Pharmacology of bisphosphonates

Impact of antiresorptive agents on mortality risk in postmenopausal women with osteoporosis: insights from a nationwide cohort study

IMPORTANCE

Osteoporosis-related fractures are associated with increased mortality risk among postmenopausal women, yet the impact of antiosteoporotic medications on mortality is not fully understood.

OBJECTIVE

This study evaluates the effect of antiresorptive agents (ARs) on mortality risk in postmenopausal women with osteoporosis.

DESIGN

This is a nationwide cohort study using data from the National Screening Program for Transitional Ages (2008-2017).

SETTING

Data were derived from a national cohort of postmenopausal women in South Korea.

PARTICIPANTS

This study included 117 871 postmenopausal women diagnosed with osteoporosis. Of them, 15 895 patients who used ARs, such as bisphosphonates or selective estrogen receptor modulators, for at least 1 year were matched 1:1 with nonusers using propensity scores.

EXPOSURES

Exposure to ARs for at least 1 year was compared with no AR use.

MAIN OUTCOMES AND MEASURE

Mortality outcomes were assessed using multivariable Cox proportional hazard regression models, focusing on all-cause mortality and cause-specific mortality, particularly cardiovascular disease (CVD) and injury-/fracture-related deaths.

RESULTS

In AR users, there were 102 deaths (mortality rate 1.41 per 1000 person-years), compared with 221 deaths in non-users (mortality rate 3.14 per 1000 person-years), yielding a hazard ratio (HR) of 0.43 (95% CI, 0.34-0.54). Antiresorptive agent users showed a 52% reduction in CVD mortality risk (HR, 0.48; 95% CI, 0.34-0.69) and a 54% reduction in injury-/fracture-related mortality risk (HR, 0.46; 95% CI, 0.27-0.76). The analysis indicated a consistent decrease in all-cause and CVD mortality risks with longer durations of AR use.

CONCLUSIONS AND RELEVANCE

The use of ARs in postmenopausal women with osteoporosis is associated with significantly lower risks of all-cause mortality, especially from cardiovascular events and fractures. The mortality reduction benefits appear to be enhanced with prolonged AR therapy, highlighting the potential importance of sustained treatment in this population.

Bisphosphonate-Related Osteonecrosis of the Jaw and Oral Microbiome: Clinical Risk Factors, Pathophysiology and Treatment Options

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) represents a serious health condition, impacting the lives of many patients worldwide. The condition challenges clinical care due to its complex etiology and limited therapeutic options. A thorough understanding of the pathophysiological and patient-related factors that promote disease development is essential. Recently, the oral microbiome has been implicated as a potential driver and modulating factor of BRONJ by several studies. Modern genomic sequencing methods have provided a wealth of data on the microbial composition of BRONJ lesions; however, the role of individual species in the process of disease development remains elusive. A comprehensive PubMed search was conducted to identify relevant studies on the microbiome of BRONJ patients using the terms "microbiome", "osteonecrosis of the jaws", and "bisphosphonates". Studies focusing on symptoms, epidemiology, pathophysiology, risk factors, and treatment options were included. The principal risk factors for BRONJ are tooth extraction, surgical procedures, and the administration of high doses of bisphosphonates. Importantly, the oral microbiome plays a significant role in the progression of the disease. Several studies have identified alterations of microbial composition in BRONJ lesions. However, there is no consensus regarding bacterial species that are associated with BRONJ across studies. The bacterial genera typically found include Actinomyces, Fusobacterium, and Streptococcus. It is postulated that these microbes contribute to the pathogenesis of BRONJ by promoting inflammation and disrupting normal bone remodeling processes. Current therapeutic approaches are disease-stage-specific and the necessity for more effective treatment strategies remains. This review examines the potential causes of and therapeutic approaches to BRONJ, highlighting the link between microbial colonization and BRONJ development. Future research should seek to more thoroughly investigate the interactions between bisphosphonates, the oral microbiome, and the immune system in order to develop targeted therapies.

Bisphosphonate-Induced Orbital Cellulitis in a Patient With Suspected Parathyroid Carcinoma: A Case Report

Bisphosphonates are widely used for a number of metabolic bone conditions. Orbital inflammation is a very rare side effect of bisphosphonate therapy that can risk permanent visual loss. We describe the complex case and successful treatment of a 79-year-old man who developed orbital cellulitis following the use of intravenous pamidronate disodium for severe hypercalcaemia. The challenges regarding the diagnosis of parathyroid carcinoma are also discussed.

Non-biological Antiresorptive: Bisphosphonates

Background

Bisphosphonates, synthetic analogs of endogenous pyrophosphates, are pivotal in managing various bone disorders, primarily osteoporosis, which affects millions globally. While osteoporosis, especially postmenopausal osteoporosis, significantly benefits from bisphosphonate therapy, considerations arise regarding their administration and potential side effects.

Clinical application of Bisphosphonates

Bisphosphonates, divided into nitrogen-containing and non-nitrogenous groups, exert their influence through distinct mechanisms, with the former being notably more potent. The role of bisphosphonates in other diseases, such as Paget's bone and skeletal metastasis disease is also discussed. Detailed information on the administration routes, dosage regimens, and considerations for drug holidays is provided. The article navigates through the chemical structure, generations, and mechanism of action of bisphosphonates. The article covers administration routes, dosage regimens, and drug holidays, in addition to discussing potential adverse effects and contraindications.

Conclusions

Bisphosphonates hold an unrivaled legacy in the management of osteoporosis. The ubiquitous availability and the cost-effectiveness of these time-tested medications make them an invaluable asset in the osteoporosis treatment landscape, especially in developing nations like India.

Zoledronic acid sequential to teriparatide may promote greater inhibition of bone resorption than zoledronic acid alone

Background

Teriparatide (TPTD) should be followed by an antiresorptive to maximize bone mineral density gain and anti-fracture protection. Infrequent zoledronic acid (ZOL) administration has demonstrated effectiveness. The duration of ZOL effect following TPTD is unknown.

Objective

To evaluate the effect of ZOL on bone resorption marker in a post-TPTD versus ZOL-alone scenario in osteoporotic patients.

Design

Retrospective cohort study.

Methods

Patients treated with TPTD followed by ZOL (TPTD-ZOL) or with a single ZOL infusion were identified in the database of a tertiary referral center. Clinical and laboratory data, including C-terminal telopeptide of type I collagen (CTX) following ZOL treatment, were compared.

Results

Twenty-six patients (93% women) treated with TPTD-ZOL and 41 with ZOL were comparable in age (median 70.1 versus 69.6 years, p = 0.6) and sex. Timing of CTX measurement post-ZOL was the same, median 1.0 year. CTX was lower following TPTD-ZOL (median 142.1 versus 184.2 pg/mL, p = 0.005). In a multivariable regression model (controlled for baseline characteristics), pretreatment with TPTD strongly predicted CTX <150 pg/mL, 1 year following ZOL (odds ratio = 7.5, 95% CI 1.3-58.1, p = 0.03). In a subgroup with sequential CTX measurements following one ZOL, significantly lower levels persisted in the TPTD-ZOL group for a median of 4.4 years follow-up.

Conclusion

ZOL-administered sequential to TPTD yielded deeper and more prolonged bone resorption suppression than ZOL alone. Prospective data are needed to confirm whether in a sequential treatment scenario, subsequent ZOL dosing interval should be less frequent.

Bisphosphonates and Atypical Femur Fractures: Is the Relationship Causal or Casual?

