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Peiffer M, Duquesne K, Van Oevelen A, Burssens A, De Mits S, Maas SA, Atkins PR, Anderson AE, Audenaert EA. Validation of a personalized ligament-constraining discrete element framework for computing ankle joint contact mechanics. Comput Methods Programs Biomed 2023; 231:107366. [PMID: 36720186 DOI: 10.1016/j.cmpb.2023.107366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/09/2023] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND OBJECTIVE Computer simulations of joint contact mechanics have great merit to improve our current understanding of articular ankle pathology. Owed to its computational simplicity, discrete element analysis (DEA) is an encouraging alternative to finite element analysis (FEA). However, previous DEA models lack subject-specific anatomy and may oversimplify the biomechanics of the ankle. The objective of this study was to develop and validate a personalized DEA framework that permits movement of the fibula and incorporates personalized cartilage thickness as well as ligamentous constraints. METHODS A linear and non-linear DEA framework, representing cartilage as compressive springs, was established, verified, and validated. Three-dimensional (3D) bony ankle models were constructed from cadaveric lower limb CT scans imaged during application of weight (85 kg) and/or torque (10 Nm). These 3D models were used to generate cartilage thickness and ligament insertion sites based on a previously validated statistical shape model. Ligaments were modelled as non-linear tension-only springs. Validation of contact stress prediction was performed using a simple, axially constrained tibiotalar DEA model against an equivalent FEA model. Validation of ligamentous constraints compared the final position of the ankle mortise to that of the cadaver after application of torque and sequential ligament sectioning. Finally, a combined ligamentous-constraining DEA model was validated for predicted contact stress against an equivalent ligament-constraining FEA model. RESULTS The linear and non-linear DEA model reproduced a mean articular contact stress within 0.36 MPa and 0.39 MPa of the FEA calculated stress, respectively. With respect to the ligamentous validation, the DEA ligament-balancing algorithm could reproduce the position of the distal fibula within the ankle mortise to within 0.97 mm of the experimental observed distal fibula. When combining the ligament-constraining and contact stress algorithm, DEA was able to reproduce a mean articular contact stress to within 0.50 MPa of the FEA calculated contact stress. CONCLUSION The DEA framework presented herein offers a computationally efficient alternative to FEA for the prediction of contact stress in the ankle joint, manifesting its potential to enhance the mechanical understanding of articular ankle pathologies on both a patient-specific and population-wide level. The novelty of this model lies in its personalized nature, inclusion of the distal tibiofibular joint and the use of non-linear ligament balancing to maintain the physiological ankle joint articulation.
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Affiliation(s)
- M Peiffer
- Department of Orthopaedics and Traumatology, Ghent University Hospital, Ghent, Belgium; Department of Human Structure and Repair, Ghent University, Ghent, Belgium; Department of Orthopaedics, University of Utah School of Medicine, Salt Lake City, Utah, USA.
| | - K Duquesne
- Department of Orthopaedics and Traumatology, Ghent University Hospital, Ghent, Belgium; Department of Human Structure and Repair, Ghent University, Ghent, Belgium
| | - A Van Oevelen
- Department of Orthopaedics and Traumatology, Ghent University Hospital, Ghent, Belgium; Department of Human Structure and Repair, Ghent University, Ghent, Belgium
| | - A Burssens
- Department of Orthopaedics and Traumatology, Ghent University Hospital, Ghent, Belgium
| | - S De Mits
- Department of Reumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium; Smart Space, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - S A Maas
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - P R Atkins
- Department of Orthopaedics, University of Utah School of Medicine, Salt Lake City, Utah, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah, USA
| | - A E Anderson
- Department of Orthopaedics, University of Utah School of Medicine, Salt Lake City, Utah, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA; Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
| | - E A Audenaert
- Department of Orthopaedics and Traumatology, Ghent University Hospital, Ghent, Belgium; Department of Human Structure and Repair, Ghent University, Ghent, Belgium; Department of Trauma and Orthopedics, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK; Department of Electromechanics, Op3Mech research group, University of Antwerp, Antwerp, Belgium
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Woo Y, Wright SM, Maas SA, Alley TL, Caddle LB, Kamdar S, Affourtit J, Foreman O, Akeson EC, Shaffer D, Bronson RT, Morse HC, Roopenian D, Mills KD. The nonhomologous end joining factor Artemis suppresses multi-tissue tumor formation and prevents loss of heterozygosity. Oncogene 2007; 26:6010-20. [PMID: 17384673 DOI: 10.1038/sj.onc.1210430] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nonhomologous end joining (NHEJ) is a critical DNA repair pathway, with proposed tumor suppression functions in many tissues. Mutations in the NHEJ factor ARTEMIS cause radiation-sensitive severe combined immunodeficiency in humans and may increase susceptibility to lymphoma in some settings. We now report that deficiency for Artemis (encoded by Dclre1c/Art in mouse) accelerates tumorigenesis in several tissues in a Trp53 heterozygous setting, revealing tumor suppression roles for NHEJ in lymphoid and non-lymphoid cells. We also show that B-lineage lymphomas in these mice undergo loss of Trp53 heterozygosity by allele replacement, but arise by mechanisms distinct from those in Art Trp53 double null mice. These findings demonstrate a general tumor suppression function for NHEJ, and reveal that interplay between NHEJ and Trp53 loss of heterozygosity influences the sequence of multi-hit oncogenesis. We present a model where p53 status at the time of tumor initiation is a key determinant of subsequent oncogenic mechanisms. Because Art deficient mice represent a model for radiation-sensitive severe combined immunodeficiency, our findings suggest that these patients may be at risk for both lymphoid and non-lymphoid cancers.
