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Mohamed FF, Chavez MB, Huggins S, Bertels J, Falck A, Suva LJ, Foster BL, Gaddy D. Dentoalveolar Defects of Hypophosphatasia are Recapitulated in a Sheep Knock-In Model. J Bone Miner Res 2022; 37:2005-2017. [PMID: 36053890 PMCID: PMC9613530 DOI: 10.1002/jbmr.4666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 06/17/2022] [Accepted: 07/27/2022] [Indexed: 11/11/2022]
Abstract
Hypophosphatasia (HPP) is the inherited error-of-metabolism caused by mutations in ALPL, reducing the function of tissue-nonspecific alkaline phosphatase (TNAP/TNALP/TNSALP). HPP is characterized by defective skeletal and dental mineralization and is categorized into several clinical subtypes based on age of onset and severity of manifestations, though premature tooth loss from acellular cementum defects is common across most HPP subtypes. Genotype-phenotype associations and mechanisms underlying musculoskeletal, dental, and other defects remain poorly characterized. Murine models that have provided significant insights into HPP pathophysiology also carry limitations including monophyodont dentition, lack of osteonal remodeling of cortical bone, and differing patterns of skeletal growth. To address this, we generated the first gene-edited large-animal model of HPP in sheep via CRISPR/Cas9-mediated knock-in of a missense mutation (c.1077C>G; p.I359M) associated with skeletal and dental manifestations in humans. We hypothesized that this HPP sheep model would recapitulate the human dentoalveolar manifestations of HPP. Compared to wild-type (WT), compound heterozygous (cHet) sheep with one null allele and the other with the targeted mutant allele exhibited the most severe alveolar bone, acellular cementum, and dentin hypomineralization defects. Sheep homozygous for the mutant allele (Hom) showed alveolar bone and hypomineralization effects and trends in dentin and cementum, whereas sheep heterozygous (Het) for the mutation did not exhibit significant effects. Important insights gained include existence of early alveolar bone defects that may contribute to tooth loss in HPP, observation of severe mantle dentin hypomineralization in an HPP animal model, association of cementum hypoplasia with genotype, and correlation of dentoalveolar defects with alkaline phosphatase (ALP) levels. The sheep model of HPP faithfully recapitulated dentoalveolar defects reported in individuals with HPP, providing a new translational model for studies into etiopathology and novel therapies of this disorder, as well as proof-of-principle that genetically engineered large sheep models can replicate human dentoalveolar disorders. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Fatma F Mohamed
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Michael B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Shannon Huggins
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Joshua Bertels
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Alyssa Falck
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Larry J Suva
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Brian L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Dana Gaddy
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
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Holton NE, Piche A, Yokley TR. Integration of the nasal complex: Implications for developmental and evolutionary change in modern humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:791-802. [PMID: 29566424 DOI: 10.1002/ajpa.23466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/12/2018] [Accepted: 03/06/2018] [Indexed: 12/23/2022]
Abstract
OBJECTIVES Assessing the strength of integration among different regions of the modern human nasal complex is important for developing a more thorough understanding of the determinants of nasal morphology. Given the morphogenetic influence of cartilage on adjacent intramembranous growth sites, the interaction between chondrocranial- versus intramembranous-derived nasal structures may have a significant influence on patterns of nasal variation. The purpose of this study is to examine integration between the chondrocranial- and intramembranous-derived regions of the nasal complex. MATERIALS AND METHODS Using computed tomograph (CT) scans, we collected three-dimensional coordinate landmark data from a static adult sample (n = 62). First, using centroid size, and the symmetric and asymmetric components of shape variation, we examined the strength of integration between landmarks representing chondrocranial-derived structures (e.g., ethmoid, external nasal cartilages) and landmarks representing intramembranous-derived structures (nasal floor, anterior nasal aperture, etc.). Second, given that the strength of integration is a relative measure, we compared integration between chondrocranial- and intramembranous-derived structures to the more modularized external and internal regions of the nasal complex. RESULTS There was significant moderate morphological integration between chondrocranial- versus intramembranous-derived regions of the nasal complex. Moreover, integration between chondrocranial- versus intramembranous-derived structures was consistently stronger when compared to external versus internal regions for both the symmetric and asymmetric components of variation. Thus, more covariation within the nasal complex could be explained by the relationship between chondrocranial- and intramembranous-derived structures. CONCLUSIONS Our results suggest that the interaction between chondrocranial- and intramembranous-derived structures may be an important determinant in the patterning of nasal complex variation.
