Investigate the Therapeutic Effect of Ibandronate Sodium on Knee Osteoarthritis Based on TLRs/MyD88/NF-κB Signaling Pathway in Vitro and in Vivo.

BACKGROUND: For decades, bisphosphonates have primarily found application in clinical practice for the treatment and prevention of bone metastases associated with malignant tumors and various bone metabolic disorders. However, third-generation bisphosphonates like ibandronate have demonstrated significant utility in addressing conditions like osteoporosis (OA) and other bone metabolism-related ailments. Ibandronate, distinguished by its high effectiveness, low toxicity, and ease of administration, has garnered attention for its potential applications in the treatment of rheumatoid arthritis, OA, and orthopedic concerns. In recent years, the utilization of ibandronate sodium in these contexts has sparked considerable interest. Research has pointed to a possible connection between ibandronate and the Toll-like receptors (TLRs), myeloid differentiation factor 88 (MyD88), and nuclear factor-κB (NF-κB) signaling pathway, particularly in the context of inflammation and immunological regulation. Consequently, this study is designed to investigate the therapeutic impact of ibandronate on in vitro and in vivo models of knee osteoarthritis, while also delving into its influence on the TLRs/MyD88/NF-κB pathway. METHOD: Various dosages of ibandronate sodium, including low (10 g/kg), medium (20 g/kg), and high (30 g/kg), were administered following the establishment of both in vivo and in vitro models of knee osteoarthritis (KOA). Post-intervention, an in-depth quantitative analysis of bone tissue microstructure was conducted. The morphology of articular cartilage tissue was observed in vivo, and the modified Mankin score was subsequently calculated. In the in vitro setting, cartilage was entirely isolated, and mRNA and total protein were extracted to measure the expression levels of TLR4, MyD88, and NF-κB at both the mRNA and protein levels. Furthermore, the study explored the effects of Interleukin-1 beta (IL-1ß) on cell proliferation, apoptosis, stromal decomposition enzyme activity, ossification, and the expression of TLR4, MyD88, and NF-κB. RESULT: In the results of the in vivo experiments, several noteworthy findings emerged. The knee curvature, gait score, Mankin score, pathological knee joint injury degree, cartilage protein loss, and trabecular separation within the model group exhibited significant elevations compared to both the sham operation group and the blank control group (p < 0.05). Conversely, bone density, bone volume fraction, and trabecular thickness in the model group displayed lower values in comparison to the sham operation and blank control groups (p < 0.05). Following the administration of ibandronate sodium, there was a progressive improvement in these parameters, with the medium and high-dose groups demonstrating the most favorable outcomes (p < 0.05). Additionally, the model group exhibited the highest expression levels of TLR4, MyD88, and NF-κB, while the ibandronate sodium intervention group displayed reduced expression levels of these markers, with the high-dose group registering the most significant changes (p < 0.05). Turning to the in vitro experiments, it was observed that the cell proliferation capacity and ossification degree of the IL-1ß-induced group experienced declines, concomitant with an increase in stromal decomposition enzyme activity and cell apoptosis rate (p < 0.05). However, post-intervention with ibandronate sodium, all these indicators gradually returned to normal, with the medium-dose group exhibiting the most notable improvements. The expression levels of TLR4, MyD88, and NF-κB in the IL-1ß-induced group showed an increase, while the expression levels in the ibandronate sodium intervention group displayed a decrease, particularly in the high-dose group (p < 0.05). CONCLUSIONS: Ibandronate sodium demonstrates a protective effect on articular chondrocytes and exhibits the potential to decelerate the pathological progression of knee osteoarthritis (KOA) in rats. This mechanism is likely achieved through the inhibition of the TLRs/MyD88/NF-κB signaling pathway.

Comparison of the prophylactic use of ibandronate and its use in early-stage osteonecrosis in rats with steroid-induced osteonecrosis of the femoral head.

