Bisphosphonate treatment for children with disabling conditions

Mild antiresorptive activity of an anti-vascular endothelial growth factor A antibody and sunitinib in a rat model of bone resorption

Medication-Related-Osteonecrosis-of-the-Jaw (MRONJ) is an adverse event linked to antiresorptives such as bisphosphonates and denosumab. While MRONJ predominantly affects cancer patients treated with these agents, it has been less frequently reported in cancer patients receiving angiogenesis inhibitors (AgIs) like bevacizumab and sunitinib, even without concurrent use of antiresorptives. We hypothesized that certain AgIs exhibit antiresorptive activity in addition to their antiangiogenic effects, potentially influencing the pathophysiology of MRONJ. 52 five-week-old SD rats were randomized to receive vehicle (VEH), an oncologic dose of zoledronic acid (ZOL), or low (LD) and high doses (HD) of either an anti-VEGFA antibody or sunitinib (SU) for 10 days. We used the Schenk assay to assess the in vivo antiresorptive properties of these drugs/agents. We evaluated serum biomarkers of bone resorption (TRACP 5b) and formation (P1NP), pQCT variables of the femurs/tibias, and bone resorption/formation variables by bone histomorphometry at the distal femur metaphysis. ZOL reduced TRACP-5b levels, osteoclast number, and BFR while increasing vBMD, mineralized tissue volume, calcified cartilage volume, and bone volume. Both anti-VEGFA and SU decreased osteoclast number and increased calcified cartilage volume relative to total mineralized tissue volume, though to a lesser extent than ZOL. Anti-VEGFA (HD) also reduced TRACP-5b levels. Furthermore, both AgIs decreased P1NP levels, MAR, and bone elongation rate but increased growth cartilage thickness and induced physeal dysplasia. In conclusion, AgIs, particularly anti-VEGFA, exhibit significant yet milder antiresorptive activity compared to ZOL. They also affect bone formation, suggesting a complex mechanism that may play a role in the pathophysiology of MRONJ.

Can AI reveal the next generation of high-impact bone genomics targets?

Genetic studies have revealed hundreds of loci associated with bone-related phenotypes, including bone mineral density (BMD) and fracture risk. However, translating discovered loci into effective new therapies remains challenging. We review success stories including PCSK9-related drugs in cardiovascular disease and evidence supporting the use of human genetics to guide drug discovery, while highlighting advances in artificial intelligence and machine learning with the potential to improve target discovery in skeletal biology. These strategies are poised to improve how we integrate diverse data types, from genetic and electronic health records data to single-cell profiles and knowledge graphs. Such emerging computational methods can position bone genomics for a future of more precise, effective treatments, ultimately improving the outcomes for patients with common and rare skeletal disorders.

Bone alterations of pamidronate therapy in children with cerebral palsy complicating orthopedic management

Cerebral palsy (CP) is a heterogeneous group of disorders with different clinical types and underlying genetic variants. Children with CP are at risk for fragility fractures secondary to low bone mineral density, and although bisphosphonates are prescribed for the treatment of children with bone fragility, there is limited information on long-term bone impact and safety. Children with CP usually present overtubulated bones, and the thickening of cortical bone by pamidronate treatment can potentially further narrow the medullary canal. Our purpose was to report bone alterations attributable to pamidronate therapy that impact orthopedic care in children with CP. The study consisted of 41 children with CP treated with pamidronate for low bone mineral density from 2006 to 2020. Six children presented unique bone deformities and unusual radiologic features attributed to pamidronate treatment, which affected their orthopedic care. The cases included narrowing of the medullary canal and sclerotic bone, atypical femoral fracture, and heterotopic ossification. Treatment with bisphosphonate reduced the number of fractures from 101 in the pretreatment period to seven in the post-treatment period ( P  < 0.001). In conclusion, children with CP treated with bisphosphonate have a reduction in low-energy fractures; however, some fractures still happen, and pamidronate treatment can lead to bone alterations including medullary canal narrowing with sclerotic bone and atypical femoral fractures. In very young children, failure to remodel may lead to thin, large femoral shafts with cystic medullary canals. More widespread use of bisphosphonates in children with CP may make these bone alterations more frequent. Level of evidence: Level IV: Case series with post-test outcomes.

Bisphosphonates and osteonecrosis of the jaws: Clinical and forensic aspects

OBJECTIVE

This manuscript aims to provide a comprehensive review of the current knowledge in the pathophysiology, diagnosis, prevention, and other relevant clinical and forensic aspects of a potentially severe complication known as medication-related osteonecrosis of the jaw (MRONJ) while synthesizing state-of-the-art information on bisphosphonates and introducing a possible differential diagnosis.

DESIGN

An extensive search was conducted in PubMed (U.S. National Library of Medicine) without a time or language constraint, focusing on the epidemiology, pathophysiology, risk factors, site specificity, signs and symptoms, differential diagnosis, prevention, and forensic aspects of MRONJ. All types of original articles, reviews, case reports, short communications, opinion articles, guidelines, and letters to editors were considered to produce a complete review on this subject.

RESULTS

MRONJ prevention relies on a multidisciplinary approach and is critical since truly effective treatments are lacking. This therapeutic challenge is partly due to uncertainty regarding this condition's pathophysiology. Differential diagnosis of osteonecrosis of the jaws associated with krokodil abuse, one of the most dangerous and homemade psychoactive illicit substances, should be considered.

CONCLUSIONS

Further research into the etiology and site specificity of MRONJ is encouraged, aiming to develop novel treatment prospects. Indeed, comprehending this would allow for increased efficacy and therapeutic options while emphasizing the importance of prevention. In addition, we advocate for greater consensus among the various societies regarding MRONJ's treatment and management.

