Ibandronate increases sclerostin levels and bone strength in male patients with idiopathic osteoporosis

Relationship Between Changes in Serum Levels of Intact Parathyroid Hormone and Sclerostin After a Single Dose of Zoledronic Acid: Results of a Phase 1 Pharmacokinetic Study

Although changes in serum sclerostin levels at 12 months after infusion of zoledronic acid have been reported, the changes in sclerostin levels at earlier time points are poorly understood. We reanalyzed the study data of a previous phase 1 pharmacokinetic study and investigated the correlation between changes in sclerostin levels and relevant factors in calcium metabolism. A total of 24 Japanese female subjects with primary postmenopausal osteoporosis were administered a single 4- or 5-mg dose of zoledronic acid. Serum and urine samples were collected on days 15, 29, 90, 180, and 365 after administration. Serum levels of calcium, phosphate, intact parathyroid hormone (iPTH), and sclerostin were measured. Levels of serum sclerostin were unchanged from baseline on days 15 and 29, but increased significantly on day 90, subsequently decreased significantly on day 180, and returned to baseline levels on day 365. A significant negative correlation was observed between changes in iPTH levels at early time points and sclerostin levels at later time points. This suggests that sclerostin was negatively regulated by iPTH, and the decrease in sclerostin may indicate the start of bone formation during later time points after zoledronic acid injection.

How to manage osteoporosis before the age of 50

This narrative review discusses several aspects of the management of osteoporosis in patients under 50 years of age. Peak bone mass is genetically determined but can also be affected by lifestyle factors. Puberty constitutes a vulnerable period. Idiopathic osteoporosis is a rare, heterogeneous condition in young adults due in part to decreased osteoblast function and deficient bone acquisition. There are no evidence-based treatment recommendations. Drugs use can be proposed to elderly patients at very high risk. Diagnosis and management of osteoporosis in the young can be challenging, in particular in the absence of a manifest secondary cause. Young adults with low bone mineral density (BMD) do not necessarily have osteoporosis and it is important to avoid unnecessary treatment. A determination of BMD is recommended for premenopausal women who have had a fragility fracture or who have secondary causes of osteoporosis: secondary causes of excessive bone loss need to be excluded and treatment should be targeted. Adequate calcium, vitamin D, and a healthy lifestyle should be recommended. In the absence of fractures, conservative management is generally sufficient, but in rare cases, such as chemotherapy-induced osteoporosis, antiresorptive medication can be used. Osteoporosis in young men is most often of secondary origin and hypogonadism is a major cause; testosterone replacement therapy will improve BMD in these patients. Diabetes is characterized by major alterations in bone quality, implying that medical therapy should be started sooner than for other causes of osteoporosis. Primary hyperparathyroidism, hyperthyroidism, Cushing's syndrome and growth hormone deficiency or excess affect cortical bone more often than trabecular bone.

Zoledronate Slows Weight Loss and Maintains Fat Mass in Osteopenic Older Women: Secondary Analysis of a Randomized Controlled Trial

Studies in mice have suggested that osteocalcin plays an important role in glucose and fat metabolism. Since anti-resorptive drugs reduce circulating levels of osteocalcin they might be associated with increased fat mass and an increased risk of diabetes. Positive changes in body weight have been found in trials of alendronate and denosumab, but no significant effect in a previous trial of zoledronate. Whether those weight differences were in fat or lean mass is unknown. There were no effects of anti-resorptive treatments on fasting glucose concentrations or incidence of diabetes in those three studies. We have used our recent trial comparing zoledronate and placebo over 6 years in 2000 older osteopenic women to re-examine these questions. Both treatment groups lost body weight during the study (placebo 1.65 kg, zoledronate 1.05 kg), and this was significantly greater in the placebo group (P = 0.01). Both groups lost lean mass, and this loss was marginally (0.17 kg) but significantly (P = 0.02) greater in those receiving zoledronate. The placebo group had a mean loss of fat mass of 0.63 kg but there was no change in fat mass in the zoledronate group (between-groups comparison, P = 0.007). In the placebo group, there were 20 new diagnoses of diabetes, and in the zoledronate group, 19 (P = 0.87). Zoledronate prevented age-related loss of fat mass in these late postmenopausal women. The present study is the first to document a significant effect of zoledronate treatment on body weight, confirming results previously found with alendronate and denosumab. It also demonstrates that this is principally an effect to maintain fat mass rather than influencing lean mass, raising an important physiological question as to how anti-resorptive drugs have this effect on intermediary metabolism. It is possible that this anti-catabolic action contributes to the beneficial effects of anti-resorptive drugs on bone and longevity.

