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Poudel SB, Ruff RR, Yildirim G, Miller RA, Harrison DE, Strong R, Kirsch T, Yakar S. Development of primary osteoarthritis during aging in genetically diverse UM-HET3 mice. Arthritis Res Ther 2024; 26:118. [PMID: 38851726 PMCID: PMC11161968 DOI: 10.1186/s13075-024-03349-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 05/27/2024] [Indexed: 06/10/2024] Open
Abstract
BACKGROUND Primary osteoarthritis (OA) occurs without identifiable underlying causes such as previous injuries or specific medical conditions. Age is a major contributing factor to OA, and as one ages, various joint tissues undergo gradual change, including degeneration of the articular cartilage, alterations in subchondral bone (SCB) morphology, and inflammation of the synovium. METHODS We investigated the prevalence of primary OA in aged, genetically diverse UM-HET3 mice. Articular cartilage (AC) integrity and SCB morphology were assessed in 182 knee joints of 22-25 months old mice using the Osteoarthritis Research Society International (OARSI) scoring system and micro-CT, respectively. Additionally, we explored the effects of methylene blue (MB) and mitoquinone (MitoQ), two agents that affect mitochondrial function, on the prevalence and progression of OA during aging. RESULTS Aged UM-HET3 mice showed a high prevalence of primary OA in both sexes. Significant positive correlations were found between cumulative AC (cAC) scores and synovitis in both sexes, and osteophyte formation in female mice. Ectopic chondrogenesis did not show significant correlations with cAC scores. Significant direct correlations were found between AC scores and inflammatory markers in chondrocytes, including matrix metalloproteinase-13, inducible nitric oxide synthase, and the NLR family pyrin domain containing-3 inflammasome in both sexes, indicating a link between OA severity and inflammation. Additionally, markers of cell cycle arrest, such as p16 and β-galactosidase, also correlated with AC scores. In male mice, no significant correlations were found between SCB morphology traits and cAC scores, while in female mice, significant correlations were found between cAC scores and tibial SCB plate bone mineral density. Notably, MB and MitoQ treatments influenced the disease's progression in a sex-specific manner. MB treatment significantly reduced cAC scores at the medial knee joint, while MitoQ treatment reduced cAC scores, but these did not reach significance. CONCLUSIONS Our study provides comprehensive insights into the prevalence and progression of primary OA in aged UM-HET3 mice, highlighting the sex-specific effects of MB and MitoQ treatments. The correlations between AC scores and various pathological factors underscore the multifaceted nature of OA and its association with inflammation and subchondral bone changes.
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Affiliation(s)
- Sher Bahadur Poudel
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24th Street, New York, NY, 10010-4086, USA
| | - Ryan R Ruff
- David B. Kriser Dental Center, Biostatistics Core, Department of Epidemiology and Health Promotion, New York University College of Dentistry, New York, NY, 10010-4086, USA
| | - Gozde Yildirim
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24th Street, New York, NY, 10010-4086, USA
| | - Richard A Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI, 48105, USA
| | | | - Randy Strong
- Geriatric Research, Education and Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, TX, 78229, USA
- Barshop Institute for Longevity and Aging Studies and Department of Pharmacology, The University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Thorsten Kirsch
- Department of Orthopaedic Surgery, NYU Grossman School of Medicine, New York, NY, 10100, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, New York, NY, 10010, USA
| | - Shoshana Yakar
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24th Street, New York, NY, 10010-4086, USA.
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Poudel SB, Ruff RR, Yildirim G, Miller RA, Harrison DE, Strong R, Kirsch T, Yakar S. Development of primary osteoarthritis during aging in genetically diverse UM-HET3 mice. RESEARCH SQUARE 2024:rs.3.rs-3858256. [PMID: 38343826 PMCID: PMC10854287 DOI: 10.21203/rs.3.rs-3858256/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Background Primary osteoarthritis (OA) occurs without identifiable underlying causes such as previous injuries or specific medical conditions. Age is a major contributing factor to OA, and as one ages, various joint tissues undergo gradual change, including degeneration of the articular cartilage, alterations in subchondral bone (SCB) morphology, and inflammation of the synovium. Methods We investigated the prevalence of primary OA in aged, genetically diverse UM-HET3 mice. Articular cartilage (AC) integrity and SCB morphology were assessed in 182 knee joints of 22-25 months old mice using the Osteoarthritis Research Society International (OARSI) scoring system and micro-CT, respectively. Additionally, we explored the effects of methylene blue (MB) and mitoquinone (MitoQ), two agents that affect mitochondrial function, on the prevalence and progression of OA during aging. Results Aged UM-HET3 mice showed a high prevalence of primary OA in both sexes. Significant positive correlations were found between cumulative AC (cAC) scores and synovitis in both sexes, and osteophyte formation in female mice. Ectopic chondrogenesis did not show significant correlations with cAC scores. Significant direct correlations were found between AC scores and inflammatory markers in chondrocytes, including matrix metalloproteinase-13, inducible nitric oxide synthase, and the NLR family pyrin domain containing-3 inflammasome in both sexes, indicating a link between OA severity and inflammation. Additionally, markers of cell cycle arrest, such as p16 and β-galactosidase, also correlated with AC scores. In male mice, no significant correlations were found between SCB morphology traits and cAC scores, while in female mice, significant correlations were found between cAC scores and tibial SCB plate bone mineral density. Notably, MB and MitoQ treatments influenced the disease's progression in a sex-specific manner. MB treatment significantly reduced cAC scores at the medial knee joint, while MitoQ treatment reduced cAC scores, but these did not reach significance. Conclusions Our study provides comprehensive insights into the prevalence and progression of primary OA in aged UM-HET3 mice, highlighting the sex-specific effects of MB and MitoQ treatments. The correlations between AC scores and various pathological factors underscore the multifaceted nature of OA and its association with inflammation and subchondral bone changes.
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Affiliation(s)
- Sher Bahadur Poudel
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY
| | - Ryan R Ruff
- David B. Kriser Dental Center, Biostatistics Core, Department of Epidemiology and Health Promotion, New York University College of Dentistry New York, NY 10010-4086
| | - Gozde Yildirim
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY
| | - Richard A Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI, USA
| | | | - Randy Strong
- Geriatric Research, Education and Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, TX, USA; Barshop Institute for Longevity and Aging Studies and Department of Pharmacology, The University of Texas Health Science Center, San Antonio, TX, USA
| | - Thorsten Kirsch
- Department of Orthopaedic Surgery, NYU Grossman School of Medicine, and Department of Biomedical Engineering, NYU Tandon School of Engineering, New York, NY
| | - Shoshana Yakar
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY
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Poudel SB, Ruff RR, Yildirim G, Miller RA, Harrison DE, Strong R, Kirsch T, Yakar S. Development of primary osteoarthritis during aging in genetically diverse UM-HET3 mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.16.571693. [PMID: 38168298 PMCID: PMC10760163 DOI: 10.1101/2023.12.16.571693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
This study investigated the prevalence and progression of primary osteoarthritis (OA) in aged UM-HET3 mice. Using the Osteoarthritis Research Society International (OARSI) scoring system, we assessed articular cartilage (AC) integrity in 182 knee joints of 22-25 months old mice. Aged UM-HET3 mice showed a high prevalence of primary OA in both sexes. Significant positive correlations were found between cumulative AC (cAC) scores and synovitis in both sexes, and osteophyte formation in female mice. Ectopic chondrogenesis did not show significant correlations with cAC scores. Significant direct correlations were found between AC scores and inflammatory markers in chondrocytes, including matrix metalloproteinase-13 (MMP-13), inducible nitric oxide synthase (iNOS), and the NLR family pyrin domain containing-3 (NLRP3) inflammasome in both sexes, indicating a link between OA severity and inflammation. Additionally, markers of cell cycle arrest, such as p16 and β-galactosidase, also correlated with AC scores. Using micro-CT, we examined the correlations between subchondral bone (SCB) morphology traits and AC scores. In male mice, no significant correlations were found between SCB morphology traits and cAC scores, while in female mice, significant correlations were found between cAC scores and tibial SCB plate bone mineral density. Finally, we explored the effects of methylene blue (MB) and mitoquinone (MitoQ), two agents that affect mitochondrial function, on the prevalence and progression of OA during aging. Notably, MB and MitoQ treatments influenced the disease's progression in a sex-specific manner. MB treatment significantly reduced cAC scores at the medial knee joint, while MitoQ treatment reduced cAC scores, but these did not reach significance. In conclusion, our study provides comprehensive insights into the prevalence and progression of primary OA in aged UM-HET3 mice, highlighting the sex-specific effects of MB and MitoQ treatments. The correlations between AC scores and various pathological factors underscore the multifaceted nature of OA and its association with inflammation and subchondral bone changes.
