bluuebunny/crossref_metadata_2025 huggingface dataset:
Age of Attainment of Peak Bone Mass Is Site Specific in Swedish Men—The GOOD Study
Authors: Lorentzon Mattias , Mellström Dan , Ohlsson Claes
Published: April 2006

Results from this study suggest that PBM has been attained in the spine and femoral neck, but not in the radius or tibia, in 18- to 20-year-old men, in which an endosteal contraction and increase in cortical volumetric BMD is observed.

Introduction: Peak bone mass (PBM) is an important determinant for the risk of osteoporosis. In men, the age of attainment of PBM has been under some controversy. The objective of this study was to determine if peak bone mass had been attained, and whether it is site specific, in 18- to 20-year-old Swedish men.

Materials and Methods: The Gothenburg Osteoporosis and Obesity Determinants (GOOD) Study consists of 1068 men, 18.9 ± 0.6 years of age. BMD was measured using both DXA and pQCT. Environmental factors, such as dietary intake and physical activity, were assessed through questionnaires. The independent predictors of BMD were assessed through multiple linear regression, including age, height, weight, calcium intake, smoking, and physical activity.

Results and Conclusions: We show, in a large well-characterized cohort, that age was not an independent predictor of BMD of the lumbar spine, femoral neck, or total body, indicating that peak BMD has been achieved in these skeletal sites, whereas it was an independent predictor of BMD of the radius, suggesting that peak BMD has not yet been attained in the long bones. pQCT analyses of the radius and the tibia revealed that age was associated with cortical volumetric BMD and endosteal contraction of the radius and tibia. These results show that the age of attainment of PBM is site specific.
Ras-Association Domain Family 1 Protein, RASSF1C, Is an IGFBP-5 Binding Partner and a Potential Regulator of Osteoblast Cell Proliferation
Authors: Amaar Yousef G , Baylink David J , Mohan Subburaman
Published: April 2006

The goal of this study was to identify downstream signaling molecules involved in mediating the IGF-independent effects of IGFBP-5 in osteoblasts. We identified RASSF1C, a member of the RASSF1 gene products, as a IGFBP-5 binding partner and as a potential mediator of IGFBP-5 effects on ERK phosphorylation and cell proliferation.

Introduction: It has been predicted that the intrinsic growth factor action of insulin-like growth factor binding protein (IGFBP)-5 involves either the binding of IGFBP-5 to a putative receptor to induce downstream signaling pathways and/or intracellular translocation of IGFBP-5 to bind to potential signaling molecules involved in osteoblast cell regulation. This study reports the characterization of isoform C of the Ras association family 1 (RASSF1C) gene as an interacting partner of IGFBP-5.

Materials and Methods: IGFBP-5 was used as bait in a yeast two-hybrid screen of a human osteosarcoma cDNA library. Expression levels of RASSF1C were measured by RT-PCR and/or Northern blot. IGFBP-5 effects on ERK phosphorylation were evaluated by immunoblot analysis. The effect of RASSF1C siRNA on cell proliferation was measured by the AlamarBlue assay.

Results: One of the clones that interacted strongly with the bait under high stringency conditions corresponded to RASSF1C. The interaction between RASSF1C and IGFBP-5 was confirmed by in vitro co-immunoprecipitation studies. Northern blot and RT-PCR analysis showed that RASSF1C was expressed in a variety of osteoblast cell types that produce IGFBP-5. Addition of synthetic RASSF1C-specific small interfering (si) RNA duplex or use of a RASSF1C-specific si-hairpin plasmid caused a decrease in cell number and abolished IGFBP-5-induced extracellular signal-regulated kinase (ERK)-1/2 phosphorylation but had no effect on IGFBP-5-induced increases in alkaline phosphatase (ALP) activity.

Conclusions: We have shown a novel interaction between IGFBP-5 and RASSF1C. Our findings that silencing of RASSF1C results in the reduction of osteoblast cell proliferation and that IGFBP-5 treatment increases phosphorylation of ERK-1/2 raise the possibility that RASSF1C, a Ras effector, could, in part, contribute to mediating the effects of IGFBP-5 on ERK phosphorylation and, consequently, cell proliferation.
Intravenous Bisphosphonate Therapy Increases Radial Width in Adults With Osteogenesis Imperfecta
Authors: Gatti Davide , Viapiana Ombretta , Lippolis Irma , Braga Vania , Prizzi Rosangela , Rossini Maurizio , Adami Silvano
Published: April 2006

Neridronate therapy in adult patients with OI significantly increases the cross-sectional area of the proximal radius. This observation may provide an additional explanation for the antifracture efficacy of bisphosphonates.

Introduction: Bisphosphonate therapy decreases by 70-90% the fracture risk in patients with osteogenesis imperfecta (OI). This decrease is somewhat greater than that expected from the BMD changes, supporting the hypothesis that bisphosphonate therapy is associated with structural changes, not detectable by BMD measurements.

Materials and Methods: To explore this hypothesis, pQCT measurements at the nondominant radius were obtained in a group of adult OI patients participating in a randomized clinical trial with neridronate.

Results: The total volumetric BMD of the ultradistal radius rose significantly in patients treated with neridronate and calcium + vitamin D (neridronate group) compared with patients treated with calcium + vitamin D alone (control group). No significant differences were observed in trabecular BMD and in volumetric cortical density in either group. In the neridronate group, the cross-sectional area rose significantly versus both baseline values and the control group. These latter changes were associated with ∼20% increases in bending breaking resistance index (BBRI).

