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ABSTRACT Associations between urinary pentosidine, one of the advanced glycation end products in collagen, and the risk of fracture in patients with severe osteoporosis are unknown. In this study, we investigated whether the urinary pentosidine level is associated with the incidence of morphometric vertebral fracture and nonvertebral fracture using data of a randomized, controlled trial, JOINT‐05. JOINT‐05 enrolled Japanese women aged 75 years or older with primary osteoporosis. Patients were randomly assigned (1:1) to receive sequential therapy (teriparatide followed by alendronate) or monotherapy with alendronate for 120 weeks. Incidences of vertebral and nonvertebral fractures were assessed morphologically. During treatment, urinary levels of pentosidine and serum levels of bone turnover markers (osteocalcin, procollagen type I amino‐terminal propeptide, and tartrate‐resistant acid phosphatase 5b) were measured. A total of 967 patients with baseline pentosidine levels were included in the study. Of these, 137 had vertebral fractures, and 42 had nonvertebral fractures. The rate ratios for vertebral fracture for the second (30–39 pmol/mL), third (40–49 pmol/mL), and fourth quartile (≥50 pmol/mL) groups divided by pentosidine level compared with the first quartile (

Objectives: To assess differences in efficacy of a 28.2-μg teriparatide formulation for twice-weekly use (2/W-TPTD) by patient characteristics. Methods: A post hoc analysis was performed using data from a multicenter, randomized, double-blind, double-dummy, non-inferiority trial (TWICE study) conducted in Japan comparing the efficacies of once-weekly and twice-weekly injections of teriparatide (TPTD). Specifically, a stratified analysis of percentage changes from baseline was performed using the final data on lumbar spine bone mineral density (BMD) after a 48-week treatment period (n = 251, 2/W-TPTD; n = 239, a 56.5-μg teriparatide formulation for once-weekly use [1/W-TPTD]). Results: Across all subgroups defined by patient characteristics that included 9 or more subjects, the lumbar spine BMD increased significantly in both groups. In the 2/W-TPTD group, the percentage change was significantly higher in subjects with no non-vertebral fractures without large external force occurring at or after age 50 years versus those with such fractures. The lower the stratification in baseline lumbar spine BMD, total hip BMD, or femoral neck BMD, the greater was the percentage change. Conclusions: Whereas all subgroups can expect a significant improvement in lumbar spine BMD, there were some patient characteristics that affected the percentage increase in BMD.

Objectives: On July 20, 2012, the European Medicines Agency (EMA) provided a recommendation that limits the long-term use of calcitonin. Based on this recommendation, we investigate the presence or absence of a cancer diagnosis in subjects who participated in the ongoing clinical trial of elcatonin. Methods: When the EMA gave this recommendation, we were conducting “a 3-year placebo-controlled clinical study for elcatonin” (hereinafter, referred to as “the original study”). In accordance with the recommendation of EMA, we performed an intermediate analysis on the subjects of the original study to assess whether the study could be safely continued. We also added a 2-year follow-up study to investigate the risk of carcinogenesis for 5 years from the start of administration. We compared the risk of carcinogenesis estimated by person-year method in elcatonin group with that in placebo group. Results: In the original study, there were 433 subjects in the elcatonin group and 437 in the placebo group, of whom 322 and 323, respectively, agreed to participate in the additional follow-up study. The average cancer incidence rate per 100 person-years 5 years from the start of administration was 1.02 in the elcatonin group and 1.08 in the placebo group, respectively, and there was no clear difference. Conclusions: Since the number of cases in this study was small, we cannot completely deny the cancer risk due to long-term administration of this drug. However, the results do not suggest that once-weekly administration of 20 units of elcatonin increases the carcinogenic risk. Keywords: Calcitonin, Elcatonin, Once-weekly injection, Osteoporosis, Cancer risk

Abstract Background Immune checkpoint inhibitors including nivolumab, an anti-programmed cell death protein 1 antibody, are recently developed cancer immunotherapy agents. Immune checkpoint inhibitors are known to cause autoimmune-related side effects including endocrine dysfunctions. However, there are few reports on late-onset isolated adrenocorticotropic hormone (ACTH) deficiency caused by nivolumab. Case presentation The patient was a 72-year-old female. When she was 64 years old, she was diagnosed with malignant melanoma of the left thigh accompanied by left inguinal lymph node metastases, and she received several courses of chemotherapy for malignant melanoma followed by the resection of these lesions. At 71 years of age, multiple metastases were found and treatment with nivolumab 2 mg/kg every 3 weeks was initiated. Six months later, replacement with levothyroxine was started because of hypothyroidism following mild transient thyrotoxicosis. Eleven months after the beginning of nivolumab, the treatment was discontinued because of tumor expansion. Four months after the discontinuation of nivolumab, general malaise and appetite loss worsened, and 2 months later, hyponatremia (Na; 120–127 mEq/L) and hypoglycemia (fasting plasma glucose; 62 mg/dL) appeared. Her ACTH and cortisol levels were extremely low (ACTH; 9.6 pg/mL, cortisol; undetectable). Challenge tests for anterior pituitary hormones showed that responses of ACTH and cortisol secretion to corticotropin-releasing hormone were disappeared, although responses of other anterior pituitary hormones were preserved. Thus, she was diagnosed with isolated ACTH deficiency. Her symptoms were improved after treatment with hydrocortisone. Conclusions The present report showed a case of late-onset isolated ACTH deficiency accompanied by hyponatremia, which was diagnosed 6 months after the discontinuation of nivolumab. The effects of nivolumab last for a long time and the side effects of nivolumab can also appear several months after discontinuation of the drug. Repeated monitoring of serum sodium levels may be a beneficial strategy to find the unexpected development of adrenal insufficiency even after discontinuation of nivolumab.

