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1.
Braz Oral Res ; 34: e016, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32130363

RESUMO

Horizontal bone loss after tooth extraction is a common finding that demands bone reconstruction in various cases. The aim of this study was to assess the horizontal alveolar status in partially and completely edentulous patients using cone-beam computed tomography (CBCT). In total, 1516 CBCT scans of 1404 adult patients were analyzed. Assessment of the images was performed in accordance with the previously published horizontal alveolar change (HAC) classification, which categorizes horizontal bone defects into four classes: HAC 1, HAC 2, HAC 3 and HAC 4 (from the least severe to the most severe condition). Analysis of 1048 scans from partially edentulous patients presented a distribution of 63.55%, 22.14%, 13.36% and 0.95% in HAC 1, HAC 2, HAC 3 and HAC 4, respectively. Analysis of 468 scans from completely edentulous patient images presented a distribution of 19.87%, 28.63%, 41.67% and 9.83% in HAC 1, HAC 2, HAC 3 and HAC 4, respectively. Based on these results, as in HAC 4, no cancellous bone was found between the cortical buccal and lingual/palatal bone plates, it seems reasonable to state that the absence of cancellous bone is higher in completely edentulous patients than in partially edentulous patients. Therefore, the absence of cancellous bone seems to be higher in completely edentulous than in partially edentulous patients.


Assuntos
Perda do Osso Alveolar/epidemiologia , Perda do Osso Alveolar/patologia , Processo Alveolar/patologia , Boca Edêntula/epidemiologia , Boca Edêntula/patologia , Adolescente , Adulto , Idoso , Perda do Osso Alveolar/diagnóstico por imagem , Processo Alveolar/diagnóstico por imagem , Aumento do Rebordo Alveolar , Brasil/epidemiologia , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/patologia , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Boca Edêntula/diagnóstico por imagem , Prevalência , Estudos Retrospectivos , Adulto Jovem
2.
Comput Methods Biomech Biomed Engin ; 23(2): 54-68, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31813291

RESUMO

Osteoporosis is an osteometabolic disease, which promotes structural degradation of bone tissue and reduction of mineral density. We reported here a mechanical resistance assay from normal, osteopenic and osteoporotic trabecular vertebral bones of human cadavers. We performed a compressed test on ninety samples, evaluating Young's modulus and X-ray microtomography to measure bone volume fraction and trabecular thickness. This experimental data are employed for computing the orthotropic macroscopic behavior of vertebral trabecular bones using known analytical formulae that were obtained by Galka et al. (Arch Mech 51: 335-355, 1999) via an asymptotic homogenization model. A geometrical model with a periodic orthogonal plate-like structure is applied. The properties of the bone-trabecular mass are considered linear, homogeneous and orthotropic. Average values for all technical or engineering elastic properties are computed for three important regions of the trabecular bones corresponding to thirty individuals classified as normal, osteopenic or osteoporotic by calcaneus ultrassometry. This study could be useful for a better understanding of the elastic behavior of trabecular bones in human vertebral bodies, allowing an estimation of bone answer under stress in different directions and the risk of fracture associated with osteoporosis.HighlightsDescribing the elastic behavior of trabecular bones in human vertebral bodies at the micro and macroscopic.Allow a better estimation of the stress in different directions and risk of fracture associated with osteoporosis.Model request a very low computational cost.Offer a better understand the global effective coefficients of samples of trabecular bone, from the model of a periodic unit cell, in the format orthogonal plate-like structure with homogeneous bone mass.


Assuntos
Osso Esponjoso/fisiopatologia , Osteoporose/fisiopatologia , Coluna Vertebral/fisiopatologia , Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Módulo de Elasticidade , Elasticidade , Humanos , Masculino , Osteoporose/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Microtomografia por Raio-X
3.
J Shoulder Elbow Surg ; 29(1): 167-174, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473132

RESUMO

BACKGROUND: Little is known about the cortical-like and cancellous bone density variations in superiorly eroded glenoids due to cuff tear arthropathy. The purpose of this study was to analyze regional bone density in type E2 glenoids. METHODS: Clinical shoulder computed tomography scans were obtained from 32 patients with a type E2 superior erosion (10 men and 22 women; mean age, 73 years). Measurement regions were organized into quadrants (superior, inferior, anterior, and posterior) and depth regions. The depth regions were incremented by 2 mm from 0 to 10 mm. A repeated-measures multiple analysis of variance was performed to assess differences and interactions between mean densities (cortical-like and cancellous bone) in each depth, in each quadrant, and between sexes. RESULTS: The lowest cancellous bone density was found in the inferior glenoid quadrant compared with all other quadrants (307 ± 50 Hounsfield units [HU], P < .001). At the glenoid surface, the superior quadrant contained the highest mean density for cortical-like bone (895 ± 97 HU); this differed significantly from the posterior, anterior, and inferior quadrants (P ≤ .033). As for depth of measurement, cortical-like bone was most dense at the glenoid surface (0-2 mm, 892 ± 91 HU), and density decreased significantly at depths greater than 2 mm (P ≤ .019). CONCLUSION: In patients with type E2 glenoids due to cuff tear arthropathy, the densest bone was found in the superior quadrant in the area of erosion. The inferior quadrant, which tends to be unloaded as the humeral head migrates superiorly, had the lowest density bone. In addition, the best-quality bone was located at the glenoid surface as compared with deeper in the vault.