OBJECTIVES: The aim of this study was to investigate the effects of ibandronate before and after the onset of osteonecrosis in rats with steroid-induced osteonecrosis of the femoral head. MATERIALS AND METHODS: A total of 24 female Sprague-Dawley rats were used in this study. Three groups were formed with eight rats in each group. The first group was the prophylactic group that received ibandronate treatment before and after the onset of osteonecrosis (Group PT). The second group received ibandronate treatment three weeks after the development of osteonecrosis (Group TAO). The third group was the control group in which osteonecrosis was created, but only normal saline (NS) was given. At the end of the study, all rats were sacrificed, and their right femoral heads were removed, fixed with formalin, and sent for micro-computed tomography. Hematoxylin-eosin (H&E) and immunohistochemical examinations of the right femoral head sections were performed. RESULTS: In the PT group, the trabecular thickness was significantly higher compared to those of the TAO and control groups (p<0.05). The trabecular thickness did not significantly differ between the TAO and control groups. The trabecular bone pattern factor was significantly higher in the PT group compared to the control and TAO groups (p<0.05); however, it showed no significant difference between the TAO and control groups. The incidence of type 2 osteonecrosis in the PT and TAO groups was significantly lower than that in the control group (p<0.05). The incidence of tissue-non-specific alkaline phosphatase (TNAPase) immunoreactivity of osteoblast positivity was significantly higher in the PT and TAO groups compared to the control group (p<0.05), whereas the incidence of TRAPase immunoreactivity of osteoclastic positivity was significantly lower in the PT and TAO groups compared to the control group (p<0.05). CONCLUSION: Intravenous administration of ibandronate before the onset of the disease was more effective in the treatment of osteonecrosis in rats with steroid-induced osteonecrosis of the femoral head.

Bisphosphonate type-dependent cell viability suppressive effects of carbon nanohorn-calcium phosphate-bisphosphonate nanocomposites.

In the process of bone metastasis, tumor cells spread to the bones to activate osteoclasts, which cause pathological bone resorption and destruction. Bisphosphonates (BPs) inhibit osteoclast activation to resorb bone, reducing bone pain and fracture. We previously developed a nanocomposite for potential localized treatment of bone metastasis by loading a BP compound, ibandronate, onto oxidized carbon nanohorns (OxCNHs), a next-generation drug carrier, using calcium phosphates (CaPs) as mediators to generate OxCNH-CaP-BP nanocomposites. The objective of the present study was to determine nanocomposite formation and biological properties of nanocomposites constructed from two BPs, zoledronate and pamidronate. In vitro tests using murine macrophages (RAW264.7 cells) and osteoclasts differentiated from RAW264.7 cells revealed that the resulting OxCNH-CaP-BP nanocomposites suppressed cell viability in a BP type-dependent manner and more effectively than OxCNHs or BPs alone. The mechanism for the potent and BP type-dependent suppression of cell viability by OxCNH-CaP-BP nanocomposites, based on their relative cellular uptake and reactive oxygen species generation, is also discussed. The present study supports the conclusions that BPs can be loaded onto OxCNHs using CaPs as mediators, and that OxCNH-CaP-BP nanocomposites are putative medicines for localized treatment of metastatic bone destruction.

Verification of efficacy and safety of ibandronate or denosumab for postmenopausal osteoporosis after 12-month treatment with romosozumab as sequential therapy: The prospective VICTOR study.

Romosozumab is a potent drug for treating postmenopausal osteoporosis but has a limited dosing period of 12 months. Bone mineral density (BMD) decreases soon after romosozumab discontinuation, thus emphasizing the importance of appropriate sequential treatment. The present VICTOR randomized controlled study compared the efficacy of ibandronate and denosumab as sequential therapy options following 12-month romosozumab treatment. Subjects completing 12 months of romosozumab administration for severe postmenopausal osteoporosis were randomly assigned to receive either ibandronate or denosumab for an additional 12 months. The primary outcome of interest was the percentage changes in BMD at the lumbar spine, total hip, and femoral neck from 12 months (completion of romosozumab) to 18 and 24 months of total treatment (6 and 12 months, respectively, after the conversion to sequential therapy). Secondary outcomes included alterations in serum bone turnover markers and the incidence of adverse events. Sixty-two subjects each in the ibandronate and denosumab groups completed the sequential therapy. The respective percentage changes in BMD at the lumbar spine from 12 months to 24 months were 2.5 % in the ibandronate group and 5.4 % in the denosumab group. At 24 months, we observed significant differences versus 12 months for both groups as well as between the groups (all P < 0.01), showing a superior ability to increase BMD at the lumbar spine for denosumab over ibandronate. BMD gains at the total hip and femoral neck exhibited comparably favorable trends. P1NP and TRACP-5b were significantly decreased from 12 to 24 months (-64.9 % and - 26.8 % in the ibandronate group and - 67.4 % and - 36.3 % in the denosumab group, respectively; all P < 0.001 versus 12 months). Several minor adverse events were recorded in both groups, none of which led to the discontinuation of the trial. The VICTOR study revealed that denosumab could be considered more effective than ibandronate, with few severe adverse events, for the enhancement of BMD as a sequential agent after romosozumab in postmenopausal osteoporosis patients.

