES: Technetium-99m labeled, alendronate conjugated, dual targeting, tumor responsive, hyaluronate nanoparticle for tumor specific drug release and enhanced therapeutic effect, with real-time in vivo monitoring.

Acidity-Triggered Transformable Polypeptide Self-Assembly to Initiate Tumor-Specific Biomineralization

Biomineralization is a normal physiological process that includes nucleation, crystal growth, phase transformation, and orientation evolution. Notably, artificially induced biomineralization in the tumor tissue has emerged as an unconventional yet promising modality for malignancy therapy. However, the modest ion-chelating capabilities of carboxyl-containing biomineralization initiators lead to a deficient blockade, thus compromising antitumor efficacy. Herein, a biomineralization-inducing nanoparticle (BINP) is developed for blockade therapy of osteosarcoma. BINP is composed of dodecylamine-poly((γ-dodecyl-l-glutamate)-co-(l-histidine))-block-poly(l-glutamate-graft-alendronate) and combines a cytomembrane-insertion moiety, a tumor-microenvironment (TME)-responsive component, and an ion-chelating motif. After intravenous injection into osteosarcoma-bearing mice, BINP responds to the acidic TME to expose the dodecyl group on the surface of the expanded nanoparticles, facilitating their cytomembrane insertion. Subsequently, the protruding bisphosphonic acid group triggers continuous ion deposition to construct a mineralized barrier around the tumor, which blocks substance exchange between the tumor and surrounding normal tissues. The BINP-mediated blockade therapy displays tumor inhibition rates of 59.3% and 52.1% for subcutaneous and orthotopic osteosarcomas, respectively, compared with the Control group. In addition, the suppression of osteoclasts by the alendronate moiety alleviates bone dissolution and further inhibits pulmonary metastases. Hence, the BINP-initiated selective biomineralization provides a promising alternative for clinical osteosarcoma therapy.

Bone loss after denosumab discontinuation is prevented by alendronate and zoledronic acid but not risedronate: a retrospective study

A retrospective study of 121 patients who stopped denosumab (Dmab) then received no treatment (NT), risedronate (RIS), alendronate (ALN), or zoledronic acid (ZOL). Bone density (spine and hip) during and after Dmab discontinuation was measured. Treatment with ALN or ZOL, not NT and RIS, mitigated BMD loss after Dmab discontinuation.

INTRODUCTION

Denosumab (Dmab) discontinuation is associated with bone loss and multiple vertebral fractures. The purpose was to compare bone mineral density (BMD) change in patients following Dmab discontinuation with no subsequent treatment (NT) and three bisphosphonate (BP) treatments: risedronate (RIS), alendronate (ALN), and zoledronic acid (ZOL).

METHODS

In a review of 121 patients aged 71.2 ± 8.1 years, discontinuing Dmab (mean 5.4 doses), 33 received NT and 88 received BP (22 RIS; 34 ALN; 32 ZOL). BMD change after 1 year was compared between groups at the lumbar spine (LS), femoral neck (FN), and total hip (TH). Risk factors for bone loss after Dmab discontinuation were compared between groups and incidence of vertebral fractures was determined.

RESULTS

Following Dmab discontinuation, LS mean change (g/cm2; 95% CI) was for NT: - 0.041 (- 0.062 to - 0.021); RIS: - 0.035 (- 0.052 to - 0.017); ALN: - 0.005 (- 0.020 to 0.009); and ZOL: - 0.009 (- 0.025 to 0.008). Differences in LS were found between NT and ALN (p =  0.015), and NT and ZOL (p=0.037), but not between NT and RIS. The only significant difference in TH was found between NT and ZOL (p 0.034) with no group differences in FN. BMD gains during Dmab treatment were associated with BMD loss after Dmab discontinuation. In a subset, discontinuation after Dmab treatment (> 5 doses) followed by ALN (n = 22) and ZOL (n = 11) showed no difference in BMD. Five of 7 vertebral fractures occurred after Dmab discontinuation in NT.

CONCLUSION

Subsequent treatment with ALN or ZOL but not NT and RIS mitigates BMD loss after Dmab discontinuation.

NH2-MIL-101(Fe) nanozyme-based dual-modality sensor for determination of alendronate sodium and study of two-dimensional correlation spectroscopy

We developed a dual-modality sensing platform for ratiometric fluorescence and colorimetric determination of alendronate sodium (ALDS). This platform was performed by using a NH₂- MIL-101(Fe) as a peroxidase mimic. Since preferential complexing between Fe³⁺ (active site for peroxidase) and ALDS, the production of 2,3-diaminophenazine (DAP, oxidized product of OPD) has been inhibited in the presence of H₂O₂. As a result, the ratiometric fluorescence value of F₅₅₆/F₄₅₆ and absorbance at 450 nm exhibited significant changes, which could be used as the dual-modality sensing platform. In addition, Two-dimensional correlation spectroscopy (2D-COS) analysis on Fourier-transform infrared (FTIR), ultraviolet visible and ratiometric fluorescence spectra were applied to investigate the binding features. Synchronous and asynchronous maps of these spectra confirmed our above hypothesis, in which Fe³⁺-ALDS complex was the critical factor that regulated dual-modality signals. To our knowledge, the 2D-COS method was applied to study the catalytic and sensing mechanism of nanozyme as NH₂- MIL-101(Fe) for the first time. This technique was helpful to understand interaction of substrates on nanozyme and develop more sensitive sensors for assaying.

Modified Alendronate Mitigates Mechanical Degradation of the Rotator Cuff in an Osteoporotic Ovine Model

BACKGROUND

Osteoporosis is an independent risk factor for failure after arthroscopic rotator cuff repair. Since rerupture rates after rotator cuff repair are associated with decreased bone mineral density and bone microarchitecture, adaptations of biomechanical properties of the rotator cuff enthesis in patients with osteoporosis remain unclear. Additionally, the effects of osteogenic therapy carrier drugs used for the treatment of osteoporosis on rotator cuff structure and properties have not been previously documented.

PURPOSE

To investigate the changes to soft tissue biomechanics and insertional structure secondary to osteoporosis with and without an osteogenic therapy carrier (ie, modified alendronate).

STUDY DESIGN

Controlled laboratory study.