Perspective: A multi-trait integrative approach to understanding the structural basis of bone fragility for pediatric conditions associated with abnormal bone development

Bone development is a highly orchestrated process that establishes the structural basis of bone strength during growth and functionality across the lifespan. This developmental process is generally robust in establishing mechanical function, being adaptable to many genetic and environmental factors. However, not all factors can be fully accommodated, leading to abnormal bone development and lower bone strength. This can give rise to early-onset bone fragility that negatively impacts bone strength across the lifespan. Current guidelines for assessing bone strength include measuring bone mineral density, but this does not capture the structural details responsible for whole bone strength in abnormally developing bones that would be needed to inform clinicians on how and when to treat to improve bone strength. The clinical consequence of not operationalizing how altered bone development informs decision making includes under-detection and missed opportunities for early intervention, as well as a false positive diagnosis of fragility with possible resultant clinical actions that may actually harm the growing skeleton. In this Perspective, we emphasize the need for a multi-trait, integrative approach to better understand the structural basis of bone growth for pediatric conditions with abnormal bone development. We provide evidence to showcase how this approach might reveal multiple, unique ways in which bone fragility develops across and within an array of pediatric conditions that are associated with abnormal bone development. This Perspective advocates for the development of new translational research aimed at informing better ways to optimize bone growth, prevent fragility fractures, and monitor and treat bone fragility based on the child's skeletal needs.

Radiomorphometric indices and fractal dimension of the mandible in individuals with osteogenesis imperfecta: a matched cross-sectional study

OBJECTIVE

The objective was to analyze radiomorphometric indices (RMIs) of mandibular cortical bone and fractal dimension (FD) of trabecular bone of individuals with osteogenesis imperfecta (OI) and compare the findings to those of individuals without OI.

METHODS

Digital panoramic radiographs of 20 individuals with OI (case group) and 40 individuals without OI (control group) were examined. The RMIs of mandibular cortical index (MCI) and mandibular cortical thickness (MCT) were analyzed. FD of mandibular trabecular bone was calculated bilaterally in 3 regions. The chi-squared test and paired t test were used to compare the significance of differences between the groups. The effect size and minimal clinically important difference (MCID) were also determined. Significance was established at P < .05.

RESULTS

Categories C2 and C3 of the MCI were more frequent in individuals with OI (P < .001). The Mean MCT was 2.08 ± 0.79 in the OI case group and 2.91 ± 0.60 in the control group (P < .001). Mean FD in the condylar region was significantly lower in the OI case group (P = .002). The effect size for these 2 measures was large, and the difference between groups was greater than the MCID.

CONCLUSION

Radiographs of individuals with OI exhibited more porosity and diminished thickness of the mandibular cortical bone and lower FD values in the condylar trabecular bone.

Fibrous Dysplasia of the Jaw: Advances in Imaging and Treatment

A total of 7% of all benign bone lesions are diagnosed as fibrous dysplasia (FD). The symptoms of FD of the jaw range from asymptomatic to dental anomalies, pain and facial asymmetry. Due to its resemblance to other fibro-osseous bone lesions, misdiagnosis often occurs and can lead to inadequate treatment. Particularly in the jaw, this lesion does not become quiescent during puberty, making fundamental knowledge about the diagnosis and treatment of FD crucial. Mutational analysis and nonsurgical approaches offer new diagnostic and therapeutic options. In this review, we examine the advances and the difficulties of the diagnosis and the various treatment modalities of FD of the jaw in order to capture the current scientific knowledge on this bone disease.

Fibrous Dysplasia of Temporal Bone

Fibrous dysplasia of temporal bone is a rare benign bone disease. With the advance in imaging, more cases are likely to get reported and present with less disease severity. Temporal Bone Fibrous dysplasia most commonly affects External Auditory canal resulting in External auditory canal stenosis and Conductive Hearing Loss. Many patients are asymptomatic and rarely require intervention. However, we present 3 different clinical scenarios of Temporal Bone Fibrous Dysplasia and elaborate on clinical course that lead to varied managements for each of them.

The West China Hospital radiographic classification for fibrous dysplasia in femur and adjacent bones: A retrospective analysis of 205 patients

Objective

This study aims to investigate the reliability and clinical outcome of a newly developed classification system for patients with fibrous dysplasia (FD) of the femur and adjacent bones, optimizing its evaluation and management.

Methods

A total of 205 patients (121 female and 84 male) with FD in the femur and adjacent bones were included in this retrospective study. All affected femurs were measured and treated based on this classification at our institution between 2009 and 2019. Based on previous studies and extensive clinical follow‐up, we cautiously proposed the West China Hospital radiographic classification for FD in femur and adjacent bones following corresponding treatment options. There are five types with five radiographic features, including proximal femur bone loss, coxa vara, femoral shaft deformity, genu valgum, and hip arthritis. The intraobserver and interobserver reproducibility of this classification was assessed by four observers using the Cohen kappa statistic. The clinical outcome was evaluated using the criteria of Guille.

Results

At a median follow‐up of 60 months (range 6–120), 205 patients (median 34.8 years old, range 18–73 years old) were categorized into the following five types: Type I 31.7%, Type II 30.2%, Type III 20.5%, Type IV 10.2%, and Type V 7.3%. The mean interobserver and intraobserver kappa scores were 0.85 (range 0.77–0.89) and 0.85 (range 0.79–0.92), respectively. For clinical outcomes, there was no significant difference in the postoperative Guille score for Type I patients (mean 9.01 ± 1.22). There was a significant increase in the postoperative Guille score in Type II, III, IV, and V, compared to the preoperative values (P < 0.01). For complications, two Type III patients reported pain, and one Type III patient had mild‐to‐moderate Trendelenburg gait. One Type IV patient had a mild Trendelenburg gait. And two Type V patients still had mild limping.

Conclusion

This classification is reproducible and serves as a tool for evaluating and treating FD in the femur and adjacent bones. Therefore, we recommend this classification for the diagnosis and treatment of FD‐related deformities in the femur and adjacent bones.

Vitamin D deficiency in children with cerebral palsy: A narrative review of epidemiology, contributing factors, clinical consequences and interventions

Sufficient vitamin D levels are necessary, not only for mineralization, normal growth and development of bones, but also for the prevention of fatal chronic diseases like diabetes mellitus, metabolic syndrome and cancer. This is of particular importance in children with neuro- and musculoskeletal disorders, especially cerebral palsy (CP). CP is a heterogeneous group of childhood developmental disability disorders described by uncharacteristic posture, balance, and movement. Patients with CP are at an increased risk of vitamin D deficiency and as a result reduced bone mineral density, bone fragility, osteopenia, and rickets. The present review aims to combine and summarize available evidence, regarding the epidemiology, underlying contributing factors, clinical consequences, and treatment interventions of vitamin D deficiency in children with CP.

