The contribution of cortical and trabecular tissues to bone strength: insights from denosumab studies

Bioactive Materials for Bone Regeneration: Biomolecules and Delivery Systems

Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been documented with novel strategies currently under investigation. Innovative biomaterials that allow the coordinated and well-controlled repair of bone fractures and bone loss are being designed to reduce the need for autologous or allogeneic bone grafts eventually. The current engineering technologies permit the construction of synthetic, complex, biomimetic biomaterials with properties nearly as good as those of natural bone with good biocompatibility. To ensure that all these requirements meet, bioactive molecules are coupled to structural scaffolding constituents to form a final product with the desired physical, chemical, and biological properties. Bioactive molecules that have been used to promote bone regeneration include protein growth factors, peptides, amino acids, hormones, lipids, and flavonoids. Various strategies have been adapted to investigate the coupling of bioactive molecules with scaffolding materials to sustain activity and allow controlled release. The current manuscript is a thorough survey of the strategies that have been exploited for the delivery of biomolecules for bone regeneration purposes, from choosing the bioactive molecule to selecting the optimal strategy to synthesize the scaffold and assessing the advantages and disadvantages of various delivery strategies.

Bone fragility: conceptual framework, therapeutic implications, and COVID-19-related issues

Bone fragility is the susceptibility to fracture even for common loads because of structural, architectural, or material alterations of bone tissue that result in poor bone strength. In osteoporosis, quantitative and qualitative changes in density, geometry, and micro-architecture modify the internal stress state predisposing to fragility fractures. Bone fragility substantially depends on the structural behavior related to the size and shape of the bone characterized by different responses in the load–deformation curve and on the material behavior that reflects the intrinsic material properties of the bone itself, such as yield and fatigue. From a clinical perspective, the measurement of bone density by DXA remains the gold standard for defining the risk of fragility fracture in all population groups. However, non-quantitative parameters, such as macro-architecture, geometry, tissue material properties, and microcracks accumulation can modify the bone’s mechanical strength. This review provides an overview of the role of different contributors to bone fragility and how these factors might be influenced by the use of anti-osteoporotic drugs and by the COVID-19 pandemic.

Peripheral quantitative computed tomography (pQCT) measures are associated with prior low trauma fracture in men

Peripheral quantitative computed tomography (pQCT) assesses bone quantity and quality, complementary to current standard practice, and has potential to improve prediction of fracture risk. This study explored whether pQCT parameters were associated with prior fracture in men and found a number of parameters to be associated, particularly at the radius.

PURPOSE

Peripheral quantitative computed tomography (pQCT) provides information about bone structure and density complementary to dual x-ray absorptiometry. This study aimed to determine which pQCT parameters are associated with prior fracture.

METHODS

Participants were men (n = 508, age 33-96 years) from the Geelong Osteoporosis Study. Parameters at 4% (n = 469) and 66% (n = 436) of radial length, and 4% (n = 449) and 66% (n = 437) of tibial length were acquired (pQCT XCT 2000, Stratec Medizintechnik, Pforzheim, Germany), and mean standardised. Low trauma prior fractures in adulthood (≥ age 20 years) were radiologically confirmed when possible. Cross-sectional associations between pQCT and fracture were tested using logistic regression adjusting for confounders.

RESULTS

Prior low trauma fractures were identified for 106 participants. Fracture was negatively associated with parameters at the 4% radius site: bone mass (adjusted OR = 0.67; 95%CI = 0.52-0.86), total density (OR = 0.61; 95%CI = 0.47-0.78), trabecular density (OR = 0.62; 95%CI = 0.48-0.79) and cortical subdensity (OR = 0.61; 95%CI = 0.47-0.77). At the 66% radius site, fracture was associated with total density (OR = 0.69; 95%CI = 0.55-0.87) and cortical thickness (OR = 0.68; 95%CI = 0.54-0.86). Fracture was associated with the ratio of the cortical area at the 66% site to the total area at the 4% site (OR = 0.74; 95%CI = 0.58-0.94). Prior fracture was negatively associated with parameters at the 4% tibial site: total density (OR = 0.67; 95%CI = 0.52-0.86), trabecular density (OR = 0.64; 95%CI = 0.50-0.82) and cortical subdensity (OR = 0.72; 95%CI = 0.56-0.92). Fracture was negatively associated with cortical density at the 66% site (OR = 0.74; 95%CI = 0.58-0.94), and the ratio of the cortical area at the 66% site to the total area at the 4% site (OR = 0.65; 95%CI = 0.46-0.91), but were attenuated in adjusted models. No other associations were identified.