METHODS

Biomechanical, histopathological, and microcomputed tomography analyses were performed on 20 shoulders obtained from 10 osteoporotic sheep randomly allocated to modified bisphosphonate (ie, alendronate) or control (ie, osteoporotic without treatment) groups; 6 shoulders from healthy sheep were utilized for comparison purposes.

RESULTS

Tendons from the control group exhibited a 57% decrease in undeformed Young modulus as compared with the healthy group (P = .010). Tendons from the modified bisphosphonate treatment group exhibited a 229% increase in initial Young modulus as compared with the control group (P = .010). Marked changes within the tendon insertional organization were noted in both the control and the modified bisphosphonate treatment group samples as evidenced by increased interdigitation of the bone-mineralized fibrocartilaginous junction. The control samples exhibited a markedly paucicellular insertion, whereas the modified bisphosphonate treated tendons exhibited a hypercellular insertional region as compared with the healthy group. Both groups exhibited significantly (P < .01) decreased bone quality underlying the infraspinatus insertion, as evidenced by all microcomputed tomography outcome parameters.

CONCLUSION

This work illuminates changes to rotator cuff tendon secondary to osteoporosis. Specifically, it revealed decreased tendon modulus and altered insertional structure in the osteoporotic samples. Secondarily, these data revealed increases in tendon modulus accompanied by increased cellularity within the tendon insertion region after systemic modified bisphosphonate injections.

CLINICAL RELEVANCE

Bisphosphonate treatment may have a positive effect on the healing of the enthesis after rotator cuff repair.

Engineering Alendronate-Composed Iron Nanochelator for Efficient Peritoneal Carcinomatosis Treatment

Iron is an essential element for various cellular metabolism. Cancer cells also have high requirement of iron in their proliferation, invasion, and metastasis processes. Alendronate (ALN), a kind of FDA-approved bisphosphonates with metal-chelating capability, is initially certified to selectively bind to intracellular Fe³⁺ theoretically and experimentally in this study. Hence, CaALN iron nanochelator is rationally designed to kill cancer cells by synergism of Fe-depletion and calcium accumulation. In vitro experiments and RNA sequencing analysis indicate that CaALN nanomedicine inhibits the proliferation of cancer cells by depleting Fe, interfering with DNA replication, and triggering intracellular reactive oxygen species (ROS). Meanwhile, released Ca²⁺ and ROS mutually promote and induce damage of cellular macromolecules, which leads to mitochondrial apoptosis of cancer cells. In an intraperitoneal disseminated mouse model with the human ovarian cancer cells SKOV3, CaALN nanoparticles selectively accumulate in tumor tissues and result in significant retardation of tumor growth and ascites formation. The mean survival time of SKOV3-bearing mice in treatment group is prolonged from 33 to 90 d. These results indicate that the alendronate-originated iron chelator can serve as an efficient strategy for the treatment of peritoneal carcinomatosis.

Bone healing study of alendronate combined with enoxaparin sodium bone cement in rabbits with bone defects

BACKGROUND

To observe the effect of enoxaparin sodium-polymethyl methacrylate (ES-PMMA) bone cement supplemented with alendronate (AN) on bone repair of bone defects in New Zealand rabbits.

METHODS

Twenty-seven New Zealand rabbits were randomly divided into ES/AN, ES-PMMA and PMMA groups, with a total of 27 New Zealand rabbits. The drugs loaded in 40 g bone cement powder were as follows: ES/AN group 8000 AxaIU enoxaparin (ES) and 200 mg alendronate (AN), ES-PMMA group 8000 AxaIU enoxaparin (ES), PMMA group without drugs. A bone defect model with a length of 10 mm and a diameter of 5 mm was made from the left tibia of rabbits, and the prepared bone cement was placed in the tibia defect. At 4 weeks, 8 weeks and 12 weeks after the operation, 3 rabbits in each group were sacrificed, and left tibia samples were collected for histological scoring, HE staining and Masson staining. Bone mineral density and new bone volume were measured by imaging, and the related data were processed by one-way ANOVA and least significance difference (LSD) post hoc test.

RESULTS

(1) Bone mineral density (BMD, mg/mm3) around the bone defect: at the 4th week, BMD in the ES/AN group was higher than that in the PMMA group; at the 8th week, the BMD in the ES/AN group was significantly higher than that in the other two groups; and at the 12th week, the BMD in the ES/AN group was significantly higher than that in the other two groups. (2) New bone volume (BV, mm3): at the 4th week, BV in the ES/AN group was significantly higher than that in the other two groups, BV in the ES/AN group was significantly higher than that in the other two groups at the 8th and 12th weeks, and BV in the ES-PMMA group was higher than that in the PMMA group. (3) Histological score: at the 4th and 8th weeks, the histological score of the ES/AN group was higher than that of the PMMA group, and at the 12th week, the histological score of the ES/AN group was higher than that of the other two groups. (4) Cortical bone thickness (μm): at the 4th, 8th and 12th weeks, the cortical bone thickness in the ES/AN group was higher than that in the other two groups, and the cortical bone thickness in the ES-PMMA group was higher than that in the PMMA group. (5) The percentage of mature area of new bone in the ES/AN group was higher than that in the other two groups at the 4th week, and at the 8th and 12th weeks, the percentage of mature area of new bone in the ES/AN group and ES-PMMA group was significantly higher than that in the PMMA group.

CONCLUSION

(1) Enoxaparin sodium bone cement supplemented with alendronate was superior to enoxaparin sodium bone cement and PMMA bone cement in promoting bone repair of tibial bone defects in New Zealand rabbits. (2) Enoxaparin sodium bone cement is superior to PMMA bone cement in promoting bone repair, showing a certain osteogenic potential.

