1
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Omer M, Ngo C, Ali H, Orlovskaya N, Cheong VS, Ballesteros A, Garner MT, Wynn A, Martyniak K, Wei F, Collins BE, Yarmolenko SN, Asiatico J, Kinzel M, Ghosh R, Meckmongkol T, Calder A, Dahir N, Gilbertson TA, Sankar J, Coathup M. The Effect of Omega-9 on Bone Viscoelasticity and Strength in an Ovariectomized Diet-Fed Murine Model. Nutrients 2023; 15:nu15051209. [PMID: 36904208 PMCID: PMC10005705 DOI: 10.3390/nu15051209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 01/30/2023] [Accepted: 02/10/2023] [Indexed: 03/08/2023] Open
Abstract
Few studies have investigated the effect of a monosaturated diet high in ω-9 on osteoporosis. We hypothesized that omega-9 (ω-9) protects ovariectomized (OVX) mice from a decline in bone microarchitecture, tissue loss, and mechanical strength, thereby serving as a modifiable dietary intervention against osteoporotic deterioration. Female C57BL/6J mice were assigned to sham-ovariectomy, ovariectomy, or ovariectomy + estradiol treatment prior to switching their feed to a diet high in ω-9 for 12 weeks. Tibiae were evaluated using DMA, 3-point-bending, histomorphometry, and microCT. A significant decrease in lean mass (p = 0.05), tibial area (p = 0.009), and cross-sectional moment of inertia (p = 0.028) was measured in OVX mice compared to the control. A trend was seen where OVX bone displayed increased elastic modulus, ductility, storage modulus, and loss modulus, suggesting the ω-9 diet paradoxically increased both stiffness and viscosity. This implies beneficial alterations on the macro-structural, and micro-tissue level in OVX bone, potentially decreasing the fracture risk. Supporting this, no significant differences in ultimate, fracture, and yield stresses were measured. A diet high in ω-9 did not prevent microarchitectural deterioration, nevertheless, healthy tibial strength and resistance to fracture was maintained via mechanisms independent of bone structure/shape. Further investigation of ω-9 as a therapeutic in osteoporosis is warranted.
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Affiliation(s)
- Mahmoud Omer
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Christopher Ngo
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA
| | - Hessein Ali
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Nina Orlovskaya
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Vee San Cheong
- Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield S1 3JD, UK
| | | | | | - Austin Wynn
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Kari Martyniak
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA
| | - Fei Wei
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA
| | - Boyce E. Collins
- Engineering Research Center for Revolutionizing Biomaterials, North Carolina A&T State University, Greensboro, NC 27411, USA
| | - Sergey N. Yarmolenko
- Engineering Research Center for Revolutionizing Biomaterials, North Carolina A&T State University, Greensboro, NC 27411, USA
| | - Jackson Asiatico
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Michael Kinzel
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Ranajay Ghosh
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Teerin Meckmongkol
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA
- Department of General Surgery, Nemours Children’s Hospital, Orlando, FL 32827, USA
| | - Ashley Calder
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Naima Dahir
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | | | - Jagannathan Sankar
- Engineering Research Center for Revolutionizing Biomaterials, North Carolina A&T State University, Greensboro, NC 27411, USA
| | - Melanie Coathup
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA
- Correspondence: ; Tel.: +1-407-266-7184
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2
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Omer M, Ali H, Orlovskaya N, Ballesteros A, Cheong VS, Martyniak K, Wei F, Collins BE, Yarmolenko SN, Asiatico J, Kinzel M, Ngo C, Sankar J, Calder A, Gilbertson T, Meckmongkol T, Ghosh R, Coathup M. Omega-9 Modifies Viscoelasticity and Augments Bone Strength and Architecture in a High-Fat Diet-Fed Murine Model. Nutrients 2022; 14:nu14153165. [PMID: 35956341 PMCID: PMC9370223 DOI: 10.3390/nu14153165] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/25/2022] [Accepted: 07/28/2022] [Indexed: 02/04/2023] Open
Abstract
The influence of diet on the development of osteoporosis is significant and not fully understood. This study investigated the effect of diets of varying lipid profiles and ω-3, ω-6 and ω-9 composition on the structural and mechanical properties of bone. The hypothesis studied was that a diet high in saturated fat would induce osteoporosis and produce an overall increased detrimental bony response when compared with a diet high in unsaturated ω-6, or ω-9. Male C57BL/6J mice were fed either a control diet, 50:50 mix (saturated:unsaturated) high in ω-9 (HFD50:50), a diet high in saturated fat (HSF) or a polyunsaturated fat diet high in ω-6 (PUFA) over an 8-week duration. Tibiae were retrieved and evaluated using DMA, 3-point-bending, histomorphometry, and microCT. Mice fed a HSF diet displayed key features characteristic of osteoporosis. The loss tangent was significantly increased in the HFD50:50 diet group compared with control (p = 0.016) and PUFA-fed animals (p = 0.049). HFD50:50-fed mice presented with an increased viscous component, longer tibiae, increased loss modulus (p = 0.009), and ultimate stress, smaller microcracks (p < 0.001), and increased trabecular width (p = 0.002) compared with control animals. A diet high in ω-9 resulted in an overall superior bone response and further analysis of its role in bone health is warranted.
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Affiliation(s)
- Mahmoud Omer
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA; (H.A.); (N.O.); (J.A.); (M.K.); (R.G.)
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
- Correspondence:
| | - Hessein Ali
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA; (H.A.); (N.O.); (J.A.); (M.K.); (R.G.)
| | - Nina Orlovskaya
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA; (H.A.); (N.O.); (J.A.); (M.K.); (R.G.)
| | - Amelia Ballesteros
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA; (A.C.); (T.G.)
| | - Vee San Cheong
- Department of Automatic Control and Systems Engineering, Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield S1 3JD, UK;
| | - Kari Martyniak
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
| | - Fei Wei
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
| | - Boyce E. Collins
- Engineering Research Center for Revolutionizing Biomaterials, North Carolina A&T State University, Greensboro, NC 27411, USA; (B.E.C.); (S.N.Y.); (J.S.)
| | - Sergey N. Yarmolenko
- Engineering Research Center for Revolutionizing Biomaterials, North Carolina A&T State University, Greensboro, NC 27411, USA; (B.E.C.); (S.N.Y.); (J.S.)
| | - Jackson Asiatico
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA; (H.A.); (N.O.); (J.A.); (M.K.); (R.G.)
| | - Michael Kinzel
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA; (H.A.); (N.O.); (J.A.); (M.K.); (R.G.)
| | - Christopher Ngo
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA; (A.C.); (T.G.)
| | - Jagannathan Sankar
- Engineering Research Center for Revolutionizing Biomaterials, North Carolina A&T State University, Greensboro, NC 27411, USA; (B.E.C.); (S.N.Y.); (J.S.)
| | - Ashley Calder
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA; (A.C.); (T.G.)
| | - Timothy Gilbertson
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA; (A.C.); (T.G.)
| | - Teerin Meckmongkol
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
- Department of General Surgery, Nemours Children’s Hospital, Orlando, FL 32827, USA
| | - Ranajay Ghosh
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA; (H.A.); (N.O.); (J.A.); (M.K.); (R.G.)
| | - Melanie Coathup
- Biionix Cluster, University of Central Florida, Orlando, FL 32827, USA; (A.B.); (K.M.); (F.W.); (C.N.); (T.M.); (M.C.)