Pharmacological Therapies for Osteoporosis: A Bayesian Network Meta-Analysis.

BACKGROUND Numerous randomized controlled trials (RCTs) have evaluated pharmacological therapies for osteoporosis. The aim of this Bayesian network meta-analysis was to compare the efficacy and safety of pharmacological therapies for osteoporosis patients. MATERIAL AND METHODS The electronic databases of PubMed, Embase, and Cochrane Library were systematically searched for eligible RCTs from their inception up to January 2021. The primary endpoints were all fractures, vertebral fractures, and non-vertebral fractures, while the secondary endpoints were fractures at hip or peripheral locations, bone mineral density (BMD) at various sites, and potential adverse events. RESULTS We included 79 RCTs reporting a total of 108 797 individuals in the final quantitative analysis. The results of network analysis indicated that romosozumab (92.1%) was the most effective in reducing the risk for all fractures, with the best therapeutic effects on vertebral fracture (97.2%) and non-vertebral fracture (88.0%). Romosozumab (92.5%) provided better therapeutic effects for the reduction of hip fracture. The best treatment agents for improving whole-body BMD (100.0%), spine BMD (95.7%), hip BMD (92.4%), femoral neck BMD (86.7%), and trochanter BMD (95.5%) were alendronate, strontium ranelate, ibandronate, risedronate, and ibandronate, respectively. Finally, the use of bazedoxifene was associated with the highest incidence of any upper-gastrointestinal event, nasopharyngitis, and back pain, while risedronate was associated with higher incidence of abdominal pain and dyspepsia. CONCLUSIONS This study found that romosozumab yielded the best effects for preventing fracture risk, while abaloparatide was the most effective in reducing the risk of vertebral fracture and non-vertebral fracture.

Combination treatment with ibandronate and eldecalcitol prevents osteoporotic bone loss and deterioration of bone quality characterized by nano-arrangement of the collagen/apatite in an ovariectomized aged rat model.

Combination therapy with bisphosphonates and vitamin D3 analogs has been frequently used for the treatment of osteoporosis. However, its effects on bone anisotropies, such as orientations of collagen and apatite at the nanometer-scale, which is a promising bone quality index, and its trabecular architecture at the micrometer scale, are not well understood despite its important mechanical properties and its role in fracture risk. In the present study, we analyzed the effects of ibandronate (IBN), eldecalcitol (ELD), and their combination on the collagen/apatite orientation and trabecular architectural anisotropy using an estrogen-deficiency-induced osteoporotic rat model. Estrogen deficiency caused by ovariectomy (OVX) excessively increased the degree of collagen/apatite orientation or trabecular architectural anisotropy along the craniocaudal axis in the lumbar vertebra compared to that of the sham-operated group. The craniocaudal axis corresponds to the direction of principal stress in the spine. The excessive material anisotropy in the craniocaudal axis contributed to the enhanced Young's modulus, which may compensate for the reduced mechanical resistance by bone loss to some extent. The solo administration of IBN and ELD prevented the reduction of bone fraction (BV/TV) determined by µ-CT, and combination therapy showed the highest efficacy in BV/TV gain. Furthermore, the solo administration and combination treatment significantly decreased the degree of collagen/apatite orientation to the sham level. Based on the results of bone mass and collagen/apatite orientation, combination treatment is an effective strategy. This is the first report to demonstrate the efficacy of IBN, ELD, and combination treatment with IBN and ELD relative to the bone micro-architectural anisotropy characterized by collagen/apatite orientation.

