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Prondvai E, Kocsis AT, Abourachid A, Adriaens D, Godefroit P, Hu DY, Butler RJ. Radial porosity profiles: a new bone histological method for comparative developmental analysis of diametric limb bone growth. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211893. [PMID: 35582660 PMCID: PMC9091851 DOI: 10.1098/rsos.211893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
In fossil tetrapods, limb bone histology is considered the most reliable tool not only for inferring skeletal maturity-a crucial assessment in palaeobiological and evolutionary studies-but also for evaluating the growth dynamics within the ontogenetic window represented by the primary bone cortex. Due to its complex relationship with bone growth and functional maturation, primary cortical vascularity is an indispensable osteohistological character for reconstructing growth dynamics, especially in the context of various developmental strategies along the precocial-altricial spectrum. Using this concept as our working hypothesis, we developed a new quantitative osteohistological parameter, radial porosity profile (RPP), that captures relative cortical porosity changes in limb bones as trajectories. We built a proof-of-concept RPP dataset on extant birds, then added fossil paravian dinosaurs and performed a set of trajectory-grouping analyses to identify potential RPP categories and evaluate them in the context of our ontogeny-developmental strategy working hypothesis. We found that RPPs, indeed, reflect important developmental features within and across elements, specimens and taxa, supporting their analytical power. Our RPPs also revealed unexpected potential osteohistological correlates of growth and functional development of limb bones. The diverse potential applications of RPPs open up new research directions in the evolution of locomotor ontogeny.
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Affiliation(s)
- Edina Prondvai
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
- MTA-MTM-ELTE Research Group for Paleontology, Budapest, Hungary
| | - Adam T. Kocsis
- Department of Palaeobiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
| | - Anick Abourachid
- Département Adaptations du Vivant, UMR 7179 Muséum National d'Histoire Naturelle – CNRS, Paris, France
| | - Dominique Adriaens
- Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium
| | - Pascal Godefroit
- Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Dong-Yu Hu
- Key Laboratory for Evolution of Past Life in Northeast Asia, Ministry of Land and Resources, Paleontological Institute of Shenyang Normal University, Shenyang, People's Republic of China
- Paleontological Museum of Liaoning, Shenyang, People's Republic of China
| | - Richard J. Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
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McGuire RS, Ourfalian R, Ezell K, Lee AH. Development of limb bone laminarity in the homing pigeon ( Columba livia). PeerJ 2020; 8:e9878. [PMID: 33194361 PMCID: PMC7485507 DOI: 10.7717/peerj.9878] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/14/2020] [Indexed: 12/20/2022] Open
Abstract
Background Birds show adaptations in limb bone shape that are associated with resisting locomotor loads. Whether comparable adaptations occur in the microstructure of avian cortical bone is less clear. One proposed microstructural adaptation is laminar bone in which the proportion of circumferentially-oriented vascular canals (i.e., laminarity) is large. Previous work on adult birds shows elevated laminarity in specific limb elements of some taxa, presumably to resist torsion-induced shear strain during locomotion. However, more recent analyses using improved measurements in adult birds and bats reveal lower laminarity than expected in bones associated with torsional loading. Even so, there may still be support for the resistance hypothesis if laminarity increases with growth and locomotor maturation. Methods Here, we tested that hypothesis using a growth series of 17 homing pigeons (15–563 g). Torsional rigidity and laminarity of limb bones were measured from histological sections sampled from midshaft. Ontogenetic trends in laminarity were assessed using principal component analysis to reduce dimensionality followed by beta regression with a logit link function. Results We found that torsional rigidity of limb bones increases disproportionately with growth, consistent with rapid structural compensation associated with locomotor maturation. However, laminarity decreases with maturity, weakening the hypothesis that high laminarity is a flight adaptation at least in the pigeon. Instead, the histological results suggest that low laminarity, specifically the relative proportion of longitudinal canals aligned with peak principal strains, may better reflect the loading history of a bone.
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Affiliation(s)
- Rylee S McGuire
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
| | - Raffi Ourfalian
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA.,Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA, USA
| | - Kelly Ezell
- Department of Anatomy, College of Graduate Studies, Midwestern University, Glendale, AZ, USA
| | - Andrew H Lee
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA.,Department of Anatomy, College of Graduate Studies, Midwestern University, Glendale, AZ, USA.,College of Veterinary Medicine, Midwestern University, Glendale, AZ, USA
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Ziv E, Milgram J, Davis J, Soares A, Wilde F, Zaslansky P, Shahar R. Neither cortical nor trabecular: An unusual type of bone in the heavy-load-bearing lower pharyngeal jaw of the black drum (Pogonias cromis). Acta Biomater 2020; 104:28-38. [PMID: 31923720 DOI: 10.1016/j.actbio.2020.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/30/2019] [Accepted: 01/02/2020] [Indexed: 10/25/2022]
Abstract
Durophagous fish consume a diet based primarily on hard-shelled animals, mainly mollusks. In order to successfully perform this task, they are equipped with an extra set of jaws located in their throat called pharyngeal jaws. Here we present the results of a study of the structure of the bony material of the exceptionally powerful lower pharyngeal jaws (LPJs) of the black drum Pogonias cromis which generate the highest biting forces documented in bony fishes. In particular, we studied the two long and slender struts that support the entire dental plate and teeth of the LPJ, in order to determine how this structure withstands the huge stresses it encounters repetitively and for long periods of time. We describe the hierarchical structure of the struts of lower pharyngeal jaw of P. cromis at a wide range of length scales, and show how it is adapted to successfully achieve its high mechanical performance. In particular, we show that the bone material of the strut is neither cortical nor cancellous, and although it is highly porous, its complex and layered three-dimensional arrangement of thick lamellae sheets, which are inter-connected by thin plates, is perfectly tailored to withstand extremely large but directionally-consistent forces. STATEMENT OF SIGNIFICANCE: The diet of some fish consists of hard food, like mollusks and shells. In order to accomplish the task of cracking this type of food, they have an extra set of bony jaws located in their throat, called pharyngeal jaws. Here we describe the hierarchical structural elements of these jaws which allow them to withstand huge forces repeatedly over long periods of time. Surprisingly, the structure is very porous, but its architectural design is superbly adapted to handle consistently-oriented forces. This structural motif defines a new bony material which is neither cortical nor cancellous.
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Pitfield R, Deter C, Mahoney P. Bone histomorphometric measures of physical activity in children from medieval England. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 169:730-746. [DOI: 10.1002/ajpa.23853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/18/2019] [Accepted: 04/29/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Rosie Pitfield
- Skeletal Biology Research Centre, School of Anthropology and ConservationUniversity of Kent Canterbury UK
| | - Chris Deter
- Skeletal Biology Research Centre, School of Anthropology and ConservationUniversity of Kent Canterbury UK
| | - Patrick Mahoney
- Skeletal Biology Research Centre, School of Anthropology and ConservationUniversity of Kent Canterbury UK
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Gorustovich AA, Nielsen FH. Effects of Nutritional Deficiency of Boron on the Bones of the Appendicular Skeleton of Mice. Biol Trace Elem Res 2019; 188:221-229. [PMID: 30182352 DOI: 10.1007/s12011-018-1499-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 08/28/2018] [Indexed: 01/20/2023]
Abstract
Scientific evidence has shown the nutritional importance of boron (B) in the remodeling and repair of cancellous bone tissue. However, the effects of the nutritional deficiency of B on the cortical bone tissue of the appendicular skeleton have not yet been described. Thus, a study was performed to histomorphometrically evaluate the density of osteocyte lacunae of cortical bone of mouse femora under conditions of nutritional deficiency of B and to analyze the effects of the deficiency on the biomechanical properties of mouse tibiae. Weaning, 21-day-old male Swiss mice were assigned to the following two groups: controls (B+; n = 10) and experimental (B-; n = 10). Control mice were fed a basal diet containing 3 mg B/kg, whereas experimental mice were fed a B-deficient diet containing 0.07 mg B/kg for 9 weeks. The histological and histomorphometric evaluations of the mice fed a B-deficient diet showed a decrease in the density of osteocyte lacunae in the femoral cortical bone tissue and the evaluation of biomechanical properties showed lower bone rigidity in the tibia.