Abstract Background The thyroid gland is resistant to microbial infection, because of its organ characteristics such as encapsulation, iodine content, and rich blood supply. Therefore, acute suppurative thyroiditis (AST), as a bacterial infection of the thyroid gland, is rarely seen. AST typically takes places on the left side the neck region in children, because of the coincidence of the left piriform sinus fistula, as a most common route of infection. AST is also usually seen in immunocompromised hosts. Herein, we report a rare case of AST in the right thyroid lobe of adult woman without any immunocompromised condition. Case presentation A 59-year-old woman was introduced to our hospital for the further examination with fever, sore throat, and right anterior neck swelling. The patient appeared not to be immunodeficient. Neck ultrasonography showed a 47-mm, hypoechoic, heterogeneous nodule with ill-defined margins and irregular form, suggesting a right thyroid malignant nodule. Fine needle aspiration (FNA) biopsy specimen revealed numerous number of neutrophils in the background without nuclear atypia. Based on the clinical course and cytology, AST was confirmed to be diagnosed. Complete response was obtained by an intravenous administration of antimicrobial agents within a week. Image findings such as CT scan did not show any piriform sinus fistula. Four months later, neck ultrasonography showed a significant decrease in size of the nodule in the right thyroid gland to 27 mm, but the lesion still resembled a malignant nodule. So, FNA was repeated again and cytological examination confirmed papillary thyroid carcinoma (PTC). The patient subsequently underwent total thyroidectomy and bilateral level D1 lymph node dissection. Histological findings revealed a 20-mm PTC in the right lobe with sternothyroid muscle invasion of the tumor. Conclusions This report represents a rare case of AST associated with PTC on the right side of thyroid gland, found in a healthy adult woman. The reason why AST coincided with malignant thyroid tumor is unclear. We have to take it into our account that malignant tumor may exist in the background when AST is identified on the right side of thyroid gland with a healthy subject.

Background: Patients with type 2 diabetes mellitus (T2DM) have an increased risk of muscle mass reduction. However, the association between muscle mass and mortality in T2DM remains unknown. Methods: This was a historical cohort study with the endpoint of all-cause mortality. This study included 163 Japanese men and 141 postmenopausal women with T2DM whose body compositions were evaluated using dual-energy X-ray absorptiometry. Low muscle mass was defined as a skeletal muscle mass index (SMI) of

BackgroundAn assessment of bone strength based on bone mineral density (BMD) underestimates the risk of fracture in patients with diabetes mellitus (T2DM). However, using the trabecular bone score (TBS) for estimating bone microarchitecture, previous studies showed that bone fragility is associated with deterioration of the microstructure concomitantly with decreased BMD. This study was conducted to clarify which of these skeletal-related factors had a more prominent relationship with bone fragility.Research design and methodsA retrospective cross-sectional study was performed at Shimane University Hospital. A total of 548 Japanese patients with T2DM [257 postmenopausal women and 291 men aged over 50 years] were included. TBS of the spine was computed from dual-energy X-ray absorptiometry images obtained from BMD measurements.ResultsVertebral fractures (VFs) were identified in 74 (28.8%) women and 115 (39.5%) men. A relationship between BMD and VFs was observed in the limited subgroup of women with a BMD T-score ≤-1.0. According to multivariate logistic regression analysis, low TBS was significantly correlated with prevalent VFs, independent of BMD in both genders, except for men with a BMD T-score > -1.0. The decision tree showed that the priority factor for determining VFs was TBS, not BMD.ConclusionSpinal microarchitecture represented by TBS was a more dominant skeletal factor for bone fragility than the decrease in bone mass, independent of BMD, in patients with T2DM. This observation suggests that loss of structural bone quality was crucial underlying pathogenesis for bone brittleness in these populations, regardless of gender. An integrated assessment of bone strength by BMD and TBS would help diagnose diabetic osteoporosis.