Perspectives on the non-invasive evaluation of femoral strength in the assessment of hip fracture risk

We reviewed the experimental and clinical evidence that hip bone strength estimated by BMD and/or finite element analysis (FEA) reflects the actual strength of the proximal femur and is associated with hip fracture risk and its changes upon treatment.

INTRODUCTION

The risk of hip fractures increases exponentially with age due to a progressive loss of bone mass, deterioration of bone structure, and increased incidence of falls. Areal bone mineral density (aBMD), measured by dual-energy X-ray absorptiometry (DXA), is the most used surrogate marker of bone strength. However, age-related declines in bone strength exceed those of aBMD, and the majority of fractures occur in those who are not identified as osteoporotic by BMD testing. With hip fracture incidence increasing worldwide, the development of accurate methods to estimate bone strength in vivo would be very useful to predict the risk of hip fracture and to monitor the effects of osteoporosis therapies.

METHODS

We reviewed experimental and clinical evidence regarding the association between aBMD and/orCT-finite element analysis (FEA) estimated femoral strength and hip fracture risk as well as their changes with treatment.

RESULTS

Femoral aBMD and bone strength estimates by CT-FEA explain a large proportion of femoral strength ex vivo and predict hip fracture risk in vivo. Changes in femoral aBMD are strongly associated with anti-fracture efficacy of osteoporosis treatments, though comparable data for FEA are currently not available.

CONCLUSIONS

Hip aBMD and estimated femoral strength are good predictors of fracture risk and could potentially be used as surrogate endpoints for fracture in clinical trials. Further improvements of FEA may be achieved by incorporating trabecular orientations, enhanced cortical modeling, effects of aging on bone tissue ductility, and multiple sideway fall loading conditions.

The utility and limitations of using trabecular bone score with FRAX

PURPOSE OF REVIEW

Trabecular bone score (TBS) is a texture index derived from the lumbar spine dual-energy X-ray absorptiometry which can assess skeletal quality and provide information about fracture risk independent of bone mineral density (BMD). TBS is useful in assessing osteoporotic fracture risk, with lower TBS values associated with increased fracture risk. In this article, we review the current state of TBS, including its utility and limitations in the assessment and management of osteoporosis, with particular emphasis on the recent literature.

RECENT FINDINGS

Ten-year fracture risk assessment using the FRAX tool can be improved through the use of a TBS adjustment. The use of TBS-adjusted FRAX can change management in a modest but significant number of patients, particularly in those close to an intervention threshold. Change in lumbar spine TBS for patients undergoing antiresorptive treatment is not a useful indicator of antifracture effect.

SUMMARY

Lumbar spine TBS provides information complementary to conventional BMD, and has been shown to be clinically useful for enhancing fracture risk prediction.

Screening of differentially expressed genes in male idiopathic osteoporosis via RNA sequencing

As a type of osteoporosis (OP), male idiopathic OP (MIO) is a bone disorder that occurs in young males and is a public health problem worldwide. However, the detailed pathogenesis of MIO remains to be elucidated. In the present study, blood samples of patients with MIO, senile OP, postmenopausal OP and normal controls (NCs) were obtained for RNA sequencing. Compared with the NC group, differentially expressed genes (DEGs) in the three types of OP were identified. DEGs that were common among the three types of OP and the DEGs that were unique to patients with MIO were determined. Gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted. MIO‑specific and OP‑specific protein‑protein interaction (PPI) networks were constructed. Compared with NCs, a total of 519, 368 and 1,472 DEGs were identified in samples from MIO, senile OP and postmenopausal OP, respectively. Tetraspanin 5 (TSPAN5) and α‑synuclein (SNCA) were unique DEGs in MIO that were not identified in the other two types of OP compared with NCs. Furthermore, the expression of carbonic anhydrase 1 (CA1) and S100 calcium‑binding protein P (S100P) in MIO was significantly different compared with senile OP, postmenopausal OP and NC samples. 'MAPK signaling pathway', 'type I diabetes mellitus' and 'hematopoietic cell lineage' were among significantly enriched pathways of DEGs in MIO. SNCA and CDC‑like kinase 1 were the hub genes in the MIO‑specific PPI network. In conclusion, the mitogen‑activated protein kinase signaling and type I diabetes mellitus pathways may be involved in bone formation; SNCA and TSPAN5 may be associated with bone resorption. These two pathways and two genes may serve a role in MIO. CA1 and S100P may regulate the process of MIO by modulation of calcification and dysregulation of calcium binding. These findings may have provided an experimental basis for elucidating the underlying mechanisms and developing potential diagnostic biomarkers of MIO.

