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Bisazza KT, Nelson BB, Sikes KJ, Nakamura L, Easley JT. Computed Tomography Provides Improved Quantification of Trabecular Lumbar Spine Bone Loss Compared to Dual-Energy X-Ray Absorptiometry in Ovariectomized Sheep. JBMR Plus 2023; 7:e10807. [PMID: 38130759 PMCID: PMC10731101 DOI: 10.1002/jbm4.10807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/26/2023] [Accepted: 08/01/2023] [Indexed: 12/23/2023] Open
Abstract
Early detection of osteoporosis using advanced imaging is imperative to the successful treatment and prevention of high morbidity fractures in aging patients. In this preclinical study, we aimed to compare dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) to quantify bone mineral density (BMD) changes in the sheep lumbar spine. We also aimed to determine the relationship of BMD to microarchitecture in the same animals as an estimate of imaging modality precision. Osteoporosis was induced in 10 ewes via laparoscopic ovariectomy and administration of high-dose corticosteroids. We performed DXA and QCT imaging to measure areal BMD (aBMD) and trabecular volumetric BMD (Tb.vBMD)/cortical vBMD (Ct.vBMD), respectively, at baseline (before ovariectomy) and at 3, 6, 9, and 12 months after ovariectomy. Iliac crest bone biopsies were collected at each time point for micro-computed tomography (microCT) analysis; bone volume fraction (BV/TV), trabecular number (Tb.N), thickness (Tb.Th), and spacing (Tb.Sp) were reported. aBMD and Tb.vBMD both decreased significantly by 3 and 6 months (p < 0.05) compared with baseline, whereas no changes to Ct.vBMD were observed. Combined (Tb. and Ct.) vBMD was significantly correlated with aBMD at all time points (all p < 0.05). Additionally, greater significant correlations were found between BV/TV and Tb.vBMD at all five time points (R 2 = 0.54, 0.57, 0.66, 0.46, and 0.56, respectively) than with aBMD values (R 2 = 0.23, 0.55, 0.41, 0.20, and 0.19, respectively). The higher correlation of microCT values with QCT than with DXA indicates that QCT provides additional detailed information regarding bone mineral density changes in preclinical settings. Because trabecular bone is susceptible to rapid density loss and structural changes during osteoporosis, QCT can capture these subtle changes more precisely than DXA in a large animal preclinical model. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Katie T Bisazza
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityFort CollinsCOUSA
| | - Brad B Nelson
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityFort CollinsCOUSA
| | - Katie J Sikes
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityFort CollinsCOUSA
| | - Lucas Nakamura
- Orthopaedic Bioengineering Research Laboratory, Department of Mechanical EngineeringColorado State UniversityFort CollinsCOUSA
| | - Jeremiah T Easley
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityFort CollinsCOUSA
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Giavaresi G, Fini M, Torricelli P, Martini L, Giardino R. The Ovariectomized Ewe Model in the Evaluation of Biomaterials for Prosthetic Devices in Spinal Fixation. Int J Artif Organs 2018. [DOI: 10.1177/039139880102401106] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effect of surgical ovariectomy on cancellous bone was investigated by comparing mechanical properties and microarchitectural characteristics of the lumbar vertebrae in ovariectomized and sham-operated ewes. Eighteen mongrel ewes, 4±1 years old, were randomly divided into three groups: 6 animals served as a control group (Baseline), 6 were bilaterally ovariectomized (OVX), and the others were used as a sham-operated group (SHAM). OVX and SHAM ewes were euthanized 24 months after surgery; the L5 vertebrae were processed for mechanical and histomorphometric analyses. Maximum load, maximum strength (p<0.0005) and elastic modulus (p <0.005) decreased by about 28% in the OVX group in comparison with the other groups. In the OVX group, vertebral cancellous bone volume, trabecular thickness and trabecular number decreased by about 32% (p<0.0005), 15% (p=0.001) and 20% (p=0.019), respectively. An overall decrease in the bone turnover rate of the OVX group was registered in terms of bone formation rate (p= 0.007) and activation frequency (p<0.0005). The variations observed in cancellous bone mechanics and histomorphometry would suggest the development of an osteopenic state in ewe vertebrae at 24 months. Such findings may be useful for future experimental investigations on biomaterials and prosthetic devices to be implanted in the osteopenic spine.
