Sarcopenia phenotype and impaired muscle function in male mice with fast-twitch muscle-specific knockout of the androgen receptor.

Sarcopenia is distinct from normal muscle atrophy in that it is closely related to a shift in the muscle fiber type. Deficiency of the anabolic action of androgen on skeletal muscles is associated with sarcopenia; however, the function of the androgen receptor (AR) pathway in sarcopenia remains poorly understood. We generated a mouse model (fast-twitch muscle-specific AR knockout [fmARKO] mice) in which the AR was selectively deleted in the fast-twitch muscle fibers. In young male mice, the deletion caused no change in muscle mass, but it reduced muscle strength and fatigue resistance and induced a shift in the soleus muscles from fast-twitch fibers to slow-twitch fibers (14% increase, P = 0.02). After middle age, with the control mice, the male fmARKO mice showed much less muscle function, accompanied by lower hindlimb muscle mass; this phenotype was similar to the progression of sarcopenia. The bone mineral density of the femur was significantly reduced in the fmARKO mice, indicating possible osteosarcopenia. Microarray and gene ontology analyses revealed that in male fmARKO mice, there was downregulation of polyamine biosynthesis-related geneswhich was confirmed by liquid chromatography-tandem mass spectrometry assay and the primary cultured myofibers. None of the AR deletion-related phenotypes were observed in female fmARKO mice. Our findings showed that the AR pathway had essential muscle type- and sex-specific roles in the differentiation toward fast-twitch fibers and in the maintenance of muscle composition and function. The AR in fast-twitch muscles was the dominant regulator of muscle fiber-type composition and muscle function, including the muscle-bone relationship.

In vivo treatment with calcilytic of CaSR knock-in mice ameliorates renal phenotype reversing downregulation of the vasopressin-AQP2 pathway.

High concentrations of urinary calcium counteract vasopressin action via the activation of the Calcium-Sensing Receptor (CaSR) expressed in the luminal membrane of the collecting duct cells, which impairs the trafficking of aquaporin-2 (AQP2). In line with these findings, we provide evidence that, with respect to wild-type mice, CaSR knock-in (KI) mice mimicking autosomal dominant hypocalcaemia, display a significant decrease in the total content of AQP2 associated with significantly higher levels of AQP2 phosphorylation at Ser261, a phosphorylation site involved in AQP2 degradation. Interestingly, KI mice also had significantly higher levels of phosphorylated p38MAPK, a downstream effector of CaSR and known to phosphorylate AQP2 at Ser261. Moreover, ATF1 phosphorylated at Ser63, a transcription factor downstream of p38MAPK, was significantly higher in KI. In addition, KI mice had significantly higher levels of AQP2-targeting miRNA137 consistent with a post-transcriptional downregulation of AQP2. In vivo treatment of KI mice with the calcilytic JTT-305, a CaSR antagonist, increased AQP2 expression and reduced AQP2-targeting miRNA137 levels in KI mice. Together, these results provide direct evidence for a critical role of CaSR in impairing both short-term vasopressin response by increasing AQP2-pS261, as well as AQP2 abundance, via the p38MAPK-ATF1-miR137 pathway. KEY POINTS: Calcium-Sensing Receptor (CaSR) activating mutations are the main cause of autosomal dominant hypocalcaemia (ADH) characterized by inappropriate renal calcium excretion leading to hypocalcaemia and hypercalciuria. Current treatments of ADH patients with parathyroid hormone, although improving hypocalcaemia, do not improve hypercalciuria or nephrocalcinosis. In vivo treatment with calcilytic JTT-305/MK-5442 ameliorates most of the ADH phenotypes of the CaSR knock-in mice including hypercalciuria or nephrocalcinosis and reverses the downregulation of the vasopressin-sensitive aquaporin-2 (AQP2) expression, providing direct evidence for a critical role of CaSR in impairing vasopressin response. The beneficial effect of calcilytic in reducing the risk of renal calcification may occur in a parathyroid hormone-independent action through vasopressin-dependent inhibition of cAMP synthesis in the thick ascending limb and in the collecting duct. The amelioration of most of the abnormalities in calcium metabolism including hypercalciuria, renal calcification, and AQP2-mediated osmotic water reabsorption makes calcilytic a good candidate as a novel therapeutic agent for ADH.

Bone-fat linkage via interleukin-11 in response to mechanical loading.

