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Coulombe JC, Johannesdottir F, Burkhart KA, Brummer H, Allaire BT, Bouxsein ML. Changes in Vertebral Bone Density and Paraspinal Muscle Morphology Following Spaceflight and 1 Year Readaptation on Earth. JBMR Plus 2023; 7:e10810. [PMID: 38130751 PMCID: PMC10731107 DOI: 10.1002/jbm4.10810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 06/30/2023] [Accepted: 08/07/2023] [Indexed: 12/23/2023] Open
Abstract
Astronauts have an increased risk of back pain and disc herniation upon returning to Earth. Thus, it is imperative to understand the effects of spaceflight and readaptation to gravity on the musculoskeletal tissues of the spine. Here we investigated whether ~6 months of spaceflight led to regional differences in bone loss within the vertebral body. Additionally, we evaluated the relationships between vertebral bone density and paraspinal muscle morphology before flight, after flight, and after readaptation on Earth. We measured vertebral trabecular bone mineral density (Tb.BMD), paraspinal muscle cross-sectional area (CSA), and muscle density in 17 astronauts using computed tomography (CT) images of the lumbar spine obtained before flight (before flight, n = 17), after flight (spaceflight, n = 17), and ~12 months of readaptation to gravitational loading on Earth (follow-up, n = 15). Spaceflight-induced declines in Tb.BMD were greater in the superior region of the vertebral body (-6.7%) than the inferior (-3.1%, p = 0.052 versus superior region) and transverse regions (-4.3%, p = 0.057 versus superior region). After a year of readaptation to Earth's gravity, Tb.BMD in the transverse region remained significantly below preflight levels (-4.66%, p = 0.0094). Paraspinal muscle CSA and muscle density declined -1.0% (p = 0.005) and -0.83% (p = 0.001) per month of spaceflight, respectively. Ultimately, bone loss in the superior vertebral body, along with fatty infiltration of paraspinal muscles and incomplete recovery even after a year of readaptation on Earth, may contribute to spinal pathology in long-duration astronauts. © 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)
- Jennifer C. Coulombe
- Center for Advanced Orthopedic Studies, Department of Orthopedic SurgeryBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
- Department of Orthopaedic SurgeryHarvard Medical SchoolBostonMassachusettsUSA
| | - Fjola Johannesdottir
- Center for Advanced Orthopedic Studies, Department of Orthopedic SurgeryBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
- Department of Orthopaedic SurgeryHarvard Medical SchoolBostonMassachusettsUSA
| | - Katelyn A. Burkhart
- Center for Advanced Orthopedic Studies, Department of Orthopedic SurgeryBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
| | - Henriette Brummer
- Center for Advanced Orthopedic Studies, Department of Orthopedic SurgeryBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
| | - Brett T. Allaire
- Center for Advanced Orthopedic Studies, Department of Orthopedic SurgeryBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
| | - Mary L. Bouxsein
- Center for Advanced Orthopedic Studies, Department of Orthopedic SurgeryBeth Israel Deaconess Medical CenterBostonMassachusettsUSA
- Department of Orthopaedic SurgeryHarvard Medical SchoolBostonMassachusettsUSA
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Collins L, Boehm E, Luxford C, Clifton‐Bligh R, Grill V. Hypervitaminosis D Secondary to a CYP24A1 Loss-of-Function Mutation: An Unusual Cause of Hypercalcemia in Two Siblings. JBMR Plus 2023; 7:e10788. [PMID: 37701149 PMCID: PMC10494500 DOI: 10.1002/jbm4.10788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/15/2023] [Accepted: 06/06/2023] [Indexed: 09/14/2023] Open
Abstract
Hypervitaminosis D as a cause of hypercalcemia may be due to vitamin D intoxication, granulomatous diseases, or abnormalities of vitamin D metabolism. The CYP24A1 gene encodes for the 24-hydroxylase enzyme, which is responsible for the catabolism of 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D). Mutations in CYP24A1 can result in elevated 1,25(OH)2D causing parathyroid hormone (PTH)-independent hypercalcemia, hypercalciuria, nephrolithiasis, and nephrocalcinosis. We present the cases of two siblings exhibiting hypercalcemia secondary to a CYP24A1 loss-of-function mutation. Case 1 presented initially with PTH-dependent hypercalcemia, with localization of a left upper parathyroid adenoma on parathyroid technetium sestamibi (99mTc-MIBI) uptake study. Despite parathyroidectomy (180 mg adenoma), hypercalcemia, hypercalciuria, and low normal PTH levels persisted. A repeat parathyroid 99mTc-MIBI uptake study localized a second adenoma and a right inferior parathyroidectomy was performed (170 mg adenoma). PTH subsequently became undetectable, however hypercalcemia and hypercalciuria persisted. A new presentation of PTH-independent hypercalcemia found to be secondary to a CYP24A1 loss-of-function mutation in his sibling, Case 2, signaled the underlying cause. Cascade testing confirmed both siblings were homozygous for the pathogenic variant c.1186C>T, p.Arg396Trp (R396W) of CYP24A1 (NM_000782.5). In clinical practice CYP24A1 loss-of-function mutations should be considered in patients presenting with PTH-independent hypercalcemia, hypercalciuria, and 1,25(OH)2D levels in the upper normal or elevated range. Although in our case assays of 24,25(OH)2D were not available, calculation of the 25(OH)D:24,25(OH)2D ratio can assist in the diagnostic process. Possible treatments to manage the risk of hypercalcemia in patients with a CYP24A1 loss-of-function mutation include avoidance of vitamin D oversupplementation and excessive sun exposure. Hydration and bisphosphonate therapy can be useful in managing the hypercalcemia. Although not utilized in our cases, treatment with ketoconazole, fluconazole, and rifampicin have been described as potential therapeutic options. © 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)