OBJECTIVE:Previous studies suggest that the presence of diabetic peripheral polyneuropathy (DPN) is associated with atherosclerotic diseases; however, little is known about the relationship between diabetic nerve conduction velocity (NCV) versus arterial stiffness and atherosclerosis parameters. METHODS:The subjects in this study were 292 men with type 2 diabetes mellitus (T2DM). All subjects underwent NCV examination at median and tibial nerves as motor nerve (MCV) as well as median and sural nerves as sensory nerve (SCV). Brachial-ankle pulse wave velocity (baPWV) and carotid intima-media thickness (IMT) were evaluated as arterial stiffness and atherosclerosis parameters. RESULTS:Pearson's correlation coefficient showed that NCV at all sites negatively correlated with baPWV, maximal and mean IMT (IMT-Max and IMT-Mean), and plaque score (all p values p

PURPOSE:Hypertension is a risk factor of atherosclerotic diseases. However, the importance of prehypertension in Japanese patients with type 2 diabetes mellitus (T2DM) is controversial. The aim of this study was to examine association between prehypertension, hypertension and atherosclerosis in T2DM. METHODS:We recruited 179 Japanese patients with T2DM, who never took any medication for diabetes, hypertension, dyslipidemia, or atherosclerosis. Intima-media thickness (IMT) of common carotid artery was evaluated by high-resolution B-mode ultrasonography. RESULTS:Multiple regression analysis adjusted for age, duration of diabetes, body mass index, HbA1c, fasting C-peptide, triglyceride, HDL-cholesterol, LDL-cholesterol, and estimated glomerular filtration rate showed that systolic blood pressure (SBP), but not diastolic BP, was significantly and positively associated with maximum IMT (IMT-max), mean IMT, and plaque score (β = 0.28, p140 mmHg). Multiple logistic regression analysis adjusted for the variables described above plus gender and smoking showed that prehypertension and hypertension were significantly associated with the increased risk of atherosclerosis [prehypertension; odds ratio (OR) 3.45, 95% confidence interval (CI) 1.11-10.76, p = 0.033, and hypertension; OR 7.29, 95%CI 1.99-26.78, p = 0.003]. CONCLUSION:These findings suggest that prehypertension categorized by SBP is an important risk factor of atherosclerosis independently of conventional risk factors in patients with T2DM.

Bone fragility is increased in patients with type 2 diabetes mellitus (T2DM), but a useful method to estimate bone fragility in T2DM patients is lacking because bone mineral density alone is not sufficient to assess the risk of fracture. This study investigated the association between prevalent vertebral fractures (VFs) and the vertebral strength index estimated by the quantitative computed tomography-based nonlinear finite element method (QCT-based nonlinear FEM) using multi-detector computed tomography (MDCT) for clinical practice use.A cross-sectional observational study was conducted on 54 postmenopausal women and 92 men over 50 years of age, all of whom had T2DM. The vertebral strength index was compared in patients with and without VFs confirmed by spinal radiographs. A standard FEM procedure was performed with the application of known parameters for the bone material properties obtained from nondiabetic subjects.A total of 20 women (37.0%) and 39 men (42.4%) with VFs were identified. The vertebral strength index was significantly higher in the men than in the women (P

The second messenger signaling of the parathyroid hormone (PTH) and PTH-related peptide (PTHRP)- induced osteoclast-like cell structure in mouse hemopoietic blast cells with PTH binding sites was studied. cAMP analogues and two different varieties of protein kinase C (PKC) inhibitors, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine dihydrochloride (H-7) and staurosporine. Evidence to prove that protein kinase and PKC are involved in the activation of osteoclast-like cell development by PTH and PTHRP was obtained.

Osteoporosis and sarcopenia are common comorbid diseases, yet their shared mechanisms are largely unknown. We found that genetic variation near FAM210A was associated, through large genome-wide association studies, with fracture, bone mineral density (BMD), and appendicular and whole body lean mass, in humans. In mice, Fam210a was expressed in muscle mitochondria and cytoplasm, as well as in heart and brain, but not in bone. Grip strength and limb lean mass were reduced in tamoxifen-inducible Fam210a homozygous global knockout mice (TFam210a-/-), and in tamoxifen-inducible Fam210 skeletal muscle cell-specific knockout mice (TFam210aMus-/-). Decreased BMD, bone biomechanical strength, and bone formation, and elevated osteoclast activity with microarchitectural deterioration of trabecular and cortical bones, were observed in TFam210a-/- mice. BMD of male TFam210aMus-/- mice was also reduced, and osteoclast numbers and surface in TFam210aMus-/- mice increased. Microarray analysis of muscle cells from TFam210aMus-/- mice identified candidate musculoskeletal modulators. FAM210A, a novel gene, therefore has a crucial role in regulating bone structure and function, and may impact osteoporosis through a biological pathway involving muscle as well as through other mechanisms. [ABSTRACT FROM AUTHOR]

