Evaluation and measurement of bone mass

Carbamazepine regulates USP10 through miR-20a-5p to affect the deubiquitination of SKP2 and inhibit osteogenic differentiation

BACKGROUND

Antiepileptic drugs (AEDs) harm bone health and are significantly associated with osteoporosis development. In this study, we aimed to explore the mechanisms involved in carbamazepine (CBZ) and microRNA (miR)-20a-5p/ubiquitin-specific peptidase 10 (USP10)/S-phase kinase-associated protein 2 (SKP2) axis in osteoporosis.

METHODS

Human bone marrow mesenchymal stem cells (BMSCs) were treated with different concentrations of CBZ. Knocking down or overexpressing miR-20a-5p, USP10, and SKP2 cell lines were constructed. The expressions of miR-20a-5p, USP10, SKP2, runt-related transcription factor 2 (Runx2), Alkaline phosphatase (ALP), Osterix (Osx), osteocalcin (OCN) and Collagen I were detected with western blot (WB) and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). Alizarin Red S (ARS) staining was performed to measure calcium deposition. Dual-luciferase assay and RNA immunoprecipitation (RIP) were applied to verify the binding relationship between miR-20a-5p and USP10. USP10 and SKP2 combination was verified by Co-Immunopurification (Co-IP). The stability of the SKP2 protein was verified by Cycloheximide chase assay.

RESULTS

CBZ could reduce cell activity. ALP activity and ARS staining were enhanced in the osteogenic induction (OM) group. The expressions of Runx2, ALP, Osx, OCN and Collagen I were increased. CBZ reduced miR-20a-5p expressions. Verification experiments showed miR-20a-5p could target USP10. USP10 increased SKP2 stability and promoted SKP2 expression. CBZ regulated miR-20a-5p/USP10/SPK2 and inhibited BMSCs osteogenic differentiation.

CONCLUSIONS

CBZ regulated USP10 through miR-20a-5p to affect the deubiquitination of SKP2 and inhibit osteogenic differentiation, which provided a new idea for osteoporosis treatment.

Optimization of an α-aminonaphthylmethylphosphonic acid inhibitor of purple acid phosphatase using rational structure-based design approaches

Purple acid phosphatases (PAPs) are ubiquitous binuclear metallohydrolases that have been isolated from various animals, plants and some types of fungi. In humans and mice, elevated PAP activity in osteoclasts is associated with osteoporosis, making human PAP an attractive target for the development of anti-osteoporotic drugs. Based on previous studies focusing on phosphonate scaffolds, as well as a new crystal structure of a PAP in complex with a derivative of a previously synthesized α-aminonaphthylmethylphosphonic acid, phosphonates 24-40 were designed as new PAP inhibitor candidates. Subsequent docking studies predicted that all of these compounds are likely to interact strongly with the active site of human PAP and most are likely to interact strongly with the active site of pig PAP. The seventeen candidates were synthesized with good yields and nine of them (26-28, 30, 33-36 and 38) inhibit in the sub-micromolar to nanomolar range against pig PAP, with 28 and 35 being the most potent mammalian PAP inhibitors reported with Ki values of 168 nM and 186 nM, respectively. This study thus paves the way for the next stage of drug development for phosphonate inhibitors of PAPs as anti-osteoporotic agents.

Can DXA image-based deep learning model predict the anisotropic elastic behavior of trabecular bone?

3D image-based finite element (FE) and bone volume fraction (BV/TV)/fabric tensor modeling techniques are currently used to determine the apparent stiffness tensor of trabecular bone for assessing its anisotropic elastic behavior. Inspired by the recent success of deep learning (DL) techniques, we hypothesized that DL modeling techniques could be used to predict the apparent stiffness tensor of trabecular bone directly using dual-energy X-ray absorptiometry (DXA) images. To test the hypothesis, a convolutional neural network (CNN) model was trained and validated to predict the apparent stiffness tensor of trabecular bone cubes using their DXA images. Trabecular bone cubes obtained from human cadaver proximal femurs were used to obtain simulated DXA images as input, and the apparent stiffness tensor of the trabecular cubes determined by using micro-CT based FE simulations was used as output (ground truth) to train the DL model. The prediction accuracy of the DL model was evaluated by comparing it with the micro-CT based FE models, histomorphometric parameter based multiple linear regression models, and BV/TV/fabric tensor based multiple linear regression models. The results showed that DXA image-based DL model achieved high fidelity in predicting the apparent stiffness tensor of trabecular bone cubes (R² = 0.905-0.973), comparable to or better than the histomorphometric parameter based multiple linear regression and BV/TV/fabric tensor based multiple linear regression models, thus supporting the hypothesis of this study. The outcome of this study could be used to help develop DXA image-based DL techniques for clinical assessment of bone fracture risk.