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Affiliation(s)
- Nathan E Holton
- Department of Orthodontics, The University of Iowa, Iowa.,Department of Anthropology, The University of Iowa, Iowa
| | - Amanda Piche
- College of Dentistry, The University of Iowa, Iowa
| | - Todd R Yokley
- Department of Sociology and Anthropology, Metropolitan State University, Denver
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Peltomäki T, Kreiborg S, Pedersen TK, Ogaard B. Craniofacial growth and dento-alveolar development in juvenile idiopathic arthritis patients. Semin Orthod 2015. [DOI: 10.1053/j.sodo.2015.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Valla K, Halazonetis DJ. Correlation of 2D:4D digit ratio and craniofacial shape in prepubertal children. Am J Hum Biol 2014; 26:337-46. [PMID: 24470061 DOI: 10.1002/ajhb.22512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 12/23/2013] [Accepted: 01/08/2014] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES The 2D:4D ratio is sexually dimorphic and is considered a proxy of prenatal androgen levels, or, according to recent evidence, is related to genes involved in ocular and palate development. Our aim was to investigate correlation between the 2D:4D ratio and the shape of the craniofacial skeleton in a population of prepubertal children. METHODS We conducted a cross-sectional study in a group of 58 male and 59 female prepubertal children aged 7-12 years. Craniofacial shape was evaluated using 15 skeletal landmarks on lateral cephalometric radiographs and fingers were measured with a computer-assisted procedure that involved tracing the finger outline. Geometric morphometric analysis was applied to the craniofacial landmarks and multivariate regression between digit ratios and craniofacial shape was computed in shape space and form space. RESULTS The male 2D:4D ratio was smaller than the female ratio (Cohen's d: 0.275 left hand, 0.126 right hand), but the difference was not statistically significant. Craniofacial shape did not show sexual dimorphism, but males were larger than females. No correlation was found between digit ratio and craniofacial shape in prepubertal children, either for the whole sample or for any of the two sex groups. CONCLUSIONS As several factors might be involved in the development and growth of both the craniofacial complex and fingers, the 2D:4D ratio, a putative proxy for fetal sex-hormone levels, is probably unable to impose a measurable effect within the variation of a normal population. Future research needs to examine an adult sample for potential covariation arising after the pubertal growth spurt.
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Affiliation(s)
- Kalliopy Valla
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Greece
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New therapeutics in promoting and modulating mandibular growth in cases with mandibular hypoplasia. BIOMED RESEARCH INTERNATIONAL 2013; 2013:789679. [PMID: 23819121 PMCID: PMC3681221 DOI: 10.1155/2013/789679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 04/10/2013] [Accepted: 04/18/2013] [Indexed: 01/25/2023]
Abstract
Children with mandibular growth deficiency may develop airway obstruction. The standard treatment of severe airway obstruction involves invasive procedures such as tracheostomy. Mandibular distraction osteogenesis has been proposed in neonates with mandibular deficiency as a treatment option to avoid tracheostomy procedure later in life. Both tracheostomy and distraction osteogenesis procedures suffer from substantial shortcomings including scarring, unpredictability, and surgical complications. Forward jaw positioning appliances have been also used to enhance mandible growth. However, the effectiveness of these appliances is limited and lacks predictability. Current and future approaches to enhance mandibular growth, both experimental and clinical trials, and their effectiveness are presented and discussed.