Bone and glucose metabolism are closely associated with each other. Both osteoblast and osteoclast functions are important for the action of osteocalcin, which plays pivotal roles as an endocrine hormone regulating glucose metabolism. However, it is unknown whether osteocytes are involved in the interaction between bone and glucose metabolism. We used MLO-Y4-A2, a murine long bone-derived osteocytic cell line, to investigate effects of glucose uptake inhibition on expressions of osteocalcin and bone-remodeling modulators in osteocytes. We found that glucose transporter 1 (GLUT1) is expressed in MLO-Y4-A2 cells and that treatment with phloretin, a GLUT inhibitor, significantly inhibited glucose uptake. Real-time PCR and Western blot showed that phloretin significantly and dose-dependently decreased the expressions of RANKL and osteocalcin, whereas osteoprotegerin or sclerostin was not affected. Moreover, phloretin activated AMP-activated protein kinase (AMPK), an intracellular energy sensor. Coincubation of ara-A, an AMPK inhibitor, with phloretin canceled the phloretin-induced decrease in osteocalcin expression, but not RANKL. In contrast, phloretin suppressed phosphorylation of ERK1/2, JNK, and p38 MAPK, and treatments with the p38 inhibitor SB203580 and the MEK inhibitor PD98059, but not the JNK inhibitor SP600125, significantly decreased expressions of RANKL and osteocalcin. These results indicate that glucose uptake by GLUT1 is required for RANKL and osteocalcin expressions in osteocytes, and that inhibition of glucose uptake decreases their expressions through AMPK, ERK1/2, and p38 MAPK pathways. These findings suggest that lowering glucose uptake into osteocytes may contribute to maintain blood glucose levels by decreasing osteocalcin expression and RANKL-induced bone resorption. [ABSTRACT FROM AUTHOR]

Background: The clinical effect of bisphosphonate treatment has not been clearly evaluated by kidney function in Japanese Chronic Kidney Disease (CKD) patients with osteoporosis. This study analyzed the data from three risedronate Japanese phase III trials. The clinical effect of risedronate therapy was evaluated in CKD patients with osteoporosis.Methods: The Japanese clinical trials involved 852 subjects who received risedronate (2.5 mg once daily or 17.5 mg once weekly) and whose estimated glomerular filtration rate (eGFR) were calculable and at ≥ 30 mL/min. The subjects were divided into subgroups according to the eGFR level: ≥ 90 mL/min/1.73 m2, ≥ 60 to < 90 mL/min/1.73 m2, ≥ 30 to < 60 mL/min/1.73 m2. Lumbar spine bone mineral density (BMD), bone turnover markers (BTMs) and adverse events were evaluated at 48 weeks.Results: Adverse event incidence was similar among three subgroups. There was also no exacerbation of impaired kidney function associated with risedronate administration in the subjects with eGFR above 30 mL/min/1.73 m2. Risedronate administration induced a significant increase in lumbar spine BMD and significant inhibition of BTMs in three subgroups.Conclusions: The risedronate therapy showed similar clinical effects in CKD patients with osteoporosis compared to those without CKD. [ABSTRACT FROM AUTHOR]

Background: Growth hormone deficiency (GHD) is associated with non-alcoholic fatty liver disease (NAFLD). A recent animal study showed that hepatocyte-specific receptor activator of nuclear factor-kappa B (RANK) knockout mice had significantly lower liver fat content compared with control mice concomitant with a decrease in production of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) from hepatocytes and kupffer cells. The role of anti-RANK ligand (RANKL) antibody for osteoporosis on hepatitis in patients with aGHD is still unknown. Case presentation: A forty-seven-year-old female patient was referred to our hospital to investigate chronic hepatitis caused by unknown etiology. She had past history of craniopharyngioma treated with craniotomy and post-surgical radiotherapy. She was for the first time diagnosed as panhypopituitarism including growth hormone deficiency and osteoporosis by endocrine examinations and bone mineral densitometry, respectively. In addition, non-alcoholic steatohepatitis (NASH) was histologically confirmed by liver biopsy in this time. Sixty mg anti-RANKL antibody, which was subcutaneously injected to treat the osteoporosis every six months after replacement of 5 mg hydrocortisone and 30 µg oral desmopressin, rapidly decreased the levels of her liver enzymes (ALT and ?GTP were 133 to 72 U/L and 284 to 99 U/L at 16 months after the beginning of the treatment, respectively). Additional amelioration of liver dysfunction was not observed after growth hormone replacement. Conclusions: The clinical course of the present case suggested that RANKL-RANK signaling may be a key pathological mechanism in establishment or development of NAFLD or NASH in patients with panhypopituitarism including GHD. [ABSTRACT FROM AUTHOR]