Conclusion: Our observation, if extended to postmenopausal osteoporosis, may provide a new explanation for the fracture risk reduction observed in osteoporotic patients treated with bisphosphonates.
An In Vivo Model to Study Osteogenic Gene Regulation: Targeting an Avian Retroviral Receptor (TVA) to Bone With the Bone Sialoprotein (BSP) Promoter
Authors: Li Ling , Zhu JI , Tu Qisheng , Yamauchi Masato , Sodek Jaro , Karsenty Gerard , Tang Jean , Chen Jake
Published: April 2006

To study bone development in vivo, a transgenic mouse model was established in which an avian retroviral receptor (TVA) gene driven by the BSP promoter was selectively expressed in skeletal tissues. The model was validated by showing suppressed BSP expression and delayed bone and tooth formation after infection with a virus expressing a mutated Cbfa1/Runx2 gene.

Introduction: Tissue-specific expression of the avian retroviral (TVA) receptor can be used to efficiently target ectopic expression of genes in vivo. To determine the use of this approach for studies of osteogenic differentiation and bone formation at specific developmental stages, transgenic mice expressing the TVA receptor under the control of a 5-kb bone sialoprotein (BSP) promoter were generated. The mice were first analyzed for tissue-specific expression of the TVA gene and then, after infection with a viral construct, for the effects of a dominant-negative form of the Cbfa1/Runx2 transcription factor on bone formation.

Materials and Methods: We first generated transgenic mice (BSP/TVA) in which the TVA gene was expressed under the control of a 4.9-kb mouse BSP promoter. The tissue-specific expression of the TVA gene was analyzed by RT-PCR, in situ hybridization, and immunohistochemistry and compared with the expression of the endogenous BSP gene. A 396-bp fragment of mutated Cbfa1/Runx2 (Cbfa1mu) encoding the DNA-binding domain was cloned into a RCASBP (A) viral vector, which was used to infect neonatal BSP/TVA mice.

Results and Conclusion: Expression of the TVA receptor mRNA and protein in the transgenic mice was consistent with the expression of endogenous BSP. Four days after systemic infection with the Cbfa1mu-RCASBP (A) vector, RT-PCR analyses revealed that the expression of BSP mRNA in tibia and mandibles was virtually abolished, whereas a 30% reduction was seen in calvarial bone. After 9 days, BSP expression in the tibia and mandible was reduced by 45% in comparison with control animals infected with an empty RCASBP vector, whereas BSP expression in the membranous bone of calvariae was decreased ∼15%. However, after 4 and 8 weeks, there was almost no change in BSP expression in any of the bone tissues. In comparison, a reduction in osteopontin expression was only observed 9 days after viral transfection in the three bones. Histomorphological examination revealed that bone formation and tooth development were delayed in some of the mice infected with mutated Cbfa1. These studies show that BSP/TVA transgenic mice can be used to target genes to sites of osteogenesis, providing a unique system for studying molecular events associated with bone formation in vivo.
Association of the OSCAR Promoter Polymorphism With BMD in Postmenopausal Women
Authors: Kim Ghi Su , Koh Jung-Min , Chang Jae Suk , Park Byung Lae , Kim Lyoung Hyo , Park Eui Kyun , Kim Shin-Yoon , Shin Hyoung Doo
Published: April 2006

In an effort to identify genetic polymorphisms in potential candidate genes for osteoporosis, 10 variants were identified in the OSCAR gene using direct DNA sequencing, and 560 postmenopausal women were genotyped at five SNP loci, using the TaqMan method. The rare allele (G allele) of OSCAR-2322A>G (SNP in the 5′ flanking region) showed significant association with lower BMD at various bone sites in postmenopausal women (n = 560).

Introduction: BMD is the major factor for determining bone strength and osteoporotic fracture risk and is determined by both environmental and multiple genetic factors. The osteoclast-associated receptor (OSCAR) plays a critical role in osteoclast differentiation and thus is an important candidate gene for the modulation of BMD.

Materials and Methods: Through direct sequencing in 24 Korean individuals, 10 sequence variants were identified: 2 in the 5′ flanking region, 7 in the exons (including 6 nonsynonymous single-nucleotide polymorphisms [SNPs]), and 1 in an intron. Five of these polymorphisms were selected for larger-scale genotyping in postmenopausal women (n = 560). Areal BMD (g/cm2) of the anterior-posterior lumbar spine and the nondominant proximal femur was measured using DXA (Lunar Expert XL and Hologic QDR 4500-A). Lateral thoracolumbar radiographs were obtained in all subjects.

Results: Using multiple regression analysis and controlling for age, years since menopause, height, weight, and evaluation machine as covariates, the rare allele (G allele) of OSCAR-2322A>G showed significant association with lower BMD at various bone sites in postmenopausal women.

Conclusion: These findings suggest that the promoter variant in OSCAR gene (OSCAR-2322A>G) might be one of genetic determinants of BMD in postmenopausal women.
Characteristics and Familial Aggregation of Paget's Disease of Bone in Italy
Authors: Merlotti Daniela , Gennari Luigi , Galli Beatrice , Martini Giuseppe , Calabrò Anna , De Paola Vincenzo , Ceccarelli Elena , Nardi Paolo , Avanzati Annalisa , Nuti Ranuccio
Published: April 2006

This study examined the characteristics of 147 PDB cases from Italy. Our data showed a reduced clinical severity of PDB with respect to other populations and provided further support of the importance of environmental factors (rural area of residence and animal contact) in the pathogenesis of PDB. Familial aggregation was observed in 15% of cases.

Introduction: The etiology of Paget's disease of bone (PDB) remains unknown. Current evidence suggests that interactions among genetic or exogenous factors seem to be necessary for disease expression. Major epidemiological studies were performed in the United Kingdom and in other populations of British descent. To date, there are no reliable data on PDB characteristics among the Italian population, and its frequency in different areas of the country remains unknown.