Bisphosphonates (BPs) are a time-tested drug class with multivariate use cases. They are used in pathologies ranging from osteoporosis to Paget's disease, and also help in accelerated fracture healing. They have been used to treat both benign and malignant lesions of the skeletal system since a long time. However, there have been reports of increased incidences of atypical femoral fractures (AFFs) in patients exhibiting chronic use of bisphosphonates in the past years. This has led to the widespread dissuasion of physicians and practitioners from using the drug class. By means of this review of the literature, the authors aim to investigate the relationship between BP use and its association with AFFs. The review focuses on and elucidates the basic pharmacology of BPs and goes on to illustrate the indications of BPs in various pathologies of the musculoskeletal system, further exploring the effects of BPs on the healing of various bony fractures. The authors also explore the incidences of other pathologies, such as osteonecrosis of the jaw and nephropathies associated with BP use, and elaborate on their features. Through this review, the authors have tried to educate and induce critical thinking on the part of clinicians and medical professionals in regard to prescribing BPs to patients that need them, by keeping in mind the risk-reward relationship that accompanies their use.

Awareness, perceptions and attitudes toward medication-related osteonecrosis of the jaw among physicians who treat osteoporosis

Osteoporosis is the most common indication for antiresorptive drugs (ARDs). Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication of ARDs. Multiple risk factors can increase the risk of MRONJ, one of which is the duration of ARD intake, which is usually prolonged for osteoporosis cases. Prevention of MRONJ relies on collaborative care between treating physicians and dental practitioners. Therefore, knowledge about MRONJ and its prevention strategies is crucial for both teams.

Aim

This study aimed to assess the knowledge and attitudes of physicians toward MRONJ in osteoporosis patients. Another aim was to develop recommendations for the prevention of MRONJ.

Materials and methods

Through an online survey, basic information such as the practice location, training, knowledge, perceptions, and attitudes of physicians regarding ARDs and MRONJ in osteoporosis patients was collected. Statistical analysis was performed for all variables, and their correlations were explored.

Results

A total of 221 physicians participated in the survey: 34.8% were rheumatologists, 25.3% were endocrinologists, 8.6% were family medicine physicians, 5.9% were orthopedists, and 5.9% were internal medicine physicians. Of them, 58.0% reported more than 6 years of experience. Only 78.7% were aware of MRONJ and recognized that bisphosphonates (BPs) can contribute to MRONJ. In contrast, 56.0% recognized denosumab as a causative factor for MRONJ. Duration of ARD therapy and pre- and post-ARD dental care were known to influence the risk of MRONJ by 62% and 65.6% of the participants, respectively. Only 41.6% and 31.2% of participants informed patients about MRONJ prior to BP and denosumab therapy, respectively. Only 25.3% and 20.8% referred patients to dentists before BP and denosumab therapy, respectively. Overall, 65.6% of the participants had a negative attitude toward MRONJ, and 34.4% had a positive attitude. A positive attitude was mostly observed among rheumatologists (55.8%) compared to other specialists (p <0.001). More years of experience were associated with a higher level of knowledge and positive attitude.

Conclusion

The findings of this study identified a notable gap in the awareness, knowledge and attitudes of physicians regarding MRONJ in osteoporosis patients. Continuing education programs about ARDs and MRONJ risk are highly recommended.

Medication-Related Osteonecrosis of the Jaws: A Comparison of SICMF-SIPMO and AAOMS Guidelines

(1) Background: Medication-related osteonecrosis of the jaws (MRONJ) is an adverse drug reaction characterized by progressive bone disruption and necrosis in the mandibular and/or maxillary bones. It occurs in individuals who have received antiresorptive drugs without prior radiotherapy. Since its first reported cases in the USA in 2003, extensive literature has emerged worldwide, leading to significant advancements in understanding MRONJ's pathogenesis and management. (2) Results: This article aims to compare the current national recommendations provided by the Italian Society of Maxillofacial Surgery (SICMF)/Italian Society of Oral Pathology and Medicine (SIPMO) and the American Association of Oral and Maxillofacial Surgeons (AAOMS). (3) Conclusions: Historically, the AAOMS advocated for a more conservative approach compared to the Italian guidelines. However, in their 2022 update, the AAOMS adopted a different perspective based on reported evidence, highlighting the advantages of early surgical treatment. Despite resolving some initial controversies, differences still exist between the two sets of recommendations, particularly regarding diagnosis and staging.

A colloidal hydrogel-based drug delivery system overcomes the limitation of combining bisphosphonates with bioactive glasses: in vitro evidence of a potential selective bone cancer treatment allied with bone regeneration

Bisphosphonates are a class of drugs that induce bone cancer cell death and favor bone regeneration, making them suitable for bone cancer treatment. However, when combined with bioactive glasses to enhance bone regeneration, a chemical bond between biphosphonates and the glass surface inactivates their mechanism of action. A new colloidal hydrogel-based drug delivery system could overcome that limitation once bisphosphonates, such as zoledronic acid (ZA), are incorporated into hydrogel micelles, avoiding their interaction with the glass surface. In this work, we proposed formulations based on a poloxamer 407 thermo-responsive hydrogel matrix containing holmium-doped bioactive glass nanoparticles and different concentrations (0.05 and 5 mg/mL) of ZA. We characterized the influence of the glass and the ZA on the hydrogel properties. In addition, a drug concentration screening was performed, and biological characterizations evaluated the best result. The biological characterization consisted of evaluating cytotoxicity and in vitro bone regeneration ability through cell migration and quantification of genes related to osteogeneses through RT-PCR. The results suggest that the addition of glasses and ZA to the poloxamer did not significantly influence the sol-gel transition of the hydrogels (around 13 °C) regardless of the ZA content. However, the ZA at high concentration (PL-ZA100) decreased the enthalpy of gel formation from 68 to 43 kJ.mol^-1 when compared with the pure hydrogel formulation (PL), suggesting a water structurer role of ZA, which is withdrawn when glass particles are added to the system (PL-BG5Ho-ZA100). Solid-state 31P nuclear resonance spectroscopy results showed that part of the ZA is chemically bonded to the glass surface, which explains the withdrawal in the water structurer role of ZA when the glasses were incorporated into the hydrogel. Besides, based on the drug release results, we proposed a model where part of the ZA is "free," encapsulated in the hydrogel matrix, while another part of the ZA is bonded to the glass surface. Finally, considering the in vitro results and our proposed model, the ratio between "free" and "bonded" ZA in our drug delivery systems showed in vitro evidence of a cancer treatment that selectively kills osteosarcoma cells while still favoring an osteogenic microenvironment. By overcoming the limitation of combining bisphosphonates with bioactive glasses, hydrogel-based drug delivery systems can be a solution for the development of new formulations proposed for bone cancer treatment in conjunction with bone regeneration.

Cardiovascular Calcification Heterogeneity in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) exhibit tremendously elevated risk for cardiovascular disease, particularly ischemic heart disease, due to premature vascular and cardiac aging and accelerated ectopic calcification. The presence of cardiovascular calcification associates with increased risk in patients with CKD. Disturbed mineral homeostasis and diverse comorbidities in these patients drive increased systemic cardiovascular calcification in different manifestations with diverse clinical consequences, like plaque instability, vessel stiffening, and aortic stenosis. This review outlines the heterogeneity in calcification patterning, including mineral type and location and potential implications on clinical outcomes. The advent of therapeutics currently in clinical trials may reduce CKD-associated morbidity. Development of therapeutics for cardiovascular calcification begins with the premise that less mineral is better. While restoring diseased tissues to a noncalcified homeostasis remains the ultimate goal, in some cases, calcific mineral may play a protective role, such as in atherosclerotic plaques. Therefore, developing treatments for ectopic calcification may require a nuanced approach that considers individual patient risk factors. Here, we discuss the most common cardiac and vascular calcification pathologies observed in CKD, how mineral in these tissues affects function, and the potential outcomes and considerations for therapeutic strategies that seek to disrupt the nucleation and growth of mineral. Finally, we discuss future patient-specific considerations for treating cardiac and vascular calcification in patients with CKD-a population in need of anticalcification therapies.

Clinical values of serum Semaphorin 4D (Sema4D) in medication‑related osteonecrosis of the jaw

BACKGROUND

Bisphosphonates (BPs) are widely used in clinical practice to prevent and treat bone metabolism-related diseases. Medication-related osteonecrosis of the jaw (MRONJ) is one of the major sequelae of BPs use. Early prediction and intervention of MRONJ are of great significance.