Outcomes of Zoledronic Acid Use in Paediatric Conditions

INTRODUCTION

Limited evidence is available concerning experience with use of zoledronic acid (ZA) and treatment for conditions other than primary bone fragility.

MATERIALS AND METHODS

A retrospective review of all Royal Children Hospital patients who had been administered at least 1 dose of intravenous ZA from 2002 to 2015 was undertaken.

RESULTS

The audit included 309 children with 228 being treated for bone fragility conditions. Of the 228, 68 had height-adjusted lumbar spine bone mineral density Z-scores available over up to a 5-year period, and median increases were +2.0 SD (median absolute deviation = 0.9) (N = 36, p value for median increase of at least 0.5 in Z-score <0.001), for patients with osteogenesis imperfecta or other primary bone fragility disorders, +1.0 SD (0.9) (N = 14, p = 0.029), for immobility conditions, +0.5 SD (0.7) (N = 10, p = 0.399), and for glucocorticoid-induced secondary osteoporosis, +0.7 SD (0.6) (N = 8, p = 0.015). 81/309 children were treated for bone abnormality indications (e.g., avascular necrosis [AVN], fibrous dysplasia, and bone cysts). Of 39 with AVN, outcome data were available for 33, with joint integrity maintained for 24/33 from 6 to 24 months after last ZA, subjective reports (22/28) of reduced pain. Reduction in bone lesion size was seen in 2/4 patients with bone cysts within 12 months of ZA commencement.

DISCUSSION/CONCLUSION

This is the largest cohort of reported outcomes of ZA use in a paediatric population. Results demonstrate a good efficacy profile and associated improved bone density for osteoporotic conditions and stabilization of non-traumatic AVN with a low rate of joint collapse.

Bisphosphonate use in children with cerebral palsy

BACKGROUND

Cerebral palsy (CP) is a heterogeneous group of non-progressive disorders of posture or movement, caused by a lesion of the developing brain. Osteoporosis is common in children with cerebral palsy, particularly in children with reduced gross motor function, and leads to an increased risk of fractures. Gross motor function in children with CP can be categorised using a tool called the Gross Motor Function Classification System (GMFCS). Bisphosphonate increases bone mineral density (BMD) and reduces fracture rates. Bisphosphonate is used widely in the treatment of adult osteoporosis. However, the use of bisphosphonate in children with CP remains controversial, due to a paucity of evidence and a lack of recent trials examining the efficacy and safety of bisphosphonate use in this population.

OBJECTIVES

To examine the efficacy and safety of bisphosphonate therapy in the treatment of low BMD or secondary osteoporosis (or both) in children with cerebral palsy (GMFCS Levels III to V) who are under 18 years of age.

SEARCH METHODS

In September 2020, we searched CENTRAL, MEDLINE, Embase, six other databases, and two trial registers for relevant studies. We also searched the reference lists of relevant systematic reviews, trials, and case studies identified by the search, and contacted the authors of relevant studies in an attempt to identify unpublished literature.

SELECTION CRITERIA

All relevant randomised controlled trials (RCTs), and quasi-RCTs, comparing at least one bisphosphonate (given at any dose, orally or intravenously) with placebo or no drug, for the treatment of low BMD or osteoporosis in children up to 18 years old, with cerebral palsy (GMFCS Levels III to V).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We were unable to conduct any meta-analyses due to insufficient data, and therefore provide a narrative assessment of the results.

MAIN RESULTS

We found two relevant RCTs (34 participants). Both studies included participants with non-ambulatory CP or CP and osteoporosis. Participants in both studies were similar in severity of CP, age distribution, and sex distribution. The two trials used different bisphosphonate medications and different intervention durations, but further comparison of the interventions was not possible due to a lack of published data from one trial. One trial received funding and support from research, academic, and hospital foundations, with pharmaceutical companies providing components of the calcium and vitamin supplement; the other trial did not report sources of funding. We judged one study at an overall high risk of bias; the other as overall unclear risk of bias.

PRIMARY OUTCOME

Compared to placebo or no treatment, both studies provided very low certainty evidence of improved BMD at least four months post-intervention in children treated with bisphosphonate. Only one study (12 participants) provided sufficient detail to assess a measure of the effect, and reported an improvement at six months post-intervention in lumbar spine z-score (mean difference (MD) 18%, 95% confidence interval (CI) 6.57 to 29.43; very low certainty evidence).

SECONDARY OUTCOMES

Very low certainty evidence from one study found that bisphosphonate reduced serum N-telopeptides (NTX) more than placebo; the other study reported that both bisphosphonate plus alfacalcidol and alfacalcidol alone reduced NTX, but did not compare groups. One study reported inconclusive results between groups for serum bone-specific alkaline phosphatase (BAP). The other study reported that both bisphosphonate plus alfacalcidol and alfacalcidol alone reduced BAP, but did not compare groups. Neither study reported data for the effect of bisphosphonate treatment on changes in volumetric BMD in the distal radius or tibia, changes in fracture frequency, bone pain, or quality of life. One study reported that two participants had febrile events noted during their first dosing schedule, but no further adverse events were reported in either relevant study.

AUTHORS' CONCLUSIONS

Based on the available evidence, there is very low certainty evidence that bisphosphonate treatment may improve bone health in children with cerebral palsy. We could only include one study with 14 participants in the assessment of the effect size; therefore, the precision of the effect estimate is low. We could only evaluate one planned primary outcome, as there was insufficient detail reported in the relevant studies. Further research from RCTs on the effect and safety of bisphosphonate to improve bone health in children with cerebral palsy is required. These studies should clarify the optimal standard treatment regarding weight-bearing exercises, vitamin D and calcium supplementation, and should include fracture frequency as a primary outcome.