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Affiliation(s)
- Alejandro A Gorustovich
- Interdisciplinary Materials Group-IESIING-UCASAL, INTECIN UBA-CONICET, A4400EDD, Salta, Argentina.
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Sabolová V, Brinek A, Sládek V. The effect of hydrochloric acid on microstructure of porcine (Sus scrofa domesticus) cortical bone tissue. Forensic Sci Int 2018; 291:260-271. [PMID: 30268052 DOI: 10.1016/j.forsciint.2018.08.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/15/2018] [Accepted: 08/25/2018] [Indexed: 10/28/2022]
Abstract
We evaluated the degradation of cortical bone tissue by hydrochloric acid (HCl) since intentional bone decalcification in a forensic context has not been studied on a histomorphological level. We used 70 pig metatarsal bones split into subsamples and immersed in one of three concentrations of acidic solutions (0.5M, 1M, 2M HCl) for two and four hours. We analyzed the cortical thicknesses on transversal cross-sections, thicknesses of the three histomorphologically distinct zones present in acid-immersed bones, and number and area of crystals present in one of the zones. Furthermore, we analyzed the ratio of calcium to phosphorus (Ca:P). We observed a division of the cortical bone cross section into three distinctive zones: demineralized matrix (DM) in the periosteal part of bone, middle contact zone (CZ), and mineralized matrix (MM) in the endosteal part of bone. With increasing acid concentration and time of immersion (from 0.5M HCl for 2h to 2M HCl for 4h), the thickness of DM increased by 67%, the thickness of CZ increased by 56%, and the thickness of MM decreased by 32%. The Ca:P ratio in the contact zone of acid-treated samples did not change significantly with changing acid concentration and time of immersion. The Ca:P ratio of the CZ decreased by 10% when compared to the Ca:P ratio of MM in acid-treated samples. Moreover, we observed crystals on the outer periosteal border of the DM zone, in the CZ, and in the MM Haversian/Volkmann's canals. The size and number of the crystals in the CZ of acid-treated bones increased with acid concentration and time of acid immersion. Moreover, we also observed significant differences in all analyzed properties between anatomical regions. Due to varying reactions to acid immersion among anatomical regions, bone micro-degradation should be observed separately for each region.
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Affiliation(s)
- Veronika Sabolová
- Faculty of Science, Charles University, Viničná 7, 128 43 Prague 2, Czechia.
| | - Adam Brinek
- CEITEC - Central European Institute of Technology, Brno University of Technology, Czechia
| | - Vladimír Sládek
- Faculty of Science, Charles University, Viničná 7, 128 43 Prague 2, Czechia
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Computer modelling of bone’s adaptation: the role of normal strain, shear strain and fluid flow. Biomech Model Mechanobiol 2016; 16:395-410. [DOI: 10.1007/s10237-016-0824-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/08/2016] [Indexed: 12/17/2022]
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Jindrová A, Tuma J, Sládek V. Impact of Non-Invasively Induced Motor Deficits on Tibial Cortical Properties in Mutant Lurcher Mice. PLoS One 2016; 11:e0158877. [PMID: 27387489 PMCID: PMC4936670 DOI: 10.1371/journal.pone.0158877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/23/2016] [Indexed: 11/18/2022] Open
Abstract
It has been shown that Lurcher mutant mice have significantly altered motor abilities, regarding their motor coordination and muscular strength because of olivorecebellar degeneration. We assessed the response of the cross-sectional geometry and lacuno-canalicular network properties of the tibial mid-diaphyseal cortical bone to motor differences between Lurcher and wild-type (WT) male mice from the B6CBA strain. The first data set used in the cross-sectional geometry analysis consists of 16 mice of 4 months of age and 32 mice of 9 months of age. The second data set used in the lacunar-canalicular network analysis consists of 10 mice of 4 months of age. We compared two cross-sectional geometry and four lacunar-canalicular properties by I-region using the maximum and minimum second moment of area and anatomical orientation as well as H-regions using histological differences within a cross section. We identified inconsistent differences in the studied cross-sectional geometry properties between Lurcher and WT mice. The biggest significant difference between Lurcher and WT mice is found in the number of canaliculi, whereas in the other studied properties are only limited. Lurcher mice exhibit an increased number of canaliculi (p < 0.01) in all studied regions compared with the WT controls. The number of canaliculi is also negatively correlated with the distance from the centroid in the Lurcher and positively correlated in the WT mice. When the Lurcher and WT sample is pooled, the number of canaliculi and lacunar volume is increased in the posterior Imax region, and in addition, midcortical H-region exhibit lower number of canaliculi, lacuna to lacuna distance and increased lacunar volume. Our results indicate, that the importance of precise sample selection within cross sections in future studies is highlighted because of the histological heterogeneity of lacunar-canalicular network properties within the I-region and H-region in the mouse cortical bone.
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Affiliation(s)
- Alena Jindrová
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
- * E-mail:
| | - Jan Tuma
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
- Laboratory of Neurodegenerative Disorders, Biomedical Centre, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Vladimír Sládek
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
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Differences in osteon structure histomorphometry between puppyhood and adult stages in the Golden Retriever. Anat Sci Int 2016; 92:483-492. [PMID: 27084365 DOI: 10.1007/s12565-016-0345-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/03/2016] [Indexed: 10/21/2022]
Abstract
Osteon structure has been widely studied in mammals, but osteon structure in dogs has received relatively little attention, especially in terms of whether aging has any effect on osteon structure. The aim of this study was to compare the osteon structure of both flat (scapula and os coxae) and long bones (humerus, radius, ulna, metacarpus, femur and tibia) of male puppy and adult Golden Retrievers. We examined five parameters: Haversian canal diameter, Haversian canal area, osteon diameter, osteon area, and number of lacunae per osteon. Our results show that the values for Haversian canal diameter were significantly higher in the os coxae and tibia, but significantly lower in the femur of adult dogs as compared to those of puppies. The Haversian canal diameter of the other bones investigated did not show any significant differences between puppies and adult dogs. The Haversian canal area was significantly greater in the os coxae, radius and femur of adult dogs than in those of puppies. The osteon diameter and area of every bone examined were significantly smaller in puppies than in adult dogs. Lastly, the number of lacunae per osteon showed the same trend as osteon diameter and area. Plexiform bone could be found in three bones in puppies, i.e. the femur, humerus and tibia. Overall, the results of this study should provide basic knowledge on the microanatomy of cortical bone in dogs and on the possible influence age.