Materials and Methods: In an attempt to evaluate clinical characteristics, the proportion of familial cases and the influence of environmental features on the occurrence of the disease, we studied 147 consecutive PDB patients. For all subjects, a detailed medical history was obtained, and constitutional features were recorded. Characteristics of PDB patients were compared with those obtained from 323 consecutive non-Pagetic outpatient control subjects.

Results and Conclusions: Of the 147 PDB patients, 22 (15%) had at least one other family member affected, 19 (13%) reported one family member with suspected features of PDB, and 106 (72%) were classified as sporadic PDB. Even though we observed a reduced clinical severity of PDB with respect to other populations (mean number of affected sites, 2.2 ± 1.6), we did not find any evidence of a decreased severity of the disease over time. We also found an association of PDB with animal contact (odds ratio [OR], 2.22; p < 0.0005) and a significant prevalence of PDB in rural versus urban districts (OR, 2.42; p < 0.0005). Osteoarthritis (45%), fractures (14%), hearing loss (14%), and valvular calcifications (15%) were the most observed complications. Interestingly, the geographical distribution of PDB showed a concentration of cases in rural areas of Campania and Tuscany. These areas may indicate local clustering of PDB cases in Italy, similar to that observed in other countries.
In Silico Modeling and Simulation of Bone Biology: A Proposal
Authors: Defranoux Nadine A , Stokes Cynthia L , Young Daniel L , Kahn Arnold J
Published: April 2006

Contemporary, computer-based mathematical modeling techniques make it possible to represent complex biological mechanisms in a manner that permits hypothesis testing in silico. This perspective shows how such approaches might be applied to bone remodeling and therapeutic research.

Currently, the dominant conceptual model applied in bone research involves the dynamic balance between the continual build-up and breakdown of bone matrix by two cell types, the osteoblasts and osteoclasts, acting together as a coordinated, remodeling unit. This conceptualization has served extraordinarily well as a focal point for understanding how mutations, chemical mediators, and mechanical force, as well as external influences (e.g., drugs, diet) affect bone structure and function. However, the need remains to better understand and predict the consequences of manipulating any single factor, or combination of factors, within the context of this complex system's multiple interacting pathways. Mathematical models are a natural extension of conceptual models, providing dynamic, quantitative descriptions of the relationships among interacting components. This formalization creates the ability to simulate the natural behavior of a system, as well as its modulation by therapeutic or dietetic interventions. A number of mathematical models have been developed to study complex bone functions, but most include only a limited set of biological components needed to address a few specific questions. However, it is possible to develop larger, multiscale models that capture the dynamic interactions of many biological components and relate them to important physiological or pathological outcomes that allow broader study. Examples of such models include Entelos' PhysioLab platforms. These models simulate the dynamic, quantitative interactions among a biological system's biochemicals, cells, tissues, and organs and how they give rise to key physiologic and pathophysiologic outcomes. We propose that a similar predictive, dynamical, multiscale mathematical model of bone remodeling and metabolism would provide a better understanding of the mechanisms governing these phenomena as well as serve as an in silico platform for testing pharmaceutical and clinical interventions on metabolic bone disease.
Amelioration of Osteoporosis and Hypovitaminosis D by Sunlight Exposure in Hospitalized, Elderly Women With Alzheimer's Disease: A Randomized Controlled Trial
Authors: Sato Yoshihiro , Iwamoto Jun , Kanoko Tomohiro , Satoh Kei
Published: April 2006

In a random and prospective study, Alzheimer's disease (AD) patients were assigned to regular sunlight exposure (n = 132) or sunlight deprivation (n = 132) and followed for 1 year. Serum 25-OHD level increased by 2.2-fold in the sunlight-exposed group. Eleven patients sustained fractures in the sunlight-deprived group, and three fractures occurred among the sunlight-exposed group (p = 0.0362; odds ratio = 3.7).

Introduction: A high incidence of fractures, particularly of the hip, represents an important problem in patients with Alzheimer's disease (AD), who are prone to falls and have osteoporosis. We previously showed that 25-hydroxyvitamin D (25-OHD) deficiency caused by sunlight deprivation with compensatory hyperparathyroidism causes reduced BMD in elderly women with AD. This study was undertaken to address the possibility that sunlight exposure with calcium supplementation may maintain BMD and reduce the incidence of nonvertebral fractures in elderly women with AD.

Materials and Methods: In a random and prospective study, AD patients were assigned to regular sunlight exposure (n = 132) or sunlight deprivation (n = 132) and followed for 1 year. BMD of the second metacarpal bone was measured using a computed X-ray densitometer (CXD). The CXD method measures BMD and cortical thickness at the middle of the second metacarpal bone on a radiogram of the hand and an aluminum step wedge as a standard (20 steps; 1 mm/step). Incidence of nonvertebral fractures in the two patient groups during the 1-year follow-up period was assessed.

Results and Conclusion: At baseline, average hospitalization period was 1.7 years in both groups, and activity of daily living (ADL) was decreased. Patients of both groups showed vitamin D deficiency caused by sunlight deprivation and decreased dietary intake of vitamin D with compensatory hyperparathyroidism. The exposed group patients were exposed to sunlight (3615 minutes/year). BMD increased by 2.7% in the sunlight-exposed group and decreased by 5.6% in the sunlight-deprived group (p < 0.0001). Serum 25-OHD level increased from 24.0 to 52.2 nM in the sunlight-exposed group. Eleven patients sustained fractures in the sunlight-deprived group, and three fractures occurred among the sunlight-exposed group (p = 0.0362; odds ratio = 3.7). Sunlight exposure can increase the BMD of vitamin D-deficient bone by increasing 25-OHD concentration and lead to the prevention of nonvertebral fractures.
Serum TRACP 5b Is a Useful Marker for Monitoring Alendronate Treatment: Comparison With Other Markers of Bone Turnover
Authors: Nenonen Arja , Cheng Sulin , Ivaska Kaisa K , Alatalo Sari L , Lehtimäki Terho , Schmidt-Gayk Heinrich , Uusi-Rasi Kirsti , Heinonen Ari , Kannus Pekka , Sievänen Harri , Vuori Ilkka , Väänänen H Kalervo , Halleen Jussi M
Published: April 2006

We studied clinical performance of serum TRACP 5b and other bone turnover markers, including S-CTX, U-DPD, S-PINP, S-BALP, and S-OC, for monitoring alendronate treatment. TRACP 5b had higher clinical sensitivity, area under the ROC curve, and signal-to-noise ratio than the other markers.