Assuntos
Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Cavidade Glenoide/diagnóstico por imagem , Artropatia de Ruptura do Manguito Rotador/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Cavidade Glenoide/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Artropatia de Ruptura do Manguito Rotador/fisiopatologia , Articulação do Ombro/diagnóstico por imagem , Tomografia Computadorizada por Raios X
4.
Maturitas ; 132: 24-29, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31883659

RESUMO

OBJECTIVE: To evaluate trabecular bone score (TBS) in Spanish postmenopausal women from our area. To analyze its relationship with bone mineral density (BMD), bone quantitative ultrasound (QUS) and serum concentrations of 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone (PTH) and bone turnover markers. STUDY DESIGN: A total of 1450 postmenopausal women aged 44-94 (62 ± 10) participated in this cross-sectional study nested in a population-based cohort. BMD and TBS were assessed by DXA. QUS measurements were performed using a Sahara Clinical Sonometer. Serum 25(OH)D, PTH, P1NP, ß-CTX were determined by electrochemiluminescence. RESULTS: Mean TBS of postmenopausal women in our region was 1.341 ± 0.111. Nearly 50 % of them had normal values. Only 11 % had scores compatible with a clearly degraded microarchitecture. TBS decreased with age, correlated negatively with BMI and was lower in current smokers than in non-smokers. An association was observed between TBS and QUS, although the association was weak and lower than that found between TBS and BMD or QUS and BMD. No association was found between TBS and 25(OH)D, PTH or bone turnover markers. CONCLUSIONS: Half of postmenopausal women in our region have TBS values that indicate a preserved microarchitecture. Only about 10 % have scores compatible with a clearly degraded microarchitecture. A weak association was observed between TBS and QUS, suggesting that the two techniques capture different aspects of bone microarchitecture. The absence of association with 25(OH)D, PTH, and bone turnover markers may be due to the fact that TBS assesses a specific (mostly trabecular) part of the skeleton, whilst the three serum factors are related to the whole skeleton.


Assuntos
Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Pós-Menopausa , Absorciometria de Fóton , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Colágeno Tipo I/sangue , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Fragmentos de Peptídeos/sangue , Peptídeos/sangue , Pós-Menopausa/sangue , Pró-Colágeno/sangue , Espanha , Ultrassonografia , Vitamina D/análogos & derivados , Vitamina D/sangue
5.
Life Sci ; 237: 116890, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606379

RESUMO

AIMS: Telmisartan (TEL), an angiotensin II type I receptor blocker and PPARγ partial agonist, has been used for to treat hypertension. It is known that PPARγ activation induces bone loss. Therefore, we evaluate the effects of telmisartan on PPARγ protein expression, biomechanics, density and bone microarchitecture of femurs and lumbar vertebrae in SHR ovariectomized animals, a model of hypertension in which preexisting bone impairment has been demonstrated. MAIN METHODS: SHR females (3 months old) were distributed into four groups: sham (S), sham + TEL (ST), OVX (C) and OVX + TEL (CT). TEL (5 mg/kg/day) or vehicle were administered according to the groups. After the protocol, blood pressure was measured and density, microarchitecture and biomechanics of bone were analyzed. Western blotting analysis was performed to evaluate PPARγ protein expression in the bones. KEY FINDINGS: Castration induced a deleterious effect on mineral density and trabecular parameters, with telmisartan enhancing such effects. Telmisartan increased PPARγ levels, which were at their highest when the treatment was combined with castration. As to biomechanical properties, telmisartan reduced the stiffness in the castration group (CT vs. S or C group), as well as resilience and failure load in ST group (vs. all others groups). SIGNIFICANCE: These results demonstrated that telmisartan compromised bone density and microarchitecture in animals that shows preexisting osteoporotic bone disorders, probably via mechanisms associated with increased PPARγ. If this translates to humans, a need for greater caution in the use of telmisartan by patients that have preexisting bone problems, as in the postmenopausal period, may be in order.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Doenças Ósseas/tratamento farmacológico , Osso Esponjoso/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Osteoporose/tratamento farmacológico , PPAR gama/metabolismo , Telmisartan/farmacologia , Animais , Densidade Óssea/efeitos dos fármacos , Doenças Ósseas/metabolismo , Doenças Ósseas/fisiopatologia , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/patologia , Feminino , Osteoporose/metabolismo , Osteoporose/fisiopatologia , PPAR gama/genética , Ratos , Ratos Endogâmicos SHR , Tomografia Computadorizada por Raios X
6.
Comput Methods Biomech Biomed Engin ; 22(16): 1258-1268, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31509022

RESUMO

Quantitative computed tomography-based finite element (QCT-FE) modeling has potential to clarify the role of altered subchondral bone stiffness in osteoarthritis. The objective of this research was to evaluate different QCT-FE modeling and thresholding approaches to identify the method which best predicted experimentally measured local subchondral structural stiffness with highest explained variance and least error. Our results showed that separate modeling of proximal tibial cortical and trabecular bone offered little improvement in QCT-FE-predicted stiffness (0% to +3% improvement in explained variance) when compared to modeling the proximal tibia as a single structure. Based on the results of this study, we do not recommend separate modeling of cortical bone and trabecular bone when developing QCT-FE models of the proximal tibia for predicting subchondral bone stiffness.