METHODS

Ninety-seven patients currently on treatment with BPs or with a history of BPs usage and 45 healthy volunteers undergoing dentoalveolar surgery were included in this study. Participants' serum Semaphorin 4D (Sema4D) levels were measured and analyzed before participants underwent surgery (T0) and after a 12-month follow-up (T1). Kruskal-Wallis test and ROC analysis were used to examine the predictive effect of Sema4D on MRONJ.

RESULTS

Sema4D levels in serum of patients corresponding to confirmed MRONJ were significantly lower at both T0 and T1 time points compared to non-MRONJ and healthy controls. Sema4D has a statistically predictive effect on the occurrence and diagnosis of MRONJ. Serum Sema4D levels were significantly reduced in MRONJ class 3 patients. MRONJ patients who received intravenous BPs had significantly lower Sema4D levels than those who received oral BPs.

CONCLUSION

Serum Sema4D level has predictive value for the onset of MRONJ in BPs users within 12 weeks after dentoalveolar surgery.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Is the Use of Bisphosphonates Putting Horses at Risk? An Osteoclast Perspective

Simple Summary

Bisphosphonates are a group of drugs that intervene in the bone resorption process, producing cellular death of osteoclasts. These drugs are used for skeletal conditions, such as osteoporosis in humans, and are available for veterinary medical use. Clodronate and tiludronate are bisphosphonates approved for the treatment of navicular syndrome in horses over four years old. However, these drugs are sometimes used in juvenile animals under exercise, where osteoclast activity is higher. Bisphosphonate use in juvenile and/or exercising animals could have adverse effects, including maladaptation to exercise or accumulation of microdamage. Furthermore, bisphosphonates can be bound to the skeleton for several years, resulting in a prolonged effect with no pharmaceutical reversal available. This review presents an overview of osteoclast function and a review of bisphosphonate characteristics, mechanisms of action, and side effects in order to contextualize the potential for adverse/side effects in young or exercising animals.

Abstract

Osteoclasts are unique and vital bone cells involved in bone turnover. These cells are active throughout the individual’s life and play an intricate role in growth and remodeling. However, extra-label bisphosphonate use may impair osteoclast function, which could result in skeletal microdamage and impaired healing without commonly associated pain, affecting bone remodeling, fracture healing, and growth. These effects could be heightened when administered to growing and exercising animals. Bisphosphonates (BPs) are unevenly distributed in the skeleton; blood supply and bone turnover rate determine BPs uptake in bone. Currently, there is a critical gap in scientific knowledge surrounding the biological impacts of BP use in exercising animals under two years old. This may have significant welfare ramifications for growing and exercising equids. Therefore, future research should investigate the effects of these drugs on skeletally immature horses.

Bevacizumab and sunitinib mediate osteogenic and pro-inflammatory molecular changes in primary human alveolar osteoblasts in vitro

Antiangiogenic medications target the de novo blood vessel formation in tumorigenesis. However, these novel drugs have been linked to the onset of medication-related osteonecrosis of the jaw (MRONJ). The aim of this in vitro study was to examine the effects of the vascular endothelial growth factor A (VEGFA) antibody bevacizumab (BEV) and the receptor tyrosine kinase inhibitor (RTKI) sunitinib (SUN) on primary human osteoblasts derived from the alveolar bone. Primary human alveolar osteoblasts (HAOBs) were treated with BEV or SUN for 48 h. Cellular metabolic activity was examined by XTT assay. Differentially regulated genes were identified by screening of 22 selected osteogenic and angiogenic markers by quantitative real-time reverse transcriptase polymerase chain reaction (qRT²-PCR). Protein levels of alkaline phosphatase (ALP), collagen type 1, α1 (COL1A1) and secreted protein acidic and cysteine rich (SPARC) were examined by enzyme-linked immunoassay (ELISA). Treatment with BEV and SUN did not exhibit direct cytotoxic effects in HAOBs as confirmed by XTT assay. Of the 22 genes examined by qRT²-PCR, four genes were significantly regulated after BEV treatment and eight genes in the SUN group as compared to the control group. Gene expression levels of ALPL, COL1A1 and SPARC were significantly downregulated by both drugs. Further analysis by ELISA indicated the downregulation of protein levels of ALP, COL1A1 and SPARC in the BEV and SUN groups. The effects of BEV and SUN in HAOBs may be mediated by alterations to osteogenic and catabolic markers. Therapeutic or preventive strategies in MRONJ may address drug-induced depression of osteoblast differentiation.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

Weighted Gene Co-Expression Network Analysis Combined with Machine Learning Validation to Identify Key Modules and Hub Genes Associated with SARS-CoV-2 Infection

The coronavirus disease-2019 (COVID-19) pandemic has caused an enormous loss of lives. Various clinical trials of vaccines and drugs are being conducted worldwide; nevertheless, as of today, no effective drug exists for COVID-19. The identification of key genes and pathways in this disease may lead to finding potential drug targets and biomarkers. Here, we applied weighted gene co-expression network analysis and LIME as an explainable artificial intelligence algorithm to comprehensively characterize transcriptional changes in bronchial epithelium cells (primary human lung epithelium (NHBE) and transformed lung alveolar (A549) cells) during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our study detected a network that significantly correlated to the pathogenicity of COVID-19 infection based on identified hub genes in each cell line separately. The novel hub gene signature that was detected in our study, including PGLYRP4 and HEPHL1, may shed light on the pathogenesis of COVID-19, holding promise for future prognostic and therapeutic approaches. The enrichment analysis of hub genes showed that the most relevant biological process and KEGG pathways were the type I interferon signaling pathway, IL-17 signaling pathway, cytokine-mediated signaling pathway, and defense response to virus categories, all of which play significant roles in restricting viral infection. Moreover, according to the drug-target network, we identified 17 novel FDA-approved candidate drugs, which could potentially be used to treat COVID-19 patients through the regulation of four hub genes of the co-expression network. In conclusion, the aforementioned hub genes might play potential roles in translational medicine and might become promising therapeutic targets. Further in vitro and in vivo experimental studies are needed to evaluate the role of these hub genes in COVID-19.

Abnormalities in Tooth Formation after Early Bisphosphonate Treatment in Children with Osteogenesis Imperfecta

Treatment with intravenous bisphosphonate (BP) in children and adolescents with osteogenesis imperfecta (OI) started in Sweden in 1991. No human studies on the role of BP therapy in development of disturbances in tooth mineralization or tooth morphology have been published. The study cohort comprised 219 individuals who were divided into four groups: group 1, BP treatment onset before 2 years of age (n = 22); group 2, BP treatment onset between 2 and 6 years of age (n = 20); group 3, BP treatment onset between 6 and 10 years of age (n = 13); and a control group of patients with OI who had not received BP therapy (n = 164). The chi-square test was used in between-group comparisons of the prevalence of tooth agenesis. The prevalence of tooth agenesis was significantly higher in children who began BP treatment before the age of 2 years (group 1; 59%,) compared to the controls (10%; p < 0.001) and to children who had begun BP therapy between ages 2 and 6 years (group 2; 10%; p = 0.009) or between ages 6 and 10 years (group 3; 8%; p = 0.003). Different types of disturbances in the enamel formation were seen in 52 premolars, where 51 were seen in those who began BP treatment before the age of 2 years. To conclude, starting BP treatment before the age of 2 years increases the risk of abnormalities in tooth formation manifesting as morphological aberrations, tooth agenesis, and enamel defects.

Bisphosphonates, Bone and Joint Pain

PURPOSE OF REVIEW

Bisphosphonates (BPs) have an established role in a number of diseases including osteoporosis, but the role of BPs for treating symptomatic conditions other than bone metastases is less clear. We review recent data on the efficacy of BPs in the treatment of symptomatic bone and joint pain with osteoarthritis (OA) as an example.