CONCLUSION

Prior fracture was associated with parameters at both the radius and tibia. This study highlights key pQCT parameters that may aid in the prediction of fracture risk.

Elevated parathyroid hormone levels in older women treated for osteoporosis using denosumab

PURPOSE

Primary care physicians (PCPs) often struggle with elevated serum intact parathyroid hormone (iPTH) in osteoporotic patients on antiresorptive treatment, specifically, denosumab. As iPTH and calcium levels need to be within normal ranges to receive the next dose of denosumab, continuously high serum iPTH may necessitate additional tests to rule out pathological causes. We aimed to determine factors associated with iPTH elevation in a cohort of postmenopausal women receiving osteoporosis treatment.

METHOD

A cross-sectional analysis of electronic medical records of patients 50 years and older who visited a geriatric osteoporosis clinic between October 1, 2014 and December 31, 2019, was conducted. We divided patients into 3 categories: not currently on treatment, on bisphosphonates or on denosumab. Percentage change in iPTH levels from baseline to 1 year follow-up was the outcome measure. Other variables used are age, body mass index, chronic co-morbidities, 25OH-vitamin D, calcium, TSH, glomerular filtration rate and femoral neck BMD. Linear regression models were used to assess independent associations between treatment group and iPTH changes.

RESULTS

Mean (SD) age of 173 participants in our study was 78 (± 10) years, and 71% were Caucasian. At follow-up, mean percent change of iPTH was 13.47 ± 62.76, 30.35 ± 61.17, and 39.60 ± 35.51 in the "no treatment", "bisphosphonate" and "denosumab" groups, respectively. Age was a predictor of elevated percent change of iPTH in the denosumab group.

CONCLUSION

Increasing age is associated with iPTH elevations in osteoporotic patients on denosumab. In the absence of any pathology, continuation of denosumab may be safe in lowering fracture risk. However, a larger study may be required to confirm this.

IL-23 receptor deficiency results in lower bone mass via indirect regulation of bone formation

The IL-23 receptor (IL-23R) signaling pathway has pleiotropic effects on the differentiation of osteoclasts and osteoblasts, since it can inhibit or stimulate these processes via different pathways. However, the potential role of this pathway in the regulation of bone homeostasis remains elusive. Therefore, we studied the role of IL-23R signaling in physiological bone remodeling using IL-23R deficient mice. Using µCT, we demonstrate that 7-week-old IL-23R^−/− mice have similar bone mass as age matched littermate control mice. In contrast, 12-week-old IL-23R^−/− mice have significantly lower trabecular and cortical bone mass, shorter femurs and more fragile bones. At the age of 26 weeks, there were no differences in trabecular bone mass and femur length, but most of cortical bone mass parameters remain significantly lower in IL-23R^−/− mice. In vitro osteoclast differentiation and resorption capacity of 7- and 12-week-old IL-23R^−/− mice are similar to WT. However, serum levels of the bone formation marker, PINP, are significantly lower in 12-week-old IL-23R^−/− mice, but similar to WT at 7 and 26 weeks. Interestingly, Il23r gene expression was not detected in in vitro cultured osteoblasts, suggesting an indirect effect of IL-23R. In conclusion, IL-23R deficiency results in temporal and long-term changes in bone growth via regulation of bone formation.