Ibandronate Suppresses Changes in Apatite Orientation and Young's Modulus Caused by Estrogen Deficiency in Rat Vertebrae.

Bone material quality is important for evaluating the mechanical integrity of diseased and/or medically treated bones. However, compared to the knowledge accumulated regarding changes in bone mass, our understanding of the quality of bone material is lacking. In this study, we clarified the changes in bone material quality mainly characterized by the preferential orientation of the apatite c-axis associated with estrogen deficiency-induced osteoporosis, and their prevention using ibandronate (IBN), a nitrogen-containing bisphosphonate. IBN effectively prevented bone loss and degradation of whole bone strength in a dose-dependent manner. The estrogen-deficient condition abnormally increased the degree of apatite orientation along the craniocaudal axis in which principal stress is applied; IBN at higher doses played a role in maintaining the normal orientation of apatite but not at lower doses. The bone size-independent Young's modulus along the craniocaudal axis of the anterior cortical shell of the vertebra showed a significant and positive correlation with apatite orientation; therefore, the craniocaudal Young's modulus abnormally increased under estrogen-deficient conditions, despite a significant decrease in volumetric bone mineral density. However, the abnormal increase in craniocaudal Young's modulus did not compensate for the degradation of whole bone mechanical properties due to the bone loss. In conclusion, it was clarified that changes in the material quality, which are hidden in bone mass evaluation, occur with estrogen deficiency-induced osteoporosis and IBN treatment. Here, IBN was shown to be a beneficial drug that suppresses abnormal changes in bone mechanical integrity caused by estrogen deficiency at both the whole bone and material levels.

Geranyl-geraniol addition affects potency of bisphosphonates-a comparison in vitro promising a therapeutic approach for bisphosphonate-associated osteonecrosis of the jaw and oral wound healing.

PURPOSE: Analysis of the influence of geranyl-geraniol (GG) addition on four bisphosphonate derivatives regarding their influence on cell viability and migration ability of bone metabolism and endothelial cells in vitro. METHODS: Clodronate, pamidronate, ibandronate, and zoledronate were observed with and without GG addition, for their effect on human osteoblasts (HOB), normal human dermal fibroblasts (NHDF), human endothelial progenitor cells (EPC), and endothelial cells of the human umbilical cord (HUVEC) using migration-, MTT-, and colony-forming cell assays. RESULTS: Data pointed to a depressing effect of all bisphosphonates on the migration ability of NHDF, EPC, and HOB. MTT assay demonstrated a decreased cell viability of HUVEC of all bisphosphonates in a 50 µM concentration and of NHDF when treated with 50 µM of clodronate, ibandronate, or zoledronate. Tested drugs showed a depressing effect on colony-forming potential of EPC even in a 5 µM concentration. GG addition demonstrated an attenuate impact on bisphosphonate effect on all primary cell cultures, respectively. CONCLUSION: In vitro comparison showed that the addition of GG weakens the effect of all bisphosphonates examined. It supports investigations that suggest GG to be able to prevent bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) in vivo. Future clinical trials may discover the local therapeutic use of GG for the prevention of BP-ONJ.

Ibandronate-Loaded Carbon Nanohorns Fabricated Using Calcium Phosphates as Mediators and Their Effects on Macrophages and Osteoclasts.

Carbon nanohorns (CNHs), a type of nanocarbon, have been studied for the application of drug delivery systems (DDSs) because they are easily functionalized, support bone regeneration, can be used to perform photohyperthermia, have low toxicity, and are easily phagocytosed by macrophages. To take advantage of these features of CNHs, we developed a DDS for the local treatment of bone metastasis by loading the antibone resorption drug ibandronate (IBN) onto CNHs. The poor adsorption of IBN onto CNHs due to the weak hydrophilic-hydrophobic interaction was overcome by using calcium phosphates (CaPs) as mediators. In the fabrication process, we used oxidized CNH (OxCNH), which is less hydrophobic, onto which IBN was coprecipitated with CaP from a labile supersaturated CaP solution. OxCNH-CaP-IBN composite nanoparticles exerted stronger cell-suppressive effects than OxCNH and IBN in both murine macrophages (RAW264.7 cells) and osteoclasts (differentiated from RAW264.7 cells). OxCNH-CaP-IBN composite nanoparticles were efficiently phagocytosed by macrophage cells, where they specifically accumulated in lysosomes. The stronger cell-suppressive effects were likely due to intracellular delivery of IBN, i.e., the release of IBN from OxCNH-CaP-IBN composite nanoparticles via dissociation of CaP in the acidic environment of lysosomes. Our findings suggest that OxCNH-CaP-IBN composite nanoparticles are potentially useful for the local treatment of metastatic bone destruction.