RECENT FINDINGS

Although controversial, BPs have been reported to improve pain ratings, imaging features, and inflammatory markers in patients with arthritis, more specifically OA. It is possible that their effects in periarticular bone strongly influence the complex inflammatory process within the joints. Recent data also suggests that they can potentially impact synovial and synoviocytes and macrophages. Although more studies are needed to define their contribution in clinical practice, increasing evidence suggests they hold an important function, especially in conditions with periarticular bone involvement such as OA. Although BPs are indicated primarily for prevention and treatment of osteoporosis, they can also have potential effects on the inflammatory process of other conditions, including OA. Improvements in pain scale ratings, periarticular findings through imaging, and inflammatory response suggest their potential extra-osteoporotic properties.

In vitro evidence for the involvement of H2S pathway in the effect of clodronate during inflammatory response

Clodronate is a bisphosphonate agent commonly used as anti-osteoporotic drug. Throughout its use, additional anti-inflammatory and analgesic properties have been reported, although the benefits described in the literature could not solely relate to their inhibition of bone resorption. Thus, the purpose of our in vitro study is to investigate whether there are underlying mechanisms explaining the anti-inflammatory effect of clodronate and possibly involving hydrogen sulphide (H₂S). Immortalised fibroblast-like synoviocyte cells (K4IM) were cultured and treated with clodronate in presence of TNF-α. Clodronate significantly modulated iNOS expression elicited by TNF-α. Inflammatory markers induced by TNF-α, including IL-1, IL-6, MCP-1 and RANTES, were also suppressed following administration of clodronate. Furthermore, the reduction in enzymatic biosynthesis of CSE-derived H₂S, together with the reduction in CSE expression associated with TNF-α treatment, was reverted by clodronate, thus rescuing endogenous H₂S pathway activity. Clodronate displays antinflammatory properties through the modulation of H₂S pathway and cytokines levels, thus assuring the control of the inflammatory state. Although further investigation is needed to stress out how clodronate exerts its control on H₂S pathway, here we showed for the first the involvement of H₂S in the additive beneficial effects observed following clodronate therapy.

Lipid homeostasis and mevalonate pathway in COVID-19: Basic concepts and potential therapeutic targets

Despite encouraging progresses achieved in the management of viral diseases, efficient strategies to counteract infections are still required. The current global challenge highlighted the need to develop a rapid and cost-effective strategy to counteract the SARS-CoV-2 pandemic. Lipid metabolism plays a crucial role in viral infections. Viruses can use the host lipid machinery to support their life cycle and to impair the host immune response. The altered expression of mevalonate pathway-related genes, induced by several viruses, assures survival and spread in host tissue. In some infections, statins, HMG-CoA-reductase inhibitors, reduce cholesterol in the plasma membrane of permissive cells resulting in lower viral titers and failure to internalize the virus. Statins can also counteract viral infections through their immunomodulatory, anti-inflammatory and anti-thrombotic effects. Beyond statins, interfering with the mevalonate pathway could have an adjuvant effect in therapies aimed at mitigating endothelial dysfunction and deregulated inflammation in viral infection. In this review we depicted the historical and current evidence highlighting how lipid homeostasis and mevalonate pathway targeting represents a valid approach to rapidly neutralize viruses, focusing our attention to their potential use as effective targets to hinder SARS-CoV-2 morbidity and mortality. Pros and cons of statins and Mevalonate-pathway inhibitors have been also dissected.

Exploiting bone niches: progression of disseminated tumor cells to metastasis

Many solid cancers metastasize to the bone and bone marrow (BM). This process may occur even before the diagnosis of primary tumors, as evidenced by the discovery of disseminated tumor cells (DTCs) in patients without occult malignancies. The cellular fates and metastatic progression of DTCs are determined by complicated interactions between cancer cells and BM niches. Not surprisingly, these niches also play important roles in normal biology, including homeostasis and turnover of skeletal and hematopoiesis systems. In this Review, we summarize recent findings on functions of BM niches in bone metastasis (BoMet), particularly during the early stage of colonization. In light of the rich knowledge of hematopoiesis and osteogenesis, we highlight how DTCs may progress into overt BoMet by taking advantage of niche cells and their activities in tissue turnover, especially those related to immunomodulation and bone repair.

Bisphosphonates, Old Friends of Bones and New Trends in Clinics

Bisphosphonates, used for a long time in osteoporosis management, are currently the target of intensive research, from pre-formulation studies to more advanced stages of clinical practice. This review presents an overview of the contributions of this family of compounds to human health, starting with the chemistry and clinical uses of bisphosphonates. Following this, their pharmacology is described, highlighting administration-borne handicaps and undesirable effects. The last three sections of the review describe the research efforts that seek to curb delivery-related issues and expand bisphosphonate use. Innovative routes and strategies of administration, such as nano-encapsulation for oral intake or injectable cements for local or in-bone delivery are presented, as well as the latest results of case studies or preclinical studies proposing new therapeutic indications for the clinically approved bisphosphonates. Finally, a selection of anti-infectious bisphosphonate new drug candidates is shown, with focus on the molecules reported in the last two decades.

Sequential release of double drug (graded distribution) loaded gelatin microspheres/PMMA bone cement

Drugs are loaded into PMMA bone cement to reduce the risk of infection in freshly implanted prostheses or to promote the differentiation and growth of osteoblasts. However, the same method of loading of drugs in the bone cement cannot simultaneously achieve an effective antibacterial response and long-term treatment outcomes for osteoporosis based on a patient's clinical needs. In the present study, gentamicin sulfate (GS)/alendronate (ALN)-dual-loaded gelatin modified PMMA bone cement (GAPBC) was fabricated to provide rapid and continuous antibiotic release and long-term anti-osteoporotic therapy. Specifically, the gelatin microspheres were loaded with the drugs using separate methodologies, namely, ALN was loaded during fabrication of the gelatin microspheres after which GS was absorbed onto the gelatin from solution. The results demonstrate that sequential release of the GS and ALN was achieved, GS release playing a major role over the first 24 hours and ALN release dominant after 3 weeks of immersion in PBS, resulting from the graded distribution within the gelatin microspheres, and the final drug release ratio of GS (73.6%) and ALN (68.5%) from the modified bone cement was significantly higher than from PMMA bone cement. Therefore, GAPBC represents a potential drug carrier for future clinical applications.

Denosumab Use as a Predictor Variable for External Cervical Resorption: A Case-Control Study

INTRODUCTION

The objective of this case-control study was to investigate the association between denosumab use and the risk of developing external cervical resorption (ECR).

METHODS

Thirty-three patients ≥45 years old who were diagnosed with ECR were selected. Controls were matched to the cases based on sex and age (±5 years) in a 1:1 ratio. Confounders were classified into systemic factors, including a history of systemic sclerosis, hepatitis B, denosumab use, and bisphosphonate use, or local factors, including a history of traumatic occlusion, periodontal procedures (scaling and root planing and periodontal surgeries), and tooth extraction (excluding third molar extraction). Additionally, the number of remaining teeth in each subject was recorded using panoramic radiographs. The baseline characteristics of the 2 groups, including age, sex, and the number of remaining teeth, were compared using the chi-square and Mann-Whitney U tests. Binary logistic regression was used to determine the possible association between denosumab use and the risk of developing ECR (α < 0.05).

RESULTS

No significant differences in baseline characteristics were observed between the case and control groups (P > .05). After adjusting for systemic and local cofounders, denosumab use was significantly associated with the occurrence of ECR (odds ratio = 7.317; 95% confidence interval, 1.410-37.966; P < .05).

CONCLUSIONS

Based on the binary logistic regression model, denosumab use could significantly predict the risk of developing ECR.