Vascular calcification, especially medial artery calcification, is associated with cardiovascular death in patients with diabetes mellitus and chronic kidney disease (CKD). To determine the underlying mechanism of vascular calcification, we have demonstrated in our previous report that advanced glycation end-products (AGEs) stimulated calcium deposition in vascular smooth muscle cells (VSMCs) through excessive oxidative stress and phenotypic transition into osteoblastic cells. Since AGEs can induce apoptosis, in this study we investigated its role on VSMC apoptosis, focusing mainly on the underlying mechanisms. A rat VSMC line (A7r5) was cultured, and treated with glycolaldehyde-derived AGE-bovine serum albumin (AGE3-BSA). Apoptotic cells were identified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. To quantify apoptosis, an enzyme-linked immunosorbent assay (ELISA) for histone-complexed DNA fragments was employed. Real-time PCR was performed to determine the mRNA levels. Treatment of A7r5 cells with AGE3-BSA from 100 μg/mL concentration markedly increased apoptosis, which was suppressed by Nox inhibitors. AGE3-BSA significantly increased the mRNA expression of NAD(P)H oxidase components including Nox4 and p22phox, and these findings were confirmed by protein levels using immunofluorescence. Dihydroethidisum assay showed that compared with cBSA, AGE3-BSA increased reactive oxygen species level in A7r5 cells. Furthermore, AGE3-induced apoptosis was significantly inhibited by siRNA-mediated knockdown of Nox4 or p22phox. Double knockdown of Nox4 and p22phox showed a similar inhibitory effect on apoptosis as single gene silencing. Thus, our results demonstrated that NAD(P)H oxidase-derived oxidative stress are involved in AGEs-induced apoptosis of VSMCs. These findings might be important to understand the pathogenesis of vascular calcification in diabetes and CKD. [ABSTRACT FROM AUTHOR]

Abstract  Cinacalcet, an allosteric modulator of a calcium (Ca)-sensing receptor, significantly suppresses parathyroid hormone (PTH) secretion and bone turnover rate in chronic hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT). In this study, bone metabolism after cinacalcet treatment was examined, because hungry bone syndrome is sometimes experienced after parathyroidectomy in severe SHPT. We conducted a prospective observational study in 17 HD patients with SHPT. Cinacalcet was started at 25 mg/day, and the dose was increased step by step based on serum calcium level. A significant decrease in serum Ca and intact PTH concentration was found within 2 weeks. Tartrate-resistant acid phosphatase 5b, a good bone resorption marker, was significantly decreased at week 2 of the study. Serum bone alkaline phosphatase, a marker of bone formation, was increased at week 2 compared with the basal level. It became, however, gradually decreased until week 14. Only one patient whose bone turnover was considerably high had a mild numbness feeling. These results suggest that cinacalcet treatment might transiently accelerate bone formation with rapid suppression of bone resorption. This uncoupling could be involved in a mechanism by which cinacalcet decreases serum Ca level. [ABSTRACT FROM AUTHOR]

Abstract  Bisphosphonate is an effective drug to reduce fracture risk in osteoporotic patients; however, factors affecting the efficacy of bisphosphonate treatment are not fully known, especially in Japanese patients. In the present study, we examined the relationships between an increase in lumbar spine bone mineral density (BMD) by bisphosphonates and several pretreatment parameters, including biochemical, bone/mineral, and body composition indices, in 85 postmenopausal osteoporotic patients treated with alendronate or risedronate. BMD increase was measured by dual-energy X-ray absorptiometry at the lumbar spine before and 2 years after treatment. BMD increase at the lumbar spine was observed as independent of age, height, weight, body mass index, and fat mass, although lean body mass seemed slightly related. On the other hand, fasting plasma glucose (FPG) levels were significantly and positively related to BMD increase at the lumbar spine. In multiple regression analysis, FPG levels were not significantly related to BMD increase at the lumbar spine when lean body mass was considered. As for bone/mineral parameters, BMD increase at the lumbar spine was not significantly related to serum levels of calcium, parathyroid hormone (PTH), and alkaline phosphatase or urinary levels of deoxypiridinoline and calcium excretion. As for BMD parameters, Z-scores of BMD at any site and bone geometry parameters obtained by forearm peripheral quantitative computed tomography were not significantly related to BMD increase at the lumbar spine. BMD increases at the lumbar spine were similar between groups with or without vertebral fractures. In conclusion, BMD increase at the lumbar spine by bisphosphonate treatment was not related to any pretreatment parameters, including body size, body composition, and bone/mineral metabolism in postmenopausal Japanese women with primary osteoporosis, although FPG correlated partly to BMD through lean body mass. [ABSTRACT FROM AUTHOR]

Abstract  Glucocorticoid (GC) therapy induces rapid bone loss, but the early changes in calcium and bone metabolism in patients treated with GC have not been clarified. To investigate the changes in calcium and bone metabolism during the early stage of GC therapy, we analyzed various biochemical markers of bone metabolism. The serum levels of calcium (Ca), phosphorus, parathyroid hormone (PTH), osteocalcin (OC), bone alkaline phosphatase (BAP), and type I collagen cross-linked N-telopeptide (NTx), as well as the urinary levels of Ca, creatinine, and NTx, were measured on days 0, 3, 7, and 28 of GC therapy. The subjects were divided into the following four groups: 9 patients receiving pulse therapy (P), 18 patients receiving prednisolone (PSL) at doses ≥40 mg/day (H), 9 patients receiving PSL at doses ≥20 mg/day (M), and 11 patients receiving PSL at doses ≤10 mg/day (S). The serum OC level showed a marked decrease on day 3 of GC therapy (−41.2% ± 6.6%, P P P [ABSTRACT FROM AUTHOR]