Enhancement of Oral Bioavailability of Ibandronate Through Gastroretentive Raft Forming Drug Delivery System: In Vitro and In Vivo Evaluation.

BACKGROUND: Bisphosphonates have very low bioavailability and cause irritation of the esophagus and stomach. This study was planned to improve the oral bioavailability of ibandronate through the formation of a raft in the stomach. Bisphosphonate-induced irritation of the esophagus and stomach is prevented by the formation of a raft. MATERIALS AND METHODS: The nanostructured raft was developed through the use of nanosized citrus pectin (NCP). The particle size of NCP was measured by zeta sizer and SEM. The percentage of NCP and the neutralization profile of raft was studied. The ibandronate, polymers, and the developed formulation were characterized by FTIR, XRD, TGA, and DSC. The release of ibandronate was studied in 0.1 N HCl, 0.5 N HCl, 1 N HCl, and simulated gastric fluid (SGF) and a cell viability study was performed using Caco-2 cells. The PPR5 formulation and Bonish 150 mg tablets were selected as test and reference formulations, respectively, for pharmacokinetic study. Twelve healthy albino rats were taken and divided into two groups using a Latin square crossover design, and the blood samples were collected for 24 hours. RESULTS: The SEM image showed that the particle size of NCP was 159 nm. The raft of PPR5 showed 94% NCP and 45 minutes duration of neutralization. The FTIR and XRD showed chemical stability and a uniform distribution of ibandronate in the raft. The TGA and DSC indicated the thermal stability of formulation. The release of 99.87% ibandronate at 20 minutes was observed in the SGF. The values of C max for the reference and test formulations were 493±0.237 ng/mL and 653±0.097 ng/mL, respectively. The AUC(0-t) of the reference and test formulations was 3708.25±3.418 ng/mL.h and 6899.25±3.467 ng/mL.h, respectively. CONCLUSION: The NCP has been successfully prepared from citrus pectin and has shown effective porous raft formation. The bioavailability of the ibandronate from newly developed PPR5 was higher than the already marketed formulation.

Bisphosphonates inhibit surface-mediated osteogenesis.

Bisphosphonates (BPs) target osteoclasts, slowing bone resorption thus providing rationale to support osseointegration. However, BPs may negatively affect osteoblasts, impairing peri-implant bone formation. The goal of this study was to assess the effects BPs have on surface-mediated osteogenesis of osteoblasts. MG63 cells were cultured on 15-mm grade 2 titanium disks: smooth, hydrophobic-microrough, or hydrophilic-microrough (Institut Straumann AG, Basel, Switzerland). Tissue culture polystyrene (TCPS) was used as a control. At confluence, cells were treated with 0, 10-8 , 10-7 , and 10-6 M of alendronate, zoledronate, or ibandronate for 24 hr. Sprague Dawley rats were also treated with 1 µg/kg/day ibandronate or phosphate-buffered saline control for 5 weeks. Calvarial osteoblasts (rat osteoblasts [rOBs]) were isolated, characterized, and cultured on surfaces. Osteogenic markers in the media were quantified using ELISAs. BP treatment reduced osteocalcin, osteoprotegerin, osteopontin, bone morphogenetic protein-2, prostaglandin E2 , transforming growth factor ß1, interleukin 10, and vascular endothelial growth factor in MG63 cells. The effect was more robust on rough surfaces, and higher concentrations of BPs stunted production to TCPS/PT levels. Ibandronate conditioned rOBs produced less osteogenic markers similar to direct BP treatment. These results suggest that BP exposure jeopardizes the pro-osteogenic response osteoblasts have to microstructured surfaces. Their effects persist in vivo and negatively condition osteoblast response in vitro. Clinically, BPs could compromise osseointegration.