The NLRP3 inflammasome regulates adipose tissue metabolism

Adipose tissue regulates metabolic homeostasis by participating in endocrine and immune responses in addition to storing and releasing lipids from adipocytes. Obesity skews adipose tissue adipokine responses and degrades the coordination of adipocyte lipogenesis and lipolysis. These defects in adipose tissue metabolism can promote ectopic lipid deposition and inflammation in insulin-sensitive tissues such as skeletal muscle and liver. Sustained caloric excess can expand white adipose tissue to a point of maladaptation exacerbating both local and systemic inflammation. Multiple sources, instigators and propagators of adipose tissue inflammation occur during obesity. Cross-talk between professional immune cells (i.e. macrophages) and metabolic cells (i.e. adipocytes) promote adipose tissue inflammation during metabolic stress (i.e. metaflammation). Metabolic stress and endogenous danger signals can engage pathogen recognition receptors (PRRs) of the innate immune system thereby activating pro-inflammatory and stress pathways in adipose tissue. The Nod-like receptor protein 3 (NLRP3) inflammasome can act as a metabolic danger sensor to a wide range of pathogen- and damage-associated molecular patterns (PAMPs and DAMPs). Activation of the NLRP3 inflammasome facilitates caspase-1 dependent production of the pro-inflammatory cytokines IL-1β and IL-18. Activation of the NLRP3 inflammasome can promote inflammation and pyroptotic cell death, but caspase-1 is also involved in adipogenesis. This review discusses the role of the NLRP3 inflammasome in adipose tissue immunometabolism responses relevant to metabolic disease. Understanding the potential sources of NLRP3 activation and consequences of NLRP3 effectors may reveal therapeutic opportunities to break or fine-tune the connection between metabolism and inflammation in adipose tissue during obesity.

Delayed alveolar bone repair and osteonecrosis associated with Zoledronic Acid therapy in rats: macroscopic, microscopic and molecular analysis

Objective

This study aims to evaluate bone repair and the development of the medication related osteonecrosis of the jaw (MRONJ) associated with the use of zoledronic acid in Wistar rats.

Methodology

48 male Wistar rats were divided into four groups: ZA, treated with intraperitoneal zoledronic acid, 0.6 mg/kg every 28 days, totaling five doses; control (C), treated with 0.9% sodium chloride; ZA-surgical (SZA) and C-surgical (SC), submitted to extraction of the right upper molars 45 days after the first application. Alveolar bone repair was evaluated by macroscopic and histological analysis. Protein expression evaluations were performed by qPCR.

Results

Macroscopic evaluation showed that 91.66% (11) of the animals in the SZA group and 41.66% (5) from the SC group presented solution of epithelium continuity (P<0.05). All animals in the SZA group and none in the SC group had bone sequestration. The area of osteonecrosis was higher in the SZA group than in the SC group (P<0.05). In molecular evaluation, the SZA group presented changes in the expression of markers for osteoclasts, with increased RANK and RANKL, and a decrease in OPG.

Conclusion

The results highlighted strong and evident interference of zoledronic acid in bone repair of the socket, causing osteonecrosis and delayed bone remodeling.

Cellulose nanocrystals: a multimodal tool to enhance the targeted drug delivery against bone disorders

Aim: We investigated the use of cellulose nanocrystals (CNCs) as drug nanocarriers combining an anti-osteoporotic agent, alendronate (ALN), and an anti-cancer drug, doxorubicin (DOX). Materials & methods: CNC physicochemical characterization, in vivo imaging coupled with histology and in vitro uptake and toxicity assays were carried out. Results: In vivo CNC-ALN did not modify bone tropism and lung penetration, whereas its liver and kidney accumulation was slightly higher compared with CNCs alone. In vitro studies showed that CNC-ALN did not impair ALN's effect on osteoclasts, whereas CNC-DOX confirmed the therapeutic potential against bone metastatic cancer cells. Conclusions: This study provides robust proof of the potential of CNCs as easy, flexible and specific carriers to deliver compounds to the bone.

Atypical femoral neck fracture after prolonged bisphosphonate therapy

Of the drugs developed to prevent and treat osteoporosis, bisphosphonate has played a very important role in preventing osteoporotic fractures. However, case reports describing atypical femoral fractures in patients using long-term bisphosphonates have emerged. The majority of atypical femur fractures occurs in the lateral aspect of the subtrochanteric or femur diaphysis, which is explained by accumulation of tensile stress in these areas. Although the superior cortex of the femur neck withstands maximum tensile stress, to our knowledge, there have been only two reports (three cases) of atypical femoral neck fracture. In addition, none of those case reports revealed detailed pathology related to suppressed bone turnover rate. We encountered an incomplete femoral neck fracture and diagnosed it as "atypical" on the basis of the patient's lack of trauma and medication history and pathological findings. For patients with groin pain, minimal or no trauma, and a history of long-term bisphosphonate use, an atypical femoral neck fracture should be considered.

Structure-Dependent Effects of Bisphosphonates on Inflammatory Responses in Cultured Neonatal Mouse Calvaria

Bisphosphonates (BPs) are classified into two groups, according to their side chain structures, as nitrogen-containing BPs (NBPs) and non-nitrogen-containing BPs (non-NBPs). In this study, we examined the effects of NBPs and non-NBPs on inflammatory responses, by quantifying the inflammatory mediators, prostaglandin E₂ (PGE₂) and nitric oxide (NO), in cultured neonatal mouse calvaria. All examined NBPs (pamidronate, alendronate, incadronate, risedronate, zoledronate) stimulated lipopolysaccharide (LPS)-induced PGE₂ and NO production by upregulating COX-2 and iNOS mRNA expression, whereas non-NBPs (etidronate, clodronate, tiludronate) suppressed PGE₂ and NO production, by downregulating gene expression. Additionally, [4-(methylthio) phenylthio] methane bisphosphonate (MPMBP), a novel non-NBP with an antioxidant methylthio phenylthio group in its side chain, exhibited the most potent anti-inflammatory activity among non-NBPs. Furthermore, results of immunohistochemistry showed that the nuclear translocation of NF-κB/p65 and tyrosine nitration of cytoplasmic protein were stimulated by zoledronate, while MPMBP inhibited these phenomena, by acting as a superoxide anion (O₂⁻) scavenger. These findings indicate that MPMBP can act as an efficacious agent that causes fewer adverse effects in patients with inflammatory bone diseases, including periodontitis and rheumatoid arthritis.

Zoledronic acid inhibits the growth of leukemic MLL-AF9 transformed hematopoietic cells

A leukemic in vitro model produced by transducing Cord Blood derived-hematopoietic CD34⁺ cells with the MLL-AF9 translocation resulting in the oncogenic fusion protein, is used to assess for sensitivity to Zoledronic acid. These cells are practically immortalized and are of myeloid origin. Proliferation, clonogenic and stromal co-culture assays showed that the MLL-AF9 cells were considerably more sensitive to Zoledronic acid than normal hematopoietic CD34⁺ cells or MS-5 stromal cells. The MLL-AF9 cells were notably more inhibited by Zoledronic acid when cultured as colonies in 3 dimensions, requiring cell-cell contacts compared to suspension expansion cultures. This is coherent with the mechanism of action of Zoledronic acid inhibiting farnesyl diphosphate synthase which results in a block in prenylation of GTPases such that their role in the membrane is compromised for cell-cell contacts. Zoledronic acid can be proposed to target the MLL-AF9 leukemic stem cells before they emerge from the hematopoietic niche, which being in proximity to bone osteoclasts where Zoledronic acid is sequestered can be predicted to result in sufficient levels to result in an anti-leukemic action.

Bisphosphonate-Based Molecules as Potential New Antiparasitic Drugs

Neglected tropical diseases such as Chagas disease and leishmaniasis affect millions of people around the world. Both diseases affect various parts of the globe and drugs traditionally used in therapy against these diseases have limitations, especially with regard to low efficacy and high toxicity. In this context, the class of bisphosphonate-based compounds has made significant advances regarding the chemical synthesis process as well as the pharmacological properties attributed to these compounds. Among this spectrum of pharmacological activity, bisphosphonate compounds with antiparasitic activity stand out, especially in the treatment of Chagas disease and leishmaniasis caused by Trypanosoma cruzi and Leishmania spp., respectively. Some bisphosphonate compounds can inhibit the mevalonate pathway, an essential metabolic pathway, by interfering with the synthesis of ergosterol, a sterol responsible for the growth and viability of these parasites. Therefore, this review aims to present the information about the importance of these compounds as antiparasitic agents and as potential new drugs to treat Chagas disease and leishmaniasis.