- Lucy Collins
- Department of Endocrinology and DiabetesWestern HealthMelbourneVictoriaAustralia
| | - Emma Boehm
- Department of Endocrinology and DiabetesWestern HealthMelbourneVictoriaAustralia
- University of MelbourneMelbourneVictoriaAustralia
| | - Catherine Luxford
- Royal North Shore HospitalKolling InstituteSt LeonardsNew South WalesAustralia
| | - Roderick Clifton‐Bligh
- Royal North Shore HospitalKolling InstituteSt LeonardsNew South WalesAustralia
- Department of EndocrinologyRoyal North Shore HospitalSt LeonardsNew South WalesAustralia
| | - Vivian Grill
- Department of Endocrinology and DiabetesWestern HealthMelbourneVictoriaAustralia
- University of MelbourneMelbourneVictoriaAustralia
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Babey ME, Ewing SK, Strotmeyer ES, Napoli N, Schafer AL, Vittinghoff E, Gundberg CM, Schwartz AV. No Evidence of Association Between Undercarboxylated Osteocalcin and Incident Type 2 Diabetes. J Bone Miner Res 2022; 37:876-884. [PMID: 35118705 PMCID: PMC10441038 DOI: 10.1002/jbmr.4519] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 11/11/2022]
Abstract
Mouse models suggest that undercarboxylated osteocalcin (ucOC), produced by the skeleton, protects against type 2 diabetes development, whereas human studies have been inconclusive. We aimed to determine if ucOC or total OC is associated with incident type 2 diabetes or changes in fasting glucose, insulin resistance (HOMA-IR), or beta-cell function (HOMA-Beta). A subcohort (n = 338; 50% women; 36% black) was identified from participants without diabetes at baseline in the Health, Aging, and Body Composition Study. Cases of incident type 2 diabetes (n = 137) were defined as self-report at an annual follow-up visit, use of diabetes medication, or elevated fasting glucose during 8 years of follow-up. ucOC and total OC were measured in baseline serum. Using a case-cohort design, the association between biomarkers and incident type 2 diabetes was assessed using robust weighted Cox regression. In the subcohort, linear regression models analyzed the associations between biomarkers and changes in fasting glucose, HOMA-IR, and HOMA-Beta over 9 years. Higher levels of ucOC were not statistically associated with increased risk of incident type 2 diabetes (adjusted hazard ratio = 1.06 [95% confidence interval, 0.84-1.34] per 1 standard deviation [SD] increase in ucOC). Results for %ucOC and total OC were similar. Adjusted associations of ucOC, %ucOC, and total OC with changes in fasting glucose, HOMA-IR, and HOMA-Beta were modest and not statistically significant. We did not find evidence of an association of baseline undercarboxylated or total osteocalcin with risk of incident type 2 diabetes or with changes in glucose metabolism in older adults. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Muriel E. Babey
- University of California San Francisco, Division of Endocrinology and Metabolism, San Francisco, CA, USA
| | - Susan K. Ewing
- University of California San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA, USA
| | - Elsa S. Strotmeyer
- Department of Epidemiology, University of Pittsburgh, Center for Aging and Population Health, Pittsburgh, PA, USA
| | - Nicola Napoli
- Universita Campus Bio-Medico di Roma, Division of Endocrinology and Diabetes, Rome, Italy
| | - Anne L. Schafer
- University of California San Francisco, Division of Endocrinology and Metabolism, San Francisco, CA, USA
- University of California San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA, USA
- San Francisco VA Medical Center, Endocrine Research Unit, Medical Service, San Francisco, CA, USA
| | - Eric Vittinghoff
- University of California San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA, USA
| | - Caren M. Gundberg
- Yale University School of Medicine, Department of Orthopedics, New Haven, CT, USA
| | - Ann V. Schwartz
- University of California San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA, USA
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Geels RES, Meier ME, Saikali A, Tsonaka R, Appelman-Dijkstra NM, Boyce AM. Long Bone Fractures in Fibrous Dysplasia/McCune-Albright Syndrome: Prevalence, Natural History, and Risk Factors. J Bone Miner Res 2022; 37:236-243. [PMID: 34668234 PMCID: PMC9548190 DOI: 10.1002/jbmr.4463] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 02/03/2023]
Abstract
Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare bone and endocrine disorder arising along a broad spectrum. Long-bone fractures are a common, painful, and potentially disabling complication. However, fracture prevalence and risk factors have not been well-established, making it difficult to predict which patients are at risk for a severe course. Clinical and imaging data were reviewed from two large, well-phenotyped cohorts (National Institutes of Health [NIH] in the United States and the Leiden University Medical Center [LUMC] in the Netherlands) to identify long-bone fractures at FD sites. Skeletal burden score was quantified using bone scintigraphy. Multiple linear regressions were performed to identify clinical associations with fractures. A total of 419 patients were included (186 NIH, 233 LUMC); 194 (46%) had MAS endocrinopathies. Median age at last follow-up was 30.2 years (range 3.2-84.6, interquartile range [IQR] 25.5), and median skeletal burden score was 16.6 (range 0-75, IQR 33). A total of 48 (59%) patients suffered one or more lifetime fracture (median 1, range 0-70, IQR 4). Median age at first fracture was 8 years (range 1-76, IQR 10). Fracture rates peaked between 6 and 10 years of age and decreased thereafter. Lifetime fracture rate was associated with skeletal burden score (β = 0.40, p < 0.01) and MAS hyperthyroidism (β = 0.22, p = 0.01). Younger age at first fracture was associated with skeletal burden score (β = -0.26, p = 0.01) and male sex (β = -0.23, p = 0.01). Both skeletal burden score >25 and age at first fracture ≤7 years were associated with a higher total number of lifetime fractures (median 4, range 1-70, IQR 5 versus median 1, range 1-13, IQR 1) (p < 0.01). In conclusion, higher skeletal burden score and MAS hyperthyroidism are associated with long-bone fractures in FD/MAS. Both skeletal burden score ≥25 and age at first fracture ≤7 years are associated with a higher lifetime long-bone fracture risk and may predict a more severe clinical course. These results may allow clinicians to identify FD/MAS patients at risk for severe disease who may be candidates for early therapeutic interventions. © 2021 American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Raya E S Geels
- Department of Medicine, Division of Endocrinology, Centre for Bone Quality, Leiden University Medical Centre, Leiden, The Netherlands
| | - Maartje E Meier
- Department of Medicine, Division of Endocrinology, Centre for Bone Quality, Leiden University Medical Centre, Leiden, The Netherlands.,Department of Orthopedic Surgery, Leiden University Medical Centre, Leiden, The Netherlands
| | - Amanda Saikali
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Roula Tsonaka
- Department of Medical Statistics and Bioinformatics, Einthovenweg, Leiden University Medical Center, Leiden, The Netherlands
| | - Natasha M Appelman-Dijkstra
- Department of Medicine, Division of Endocrinology, Centre for Bone Quality, Leiden University Medical Centre, Leiden, The Netherlands
| | - Alison M Boyce
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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Marinelli M, Felici G, Galante F, Gasparini A, Giuliano L, Heinrich S, Pacitti M, Prestopino G, Vanreusel V, Verellen D, Verona C, Rinati GV. Design, realization and characterization of a novel diamond detector prototype for flash radi otherapy dosimetry. Med Phys 2022; 49:1902-1910. [PMID: 35064594 PMCID: PMC9306529 DOI: 10.1002/mp.15473] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 11/28/2022] Open
Abstract
Purpose FLASH radiotherapy (RT) is an emerging technique in which beams with ultra‐high dose rates (UH‐DR) and dose per pulse (UH‐DPP) are used. Commercially available active real‐time dosimeters have been shown to be unsuitable in such conditions, due to severe response nonlinearities. In the present study, a novel diamond‐based Schottky diode detector was specifically designed and realized to match the stringent requirements of FLASH‐RT. Methods A systematic investigation of the main features affecting the diamond response in UH‐DPP conditions was carried out. Several diamond Schottky diode detector prototypes with different layouts were produced at Rome Tor Vergata University in cooperation with PTW‐Freiburg. Such devices were tested under electron UH‐DPP beams. The linearity of the prototypes was investigated up to DPPs of about 26 Gy/pulse and dose rates of approximately 1 kGy/s. In addition, percentage depth dose (PDD) measurements were performed in different irradiation conditions. Radiochromic films were used for reference dosimetry. Results The response linearity of the diamond prototypes was shown to be strongly affected by the size of their active volume as well as by their series resistance. By properly tuning the design layout, the detector response was found to be linear up to at least 20 Gy/pulse, well into the UH‐DPP range conditions. PDD measurements were performed by three different linac applicators, characterized by DPP values at the point of maximum dose of 3.5, 17.2, and 20.6 Gy/pulse, respectively. The very good superimposition of three curves confirmed the diamond response linearity. It is worth mentioning that UH‐DPP irradiation conditions may lead to instantaneous detector currents as high as several mA, thus possibly exceeding the electrometer specifications. This issue was properly addressed in the case of the PTW UNIDOS electrometers. Conclusions The results of the present study clearly demonstrate the feasibility of a diamond detector for FLASH‐RT applications.