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Javaheri B, Carriero A, Staines KA, Chang YM, Houston DA, Oldknow KJ, Millan JL, Kazeruni BN, Salmon P, Shefelbine S, Farquharson C, Pitsillides AA. Phospho1 deficiency transiently modifies bone architecture yet produces consistent modification in osteocyte differentiation and vascular porosity with ageing. Bone 2015; 81:277-291. [PMID: 26232374 PMCID: PMC4652607 DOI: 10.1016/j.bone.2015.07.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/24/2015] [Accepted: 07/27/2015] [Indexed: 12/11/2022]
Abstract
PHOSPHO1 is one of principal proteins involved in initiating bone matrix mineralisation. Recent studies have found that Phospho1 KO mice (Phospho1-R74X) display multiple skeletal abnormalities with spontaneous fractures, bowed long bones, osteomalacia and scoliosis. These analyses have however been limited to young mice and it remains unclear whether the role of PHOSPHO1 is conserved in the mature murine skeleton where bone turnover is limited. In this study, we have used ex-vivo computerised tomography to examine the effect of Phospho1 deletion on tibial bone architecture in mice at a range of ages (5, 7, 16 and 34 weeks of age) to establish whether its role is conserved during skeletal growth and maturation. Matrix mineralisation has also been reported to influence terminal osteoblast differentiation into osteocytes and we have also explored whether hypomineralised bones in Phospho1 KO mice exhibit modified osteocyte lacunar and vascular porosity. Our data reveal that Phospho1 deficiency generates age-related defects in trabecular architecture and compromised cortical microarchitecture with greater porosity accompanied by marked alterations in osteocyte shape, significant increases in osteocytic lacuna and vessel number. Our in vitro studies examining the behaviour of osteoblast derived from Phospho1 KO and wild-type mice reveal reduced levels of matrix mineralisation and modified osteocytogenic programming in cells deficient in PHOSPHO1. Together our data suggest that deficiency in PHOSPHO1 exerts modifications in bone architecture that are transient and depend upon age, yet produces consistent modification in lacunar and vascular porosity. It is possible that the inhibitory role of PHOSPHO1 on osteocyte differentiation leads to these age-related changes in bone architecture. It is also intriguing to note that this apparent acceleration in osteocyte differentiation evident in the hypomineralised bones of Phospho1 KO mice suggests an uncoupling of the interplay between osteocytogenesis and biomineralisation. Further studies are required to dissect the molecular processes underlying the regulatory influences exerted by PHOSPHO1 on the skeleton with ageing.
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Affiliation(s)
- B Javaheri
- The Royal Veterinary College, London, United Kingdom.
| | - A Carriero
- Department of Biomedical Engineering, Florida Institute of Technology Melbourne, FL 32901, USA
| | - K A Staines
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Y-M Chang
- The Royal Veterinary College, London, United Kingdom
| | - D A Houston
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - K J Oldknow
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - J L Millan
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | | | - P Salmon
- Bruker-microCT, Kartuizersweg 3B, 2550 Kontich, Belgium
| | - S Shefelbine
- Department of Mechanical and Industrial Engineering, Northeastern University, USA
| | - C Farquharson
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
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D'Emic MD, Benson RBJ. Measurement, variation, and scaling of osteocyte lacunae: a case study in birds. Bone 2013; 57:300-10. [PMID: 23954754 DOI: 10.1016/j.bone.2013.08.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/16/2013] [Accepted: 08/11/2013] [Indexed: 11/19/2022]
Abstract
Basic issues surrounding osteocyte biology are still poorly understood, including the variability of osteocyte morphology within and among bones, individuals, and species. Several studies have suggested that the volume or shape of osteocytes (or their lacunae) is related to bone and/or organismal growth rate or metabolism, but the nature of this relationship, if any, is unclear. Furthermore, several studies have linked osteocyte lacuna volume with genome size or growth rate and suggested that osteocyte lacuna volume is unrelated to body size. Herein the scaling of osteocyte lacuna volume with body mass, growth and basal metabolic rates, genome size, and red blood cell size is examined using a broad sample of extant birds within a phylogenetic framework. Over 12,000 osteocyte lacuna axes were measured in a variety of bones from 34 avian and four non-avian dinosaur species. Osteocyte lacunae in parallel-fibered bone are scalene ellipsoids; their morphology and volume cannot be reliably estimated from any single thin section, and using a prolate ellipsoid model to estimate osteocyte lacuna volume results in a substantial (ca. 2-7 times) underestimate relative to true lacunar volume. Orthogonal thin sections reveal that in birds, even when only observing parallel-fibered, primary, cortical bone, intra-skeletal variation in osteocyte lacuna volume and shape is very high (volumes vary by a factor of 5.4 among different bones), whereas variation among homologous bones of the same species is low (1.2-44%; mean=12%). Ordinary and phylogenetically informed bivariate and multiple regressions demonstrate that in birds, osteocyte volume scales significantly but weakly with body mass and mass-specific basal metabolic rate and moderately with genome size, but not with erythrocyte size. Avian whole-body growth rate and osteocyte lacuna volume are weakly and inversely related. Finally, we present the first three-dimensionally calculated osteocyte volumes for several non-avian dinosaurs, which are much larger than previously reported values and smaller than those of large extant avians. Osteocyte volumes estimated from a single transverse section and assuming prolate morphology, as done in previous studies, are relative underestimates in theropod dinosaurs compared to sauropod dinosaurs, raising the possibility that no major change in osteocyte volumes (and genome size) occurred within Theropoda on the lineage leading to birds. Osteocyte volume is intertwined with several organismal attributes whose relative importance varies at a number of hierarchical levels.
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Affiliation(s)
- Michael D D'Emic
- Anatomical Sciences Department, Stony Brook University, Stony Brook, NY 11794, USA.
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Stein KWH, Werner J. Preliminary analysis of osteocyte lacunar density in long bones of tetrapods: all measures are bigger in sauropod dinosaurs. PLoS One 2013; 8:e77109. [PMID: 24204748 PMCID: PMC3812986 DOI: 10.1371/journal.pone.0077109] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 09/03/2013] [Indexed: 02/04/2023] Open
Abstract
Osteocytes harbour much potential for paleobiological studies. Synchrotron radiation and spectroscopic analyses are providing fascinating data on osteocyte density, size and orientation in fossil taxa. However, such studies may be costly and time consuming. Here we describe an uncomplicated and inexpensive method to measure osteocyte lacunar densities in bone thin sections. We report on cell lacunar densities in the long bones of various extant and extinct tetrapods, with a focus on sauropodomorph dinosaurs, and how lacunar densities can help us understand bone formation rates in the iconic sauropod dinosaurs. Ordinary least square and phylogenetic generalized least square regressions suggest that sauropodomorphs have lacunar densities higher than scaled up or comparably sized mammals. We also found normal mammalian-like osteocyte densities for the extinct bovid Myotragus, questioning its crocodilian-like physiology. When accounting for body mass effects and phylogeny, growth rates are a main factor determining the density of the lacunocanalicular network. However, functional aspects most likely play an important role as well. Observed differences in cell strategies between mammals and dinosaurs likely illustrate the convergent nature of fast growing bone tissues in these groups.
