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Background: It is well-known that oral surgical procedures pose a high risk for medication-related osteonecrosis of the jaw in patients taking bisphosphonates. Although some position papers and guidelines have been published with regard to its treatment, few studies have investigated prevention methods. This study investigates the effectiveness of methenolone enanthate, an anabolic steroid, for the prevention of medication-related osteonecrosis of the jaw., Methods: Thirty-six Wistar rats were divided into three groups. Two experimental groups, Z and ZM, took zoledronic acid for 6 weeks prior to extraction of the left maxillary first molar. The Group ZM also was given methenolone enanthate continuously for 1 week before and 4 weeks after the extraction. The control group was not given any medication. The rats were euthanized 5 weeks after extraction. The extraction socket was evaluated clinically for bone exposure and histologically for inflammation, hyperemia, collagen fibers, epithelialization, number of osteoclasts, and empty lacunae., Results: Six rats died during the experimental research. The bone exposure rate, mean numbers of attached osteoclasts (in 40× magnification), and empty lacunae (in 100× magnification) were 0%, 4%, and 0.8% in Group C; 75%, 1%, and 8% in Group Z; and 10%, 2.1%, and 3% in Group ZM, respectively. Significant differences exist between all groups regarding the number of empty lacunae. There were significant differences between Group C/ZM and Group Z in terms of bone exposure rate, inflammation, hyperemia, collagen fiber organization, and epithelialization., Conclusion: In our tested preclinical model, methenolone enanthate has shown potential for preventing medication-related osteonecrosis of the jaw., (© 2024 The Author(s). Journal of Oral Pathology & Medicine published by John Wiley & Sons Ltd.)

Vascular calcification affects the prognosis of patients with renal failure. Bisphosphonates are regarded as candidate anti-calcifying drugs because of their inhibitory effects on both calcium-phosphate aggregation and bone resorption. However, calcification in well-known rodent models is dependent upon bone resorption accompanied by excessive bone turnover, making it difficult to estimate accurately the anti-calcifying potential of drugs. Therefore, models with low bone resorption are required to extrapolate anti-calcifying effects to humans. Three bisphosphonates (etidronate, alendronate, and FYB-931) were characterised for their inhibitory effects on bone resorption in vivo and calcium-phosphate aggregation estimated by calciprotein particle formation in vitro. Then, their effects were examined using two models inducing ectopic calcification: the site where lead acetate was subcutaneously injected into mice and the transplanted, aorta obtained from a donor rat. The inhibitory effects of bisphosphonates on bone resorption and calcium-phosphate aggregation were alendronate > FYB-931 > etidronate and FYB-931 > alendronate = etidronate, respectively. In the lead acetate-induced model, calcification was most potently suppressed by FYB-931, followed by alendronate and etidronate. In the aorta-transplanted model, only FYB-931 suppressed calcification at a high dose. In both the models, no correlation was observed between calcification and bone resorption marker, tartrate-resistant acid phosphatase (TRACP). Results from the lead acetate-induced model showed that inhibitory potency against calcium-phosphate aggregation contributed to calcification inhibition. The two calcification models, especially the lead acetate-induced model, may be ideal for the extrapolation of calcifying response to humans because of calcium-phosphate aggregation rather than bone resorption as its mechanism., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Changes in the structure of bone can occur in space as an adaptive response to microgravity and on Earth due to the adaptive effects to exercise, to the aging of bone cells, or to prolonged disuse. Knowledge of cell-mediated bone remodeling on Earth informs our understanding of bone tissue changes in space and whether these skeletal changes might increase the risk for fractures or premature osteoporosis in astronauts. Comparisons of skeletal health between astronauts and aging humans, however, may be both informative and misleading. Astronauts are screened for a high level of physical fitness and health, are launched with high bone mineral densities, and perform exercise daily in space to combat skeletal atrophy as an adaptive response to reduced weight-bearing function, while the elderly display cellular and tissue pathology as a response to senescence and disuse. Current clinical testing for age-related bone change, applied to astronauts, may not be sufficient for fully understanding risks associated with rare and uniquely induced bone changes. This review aims to (i) highlight cellular analogies between spaceflight-induced and age-related bone loss, which could aid in predicting fractures, (ii) discuss why overreliance on terrestrial clinical approaches may miss potentially irreversible disruptions in trabecular bone microarchitecture induced by spaceflight, and (iii) detail how the cellular effects of the bisphosphonate class of drugs offer a prophylactic countermeasure for suppressing the elevated bone resorption characteristically observed during long-duration spaceflights. Thus the use of the bisphosphonate will help protect the bone from structural changes while in microgravity either along with exercise or alone when exercise is not performed, e.g. after an injury or illness.

Macrophages are important regulators of bone remodeling, and M1 polarization is observed in the setting of medication-related osteonecrosis of the jaws (MRONJ). Here, we characterize the phenotype of macrophages during early stages of MRONJ development in zoledronate (ZA)-treated mice with periodontal disease and explore the role of rosiglitazone, a drug that has been reported to lower the M1/M2 macrophage ratio, in MRONJ burden. Mice received ZA, and experimental periodontal disease (EPD) was induced around their second left maxillary molar. The mice were euthanized 1, 2, or 4 wk later. Micro-computed tomography and histologic and immunohistochemical analyses were carried out. In a separate experiment, mice were treated with ZA in the absence or presence of rosiglitazone, EPD was induced for 5 wk, and the MRONJ burden was assessed. An M1 predilection was noted in ZA versus vehicle (Veh) mice at 1, 2, or 4 wk after ligature placement. M1 cells were found to be positive for MMP-13, and their presence coincided with disruption of the surrounding collagen network in ZA mice. Rosiglitazone caused a reversal in the M1/M2 polarization in Veh and ZA mice. Rosiglitazone did not cause significant radiographic changes 5 wk after EPD in Veh or ZA animals. Importantly, percentage osteonecrosis and bone exposure were decreased in the rosiglitazone-treated versus nontreated ZA sites 5 wk after EPD. Our data point to an important role of M1 macrophage polarization with an overexpression of MMP-13 in the early phases of MRONJ development and provide insight into the use of interventional approaches promoting an M2 phenotype as a preventative means to alleviate MRONJ burden., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Osteoporosis-pseudoglioma syndrome (OPPG) and LRP5 high bone mass (LRP5-HBM) are two rare bone diseases with opposite clinical symptoms caused by loss-of-function and gain-of-function mutations in LRP5. Bisphosphonates are an effective treatment for OPPG patients. LRP5-HBM has a benign course, and age-related bone loss is found in one LRP5-HBM patient., Purpose: Low-density lipoprotein receptor-related protein 5 (LRP5) is involved in the canonical Wnt signaling pathway. The gain-of-function mutation leads to high bone mass (LRP5-HBM), while the loss-of-function mutation leads to osteoporosis-pseudoglioma syndrome (OPPG). In this study, the clinical manifestations, disease-causing mutations, treatment, and follow-up were summarized to improve the understanding of these two diseases., Methods: Two OPPG patients and four LRP5-HBM patients were included in this study. The clinical characteristics, biochemical and radiological examinations, pathogenic mutations, and structural analysis were summarized. Furthermore, several patients were followed up to observe the treatment effect and disease progress., Results: Congenital blindness, persistent bone pain, low bone mineral density (BMD), and multiple brittle fractures were the main clinical manifestations of OPPG. Complex heterozygous mutations were detected in two OPPG patients. The c.1455G > T mutation in exon 7 was first reported. During the follow-up, BMD of two patients was significantly improved after bisphosphonate treatment. On the contrary, typical clinical features of LRP5-HBM included extremely high BMD without fractures, torus palatinus and normal vision. X-ray showed diffuse osteosclerosis. Two heterozygous missense mutations were detected in four patients. In addition, age-related bone loss was found in one LRP5-HBM patient after 12-year of follow-up., Conclusion: This study deepened the understanding of the clinical characteristics, treatment, and follow-up of OPPG and LRP5-HBM; expanded the pathogenic gene spectrum of OPPG; and confirmed that bisphosphonates were effective for OPPG. Additionally, it was found that Ala242Thr mutation could not protect LRP5-HBM patients from age-related bone loss. This phenomenon deserves further study., (© 2024. The Author(s).)

Currently available biotherapeutics for the treatment of osteoporosis lack explicit mechanisms for bone localization, potentially limiting efficacy and inducing off-target toxicities. While various strategies have been explored for targeting the bone surface, critical aspects remain poorly understood, including the optimal affinity ligand, the role of binding avidity and circulation time, and, most importantly, whether or not this strategy can enhance the functional activity of clinically relevant protein therapeutics. To investigate, we generated fluorescent proteins (eg, mCherry) with site-specifically attached small molecule (bisphosphonate) or peptide (deca-aspartate, D10) affinity ligands. While both affinity ligands successfully anchored fluorescent protein to the bone surface, quantitative radiotracing revealed only modest femoral and vertebral accumulation and suggested a need for enhanced circulation time. To achieve this, we fused mCherry to the Fc fragment of human IgG1 and attached D10 peptides to each C-terminus. The mCherry-Fc-D10 demonstrated an ~80-fold increase in plasma exposure and marked increases in femoral and vertebral accumulation (13.6% ± 1.4% and 11.4% ± 1.3% of the injected dose/g [%ID/g] at 24 h, respectively). To determine if bone surface targeting could enhance the efficacy of a clinically relevant therapeutic, we generated a bone-targeted sclerostin-neutralizing antibody, anti-sclerostin-D10. The targeted antibody demonstrated marked increases in bone accumulation and retention (20.9 ± 2.5% and 19.5 ± 2.5% ID/g in femur and vertebrae at 7 days) and enhanced effects in a murine model of ovariectomy-induced bone loss (bone volume/total volume, connectivity density, and structure model index all increased [P < .001] vs untargeted anti-sclerostin). Collectively, our results indicate the importance of both bone affinity and circulation time in achieving robust targeting of therapeutic proteins to the bone surface and suggest that this approach may enable lower doses and/or longer dosing intervals without reduction in biotherapeutic efficacy. Future studies will be needed to determine the translational potential of this strategy and its potential impact on off-site toxicities., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: To evaluate collagen fibers during the bone repair process in critical defects created in the tibias of rats, treated with zoledronic acid (AZ) associated with low-level laser therapy (LLLT)., Methods: Ten rats were distributed according to treatment: group 1) saline solution; group 2) LLLT; group 3) AZ; group 4) AZ and LLLT. AZ was administered at the dose of 0.035 mg/kg at fortnightly intervals over eight weeks. Next, 2-mm bone defects were created in the tibias of all animals. The bone defects in groups 2 and 4 were irradiated LLLT in the immediate postoperative period. After periods 14 and 28 of application, the animals were euthanized, and birefringence analysis was performed., Results: Approximately 90% of the total area was occupied by collagen fibers within the red color spectrum, this area being statistically larger in relation to the area occupied by collagen fibers within the green and yellow spectrum, in the four groups. Over the 14-day period, there was no statistically significant difference between the groups. In the 28-day period, group 2 (14.02 ± 15.9%) was superior in quantifying green birefringent fibers compared to group 1 (3.06 ± 3.24%), with p = 0.009., Conclusions: LLLT associated with ZA is effective in stimulating the neoformation of collagen fibers. The LLLT group without the association with ZA showed a greater amount of immature and less organized matrix over a period of 28 days.