Assuntos
Osso Esponjoso/fisiologia , Osso Cortical/fisiologia , Análise de Elementos Finitos , Modelos Biológicos , Tíbia/fisiologia , Idoso , Fenômenos Biomecânicos , Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Osso Cortical/diagnóstico por imagem , Feminino , Humanos , Modelos Lineares , Masculino , Tíbia/diagnóstico por imagem , Tomografia Computadorizada por Raios X
7.
BMC Pharmacol Toxicol ; 20(1): 38, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262364

RESUMO

BACKGROUND: This study aimed to examine femoral bone microstructure of mice after single and simultaneous administration to acrylamide and ethanol since both substances are often consumed separately and/or together by humans. Interactive effects of these toxins were analysed after one remodeling cycle. METHODS: Twenty clinically healthy adult mice were randomly divided into four groups following 2 weeks administration of toxins: A group - mice were fed with acrylamide (40 mg/kg bw); E group - mice were ethanol-fed (15% ethanol); AE group - mice were simultaneously fed with both toxins, and a C group - control (without acrylamide and/or ethanol supplementation). Generally, 2D and 3D imaging methods were used to determine cortical and trabecular bone tissues microstructure. Biochemical analyses of plasma parameters were also realized using commercially available ELISA tests and spectrophotometrically. RESULTS: Single and simultaneous exposure to acrylamide and ethanol affected only cortical bone microstructure. No significant changes in trabecular bone morphometry were detected among all groups. In mice from the A group, increased endocortical remodeling associated with a higher level of serum calcium and vasoconstriction of primary osteon's vascular canals (POVC) were identified. On the contrary, increased cortical porosity consistent with a decreased relative bone volume, bone mineral density (BMD) and lower levels of alkaline phosphatase (ALP), glutathione (GSH), calcium in plasma and also with vasodilation of POVC were observed in the E group. In the AE group, the highest density of secondary osteons associated with a lower BMD and decreased levels of ALP, GSH were documented. The parameters of POVC and Haversian canals approximated to the C group. In addition, single and simultaneous exposure to both toxins caused liver disease consistent with a higher values of alanine aminotransferase (ALT), aspartate aminotransferase (AST) in plasma of all experimental groups. CONCLUSIONS: Single administration to acrylamide and ethanol had negative effects on cortical bone structure of mice after one remodeling cycle. However, we identified possible antagonistic impact of these toxins on the structure of the cortical bone.


Assuntos
Acrilamida/toxicidade , Osso Cortical/efeitos dos fármacos , Etanol/toxicidade , Fêmur/efeitos dos fármacos , Animais , Remodelação Óssea , Osso Esponjoso/anatomia & histologia , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/efeitos dos fármacos , Osso Cortical/diagnóstico por imagem , Osso Cortical/patologia , Interações Medicamentosas , Fêmur/diagnóstico por imagem , Fêmur/patologia , Masculino , Camundongos , Microtomografia por Raio-X
8.
Niger J Clin Pract ; 22(7): 982-987, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31293265

RESUMO

Background: Primary and long-term implant stabilities are crucial in predicting the success of dental implants. We aimed to evaluate corticocancellous ratio (CCR) around virtual implant using cone beam computed tomography (CT) and assess its relationship with immediate and long-term stability of the implants placed. Materials and Methods: A total of 135 image records of posterior mandibular implant sites planned for dental implant were included in our study. CCR was calculated using CT images and implants were placed after stent preparation. Implant stability was calculated immediately, 4 months later, and 2 years later. Results: Pearson's correlation test showed a significant correlation (P and lt; 0.001) between CCR and implant stability. ANOVA and post-hoc Tukey tests showed a significant difference in implant stability between groups with different CCRs at all follow-up timepoints. No significant difference was found between mean implant stability quotient values for low CCR at 2-year follow-up and high CCR immediately after implant placement. Conclusions: Implant stability is improved with greater CCR. Cortical bone seems to be crucial factor for immediate and long-term stability of a dental implant. Virtual planning using CT can assess implant stability. Further histological studies are required to confirm the relation between CCR and implant stability. The escalating demand of the implant treatment in the dental practice necessitates measuring the several predictors of procedure success. This study introduces a novel predictor (CCR) around virtual implant for detecting the immediate and long-term stability of a dental implant.


Assuntos
Osso Esponjoso/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Osso Cortical/diagnóstico por imagem , Implantes Dentários , Adulto , Feminino , Humanos , Masculino , Mandíbula/diagnóstico por imagem , Estudos Prospectivos , Tomografia Computadorizada por Raios X
9.
Radiología (Madr., Ed. impr.) ; 61(3): 225-233, mayo-jun. 2019. ilus, tab, graf
Artigo em Espanhol | IBECS | ID: ibc-185294