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Affiliation(s)
- Koen W. H. Stein
- Steinmann Institut für Geologie, Mineralogie und Paläontologie, University of Bonn, Bonn, Germany
| | - Jan Werner
- Institut für Zoologie, Abteilung Ökologie, Johannes Gutenberg-Universität Mainz, Mainz, Germany
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Stein K, Prondvai E. Rethinking the nature of fibrolamellar bone: an integrative biological revision of sauropod plexiform bone formation. Biol Rev Camb Philos Soc 2013; 89:24-47. [DOI: 10.1111/brv.12041] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 03/20/2013] [Accepted: 04/03/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Koen Stein
- Steinmann Institut für Geologie, Mineralogie und Paläontologie; University of Bonn; Bonn Germany
| | - Edina Prondvai
- Hungarian Academy of Sciences-Eötvös Loránd University “Lendület” Dinosaur Research Group; Eötvös Loránd University; Budapest Hungary
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Jast J, Jasiuk I. Age-related changes in the 3D hierarchical structure of rat tibia cortical bone characterized by high-resolution micro-CT. J Appl Physiol (1985) 2013; 114:923-33. [PMID: 23329820 DOI: 10.1152/japplphysiol.00948.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Three-dimensional hierarchical structure of female Sprague-Dawley rat tibia cortical bone was characterized as a function of age (3, 12, 32, 42, 60, and 72 wk) using a high-resolution micro-computed tomography. At the whole bone level, 3-wk samples exhibited statistically significant differences in a mean total tissue volume, mean cortical bone volume, mean cortical bone volume density, mean periosteal perimeter, and mean cortical thickness (P < 0.05) compared with all other ages. At the tissue level, there was a statistically significant increase in a mean canal number density and a decrease in a mean canal volume and diameter between 3-wk and 12-wk samples. While no significant variations were found between mean canal lengths, there was a dependence of mean canal orientation on age. At the cell level, there were no statistically significant differences in a lacuna number density and a lacuna volume density, and all lacunae element-based parameters displayed no dependence on age across age. In addition, at the microstructural level, the cannular indexes were reported separately for anterior, posterior, medial, and lateral anatomic regions. From 3 to 32 wk of age, there existed significantly fewer canals per volume of bone in the medial region of the tibia vs. other cross-sectional quadrants. Although there were changes with age, there were no statistically significant differences in the mean canal volume, mean canal diameter, and mean canal length between the four anatomic regions.
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Affiliation(s)
- John Jast
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61822, USA
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Carter Y, Thomas CDL, Clement JG, Peele AG, Hannah K, Cooper DML. Variation in osteocyte lacunar morphology and density in the human femur--a synchrotron radiation micro-CT study. Bone 2013; 52:126-32. [PMID: 22995461 DOI: 10.1016/j.bone.2012.09.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 08/30/2012] [Accepted: 09/06/2012] [Indexed: 11/29/2022]
Abstract
In recent years there has been growing interest in the spatial properties of osteocytes (including density and morphology) and how these potentially relate to adaptation, disease and aging. This interest has, in part, arisen from the availability of increasingly high-resolution 3D imaging modalities such as synchrotron radiation (SR) micro-CT. As resolution increases, field of view generally decreases. Thus, while increasingly detailed spatial information is obtained, it is unclear how representative this information is of the skeleton or even the isolated bone. The purpose of this research was to describe the variation in osteocyte lacunar density, morphology and orientation within the femur from a healthy young male human. Multiple anterior, posterior, medial and lateral blocks (2 mm × 2 mm) were prepared from the proximal femoral shaft and SR micro-CT imaged at the Advanced Photon Source. Average lacunar densities (± standard deviation) from the anterior, posterior, medial and lateral regions were 27,169 ± 1935, 26,3643 ± 1262, 37,521 ± 6416 and 33,972 ± 2513 lacunae per mm(3) of bone tissue, respectively. These values were significantly different between the medial and both the anterior and posterior regions (p<0.05). The density of the combined anterior and posterior regions was also significantly lower (p=0.001) than the density of the combined medial and lateral regions. Although no difference was found in predominant orientation, shape differences were found; with the combined anterior and posterior regions having more elongated (p=0.004) and flattened (p=0.045) lacunae, than those of the medial and lateral regions. This study reveals variation in osteocyte lacunar density and morphology within the cross-section of a single bone and that this variation can be considerable (up to 30% difference in density between regions). The underlying functional significance of the observed variation in lacunar density likely relates to localized variations in loading conditions as the pattern corresponds well with mechanical axes. Lower density and more elongate shapes being associated with the antero-posterior oriented neutral axis. Our findings demonstrate that the functional and pathological interpretations that are increasingly being drawn from high resolution imaging of osteocyte lacunae need to be better situated within the broader context of normal variation, including that which occurs even within a single skeletal element.
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Affiliation(s)
- Yasmin Carter
- Department of Anatomy & Cell Biology, University of Saskatchewan, Saskatoon, Canada.
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Dominguez VM, Crowder CM. The utility of osteon shape and circularity for differentiating human and non-human Haversian bone. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2012; 149:84-91. [PMID: 22700390 DOI: 10.1002/ajpa.22097] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 04/24/2012] [Indexed: 11/11/2022]
Abstract
Distinguishing human from non-human bone fragments is usually accomplished by observation of gross morphology. When macroscopic analysis is insufficient, histological approaches can be applied. Microscopic features, like plexiform bone or osteon banding, are characteristic of non-humans. In the absence of such features, distinguishing Haversian bone as either human or non-human proves problematic. This study proposes a histomorphometric approach for classifying species from Haversian bone. Two variables, osteon area (On.Ar.) and circularity (On.Cr.), are examined. Measurements were collected from three species (deer, dog, human) represented by various skeletal elements; only ribs were available for humans (ribs: deer n = 6, dog n = 6, human n = 26; humeri: deer n = 6, dog n = 6; femora: deer n = 6, dog n = 6). Qualitative analysis comparing human to non-human On.Ar. demonstrated that human ribs have larger mean On.Ar. (0.036 mm(2)) than non-human ribs (deer = 0.017 mm(2) , dog = 0.013 mm(2)). On.Cr. in the ribs showed minor differences between species (deer = 0.877; dog = 0.885; human = 0.898). Results demonstrated no significant difference across long bone quadrants in long bones. Discriminant analyses run on the means for each sample demonstrated overlap in deer and dog samples, clustering the non-human and human groups apart from each other. Mean On.Cr. proved a poor criterion (ribs only: 76.3%, pooled elements: 66.1%), while mean On.Ar. proved useful in identifying human from non-human samples (ribs only: 92.1%, pooled elements: 93.5%). When variables were combined, accuracy increased to 100% correct classification for rib data and 98.4% when considering data from all elements. These results indicate that On.Ar. and On.Cr. are valuable histomorphometric tools for distinguishing human from non-human Haversian bone.