Objectives: Osteoporosis animal models are used extensively to determine the mechanisms of disease pathology and identify potential biological targets. The study aimed to establish a bone loss model, identify pain-related behaviour in neighbouring joints using an adjuvant-induced osteoporosis model, and examine the therapeutic effect of bisphosphonates., Methods: Complete Freund's adjuvant was injected subcutaneously into the back of the right foot of 8-week-old female ddY mice. Subsequently, pain, arthritis, and bone density in the right knee were monitored over time., Results: Pain evaluation using von Frey filaments showed a significantly exacerbated knee pain threshold compared to the control group (saline administration) at 7- and 14-day intervals after complete Freund's adjuvant administration, and bone density during the same period also significantly declined. The adjuvant-induced osteoporosis model was created similarly; alendronate 40 μg/kg was subcutaneously injected twice and vehicle once from 7 to 14 days after onset. In the alendronate administration group on the 14th day, significant improvements in bone density, arthritis, and pain threshold around the knee were observed compared to the untreated group., Conclusions: Alendronate may contribute to pain improvement through the simultaneous effects of bone mass improvement and suppression of osteoporotic pain., (© Japan College of Rheumatology 2024. Published by Oxford University Press. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

The primary focus of bisphosphonate medications is on targeting human farnesyl pyrophosphate synthase (hFPPS), an essential regulator of mammalian isoprenoids. Yet, these drugs encounter limitations due to their restricted "druglike" properties and their effectiveness primarily in treating skeletal disorders. In this study, we synthesized novel non-bisphosphonate compounds, using 4,4'-(ethane-1,2-diylbis(oxy))bis(3-methoxybenzaldehyde) (1) as a starting compound, with the aim of targeting hFPPS through a mixed binding approach. Among the various compounds tested, compounds 4a and 4b exhibited significant inhibition of hFPPS activity, with IC 50 values of 1.108 and 1.24 μM, respectively. Docking studies further revealed that both compounds bound within the allylic binding site and near the isopentenyl diphosphate (IPP) site within the hFPPS pocket. Molecular dynamic simulations were performed on the best docking pose of the most potent compound 4a to confirm the formation of a stable complex with hFPPS. In an in vivo study conducted on ovariectomized rats, various biochemical markers including osteocalcin, estradiol, osteoprotegerin, bone mineral content, and density were negatively impacted, while levels of bone specific alkaline phosphatase, receptor activator of nuclear factor kappa-Β ligand, serum/urinary calcium, and phosphate increased. Notably, compound 4a exhibited antiresorptive properties similar to zoledronate, effectively restoring most of the perturbed biochemical estimations. These findings suggest the potential of compound 4a, a non-bisphosphonate compound, as alternative therapeutic agents for combating osteoporosis., Competing Interests: Declaration of competing interest We confirm that this work is original, was not published elsewhere, and is not currently under consideration for publication. We have no conflicts of interest to declare., (Copyright © 2024. Published by Elsevier Masson SAS.)

This study introduces a novel 3D scaffold for bone regeneration, composed of silk fibroin, chitosan, nano-hydroxyapatite, LL-37 antimicrobial peptide, and pamidronate. The scaffold addresses a critical need in bone tissue engineering by simultaneously combating bone infections and promoting bone growth. LL-37 was incorporated for its broad-spectrum antimicrobial properties, while pamidronate was included to inhibit bone resorption. The scaffold's porous structure, essential for cell infiltration and nutrient diffusion, was achieved through a freeze-drying process. In vitro assessments using SEM and FTIR confirmed the scaffold's morphology and chemical integrity. Antimicrobial efficacy was tested against pathogens of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). In vivo studies in a murine model of infectious bone defect revealed the scaffold's effectiveness in reducing inflammation and bacterial load, and promoting bone regeneration. RNA sequencing of treated specimens provided insights into the molecular mechanisms underlying these observations, revealing significant gene expression changes related to bone healing and immune response modulation. The results indicate that the scaffold effectively inhibits bacterial growth and supports bone cell functions, making it a promising candidate for treating infectious bone defects. Future studies should focus on optimizing the release of therapeutic agents and evaluating the scaffold's clinical potential., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Osteonecrosis of the jaw (ONJ) is a relatively rare side effect after prolonged use of bisphosphonates, which are drugs used to treat bone resorption in osteoporosis and certain cancers. This study introduces a novel ONJ model in rats by combining exposure to bisphosphonates, oral surgery, and bacterial inoculation. Potential ONJ preventive effects of polyguanidine (GuaDex) or antibiotics were evaluated. The study consisted of twenty-four male Wistar rats were divided into four groups. Groups 1 to 3 were given weekly doses of i.v. Zoledronic acid (ZA), four weeks before and two weeks after an osteotomy procedure on their left mandibular first molar. Group 4 was a negative control. Streptococcus gordonii bacteria were introduced into the osteotomy pulp chamber and via the food for seven days. On day eight, the rats were given different treatments. Group 1 was given a GuaDex injection into the osteotomy socket, Group 2 was given an intramuscular (i.m.) injection of clindamycin, Group 3 (positive control) was given an i.m. injection of saline, and Group 4 was given an i.m. injection of saline. Blood samples were taken two weeks after the osteotomy procedure, after which the rats were euthanized. Bone healing, bone mineral density, histology, and blood status were analyzed. The results showed that Group 1 (GuaDex) had no ONJ, extensive ongoing bone regeneration, active healing activity, vascularization, and no presence of bacteria. Group 2 (clindamycin) showed early stages of ONJ, avascular areas, and bacteria. Group 3 showed stages of ONJ, inflammatory infiltrates, defective healing, and bacterial presence, and Group 4 had normal healing activity and no bacterial presence. Conclusion: ZA treatment and bacterial inoculation after tooth extraction inhibited bone remodeling/healing and induced ONJ characteristic lesions in the rats. Only GuaDex apparently prevented ONJ development, stimulated bone remodeling, and provided an antimicrobial effect., Competing Interests: Declaration of competing interest The authors stated that they have no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Bone resorption inhibitors, such as bisphosphonates (BP) and denosumab, are frequently used for the management of osteoporosis. Although both drugs reduce the risk of osteoporotic fractures, they are associated with a serious side effect known as medication-related osteonecrosis of the jaw (MRONJ). Sclerostin antibodies (romosozumab) increase bone formation and decrease the risk of osteoporotic fractures: however, their anti-resorptive effect increases ONJ. Thus, this study aimed to elucidate the role of sclerostin deletion in the development of MRONJ., Methods: Sclerostin knockout (Sost Δ26/Δ26 ) mice were used to confirm the development of ONJ by performing tooth extractions. To confirm the role of sclerostin deficiency in a more ONJ-prone situation, we used the BP-induced ONJ model in combination with severe periodontitis to evaluate the development of ONJ and bone formation in wild-type (WT) and Sost Δ26/Δ26 mice. Wound healing assay using gingival fibroblasts with or without sclerostin stimulation and tooth extraction socket healing were evaluated in the WT and Sost Δ26/Δ26 mice., Results: ONJ was not detected in the extraction socket of Sost Δ26/Δ26 mice. Moreover, the incidence of ONJ was significantly lower in the Sost Δ26/Δ26 mice treated with BP compared to that of the WT mice. Osteogenic proteins, osteocalcin, and runt-related transcription factor 2, were expressed in the bone surface in Sost Δ26/Δ26 mice. Recombinant sclerostin inhibited gingival fibroblast migration. The wound healing rate of the extraction socket was faster in Sost Δ26/Δ26 mice than in WT mice., Conclusion: Sclerostin deficiency did not cause ONJ and reduced the risk of developing BP-induced ONJ. Enhanced bone formation and wound healing were observed in the tooth extraction socket. The use of romosozumab (anti-sclerostin antibody) has proven to be safe for surgical procedures of the jaw., Competing Interests: Declaration of competing interest There are no conflicts of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: The effects of daily teriparatide (D-PTH, 20 μg/day), weekly high-dose teriparatide (W-PTH, 56.5 μg/week), or bisphosphonate (BP) on the vertebra and proximal femur were investigated using quantitative computed tomography (QCT)., Methods: A total of 131 postmenopausal women with a history of fragility fractures were randomized to receive D-PTH, W-PTH, or bisphosphonate (oral alendronate or risedronate). QCT were evaluated at baseline and after 18 months of treatment., Results: A total of 86 participants were evaluated by QCT (Spine: D-PTH: 25, W-PTH: 21, BP: 29. Hip: PTH: 22, W-PTH: 21, BP: 32. Dropout rate: 30.5 %). QCT of the vertebra showed that D-PTH, W-PTH, and BP increased total vBMD (+34.8 %, +18.2 %, +11.1 %), trabecular vBMD (+50.8 %, +20.8 %, +12.2 %), and marginal vBMD (+20.0 %, +14.0 %, +11.5 %). The increase in trabecular vBMD was greater in the D-PTH group than in the W-PTH and BP groups. QCT of the proximal femur showed that D-PTH, W-PTH, and BP increased total vBMD (+2.8 %, +3.6 %, +3.2 %) and trabecular vBMD (+7.7 %, +5.1 %, +3.4 %), while only W-PTH and BP significantly increased cortical vBMD (-0.1 %, +1.5 %, +1.6 %). Although there was no significant increase in cortical vBMD in the D-PTH group, cortical bone volume (BV) increased in all three treatment groups (+2.1 %, +3.6 %, +3.1 %)., Conclusions: D-PTH had a strong effect on trabecular bone of vertebra. Although D-PTH did not increase cortical BMD of proximal femur, it increased cortical BV. W-PTH had a moderate effect on trabecular bone of vertebra, while it increased both cortical BMD and BV of proximal femur. Although BP had a limited effect on trabecular bone of vertebra compared to teriparatide, it increased both cortical BMD and BV of proximal femur., Competing Interests: Declaration of competing interest This study was supported by Asahi Kasei Pharma Corporation and Eli Lilly Japan K.K., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Superficial infections of the skin, hair, and nails by fungal dermatophytes are the most prevalent of human mycoses, and many infections are refractory to treatment. As current treatment options are limited, recent research has explored drug synergy with azoles for dermatophytoses. Bisphosphonates, which are approved to treat osteoporosis, can synergistically enhance the activity of azoles in diverse yeast pathogens but their activity has not been explored in dermatophytes or other molds. Market bisphosphonates risedronate, alendronate, and zoledronate (ZOL) were evaluated for antifungal efficacy and synergy with three azole antifungals: fluconazole (FLC), itraconazole (ITR), and ketoconazole (KET). ZOL was the most active bisphosphonate tested, displaying moderate activity against nine dermatophyte species (MIC range 64-256 µg/mL), and was synergistic with KET in eight of these species. ZOL was also able to synergistically improve the anti-biofilm activity of KET and combining KET and ZOL prevented the development of antifungal resistance. Rescue assays in Trichophyton rubrum revealed that the inhibitory effects of ZOL alone and in combination with KET were due to the inhibition of squalene synthesis. Fluorescence microscopy using membrane- and ROS-sensitive probes demonstrated that ZOL and KET:ZOL compromised membrane structure and induced oxidative stress. Antifungal activity and synergy between bisphosphonates and azoles were also observed in other clinically relevant molds, including species of Aspergillus and Mucor . These findings indicate that repurposing bisphosphonates as antifungals is a promising strategy for revitalising certain azoles as topical antifungals, and that this combination could be fast-tracked for investigation in clinical trials., Importance: Fungal infections of the skin, hair, and nails, generally grouped together as "tineas" are the most prevalent infectious diseases globally. These infections, caused by fungal species known as dermatophytes, are generally superficial, but can in some cases become aggressive. They are also notoriously difficult to resolve, with few effective treatments and rising levels of drug resistance. Here, we report a potential new treatment that combines azole antifungals with bisphosphonates. Bisphosphonates are approved for the treatment of low bone density diseases, and in fungi they inhibit the biosynthesis of the cell membrane, which is also the target of azoles. Combinations were synergistic across the dermatophyte species and prevented the development of resistance. We extended the study to molds that cause invasive disease, finding synergy in some problematic species. We suggest bisphosphonates could be repurposed as synergents for tinea treatment, and that this combination could be fast-tracked for use in clinical therapy., Competing Interests: The authors declare no conflict of interest.