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Affiliation(s)
- G. Giavaresi
- Department of Experimental Surgery, Rizzoli Orthopedic Institute, Bologna - Italy
| | - M. Fini
- Department of Experimental Surgery, Rizzoli Orthopedic Institute, Bologna - Italy
| | - P. Torricelli
- Department of Experimental Surgery, Rizzoli Orthopedic Institute, Bologna - Italy
| | - L. Martini
- Department of Experimental Surgery, Rizzoli Orthopedic Institute, Bologna - Italy
| | - R. Giardino
- Department of Experimental Surgery, Rizzoli Orthopedic Institute, Bologna - Italy
- Chair of Surgical Pathophysiology, University of Bologna, Bologna - Italy
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Ayyappan S, Niveditha B, Breur GJ. Determination of baseline bone mineral density using dual energy X-ray absorptiometry in Suffolk-Dorset hybrid ewes. Int J Vet Sci Med 2017; 5:41-46. [PMID: 30255047 PMCID: PMC6137841 DOI: 10.1016/j.ijvsm.2017.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/03/2017] [Accepted: 03/10/2017] [Indexed: 11/29/2022] Open
Abstract
Dual energy x-ray absorptiometry (DEXA) has the ability to rapidly and non-invasively measure bone mineral density and is the most widely accepted method for quantitative assessment of bone mineral status in vivo. There is scarce information available on the baseline bone mineral density (BMD) values in adult intact Suffolk Dorset ewes (5-7 years), a frequently used animal model for the study of post-menopausal osteoporosis. The objective of the present study was to determine the baseline bone mineral density values in 26 adult intact Suffolk-Dorset hybrid ewes using a Lunar Prodigy DPX x-ray bone densitometer. The DEXA scans of the femur, lumbar spine (L3-L6) and calcaneus were obtained. Because of the low variability between the scans for the lumbar vertebrae and calcaneus in the first two animals, only two scans were obtained for the remaining animals of the study. The femoral scans were rejected due to high variability between the scans. The BMD was calculated using the standard GE antero-posterior human spine acquisition software. The bone mineral densities of regions of interest (ROIs) were compared by the Bonferroni significant difference technique. The results of the study demonstrated that the BMD progressively reduced from L3 to L6 and a strong correlation was found between the BMD values for the ROIs from L3 to L6. The present study provided a precise and rapid method for measuring the BMD of the lumbar spine in Suffolk-Dorset breed of sheep and recorded reference values in adult sheep.
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Affiliation(s)
- Subburamanujam Ayyappan
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, IN 47907, United States
| | - Bharathi Niveditha
- Department of Veterinary Surgery and Radiology, Madras Veterinary College, Chennai 7, India
| | - Gert J Breur
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, IN 47907, United States
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Karakoyun DO, Özkaya M, Okutan VC, Dalgıç A, Belen D, Demir T. Biomechanical comparison of unilateral semi-rigid and dynamic stabilization on ovine vertebrae. Proc Inst Mech Eng H 2015; 229:778-85. [DOI: 10.1177/0954411915612493] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Using the unilateral pedicle screw fixation was thought to decrease the stiffness of the fixed segments. Various prospective, randomized studies were performed to determine whether unilateral pedicle screw fixation provides the necessities of bilateral fixation in one- or two-segment lumbar spinal fusion. In this study, four different unilateral pedicle screw fixation systems were evaluated to determine which one best approximated an intact spine with respect to biomechanics and kinematics. The four groups included an intact group, a unilateral facetectomy group with no fixation, a unilateral semi-rigid pedicle screw fixation group with a poly-ether-ether-ketone rod, and a unilateral dynamic pedicle screw fixation group. The bone mineral densities of all specimens were measured and specimens were matched with groups randomly. Flexion, lateral bending, and axial rotation tests were performed to compare the groups. For the flexion, lateral bending, and axial rotation tests, the best biomechanical outcomes were in the control group. The unilateral facetectomy group had the poorest performance and was not stable enough, compared with the control group. The dynamic and semi-rigid groups showed performance closer to that of the control group. The biomechanical responses of these two groups were also in good agreement, showing no significant statistical differences. Based on these test results, it is concluded that the unilateral dynamic and semi-rigid pedicle screw fixations can be used to provide stability to the vertebrae.