- College of Medicine, University of Central Florida, Orlando, FL 32827, USA; (A.C.); (T.G.)
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Pereira AR, Trivanović D, Stahlhut P, Rudert M, Groll J, Herrmann M. Preservation of the naïve features of mesenchymal stromal cells in vitro: Comparison of cell- and bone-derived decellularized extracellular matrix. J Tissue Eng 2022; 13:20417314221074453. [PMID: 35154631 PMCID: PMC8829705 DOI: 10.1177/20417314221074453] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/04/2022] [Indexed: 12/14/2022] Open
Abstract
The fate and behavior of bone marrow mesenchymal stem/stromal cells (BM-MSC) is bidirectionally influenced by their microenvironment, the stem cell niche, where a magnitude of biochemical and physical cues communicate in an extremely orchestrated way. It is known that simplified 2D in vitro systems for BM-MSC culture do not represent their naïve physiological environment. Here, we developed four different 2D cell-based decellularized matrices (dECM) and a 3D decellularized human trabecular-bone scaffold (dBone) to evaluate BM-MSC behavior. The obtained cell-derived matrices provided a reliable tool for cell shape-based analyses of typical features associated with osteogenic differentiation at high-throughput level. On the other hand, exploratory proteomics analysis identified native bone-specific proteins selectively expressed in dBone but not in dECM models. Together with its architectural complexity, the physico-chemical properties of dBone triggered the upregulation of stemness associated genes and niche-related protein expression, proving in vitro conservation of the naïve features of BM-MSC.
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Affiliation(s)
- Ana Rita Pereira
- IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, Wuerzburg, Germany
- Bernhard-Heine-Centrum for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
| | - Drenka Trivanović
- IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, Wuerzburg, Germany
- Bernhard-Heine-Centrum for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
| | - Philipp Stahlhut
- Chair for Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Wuerzburg, Wuerzburg, Germany
| | - Maximilian Rudert
- Department of Orthopedic Surgery, Koenig-Ludwig-Haus, University of Wuerzburg, Wuerzburg, Germany
| | - Jürgen Groll
- Chair for Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Wuerzburg, Wuerzburg, Germany
| | - Marietta Herrmann
- IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, Wuerzburg, Germany
- Bernhard-Heine-Centrum for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
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4
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Affiliation(s)
- Guido Raos
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via L. Mancinelli 7, I-20131 Milano, Italy
| | - Bruno Zappone
- Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR-Nanotec), Via P. Bucci, 33/C, 87036 Rende (CS), Italy
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5
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Pereira AR, Lipphaus A, Ergin M, Salehi S, Gehweiler D, Rudert M, Hansmann J, Herrmann M. Modeling of the Human Bone Environment: Mechanical Stimuli Guide Mesenchymal Stem Cell-Extracellular Matrix Interactions. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4431. [PMID: 34442954 PMCID: PMC8398413 DOI: 10.3390/ma14164431] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 02/06/2023]
Abstract
In bone tissue engineering, the design of in vitro models able to recreate both the chemical composition, the structural architecture, and the overall mechanical environment of the native tissue is still often neglected. In this study, we apply a bioreactor system where human bone-marrow hMSCs are seeded in human femoral head-derived decellularized bone scaffolds and subjected to dynamic culture, i.e., shear stress induced by continuous cell culture medium perfusion at 1.7 mL/min flow rate and compressive stress by 10% uniaxial load at 1 Hz for 1 h per day. In silico modeling revealed that continuous medium flow generates a mean shear stress of 8.5 mPa sensed by hMSCs seeded on 3D bone scaffolds. Experimentally, both dynamic conditions improved cell repopulation within the scaffold and boosted ECM production compared with static controls. Early response of hMSCs to mechanical stimuli comprises evident cell shape changes and stronger integrin-mediated adhesion to the matrix. Stress-induced Col6 and SPP1 gene expression suggests an early hMSC commitment towards osteogenic lineage independent of Runx2 signaling. This study provides a foundation for exploring the early effects of external mechanical stimuli on hMSC behavior in a biologically meaningful in vitro environment, opening new opportunities to study bone development, remodeling, and pathologies.
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Affiliation(s)
- Ana Rita Pereira
- IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, 97070 Wuerzburg, Germany; (A.R.P.); (M.E.)
- Bernhard-Heine-Centrum for Locomotion Research, University of Wuerzburg, 97074 Wuerzburg, Germany
| | - Andreas Lipphaus
- Biomechanics Research Group, Ruhr-University Bochum, 44801 Bochum, Germany;
| | - Mert Ergin
- IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, 97070 Wuerzburg, Germany; (A.R.P.); (M.E.)
- Department of Biomaterials, Center of Energy Technology und Materials Science (TAO), University of Bayreuth, 95447 Bayreuth, Germany;
| | - Sahar Salehi
- Department of Biomaterials, Center of Energy Technology und Materials Science (TAO), University of Bayreuth, 95447 Bayreuth, Germany;
| | | | - Maximilian Rudert
- Department of Orthopedic Surgery, Koenig-Ludwig-Haus, University of Wuerzburg, 97074 Wuerzburg, Germany;
| | - Jan Hansmann
- Fraunhofer Institute for Silicate Research, Translational Center for Regenerative Therapies, 97082 Wuerzburg, Germany;
| | - Marietta Herrmann
- IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, 97070 Wuerzburg, Germany; (A.R.P.); (M.E.)
- Bernhard-Heine-Centrum for Locomotion Research, University of Wuerzburg, 97074 Wuerzburg, Germany
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6
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Bailey S, Sroga GE, Hoac B, Katsamenis OL, Wang Z, Bouropoulos N, McKee MD, Sørensen ES, Thurner PJ, Vashishth D. The role of extracellular matrix phosphorylation on energy dissipation in bone. eLife 2020; 9:58184. [PMID: 33295868 PMCID: PMC7746230 DOI: 10.7554/elife.58184] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 12/07/2020] [Indexed: 01/22/2023] Open
Abstract
Protein phosphorylation, critical for cellular regulatory mechanisms, is implicated in various diseases. However, it remains unknown whether heterogeneity in phosphorylation of key structural proteins alters tissue integrity and organ function. Here, osteopontin phosphorylation level declined in hypo- and hyper- phosphatemia mouse models exhibiting skeletal deformities. Phosphorylation increased cohesion between osteopontin polymers, and adhesion of osteopontin to hydroxyapatite, enhancing energy dissipation. Fracture toughness, a measure of bone’s mechanical competence, increased with ex-vivo phosphorylation of wildtype mouse bones and declined with ex-vivo dephosphorylation. In osteopontin-deficient mice, global matrix phosphorylation level was not associated with toughness. Our findings suggest that phosphorylated osteopontin promotes fracture toughness in a dose-dependent manner through increased interfacial bond formation. In the absence of osteopontin, phosphorylation increases electrostatic repulsion, and likely protein alignment and interfilament distance leading to decreased fracture resistance. These mechanisms may be of importance in other connective tissues, and the key to unraveling cell–matrix interactions in diseases.