RESUMO

Antecedentes y objetivo: Existe una carencia de métricas cuantitativas de la calidad del hueso trabecular alveolar, factor determinante en implantología. El objetivo de este estudio es desarrollar una metodología con tomografía computarizada multidetector para objetivar la calidad del hueso trabecular y establecer diferencias entre los distintos tipos y el estado de las piezas dentarias mediante procesado de imágenes y análisis estructural. Materiales y métodos: Se analizan 20 pacientes con exploración de tomografía computarizada multidetector dental para la valoración del hueso mandibular y posiciones dentales. El análisis de las imágenes incluyó la segmentación automática de la mandíbula, obtención de secciones perpendiculares a la arcada dentaria y análisis estructural del hueso trabecular de cada sección. Se obtuvieron la ratio entre volumen de hueso y volumen total de la sección, el grosor, la separación y el número trabecular, y la atenuación promedio en unidades Hounsfield. Se analizaron diferencias entre tipos de diente (incisivos, caninos, premolares y molares) y entre estados de las piezas dentarias (ausente o presente). Resultados: Se obtuvieron diferencias estadísticamente significativas entre los tipos y estados de las piezas. Por tipo, los incisivos mostraron mayor ratio de hueso trabecular, con disminución progresiva para caninos, premolares y molares. Por estado, las secciones pertenecientes a dientes ausentes presentaron mayor ratio de hueso que con el diente presente. Conclusiones: La metodología desarrollada permite cuantificar las propiedades estructurales del hueso alveolar a partir de imágenes de tomografía computarizada multidetector. Los resultados obtenidos objetivan el estado del sustrato óseo de cara a la planificación y seguimiento de la colocación de implantes dentales


Background and objective: There is a lack of quantitative measures of the quality of alveolar trabecular bone, an important factor in implantology. This study aimed to develop a method of objectively assessing the quality of trabecular bone by means of image processing and structural analysis of multidetector computed tomography images and to establish differences between tooth types and tooth presence/absence. Materials and methods: We analyzed 20 patients who underwent multidetector computed tomography to evaluate mandibular bone and tooth positioning. Image analysis included automatic segmentation of the mandible, obtainment of sections perpendicular to the dental arch, and structural analysis of the trabecular bone in each section. We calculated the ratio between the volume of bone and the total volume of the section, the thickness, the trabecular number, and the mean attenuation in Hounsfield units. We analyzed the differences among different tooth types (incisors, canines, premolars, and molars) and between present and absent teeth. Results: We found statistically significant differences between different tooth types and between sections in which teeth were present or absent. Incisors had a greater ratio of trabecular bone; the ratio of trabecular bone progressively decreased from the incisors to the canines, premolars, and molars. The ratio of trabecular bone was greater in sections in which teeth were absent than in those in which teeth were present. Conclusions: The method allows to quantify the structural properties of alveolar bone from multidetector computed tomography images. Our results provide an objective picture of the bone substrate that can be useful for planning and following up dental implant procedures


Assuntos
Humanos , Tomografia Computadorizada Multidetectores/métodos , Osso Esponjoso/diagnóstico por imagem , Mandíbula/diagnóstico por imagem , Implantação Dentária Endo-Óssea/métodos , Cuidados Pré-Operatórios/métodos , Diagnóstico Pré-Implantação/métodos , Estudos Retrospectivos
10.
Osteoporos Int ; 30(8): 1655-1662, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31044263

RESUMO

This cross-sectional study examined the associations between c-terminal FGF23 levels, laboratory markers of bone metabolism and bone microarchitecture in 82 patients with osteoporosis. Higher FGF23 levels were associated with impaired trabecular but not cortical bone microarchitecture, and this was confirmed after adjusting for confounding variables such as age or BMI. INTRODUCTION: Fibroblast growth factor 23 (FGF23) is an endocrine hormone-regulating phosphate and vitamin D metabolism. While its mode of action is well understood in diseases such as hereditary forms of rickets or tumor-induced osteomalacia, the interpretation of FGF23 levels in patients with osteoporosis with regard to bone microarchitecture is less clear. METHODS: C-terminal FGF23 levels and bone turnover markers were assessed in 82 patients with osteoporosis (i.e., DXA T-score ≤ - 2.5 at the lumbar spine or total hip). Bone microarchitecture was measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and tibia. Data were analyzed in a cross-sectional design using correlation and regression models. RESULTS: We found a significant negative logarithmic correlation between FGF23 levels and trabecular but not cortical bone microarchitecture at both skeletal sites. Furthermore, using a multiple linear regression model, we confirmed FGF23 as a predictor for reduced trabecular parameters even when adjusting for confounding factors such as age, BMI, phosphate, bone-specific alkaline phosphatase, vitamin D3, and PTH. CONCLUSIONS: Taken together, high FGF23 levels are associated with impaired trabecular bone microarchitecture in osteoporosis patients, and this association seems to occur after adjustment of confounding variables including phosphate and vitamin D. Future longitudinal studies are now needed to validate our findings and investigate FGF23 in relation to fracture risk.