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Affiliation(s)
- Dursun O Karakoyun
- Department of Neurosurgery, Ankara Numune Education and Training Hospital, Ankara, Turkey
| | - Mustafa Özkaya
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara, Turkey
| | - Volkan C Okutan
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara, Turkey
| | - Ali Dalgıç
- Department of Neurosurgery, Ankara Numune Education and Training Hospital, Ankara, Turkey
| | - Deniz Belen
- Department of Neurosurgery, Ankara Numune Education and Training Hospital, Ankara, Turkey
| | - Teyfik Demir
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara, Turkey
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Bone mineral density (BMD) and computer tomographic measurements of the equine proximal phalanx in correlation with breaking strength. Pol J Vet Sci 2013; 16:3-8. [PMID: 23691569 DOI: 10.2478/pjvs-2013-0001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Despite the fact that bone mineral density (BMD) is an important fracture risk predictor in human medicine, studies in equine orthopedic research are still lacking. We hypothesized that BMD correlates with bone failure and fatigue fractures of this bone. Thus, the objectives of this study were to measure the structural and mechanical properties of the proximal phalanx with dual energy X-ray absorptiometry (DXA), to correlate the data obtained from DXA and computer tomography (CT) measurements to those obtained by loading pressure examination and to establish representative region of interest (ROI) for in vitro BMD measurements of the equine proximal phalanx for predicting bone failure force. DXA was used to measure the whole bone BMD and additional three ROI sites in 14 equine proximal phalanges. Following evaluation of the bone density, whole bone, cortical width and area in the mid-diaphyseal plane were measured on CT images. Bones were broken using a manually controlled universal bone crusher to measure bone failure force and reevaluated for the site of fractures on follow-up CT images. Compressive load was applied at a constant displacement rate of 2 mm/min until failure, defined as the first clear drop in the load measurement. The lowest BMD was measured at the trabecular region (mean +/- SD: 1.52 +/- 0.12 g/cm2; median: 1.48 g/cm2; range: 1.38-1.83 g/cm2). There was a significant positive linear correlation between trabelcular BMD and the breaking strength (P = 0.023, r = 0.62). The trabecular region of the proximal phalanx appears to be the only significant indicator of failure of strength in vitro. This finding should be reassessed to further reveal the prognostic value of trabecular BMD in an in vivo fracture risk model.
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Cao L, Liu G, Gan Y, Fan Q, Yang F, Zhang X, Tang T, Dai K. The use of autologous enriched bone marrow MSCs to enhance osteoporotic bone defect repair in long-term estrogen deficient goats. Biomaterials 2012; 33:5076-84. [PMID: 22504017 DOI: 10.1016/j.biomaterials.2012.03.069] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/21/2012] [Indexed: 01/10/2023]
Abstract
Bone defects are common in elderly patients suffering from osteoporosis. Current methods of bone defect treatment for osteoporosis are not always satisfactory. In this study, we demonstrated that bone marrow mesenchymal stem cells (MSCs) harvested from goats with long-term estrogen deficiencies exhibited a lower proliferation rate and decreased osteogenic capacity, which are critical obstacles for bone defect repair in the elderly. However, by combining autologous enriched bone marrow mesenchymal stem cells with porous β-TCP, we successfully repaired critical-sized bone defects in the medial femoral condyle of the osteoporotic goats. Both micro-CT images and histomorphometry analysis illustrated improved bone formation following the enriched MSC therapy. Thus, we proposed autologous enriched bone marrow mesenchymal stem cells as a quick, safe therapeutic strategy to treat osteoporotic bone defects.