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Affiliation(s)
- Stacyann Bailey
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, United States
| | - Grazyna E Sroga
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, United States
| | - Betty Hoac
- Faculty of Dentistry, McGill University, Montreal, Canada
| | - Orestis L Katsamenis
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - Zehai Wang
- Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, United States
| | | | - Marc D McKee
- Faculty of Dentistry, McGill University, Montreal, Canada.,Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, Canada
| | - Esben S Sørensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Philipp J Thurner
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria
| | - Deepak Vashishth
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, United States
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7
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Steinbauer P, Rohatschek A, Andriotis O, Bouropoulos N, Liska R, Thurner PJ, Baudis S. Single-Molecule Force Spectroscopy Reveals Adhesion-by-Demand in Statherin at the Protein-Hydroxyapatite Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13292-13300. [PMID: 33118809 PMCID: PMC7660943 DOI: 10.1021/acs.langmuir.0c02325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/09/2020] [Indexed: 06/11/2023]
Abstract
Achieving strong adhesion in wet environments remains a technological challenge in biomedical applications demanding biocompatibility. Attention for adhesive motifs meeting such demands has largely been focused on marine organisms. However, bioadhesion to inorganic surfaces is also present in the human body, in the hard tissues of teeth and bones, and is mediated through serines (S). The specific amino acid sequence DpSpSEEKC has been previously suggested to be responsible for the strong binding abilities of the protein statherin to hydroxyapatite, where pS denotes phosphorylated serine. Notably, similar sequences are present in the non-collagenous bone protein osteopontin (OPN) and the mussel foot protein 5 (Mefp5). OPN has previously been shown to promote fracture toughness and physiological damage formation. Here, we investigated the adhesion strength of the motif D(pS)(pS)EEKC on substrates of hydroxyapatite, TiO2, and mica using atomic force microscopy (AFM) single-molecule force spectroscopy (SMFS). Specifically, we investigated the dependence of adhesion force on phosphorylation of serines by comparing findings with the unphosphorylated variant DSSEEKC. Our results show that high adhesion forces of over 1 nN on hydroxyapatite and on TiO2 are only present for the phosphorylated variant D(pS)(pS)EEKC. This warrants further exploitation of this motif or similar residues in technological applications. Further, the dependence of adhesion force on phosphorylation suggests that biological systems potentially employ an adhesion-by-demand mechanism via expression of enzymes that up- or down-regulate phosphorylation, to increase or decrease adhesion forces, respectively.
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Affiliation(s)
- Patrick Steinbauer
- Christian
Doppler Laboratory for Advanced Polymers for Biomaterials and 3D Printing, TU Wien, Vienna 1060, Austria
- Institute
of Applied Synthetic Chemistry, Division of Macromolecular Chemistry, TU Wien, Vienna 1060, Austria
- Austrian
Cluster for Tissue Regeneration, Vienna 1200, Austria
| | - Andreas Rohatschek
- Institute
of Lightweight Design and Structural Biomechanics, TU Wien, Vienna 1060, Austria
- Austrian
Cluster for Tissue Regeneration, Vienna 1200, Austria
- Biointerface
Doctorate School, TU Wien, Vienna 1060, Austria
| | - Orestis Andriotis
- Institute
of Lightweight Design and Structural Biomechanics, TU Wien, Vienna 1060, Austria
- Austrian
Cluster for Tissue Regeneration, Vienna 1200, Austria
| | - Nikolaos Bouropoulos
- Department
of Materials Science, University of Patras, Rio Patras GR-26504, Greece
- Foundation
for Research and Technology Hellas, Institute of Chemical Engineering
and High Temperature Chemical Processes, FORTH/ICE-HT, Patras 26504, Greece
| | - Robert Liska
- Institute
of Applied Synthetic Chemistry, Division of Macromolecular Chemistry, TU Wien, Vienna 1060, Austria
- Austrian
Cluster for Tissue Regeneration, Vienna 1200, Austria
- Biointerface
Doctorate School, TU Wien, Vienna 1060, Austria
| | - Philipp J. Thurner
- Institute
of Lightweight Design and Structural Biomechanics, TU Wien, Vienna 1060, Austria
- Austrian
Cluster for Tissue Regeneration, Vienna 1200, Austria
- Biointerface
Doctorate School, TU Wien, Vienna 1060, Austria
| | - Stefan Baudis
- Christian
Doppler Laboratory for Advanced Polymers for Biomaterials and 3D Printing, TU Wien, Vienna 1060, Austria
- Institute
of Applied Synthetic Chemistry, Division of Macromolecular Chemistry, TU Wien, Vienna 1060, Austria
- Austrian
Cluster for Tissue Regeneration, Vienna 1200, Austria
- Biointerface
Doctorate School, TU Wien, Vienna 1060, Austria
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8
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An efficient two-scale 3D FE model of the bone fibril array: comparison of anisotropic elastic properties with analytical methods and micro-sample testing. Biomech Model Mechanobiol 2020; 19:2127-2147. [DOI: 10.1007/s10237-020-01328-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 04/11/2020] [Indexed: 12/14/2022]
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9
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Bilotto P, Labate C, De Santo MP, Deepankumar K, Miserez A, Zappone B. Adhesive Properties of Adsorbed Layers of Two Recombinant Mussel Foot Proteins with Different Levels of DOPA and Tyrosine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15481-15490. [PMID: 31465231 DOI: 10.1021/acs.langmuir.9b01730] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Using a surface forces apparatus and an atomic force microscope, we characterized the adhesive properties of adsorbed layers of two recombinant variants of Perna viridis foot protein 5 (PVFP-5), the main surface-binding protein in the adhesive plaque of the Asian green mussel. In one variant, all tyrosine residues were modified into 3,4-dihydroxy-l-phenylalanine (DOPA) during expression using a residue-specific incorporation strategy. DOPA is a key molecular moiety underlying underwater mussel adhesion. In the other variant, all tyrosine residues were preserved. The layer was adsorbed on a mica substrate and pressed against an uncoated surface. While DOPA produced a stronger adhesion than tyrosine in contact with the nanoscopic Si3N4 probe of the atomic force microscope, the two variants produced comparable adhesion on the curved macroscopic mica surfaces of the surface forces apparatus. These findings show that the presence of DOPA is not a sufficient condition to generate strong underwater adhesion. Surface chemistry and contact geometry affect the strength and abundance of protein-surface bonds created during adsorption and surface contact. Importantly, the adsorbed protein layer has a random and dynamic polymer-network structure that should be optimized to transmit the tensile stress generated during surface separation to DOPA surface bonds rather than other weaker bonds.
