1
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Biswal S, Agmon N. Collagen Structured Hydration. Biomolecules 2023; 13:1744. [PMID: 38136615 PMCID: PMC10742079 DOI: 10.3390/biom13121744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023] Open
Abstract
Collagen is a triple-helical protein unique to the extracellular matrix, conferring rigidity and stability to tissues such as bone and tendon. For the [(PPG)10]3 collagen-mimetic peptide at room temperature, our molecular dynamics simulations show that these properties result in a remarkably ordered first hydration layer of water molecules hydrogen bonded to the backbone carbonyl (bb-CO) oxygen atoms. This originates from the following observations. The radius of gyration attests that the PPG triplets are organized along a straight line, so that all triplets (excepting the ends) are equivalent. The solvent-accessible surface area (SASA) for the bb-CO oxygens shows a repetitive regularity for every triplet. This leads to water occupancy of the bb-CO sites following a similar regularity. In the crystal-phase X-ray data, as well as in our 100 K simulations, we observe a 0-2-1 water occupancy in the P-P-G triplet. Surprisingly, a similar (0-1.7-1) regularity is maintained in the liquid phase, in spite of the sub-nsec water exchange rates, because the bb-CO sites rarely remain vacant. The manifested ordered first-shell water molecules are expected to produce a cylindrical electrostatic potential around the peptide, to be investigated in future work.
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Affiliation(s)
| | - Noam Agmon
- The Fritz Haber Research Center, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
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2
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Momot KI. Hydrated Collagen: Where Physical Chemistry, Medical Imaging, and Bioengineering Meet. J Phys Chem B 2022; 126:10305-10316. [PMID: 36473185 DOI: 10.1021/acs.jpcb.2c06217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It is well-known that collagen is the most abundant protein in the human body; however, what is not often appreciated is its fascinating physical chemistry and molecular physics. In this Perspective, we aim to expose some of the physicochemical phenomena associated with the hydration of collagen and to examine the role collagen's hydration water plays in determining its biological function as well as applications ranging from radiology to bioengineering. The main focus is on the Magic-Angle Effect, a phenomenon observed in Nuclear Magnetic Resonance (NMR) spectroscopy and Magnetic Resonance Imaging (MRI) of anisotropic collagenous tissues such as articular cartilage and tendon. While the effect has been known in NMR and MRI for decades, its exact molecular mechanism remains a topic of debate and continuing research in scientific literature. We survey some of the latest research aiming to develop a comprehensive molecular-level model of the Magic-Angle Effect. We also touch on other fields where understanding of collagen hydration is important, particularly nanomechanics and mechanobiology, biomaterials, and piezoelectric sensors.
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Affiliation(s)
- Konstantin I Momot
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia
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3
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Bełdowski P, Przybyłek M, Bełdowski D, Dedinaite A, Sionkowska A, Cysewski P, Claesson PM. Collagen type II-hyaluronan interactions - the effect of proline hydroxylation: a molecular dynamics study. J Mater Chem B 2022; 10:9713-9723. [PMID: 36413305 DOI: 10.1039/d2tb01550a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hyaluronan-collagen composites have been employed in numerous biomedical applications. Understanding the interactions between hyaluronan and collagen is particularly important in the context of joint cartilage function and the treatment of joint diseases. Many factors affect the affinity of collagen for hyaluronan. One of the important factors is the ratio of 3- or 4-hydroxy proline to proline residues. This article presents the results from molecular dynamics calculations of HA-collagen type II interactions with hyaluronan. The applied protocol employed docking and geometry optimization of complexes built using collagen structures with different numbers of hydroxyl groups attached to proline moieties. It was established that the hydroxyproline/proline ratio affects both structural and energetic features of the collagen-hyaluronan complex. Proline hydroxylation was found to significantly influence the number of all identified types of molecular forces, hydrophobic interactions, water bridges and hydrogen bonds, which can be formed between collagen and hyaluronan. Importantly, an increase in the hydroxyproline/proline ratio in the collagen chain increases the binding affinity for hyaluronan. This is illustrated by the linear correlation between the binding free energy and the hydroxylation degree. A comparison of the results obtained for 3 and 4 hydroxylation of proline indicates that the hydroxyl group attachment position plays a minor role in complex stabilization. However, a slightly stronger affinity was observed for 4 hydroxylation. In order to evaluate the effect of the aqueous environment on the collagen-hyaluronan complex stability, the enthalpic and entropic contributions to the free energy of solvation were analyzed.