Development of local injectable, bone-targeting nanocarriers of triptolide for treatment of bone-only metastasis

Triptolide (TP) is known for its diverse pharmacological activities but also its delivery and toxicity issues. This study aimed at exploiting TP's anticancer effects at lower risk of systemic toxicity by developing local-injectable "bone-targeting TP nanoparticle" (TPN) for bone-only metastasis treatment. The lipid/oil-based TPNs decorated with alendronate (ALE) achieved size of 70.4-111.2 nm with good dispersion stability. The drug encapsulation efficiency reached 97 % and drug release profiles were in biphasic, controlled manner lasting for 5 days in medium with serum proteins and calcium. TPNs were more cytotoxic than free TP against MDA-MB-231 breast cancer cells (IC50: 16.40 ± 0.80 nM vs 25.45 ± 1.83 nM, P < 0.05) but less cytotoxic against MC3T3-E1 osteoblasts (P < 0.05). When combined with paclitaxel or docetaxel, low dose TPN (containing 10 nM) significantly increased the effectiveness of the two chemotherapy drugs against MDA-MB-231 (IC50 values decreased from 7.3 nM to 2.5 nM for docetaxel; from 4.6 nM to 1.1 nM), indicating potent chemosensitization effects. Retardation of in vitro cancer cell migration by TPN was also observed in the standard scratch assay. ALE decoration significantly enhanced the TPN affinity for both calcium hydroxyapatite and porcine bone chip models, which led to enhancement in TP retention in the bones up to 8.1-fold versus free drug. Overall, TPN demonstrated good potential as a local-injectable, bone-targeted nanotherapy tailored for eradication of bone-only metastasis at reduced risk of systemic toxicity.

Preparation and evaluation of alendronate sodium solid lipid nanoparticles with high oral bioavailability in rats

Low oral bioavailability of alendronate sodium (ALE) significantly limits its clinical application. However, few studies focus on preparing ALE solid lipid nanoparticles (ALE-SLNs) and investigating its oral bioavailability in vivo due to highly hydrophilic property of ALE. In this study, ALE-SLNs were prepared through high-speed shearing combined with ultrasonic treatment method. ALE-SLNs were evaluated by average particle size, electric potential, encapsulation efficiency (EE), and drug loading (DL). Our results showed that the average EE and DL reached 62.56±0.94% and 6.26±0.09% (n=3), respectively. 120.27±1.17nm, 0.29±0.13 and -19.1±0.27 mV (n=3) were obtained in the average particle size, polydispersity index and zeta potential, respectively. The stability test showed that ALE-SLNs remained stable for more than 2 months at 4°C. After oral administration of ALE-SLNs (4.5mg/kg), the bioavailability was 2.17 times higher than that of ALE solution (86.82±3.6 vs 40.1±1.3μg) in rats. Our results indicate that high-speed shearing combined with the ultrasound method is simple and rapid to prepare ALE-SLNs. SLNs can improve the oral delivery of ALE in rats, which may exert beneficial effects in clinical applications.

Fracture rates and economic outcomes in patients with osteoporosis prescribed risedronate gastro-resistant versus other oral bisphosphonates: a claims data analysis

Patients with osteoporosis prescribed risedronate gastro-resistant had a lower incidence of fractures versus those prescribed other oral bisphosphonates. Administration of risedronate gastric-resistant does not require fasting, and this more convenient dosing administration may explain its improved efficacy.

PURPOSE

Up to half of patients do not follow complex dosing instructions of immediate-release bisphosphonates used for the prevention of osteoporotic fractures, which can result in suboptimal effectiveness. Risedronate gastro-resistant (GR) offers a more convenient dosing option by eliminating the need for fasting. This study compares fracture rates and outcomes between osteoporosis women treated with risedronate GR (GR cohort) versus other oral bisphosphonates (other cohort).

METHODS

Claims from women with osteoporosis in the USA were analyzed. Patients were classified into the two cohorts based on the first oral bisphosphonate observed (index date) and matched 1:1 based on patient characteristics. Patients were observed for ≥ 2 years following the index date. Fracture rates, health care resource utilization and costs, and treatment persistence were compared.

RESULTS

In total, 2,726 patients were selected in each cohort (median age: 60.0 years). The incidence of fractures was lower in the GR versus the other cohort for any fracture sites (incidence rate ratio, 95% CI: 0.83, 0.70-0.97) and spine fractures (0.71, 0.54-0.95), although the respective rate of medication discontinuation at 2 years was 80.5% and 74.4%. Time to first fracture was delayed for the GR cohort, reaching statistical significance after 36 months. The GR cohort incurred fewer hospitalizations (incidence rate per 1,000 patient-years: GR = 106.74; other = 124.20, p < 0.05) translating into lower hospitalization costs per patient per year (GR = $3,611; other = $4,603, p < 0.05).

CONCLUSIONS

Patients prescribed risedronate GR versus other bisphosphonates had a lower incidence of fractures, which may be explained by the fact that the GR formulation is absorbed even when taken with food.

A Phage Display-Identified Short Peptide Capable of Hydrolyzing Calcium Pyrophosphate Crystals-The Etiological Factor of Chondrocalcinosis

Chondrocalcinosis is a metabolic disease caused by the presence of calcium pyrophosphate dihydrate crystals in the synovial fluid. The goal of our endeavor was to find out whether short peptides could be used as a dissolving factor for such crystals. In order to identify peptides able to dissolve crystals of calcium pyrophosphate, we screened through a random library of peptides using a phage display. The first screening was designed to select phages able to bind the acidic part of alendronic acid (pyrophosphate analog). The second was a catalytic assay in the presence of crystals. The best-performing peptides were subsequently chemically synthesized and rechecked for catalytic properties. One peptide, named R25, turned out to possess some hydrolytic activity toward crystals. Its catalysis is Mg²⁺-dependent and also works against soluble species of pyrophosphate.

The predictive value of bone turnover markers during discontinuation of alendronate: the PROSA study

In patients discontinuing ALN after a median of 7.0 years (range 5.0-20.0 years), BMD decreased, and bone turnover markers increased within the premenopausal reference range over 2 years. Increased p-CTX after 3 months was associated with greater bone loss at the hip confirming that maintenance of BMD is dependent on continued suppression of bone turnover.

INTRODUCTION

It is unknown how to monitor patients discontinuing alendronate (ALN) after more than 5 years. We investigated if BTM measured before or during treatment discontinuation with ALN predict bone loss after 1 or 2 years.

METHODS

PROSA was a cohort study conducted at Aarhus University Hospital including postmenopausal women and men above 50 years treated with ALN ≥ 5 years who had osteopenia at the hip and BMD T-score at the lumbar spine > - 4. ALN was discontinued and BTMs were measured at baseline, months (M) 1, 3, 6, and 12, and DXA was performed at baseline, M6, and M12. We extended the study and measured BTMs and performed DXA at M24. The primary endpoint was if changes in p-CTX at M3 or M6 predict changes in THBMD after 1 year ( Clinicaltrials.gov : NCT03051620).