Bone-related Circulating MicroRNAs miR-29b-3p, miR-550a-3p, and miR-324-3p and their Association to Bone Microstructure and Histomorphometry

The assessment of bone quality and the prediction of fracture risk in idiopathic osteoporosis (IOP) are complex prospects as bone mineral density (BMD) and bone turnover markers (BTM) do not indicate fracture-risk. MicroRNAs (miRNAs) are promising new biomarkers for bone diseases, but the current understanding of the biological information contained in the variability of miRNAs is limited. Here, we investigated the association between serum-levels of 19 miRNA biomarkers of idiopathic osteoporosis to bone microstructure and bone histomorphometry based upon bone biopsies and µCT (9.3 μm) scans from 36 patients. Four miRNAs were found to be correlated to bone microarchitecture and seven miRNAs to dynamic histomorphometry (p < 0.05). Three miRNAs, namely, miR-29b-3p, miR-324-3p, and miR-550a-3p showed significant correlations to histomorphometric parameters of bone formation as well as microstructure parameters. miR-29b-3p and miR-324-p were found to be reduced in patients undergoing anti-resorptive therapy. This is the first study to report that serum levels of bone-related miRNAs might be surrogates of dynamic histomorphometry and potentially reveal changes in bone microstructure. Although these findings enhance the potential value of circulating miRNAs as bone biomarkers, further experimental studies are required to qualify the clinical utility of miRNAs to reflect dynamic changes in bone formation and microstructure.

The role of sclerostin/dickkopf-1 and receptor activator of nuclear factor kB ligand/osteoprotegerin signalling pathways in the development of osteoporosis in patients with haemophilia A and B: A cross-sectional study

AIM

Haemophilia A and B are associated with reduced bone mineral density (BMD). The aim of this study was to assess circulating sclerostin and dickkopf-1 (Dkk-1), (inhibitors of osteoblastic differentiation), as well as the receptor activator of nuclear factor kB ligand (RANKL)/osteoprotegerin (OPG) system (the major regulator of osteoclastogenesis), in patients with haemophilia (PWH), their possible correlations with clinical risk factors and the effect of ibandronate on these markers.

METHODS

Eighty-nine male PWH (mean age 45.9 ± 15.3 years) and 30 age-matched healthy male controls participated. BMD was assessed by DXA. Sclerostin, Dkk-1, RANKL and OPG were measured in serum of patients, controls, as well as in ten patients receiving oral ibandronate (150 mg/mo), at baseline and after 12 months.

RESULTS

Patients with haemophilia had lower circulating sclerostin (median ± IQR: 47.4 ± 26.93 vs 250 ± 250 pmol/L, P < .001), Dkk-1 (21.24 ± 17.18 vs 26.16 ± 15.32pg/mL, P = .04) and higher levels of RANKL (0.23 ± 0.03 vs 0.04 ± 0.03 pmol/L, P = .001), RANKL/OPG ratio (0.063 ± 0.25 vs 0.005 ± 0.11, P = .001) compared with controls. Patients with low BMD had higher OPG concentrations compared to those with normal BMD. Sclerostin and RANKL/OPG correlated positively with BMD. Patients with severe haemophilia had lower sclerostin concentrations compared with those with mild or moderate disease. The degree of arthropathy negatively correlated with sclerostin and Dkk-1 levels. PWH who received ibandronate showed a decrease in serum Dkk-1 without any significant effect on sclerostin and RANKL/OPG.

CONCLUSIONS

Patients with haemophilia present increased osteoclastic activity coupled with compensatory increased osteoblastic activity. Ibandronate did not affect RANKL/OPG ratio, but it decreased Dkk-1.

Preceding and subsequent high- and low-trauma fracture patterns-a 13-year epidemiological study in females and males in Austria

This study investigated the implication of a preceding high-trauma fracture on subsequent high- and low-trauma fractures at different skeletal sites in postmenopausal women and similarly aged men at an age range of 54 to 70 years. A preceding high-trauma fracture increases the risk of future low-trauma non-vertebral fractures including hip.

INTRODUCTION

Little is known about the impact of the skeletal fracture site in conjunction with the severity of a past fracture (high- or low-trauma preceding fracture) and its effect on future fracture risk.

METHODS

Patients with de novo high- and low-trauma fractures admitted to seven large trauma centers across Austria between 2000 and 2012 were stratified into sex and different age groups. Kaplan-Meier estimates, Cox proportional hazards regression models (HR), and likelihood calculations estimated effects of age, sex, and the anatomic region on the probability of a subsequent fracture in the same patient.