Pamidronate in chronic non-bacterial osteomyelitis: a randomized, double-blinded, placebo-controlled pilot trial

OBJECTIVE

This is the first randomized double-blinded, placebo-controlled pilot trial to investigate the efficacy of pamidronate in reducing radiological and clinical disease activity in chronic non-bacterial osteomyelitis (CNO).

METHOD

Patients received pamidronate or placebo at baseline and weeks 12 and 24. Whole-body magnetic resonance imaging was performed at baseline and weeks 12 and 36, and computed tomography of the anterior chest wall (ACW) at baseline and week 36. Radiological disease activity was systematically scored in the ACW and spine. Patient-reported outcomes [visual analogue scale (VAS) pain, VAS global health, Health Assessment Questionnaire (HAQ), EuroQol-5 Dimensions (EQ-5D), and 36-item Short-Form Health Survey (SF-36)] and biomarkers of bone turnover and inflammation were assessed at baseline and weeks 1, 4, 12, 24, and 36. Data are expressed as median [interquartile range].

RESULTS

Fourteen patients were randomized and 12 were analysed. From baseline to week 36, the radiological disease activity score in the ACW decreased from 5 [4-7] to 2.5 [1-3] in the pamidronate group, but did not change in the placebo group (p = 0.04). From baseline to week 36, VAS pain and VAS global health tended to decrease more in the pamidronate than in the placebo group (p = 0.11, p = 0.08). Physical functioning (HAQ) and health-related quality of life (EQ-5D, SF-36) did not change. Biomarkers of bone turnover decreased only in the pamidronate group (p ≤ 0.02).

CONCLUSION

Pamidronate may improve radiological and clinical disease activity in CNO. Methods to score radiological disease activity in adult CNO were suggested. Clinical Trials: NCT02594878.

Short-term high-dose zoledronic acid enhances crystallinity in mandibular alveolar bone in rats

Owing to its antiresorptive properties, zoledronic acid (ZOL) is commonly used in the management of benign as well as malignant bone diseases. This molecule targets sites where bone is actively remodeling, and high concentrations have been reported in the jaw. The purpose of this study was to investigate whether treatment of male rats with ZOL, at a dosage equivalent to that used for antitumor treatment, impacts the short-term qualitative properties of mandibular bone independent of bone remodeling. Thirty rats were randomly assigned to treatment either with ZOL or with serum-vehicle (control) (weekly injections: 100 μg kg^-1 for 6 wk, n = 15 per group). Using the tetracycline double-labeling technique, remodeled bone areas, corresponding to the preferential site of bisphosphonate binding, were found in the alveolar bone along the alveolar bone proper. The composition of bone in these areas was characterized using Raman microspectroscopy and compared with adjacent, non-remodeled, older bone. The ZOL-treated group exhibited higher crystallinity in the remodeled bone areas (+2%), reflecting an early maturation of the apatite mineral after ZOL injection. Our findings highlight a direct and rapid effect of clinically relevant anti-tumoral ZOL doses on the qualitative properties of mandibular bone, especially on mineral crystallinity in the vicinity of the teeth, namely, the alveolar bone proper.

Awareness among patient at risk of developing Medication Related Osteonecrosis of the Jaw (MRONJ) - A primary prevention strategy

The quality of life, in itself, in cancer patients or in osteoporotic individuals, without even considering the side effects of the medication in the first place, has a considerable negative impact on the clinical outcome. The Medication Related Osteonecrosis of the Jaw (MRONJ), in the maxillofacial region, although rare, needs to be addressed with the prime importance. One of the key components of any given preventive treatment strategy is to, create awareness about the medication related unwanted effects, among health care professionals and patients.

Objective

This study is aimed to explore and assess the awareness level among dental patients about MRONJ, the risk factors, and the high-risk category (who are prone to develop MRONJ).

Material and methods

This is a prospective interviewer administered research electronic data capture (REDCap) survey. The sample included 68 patients, who are currently taking or will be taking Bisphosphonate (BP), and/or Denosumab, and anti-Angiogenic agent. Data have been analyzed using IBM SPSS software,

Results

Sixty-eight patients (18 males and 50 females), participated in this study. Only 23 subjects (33.82%) were aware about the MRONJ. Females were more aware about the complications than males. The awareness among the subjects with education at college level appears to be higher than the subjects having education less than high school level. Even though, a dental check- up, is mandatory, prior to starting these medications, to see if any dental treatment is required, only slightly more than half of the patients (54.72%) had a dental checkup.

Conclusion

This is a novel study in the Middle- East, used to assess awareness about the MRONJ including three type of related medications. Low awareness of MRONJ is alarming. The results of the study will help to initiate the process of providing the education materials, about the side effects and importance of oral hygiene maintenance, giving priority to improve the quality of life in such patients. Awareness of patients regarding the complications must be an important part of health care practice guidelines.

Pamidronate: A model compound of the pharmacology of nitrogen-containing bisphosphonates; A Leiden historical perspective

Pamidronate [3-amino-1-hydroxypropylidene-1,1-bisphosphonate (APD)] was the first nitrogen-containing bisphosphonate (N-BP) investigated in clinical studies. In contrast to other clinically used bisphosphonates, pamidronate was discovered and its properties were initially studied in an Academic Institution. On the occasion of the 50th Anniversary of the first publications on the biological effects of bisphosphonates, I review in this article the contribution of Leiden investigators to the development of pamidronate that led to the recognition of the significance of the Nitrogen atom in the side chain of bisphosphonates for their action on bone resorption and to the formulation of principles for the use of N-BPs in the management of patients with different skeletal disorders.

Biofunctionalization of Textile Materials. 2. Antimicrobial Modification of Poly(lactide) (PLA) Nonwoven Fabricsby Fosfomycin

This research is focused on obtaining antimicrobial hybrid materials consisting of poly(lactide) nonwoven fabrics and using phosphoro-organic compound—fosfomycin—as a coating and modifying agent. Polylactide (PLA) presents biodegradable polymer with multifunctional application, widely engaged in medical related areas. Fosfomycin as functionalized phosphonates presents antibiotic properties expressed by broad spectrum of antimicrobial properties. The analysis of these biofunctionalized nonwoven fabrics processed by the melt-blown technique, included: scanning electron microscopy (SEM), UV/VIS transmittance, FTIR spectrometry, air permeability. The functionalized nonwovens were tested on microbial activity tests against colonies of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria.

Racial difference in bioavailability of oral ibandronate between Caucasian and Taiwanese postmenopausal women

Following 150 mg of oral ibandronate, Taiwanese females have greater serum and urine levels of this drug and bone resorption marker suppression than Caucasian women. These inter-ethnic differences seems to be partly explained by a 2.48-fold higher bioavailability of ibandronate in Taiwanese postmenopausal women.

INTRODUCTION

Interethnic differences in the pharmacokinetics of oral ibandronate for osteoporosis are unknown. We compared the disposition of oral ibandronate between Caucasian and Taiwanese postmenopausal women.

METHODS

Ibandronate 150 mg was administered to 35 Caucasian and 16 Taiwanese postmenopausal women in two separate phase 1 studies. Interethnic comparisons were performed to assess pharmacokinetic properties, including the area under the concentration-time curve (AUC), peak concentration (Cmax), elimination half-life, urinary drug recovery (Ae%), renal clearance (CLr), apparent total clearance (CL/F), and apparent volume of distribution (Vd/F).