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Yildirim G, Bergamo ETP, Poudel SB, Ruff RR, Dixit M, Hu B, Mijares DQ, Witek L, Chlebek C, Harrison DE, Strong R, Miller RA, Ladiges W, Bromage TG, Rosen CJ, Yakar S. Long-term effects of canagliflozin treatment on the skeleton of aged UM-HET3 mice. GeroScience 2023; 45:1933-1951. [PMID: 37166526 PMCID: PMC10400751 DOI: 10.1007/s11357-023-00803-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/18/2023] [Indexed: 05/12/2023] Open
Abstract
Sodium glucose cotransporter-2 inhibitors (SGLT2is) promote urinary glucose excretion and decrease plasma glucose levels independent of insulin. Canagliflozin (CANA) is an SGLT2i, which is widely prescribed, to reduce cardiovascular complications, and as a second-line therapy after metformin in the treatment of type 2 diabetes mellitus. Despite the robust metabolic benefits, reductions in bone mineral density (BMD) and cortical fractures were reported for CANA-treated subjects. In collaboration with the National Institute on Aging (NIA)-sponsored Interventions Testing Program (ITP), we tested skeletal integrity of UM-HET3 mice fed control (137 mice) or CANA-containing diet (180 ppm, 156 mice) from 7 to 22 months of age. Micro-computed tomography (micro-CT) revealed that CANA treatment caused significant thinning of the femur mid-diaphyseal cortex in both male and female mice, did not affect trabecular bone architecture in the distal femur or the lumbar vertebra-5 in male mice, but was associated with thinning of the trabeculae at the distal femur in CANA-treated female mice. In male mice, CANA treatment is associated with significant reductions in cortical bone volumetric BMD by micro-CT, and by quantitative backscattered scanning electron microscopy. Raman microspectroscopy, taken at the femur mid-diaphyseal posterior cortex, showed significant reductions in the mineral/matrix ratio and an increased carbonate/phosphate ratio in CANA-treated male mice. These data were supported by thermogravimetric assay (TGA) showing significantly decreased mineral and increased carbonate content in CANA-treated male mice. Finally, the sintered remains of TGA were subjected to X-ray diffraction and showed significantly higher fraction of whitlockite, a calcium orthophosphate mineral, which has higher resorbability than hydroxyapatite. Overall, long-term CANA treatment compromised bone morphology and mineral composition of bones, which likely contribute to increased fracture risk seen with this drug.
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Affiliation(s)
- Gozde Yildirim
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Edmara T. P. Bergamo
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
| | - Sher Bahadur Poudel
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Ryan R. Ruff
- David B. Kriser Dental Center, Department of Epidemiology and Health Promotion, New York University College of Dentistry, New York, NY 10010-4086 USA
| | - Manisha Dixit
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Bin Hu
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Dindo Q. Mijares
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
| | - Lukasz Witek
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
- Department of Biomedical Engineering, Tandon School of Engineering New York University, Brooklyn, NY 11201 USA
| | - Carolyn Chlebek
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, USA
| | | | - Randy Strong
- Geriatric Research, Education and Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, TX USA
- Barshop Institute for Longevity and Aging Studies and Department of Pharmacology, The University of Texas Health Science Center, San Antonio, TX USA
| | - Richard A. Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI USA
| | - Warren Ladiges
- Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, WA USA
| | - Timothy G. Bromage
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Clifford J. Rosen
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, USA
| | - Shoshana Yakar
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
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Lu L, Huang J, Xu F, Xiao Z, Wang J, Zhang B, David NV, Arends D, Gu W, Ackert-Bicknell C, Sabik OL, Farber CR, Quarles LD, Williams RW. Genetic Dissection of Femoral and Tibial Microarchitecture. JBMR Plus 2019; 3:e10241. [PMID: 31844829 PMCID: PMC6894729 DOI: 10.1002/jbm4.10241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 09/09/2019] [Accepted: 09/16/2019] [Indexed: 12/29/2022] Open
Abstract
Our understanding of the genetic control of bone strength has relied mainly on estimates of bone mineral density. Here we have mapped genetic factors that influence femoral and tibial microarchitecture using high‐resolution x‐ray computed tomography (8‐μm isotropic voxels) across a family of 61 BXD strains of mice, roughly 10 isogenic cases per strain and balanced by sex. We computed heritabilities for 25 cortical and trabecular traits. Males and females have well‐matched heritabilities, ranging from 0.25 to 0.75. We mapped 16 genetic loci most of which were detected only in females. There is also a bias in favor of loci that control cortical rather than trabecular bone. To evaluate candidate genes, we combined well‐established gene ontologies with bone transcriptome data to compute bone‐enrichment scores for all protein‐coding genes. We aligned candidates with those of human genome‐wide association studies. A subset of 50 strong candidates fell into three categories: (1) experimentally validated genes already known to modulate bone function (Adamts4, Ddr2, Darc, Adam12, Fkbp10, E2f6, Adam17, Grem2, Ifi204); (2) candidates without any experimentally validated function in bone (eg, Greb1, Ifi202b), but linked to skeletal phenotypes in human cohorts; and (3) candidates that have high bone‐enrichment scores, but for which there is not yet any functional link to bone biology or skeletal system disease (including Ifi202b, Ly9, Ifi205, Mgmt, F2rl1, Iqgap2). Our results highlight contrasting genetic architecture between sexes and among major bone compartments. The alignment of murine and human data facilitates function analysis and should prove of value for preclinical testing of molecular control of bone structure. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Lu Lu
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
| | - Jinsong Huang
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
| | - Fuyi Xu
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
| | - Zhousheng Xiao
- Department of Medicine University of Tennessee Health Science Center Memphis TN USA
| | - Jing Wang
- Department of Molecular and Human Genetics Baylor College of Medicine Houston TX USA
| | - Bing Zhang
- Department of Molecular and Human Genetics Baylor College of Medicine Houston TX USA
| | - Nicolae Valentin David
- Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Danny Arends
- Breeding Biology and Molecular Animal Breeding Humboldt University Berlin Germany
| | - Weikuan Gu
- Department of Orthopaedic Surgery and Biomedical Engineering University of Tennessee Health Science Center Memphis TN USA
| | | | - Olivia L Sabik
- Center for Public Health Genomics University of Virginia Charlottesville VA USA
| | - Charles R Farber
- Center for Public Health Genomics University of Virginia Charlottesville VA USA
| | - Leigh Darryl Quarles
- Department of Medicine University of Tennessee Health Science Center Memphis TN USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics University of Tennessee Health Science Center Memphis TN USA
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Mazza B. Postcranial morphological variation between hunter‐gatherers and horticulturalists from the lower Paraná River Delta, Argentina. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 170:176-195. [DOI: 10.1002/ajpa.23889] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/08/2019] [Accepted: 06/17/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Bárbara Mazza
- Instituto Nacional de Antropología y Pensamiento Latinoamericano, CONICET Buenos Aires Argentina
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Reyes Fernandez PC, Replogle RA, Wang L, Zhang M, Fleet JC. Novel Genetic Loci Control Calcium Absorption and Femur Bone Mass as Well as Their Response to Low Calcium Intake in Male BXD Recombinant Inbred Mice. J Bone Miner Res 2016; 31:994-1002. [PMID: 26636428 PMCID: PMC4862900 DOI: 10.1002/jbmr.2760] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/24/2015] [Accepted: 12/02/2015] [Indexed: 12/30/2022]
Abstract
Low dietary calcium (Ca) intake during growth limits peak bone mass but physiological adaptation can prevent this adverse effect. To assess the genetic control on the physiologic response to dietary Ca restriction (RCR), we conducted a study in 51 BXD lines fed either 0.5% (basal) or 0.25% (low) Ca diets from ages 4 to 12 weeks (n = 8/line/diet). Ca absorption (CaAbs), femur bone mineral density (BMD), and bone mineral content (BMC) were examined. ANCOVA with body size as covariate was used to detect significant line and diet main effects, and line-by-diet interactions. Body size-corrected residuals were used for linkage mapping and to estimate heritability (h(2) ). Loci controlling the phenotypes were identified using composite interval mapping on each diet and for the RCR. h(2) of basal phenotypes (0.37-0.43) and their RCR (0.32-0.38) was moderate. For each phenotype, we identified multiple quantitative trait loci (QTL) on each diet and for the RCR. Several loci affected multiple traits: Chr 1 (88.3-90.6 cM, CaAbs, BMC), Chr 4 (45.8-49.2 cM, CaAbs, BMD, BMC), Chr 8 (28.6-31.6 cM, CaAbs, BMD, RCR), and Chr 15 (13.6-24 cM, BMD, BMC; 32.3-36 cM, CaAbs RCR, BMD). This suggests that gene clusters may regulate interdependent bone-related phenotypes. Using in silico expression QTL (eQTL) mapping and bioinformatic tools, we identified novel candidates for the regulation of bone under Ca stress (Ext1, Deptor), and for the first time, we report genes modulating Ca absorption (Inadl, Sc4mol, Sh3rf1, and Dennd3), and both Ca and bone metabolism (Tceanc2, Tll1, and Aadat). Our data reveal gene-by-diet interactions and the existence of novel relationships between bone and Ca metabolism during growth. © 2015 American Society for Bone and Mineral Research.
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Affiliation(s)
| | - Rebecca A Replogle
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Libo Wang
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - Min Zhang
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - James C Fleet
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
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High-throughput phenotyping and genetic linkage of cortical bone microstructure in the mouse. BMC Genomics 2015; 16:493. [PMID: 26138817 PMCID: PMC4490749 DOI: 10.1186/s12864-015-1617-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 05/05/2015] [Indexed: 11/16/2022] Open
Abstract
Background Understanding cellular structure and organization, which plays an important role in biological systems ranging from mechanosensation to neural organization, is a complicated multifactorial problem depending on genetics, environmental factors, and stochastic processes. Isolating these factors necessitates the measurement and sensitive quantification of many samples in a reliable, high-throughput, unbiased manner. In this manuscript we present a pipelined approach using a fully automated framework based on Synchrotron-based X-ray Tomographic Microscopy (SRXTM) for performing a full 3D characterization of millions of substructures. Results We demonstrate the framework on a genetic study on the femur bones of in-bred mice. We measured 1300 femurs from a F2 cross experiment in mice without the growth hormone (which can confound many of the smaller structural differences between strains) and characterized more than 50 million osteocyte lacunae (cell-sized hollows in the bone). The results were then correlated with genetic markers in a process called quantitative trait localization (QTL). Our findings provide a mapping between regions of the genome (all 19 autosomes) and observable phenotypes which could explain between 8–40 % of the variance using between 2–10 loci for each trait. This map shows 4 areas of overlap with previous studies looking at bone strength and 3 areas not previously associated with bone. Conclusions The mapping of microstructural phenotypes provides a starting point for both structure-function and genetic studies on murine bone structure and the specific loci can be investigated in more detail to identify single gene candidates which can then be translated to human investigations. The flexible infrastructure offers a full spectrum of shape, distribution, and connectivity metrics for cellular networks and can be adapted to a wide variety of materials ranging from plant roots to lung tissue in studies requiring high sample counts and sensitive metrics such as the drug-gene interactions and high-throughput screening. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1617-y) contains supplementary material, which is available to authorized users.