Assuntos
Osso Esponjoso/fisiopatologia , Fatores de Crescimento de Fibroblastos/sangue , Osteoporose/sangue , Absorciometria de Fóton/métodos , Idoso , Biomarcadores/sangue , Densidade Óssea/fisiologia , Remodelação Óssea/fisiologia , Osso Esponjoso/diagnóstico por imagem , Estudos Transversais , Feminino , Articulação do Quadril/diagnóstico por imagem , Articulação do Quadril/fisiopatologia , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Osteoporose/diagnóstico por imagem , Osteoporose/fisiopatologia , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/fisiopatologia , Tíbia/diagnóstico por imagem , Tíbia/fisiopatologia , Tomografia Computadorizada por Raios X/métodos
11.
Phys Rev E ; 99(4-1): 042406, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31108725

RESUMO

Trabecular bone is a lightweight, compliant material organized as a web of struts and rods (trabeculae) that erode with age and the onset of bone diseases like osteoporosis, leading to increased fracture risk. The traditional diagnostic marker of osteoporosis, bone mineral density (BMD), has been shown in ex vivo experiments to correlate poorly with fracture resistance when considered on its own, while structural features in conjunction with BMD can explain more of the variation in trabecular bone strength. We develop a network-based model of trabecular bone by creating graphs from micro-computed tomography images of human bone, with weighted links representing trabeculae and nodes representing branch points. These graphs enable calculation of quantitative network metrics to characterize trabecular structure. We also create finite element models of the networks in which each link is represented by a beam, facilitating analysis of the mechanical response of the bone samples to simulated loading. We examine the structural and mechanical properties of trabecular bone at the scale of individual trabeculae (of order 0.1 mm) and at the scale of selected volumes of interest (approximately a few mm), referred to as VOIs. At the VOI scale, we find significant correlations between the stiffness of VOIs and 10 different structural metrics. Individually, the volume fraction of each VOI is most strongly correlated to the stiffness of the VOI. We use multiple linear regression to identify the smallest subset of variables needed to capture the variation in stiffness. In a linear fit, we find that node degree, weighted node degree, Z-orientation, weighted Z-orientation, trabecular spacing, link length, and the number of links are the structural metrics that are most significant (p<0.05) in capturing the variation of stiffness in trabecular networks.


Assuntos
Osso Esponjoso/metabolismo , Modelos Moleculares , Fenômenos Biomecânicos , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/fisiologia , Humanos , Microtomografia por Raio-X
12.
J Orthop Res ; 37(8): 1784-1789, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30977552

RESUMO

Legg-Calve-Perthes disease is characterized by the capital femoral epiphyseal collapse, which occurs more reliably in the anterior quadrant than the more weight-bearing lateral quadrant. The purpose of this study was to determine whether there is a vascular or microstructural predisposition for anterior femoral epiphyseal collapse in Perthes disease. Thirty-two cadaveric proximal femoral epiphyses from 17 subjects (age 4-14 years old) underwent micro-computed tomography at 10-µm resolution. Each quadrant was analyzed for four markers of trabecular architecture: bone volume fraction (BV/TV), trabecular thickness, trabecular separation (TbSp), and trabecular number (TbN). Vascular channels were then mapped in each quadrant, identified by correlating surface topography with cross-sectional imaging. One-way analysis of variance revealed an overall difference between quadrants (p < 0.001) in BV/TV, TbN, and TbSp. However, post hoc analysis revealed there was no significant difference between the anterior and lateral quadrants for any of the four markers of trabecular architecture. Vascular channel mapping illustrated a predominance of vessels in the posterior half of the epiphysis compared to the anterior half (8.7 ± 4.0 vs. 3.4 ± 3.1 vascular channels, p < 0.001). The lack of microstructural differences between the anterior and lateral quadrants, and the predominance of vascular channels in the posterior half of the epiphysis with posteriorly-based medial femoral circumflex and ligamentum teres vessels suggests that the anterior femoral epiphysis may be a relative vascular watershed region, which predisposes it to collapse after the vascular insult of Perthes disease. Clinical significance: Improved understanding of the pathophysiology of anterior femoral epiphyseal collapse may inform future treatments aimed at revascularization. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1784-1789, 2019.


Assuntos
Osso Esponjoso/patologia , Fêmur/patologia , Doença de Legg-Calve-Perthes/patologia , Adolescente , Osso Esponjoso/irrigação sanguínea , Osso Esponjoso/diagnóstico por imagem , Criança , Pré-Escolar , Epífises/irrigação sanguínea , Epífises/diagnóstico por imagem , Epífises/patologia , Feminino , Fêmur/irrigação sanguínea , Fêmur/diagnóstico por imagem , Humanos , Doença de Legg-Calve-Perthes/diagnóstico por imagem , Masculino , Microtomografia por Raio-X
13.
Int J Mol Sci ; 20(8)2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31027235

RESUMO

Chronic kidney disease-mineral bone disorder (CKD-MBD), comprising mineral, hormonal, and bone metabolic imbalance, is a major CKD-related issue; it causes osteoporosis prevalence in CKD patients. Osteocyte-derived sclerostin inhibits the osteogenic Wnt/ß-catenin signaling pathway; its levels rise when kidney function declines. Exercise modulates the physiological functions of osteocytes, potentially altering sclerostin production. It may aid bone and mineral electrolyte homeostasis in CKD. Mild CKD was induced in rats by partial nephrectomy. They were divided into: sham (no CKD), CKD, and CKD + exercise (8 weeks of treadmill running) groups. Micro-CT scanning demonstrated that the CKD + exercise-group rats had a higher bone mineral density (BMD) of the spine and femoral metaphysis and higher femoral trabecular bone volume than the CKD-group rats. Bone formation rates were not significantly different. The CKD + exercise-group rats had lower serum sclerostin (157.1 ± 21.1 vs 309 ± 38.1 pg/mL, p < 0.05) and CTX-1 (bone resorption marker) levels. Immunohistochemistry revealed higher tibial ß-catenin concentrations in the CKD + exercise-group rats. Serum FGF-23, intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), calcium, and phosphate levels showed no significant differences between these groups. Thus, exercise improves BMD and bone microstructure in mild CKD by inhibiting sclerostin production, but does not alter serum minerals.