RESULTS

The mean AUC, Cmax, and Ae% were 2.41-, 1.69-, and 2.95-fold greater in the Taiwanese than in the Caucasian subjects, and the average CL/F and Vd/F were 2.48- and 2.46-fold smaller. There were no significant differences in mean CLr and half-life between both groups. As bisphosphonates are not biotransformed but are mainly excreted in the urine, the total body clearance is close to the CLr. These results suggested a larger bioavailability in the Taiwanese group which resulted in the differences in the CL/F and Vd/F. Multiple linear regression analysis demonstrated ethnicity influences of the pharmacokinetic properties after adjusting for the other variables.

CONCLUSIONS

Bioavailability was largely responsible for the interethnic pharmacokinetic differences following oral administration of 150 mg ibandronate and seemed greater in the Taiwanese compared with the Caucasian subjects. Further dose-ranging studies are warranted to determine the optimal dosages of oral ibandronate in patients of Asian or Taiwanese ethnicity.

Targeting prenylation inhibition through the mevalonate pathway

Protein prenylation is a critical mediator in several diseases including cancer and acquired immunodeficiency syndrome (AIDS). Therapeutic intervention has focused primarily on directly targeting the prenyltransferase enzymes, FTase and GGTase I and II. To date, several drugs have advanced to clinical trials and while promising, they have yet to gain approval in a medical setting due to off-target effects and compensatory mechanisms activated by the body which results in drug resistance. While the development of dual inhibitors has mitigated undesirable side effects, potency remains sub-optimal for clinical development. An alternative approach involves antagonizing the upstream mevalonate pathway enzymes, FPPS and GGPPS, which mediate prenylation as well as cholesterol synthesis. The development of these inhibitors presents novel opportunities for dual inhibition of cancer-driven prenylation as well as cholesterol accumulation. Herein, we highlight progress towards the development of inhibitors against the prenylation machinery.

Clinical evidence of the effect of bisphosphonates on pregnancy and the infant

Bisphosphonates (BPs) are potent inhibitors of osteoclast mediated bone resorption. These drugs are widely used in the management of osteoporosis and other diseases, characterized by high bone turnover. The effect of BPs on gestation and lactation, when they are used as therapeutic agents in premenopausal women, is yet unknown. We conducted a detailed literature review and identified the cases of BPs use in young women, as well as, the effects of this therapy on the gestation and the embryo. The published data, regarding the use of BPs in premenopausal women and their effects on the pregnancy outcome, are limited. However, we could identify the outcomes of 40 pregnant women, who had received BPs prior to or during pregnancy, that have been documented in the literature. All women had valid indications to receive BPs for serious bone metabolism conditions. We could not identify any prospective trials, which focus on pregnancy outcomes following after the in-utero exposure to BPs. In total, no serious adverse effects were reported. Problems related to the offspring, such as hypocalcemia and a tendency for low body weight (LBW), were self-resolving. In addition, no serious adverse outcomes were reported for women having completed pregnancy. Nevertheless, follow-up was limited for both outcomes suggesting the necessity of national and international registries.

Bisphosphonates-much more than only drugs for bone diseases

α,α-Bisphosphonates (BPs) are well established in the treatment of bone diseases such as osteoporosis and Paget's disease. Their successful application originates from their high affinity to hydroxyapatite. While the initially appreciated features of BPs are already beneficial to many patients, recent developments have further expanded their pleiotropic applications. This review describes the background of the interactions of BPs with bone cells that form the basis of the classical treatment. A better understanding of the mechanism behind their interactions allows for the parallel application of BPs against bone cancer and metastases followed by palliative pain relief. Targeted therapy with bone-seeking BPs coupled with a diagnostic agent in one particle resulted in theranostics which is also described here. For example, in such a system, BP moieties are bound to contrast agents used in magnetic resonance imaging or radionuclides used in positron emission tomography. In addition, another example of the pleiotropic function of BPs which involves targeting the imaging agents to bone tissues accompanied by pain reduction is presented in this work.

Association Between Drug Treatments for Patients With Osteoporosis and Overall Mortality Rates: A Meta-analysis

IMPORTANCE

Previous studies have reported that drug treatments, particularly treatment with bisphosphonates, is associated with reduced overall mortality rates in addition to decreased fracture risk. If so, drug treatments should be recommended for this reason alone, regardless of a patient's risk of fracture.

OBJECTIVE

To assess whether randomized clinical trials demonstrate that treatment with bisphosphonates, particularly zoledronate, is associated with reduced mortality rates.

DATA SOURCES

Science Direct, MEDLINE, Embase, and the Cochrane Library were searched for randomized placebo-controlled clinical trials of drug treatments for osteoporosis published after 2009 and published or in press before April 19, 2019. Conference abstracts from annual osteoporosis society meetings were also included in the search.

STUDY SELECTION

Included studies were clinical trials that (1) were randomized and placebo-controlled; (2) studied drug treatments with proven antifracture efficacy; (3) used agents at the approved dose for treatment of osteoporosis; and (4) had a duration of 1 year or more. Abstracts from the literature searches were reviewed for inclusion and exclusion criteria, and mortality rate data were abstracted from the article by 1 researcher and validated by a second. A total of 2045 records were screened; 38 (1.8%) were included in the meta-analyses.

DATA EXTRACTION AND SYNTHESIS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist was followed for abstracting data and assessing data quality and validity. Data were pooled using random-effects models, and between-study variability was assessed using the I2 index. The risk of bias for each study was assessed, and funnel plots and Egger and Begg statistics were used to evaluate publication bias.

MAIN OUTCOMES AND MEASURES

Associations of all drug treatments, particularly bisphosphonate and zoledronate treatments, with overall mortality.

RESULTS

Of 38 clinical trials that included 101 642 unique participants, 38 were included in the meta-analyses of all drug treatments (45 594 participants randomized to placebo; 56 048 to treatment); 21 clinical trials, of bisphosphonate treatments (20 244 participants randomized to placebo; 22 623 to treatment); and 6 clinical trials, of zoledronate treatments (6944 participants randomized to placebo; 6926 to treatment). No significant association was found between all drug treatments for osteoporosis and overall mortality rate (risk ratio [RR], 0.98; 95% CI, 0.91-1.05; I2 = 0%). Clinical trials of bisphosphonate treatment (RR, 0.95; 95% CI, 0.86-1.04) showed no significant association with overall mortality. Also, clinical trials of zoledronate treatment (RR, 0.88; 95% CI, 0.68-1.13) showed no association with overall mortality rate; however, evidence existed for heterogeneity of the results (I2 = 48.2%).

CONCLUSIONS AND RELEVANCE

Results of this meta-analysis suggest that bisphosphonate treatment may not be associated with reduced overall mortality rates in addition to decreased fracture risk and should only be recommended to reduce fracture risk. Additional trials are needed to clarify whether treatment with zoledronate reduces mortality rates.

BIOLOGICAL ENHANCEMENTS FOR ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The anterior cruciate ligament (ACL) is mostly responsible for providing knee stability. ACL injury has a marked effect on daily activities, causing pain, dysfunction, and elevated healthcare costs. ACL reconstruction (ACLR) is the standard treatment for this injury. However, despite good results, ACLR is associated with a significant rate of failure. In this context, the mechanical and biological causes must be considered. From a biological perspective, the ACLR depends on the osseointegration of the graft in the adjacent bone and the process of intra-articular ligamentization for good results. Here, we discuss the mechanisms underlying the normal graft healing process after ACLR and its biological modulation, thus, presenting novel strategies for biological enhancements of the ACL graft. Level of evidence III, Systematic review of level III studies.

Histological evaluation of the healing process of autografted mandibular bone defects in rats under treatment with zoledronate

OBJECTIVE

This study aims to evaluate the healing process of autografted mandibular bone defects in rats treated with zoledronate (ZOL).