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Ozcivici E, Zhang W, Donahue LR, Judex S. Quantitative trait loci that modulate trabecular bone's risk of failure during unloading and reloading. Bone 2014; 64:25-32. [PMID: 24698783 DOI: 10.1016/j.bone.2014.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 02/01/2014] [Accepted: 03/22/2014] [Indexed: 01/23/2023]
Abstract
Genetic makeup of an individual is a strong determinant of the morphologic and mechanical properties of bone. Here, in an effort to identify quantitative trait loci (QTLs) for changes in the simulated mechanical parameters of trabecular bone during altered mechanical demand, we subjected 352 second generation female adult (16 weeks old) BALBxC3H mice to 3 weeks of hindlimb unloading followed by 3 weeks of reambulation. Longitudinal in vivo microcomputed tomography (μCT) scans tracked trabecular changes in the distal femur. Tomographies were directly translated into finite element (FE) models and subjected to a uniaxial compression test. Apparent trabecular stiffness and components of the Von Mises (VM) stress distributions were computed for the distal metaphysis and associated with QTLs. At baseline, five QTLs explained 20% of the variation in trabecular peak stresses across the mouse population. During unloading, three QTLs accounted for 14% of the variability in peak stresses. During reambulation, one QTL accounted for 5% of the variability in peak stresses. QTLs were also identified for mechanically induced changes in stiffness, median stress values and skewness of stress distributions. There was little overlap between QTLs identified for baseline and QTLs for longitudinal changes in mechanical properties, suggesting that distinct genes may be responsible for the mechanical response of trabecular bone. Unloading related QTLs were also different from reambulation related QTLs. Further, QTLs identified here for mechanical properties differed from previously identified QTLs for trabecular morphology, perhaps revealing novel gene targets for reducing fracture risk in individuals exposed to unloading and for maximizing the recovery of trabecular bone's mechanical properties during reambulation.
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Affiliation(s)
- Engin Ozcivici
- Department of Mechanical Engineering, Izmir Institute of Technology, Urla, Izmir 35430, Turkey.
| | | | | | - Stefan Judex
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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Edderkaoui B, Kesavan C, Baylink DJ, Wergedal JE, Srivastava AK, Mohan S. ENU mutation mapped to a distal region of chromosome 11 is a major determinant of bone size. Physiol Genomics 2013; 45:1222-8. [PMID: 24151243 DOI: 10.1152/physiolgenomics.00142.2013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using a phenotype driven n-ethyl-nitrosourea (ENU) screen in growth hormone-deficient mice, we have identified a mutant (named 14104) that exhibited a smaller bone size. Phenotype measurements by microcomputed tomography revealed that mutant mice exhibited a 43 and 34% reduction in tissue area and bone area, respectively at the femur middiaphysis. Dynamic histomorphometry revealed a 30 and 15% lower bone formation rate at the periosteal and endosteal surface, respectively. Breaking strength of the femur was reduced by 30% in the mutant mice. To determine if the 14104 locus is involved in a mechanical loading signaling pathway, the skeletal anabolic response to tibia axial loading was evaluated. The increase in trabecular response in the loaded region was severely compromised by the 14014 mutation. To identify the location of mutation, we performed linkage analysis using 62 polymorphic markers in the B6-DBA/2J F2 mice. The genome-wide linkage analysis identified the location of the mutation to a 72 to 83 cM region on chromosome 11 with peak logarithm of the odds scores of 15 for periosteal circumference at marker D11mit338. Sequence analysis revealed no mutation in the coding region of 11 potential candidate genes. Based on these data and published data on the skeletal phenotype of genes in this region, we concluded that the 109-119 Mb region of chromosome 11 harbors a bone size gene that regulates periosteal bone formation. The mutant strain developed in this study provides an important tool to identify a novel mechanosensitive gene that determines bone size during postnatal development.
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Affiliation(s)
- Bouchra Edderkaoui
- Musculoskeletal Disease Center, Loma Linda VA Health Care Systems, Loma Linda, California
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Liu F, Fang F, Yuan H, Yang D, Chen Y, Williams L, Goldstein SA, Krebsbach PH, Guan JL. Suppression of autophagy by FIP200 deletion leads to osteopenia in mice through the inhibition of osteoblast terminal differentiation. J Bone Miner Res 2013; 28:2414-30. [PMID: 23633228 PMCID: PMC3805719 DOI: 10.1002/jbmr.1971] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 03/21/2013] [Accepted: 04/15/2013] [Indexed: 12/22/2022]
Abstract
Autophagy is a conserved lysosomal degradation process that has important roles in both normal human physiology and disease. However, the function of autophagy in bone homeostasis is not well understood. Here, we report that autophagy is activated during osteoblast differentiation. Ablation of focal adhesion kinase family interacting protein of 200 kD (FIP200), an essential component of mammalian autophagy, led to multiple autophagic defects in osteoblasts including aberrantly increased p62 expression, deficient LC3-II conversion, defective autophagy flux, absence of GFP-LC3 puncta in FIP200-null osteoblasts expressing transgenic GFP-LC3, and absence of autophagosome-like structures by electron microscope examination. Osteoblast-specific deletion of FIP200 led to osteopenia in mice. Histomorphometric analysis revealed that the osteopenia was the result of cell-autonomous effects of FIP200 deletion on osteoblasts. FIP200 deletion led to defective osteoblast terminal differentiation in both primary bone marrow and calvarial osteoblasts in vitro. Interestingly, both proliferation and differentiation were not adversely affected by FIP200 deletion in early cultures. However, FIP200 deletion led to defective osteoblast nodule formation after initial proliferation and differentiation. Furthermore, treatment with autophagy inhibitors recapitulated the effects of FIP200 deletion on osteoblast differentiation. Taken together, these data identify FIP200 as an important regulator of bone development and reveal a novel role of autophagy in osteoblast function through its positive role in supporting osteoblast nodule formation and differentiation.
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Affiliation(s)
- Fei Liu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry
| | - Fang Fang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry
| | - Hebao Yuan
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry
| | - Dongye Yang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry
| | - Yongqiang Chen
- Division of Molecular Medicine and Genetics, Department of Internal Medicine
| | - Linford Williams
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry
| | - Steven A. Goldstein
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan Medical School, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Paul H. Krebsbach
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry
| | - Jun-Lin Guan
- Division of Molecular Medicine and Genetics, Department of Internal Medicine
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12
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Burke DT, Kozloff KM, Chen S, West JL, Wilkowski JM, Goldstein SA, Miller RA, Galecki AT. Dissection of complex adult traits in a mouse synthetic population. Genome Res 2012; 22:1549-57. [PMID: 22588897 PMCID: PMC3409268 DOI: 10.1101/gr.135582.111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Finding the causative genetic variations that underlie complex adult traits is a significant experimental challenge. The unbiased search strategy of genome-wide association (GWAS) has been used extensively in recent human population studies. These efforts, however, typically find only a minor fraction of the genetic loci that are predicted to affect variation. As an experimental model for the analysis of adult polygenic traits, we measured a mouse population for multiple phenotypes and conducted a genome-wide search for effector loci. Complex adult phenotypes, related to body size and bone structure, were measured as component phenotypes, and each subphenotype was associated with a genomic spectrum of candidate effector loci. The strategy successfully detected several loci for the phenotypes, at genome-wide significance, using a single, modest-sized population (N = 505). The effector loci each explain 2%–10% of the measured trait variation and, taken together, the loci can account for over 25% of a trait's total population variation. A replicate population (N = 378) was used to confirm initially observed loci for one trait (femur length), and, when the two groups were merged, the combined population demonstrated increased power to detect loci. In contrast to human population studies, our mouse genome-wide searches find loci that individually explain a larger fraction of the observed variation. Also, the additive effects of our detected mouse loci more closely match the predicted genetic component of variation. The genetic loci discovered are logical candidates for components of the genetic networks having evolutionary conservation with human biology.
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Affiliation(s)
- David T Burke
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109, USA.
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13
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Zhang P, Yokota H. Knee loading stimulates healing of mouse bone wounds in a femur neck. Bone 2011; 49:867-72. [PMID: 21723427 PMCID: PMC3167009 DOI: 10.1016/j.bone.2011.06.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/14/2011] [Accepted: 06/17/2011] [Indexed: 11/17/2022]
Abstract
Healing of bone wounds is sensitive to various environmental stimuli. Using knee loading, which has been shown to stimulate bone formation in mouse femora and tibiae, we addressed a question: Does knee loading accelerate a closure of open wounds in a femur neck? A surgical wound (0.5 mm in diameter) was generated at the femur neck in the left and right femora of C57/BL/6 female mice, and knee loading was applied to the left knee for 3 min/day for 3 consecutive days. Surgical holes at the femoral midshaft were used as control. Animals were sacrificed 1, 2, and 3 weeks after surgery for analyses with μCT and pQCT as well as mechanical testing. The results showed load-driven acceleration of the closure of surgical holes. Compared to a sham-loaded contralateral control, knee loading reduced the size of surgical wounds in the femoral midshaft by 14% (p<0.05), 21% (p<0.01), and 32% (p<0.001) in 1, 2, and 3 weeks, respectively. It also decreased the wound size in the femur neck by 16% (p<0.001; 1 week), 18% (p<0.001; 2 weeks), and 21% (p<0.001; 3 weeks). Images with pQCT revealed that bone mineral density (BMD) was increased from 571±19 mg/cm(3) (control) to 686±19 mg/cm(3) (loaded) (p<0.01), and bone mineral content (BMC) from 3.05±0.12 mg/mm (control) to 3.42±0.11 mg/mm (loaded) (p<0.05). Furthermore, mechanical testing showed that stiffness of the femur was increased by knee loading (p<0.05). This study demonstrates that knee loading is capable of accelerating healing of surgical wounds throughout the femur including the femoral midshaft and neck.