Impact of bisphosphonates on the proliferation and gene expression of human fibroblasts.

The aim of this study was to elucidate the role of fibroblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ), evaluating the effect of zoledronate, alendronate, and ibandronate on the proliferation of fibroblasts and on their expression of genes essential for fibroblast physiology. Human CCD-1064Sk epithelial fibroblast cells were incubated in culture medium with 10-5, 10-7, or 10-9 M zoledronate, alendronate, or ibandronate. The proliferative capacity of fibroblasts was determined by spectrophotometry (MTT) at 24 of culture. Real-time polymerase chain reaction (RT-PCR) was used to study the effects of BPs at a dose of 10-9 M on the expression of FGF, CTGF, TGF-ß1, TGFßR1, TGFßR2, TGFßR3, DDR2, α-actin, fibronectin, decorin, and elastin. Fibroblasts proliferation was significantly increased at the lowest dose (10-9M) of each BP but was not affected at the higher doses (10-5 and 10-7M). The proliferation increase may be related to the rise in TGF-ß1 and TGFßR1 expression detected after the treatment of cells with 10-9M of zoledronate, alendronate, or ibandronate. However, the expression of CTGF, DDR2, α-actin, fibronectin, and decorin decreased versus controls. The results of this in vitro study indicate that a very low BP dose (10-9 M) can significantly affect the physiology of fibroblasts, increasing their proliferative capacity and modulating the expression of multiple genes involved in their growth and differentiation.

Micro-CT imaging analysis for the effects of ibandronate and eldecalcitol on secondary osteoporosis and arthritis in adjuvant-induced arthritis rats.

We investigated the effects of ibandronate, a bisphosphonate; eldecalcitol, an active vitamin D3 analogue; and combination treatment with both agents on secondary osteoporosis and arthritis using rats with adjuvant-induced arthritis. Arthritis was induced in 8-week-old male Lewis rats. Rats were randomized into four treatment groups and an untreated normal control group: ibandronate, eldecalcitol, ibandronate + eldecalcitol, vehicle, and control. Paw thickness was measured to evaluate arthritis. Joint destruction was evaluated histomorphometrically by the ankle joint stained with Fast Green and safranin O. The femur and lumbar spine were scanned using dual-energy X-ray absorptiometry, and the distal femur was scanned using micro-computed tomography for bone mineral density (BMD) and trabecular microstructural evaluations. Ibandronate and/or eldecalcitol increased BMD in both the lumbar vertebrae and femur and improved several microstructural parameters (bone volume/total volume, structure model index, trabecular number, and trabecular separation of the distal femur). In addition, there was an additive effect of combination treatment compared with single treatments for most trabecular parameters, including BMD and bone volume. However, ibandronate and/or eldecalcitol did not inhibit arthritis and joint destruction. Combination treatment with ibandronate and eldecalcitol may be effective for secondary osteoporosis associated with arthritis.

Effectiveness of monthly intravenous ibandronate on the low responders to oral bisphosphonate: the MOVEMENT study.

The MOVEMENT study was designed to assess the effectiveness of monthly intravenous ibandronate on bone mineral density (BMD) in daily clinical practice in Japanese patients with primary osteoporosis whose lumbar spine BMD did not increase despite oral bisphosphonate therapy. This study was a multicenter, prospective, interventional study (52 sites; August 2015 to March 2018). Patients aged ≥ 50 years with primary osteoporosis, evaluated as low responders to oral bisphosphonate treatment for 1-3 years, continued on their existing oral bisphosphonate or switched to monthly intravenous ibandronate (1 mg) for 12 months. The primary endpoint was change in lumbar spine BMD from baseline to 12 months in the intravenous ibandronate group (IV IBN). A total of 240 and 141 patients were enrolled in the IV IBN and oral bisphosphonate groups (OBP), respectively. At 12 months, a significant increase in mean percent change from baseline in lumbar spine BMD was observed in the IV IBN (2.70%). This change was also significant at 6 months (1.92%). Similarly, the change in total hip BMD showed a significant increase at 12 months (0.78%). In the IV IBN, the responder rate, percentage of patient whose change from baseline of lumbar spine BMD has greater than 0%, for lumbar spine BMD was high at both 6 (72.3%, 141/195 patients) and 12 (78.0%, 145/186 patients) months. No new safety concerns were observed in either treatment group. Treatment with intravenous ibandronate significantly increased lumbar spine BMD without any new safety concerns in Japanese patients with osteoporosis who showed low response to existing oral bisphosphonates.