Clinical course in two children with Juvenile Paget's disease during long-term treatment with intravenous bisphosphonates

Juvenile Paget disease (JPD) is an ultra-rare disease, characterized by loss of function of osteoprotegerin. Osteoprotegerin inhibits osteoclast activation via the receptor activator of nuclear factor κB (RANK) pathway. Severely affected children suffer from bone deformities and pain and require long term anti-resorptive treatment. Due to the rarity of the disease, few long-term follow-up data on the clinical course in children are available.

In this report, motor development during infancy and early childhood and the activity of the bone disease based on clinical, radiographic and biochemical parameters are reported in 2 children with severe forms of JPD during long term treatment (4 and 14 years) with bisphosphonates. Results of a bone biopsy in patient 1 after 10 years of treatment and video material of the motor development of patient 2 are provided.

Doses per year of pamidronate ranged from 4 to 9 mg/kg bodyweight and were administered in 4–10 courses, yearly. Treatment was adjusted individually according to the presence of bone pain. Motor development was delayed in both children before treatment with bisphosphonates was commenced and improved thereafter. Bone histology revealed a significantly higher heterogeneity of mineralization which was mainly attributed to the increased percentage of low mineralized bone areas. Individualized intravenous treatment with pamidronate resulted in sufficient control of bone pain and suppression of bone turnover with few side effects over the observation period.

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Long-term individualized treatment with intravenous bisphosphonates in children with JPD is safe and effective to control bone turnover and pain

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Histomorphometric analyses reveal signs of high bone turnover despite long-term anti resorptive treatment.

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Without curative treatment options, severe forms of JPD are a debilitating disease with high morbidity and increased mortality

Collagen-binding peptide reverses bone loss in a mouse model of cerebral palsy based on clinical databases

BACKGROUND

Individuals with cerebral palsy (CP) experience bone loss due to impaired weight bearing. Despite serious complications, there is no standard medication.

OBJECTIVE

To develop a new pharmacological agent, we performed a series of studies. The primary aim was to develop an animal model of CP to use our target medication based on transcriptome analysis of individuals with CP. The secondary aim was to show the therapeutic capability of collagen-binding peptide (CBP) in reversing bone loss in the CP mouse model.

METHODS

A total of 119 people with CP and 13 healthy adults participated in the study and 140 mice were used for the behavioral analysis and discovery of therapeutic effects in the preclinical study. The mouse model of CP was induced by hypoxic-ischemic brain injury. Inclusion and exclusion criteria were established for CBP medication in the CP mouse model with bone loss.

RESULTS

On the basis of clinical outcomes showing insufficient mechanical loading from non-ambulatory function and that underweight mainly affects bone loss in adults with CP, we developed a mouse model of CP with bone loss. Injury severity and body weight mainly affected bone loss in the CP mouse model. Transcriptome analysis showed SPP1 expression downregulated in adults with CP who showed lower bone density than healthy controls. Therefore, a synthesized CBP was administered to the mouse model. Trabecular thickness, total collagen and bone turnover activity increased with CBP treatment as compared with the saline control. Immunohistochemistry showed increased immunoreactivity of runt-related transcription factor 2 and osteocalcin, so the CBP participated in osteoblast differentiation.

CONCLUSIONS

This study can provide a scientific basis for a promising translational approach for developing new anabolic CBP medication to treat bone loss in individuals with CP.

Measurement of Bone Mineral Density in Children with Cerebral Palsy from an Ethical Issue to a Diagnostic Necessity

Introduction

Due to concerns about cumulative radiation exposure in the pediatric population, it is not standard practice to perform dual-energy X-ray absorptiometry (DXA) analysis in the diagnostic process of musculoskeletal disorders, such as cerebral palsy (CP). This study aimed to evaluate the bone mineral density (BMD) in children with CP and the ethical justification of applying DXA analysis in these children. Material and Methods. In this monocentric retrospective analysis, data were collected from children and adolescents with CP who were treated for a primary illness for three years. A clinical examination, which included a DXA analysis, recommended by the multidisciplinary team, was performed. After applying inclusion and exclusion criteria, 60 scans remained for statistical analysis. BMD and Z-scores for the lumbar spine (LS), and hip right and left femoral neck (RFN and LFN, respectively), and total hip (TH) were recorded.

Results

The average age of children with CP when DXA analysis was first performed was about 7 years. The BMD (mean ± SD) at LS (LS-BMD) of all patients was 0.612 ± 0.12, at RFN 0.555 ± 0.11, at LFN 0.572 ± 0.1, and at TH (TH-BMD) 0.581 ± 0.13. The values of the Z-score (mean ± SD) at LS of all patients were −2.5 ± 0.22, at RFN −2.2 ± 0.21, at LFN -2.25 (SD = 0.2), and at TH -2.3 (SD = 0.23). There was no statistical significance between age and gender; however, BMI, walking ability, fracture history, and pattern of CP had a significant impact on BMD and Z-score values of these children.

Conclusion

The results of our study clearly indicate that children with CP have a higher risk of low BMD, osteoporosis, and bone fractures, which makes it ethically justifiable to perform the DXA analysis in these children.

Optimizing Nutrition and Bone Health in Children with Cerebral Palsy

Children with cerebral palsy (CP) are at risk of growth and nutrition disorders. There are numerous challenges to measure and assess growth and nutritional status in children with CP. Addressing these challenges is imperative, because the consequences of poor growth and malnutrition range from decreased bone density, muscle mass, and quality of life to impacts on intellectual quotient, behavior, attention, social participation, healthcare utilization, and health care costs. In addition to discussing approaches to assess growth and nutrition, this article examines some of the methods of optimizing nutrition and bone health, including when preparing for and recovering from surgery.

The relationship of bone mineral density and vitamin D levels with steroid use and ambulation in patients with Duchenne muscular dystrophy

Objectives

This study aims to assess the bone mineral density (BMD) and serum levels of 25(OH)-vitamin D and their relationship with steroid use and ambulation in patients with Duchenne muscular dystrophy (DMD).

