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Abstract
Mechanical properties have been extensively studied in pure elastic or viscous materials; however, most biomaterials possess both physical properties in a viscoelastic component. How the biomechanics of a fibrin clot is related to its composition and the microenvironment where it is formed is not yet fully understood. This review gives an outline of the building mechanisms for blood clot mechanical properties and how they relate to clot function. The formation of a blood clot in health conditions or the formation of a dangerous thrombus go beyond the mere polymerization of fibrinogen into a fibrin network. The complex composition and localization of in vivo fibrin clots demonstrate the interplay between fibrin and/or fibrinogen and blood cells. Studying these protein–cell interactions and clot mechanical properties may represent new methods for the evaluation of cardiovascular diseases (the leading cause of death worldwide), creating new possibilities for clinical diagnosis, prognosis, and therapy. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Marco M. Domingues
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Filomena A. Carvalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Nuno C. Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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2
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Abstract
Fibrin is the main component of blood clots. The mechanical properties of fibrin are therefore of critical importance in successful hemostasis. One of the divalent cations released by platelets during hemostasis is Zn2+; however, its effect on the network structure of fibrin gels and on the resultant mechanical properties remains poorly understood. Here, by combining mechanical measurements with three-dimensional confocal microscopy imaging, we show that Zn2+ can tune the fibrin network structure and alter its mechanical properties. In the presence of Zn2+, fibrin protofibrils form large bundles that cause a coarsening of the fibrin network due to an increase in fiber diameter and reduction of the total fiber length. We further show that the protofibrils in these bundles are loosely coupled to one another, which results in a decrease of the elastic modulus with increasing Zn2+ concentrations. We explore the elastic properties of these networks at both low and high stress: At low stress, the elasticity originates from pulling the thermal slack out of the network, and this is consistent with the thermal bending of the fibers. By contrast, at high stress, the elasticity exhibits a common master curve consistent with the stretching of individual protofibrils. These results show that the mechanics of a fibrin network are closely correlated with its microscopic structure and inform our understanding of the structure and physical mechanisms leading to defective or excessive clot stiffness.
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Affiliation(s)
- Jing Xia
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Li-Heng Cai
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904
| | - Huayin Wu
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Frederick C MacKintosh
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77030
- Department of Chemistry and Physics, Rice University, Houston, TX 77005
- Department of Astronomy, Rice University, Houston, TX 77005
| | - David A Weitz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
- Department of Physics, Harvard University, Cambridge, MA 02138
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3
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Coyac BR, Leahy B, Li Z, Salvi G, Yin X, Brunski JB, Helms JA. Bone formation around unstable implants is enhanced by a WNT protein therapeutic in a preclinical in vivo model. Clin Oral Implants Res 2020; 31:1125-1137. [PMID: 32881143 DOI: 10.1111/clr.13659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/10/2020] [Accepted: 08/08/2020] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Our objective was to test the hypothesis that local delivery of a WNT protein therapeutic would support osseointegration of an unstable implant placed into an oversized osteotomy and subjected to functional loading. MATERIALS AND METHODS Using a split-mouth design in an ovariectomized (OVX) rat model, 50 titanium implants were placed in oversized osteotomies. Implants were subjected to functional loading. One-half of the implants were treated with a liposomal formulation of WNT3A protein (L-WNT3A); the other half received an identical liposomal formulation containing phosphate-buffered saline (PBS). Finite element modeling estimated peri-implant strains caused by functional loading. Histological, molecular, cellular, and quantitative micro-computed tomographic (µCT) imaging analyses were performed on samples from post-implant days (PID) 3, 7, and 14. Lateral implant stability was quantified at PID 7 and 14. RESULTS Finite element analyses predicted levels of peri-implant strains incompatible with new bone formation. Micro-CT imaging, histological, and quantitative immunohistochemical (IHC) analyses confirmed that PBS-treated implants underwent fibrous encapsulation. In those cases where the peri-implant environment was treated with L-WNT3A, µCT imaging, histological, and quantitative IHC analyses demonstrated a significant increase in expression of proliferative (PCNA) and osteogenic (Runx2, Osterix) markers. One week after L-WNT3A treatment, new bone formation was evident, and two weeks later, L-WNT3A-treated gaps had a stiffer interface compared to PBS-treated gaps. CONCLUSION In a rat model, unstable implants undergo fibrous encapsulation. If the same unstable implants are treated with L-WNT3A at the time of placement, then it results in significantly more peri-implant bone and greater interfacial stiffness.
