Formation Dominates Resorption With Increasing Mineralized Density and Time Postfracture in Cortical but Not Trabecular Bone: A Longitudinal HRpQCT Imaging Study in the Distal Radius.

Clinical evaluation of fracture healing is often limited to an assessment of fracture bridging from radiographic images, without consideration for other aspects of bone quality. However, recent advances in HRpQCT offer methods to accurately monitor microstructural bone remodeling throughout the healing process. In this study, local bone formation and resorption were investigated during the first year post fracture in both the fractured (n = 22) and contralateral (n = 19) radii of 34 conservatively treated patients (24 female, 10 male) who presented with a unilateral radius fracture at the Innsbruck University Hospital, Austria. HRpQCT images and clinical metrics were acquired at six time points for each patient. The standard HRpQCT image acquisition was captured for all radii, with additional distal and proximal image acquisitions for the fractured radii. Measured radial bone densities were isolated with a voxel-based mask and images were rigidly registered to images from the previous imaging session using a pyramid-based approach. From the registered images, bone formation and resorption volume fractions were quantified for multiple density-based thresholds and compared between the fractured and contralateral radius and relative to demographics, bone morphometrics, and fracture metrics using regression. Compared with the contralateral radius, both bone formation and resorption were significantly increased in the fractured radius throughout the study for nearly all evaluated thresholds. Higher density cortical bone formation continually increased throughout the duration of the study and was significantly greater than resorption during late-stage healing in both the fractured and intact regions of the radius. With the small and diverse study population, only weak relationships between fracture remodeling and patient-specific parameters were unveiled. However this study provides methods for the analysis of local bone remodeling during fracture healing and highlights relevant considerations for future studies, specifically that remodeling postfracture is likely to continue beyond 12-months postfracture. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A Cross-Sectional Cohort Study of the Effects of FGF23 Deficiency and Hyperphosphatemia on Dental Structures in Hyperphosphatemic Familial Tumoral Calcinosis.

Hyperphosphatemic familial tumoral calcinosis (HFTC) is a rare autosomal recessive disorder caused by mutations in FGF23, GALNT3, KLOTHO, or FGF23 autoantibodies. Prominent features include high blood phosphate and calcific masses, usually adjacent to large joints. Dental defects have been reported, but not systematically described. Seventeen patients with HFTC followed at the National Institutes of Health underwent detailed clinical, biochemical, molecular, and dental analyses. Studies of teeth included intraoral photos and radiographs, high-resolution µCT, histology, and scanning electron microscopy (SEM). A scoring system was developed to assess the severity of tooth phenotype. Pulp calcification was found in 13 of 14 evaluable patients. Short roots and midroot bulges with apical thinning were present in 12 of 13 patients. Premolars were most severely affected. µCT analyses of five HFTC teeth revealed that pulp density increased sevenfold, whereas the pulp volume decreased sevenfold in permanent HFTC teeth compared with age- and tooth-matched control teeth. Histology revealed loss of the polarized odontoblast cell layer and an obliterated pulp cavity that was filled with calcified material. The SEM showed altered pulp and cementum structures, without differences in enamel or dentin structures, when compared with control teeth. This study defines the spectrum and confirms the high penetrance of dental features in HFTC. The phenotypes appear to be independent of genetic/molecular etiology, suggesting hyperphosphatemia or FGF23 deficiency may be the pathomechanistic driver, with prominent effects on root and pulp structures, consistent with a role of phosphate and/or FGF23 in tooth development. Given the early appearance and high penetrance, cognizance of HFTC-related features may allow for earlier diagnosis and treatment. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

The Effect of Single Versus Group µCT on the Detection of Trabecular and Cortical Disease Phenotypes in Mouse Bones.

Micro-computed tomography is a critical assessment tool for bone-related preclinical research, especially in murine models. To expedite the scanning process, researchers often image multiple bones simultaneously; however, it is unknown if this impacts scan quality and alters the ability to detect differences between experimental groups. The purpose of this study was to assess the effect of multibone scanning on detecting disease-induced changes in bone microarchitecture and mineral density by group scanning two murine models with known skeletal defects: the Col1a2 G610C/+ model of osteogenesis imperfecta and an adenine-induced model of chronic kidney disease. Adult male femurs were scanned individually and in random groups of three and eight in a Bruker Skyscan 1172 and 1176, respectively, then assessed for standard trabecular and cortical bone measures. Although scanning methodology altered raw values, with trabecular microarchitecture values more affected than cortical properties, a disease phenotype was still detectable in both group and solo scans. However, tissue mineral density in both trabecular and cortical bone was significantly impacted by group versus solo scanning. Researchers may be able to use small groupings in a single µCT scan to expedite preclinical analyses when the overall bone phenotype is large to decrease costs and increase speed of discoveries; however the details of scanning (single or group) should always be reported. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A Bisphosphonate With a Low Hydroxyapatite Binding Affinity Prevents Bone Loss in Mice After Ovariectomy and Reverses Rapidly With Treatment Cessation.