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Affiliation(s)
- Ping Zhang
- Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202
- Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Hiroki Yokota
- Biomedical Engineering, Indiana University Purdue University Indianapolis, IN 46202
- Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202
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14
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Farber CR, Kelly SA, Baruch E, Yu D, Hua K, Nehrenberg DL, de Villena FPM, Buus RJ, Garland T, Pomp D. Identification of quantitative trait loci influencing skeletal architecture in mice: emergence of Cdh11 as a primary candidate gene regulating femoral morphology. J Bone Miner Res 2011; 26:2174-83. [PMID: 21638317 PMCID: PMC3304441 DOI: 10.1002/jbmr.436] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Bone strength is influenced by many properties intrinsic to bone, including its mass, geometry, and mineralization. To further advance our understanding of the genetic basis of bone-strength-related traits, we used a large (n = 815), moderately (G(4) ) advanced intercross line (AIL) of mice derived from a high-runner selection line (HR) and the C57BL/6J inbred strain. In total, 16 quantitative trait loci (QTLs) were identified that affected areal bone mineral density (aBMD) and femoral length and width. Four significant (p < .05) and one suggestive (p < .10) QTLs were identified for three aBMD measurements: total body, vertebral, and femoral. A QTL on chromosome (Chr.) 3 influenced all three aBMD measures, whereas the other four QTLs were unique to a single measure. A total of 10 significant and one suggestive QTLs were identified for femoral length (FL) and two measures of femoral width, anteroposterior (AP) and mediolateral (ML). FL QTLs were distinct from loci affecting AP and ML width, and of the 7 AP QTLs, only three affected ML. A QTL on Chr. 8 that explained 7.1% and 4.0% of the variance in AP and ML, respectively, was mapped to a 6-Mb region harboring 12 protein-coding genes. The pattern of haplotype diversity across the QTL region and expression profiles of QTL genes suggested that of the 12, cadherin 11 (Cdh11) was most likely the causal gene. These findings, when combined with existing data from gene knockouts, identify Cdh11 as a strong candidate gene within which genetic variation may affect bone morphology.
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Affiliation(s)
- Charles R Farber
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA.
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15
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Abstract
BACKGROUND The skeleton plays a critical structural role in bearing functional loads, and failure to do so results in fracture. As we evaluate new therapeutics and consider treatments to prevent skeletal fractures, understanding the basic mechanics underlying whole bone testing and the key principles and characteristics contributing to the structural strength of a bone is critical. QUESTIONS/PURPOSES We therefore asked: (1) How are whole bone mechanical tests performed and what are the key outcomes measured? (2) How do the intrinsic characteristics of bone tissue contribute to the mechanical properties of a whole bone? (3) What are the effects of extrinsic characteristics on whole bone mechanical behavior? (4) Do environmental factors affect whole bone mechanical properties? METHODS We conducted a PubMed search using specific search terms and limiting our included articles to those related to in vitro testing of whole bones. Basic solid mechanics concepts are summarized in the context of whole bone testing and the determinants of whole bone behavior. RESULTS Whole bone mechanical tests measure structural stiffness and strength from load-deformation data. Whole bone stiffness and strength are a function of total bone mass and the tissue geometric distribution and material properties. Age, sex, genetics, diet, and activity contribute to bone structural performance and affect the incidence of skeletal fractures. CONCLUSIONS Understanding and preventing skeletal fractures is clinically important. Laboratory tests of whole bone strength are currently the only measures for in vivo fracture prediction. In the future, combined imaging and engineering models may be able to predict whole bone strength noninvasively.
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Lagerholm S, Park HB, Luthman H, Grynpas M, McGuigan F, Swanberg M, Åkesson K. Identification of candidate gene regions in the rat by co-localization of QTLs for bone density, size, structure and strength. PLoS One 2011; 6:e22462. [PMID: 21818327 PMCID: PMC3144887 DOI: 10.1371/journal.pone.0022462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/25/2011] [Indexed: 12/05/2022] Open
Abstract
Susceptibility to osteoporotic fracture is influenced by genetic factors that can be dissected by whole-genome linkage analysis in experimental animal crosses. The aim of this study was to characterize quantitative trait loci (QTLs) for biomechanical and two-dimensional dual-energy X-ray absorptiometry (DXA) phenotypes in reciprocal F2 crosses between diabetic GK and normo-glycemic F344 rat strains and to identify possible co-localization with previously reported QTLs for bone size and structure. The biomechanical measurements of rat tibia included ultimate force, stiffness and work to failure while DXA was used to characterize tibial area, bone mineral content (BMC) and areal bone mineral density (aBMD). F2 progeny (108 males, 98 females) were genotyped with 192 genome-wide markers followed by sex- and reciprocal cross-separated whole-genome QTL analyses. Significant QTLs were identified on chromosome 8 (tibial area; logarithm of odds (LOD) = 4.7 and BMC; LOD = 4.1) in males and on chromosome 1 (stiffness; LOD = 5.5) in females. No QTLs showed significant sex-specific interactions. In contrast, significant cross-specific interactions were identified on chromosome 2 (aBMD; LOD = 4.7) and chromosome 6 (BMC; LOD = 4.8) for males carrying F344mtDNA, and on chromosome 15 (ultimate force; LOD = 3.9) for males carrying GKmtDNA, confirming the effect of reciprocal cross on osteoporosis-related phenotypes. By combining identified QTLs for biomechanical-, size- and qualitative phenotypes (pQCT and 3D CT) from the same population, overlapping regions were detected on chromosomes 1, 3, 4, 6, 8 and 10. These are strong candidate regions in the search for genetic risk factors for osteoporosis.
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Affiliation(s)
- Sofia Lagerholm
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Hee-Bok Park
- Medical Genetics Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Holger Luthman
- Medical Genetics Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Marc Grynpas
- Institute of Biomaterials and Biomedical Engineering, University of Toronto and Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Canada
| | - Fiona McGuigan
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Maria Swanberg
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Kristina Åkesson
- Clinical and Molecular Osteoporosis Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
- Department of Orthopedics, Skåne University Hospital Malmö, Malmö, Sweden
- * E-mail:
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Miller RA, Kreider J, Galecki A, Goldstein SA. Preservation of femoral bone thickness in middle age predicts survival in genetically heterogeneous mice. Aging Cell 2011; 10:383-91. [PMID: 21276183 DOI: 10.1111/j.1474-9726.2011.00671.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To see whether age-related changes in bone could predict subsequent lifespan, we measured multiple aspects of femur size and shape at 4, 15, and 24 months of age in genetically heterogeneous mice. Mice whose cortical bone became thicker from 4 to 15 months, associated with preservation of the endosteal perimeter, survived longer than mice whose endosteal cavity expanded, at the expense of cortical bone, over this age range. Femur size at age 4 months was also associated with a difference in life expectancy: mice with larger bones (measured by length, cortical thickness, or periosteal perimeter) had shorter lifespans. Femur length, midlife change in cortical bone thickness, and midlife values of CD8 T memory cells each added significant power for longevity prediction. Mice in the upper half of the population for each of these three endpoints lived, on average, 103 days (12%) longer than mice with the opposite characteristics. Thus, measures of young adult bone dimensions, changes as a result of bone remodeling in middle age, and immunological maturation provide partially independent indices of aging processes that together help to determine lifespan in genetically heterogeneous mice.
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Affiliation(s)
- Richard A Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, USA.
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18
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Buck LT, Stock JT, Foley RA. Levels of Intraspecific Variation Within the Catarrhine Skeleton. INT J PRIMATOL 2010. [DOI: 10.1007/s10764-010-9428-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Jepsen KJ, Courtland HW, Nadeau JH. Genetically determined phenotype covariation networks control bone strength. J Bone Miner Res 2010; 25:1581-93. [PMID: 20200957 PMCID: PMC3154000 DOI: 10.1002/jbmr.41] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 08/26/2009] [Accepted: 01/12/2010] [Indexed: 12/31/2022]
Abstract
To identify genes affecting bone strength, we studied how genetic variants regulate components of a phenotypic covariation network that was previously shown to accurately characterize the compensatory trait interactions involved in functional adaptation during growth. Quantitative trait loci (QTLs) regulating femoral robustness, morphologic compensation, and mineralization (tissue quality) were mapped at three ages during growth using AXB/BXA Recombinant Inbred (RI) mouse strains and adult B6-i(A) Chromosome Substitution Strains (CSS). QTLs for robustness were identified on chromosomes 8, 12, 18, and 19 and confirmed at all three ages, indicating that genetic variants established robustness postnatally without further modification. A QTL for morphologic compensation, which was measured as the relationship between cortical area and body weight, was identified on chromosome 8. This QTL limited the amount of bone formed during growth and thus acted as a setpoint for diaphyseal bone mass. Additional QTLs were identified from the CSS analysis. QTLs for robustness and morphologic compensation regulated bone structure independently (ie, in a nonpleiotropic manner), indicating that each trait may be targeted separately to individualize treatments aiming to improve strength. Multiple regression analyses showed that variation in morphologic compensation and tissue quality, not bone size, determined femoral strength relative to body weight. Thus an individual inheriting slender bones will not necessarily inherit weak bones unless the individual also inherits a gene that impairs compensation. This systems genetic analysis showed that genetically determined phenotype covariation networks control bone strength, suggesting that incorporating functional adaptation into genetic analyses will advance our understanding of the genetic basis of bone strength.