Candidiasis places a significant burden on human health and can range from common superficial vulvovaginal and oral infections to invasive diseases with high mortality. The most common Candida species implicated in human disease is Candida albicans , but other species like Candida glabrata are emerging. The use of azole antifungals for treatment is limited by increasing rates of resistance. This study explores repositioning bisphosphonates, which are traditionally used for osteoporosis, as antifungal synergists that can improve and revitalize the use of azoles. Risedronate, alendronate, and zoledronate (ZOL) were tested against isolates from six different species of Candida , and ZOL produced moderate antifungal activity and strong synergy with azoles like fluconazole (FLC), particularly in C. glabrata . FLC:ZOL combinations had increased fungicidal and antibiofilm activity compared to either drug alone, and the combination prevented the development of antifungal resistance. Mechanistic investigations demonstrated that the synergy was mediated by the depletion of squalene, resulting in the inhibition of ergosterol biosynthesis and a compromised membrane structure. In C. glabrata , synergy compromised the function of membrane-bound multidrug transporters and caused an accumulation of reactive oxygen species, which may account for its acute sensitivity to FLC:ZOL. The efficacy of FLC:ZOL in vivo was confirmed in a Galleria mellonella infection model, where combinations improved the survival of larvae infected with C. albicans and C. glabrata to a greater extent than monotherapy with FLC or ZOL, and at reduced dosages. These findings demonstrate that bisphosphonates and azoles are a promising new combination therapy for the treatment of topical candidiasis., Importance: Candida is a common and often very serious opportunistic fungal pathogen. Invasive candidiasis is a prevalent cause of nosocomial infections with a high mortality rate, and mucocutaneous infections significantly impact the quality of life of millions of patients a year. These infections pose substantial clinical challenges, particularly as the currently available antifungal treatment options are limited in efficacy and often toxic. Azoles are a mainstay of antifungal therapy and work by targeting the biosynthesis of ergosterol. However, there are rising rates of acquired azole resistance in various Candida species, and some species are considered intrinsically resistant to most azoles. Our research demonstrates the promising therapeutic potential of synergistically enhancing azoles with non-toxic, FDA-approved bisphosphonates. Repurposing bisphosphonates as antifungal synergists can bypass much of the drug development pipeline and accelerate the translation of azole-bisphosphonate combination therapy., Competing Interests: The authors declare no conflict of interest.

As multiple myeloma (MM) progresses, immune effector cells decrease in number and function and become exhausted. This remains an insurmountable clinical issue that must be addressed by development of novel modalities to revitalize anti-MM immunity. Human Vγ9Vδ2 T (Vδ2 + γδ T) cells serve as the first line of defense against pathogens as well as tumors and can be expanded ex vivo from peripheral blood mononuclear cells (PBMCs) upon treatment with amino-bisphosphonates in combination with IL-2. Here, we demonstrated that next-generation immunomodulators called cereblon E3 ligase modulators (CELMoDs), as well as lenalidomide and pomalidomide, expanded Th1-like Vδ2 + γδ T cells from PBMCs in the presence of zoledronic acid (ZA). However, the expansion of Th1-like Vδ2 + γδ T cells by these immunomodulatory drugs was abolished under IL-2 blockade, although IL-2 production was induced in PBMCs. BTN3A1 triggers phosphoantigen presentation to γδ T-cell receptors and is required for γδ T-cell expansion and activation. ZA but not these immunomodulatory drugs upregulated BTN3A1 in monocytes. These results suggest that immunomodulatory drugs and ZA have cooperative roles in expansion of Th1-like Vδ2 + γδ T cells, and provide the important knowledge for clinical application of human Vδ2 + γδ T cells as effector cells., (© 2024. Japanese Society of Hematology.)

Bisphosphonate-related osteonecrosis of jaw (BRONJ) is characterized by impaired osteogenic differentiation of orofacial bone marrow stromal cells (BMSCs). Corin has recently been demonstrated to act as a key regulator in bone development and orthopedic disorders. However, the role of corin in BRONJ-related BMSCs dysfunction remains unclarified. A m6A epitranscriptomic microarray study from our group shows that the CORIN gene is significantly upregulated and m6A hypermethylated during orofacial BMSCs osteogenic differentiation. Corin knockdown inhibits BMSCs osteogenic differentiation, whereas corin overexpression or soluble corin (sCorin) exerts a promotion effect. Furthermore, corin expression is negatively regulated by bisphosphonates (BPs). Corin overexpression or sCorin reverses BPs-impaired BMSCs differentiation ability. Mechanistically, we find altered expression of phos-ERK in corin knockdown/overexpression BMSCs and BMSCs under sCorin stimulation. PD98059 (a selective ERK inhibitor) blocks the corin-mediated promotion effect. With regard to the high methylation level of corin during osteogenic differentiation, we apply a non-selective m6A methylase inhibitor, Cycloleucine, which also blocks the corin-mediated promotion effect. Furthermore, we demonstrate that METTL7A modulates corin m6A modification and reverses BPs-impaired BMSCs function, indicating that METTL7A regulates corin expression and thus contributes to orofacial BMSCs differentiation ability. To conclude, our study reveals that corin reverses BPs-induced BMSCs dysfunction, and METTL7A-mediated corin m6A modification underlies corin promotion of osteogenic differentiation via the ERK pathway. We hope this brings new insights into future clinical treatments for BRONJ., (© 2024. The Author(s).)

Titanium (Ti) is widely utilized as an implant material; nonetheless, its integration with bone tissue faces limitations due to a patient's comorbidities. To address this challenge, we employed a strategic approach involving the growth of thin films by spin-coating and surface functionalization with etidronate (ETI), alendronate (ALE), and risedronate (RIS). Our methodology involved coating of Ti cp IV disks with thin films of TiO2, hydroxyapatite (HA), and their combinations (1:1 and 1:2 v/v), followed by surface functionalization with ETI, ALE, and RIS. Bisphosphonate-doped films were evaluated in terms of surface morphology and physical-chemical properties by techniques such as electron microscopy, confocal microscopy, and x-ray photoelectron spectroscopy. The antibacterial potential of bisphosphonates alone or functionalized onto the Ti surface was tested against Staphylococcus aureus biofilms. Primary human bone mesenchymal stem cells were used to determine in vitro cell metabolism and mineralization. Although RIS alone did not demonstrate any antibacterial effect as verified by minimum inhibitory concentration assay, when Ti surfaces were functionalized with RIS, partial inhibition of Staphylococcus aureus growth was noted, probably because of the physical-chemical surface properties. Furthermore, samples comprising TiO2/HA (1:1 and 1:2 v/v) showcased an enhancement in the metabolism of nondifferentiated cells and can potentially enhance the differentiation of osteoblastic precursors. All samples demonstrated cell viability higher than 80%. Addition of hydroxyapatite and presence of bisphosphonates increase the metabolic activity and the mineralization of human bone mesenchymal cells. While these findings hold promise, it is necessary to conduct further studies to evaluate the system's performance in vivo and ensure its long-term safety. This research marks a significant stride toward optimizing the efficacy of titanium implants through tailored surface modifications., (2024 Published under an exclusive license by the AVS.)