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Affiliation(s)
- Piotr Bełdowski
- Institute of Mathematics and Physics, Bydgoszcz University of Science and Technology, al. Kaliskiego 7, 85-796 Bydgoszcz, Poland.
| | - Maciej Przybyłek
- Department of Physical Chemistry, Pharmacy Faculty, Collegium Medicum of Bydgoszcz, Nicolaus Copernicus University in Toruń, Kurpińskiego 5, 85-950 Bydgoszcz, Poland
| | - Damian Bełdowski
- Institute of Mathematics, Jagiellonian University, Lukasiewicza 6, 30-348 Kraków, Poland
| | - Andra Dedinaite
- Division of Surface and Corrosion Science, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.,KTH Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Engineering Pedagogics, SE-100 44 Stockholm, Sweden
| | - Alina Sionkowska
- Department of Biomaterials and Cosmetics Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarin 7, 87-100 Toruń, Poland
| | - Piotr Cysewski
- Department of Physical Chemistry, Pharmacy Faculty, Collegium Medicum of Bydgoszcz, Nicolaus Copernicus University in Toruń, Kurpińskiego 5, 85-950 Bydgoszcz, Poland
| | - Per M Claesson
- Division of Surface and Corrosion Science, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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4
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Karjalainen J, Henschel H, Nissi MJ, Nieminen MT, Hanni M. Dipolar Relaxation of Water Protons in the Vicinity of a Collagen-like Peptide. J Phys Chem B 2022; 126:2538-2551. [PMID: 35343227 PMCID: PMC8996236 DOI: 10.1021/acs.jpcb.2c00052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
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Quantitative magnetic
resonance imaging is one of the few available
methods for noninvasive diagnosis of degenerative changes in articular
cartilage. The clinical use of the imaging data is limited by the
lack of a clear association between structural changes at the molecular
level and the measured magnetic relaxation times. In anisotropic,
collagen-containing tissues, such as articular cartilage, the orientation
dependency of nuclear magnetic relaxation can obscure the content
of the images. Conversely, if the molecular origin of the phenomenon
would be better understood, it would provide opportunities for diagnostics
as well as treatment planning of degenerative changes in these tissues.
We study the magnitude and orientation dependence of the nuclear magnetic
relaxation due to dipole–dipole coupling of water protons in
anisotropic, collagenous structures. The water–collagen interactions
are modeled with molecular dynamics simulations of a small collagen-like
peptide dissolved in water. We find that in the vicinity of the collagen-like
peptide, the dipolar relaxation of water hydrogen nuclei is anisotropic,
which can result in orientation-dependent relaxation times if the
water remains close to the peptide. However, the orientation-dependency
of the relaxation is different from the commonly observed magic-angle
phenomenon in articular cartilage MRI.