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Ambekar R, Chittenden M, Jasiuk I, Toussaint KC. Quantitative second-harmonic generation microscopy for imaging porcine cortical bone: comparison to SEM and its potential to investigate age-related changes. Bone 2012; 50:643-50. [PMID: 22155019 DOI: 10.1016/j.bone.2011.11.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 11/09/2011] [Accepted: 11/21/2011] [Indexed: 11/24/2022]
Abstract
We propose the use of second-harmonic generation (SHG) microscopy for imaging collagen fibers in porcine femoral cortical bone. The technique is compared with scanning electron microscopy (SEM). SHG microscopy is shown to have excellent potential for bone imaging primarily due its intrinsic specificity to collagen fibers, which results in high contrast images without the need for specimen staining. Furthermore, this technique's ability to quantitatively assess collagen fiber organization is evaluated through an exploratory examination of bone structure as a function of age, from very young to mature bone. In particular, four different age groups: 1 month, 3.5 months, 6 months, and 30 months, were studied. Specifically, we employ the recently developed Fourier transform-second harmonic generation (FT-SHG) imaging technique for the quantification of the structural changes, and observe that as the bone develops, there is an overall reduction in porosity, the number of osteons increases, and the collagen fibers become comparatively more organized. It is also observed that the variations in structure across the whole cross-section of the bone increase with age. The results of this work show that quantitative SHG microscopy can serve as a valuable tool for evaluating the structural organization of collagen fibers in ex vivo bone studies.
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Affiliation(s)
- Raghu Ambekar
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, IL 61801, USA
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Simons EL, O'connor PM. Bone Laminarity in the Avian Forelimb Skeleton and Its Relationship to Flight Mode: Testing Functional Interpretations. Anat Rec (Hoboken) 2012; 295:386-96. [DOI: 10.1002/ar.22402] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 11/26/2011] [Indexed: 11/11/2022]
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Sugawara Y, Ando R, Kamioka H, Ishihara Y, Honjo T, Kawanabe N, Kurosaka H, Takano-Yamamoto T, Yamashiro T. The three-dimensional morphometry and cell-cell communication of the osteocyte network in chick and mouse embryonic calvaria. Calcif Tissue Int 2011; 88:416-24. [PMID: 21340572 DOI: 10.1007/s00223-011-9471-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 01/25/2011] [Indexed: 12/22/2022]
Abstract
The study of osteocytes has progressed in chicks. We examined whether chick osteocyte data can be applied to other species. We used mice for comparison because they are common clinical tools in biomedical research and useful for future study. We analyzed the three-dimensional (3D) osteocyte network and gap junctional intercellular communication (GJIC) in living embryonic calvaria for the anatomical features. Embryonic parietal bones were stained with fluorescently labeled phalloidin and observed using confocal laser scanning microscopy. GJIC between osteocytes in chick and mouse parietal bone was assessed using fluorescence recovery after photobleaching (FRAP). The values for one chick and mouse osteocyte, respectively, were calculated as follows: cell processes 1,131 ± 139 μm, 2,668 ± 596 μm; surface area 1,128 ± 358 μm(2), 2,654 ± 659 μm(2); and cell volume 455 ± 90 μm(3), 1,328 ± 210 μm(3). The density of 3D osteocyte processes in the bone matrix was not significantly different. FRAP analysis showed dye coupling among osteocytes in chick and mouse bone. The fluorescence intensity recovered to 49.0 ± 2.4% in chicks and 39.9 ± 2.4% in mice after 5 minutes. Fluorescence recovery was similar within 4 minutes. The difference in osteocyte size between the two species might have affected their functions. Osteocyte processes in the two species may sense similarly changes in the exterior environment. We successfully conducted morphological and functional analyses of the osteocyte network in chicks and mice. The size of the osteocytes in bone differed between the two species.
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Affiliation(s)
- Yasuyo Sugawara
- Department of Orthodontics and Dentofacial Orthopedics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata, Okayama-City, Okayama 700-8525, Japan.
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Matsumoto T, Ando N, Tomii T, Uesugi K. Three-dimensional cortical bone microstructure in a rat model of hypoxia-induced growth retardation. Calcif Tissue Int 2011; 88:54-62. [PMID: 20848090 DOI: 10.1007/s00223-010-9415-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 08/31/2010] [Indexed: 12/20/2022]
Abstract
Little is known about hypoxia-induced modification of the canal network in the cortical bone despite its involvement in intracortical vascularity and bone blood supply. In this study, we examined the effect of chronic hypoxia on the canal network in postnatal bone. Tibiae were harvested from 4- and 8-week-old rats (hyp-4 and -8, n = 8 each), whose growth was retarded owing to postnatal exposure to hypoxia (12-14% O₂), and from 3- and 4-week-old normoxic rats (cnt-4 and -5, n = 8 each), which were similar in tibial length and cortical cross-sectional area to hyp-4 and -8, respectively. The diaphyseal canals were detected by monochromatic synchrotron radiation CT with a 3.1-μm voxel resolution. The anatomical properties of the canal network were compared between age- or size-matched hypoxic and normoxic groups. The canals were larger in diameter, were more densely distributed and connected, and opened into the marrow cavity with a higher density in hyp-4 than in cnt-4. The canal density and connectivity were also higher in hyp-4 than in cnt-3. The canal diameter, density, and connectivity were smaller in hyp-8 than in cnt-4; however, the densities of endocortical and periosteal canal openings did not differ between hyp-8 and cnt-4. We concluded that chronic hypoxia enhanced the formation of cortical canal networks at the postnatal developmental stage, probably facilitating intra- and transcortical vascularization and bone perfusion accordingly.
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Affiliation(s)
- Takeshi Matsumoto
- Bioengineering Division, Osaka University Graduate School of Engineering Science, Machikaneyama-cho 1-3, Toyonaka 560-8531, Japan.
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Kwon RY, Meays DR, Tang WJ, Frangos JA. Microfluidic enhancement of intramedullary pressure increases interstitial fluid flow and inhibits bone loss in hindlimb suspended mice. J Bone Miner Res 2010; 25:1798-807. [PMID: 20200992 PMCID: PMC3153350 DOI: 10.1002/jbmr.74] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Interstitial fluid flow (IFF) has been widely hypothesized to mediate skeletal adaptation to mechanical loading. Although a large body of in vitro evidence has demonstrated that fluid flow stimulates osteogenic and antiresorptive responses in bone cells, there is much less in vivo evidence that IFF mediates loading-induced skeletal adaptation. This is due in large part to the challenges associated with decoupling IFF from matrix strain. In this study we describe a novel microfluidic system for generating dynamic intramedullary pressure (ImP) and IFF within the femurs of alert mice. By quantifying fluorescence recovery after photobleaching (FRAP) within individual lacunae, we show that microfluidic generation of dynamic ImP significantly increases IFF within the lacunocanalicular system. In addition, we demonstrate that dynamic pressure loading of the intramedullary compartment for 3 minutes per day significantly eliminates losses in trabecular and cortical bone mineral density in hindlimb suspended mice, enhances trabecular and cortical structural integrity, and increases endosteal bone formation rate. Unlike previously developed modalities for enhancing IFF in vivo, this is the first model that allows direct and dynamic modulation of ImP and skeletal IFF within mice. Given the large number of genetic tools for manipulating the mouse genome, this model is expected to serve as a powerful investigative tool in elucidating the role of IFF in skeletal adaptation to mechanical loading and molecular mechanisms mediating this process.