Bone cancer is common and severe. Both primary (e.g., osteosarcoma, Ewing sarcoma) and secondary (e.g., metastatic) bone cancers lead to significant health problems and death. Currently, treatments such as chemotherapy, hormone therapy, and radiation therapy are used to treat bone cancer, but they often only shrink or slow tumor growth and do not eliminate cancer completely. The bone microenvironment contributes unique signals that influence cancer growth, immunogenicity, and metastasis. Traditional cancer therapies have limited effectiveness due to off-target effects and poor distribution on bones. As a result, therapies with improved specificity and efficacy for treating bone tumors are highly needed. One of the most promising strategies involves the targeted delivery of pharmaceutical agents to the site of bone cancer by introduction of bone-targeting moieties, such as bisphosphonates or oligopeptides. These moieties have high affinities to the bone hydroxyapatite matrix, a structure found exclusively in skeletal tissue, and can enhance the targeting ability and efficacy of anticancer drugs when combating bone tumors. This review focuses on the engineering of small molecules and proteins with bone-targeting moieties for the treatment of bone tumors., Competing Interests: Declaration of interests X.Z., and H.X. are inventors of patents titled “Bone-specific delivery of polypeptides (EP4281116A1),” “Engineered compositions for bone-targeted therapy (WO2023004348A1),” and “Methods for controlling osteocalcin release (WO2023064802A1).” J.M.B. serves as the Chief Executive Officer of Osteologic Therapeutics, Inc. X.Z., and H.X. are cofounders and Scientific Advisory Board members of Osteologic Therapeutics, Inc., (Copyright © 2024 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate whether antimicrobial photodynamic therapy (aPDT) repairs bisphosphonate-related osteonecrosis of the jaw (BRONJ) modulated by the reduction of NF-kB protein in a murine model., Methodology: Male Wistar rats (N=30) were divided into the following groups (n=6/group): negative control (NC); experimental osteonecrosis (ONE); ONE + photosensitizer (PS); ONE + photobiomodulation (PBM); and ONE + aPDT. Over 8 weeks, ONE was induced by zoledronic acid 250 µg/kg injections, except in the NC group, which received sterile 0.9% saline, followed by extraction of the lower left first molar. Red light laser irradiation (wavelength ~660 nm, power 50 mW, energy of 2 J, energy dose of 66.67 J/cm2 for 40 s) was performed once a week for 4 weeks. Methylene blue 0.3% was used as PS. The animals were euthanized and examined macroscopically for the presence of exposed bone and epithelial repair and microscopically by histochemical (hematoxylin-eosin and Masson's trichrome staining) and immunohistochemical (anti-NF-kB) methods. Macroscopic and histomorphometric data were analyzed by one-way ANOVA and Tukey's post-test (p<0.05)., Results: Mucosal repair, viable osteocytes, and NF-kB immunostaining were observed in the NC, ONE+PS, ONE+PBM, and ONE+aPDT groups. The ONE group showed no mucosal repair, showing empty lacunae and multifocal immunostaining for NF-kB. The ONE+PBM and ONE+aPDT groups had greater deposition of extracellular matrix and less necrotic bone tissue (p<0.05)., Conclusion: PBM and aPDT treatments for BRONJ were effective for bone and epithelial repair, in addition to reducing inflammation mediated by the decrease of NF-kB protein in the irradiated regions.

Bisphosphonates are commonly used to treat and prevent bone loss, but their effects in active, juvenile populations are unknown. This study examined the effects of intramuscular clodronate disodium (CLO) on bone turnover, serum bone biomarkers (SBB), bone mineral density (BMD), bone microstructure, biomechanical testing (BT), and cartilage glycosaminoglycan content (GAG) over 165 days. Forty juvenile sheep (253 ± 6 days of age) were divided into four groups: Control (saline), T0 (0.6 mg/kg CLO on day 0), T84 (0.6 mg/kg CLO on day 84), and T0+84 (0.6 mg/kg CLO on days 0 and 84). Sheep were exercised 4 days/week and underwent physical and lameness examinations every 14 days. Blood samples were collected for SBB every 28 days. Microstructure and BMD were calculated from tuber coxae (TC) biopsies (days 84 and 165) and bone healing was assessed by examining the prior biopsy site. BT and GAG were evaluated postmortem. Data, except lameness data, were analyzed using a mixed-effects model; lameness data were analyzed as ordinal data using a cumulative logistic model. CLO did not have any measurable effects on the skeleton of sheep. SBB showed changes over time (p ≤ 0.03), with increases in bone formation and decreases in some bone resorption markers. TC biopsies showed increasing bone volume fraction, trabecular spacing and thickness, and reduced trabecular number on day 165 versus day 84 (p ≤ 0.04). These changes may be attributed to exercise or growth. The absence of a treatment effect may be explained by the lower CLO dose used in large animals compared to humans. Further research is needed to examine whether low doses of bisphosphonates may be used in active juvenile populations for analgesia without evidence of bone changes., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Vergara-Hernandez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Fracture fixation in an ageing population is challenging and fixation failure increases mortality and societal costs. We report a novel fracture fixation treatment by applying a hydroxyapatite (HA) based biomaterial at the bone-implant interface and biologically activating the biomaterial by systemic administration of a bisphosphonate (zoledronic acid, ZA). We first used an animal model of implant integration and applied a calcium sulphate (CaS)/HA biomaterial around a metallic screw in the tibia of osteoporotic rats. Using systemic ZA administration at 2-weeks post-surgery, we demonstrated that the implant surrounded by HA particles showed significantly higher peri‑implant bone formation compared to the unaugmented implants at 6-weeks. We then evaluated the optimal timing (day 1, 3, 7 and 14) of ZA administration to achieve a robust effect on peri‑implant bone formation. Using fluorescent ZA, we demonstrated that the uptake of ZA in the CaS/HA material was the highest at 3- and 7-days post-implantation and the uptake kinetics had a profound effect on the eventual peri‑implant bone formation. We furthered our concept in a feasibility study on trochanteric fracture patients randomized to either CaS/HA augmentation or no augmentation followed by systemic ZA treatment. Radiographically, the CaS/HA group showed signs of increased peri‑implant bone formation compared with the controls. Finally, apart from HA, we demonstrated that the concept of biologically activating a ceramic material by ZA could also be applied to β-tricalcium phosphate. This novel approach for fracture treatment that enhances immediate and long-term fracture fixation in osteoporotic bone could potentially reduce reoperations, morbidity and mortality. STATEMENT OF SIGNIFICANCE: • Fracture fixation in an ageing population is challenging. Biomaterial-based augmentation of fracture fixation devices has been attempted but lack of satisfactory biological response limits their widespread use. • We report the biological activation of locally implanted microparticulate hydroxyapatite (HA) particles placed around an implant by systemic administration of the bisphosphonate zoledronic acid (ZA). The biological activation of HA by ZA enhances peri‑implant bone formation. •Timing of ZA administration after HA implantation is critical for optimal ZA uptake and consequently determines the extent of peri‑implant bone formation. • We translate the developed concept from small animal models of implant integration to a proof-of-concept clinical study on osteoporotic trochanteric fracture patients. • ZA based biological activation can also be applied to other calcium phosphate biomaterials., Competing Interests: Declaration of competing interest D.B.R., L.L., M.T. and Y.L. are shareholders in Moroxite AB and Moroxite F AB, Lund, Sweden. All other authors have nothing to disclose. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lars Lidgren, Deepak Bushan Raina, and Magnus Tägil have received funding from the Olav-Thon Foundation. Deepak Bushan Raina has received funding from the Crafoord Foundation, the Maggie-Stephens Foundation, the Royal Physiographic Society Lund, the Sten K Johnson Foundation. Magnus Tägil, Hanna Isaksson and Yang Liu received funding from VINNOVA to conduct neutron tomography experiments. Deepak Bushan Raina, Lars Lidgren, Magnus Tägil and Yang Liu are shareholders in Moroxite AB and Moroxite F AB, Lund, Sweden. All other authors have nothing to disclose., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The antitumoral activity of hydroxymethylene bisphosphonates (HMBP) such as alendronate or zoledronate is hampered by their exceptional bone-binding properties and their short plasmatic half-life which preclude their accumulation in non-skeletal tumors. In this context, the use of lipophilic prodrugs represents a simple and straightforward strategy to enhance the biodistribution of bisphosphonates in these tissues. We describe in this article the synthesis of light-responsive prodrugs of HMBP alendronate. These prodrugs include lipophilic photo-removable nitroveratryl groups which partially mask the highly polar alendronate HMBP scaffold. Photo-responsive prodrugs of alendronate are stable in physiological conditions and display reduced toxicity compared to alendronate against MDA-MB-231 cancer cells. However, the antiproliferative effect of these prodrugs is efficiently restored after cleavage of their nitroveratryl groups upon exposure to UV light. In addition, substitution of alendronate with such photo-responsive substituents drastically reduces its bone-binding properties, thereby potentially improving its biodistribution in soft tissues after i.v. administration. The development of such lipophilic photo-responsive prodrugs is a promising approach to fully exploit the anticancer effect of HMBPs on non-skeletal tumors., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lecouvey Marc reports was provided by Sorbonne North Paris University. Marc Lecouvey reports a relationship with Sorbonne North Paris University that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Objective : This study aims to explore the preventive potential of photobiomodulation (PBM) in bisphosphonate-related osteonecrosis of the jaw (BRONJ) using a rat model. Methods : An experimental rat model was established, exposing rats to zoledronic acid (ZA), a primary risk factor for BRONJ. An 810 nm diode laser was applied with parameters of 0.33 W/cm 2 power density and 10 J/cm 2 energy density for 30 sec. PBM was initiated 1 day pre-extraction and continued for 2 weeks. The impact of PBM on wound healing in both soft and hard tissues was evaluated post tooth extraction. Results : ZA exposure hindered wound healing in both soft and hard tissues after tooth extraction. PBM intervention effectively mitigated the adverse effects of ZA, promoting healing processes in both tissue types. This suggests the potential of PBM as a preventive strategy for BRONJ in patients on long-term bisphosphonate treatment. Moreover, PBM exhibited enhanced wound healing in normal rats, indicating its broader applicability beyond BRONJ cases. Conclusions : PBM shows promise in preventing and improving wound healing in BRONJ and normal cases. These findings underscore the significance of optimizing PBM parameters and suggest its potential clinical relevance as a preventive intervention for BRONJ and a promoter of wound healing.