In some patients with multiple endocrine neoplasiatype 1 (MEN1) it is not possible to identify a germlinemutation in the MEN1 gene. We sought to documentthe loss of expression and function of the MEN1 geneproduct, menin, in the tumors of such a patient. Theproband is an elderly female patient with primaryhyperparathyroidism, pancreatic islet tumor, and breastcancer. Her son has primary hyperparathyroidism. Nogermline MEN1 mutation was identified in the probandor her son. However, loss of heterozygosity at theMEN1 locus and complete lack of menin expressionwere demonstrated in the proband's tumor tissue. Theproband's cultured parathyroid cells lacked the normalreduction in proliferation and parathyroid hormonesecretion in response to transforming growth factor-β. This assessment provided insight into the molecularpathogenesis of the patient and provides evidence fora critical requirement for menin in the antiproliferativeaction of transforming growth factor-β. [ABSTRACT FROM AUTHOR]

Glucocorticoid (GC)-induced osteoporosis (GIO) is frequently seen in patients with excessive GC. Numerous questions remain to be clarified about the pathogenesis and treatment of GIO, and the mechanism of GC-inhibited bone formation is not well known. Several studies suggest that parathyroid hormone (PTH) and hormone replacement therapy are effective for GIO. We therefore investigated whether PTH and estrogen would affect cell proliferation and alkaline phosphatase (ALP) activity inhibited by dexamethasone (Dex) in mouse osteoblastic cell-line MC3T3-E1 cells. Low-dose (10−11M) PTH as well as 10−8M 17-β-estradiol (17β-E2) significantly attenuated Dex-inhibited ALP activity, although 10−8M PTH did not affect it. ICI 182780 (10−8M) antagonized the effects of 17β-E2 on Dex-suppressed ALP activity. Neutralizing anti-IGF-I antibody (3µg/ml) blocked the reverse effects of 17β-E2 on ALP activity suppressed by Dex. PTH (10−11M), but not 17β-E2, significantly attenuated [3H]thymidine incorporation inhibited by Dex. On the other hand, PTH and estrogen did not affect the level of 11-β-hydrosteroid dehydrogenase type I mRNA increased by Dex. In conclusion, the present study demonstrated that low-dose PTH and estrogen reversed Dex-inhibited ALP activity in the mouse osteoblastic cell-line. [ABSTRACT FROM AUTHOR]

It is well known that thyroid hormone excess causes bone loss. However, the precise mechanism of bone loss by thyroid hormone still remains unclear. When T3 was added to unfractionated bone cells after degeneration of pre‐existent osteoclasts, T3 (1 pM–100 nM) dose‐dependently stimulated osteoclast‐like cell formation, irrespective of the presence of indomethacin and IL‐6 Ab. T3 increased the expression of osteoprotegerin (OPG) messenger RNA (mRNA), but not of receptor activator of nuclear factor κB ligand (RANKL) in unfractionated bone cells, suggesting that the stimulatory effect of T3 on osteoclast formation was not mediated by the RANKL/OPG system. We next examined the direct effect of T3 on osteoclast precursors in the absence of osteoblasts, using hemopoietic blast cells derived from spleen cells. T3 (1 pM–100 nM) dose‐dependently stimulated osteoclast‐like cell formation from osteoclast precursors. OPG did not inhibit T3‐induced osteoclast formation from osteoclast precursor cells. The polymerase chain reaction (PCR) product corresponding in size to the mouse T3 receptor α1 cDNA was detected in osteoclast precursors from mouse hemopoietic blast cells as well as mouse heart and mouse osteoblastic cell line MC3T3‐E1 cells, suggesting that T3 directly stimulated osteoclast‐like cell formation from osteoclast precursors in the absence of osteoblasts. Further, T3 increased the expression of c‐Fos mRNA at 15 min and 24 h and Fra‐1 mRNA at 2 and 6 h in osteoclast precursors. Consistent with the increased expression of c‐Fos mRNA observed by RT‐PCR, the activation of c‐Fos occurred in osteoclast precursor cells stimulated by T3, while the activation of neither NF‐κB nor MAPKs was observed by immunoblot analysis. Antisense oligodeoxynucleotides (as‐ODN) complementary to c‐Fos mRNA at 1 μM significantly inhibited T3‐induced osteoclast‐like cell formation from osteoclast precursors in the absence of stromal cells while sense‐ODN did not affect T3‐induced osteoclast‐like cell formation. These results indicate that T3 directly stimulates osteoclast differentiation at least in part by up‐regulation of c‐fos protein in osteoclast precursor cells. J. Cell. Physiol. 201: 17–25, 2004. © 2004 Wiley‐Liss, Inc. [ABSTRACT FROM AUTHOR]