Bisphosphonates (BPs) are a mainstay of osteoporosis treatment; however, concerns about bone health based on oversuppression of remodeling remain. Long-term bone remodeling suppression adversely affects bone material properties with microdamage accumulation and reduced fracture toughness in animals and increases in matrix mineralization and atypical femur fractures in patients. Although a "drug holiday" from BPs to restore remodeling and improve bone quality seems reasonable, clinical BPs have long functional half-lives because of their high hydroxyapatite (HAP) binding affinities. This places a practical limit on the reversibility and effectiveness of a drug holiday. BPs with low HAP affinity and strong osteoclast inhibition potentially offer an alternative approach; their antiresorptive effect should reverse rapidly when dosing is discontinued. This study tested this concept using NE-58025, a BP with low HAP affinity and moderate osteoclast inhibition potential. Young adult female C57Bl/6 mice were ovariectomized (OVX) and treated with NE-58025, risedronate, or PBS vehicle for 3 months to test effectiveness in preventing long-term bone loss. Bone microarchitecture, histomorphometry, and whole-bone mechanical properties were assessed. To test reversibility, OVX mice were similarly treated for 3 months, treatment was stopped, and bone was assessed up to 3 months post-treatment. NE-58025 and RIS inhibited long-term OVX-induced bone loss, but NE-58025 antiresorptive effects were more pronounced. Withdrawing NE-58025 treatment led to the rapid onset of trabecular resorption with a 200% increase in osteoclast surface and bone loss within 1 month. Cessation of risedronate treatment did not lead to increases in resorption indices or bone loss. These results show that NE-58025 prevents OVX-induced bone loss, and its effects reverse quickly following cessation treatment in vivo. Low-HAP affinity BPs may have use as reversible, antiresorptive agents with a rapid on/off profile, which may be useful for maintaining bone health with long-term BP treatment. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Cornelian cherry extract ameliorates osteoporosis associated with hypercholesterolemia in New Zealand rabbits.

BACKGROUND: Results of animal studies show that a high-cholesterol diet increases bone resorption and decreases bone formation, thus leading to osteoporosis. Previously, we reported on the beneficial influence of Cornelian cherry (Cornus mas L.) fruit on lipid profile in an animal model of diet-induced hipercholesterolemia. OBJECTIVES: To investigate the influence of Cornus mas L. extract and loganic acid (LA) on cholesterol-induced bone changes. MATERIAL AND METHODS: The study was conducted on 50 New Zealand rabbits. The animals were given either standard chow (group P) or the same standard chow enriched with 1% cholesterol (other groups). Additionally, the group CHOL+EX received Cornus mas L. extract, group CHOL+LA - loganic acid, and group CHOL+SIM - simvastatin. Serum concentration of bone turnover markers, bone mineral density (BMD) and bone micro-computed tomography (microCT) were assessed. RESULTS: In the CHOL group, a decrease in osteocalcin (OC) and an increase in C-terminated telopeptide of type I collagen (CTX) levels were detected (CHOL vs P 0.674 ±0.159 ng/mL vs 1.003 ±0.297 ng/mL and 10.049 ±1.276 ng/mL vs 7.721 ±1.187 ng/mL, respectively). The EX and LA ameliorated cholesterol-induced changes in serum OC (0.857 ±0.160 ng/mL and 1.103 ±0.356 ng/mL, respectively) and CTX (7.735 ±1.045 ng/mL and 8.128 ±1.106 ng/mL, respectively). There was a significant decrease in femoral BMD in CHOL group (0.429 ±0.11 g/cm² vs 0.449 ±0.020 g/cm²). The EX and LA ameliorated those changes (0.458 ±0.016 g/cm² and 0.449 ±0.021 g/cm², respectively). The microCT revealed increased bone volume ratio (BV/TV) and trabecular thickness (Tb.Th.) in the CHOL+EX group. CONCLUSIONS: Cornus mas L. inhibited bone resorption and stimulated bone formation, thereby preventing the development of cholesterol-induced osteoporosis.

Assessment of cortical bone microdamage following insertion of microimplants using optical coherence tomography: a preliminary study.