This study evaluated the effect of resveratrol (RES) on the prevention of medication-related osteonecrosis of the jaws (MRONJ) in ovariectomized (OVX) rats treated with zoledronate (ZOL). Fifty rats were distributed in five groups: SHAM (n = 10): non-ovariectomy + placebo; OVX (n = 10):ovariectomy + placebo; OVX + RES (n = 10):ovariectomy + resveratrol; OVX + ZOL (n = 10):ovariectomy + placebo + zoledronate; and OVX + RES + ZOL (n = 10):ovariectomy + resveratrol + zoledronate. The mandibles left sides were analyzed with micro-CT, histomorphometry, and immunohistochemistry. On the right side, bone markers gene expression was analyzed by qPCR. ZOL increased the percentage of necrotic bone and reduced the neo-formed bone compared to groups not receiving ZOL (p < 0.05). RES impacted the tissue healing pattern in OVX + ZOL + RES, reduced inflammatory cell infiltrate, and improved bone formation in the extraction site. Osteoblasts, alkaline phosphatase (ALP)-, and osteocalcin (OCN)-immunoreactive cells were lower in OVX-ZOL than in SHAM, OVX, and OVX-RES. The OXV-ZOL-RES had fewer osteoblasts and ALP- and OCN-cells than the SHAM and OVX-RES. The tartrate-resistant acid phosphatase (TRAP)-positive cells were reduced in the presence of ZOL (p < 0.05), while the TRAP mRNA levels increased with ZOL treatment, with or without resveratrol, compared with the other groups (p < 0.05). RES alone increased superoxide dismutase levels compared to OVX + ZOL and OVX + ZOL + RES (p < 0.05). In conclusion, resveratrol reduced the tissue impairment severity induced by ZOL; however, it could not prevent the occurrence of MRONJ., (© 2023 Wiley Periodicals LLC.)

Depletion of cellular levels of geranylgeranyl diphosphate by inhibition of the enzyme geranylgeranyl diphosphate synthase (GGDPS) is a potential strategy for disruption of protein transport by limiting the geranylgeranylation of the Rab proteins that regulate intracellular trafficking. As such, there is interest in the development of GGDPS inhibitors for the treatment of malignancies characterized by abnormal protein production, including multiple myeloma. Our previous work has explored the structure-function relationship of a series of isoprenoid triazole bisphosphonate-based GGDPS inhibitors, with modifications having impact on enzymatic, cellular and in vivo activities. We have synthesized a new series of α-amino bisphosphonates to understand the impact of modifying the alpha position with a moiety that is potentially linkable to other agents. Bioassays evaluating the enzymatic and cellular activities of these compounds demonstrate that incorporation of the α-amino group affords compounds with GGDPS inhibitory activity which is modulated by isoprenoid tail chain length and olefin stereochemistry. These studies provide further insight into the complexity of the structure-function relationship and will enable future efforts focused on tumor-specific drug delivery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: Osteoporosis is a global health issue. Bisphosphonates that are commonly used to treat osteoporosis suppress both bone resorption and subsequent bone formation. Inhibition of cathepsin K, a cysteine proteinase secreted by osteoclasts, was reported to suppress bone resorption while preserving or increasing bone formation. Analyses of the different effects of antiresorptive reagents such as bisphosphonates and cysteine proteinase inhibitors will contribute to the understanding of the mechanisms underlying bone remodeling., Materials and Methods: Our team has developed an in vitro system in which bone remodeling can be temporally observed at the cellular level by 2-photon microscopy. We used this system in the present study to examine the effects of the cysteine proteinase inhibitor E-64 and those of zoledronic acid on bone remodeling., Results: In the control group, the amount of the reduction and the increase in the matrix were correlated in each region of interest, indicating the topological and quantitative coordination of bone resorption and formation. Parameters for osteoblasts, osteoclasts, and matrix resorption/formation were also correlated. E-64 disrupted the correlation between resorption and formation by potentially inhibiting the emergence of spherical osteoblasts, which are speculated to be reversal cells in the resorption sites., Conclusion: These new findings help clarify coupling mechanisms and will contribute to the development of new drugs for osteoporosis., (© 2024. The Author(s).)

Postmenopausal osteoporosis arises from imbalanced osteoclast and osteoblast activity, and mounting evidence suggests a role for the osteoimmune system in bone homeostasis. Bisphosphonate (BP) is an antiresorptive agent, but its treatment failure rate can be as high as 40%. Here, we performed single-cell RNA sequencing on peripheral immune cells from carefully selected postmenopausal women: non-osteoporotic, osteoporosis improved after BP treatment, and BP-failed cases. We found an increase in myeloid cells in patients with osteoporosis (specifically, T cell receptor+ macrophages). Furthermore, lymphoid lineage cells varied significantly, notably elevated natural killer cells (NKs) in the BP-failed group. Moreover, we provide fruitful lists of biomarkers within the immune cells that exhibit condition-dependent differences. The existence of osteoporotic- and BP-failure-specific cellular information flows was revealed by cell-cell interaction analysis. These findings deepen our insight of the osteoporosis pathology enhancing comprehension of the role of immune heterogeneity in postmenopausal osteoporosis and BP treatment failure., Competing Interests: Competing interests statement:The authors declare no competing interest.

As a daily physiological mechanism in bone, microdamage accumulation dissipates energy and helps to prevent fractures. However, excessive damage accumulation might bring adverse effects to bone mechanical properties, which is especially problematic among the osteoporotic and osteopenic patients treated by bisphosphonates. Some pre-clinical studies in the literature applied forelimb loading models to produce well-controlled microdamage in cortical bone. Ovariectomized animals were also extensively studied to assimilate human conditions of estrogen-related bone loss. In the present study, we combined both experimental models to investigate microdamage accumulation in the context of osteopenia and zoledronate treatment. Three-month-old normal and ovariectomized rats treated by saline or zoledronate underwent controlled compressive loading on their right forelimb to create in vivo microdamage, which was then quantified by barium sulfate contrast-enhanced micro-CT imaging. Weekly in vivo micro-CT scans were taken to evaluate bone (re)modeling and to capture microstructural changes over time. After sacrifice, three-point-bending tests were performed to assess bone mechanical properties. Results show that the zoledronate treatment can reduce cortical microdamage accumulation in ovariectomized rats, which might be explained by the enhancement of several bone structural properties such as ultimate force, yield force, cortical bone area and volume. The rats showed increased bone formation volume and surface after the generation of microdamage, especially for the normal and the ovariectomized groups. Woven bone formation was also observed in loaded ulnae, which was most significant in ovariectomized rats. Although all the rats showed strong correlations between periosteal bone formation and microdamage accumulation, the correlation levels were lower for the zoledronate-treated groups, potentially because of their lower levels of microdamage. The present study provides insights to further investigations of pharmaceutical treatments for osteoporosis and osteopenia. The same experimental concept can be applied in future studies on microdamage and drug testing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Early-stage breast cancer is usually treated with breast-conserving surgery followed by adjuvant radiation therapy. Acute skin toxicity is a common radiation-induced side effect experienced by many patients. Recently, a combination of bisphosphonates (zoledronic acid) and statins (pravastatin), or ZOPRA, was shown to radio-protect normal tissues by enhancing DNA double-strand breaks (DSB) repair mechanism. However, there are no studies assessing the effect of ZOPRA on cancerous cells. The purpose of this study is to characterize the in vitro effect of the zoledronic acid (ZO), pravastatin (PRA), and ZOPRA treatment on the molecular and cellular radiosensitivity of breast cancer cell lines., Materials: Two breast cancer cell lines, MDA MB 231 and MCF-7, were tested. Cells were treated with different concentrations of pravastatin (PRA), zoledronate (ZO), as well as their ZOPRA combination, before irradiation. Anti-γH2AX and anti-pATM immunofluorescence were performed to study DNA DSB repair kinetics. MTT assay was performed to assess cell proliferation and viability, and flow cytometry was performed to analyze the effect of the drugs on the cell cycle distribution. The clonogenic assay was used to assess cell survival., Results: ZO, PRA, and ZOPRA treatments were shown to increase the residual number of γH2AX foci for both cell lines. ZOPRA treatment was also shown to reduce the activity of the ATM kinase in MCF-7. ZOPRA induced a significant decrease in cell survival for both cell lines., Conclusions: Our findings show that pretreatment with ZOPRA can decrease the radioresistance of breast cancer cells at the molecular and cellular levels. The fact that ZOPRA was previously shown to radioprotect normal tissues, makes it a good candidate to become a therapeutic window-widening drug., (© 2023. The Author(s) under exclusive licence to Maj Institute of Pharmacology Polish Academy of Sciences.)

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, often presenting comorbidities like osteoporosis and requiring, in a relevant proportion of cases, treatment with bisphosphonates (BPs). This class of drugs was shown in preclinical investigations to also possess anticancer properties. We started an in vitro study of the effects of BPs on CLL B cells activated by microenvironment-mimicking stimuli and observed that, depending on drug concentration, hormetic effects were induced on the leukemic cells. Higher doses induced cytotoxicity whereas at lower concentrations, more likely occurring in vivo, the drugs generated a protective effect from spontaneous and chemotherapy-induced apoptosis, and augmented CLL B cell activation/proliferation. This CLL-activation effect promoted by the BPs was associated with markers of poor CLL prognosis and required the presence of bystander stromal cells. Functional experiments suggested that this phenomenon involves the release of soluble factors and is increased by cellular contact between stroma and CLL B cells. Since CLL patients often present comorbidities such as osteoporosis and considering the diverse outcomes in both CLL disease progression and CLL response to treatment among patients, illustrating this phenomenon holds potential significance in driving additional investigations., (© 2024. The Author(s).)