Patients and methods

Between January 2017 and May 2018, medical records of a total of 67 male patients (mean age, 13.9±4.3 years; range, 8 to 25 years) who were diagnosed with definite DMD were retrospectively analyzed. Demographic data, functional activity level, steroid use, fracture history and location, serum levels vitamin D, and lumbar and hip Z-scores in BMD at the time of the initial admission were recorded.

Results

The mean level of vitamin D was 13.4±7.5 ng/mL. In terms of serum levels of vitamin D, 28 patients (41.8%) had severe deficiency, 31 (46.3%) had insufficiency, and five patients (7.5%) had deficiency. Only three (4.5%) of the patients had sufficient levels of vitamin D. The hip Z-scores were significantly lower than lumbar Z scores. There was no significant difference in the lumbar and hip BMD measurements between the patients with and without steroid use. Lumbar Z-scores were significantly lower in non-ambulatory patients than ambulatory patients.

Conclusion

It is of utmost importance to evaluate the initial serum vitamin D levels in terms of bone health and prescribe replacement in case of deficiency/insufficiency in DMD patients. Since the decrease in the BMD is evident in this patient population, maintaining the mobilization as long as possible, providing loading on the bone for a long time, may be beneficial.

Can children be affected by bisphosphonate-related osteonecrosis of the jaw? A systematic review

Knowledge of bisphosphonate-related osteonecrosis of the jaw (BRONJ) is mostly based on adult cases, however bisphosphonates are also currently recommended for different paediatric diseases resulting in osteoporosis. The aim of this study was to review the literature on the risk of developing BRONJ in children and adolescents. The PubMed, LILACS, Web of Science, Scopus, and Cochrane databases were searched using the key words "bisphosphonates", "osteonecrosis", "jaw", and "children". Literature reviews, case reports, abstracts, theses, textbooks, and book chapters were excluded. Studies involving children and young adults (younger than 24 years of age) were included. A total of 56 publications were identified. After applying the eligibility criteria, only seven articles remained. Although no cases of osteonecrosis were identified, all studies had weaknesses such as a limited sample size or the absence of risk factors for the development of osteonecrosis. There is general consensus that this subject should be of concern and that further studies should be conducted before any definitive opinion is reached. It is believed that patients with secondary osteoporosis who use bisphosphonates continuously should be followed up during adulthood, since bone turnover decreases over the years.

Calcium intake improvement after nutritional intervention in paediatric patients with osteogenesis imperfecta

BACKGROUND

In several bone disorders, adequate calcium intake is a coadjuvant intervention to regular treatment. Osteogenesis imperfecta (OI) is a collagen disorder with a range of symptoms, ranging from fractures to minimum trauma, and it is typically treated with bisphosphonates. In the present study, we evaluate the impact of a nutritional intervention (NI) on dietary calcium intake and bone mineral density (BMD) in paediatric patients with OI.

METHODS

A nonrandomised clinical trial was designed with a NI. Dietary calcium intake, anthropometry and clinical features were assessed at baseline, including anthropometry, basal metabolic rate (BMR), BMD. In addition, a food guidance form was developed and sent to patients by mail. After 12 months, clinical features of patients were reassessed and compared with the baseline data.

RESULTS

Fifty-two children and adolescents were enrolled. Significant increases in total calcium intake (mg day^-1 ), percentage of adequate calcium intake (%) and number of cups of milk ingested were observed after NI. We detected a positive correlation between the variation of BMD and milk consumption in patients treated with bisphosphonate.

CONCLUSIONS

We observed an increase in calcium intake in patients with OI. This finding demonstrates the importance of nutrition therapy as part of a multidisciplinary treatment approach for bone health.

Outcomes following intravenous bisphosphonate infusion in pediatric patients: A 7-year retrospective chart review

INTRODUCTION

Intravenous bisphosphonates (IV BP) have been used to treat children with osteoporosis for many years. Favorable side effect profile and improvements in bone mineral density (BMD) have been demonstrated in patients with osteogenesis imperfecta (OI), a primary form of osteoporosis in pediatrics. Less is known about the safety of IV BP in children with secondary osteoporosis or glucocorticoid-induced osteoporosis (GIO). We aimed to determine the prevalence of both acute and long-term side effects and assess the efficacy of IV BP treatment to increase bone mineral density in pediatric patients with varying presentations of compromised bone health.

METHODS

We conducted a retrospective chart review of pediatric patients (<21 years old) treated for osteoporosis with intravenous pamidronate (PAM) or zoledronic acid (ZA) at Cincinnati Children's Hospital Medical Center from 2010 to 2017. Patient demographics, diagnosis, infusion type and dose, acute phase reactions (APR), electrolyte abnormalities, and bone density measurements were collected from the electronic medical records. Diagnoses were grouped into 3 categories: primary osteoporosis, secondary osteoporosis, and GIO. Descriptive characteristics and adverse events were compared among categories. Change in bone mineral density (BMD) over time was compared among groups.

RESULTS

123 patients (56% male) received 942 infusions (83% PAM and 17% ZA). APR was reported in 7% of all infusions and more common in secondary osteoporosis (16%, p < 0.0001). There was a higher percentage of acute adverse events after the first infusion (27% vs 5%, p < 0.0001). Hypocalcemia following IV BP infusions occurred in 7% (27/379) of infusions and was significantly associated with ZA use (p = 0.04). Severity of hypocalcemia was generally mild, requiring intravenous calcium in 3% (13/379) of infusions. Hypophosphatemia occurred frequently, however rarely required intravenous supplementation. In 468 patient years of IV BP exposure, there were no reports of osteonecrosis of the jaw (ONJ) nor atypical femoral fracture (AFF). Lumbar spine (LS) aBMD Z-score 1 year after IV BP initiation increased overall for all groups (p < 0.0001) but did not significantly differ for those who did or did not fracture following IV BP treatment.

CONCLUSIONS

APR due to intravenous BP treatment for pediatric osteoporosis were infrequent and generally mild. APR were more likely to occur in patients with secondary osteoporosis, a group who may require closer monitoring. A higher proportion of hypophosphatemia occurred in the patients with GIO. Long-term serious adverse events including ONJ and AFF were not identified in our patient population. LS aBMD Z-score increased following initiation of IV BP. However, the change in BMD was not associated with risk of fracture during the follow-up interval. These data provide reassurance and suggest that IV BP can be safely used in pediatric patients with osteoporosis.