Analysis of the subsequent treatment of osteoporosis by transitioning from bisphosphonates to denosumab, using quantitative computed tomography: A prospective cohort study

Purpose

Denosumab reduces bone resorption and improves bone mineral density (BMD). Studies have analyzed subsequent treatment transitioning from bisphosphonates to denosumab based on dual-energy X-ray absorptiometry scanning (DXA). Quantitative computed tomography (QCT) can help assess cortical and trabecular bones separately in three dimensions without the interference of the surrounding osteophytes. In the present study, we analyzed the subsequent treatment transition from bisphosphonates to denosumab using QCT.

Methods

Thirty-two patients with postmenopausal osteoporosis to be treated with denosumab were recruited. The patients were divided into two groups (15 prior bisphosphonate and 17 naïve) based on their previous treatment. BMD of the lumbar spine and hip were evaluated by DXA and QCT at baseline and 12 months following denosumab treatment.

Results

The percentage change in volumetric BMD assessed by QCT at 12 months significantly improved in the naïve group compared with that in the prior bisphosphonate group. The region-specific assessment of femur at 12 months revealed that denosumab treatment was effective in both cortical and trabecular bones except the trabecular region of the prior bisphosphonate group.

Conclusion

Our study suggests that although denosumab treatment was useful in both treatment groups, BMD increase was significantly higher in the naïve group than in the prior-bisphosphonate group. Interestingly, in the prior-bisphosphonate group, denosumab treatment was more effective in the cortical region than the trabecular region. Our study offers insights into the subsequent treatment and permits greater confidence when switching to denosumab from bisphosphonates.

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We analyzed the treatment transition from bisphosphonates to denosumab using QCT.

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Percentage change in volumetric BMD at 12 months significantly improved in the naïve group.

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Denosumab treatment was more effective on the cortical region than the trabecular region.

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Our study offers insights into the subsequent treatment when switching to denosumab.

Biomechanical Properties of Metastatically Involved Osteolytic Bone

PURPOSE OF REVIEW

Skeletal metastasis involves the uncoupling of physiologic bone remodeling resulting in abnormal bone turnover and radical changes in bony architecture, density, and quality. Bone strength assessment and fracture risk prediction are critical in clinical treatment decision-making. This review focuses on bone tissue and structural mechanisms altered by osteolytic metastasis and the resulting changes to its material and mechanical behavior.

RECENT FINDINGS

Both organic and mineral phases of bone tissue are altered by osteolytic metastatic disease, with diminished bone quality evident at multiple length-scales. The mechanical performance of bone with osteolytic lesions is influenced by a combination of tissue-level and structural changes. This review considers the effects of osteolytic metastasis on bone biomechanics demonstrating its negative impact at tissue and structural levels. Future studies need to assess the cumulative impact of cancer treatments on metastatically involved bone quality, and its utility in directing multimodal treatment planning.

Pharmacological Therapy of Osteoporosis: What's New?

Osteoporosis and fragility fractures are relevant health issues because of their impact in terms of morbidity, mortality, and socioeconomic burden. Despite this alarming scenario, both underdiagnosis and undertreatment are common features of osteoporotic patients, particularly those who have already sustained a fragility fracture. Pharmacotherapy of osteoporosis is the main treatment option for these patients because of strong evidence about the efficacy of available drugs targeting bone metabolism. However, several issues can interfere with the effectiveness of anti-osteoporotic drugs in clinical practice, such as lack of awareness of both healthcare providers and patients, poor adherence to therapy, and safety in long-term treatment. Therefore, new therapeutic strategies have been proposed to overcome these problems, such as sequential therapy or emerging molecules mainly targeting the stimulation of bone formation. In particular, abaloparatide has been demonstrated to reduce major nonvertebral fracture risk compared with both placebo and teriparatide, although the European Medicines Agency (EMA) refused the marketing authorization because the benefits of this drug did not outweigh its risks. On the other side, EMA has recently approved romosozumab, a monoclonal antibody directed against sclerostin and the only available therapeutic option targeting Wnt signaling, as both bone-forming and antiresorptive intervention to treat osteoporosis and fragility fractures.