Positive regulators of bone formation, such as mechanical loading and PTH, stimulate and negative regulators, such as aging and glucocorticoid excess, suppress IL-11 gene transcription in osteoblastic cells. Signal transduction from mechanical loading and PTH stimulation involves two pathways: one is Ca2+-ERK-CREB pathway which facilitates binding of ∆FosB/JunD to the AP-1 site to enhance IL-11 gene transcription, and the other is Smad1/5 phosphorylation that promotes IL-11 gene transcription via SBE binding and complex formation with ∆FosB/JunD. The increased IL-11 suppresses Sost expression via IL-11Rα-STAT1/3-HDAC4/5 pathway and enhances Wnt signaling in the bone to stimulate bone formation. Thus, IL-11 mediates stimulatory and inhibitory signals of bone formation by affecting Wnt signaling. Physiologically important stimulation of bone formation is exercise-induced mechanical loading, but exercise simultaneously requires energy source for muscle contraction. Exercise-induced stimulation of IL-11 expression in the bone increases the secretion of IL-11 from the bone. The increased circulating IL-11 acts like a hormone to enhance adipolysis as an energy source with a reduction in adipogenic differentiation via a suppression of Dkk1/2 expression in the adipose tissue. Such bone-fat linkage can be a mechanism whereby exercise increases bone mass and, at the same time, maintains energy supply from the adipose tissue.

Androgen deprivation therapy-related fracture risk in prostate cancer: an insurance claims database study in Japan.

INTRODUCTION: Androgen deprivation therapy (ADT) is widely used for the treatment of prostate cancer. ADT is associated with reduced bone density leading to an increased risk of osteoporotic fracture. The objective of this retrospective cohort study was to quantify fracture risk in men treated with ADT for prostate cancer in real-world practice in Japan. MATERIALS AND METHODS: Data were extracted from the Japanese Medical Data Vision (MDV) database. Men initiating ADT for treatment of prostate cancer between April 2010 and March 2021 were identified and matched to a cohort of prostate cancer patients not taking ADT using a propensity score. Fracture rates were estimated by a cumulative incidence function and compared between cohorts using a Cox cause-specific hazard model. Information was extracted on demographics, comorbidities and bone densitometry. RESULTS: 30,561 men with PC starting ADT were matched to 30,561 men with prostate cancer not treated with ADT. Following ADT initiation, <5% of men underwent bone densitometry. Prescription of ADT was associated with an increased fracture risk compared to not taking ADT (adjusted hazard ratio: 1.63 [95% CI 1.52-1.75]). CONCLUSION: ADT is associated with a 1.6-fold increase in the risk of osteoporotic fracture in men with prostate cancer. Densitometry in this population is infrequent and monitoring urgently needs to be improved in order to implement effective fracture prevention.

Inflammatory Cytokine-Induced Muscle Atrophy and Weakness Can Be Ameliorated by an Inhibition of TGF-ß-Activated Kinase-1.

Chronic inflammation causes muscle wasting. Because most inflammatory cytokine signals are mediated via TGF-ß-activated kinase-1 (TAK1) activation, inflammatory cytokine-induced muscle wasting may be ameliorated by the inhibition of TAK1 activity. The present study was undertaken to clarify whether TAK1 inhibition can ameliorate inflammation-induced muscle wasting. SKG/Jcl mice as an autoimmune arthritis animal model were treated with a small amount of mannan as an adjuvant to enhance the production of TNF-α and IL-1ß. The increase in these inflammatory cytokines caused a reduction in muscle mass and strength along with an induction of arthritis in SKG/Jcl mice. Those changes in muscle fibers were mediated via the phosphorylation of TAK1, which activated the downstream signaling cascade via NF-κB, p38 MAPK, and ERK pathways, resulting in an increase in myostatin expression. Myostatin then reduced the expression of muscle proteins not only via a reduction in MyoD1 expression but also via an enhancement of Atrogin-1 and Murf1 expression. TAK1 inhibitor, LL-Z1640-2, prevented all the cytokine-induced changes in muscle wasting. Thus, TAK1 inhibition can be a new therapeutic target of not only joint destruction but also muscle wasting induced by inflammatory cytokines.

Abaloparatide dose-dependently increases bone mineral density in postmenopausal women with osteoporosis: a phase 2 study.