RESULTS

We enrolled 136 participants discontinuing ALN after a median of 7.0 years (range 5.0-20.0 years) in PROSA and 124 participants in PROSA Extension. There was a significant decrease in LSBMD - 0.74% ± 0.27, THBMD - 2.65% ± 0.39, FNBMD - 2.35% ± 0.33, and trabecular bone score - 0.97% ± 0.35 and an increase in p-CTX by 61.1% ± 4.7 (p < 0.05 for all) after 24 months. Increase in p-CTX at M3 was associated with bone loss at the hip sites at M12 and M24.

CONCLUSION

In patients discontinuing ALN, BMD decreased significantly and BTMs increased within the reference range over 2 years. An increase in p-CTX after 3 months was associated with greater bone loss at the hip confirming that maintenance of BMD during treatment discontinuation is dependent on continued suppression of bone turnover.

Alendronate/dexamethasone combination therapy worsens soft and hard tissue wound healing around implants in rat maxillae

Dental implant treatment in patients prescribed medications is associated with bisphosphonate-related osteonecrosis of the jaw (BRONJ) around the implants. However, there is no scientific information on how bisphosphonate and/or steroid therapies affect wound healing around implants after implant placement. The aim of this study was to histopathologically and immunopathologically investigate the effects of bisphosphonate and/or steroid therapy on the early stages of soft and hard tissue wound healing around implants in rat maxillae. Eight-week-old female Wistar rats were used. Alendronate (ALN) monotherapy, dexamethasone (DEX) monotherapy, and ALN/DEX combination therapy were started 4 weeks after tooth extraction of right maxillary first molars. Saline was used as a control (n = 14/group). Implant placement was carried out after grossly and manually confirming no open wounds at 16 weeks post-extraction. Euthanasia was performed at 18 weeks post-extraction. Microcomputed tomography, histological stains and immunostaining to detect blood vessels and macrophages were performed to quantitatively analyze wound healing around implants. ALN/DEX combination therapy significantly increased necrotic bone with more empty lacunae and polymorphonuclear cell infiltration with open wounds when compared with all other therapy groups. Necrotic bone was broadly distributed from the crestal bone to the lower area near the apex of the implants in the ALN/DEX group. Interestingly, both ALN/DEX combination therapy and DEX monotherapy significantly increased the number of CD68⁺NG2^- macrophages, whereas only ALN/DEX combination therapy, not DEX monotherapy, significantly shifted the M1/M2 ratio to M1 by significant increases in M1 macrophages and unchanged M2 macrophages in the connective tissue around implants. Within the limitations of this study, these findings may contribute to understanding the early stages of the histopathology and immunopathology of BRONJ-like lesions around dental implants. Continuous accumulation of M1 macrophages without alteration of M2 macrophages may be associated with developing BRONJ around implants.

[Romosozumab : a new treatment for severe osteoporosis]

Romosozumab is a monoclonal antibody against sclerostin. Its dual effect on bone is to increase formation and decrease resorption. Sub-cutaneous injections of romosozumab are administered monthly for one year and must be relayed with a bone resorption inhibitor. Romosozumab followed by denosumab is associated with high increase of bone mineral density and decrease of fragility fractures. Gain of bone mineral density and reduction of fragility fractures are more important with romosozumab as compared with alendronate. The increase in bone mineral density is higher with romosozumab as compared to teriparatide in patients previously treated with alendronate. The use of romosozumab (Evenity) is admitted for patients with high risk of fractures but without serious vascular events.

Ce4+-triggered cascade reaction for ratiometric fluorescence detection of alendronate

A ratiometric fluorescence assay for alendronate (ALDS) has been designed with Ce⁴⁺-triggered cascade chromogenic reaction. This strategy involves three processes: (1) Ce⁴⁺ oxidizes ascorbic acid (AA) into dehydroascorbic acid (DHAA), which then condenses with o-phenlenediamine (OPD) to generate fluorescent 3-(dihydroxyethyl)furo[3,4-b] quinoxaline-1-one (DFQ), presenting the maximum emission at 434 nm; (2) As oxidase-mimics, Ce⁴⁺ can oxidize OPD into fluorescent 2,3-diaminophenazine (DAP) which shows a strong emission at 568 nm; (3) ALDS inhibits the oxidation ability of Ce⁴⁺ towards OPD, thus inhibiting the generation of DAP. Accordingly, a homogeneous ratiometric fluorescence system with dual emission comes into being and the presence of ALDS can change the fluorescence intensity ratio obviously. With F₄₃₄/F₅₆₈ as readout, ALDS can be detected sensitively with the detection limit of 30 nM. Moreover, this ratiometric method was used to analyze ALDS in both human serum and pharmaceutical samples.

Cost-effectiveness of buffered soluble alendronate 70 mg effervescent tablet for the treatment of postmenopausal women with osteoporosis in Italy

The use of buffered soluble alendronate 70 mg effervescent tablet, a convenient dosing regimen for bisphosphonate therapy, seems a cost-effective strategy compared with relevant alternative treatments for postmenopausal women with osteoporosis aged 60 years and over in Italy.

INTRODUCTION

To assess the cost-effectiveness of buffered soluble alendronate (ALN) 70 mg effervescent tablet compared with relevant alternative treatments for postmenopausal osteoporotic women in Italy.

METHODS

A previously validated Markov microsimulation model was adjusted to the Italian healthcare setting to estimate the lifetime costs (expressed in €2019) per quality-adjusted life-years (QALY) of buffered soluble ALN compared with generic ALN, denosumab, zoledronic acid and no treatment. Pooled efficacy data derived from the NICE network meta-analysis were used for bisphosphonate treatments. Two treatment duration scenarios were assessed: 1 year using persistence data derived from an Italian prospective observational study including 144 and 216 postmenopausal osteoporotic women on buffered soluble ALN and oral ALN, respectively, and 3 years. Analyses were conducted for women 60-80 years of age with a bone mineral density T-score ≤ - 3.0 or with existing vertebral fractures.

RESULTS

In all simulated populations, buffered soluble ALN was dominant (more QALYs, lower costs) compared to denosumab. The cost per QALY gained of buffered soluble ALN compared to generic ALN and no treatment always falls below €20,000 per QALY gained. In the 1-year treatment scenario, zoledronic acid was associated with more QALY than buffered soluble ALN but the cost per QALY gained of zoledronic acid compared with buffered soluble ALN was always higher than €70,000, while buffered soluble ALN was dominant in the 3-year treatment scenario.