Assuntos
Proteínas Morfogenéticas Ósseas/biossíntese , Osteoporose/complicações , Osteoporose/prevenção & controle , Condicionamento Físico Animal , Insuficiência Renal Crônica/complicações , Animais , Biomarcadores/sangue , Biomarcadores/urina , Densidade Óssea , Proteínas Morfogenéticas Ósseas/sangue , Proteínas Morfogenéticas Ósseas/metabolismo , Reabsorção Óssea/sangue , Reabsorção Óssea/patologia , Reabsorção Óssea/fisiopatologia , Reabsorção Óssea/urina , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/patologia , Marcadores Genéticos , Rim/patologia , Rim/fisiopatologia , Masculino , Tamanho do Órgão , Osteócitos/metabolismo , Osteoporose/sangue , Osteoporose/urina , Ratos Sprague-Dawley , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/fisiopatologia , Insuficiência Renal Crônica/urina , Tíbia/patologia , beta Catenina/metabolismo
14.
PLoS One ; 14(3): e0213440, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30897099

RESUMO

INTRODUCTION: Increased prevalence of low bone mineral density (BMD) and increased fracture incidence are observed in persons living with HIV (PLWH). The trabecular bone score (TBS) is a novel index of bone microarchitecture which improves fracture prediction independent of BMD. METHODS: The HIV UPBEAT study is a single centre, prospective cohort study that enrolled subjects with and without HIV from similar sociodemographic backgrounds for annual assessments of bone health. TBS was derived from lumbar spine (LS) dual-energy X-ray absorptiometry images. Univariate and multivariable linear regression was used to assess relationships between baseline TBS, BMD, sociodemographic and clinical factors. RESULTS: 463 subjects (201 HIV positive) were included; PLWH were younger and more likely male, of non-African ethnicity and current smokers. HIV was associated with a mean reduction of 0.037 [-0.060, -0.013] (p = 0.002) in TBS. Lower TBS was also associated with male gender, non-African ethnicity, current smoking status and lower LS BMD. HIV remained associated with lower TBS after adjustment for LS BMD, age, gender and ethnicity. However, adjustment for current smoking significantly attenuated the association between HIV and TBS, with further adjustment for higher bone turnover markers largely explaining any residual association. Among the sub-group of PLWH, exposure to protease inhibitors and lower nadir CD4+ T-cell counts were both predictors of lower TBS. CONCLUSIONS: PLWH have lower TBS independent of LS BMD. However, this is largely explained by higher current smoking rates and higher bone turnover in those with HIV. Exposure to PI, but not tenofovir disproxil fumarate, also contributed to lower TBS in those with HIV.


Assuntos
Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Infecções por HIV/diagnóstico por imagem , Absorciometria de Fóton , Adulto , Estudos de Coortes , Feminino , Fraturas Ósseas/etiologia , Infecções por HIV/complicações , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Fumar/efeitos adversos
15.
J Orthop Res ; 37(5): 1153-1163, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30839119

RESUMO

Reduced mechanical loading can lead to disuse osteoporosis, resulting in bone fragility. Disuse models report macroscopic bone loss due to muscle inactivity and immobilization, yet only recently has there been quantification of the effects of disuse on the vascular pores and osteocyte network, which are believed to play an important role in mechanotransduction via interstitial fluid flow. The goal of this study was to perform a high-resolution analysis of the effects of muscle inactivity on intracortical porosity and osteocyte lacunar density in skeletally mature rats. Muscle paralysis was induced in 20-week-old female Sprague Dawley rats by injection of botulinum neurotoxin. Rats were injected in the right hindlimb muscles with either Botox (BTX, n = 8) or saline solution (CTRL, n = 8), with a third group used as baseline controls (n = 8). Four weeks after injection, Botox caused a ∼60% reduction in hindlimb muscle mass. High-resolution micro-CT analysis showed that Botox-induced muscle paralysis increased vascular canal porosity and reduced osteocyte lacunar density within the tibial metaphysis cortex. Cortical thickness and other areal properties were diminished in the proximal tibial metaphysis, whereas no differences were found in the mid-diaphysis. Within the BTX group, the injected limbs showed a lower cancellous bone volume fraction relative to the contralateral limb. These results indicate that diminished muscle activity alters the vascular canal porosity and osteocyte lacunar density in cortical bone, which could alter interstitial fluid flow, affecting molecular transport and the transmission of mechanical signals to osteocytes. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.