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Affiliation(s)
- Lei Cao
- Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
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Moran JM, Lavado-Garcia JM, Pedrera-Zamorano JD. Methods for nurses to measure body composition. Rev Lat Am Enfermagem 2011; 19:1033-8. [DOI: 10.1590/s0104-11692011000400024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 03/04/2011] [Indexed: 11/22/2022] Open
Abstract
Among the methods available for assessing body composition, traditional methods like hydrodensitometry and skin-fold measurements are well known. In this review, we focus on the impedance and interactance methods, which use systems that are usually inexpensive, easily transportable and simple to operate. We also discuss the usefulness of dual energy X-ray absorptiometry, particularly for the measurement of fat distribution. Nurses need to be skilled in the use of the equipment and familiar with the techniques.
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Meller R, Neddermann A, Willbold E, Hesse E, Haasper C, Singh A, Knobloch K, Krettek C, Hankemeier S. The relation between tunnel widening and bone mineral density after anterior cruciate ligament reconstruction: an experimental study in sheep. Arthroscopy 2010; 26:481-7. [PMID: 20362826 DOI: 10.1016/j.arthro.2009.08.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/30/2009] [Accepted: 08/30/2009] [Indexed: 02/02/2023]
Abstract
PURPOSE The aim of this study was to analyze the relation between bone mineral density (BMD) and femoral tunnel enlargement (TE) in a previously validated sheep model of soft-tissue anterior cruciate ligament (ACL) reconstruction. METHODS Thirty sheep underwent ACL reconstruction by use of a soft-tissue graft at the age of 4 months. Graft fixation was achieved with the EndoButton (Smith & Nephew Endoscopy, Andover, MA) and Suture Washer (Smith & Nephew Endoscopy). Six animals were killed at 0, 3, 6, 12, and 24 weeks postoperatively. Each ACL-reconstructed knee was examined both by computed tomography to analyze the bone tunnel cross-sectional area and by dual-energy x-ray absorptiometry to analyze BMD. RESULTS There was a significant increase in tunnel cross-sectional area. BMD decreased significantly within the first 3 weeks after surgery and increased thereafter. A positive correlation between TE and BMD was found. However, a subgroup analysis showed that there is no influence of BMD on the development of a tunnel widening. CONCLUSIONS The hypothesis that a TE would be associated with a loss in BMD was not confirmed. Tunnel widening during the first 6 months after ACL reconstruction is not affected by the transient changes in BMD. CLINICAL RELEVANCE There is no correlation between TE and BMD in an experimental sheep model of ACL reconstruction. Translational investigations will determine whether this is also true in humans.
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Affiliation(s)
- Rupert Meller
- Trauma Department, Hannover Medical School, Hannover, Germany.
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Castañeda S, Largo R, Calvo E, Rodríguez-Salvanés F, Marcos ME, Díaz-Curiel M, Herrero-Beaumont G. Bone mineral measurements of subchondral and trabecular bone in healthy and osteoporotic rabbits. Skeletal Radiol 2006; 35:34-41. [PMID: 16247642 DOI: 10.1007/s00256-005-0022-z] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 06/06/2005] [Accepted: 08/01/2005] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Experimental models of osteoporosis in rabbits are useful to investigate anabolic agents because this animal has a fast bone turnover with predominant remodelling over the modelling processes. For that purpose, it is necessary to characterize the densitometric values of each type of bony tissue. OBJECTIVE To determine areal bone mass measurement in the spine and in trabecular, cortical and subchondral bone of the knee in healthy and osteoporotic rabbits. DESIGN Bone mineral content and bone mineral density were measured in lumbar spine, global knee, and subchondral and cortical bone of the knee with dual energy X-ray absorptiometry using a Hologic QDR-1000/W densitometer in 29 skeletally mature female healthy New Zealand rabbits. Ten rabbits underwent triplicate scans for evaluation of the effect of repositioning. Osteoporosis was experimentally induced in 15 rabbits by bilateral ovariectomy and postoperative corticosteroid treatment for 4 weeks. Identical dual energy X-ray absorptiometry (DXA) studies were performed thereafter. RESULTS Mean values of bone mineral content at the lumbar spine, global knee, subchondral bone and cortical tibial metaphysis were: 1934+/-217 mg, 878+/-83 mg, 149+/-14 mg and 29+/-7.0 mg, respectively. The mean values of bone mineral density at the same regions were: 