CONCLUSION

This study suggests that buffered soluble ALN represents a cost-effective strategy compared with relevant alternative treatments for postmenopausal osteoporosis women in Italy aged 60 years and over.

Bisphosphonates and risk of lung cancer: Protocol for a systematic review and meta-analysis

The association between the use of bisphosphonates (BPs) and the risk of lung cancer has been concerned recently. There is no explicit study indicating that whether the use of BPs would affect the risk of lung cancer. So, we conducted a meta-analysis to figure out the relationship between BPs and lung cancer.We searched the databases of PubMed and Embase. The random effects were used to calculate the pooled odds ratios (ORs) and 95% confidence interval (CIs) for the risk of lung cancer in BPs users compared with non-users. The stability of our results was evaluated by the sensitivity analysis. The publication bias was assessed in our study. The data in our study comes from the public database, therefore ethical approval is not necessary. Also, our study did not involve patient consent.Four studies met our inclusion criteria. All the included studies are cohort studies. Our analysis indicated that there was no significant association between the use of BPs and the risk of lung cancer (OR 1.02, 95%CI 0.85- 1.24, I2 71%). In our secondary analysis, the use of alendronate may increase the risk of lung cancer. The pooled OR of 3 studies is (OR 1.10, 95%CI 0.84-1.45, I2 77%), but when we performed a sensitivity analysis, 1 of the OR is (OR 1.23, 95%CI 1.02-1.49, I2 4.1%).This is the most detailed meta-analysis on this topic. And there was no significant association between the use of BPs and lung cancer. However, exposure to alendronate may increase the risk of lung cancer. More studies are needed to confirm our findings.

Is there a role for bisphosphonates in vascular calcification in chronic kidney disease?

Theoretically bisphosphonates could accelerate or retard vascular calcification. In subjects with low GFR, the position is further confounded by a combination of uncertain pharmacokinetics (GI absorption is poor and inconsistent at all levels of renal function and the effect of low GFR generally is to increase bioavailability) and a highly variable skeletal substrate with extremes of turnover that increase unpredictably further. Although bisphosphonates reduce bone formation by 70-90% in subjects with normal GFR and reduce the ability of bone to buffer exogenous calcium fluxes, in bisphosphonate treated postmenopausal women accelerated vascular calcification has not been documented. The kidneys assist with this buffering, but the capacity to modulate calcium excretion declines as GFR falls, increasing the risk of hypercalcaemia in the event of high calcium influx. In the ESRD patient, decreased buffering capacity substantially increases the risk of transient hypercalcaemia, especially in the setting of dialysis, and as such may promote vascular calcification which is highly prevalent in the CKD population. Low bone turnover may thus be less of a vascular problem in patients with preserved renal function and a bigger problem when the GFR is low. In patients with stage 4 and 5 CKD, adynamic bone disease associates with the severity and progression of arterial calcification, including coronary artery calcification, and further suppression of bone turnover by a bisphosphonate might exacerbate an already high predisposition to vascular calcification. No convincing signal of harm has emerged from clinical studies thus far. For example 51 individuals with CKD stage 3-4 treated with either alendronate 70 mg per week or placebo for 18 months showed no difference in the rate of vascular calcifications. Conversely an observational study of women with stage 3-4 CKD with pre-existing cardiovascular disease found an increased risk of mortality with a hazard ratio of 1.22 (1.04-1.42) in those given bisphosphonates. Direct suppression of vascular calcification by bisphosphonates is probably confined to etidronate - treatment of soft tissue calcification was a recognized indication for this drug and etidronate markedly reduced progression of vascular calcification in CKD patients. Bisphosphonates are analogues of pyrophosphate, a potent calcification inhibitor in bone and soft tissue. Thus the efficacy of etidronate as treatment for soft tissue calcification brought with it a problematic tendency to cause osteomalacia. In contrast, conventional doses of nitrogen-containing bisphosphonates fail to yield circulating concentrations sufficient to exert direct anti-calcifying effects, at least in patients with good renal function and studies using alendronate and ibandronate have yielded inconsistent vascular outcomes.

A new alendronate doped HAP nanomaterial for Pb2+, Cu2+ and Cd2+ effect absorption

In this paper, a new nanobiomaterial, alendronate hydroxyapatite (AL-HAP), was synthesized by the conventional co-precipitation method with alendronate (AL) as dopant, and applied in the removal of heavy metal contaminants for the first time. The characterization results showed that the crystallinity of the AL-HAP nanocomposite biomaterials after doping has been greatly deteriorated, and the pore volume and pore size increased. When the doping amount of AL was 10 %, the maximum adsorption capacity of AL-HAP for Pb²⁺, Cd²⁺ and Cu²⁺ can reach 1431.8, 469 and 226.6 mg/g, respectively, which was much higher than that reported in other literature. Meanwhile, the adsorption mechanism of AL-HAP for heavy metal ions was discussed from both the views of experimental and Multiwfn program theoretical calculation based on density functional theory (DFT). Quantitative molecular surface analysis was carried out for the first time to study the minimum points and the positions of electrostatic potential (ESP) and average local ionization energy(ALIE), as well as the exact values, giving more accurate and reliable analysis conclusions for the reaction sites and binding mode. In addition, the independent gradient model (IGM) method was also firstly applied to investigate the interactions between AL and HAP or AL-HAP nanocomposite with metal ions. AL-HAP is a potential adsorption material for heavy metal wastewater treatment and soil remediation because of its advantages such as convenient synthesis, excellent adsorption performance and no secondary pollution.