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Deleurant Y, Zimmermann A, Peltomki T. Hemimandibular elongation: treatment and long-term follow-up. Orthod Craniofac Res 2008; 11:172-9. [DOI: 10.1111/j.1601-6343.2008.00427.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Othman H, Thonar EJ, Mao JJ. Modulation of neonatal growth plate development by ex vivo intermittent mechanical stress. J Biomech 2007; 40:2686-93. [PMID: 17346717 PMCID: PMC4035018 DOI: 10.1016/j.jbiomech.2006.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 12/14/2006] [Indexed: 01/17/2023]
Abstract
Although growth plate response to mechanical stress has been increasingly studied, our understanding of mechanical modulation of neonatal growth plate is incomplete, especially concerning biochemical changes. This study was designed to explore the cellular and biochemical responses of the cranial base growth plate (CBGP) explant upon cyclic loading. The growth plate with subchondral bone was aseptically isolated from each of 24 neonatal rabbits and fixated in an organ culture system. Cyclic loading was applied to growth plate explants at 200 mN and 1 Hz for 60 min (N=12), whereas control explants were immersed in organ culture for 60 min without mechanical loading (N=12). Computerized image analysis revealed that cyclic loading induced significantly more proliferating chondrocytes than unloaded controls (p<0.001), as well as significantly higher growth plate height at 856+/-30 microm than the unloaded controls at 830+/-36 microm (p<0.05). Immunoblotting with monoclonal antibodies (mAb) disclosed that the average mAb binding area for chondroitin sulfate was significantly higher in the loaded specimens than the unloaded controls at (p<0.001). The average mAb binding area for keratan sulfate was also significantly higher in the loaded specimens than the unloaded controls (p<0.01). Biochemical analysis showed that the average total hyaluronan content of loaded specimens at 0.25+/-0.06 microg/microg DNA was significantly higher than the unloaded controls at 0.09+/-0.05 microg/microg DNA (p<0.01). Taken together, these data suggest that brief doses of cyclic, intermittent forces activate cellular and molecular responses in the CBGP ex vivo. Whether hyaluronan-mediated pathway is involved in the biological responses of growth plate to mechanical loading warrants additional investigations.
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Affiliation(s)
- Hasan Othman
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Sciences, College of Dental Medicine, Columbia University, 630 W. 168 Street, PH7 East SDOS, New York, NY 10032, USA
| | - Eugene J. Thonar
- Departments of Biochemistry and Orthopaedics, Rush University, 1735 W. Harrison Street, Suite 526 Cohn Building, Chicago, IL 60612, USA
| | - Jeremy J. Mao
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Sciences, College of Dental Medicine, Columbia University, 630 W. 168 Street, PH7 East SDOS, New York, NY 10032, USA
- Corresponding author. Tel.: +1 212 305 4475; fax: +1 212 342 0199. (J.J. Mao)
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Abstract
Endochondral ossification at the caudal junctions of the cartilaginous nasal septum, in combination with interstitial expansion of the septum, is thought to displace the facial skeleton away from the neurocranium. However, the rate of endochondral ossification has not been measured or related to rates of septal enlargement. This study examined endochondral ossification at these junctions in mice from postnatal days 0-15, in the context of known cranial growth sites, the synchondroses. BrdU labeling was used to compare cell division at the septoethmoidal and septopresphenoidal junctions with cell division at the synchondroses, and double-fluorochrome labeling was used to measure mineralization rate. The results showed that the septoethmoidal and septopresphenoidal junctions develop the characteristic morphology of growth plates postnatally, and that the pattern of cell division is similar to that of synchondroses. Mineralization at these junctions occurred at rates that were not statistically different from those of the synchondroses. However, the cartilaginous septum increased in length much more rapidly than could be explained by caudal growth, implying that interstitial expansion is the more important contributor to septal growth.