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Affiliation(s)
- Pierluigi Bilotto
- Dipartimento di Fisica , Università della Calabria , Rende , Italy
- Institute of Applied Physics , Vienna University of Technology , Vienna , Austria
| | - Cristina Labate
- Dipartimento di Fisica , Università della Calabria , Rende , Italy
| | - Maria P De Santo
- Dipartimento di Fisica , Università della Calabria , Rende , Italy
- Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR - Nanotec) , c/o Università della Calabria , Ponte P. Bucci, 33/B , 87036 Rende ( CS ), Italy
| | - Kanagavel Deepankumar
- Biological and Biomimetic Material Laboratory and Center for Biomimetic Sensor Science, School of Materials Science and Engineering , Nanyang Technological University (NTU) , 50 Nanyang Avenue , Singapore 637553
| | - Ali Miserez
- Biological and Biomimetic Material Laboratory and Center for Biomimetic Sensor Science, School of Materials Science and Engineering , Nanyang Technological University (NTU) , 50 Nanyang Avenue , Singapore 637553
- School of Biological Sciences , Nanyang Technological University (NTU) , 60 Nanyang Drive , Singapore 637551
| | - Bruno Zappone
- Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR - Nanotec) , c/o Università della Calabria , Ponte P. Bucci, 33/B , 87036 Rende ( CS ), Italy
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10
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Lai ZB. Numerical investigation of the role of osteopontin on the mechanical strength of biological composites. Comput Methods Biomech Biomed Engin 2019; 22:1186-1196. [DOI: 10.1080/10255842.2019.1647534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Zheng Bo Lai
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD, Australia
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11
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Li X, Pujari-Palmer M, Wenner D, Procter P, Insley G, Engqvist H. Adhesive Cements That Bond Soft Tissue Ex Vivo. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2473. [PMID: 31382566 PMCID: PMC6695630 DOI: 10.3390/ma12152473] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 01/11/2023]
Abstract
The aim of the present study was to evaluate the soft tissue bond strength of a newly developed, monomeric, biomimetic, tissue adhesive called phosphoserine modified cement (PMC). Two types of PMCs were evaluated using lap shear strength (LSS) testing, on porcine skin: a calcium metasilicate (CS1), and alpha tricalcium phosphate (αTCP) PMC. CS1 PCM bonded strongly to skin, reaching a peak LSS of 84, 132, and 154 KPa after curing for 0.5, 1.5, and 4 h, respectively. Cyanoacrylate and fibrin glues reached an LSS of 207 kPa and 33 kPa, respectively. αTCP PMCs reached a final LSS of ≈110 kPa. In soft tissues, stronger bond strengths were obtained with αTCP PMCs containing large amounts of amino acid (70-90 mol%), in contrast to prior studies in calcified tissues (30-50 mol%). When αTCP particle size was reduced by wet milling, and for CS1 PMCs, the strongest bonding was obtained with mole ratios of 30-50% phosphoserine. While PM-CPCs behave like stiff ceramics after setting, they bond to soft tissues, and warrant further investigation as tissue adhesives, particularly at the interface between hard and soft tissues.
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Affiliation(s)
- Xiuwen Li
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Michael Pujari-Palmer
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - David Wenner
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Philip Procter
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden
| | - Gerard Insley
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden
- GPBio Ltd., Unit 4D, Western Business Park, Shannon, V14 RW92 Co. Clare, Ireland
| | - Håkan Engqvist
- Applied Material Science, Department of Engineering, Uppsala University, 75121 Uppsala, Sweden.
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12
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Sroga GE, Vashishth D. Phosphorylation of Extracellular Bone Matrix Proteins and Its Contribution to Bone Fragility. J Bone Miner Res 2018; 33:2214-2229. [PMID: 30001467 DOI: 10.1002/jbmr.3552] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 07/05/2018] [Accepted: 07/08/2018] [Indexed: 01/22/2023]
Abstract
Phosphorylation of bone matrix proteins is of fundamental importance to all vertebrates including humans. However, it is currently unknown whether increase or decline of total protein phosphorylation levels, particularly in hypophosphatemia-related osteoporosis, osteomalacia, and rickets, contribute to bone fracture. To address this gap, we combined biochemical measurements with mechanical evaluation of bone to discern fracture characteristics associated with age-related development of skeletal fragility in relation to total phosphorylation levels of bone matrix proteins and one of the key representatives of bone matrix phosphoproteins, osteopontin (OPN). Here for the first time, we report that as people age the total phosphorylation level declines by approximately 20% for bone matrix proteins and approximately 30% for OPN in the ninth decade of human life. Moreover, our results suggest that the decline of total protein phosphorylation of extracellular matrix (ECM) contributes to bone fragility, but less pronouncedly than glycation. We theorize that the separation of two sources of OPN negative charges, acidic backbone amino acids and phosphorylation, would be nature's means of assuring that OPN functions in both energy dissipation and biomineralization. We propose that total phosphorylation decline could be an important contributor to the development of osteoporosis, increased fracture risk and skeletal fragility. Targeting the enzymes kinase FamC20 and bone alkaline phosphatase involved in the regulation of matrix proteins' phosphorylation could be a means for the development of suitable therapeutic treatments. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Grażyna E Sroga
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Deepak Vashishth
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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13
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Biswas S, Leitao S, Theillaud Q, Erickson BW, Fantner GE. Reducing uncertainties in energy dissipation measurements in atomic force spectroscopy of molecular networks and cell-adhesion studies. Sci Rep 2018; 8:9390. [PMID: 29925929 PMCID: PMC6010446 DOI: 10.1038/s41598-018-26979-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/23/2018] [Indexed: 11/28/2022] Open
Abstract
Atomic force microscope (AFM) based single molecule force spectroscopy (SMFS) is a valuable tool in biophysics to investigate the ligand-receptor interactions, cell adhesion and cell mechanics. However, the force spectroscopy data analysis needs to be done carefully to extract the required quantitative parameters correctly. Especially the large number of molecules, commonly involved in complex networks formation; leads to very complicated force spectroscopy curves. One therefore, generally characterizes the total dissipated energy over a whole pulling cycle, as it is difficult to decompose the complex force curves into individual single molecule events. However, calculating the energy dissipation directly from the transformed force spectroscopy curves can lead to a significant over-estimation of the dissipated energy during a pulling experiment. The over-estimation of dissipated energy arises from the finite stiffness of the cantilever used for AFM based SMFS. Although this error can be significant, it is generally not compensated for. This can lead to significant misinterpretation of the energy dissipation (up to the order of 30%). In this paper, we show how in complex SMFS the excess dissipated energy caused by the stiffness of the cantilever can be identified and corrected using a high throughput algorithm. This algorithm is then applied to experimental results from molecular networks and cell-adhesion measurements to quantify the improvement in the estimation of the total energy dissipation.
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Affiliation(s)
- Soma Biswas
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015, Lausanne, Switzerland
| | - Samuel Leitao
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015, Lausanne, Switzerland
| | - Quentin Theillaud
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015, Lausanne, Switzerland
| | - Blake W Erickson
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015, Lausanne, Switzerland
| | - Georg E Fantner
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015, Lausanne, Switzerland.