Introduction: The purpose of this study was to compare the clinical performance of serum TRACP 5b (S-TRACP5b) with that of other markers of bone turnover in the monitoring of alendronate treatment.

Materials and Methods: This double-blinded study included 148 healthy postmenopausal women that were randomly assigned into two groups: one receiving 5 mg alendronate daily (n = 75) and the other receiving placebo (n = 73) for 12 months. All individuals in both groups received calcium and vitamin D daily. The bone resorption markers S-TRACP5b, serum C-terminal cross-linked telopeptides of type I collagen (S-CTX), and total urinary deoxypyridinoline (U-DPD), and the serum markers of bone formation procollagen I N-terminal propeptide (S-PINP), bone-specific alkaline phosphatase (S-BALP), and total osteocalcin (S-OC) were assessed at baseline and at 3, 6, and 12 months after initiation of treatment. Lumbar spine BMD (LBMD) was measured at baseline and 12 months.

Results: Compared with the placebo group, LBMD increased, and all bone markers decreased significantly more in the alendronate group (p < 0.001 for each parameter). The decrease of S-TRACP5b after first 3 months of alendronate treatment correlated significantly with the changes of all other markers except S-OC, the best correlation being with S-CTX (r = 0.60, p < 0.0001). The changes of LBMD at 12 months only correlated significantly with the changes of S-TRACP5b (r = −0.32, p = 0.005) and S-CTX (r = −0.24, p = 0.037) at 3 months. Based on clinical sensitivity, receiver operating characteristic (ROC) curves, and signal-to-noise ratio, S-TRACP5b, S-CTX, and S-PINP were the best markers for monitoring alendronate treatment. Clinical sensitivity, area under the ROC curve, and signal-to-noise ratio were higher for S-TRACP5b than for the other markers.

Conclusion: These results show that S-TRACP5b, S-CTX, and S-PINP are useful markers for monitoring alendronate treatment.
Free Testosterone Is a Positive, Whereas Free Estradiol Is a Negative, Predictor of Cortical Bone Size in Young Swedish Men: The GOOD Study
Authors: Lorentzon Mattias , Swanson Charlotte , Andersson Niklas , Mellström Dan , Ohlsson Claes
Published: April 2006

In this study, we evaluated the predictive roles of sex steroids for skeletal parameters in young men (n = 1068) at the age of peak bone mass. Serum free estradiol was a negative predictor, whereas free testosterone and SHBG were positive predictors of cortical bone size.

Introduction: Previous studies have shown that free estradiol in serum is an independent predictor of areal BMD (aBMD) in elderly men. The aim of this study was to determine whether sex steroids are predictors of volumetric BMD (vBMD) and/or size of the trabecular and cortical bone compartments in young men at the age of peak bone mass.

Materials and Methods: The Gothenburg Osteoporosis and Obesity Determinants (GOOD) study consists of 1068 men, 18.9 ± 0.6 years of age. Serum levels of testosterone, estradiol, and sex hormone binding globulin (SHBG) were measured, and free levels of testosterone and estradiol were calculated. The size of the cortical bone and the cortical and trabecular vBMDs were measured by pQCT.

Results: Regression models including age, height, weight, free estradiol, and free testosterone showed that free estradiol was an independent negative predictor of cortical cross-sectional area (tibia β = −0.111, p < 0.001; radius β = −0.125, p < 0.001), periosteal circumference, and endosteal circumference, whereas it was a positive independent predictor of cortical vBMD (tibia β = 0.100, p < 0.003; radius β = 0.115, p = 0.001) in both the tibia and radius. Free testosterone was an independent positive predictor of cortical cross-sectional area (tibia β = 0.071, p = 0.013; radius β = 0.064, p = 0.039), periosteal circumference, and endosteal circumference in both the tibia and radius. Neither cortical nor trabecular vBMD was associated with free testosterone. SHBG was an independent positive predictor of parameters reflecting the size of the cortical bone, including cross-sectional area (β = 0.078, p = 0.009), periosteal circumference, and endosteal circumference.

Conclusions: Free estradiol is a negative, whereas free testosterone is a positive, predictor of cortical bone size in young men at the age of peak bone mass. These findings support the notion that estrogens reduce, whereas androgens increase, cortical bone size, resulting in the well-known sexual dimorphism of cortical bone geometry.
Enhanced Coactivator Binding and Transcriptional Activation of Mutant Vitamin D Receptors From Patients With Hereditary 1,25-Dihydroxyvitamin D-Resistant Rickets by Phosphorylation and Vitamin D Analogs
Authors: Liu Yan , Shen Qi , Malloy Peter J , Soliman Emad , Peng Xiaorong , Kim Sungtae , Pike J Wesley , Feldman David , Christakos Sylvia
Published: April 2006

In this study, we report that the function of certain mutant VDRs from patients with hereditary HVDRR can at least be partially restored by phosphorylation and hexafluoro 1,25(OH)2D3 analogs. Our study provides new insights into mechanisms involved in enhancement of mutant VDR function.