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Affiliation(s)
- Jouni Karjalainen
- Research Unit of Medical Imaging Physics and Technology, University of Oulu, P.O. Box 5000, Oulu 90014, Finland
| | - Henning Henschel
- Research Unit of Medical Imaging Physics and Technology, University of Oulu, P.O. Box 5000, Oulu 90014, Finland
| | - Mikko J Nissi
- Research Unit of Medical Imaging Physics and Technology, University of Oulu, P.O. Box 5000, Oulu 90014, Finland.,Department of Applied Physics, University of Eastern Finland, Kuopio 70210, Finland
| | - Miika T Nieminen
- Research Unit of Medical Imaging Physics and Technology, University of Oulu, P.O. Box 5000, Oulu 90014, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90014, Finland.,Medical Research Center, University of Oulu and Oulu University Hospital, Oulu 90014, Finland
| | - Matti Hanni
- Research Unit of Medical Imaging Physics and Technology, University of Oulu, P.O. Box 5000, Oulu 90014, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90014, Finland.,Medical Research Center, University of Oulu and Oulu University Hospital, Oulu 90014, Finland
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5
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Hager B, Schreiner MM, Walzer SM, Hirtler L, Mlynarik V, Berg A, Deligianni X, Bieri O, Windhager R, Trattnig S, Juras V. Transverse Relaxation Anisotropy of the Achilles and Patellar Tendon Studied by MR Microscopy. J Magn Reson Imaging 2022; 56:1091-1103. [PMID: 35122454 PMCID: PMC9545006 DOI: 10.1002/jmri.28095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 01/20/2023] Open
Abstract
Background T2* anisotropy affects the clinical assessment of tendons (magic‐angle artifact) and may be a source of T2*‐misinterpretation. Purpose To analyze T2*‐anisotropy and T2*‐decay of Achilles and patellar tendons in vitro at microscopic resolution using a variable‐echo‐time (vTE) sequence. Study Type Prospective. Specimen Four human Achilles and four patellar tendons. Field Strength/Sequence A 7 T MR‐microscopy; 3D‐vTE spoiled‐gradient‐echo‐sequence (T2*‐mapping). Assessment All tendons were measured at 0° and 55° relative to B0. Additional angles were measured for one Achilles and one patellar tendon for a total of 11 angles ranging from 0° to 90°. T2*‐decay was analyzed with mono‐ and bi‐exponential signal fitting. Mono‐exponential T2*‐values (T2*m), short and long T2*‐components (T2*s, T2*l), and the fraction of the short component Fs of the bi‐exponential T2*‐fit were calculated. T2*‐decay characteristics were compared with morphological MRI and histologic findings based on a region‐of‐interest analysis. Statistical Tests Akaike information criterion (AICC), F‐test, and paired t‐test. A P value smaller than the α‐level of 0.05 was considered statistically significant. Results T2*m‐values between fiber‐to‐field angles of 0° and 55° were increased on average from T2*m (0°) = 1.92 msec to T2*m (55°) = 29.86 msec (15.5‐fold) in the Achilles and T2*m (0°) = 1.46 msec to T2*m (55°) = 23.33 msec (16.0‐fold) in the patellar tendons. The changes in T2*m‐values were statistically significant. For the whole tendon, according to F‐test and AICC, a bi‐exponential model was preferred for angles close to 0°, while the mono‐exponential model tended to be preferred at angles close to 55°. Conclusion MR‐microscopy provides a deeper insight into the relationship between T2*‐decay (mono‐ vs. bi‐exponential model) and tendon heterogeneity. Changes in fiber‐to‐field angle result in significant changes in T2*‐values. Thus, we conclude that awareness of T2*‐anisotropy should be noted in quantitative T2*‐mapping of tendons to avoid T2*‐misinterpretation such as a false positive detection of degeneration due to large fiber‐to‐field angles. Evidence Level 2 Technical Efficacy Stage 2
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Affiliation(s)
- Benedikt Hager
- Institute for Clinical Molecular MRI in the Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria
| | - Markus M Schreiner
- Department of Orthopedics and Trauma-Surgery, Medical University of Vienna, Austria
| | - Sonja M Walzer
- Department of Orthopedics and Trauma-Surgery, Medical University of Vienna, Austria
| | - Lena Hirtler
- Center for Anatomy and Cell Biology, Division of Anatomy, Medical University of Vienna, Austria
| | - Vladimir Mlynarik
- Institute for Clinical Molecular MRI in the Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria
| | - Andreas Berg
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Xeni Deligianni
- Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland.,Basel Muscle MRI, Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Reinhard Windhager
- Department of Orthopedics and Trauma-Surgery, Medical University of Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria.,CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria
| | - Vladimir Juras
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria.,CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria
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6