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14
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Lai ZB, Bai R, Lei Z, Yan C. Interfacial mechanical behaviour of protein–mineral nanocomposites: A molecular dynamics investigation. J Biomech 2018; 73:161-167. [DOI: 10.1016/j.jbiomech.2018.03.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/02/2018] [Accepted: 03/24/2018] [Indexed: 01/04/2023]
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15
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Lipner J, Boyle JJ, Xia Y, Birman V, Genin GM, Thomopoulos S. Toughening of fibrous scaffolds by mobile mineral deposits. Acta Biomater 2017; 58:492-501. [PMID: 28532898 DOI: 10.1016/j.actbio.2017.05.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/10/2017] [Accepted: 05/15/2017] [Indexed: 10/19/2022]
Abstract
Partially mineralized fibrous tissue situated between tendon and bone is believed to be tougher than either tendon or bone, possibly serving as a compliant, energy absorptive, protective barrier between the two. This tissue does not reform following surgical repair (e.g., rotator cuff tendon-to-bone re-attachment) and might be a factor in the poor outcomes following such surgeries. Towards our long-term goal of tissue engineered solutions to functional tendon-to-bone re-attachment, we tested the hypotheses that partially mineralized fibrous matrices can derive toughness from mobility of mineral along their fibers, and that in such cases toughness is maximized at levels of mineralization sufficiently low to allow substantial mobility. Nanofibrous electrospun poly(lactic-co-glycolic acid) (PLGA) scaffolds mineralized for prescribed times were fabricated as model systems to test these hypotheses. Tensile tests performed at varying angles relative to the dominant fiber direction confirmed that mineral cross-linked PLGA nanofibers without adhering to them. Peel tests revealed that fracture toughness increased with mineralization time up to a peak value, then subsequently decreased with increasing mineralization time back to the baseline toughness of unmineralized scaffolds. These experimental results were predicted by a theoretical model combining mineral growth kinetics with fracture energetics, suggesting that toughness increased with mineralization time until mineral mobility was attenuated by steric hindrance, then returned to baseline levels following the rigid percolation threshold. Results supported our hypotheses, and motivate further study of the roles of mobile mineral particles in toughening the tendon-to-bone attachment. STATEMENT OF SIGNIFICANCE Effective surgical repair of interfaces between tendon and bone remains an unmet clinical need, in part due to a lack of understanding of how toughness is achieved in the healthy tissue. Using combined synthesis, experiment, and modeling approaches, the current work supported the hypothesis that toughening of a fibrous scaffold arises from brittle mineral particles that crosslink the fibers, but only if the particles are free to slide relative to the fibers. In the case of the tendon-to-bone interface, this suggests that partially mineralized tissue between tendon and bone, with mobile mineral but relatively low stiffness, may serve as a compliant, energy-absorbing barrier that guards against injury. These results suggest an opportunity for fabrication of tough and strong fibrous scaffolds for tissue engineering applications.
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16
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Lai ZB, Yan C. Mechanical behaviour of staggered array of mineralised collagen fibrils in protein matrix: Effects of fibril dimensions and failure energy in protein matrix. J Mech Behav Biomed Mater 2017; 65:236-247. [DOI: 10.1016/j.jmbbm.2016.08.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 08/03/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022]
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17
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Nanoscopic characterization of the water vapor-salt interfacial layer reveals a unique biphasic adsorption process. Sci Rep 2016; 6:31688. [PMID: 27527905 PMCID: PMC4985642 DOI: 10.1038/srep31688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 07/25/2016] [Indexed: 11/09/2022] Open
Abstract
Our quantitative understanding of water adsorption onto salt surfaces under ambient conditions is presently quite poor owing to the difficulties in directly characterizing this interfacial layer under these conditions. Here we determine the thickness of the interfacial layer on NaCl at different relative humidities (RH) based on a novel application of atomic force spectroscopy and capillary condensation theory. In particular, we take advantage of the microsecond-timescale of the capillary condensation process to directly resolve the magnitude of its contribution in the tip-sample interaction, from which the interfacial water thickness is determined. Further, to correlate this thickness with salt dissolution, we also measure surface conductance under similar conditions. We find that below 30% RH, there is essentially only the deposition of water molecules onto this surface, typical of conventional adsorption onto solid surfaces. However, above 30% RH, adsorption is simultaneous with the dissolution of ions, unlike conventional adsorption, leading to a rapid increase of surface conductance. Thus, water adsorption on NaCl is an unconventional biphasic process in which the interfacial layer not only exhibits quantitative differences in thickness but also qualitative differences in composition.
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18
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Langdon A, Grohe B. The osteopontin-controlled switching of calcium oxalate monohydrate morphologies in artificial urine provides insights into the formation of papillary kidney stones. Colloids Surf B Biointerfaces 2016; 146:296-306. [PMID: 27362921 DOI: 10.1016/j.colsurfb.2016.06.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 11/30/2022]
Abstract
The protein osteopontin (OPN) plays an important role in preventing the formation of calcium oxalate monohydrate (COM) kidney stones. To gain insight into these mechanisms, crystallization was induced by addition of human kidney OPN to artificial urine (ionic strength comparable to urine; without citrate), and the OPN-COM interaction studied using a combination of scanning electron (SEM) and confocal microscopy. By SEM, we found that increasing OPN concentrations formed large monoclinic penetration twins (no protein added) and, at higher concentrations (1-, 2μg/ml OPN), super and hyper twins with crystal habits not found in previous studies. For instance, the hyper twins indicate well-facetted gearwheel-like habits with "teeth" developed in all crystallographic <h0l> directions. At OPN concentrations ≥2μg/ml, a switching to small dumbbell-shaped COM habits with fine-textured surfaces occurred. Confocal microscopy of these dumbbells indicates protein incorporation in almost the entire crystal structure (in contrast to facetted COM), proposing a threshold concentration of ∼2μg/ml OPN for the facetted to the non-facetted habit transformation. Both the gearwheel-like and the dumbbell-shaped habit are again found side-by-side (presumably triggered by OPN concentration gradients within the sample) in in-vitro formed conglomerates, which resemble cross-sections of papillary kidney stones. The abrupt transformation from facetted to non-facetted habits and the unique compliance of the two in-vitro formed habits with the two main morphologies found in papillary kidney stones propose that OPN is a main effector in direct stone-forming processes. Moreover, stone structures which exhibit these two morphologies side-by-side might serve as a novel indicator for OPN concentrations surrounding those structures.
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Affiliation(s)
- Aaron Langdon
- Schulich School of Medicine & Dentistry, School of Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada, Canada.
| | - Bernd Grohe
- Schulich School of Medicine & Dentistry, School of Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada, Canada; Department of Chemical & Biochemical Engineering, University of Western Ontario, London, ON N6A 5B9, Canada, Canada.
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19
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Bishop N. Bone Material Properties in Osteogenesis Imperfecta. J Bone Miner Res 2016; 31:699-708. [PMID: 26987995 DOI: 10.1002/jbmr.2835] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 12/29/2022]
Abstract
Osteogenesis imperfecta entrains changes at every level in bone tissue, from the disorganization of the collagen molecules and mineral platelets within and between collagen fibrils to the macroarchitecture of the whole skeleton. Investigations using an array of sophisticated instruments at multiple scale levels have now determined many aspects of the effect of the disease on the material properties of bone tissue. The brittle nature of bone in osteogenesis imperfecta reflects both increased bone mineralization density-the quantity of mineral in relation to the quantity of matrix within a specific bone volume-and altered matrix-matrix and matrix mineral interactions. Contributions to fracture resistance at multiple scale lengths are discussed, comparing normal and brittle bone. Integrating the available information provides both a better understanding of the effect of current approaches to treatment-largely improved architecture and possibly some macroscale toughening-and indicates potential opportunities for alternative strategies that can influence fracture resistance at longer-length scales.