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Affiliation(s)
- Karl J Jepsen
- Leni and Peter W May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY 10029, USA.
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20
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Saless N, Lopez Franco GE, Litscher S, Kattappuram RS, Houlihan MJ, Vanderby R, Demant P, Blank RD. Linkage mapping of femoral material properties in a reciprocal intercross of HcB-8 and HcB-23 recombinant mouse strains. Bone 2010; 46:1251-9. [PMID: 20102754 PMCID: PMC2854180 DOI: 10.1016/j.bone.2010.01.375] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 01/15/2010] [Accepted: 01/15/2010] [Indexed: 01/27/2023]
Abstract
Skeletal fragility is an important health problem with a large genetic component. We performed a 603 animal F2 reciprocal intercross of the recombinant congenic strains HcB-8 and HcB-23 to genetically map quantitative trait loci (QTLs) for tissue-level femoral biomechanical performance. These included elastic and post-yield strain, Young's modulus, elastic and maximum stress, and toughness and were calculated from 3-point bend testing of femora by the application of standard beam equations. We mapped these with R/qtl and QTL Cartographer and established significance levels empirically by permutation testing. Significant QTLs for at least one trait are present on chromosomes 1, 6, and 10 in the full F2 population, with additional QTLs evident in subpopulations defined by sex and cross direction. On chromosome 10, we find a QTL for post-yield strain and toughness, phenotypes that have not been mapped previously. Notably, the HcB-8 allele at this QTL increases post-yield strain and toughness, but decreases bone mineral density (BMD), while the material property QTLs on chromosomes 1, 6, and at a second chromosome 10 QTL are independent of BMD. We find significant sex x QTL and cross direction x QTL interactions. A robust, pleiotropic chromosome 4 QTL that we previously reported at the whole-bone level showed no evidence of linkage at the tissue-level, supporting our interpretation that modeling capacity is its primary phenotype. Our data demonstrate an inverse relationship between femoral perimeter and Young's modulus, with R(2)=0.27, supporting the view that geometric and material bone properties are subject to an integrated set of regulatory mechanisms. Mapping QTLs for tissue-level biomechanical performance advances understanding of the genetic basis of bone quality.
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Affiliation(s)
- Neema Saless
- University of Wisconsin, Madison, WI USA
- William S. Middleton Memorial Veterans Hospital, Madison WI USA
| | - Gloria E. Lopez Franco
- University of Wisconsin, Madison, WI USA
- William S. Middleton Memorial Veterans Hospital, Madison WI USA
| | - Suzanne Litscher
- University of Wisconsin, Madison, WI USA
- William S. Middleton Memorial Veterans Hospital, Madison WI USA
| | | | | | | | | | - Robert D. Blank
- University of Wisconsin, Madison, WI USA
- William S. Middleton Memorial Veterans Hospital, Madison WI USA
- Corresponding author at: Robert D. Blank, MD, PhD, H4/556 CSC (5148), 600 Highland Ave., Madison, WI 53792-5148, USA, 608-262-5586 (phone), 608-263-9983 (fax),
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21
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Jepsen KJ. Systems analysis of bone. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2009; 1:73-88. [PMID: 20046860 PMCID: PMC2790199 DOI: 10.1002/wsbm.15] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The genetic variants contributing to variability in skeletal traits has been well studied, and several hundred QTLs have been mapped and several genes contributing to trait variation have been identified. However, many questions remain unanswered. In particular, it is unclear whether variation in a single gene leads to alterations in function. Bone is a highly adaptive system and genetic variants affecting one trait are often accompanied by compensatory changes in other traits. The functional interactions among traits, which is known as phenotypic integration, has been observed in many biological systems, including bone. Phenotypic integration is a property of bone that is critically important for establishing a mechanically functional structure that is capable of supporting the forces imparted during daily activities. In this paper, bone is reviewed as a system and primarily in the context of functionality. A better understanding of the system properties of bone will lead to novel targets for future genetic analyses and the identification of genes that are directly responsible for regulating bone strength. This systems analysis has the added benefit of leaving a trail of valuable information about how the skeletal system works. This information will provide novel approaches to assessing skeletal health during growth and aging and for developing novel treatment strategies to reduce the morbidity and mortality associated with fragility fractures.
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Affiliation(s)
- Karl J Jepsen
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY 10029
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22
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Leung KS, Shi HF, Cheung WH, Qin L, Ng WK, Tam KF, Tang N. Low-magnitude high-frequency vibration accelerates callus formation, mineralization, and fracture healing in rats. J Orthop Res 2009; 27:458-65. [PMID: 18924140 DOI: 10.1002/jor.20753] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fracture healing is a biological regenerative process that follows a well-orchestrated sequence. Most healing is uneventful and enhancement of normal fracture healing is not commonly done, although it is clinically important in the recovery and regain of functions after fracture. This study investigated the osteogenic effect of low-magnitude high-frequency vibration (LMHFV, 35 Hz, 0.3 g) on the enhancement of fracture healing in rats with closed femoral shaft fracture by comparing with sham-treated control. Assessments with plain radiography, micro-CT as well as histomorphometry showed that the amount of callus was significantly larger (p = 0.001 for callus area, 2 weeks posttreatment); the remodeling of the callus into mature bone was significantly faster (p = 0.039, 4 weeks posttreatment) in the treatment group. The mechanical strength of the healed fracture in the treatment group at 4 weeks was significantly greater (p < 0.001). The results showed the acceleration of callus formation, mineralization, and fracture healing in the treatment group. It is concluded that LMHFV enhances healing in the closed femoral shaft fracture in rats. The potential clinical advantages shall be confirmed in the subsequent clinical trials.
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Affiliation(s)
- Kwok Sui Leung
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China.
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23
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Saless N, Litscher SJ, Lopez Franco GE, Houlihan MJ, Sudhakaran S, Raheem KA, O'Neil TK, Vanderby R, Demant P, Blank RD. Quantitative trait loci for biomechanical performance and femoral geometry in an intercross of recombinant congenic mice: restriction of the Bmd7 candidate interval. FASEB J 2009; 23:2142-54. [PMID: 19261723 DOI: 10.1096/fj.08-118679] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Despite steady progress in identifying quantitative trait loci (QTLs) for bone phenotypes, relatively little progress has been made in moving from QTLs to identifying the relevant gene. We exploited the genetic structure of recombinant congenic mouse strains by performing a reciprocal intercross of the strains HcB-8 and HcB-23, phenotyped for body size, femoral biomechanical performance, and femoral diaphyseal geometry and mapped with R/qtl and QTL Cartographer. Significant QTLs are present on chromosomes 1, 2, 3, 4, 6, and 10. We found significant sex x QTL and cross-direction x QTL interactions. The chromosome 4 QTL affects multiple femoral anatomic features and biomechanical properties. The known segregating segment of chromosome 4 contains only 18 genes, among which Ece1, encoding endothelin-converting enzyme 1, stands out as a candidate. Endothelin signaling has been shown to promote the growth of osteoblastic metastases and to potentiate signaling via the Wnt pathway. The colocalizing chromosome 4 QTL Bmd7 (for bone mineral density 7) increases responsiveness to mechanical loading. By exploiting the short informative segment of chromosome 4 and the known biology, we propose that Ece1 is the gene responsible for Bmd7 and that it acts by increasing responsiveness to mechanical loading through modulation of Wnt signaling.
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Affiliation(s)
- Neema Saless
- University of Wisconsin, Madison, Wisconsin, USA
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Identification of quantitative trait loci affecting murine long bone length in a two-generation intercross of LG/J and SM/J Mice. J Bone Miner Res 2008; 23:887-95. [PMID: 18435578 PMCID: PMC2677087 DOI: 10.1359/jbmr.080210] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Study of mutations with large phenotypic effects has allowed the identification of key players in skeletal development. However, the molecular nature of variation in large, phenotypically normal populations tends to be characterized by smaller phenotypic effects that remain undefined. MATERIALS AND METHODS We use interval mapping and quantitative trait locus (QTL) mapping techniques in the combined F2-F3 populations (n = 2111) of an LG/J x SM/J mouse intercross to detect QTLs associated with the lengths of the humerus, ulna, femur, and tibia. RESULTS Seventy individual trait QTLs affecting long bone lengths were detected, with several chromosomes harboring multiple QTLs. The genetic architecture suggests mainly small, additive effects on long bone length, with roughly one third of the QTLs displaying dominance. Sex interactions were common, and four sex-specific QTLs were observed. Pleiotropy could not be rejected for most of the QTLs identified. Thirty-one epistatic interactions were detected, almost all affecting regions including or immediately adjacent to QTLs. CONCLUSIONS A complex regulatory network with many gene interactions modulates bone growth, possibly with integrated skeletal modules that allow fine-tuning of developmental processes present. Candidate genes in the QTL CIs include many genes known to affect endochondral bone growth and genes that have not yet been associated with bone growth or body size but have a strong potential to influence these traits.
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Abstract
The risk of osteoporotic fracture can be viewed as a function of loading conditions and the ability of the bone to withstand the load. Skeletal loads are dominated by muscle action. Recently, it has become clear that bone and muscle share genetic determinants. Involution of the musculoskeletal system manifests as bone loss (osteoporosis) and muscle wasting (sarcopenia). Therefore, the consideration of pleiotropy is an important aspect in the study of the genetics of osteoporosis and sarcopenia. This Perspective will provide the evidence for a shared genetic influence on bone and muscle. We will start with an overview of accumulating evidence that physical exercise produces effects on the adult skeleton, seeking to unravel some of the contradictory findings published thus far. We will provide indications that there are pleiotropic relationships between bone structure/mass and muscle mass/function. Finally, we will offer some insights and practical recommendations as to the value of studying shared genetic factors and will explore possible directions for future research. We consider several related questions that together comprise the general paradigm of bone responses to mechanical loading and the relationship between muscle strength and bone parameters, including the genetic factors that modulate these responses. We believe that further progress in understanding the common genetic etiology of osteoporosis and sarcopenia will provide valuable insight into important biological underpinnings for both conditions and may translate into new approaches to reduce the burdens of both conditions through improved diagnosis, prevention, and early targeted treatment.