Differential Modulation of Cancellous and Cortical Distal Femur by Fructose and Natural Mineral-Rich Water Consumption in Ovariectomized Female Sprague Dawley Rats

Bone mineral density (BMD) and microstructure depend on estrogens and diet. We assessed the impact of natural mineral-rich water ingestion on distal femur of fructose-fed estrogen-deficient female Sprague Dawley rats. Ovariectomized rats drank tap or mineral-rich waters, with or without 10%-fructose, for 10 weeks. A sham-operated group drinking tap water was included (n = 6/group). Cancellous and cortical bone compartments were analyzed by microcomputed tomography. Circulating bone metabolism markers were measured by enzyme immunoassay/enzyme-linked immunosorbent assay or multiplex bead assay. Ovariectomy significantly worsened cancellous but not cortical bone, significantly increased circulating degradation products from C-terminal telopeptides of type I collagen and receptor activator of nuclear factor-kappaB ligand (RANKL), and significantly decreased circulating osteoprotegerin and osteoprotegerin/RANKL ratio. In ovariectomized rats, in cancellous bone, significant water effect was observed for all microstructural properties, except for the degree of anisotropy, and BMD (neither a significant fructose effect nor a significant interaction between water and fructose ingestion effects were observed). In cortical bone, it was observed a significant (a) water effect for medullary volume and cortical endosteal perimeter; (b) fructose effect for cortical thickness, medullary volume, cross-sectional thickness and cortical endosteal and periosteal perimeters; and (c) interaction effect for mean eccentricity. In blood, significant fructose and interaction effects were found for osteoprotegerin (no significant water effect was seen). For the first time in ovariectomized rats, the positive modulation of cortical but not of cancellous bone by fructose ingestion and of both bone locations by natural mineral-rich water ingestion is described.

Analysis of anti-osteoporosis function of chlorogenic acid by gene microarray profiling in ovariectomy rat model

The aim of the present study was to clarify the effect of chlorogenic acid (CGA) on estrogen deficiency-induced osteoporosis based on micro-computed tomography (micro-CT) and potential mechanism of gene regulation via microarray profiling. Eighteen female Sprague–Dawley rats were divided randomly into sham-operated group, ovariectomy (OVX) plus saline vehicle group, and OVX plus CGA treatment group (CGA at 45 mg/kg/day). The loss of bone mass of the femoral metaphysis was evaluated by micro-CT to represent. Gene expression profiling was analyzed for bone marrow mesenchymal stem cells (BMSCs) of OVX and OVXT groups. Bioinformatics analysis was used to find the potential pathways regulated by CGA. OVX-induced osteoporosis could decrease femur bone mineral density (BMD), bone volume/tissue volume (BV/TV), trabecula number (Tb.N), and trabecular thickness (Tb.Th) and increased the trabecular separation (Tb.Sp) and structure model index (SMI) in the rats. Gene microarray profiling showed 121 differentially expressed genes in collected BMSCs between OVX and OVXT groups were identified with a threshold of a two-fold change and P<0.05. Kyoto Encyclopedia of Genes and Genomes (KEGG) was used to analyze the potential mechanism of CGA and we observed that many mitogen-activated protein kinase (MAPK) pathway associtated genes were altered, suggesting this pathway may play an important role. CGA improved bone quality by modifying the BMD and trabecular microarchitecture. Differential expression genes were screened by gene microarray profile and the results suggested MAPK pathway might participate in the process of OVX-induced bone remodeling.

Is osteoporosis an autoimmune mediated disorder?