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Affiliation(s)
- Ronald Y Kwon
- La Jolla Bioengineering Institute, La Jolla, CA, USA
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The effect of two clinically relevant fusionless scoliosis implant strategies on the health of the intervertebral disc: analysis in an immature goat model. Spine (Phila Pa 1976) 2010; 35:371-7. [PMID: 20110838 DOI: 10.1097/brs.0b013e3181b962a4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Immature goat spines were instrumented at 5 levels with 2 different fusionless scoliosis implants. Instrumented and subadjacent spinal segments were analyzed to determine the effect on the disc and endplate. OBJECTIVE Analyze the regional biochemistry and histology of spinal motion segments in healthy goat spines treated with 2 clinically relevant, fusionless scoliosis implants. SUMMARY OF BACKGROUND DATA Fusionless scoliosis surgery is thought to be more physiologic than fusion as it preserves the growth, motion, and function of the spine. There are presently little data supporting this belief. METHODS Scoliosis was created in twelve 8-week-old female goats (n = 6 per group) using 1 of 2 fusionless scoliosis implant strategies: 2 SMA staples per level or a bone anchor/ligament tether. A third group served as controls (n = 6). Goats were analyzed after 6 months. Qualitative and quantitative analyses were performed on spinal motion segments using H&E, TUNEL, and caspase-3 staining. RESULTS Neither implant strategy produced degenerative changes in the disc. However, discs at instrumented levels in both groups demonstrated decreased cell density (P < 0.01) and increased cellular apoptosis (P < 0.001) compared to controls. Subadjacent discs demonstrated preservation of viable cells and endplate vascularity compared to instrumented discs. CONCLUSION Fusionless scoliosis implants result in alterations in viable cell density within the disc and reduced vascularity in the vertebral endplates of instrumented but not subadjacent discs. Though obvious disc degeneration was not observed, the implications of the cellular and histologic changes are not known. Additional study will be necessary to better understand various fusionless scoliosis surgery strategies and their effect on surrounding tissues.
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Poliachik SL, Threet D, Srinivasan S, Gross TS. 32 wk old C3H/HeJ mice actively respond to mechanical loading. Bone 2008; 42:653-9. [PMID: 18280231 PMCID: PMC2366046 DOI: 10.1016/j.bone.2007.12.222] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 12/19/2007] [Accepted: 12/27/2007] [Indexed: 10/22/2022]
Abstract
Numerous studies indicate that C3H/HeJ (C3H) mice are mildly responsive to mechanical loading compared to C57BL/6J (C57) mice. Guided by data indicating high baseline periosteal osteoblast activity in 16 wk C3H mice, we speculated that simply allowing the C3H mice to age until basal periosteal bone formation was equivalent to that of 16 wk C57 mice would restore mechanoresponsiveness in C3H mice. We tested this hypothesis by subjecting the right tibiae of 32 wk old C3H mice and 16 wk old C57 mice to low magnitude rest-inserted loading (peak strain: 1235 mu epsilon) and then exposing the right tibiae of 32 wk C3H mice to low (1085 mu epsilon) or moderate (1875 mu epsilon) magnitude cyclic loading. The osteoblastic response to loading on the endocortical and periosteal surfaces was evaluated via dynamic histomorphometry. At 32 wk of age, C3H mice responded to low magnitude rest-inserted loading with significantly elevated periosteal mineralizing surface, mineral apposition rate and bone formation compared to unloaded contralateral bones. Surprisingly, the periosteal bone formation induced by low magnitude rest-inserted loading in C3H mice exceeded that induced in 16 wk C57 mice. At 32 wk of age, C3H mice also demonstrated an elevated response to increased magnitudes of cyclic loading. We conclude that a high level of basal osteoblast function in 16 wk C3H mice appears to overwhelm the ability of the tissue to respond to an otherwise anabolic mechanical loading stimulus. However, when basal surface osteoblast activity is equivalent to that of 16 wk C57 mice, C3H mice demonstrate a clear ability to respond to either rest-inserted or cyclic loading.
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Affiliation(s)
- Sandra L Poliachik
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, 98104, USA.
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Schneider P, Stauber M, Voide R, Stampanoni M, Donahue LR, Müller R. Ultrastructural properties in cortical bone vary greatly in two inbred strains of mice as assessed by synchrotron light based micro- and nano-CT. J Bone Miner Res 2007; 22:1557-70. [PMID: 17605631 DOI: 10.1359/jbmr.070703] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED Nondestructive SR-based microCT and nano-CT methods have been designed for 3D quantification and morphometric analysis of ultrastructural phenotypes within murine cortical bone, namely the canal network and the osteocyte lacunar system. Results in two different mouse strains, C57BL/6J-Ghrhr(lit)/J and C3.B6-Ghrhr(lit)/J, showed that the cannular and lacunar morphometry and their bone mechanics were fundamentally different. INTRODUCTION To describe the different aspects of bone quality, we followed a hierarchical approach and assessed bone tissue properties in different regimens of spatial resolution, beginning at the organ level and going down to cellular dimensions. For these purposes, we developed different synchrotron radiation (SR)-based CT methods to assess ultrastructural phenotypes of murine bone. MATERIALS AND METHODS The femoral mid-diaphyses of 12 C57BL/6J-Ghrhr(lit)/J (B6-lit/lit) and 12 homozygous mutants C3.B6-Ghrhr(lit)/J (C3.B6-lit/lit) were measured with global SR microCT and local SR nano-CT (nCT) at nominal resolutions ranging from 3.5 microm to 700 nm, respectively. For volumetric quantification, morphometric indices were determined for the cortical bone, the canal network, and the osteocyte lacunar system using negative imaging. Moreover, the biomechanics of B6-lit/lit and C3.B6-lit/lit mice was determined by three-point bending. RESULTS The femoral mid-diaphysis of C3.B6-lit/lit was larger compared with B6-lit/lit mice. On an ultrastructural level, the cannular indices for C3.B6-lit/lit were generally bigger in comparison with B6-lit/lit mice. Accordingly, we derived and showed a scaling rule, saying that overall cannular indices scaled with bone size, whereas indices describing basic elements of cannular and lacunar morphometry did not. Although in C3.B6-lit/lit, the mean canal volume was larger than in B6-lit/lit, canal number density was proportionally smaller in C3.B6-lit/lit, so that lacuna volume density was found to be constant and therefore independent of mouse strain and sex. The mechanical properties in C3.B6-lit/lit were generally improved compared with B6-lit/lit specimens. For C3.B6-lit/lit, we observed a sex specificity of the mechanical parameters, which could not be explained by bone morphometry on an organ level. However, there is evidence that for C3.B6-lit/lit, the larger cortical bone mass is counterbalanced or even outweighed by the larger canal network in the female mice. CONCLUSIONS We established a strategy to subdivide murine intracortical porosity into ultrastructural phenotypes, namely the canal network and the osteocyte lacunar system. Nondestructive global and local SR-based CT methods have been designed for 3D quantification and subsequent morphometric analysis of these phenotypes. Results in the two different mouse strains C57BL/6J-Ghrhr(lit)/J and C3.B6-Ghrhr(lit)/J showed that the cannular and lacunar morphometry and the biomechanical properties were fundamentally different.