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Pang Y. Characterization of anisotropic T2W signals from human knee femoral cartilage: The magic angle effect on a spherical surface. NMR IN BIOMEDICINE 2021; 34:e4535. [PMID: 33963785 DOI: 10.1002/nbm.4535] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/23/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
The aim of the current study was to propose a generalized magic angle effect (gMAE) function for characterizing anisotropic T2W signals of human knee femoral cartilage with a spherical surface in clinical studies. A gMAE model function f(α, ε) was formulated for an orientation-dependent (ε) transverse T2 (i.e., 1/R2 ) relaxation in cartilage assuming an axially symmetric distribution (α) of collagen fibers. T2W sagittal images were acquired on an adult volunteer's healthy knee at 3 T, and ROI-based average signals S(ε) were extracted from angularly and radially segmented femoral cartilage. Compared with the standard MAE (sMAE) functions in the deep (DZ, α = 0°) and in the superficial (SZ, α = 90°) zones, a general form of R2 orientation-dependent function f(α, ε) was fitted to S(ε), including an isotropic R2 contribution (internal reference [REF]). Goodness of fit was evaluated by root-mean-square deviations (RMSDs). An F-test and a paired t-test were respectively used to assess significant differences between the observed variances and means, with statistical significance set to p less than .05. As a symmetric orientation-dependence function with a varying dynamic range, the proposed gMAE model outperformed the previous sMAE functions manifested by significantly reduced RMSDs in the DZ (0.239 ± 0.122 vs. 0.267 ± 0.097, p = .014) and in the SZ (0.183 ± 0.081 vs. 0.254 ± 0.085, p < .001). The fitted average angle α (38.5 ± 34.6° vs. 45.1 ± 30.1°, p < .43) and REF (5.092 ± 0.369 vs. 5.305 ± 0.440, p < .001) were smaller in the DZ than those in SZ, in good agreement with the reported collagen fibril microstructural configurations and the nonbound water contribution to R2 in articular cartilage. In conclusion, a general form of the magic angle effect function was proposed and demonstrated for better characterizing anisotropic T2W signals from human knee femoral cartilage at 3 T in clinical studies.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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7
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Milazzo M, David A, Jung GS, Danti S, Buehler MJ. Molecular origin of viscoelasticity in mineralized collagen fibrils. Biomater Sci 2021; 9:3390-3400. [PMID: 33949363 PMCID: PMC8323817 DOI: 10.1039/d0bm02003f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/01/2021] [Indexed: 11/21/2022]
Abstract
Bone is mineralized tissue constituting the skeletal system, supporting and protecting the body's organs and tissues. In addition to such fundamental mechanical functions, bone also plays a remarkable role in sound conduction. From a mechanical standpoint, bone is a composite material consisting of minerals and collagen arranged in multiple hierarchical structures, with a complex anisotropic viscoelastic response, capable of transmitting and dissipating energy. At the molecular level, mineralized collagen fibrils are the basic building blocks of bone tissue, and hence, understanding bone properties down to fundamental tissue structures enables better identification of the mechanisms of structural failures and damage. While efforts have focused on the study of micro- and macro-scale viscoelasticity related to bone damage and healing based on creep, mineralized collagen has not been explored at the molecular level. We report a study that aims at systematically exploring the viscoelasticity of collagenous fibrils with different mineralization levels. We investigate the dynamic mechanical response upon cyclic and impulsive loads to observe the viscoelastic phenomena from either shear or extensional strains via molecular dynamics. We perform a sensitivity analysis with several key benchmarks: intrafibrillar mineralization percentage, hydration state, and external load amplitude. Our results show an increase of the dynamic moduli with an increase of the mineral percentage, pronounced at low strains. When intrafibrillar water is present, the material softens the elastic component, but considerably increases its viscosity, especially at high frequencies. This behavior is confirmed from the material response upon impulsive loads, in which water drastically reduces the relaxation times throughout the input velocity range by one order of magnitude, with respect to the dehydrated counterparts. We find that, upon transient loads, water has a major impact on the mechanics of mineralized fibrillar collagen, being able to improve the capability of the tissue to passively and effectively dissipate energy, especially after fast and high-amplitude external loads. Our study provides knowledge of bone mechanics in relation to pathologies deriving from dehydration or traumas. Moreover, these findings show the potential for being used in designing new bioinspired materials not limited to tissue engineering applications, in which passive mechanisms for dissipating energy can prevent structural failures.