The last two decades have marked a growing understanding of the interaction occurring between bone and immune cells. The chronic inflammation and immune system dysfunction commonly observed to occur during the ageing process and as part of a range of other pathological conditions, commonly associated with osteoporosis has led to the recognition of these processes as important determinants of bone disease. This is further supported by the recognition that the immune and bone systems in fact share regulatory mechanisms and progenitor molecules. Research into this complex synergy has provided a better understanding of the immunopathogenesis underlying bone diseases such as osteoporosis. However, existing research has largely focussed on delineating the role played by inflammation in pathogenic bone destruction, despite increasing evidence implicating autoantibodies as important drivers of osteoporosis. This review shall attempt to provide a comprehensive overview of existing research examining the role played by autoantibodies in osteoporosis in order to determine the potential for further research in this area. Autoantibodies represent promising targets for the improved treatment and diagnosis of inflammatory bone loss.

Effects of dietary gelatin hydrolysates on bone mineral density in magnesium-deficient rats

Background

The major types of commercially available gelatin hydrolysates are prepared from mammals or fish. Dietary gelatin hydrolysates from mammals were reported to improve bone mineral density (BMD) in some animal models. In contrast, there is limited study showing the effects of dietary gelatin hydrolysates from fish on BMD. The quantity and structure of peptides in the plasma after oral administration of gelatin hydrolysates depend on the gelatin source, which suggests that the biological activity of gelatin hydrolysates depend on the gelatin source. This study examined the effects of fish-derived gelatin hydrolysate (FGH) or porcine-derived gelatin hydrolysate (PGH) intake on BMD and intrinsic biomechanical properties in magnesium (Mg)-deficient rats as a model showing the decrease in both BMD and intrinsic biomechanical properties.

Methods

Four-week-old male Wistar rats were assigned into four groups: a normal group was fed a normal diet (48 mg Mg/100 g diet), a Mg-deficient (MgD) group was fed a MgD diet (7 mg Mg/100 g diet), a FGH group was fed a MgD + FGH diet (5% FGH), and a PGH group was fed a MgD + PGH diet (5% PGH) for 8 weeks. At the end of the study, BMD and intrinsic biomechanical properties of the femur were measured.

Results

The MgD group showed significantly lower Young’s modulus, an intrinsic biomechanical property, and trabecular BMD of the femur than the normal group; however, the MgD diet did not affect cortical BMD and cortical thickness. Both the FGH and the PGH groups showed significantly higher cortical thickness and ultimate displacement of the femur than the normal group, but neither type of gelatin hydrolysate affected Young’s modulus. Furthermore, the FGH group, but not the PGH group, showed significantly higher trabecular BMD than the MgD group.

Conclusions

This study indicates that FGH and PGH increase cortical thickness but only FGH prevents the decrease in trabecular BMD seen in Mg-deficient rats, while neither type of gelatin hydrolysate affect intrinsic biomechanical properties.

Polymorphisms in key bone modulator cytokines genes influence bisphosphonates therapy in postmenopausal women

Osteoporosis is a multifactorial and debilitating disease resulting from decreased bone mineral density (BMD) and loss of tissue microarchitecture. Ineffective therapies may lead to bone fractures and subsequent death. Single nucleotide polymorphisms (SNPs) in key immune regulator genes have been associated with therapeutic response to bisphosphonates, which are the first therapeutic line of choice for osteoporosis. However, cytokine pathways and their relation with therapeutic adhesion remain to be fully elucidated. Aimed at better understanding these processes, we investigated the response to bisphosphonate therapy in postmenopausal women and four SNPs in key proinflammatory cytokines genes: IL23R +2284 (C>A) (rs10889677), IL17A +672 (G>A) (rs7747909), IL12B +1188 (T>G) (rs3212227) and INF-γ -1616 (G>A) (rs2069705). A total of 69 patients treated with bisphosphonate were followed for a period of 1 up to 4 years, genotyped and compared according to their changes in bone mineral density (BMD) and level of biochemical markers during their treatment. The INF-γ -1616 G/G associated with increased BMD values in femoral neck (GG/AA, p = 0.016) and decreased BMD values in total hip (GG/GA, p = 0.019; GG/AA, p = 0.011). In relation to biochemical markers, INF-γ -1616 SNP associated with increased alkaline phosphatase (GG/AA; p < 0.0001) and parathyroid hormone levels (AA/GA; p = 0.017). Vitamin D values changes were related to IL17A +672 (GG/GA, p = 0.034) and to IL12B +1188 (TT/TG, p = 0.046) SNPs. Besides, significant differences in changes of calcium levels correlated with IL23R +2284 (CC/CA, p = 0.016) genotypes. Altogether, we suggest that these polymorphisms may play an important role for therapeutic decisions in osteoporosis treatment.