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Affiliation(s)
- Marco Marinelli
- Industrial Engineering Dept., University of Rome Tor Vergata, Rome, Italy
| | | | | | - Alessia Gasparini
- Iridium Kankernetwerk, Antwerp, Belgium and University of Antwerp, Antwerp, Belgium
| | - Lucia Giuliano
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Orsay, France
| | - Sophie Heinrich
- Institut Curie, Inserm U 1021-CNRS UMR 3347, University Paris-Saclay, PSL Research University, Orsay, France
| | | | | | - Verdi Vanreusel
- Iridium Kankernetwerk, Antwerp, Belgium and University of Antwerp, Antwerp, Belgium
| | - Dirk Verellen
- Iridium Kankernetwerk, Antwerp, Belgium and University of Antwerp, Antwerp, Belgium
| | - Claudio Verona
- Industrial Engineering Dept., University of Rome Tor Vergata, Rome, Italy
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Gayan‐Ramirez G, Janssens W. Vitamin D Actions: The Lung Is a Major Target for Vitamin D, FGF23, and Klotho. JBMR Plus 2021; 5:e10569. [PMID: 34950829 PMCID: PMC8674778 DOI: 10.1002/jbm4.10569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/29/2021] [Accepted: 10/09/2021] [Indexed: 11/16/2022] Open
Abstract
Vitamin D is well known for its role as a calcium regulator and in maintenance of phosphate homeostasis in musculoskeletal health, and fibroblast growth factor 23 (FGF23) and its coreceptor α-klotho are known for their roles as regulators of serum phosphate levels. However, apart from these classical actions, recent data point out a relevant role of vitamin D and FGF23/klotho in lung health. The expression of the vitamin D receptor by different cell types in the lung and the fact that those cells respond to vitamin D or can locally produce vitamin D indicate that the lung represents a target for vitamin D actions. Similarly, the presence of the four FGF receptor isoforms in the lung and the ability of FGF23 to stimulate pulmonary cells support the concept that the lung is a target for FGF23 actions, whereas the contribution of klotho is still undetermined. This review will give an overview on how vitamin D or FGF23/klotho may act on the lung and interfere positively or negatively with lung health. © 2021 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)
- Ghislaine Gayan‐Ramirez
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department CHROMETAKU LeuvenLeuvenBelgium
| | - Wim Janssens
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department CHROMETAKU LeuvenLeuvenBelgium
- Clinical Department of Respiratory DiseasesUZ LeuvenLeuvenBelgium
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Bohns FR, Shih Y, Chuang Y, Akhtar R, Chen P. Influence of Prednisolone and Alendronate on the de novo Mineralization of Zebrafish Caudal Fin. JBMR Plus 2021; 5:e10435. [PMID: 33615104 PMCID: PMC7872341 DOI: 10.1002/jbm4.10435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/22/2020] [Accepted: 11/05/2020] [Indexed: 12/11/2022] Open
Abstract
Dysregulated balance between bone resorption and formation mediates the onset and progression of osteoporosis. The administration of prednisolone is known to induce osteoporosis, whereas alendronate is commonly used to reverse the process. However, the assessment of the effects of such medicines on the nanostructure of bone remodeling and mechanical properties remains a major technical challenge. The aim of this study was to apply various analytical approaches to evaluate the compositional, morphological, and mechanical properties of regenerative zebrafish caudal fin bony rays affected by prednisolone and alendronate. Adult wild-type AB strain zebrafish were first exposed to 125μM of prednisolone for 14 days to develop glucocorticoid-induced osteoporosis. Fish fins were then amputated and let to regenerate for 21 days in tank water containing 30μM of alendronate or no alendronate. The lepidotrichia in the proximal and distal regions were evaluated separately using confocal microscope, scanning electron microscope, electron-dispersive spectroscopy, Raman spectroscopy, atomic force microscopy, and a triboindenter. As expected, prednisolone led to significant osteoporotic phenotypes. A decrease of Ca/P ratio was observed in the osteoporotic subjects (1.46 ± 0.04) as compared to the controls (1.74 ± 0.10). Subsequent treatment of alendronate overmineralized the bony rays during regeneration. Enhanced phosphate deposition was detected in the proximal part with alendronate treatment. Moreover, prednisolone attenuated the reduced elastic modulus and hardness levels (5.60 ± 5.04 GPa and 0.12 ± 0.17 GPa, respectively), whereas alendronate recovered them to the pre-amputation condition (8.68 ± 8.74 GPa and 0.34 ± 0.47 GPa, respectively). As an emerging model of osteoporosis, regrowth of zebrafish caudal fin was shown to be a reliable assay system to investigate the various effects of medicines in the de novo mineralization process. © 2020 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)
- Fabio Rocha Bohns
- Department of Materials Science and EngineeringNational Tsing Hua UniversityHsinchuTaiwan
- Department of Mechanical, Materials and Aerospace EngineeringUniversity of LiverpoolLiverpoolUK
- International Intercollegiate Ph.D. ProgramNational Tsing Hua University 101HsinchuTaiwan
| | - Yann‐Rong Shih
- Department of Materials Science and EngineeringNational Tsing Hua UniversityHsinchuTaiwan