INTRODUCTION: This study aimed to determine the efficacy of abaloparatide in increasing bone mineral density (BMD) and its safety in postmenopausal Japanese women with osteoporosis. MATERIALS AND METHODS: Randomized, double-blind, placebo-controlled, dose-finding study of abaloparatide in postmenopausal Japanese women at high fracture risk. The primary endpoint was the change in lumbar spine (LS) BMD from baseline at the last visit after daily subcutaneous injections of placebo or 40 or 80 µg abaloparatide. Other endpoints included time-course changes in LS BMD at 12, 24, and 48 weeks, in total hip (TH) and femoral neck (FN) BMDs, and in bone turnover markers. RESULTS: Increases in LS BMD with 40 and 80 µg abaloparatide were significantly higher than that with placebo (6.6% and 11.5%, respectively), with significant between-group differences for the abaloparatide groups (4.9%). TH BMD increased by 0.4%, 1.6%, and 2.9% and FN BMD increased by 0.6%, 1.5%, and 2.4% in the placebo and 40 and 80 µg abaloparatide groups, respectively. Serum PINP rapidly increased by 67.3% and 140.7% and serum CTX slowly increased by 16.4% and 34.5% in the 40 and 80 µg abaloparatide groups, respectively. Although more adverse events were observed in the abaloparatide groups, they were mild to moderate and not dose dependent. CONCLUSION: In postmenopausal Japanese women with osteoporosis at high fracture risk, abaloparatide for 48 weeks dose-dependently increased LS, TH, and FN BMDs, supporting further investigation with 80 µg abaloparatide for the treatment of osteoporosis in this population. TRIAL REGISTRATION NUMBER: JapicCTI-132381.

Asia-pacific consensus on osteoporotic fracture prevention in postmenopausal women with low bone mass or osteoporosis but no fragility fractures.

Postmenopausal women are at significant risk for osteoporotic fractures due to their rapid bone loss. Half of all postmenopausal women will get an osteoporosis-related fracture over their lifetime, with 25% developing a spine deformity and 15% developing a hip fracture. By 2050, more than half of all osteoporotic fractures will occur in Asia, with postmenopausal women being the most susceptible. Early management can halt or even reverse the progression of osteoporosis. Consequently, on October 31, 2020, the Taiwanese Osteoporosis Association hosted the Asia-Pacific (AP) Postmenopausal Osteoporotic Fracture Prevention (POFP) consensus meeting, which was supported by the Asian Federation of Osteoporosis Societies (AFOS) and the Asia Pacific Osteoporosis Foundation (APOF). International and domestic experts developed ten applicable statements for the prevention of osteoporotic fractures in postmenopausal women with low bone mass or osteoporosis but no fragility fractures in the AP region. The experts advocated, for example, that postmenopausal women with a high fracture risk be reimbursed for pharmaceutical therapy to prevent osteoporotic fractures. More clinical experience and data are required to modify intervention tactics.

Activation of unliganded FGF receptor by extracellular phosphate potentiates proteolytic protection of FGF23 by its O-glycosylation.

Fibroblast growth factor (FGF) 23 produced by bone is a hormone that decreases serum phosphate (Pi). Reflecting its central role in Pi control, serum FGF23 is tightly regulated by serum Pi alterations. FGF23 levels are regulated by the transcriptional event and posttranslational cleavage into inactive fragments before its secretion. For the latter, O-glycosylation of FGF23 by GALNT3 gene product prevents the cleavage, leading to an increase in serum FGF23. However, the molecular basis of Pi sensing in the regulation of serum FGF23 remains elusive. In this study, we showed that high Pi diet enhanced the skeletal expression of Galnt3, but not Fgf23, with expected increases in serum FGF23 and Pi in mice. Galnt3 induction by high Pi was further observed in osteoblastic UMR 106 cells, and this was mediated by activation of the extracellular signal-regulated kinase (ERK) pathway. Through proteomic searches for the upstream sensor for high Pi, we identified one subtype of the FGF receptor (FGFR1c), which was phosphorylated by high Pi in the absence of FGFs. The mode of unliganded FGFR activation by high Pi appeared different from that of FGFR bound to a canonical FGFR ligand (FGF2) when phosphorylation of the FGFR substrate 2α and ERK was monitored. Finally, we showed that an FGFR inhibitor and conditional deletion of Fgfr1 in osteoblasts/osteocytes abrogated high Pi diet-induced increases in serum FGF23 and femoral Galnt3 expression in mice. Thus, these findings uncover an unrecognized facet of unliganded FGFR function and illustrate a Pi-sensing pathway involved in regulation of FGF23 production.