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Affiliation(s)
- Y Woo
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
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Scott IC, Blitz IL, Pappano WN, Maas SA, Cho KW, Greenspan DS. Homologues of Twisted gastrulation are extracellular cofactors in antagonism of BMP signalling. Nature 2001; 410:475-8. [PMID: 11260715 DOI: 10.1038/35068572] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Twisted gastrulation (TSG) is involved in specifying the dorsal-most cell fate in Drosophila embryos, but its mechanism of action is poorly understood. TSG has been proposed to modify the action of Short gastrulation (SOG), thereby increasing signalling by the bone morphogenetic protein (BMP) Decapentaplegic. SOG, an inhibitor of BMP signalling, is in turn inactivated by the protease Tolloid. Here we identify Tsg gene products from human, mouse, Xenopus, zebrafish and chick. Expression patterns in mouse and Xenopus embryos are consistent with in vivo interactions between Tsg, BMPs and the vertebrate SOG orthologue, chordin. We show that Tsg binds both the vertebrate Decapentaplegic orthologue BMP4 and chordin, and that these interactions have multiple effects. Tsg increases chordin's binding of BMP4, potentiates chordin's ability to induce secondary axes in Xenopus embryos, and enhances chordin cleavage by vertebrate tolloid-related proteases at a site poorly used in Tsg's absence; also, the presence of Tsg enhances the secondary axis-inducing activity of two products of chordin cleavage. We conclude that Tsg acts as a cofactor in chordin's antagonism of BMP signalling.
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Affiliation(s)
- I C Scott
- Department of Pathology and Laboratory Medicine, University of Wisconsin Medical School, Madison 53706, USA
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Scott IC, Blitz IL, Pappano WN, Imamura Y, Clark TG, Steiglitz BM, Thomas CL, Maas SA, Takahara K, Cho KW, Greenspan DS. Mammalian BMP-1/Tolloid-related metalloproteinases, including novel family member mammalian Tolloid-like 2, have differential enzymatic activities and distributions of expression relevant to patterning and skeletogenesis. Dev Biol 1999; 213:283-300. [PMID: 10479448 DOI: 10.1006/dbio.1999.9383] [Citation(s) in RCA: 210] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vertebrate bone morphogenetic protein 1 (BMP-1) and Drosophila Tolloid (TLD) are prototypes of a family of metalloproteases with important roles in various developmental events. BMP-1 affects morphogenesis, at least partly, via biosynthetic processing of fibrillar collagens, while TLD affects dorsal-ventral patterning by releasing TGFbeta-like ligands from latent complexes with the secreted protein Short Gastrulation (SOG). Here, in a screen for additional mammalian members of this family of developmental proteases, we identify novel family member mammalian Tolloid-like 2 (mTLL-2) and compare enzymatic activities and expression domains of all four known mammalian BMP-1/TLD-like proteases [BMP-1, mammalian Tolloid (mTLD), mammalian Tolloid-like 1 (mTLL-1), and mTLL-2]. Despite high sequence similarities, distinct differences are shown in ability to process fibrillar collagen precursors and to cleave Chordin, the vertebrate orthologue of SOG. As previously demonstrated for BMP-1 and mTLD, mTLL-1 is shown to specifically process procollagen C-propeptides at the physiologically relevant site, while mTLL-2 is shown to lack this activity. BMP-1 and mTLL-1 are shown to cleave Chordin, at sites similar to procollagen C-propeptide cleavage sites, and to counteract dorsalizing effects of Chordin upon overexpression in Xenopus embryos. Proteases mTLD and mTLL-2 do not cleave Chordin. Differences in enzymatic activities and expression domains of the four proteases suggest BMP-1 as the major Chordin antagonist in early mammalian embryogenesis and in pre- and postnatal skeletogenesis.
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Affiliation(s)
- I C Scott
- Department of Pathology and Laboratory Medicine, University of Wisconsin Medical School, 1300 University Avenue, Madison, Wisconsin, 53706, USA
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