298+/-24 mg/cm(2), 455+/-32 mg/cm(2), 617+/-60 mg/cm(2) and 678+/-163 mg/cm(2), respectively. Bone mineral content and bone density of healthy rabbits followed a normal distribution at the four skeletal regions studied. Precision after triplicate repositioning yielded a coefficient of variation ranging from 2.6% to 3.8%. The least significant change ranged between 7.3% and 10.7%. Bone mineral density measured at the four different skeletal regions correlated significantly. Bone mineral density in osteoporotic rabbits was significantly lower in the four regions studied than that in controls, rendering a T-score of, respectively, -2.0+/-1.1 in the lumbar spine, -2.2+/-2.1 in the global knee, -1.9+/-0.6 in the subchondral bone, and -5.7+/-3.1 in the cortical tibia (P<0.05). CONCLUSIONS DXA is a reliable and precise method to evaluate the bone mass in rabbits. Our results also suggest that subchondral bone is a bone of mixed densitometric characteristics with marked cortical bone predominance.
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Affiliation(s)
- S Castañeda
- Rheumatology Department, Hospital de la Princesa, Universidad Autónoma, Madrid, Spain
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Ekici H, Sontas BH, Toydemir TSF, Senmevsim O, Kabasakal L, Imre Y. Effect of prepubertal ovariohysterectomy on bone mineral density and bone mineral content in puppies. Acta Vet Hung 2005; 53:469-78. [PMID: 16363148 DOI: 10.1556/avet.53.2005.4.7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study, dual energy X-ray absorptiometry (DXA) was performed on the calcaneus (CAL) and accessory carpal bone (ACB) of early-age neutered (n = 11) and sham-operated puppies (n = 10) to investigate changes in bone mineral density (BMD) and bone mineral content (BMC) over time. Prepubertal ovariohysterectomy and sham surgery were performed at 10 weeks, while BMD and BMC were measured at 12, 16, 20 and 24 weeks of age. BMD and BMC of CAL and ACB of ovariohysterectomised puppies were found to be higher. The differences between the groups were statistically unimportant; however, the fourth measurement of the ACB showed a significant (P < 0.05) difference. Sexually intact puppies weighed less than gonadectomised puppies in all measurements. Because of the positive correlations between body weight and bone mineral density, BMD and BMC of early-age neutered puppies were found to be higher. These results suggest that BMD and BMC are not affected by prepubertal ovariohysterectomy until six months of age in mixed-breed puppies.
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Affiliation(s)
- H Ekici
- Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Istanbul University, Avcilar, Turkey.
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Carstanjen B, Duboeuf F, Detilleux J, Lepage OM. Equine third metacarpal bone assessment by quantitative ultrasound and dual energy X-ray absorptiometry: an ex vivo study. JOURNAL OF VETERINARY MEDICINE. A, PHYSIOLOGY, PATHOLOGY, CLINICAL MEDICINE 2003; 50:42-7. [PMID: 12650508 DOI: 10.1046/j.1439-0442.2003.00495.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The purpose of this ex vivo study was to analyse two commonly established methods of mechanical bone property assessment for application in horses: Quantitative ultrasound (QUS), which depends on the bone's density and Young's modulus, and dual energy X-ray absorptiometry (DXA), which depends on the areal bone mineral density (BMD). The third metacarpal bone (MC III) of horses was selected as examination region for practical reasons. An interrelationship between QUS- and DXA-values was examined. Both MC III of eleven randomly selected equine cadavers were divided in nine regions of interest (ROI). A multi-site QUS device was used for axial transmission speed of sound (SOS) measurements and a DXA device was used for BMD evaluation. Full cortical thickness BMD (FcBMD), overall aspect BMD and 4 mm cortical border slice BMD (4 mmBMD) were evaluated. In addition, each ROI of one MC III was measured 10 times to determine QUS- and DXA-measurement precision. SOS values and BMD values obtained at different aspects of MC III were different (P < 0.001). FcBMD and overall BMD obtained at different levels were different (P < 0.001). SOS data correlated with FcBMD-, overall BMD- and 4 mmBMD-data at various ROI. FcBMD-, overall BMD- and 4 mmBMD-data were strongly correlated. The intra-operator coefficient of variation was 1.3% for SOS-measurements and ranged between 1.94 and 10.3% for BMD-measurements. Multi-site axial transmission QUS as well as DXA can be used to precisely measure bone characteristics of MC III in horses. However, both techniques do not measure the same bone properties. It is therefore concluded, that QUS and DXA techniques are complementary for application in horses.