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Affiliation(s)
- Nick Bishop
- University of Sheffield and Sheffield Children's NHS Foundation Trust, Sheffield, UK
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20
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Abstract
The interface between collagen and the mineral reinforcement phase, carbonated hydroxyapatite (cAp), is essential for bone's remarkable functionality as a biological composite material. The very small dimensions of the cAp phase and the disparate natures of the reinforcement and matrix are essential to the material's performance but also complicate study of this interface. This article summarizes what is known about the cAp-collagen interface in bone and begins with descriptions of the matrix and reinforcement roles in composites, of the phases bounding the interface, of growth of cAp growing within the collagen matrix, and of the effect of intra- and extrafibrilar mineral on determinations of interfacial properties. Different observed interfacial interactions with cAp (collagen, water, non-collagenous proteins) are reviewed; experimental results on interface interactions during loading are reported as are their influence on macroscopic mechanical properties; conclusions of numerical modeling of interfacial interactions are also presented. The data suggest interfacial interlocking (bending of collagen molecules around cAp nanoplatelets) and water-mediated bonding between collagen and cAp are essential to load transfer. The review concludes with descriptions of areas where new research is needed to improve understanding of how the interface functions.
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Affiliation(s)
- S R Stock
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611-3008, USA,
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21
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Utzig T, Raman S, Valtiner M. Scaling from single molecule to macroscopic adhesion at polymer/metal interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2722-2729. [PMID: 25668596 DOI: 10.1021/la504542f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Understanding the evolution of macroscopic adhesion based on fundamental molecular interactions is crucial to designing strong and smart polymer/metal interfaces that play an important role in many industrial and biomedical applications. Here we show how macroscopic adhesion can be predicted on the basis of single molecular interactions. In particular, we carry out dynamic single molecule-force spectroscopy (SM-AFM) in the framework of Bell-Evans' theory to gain information about the energy barrier between the bound and unbound states of an amine/gold junction. Furthermore, we use Jarzynski's equality to obtain the equilibrium ground-state energy difference of the amine/gold bond from these nonequilibrium force measurements. In addition, we perform surface forces apparatus (SFA) experiments to measure macroscopic adhesion forces at contacts where approximately 10(7) amine/gold bonds are formed simultaneously. The SFA approach provides an amine/gold interaction energy (normalized by the number of interacting molecules) of (36 ± 1)k(B)T, which is in excellent agreement with the interaction free energy of (35 ± 3)k(B)T calculated using Jarzynski's equality and single-molecule AFM experiments. Our results validate Jarzynski's equality for the field of polymer/metal interactions by measuring both sides of the equation. Furthermore, the comparison of SFA and AFM shows how macroscopic interaction energies can be predicted on the basis of single molecular interactions, providing a new strategy to potentially predict adhesive properties of novel glues or coatings as well as bio- and wet adhesion.
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Affiliation(s)
- Thomas Utzig
- Department of Interface Chemistry and Surface Engineering, Max-Planck-Institut für Eisenforschung GmbH , Max-Planck Straße 1, 40237 Düsseldorf, Germany
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22
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Abstract
The ability of bone to resist fracture is determined by the combination of bone mass and bone quality. Like bone mass, bone quality is carefully regulated. Of the many aspects of bone quality, this review focuses on biological mechanisms that control the material quality of the bone extracellular matrix (ECM). Bone ECM quality depends upon ECM composition and organization. Proteins and signaling pathways that affect the mineral or organic constituents of bone ECM impact bone ECM material properties, such as elastic modulus and hardness. These properties are also sensitive to pathways that regulate bone remodeling by osteoblasts, osteoclasts, and osteocytes. Several extracellular proteins, signaling pathways, intracellular effectors, and transcription regulatory networks have been implicated in the control of bone ECM quality. A molecular understanding of these mechanisms will elucidate the biological control of bone quality and suggest new targets for the development of therapies to prevent bone fragility.
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Affiliation(s)
- Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, 513 Parnassus Avenue, Room S-1155, San Francisco, CA, 94143-0514, USA,
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23
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Makowski AJ, Uppuganti S, Wadeer SA, Whitehead JM, Rowland BJ, Granke M, Mahadevan-Jansen A, Yang X, Nyman JS. The loss of activating transcription factor 4 (ATF4) reduces bone toughness and fracture toughness. Bone 2014; 62:1-9. [PMID: 24509412 PMCID: PMC3992706 DOI: 10.1016/j.bone.2014.01.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 01/06/2014] [Accepted: 01/28/2014] [Indexed: 01/10/2023]
Abstract
Even though age-related changes to bone tissue affecting fracture risk are well characterized, only a few matrix-related factors have been identified as important to maintaining fracture resistance. As a gene critical to osteoblast differentiation, activating transcription factor 4 (ATF4) is possibly one of these important factors. To test the hypothesis that the loss of ATF4 affects the fracture resistance of bone beyond bone mass and structure, we harvested bones from Atf4+/+ and Atf4-/- littermates at 8 and 20 weeks of age (n≥9 per group) for bone assessment across several length scales. From whole bone mechanical tests in bending, femurs from Atf4-/- mice were found to be brittle with reduced toughness and fracture toughness compared to femurs from Atf4+/+ mice. However, there were no differences in material strength and in tissue hardness, as determined by nanoindentation, between the genotypes, irrespective of age. Tissue mineral density of the cortex at the point of loading as determined by micro-computed tomography was also not significantly different. However, by analyzing local composition by Raman Spectroscopy (RS), bone tissue of Atf4-/- mice was found to have higher mineral to collagen ratio compared to wild-type tissue, primarily at 20 weeks of age. From RS analysis of intact femurs at 2 orthogonal orientations relative to the polarization axis of the laser, we also found that the organizational-sensitive peak ratio, ν1Phosphate per Amide I, changed to a greater extent upon bone rotation for Atf4-deficient tissue, implying bone matrix organization may contribute to the brittleness phenotype. Target genes of ATF4 activity are not only important to osteoblast differentiation but also in maintaining bone toughness and fracture toughness.
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Affiliation(s)
- Alexander J Makowski
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 27212, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Sasidhar Uppuganti
- Department of Orthopaedic Surgery & Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sandra A Wadeer
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 27212, USA
| | - Jack M Whitehead
- Department of Orthopaedic Surgery & Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Barbara J Rowland
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 27212, USA; Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Mathilde Granke
- Department of Orthopaedic Surgery & Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Xiangli Yang
- Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jeffry S Nyman
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 27212, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA; Department of Orthopaedic Surgery & Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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24
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Lai ZB, Wang M, Yan C, Oloyede A. Molecular dynamics simulation of mechanical behavior of osteopontin-hydroxyapatite interfaces. J Mech Behav Biomed Mater 2014; 36:12-20. [PMID: 24786380 DOI: 10.1016/j.jmbbm.2014.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/03/2014] [Accepted: 04/05/2014] [Indexed: 10/25/2022]
Abstract
Bone is characterized with an optimized combination of high stiffness and toughness. The understanding of bone nanomechanics is critical to the development of new artificial biological materials with unique properties. In this work, the mechanical characteristics of the interfaces between osteopontin (OPN, a noncollagenous protein in extrafibrillar protein matrix) and hydroxyapatite (HA, a mineral nanoplatelet in mineralized collagen fibrils) were investigated using molecular dynamics method. We found that the interfacial mechanical behavior is governed by the electrostatic attraction between acidic amino acid residues in OPN and calcium in HA. Higher energy dissipation is associated with the OPN peptides with a higher number of acidic amino acid residues. When loading in the interface direction, new bonds between some acidic residues and HA surface are formed, resulting in a stick-slip type motion of OPN peptide on the HA surface and high interfacial energy dissipation. The formation of new bonds during loading is considered to be a key mechanism responsible for high fracture resistance observed in bone and other biological materials.