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O'Neill MC, Dobson SD. The degree and pattern of phylogenetic signal in primate long-bone structure. J Hum Evol 2008; 54:309-22. [DOI: 10.1016/j.jhevol.2007.08.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Revised: 04/09/2007] [Accepted: 08/25/2007] [Indexed: 11/24/2022]
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Tatsumi S, Ito M, Asaba Y, Tsutsumi K, Ikeda K. Life-long caloric restriction reveals biphasic and dimorphic effects on bone metabolism in rodents. Endocrinology 2008; 149:634-41. [PMID: 17991723 DOI: 10.1210/en.2007-1089] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Caloric restriction (CR) extends the lifespan of various organisms and slows the onset of age-related disorders; however, little is known about the long-term effects of CR per se on bone. In the present study, we have examined the effects of life-long CR vs. ad libitum (AD) feeding, mainly on the trabecular bone of proximal tibiae in male C57BL/6 mice and F344 rats. Micro-computed tomography scanning of tibiae revealed that CR for 3-9 months caused a substantial decrease in three-dimensional bone volume with structural derangements. Bone histomorphometry revealed the reduced bone mass was due mainly to suppression of bone formation. In db/db mice with defective leptin receptor, CR was unable to decrease bone mass and suppress bone formation. The effect of CR on bone mass was inhibited by administration of a beta-adrenergic blocker, propranolol. Thus, CR may regulate bone formation through leptin signaling and elevated sympathetic nervous tone. Interestingly, the difference in bone volume between the CR and AD groups disappeared after 1 yr of age, and mice and rats on an additional extension of CR to natural death maintained higher bone mass than the AD groups, with reduced bone turnover, suggesting that CR slows skeletal aging by regulating the rate of bone turnover. This is the first report, to our knowledge, that has examined the effects of lifelong CR on bone metabolism and trabecular microstructure and documents its contrasting effects during maturation vs. the postmaturational, involutional period.
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Affiliation(s)
- Sawako Tatsumi
- Department of Bone and Joint Disease, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Morioka, Obu, Aichi, Japan
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Karasik D, Dupuis J, Cupples LA, Beck TJ, Mahaney MC, Havill LM, Kiel DP, Demissie S. Bivariate linkage study of proximal hip geometry and body size indices: the Framingham study. Calcif Tissue Int 2007; 81:162-73. [PMID: 17674073 PMCID: PMC2376749 DOI: 10.1007/s00223-007-9052-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 06/13/2007] [Indexed: 02/05/2023]
Abstract
Femoral geometry and body size are both characterized by substantial heritability. The purpose of this study was to discern whether hip geometry and body size (height and body mass index, BMI) share quantitative trait loci (QTL). Dual-energy X-ray absorptiometric scans of the proximal femur from 1,473 members in 323 pedigrees (ages 31-96 years) from the Framingham Osteoporosis Study were studied. We measured femoral neck length, neck-shaft angle, subperiosteal width (outer diameter), cross-sectional bone area, and section modulus, at the narrowest section of the femoral neck (NN), intertrochanteric (IT), and femoral shaft (S) regions. In variance component analyses, genetic correlations (rho ( G )) between hip geometry traits and height ranged 0.30-0.59 and between hip geometry and BMI ranged 0.11-0.47. In a genomewide linkage scan with 636 markers, we obtained nominally suggestive linkages (bivariate LOD scores > or =1.9) for geometric traits and either height or BMI at several chromosomes (4, 6, 9, 15, and 21). Two loci, on chr. 2 (80 cM, BMI/shaft section modulus) and chr. X (height/shaft outer diameter), yielded bivariate LOD scores > or =3.0; although these loci were linked in univariate analyses with a geometric trait, neither was linked with either height or BMI. In conclusion, substantial genetic correlations were found between the femoral geometric traits, height and BMI. Linkage signals from bivariate linkage analyses of bone geometric indices and body size were similar to those obtained in univariate linkage analyses of femoral geometric traits, suggesting that most of the detected QTL primarily influence geometry of the hip.
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Affiliation(s)
- D Karasik
- Hebrew SeniorLife Institute for Aging Research and Harvard Medical School, 1200 Centre Street, Boston, MA 02131, USA.
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Ruff C, Holt B, Trinkaus E. Who's afraid of the big bad Wolff?: "Wolff's law" and bone functional adaptation. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2007; 129:484-98. [PMID: 16425178 DOI: 10.1002/ajpa.20371] [Citation(s) in RCA: 499] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
"Wolff's law" is a concept that has sometimes been misrepresented, and frequently misunderstood, in the anthropological literature. Although it was originally formulated in a strict mathematical sense that has since been discredited, the more general concept of "bone functional adaptation" to mechanical loading (a designation that should probably replace "Wolff's law") is supported by much experimental and observational data. Objections raised to earlier studies of bone functional adaptation have largely been addressed by more recent and better-controlled studies. While the bone morphological response to mechanical strains is reduced in adults relative to juveniles, claims that adult morphology reflects only juvenile loadings are greatly exaggerated. Similarly, while there are important genetic influences on bone development and on the nature of bone's response to mechanical loading, variations in loadings themselves are equally if not more important in determining variations in morphology, especially in comparisons between closely related individuals or species. The correspondence between bone strain patterns and bone structure is variable, depending on skeletal location and the general mechanical environment (e.g., distal vs. proximal limb elements, cursorial vs. noncursorial animals), so that mechanical/behavioral inferences based on structure alone should be limited to corresponding skeletal regions and animals with similar basic mechanical designs. Within such comparisons, traditional geometric parameters (such as second moments of area and section moduli) still give the best available estimates of in vivo mechanical competence. Thus, when employed with appropriate caution, these features may be used to reconstruct mechanical loadings and behavioral differences within and between past populations.
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Affiliation(s)
- Christopher Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Otsuki B, Matsumura T, Shimizu M, Mori M, Okudaira S, Nakanishi R, Higuchi K, Hosokawa M, Tsuboyama T, Nakamura T. Quantitative trait locus that determines the cross-sectional shape of the femur in SAMP6 and SAMP2 mice. J Bone Miner Res 2007; 22:675-85. [PMID: 17295603 DOI: 10.1359/jbmr.070206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED We segregated a QTL on chromosome 11 that affects femoral cross-sectional shape during growth by generating a congenic strain and an additional 16 subcongenic strains of the senescence-accelerated mouse strain, SAMP6. The QTL region was narrowed down to a 10.0-Mbp region. INTRODUCTION Genetic background is known to affect bone characteristics. However, little is known about how polymorphic genes modulate bone shape. In a previous study using SAMP2 and SAMP6 mice, we reported a quantitative trait locus (QTL) on chromosome (Chr) 11 that had significant linkage to peak relative bone mass in terms of cortical thickness index (CTI) in male mice. We named it Pbd1. Here we aimed to clarify the effects of Pbd1 on skeletal phenotype in male mice and to narrow down the QTL region. MATERIALS AND METHODS We generated a congenic strain named P6.P2-Pbd1(b), carrying a 39-cM SAMP2-derived Chr11 interval on a SAMP6 genetic background. Sixteen subcongenic strains with smaller overlapping intervals on the SAMP6 background were generated from P6.P2-Pbd1(b) to narrow the region of interest. The effects of Pbd1 on bone properties were determined. Gene expression analysis of all candidate genes in Pbd1 was performed using real-time RT-PCR. RESULTS The CTI of strain P6.P2-Pbd1(b) at 16 wk was higher than that of SAMP6. This was not caused by differences in cortical thickness but by cross-sectional shape. Morphological analysis by microCT revealed that the femoral cross-sectional shape of P6.P2-Pbd1(b) (and the other subcongenic strains with higher CTI or bone area fraction [BA/TA]) was more compressed anteroposteriorly than that of SAMP6, which was associated with superior mechanical properties. This feature was formed during bone modeling up to 16 wk of age. Subcongenic strains with a higher CTI showed significant increases in endocortical mineral apposition rate and significant reductions in periosteal mineral apposition rate at 8 wk compared with those of the SAMP6. The Pbd1 locus was successfully narrowed down to a 10.0-Mbp region, and the expression analysis suggested a candidate gene, Cacng4. CONCLUSIONS The Pbd1 affects femoral cross-sectional shape by regulating the rate of endocortical and periosteal bone formation of the femur during postnatal growth.
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Affiliation(s)
- Bungo Otsuki
- Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Edderkaoui B, Baylink DJ, Beamer WG, Wergedal JE, Porte R, Chaudhuri A, Mohan S. Identification of mouse Duffy antigen receptor for chemokines (Darc) as a BMD QTL gene. Genes Dev 2007; 17:577-85. [PMID: 17416748 PMCID: PMC1855174 DOI: 10.1101/gr.6009507] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 02/05/2007] [Indexed: 12/14/2022]
Abstract
It is now well known that bone mineral density (BMD) variance is determined by both genetic and environmental factors. Accordingly, studies in human and animal models have revealed evidence for the presence of several quantitative trait loci (QTL) that contribute to BMD variations. However, the identification of BMD QTL genes remains a big challenge. In the current study, we focused our efforts to identify the BMD candidate gene in chromosome 1 (Chr 1) QTL that was detected from a cross involving high BMD CAST/EiJ (CAST) and low BMD C57BL/6J (B6) mice. To this end, we have combined several approaches including: (1) fine mapping the BMD QTL in Chr 1 of the B6.CAST F2 female mice using a large number of polymorphic markers; (2) the generation of congenic sublines of mice by repeated backcrossing of CAST with B6 mice and phenotype characterization; (3) expression profiling genes in the QTL region; and (4) SNP analyses to identify the mouse Duffy Antigen Receptor for Chemokines (Darc) as a candidate gene for Chr 1 BMD QTL2. We verified the involvement of the Darc protein in BMD variation by evaluating the skeletal phenotype of Darc-knockout mice and congenic sublines of mice carrying small chromosomal segments from CAST BMD QTL. Based on the findings that Darc-antibody blocked formation of multinucleated osteoclasts in vitro and that Darc from CAST binds chemokines, known to regulate osteoclast formation, with reduced affinity compared with Darc from B6 mice, we conclude that Darc regulates BMD negatively by increasing osteoclast formation, and that the genetic association between Darc gene polymorphism and BMD variations in humans merits investigation.