Low Dose of Bisphosphonate Enhances Sclerostin Antibody-Induced Trabecular Bone Mass Gains in Brtl/+ Osteogenesis Imperfecta Mouse Model

Osteogenesis imperfecta (OI) is a genetic disorder characterized by altered bone quality and imbalanced bone remodeling, leading to skeletal fractures that are most prominent during childhood. Treatments for OI have focused on restoring pediatric bone density and architecture to recover functional strength and consequently reduce fragility. Though antiresorptive agents like bisphosphonates (BPs) are currently the most common intervention for the treatment of OI, a number of studies have shown efficacy of sclerostin antibody (SclAb) in inducing gains in bone mass and reducing fragility in OI mouse models. In this study, the effects of the concurrent use of BP and SclAb were evaluated during bone growth in a mouse harboring an OI-causing Gly→Cys mutation on col1a1. A single dose of antiresorptive BP facilitated the anabolic action of SclAb by increasing availability of surfaces for new bone formation via retention of primary trabeculae that would otherwise be remodeled. Chronic effects of concurrent administration of BP and SclAb revealed that accumulating cycles conferred synergistic gains in trabecular mass and vertebral stiffness, suggesting a distinct advantage of both therapies combined. Cortical gains in mass and strength occurred through SclAb alone, independent of presence of BP. In conclusion, these preclinical results support the scientific hypothesis that minimal antiresorptive treatment can amplify the effects of SclAb during early stages of skeletal growth to further improve bone structure and rigidity, a beneficial outcome for children with OI. © 2018 American Society for Bone and Mineral Research.

Zoledronic acid prevents disuse osteopenia and augments gene expression of osteoclastic differentiation markers in mice

OBJECTIVES

Disuse is characterized by a rapid and profound bone resorption. Zoledronic acid (Zol) inhibits osteoclastic bone resorption. The aim of the study was to prevent disuse osteopenia with Zol and investigate gene expression markers of osteoclastic differentiation.

METHODS

Disuse osteopenia was induced by injecting botulinum toxin (BTX) into the right hind limb of 16-week-old C57BL/6J female mice. Zol (100 µg/kg) was injected s.c. once at study start. The immobilized bones were investigated with DEXA, microCT, mechanical testing, dynamic bone histomorphometry, and RT-qPCR.

RESULTS

The BTX-injections resulted in a loss of cortical and trabecular bone as well as mechanical strength compared to intact baseline and control mice. Treatment with Zol prevented the loss of bone and mechanical strength. Interestingly, treatment with Zol resulted in a higher expression of Nfatc1 and Dcstamp, which are markers osteoclastic differentiation.

CONCLUSIONS

Zol effectively prevented BTX-induced disuse osteopenia. Furthermore, gene expression markers of osteoclastic differentiation were increased in Zol treated immobilized mice, indicating that Zol only affect mature bone resorbing osteoclasts in vivo. However, the current findings are preliminary and calls for further studies.

Sclerostin Antibody Augments the Anabolic Bone Formation Response in a Mouse Model of Mechanical Tibial Loading

Decreased activity or expression of sclerostin, an endogenous inhibitor of Wnt/β-catenin signaling, results in increased bone formation and mass. Antibodies targeting and neutralizing sclerostin (Scl-Ab) have been shown to increase bone mass and reduce fracture risk. Sclerostin is also important in modulating the response of bone to changes in its biomechanical environment. However, the effects of Scl-Ab on mechanotransduction are unclear, and it was speculated that the loading response may be altered for individuals receiving Scl-Ab therapy. To address this, we carried out a 2-week study of tibial cyclic compressive loading on C57Bl/6 mice treated with vehicle or 100 mg/kg/wk Scl-Ab. Increases in bone volume, density, and dynamic bone formation were found with loading, and the anabolic response was further increased by the combination of load and Scl-Ab. To investigate the underlying mechanism, gene profiling by RNA sequencing (RNAseq) was performed on tibias isolated from mice from all four experimental groups. Major alterations in Wnt/β-catenin gene expression were found with tibial loading, however not with Scl-Ab treatment alone. Notably, the combination of load and Scl-Ab elicited a synergistic response from a number of specific Wnt-related and mechanotransduction factors. An unexpected finding was significant upregulation of factors in the Rho GTPase signaling pathway with combination treatment. In summary, combination therapy had a more profound anabolic response than either Scl-Ab or loading treatment alone. The Wnt/β-catenin and Rho GTPase pathways were implicated within bone mechanotransduction and support the concept that bone mechanotransduction is likely to encompass a number of interconnected signaling pathways. © 2017 American Society for Bone and Mineral Research.

Different clinical presentation and management of temporal bone fibrous dysplasia in children

Background

Fibrous dysplasia is a slowly progressive benign fibro-osseous disorder that involves one or multiple bones with a unilateral distribution in most cases. It is a lesion of unknown etiology, uncertain pathogenesis, and diverse histopathology. Temporal bone involvement is the least frequently reported type, especially in children.

We reviewed available articles regarding fibrous dysplasia with temporal bone involvement in children and added four patients aged 7 to 17 years who were diagnosed and treated in our institution from 2006 to 2017. The patients’ clinical picture comprised head deformity, external canal stenosis, headache, progressive conductive and/or sensorineural hearing loss, tinnitus, and sudden deafness. Two patients had experienced severe episodic vertigo with nausea and vomiting. Two were referred to us with external canal obstruction and secondary cholesteatoma formation with broad middle ear destruction. One was diagnosed with acute mastoiditis and intracranial complications. Optimal management of fibrous dysplasia is unclear and can be challenging, especially in children. In our two patients with disease expansion and involvement of important structures, surgical treatment was abandoned and a “wait-and-scan” policy was applied. The other two were qualified for surgical treatment. One patient underwent two surgeries: modified lateral petrosectomy (canal left open) with pathological tissue removal, cavity obliteration, and subsequent tympanoplasty. Another patient with extensive destruction of the left temporal bone underwent canal wall down mastoidectomy with perisinus abscess drainage and revision 12 months later. Tympanoplasty was unsatisfactory in both patients because of slow progression of the middle ear pathology. None of our patients underwent pharmacological treatment.