OBJECTIVES: The study was done to evaluate the efficacy of optical coherence tomography (OCT), to detect and analyze the microdamage occurring around the microimplant immediately following its placement, and to compare the findings with micro-computed tomography (µCT) images of the samples to validate the result of the present study. METHODS: Microimplants were inserted into bovine bone samples. Images of the samples were obtained using OCT and µCT. Visual comparisons of the images were made to evaluate whether anatomical details and microdamage induced by microimplant insertion were accurately revealed by OCT. RESULTS: The surface of the cortical bone with its anatomical variations is visualized on the OCT images. Microdamage occurring on the surface of the cortical bone around the microimplant can be appreciated in OCT images. The resulting OCT images were compared with the µCT images. A high correlation regarding the visualization of individual microcracks was observed. The depth penetration of OCT is limited when compared to µCT. CONCLUSIONS: OCT in the present study was able to generate high-resolution images of the microdamage occurring around the microimplant. Image quality at the surface of the cortical bone is above par when compared with µCT imaging, because of the inherent high contrast and high-resolution quality of OCT systems. Improvements in the imaging depth and development of intraoral sensors are vital for developing a real-time imaging system and integrating the system into orthodontic practice.

Towards a multidimensional scientific approach to improve clinical practices for infertility treatment.

Polycystic ovary syndrome (PCOS) is the most common metabolic and endocrine disorder in women, leading to infertility. However, there is no general agreement concerning how to diagnose and treat PCOS. The Rotterdam consensus statement from the European Society of Human Reproduction and Embryology/American Society for Reproductive Medicine, the Chinese diagnostic criteria and consensus statement, and the clinical practice guideline from the Endocrine Society in the USA are widely recognized. Guidance has been provided for clinical practice based on a comparative analysis of the above three practice guidelines or consensus statements (Wang et al., 2018a). High body mass index (BMI) has no negative effect on the outcome of in vitro fertilization (IVF) in Chinese patients with PCOS; however, the conclusion may be limited by the retrospective design and potential bias (Pan et al., 2018). Neonatal birth weight is positively affected by both maternal pre-pregnancy body mass index (pre-BMI) and gestational weight gain (Du et al., 2017). Normal body weight is very important for conception. Women with PCOS are almost 3 times more likely to be obese than those without PCOS; however, no specific interventions are available to induce weight loss, and drugs are used to treat other symptoms of the syndrome or obesity in the general population. A network meta-analysis found that the amount of weight loss differed significantly according to the choice of drugs (in descending order): liraglutide, orlistat, and metformin. Liraglutide alone, liraglutide/metformin, and metformin alone significantly reduced waist circumference, but no change was found with orlistat, indicating liraglutide appears superior to the other drugs in reducing weight and waist circumference (Wang et al., 2018b). IVF, as a choice for more than 1 000 000 infertile couples each year, gives rise to the birth of over 3 000 000 babies worldwide.

Comparison of calcimimetic R568 and calcitriol in mineral homeostasis in the Hyp mouse, a murine homolog of X-linked hypophosphatemia.

X-linked hypophosphatemia (XLH) caused by mutations in the Phex gene is the most common human inherited phosphate wasting disorder characterized by enhanced synthesis of fibroblast growth factor 23 (FGF23) in bone, renal phosphate wasting, 1,25(OH)2D3 (1,25D) deficiency, rickets and osteomalacia. Here we studied the effects of calcimimetic R568 and calcitriol treatment in the Hyp mouse, a murine homolog of XLH. We hypothesized that mineral homeostasis is differentially affected by R568 and 1,25D with respect to the PTH-vitamin D-FGF23-Klotho axis and bone health. Four-week-old male Hyp mice received R568 in different doses, 1,25D or vehicle for 28days. Vehicle-treated wild-type mice served as controls. Both R568 and 1,25D reduced PTH levels, yet only 1,25D raised serum phosphate levels in Hyp mice. 1,25D increased calciuria and further enhanced FGF23 synthesis in bone and circulating FGF23 levels. By contrast, R568 reduced bone FGF23 expression and serum total but not intact FGF23 concentrations. Renal 1,25D metabolism was further impaired by 1,25D and improved although not normalized by R568. Hyp mice showed reduced renal Klotho levels, which were increased by 1,25D and high dose R568. 1,25D, but not R568, significantly improved femur growth, and weight gain, and partially restored growth plate morphology and bone mineralization. Although a significant improvement of trabecular bone was noted by µCT, compared to 1,25D the effects of R568 on bone histomophometric parameters were marginal. Our data indicate that monotherapy with R568 reduced PTH and FGF23 synthesis in bone, but failed to restore vitamin D and phosphate metabolism and skeletal abnormalities in Hyp mice. By contrast, 1,25D improved body growth, and defective mineralization despite further enhancement of skeletal FGF23 synthesis thereby highlighting the importance of vitamin D in bone mineralization in Hyp mice.