Objective: To evaluate the osseointegration of implants with hydrophobic (HFB) and hydrophilic (HFL) surfaces in a murine model of high-dose bisphosphonates (BPs)., Materials and Methods: Sixty-four rats were randomly allocated into four groups: control group with HFB implants (CG-HFB), control group with HFL implants (CG-HFL), BP group with HFB implants (BP-HFB), and BP group with HFL implants (BP-HFL). Animals were euthanized after 15 and 45 days (n=8). The dependent variables assessed were the removal torque (biomechanical analysis), the bone volume around the implants (%BV/TV) (microtomographic analysis), the bone-implant contact (%BIC), the bone between the threads (%BBT) (histomorphometric analysis), and the expression of bone metabolism markers (immunohistochemistry analysis)., Results: The CG-HFL and BP-HFL groups presented higher removal torque than the CG-HFB and BP-HFB implants. The %BIC of the CG-HFL surfaces was slightly higher than that of the CG-HFB implants. The BP-HFB and BP-HFL groups presented a higher %BIC than that of the CG-HFB and CG-HFL groups (p<0.001). BP therapy also increased the %BBT at both implant surfaces. Higher levels of ALP were observed in the matrix region of bone tissue on the HFL surfaces than on the HFB surfaces., Conclusion: Both surfaces enable osseointegration in rats under BP therapy., Clinical Relevance: The study demonstrates that hydrophobic (HFB) and hydrophilic (HFL) implant surfaces can promote osseointegration in rats undergoing bisphosphonate therapy. The HFL surfaces exhibited improved biomechanical performance, higher bone-implant contact, and increased bone volume, suggesting their potential clinical relevance for implant success in individuals on bisphosphonate treatment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The Aim of the Study: Was to investigate the dynamics of mandibular density in cancer patients during therapy with zolendronic acid., Materials and Methods: The study comprised 14 patients who received zolendronic acid at a dosage of 4 mg once every 28 days for bone metastases. In all 14 patients, measurements of mandibular density values on CT scans were performed over time., Results: Using multiple linear regression analysis, a model was developed to predict the effect of the number of zolendronic acid injections «X 1 » on the dynamics of mandibular density «Y». The resulting formula for predicting mandibular density is Y = 5.9 X 1 + 49 HU., Conclusion: The model has limitations due to the study design but still can be used by oncologists and dentists to assess mandibular density in patients taking zolendronic acid.

Objective: Irrigating solutions play an important role in the debridement and disinfection of the root canal space, and thus, it is crucial to comprehend their effects on the composition and surface structure of radicular dentine. This study evaluated and compared the effects of 17% ethylenediaminetetraacetic acid (EDTA), 9% 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) and 0.2% chitosan on the mineral content and erosion of radicular dentine when used as a final rinse., Methods: Sixty extracted human mandibular premolar teeth were decoronated and instrumented to ProTaper size F2. After final instrumentation, the samples were randomly divided into 4 groups (n=15) according to the type of final irrigant used: Normal saline (control), 17% EDTA, 9% HEBP and 0.2% chitosan. Field emission scanning electron microscopy was used to assess the erosion of radicular dentine, and energy dispersive X- ray spectroscopy was used to quantify the radicular dentine mineral composition at the coronal, middle and apical levels of all the prepared samples after final irrigation. The one-way analysis of variance was used for intra-group and inter-group comparisons of means, the Kruskal Wallis test for intra-group and inter-group comparisons of medians and Tukey's post hoc test for pairwise comparisons., Results: There was no significant difference in the levels of calcium (Ca), phosphorus (P) and Ca/P ratio after final rinse with 17% EDTA, 9% HEBP and 0.2% chitosan at all three root levels (p>0.05); except at the coronal level, where 0.2% chitosan caused significantly less alteration in Ca levels and Ca/P ratio than 17% EDTA and 9% HEBP respectively (p<0.05). 17% EDTA, 9% HEBP and 0.2% chitosan caused no erosion at the middle and apical levels. Meanwhile, 17% EDTA and 9% HEBP caused moderate erosion at the coronal level., Conclusion: Alternatives to 17% EDTA during final irrigation can be 9% HEBP and 0.2% chitosan. (EEJ-2023-06-078).

The Aim the Study: To analyze the density of the mandible in cancer patients during treatment with zoledronic acid., Materials and Methods: A retrospective cohort study included 45 patients with cancer aged 26-81 years (average age 55±12.88 years), of whom 14 patients had bone metastases ( n =14) and took 4 mg of zolendronic acid once every 28 days. The patients underwent standard PET-CT examinations in the «whole body» mode, and the density of the mandible was examined on CT. Radiation therapy was performed by intracavitary administration of strontium 89 chloride; remote radiation therapy with cisplatin radiomodification. In the presence of bone metastases, patients received complex supportive therapy with zolendronic acid. The effect of zolendronic acid on the density of the mandible in the frontal and lateral sections was studied by multidimensional dispersion analysis., Results: Statistically significant differences ( p =0.002) were revealed for density indicators according to CT scans of the mandible in the frontal region against the background of zolendronic acid therapy. We attribute the absence of statistically significant differences for the density of the mandible in the lateral sections ( p =0.101 and p =0.082) against the background of zolendronic acid therapy to a measurement bias. We attribute the absence of statistically significant differences in density indices against the background of hormonal, radiation, targeted and chemotherapy to the design of the study., Conclusion: Density measurement based on CT examination data can be recommended for use as an additional tool in assessing the effect of zolendronic acid on the density of the mandible. However, the method of measuring the density of the mandible in the lateral sections requires improvement to prevent measurement bias.

The aim of this study was to analyze the effect of ozone (OZN) therapy on the dynamics of bone tissue in ovariectomized rats treated with zoledronic acid (ZOL). Female Wistar rats aged 6 months ( n  = 110) were subjected to bilateral ovariectomy (OVX). At month 3 post-OVX, 10 animals were euthanized to characterize the bone tissue architecture using microtomography (micro-CT). The remaining animals were divided into two groups: ZOL group, administered with ZOL (100 μg/kg body weight); saline (SAL) group (0.45 mL of SAL solution), both for 28 days. At month 3 post-treatment, 10 animals from each group were euthanized to characterize the bone architecture using micro-CT. The remaining animals were divided into the following groups: ZOL ( n  = 20), ZOL + OZN ( n  = 20); SAL ( n  = 20), and SAL + OZN ( n  = 20). The animals in ZOL + OZN and SAL + OZN groups were intraperitoneally administered with OZN (0.7 mg/kg body weight) once every 2 days. On days 30 and 60, six animals from each group were euthanized for analysis and structural characterization of bones in the femoral head and spine. Some samples of the femoral neck were subjected to biomechanical tests, while some samples were analyzed under a laser confocal microscope. The other samples collected from the femoral neck and spine were analyzed for area of neoformed bone and used for performing inflammatory cell and osteocyte counts. Data were submitted to statistical analysis considering a significance level of p  < 0.05. Bone volume percentage and osteocyte and inflammatory cell counts were upregulated in the femoral head region of the ZOL + OZN group. Biomechanical analysis of the femoral neck revealed that the modulus of elasticity was similar between the ZOL and ZOL + OZN groups but differed significantly between the SAL and SAL + OZN groups. The positive areas for calcein and alizarin in the ZOL and ZOL + OZN groups were higher than those in the SAL and SAL + OZN groups. This suggested a positive synergistic effect of OZN and ZOL on the maintenance of bone mass and restoration of bone tissue vitality in ovariectomized rats.

Background: It is estimated that 1 in 3 women and 1 in 5 men over the age of 50 worldwide will experience an osteoporosis fracture during their lives. Neridronate is a third-generation bisphosphonate with established efficacy in metabolic bone disease. It can be used in the treatment of osteoporosis., Objectives: We aimed to conduct a meta-analysis of the effect of neridronate on the treatment of osteoporosis., Material and Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were used to guide the present study. We searched PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) for reports published until August 31, 2021, related to neridronate and osteoporosis. The modification of the bone mineral density (BMD, g/cm2) of the patient is the core indicator for neridronate treatment., Results: Significant increases in the BMD of the lumbar spine (mean difference (MD) = 5.99, 95% confidence interval (95% CI): 3.96-8.02), femoral neck (MD = 4.51, 95% CI: 2.01-7.01) and total hip (MD = 2.55, 95% CI: 2.10-3.00) were found. Greater improvement in the BMD of the lumbar spine and femoral neck could also be detected in patients with postmenopausal osteoporosis than with other causes of osteoporosis. Moreover, significant decreases in serum C-telopeptide of collagen type I (sCTX, standardized mean difference (SMD) = -0.84, 95% CI: -1.32--0.37) and bone alkaline phosphatase (ALP, MD = -5.29, 95% CI: -7.31--3.26) levels were observed., Conclusion: The pool analysis of the selected clinical trials indicates the great benefit of neridronate in improving the condition of patients with osteoporosis of all causes, particularly patients with postmenopausal osteoporosis, which causes an increase in BMD as well as in sCTX and bone ALP levels.

Bisphosphonate (BP)-based treatments have been extensively prescribed for bone-related conditions, particularly for osteoporosis. Their low bioavailability creates the need for prescribed dosage increase to reach therapeutic levels but generates a plethora of undesirable side effects. A viable approach to alleviating these issues is to design and exploit controlled release strategies. Herein, the controlled release profiles of 15 structurally characterized BPs (actual drugs and structural analogs) were thoroughly studied from tablets containing three (cellulose, lactose, and silica) or two (cellulose, and silica) excipients in human stomach-simulated pH conditions. The BPs were of two types, alkyl-BPs and amino-BPs. Alkyl-BPs included four derivatives of etidronate (acid, disodium, tetra-sodium, and monopotassium forms), medronic acid, and three analogs of etidronate, in which the -CH 3 group was replaced by the moieties -H, -CH 2 CH 2 CH 3 , and -CH 2 CH 2 CH 2 CH 2 CH 3 . Amino-BPs included the commercial drugs pamidronate, alendronate, neridronate, and ibandronate, as well as three analog compounds. Release curves were constructed based on data taken from 1 H NMR peak integration and were expressed as "% BP release" vs time. The controlled release profiles (initial release rate, plateau value, etc.) were correlated with certain structural features (number of hydrogen and metal-oxygen bonds), showing that the molecular and crystal lattice features of each BP profoundly influence its release characteristics. It was concluded that for all BPs, in general, the initial rate became lower as the total number of lattice interactions increased. For the alkyl-BPs elongation of the alkyl side chain seems to decelerate the release. Amino-BPs, in general, show slower release than the alkyl-BPs. No adverse effects of alkyl- and amino-BP drugs on NIH3T3 cell viability were noted.