Osteoporosis Associated with Epilepsy and the Use of Anti-Epileptics-a Review

The increased rate of fractures associated with epilepsy has been long recognised but remains incompletely understood. Study quality and study results have varied, with some but not all studies showing bone diseases including osteoporosis and/or osteomalacia, and a high prevalence of vitamin D insufficiency and deficiency are also noted. Falls risk can also be higher in patients with epilepsy taking anti-epileptic medications, potentially leading to fracture. Larger research collaborations are recommended to further advance understanding in this field, particularly to examine underlying genetic and pharmacogenomic associations of epilepsy and anti-epileptic medication usage and its association with bone diseases and fractures, as well as further investigation into optimal management of bone health in epilepsy.

Antiosteoporotic effect of orally administered yolk-derived peptides on bone mass in women

The main objective of this study was to verify the effect of oral intake of a yolk-derived peptide preparation (HYP) obtained by enzymatic hydrolysis of yolk water-soluble protein on bone markers and bone density in 65 perimenopausal women with an average age of 47.6 ± 5.2 years. Subjects were divided into three groups, and then enrolled in a 6-month, randomized, double-blind clinical trial. Bone formation and resorption markers were measured at 0, 3, and 6 months, while bone mineral density (BMD) in the lumbar spines was measured at 0 and 6 months. Although the bone formation marker levels showed the similarity changes among the groups, bone resorption markers in the test HYP group were significantly decreased after 3 and 6 months in comparison to other groups (P < 0.05). After 6 months, BMD in the test HYP group maintained at healthy numerical values whereas BMD values were decreased in other groups. Hence HYP would be an antiosteoporotic agent originated from natural food to maintain bone health, especially for women.

Antiepileptic drugs and bone metabolism in children: data from 128 patients

There are conflicting results concerning bone metabolism in children receiving antiepileptic medication, with data concentrating on neurologically impaired patients. We performed a multicenter cross-sectional study in otherwise healthy children who received monotherapy with valproic acid, oxcarbazepine, lamotrigine, sulthiame, levetiracetam, or topiramate for at least 6 months. Data on calcium, phosphorus, alkaline phosphatase, 25-OH vitamin D, and parathormone were collected. Among 128 patients, 24.4% had hypocalcemia, 25.4% hypophosphatemia, and 13.3% (n = 17) 25-OH vitamin D levels <10 ng/mL. All patients were clinically asymptomatic. Mean calcium concentrations were found to be significantly lower among the study population (2.41 mmol/L) compared with healthy controls (2.53 mmol/L). Lowest mean concentration was observed in patients treated with sulthiame followed by oxcarbazepine and valproic acid. No influence of calcium intake or therapy on bone metabolism was noted. Effects on bone metabolism of anticonvulsive monotherapy are not restricted to neurologically impaired children but also affect otherwise healthy children.

Bone health in children with cerebral palsy and epilepsy

Children with disabilities that limit mobility are at increased risk for osteoporosis. In the United States, 10 million people have osteoporosis and 34 million people are estimated to be at risk of acquiring this condition. Typically, bone fragility and osteoporosis have been associated with older adults; however, these problems can also affect children. The childhood and adolescent years are critically important in producing healthy bone mass. Yet cerebral palsy and epilepsy, which are both chronic disorders that frequently coexist, are predictors of muscular and skeletal compromise. Nurse practitioners should be aware of recommendations for promoting and achieving optimal bone health in children with these disabilities and screening patients who are at risk of sustaining fractures.