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Savontaus M, Rintala-Jämsä M, Morko J, Rönning O, Metsäranta M, Vuorio E. Abnormal craniofacial development and expression patterns of extracellular matrix components in transgenic Del1 mice harboring a deletion mutation in the type II collagen gene. Orthod Craniofac Res 2004; 7:216-26. [PMID: 15562585 DOI: 10.1111/j.1601-6343.2004.00304.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To analyze the effect of a type II collagen mutation on craniofacial development in transgenic Del1 mice. DESIGN Samples from homozygous (+/+) and heterozygous (+/-) transgenic Del1 mice harboring mutations in the type II collagen gene as well as non-transgenic (-/-) littermates were collected at days 12.5, 14.5, 16.5 and 18.5 of gestation. The cartilaginous and bony elements of the craniofacial skeleton were analyzed after staining with alcian blue, alizarin red S and von Kossa. The expression patterns of type II, IX and X collagens and aggrecan were analyzed by immunohistochemistry and in situ hybridization. RESULTS Several abnormalities were observed in the craniofacial skeleton of transgenic Del1 mice. These include an overall retardation of chondrogenesis and osteogenesis in Del1 +/+ mice, and to a lesser extent also in Del1+/- mice. Characteristic findings in Del1 +/+ mice included a reduced anterioposterior length, a smaller size of the mandible, a palatal cleft and a downward bending snout. We also detected retarded ossification of calvarial bones in Del1 +/+ and +/- mice when compared with Del1 -/- mice. A surprising finding was the presence of both type II and X collagens and their mRNAs in the periosteum of the cranial base. CONCLUSION The present study confirms the important role of type II collagen mutation in craniofacial development and growth. In addition to affecting endochondral ossification, the type II collagen mutation also disturbs intramembranous ossification in the developing craniofacial skeleton.
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Affiliation(s)
- M Savontaus
- Department of Medical Biochemistry and Molecular Biology, University of Turku, Turku, Finland
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Merchant TE, Nguyen L, Nguyen D, Wu S, Hudson MM, Kaste SC. Differential attenuation of clavicle growth after asymmetric mantle radiotherapy. Int J Radiat Oncol Biol Phys 2004; 59:556-61. [PMID: 15145176 DOI: 10.1016/j.ijrobp.2003.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 11/03/2003] [Accepted: 11/10/2003] [Indexed: 10/26/2022]
Abstract
PURPOSE To determine the effects of 15 Gy on bone growth as a function of time and age by comparing clavicle length before and after asymmetric mantle irradiation in pediatric patients. METHODS AND MATERIALS We measured the lengths of both clavicles from radiographs made before and after radiotherapy (median follow-up, 39.6 months), in 15 children (median age, 13.3 years) with early-stage Hodgkin's disease treated with combined modality therapy. The intercepts and slopes of regression lines for individual patients were used to form an estimating regression curve for the population. RESULTS The irradiated volume, patient age, and time elapsed after treatment influenced the measured growth. Fully irradiated clavicles grew 1.3 +/- 0.3 cm, significantly less (0.5 cm; p = 0.007) than did the partially irradiated clavicles. The difference between partially and fully irradiated clavicle lengths was statistically significant, regardless of age. Also, the growth rate of partially and fully irradiated clavicles was significantly different between younger (mean age, 9.9 years) and older (mean age, 16.4 years) patients (p = 0.036). CONCLUSION Clavicle growth is vulnerable to radiation doses as low as 15 Gy, and patient age at the time of irradiation influences the growth rate.
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Affiliation(s)
- Thomas E Merchant
- Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105-2794, USA.
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Delatte M, Von den Hoff JW, van Rheden REM, Kuijpers-Jagtman AM. Primary and secondary cartilages of the neonatal rat: the femoral head and the mandibular condyle. Eur J Oral Sci 2004; 112:156-62. [PMID: 15056113 DOI: 10.1111/j.0909-8836.2004.00108.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary and secondary cartilages differ in embryonic origin and in histological organization, and are generally considered to have a different mode of growth. However, few studies have directly compared the two types of cartilage of the same animal at the same age. Therefore, we analysed several histological and biochemical differences between secondary cartilage of the mandibular condyle and primary cartilage of the femoral head of 4-d-old rats. We evaluated the tissue organization, the level of DNA and glycosaminoglycan (GAG) synthesis, and the GAG and collagen content. The expression of collagen types I, II and III and of receptors for insulin-like growth factor (IGF)-I, fibroblast growth factor (FGF), and transforming growth factor (TGF)-beta were investigated by immunohistochemistry. The ex vivo DNA and GAG synthesis as well as the GAG content of femoral heads were much higher than that of mandibular condyles. Mandibular condyles expressed both collagen types I and II, while femoral heads expressed only type II collagen. In the mandibular condyles, receptors for IGF-I, FGF, and TGF-beta were observed mainly in the superficial layers, whereas they were found throughout the entire femoral head. In conclusion, major differences were found between both types of cartilage, which might be related to their specific functional demands.