| | - Yung‐Jen Chuang
- Department of Medical Science and Institute of Bioinformatics and Structural BiologyNational Tsing Hua UniversityHsinchuTaiwan
| | - Riaz Akhtar
- Department of Mechanical, Materials and Aerospace EngineeringUniversity of LiverpoolLiverpoolUK
| | - Po‐Yu Chen
- Department of Materials Science and EngineeringNational Tsing Hua UniversityHsinchuTaiwan
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Devaraja J, Jacques R, Paggiosi M, Clark C, Dimitri P. Impact of Type 1 Diabetes Mellitus on Skeletal Integrity and Strength in Adolescents as Assessed by HRpQCT. JBMR Plus 2020; 4:e10422. [PMID: 33210068 PMCID: PMC7657396 DOI: 10.1002/jbm4.10422] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 09/05/2020] [Accepted: 09/26/2020] [Indexed: 12/16/2022] Open
Abstract
Adults with type 1 diabetes mellitus (T1DM) are at risk of premature osteoporosis and fractures. The onset of T1DM typically starts during childhood and adolescence. Thus, the effects of DM on the skeleton may be established during this period. Studies in children with T1DM primarily use DXA with conflicting results. We present the first study in adolescents assessing the impact of T1DM on skeletal microstructure and strength using HRpQCT. We recruited 22 patients aged 12 to 16 years with T1DM who were matched by age, gender, and pubertal stage with healthy controls. Paired t tests were applied to assess differences in cortical and trabecular microarchitecture measurements from HRpQCT, and skeletal strength from HRpQCT-derived microfinite element analysis. Subtotal body, lumbar, and pelvic parameters were assessed using DXA. There was no significant difference in subtotal body, lumbar spine, and pelvic BMD between T1DM and control pairs. However, tibial trabecular thickness was lower (-0.005 mm; 95% CI, -0.01 to -0.001; p = 0.029) and trabecular loading was lower at the distal radius (ratio of the load taken by the trabecular bone in relation to the total load at the distal end (Tb.F/TF) distal: -6.2; 95% CI, -12.4 to -0.03; p = 0.049), and distal and proximal tibia (Tb.F/TF distal: -5.2, 95% CI, -9.2 to -1.2; p = 0.013; and Tb.F/TF proximal: -5.0, 95% CI, -9.8 to -0.1; p = 0.047) in T1DM patients. A subanalysis of radial data of participants with duration of T1DM of at least 2 years and their matched controls demonstrated a reduced trabecular bone number (-0.15, 95% CI, -0.26 to -0.04; p = 0.012), increased trabecular separation (0.041 mm, 95% CI, 0.009-0.072; p = 0.015), an increased trabecular inhomogeneity (0.018, 95% CI, 0.003-0.034; p = 0.021). Regression models demonstrated a reduction in tibial stiffness (-0.877 kN/mm; p = 0.03) and tibial failure load (-0.044 kN; p = 0.03) with higher HbA1C. Thus, in adolescents with T1DM, detrimental changes are seen in tibial and radial microarchitecture and tibial and radial strength before changes in DXA occur and may result from poor diabetic control. © 2020 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)
- Janani Devaraja
- Department of Paediatric Endocrinology Sheffield Children's NHS Foundation Trust Sheffield UK
| | - Richard Jacques
- The School of Health and Related Research, University of Sheffield Sheffield UK
| | - Margaret Paggiosi
- Mellanby Centre for Bone Research University of Sheffield Sheffield UK
| | - Carolyn Clark
- Directorate of Research & Innovation, Sheffield Children's NHS Foundation Trust Sheffield UK
| | - Paul Dimitri
- Department of Paediatric Endocrinology Sheffield Children's NHS Foundation Trust Sheffield UK.,Mellanby Centre for Bone Research University of Sheffield Sheffield UK.,Sheffield Children's NHS Foundation Trust Sheffield UK
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Schutten MM, Knoblaugh S, Salas E, Edmondson E, Bienzle D, Cossic B, Everitt J, Saravanan C, Schmidt S, Schumacher V, Zimmerman K. Letter to the Editor Regarding "Pathology Informatics Education Committee of the American College of Veterinary Pathologists (ACVP)". Toxicol Pathol 2020; 49:709-710. [PMID: 33043872 DOI: 10.1177/0192623320962427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Melissa M Schutten
- Department of Safety Assessment, Genentech, South San Francisco, CA, USA
| | - Sue Knoblaugh
- Department of Veterinary Biosciences, 2647The Ohio State University, Columbus, OH, USA
| | - Elisa Salas
- 17681IDEXX Laboratories, Inc., Westbrook, ME, USA
| | - Elijah Edmondson
- Molecular Histopathology Lab, 437329Frederick National Lab for Cancer Research, Frederick, MD, USA
| | - Dorothee Bienzle
- Department of Pathobiology, Ontario Veterinary College, 3653University of Guelph, Guelph, Ontario, Canada
| | | | - Jeffrey Everitt
- Department of Pathology, 3065Duke University Medical Center, Durham, NC, USA
| | - Chandrassegar Saravanan
- Translational Medicine: Preclinical Safety, Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Sarah Schmidt
- 17681IDEXX Laboratories, Inc., North Grafton, MA, USA
| | - Vanessa Schumacher
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Basel, Switzerland
| | - Kurt Zimmerman
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech University, VA, USA