Conclusions

In younger patients, observation and a “wait-and-scan” protocol is relevant until significant function, or cosmetic deficits are obvious. Surgery is not preferred and should be delayed until puberty because fibrous dysplasia has a tendency to stabilize after adolescence. In patients with severe symptoms medical treatment can be implemented, but safety of this treatment in children remain controversial.

Local vs. systemic administration of bisphosphonates in rat cleft bone graft: A comparative study

A majority of patients with orofacial cleft deformity requires cleft repair through a bone graft. However, elevated amount of bone resorption and subsequent bone graft failure remains a significant clinical challenge. Bisphosphonates (BPs), a class of anti-resorptive drugs, may offer great promise in enhancing the clinical success of bone grafting. In this study, we compared the effects of systemic and local delivery of BPs in an intraoral bone graft model in rats. We randomly divided 34 female 20-week-old Fischer F344 Inbred rats into four groups to repair an intraoral critical-sized defect (CSD): (1) Control: CSD without graft (n = 4); (2) Graft/Saline: bone graft with systemic administration of saline 1 week post-operatively (n = 10); (3) Graft/Systemic: bone graft with systemic administration of zoledronic acid 1 week post-operatively (n = 10); and (4) Graft/Local: bone graft pre-treated with zoledronic acid (n = 10). At 6-weeks post-operatively, microCT volumetric analysis showed a significant increase in bone fraction volume (BV/TV) in the Graft/Systemic (62.99 ±14.31%) and Graft/Local (69.35 ±13.18%) groups compared to the Graft/Saline (39.18±10.18%). Similarly, histological analysis demonstrated a significant increase in bone volume in the Graft/Systemic (78.76 ±18.00%) and Graft/Local (89.95 ±4.93%) groups compared to the Graft/Saline (19.74±18.89%). The local delivery approach resulted in the clinical success of bone grafts, with reduced graft resorption and enhanced osteogenesis and bony integration with defect margins while avoiding the effects of BPs on peripheral osteoclastic function. In addition, local delivery of BPs may be superior to systemic delivery with its ease of procedure as it involves simple soaking of bone graft materials in BP solution prior to graft placement into the defect. This new approach may provide convenient and promising clinical applications towards effectively managing cleft patients.

Lower incidence of fracture after IV bisphosphonates in girls with Rett syndrome and severe bone fragility

BACKGROUND

Classic Rett Syndrome (RS) is a disabling condition mainly caused by MECP2 mutations. Girls with RS are at risk of developing bone fragility and fractures at a young age which results in pain and may seriously impair quality of life.

OBJECTIVE

To retrospectively assess the safety and efficacy of IV bisphosphonates on fracture, bone mineral density (BMD) and bone markers in RS girls with bone fragility.

METHODS

RS girls received either IV pamidronate (n = 19) or IV zoledronate (n = 1) for 2 years.

RESULTS

Of 20 patients studied (age: 12.5 years [6; 39]), 14 were non-ambulatory. The incidence of fracture decreased from 37 fractures in 20 patients, to 1 fracture during or after treatment (follow-up: 3.1 years [1.5; 5]). The spine BMD Z-score improved from -3.2 [-5.6; -0.1] to -2.2 [-3.8; 0.0], p = 0.0006. Most parents reported decreases in chronic pain and 2 patients started to walk. Urinary calcium excretion decreased from 0.7 [0.18; 1.5] to 0.2 [0.03; 0.67] mM/mM of creatinine (p = 0.0001). Pamidronate was well tolerated.

CONCLUSION

RS girls should be screened for impaired bone mineralization and preventive measures should be taken. In girls experiencing fractures, IV bisphosphonates constitute a beneficial adjuvant treatment to diminish the risk of fracture and restore bone density.

Bisphosphonate use in children with cerebral palsy

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To examine the efficacy and safety of bisphosphonate therapy in the treatment of low BMD or secondary osteoporosis (or both) in children with cerebral palsy (GMFCS Levels III to V) who are under 18 years of age.

Evaluation of the effectiveness of robotic gait training and gait-focused physical therapy programs for children and youth with cerebral palsy: a mixed methods RCT

Background

Robot assisted gait training (RAGT) is considered to be a promising approach for improving gait-related gross motor function of children and youth with cerebral palsy. However, RAGT has yet to be empirically demonstrated to be effective. This knowledge gap is particularly salient given the strong interest in this intensive therapy, the high cost of the technology, and the requirement for specialized rehabilitation centre resources.

Methods

This is a research protocol describing a prospective, multi-centre, concurrent mixed methods study comprised of a randomized controlled trial (RCT) and an interpretive descriptive qualitative design. It is a mixed methods study designed to determine the relative effectiveness of three physical therapy treatment conditions (i.e., RAGT, a functional physical therapy program conducted over-ground (fPT), and RAGT + fPT) on gait related motor skills of ambulatory children with cerebral palsy. Children with cerebral palsy aged 5–18 years who are ambulatory (Gross Motor Function Classification System Levels II and III) will be randomly allocated to one of four treatment conditions: 1) RAGT, 2) fPT, 3) RAGT and fPT combined, or 4) a maintenance therapy only control group. The qualitative component will explicate child and parent experiences with the interventions, provide insight into the values that underlie their therapy goals, and assist with interpretation of the results of the RCT.

Discussion

n/a.

Trial Registration

NCT02391324 Registered March 12, 2015.

Are Changes in Composition in Response to Treatment of a Mouse Model of Osteogenesis Imperfecta Sex-dependent?

BACKGROUND

Osteogenesis imperfecta (OI) is a genetic disease characterized by skeletal fragility and deformity. There is extensive debate regarding treatment options in adults with OI. Antiresorptive treatment reduces the number of fractures in growing oim/oim mice, an animal model that reproducibly mimics the moderate-to-severe form of OI in humans. Effects of long-term treatments with antiresorptive agents, considered for treatment of older patients with OI with similar presentation (moderate-to-severe OI) are, to date, unknown.