TAK1 is a pivotal therapeutic target for tumor progression and bone destruction in myeloma.

Along with the tumor progression, the bone marrow microenvironment is skewed in multiple myeloma (MM), which underlies the unique pathophysiology of MM and confers aggressiveness and drug resistance in MM cells. TGF-ß-activated kinase-1 (TAK1) mediates a wide range of intracellular signaling pathways. We demonstrate here that TAK1 is constitutively overexpressed and phosphorylated in MM cells, and that TAK1 inhibition suppresses the activation of NF-κB, p38MAPK, ERK and STAT3 to decrease the expression of critical mediators for MM growth and survival, including PIM2, MYC, Mcl-1, IRF4, and Sp1, along with a substantial reduction in the angiogenic factor VEGF in MM cells. Intriguingly, TAK1 phosphorylation was also induced along with upregulation of vascular cell adhesion molecule-1 (VCAM-1) in bone marrow stromal cells (BMSCs) in cocultures with MM cells, which facilitated MM cell-BMSC adhesion while inducing IL-6 production and receptor activator of nuclear factor κ-Β ligand (RANKL) expression by BMSCs. TAK1 inhibition effectively impaired MM cell adhesion to BMSCs to disrupt the support of MM cell growth and survival by BMSCs. Furthermore, TAK1 inhibition suppressed osteoclastogenesis enhanced by RANKL in cocultures of bone marrow cells with MM cells, and restored osteoblastic differentiation suppressed by MM cells or inhibitory factors for osteoblastogenesis overproduced in MM. Finally, treatment with the TAK1 inhibitor LLZ1640-2 markedly suppressed MM tumor growth and prevented bone destruction and loss in mouse MM models. Therefore, TAK1 inhibition may be a promising therapeutic option targeting not only MM cells but also the skewed bone marrow microenvironment in MM.

Sclerostin: from bench to bedside.

Skeletal integrity is maintained by a meticulous balance between bone resorption and bone formation, and recent studies have revealed the essential role of canonical Wnt signaling pathways in maintaining skeletal homeostasis. The SOST gene, which encodes sclerostin, a member of Dan family glycoproteins, was originally identified as the gene responsible for two sclerosing bone dysplasias, sclerosteosis and van Buchem disease. Sclerostin is highly expressed by osteocytes, negatively regulates canonical Wnt signaling pathways by binding to low-density lipoprotein receptor-related protein (LRP) 5/6, and suppresses osteoblast differentiation and/or function. Romosozumab, a specific anti-sclerostin antibody, inhibits sclerostin-LRP5/6 interactions and indirectly activates canonical Wnt signaling pathways and bone formation. This review focuses on the mechanism of action of sclerostin and summarizes clinical studies that demonstrated the efficacy of romosozumab to increase bone mineral density and reduce osteoporotic fractures, as well as its cardiovascular safety.

RANKL as a target for the treatment of osteoporosis.

Osteoporosis is characterized by compromised bone strength, predisposing to an increased risk of fracture. Because bone is constantly remodeled, and bone mass and structure are determined by the balance between bone resorption and bone formation, it is important to maintain normal bone turnover. Therefore, therapies that reduce bone resorption have been the mainstream of osteoporosis treatment. Receptor activator of nuclear factor-kappa B ligand (RANKL)-RANK signaling was found to play a pivotal role in the regulation of osteoclastic bone resorption, and inhibition of RANKL-RANK system has become an important therapeutic target for the treatment of osteoporosis. Denosumab, a fully human monoclonal anti-RANKL neutralizing antibody, is developed as a drug for the treatment of osteoporosis. This review summarized pharmacokinetic and pharmacodynamic properties of denosumab, clinical studies including phase 2 dose-ranging and its extension study, phase 3 fracture prevention study (FREEDOM) with extension up to 10 years, studies on male osteoporosis (ADAMO study), and on glucocorticoid-induced osteoporosis, along with relevant clinical studies in Japan. In addition, mechanism of denosumab action that can explain its long-term sustained effects, combination and sequential treatment as well as the problems in discontinuation of denosumab, and finally safety of denosumab therapy is discussed.