Introduction: 1,25-Dihydroxyvitamin D-resistant rickets (HVDRR) is a rare genetic disorder caused by inactivating mutations in the vitamin D receptor (VDR). In this study, we examined VDR from patients with HVDRR having mutations in the ligand-binding domain (F251C, I268T, H305Q, E420K). We examined methods of restoring transcriptional activity of these mutants and the mechanisms involved.

Materials and Methods: Reporter gene transcriptional assays were used to examine the activation of mutant VDRs. Western-blot analysis, glutathione S-transferase (GST) pull-down assays, and chromatin immunoprecipitation (ChIP) assays were also used in this study.

Results: Using mutant VDRs, H305Q, F251C, I268T, and 10−8 M 1,25(OH)2D3, only 10–30% of the activity of wildtype (WT) VDR in activating 24(OH)ase transcription was observed. The transcriptional response of mutant VDR mutants was significantly enhanced 2- to 3-fold by co-treatment of VDR mutant transfected COS-7 cells with 1,25(OH)2D3 and okadaic acid (OA; inhibitor of phosphatase; 50 nM). The H305Q mutant was the most responsive (90% of the response exhibited by WT VDR was restored). The E420K mutant was unresponsive to 1,25(OH)2D3 in the presence or absence of OA. The increased transcriptional response correlated with an increase in the interaction between DRIP205 and the mutant VDR. We further provide evidence that OA induces the phosphorylation of CREB-binding protein (CBP), indicating for the first time a correlation between phosphorylation of CBP and enhanced VDR function. Hexafluoro 1,25(OH)2D3 analogs (RO-26-2198 and RO-4383561) also resulted in at least a partial restoration of the transcriptional responsiveness of mutant VDRs I268T, F251C, and H305Q. Our data indicate that the enhanced potency of the hexafluoro analogs may be caused by increased DRIP205 and glucocorticoid receptor interacting protein 1 (GRIP-1) binding to VDRs and enhanced association of VDRs with DNA, as suggested by results of ChIP assays.

Conclusion: Our study provides new insights into the mechanisms involved in the enhancement of VDR function by both phosphorylation and hexafluoro analogs and forms a basis for future study of vitamin D analogs or specifically designed kinase activity mediators as potential therapy for the treatment of selected patients with HVDRR.
Sustained Nonvertebral Fragility Fracture Risk Reduction After Discontinuation of Teriparatide Treatment
Authors: Prince Richard , Sipos Adrien , Hossain Anwar , Syversen Unni , Ish-Shalom Sophia , Marcinowska Ewa , Halse Johan , Lindsay Robert , Dalsky Gail P , Mitlak Bruce H
Published: April 2006

A follow-up in 1262 women was conducted after the discontinuation of teriparatide. The hazard ratio for combined teriparatide group (20 and 40 μg) for the 50-month period after baseline was 0.57 (p = 0.002), suggesting a sustained effect in reducing the risk of nonvertebral fragility fracture.

Introduction: Treatment with teriparatide {rhPTH(1-34)} 20 and 40 μg once-daily subcutaneous dosing significantly reduced the risk of nonvertebral fragility fractures over a median exposure of 19 months.

Materials and Methods: All participants in the Fracture Prevention Trial were invited to participate in a follow-up study. Prior treatment assignments were revealed, and patients were able to receive osteoporosis treatments without restriction.

Results: Approximately 60% of the 1262 patients received an osteoporosis treatment at some time during follow-up, with greater use in the former placebo group than in the combined former teriparatide group (p < 0.05). The hazard ratios for nonvertebral fragility fractures in each teriparatide group relative to placebo were statistically significant for the 50-month period including treatment and follow-up (p < 0.03). In the follow-up period, the hazard ratio was significantly different between the 40 μg and combined groups versus placebo but not for the 20 μg group versus placebo. However, the 20 and 40 μg groups were not different from each other. Kaplan-Meier analysis of time to fracture showed that the fracture incidence in the former placebo and teriparatide groups diverged during the 50-month period including teriparatide treatment and follow-up (p = 0.009). Total hip and femoral neck BMD decreased in teriparatide-treated patients who had no follow-up treatment; BMD remained stable or further increased in patients who received a bisphosphonate after teriparatide treatment.

Conclusions: While the study design is observational, the results support a sustained effect of teriparatide in reducing the risk of nonvertebral fragility fractures up to 30 months after discontinuation of treatment.
Are We Treating Women With Postmenopausal Osteoporosis for Their Low BMD or High Fracture Risk?
Authors: Api Murat
Published: April 2006

In the field of postmenopausal osteoporosis, the quality of bone has gained more attention than the quantity, so the most important part of anti-osteoporotic efficacy of an agent translates its capacity to reduce osteoporotic fractures. Ten years' experience with alendronate has a lot of conflicting data that have to be discussed in detail. Health care professionals in the field of postmenopausal osteoporosis question the antifracture efficacy of a drug more quickly than its favorable effects on BMD. The aim of this paper is to present the complexity of the results in this 10-year trial that has caused difficulty in its interpretation. Ten-year data of alendronate resulted in inconclusive evidence because of the small sample size, high drop-out rate, heterogeneous distribution of subjects in each arm of the trial, and biologically unexplainable results of the fracture rates. The need for further well-designed trials on long-term antifracture efficacy of antiosteoporotic drugs still remains.
Primary Hyperparathyroidism and Osteosarcoma: Examination of a Large Cohort Identifies Three Cases of Fibroblastic Osteosarcoma
Authors: Jimenez Camilo , Yang Ying , Kim Hyung-Woo , Al-Sagier Fozia , Berry Donald A , El-Naggar Adel K. , Patel Shreyaskumar , Vassilopoulou-Sellin Rena , Gagel Robert F
Published: April 2006

To study a possible relationship between hyperparathyroidism and osteosarcoma, we reviewed 1234 osteosarcoma patients. In this cohort, only three patients had a diagnosis of both hyperparathyroidism and fibroblastic osteosarcoma. These results indicate that hyperparathyroidism is not more prevalent in patients with osteosarcoma than in the general population. However, the presence of hyperparathyroidism may modify the histologic and cytologic features of osteosarcoma.