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Affiliation(s)
- Bouchra Edderkaoui
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California 92357, USA
| | - David J. Baylink
- Department of Medicine and Biochemistry, Loma Linda University, Loma Linda, California 92354, USA
| | | | - Jon E. Wergedal
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California 92357, USA
- Department of Medicine and Biochemistry, Loma Linda University, Loma Linda, California 92354, USA
| | - Ryan Porte
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California 92357, USA
| | - Asok Chaudhuri
- Laboratory of Cell Biology, New York Blood Center, New York, New York 10021, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California 92357, USA
- Department of Medicine and Biochemistry, Loma Linda University, Loma Linda, California 92354, USA
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Abstract
Over the past 10 years, many advances have been made in understanding the mechanisms by which genetic factors regulate susceptibility to osteoporosis. It has become clear from studies in man and experimental animals that different genes regulate BMD at different skeletal sites and in men and women. Linkage studies have identified several chromosomal regions that regulate BMD, but only a few causative genes have been discovered so far using this approach. In contrast, significant advances have been made in identifying the genes that cause monogenic bone diseases, and polymorphic variation is some of these genes has been found to contribute to the genetic regulation of BMD in the normal population. Other genes that have been investigated as possible candidates for susceptibility to osteoporosis because of their role in bone biology, such as vitamin D, have yielded mixed results. Many candidate gene association studies have been underpowered, and meta-analysis has been used to try to confirm or refute potential associations and gain a better estimate of their true effect size in the population. Most of the genetic variants that confer susceptibility to osteoporosis remain to be discovered. It is likely that new techniques such as whole-genome association will provide new insights into the genetic determinants of osteoporosis and will help to identify genes of modest effect size. From a clinical standpoint, genetic variants that are found to predispose to osteoporosis will advance our understanding of the pathophysiology of the disease. They could be developed as diagnostic genetic tests or form molecular targets for design of new drugs for the prevention and treatment of osteoporosis and other bone diseases.
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Affiliation(s)
- Omar M E Albagha
- Rheumatology Section, Molecular Medicine Centre, University of Edinburgh School of Molecular and Clinical Medicine, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom.
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Reeves GM, McCreadie BR, Chen S, Galecki AT, Burke DT, Miller RA, Goldstein SA. Quantitative trait loci modulate vertebral morphology and mechanical properties in a population of 18-month-old genetically heterogeneous mice. Bone 2007; 40:433-43. [PMID: 17049325 PMCID: PMC1852531 DOI: 10.1016/j.bone.2006.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 08/14/2006] [Accepted: 08/18/2006] [Indexed: 11/18/2022]
Abstract
The aim of this study was to examine effects of polymorphic genes on vertebral bone morphology and mechanical properties. Genotypes from 525 18-month-old female mice were compared to geometric traits obtained from micro-computed tomography and mechanical properties from compression testing. Genetic markers were associated with traits on at least 13 different chromosomes, demonstrating the complexity of genetic control over vertebral form, function and aging.
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Affiliation(s)
- Grant M. Reeves
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Barbara R. McCreadie
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Shu Chen
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan, USA
| | - Andrzej T. Galecki
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan, USA
| | - David T. Burke
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Richard A. Miller
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pathology, Geriatrics Center, Ann Arbor VA Medical Center, University of Michigan, Ann Arbor, Michigan, USA
| | - Steven A. Goldstein
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan, USA
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Liu YJ, Shen H, Xiao P, Xiong DH, Li LH, Recker RR, Deng HW. Molecular genetic studies of gene identification for osteoporosis: a 2004 update. J Bone Miner Res 2006; 21:1511-35. [PMID: 16995806 PMCID: PMC1829484 DOI: 10.1359/jbmr.051002] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This review summarizes comprehensively the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of December 2004. It is intended to constitute a sequential update of our previously published review covering the available data up to the end of 2002. Evidence from candidate gene association studies and genome-wide linkage studies in humans, as well as quantitative trait locus mapping animal models are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. An important extension of this update is incorporation of functional genomic studies (including DNA microarrays and proteomics) on osteogenesis and osteoporosis, in light of the rapid advances and the promising prospects of the field. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.
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Affiliation(s)
- Yong-Jun Liu
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Hui Shen
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Peng Xiao
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Dong-Hai Xiong
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Li-Hua Li
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Robert R Recker
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Hong-Wen Deng
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, China
- Laboratory of Molecular and Statistical Genetics, College of Life Sciences Hunan Normal University, Changsha, Hunan, China
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Kesavan C, Mohan S, Srivastava AK, Kapoor S, Wergedal JE, Yu H, Baylink DJ. Identification of genetic loci that regulate bone adaptive response to mechanical loading in C57BL/6J and C3H/HeJ mice intercross. Bone 2006; 39:634-43. [PMID: 16713414 DOI: 10.1016/j.bone.2006.03.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 03/14/2006] [Accepted: 03/20/2006] [Indexed: 11/15/2022]
Abstract
Strain-dependent differences in bone adaptive responses to loading among inbred mouse strains suggest that genetic background contributes significantly to adaptation to exercise. To explore the genetic regulation of response to loading, we performed a genome-wide search for linkage in a cross between two strains, a good responder, C57BL6/J (B6), and a poor responder, C3H/HeJ (C3H). Using a four-point bending model, the right tibia was loaded by applying 9 N force for 36 cycles for 12 days in 10-week-old female B6xC3H F2 mice. Changes in bone density (BMD) and bone size were evaluated in vivo by pQCT. Measurements from non-loaded left tibia were used as an internal control to calculate loading-induced percent increase in BMD and bone size, thus excluding the possibility of identifying background QTL(s) due to natural allelic variation in mapping strains. A genome-wide scan was performed using 111 microsatellite markers in DNA samples collected from 329 F2 mice. Heritability of bone adaptive response to loading was between 70 and 80%. The mean increase, expressed as percent of unloaded tibia, was 5% for BMD, 9% for periosteal circumference (PC), and 14% for cortical thickness in F2 mice (n = 329). All these phenotypes showed normal distributions. Absence of significant correlation between BMD response to four-point bending and body weight or bone size suggested that the bone adaptive response was independent of bone size. Interval mapping revealed that BMD response to four-point bending was influenced by three significant loci on Chrs 1 (log-of-odds ratio score (LOD) 3.4, 91.8 cM), 3 (LOD 3.6, 50.3 cM), and 8 (LOD 4.2, 60.1 cM) and one suggestive QTL on Chr 9 (LOD 2.5, 33.9 cM). Loading-induced increases in PC and Cth were influenced by four significant loci on Chrs 8 (LOD 3.0, 68.9 cM), 9 (LOD 3.0, 13.1 cM), 17 (LOD 3.0, 39.3 cM), and 18 (LOD 3.0, 0 cM) and two suggestive loci on Chr 9 (LOD 2.2, 24 cM) and 11 (LOD 2.1, 69.9 cM). Pairwise analysis showed the presence of several significant and suggestive interactions between loci on Chrs 1, 3, 8, and 13 for BMD trait. This is the first study that provides evidence for the presence of multiple genetic loci regulating bone anabolic responses to loading in the B6xC3H intercross. Knowledge of the genes underlying these loci could provide novel approaches to improve skeletal mass.
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Affiliation(s)
- Chandrasekhar Kesavan
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, Loma Linda, CA 92357, USA
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Lewis G, Xu J, Dunne N, Daly C, Orr J. Critical comparison of two methods for the determination of nanomechanical properties of a material: Application to synthetic and natural biomaterials. J Biomed Mater Res B Appl Biomater 2006; 78:312-7. [PMID: 16470815 DOI: 10.1002/jbm.b.30489] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two methods used for determining the elastic modulus (E) and hardness (H) of a material--the original version of the well-known Oliver-Pharr Method, OOPM, and a variant of it called the Modified Slopes Method, MSM--were critically compared. The nanoindentation test results, of indenter load-versus-indenter displacement, were recorded for six series of specimens, three of commercially-available acrylic bone cements (Palacos R and Cemex XL) and three of bones (human, bovine, and mouse). In the first series, the specimens were prepared from Palacos R cement mantles retrieved from cemented total hip joint replacements after 11 months, 11 years, and 21 years in vivo. In the second and third series, the specimens were fabricated from hand- and vacuum-mixed dough of Cemex XL cement, respectively. In the fourth, fifth, and sixth series, the specimens were prepared from fresh frozen cortical bone of human tibia, plexiform bone from fresh bovine tibia, and femora from inbred mice, respectively. It was found that, for a given material, the values of E or H computed using OOPM and MSM are not significantly different. However, the recommendation is that MSM is preferable because it is straightforward-only the nanoindentation measurements and values of constants that depend on the geometry of the indenter used are needed. In contrast, when the OOPM is used, there is a critical input (the indenter tip area function), whose computation is problematic. The article also includes a succinct discussion of factors that affect the values of material properties computed from nanoindentation measurements, such as the loading rate and the surface roughness of the test specimen.