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Loftus A, Cappariello A, George C, Ucci A, Shefferd K, Green A, Paone R, Ponzetti M, Delle Monache S, Muraca M, Teti A, Rucci N. Extracellular Vesicles From Osteotropic Breast Cancer Cells Affect Bone Resident Cells. J Bone Miner Res 2020; 35:396-412. [PMID: 31610048 DOI: 10.1002/jbmr.3891] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 10/04/2019] [Accepted: 10/06/2019] [Indexed: 12/12/2022]
Abstract
Extracellular vesicles (EVs) are emerging as mediators of a range of pathological processes, including cancer. However, their role in bone metastases has been poorly explored. We investigated EV-mediated effects of osteotropic breast cancer cells (MDA-MB-231) on bone resident cells and endothelial cells. Pretreatment of osteoblasts with conditioned medium (CM) of MDA-MB-231 (MDA) cells promoted pro-osteoclastogenic and pro-angiogenic effects by osteoblast EVs (OB-EVs), as well as an increase of RANKL-positive OB-EVs. Moreover, when treating osteoblasts with MDA-EVs, we observed a reduction of their number, metabolic activity, and alkaline phosphatase (Alp) activity. MDA-EVs also reduced transcription of Cyclin D1 and of the osteoblast-differentiating genes, while enhancing the expression of the pro-osteoclastogenic factors Rankl, Lcn2, Il1b, and Il6. Interestingly, a cytokine array on CM from osteoblasts treated with MDA-EVs showed an increase of the cytokines CCL3, CXCL2, Reg3G, and VEGF, while OPG and WISP1 were downregulated. MDA-EVs contained mRNAs of genes involved in bone metabolism, as well as cytokines, including PDGF-BB, CCL3, CCL27, VEGF, and Angiopoietin 2. In line with this profile, MDA-EVs increased osteoclastogenesis and in vivo angiogenesis. Finally, intraperitoneal injection of MDA-EVs in mice revealed their ability to reach the bone microenvironment and be integrated by osteoblasts and osteoclasts. In conclusion, we showed a role for osteoblast-derived EVs and tumor cell-derived EVs in the deregulation of bone and endothelial cell physiology, thus fueling the vicious cycle induced by bone tumors. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Alexander Loftus
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Alfredo Cappariello
- Oncohematology Department, IRCCS Bambino Gesù Children's Hospital Research Laboratories, Rome, Italy
| | - Christopher George
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Argia Ucci
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Kirsty Shefferd
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Alice Green
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Riccardo Paone
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Marco Ponzetti
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Simona Delle Monache
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Maurizio Muraca
- Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Anna Teti
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Nadia Rucci
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
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11
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Folkert IW, Devalaraja S, Linette GP, Weber K, Haldar M. Primary Bone Tumors: Challenges and Opportunities for CAR-T Therapies. J Bone Miner Res 2019; 34:1780-1788. [PMID: 31441962 DOI: 10.1002/jbmr.3852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/10/2019] [Accepted: 07/27/2019] [Indexed: 12/22/2022]
Abstract
Primary malignant bone tumors are rare, occur in all age groups, and include distinct entities such as osteosarcoma, Ewing sarcoma, and chondrosarcoma. Traditional treatment with some combination of chemotherapy, surgery, and radiation has reached the limit of efficacy, with substantial room for improvement in patient outcome. Furthermore, genomic characterization of these tumors reveals a paucity of actionable molecular targets. Against this backdrop, recent advances in cancer immunotherapy represent a silver lining in the treatment of primary bone cancer. Major strategies in cancer immunotherapy include stimulating naturally occurring anti-tumor T cells and adoptive transfer of tumor-specific cytotoxic T cells. Chimeric antigen receptor T cells (CAR-T cells) belong to the latter strategy and are an impressive application of both insights into T cell biology and advances in genetic engineering. In this review, we briefly describe the CAR-T approach and discuss its applications in primary bone tumors. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Ian W Folkert
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samir Devalaraja
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gerald P Linette
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kristy Weber
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Penn Sarcoma Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Malay Haldar
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Penn Sarcoma Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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12
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Hughes P, Hassan I, Que L, Mead P, Lee JH, Love DR, Prosser DO, Cundy T. Observations on the Natural History of Camurati-Engelmann Disease. J Bone Miner Res 2019; 34:875-882. [PMID: 30690794 DOI: 10.1002/jbmr.3670] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/05/2018] [Indexed: 11/07/2022]
Abstract