Introduction: The finding of osteosarcoma in rats receiving human PTH(1-34) raised the question of whether hyperparathyroidism might be a risk factor for development of osteosarcoma in humans.

Materials and Methods: To study a possible relationship between hyperparathyroidism and osteosarcoma, we reviewed the medical records of 1234 osteosarcoma patients seen at The M.D. Anderson Cancer Center since 1948. Our study focused on clinical, biochemical, radiologic, and histopathologic findings indicative of primary hyperparathyroidism and the features of osteosarcoma.

Results: Of the 1234 cases reviewed, 3 patients had a diagnosis of both primary hyperparathyroidism and osteosarcoma. In two cases, hyperparathyroidism preceded the osteosarcoma, and in one case, both conditions were diagnosed at the same time. In two cases with concomitant hyperparathyroidism and osteosarcoma, features of osteitis fibrocystica were identified. The third patient was treated for hyperparathyroidism 3 years before osteosarcoma was diagnosed. All three patients had histologic features of fibroblastic osteosarcoma, a type that accounts for no more than 20% of osteosarcomas. To assess whether the prevalence of hyperparathyroidism was greater than expected in the normal population, we compared the age- and sex-specific prevalence in our cohort to a population of healthy individuals in Tromso, Norway. This analysis showed no significant differences between the two populations, despite the fact that a higher prevalence of hyperparathyroidism (6.9% versus 1.6%) was noted in the 60- to 69-year-old female osteosarcoma age group.

Conclusions: Our results indicate that hyperparathyroidism is not more prevalent in affected individuals with osteosarcoma than in the general population. The finding of fibroblastic osteosarcoma in all three patients raises the question of whether coexistent hyperparathyroidism may modify the cytologic and histologic features of the malignancy.
BSP and RANKL Induce Osteoclastogenesis and Bone Resorption Synergistically
Authors: Valverde Paloma , Tu Qisheng , Chen Jake
Published: April 2006

RANKL and BSP are upregulated in several bone resorptive disorders. However, the mechanisms by which these two factors might induce osteoclastogenesis and bone resorption synergistically under pathological conditions remain largely unknown.

Introduction: RANKL and bone sialoprotein II (BSP) have been shown to be upregulated in the serum of individuals with abnormally high osteoclastogenic and bone resorptive activities. Here we provide experimental evidence that RANKL and BSP induce osteoclastogenesis and bone resorption synergistically but mediate opposite effects in osteoclast survival and apoptosis.

Materials and Methods: RAW264.7 cells and mouse bone marrow-derived monocytes/macrophages were treated with human recombinant BSP in the presence and absence of RANKL. TRACP stainings, bone resorption assays, Western blotting, immunoprecipitation analyses, and semiquantitative RT-PCR were used to evaluate the effects of BSP in osteoclast differentiation and bone resorption. Survival, DNA condensation, and caspase activity assays were used to determine the putative effects of BSP in osteoclast survival and apoptosis.

Results and Conclusions: RANKL induced osteoclast differentiation and bone resorption at a higher extent in the presence than in the absence of BSP in RAW264.7 cells and bone marrow-derived monocytes/macrophages. c-Src-dependent c-Cbl phosphorylation was 8-fold higher in RAW264.7 cells treated with BSP and RANKL than in those treated with RANKL alone. Furthermore, BSP and RANKL activated the master regulator of osteoclastogenesis nuclear factor of activated T cells (NFAT)-2 and increased the mRNA expression of other differentiation markers such as cathepsin K or TRACP. Inhibition of c-Src activity or chelating intracellular calcium inhibited the synergistic effects in bone resorption and the phosphorylation of the c-Src substrate c-Cbl. Inhibition of calcineurin or intracellular calcium elevation inhibited the synergistic effects in osteoclastogenesis and decreased NFAT-2 nuclear levels. On the other hand, BSP and RANKL mediated opposite effects in osteoclast survival and apoptosis. Thus, BSP increased survival and decreased apoptosis markers in differentiated RANKL-treated RAW267.5 cells and RANKL/macrophage-colony stimulating factor (M-CSF)-treated bone marrow-derived monocytes/macrophages. In addition, RAW267.5 cells treated with BSP and RANKL exhibited decreased activation of the proapoptotic Jun N-terminal kinase pathway and increased activation of anti-apoptotic AKT pathway than cells treated with RANKL or BSP alone. Taken together, our findings suggest that BSP contributes to RANKL-mediated bone resorption by inducing osteoclastogenesis and osteoclast survival and decreasing osteoclast apoptosis.
Whole-Genome Scan for Linkage to Bone Strength and Structure in Inbred Fischer 344 and Lewis Rats
Authors: Alam Imranul , Sun Qiwei , Liu Lixiang , Koller Daniel L , Fishburn Tonya , Carr Lucinda G , Econs Michael J , Foroud Tatiana , Turner Charles H
Published: April 2006

A genome-wide genetic linkage analysis identified several chromosomal regions influencing bone strength and structure in F2 progeny of Fischer 344 x Lewis inbred rats.

Introduction: Inbred Fischer 344 (F344) and Lewis (LEW) rats are similar in body size, but the F344 rats have significantly lower BMD and biomechanical strength of the femur and spine compared with LEW rats. The goal of this study was to identify quantitative trait loci (QTL) linked to bone strength and structure in adult female F2 rats from F344 and LEW progenitors.