Consensus Statement on the Use of Bone Turnover Markers for Short-Term Monitoring of Osteoporosis Treatment in the Asia-Pacific Region.

Osteoporosis is a major health issue. By 2050, a greater than 2-fold increase in patients number with hip fractures will occur in Asia representing 50% of all hip fractures worldwide. For the Asia-Pacific (AP) region, more efforts on controlling osteoporosis and the subsequent fractures are crucial. Bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) is commonly used to diagnose osteoporosis and monitor osteoporosis treatment. However, the inconvenience, cost, limited availability of DXA and the delay in detection of BMD changes after treatment initiation support an important role for bone turnover markers (BTMs), as short-term tools to monitor therapy. With regards to low adherence rates of medical treatment of osteoporosis, the experts reached consensus on the use of BTMs for both raising awareness and short-term monitoring of osteoporosis treatment in the AP region. The experts endorse the use of BTMs, especially serum C-terminal telopeptide of type 1 collagen (CTX) and serum procollagen type 1 N propeptide (P1NP), as short-term monitoring tools to help clinicians assess the responses to osteoporosis therapies and appropriately adjust treatment regimens earlier than BMD. Either the absolute values or the degree of change from baseline in BTMs can be used to monitor the potential efficacy of osteoporosis therapies. The use of BTMs can be incorporated in osteoporosis care programs, such as fracture liaison service (FLS), to improve patient adherence and treatment outcomes. Encouraging sufficient reimbursement from health care systems may facilitate widespread use of BTMs in clinical practice in the AP region.

Relationship Between Bone Mineral Density and Risk of Vertebral Fractures with Denosumab Treatment in Japanese Postmenopausal Women and Men with Osteoporosis.

In this post hoc analysis of the Denosumab Fracture Intervention Randomized Placebo-Controlled Trial (DIRECT) in Japanese postmenopausal women and men with osteoporosis, we evaluated the relationship between vertebral fracture risk and both bone mineral density (BMD) T-score and percent change after 24 months of denosumab treatment at total hip, femoral neck, and lumbar spine. Logistic regression analysis was performed and the proportion of treatment effect explained by BMD in vertebral fracture risk was estimated. The results demonstrate that both total hip BMD T-score and change can be strong predictors of subsequent fracture risk, and that total hip BMD change explained 73%, while T-score explained 23%, of the treatment effect. In contrast, neither femoral neck BMD change nor T-score can predict the effect of denosumab on vertebral fracture risk. Furthermore, although lumbar spine BMD T-score was associated with vertebral fracture incidence, lumbar spine BMD change was inversely related to vertebral fracture risk. Because there was no relationship between lumbar spine BMD change and T-score at 24 months of denosumab treatment, and because there can be small undetectable vertebral deformities that may increase BMD values, these results suggest that lumbar spine BMD change is not a good surrogate for vertebral fracture risk assessment. It is suggested that both total hip BMD change and T-score can be good surrogates for predicting vertebral fracture risk in Japanese patients with osteoporosis under denosumab treatment.ClinicalTrials.gov identifier: NCT00680953.

How do we sense phosphate to regulate serum phosphate level?

Abnormal phosphate levels result in several pathological conditions such as rickets/osteomalacia and ectopic calcification indicating that there must be a system that regulates phosphate level within a narrow range. FGF23 has been shown to be an essential hormone regulating serum phosphate level. FGF23 binds to Klotho-FGF receptor complex to reduce serum phosphate level. Several reports suggested that FGF receptor is involved in the regulation of FGF23 production. It has been also shown that high extracellular phosphate can activate several intracellular signaling pathways. However, it has been unclear whether and how phosphate regulates FGF23 production in vivo. Our recent results indicate that high extracellular phosphate directly activates FGF receptor 1 and the downstream intracellular signaling enhances FGF23 production. Thus, there is a negative feedback system for the regulation of serum phosphate level involving FGF receptor and FGF23. We propose that FGF receptor works at least as one of phosphate sensors in the maintenance of serum phosphate level.

Efficacy of denosumab co-administered with vitamin D and Ca by baseline vitamin D status.