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Affiliation(s)
- Zheng Bo Lai
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia
| | - Mingchao Wang
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia
| | - Cheng Yan
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia.
| | - Adekunle Oloyede
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia
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25
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Heredia A, Colin-Garcia M, Peña-Rico MA, Beltrán LFLA, Grácio J, Contreras-Torres FF, Rodríguez-Galván A, Bucio L, Basiuk VA. Thermal, infrared spectroscopy and molecular modeling characterization of bone: An insight in the apatite-collagen type I interaction. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/abc.2013.32027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Direct Measurements of the Cohesive Behavior of Soft Biological Interfaces. MECHANICS OF BIOLOGICAL SYSTEMS AND MATERIALS, VOLUME 5 2013. [DOI: 10.1007/978-1-4614-4427-5_29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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27
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Load-bearing in cortical bone microstructure: Selective stiffening and heterogeneous strain distribution at the lamellar level. J Mech Behav Biomed Mater 2013; 17:152-65. [DOI: 10.1016/j.jmbbm.2012.08.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 12/25/2022]
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28
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Katsamenis OL, Karoutsos V, Kontostanos K, Panagiotopoulos EC, Papadaki H, Bouropoulos N. Microstructural characterization of CPPD and hydroxyapatite crystal depositions on human menisci. CRYSTAL RESEARCH AND TECHNOLOGY 2012. [DOI: 10.1002/crat.201200346] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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29
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Dastjerdi AK, Pagano M, Kaartinen MT, McKee MD, Barthelat F. Cohesive behavior of soft biological adhesives: experiments and modeling. Acta Biomater 2012; 8:3349-59. [PMID: 22588071 DOI: 10.1016/j.actbio.2012.05.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/18/2012] [Accepted: 05/08/2012] [Indexed: 01/26/2023]
Abstract
Extracellular proteins play a key role in generating and maintaining cohesion and adhesion in biological tissues. These "natural glues" are involved in vital biological processes such as blood clotting, wound healing and maintaining the structural integrity of tissues. Macromolecular assemblies of proteins can be functionally stabilized in a variety of ways in situ that include ionic interactions as well as covalent crosslinking to form protein networks that can extend both within and between tissues. Within tissues, myriad cohesive forces are required to preserve tissue integrity and function, as are additional appropriate adhesive forces at interfaces both within and between tissues of differing composition. While the mechanics of some key structural adhesive proteins have been characterized in tensile experiments at both the macroscopic and single protein levels, the fracture toughness of thin proteinaceous interfaces has never been directly measured. Here, we describe a novel and simple approach to measure the cohesive behavior and toughness of thin layers of proteinaceous adhesives. The test is based on the standard double-cantilever beam test used for engineering adhesives, which was adapted to take into account the high compliance of the interface compared with the beams. This new "rigid double-cantilever beam" method enables stable crack propagation through an interfacial protein layer, and provides a direct way to measure its full traction-separation curve. The method does not require any assumption of the shape of the cohesive law, and the results provide abundant information contributing to understanding the structural, chemical and molecular mechanisms acting in biological adhesion. As an example, results are presented using this method for thin films of fibrin-a protein involved in blood clotting and used clinically as a tissue bio-adhesive after surgery-with the effects of calcium and crosslinking by Factor XIII being examined. Finally, a simple model is proposed, demonstrating how a bell-shaped cohesive law forms during the failure of the fibrin interface based on an eight-chain model whose structure degrades and changes configuration with stress.
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Affiliation(s)
- A Khayer Dastjerdi
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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30
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Kalmar L, Homola D, Varga G, Tompa P. Structural disorder in proteins brings order to crystal growth in biomineralization. Bone 2012; 51:528-34. [PMID: 22634174 DOI: 10.1016/j.bone.2012.05.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 04/17/2012] [Accepted: 05/16/2012] [Indexed: 11/21/2022]
Abstract
Biomineralization, the generation of hard tissues of living organisms, is a process strictly regulated by hormones, enzymes and a range of regulatory proteins of which several resisted structural characterization thus far. Without actual generalizations, there have been scattered observations in the literature for the structural disorder of these proteins. To address this issue in general, we have collected SwissProt proteins involved in the formation of bone and teeth in vertebrates, annotated for biomineralization. All these proteins show an extremely high level of predicted disorder (with a mean of 53%), making them the most disordered functional class of the protein world. Exactly the same feature was established for evolutionarily more distant proteins involved in the formation of the silica wall of marine diatoms and the shell of oysters and other mollusks. Because these proteins also show an extremely biased amino acid composition, such as high negative charge, high frequency of Ser and Asp or Pro residues and repetitiveness, we also carried out a database search with these sequence features for further proteins. This search uncovered several further disordered proteins with clearly related functions, although their annotations made no mention of biomineralization. This general and very strong correlation between biomineralization, structural disorder of proteins and particular sequence features indicates that regulated growth of mineral phase in biology can only be achieved by the assistance of highly disordered proteins.
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Affiliation(s)
- Lajos Kalmar
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, Hungary
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31
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Raghavan M, Sahar ND, Kohn DH, Morris MD. Age-specific profiles of tissue-level composition and mechanical properties in murine cortical bone. Bone 2012; 50:942-53. [PMID: 22285889 PMCID: PMC3299845 DOI: 10.1016/j.bone.2011.12.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 01/22/2023]
Abstract
There is growing evidence that bone composition and tissue-level mechanical properties are significant determinants of skeletal integrity. In the current study, Raman spectroscopy and nanoindentation testing were co-localized to analyze tissue-level compositional and mechanical properties in skeletally mature young (4 or 5 months) and old (19 months) murine femora at similar spatial scales. Standard multivariate linear regression analysis revealed age-dependent patterns in the relationships between mechanical and compositional properties at the tissue scale. However, changes in bone material properties with age are often complex and nonlinear, and can be missed with linear regression and correlation-based methods. A retrospective data mining approach was implemented using non-linear multidimensional visualization and classification to identify spectroscopic and nanoindentation metrics that best discriminated bone specimens of different age-classes. The ability to classify the specimens into the correct age group increased by using combinations of Raman and nanoindentation variables (86-96% accuracy) as compared to using individual measures (59-79% accuracy). Metrics that best classified 4 or 5 month and 19 month specimens (2-age classes) were mineral to matrix ratio, crystallinity, modulus and plasticity index. Metrics that best distinguished between 4, 5 and 19 month specimens (3-age classes) were mineral to matrix ratio, crystallinity, modulus, hardness, cross-linking, carbonate to phosphate ratio, creep displacement and creep viscosity. These findings attest to the complexity of mechanisms underlying bone tissue properties and draw attention to the importance of considering non-linear interactions between tissue-level composition and mechanics that may work together to influence material properties with age. The results demonstrate that a few non-linearly combined compositional and mechanical metrics provide better discriminatory information than a single metric or a single technique.