Bisphosphonate-based surface biofunctionalization improves titanium biocompatibility

Novel-biofunctionalized surfaces are required to improve the performance of endosseous implants, which are mainly related to the resistance against biocorrosion, as well as for the consideration of osteoinductive phenomena. Among different strategies, the use of bisphosphonate molecules as linkers between titanium dioxide (TiO₂) surfaces and proteins is a distinctive approach, one in which bisphosphonate could play a role in the osseointegration. Thus, to address this issue, we proposed a novel biofunctionalization of TiO₂ surfaces using sodium alendronate (ALN) as a linker and bovine serum albumin as the protein. Physicochemical analysis of the functionalized surfaces was performed using contact angle analyses and surface roughness measurements, which indicated an efficient functionalization. The biocompatibility of the functionalized surfaces was analyzed through the adhesion behavior of the pre-osteoblasts onto the samples. Overall, our data showed a significant improvement concerning the cell adhesion by modulating the adhesion cell-related set of genes. The obtained results show that for modified surfaces there is an increase of up to 100 times in the percentage of cells adhered when compared to the control, besides the extracellular matrix remodeling seemed to be an essential prerequisite for the early stages of cell adhesion on to the biomaterials, which was assayed by evaluating the matrix metalloproteinase activities as well as the gene activations. In the expressions of the Bsp and Bglap2 genes, for the group containing ALN (TiO₂ + ALN), it was observed an increase in expression (approximately sixfold change) when compared to the control. Altogether, our data clearly showed that the bisphosphonate-biofunctionalized surface enhanced the biocompatibility of titanium and claims to further progress preclinical in vivo experimentation.

Effect of Bisphosphonates on the Osteogenic Activity of Osteoprogenitor Cells Cultured on Titanium Surfaces

PURPOSE

This study investigated the effects of bisphosphonates, namely, alendronate and zoledronate, on the osteogenic activity of osteoprogenitor cells cultured on titanium surfaces at therapeutic doses in order to assess if altered osteoblastogenesis could compromise osseointegration and contribute to etiopathogenesis of painful disorders such as bisphosphonates-related osteonecrosis of the jaw (BRONJ) following implant placement.

MATERIALS AND METHODS

MC3T3-E1 Subclone 4 cells were utilized in this study. Therapeutic doses of alendronate and zoledronate were calculated based on reported peak plasma concentrations. The viability, proliferation, adhesion, and mineralization potential of cells was assessed using a LIVE/DEAD stain, alamarBlue assay, immunofluorescence microscopy, and Alizarin Red S staining, respectively.

RESULTS

Therapeutic doses of zoledronate negatively affected cell viability, whereas therapeutic doses of alendronate significantly enhanced cell differentiation and the amount of bone formation compared with the control.

CONCLUSION

The findings of this study may provide some insight into the pathogenesis of BRONJ development following implant placement in patients treated with zoledronate and may have promising implications toward improved wound healing and osseointegration in patients treated with alendronate.

Mechanical Properties of the Mandible in Postmenopausal Women Under Aledronate Treatment

AIMS

This study evaluated the mechanical properties of mandibular bone tissue retrieved from postmenopausal women under alendronate treatment.

METHODS

Twenty postmenopausal women were divided into two groups: healthy postmenopausal subjects (control group) and osteoporotic subjects treated with alendronate (alendronate group). Mandibular bone samples were retrieved with a trephine bur at the time of dental implant placement and fixed in 4% formalin. Samples were processed for hard tissue histology, and the bone surface was analyzed for nanohardness measurement. Nanohardness and elastic modulus were evaluated by using a Berkovich tip with elastic modulus of 1.016x106 MPa, Poisson coefficient of 0.3, and a load of 100 mN. Each cycle was configured with a load time of 18 seconds (speed of 1 mN/second), the discharge time of 18 seconds, and a rest time of 5 seconds during indentation at a depth of 10 μm.

RESULTS

The control group presented the highest values for nanohardness and elastic modulus (p less than 0.05) in relation to the osteoporotic subjects.

CONCLUSIONS

Within the limitations of the study, it can be concluded that treatment with alendronate negatively influenced the mechanical properties of mandibular bone in postmenopausal women by reducing bone nanohardness and elastic modulus.

Bisphosphonates in the management of Paget's disease

The first clinical use of bisphosphonates was in Paget's disease of bone (PDB) when disodium etidronate was found to be effective at suppressing metabolic activity of the disease. Subsequently, PDB became a testing ground for many bisphosphonates using changes in alkaline phosphatase (ALP) as the primary outcome measure in clinical trials. Bisphosphonates are now considered to be the treatment of choice for PDB since they are highly effective at suppressing the elevations in bone turnover that are characteristic of the disease. Short term studies have shown that treatment with alendronate and risedronate can promote formation of lamellar bone in affected sites and improve x-ray appearances in some patients. Bisphosphonates have also been shown to improve bone pain in PDB and within the bisphosphonates, zoledronic acid (ZA) is most likely to give a favourable pain response. Many patients with PDB do not have pain however, even when there is increased metabolic activity and more research is needed to find out why this is the case. The effects of bisphosphonates on complications of PDB such as deformity, pathological fractures and deafness have not been adequately studied since most clinical trials have been short term and have not collected information on these important outcomes. The PRISM and PRISM-EZ studies investigated the long-term effects of bisphosphonates in patients with established PDB using a treat-to-target approach and showed that intensive bisphosphonate therapy aimed at normalising ALP was no more effective than symptom directed treatment with bisphosphonates at preventing complications of PDB. The Zoledronate in the Prevention of Paget's Disease (ZiPP) trial, which is currently in progress, seeks to determine whether early intervention with this potent bisphosphonate might be effective in preventing disease progression. Should the ZiPP study yield positive results, genetic testing coupled to prophylactic bisphosphonate therapy might represent a new indication for these highly effective inhibitors of bone resorption in future years.

Controversies in the treatment of postmenopausal osteoporosis: How long to treat with bisphosphonates?

Osteoporosis is a systemic skeletal disease characterized by reduced bone mass and deterioration of bone tissue microarchitecture leading to an increased risk of fractures. Fragility fractures, especially hip fractures, are associated with a significant reduction in the physical function and quality of life of affected patients, as well as increased mortality, leading to a major financial impact on health care. Many drugs have been registered for the treatment of osteoporosis and very recently, a new anabolic agent, romosozumab, has been approved in some countries. Despite the expansion of efficacious antiresorptive and anabolic therapies in recent years, a concomitant increase in concerns have been raised by physicians, patients and the lay press about the potential for adverse events, especially atypical femoral fractures (AFF) following prolonged use of bisphosphonates. Whatever the mechanism(s) may be, direct or indirect, linking prolonged bisphosphonate use to atypical femoral fractures, this adverse event is very rare in comparison to the magnitude of risk reduction of typical osteoporotic fractures. An estimated 162 osteoporosis-related fractures are prevented for each atypical femoral fracture associated with an anti-resorptive medication. Until a risk calculator for predicting risk of atypical fractures, becomes available in clinical practice, and we view this as an unlikely scenario, it is up to the physician to consider continuing or discontinuing bisphosphonate use after the critical 3-5 year period of treatment with zoledronic acid or alendronate, but close monitoring for the residual bone effects overtime should be planned. For other bisphosphonates, in which no residual effects are expected, drug holiday is usually not applied.