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Affiliation(s)
- Myriam Delatte
- Department of Orthodontics, Université Catholique de Louvain, Cliniques Universitaires St Luc, Brussels, Belgium
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Peltomäki T, Quevedo LA, Jeldes G, Rönning O. Histology of surgically removed overgrown osteochondral rib grafts. J Craniomaxillofac Surg 2002; 30:355-60. [PMID: 12425990 DOI: 10.1054/jcms.2002.0327] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Osteochondral rib grafts are most commonly used for mandibular condylar replacements. However, when used in growing patients, unpredictable growth of the constructed condyle/ramus is a common complication. Clinically two types of overgrowth, linear or exuberant, have been described. PURPOSE In order to investigate growth disorders associated with osteochondral rib grafts in children, overgrown grafts were examined histologically. PATIENTS AND METHODS The material consisted of seven samples (six patients) of osteochondral rib grafts, that had been removed due to overgrowth. RESULTS Examination revealed that the clinical type of overgrowth was not related to any specific microarchitecture, which in itself, showed considerable variation. In three of the samples, a typical endochondral ossification zone was seen and in two others, signs of metaplasia, i.e. a gradual transformation of the cartilage cells into osteocytes, were noted. CONCLUSIONS The study reveals that the clinical type of overgrowth, linear or exuberant, cannot be related to any typical histological finding. Furthermore, the findings suggest that local factors, such as mandibular movements and loading of the reconstructed condyle may have an effect on the structure of the osteochondral rib graft, and eventually on its growth.
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Affiliation(s)
- Timo Peltomäki
- Department of Oral Development and Orthodontics, Institute of Dentistry, University of Turku, Finland.
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Visnapuu V, Peltomäki T, Rönning O, Syrjänen S. Distribution of insulin-like growth factor-I mRNA in the mandibular condyle and rib cartilage of the rat during growth. Arch Oral Biol 2002; 47:791-8. [PMID: 12446186 DOI: 10.1016/s0003-9969(02)00115-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study makes a molecular biological comparison of primary and secondary cartilage at an early phase of postnatal development. The distribution of insulin-like growth factor-I (IGF-I) mRNA expression in the mandibular condyle and rib cartilage of 1-28-day-old rats was examined after in situ hybridisation using an oligo probe cocktail for IGF-I mRNA. In the condyle, expression was localised to a narrow strip under the articular layer where the cells are undifferentiated. Essentially, no differences were found in IGF-I synthesis within three samples from the same age group or between different age groups. In rib cartilage, IGF-I mRNA was localised within the germinative, proliferative and early hypertrophic cell layers in 1-28-day-old rats. Again, there were no differences in expression among animals of the same age or as a function of age. This pattern of IGF-I mRNA expression indicates that IGF-I synthesis during growth of the mandibular condylar cartilage is different from that of costal cartilage. The findings shed light on the problem of overgrowth often associated with the use of costochondral grafts to replace defective mandibular condyles.
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Affiliation(s)
- V Visnapuu
- Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520, Turku, Finland.
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Peltomäki T, Vähätalo K, Rönning O. The effect of a unilateral costochondral graft on the growth of the marmoset mandible. J Oral Maxillofac Surg 2002; 60:1307-14; discussion 1314-5. [PMID: 12420265 DOI: 10.1053/joms.2002.35729] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE The purpose of the investigation was to examine growth of the mandible after costochondral grafting with special reference to the amount of cartilage included in the grafts. MATERIALS AND METHODS The material consisted of 5 growing and 3 adult marmoset monkeys, Callithrix jacchus, in which the condylar process was removed unilaterally and replaced with a costochondral graft (CCG) containing either a short or long cartilage end. Growing animals were followed for 15 months until they attained maturity; and adult animals were followed for 13 months. Measurements made on frontal radiographs performed bimonthly, and direct measurements made on dry mandibles and crania at the end of the experiment, were used to evaluate the growth of the mandible and glenoid fossa. RESULTS Longitudinal cephalometric evaluation revealed a gradual deviation of the lower dental midline to the unoperated side in growing monkeys with a long cartilage transplant. In all other animals, virtually no midline deviation occurred. Measurements on dry mandibles showed that the length and ramus height were longer in growing animals with long cartilage transplants compared with those with short cartilage transplants. In adult animals, the amount of cartilage did not make any difference with regard to the mandibular measurements. Enlargement of the articulating head on the grafted side was recorded in all animals. A morphologic change in the glenoid fossa of growing monkeys with a long cartilage transplant was also noted. CONCLUSIONS The findings of this investigation indicate that depending on the amount of cartilage in a unilateral CCG, a tissue-separating force is generated in growing monkeys, capable of propelling the mandible to the unoperated side. This gradual overgrowth occurs during the entire growth period, indicating a strong hormonal and growth factor influence on the growth process. Jaw function may have an effect on the articulating surface of the CCG, seen as enlarged articulating head on the grafted side in all animals.