Camurati-Engelmann disease (OMIM 31300) is a rare cranio-tubular bone dysplasia characterized by osteosclerosis of the long bones and skull caused by dominantly-inherited mutations in the transforming growth factor beta 1 (TGFB1) gene. A wide variation in phenotype has been recognized, even within families carrying the same mutation. In addition, aspects of the natural history of the disorder, in particular whether it is always progressive or can remit spontaneously, remain uncertain. In a large kindred carrying a TGFB1 gene mutation (c.653G > A; p.R218H) we have attempted to clarify the extent of phenotypic variability and the natural history of the disease through detailed individual histories of symptoms, and skeletal imaging by both radiography and scintigraphy. Only one subject had the classical childhood onset with bone pain in the legs and gait disturbance. Eight subjects reported the onset of leg pain in their teenage years that, by their early 20s, had either resolved or persisted at a low level. Two of these eight later developed cranial nerve palsies. There was a wide variation in the radiographic appearance in adults, but disease extent and activity in long bones, as assessed by scintigraphy, was inversely correlated with age (p < 0.025). In younger subjects the radiographic and scintigraphic appearances were concordant, but in older subjects the scintigram could be quiescent despite florid radiographic changes. Sequential scintigrams in two subjects showed reduced activity in the later scan. One subject had suffered meningoencephalitis in early childhood that resulted in paresis of one arm. The affected arm showed markedly less disease involvement, implicating mechanical or growth factors in its etiology. Our data suggest that the natural history of Camurati-Engelmann disease can be benign, and that disease activity commonly attenuates in adulthood. Severe cases of childhood onset and/or with cranial nerve involvement, may occur only in a minority of mutation carriers. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Peter Hughes
- Radiology, Auckland City Hospital, Auckland, New Zealand
| | - Ibrahim Hassan
- Nuclear Medicine, Auckland City Hospital, Auckland, New Zealand
| | - Lorna Que
- Nuclear Medicine, Auckland City Hospital, Auckland, New Zealand
| | - Patricia Mead
- Nuclear Medicine, Auckland City Hospital, Auckland, New Zealand
| | | | - Donald R Love
- Diagnostic Genetics, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Debra O Prosser
- Diagnostic Genetics, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Tim Cundy
- Endocrinology, Auckland City Hospital, Auckland, New Zealand
- Department of Medicine, Faculty of Medical & Health Sciences, University of Auckland, Auckland, New Zealand
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13
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Gorvin CM, Ahmad BN, Stechman MJ, Loh NY, Hough TA, Leo P, Marshall M, Sethi S, Bentley L, Piret SE, Reed A, Jeyabalan J, Christie PT, Wells S, Simon MM, Mallon AM, Schulz H, Huebner N, Brown MA, Cox RD, Brown SD, Thakker RV. An N-Ethyl-N-Nitrosourea (ENU)-Induced Tyr265Stop Mutation of the DNA Polymerase Accessory Subunit Gamma 2 (Polg2) Is Associated With Renal Calcification in Mice. J Bone Miner Res 2019; 34:497-507. [PMID: 30395686 PMCID: PMC6446808 DOI: 10.1002/jbmr.3624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 10/12/2018] [Accepted: 10/28/2018] [Indexed: 12/24/2022]
Abstract
Renal calcification (RCALC) resulting in nephrolithiasis and nephrocalcinosis, which affects ∼10% of adults by 70 years of age, involves environmental and genetic etiologies. Thus, nephrolithiasis and nephrocalcinosis occurs as an inherited disorder in ∼65% of patients, and may be associated with endocrine and metabolic disorders including: primary hyperparathyroidism, hypercalciuria, renal tubular acidosis, cystinuria, and hyperoxaluria. Investigations of families with nephrolithiasis and nephrocalcinosis have identified some causative genes, but further progress is limited as large families are unavailable for genetic studies. We therefore embarked on establishing mouse models for hereditary nephrolithiasis and nephrocalcinosis by performing abdominal X-rays to identify renal opacities in N-ethyl-N-nitrosourea (ENU)-mutagenized mice. This identified a mouse with RCALC inherited as an autosomal dominant trait, designated RCALC type 2 (RCALC2). Genomewide mapping located the Rcalc2 locus to a ∼16-Mbp region on chromosome 11D-E2 and whole-exome sequence analysis identified a heterozygous mutation in the DNA polymerase gamma-2, accessory subunit (Polg2) resulting in a nonsense mutation, Tyr265Stop (Y265X), which co-segregated with RCALC2. Kidneys of mutant mice (Polg2+/Y265X ) had lower POLG2 mRNA and protein expression, compared to wild-type littermates (Polg2+/+ ). The Polg2+/Y265X and Polg2+/+ mice had similar plasma concentrations of sodium, potassium, calcium, phosphate, chloride, urea, creatinine, glucose, and alkaline phosphatase activity; and similar urinary fractional excretion of calcium, phosphate, oxalate, and protein. Polg2 encodes the minor subunit of the mitochondrial DNA (mtDNA) polymerase and the mtDNA content in Polg2+/Y265X kidneys was reduced compared to Polg2+/+ mice, and cDNA expression profiling revealed differential expression of 26 genes involved in several biological processes including mitochondrial DNA function, apoptosis, and ubiquitination, the complement pathway, and inflammatory pathways. In addition, plasma of Polg2+/Y265X mice, compared to Polg2+/+ littermates had higher levels of reactive oxygen species. Thus, our studies have identified a mutant mouse model for inherited renal calcification associated with a Polg2 nonsense mutation. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Bushra N Ahmad