Denosumab: targeting the RANKL pathway to treat rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by focal pathologic bone resorption due to excessive activity of osteoclasts (OC). Receptor activator of nuclear factor kappa B ligand (RANKL) is essential for the proliferation, differentiation, and survival of OC. Denosumab (DMab) is a humanized monoclonal antibody that binds to RANKL with high affinity and blocks its subsequent association with its receptor RANK on the surface of OC precursors. Area covered: The authors review the molecular and cellular mechanisms underlying therapeutic applications of DMab, provide recent highlights on pharmacology, efficacy and safety of DMab, and discuss the potential of DMab as a novel therapeutic option for the treatment of rheumatoid arthritis. Expert opinion: Clinical results suggest that DMab is efficient both in systemic and articular bone loss in RA with limited side effects. Diminished bone erosion activity was also noted in RA patients on corticosteroids and bisphosphonates. Combination of DMab with an anti-TNF agent was not associated with increased infection rates. Collectively, these data indicate that DMab, in combination with methotrexate and possibly other conventional synthetic Disease Modifying Anti-Rheumatic Drugs (csDMARDs), is an effective, safe and cost-effective option for the treatment of RA.

Chlorogenic Acid Prevents Osteoporosis by Shp2/PI3K/Akt Pathway in Ovariectomized Rats

Cortex Eucommiae is used worldwide in traditional medicine, various constituents of Cortex Eucommiae, such as chlorogenic acid (CGA), has been reported to exert anti-osteoporosis activity in China, but the mechanism about their contribution to the overall activity is limited. The aims of this study were to determine whether chlorogenic acid can prevent estrogen deficiency-induced osteoporosis and to analyze the mechanism of CGA bioactivity. The effect of CGA on estrogen deficiency-induced osteoporosis was performed in vivo. Sixty female Sprague-Dawley rats were divided randomly among a sham-operated group and five ovariectomy (OVX) plus treatment subgroups: saline vehicle, 17α-ethinylestradiol (E2), or CGA at 9, 27, or 45 mg/kg/d. The rats’ femoral metaphyses were evaluated by micro-computed tomography (μCT). The mechanism of CGA bioactivity was investigated in vitro. Bone mesenchymal stem cells (BMSCs) were treated with CGA, with or without phosphoinositide 3-kinase (PI3K) inhibitor LY294002. BMSCs proliferation and osteoblast differentiation were assessed with 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and alkaline phosphatase, with or without Shp2 interfering RNA (RNAi). The results display that CGA at 27 and 45 mg/kg/day inhibited the decrease of bone mineral density (BMD) that induced by OVX in femur (p< 0.01), significantly promoted the levels of bone turnover markers, and prevented bone volume fraction (BV/TV), connectivity density (CoonD), trabecular number (Tb.N), trabecular thickness (Tb.Th) (all p< 0.01) to decrease and prevented the trabecular separation (Tb.Sp), structure model index (SMI)(both p< 0.01) to increase. CGA at 1 or 10 μM enhanced BMSC proliferation in a dose-dependent manner. CGA at 0.1 to 10 μM increased phosphorylated Akt (p-Akt) and cyclin D1. These effects were reversed by LY294002. CGA at 1 or 10 μM increased BMSC differentiation to osteoblasts (p< 0.01), Shp2 RNAi suppressed CGA-induced osteoblast differentiation by decreasing Shp2, p-Akt, and cyclin D1. This study found that CGA improved the BMD and trabecular micro-architecture for the OVX-induced osteoporosis. Therefore, CGA might be an effective alternative treatment for postmenopausal osteoporosis. CGA promoted proliferation of osteoblast precursors and osteoblastic differentiation of BMSCs via the Shp2/PI3K/Akt/cyclin D1 pathway.