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Affiliation(s)
- Timo Peltomäki
- Department of Oral Development and Orthodontics, Institute of Dentistry, University of Turku, Finland.
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Wang X, Mao JJ. Chondrocyte proliferation of the cranial base cartilage upon in vivo mechanical stresses. J Dent Res 2002; 81:701-5. [PMID: 12351669 DOI: 10.1177/154405910208101009] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Whereas the growth of the cranial base cartilage is thought to be regulated solely by genes, epiphyseal growth plates are known to respond to mechanical stresses. This disparity has led to our hypothesis that chondrocyte proliferation is accelerated by mechanical stimuli above natural growth. Two-Newton tensile forces with static and cyclic waveforms were delivered in vivo to the premaxillae of actively growing rabbits for 20 min/day over 12 consecutive days. The average number of BrdU-labeled chondrocytes in the proliferating zone treated with cyclic forces was significantly higher than both static forces of matching peak magnitude and sham controls representing natural chondral growth. Cyclic forces also evoked greater area of the proliferating zone than both static forces and sham controls. Thus, chondrocyte proliferation is enhanced by mechanical stresses in vivo, especially those with oscillatory waveform. Analysis of these data suggests that genetically coded chondral growth is up-regulated by mechanical signals.
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Affiliation(s)
- X Wang
- Skeletal Tissue Engineering Laboratory, Rm 237, Department of Orthodontics and Bioengineering, Univ. of Illinois at Chicago MC 841, 801 South Paulina Street, Chicago, IL 60612-7211, USA
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Wang X, Mao JJ. Accelerated chondrogenesis of the rabbit cranial base growth plate by oscillatory mechanical stimuli. J Bone Miner Res 2002; 17:1843-50. [PMID: 12369788 DOI: 10.1359/jbmr.2002.17.10.1843] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
How mechanical stimuli modulate chondral growth is not well understood. To test a hypothesis that chondral growth is accelerated by oscillatory mechanical stimuli rather than the peak magnitude of mechanical force, we delivered 2-N tensile forces with static (frequency = 0 Hz) and cyclic (f = 1 Hz) profiles noninvasively to the maxillae of growing New Zealand white rabbits for 20 minutes/day over 12 days. Computerized histomorphometry revealed significantly greater maximum height of the cranial base growth plate (GP) treated with cyclic forces (870 +/- 130 microm) than static forces (654 +/- 29 microm) and sham controls (566 +/- 47 microm). In addition, the average total GP area treated with cyclic forces (2.63 +/- 0.17 mm2) was significantly greater than static forces (2.12 +/- 0.99 mm2) and sham controls (1.65 +/- 0.13 mm2). The proliferating zone of GPs treated with cyclic forces (158 +/- 38.5 microm) was significantly longer than the corresponding zones of static forces (117 +/- 8.6 microm) and sham controls (54 +/- 14.9 microm). The average number of chondrocytes in the proliferating zone treated with cyclic forces (1045 +/- 127) was significantly greater than static forces (632 +/- 85) and sham controls (632 +/- 60) in standardized grids. Like natural GPs, the cartilage matrix treated with cyclic and static tensile forces consisted of abundant aggrecan-like proteoglycans. These findings indicate that oscillatory components of mechanical force rather than its peak magnitude are potent anabolic stimulus for chondral growth. A cascade of oscillatory mechanical stimuli is likely capable of engineering chondral growth beyond naturally occurring chondrogenesis.