History of risedronate

Herein we review the discovery, development, commercial history and legacy of risedronate or NE-58095, a potent N-containing bisphosphonate developed by scientists at the Cincinnati Miami Valley Laboratories and the Norwich Eaton Laboratories of Procter and Gamble. It is characterized by a hydroxyl substituent (R₁) and a pyridyl-methylene substituent (R₂) at the carbon bridging two phosphonate moieties. It was shown to have greater potency than alendronate in cell-based systems while binding affinity to bone matrix was lower than alendronate, accounting for the relatively rapid offset of bone turnover inhibition when therapy is discontinued. Risedronate was shown to significantly reduce serum alkaline phosphatase and clinical features in patients with Paget's disease and was approved for this indication, at a dose of 30 mg daily for 2 months, in 1998. Formal dose response testing for treatment of osteoporosis was not performed. In large Phase 3 studies, 5 mg risedronate daily increased bone mineral density more than did the 2.5 mg dose. As a result, the 2.5 mg dose was dropped from most of the Phase 3 studies after 12 months. The 5 mg daily dose was approved for treating and preventing postmenopausal osteoporosis and glucocorticoid-induced osteoporosis in 2000. The drug was subsequently approved for treating men with osteoporosis. Following the leads of other companies, weekly and monthly preparations were developed and approved, based on non-inferiority BMD studies vs the 5 mg daily oral dose as was a unique dosing regimen of 75 mg given on 2 consecutive days each month. Finally, to overcome the effect of food on limiting the already poor gastrointestinal absorption of the drug, a once-weekly oral preparation containing the chelating agent EDTA and with an enteric coating delaying dissolution until the tablet was in the small intestine was approved in 2010 to be administered after breakfast. The Alliance for Better Bone Health, a collaboration between Procter & Gamble Pharmaceuticals and sanofi-aventis U.S. was formed to market risedronate as Actonel® and, subsequently, Actonel-EC® or Atelvia®. These drugs are still marketed by sanofi-aventis in some countries. The sale of the pharmaceutical division of Procter & Gamble to Warner Chilcott (US) was based, in large part, on the perceived value and marketability of the risedronate drugs. When marketing targets of Warner-Chilcott were not met, the rights of risedronate were sold to Allergan USA, Inc. which never actively promoted the drug. Generic forms of risedronate were introduced into the United States in 2015 but are rarely used, although several generic forms are actively marketed in other countries.

The challenge of long-term adherence: The role of bone turnover markers in monitoring bisphosphonate treatment of osteoporosis

Oral Bisphosphonates (BPs) are the mainstay of osteoporotic treatment, however long-term adherence remains a challenge, primarily owing to the chronic character of the disease and the regimen complexity. Poor compliance has been shown to have a clear link to fracture risk. The role of bone turnover markers (BTMs) as a tool to ascertain adherence and response to therapy is supported by their rapid response to treatment; a decrease in values is witnessed within days or weeks of commencing treatment. A greater reduction of serum CTX and NTX is evidenced with alendronate and ibandronate compared to risedronate. A change in bone formation BTMs appears to be related to vertebral fracture risk reduction, whereas no significant relationship is evident for hip and non-vertebral fractures. The utility of BTMs as an adjunct for monitoring withdrawal of treatment with oral BP has also been suggested. Finally, studies evaluating BTMs as an intervention, failed to demonstrate any effect on adherence. This review explores the challenge of long-term adherence with bisphosphonates and provides an analytic framework with respect to the role of BTMs in monitoring bisphosphonate treatment, adherence and the offset of treatment effect.

Practical guidance for the use of bisphosphonates in osteoporosis

Bisphosphonates are widely used in the treatment of osteoporosis in postmenopausal women and older men. In clinical trials they have been shown to reduce fractures in women with osteoporosis and there is increasing evidence that they are also effective in women with osteopenia, in whom the majority of fractures occur. In addition to their role as initial therapy in individuals at increased risk of fracture, bisphosphonates are used as sequential therapy after treatment with anabolic drugs. There are no head-to head studies to compare the anti-fracture efficacy of different bisphosphonates, but there is limited evidence that zoledronate treatment results in greater increases in BMD than risedronate or alendronate. This, together with the need for less frequent administration of zoledronate, supports its wider use in clinical practice, particularly if longer dosing intervals than those currently recommended are shown to be effective.

Which Drug Next? Sequential Therapy for Osteoporosis

The proliferation of drugs with unique modes of action for treating osteoporosis has been most welcome. Fear of complications, even though rare, associated with long-term bisphosphonates (BPs) changed prescribing patterns. The BPs are stored in bone for years. Drugs not stored in bone; for example, abaloparatide, teriparatide, denosumab, and romosozumab have expanded our armamentarium for treating osteoporosis but have brought new challenges. Bone accrued during treatment with the last 3 drugs, and perhaps abaloparatide, is lost rapidly after their withdrawal due to rebound increase in bone resorption. Treatment with these drugs must be followed by administration of an antiresorptive agent. The article by Kendler et al. (1) in this issue of JCEM reports alendronate preserves bone accrued during administration of denosumab.

Polydopamine-based surface modification of paclitaxel nanoparticles for osteosarcoma targeted therapy

In order to achieve the purpose of targeting treatment of osteosarcoma, we developed novel paclitaxel (PTX) nanoparticles (Nps) coated with polydopamine (PDA) and grafted by alendronate (ALN) as ligand. Dopamine can be easily polymerized on various surfaces to form a thin PDA film in alkaline environment, which provided a versatile platform to perform secondary reactions for compounds without functional groups. The targeting Nps had a mean particle size of 290.6 ± 2.2 nm and a zeta potential of -13.4 ± 2.7. It was stable in phosphate buffer saline (PBS, pH 7.4), 5% glucose, plasma and displayed sustained drug release behavior. In vitro assay demonstrated the targeting Nps had stronger cytotoxicity against K₇M₂ wt osteosarcoma cells than the non-targeting Nps. Furthermore, in vivo distribution study indicated they could accumulate much more in tumor than non-targeting Nps. This is consistent with the in vivo antitumor study, targeting Nps achieved a better therapeutic effect than Taxol (8 mg kg^-1, i.v.) (71.85% versus 66.53%) and prominently decreased the side effects of PTX. In general, the PTX-PDA-ALN-Nps may offer a feasible and effective strategy for osteosarcoma targeted therapy.