Management of atypical femoral fracture: a scoping review and comprehensive algorithm

BACKGROUND

Atypical femoral fractures (AFF) are a rare type of femoral stress fracture recently described, potentially associated with prolonged bisphosphonate therapy. Evidence-based recommendations regarding diagnosis and management of these fractures are scarce. The purpose of this study is to propose an algorithm for the diagnosis and management of AFF.

METHODS

We performed a PubMed search of the last ten years using the keywords "atypical femoral fractures" and identified further articles through an evaluation of the publications cited in these articles. Relevant studies were included by agreement between researchers, depending on their specialization. Pertinent points of debate were discussed based on the available literature, allowing for consensus regarding the proposed management algorithm.

RESULTS

Using a systematic approach we performed a scoping review that included a total of 137 articles.

CONCLUSIONS

A practical guide for diagnosis and management of AFF based on the current concepts is proposed. In spite of the impressive large volume of published literature available since AFF were initially identified, the level of evidence is mostly poor, in particular regarding treatment choice. Therefore, further studies are required.

Changes in bone mineral density following long-term simultaneous pancreas-kidney transplantation

The symptoms of chronic renal disease-related mineral and bone disease improve significantly in patients after successful simultaneous pancreas-kidney transplantation (SPKT); however, bone pathology is still present even after many post-transplant years. The aim of this study was to analyze the bone densitometry in different periods after SPKT. Three-point densitometry was performed with the dual-energy X-ray absorptiometry (DXA) technique. Serum levels of alkaline phosphatase (ALP), total serum calcium, phosphate and parathyroid hormone were analyzed as markers of mineral metabolism. The study population consisted of 48 patients (28 females, 20 males) with a mean age of 35 ± 6 years and mean 24 ± 6 years of prior diabetes. Mean period of maintenance dialysis was 36 ± 26 months. The median time from SPKT and DXA measurement was 0.53, 26.2 and 41.9 months, respectively. Based on the DXA technique, 35.4 % of patients were categorized as having osteoporosis at the lumbar spine and 39.6 % at the femoral neck. Patients with diagnosed osteoporosis had significantly higher levels of ALP (OR = 1.5; 95 % CI = 1.1-2.2; p < 0.05 at the lumbar spine; OR = 1.4; 95 % CI = 1.0-1.9; p < 0.05 at the femoral neck). In addition, subjects with lumbar osteoporosis were characterized by a significantly lower body mass index (BMI) (OR = 0.5; 95 % CI = 0.3-0.9; p < 0.05). In the long-term follow-up, BMD increased significantly at the lumbar spine (T-score -1.86 ± 1.07 to -1.08 ± 0.89) and femoral neck (T-score -2.12 ± 0.78 to -1.63 ± 0.65). A multivariate linear model identified a BMI increase as a significant factor associated with improvement in BMD. Results of our study led us to conclude that, according to three-point densitometry, BMD among patients with functioning kidney and pancreas grafts improved. Increased serum levels of ALP were significantly associated with a decrease in BMD, suggesting a higher risk of osteoporosis. BMI gain was predictive of BMD improvement.

Changes in serum vitamin D and PTH values using denosumab with or without bisphosphonate pre-treatment in osteoporotic patients: a short-term study

BACKGROUND

Denosumab is a fully human monoclonal antibody that inhibits receptor activator of nuclear factor kappa-β ligand (RANKL). Previous reports have shown that denosumab treatment of osteoporotic patients decreases bone resorption and fracture risk, but there have been no clinical studies on changes in bone turnover markers, 1,25(OH)2D3, or parathyroid hormone (PTH) in denosumab therapy with or without bisphosphonate (BP) pre-treatment in Japan.