Novel C6-substituted pyrazolo[3,4- d ]pyrimidine- and C2-substituted purine-based bisphosphonate (C6-PyraP-BP and C2-Pur-BP, respectively) inhibitors of the human geranylgeranyl pyrophosphate synthase (hGGPPS) were designed and evaluated for their ability to block the proliferation of multiple myeloma (MM), pancreatic ductal adenocarcinoma (PDAC), and colorectal cancer (CRC) cells. Pyrazolo[3,4- d ]pyrimidine analogs were identified that induce selective intracellular target engagement leading to apoptosis and downregulate the prenylation of Rap-1A in MM, PDAC, and CRC cells. The C6-PyraP-BP inhibitor RB-07-16 was found to exhibit antitumor efficacy in xenograft mouse models of MM and PDAC, significantly reducing tumor growth without substantially increasing liver enzymes or causing significant histopathologic damage, usually associated with hepatotoxicity. RB-07-16 is a metabolically stable compound in cross-species liver microsomes, does not inhibit key CYP 450 enzymes, and exhibits good systemic circulation in rat. Collectively, the current studies provide encouraging support for further optimization of the pyrazolo[3,4- d ]pyrimidine-based GGPPS inhibitors as potential human therapeutics for various cancers.

The development of magnesium-derived biomaterials is one of the most promising research in bone tissue engineering, and related strategies have been extensively used for tendon, skull, cartilage, and bone regeneration. Also, alendronate, a well-recognized drug for osteoporosis treatment, has recently attracted a great deal of attention for bone repair. However, rapid corrosion in vivo of Mg 2+ and low systemic bioavailability of alendronate are the main limitations hampering their full exploitation. In this work, by means of physical and chemical cross-linking conjugating magnesium-metal-organic frameworks (Mg-MOFs) and bone-targeting alendronate to biocompatible gelatin scaffolds, a facile method is developed for the preparation of organic/inorganic nanocomposite gel scaffolds. The results affirmed that the nanocomposite gel scaffolds possessed excellent biocompatibility, continuous slow release of Mg 2+ and alendronate, strong bone affinity, and bone regeneration. It is noteworthy that the continuous slow release of Mg 2+ and alendronate could induce the macrophage switch to the M2 phenotype and promote osteogenic differentiation in the early stage, resulting in improved bone regeneration during implanting the scaffolds into the distal femoral. In summary, Mg-MOFs-loaded alendronate-modified gelatin gel scaffolds have been developed, exhibiting great potential for bone regenerative.

BACKGROUND: Bone mineral density (BMD) is a measure of skeletal health that may foretell disorders like osteoporosis. METHODS: To reduce bone losses on Earth, treatments include exercise, diet, and drugs. Each impact osteoblast and osteoclast activity dictates skeletal remodeling and subsequent BMD changes. BMD loss is a concern during spaceflight. For astronauts, low BMD undermines in-flight tasks and compromises their postflight health. RESULTS: While bisphosphonates exhibited promise as an in-flight bone loss treatment, study results are mixed, and this class of drugs has numerous side-effects. While the role antiresorptive agents play in reducing BMD loss is discussed, this review focuses on exercise-induced strains and nutrition, two in-flight treatments without bisphosphonates' side-effects. DISCUSSION: Evidence supports in-flight exercise and a healthy diet with vitamin D and Ca +2 supplementation to limit BMD loss. This review suggests how exercise and nutrition may limit BMD loss during spaceflight. Also discussed is an in-flight version of the inertial exercise trainer (IET; Impulse Technologies, Knoxville TN). By imparting high bone-strain magnitudes, rates, and frequencies with less mass, footprint, and power needs than other forms of in-flight resistance exercise hardware, the IET warrants inquiry for use aboard future long-term spaceflights. Caruso J, Patel N, Wellwood J, Bollinger L. Impact of exercise-induced strains and nutrition on bone mineral density in spaceflight and on the ground . Aerosp Med Hum Perform. 2023; 94(12):923-933.

Background: Age-related muscle decline (sarcopenia) associates with numerous health risk factors and poor quality of life. Drugs that counter sarcopenia without harmful side effects are lacking, and repurposing existing pharmaceuticals could expedite realistic clinical options. Recent studies suggest bisphosphonates promote muscle health; however, the efficacy of bisphosphonates as an anti-sarcopenic therapy is currently unclear., Methods: Using Caenorhabditis elegans as a sarcopenia model, we treated animals with 100 nM, 1, 10, 100 and 500 μM zoledronic acid (ZA) and assessed lifespan and healthspan (movement rates) using a microfluidic chip device. The effects of ZA on sarcopenia were examined using GFP-tagged myofibres or mitochondria at days 0, 4 and 6 post-adulthood. Mechanisms of ZA-mediated healthspan extension were determined using combined ZA and targeted RNAi gene knockdown across the life-course., Results: We found 100 nM and 1 μM ZA increased lifespan (P < 0.001) and healthspan [954 ± 53 (100 nM) and 963 ± 48 (1 μM) vs. 834 ± 59% (untreated) population activity AUC, P < 0.05]. 10 μM ZA shortened lifespan (P < 0.0001) but not healthspan (758.9 ± 37 vs. 834 ± 59, P > 0.05), whereas 100 and 500 μM ZA were larval lethal. ZA (1 μM) significantly improved myofibrillar structure on days 4 and 6 post-adulthood (83 and 71% well-organized myofibres, respectively, vs. 56 and 34% controls, P < 0.0001) and increased well-networked mitochondria at day 6 (47 vs. 16% in controls, P < 0.01). Genes required for ZA-mediated healthspan extension included fdps-1/FDPS-1 (278 ± 9 vs. 894 ± 17% population activity AUC in knockdown + 1 μM ZA vs. untreated controls, respectively, P < 0.0001), daf-16/FOXO (680 ± 16 vs. 894 ± 17%, P < 0.01) and agxt-2/BAIBA (531 ± 23 vs. 552 ± 8%, P > 0.05). Life/healthspan was extended through knockdown of igdb-1/FNDC5 (635 ± 10 vs. 523 ± 10% population activity AUC in gene knockdown vs. untreated controls, P < 0.01) and sir-2.3/SIRT-4 (586 ± 10 vs. 523 ± 10%, P < 0.05), with no synergistic improvements in ZA co-treatment vs. knockdown alone [651 ± 12 vs. 635 ± 10% (igdb-1/FNDC5) and 583 ± 9 vs. 586 ± 10% (sir-2.3/SIRT-4), both P > 0.05]. Conversely, let-756/FGF21 and sir-2.2/SIRT-4 were dispensable for ZA-induced healthspan [630 ± 6 vs. 523 ± 10% population activity AUC in knockdown + 1 μM ZA vs. untreated controls, P < 0.01 (let-756/FGF21) and 568 ± 9 vs. 523 ± 10%, P < 0.05 (sir-2.2/SIRT-4)]., Conclusions: Despite lacking an endoskeleton, ZA delays Caenorhabditis elegans sarcopenia, which translates to improved neuromuscular function across the life course. Bisphosphonates might, therefore, be an immediately exploitable anti-sarcopenia therapy., (© 2023 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.)