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Affiliation(s)
- Philipp Schneider
- Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland
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Main RP. Ontogenetic relationships between in vivo strain environment, bone histomorphometry and growth in the goat radius. J Anat 2007; 210:272-93. [PMID: 17331177 PMCID: PMC2100276 DOI: 10.1111/j.1469-7580.2007.00696.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Vertebrate long bone form, at both the gross and the microstructural level, is the result of many interrelated influences. One factor that is considered to have a significant effect on bone form is the mechanical environment experienced by the bone during growth. The work presented here examines the possible relationships between in vivo bone strains, bone geometry and histomorphology in the radii of three age/size groups of domestic goats. In vivo bone strain data were collected from the radii of galloping goats, and the regional cortical distribution of peak axial strain magnitudes, radial and circumferential strain gradients, and longitudinal strain rates related to regional patterns in cortical growth, porosity, remodelling and collagen fibre orientation. Although porosity and remodelling decreased and increased with age, respectively, these features showed no significant regional differences and did not correspond to regional patterns in the mechanical environment. Thicker regions of the radius's cortex were significantly related to high strain levels and higher rates of periosteal, but not endosteal, growth. However, cortical growth and strain environment were not significantly related. Collagen fibre orientation varied regionally, with a higher percentage of transverse fibres in the caudal region of the radius and primarily longitudinal fibres elsewhere, and, although consistent through growth, also did not generally correspond to regional strain patterns. Although strain magnitudes increased during ontogeny and regional strain patterns were variable over the course of a stride, mean regional strain patterns were generally consistent with growth, suggesting that regional growth patterns and histomorphology, in combination with external loads, may play some role in producing a relatively 'predictable' strain environment within the radius. It is further hypothesized that the absence of correlation between regional histomorphometric patterns and the measured strain environments is the result of the variable mechanical environment. However, the potential effects of other physiological and mechanical factors, such as skeletal metabolism and adjacent muscle insertions, that can influence the gross and microstructural morphology of the radius during ontogeny, cannot be ignored.
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Affiliation(s)
- Russell P Main
- Concord Field Station, Department of Organismic and Evolutionary Biology, Harvard University, Bedford, MA 01730, USA.
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Carlson KJ, Patel BA. Habitual use of the primate forelimb is reflected in the material properties of subchondral bone in the distal radius. J Anat 2006; 208:659-70. [PMID: 16761969 PMCID: PMC2100237 DOI: 10.1111/j.1469-7580.2006.00555.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2006] [Indexed: 11/30/2022] Open
Abstract
Bone mineral density is directly proportional to compressive strength, which affords an opportunity to estimate in vivo joint load history from the subchondral cortical plate of articular surfaces in isolated skeletal elements. Subchondral bone experiencing greater compressive loads should be of relatively greater density than subchondral bone experiencing less compressive loading. Distribution of the densest areas, either concentrated or diffuse, also may be influenced by the extent of habitual compressive loading. We evaluated subchondral bone in the distal radius of several primates whose locomotion could be characterized in one of three general ways (quadrupedal, suspensory or bipedal), each exemplifying a different manner of habitual forelimb loading (i.e. compression, tension or non-weight-bearing, respectively). We employed computed tomography osteoabsorptiometry (CT-OAM) to acquire optical densities from which false-colour maps were constructed. The false-colour maps were used to evaluate patterns in subchondral density (i.e. apparent density). Suspensory apes and bipedal humans had both smaller percentage areas and less well-defined concentrations of regions of high apparent density relative to quadrupedal primates. Quadrupedal primates exhibited a positive allometric effect of articular surface size on high-density area, whereas suspensory primates exhibited an isometric effect and bipedal humans exhibited no significant relationship between the two. A significant difference between groups characterized by predominantly compressive forelimb loading regimes vs. tensile or non-weight-bearing regimes indicates that subchondral apparent density in the distal radial articular surface distinguishes modes of habitually supporting of body mass.
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Affiliation(s)
- Kristian J Carlson
- Department of Anatomical Sciences, School of Medicine, Stony Brook University, USA.
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Skedros JG. Osteocyte Lacuna Population Densities in Sheep, Elk and Horse Calcanei. Cells Tissues Organs 2006; 181:23-37. [PMID: 16439816 DOI: 10.1159/000089966] [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] [Accepted: 08/18/2005] [Indexed: 11/19/2022] Open
Abstract
Osteocytes, the most prevalent cell type in bone, appear to communicate via gap junctions. In limb-bone diaphyses, it has been hypothesized that these cellular networks have the capacity to monitor habitual strains, which can differ significantly between cortical locations of the same bone. Regional differences in microdamage associated with prevalent/predominant strain mode (tension, compression, or shear) and/or magnitude may represent an important "variable" detected by this network. This hypothesis was indirectly addressed by examining bones subjected to habitual bending for correlations of osteocyte lacuna population densities (n/mm(2) bone area, Ot.Lc.N/B.Ar) with locations experiencing high and low strain, and/or prevalent/predominant tension, compression, and shear. We examined dorsal ("compression"), plantar ("tension"), and medial/lateral ("shear" or neutral axis) cortices of mid-diaphyseal sections of calcanei of adult sheep, elk, and horses. Ot.Lc.N/B.Ar data, quantified in backscattered electron images, were also evaluated in a context of various additional structural and material variables (e.g. % ash, cortical thickness, porosity, and secondary osteon population). Results showed significant differences in dorsal versus plantar comparisons with the highest Ot.Lc.N/B.Ar in dorsal cortices of sheep and elk (p < 0.0001); but this was a statistical trend in the equine calcanei (p = 0.14). There were no consistent transcortical (pericortical to endocortical) differences, and Ot.Lc.N/B.Ar in neutral axes was not consistently different from dorsal/plantar cortices. Correlations of Ot.Lc.N/B.Ar with structural and material parameters were also poor and/or inconsistent within or between species. These results provide little or no evidence that the number of osteocyte lacunae has a functional role in mechanotransduction pathways that are typically considered in bone adaptation. Although dorsal/plantar differences may be adaptations for prevalent/predominant strain modes and/or associated microdamage, it is also plausible that they are strongly influenced by differences in the bone formation rates that produced the tissue in these locations.
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Affiliation(s)
- John G Skedros
- Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT 84107, USA.
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Abstract
Muscular reconstructions in vertebrate paleontology have often relied heavily on the presence of "muscle scars" and similar osteological correlates of muscle attachment, a practice complicated by the fact that approximately half of tendinous muscle attachments to bone in extant vertebrates do not leave readily interpretable scars. Microanatomical and histological correlates of tendinous muscle attachment are much less ambiguous. This study examines the microanatomical correlates of muscle attachment for the mandibular adductors in six species of diapsids. Most prominent tendinous or aponeurotic muscle attachments display a high density of extrinsic fibers (similar to Sharpey's fibers). There is also some indication that the density of extrinsic fibers at an attachment may be directly related to the amount of stress exerted on that attachment. The presence of comparable densities of extrinsic fibers in fossil tissue constitutes strong and readily interpretable positive evidence for the presence of adjacent fibrous connective tissue in life. Microanatomy and histology provide reliable data about muscle attachments that cannot be gleaned from gross observation alone. These additional data, when coupled with existing muscular reconstruction techniques, may be essential to the resolution of ambiguous character states, and will provide more severe tests for long-standing hypotheses of musculature in extinct diapsids. Increasing the accuracy and precision of muscular reconstructions lends greater strength to any phylogenetic, paleobiological, or paleoecological inferences that draw upon these reconstructions as important lines of evidence.