INTRODUCTION: In anti-osteoporosis drug trials, vitamin D and calcium (Ca) are common supplements; however, the optimal dose of each is unclear. Using data from the randomized, double-blind, placebo-controlled DIRECT trial, we assessed whether baseline serum 25-hydroxy vitamin D (25[OH]D) level influences the efficacy of denosumab co-administered with vitamin D and Ca. MATERIALS AND METHODS: In this prespecified sub-analysis, subjects with primary osteoporosis who received denosumab or placebo, plus vitamin D (≥ 400 IU/day) and Ca (≥ 600 mg/day), were classified as 25(OH)D deficient (< 20 ng/mL), insufficient (≥ 20 to < 30 ng/mL), and sufficient (≥ 30 ng/mL). Study endpoints included absolute serum 25(OH)D level at baseline, 12 months, and 24 months; change in serum 25(OH)D and bone mineral density (BMD) status from baseline; and incidence of new vertebral fractures at 24 months. RESULTS: In 475 denosumab-treated and 481 placebo-treated subjects, proportions with deficient/insufficient/sufficient 25(OH)D at baseline were 53.1%/37.1%/9.9% and 50.9%/42.0%/7.1%, respectively. Supplementation significantly increased mean serum 25(OH)D levels; at 24 months, mean levels were > 30 ng/mL (sufficient) in both treatment groups. Increase in BMD over time was higher in the denosumab group vs. placebo group in all three vitamin D status groups. At month 24, denosumab-treated subjects with deficient/insufficient baseline 25(OH)D had a significantly lower risk of new vertebral fracture vs. placebo-treated subjects. CONCLUSION: Among DIRECT trial subjects supplemented with ≥ 400 IU/day of vitamin D and ≥ 600 mg/day of Ca, baseline 25(OH)D sufficiency may not influence the efficacy of denosumab in increasing BMD or preventing vertebral fractures.

Eldecalcitol is superior to alfacalcidol in maintaining bone mineral density in glucocorticoid-induced osteoporosis patients (e-GLORIA).

INTRODUCTION: Eldecalcitol increases bone mineral density (BMD) and reduces vertebral fracture in patients with primary osteoporosis. However, the effect of eldecalcitol on BMD and fracture in glucocorticoid-induced osteoporosis (GIO) patients is unknown. This study was undertaken to compare the effect of eldecalcitol on BMD and fracture with that of alfacalcidol in GIO patients. MATERIALS AND METHODS: A randomized, open-label, parallel group study was conducted to identify the effectiveness and safety of monotherapy with 0.75 µg eldecalcitol compared with 1.0 µg alfacalcidol in GIO patients. RESULTS: Lumbar spine BMD increased with eldecalcitol, but decreased with alfacalcidol at 12 and 24 months (between group difference 1.29%, p < 0.01, and 1.10%, p < 0.05, respectively). Total hip and femoral neck BMD were maintained until 24 months by eldecalcitol, but decreased by alfacalcidol (between group difference 0.97%, p < 0.05 and 1.22%, p < 0.05, respectively). Both bone formation and resorption markers were more strongly suppressed by eldecalcitol than by alfacalcidol. Eldecalcitol showed better effect on BMD than alfacalcidol in patients with no prevalent fracture and BMD > 70% of the young adult mean, and with ≤ 3 months of previous glucocorticoid treatment. No significant difference in the incidence of vertebral fracture was found, and the incidence of adverse events was similar between the two groups. CONCLUSIONS: Eldecalcitol was more effective than alfacalcidol in maintaining BMD in GIO patients. Because eldecalcitol was effective in patients with no or short-term previous glucocorticoid treatment, as well as those without prevalent fracture or low BMD, eldecalcitol can be a good candidate for primary prevention of GIO. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000011700.

Minodronate combined with alfacalcidol versus alfacalcidol alone for glucocorticoid-induced osteoporosis: a multicenter, randomized, comparative study.