Farnesyl Pyrophosphate Synthase Blocker Ibandronate Reduces Thoracic Aortic Fibrosis in Diabetic Rats.

BACKGROUND: This study assessed the effect of ibandronate (IBN), a farnesyl pyrophosphate synthase (FPPS) inhibitor, on vascular remodeling in diabetic rats. METHODS: A rat model of diabetes was induced by a high-fat and high-sugar diet combined with a small dose of streptozotocin. The diabetic rats received 5 µg/kg of ibandronate solution or normal saline subcutaneously every morning for 16 weeks. The morphology of the thoracic aorta was assessed by hematoxylin and eosin and Masson's trichrome staining techniques. Gene expression levels of connective tissue growth factor (CTGF) and FPPS were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. CTGF and FPPS protein levels were determined by Western blotting analysis. RESULTS: Rats with diabetes mellitus showed moderate hyperglycemia, insulin resistance, hyperlipidemia and thoracic aortic fibrosis. FPPS was significantly upregulated in the thoracic aorta from diabetic animals. Interestingly, IBN treatment for 16 weeks alleviated the diabetes-induced histopathologic changes in the thoracic aortic wall and reduced CTGF protein and mRNA levels. CONCLUSIONS: These findings provided evidence that FPPS is involved in thoracic aortic fibrosis in diabetic rats. Meanwhile, IBN could alleviate vascular remodeling in diabetic animals.

Effects of discontinuing oral bisphosphonate treatments for postmenopausal osteoporosis on bone turnover markers and bone density.

The antiresorptive potency varies between different bisphosphonates. We investigated the effect of stopping oral bisphosphonate treatment for postmenopausal osteoporosis (ibandronate, alendronate, risedronate) on BTMs and BMD. After stopping treatment, all three groups showed an increase in BTMs and a decrease in hip BMD; however, none returned to pre-treatment baseline values. INTRODUCTION: Bisphosphonates (BPs) continue to suppress bone turnover markers (BTMs) after treatment has stopped, leading to the suggestion that a pause in treatment could be considered for low-risk patients. Indirect comparisons suggest that after cessation of treatment, the effects on bone may differ between drugs. We investigated the effects of stopping oral BP treatments for postmenopausal osteoporosis on BTMs and bone mineral density (BMD). METHODS: We studied postmenopausal osteoporotic women who had previously taken part in a 2-year randomised study of three oral BPs (ibandronate, alendronate, or risedronate). At the end of the study, women with hip BMD T-score > - 2.5 and considered clinically appropriate to discontinue treatment were invited to participate in a further 2-year observational study. Biochemical response was assessed using BTMs, and BMD was measured by dual-energy X-ray absorptiometry. RESULTS: All BTMs increased after treatment withdrawal but remained below the pre-treatment baseline with less suppression of BTMs for the risedronate group compared to alendronate and ibandronate up to 48 weeks. There was no difference between the BP groups 96 weeks after stopping treatment. The change in BMD during the 96 weeks after stopping treatment was - 1.6% (95% CI - 1.9 to - 1.2, P < 0.001) for the total hip and - 0.6% (95% CI - 1.1 to - 0.2, P = 0.17) at the lumbar spine with no difference between the three BP groups (P = 0.85 and P = 0.48, respectively). CONCLUSION: For all treatment groups, there was an increase in BTMs and a decrease in hip BMD after stopping BPs for 2 years; however, none returned to pre-treatment baseline values.

Effects of an oral bisphosphonate and three intravenous bisphosphonates on several cell types in vitro.