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Affiliation(s)
- Mario Milazzo
- Laboratory for Atomistic and Molecular Mechanics (LAMM), USA. and The BioRobotics Institute, Scuola Superiore Sant'Anna, Italy
| | - Alessio David
- Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta", Politecnico di Milano, Milano, Italy
| | - Gang Seob Jung
- Laboratory for Atomistic and Molecular Mechanics (LAMM), USA. and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Serena Danti
- Laboratory for Atomistic and Molecular Mechanics (LAMM), USA. and The BioRobotics Institute, Scuola Superiore Sant'Anna, Italy and Department of Civil and Industrial Engineering, University of Pisa, Italy
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8
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Madhavi WM, Weerasinghe S, Momot KI. Reorientational dynamics of molecules in liquid methane: A molecular dynamics simulation study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Siadat SM, Zamboulis DE, Thorpe CT, Ruberti JW, Connizzo BK. Tendon Extracellular Matrix Assembly, Maintenance and Dysregulation Throughout Life. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1348:45-103. [PMID: 34807415 DOI: 10.1007/978-3-030-80614-9_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In his Lissner Award medal lecture in 2000, Stephen Cowin asked the question: "How is a tissue built?" It is not a new question, but it remains as relevant today as it did when it was asked 20 years ago. In fact, research on the organization and development of tissue structure has been a primary focus of tendon and ligament research for over two centuries. The tendon extracellular matrix (ECM) is critical to overall tissue function; it gives the tissue its unique mechanical properties, exhibiting complex non-linear responses, viscoelasticity and flow mechanisms, excellent energy storage and fatigue resistance. This matrix also creates a unique microenvironment for resident cells, allowing cells to maintain their phenotype and translate mechanical and chemical signals into biological responses. Importantly, this architecture is constantly remodeled by local cell populations in response to changing biochemical (systemic and local disease or injury) and mechanical (exercise, disuse, and overuse) stimuli. Here, we review the current understanding of matrix remodeling throughout life, focusing on formation and assembly during the postnatal period, maintenance and homeostasis during adulthood, and changes to homeostasis in natural aging. We also discuss advances in model systems and novel tools for studying collagen and non-collagenous matrix remodeling throughout life, and finally conclude by identifying key questions that have yet to be answered.
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Affiliation(s)
| | - Danae E Zamboulis
- Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, The Royal Veterinary College, University of London, London, UK
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Brianne K Connizzo
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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10
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Hashikawa Y, Murata Y. A Single H2O Molecule inside Hydrophobic Carbon Nanocavities: Effect of Local Electrostatic Potential. CHEM LETT 2020. [DOI: 10.1246/cl.190874] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yoshifumi Hashikawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yasujiro Murata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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11
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T1- and T2*-Mapping for Assessment of Tendon Tissue Biophysical Properties: A Phantom MRI Study. Invest Radiol 2019; 54:212-220. [PMID: 30444794 DOI: 10.1097/rli.0000000000000532] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to quantitatively assess changes in collagen structure using MR T1- and T2*-mapping in a novel controlled ex vivo tendon model setup. MATERIALS AND METHODS Twenty-four cadaveric bovine flexor tendons underwent MRI at 3 T before and after chemical modifications, representing mechanical degeneration and augmentation. Collagen degradation (COL), augmenting collagen fiber cross-linking (CXL), and a control (phosphate-buffered saline [PBS]) were examined in experimental groups, using histopathology as standard of reference. Variable echo-time and variable-flip angle gradient-echo sequences were used for T2*- and T1-mapping, respectively. Standard T1- and T2-weighted spin-echo sequences were acquired for visual assessment of tendon texture. Tendons were assessed subsequently for their biomechanical properties and compared with quantitative MRI analysis. RESULTS T1- and T2*-mapping was feasible and repeatable for untreated (mean, 545 milliseconds, 2.0 milliseconds) and treated tendons. Mean T1 and T2* values of COL, CXL, and PBS tendons were 1459, 934, and 1017 milliseconds, and 5.5, 3.6, and 2.5 milliseconds, respectively. T2* values were significantly different between enzymatically degraded tendons, cross-linked tendons, and controls, and were significantly correlated with mechanical tendon properties (r = -0.74, P < 0.01). T1 values and visual assessment could not differentiate CXL from PBS tendons. Photo-spectroscopy showed increased autofluorescence of cross-linked tendons, whereas histopathology verified degenerative lesions of enzymatically degraded tendons. CONCLUSIONS T2*-mapping has the potential to detect and quantify subtle changes in tendon collagen structure not visible on conventional clinical MRI. Tendon T2* values might serve as a biomarker for biochemical alterations associated with tendon pathology.