Assuntos
Osso Esponjoso/patologia , Osso Cortical/patologia , Paralisia/patologia , Comportamento Sedentário , Animais , Toxinas Botulínicas Tipo A , Osso Esponjoso/diagnóstico por imagem , Osso Cortical/diagnóstico por imagem , Feminino , Marcha , Imageamento Tridimensional , Osteócitos , Paralisia/fisiopatologia , Porosidade , Distribuição Aleatória , Ratos Sprague-Dawley , Microtomografia por Raio-X
16.
Horm Metab Res ; 51(3): 186-190, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30861565

RESUMO

Following a parathyroidectomy there is a bone mineral density (BMD) improvement in patients with primary hyperparathyroidism. However, data of bone microarchitecture are scarce. Trabecular bone score (TBS) estimates bone microarchitecture and could provide valuable information in those patients. The aim of this study is to assess TBS changes 2 years after successful surgery in a group of patients with primary hyperparathyroidism and correlate these results with changes in BMD and bone turnover markers. This is a prospective study including 32 patients. In all participants BMD and TBS were measured, before and 24 months after surgery. Biochemical data: serum calcium, PTH, 25-OH-vitamin D, beta-crosslaps, bone alkaline phosphatase, and osteocalcin. 25 female and 7 male patients, mean age 64.6±12.4 years, were included in the study. At baseline, BMD was low at: lumbar spine (T-score -2.19±1.31), total hip (-1.33±1.12), femoral neck (-1.75±0.84), and distal one-third radius (-2.74±1.68). Baseline TBS showed partially degraded microarchitecture (1.180±0.130). After parathyroidectomy lumbar spine BMD increased significantly (5.3±13.0%, p<0.05), as well as total hip (3.8±8.8%, p<0.05). There was an increase in TBS, but this was not significant. There was a correlation between TBS and BAP at baseline (rs=0.73; p<0.01) and TBS and BAP 2 years after surgery (rs=0.57, p<0.05). Although bone density improves 2 years after surgery in patients with primary hyperparathyroidism and there is a restoration of bone turnover markers, TBS is not completely restored. These results remark the necessity of longer periods of study, to confirm if bone microarchitecture could be completely restored after surgery.


Assuntos
Densidade Óssea/fisiologia , Cálcio/sangue , Osso Esponjoso/diagnóstico por imagem , Hiperparatireoidismo/cirurgia , Hormônio Paratireóideo/sangue , Vitamina D/análogos & derivados , Idoso , Fosfatase Alcalina/sangue , Biomarcadores/sangue , Feminino , Humanos , Hiperparatireoidismo/sangue , Hiperparatireoidismo/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Paratireoidectomia , Estudos Prospectivos , Vitamina D/sangue
17.
Nutrients ; 11(3)2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30841631

RESUMO

The Mediterranean diet (MD) has been associated with an improvement in health and an increase in longevity. Certain components of a MD can play a role in the prevention of osteoporosis and/or hip fracture. We investigated the association between the degree of adherence to a MD and bone mineral density (BMD) measured in several bone areas in a population of Spanish premenopausal women. We analyzed 442 premenopausal women aged 42.73 ± 6.67 years. Bone measurements were obtained using quantitative bone ultrasound (QUS) for the phalanx, dual energy X-ray absorptiometry (DXA) for the lumbar spine, Ward's triangle, trochanter, and hip, and peripheral quantitative computed tomography (pQCT) for the non-dominant distal forearm. MD adherence was evaluated with MedDietScore. Amplitude-dependent speed of sound (Ad-SOS), BMD, and volumetric bone mineral density (vBMD) (total, trabecular, and cortical bone density) were positively associated with higher adherence to the MD (p < 0.05). Adherence to the MD was significantly associated with QUS, BMD, and vBMD in multiple regression analysis; QUS: Ad-SOS (m/s) ß = 0.099 (p = 0.030); BMD (g/cm²): femur neck ß = 0.114 (p = 0.010) and Ward's triangle ß = 0.125 (p = 0.006); vBMD (mg/cm³): total density ß = 0.119 (p = 0.036), trabecular density ß = 0.120 (p = 0.035), and cortical density ß = 0.122 (p = 0.032). We conclude that the adherence to the MD was positively associated with better bone mass in Spanish premenopausal women.


Assuntos
Densidade Óssea/fisiologia , Dieta Mediterrânea/estatística & dados numéricos , Cooperação do Paciente/estatística & dados numéricos , Pré-Menopausa/fisiologia , Absorciometria de Fóton , Adulto , Osso Esponjoso/diagnóstico por imagem , Estudos Transversais , Dieta Mediterrânea/psicologia , Feminino , Antebraço/diagnóstico por imagem , Humanos , Vértebras Lombares/diagnóstico por imagem , Pessoa de Meia-Idade , Pré-Menopausa/psicologia , Espanha , Tomografia Computadorizada por Raios X
18.
Biomed Res Int ; 2019: 2075968, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30911541

RESUMO

Purpose: Blood vessels and skeleton interact together. Endothelin-1 is a potent vasoconstrictor and also has an effect on bone metabolism. The dual antagonist to both endothelin-1 type A and B receptors, Macitentan, has been approved for clinical management of pulmonary arterial hypertension while little is known about the secondary effect of the drug on spine. We aimed to answer how vertebral bone mass responded to Macitentan treatment in mice. Methods: Sixteen male balb/c mice at 6 months were randomly assigned into 2 groups. Vehicle and Macitentan were administrated via intraperitoneal injection to Control group and Treatment group, respectively, for 4 months. At sacrifice, plasma endothelin-1 was evaluated with ELISA and vertebral bone mass was evaluated with Microcomputed Tomography and histological analysis. Results: We found higher plasma endothelin-1 level (p<0.01) and less vertebral bone mass (p<0.05) in Treatment group compared to controls. Moreover, less osteoblasts and more osteoclasts were observed in the vertebral trabecular bone in the Treatment group compared to controls, by immunohistochemistry of the cell-specific markers. Conclusions: Treatment with Macitentan is associated with significant lower vertebral bone mass and therefore the secondary effect of dual antagonists to endothelin-1 receptors on the skeleton should be monitored and investigated in clinical practice. Both osteoblasts and osteoclasts may be involved while the molecular mechanism needs to be further explored.