Although high inorganic phosphate (Pi) concentration in culture media directly inhibits generation of new osteoclasts and also inhibits bone resorption by mature osteoclasts, its precise mechanism and the physiological role have not been elucidated. The present study was performed to investigate these issues. Increase in extracellular Pi concentration ([Pi]e) (2.5–4 mM) concentration dependently inhibited 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] or parathyroid hormone (PTH)-(1-34)-induced osteoclast-like cell formation from unfractionated bone cells in the presence of stromal cells. Increase in [Pi]e (2.5–4 mM) concentration dependently inhibited 1,25(OH)2D3-, PTH-(1-34)-, or receptor activator of NF-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF)-induced osteoclast-like cell formation from hemopoietic blast cells in the absence of stromal cells. Increase in [Pi]e (2.5–4 mM) dose dependently stimulated the expression of osteoprotegerin (OPG) mRNA and increased the expression of OPG mRNA suppressed by PTH-(1-34) or 1,25(OH)2D3 in unfractionated bone cells, while it did not affect RANKL mRNA. Increase in [Pi]e (2.5-4 mM) concentration dependently inhibited the bone-resorbing activity of isolated rabbit osteoclasts. Increase in [Pi]e (4 mM) induced the apoptosis of isolated rabbit osteoclasts while it did not affect the apoptosis of osteoclast precursor cells and mouse macrophage-like cell line C7 cells that can differentiate into osteoclasts in the presence of RANKL and M-CSF. These results indicate that increase in [Pi]e inhibits osteoclast differentiation both by up-regulating OPG expression and by direct action on osteoclast precursor cells. It is also indicated that increase in [Pi]e inhibits osteoclastic activity at least in part by the direct induction of apoptosis of osteoclasts. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Background. A relatively high level of serum parathyroid hormone (PTH) is required to maintain normal bone turnover in patients with chronic kidney disease (CKD). ‘Uraemic toxins’ could cause an impaired response to PTH in bone and result in low turnover bone disease. Since phenylacetic acid (PAA) has been identified as one of the uraemic toxins in patients with CKD and has an inhibiting property of monocyte function, we examined if PAA might inhibit osteoblastic functions in vitro. Methods. Using mouse osteoblastic MC3T3-E1 cells, we performed BrdU incorporation, real-time PCR, Western blot and stainings to see the effect of PAA. Results. PAA significantly inhibited proliferation in a dose-dependent manner ranging between 0.5 and 5 mM. PAA reduced osteocalcin mRNA level, alkaline phosphatase activity and osteoblastic mineralization. PAA pre-treatment also decreased both PTH-induced cAMP production and extracellular signal-regulated kinase (ERK) phosphorylation. Conclusion. PAA, a newly identified uraemic toxin, affects osteoblastic functions such as proliferation, differentiation, mineralization and responsiveness to PTH, indicating that this molecule could play an important role in the pathogenesis of low turnover bone in CKD. [ABSTRACT FROM AUTHOR]

Objective: Undercarboxylated osteocalcin (ucOC) produced from the bone was recently found to play a regulatory role in the insulin and adiponectin secretion. We performed a cross-sectional study to investigate the relationship between ucOC and diabetes mellitus (DM).Methods: We included 1,870 subjects aged over 50 from participants of a health examination. According to the current medication and past history, 605 subjects had hypertension (HT), 316 had dyslipidemia (DL), and 182 had type 2 DM. Fasting blood samples were collected to measure concentrations of ucOC and the bone turnover marker, tartrate-resistant acid phosphatase 5b (TRACP5b) by ELISA.Results: The serum ucOC level was significantly lower in DM(+) than DM(-) in both men and women. In a logistic regression analysis, a low level of ucOC was significantly associated with the presence of DM in both men and women after adjusting for age, BMI, serum creatinine, triglyceride, and TRACP5b. Multiple regression analysis showed a negative association of ucOC with HbA1c and fasting plasma glucose, and a positive association with the insulin level. In contrast, no association was found between TRACP5b and the indices above, suggesting that the effect of ucOC on the insulin secretion and the glycemic status was independent of bone turnover.Conclusions: The present cross-sectional study showed a significant association between ucOC and glucose metabolism after correction with bone turnover in a community-dwelling population both in men and women, indicating that ucOC may play an important role in the pathogenesis of DM through the pathways independent of bone metabolism. [ABSTRACT FROM AUTHOR]