METHODS

Here, we report such findings in 22 patients (11 in the denosumab alone group and 11 in the BP pre-treated group) with osteoporosis following 4 months of treatment. Bone metabolism had been inhibited by prior BP administration in the BP pre-treated group.

RESULTS

The bone resorption markers serum tartrate-resistant acid phosphatase type 5b and urinary type I collagen cross-linked N-telopeptide were significantly decreased from baseline values for the entire study period in both groups. The bone formation marker bone alkaline phosphatase was significantly decreased at 4 months in the denosumab alone group only, and N-terminal propeptide of type 1 procollagen was significantly decreased at 2 and 4 months in the denosumab alone group versus no remarkable change in the BP pre-treated group. In the denosumab alone group, 1,25(OH)2D3 and PTH were significantly increased at 1 week and decreased gradually thereafter, but these did not change notably in the BP pre-treated group.

CONCLUSIONS

Our results suggest that treatment with denosumab causes a strong inhibitory effect on bone resorption markers and mild inhibitory effect on bone formation markers. 1,25(OH)2D3 and PTH were significantly increased by denosumab but these did not change in the BP pre-treated group.

TRIAL REGISTRATION

Current Controlled Trials NCT02156960. Registered 31 May 2014.

Further reductions in nonvertebral fracture rate with long-term denosumab treatment in the FREEDOM open-label extension and influence of hip bone mineral density after 3 years

Limited data exist on the efficacy of long-term therapies for osteoporosis. In osteoporotic postmenopausal women receiving denosumab for 7 years, nonvertebral fracture rates significantly decreased in years 4-7 versus years 1-3. This is the first demonstration of a further benefit on fracture outcomes with long-term therapy for osteoporosis.

INTRODUCTION

This study aimed to evaluate whether denosumab treatment continued beyond 3 years is associated with a further reduction in nonvertebral fracture rates.

METHODS

Participants who completed the 3-year placebo-controlled Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months (FREEDOM) study were invited to participate in an open-label extension. The present analysis includes 4,074 postmenopausal women with osteoporosis (n = 2,343 long-term; n = 1,731 cross-over) who enrolled in the extension, missed ≤1 dose during their first 3 years of denosumab treatment, and continued into the fourth year of treatment. Comparison of nonvertebral fracture rates during years 1-3 of denosumab with that of the fourth year and with the rate during years 4-7 was evaluated.

RESULTS

For the combined group, the nonvertebral fracture rate per 100 participant-years was 2.15 for the first 3 years of denosumab treatment (referent) and 1.36 in the fourth year (rate ratio [RR] = 0.64; 95 % confidence interval (CI) = 0.48 to 0.85, p = 0.003). Comparable findings were observed in the groups separately and when nonvertebral fracture rates during years 1-3 were compared to years 4-7 in the long-term group (RR = 0.79; 95 % CI = 0.62 to 1.00, p = 0.046). Fracture rate reductions in year 4 were most prominent in subjects with persisting low hip bone mineral density (BMD).

CONCLUSIONS

Denosumab treatment beyond 3 years was associated with a further reduction in nonvertebral fracture rate that persisted through 7 years of continuous denosumab administration. The degree to which denosumab further reduces nonvertebral fracture risk appears influenced by the hip bone density achieved with initial therapy.

Osteonecrosis of the jaw in patient with denosumab therapy

Osteonecrosis (ON) of the jaw has previously been linked to the use of biphosphonates; however, new drugs, also shown similar conditions. This article presents a female patient with mandibular ON related to the use of denosumab. The 55-year-old presented with bone exposure with 8 months of evolution after a dental extraction. The patient began subcutaneous injections of 60 mg denosumab four months prior to the extraction and the lesion remained after the procedure. The patient, with 14 months of follow-up, show mandible ON with no favorable evolution. The clinical condition is presented and the literature of ON associated with denosumab is discussed.