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12
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Pang Y. An order parameter without magic angle effect (OPTIMA) derived from R 1 ρ dispersion in ordered tissue. Magn Reson Med 2019; 83:1783-1795. [PMID: 31691348 DOI: 10.1002/mrm.28045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/25/2022]
Abstract
PURPOSE MR R2 imaging of ordered tissue exhibits the magic angle effect, potentially masking subtle pathological changes in cartilage. This work aimed to develop an orientation-independent order parameter (S) exclusively sensitive to collagen degeneration. METHODS A theory was developed based on R 1 ρ dispersion coupled with a simplified molecular motion model in which anisotropic R 2 a ( θ ) became directly proportional to correlation time τ b θ and S could be derived. This new parameter was validated with ex vivo R 1 ρ dispersion reported on orientated (n = 4), enzymatically depleted bovine cartilage (n = 6), and osteoarthritic human knee specimens (n = 14) at 9.4 Tesla, which was further demonstrated on 1 healthy human knee in vivo at 3 Tesla. RESULTS τ b θ from orientation-dependent R 1 ρ dispersion revealed a significantly high average correlation (r = 0.89 ± 0.05, P < 0.05) with R 2 a (θ) on cartilage samples and a moderate correlation (r = 0.48, P < 0.001) for the human knee in vivo. The derived S (10-3 ) significantly decreased in advanced osteoarthritis (1.64 ± 0.03 vs. 2.30 ± 0.11, P < 0.001) and collagen-depleted samples (1.30 ± 0.11 vs. 2.12 ± 0.12, P < 0.001) when compared with early osteoarthritis and the control, respectively. CONCLUSION The proposed order parameter could be a potentially useful orientation-independent MR biomarker for collagen alterations in cartilage and other highly structured tissues.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
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13
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Madhavi WAM, Weerasinghe S, Fullerton GD, Momot KI. Structure and Dynamics of Collagen Hydration Water from Molecular Dynamics Simulations: Implications of Temperature and Pressure. J Phys Chem B 2019; 123:4901-4914. [PMID: 31117617 DOI: 10.1021/acs.jpcb.9b03078] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dynamics of water molecules in hydrated collagen plays an important role in determining the structural and functional properties of collagenous tissues. Experimental results suggest that collagen-bridging water molecules exhibit dynamic and thermodynamic properties of one-dimensional ice. However, molecular dynamics (MD) studies performed to date have failed to identify icelike water bridges. It has been hypothesized that this discrepancy is due to the experimental measurements and computational MD analysis having been performed on very different systems: complete tissues with large-scale collagen fiber assemblies and individual tropocollagen fragments, respectively. In this work, we explore ways of emulating a tissuelike macromolecular environment in MD simulations of hydrated collagen without increasing the size of the system to computationally prohibitive levels. We have investigated the effects of temperature and pressure on the dynamics of a small hydrated tropocollagen fragment. The occupancy and bond energies of interchain hydrogen bonds were relatively insensitive to temperature, suggesting that they play a key role in the stability of the collagen triple helix. The lifetimes of water bridges lengthened with decreasing temperature, but even at 280 K, no bridging water molecules exhibited icelike dynamics. We discuss the implications of these findings for the ability to emulate tissuelike conditions in hydrated collagen.