OBJECTIVE: To analyze the influence of an oral bisphosphonate and compare the potency to intravenous bisphosphonates on various cell types as regards the rarity of bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) caused by oral bisphosphonate. MATERIALS AND METHODS: A viability assay (MTT), a migration assay (Boyden chamber), and an apoptosis assay (Caspase-Glo® 3/7) were performed to analyze the effect of bisphosphonates on human fibroblasts, umbilical vein endothelial cells (HUVEC), and osteoblasts. RESULTS: Alendronate and intravenous bisphosphonates suppressed cell viability and migration, and induced apoptosis in all tested cell types. Alendronate had a greater impact than ibandronate on the characteristics in fibroblasts and osteoblasts but not as strong as zoledronate. CONCLUSIONS: The incidence of BP-ONJ in oral bisphosphonate treatment is reported to be much lower than that in intravenous bisphosphonates. However, the influences of alendronate on human cells were at least as strong as ibandronate, although it was lower than zoledronate. CLINICAL RELEVANCE: Alendronate showed strong enough effects to suppress human somatic cells and was comparable to certain intravenous bisphosphonates in potency. This study suggests that the lower incidence of BP-ONJ in alendronate treatment is not originated by its potency, but might be due to the low bioavailability of alendronate, lower dosing on a daily basis, and having no additional therapies.

Ibandronate metal complexes: solution behavior and antiparasitic activity.

To face the high costs of developing new drugs, researchers in both industry and academy are looking for ways to repurpose old drugs for new uses. In this sense, bisphosphonates that are clinically used for bone diseases have been studied as agents against Trypanosoma cruzi, causative parasite of Chagas disease. In this work, the development of first row transition metal complexes (M = Co2+, Mn2+, Ni2+) with the bisphosphonate ibandronate (iba, H4iba representing the neutral form) is presented. The in-solution behavior of the systems containing iba and the selected 3d metal ions was studied by potentiometry. Mononuclear complexes [M(Hxiba)](2-x)- (x = 0-3) and [M(Hiba)2]4- together with the formation of the neutral polynuclear species [M2iba] and [M3(Hiba)2] were detected for all studied systems. In the solid state, complexes of the formula [M3(Hiba)2(H2O)4]·6H2O were obtained and characterized. All obtained complexes, forming [M(Hiba)]- species under the conditions of the biological studies, were more active against the amastigote form of T. cruzi than the free iba, showing no toxicity in mammalian Vero cells. In addition, the same complexes were selective inhibitors of the parasitic farnesyl diphosphate synthase (FPPS) enzyme showing poor inhibition of the human one. However, the increase of the anti-T. cruzi activity upon coordination could not be explained neither through the inhibition of TcFPPS nor through the inhibition of TcSPPS (T. cruzi solanesyl-diphosphate synthase). The ability of the obtained metal complexes of catalyzing the generation of free radical species in the parasite could explain the observed anti-T. cruzi activity.

In Vitro Investigation of the Antimicrobial Effect of Three Bisphosphonates Against Different Bacterial Strains.

PURPOSE: Since the first descriptions of medication-related osteonecrosis of the jaw (MRONJ) in 2003, the pathogenesis has remained unanswered. Recent histomorphometric studies have found several microorganisms, including Actinomyces, Bacillus, Fusobacterium, Staphylococcus, Streptococcus, Selenomonas, Treponema, and Candida albicans in necrotic bone. Polymerase chain reaction studies have recently confirmed the occurrence of 48 genera. Only a few studies have examined the antimicrobial effect of bisphosphonates (BPs). The influence of bacterial growth on the etiology remains unclear. The aim of the present study was the in vitro investigation of the antimicrobial effect of 3 BPs against different bacterial strains. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 48 strains from 40 species were determined in microdilution assays against pamidronic, ibandronic, and zoledronic acid. RESULTS: Growth of gram-positive oral microbiota, which account for most microorganisms in MRONJ, was present for 2 of 22 species; 6 of 26 gram-negative species and 9 of 13 anaerobes were inhibited. The MIC values were compared with the BP bone concentrations from previous reports. Of the 48 strains, 9 had an MIC or MBC less than the bone concentrations. CONCLUSIONS: The results of the present study have demonstrated that BPs have an inhibitory effect on selected bacterial species and might inhibit the growth of some relevant pathogens in osteonecrosis. However, most of the species tested were unaffected at the concentration levels assumed present in the human jawbone. The clinical relevance of these in vitro data will better be clarified with reliable data on the BP concentrations in the human jawbone. The present study has provided a first approach toward the assessment of the interaction of oral bacteria and BPs.