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Affiliation(s)
- Xin Wang
- Department of Orthodontics, University of Illinois at Chicago, 60612-7211, USA
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Visnapuu V, Peltomäki T, Rönning O, Vahlberg T, Helenius H. Growth hormone and insulin-like growth factor I receptors in the temporomandibular joint of the rat. J Dent Res 2001; 80:1903-7. [PMID: 11706949 DOI: 10.1177/00220345010800100801] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
While there are numerous investigations on hormonal control of long bone epiphyseal growth, corresponding knowledge is sparse concerning the condylar cartilage. We investigated the distribution of growth hormone (GH) and insulin-like growth factor I (IGF-I) receptors in the temporomandibular joint (TMJ), especially the condyle, and compared the findings with information of long bone epiphyseal plates. The localization of the receptors was examined in vivo by immunohistochemical methods in one- to 21-day-old rats. GH receptors were detected in various components of the TMJ, but not in the fibrous articular surface or in the cartilage layers of the condyle. IGF-I receptors were found in the fibrous articular surface of the condyle and particularly in the superior and posterosuperior regions of the condylar cartilage, the depth of the labeled cell layer increasing significantly with age. It is evident that the expression of GH and IGF-I receptors is area-specific in the TMJ. Early post-natal growth and development of the mandibular condylar cartilage seem to be IGF-I-dependent but not directly dependent on GH.
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Affiliation(s)
- V Visnapuu
- Institute of Dentistry, University of Turku, Finland.
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Peltomäki T, Vendittelli BL. Craniofacial shortening by contraction osteogenesis: an experimental model. Plast Reconstr Surg 2000; 106:1657-8. [PMID: 11129204 DOI: 10.1097/00006534-200012000-00047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kiliaridis S, Thilander B, Kjellberg H, Topouzelis N, Zafiriadis A. Effect of low masticatory function on condylar growth: a morphometric study in the rat. Am J Orthod Dentofacial Orthop 1999; 116:121-5. [PMID: 10434083 DOI: 10.1016/s0889-5406(99)70207-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of this study was to estimate the influence of functional alterations on the size of the mandibular condyle and to elucidate in detail, by means of histomorphometric analysis, the effect of changing the consistency of the diet on different portions of the condylar cartilage in growing rats. Forty growing rats were randomly divided into 2 groups. One group received the normal hard diet for rats; the other group received a standardized soft diet. The experimental period was 28 days. Ten animals from each group were used for gross morphometric analysis; the other 10 animals were used for histologic analysis of the condyle. The morphometric analysis of the condylar cartilage was based on the 25th, 50th, and 75th percentiles of the mediolateral sections of the condyles. The sections were divided into 3 parts: the anterior, intermediate, and posterior part; 4 measurements were performed in each. Significant differences were found in the condylar length and width between the groups, the soft diet group having a smaller condyle. The histomorphometric analysis of cartilage thickness showed significant differences between the 2 groups, being thinner in the anterior part and thicker in the posterior part of the condyle in the soft diet group. These routine histologic findings cannot explain the gross morphologic differences in the condylar size between the groups; this means that increased condylar cartilage thickness is not necessarily evidence of increased condylar growth. The results from this study indicate that a low masticatory function leads to decreased growth of the condyle and changes in the thickness of the cartilage. This may be the effect of an alteration in the stress distribution in the temporomandibular joint area, because of the absence of large masticatory forces.
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Affiliation(s)
- S Kiliaridis
- Department of Orthodontics, University of Geneva, Switzerland
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Schmuth GP. Considerations of functional aspects in dentofacial orthopedics and orthodontics: Sheldon Friel Memorial Lecture. Am J Orthod Dentofacial Orthop 1999; 115:373-81. [PMID: 10194280 DOI: 10.1016/s0889-5406(99)70255-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- G P Schmuth
- Zentrum ZMK der Universitat Bonn, Welschnonnenstrasse 17, D53111 Bonn, Germany
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