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de Margerie E, Sanchez S, Cubo J, Castanet J. Torsional resistance as a principal component of the structural design of long bones: comparative multivariate evidence in birds. ACTA ACUST UNITED AC 2005; 282:49-66. [PMID: 15584036 DOI: 10.1002/ar.a.20141] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Here we study the occurrence of torsion-resisting morphological and histological features (thin bone walls, circular shaft cross-section, oblique collagen fibers, and laminar tissue arrangement) in a sample of 168 long bones from wings and legs of 22 bird species. These structural parameters were measured in mid diaphyseal undemineralized cross-sections and analyzed using uni-, bi-, and multivariate (principal components analysis) data analysis techniques. We found that the four variables are significantly and positively correlated, and that covariation between variables accounts for as much as 58% of the total variation. These results suggest that torsion is a main determinant of the macro- and microstructural design of long bones in birds. Humerus, ulna, and femur generally possess torsion-resisting features, while other bones (radius, carpometacarpus, tibiotarsus, tarsometatarsus, and foot phalanx) rather show bending/axial load-resisting structural properties. These results are congruent with in vivo strain data from the literature, which reported high torsional loading in humerus and ulna during flapping flight, but also in the subhorizontal avian femur during terrestrial locomotion. The precise function of the laminar tissue spatial arrangement, the role of pneumatization, and the influence of flight mode are discussed.
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Affiliation(s)
- Emmanuel de Margerie
- Comparative Osteohistology, FRE CNRS 2696, Université Paris 6-7, Case 7077, Place Jussieu, 75005 Paris, France.
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Skedros JG, Grunander TR, Hamrick MW. Spatial Distribution of Osteocyte Lacunae in Equine Radii and Third Metacarpals: Considerations for Cellular Communication, Microdamage Detection and Metabolism. Cells Tissues Organs 2005; 180:215-36. [PMID: 16330878 DOI: 10.1159/000088938] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2005] [Indexed: 11/19/2022] Open
Abstract
Osteocytes, which are embedded in bone matrix, are the most abundant cells in bone. Despite the ideal location of osteocytes to sense the local environment and influence bone remodeling, their functions, and the relative importance of these functions, remain controversial. In this study, we tested several hypotheses that address the possibilities that population densities of osteocyte lacunae (Ot.Lc.N/B.Ar) correlate with strain-, remodeling- or metabolism-related aspects of the local biomechanical environments of mid-third diaphyseal equine radii and third metacarpals from skeletally mature animals. Ot.Lc.N/B.Ar data, quantified in multiple cortical locations, were analyzed for possible correlations with (1) structural and material characteristics (e.g., cortical thickness, percent ash, secondary osteon population density, mean osteon cross-sectional area, and predominant collagen fiber orientation), (2) strain characteristics, including prevalent/predominant strain magnitude and mode (tension, compression, shear), (3) hypothesized strain-mode-related microdamage characteristics, which might be perceived by osteocyte 'operational' networks, and (4) variations in remodeling dynamics and/or metabolism (i.e. presumably higher in endocortical regions than in other transcortical locations). Results showed relatively uniform Ot.Lc.N/B.Ar between regions with highly non-uniform strain and strain-related environments and markedly heterogeneous structural and material organization. These results suggest that population densities of these cells are poorly correlated with mechanobiological characteristics, including local variations in metabolic rate and strain magnitude/mode. Although osteocytes hypothetically evolved both as strain sensors and fatigue damage sensors able to direct the removal of damage as needed, the mechanisms that govern the distribution of these cells remain unclear. The results of this study provide little or no evidence that the number of osteocyte lacunae has a functional role in mechanotransduction pathways that are typically considered in bone adaptation.
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Affiliation(s)
- John G Skedros
- Department of Orthopaedic Surgery, University of Utah, Salt Lake City, USA.
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Skedros JG, Hunt KJ. Does the degree of laminarity correlate with site-specific differences in collagen fibre orientation in primary bone? An evaluation in the turkey ulna diaphysis. J Anat 2004; 205:121-34. [PMID: 15291795 PMCID: PMC1571335 DOI: 10.1111/j.0021-8782.2004.00318.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
de Margerie hypothesized that preferred orientations of primary vascular canals in avian primary cortical bone mediate important mechanical adaptations. Specifically, bones that receive habitual compression, tension or bending stresses typically have cortices with a low laminarity index (LI) (i.e. relatively lower cross-sectional areas of circularly (C) orientated primary vascular canals, and relatively higher areas of canals with radial (R), oblique (O) or longitudinal (L) orientations. By contrast, bones subject to habitual torsion have a high LI (i.e. relatively higher C-orientated canal area) [LI, based on percentage vascular canal area, = C/(C + R + O + L)]. Regional variations in predominant collagen fibre orientation (CFO) may be the adaptive characteristic mediated by LI. Using turkey ulnae, we tested the hypothesis that site-specific variations in predominant CFO and LI are strongly correlated. Mid-diaphyseal cross-sections (100 +/- 5 micro m) from subadult and adult bones were evaluated for CFO and LI using circularly polarized light images of cortical octants. Results showing significant differences between mean LI of subadult (40.0% +/- 10.7%) and adult (50.9% +/- 10.4%) (P < 0.01) bones suggest that adult bones experience more prevalent/predominant torsion. Alternatively, this relationship may reflect differences in growth rates. High positive correlations between LI and predominant CFO (subadults: r = 0.735; adults: r = 0.866; P < 0.001) suggest that primary bone can exhibit potentially adaptive material variations that are independent of secondary osteon formation.
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Affiliation(s)
- John G Skedros
- Bone and Joint Research Laboratory, Veteran's Affairs Medical Center, Salt Lake City, Utah 84107, USA.
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Lee AH. Histological organization and its relationship to function in the femur of Alligator mississippiensis. J Anat 2004; 204:197-207. [PMID: 15032909 PMCID: PMC1571257 DOI: 10.1111/j.0021-8782.2004.00275.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Histological analysis of a growth series of alligator femora tests the correlation between strain milieu and microstructure. From mid-diaphyseal cross-sections of these femora (n = 7), vascular canal orientation and density as well as collagen fibre organization were recorded. Throughout ontogeny, the proportion of transverse-spiral (TS) collagen in the dorsal cortex is significantly greater than it is in the ventral cortex (P = 0.008). This regional difference in the proportion of TS collagen is correlated with a regional difference in the state of peak principal strain (compressive or tensile). Nevertheless, the predominant orientation of collagen fibres is longitudinal, which is inconsistent with biomechanical hypotheses that involve peak principal or shear strains. Although the density and orientation of vascular canals do not show significant regional differences (P = 0.26 and P = 0.26, respectively), as with collagen orientation, the vascular canal orientation is predominantly longitudinal. The longitudinal organization of both the vascular canals and the collagen fibres is probably a consequence of longitudinal shifting of subperiosteal osteoid during femoral lengthening. When taken together, these data suggest that growth dynamics is the dominant influence on the histological organization of primary bony tissues in alligator femora.
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Affiliation(s)
- Andrew H Lee
- Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, Berkeley, CA 94720- 3140, USA.
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