SUBJECTS AND METHODS

A total of 180 Wistar rats were divided into four groups: group L received intravenous infusion of two doses of 0.06 mg/kg ZOL, nine weeks apart; group H received 0.06 mg/kg ZOL, while groups C and NC received normal saline at three-week intervals for nine weeks. Three weeks following the last infusion, a unilateral mandibular bone defect (5 mm) was created. Except in the NC group, all defects were repaired with autologous iliac bone graft. Fifteen animals from each group were sacrificed on postoperative Day 20, Day 40, and Day 60. Graft healing was scored using a histological grading system (ranging from 1 to 6).

RESULTS

Histological evaluations performed on postoperative Day 60 showed that the mandibular defects were mainly repaired with fibrous tissue in the NC and H groups (93.00% ± 7.51% and 82.67% ± 13.08%, respectively) and with bone in the C and L groups (75.33% ± 14.20% and 92.67% ± 8.84%, respectively). The percentage of fibrous tissue and bone as well as the healing score of the NC and H groups were significantly different (P = 0.001) from those of the C and L groups. However, these were not different between neither the NC and H groups nor the C and L groups.

CONCLUSION

Based on the results of the present study the hypothesis can be established that there also might be a dose-dependent effect of ZOL on the healing of bone grafts in humans. This hypothesis has to be verified or rejected in clinical trials.

A Multifunctional Therapy Approach for Cancer: Targeting Raf1- Mediated Inhibition of Cell Motility, Growth, and Interaction with the Microenvironment

Prostate cancer cells move from their primary site of origin, interact with a distant microenvironment, grow, and thereby cause death. It had heretofore not been possible to selectively inhibit cancer cell motility. Our group has recently shown that inhibition of intracellular activation of Raf1 with the small-molecule therapeutic KBU2046 permits, for the first time, selective inhibition of cell motility. We hypothesized that simultaneous disruption of multiple distinct functions that drive progression of prostate cancer to induce death would result in advanced disease control. Using a murine orthotopic implantation model of human prostate cancer metastasis, we demonstrate that combined treatment with KBU2046 and docetaxel retains docetaxel's antitumor action, but provides improved inhibition of metastasis, compared with monotherapy. KBU2046 does not interfere with hormone therapy, inclusive of enzalutamide-mediated inhibition of androgen receptor (AR) function and cell growth inhibition, and inclusive of the ability of castration to inhibit LNCaP-AR cell outgrowth in mice. Cell movement is necessary for osteoclast-mediated bone degradation. KBU2046 inhibits Raf1 and its downstream activation of MEK1/2 and ERK1/2 in osteoclasts, inhibiting cytoskeleton rearrangement, resorptive cavity formation, and bone destruction in vitro, with improved effects observed when the bone microenvironment is chemically modified by pretreatment with zoledronic acid. Using a murine cardiac injection model of human prostate cancer bone destruction quantified by CT, KBU2046 plus zoledronic exhibit improved inhibitory efficacy, compared with monotherapy. The combined disruption of pathways that drive cell movement, interaction with bone, and growth constitutes a multifunctional targeting strategy that provides advanced disease control.

Bisphosphonate treatment changes regional distribution of trabecular microstructure in human lumbar vertebrae

BACKGROUND

In osteoporosis patients, antiresorptive treatments such as alendronate reduce the resorption of trabecular bone and thus minimize vertebral fracture risk. However, fracture risk reduction efficacy of antiresorptive drugs varies between skeletal sites and is highest for vertebral bone. In human vertebrae, cancellous bone is distributed heterogeneously between regions. This microstructural heterogeneity is changing with patient age and is likely to play a major role in vertebral failure mechanisms and fracture susceptibility. Whether antiresorptive treatment affects the heterogeneity of vertebral microstructure in osteoporosis has not been unraveled.

METHODS

Our aim was to assess whether antiresorptive treatment would have a region-dependent influence on vertebral trabecular bone. Therefore, we used high-resolution peripheral quantitative computed tomography (HR-pQCT), microcomputed tomography (microCT) and uniaxial compression testing to determine the structure and mechanical properties of trabecular bone cores from anterior and posterior regions of 22 lumbar vertebrae from elderly osteoporotic women. We analyzed age-matched ex vivo bone samples from bisphosphonate-treated female osteoporosis patients (age: 82 ± 7y, bisphosphonate treatment period: 4 ± 2 years) along treatment-naïve female controls (82 ± 7y).

RESULTS

MicroCT analysis showed a significantly lower bone volume fraction (p = 0.006) and lower trabecular number (p = 0.003) for the anterior bone cores compared to posterior bone cores in the treatment-naïve group. The bisphosphonate-treated group had a more homogeneous bone volume distribution and did not show significant regional differences in bone volume, it however also displayed significantly different trabecular numbers (p = 0.016). In bone cores of the bisphosphonate-treated group, trabeculae were thicker in comparison to treatment-naïve controls (p = 0.011). Differences in bone volume further resulted in different maximum forces during compression testing between the samples. In addition, the percental difference between BV/TV_μCT in anterior and posterior bone cores was lower in bisphosphonate-treated vertebrae when vertebrae with directly adjacent fractures (n = 3) were excluded.

CONCLUSION

In conclusion, regional trabecular bone microstructure in lumbar vertebrae of bisphosphonate-treated women was more homogeneous compared to treatment-naïve controls. Bisphosphonate treatment, which specifically targets resorption surfaces common in anterior vertebral bone, might have resulted in a region-specific preservation of vertebral microstructure and loading capacity. This could have positive implications for the reduction of wedge fracture risk and add to the explanation of the higher efficacy of fracture risk reduction in vertebrae in comparison to other fracture regions.

Bisphosphonate use and incident cardiovascular events among older breast cancer survivors

BACKGROUND

Cardiovascular disease (CVD) is a leading cause of mortality in early-stage breast cancer survivors. Recent studies suggest that bisphosphonates may decrease CVD risk in older patients.

OBJECTIVE

This study sought to assess whether bisphosphonate use is associated with lower rates of incident CVD events among early-stage breast cancer survivors.

METHODS

Longitudinal, population-based cohort study was conducted by using data from the Surveillance, Epidemiology and End Results registry linked to Medicare claims. We identified women >65 years with no history of CVD who were diagnosed with stage 0-III primary breast cancer between 2007 and 2010. Our primary outcome was a composite of incident angina pectoris, myocardial infarction, atrial fibrillation/flutter, heart failure, or stroke within 36 months of cancer diagnosis. Bisphosphonate use was defined as the presence of ≥1 pharmacy claim from 6 months prior to cancer diagnosis to the incident CVD event. We used propensity scores to create a matched group of breast cancer survivors without bisphosphonate exposure to compare rates of incident CVD events.

RESULTS

A total of 2178 breast cancer survivors had ≥1 bisphosphonate prescription; the average length of bisphosphonate use was 15 months. Analyses of the matched data showed that 13.0% of bisphosphonate users and 23.4% of non-bisphosphonate users experienced an incident CVD event (p < 0.0001) after breast cancer diagnosis. Bisphosphonate use was significantly associated with fewer incident CVD events (hazard ratio: 0.51, 95% confidence interval: 0.44 to 0.59).

CONCLUSIONS

Bisphosphonate use is associated with lower incidence of CVD events among older early-stage breast cancer survivors. Future studies should prospectively evaluate whether bisphosphonate use can decrease CVD incidence.

Pharmacology of bisphosphonates in pain

The treatment of pain, in particular, chronic pain, remains a clinical challenge. This is particularly true for pain associated with severe or rare conditions, such as bone cancer pain, vulvodynia, or complex regional pain syndrome. Over the recent years, there is an increasing interest in the potential of bisphosphonates in the treatment of pain, although there are few papers describing antinociceptive and anti-hypersensitizing effects of bisphosphonates in various animal models of pain. There is also increasing evidence for clinical efficacy of bisphosphonates in chronic pain states, although the number of well-controlled studies is still limited. However, the mechanisms underlying the analgesic effects of bisphosphonates are still largely elusive. This review provides an overview of preclinical and clinical studies of bisphosphonates in pain and discusses various pharmacological mechanisms that have been postulated to explain their analgesic effects. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.