Materials and Methods: The 595 F2 progeny from F344 x LEW rats were phenotyped for measures of bone strength (ultimate force {Fu}; energy to break {U}; stiffness {S}) of the femur and lumbar vertebra and structure (femur midshaft polar moment of inertia {Ip}; femur midshaft cortical area; vertebral area). A genome-wide scan was completed in the F2 rats using 118 microsatellite markers at an average interval of 20 cM. Multipoint quantitative linkage analysis was performed to identify chromosomal regions that harbor QTL for bone strength and structure phenotypes.

Results: Evidence of linkage for femur and lumbar strength was observed on chromosomes (Chrs) 1, 2, 5, 10, and 19. Significant linkage for femoral structure was detected on Chrs 2, 4, 5, 7, and 15. QTLs affecting femoral strength on Chrs 2 and 5 were also found to influence femur structure. Unique QTLs on Chrs 1, 10, and 19 were found that contributed to variability in bone strength but had no significant effect on structure. Also, unique QTLs were observed on Chrs 4, 7, and 15 that affected only bone structure without any effect on biomechanics.

Conclusion: We showed multiple genetic loci influencing bone strength and structure in F344 x LEW F2 rats. Some of these loci are homologous to mouse and human chromosomes previously linked to related bone phenotypes.
Advanced Glycation End-Products Attenuate Human Mesenchymal Stem Cells and Prevent Cognate Differentiation Into Adipose Tissue, Cartilage, and Bone
Authors: Kume Shinichiro , Kato Seiya , Yamagishi Sho-ichi , Inagaki Yosuke , Ueda Seiji , Arima Nobuyuki , Okawa Takahiro , Kojiro Masamichi , Nagata Kensei
Published: April 2006

The impact of AGEs on human MSCs was studied. AGEs inhibited the proliferation of MSCs, induced apoptosis, and prevented cognate differentiation into adipose tissue, cartilage, and bone, suggesting a deleterious effect of AGEs in the pathogenesis of musculoskeletal disorders in aged and diabetic patients.

Introduction: Advanced glycation end-products (AGEs) are accumulated on long-lived proteins of various tissues in advanced age and diabetes mellitus and have been implicated in chronic complication, including musculoskeletal disorders. Human mesenchymal stem cells (MSCs) potentially differentiate into mature musculoskeletal tissues during tissue repair, but the pathogenetic role of AGEs on MSCs is unclear.

Materials and Methods: AGEs were prepared by incubating BSA with glucose, glyceraldehydes, or glycolaldehyde (designated as AGE-1, AGE-2, or AGE-3, respectively). Proliferation, apoptosis, and reactive oxygen species (ROS) generation were assayed in AGE-treated cells. The expression of the receptor for AGE (RAGE) was examined by immunohistochemistry and Western blotting. Involvement of RAGE-mediated signaling was examined using a neutralizing antiserum against RAGE. Differentiation into adipose tissue, cartilage, and bone were morphologically and biochemically monitored with specific markers for each.

Results: AGE-2 and AGE-3, but not control nonglycated BSA and AGE-1, reduced the viable cell number and 5-bromo-2'deoxyuridine (BrdU) incorporation with increased intracellular ROS generation and the percentage of apoptotic cells. MSCs expressed RAGE and its induction was stimulated by AGE-2 and AGE-3. These AGEs inhibited adipogenic differentiation (assayed by oil red O staining, lipoprotein lipase production, and intracellular triglyceride content) and chondrogenic differentiation (assayed by safranin O staining and type II collagen production). On osteogenic differentiation, AGE-2 and AGE-3 increased alkaline phosphatase activity and intracellular calcium content; however, von Kossa staining revealed the loss of mineralization and mature bone nodule formation. The antiserum against RAGE partially prevented AGE-induced cellular events.

Conclusion: AGE-2 and AGE-3 may lead to the in vivo loss of MSC mass and the delay of tissue repair by inhibiting the maturation of MSC-derived cells. The AGE-RAGE interaction may be involved in the deleterious effect of AGEs on MSCs.
Differential Contribution of Osteoclast- and Osteoblast-Lineage Cells to CpG-Oligodeoxynucleotide (CpG-ODN) Modulation of Osteoclastogenesis
Authors: Amcheslavsky Alla , Hemmi Hiroaki , Akira Shizuo , Bar-Shavit Zvi
Published: April 2006

CpG-ODNs modulate osteoclast differentiation through Toll-like receptor 9 (TLR9). Using TLR9-deficient mice, we found that activation of TLR9 on both osteoclast precursors and osteoblasts mediate the osteoclastogenic effect of CpG-ODN. Osteoclastic TLR9 is more important for this activity.

Introduction: Bacterial infections cause pathological bone loss by accelerating differentiation and activation of the osteoclast. A variety of bacteria-derived molecules have been shown to enhance osteoclast differentiation through activation of Toll-like receptors (TLRs). We have shown that CpG-oligodeoxynucleotides (CpG-ODNs), mimicking bacterial DNA and exerting their cellular activities through TLR9, modulate osteoclast differentiation in a complex manner: the ODNs inhibit the activity of the physiological osteoclast differentiation factor RANKL in early osteoclast precursors (OCPs) but markedly stimulate osteoclastogenesis in cells primed by RANKL.

Materials and Methods: Osteoclast precursors and osteoblasts from TLR9-deficient (TLR9−/−) and wildtype (TLR9+/+) mice were used for in vitro analyses of osteoclast differentiation and modulation of signal transduction and gene expression.

Results: As expected CpG-ODN did not exert any activity in cells derived from TLR9−/−mice; these cells, however, responded in a normal manner to other stimuli. Using bone marrow/osteoblasts co-cultures from all possible combinations of TLR9−/− and TLR9+/+ mice-derived cells, we showed that TLR9 in the two lineages is required for CpG-ODN induction of osteoclastogenesis.