Clinical and Radiographic Assessment of Single or Combined Treatment with Lepidium sativum and Alendronate of Non-Surgically Treated Chronic Periodontitis in Postmenopausal Osteoporotic Women

AIM OF THE STUDY

The aim of the study was to compare the clinical outcomes, radiometric indices (antigonial index and mental index) before and after nonsurgical treatment of chronic periodontitis in postmenopausal osteoporotic women receiving alendronate (ALN) and Lepidium sativum either singly or combined.

MATERIALS AND METHODS

The study was conducted on 45 postmenopausal osteoporotic women with chronic periodontitis. The study population was divided randomly and equally into three groups: A, B and C (15 patients each). Group A: local debridement was performed for these patients. They received ALN at a dose of (70 mg/ once/ week) for six months as regular treatment of osteoporosis. Group B: patients were given finely powdered dried seeds of Lepidium sativum (LS; 1 gm tid) for six weeks plus local debridement. Group C: patients received combined treatment of LS at a dose of 1 gm/tid (for six weeks) and ALN at a dose of 70 mg once weekly for six months plus local debridement. Gingival index (GI), pocket depth (PI) and clinical attachment level (CAL) were measured together with ADAM8 level in the GSF of the study group at baseline, three and six months.

RESULTS

By comparing the means of GI at baseline, three months and six months within the three groups, Group C showed the highest signifi cant decrease in the mean GI (p = 0.01). Comparing the pocket depth and the clinical attachment level, Group B and C showed comparable pocket depth reduction and Group C reported the highest clinical attachment gain at p=0.001. By comparing the mean of radiometric indices of the three groups through the whole study period, Group C showed the greatest increase in the MI index from baseline to six months at p=0.0001. By comparing the mean percentage of change (%) in GI among the three groups, Group C showed the statistically signifi cant highest mean percent decrease in GI. By comparing the mean percentage of change of pocket depth before and after treatment, both Groups B and C showed significantly higher percentage of PD reduction than Group A after three months and six months at p = 0.002 and p = 0.001, respectively, while no signifi cant difference was detected between groups B and C through the whole study period. By comparing mean percentage of changes of CAL, Group C showed the highest percentage of CAL change.

CONCLUSIONS

Within the limits of the study, it is concluded that Lepidium sativum can be used in the treatment of osteoporotic postmenopausal women with chronic periodontitis who refuse treatment with ALN. The combined use of LS and ALN may have a synergistic effect resulting in a more favorable clinical response, increased bone mass than using ALN alone when combined with conventional therapy in treatment of chronic periodontitis in postmenopausal osteoporotic women.

Bone Targeted Delivery of SDF-1 via Alendronate Functionalized Nanoparticles in Guiding Stem Cell Migration

Stem cells are well-known for their great capacity for tissue regeneration. This provides a promising source for cell-based therapies in treating various bone degenerative disorders. However, the major hurdles for their application in transplantation are the poor bone marrow homing and engraftment efficiencies. Stromal cell-derived factor 1 (SDF-1) has been identified as a major stem cell homing factor. With the aims of bone targeted SDF-1 delivery and regulating MSCs migration, alendronate modified liposomal nanoparticles (Aln-Lipo) carrying SDF-1 gene were developed in this study. Alendronate modification significantly increased the mineral binding affinity of liposomes, and facilitated the gene delivery to osteoblastic cells. Up-regulated SDF-1 expression in osteoblasts triggered MSCs migration. Systemic infusion of Aln-Lipo-SDF-1 with fluorescence labeling in mice showed the accumulation in osseous tissue by biophotonic imaging. Corresponding to the delivered SDF-1, the transplanted GFP⁺ MSCs were attracted to bone marrow and contributed to bone regeneration. This study may provide a useful technique in regulating stem cell migration.

Bone diseases: Romosozumab - on track or derailed?

Romosozumab, a recently developed sclerostin inhibitor, stimulates bone formation and inhibits bone resorption, thereby markedly increasing bone mass and reducing fracture risk. But will a red flag regarding possible adverse cardiovascular events derail this promising new drug for osteoporosis?

[BISPHOSPHONATES AS A PREVENTATIVE TREATMENT FOR OSTEOPOROTIC HIP FRACTURES: A MIXED BLESSING]

BACKGROUND

The widespread use of bisphosphonates for treating osteoporosis in the last two decades has raised concern about the complication of atypical hip fractures secondary to bisphosphonate treatment. These fractures may be the result of a minor trauma to the hip or without any trauma at all. It may be heralded by prodromal groin or hip pain. Prolonged bisphosphonate treatment and atypical fractures may exist, but the nature and the extent of this linkage are still unknown. Currently, there is a lack of adequate evidence-based methods or a consensus about the treatment of this unique phenomenon.

METHODS

We retrospectively examined the records of all subtrochanteric hip fracture cases admitted to our department in the years 2010-2014. During that period, we treated a total of 1315 patients:726 patients with pertrochanteric fractures, 514 patients with subcapital fractures and 75 patients with distal subtrochanteric fractures. Among those, 16 patients (1.2%) qualified as atypical hip fractures. The location of the fracture, period of bisphosphonates use, fixation type, complications and recovery were recorded.

RESULTS

The average age of the patients in our study was 76.9 years. All patients were treated with bisphosphonates and over 80% of the patients were treated specifically with Alendronate prior to the fracture. Mean treatment time was 7.8 years. Most of the fractures (75%) were subtrochanteric, and the others were at the femur midshaft. All patients received surgical fixation and all accomplished union of the fractures.

CONCLUSIONS

It seems reasonable to assume a causative relationship between a long term use of bisphosphonates and the occurrence of atypical hip fractures. It is a relatively rare complication; nevertheless, it should be kept in mind during a long term use of bisphosphonates. According to our department's clinical experience we found no delay in bone union with these atypical hip fractures. It seems reasonable to prophylactically fixate atypical stress fractures before they become a full fracture.