RESULTS

Included in the study were 433,499 female and male patients at an age range of 0 to 100 years with 575,772 de novo high- and low-trauma fractures. In the age range of 54-70 years, subsequent fractures were observed in 16% of females and 12.1% of males. A preceding high-trauma fracture was associated with 12.9% of subsequent fractures, thereof 6.5% of high- and 6.4% of low-trauma in origin, usually at the hip, humerus, or pelvis. The highest effect sizes were observed for femur, humerus, and thorax fractures with hazard ratios (HR) of 1.26, 1.18, and 1.14. After splitting into high-trauma preceding and subsequent low-trauma fractures, the femoral neck (HR = 1.59), the female sex (HR = 2.02), and age (HR = 1.03) were discriminators for increased future fracture risk.

CONCLUSIONS

Preceding high-trauma fractures increase the risk of future low-trauma non-vertebral fractures including hip. For each patient with a fracture, regardless of the severity of the trauma, osteoporosis should be taken into clinical consideration.

Circulating microRNA Signatures in Patients With Idiopathic and Postmenopausal Osteoporosis and Fragility Fractures

CONTEXT

Established bone turnover markers do not reflect fracture risk in idiopathic male and premenopausal osteoporosis and the role of microRNAs (miRNAs) in these patients is currently unclear. miRNAs are a class of small non-coding RNAs that regulate gene expression and bone tissue homeostasis. They are considered a new class of endocrine regulators with promising potential as biomarkers.

OBJECTIVE

Evaluation of circulating miRNA signatures in male and female subjects with idiopathic and postmenopausal osteoporotic low-traumatic fractures.

DESIGN, SETTING, AND PATIENTS

This was a case-control study of cross-sectional design of 36 patients with prevalent low-traumatic fractures and 39 control subjects Main Outcome Measures: One hundred eighty-seven miRNAs were quantified in serum by qPCR, compared between groups and correlated with established bone turnover markers.

RESULTS

Significant differences in serum levels of circulating miRNAs were identified in all three subgroups (46 in premenopausal, 52 in postmenopausal, 55 in male). A set of 19 miRNAs was consistently regulated in all three subgroups. Eight miRNAs [miR-152-3p, miR-30e-5p, miR-140-5p, miR-324-3p, miR-19b-3p, miR-335-5p, miR-19a-3p, miR-550a-3p] were excellent discriminators of patients with low-traumatic fractures, regardless of age and sex, with area under the curve values > 0.9. The 11 remaining miRNAs showed area under the curve values between 0.81 and 0.89. Correlation analysis identified significant correlations between miR-29b-3p and P1NP, and miR-365-5p and iPTH, TRAP5b, P1NP and Osteocalcin, as well as BMD_L1-L4 and miR-19b-3p, miR-324-3p, miR-532-5p, and miR-93-5p.

CONCLUSIONS

Specific serum miRNA profiles are strongly related to bone pathologies. Therefore miRNAs might be directly linked to bone tissue homeostasis. In particular, miR-29b-3p has previously been reported as regulator of osteogenic differentiation and could serve as a novel marker of bone turnover in osteoporotic patients as a member of a miRNA signature.

Trabecular bone score (TBS) as a new complementary approach for osteoporosis evaluation in clinical practice

Trabecular bone score (TBS) is a recently-developed analytical tool that performs novel grey-level texture measurements on lumbar spine dual X-ray absorptiometry (DXA) images, and thereby captures information relating to trabecular microarchitecture. In order for TBS to usefully add to bone mineral density (BMD) and clinical risk factors in osteoporosis risk stratification, it must be independently associated with fracture risk, readily obtainable, and ideally, present a risk which is amenable to osteoporosis treatment. This paper summarizes a review of the scientific literature performed by a Working Group of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis. Low TBS is consistently associated with an increase in both prevalent and incident fractures that is partly independent of both clinical risk factors and areal BMD (aBMD) at the lumbar spine and proximal femur. More recently, TBS has been shown to have predictive value for fracture independent of fracture probabilities using the FRAX® algorithm. Although TBS changes with osteoporosis treatment, the magnitude is less than that of aBMD of the spine, and it is not clear how change in TBS relates to fracture risk reduction. TBS may also have a role in the assessment of fracture risk in some causes of secondary osteoporosis (e.g., diabetes, hyperparathyroidism and glucocorticoid-induced osteoporosis). In conclusion, there is a role for TBS in fracture risk assessment in combination with both aBMD and FRAX.