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Affiliation(s)
- Gladius Lewis
- Department of Mechanical Engineering, The University of Memphis, Tennessee 38152-3180, USA.
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Bower AL, Lang DH, Vogler GP, Vandenbergh DJ, Blizard DA, Stout JT, McClearn GE, Sharkey NA. QTL analysis of trabecular bone in BXD F2 and RI mice. J Bone Miner Res 2006; 21:1267-75. [PMID: 16869725 DOI: 10.1359/jbmr.060501] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED A sample of 693 mice was used to identify regions of the mouse genome associated with trabecular bone architecture as measured using microCT. QTLs for bone in the proximal tibial metaphysis were identified on several chromosomes indicating regions containing genes that regulate properties of trabecular bone. INTRODUCTION Age-related osteoporosis is a condition of major concern because of the morbidity and mortality associated with osteoporotic fractures in humans. Osteoporosis is characterized by reduced bone density, strength, and altered trabecular architecture, all of which are quantitative traits resulting from the actions of many genes working in concert with each other and the environment over the lifespan. microCT gives accurate measures of trabecular bone architecture providing phenotypic data related to bone volume and trabecular morphology. The primary objective of this research was to identify chromosomal regions called quantitative trait loci (QTLs) that contain genes influencing trabecular architecture as measured by microCT. MATERIALS AND METHODS The study used crosses between C57BL/6J (B6) and DBA/2J (D2) as progenitor strains of a second filial (F2) generation (n = 141 males and 148 females) and 23 BXD recombinant inbred (RI) strains (n approximately 9 of each sex per strain). The proximal tibial metaphyses of the 200-day-old mice were analyzed by microCT to assess phenotypic traits characterizing trabecular bone, including bone volume fraction, trabecular connectivity, and quantitative measures of trabecular orientation and anisotropy. Heritabilities were calculated and QTLs were identified using composite interval mapping. RESULTS A number of phenotypes were found to be highly heritable. Heritability values for measured phenotypes using RI strains ranged from 0.15 for degree of anisotropy in females to 0.51 for connectivity density in females and total volume in males. Significant and confirmed QTLs, with LOD scores 4.3 in the F2 cohort and 1.5 in the corresponding RI cohort were found on chromosomes 1 (43 cM), 5 (44 cM), 6 (20 cM), and 8 (49 cM). Other QTLs with LOD scores ranging from 2.8 to 6.9 in the F2 analyses were found on chromosomes 1, 5, 6, 8, 9, and 12. QTLs were identified using data sets comprised of both male and female quantitative traits, suggesting similar genetic action in both sexes, whereas others seemed to be associated exclusively with one sex or the other, suggesting the possibility of sex-dependent effects. CONCLUSIONS Identification of the genes underlying these QTLs may lead to improvements in recognizing individuals most at risk for developing osteoporosis and in the design of new therapeutic interventions.
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Affiliation(s)
- Abbey L Bower
- The Biomechanics Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802-5702, USA
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Wergedal JE, Ackert-Bicknell CL, Tsaih SW, Sheng MHC, Li R, Mohan S, Beamer WG, Churchill GA, Baylink DJ. Femur mechanical properties in the F2 progeny of an NZB/B1NJ x RF/J cross are regulated predominantly by genetic loci that regulate bone geometry. J Bone Miner Res 2006; 21:1256-66. [PMID: 16869724 DOI: 10.1359/jbmr.060510] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED Genetic analysis of an NZB/B1NJ x RF/J cross has identified QTLs for femur mechanical, geometric, and densitometric phenotypes. Most mechanical QTLs were associated with geometric QTLs, strongly suggesting common genetic regulation. INTRODUCTION Previous studies have shown that bone architecture and BMD are important factors affecting bone strength, and both are genetically regulated. We conducted genetic analyses for loci regulating femur mechanical properties, geometric properties, and BMD in a cohort of F2 mice derived from intercross matings of (NZB/B1NJ x RF/J)F1 parents. MATERIALS AND METHODS Femurs were isolated from 662 10-week-old females. Mechanical properties were determined for a femur from each animal by three-point bending. Geometric properties and volumetric BMD (vBMD) were determined by pQCT. Genotype data were obtained by PCR assays for polymorphic markers carried in the genomic DNA of each mouse. Genome-wide scans were carried out for co-segregation of genetic marker data with values from 23 different phenotypes. Quantitative trait loci (QTLs) were identified for mechanical, geometric, and mineral density phenotypes. RESULTS QTLs for many phenotypes were significantly refined by covariate analyses using body weight and femur length. Major QTLs for mechanical and geometric phenotypes were found on chromosomes 5, 7, 9, 11, and 12. Nine chromosomal locations were identified with mechanical QTLs and 17 locations with one or more geometric QTLs. The significance of five mechanical and nine geometric QTLs was affected by the inclusion of covariates. These changes included both decreases and increases in significance. The QTLs on chromosomes 5 and 12 were decreased by inclusion of the covariates in the analysis, but QTLs on 7 and 11 were unaffected. Mechanical QTLs were almost always associated with geometric QTLs and less commonly (two of six) with vBMD QTLs. CONCLUSIONS Genetic regulation of mechanical properties in the F(2) mice of this NZB/B1NJ x RF/J cross seems to be caused by genes regulating femur geometry.
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Affiliation(s)
- Jon E Wergedal
- Musculoskeletal Disease Center, J. L. Pettis Memorial VA Medical Center, Loma Linda, CA 92357, USA.
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Välimäki VV, Moritz N, Yrjans JJ, Vuorio E, Aro HT. Effect of zoledronic acid on incorporation of a bioceramic bone graft substitute. Bone 2006; 38:432-43. [PMID: 16338190 DOI: 10.1016/j.bone.2005.09.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 09/09/2005] [Accepted: 09/09/2005] [Indexed: 11/25/2022]
Abstract
Many osteoporotic fracture patients are candidates for concurrent treatment with bisphosphonates and bioceramic bone graft substitutes. Osteopromotive silica-based bioactive glasses are known to induce accelerated local bone turnover and adjunct antiresorptive agents, such as zoledronic acid, may affect the process. The current study examined the effect of adjunct zoledronic acid therapy on bioactive glass incorporation. In Harlan Sprague-Dawley rats (n = 80), a standardized region of the proximal tibia was subjected to ablation of local bone marrow and filled with bioactive glass (BG) microspheres. Experimental animals received zoledronic acid (1.5 mug/kg, s.c., once a week, started 1 week before surgery) or doxycycline (a metalloproteinase inhibitor) (33 mg/kg, daily gavage) as a control agent. BG incorporation and geometric bone properties were followed by sequential pQCT imaging. The final outcome at 8 weeks was analyzed by digital radiography, histomorphometry, BEI-SEM, EDXA and muCT. The mRNA levels of markers for bone resorption (cathepsin K, TRACP, MMP-9, MMP-13) and synthesis (type I, II, III collagens, osteocalcin, osteonectin, osteopontin) were measured for determination of local bone turnover. Bones filled with BG microspheres produced 2.5-fold more intramedullary new bone than controls with bone marrow ablation only, but the BG filling delayed the recovery of pQCT strength strain index (SSI) of the bones. Adjunct therapy with zoledronic acid enhanced new bone formation on BG microspheres and particularly improved the SSI values of the BG-filled bones (P < 0.05). The zoledronic acid therapy alone (without BG filling) produced the highest amount of intramedullary new bone (6-fold more than in unfilled controls, P < 0.001) but did not show a similar benefit in SSI. The analyses of mRNA expression confirmed high local bone turnover in all bones with BG filling. At the 9th week of zoledronic acid treatment, bones with and without BG filling showed increased mRNA levels of bone resorption markers and decreased mRNA levels of markers for synthesis, indicating that a corrective resorption process was already in progress in response to massive accumulation of medullary new bone at earlier stages of the therapy. Adjunct antiresorptive therapy seems to be beneficial for incorporation of bioactive glass microspheres and does not block local natural remodeling processes. In the current model, the therapy even resulted in favorable remodeling of the tubular bone structure.
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Affiliation(s)
- Ville-Valtteri Välimäki
- Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, University of Turku, Kiinamyllynkatu 4-8, FIN-20520 Turku, Finland
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Miller RA, Berger SB, Burke DT, Galecki A, Garcia GG, Harper JM, Sadighi Akha AA. T cells in aging mice: genetic, developmental, and biochemical analyses. Immunol Rev 2005; 205:94-103. [PMID: 15882347 DOI: 10.1111/j.0105-2896.2005.00254.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A combination of approaches - gene mapping, biomarker analysis, and studies of signal transduction - has helped to clarify the mechanisms of age-related change in mouse immune status and the implications of immune aging for late-life disease. Mapping studies have documented multiple quantitative trait loci (QTL) that influence the levels of age-sensitive T-cell subsets. Some of these QTL have effects that are demonstrable in young-adult mice (8 months of age) and others demonstrable only in middle-aged mice (18 months). Biomarker studies show that T-cell subset levels measured at 8 or 18 months are significant predictors of lifespan for mice dying of lymphoma, fibrosarcoma, mammary adenocarcinoma, or all causes combined. Mice whose immune systems resemble that of young animals, i.e. with low levels of CD4(+) and CD8(+) memory T cells and relatively high levels of CD4(+) T cells, tend to outlive their siblings with the opposite subset pattern. Biochemical analyses show that T cells from aged mice show defects in the activation process within a few minutes of encountering a stimulus and that the defects precede the recognition by the T-cell receptor of agonist peptides on the antigen-presenting cell. Defective assembly of cytoskeletal fibers and hyperglycosylation of T-cell surface glycoproteins contribute to the immunodeficiency state, and indeed treatment with a sialylglycoprotein endopeptidase can restore full function to CD4(+) T cells from aged donors in vitro.
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Affiliation(s)
- Richard A Miller
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, 48109, USA.
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