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Affiliation(s)
- W A Monika Madhavi
- School of Chemistry, Physics and Mechanical Engineering , Queensland University of Technology (QUT) , GPO Box 2434, Brisbane , QLD 4001 , Australia
| | | | - Gary D Fullerton
- Department of Radiology , University of Texas Health SA , San Antonio , Texas 78229-3900 , United States
| | - Konstantin I Momot
- School of Chemistry, Physics and Mechanical Engineering , Queensland University of Technology (QUT) , GPO Box 2434, Brisbane , QLD 4001 , Australia
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Pang Y, Palmieri-Smith RM, Malyarenko DI, Swanson SD, Chenevert TL. A unique anisotropic R 2 of collagen degeneration (ARCADE) mapping as an efficient alternative to composite relaxation metric (R 2 -R 1 ρ ) in human knee cartilage study. Magn Reson Med 2019; 81:3763-3774. [PMID: 30793790 DOI: 10.1002/mrm.27621] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/11/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE Anisotropic transverse R2 (1/T2 ) relaxation of water proton is sensitive to cartilage degenerative changes. The purpose is to develop an efficient method to extract this relaxation metric in clinical studies. METHODS Anisotropic R2 can be measured inefficiently by standard R2 mapping after removing an isotropic contribution obtained from R1 ρ mapping. In the proposed method, named as a unique anisotropic R2 of collagen degeneration (ARCADE) mapping, an assumed uniform isotropic R2 was estimated at magic angle locations in the deep cartilage, and an anisotropic R2 was thus isolated in a single T2W sagittal image. Five human knees from 4 volunteers were studied with standard R2 and R1 ρ mappings at 3T, and anisotropic R2 derived from ARCADE on the T2W (TE = 48.8 ms) image from R2 mapping was compared with the composite relaxation (R2 - R1 ρ ) using statistical analysis including Student's t-test and Pearson's correlation coefficient. RESULTS Anisotropic R2 (1/s) from ARCADE was highly positively correlated with but not significantly different from standard R2 - R1 ρ (1/s) in the segmented deep (r = 0.83 ± 0.06; 8.3 ± 2.9 vs. 7.3 ± 1.9, P = .50) and the superficial (r = 0.82 ± 0.05; 3.5 ± 2.4 vs. 4.5 ± 1.6, P = .39) zones. However, after eliminating systematic errors by the normalization in terms of zonal contrast, anisotropic R2 was significantly higher (60.2 ± 18.5% vs. 38.4 ± 16.6%, P < .01) than R2 - R1 ρ as predicted. CONCLUSION The proposed anisotropic R2 mapping could be an efficient alternative to the conventional approach, holding great promise in providing both high-resolution morphological and more sensitive transverse relaxation imaging from a single T2W scan in a clinical setting.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Riann M Palmieri-Smith
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan.,Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan
| | | | - Scott D Swanson
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
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Abstract
Fascia is a cacophony of functions and information, a completely adaptable entropy complex. The fascial system has a solid and a liquid component, acting in a perfect symbiotic synchrony. Each cell communicates with the other cells by sending and receiving signals; this concept is a part of quantum physics and it is known as quantum entanglement: a physical system cannot be described individually, but only as a juxtaposition of multiple systems, where the measurement of a quantity determines the value for other systems. Fascial continuum serves as a target for different manual approaches, such as physiotherapy, osteopathy and chiropractic. Cellular behaviour and the inclusion of quantum physics background are hardly being considered to find out what happens between the operator and the patient during a manual physical contact. The article examines these topics. According to the authors' knowledge, this is the first scientific text to offer manual operators’ new perspectives to understand what happens during palpatory contact. A fascial cell has not only memory but also the awareness of the mechanometabolic information it feels, and it has the anticipatory predisposition in preparing itself for alteration of its natural environment.
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Affiliation(s)
- Bruno Bordoni
- Cardiology, Foundation Don Carlo Gnocchi / (IRCCS) Institute of Hospitalization and Care, Milano, ITA
| | - Marta Simonelli
- Osteopathy, (SOFI) School of French-Italian Osteopathy, Pisa, ITA
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Fielder M, Nair AK. Effects of hydration and mineralization on the deformation mechanisms of collagen fibrils in bone at the nanoscale. Biomech Model Mechanobiol 2018; 18:57-68. [PMID: 30088113 DOI: 10.1007/s10237-018-1067-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/30/2018] [Indexed: 12/25/2022]
Abstract
Bone is a biomaterial with a structural load-bearing function. Investigating the biomechanics of bone at the nanoscale is important in application to tissue engineering, the development of bioinspired materials, and for characterizing factors such as age, trauma, or disease. At the nanoscale, bone is composed of fibrils that are primarily a composite of collagen, apatite crystals (mineral), and water. Though several studies have been done characterizing the mechanics of fibrils, the effects of variation and distribution of water and mineral content in fibril gap and overlap regions are unexplored. We investigate how the deformation mechanisms of collagen fibrils change as a function of mineral and water content. We use molecular dynamics to study the mechanics of collagen fibrils of 0 wt%, 20 wt%, and 40 wt% mineralization and 0 wt%, 2 wt%, and 4 wt% hydration under applied tensile stresses. We observe that the stress-strain behavior becomes more nonlinear with an increase in hydration, and an increase in mineral content for hydrated fibrils under tensile stress reduces the nonlinear stress versus strain behavior caused by hydration. The Young's modulus of both non-mineralized and mineralized fibrils decreases as the water content increases. As the water content increases, the gap/overlap ratio increases by approximately 40% for the non-mineralized cases and 16% for the highly mineralized cases. Our results indicate that variations in mineral and water content change the distribution of water in collagen fibrils and that the water distribution changes the deformation of gap and overlap regions under tensile loading.