QUESTIONS/PURPOSES

Fourier transform infrared (FTIR) imaging, which produces a map of the spatial variation in chemical composition in thin sections of bone, was used to address the following questions: (1) do oim/oim mice show a sex dependence in compositional properties at 6.5 months of age; (2) is there a sex-dependent response to treatment with antiresorptive agents used in the treatment of OI in humans; and (3) are any compositional parameters in oim/oim mice corrected to wild-type (WT) values after treatment?

METHODS

FTIR imaging data were collected from femurs from four to five mice per sex per genotype per treatment. Treatments were 24 weeks of saline, alendronate, or RANK-Fc; and 12 weeks of saline+12 weeks RANK-Fc and 12 weeks of alendronate+RANK-Fc. FTIR imaging compositional parameters measured in cortical and cancellous bones were mineral-to-matrix ratio, carbonate-to-mineral ratio, crystal size/perfection, acid phosphate substitution, collagen maturity, and their respective distributions (heterogeneities). Because of the small sample size, nonparametric statistics (Mann-Whitney U- and Kruskal-Wallis tests with Bonferroni correction) were used to compare saline-treated male and female mice of different genotypes and treatment effects by sex and genotype, respectively. Statistical significance was defined as p<0.05.

RESULTS

At 6.5 months, saline-treated male cortical oim/oim bone had increased mineral-to-matrix ratio (p=0.016), increased acid phosphate substitution (p=0.032), and decreased carbonate-to-mineral ratio (p=0.016) relative to WT. Cancellous bone in male oim/oim also had increased mineral-to-matrix ratio (p=0.016) relative to male WT. Female oim/oim mouse bone composition for all cortical and cancellous bone parameters was comparable to WT (p>0.05). Only the female WT mice showed a response of mean compositional properties to treatment, increasing mineral-to-matrix after RANK-Fc treatment in cancellous bone (p=0.036) compared with saline-treated mice. Male oim/oim increased mineral-to-matrix cortical and cancellous bone heterogeneity in response to all long-term treatments except for saline+RANK-Fc (p<0.04); female oim/oim cortical mineral-to-matrix bone heterogeneity increased with ALN+RANK-Fc and all treatments increased cancellous female oim/oim bone acid phosphate substitution heterogeneity (p<0.04).

CONCLUSIONS

Both oim/oim and WT mice, which demonstrate sex-dependent differences in composition with saline treatment, showed few responses to long-term treatment with antiresorptive agents. Female WT mice appeared to be more responsive; male oim/oim mice showed more changes in compositional heterogeneity. Changes in bone composition caused by these agents may contribute to improved bone quality in oim/oim mice, because the treatments are known to reduce fracture incidence.

CLINICAL RELEVANCE

The optimal drug therapy for long-term treatment of patients with moderate-to-severe OI is unknown. Based on bone compositional changes in mice, antiresorptive treatments are useful for continued treatment in OI. There is a reported sexual dimorphism in fracture incidence in adults with OI, but to date, no one has reported differences in response to pharmaceutical intervention. This study suggests that such an investigation is warranted.

An update on childhood bone health: mineral accrual, assessment and treatment

PURPOSE OF REVIEW

To update the reader's knowledge about the factors that influence bone mineral accrual and to review the advances in the assessment of bone health and treatment of bone disorders.

RECENT FINDINGS

Maternal vitamin D status influences neonatal calcium levels, bone mineral density (BMD) and bone size. In turn, BMD z-score tends to track in childhood. These factors highlight the importance of bone health as early as fetal life. Dual-energy x-ray absorptiometry is the mainstay of clinical bone health assessment in this population because of the availability of appropriate reference data. Recently, more information has become available about the assessment and treatment of bone disease in chronically ill pediatric patients.

SUMMARY

Bone health must become a health focus starting prenatally in order to maximize peak bone mass and to prevent osteoporosis-related bone disease in adulthood. Vitamin D, calcium and weight-bearing activity are the factors of key importance throughout childhood in achieving optimal bone health as BMD z-score tracks through childhood and into adulthood. Recent updates of the International Society for Clinical Densitometry focus on the appropriate use of dual-energy x-ray absorptiometry in children of all ages, including children with chronic disease, and on the treatment of pediatric bone disease.

Patterns of bisphosphonates utilization in patients under age 45 in a large cohort of commercial insurance beneficiaries in the United States

Background

The effectiveness and safety of bisphosphonates treatment used in the young population have not been well studied. Despite insufficient data on effectiveness and safety of bisphosphonates in young patients, bisphosphonates are still considered in younger patients at high risk for osteoporosis or fracture. The objectives of this study were to identify bisphosphonate initiators aged 10–45 years and describe their clinical characteristics and to assess time trends of bisphosphonate use over the past decade in a large U.S. population-based cohort.

Methods

Using the medical and pharmacy claims data from a U.S. commercial insurance (2003–2012), patients aged 10–45 years without malignancy who initiated an oral or intravenous bisphosphonate after at least 1 year of insurance enrollment were selected. Baseline demographics, comorbidities, medications and health care utilization were assessed in the year prior to initiating a bisphosphonate. The trend of bisphosphonate use over time was examined.

Results

There were 9,082 bisphosphonate initiators (0.02% of the same age group in the population). The mean age was 38.1 years and 79.6% female. Osteoporosis was the most common diagnosis (41.2%). At baseline, 10.8% had a diagnosis of fracture and 29.0% had a bone mineral density measured. Of those who used glucocorticoids (39%) at baseline, the mean 1-year cumulative prednisone-equivalent dose was 2,669 milligrams. The use of bisphosphonates in the young population significantly decreased over the past decade (p<0.001).

Conclusions

Among young patients aged 10–45, the use of bisphosphonates was uncommon and significantly decreased over the past decade in the U.S. While most patients initiating bisphosphonates had a diagnosis of osteoporosis and fracture in the preceding year, some had no recorded claims with a diagnosis of fracture, osteoporosis, or long-term glucocorticoids use at baseline. Future research is needed to examine the effectiveness and safety of bisphosphonates in young patients at risk for osteoporosis.