Bone health in adults with epilepsy

Patients with epilepsy have a 2-6 times greater risk of bone fractures compared with the general population. There are several potential explanations. Some fractures are caused by seizure-related injuries, or they may be associated with the osteopenic effect of reduced physical activity in patients with epilepsy. Antiepileptic drugs (AEDs), especially those that affect the liver enzymes, e.g., phenytoin, carbamazepine, phenobarbital, as well as valproate, are also associated with increased fracture rate and low bone mineral density. Many patients with epilepsy and general practitioners seem unaware of this problem. Measurements of bone density should be taken regularly in patients at risk of developing osteoporosis. Non-pharmaceutical initiatives, such as partaking in regular physical activity and eating a well-balanced diet, should be recommended. The risk of developing osteoporosis should be taken into consideration in the selection of an AED for treating a newly diagnosed patient with epilepsy.

Evaluation of bone turnover in epileptic children using oxcarbazepine

This study evaluated the effects of oxcarbazepine monotherapy on bone turnover in prepubertal and pubertal children. Thirty-four newly diagnosed pediatric patients with normal bone mineral density, serum biochemical markers of bone formation, and hormonal markers participated. Levels of 25-hydroxyvitamin D were significantly decreased after therapy compared with baseline values. Levels of gamma-glutamyl transferase, phosphorus, alkaline phosphatase, osteocalcin, parathyroid hormone, and calcitonin had increased. However, only changes in osteocalcin and gamma-glutamyl transferase levels were statistically significant compared with baseline values. Drug-induced osteopenia was evident in 3 patients with z scores of bone-mineral density less than -2.0, whereas these patients had z scores of less than -1.5 before treatment. Although 18 months of oxcarbazepine treatment exerted slightly adverse effects on bone metabolism, the effect seems insignificant in children with normal bone-mineral density. Although alterations in bone metabolism do not always suffice to explain the decrease in bone-mineral metabolism, we think that patients with osteopenia before the initiation of oxcarbazepine therapy should be followed carefully, especially in long-term treatment.

Bone consequences of epilepsy and antiepileptic medications

Childhood and adolescence are critical periods of skeletal mineralization. Peak bone mineral density achieved by the end of adolescence determines the risk for later pathological fractures and osteoporosis. Chronic disease and medication often adversely affect bone health. Epilepsy is one of the most common neurological conditions occurring in persons under the age of 21. Epilepsy may affect bone in a number of ways. Restrictions of physical activity imposed by seizures, cerebral palsy or other coexisting comorbidities adversely affect bone health. It has been observed that treatment with phenytoin and phenobarbital can be associated with rickets. More recently, established agents such as carbamazepine and valproate have been shown to be associated with decreased bone mineral density. The literature related to bone health in pediatric epilepsy is reviewed.

Bone mineral density with lamotrigine monotherapy for epilepsy

Bone mass, largely accumulated during childhood and adolescence, may be reduced in patients with epilepsy as a result of epilepsy or of antiepileptic medications. Enzyme-inducing medications increase bone-turnover markers, although the effects of newer medications on bone accrual are not well-defined. Total z-score bone mineral density was measured in 13 children, treated with lamotrigine monotherapy, who had never been exposed to other medications, and compared with 36 control subjects and 40 patients exposed to polytherapy. All patients were normally ambulatory and had similar physical activity and calcium intake. The z-scores of bone mineral density for lamotrigine and control subjects were similar (0.52 +/- 0.76 versus 0.49 +/- 0.7) and higher than those receiving polytherapy for 1-5 years (0.14 +/- 0.8, P = 0.12) and >or=6 years (-0.27 +/- 01.15, P < 0.003). Increasing duration of epilepsy was associated with lower bone density for 1-5 years of polytherapy (Spearman's correlation coefficient r = +0.006, P = 0.74) and >or=6 years of polytherapy (Spearman's correlation coefficient r = +0.12, P = 0.13), but not for lamotrigine. These data suggest that lamotrigine may not interfere with bone accrual.