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Affiliation(s)
- B Carstanjen
- Département Hippique, Ecole Nationale Vétérinaire de Lyon, Marcy l'Etoile, France.
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Abstract
There is great interest in large animal models for studying different aspects of osteoporosis. Several laboratories around the world have used ovariectomized sheep as a model because of their ease of housing and handling, low expense compared to other large animals, availability and acceptance in society as a research animal. They have been used to study the response to new therapies for post-menopausal osteoporosis, low-magnitude mechanical stimulation, orthopedic implants in osteoporotic bone and bioactive ceramics to strengthen vertebral bodies. To produce severely osteopenic bone comparable to that seen in humans, a combination of estrogen deficiency following ovariectomy plus a calcium-wasting diet is currently being investigated.
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Affiliation(s)
- A S Turner
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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Rubin C, Turner AS, Mallinckrodt C, Jerome C, McLeod K, Bain S. Mechanical strain, induced noninvasively in the high-frequency domain, is anabolic to cancellous bone, but not cortical bone. Bone 2002; 30:445-52. [PMID: 11882457 DOI: 10.1016/s8756-3282(01)00689-5] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Departing from the premise that it is the large-amplitude signals inherent to intense functional activity that define bone morphology, we propose that it is the far lower magnitude, high-frequency mechanical signals that continually barrage the skeleton during longer term activities such as standing, which regulate skeletal architecture. To examine this hypothesis, we proposed that brief exposure to slight elevations in these endogenous mechanical signals would suffice to increase bone mass in those bones subject to the stimulus. This was tested by exposing the hind limbs of adult female sheep (n = 9) to 20 min/day of low-level (0.3g), high-frequency (30 Hz) mechanical signals, sufficient to induce a peak of approximately 5 microstrain (micro epsilon) in the tibia. Following euthanasia, peripheral quantitative computed tomography (pQCT) was used to segregate the cortical shell from the trabecular envelope of the proximal femur, revealing a 34.2% increase in bone density in the experimental animals as compared with controls (p = 0.01). Histomorphometric examination of the femur supported these density measurements, with bone volume per total volume increasing by 32% (p = 0.04). This density increase was achieved by two separate strategies: trabecular spacing decreased by 36.1% (p = 0.02), whereas trabecular number increased by 45.6% (p = 0.01), indicating the formation of cancellous bone de novo. There were no significant differences in the radii of animals subject to the stimulus, indicating that the adaptive response was local rather than systemic. The anabolic potential of the signal was evident only in trabecular bone, and there were no differences, as measured by any assay, in the cortical bone. These data suggest that subtle mechanical signals generated during predominant activities such as posture may be potent determinants of skeletal morphology. Given that these strain levels are three orders of magnitude below strains that can damage bone tissue, we believe that a noninvasive stimulus based on this sensitivity has potential for treating skeletal complications such as osteoporosis.
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Affiliation(s)
- C Rubin
- Musculo-Skeletal Research Laboratory, Department of Biomedical Engineering, State University of New York, Stony Brook, NY 11794-2580, USA.
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