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Affiliation(s)
| | | | - David H. Kohn
- Department of Biomedical Engineering, Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
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Chan SMT, Neu CP, Komvopoulos K, Reddi AH. Dependence of nanoscale friction and adhesion properties of articular cartilage on contact load. J Biomech 2011; 44:1340-5. [PMID: 21316681 DOI: 10.1016/j.jbiomech.2011.01.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 01/05/2011] [Accepted: 01/05/2011] [Indexed: 11/28/2022]
Abstract
Boundary lubrication of articular cartilage by conformal, molecularly thin films reduces friction and adhesion between asperities at the cartilage-cartilage contact interface when the contact conditions are not conducive to fluid film lubrication. In this study, the nanoscale friction and adhesion properties of articular cartilage from typical load-bearing and non-load-bearing joint regions were studied in the boundary lubrication regime under a range of physiological contact pressures using an atomic force microscope (AFM). Adhesion of load-bearing cartilage was found to be much lower than that of non-load-bearing cartilage. In addition, load-bearing cartilage demonstrated steady and low friction coefficient through the entire load range examined, whereas non-load-bearing cartilage showed higher friction coefficient that decreased nonlinearly with increasing normal load. AFM imaging and roughness calculations indicated that the above trends in the nanotribological properties of cartilage are not due to topographical (roughness) differences. However, immunohistochemistry revealed consistently higher surface concentration of boundary lubricant at load-bearing joint regions. The results of this study suggest that under contact conditions leading to joint starvation from fluid lubrication, the higher content of boundary lubricant at load-bearing cartilage sites preserves synovial joint function by minimizing adhesion and wear at asperity microcontacts, which are precursors for tissue degeneration.
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Affiliation(s)
- S M T Chan
- Center for Tissue Regeneration and Repair, University of California, Davis, Medical Center, Sacramento, CA 95817, USA
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Cooperation of phosphates and carboxylates controls calcium oxalate crystallization in ultrafiltered urine. ACTA ACUST UNITED AC 2011; 39:327-38. [PMID: 21234554 DOI: 10.1007/s00240-010-0360-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 12/30/2010] [Indexed: 10/18/2022]
Abstract
Osteopontin (OPN) is one of a group of proteins found in urine that are believed to limit the formation of kidney stones. In the present study, we investigate the roles of phosphate and carboxylate groups in the OPN-mediated modulation of calcium oxalate (CaOx), the principal mineral phase found in kidney stones. To this end, crystallization was induced by addition of CaOx solution to ultrafiltered human urine containing either human kidney OPN (kOPN; 7 consecutive carboxylates, 8 phosphates) or synthesized peptides corresponding to residues 65-80 (pSHDHMDDDDDDDDDGD; pOPAR) or 220-235 (pSHEpSTEQSDAIDpSAEK; P3) of rat bone OPN. Sequence 65-80 was also synthesized without the phosphate group (OPAR). Effects on calcium oxalate monohydrate (COM) and dihydrate (COD) formation were studied by scanning electron microscopy. We found that controls form large, partly intergrown COM platelets; COD was never observed. Adding any of the polyelectrolytes was sufficient to prevent intergrowth of COM platelets entirely, inhibiting formation of these platelets strongly, and inducing formation of the COD phase. Strongest effects on COM formation were found for pOPAR and OPAR followed by kOPN and then P3, showing that acidity and hydrophilicity are crucial in polyelectrolyte-affected COM crystallization. At higher concentrations, OPAR also inhibited COD formation, while P3, kOPN and, in particular, pOPAR promoted COD, a difference explainable by the variations of carboxylate and phosphate groups present in the molecules. Thus, we conclude that carboxylate groups play a primary role in inhibiting COM formation, but phosphate and carboxylate groups are both important in initiating and promoting COD formation.
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Thurner PJ, Chen CG, Ionova-Martin S, Sun L, Harman A, Porter A, Ager JW, Ritchie RO, Alliston T. Osteopontin deficiency increases bone fragility but preserves bone mass. Bone 2010; 46:1564-73. [PMID: 20171304 PMCID: PMC2875278 DOI: 10.1016/j.bone.2010.02.014] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 12/17/2022]
Abstract
The ability of bone to resist catastrophic failure is critically dependent upon the material properties of bone matrix, a composite of hydroxyapatite, collagen type I, and noncollagenous proteins. These properties include elastic modulus, hardness, and fracture toughness. Like other aspects of bone quality, matrix material properties are biologically-defined and can be disrupted in skeletal disease. While mineral and collagen have been investigated in greater detail, the contribution of noncollagenous proteins such as osteopontin to bone matrix material properties remains unclear. Several roles have been ascribed to osteopontin in bone, many of which have the potential to impact material properties. To elucidate the role of osteopontin in bone quality, we evaluated the structure, composition, and material properties of bone from osteopontin-deficient mice and wild-type littermates at several length scales. Most importantly, the results show that osteopontin deficiency causes a 30% decrease in fracture toughness, suggesting an important role for OPN in preventing crack propagation. This significant decline in fracture toughness is independent of changes in whole bone mass, structure, or matrix porosity. Using nanoindentation and quantitative backscattered electron imaging to evaluate osteopontin-deficient bone matrix at the micrometer level, we observed a significant reduction in elastic modulus and increased variability in calcium concentration. Matrix heterogeneity was also apparent at the ultrastructural level. In conclusion, we find that osteopontin is essential for the fracture toughness of bone, and reduced toughness in osteopontin-deficient bone may be related to the increased matrix heterogeneity observed at the micro-scale. By exploring the effects of osteopontin deficiency on bone matrix material properties, composition and organization, this study suggests that reduced fracture toughness is one mechanism by which loss of noncollagenous proteins contribute to bone fragility.
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Affiliation(s)
- Philipp J. Thurner
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
- School of Engineering Sciences, University of Southampton, UK
| | - Carol G. Chen
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
| | - Sophi Ionova-Martin
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Luling Sun
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | | | | | - Joel W. Ager
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Robert O. Ritchie
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, Department of Otolaryngology, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California San Francisco, CA, USA
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35
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McNamara LM. Perspective on post-menopausal osteoporosis: establishing an interdisciplinary understanding of the sequence of events from the molecular level to whole bone fractures. J R Soc Interface 2010; 7:353-72. [PMID: 19846441 PMCID: PMC2842799 DOI: 10.1098/rsif.2009.0282] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 09/30/2009] [Indexed: 11/12/2022] Open
Abstract
Current drug treatments for post-menopausal osteoporosis cannot eliminate bone fractures, possibly because the mechanisms responsible for bone loss are not fully understood. Although research within various disciplines has significantly advanced the state of knowledge, fundamental findings are not widely understood between different disciplines. For that reason, this paper presents noteworthy experimental findings from discrete disciplines focusing on post-menopausal osteoporosis. These studies have established that, in addition to bone loss, significant changes in bone micro-architecture, tissue composition and micro-damage occur. Cellular processes and molecular signalling pathways governing pathological bone resorption have been identified to a certain extent. Ongoing studies endeavour to determine how such changes are initiated at the onset of oestrogen deficiency. It emerges that, because of the discrete nature of previous research studies, the sequence of events that lead to bone fracture is not fully understood. In this paper, two sequences of multi-scale changes are proposed and the experimental challenges that need to be overcome to fully define this sequence are outlined. Future studies must comprehensively characterize the time sequence of molecular-, cellular- and tissue-level changes to attain a coherent understanding of the events that ultimately lead to bone fracture and inform the future development of treatments for post-menopausal osteoporosis.
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Affiliation(s)
- L M McNamara
- Department of Mechanical and Biomedical Engineering, National University of Ireland Galway, Galway, Ireland.
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36
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Thurner PJ. Atomic force microscopy and indentation force measurement of bone. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2009; 1:624-49. [DOI: 10.1002/wnan.56] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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