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Affiliation(s)
- Marco Fielder
- Multiscale Materials Modeling Lab, Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Arun K Nair
- Multiscale Materials Modeling Lab, Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR, USA. .,Institute for Nanoscience and Engineering, University of Arkansas, 731 W. Dickson Street, Fayetteville, AR, USA.
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Madhavi WAM, Weerasinghe S, Momot KI. Rotational-Diffusion Propagator of the Intramolecular Proton–Proton Vector in Liquid Water: A Molecular Dynamics Study. J Phys Chem B 2017; 121:10893-10905. [DOI: 10.1021/acs.jpcb.7b07551] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- W. A. Monika Madhavi
- School
of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Qld 4001, Australia
| | | | - Konstantin I. Momot
- School
of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Qld 4001, Australia
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Ali TS, Thibbotuwawa N, Gu Y, Momot KI. MRI magic-angle effect in femorotibial cartilages of the red kangaroo. Magn Reson Imaging 2017; 43:66-73. [PMID: 28716681 DOI: 10.1016/j.mri.2017.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/13/2017] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Kangaroo knee cartilages are robust tissues that can support knee flexion and endure high levels of compressive stress. This study aimed to develop a detailed understanding of the collagen architecture in kangaroo knee cartilages and thus obtain insights into the biophysical basis of their function. DESIGN Cylindrical/square plugs from femoral and tibial hyaline cartilage and tibial fibrocartilage were excised from the knees of three adult red kangaroos. Multi-slice, multi-echo MR images were acquired at the sample orientations 0° and 55° ("magic angle") with respect to the static magnetic field. Maps of the transverse relaxation rate constant (R2) and depth profiles of R2 and its anisotropic component (R2A) were constructed from the data. RESULTS The R2A profiles confirmed the classic three-zone organisation of all cartilage samples. Femoral hyaline cartilage possessed a well-developed, thick superficial zone. Tibial hyaline cartilage possessed a very thick radial zone (80% relative thickness) that exhibited large R2A values consistent with highly ordered collagen. The R2A profile of tibial fibrocartilage exhibited a unique region near the bone (bottom 5-10%) consistent with elevated proteoglycan content ("attachment sub-zone"). CONCLUSIONS Our observations suggest that the well-developed superficial zone of femoral hyaline cartilage is suitable for supporting knee flexion; the thick and well-aligned radial zone of tibial hyaline cartilage is adapted to endure high compressive stress; while the innermost part of the radial zone of tibial fibrocartilage may facilitate anchoring of the collagen fibres to withstand high shear deformation. These findings may inspire new designs for cartilage tissue engineering.
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Affiliation(s)
- Tonima S Ali
- Queensland University of Technology (QUT), Brisbane, Queensland, Australia; Institute of Health and Biomedical Innovation, Kelvin Grove, QLD 4059, Australia
| | - Namal Thibbotuwawa
- Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - YuanTong Gu
- Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Konstantin I Momot
- Queensland University of Technology (QUT), Brisbane, Queensland, Australia; Institute of Health and Biomedical Innovation, Kelvin Grove, QLD 4059, Australia.
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Karabencheva-Christova TG, Christov CZ, Fields GB. Collagenolytic Matrix Metalloproteinase Structure–Function Relationships: Insights From Molecular Dynamics Studies. STRUCTURAL AND MECHANISTIC ENZYMOLOGY 2017; 109:1-24. [DOI: 10.1016/bs.apcsb.2017.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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