Assuntos
Densidade Óssea/efeitos dos fármacos , Osso Esponjoso , Osteoblastos , Pirimidinas/efeitos adversos , Coluna Vertebral , Sulfonamidas/efeitos adversos , Animais , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/metabolismo , Endotelina-1/metabolismo , Hipertensão/tratamento farmacológico , Hipertensão/metabolismo , Hipertensão/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Osteoblastos/metabolismo , Osteoblastos/patologia , Projetos Piloto , Pirimidinas/farmacologia , Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral/metabolismo , Sulfonamidas/farmacologia
19.
Radiology ; 291(2): 360-367, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30912719

RESUMO

Background Abdominal and thoracic CT provide a valuable opportunity for osteoporosis screening regardless of the clinical indication for imaging. Purpose To establish reference normative ranges for first lumbar vertebra (L1) trabecular attenuation values across all adult ages to measure bone mineral density (BMD) at routine CT. Materials and Methods Reference data were constructed from 20 374 abdominal and/or thoracic CT examinations performed at 120 kV. Data were derived from adults (mean age, 60 years ± 12 [standard deviation]; 56.1% [11 428 of 20 374] women). CT examinations were performed with (n = 4263) or without (n = 16 111) intravenous contrast agent administration for a variety of unrelated clinical indications between 2000 and 2018. L1 Hounsfield unit measurement was obtained either with a customized automated tool (n = 11 270) or manually by individual readers (n = 9104). The effects of patient age, sex, contrast agent, and manual region-of-interest versus fully automated L1 Hounsfield unit measurement were assessed using multivariable logistic regression analysis. Results Mean L1 attenuation decreased linearly with age at a rate of 2.5 HU per year, averaging 226 HU ± 44 for patients younger than 30 years and 89 HU ± 38 for patients 90 years or older. Women had a higher mean L1 attenuation compared with men (P < .008) until menopause, after which both groups had similar values. Administration of intravenous contrast agent resulted in negligible differences in mean L1 attenuation values except in patients younger than 40 years. The fully automated method resulted in measurements that were average 21 HU higher compared with manual measurement (P < .004); at intrapatient subanalysis, this difference was related to the level of transverse measurement used (midvertebra vs off-midline level). Conclusion Normative ranges of L1 vertebra trabecular attenuation were established across all adult ages, and these can serve as a quick reference at routine CT to identify adults with low bone mineral density who are at risk for osteoporosis. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Smith in this issue.


Assuntos
Osso Esponjoso/diagnóstico por imagem , Programas de Rastreamento/métodos , Osteoporose/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste/administração & dosagem , Meios de Contraste/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia Abdominal , Radiografia Torácica , Estudos Retrospectivos , Adulto Jovem
20.
Arch Osteoporos ; 14(1): 26, 2019 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-30815747

RESUMO

Trabecular bone score (TBS) is a tool to improve evaluation of DXA scans, barely used in children. We proposed to evaluate TBS with bone age (BA) compared to chronological age (CA). In girls, TBS value using BA is constant until age 8, and in boys until age 10, and then starts to increase steadily. This data may help widen TBS use in pediatric populations. INTRODUCTION: Trabecular bone score (TBS) is a software-based tool for the analysis of DXA images to assess bone microarchitecture in the lumbar region. It is used widely in adults to improve evaluation of fracture risk, yet it has been rarely studied in children and no normal curves have been developed for pediatrics. The purpose of this study was to evaluate bone (skeletal) age compared to chronological age to determine which is better in the pediatric population since both bone age (BA) and trabecular density are equally susceptible to change in response to similar factors. METHODS: Total body, lumbar region, and non-dominant hand scans were obtained with an iDXA device in all participants. DXA scans of lumbar region for TBS analysis and AP images of non-dominant hand-for-BA were obtained for 565 children (269 female) aged 4to 19. RESULTS: Simple correlation was calculated and r2 values for TBS and chronological age were obtained by linear regression, with low correlations (0.36 for boys and 0.38 for girls), and then we created Loess curves to show the change for consecutive ages. In girls, the curve forms a U shape with a nadir point at approximately age 10. We then replaced chronological age with BA, and significant change was seen in the girls' curve, where a turning point is seen at age 8. In boys, a similar trend shows a turning point at age 10. Finally, BA-corrected TBS curves were constructed using LMS, obtaining curves with percentiles. CONCLUSIONS: The use of BA in the analysis and interpretation of TBS may help widen its use in pediatric populations by enabling the appearance of normative data, but more information is needed to confirm this finding.


Assuntos
Absorciometria de Fóton/estatística & dados numéricos , Determinação da Idade pelo Esqueleto/estatística & dados numéricos , Osso Esponjoso/diagnóstico por imagem , Absorciometria de Fóton/métodos , Adolescente , Densidade Óssea/fisiologia , Criança , Pré-Escolar , Análise Fatorial , Feminino , Mãos/diagnóstico por imagem , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiologia , Masculino , Valores de Referência , Adulto Jovem
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