Internal tandem duplication mutations in the Flt3 gene (ITD-FLT3) enhance cell migration toward the chemokine Cxcl12, which is highly expressed in the therapy-protective bone marrow niche, providing a potential mechanism underlying the poor prognosis of ITD-FLT3+ acute myeloid leukemia. We aimed to investigate the mechanisms linking ITD-FLT3 to increased cell migration toward Cxcl12. Classification of the expression of Cxcl12-regulated genes in ITD-FLT3+ cells demonstrated that the enhanced migration of ITD-FLT3+ cells toward Cxcl12 was associated with the differential expression of genes downstream of Cxcl12/Cxcr4, which are functionally distinct from those expressed in ITD-FLT3- cells but are independent of the Cxcr4 expression levels. Among these differentially regulated genes, the expression of Rock1 in the ITD-FLT3+ cells that migrated toward Cxcl12 was significantly higher than in ITD-FLT3- cells that migrated toward Cxcl12. In ITD-FLT3- cells, Rock1 expression and Mypt1 phosphorylation were transiently up-regulated but were subsequently down-regulated by Cxcl12. In contrast, the presence of ITD-FLT3 blocked the Cxcl12-induced down-regulation of Rock1 and early Mypt1 dephosphorylation. Likewise, the FLT3 ligand counteracted the Cxcl12-induced down-regulation of Rock1 in ITD-FLT3- cells, which coincided with enhanced cell migration toward Cxcl12. Rock1 antagonists or Rock1 shRNA abolished the enhanced migration of ITD-FLT3+ cells toward Cxcl12. Our findings demonstrate that ITD-FLT3 increases cell migration toward Cxcl12 by antagonizing the down-regulation of Rock1 expression. These findings suggest that the aberrant modulation of Rock1 expression and activity induced by ITD-FLT3 may enhance acute myeloid leukemia cell chemotaxis to the therapy-protective bone marrow niche, where Cxcl12 is abundantly expressed. [ABSTRACT FROM AUTHOR]

Vitamin D deficiency and advanced glycation end products (AGEs) are suggested to be involved in the pathogenesis of osteoporosis and sarcopenia. However, the effects of vitamin D and AGEs on myogenesis and the interaction between muscle and bone remains still unclear. We previously showed that osteoglycin (OGN) is secreted from myoblasts and stimulates osteoblastic differentiation, suggesting that it plays important roles in the interaction between muscle and bone. The aim of this study is thus to examine the effects of vitamin D and AGEs on myoblastic differentiation of C2C12 cells and osteoblastic differentiation of osteoblastic MC3T3-E1 cells through OGN expression. 1α,25-dihydroxyvitamin D3 (1,25D) and eldecalcitol, an active vitamin D analog, induced the expression of MyoD, myogenin and OGN, and these effects were abolished by vitamin D receptor (VDR) suppression by siRNA in C2C12 cells. Moreover, conditioned medium from 1,25D-pretreated C2C12 cells stimulated the expression of type 1 collagen and alkaline phosphatase in MC3T3-E1 cells, compared to control medium from 1,25D-untreated C2C12 cells. In contrast, conditioned medium from VDR-suppressed and 1,25D-pretreated C2C12 cells showed no effects. AGE2 and AGE3 suppressed the expression of MyoD, myogenin and OGN in C2C12 cells. Moreover, 1,25D blunted the AGEs' effects. In conclusion, these findings showed for the first time that active vitamin D plays important roles in myogenesis and muscle-induced osteoblastogenesis through OGN expression. Active vitamin D treatment may rescue the AGEs-induced sarcopenia as well as - suppressed osteoblastic differentiation via OGN expression in myoblasts. [ABSTRACT FROM AUTHOR]

Background: Deteriorated quality of life (QOL) is a major problem in osteoporotic women. However, little is known regarding the determinants of QOL in patients with osteoporosis. Objective: Our aim was to explore the role of vitamin D status on QOL score in osteoporosis with high fracture risk. Methods: Patients were osteoporotic women aged ≥70 years and with ≥1 risk factor for incident fracture, namely prevalent osteoporotic fracture, bone mineral density (BMD) >–3.0 SD of young adult mean, or high bone turnover marker. Health-related QOL was assessed using the Japanese Osteoporosis Quality of Life Questionnaire (JOQOL). When patients were classified into quartiles by total QOL score). Serum 25-hydroxyvitamin D (25[OH]D) level was measured by immunoassay. Results: A total of 1585 osteoporotic women were included in the study (age range, 70–95 years). Age, body mass index, serum 25(OH)D status (low, normal, or high), bone mineral density, number of prevalent vertebral fractures, presence of hypertension, presence of osteoarthritis, and history of falls were significantly correlated with QOL quartile. Multivariate liner regression analysis indicated that low serum 25(OH)D level (<20 ng/mL) was an independent determinant of total QOL score quartile (P = 0.0055). The conventional determinants of QOL—age (P < 0.0001), body mass index (P = 0.0060), number of prevalent vertebral fractures (P < 0.0001), presence of osteoarthritis (P = 0.0074), and history of fall (P = 0.0098)—were also independent determinants of total QOL score. Conclusions: These results strongly suggest that low serum 25(OH)D level was a significant determinant of QOL in these osteoporotic women, independently of the conventional factors that reduce QOL. Maintenance of serum 25(OH)D levels >20 ng/mL may be required to maintain patients’ QOL in osteoporosis. [ABSTRACT FROM AUTHOR]