INTRODUCTION: This study compared the clinical usefulness of minodronate (50 mg/4 weeks) plus alfacalcidol (1 µg/day) (Group M) with that of alfacalcidol alone (1 µg/day) (Group A) for treating glucocorticoid-induced osteoporosis. MATERIALS AND METHODS: The primary endpoints were the changes from baseline in lumbar spine (LS) bone mineral density (BMD) and the cumulative incidence of vertebral fracture at 24 months; secondary endpoints included the changes from baseline in total hip (TH) BMD and bone turnover markers. RESULTS: Of 164 patients enrolled, 152 (Group M, n = 75; Group A, n = 77) were included in the analysis of efficacy. At each time point and at 24 months, LS BMD and TH BMD were significantly higher in Group M than in Group A. The 152 patients were divided into two subgroups that were previously treated with glucocorticoids for ≤ 3 months or > 3 months. In both subgroups, the changes from baseline in LS BMD and TH BMD from baseline at 24 months had increased more in Group M than in Group A. There were no differences found in the incidence of vertebral fracture between the groups, because the number of enrolled patients was lesser than that initially expected. In Group M, both bone formation and resorption markers significantly decreased from baseline at 3 months and maintained at 6, 12, and 24 months. CONCLUSIONS: Minodronate plus alfacalcidol was more effective than alfacalcidol alone in increasing BMD and was effective in increasing BMD for both prevention and treatment. Therefore, minodronate can be a good candidate drug for the treatment of glucocorticoid-induced osteoporosis.

Management manual for cancer treatment-induced bone loss (CTIBL): position statement of the JSBMR.

Androgen deprivation therapy and aromatase inhibitors are known to cause a decrease in bone mineral density and an increase in fractures. Patients receiving these treatments have been shown to have a fracture risk equal to or greater than that of patients with osteoporosis with prevalent fractures. This manual was created to prevent fractures in patients with cancer treatment-induced bone loss with high fracture risks who cannot be treated under the current Japanese guideline for the prevention and treatment of osteoporosis. This manual recommends drug treatment for patients with BMD - 2.0 ≤ T score < - 1.5 with the family history of hip fracture or 15% or more 10-year probability of major osteoporotic fractures by FRAX®; or in patients with BMD T score < - 2.0. It is important to verify whether the use of this manual can reduce fractures and improve the quality of life of patients with cancer treatment-induced bone loss by prospective studies.

Circulating FGF23 is not associated with cardiac dysfunction, atherosclerosis, infection or inflammation in hemodialysis patients.

Fibroblast growth factor (FGF) 23 is a bone-derived hormone regulating serum inorganic phosphate (Pi) concentration. FGF23 is also involved in the development of chronic kidney disease (CKD)-mineral and bone disorder. Serum FGF23 concentration begins to increase early in the progression of CKD and can be remarkably high in hemodialysis patients with end-stage renal disease. It has been reported that high FGF23 concentration is a risk factor for cardiac dysfunction, atherosclerosis, infection or systemic inflammation in CKD patients. FGF23 was also shown to induce cardiac hypertrophy directly acting on cardiomyocytes. However, it is still controversial whether high FGF23 is causing cardiac dysfunction, atherosclerosis, infection or systemic inflammation in CKD patients. In the current study, we investigated whether FGF23 concentration is associated with cardiac dysfunction, atherosclerosis, infection or systemic inflammation in Japanese hemodialysis patients. We recruited 119 hemodialysis patients and examined the association between serum FGF23 concentration and several parameters concerning mineral metabolism, cardiac dysfunction, atherosclerosis, infection, and systemic inflammation. Serum FGF23 concentration was independently associated with serum calcium and Pi concentration (ß = 0.276, p < 0.001; ß = 0.689, p < 0.001). However, serum FGF23 concentration was not associated with parameters of cardiac dysfunction, atherosclerosis, infection, and systemic inflammation, either. Our results do not support the hypothesis that high FGF23 in dialysis patients is the cause of cardiac dysfunction, atherosclerosis, infection or systemic inflammation.

On the origin of the optical and near-infrared extragalactic background light.

In optical and near-infrared background light, excess brightness and fluctuation over the known backgrounds have been reported. To delineate their origin, a fluctuation analysis of the deepest optical images was performed, leading to the detection of a flat fluctuation down to 0.2 arcsec, which is much larger than that expected for galaxies. The sky brightness obtained from the detected fluctuation is a few-times brighter than the integrated light of the galaxies. These findings require some new objects. As a candidate, faint compact objects (FCOs) whose surface number density rapidly increases to the faint end were proposed. FCOs are very compact and show peculiar spectra with infrared excess. If FCOs cause the excess brightness and fluctuation, the surface number density reaches 2.6 × 103 arcsec-2. γ-ray observations require the redshift of FCOs to be less than 0.1 with FCOs consisting of missing baryons. A very low M/L indicates that FCOs are powered by gravitational energy associated with black holes.