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Michael J Stechman
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Nellie Y Loh
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Tertius A Hough
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Paul Leo
- Translational Genomics Group, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology at Translational Research Institute, Brisbane, Australia
| | - Mhairi Marshall
- Translational Genomics Group, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology at Translational Research Institute, Brisbane, Australia
| | - Siddharth Sethi
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Liz Bentley
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Sian E Piret
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Anita Reed
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jeshmi Jeyabalan
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Paul T Christie
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Sara Wells
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Michelle M Simon
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Ann-Marie Mallon
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Herbert Schulz
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | | | - Matthew A Brown
- Translational Genomics Group, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology at Translational Research Institute, Brisbane, Australia
| | - Roger D Cox
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Steve D Brown
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council, Harwell, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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14
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Dirkes RK, Ortinau LC, Rector RS, Olver TD, Hinton PS. Insulin-Stimulated Bone Blood Flow and Bone Biomechanical Properties Are Compromised in Obese, Type 2 Diabetic OLETF Rats. JBMR Plus 2017; 1:116-126. [PMID: 30283885 PMCID: PMC6124191 DOI: 10.1002/jbm4.10007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 01/20/2023] Open
Abstract
Type 2 diabetes (T2D) increases skeletal fragility and fracture risk; however, the underlying mechanisms remain to be identified. Impaired bone vascular function, in particular insulin‐stimulated vasodilation and blood flow is a potential, yet unexplored mechanism. The purpose of this study was to determine the effects of T2D on femoral biomechanical properties, trabecular microarchitecture, and insulin‐stimulated bone vasodilation by comparison of hyperphagic Otsuka Long‐Evans Tokushima Fatty (OLETF) rats with normoglycemic control OLETF rats. Four‐week old, male OLETF rats were randomized to two groups: type 2 diabetes (O‐T2D) or normoglycemic control (O‐CON). O‐T2D were allowed ad libitum access to a rodent chow diet and O‐CON underwent moderate caloric restriction (30% restriction relative to intake of O‐T2D) to maintain normal body weight (BW) and glycemia until 40 weeks of age. Hyperphagic O‐T2D rats had significantly greater BW, body fat, and blood glucose than O‐CON. Total cross‐sectional area (Tt.Ar), cortical area (Ct.Ar), Ct.Ar/Tt.Ar, and polar moment of inertia of the mid‐diaphyseal femur adjusted for BW were greater in O‐T2D rats versus O‐CON. Whole‐bone biomechanical properties of the femur assessed by torsional loading to failure did not differ between O‐T2D and O‐CON, but tissue‐level strength and stiffness adjusted for BW were reduced in O‐T2D relative to O‐CON. Micro–computed tomography (μCT) of the distal epiphysis showed that O‐T2D rats had reduced percent bone volume, trabecular number, and connectivity density, and greater trabecular spacing compared with O‐CON. Basal tibial blood flow assessed by microsphere infusion was similar in O‐T2D and O‐CON, but the blood flow response to insulin stimulation in both the proximal epiphysis and diaphyseal marrow was lesser in O‐T2D compared to O‐CON. In summary, impaired insulin‐stimulated bone blood flow is associated with deleterious changes in bone trabecular microarchitecture and cortical biomechanical properties in T2D, suggesting that vascular dysfunction might play a causal role in diabetic bone fragility. © 2017 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Affiliation(s)
- Rebecca K Dirkes
- Department of Nutrition and Exercise Physiology University of Missouri-Columbia Columbia MO USA
| | - Laura C Ortinau
- Department of Nutrition and Exercise Physiology University of Missouri-Columbia Columbia MO USA
| | - R Scott Rector
- Department of Nutrition and Exercise Physiology University of Missouri-Columbia Columbia MO USA.,Division of Gastroenterology and Hepatology Department of Medicine University of Missouri-Columbia Columbia MO USA.,Research Service Harry S Truman Memorial VA Hospital Columbia MO USA
| | - T Dylan Olver
- Department of Biomedical Sciences University of Missouri-Columbia Columbia MO USA
| | - Pamela S Hinton
- Department of Nutrition and Exercise Physiology University of Missouri-Columbia Columbia MO USA
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