Conclusions: CpG-ODN modulates osteoclastogenesis in a TLR9-dependent manner. Activation of TLR9 in bone marrow-derived osteoclasts precursors is more crucial to induction of osteoclastogenesis than activation of the osteoblastic TLR9.
A Vacuolar ATPase Inhibitor, FR167356, Prevents Bone Resorption in Ovariectomized Rats With High Potency and Specificity: Potential for Clinical Application
Authors: Niikura Kazuaki , Takeshita Nobuaki , Takano Mikiko
Published: April 2006

FR167356, a novel inhibitor of vacuolar ATPase, has high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. FR167356 is the first compound of this nature to be tested. It has the potential to be useful for clinical application.

Introduction: It has been suggested that the key issue regarding the therapeutic usefulness of V-ATPase inhibitors is their selectivity.

Materials and Methods: In in vitro and in vivo studies, we compared FR167356 with other vacuolar ATPase (V-ATPase) inhibitors, bafilomycin A1 and SB242784. H+ transport by various membrane vesicles was assayed by measuring uptake of acridine orange. Inhibitory activity against in vitro bone resorption was examined by measuring the Ca2+ release from cultured calvariae. In vivo, hypercalcemia was induced by retinoic acid in thyroparathyroidectomized-ovariectomized rats, and the effect on serum Ca2+ level was assessed. Ovariectomized rats were treated with FR167356 or SB242784. One week after surgery, free deoxypyridinoline levels in 24-h urine samples, which were collected from 6 h after administration of FR167356, were measured by ELISA. After 4 weeks of treatment, plasma biochemical parameters were analyzed. BMD of the distal femur metaphysis was measured with pQCT. Histomorphometric analysis of the proximal tibias was performed. Blood gases of rats treated with FR167356 were measured with a blood gas analyzer for estimating the effect of FR167356 on in vivo function of renal V-ATPase.

Results: FR167356, which is distinctly different from other V-ATPase inhibitors, has a high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. Similarly, FR167356 inhibited bone resorption in vitro when stimulated by PTH, IL-1, and IL-6. FR167356 reduced retinoic acid-induced hypercalcemia in thyroparathyroidectomized-ovariectomized rats in a dose-dependent manner. Moreover, FR167356 was shown to restore BMD of ovariectomized rats caused by the inhibition of bone resorption. Ovariectomized rats treated with FR167356 did not show adverse symptoms, whereas SB242784 caused a decrease in body weight gain and significant changes in two plasma biochemical parameters. Interestingly, FR167356 treatment did not affect blood acid-base balance; however, FR167356 inhibited renal V-ATPase with a similar potency as for osteoclast V-ATPase inhibition.

Conclusion: Comparison of FR167356 with SB242784 implies that the characteristics of FR167356 may be more appropriate for clinical application as a V-ATPase inhibitor.
Prevalence of Paget's Disease of Bone in Italy
Authors: Gennari Luigi , Di Stefano Marco , Merlotti Daniela , Giordano Nicola , Martini Giuseppe , Tamone Cristina , Zatteri Roberto , De Lucchi Roberto , Baldi Carlo , Vattimo Angelo , Capoccia Silvia , Burroni Luca , Geraci Simone , De Paola Vincenzo , Calabrò Anna , Avanzati Annalisa , Isaia Giancarlo , Nuti Ranuccio
Published: April 2006

We examined the prevalence of PDB in Italy from radiological, scintigraphic, and biochemical surveys in two Italian towns. Prevalence rates varied from 0.7% to 2.4%, were higher in males than in females, and slightly differed between the two towns. Unlike previous studies in populations of British descent, no secular trend for a decreasing prevalence emerged.

Introduction: Clinical, radiological, and necropsy data from different countries suggested pronounced geographical variations in the prevalence of Paget's disease of bone (PDB). Despite the impact of the disease on the population, there are limited data on the prevalence of PDB in Italy.

Materials and Methods: The objective of this study was to estimate the prevalence of PDB in the district of Siena (Central Italy) and Turin (Northern Italy) from radiological, biochemical, and scintigraphic surveys. We examined a sample of 1778 consecutive pelvic radiographs performed between 1999 and 2000 at the Hospital Radiology Unit in Siena and 6609 pelvic radiographs performed in 1986–1987, 1992–1993, and 1999–2002 from the Radiology Department of Molinette Hospital in Turin. In Siena, 7906 consecutive99mTC-MDP bone scans performed over a 4-year period (January 2000 to May 2004) were also screened for the presence of PDB, and the prevalence of elevated alkaline phosphatase (ALP) levels (>300 UI/liter) was estimated from 7449 computerized medical records over a 3-year period (January 2000 to February 2003). The finding of PDB on the pelvic radiograph and bone scan was based on standardized radiological criteria.

Results: At the end of the radiological surveys, 16/1778 pelvic PDB cases (8 males and 8 females) were observed in Siena and 41/6609 (27 males and 14 females) in Turin. The crude prevalence of the disease was 0.89% in Siena and 0.62% in Turin. Given that pelvic involvement is commonly described in 60–90% of PDB patients, the estimated overall prevalence of PDB ranged from 1.0% to 1.5% in Siena and from 0.7% to 1.0% in Turin. No decrease in the prevalence of PDB was evident after comparison of prevalence rates from different periods. Biochemical analyses showed 296/7449 subjects with elevated ALP levels and normal liver enzymes, 87 of whom had confirmed diagnosis of PDB. The estimated prevalence of biochemical PDB was 1.5%. The scintigraphic survey showed a PDB prevalence of 194/7906 (2.4%), which was significantly higher than the radiological and biochemical estimates.

Conclusions: Our surveys suggest that PDB in Italy has an estimated prevalence of at least 1%, comparable with that observed in United States and other European countries, but lower than that described in Britain and New Zealand. No secular trend for a decreasing prevalence of PDB was observed.