Alendronate (ALN) is a second-generation bisphosphonate widely used for osteoporosis and cancer-induced bone lesions. Many studies have confirmed a strong relationship between osteonecrosis of the jaws (ONJ) development and oral bisphosphonates, especially ALN, although the molecular mechanisms underlying this pathology have not yet been elucidated. The reduction in bone turnover and vascularization usually observed in ONJ are the result of ALN action on different cell types harboured in oral microenvironment, such as osteoclasts, endothelial cells, and periodontal ligament stem cells (PDLSCs). In this perspective, the present study aims to investigate the effects of different ALN concentrations (2 μM, 5 μM, 10 μM, 25 μM, 50 μM) on the phenotype and functional properties of human PDLSCs (hPDLSCs). hPDLSCs showed a decrease in cell viability (MTT assay) only when treated with ALN concentration of 10 μM or larger for 48 h and 72 h. Cell cycle analysis revealed a moderate increase in proportion of S-phase cells after exposure to low ALN concentration (2-5 μM), an effect that was reverted after exposure to 10-50 μM ALN. Conversely, cell death was evidenced via Annexin V/PI assay at very high concentration of ALN (50 μM) after 4 days of treatment. In addition, we explored whether the effects of ALN on hPDLSCs growth and survival can be mediated by its ability to modulate oxidative stress. To this, we quantified the intracellular ROS amount and lipid peroxidation by using DCF probe and Bodipy staining, respectively. Flow cytometry analysis showed that ALN induced a dose-dependent reduction of intracellular oxidative stress and lipid peroxidation upon treatment with low concentrations at both 48 h and 72 h. Increased levels of oxidative stress was reported at 50 μM ALN and was also confirmed via TEM analysis. Despite the stability of the cellular immunophenotype, hPDLSCs showed impaired mobility after ALN exposure. Chronic exposure (7-14 days) to ALN in the range of 2-10 μM significantly decreased the expression of the differentiation-related factors ALP, RUNX2, COLI, and OPN as well as the osteogenic ability of hPDLSCs compared with untreated cells. Conversely, higher doses were found to be neutral. Our findings indicated that the effects of ALN on hPDLSCs behavior are dose-dependent and suggest a role for oxidative stress in ALN-induced cell death that may lead to novel therapeutic approaches for ONJ., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Recent studies have shown that bisphosphonates can also impact osteoblasts besides osteoclasts. This study aimed to evaluate the effects of different concentrations of Zoledronic acid (ZA) during the osteogenic differentiation of human Bone Marrow Stem Cells (hBMSCs) in vitro. Thus, osteogenic differentiation of hBMSCs was conducted with different concentrations of Zoledronic Acid (ZA) (0, 0.1, 1.0, and 5.0 μM) for the first 3 days. Cell metabolism was quantified at 1-, 3-, 7-, and 14 days. At 7- and 14-days, the following analyses were performed: 1) mineralization nodule assay, 2) LIVE/DEAD™, 3) cell adhesion and spreading, 4) alkaline phosphatase (ALP) activity, and 5) qPCR analysis for RUNX-2), ALPL, and COL1 A1. Data were analyzed by ANOVA 2-way, followed by Tukey's post hoc test (p < 0.05). Cell metabolism (3-, 7-, and 14-days) (p < 0.001), mineralization (7-, 14-days) (p < 0.001), and ALP activity (14-days) (p < 0.001) were reduced in ZA 5.0 µM when compared to control (no ZA). Also, ZA 5.0 µM downregulated the expression of RUNX2 at 7- and 14-days (p < 0.001). It is possible to conclude that ZA (5.0 µM) can impair hBMSC differentiation into osteoblasts and interferes with its mineralization phase., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Osteoporosis is a metabolic bone disorder typified by a reduction in bone mass and structural degradation of bone tissue, leading to heightened fragility and vulnerability to fractures. The incidence of osteoporosis increases with age, making it a significant public health challenge. The pathogenesis of osteoporosis involves an imbalance between osteoblast-mediated bone formation and resorption. The current treatment options for osteoporosis include bisphosphonates, hormone replacement therapy (HRT), selective estrogen receptor modulators (SERMs), and denosumab. The recent advances in small-molecule drugs for the clinical treatment of osteoporosis offer promising options for improving bone health and reducing fracture risk. This review aims to provide an overview of the clinical applications and synthetic routes of representative small-molecule drugs for the treatment of osteoporosis. A comprehensive understanding of the synthetic methods of drug molecules for osteoporosis may inspire the development of new, more effective, and practical synthetic techniques for treating this condition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Background: Tumour associated macrophages (TAMs) are important players in breast tumour progression and metastasis. Clinical and preclinical evidence suggests a role for zoledronate (ZOL) in breast cancer metastasis prevention. Further, zoledronate is able to induce inflammatory activation of monocytes and macrophages, which can be favourable in cancer treatments. The inherent bone tropism of zoledronate limits its availability in soft tissues and tumours. In this study we utilised an orthotopic murine breast cancer model to evaluate the possibility to use liposomes (EMP-LIP) to target zoledronate to tumours to modify TAM activation., Methods: Triple-negative breast cancer 4T1 cells were inoculated in the 4th mammary fat pad of female Balb/c mice. Animals were divided according to the treatment: vehicle, ZOL, EMP-LIP and liposome encapsulated zoledronate (ZOL-LIP). Treatment was done intravenously (with tumour resection) and intraperitoneally (without tumour resection). Tumour growth was followed by bioluminescence in vivo imaging (IVIS) and calliper measurements. Tumour-infiltrating macrophages were assessed by immunohistochemical and immunofluorescence staining. Protein and RNA expression levels of inflammatory transcription factors and cytokines were measured by Western Blotting and Taqman RT-qPCR., Results: Liposome encapsulated zoledronate (ZOL-LIP) treatment suppressed migration of 4T1 cell in vitro. Tumour growth and expression of the angiogenic marker CD34 were reduced upon both ZOL and ZOL-LIP treatment in vivo. Long-term ZOL-LIP treatment resulted in shift towards M1-type macrophage polarization, increased CD4 T cell infiltration and activation of NF-κB indicating changes in intratumoural inflammation, whereas ZOL treatment showed similar but non-significant trends. Moreover, ZOL-LIP had a lower bisphosphonate accumulation in bone compared to free ZOL., Conclusion: Results show that the decreased bisphosphonate accumulation in bone promotes the systemic anti-tumour effect of ZOL-LIP by increasing inflammatory response in TNBC tumours via M1-type macrophage activation., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2023. Published by Elsevier B.V.)

Osteosarcoma (OS) is a malignant tumor, fatal for pediatric patients who do not respond to chemotherapy, alternative therapies and drugs can provide better outcomes. Zoledronic acid (Zol) belonging to the class of bisphosphonates (BPs) has a direct antitumor ability to prevent Ras GTPases modification and stimulate apoptosis. Despite advances in maintaining balance in skeletal events and direct anticancer properties, Zol causes cytotoxicity to normal healthy pre-osteoblast cells, hampering mineralization and differentiation. The study reports the preparation and evaluation of a nanoformulation that can diminish the existing drawbacks of native Zol. The cytotoxic effect is evaluated on bone cancer cells and healthy bone cells with three different cell lines namely, K7M2 (mouse OS cell line), SaOS2 (human OS cell line), and MC3T3E1 (healthy cell counterpart). It is observed that Zol nanoformulation is uptaken more (95%) in K7M2 whereas in MC3T3E1, the percent population internalizing nanoparticles (NPs) is 45%. Zol has a sustained release of 15% after 96 h from the NP which leads to a rescuing effect on the normal pre-osteoblast cells. In conclusion, it can be stated that Zol nanoformulation can be used as a good platform for a sustained release system with minimum side effects to normal bone cells., (© 2023 Wiley-VCH GmbH.)

Introduction: The increasing prevalence of osteoporosis and chronic kidney disease (CKD) due to the aging of society has highlighted the need for development of effective treatments for elderly patients. This study examined whether the combination of treadmill exercise therapy and alendronate (ALN) can improve bone mineral density (BMD) and bone strength without worsening renal function in adenine-induced CKD model rats., Materials and Methods: 8-week-old male Wistar rats (n = 70) were divided into experimental groups based on the treatment protocol, i.e., non-CKD (control), vehicle only (CKD), ALN only, exercise only, and combined ALN plus exercise. A 0.75% adenine diet was used to induce CKD. Groups were killed at either 20 or 30 weeks of age. Comprehensive assessments included serum and urine biochemistry tests, renal histology, bone histomorphometry, BMD measurement, micro-computed tomography examinations, and biomechanical testing., Results: Blood biochemistry tests, urine analyses and histological evaluations of the kidney demonstrated that ALN treatment did not worsen renal function or kidney fibrosis in moderate-stage CKD model rats. Both ALN and treadmill exercise significantly suppressed bone resorption (p < 0.05-p < 0.01). Moreover, ALN monotherapy and combined ALN and treadmill exercise significantly improved BMD of the lumbar spine and femur, bone microstructure, and trabecular bone strength (p < 0.05-p < 0.01). Treadmill exercise was also shown to decrease cortical porosity at the mid-diaphysis of the femur and improve kidney fibrosis., Conclusion: The combination of ALN and treadmill exercise is effective in improving BMD, the microstructure of trabecular and cortical bone, and bone strength, without compromising renal function in adenine-induced CKD model rats., (© 2023. The Japanese Society Bone and Mineral Research.)

Introduction: Bisphosphonates are antiresorptive drugs used worldwide to treat systemic bone pathologies. This study aimed to assess the impact of zoledronic acid on the progression of induced apical periodontitis and the expression of cytokines interleukin (IL)-1β, IL-10, IL-6, and tumor necrosis factor alpha (TNF-α) in a mouse model., Methods: Sixteen female isogenic BALB/c mice 6 weeks of age were distributed into 2 groups: mice with induced apical periodontitis (the AP group, n = 8) and mice with induced apical periodontitis treated with zoledronic acid (the AP-ZA group, n = 8). The AP-ZA group received a dose of 125 μg/kg zoledronic acid diluted in sterile saline solution administered intraperitoneally once a week for 4 weeks before pulp exposure, whereas the AP group received only saline solution. Pulp exposures were performed on the maxillary first molars for the induction of apical periodontitis, and mice were euthanized after 7 and 21 days. The jaws were collected; scanned using micro-computed tomographic imaging; and processed for polymerase chain reaction analysis of IL-1β, IL-10, IL-6, and TNF-α. The Student t test was performed for parametric data, and Mann-Whitney U tests were used for nonparametric data. The level of significance was set at 5%., Results: Micro-computed tomographic imaging revealed higher bone resorption in the AP group compared with the AP-ZA group at both time points (P < .05). Real-time polymerase chain reaction demonstrated higher TNF-α expression in the AP group at both time points and higher IL-6 and IL-1β expression in the AP group at the 7- and 21-day time points, respectively, compared with the AP-ZA group (P < .05). No differences were observed regarding IL-10 expression between the groups., Conclusions: Zoledronic acid had significant anti-inflammatory and antiresorptive effects on apical periodontitis in mice., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Fibrous dysplasia (FD) is characterized by expansile fibro-osseous lesions that may occur in association with endocrinopathies as part of McCune-Albright syndrome (MAS). Craniofacial FD is a significant source of morbidity and most commonly involves the gnathic bones. There is a critical need to understand the natural history and risk factors for gnathic FD progression to develop preventative trials and identify candidates for intervention. The purpose of this study was to characterize gnathic FD lesion expansion and to identify risk factors associated with lesion growth. Patients with gnathic FD and serial CT imaging were evaluated. Volumetric analyses of CT scans were performed using MIM Encore software. Generalized mixed model analysis was used to account for intra-subject correlation, with FD lesion volume as the dependent variable. In addition to age, effects of MAS-associated endocrinopathies, sex, disease severity, and bisphosphonate treatment were evaluated. A total of 104 total lesions in 52 patients were characterized longitudinally. Median age at initial scan was 8.8 years (range 3.4-18.8), and median age at final scan was 16.8 years (range 6.9-33.4 years). The median number of scans per subject was 4 (range 2-14). FD lesion volume increased with age (2.50 cm 3 /yr, 95% confidence interval [CI] 1.95-3.04, p < 0.001). However, lesion expansion rate decreased over time (-0.05 cm 3 /yr, 95% CI -0.07 to 0.04, p < 0.001). Mandibular lesions tended to expand at a greater rate than maxillary lesions (p < 0.001). Growth hormone excess was associated with accelerated expansion rate (p = 0.002). Other MAS-associated endocrinopathies, pubertal status, sex, weight, lesion density, disease severity, and bisphosphonate treatment were not associated with lesion volume or expansion. Gnathic FD lesion expansion is most rapid in younger children and declines as patients approach adulthood. The availability of quantitative natural history data will guide clinicians in identifying patients who are candidates for medical and surgical interventions and clinical trials for preventative therapies. Published 2023. This article is a U.S. Government work and is in the public domain in the USA., (Published 2023. This article is a U.S. Government work and is in the public domain in the USA.)