Moderate alcohol consumption and increased bone mineral density: potential ethanol and non-ethanol mechanisms

Mounting epidemiological evidence indicates an association between the moderate ingestion of alcoholic beverages and higher bone mineral density (v. abstainers). More limited findings provide some evidence for translation of this association into reduced fracture risk, but further studies are required. Here, these data are reviewed and caveats in their assimilation, comparison and interpretation as well as in the use and application of bone health indices are discussed. Whilst it is concluded that evidence is now strong for the moderate alcohol-bone health association, at least in relation to bone mineral density, mechanisms are less clear. Both ethanol and non-ethanol components have been implicated as factors that positively affect bone health in the light of moderate consumption of alcoholic beverages, and four particular areas are discussed. First, recent findings suggest that moderate ethanol consumption acutely inhibits bone resorption, in a non-parathyroid hormone- and non-calcitonin-dependent fashion, which can only partly be attributed to an energy effect. Second, critical review of the literature does not support a role for moderate ethanol consumption affecting oestrogen status and leading to a knock-on effect on bone. Third, Si is present at high levels in certain alcoholic beverages, especially beer, and may have a measurable role in promoting bone formation. Fourth, a large body of work indicates that phytochemicals (e.g. polyphenols) from alcoholic beverages could influence bone health, but human data are lacking. With further work it is hoped to be able to model epidemiological observations and provide a clear pathway between the magnitude of association and the relative contribution of these mechanisms for the major classes of alcoholic beverage.

Femur strength index predicts hip fracture independent of bone density and hip axis length

INTRODUCTION

Proximal femoral bone strength is not only a function of femoral bone mineral density (BMD), but also a function of the spatial distribution of bone mass intrinsic in structural geometric properties such as diameter, area, length, and angle of the femoral neck. Recent advancements in bone density measurement include software that can automatically calculate a variety of femoral structural variables that may be related to hip fracture risk. The purpose of this study was to compare femoral bone density, structure, and strength assessments obtained from dual-energy X-ray absorbtiometry (DXA) measurements in a group of women with and without hip fracture.

METHODS

DXA measurements of the proximal femur were obtained from 2,506 women 50 years of age or older, 365 with prior hip fracture and 2,141 controls. In addition to the conventional densitometry measurements, structural variables were determined using the Hip Strength Analysis program, including hip axis length (HAL), cross-sectional moment of inertia (CSMI), and the femur strength index (FSI) calculated as the ratio of estimated compressive yield strength of the femoral neck to the expected compressive stress of a fall on the greater trochanter.

RESULTS

Femoral neck BMD was significantly lower and HAL significantly higher in the fracture group compared with controls. Mean CSMI was not significantly different between fracture patients and controls after adjustment for BMD and HAL. FSI, after adjustment for T score and HAL, was significantly lower in the fracture group, consistent with a reduced capacity to withstand a fall without fracturing a hip.

CONCLUSION

We conclude that BMD, HAL, and FSI are significant independent predictors of hip fracture.

A simple non invasive computerized method for the assessment of bone repair within osteoconductive porous bioceramic grafts

Single energy X-ray imaging, due to its low cost and flexibility, is one of the most used and common technique to assess bone state and bone remodeling over time. Standardized X-ray images are needed to compare sets of radiographs for semi-quantitative analyses of tissue remodeling. However, useful mathematical modeling for the analysis of high level radiographic images are not easily available. In order to propose a useful evaluation tool to a wide clinical scenario, we present an innovative calibration algorithm for a semi-quantitative analysis of non-standardized digitized X-ray images. For calibration on a unique standardization scale, three time invariant regions (ROI) of radiographs were selected and analyzed. The accuracy of the normalization method for X-ray films was successfully validated by using an aluminum step wedge for routine X-ray exposures as tool to standardize serial radiographs (Pearson correlation test: R(2) = 0.96). This method was applied to investigate the progression of the new bone deposition within ceramic scaffolds used as osteoconductive substitute in large bone defects taking advantage of a large animal model. This innovative image-processing algorithm allowed the identification and semi-quantification of the bone matrix deposited within the implant. The osteo-integration at the bone-implant interface was also investigated. A progressively increasing bone tissue deposition within the porous bioceramic implant and a progressive osteo-integration was observed during the 12 months of the trial.