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Affiliation(s)
- Benjamin R Coyac
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Brian Leahy
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Zhijun Li
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Giuseppe Salvi
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Xing Yin
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - John B Brunski
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Jill A Helms
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
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4
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Yesudasan S, Averett RD. Multiscale Network Modeling of Fibrin Fibers and Fibrin Clots with Protofibril Binding Mechanics. Polymers (Basel) 2020; 12:E1223. [PMID: 32471225 DOI: 10.3390/polym12061223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/22/2020] [Accepted: 05/19/2020] [Indexed: 11/17/2022] Open
Abstract
The multiscale mechanical behavior of individual fibrin fibers and fibrin clots was modeled by coupling atomistic simulation data and microscopic experimental data. We propose a new protofibril element composed of a nonlinear spring network, and constructed this based on molecular simulations and atomic force microscopy results to simulate the force extension behavior of fibrin fibers. This new network model also accounts for the complex interaction of protofibrils with one another, the effects of the presence of a solvent, Coulombic attraction, and other binding forces. The network model was formulated to simulate the force–extension mechanical behavior of single fibrin fibers from atomic force microscopy experiments, and shows good agreement. The validated fibrin fiber network model was then combined with a modified version of the Arruda–Boyce eight-chain model to estimate the force extension behavior of the fibrin clot at the continuum level, which shows very good correlation. The results show that our network model is able to predict the behavior of fibrin fibers as well as fibrin clots at small strains, large strains, and close to the break strain. We used the network model to explain why the mechanical response of fibrin clots and fibrin fibers deviates from worm-like chain behavior, and instead behaves like a nonlinear spring.
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5
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Abstract
The formation of a fibrin clot matrix plays a critical role in promoting hemostasis and wound healing. Fibrin dynamics can become disadvantageous in the formation of aberrant thrombus development. Structural characteristics of clots, such as fiber diameter, clot density, stiffness, or permeability, can determine overall clot integrity and functional characteristics that have implications on coagulation and fibrinolysis. This review examines known factors that contribute to changes in clot structure and the presence of structural clot changes in various disease states. These insights provide valuable information in forming therapeutic strategies for disease states where alterations in clot structure are observed. Additionally, the implications of structural changes in clot networks on bleeding and thrombus development in terms of disease states and clinical outcomes are also examined in this review.
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Affiliation(s)
- Emily Mihalko
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina
| | - Ashley C Brown
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina
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6
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de Barros E Lima Bueno R, Dias AP, Ponce KJ, Brunski JB, Nanci A. System for application of controlled forces on dental implants in rat maxillae: Influence of the number of load cycles on bone healing. J Biomed Mater Res B Appl Biomater 2019; 108:965-975. [PMID: 31368244 PMCID: PMC7078813 DOI: 10.1002/jbm.b.34449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 07/03/2019] [Accepted: 07/13/2019] [Indexed: 12/26/2022]
Abstract
Experimental studies on the effect of micromotion on bone healing around implants are frequently conducted in long bones. In order to more closely reflect the anatomical and clinical environments around dental implants, and eventually be able to experimentally address load‐management issues, we have developed a system that allows initial stabilization, protection from external forces, and controlled axial loading of implants. Screw‐shaped implants were placed on the edentulous ridge in rat maxillae. Three loading regimens were applied to validate the system; case A no loading (unloaded implant) for 14 days, case B no loading in the first 7 days followed by 7 days of a single, daily loading session (60 cycles of an axial force of 1.5 N/cycle), and case C no loading in the first 7 days followed by 7 days of two such daily loading sessions. Finite element modeling of the peri‐implant compressive and tensile strains plus histological and immunohistochemical analyses revealed that in case B any tissue damage resulting from the applied force (and related interfacial strains) did not per se disturb bone healing, however, in case C, the accumulation of damage resulting from the doubling of loading sessions severely disrupted the process. These proof‐of‐principle results validate the applicability of our system for controlled loading, and provide new evidence on the importance of the number of load cycles applied on healing of maxillary bone.
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Affiliation(s)
- Renan de Barros E Lima Bueno
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
| | - Ana P Dias
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
| | - Katia J Ponce
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
| | - John B Brunski
- Department of Surgery, School of Medicine, Stanford University, Stanford, California
| | - Antonio Nanci
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
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7
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Affiliation(s)
- Bo Gong
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Xi Wei
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Jin Qian
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
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8
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de Barros E Lima Bueno R, Dias AP, Ponce KJ, Wazen R, Brunski JB, Nanci A. Bone healing response in cyclically loaded implants: Comparing zero, one, and two loading sessions per day. J Mech Behav Biomed Mater 2018; 85:152-161. [PMID: 29894930 PMCID: PMC6035061 DOI: 10.1016/j.jmbbm.2018.05.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/16/2018] [Accepted: 05/30/2018] [Indexed: 01/15/2023]
Abstract
When bone implants are loaded, they are inevitably subjected to displacement relative to bone. Such micro-motion generates stress/strain states at the interface that can cause beneficial or detrimental sequels. The objective of this study is to better understand the mechanobiology of bone healing at the tissue-implant interface during repeated loading. Machined screw shaped Ti implants were placed in rat tibiae in a hole slightly bigger than the implant diameter. Implants were held stable by a specially-designed bone plate that permits controlled loading. Three loading regimens were applied, (a) zero loading, (b) one daily loading session of 60 cycles with an axial force of 1.5 N/cycle for 7 days, and (c) two such daily sessions with the same axial force also for 7 days. Finite element analysis was used to characterize the mechanobiological conditions produced by the loading sessions. After 7 days, the implants with surrounding interfacial tissue were harvested and processed for histological, histomorphometric and DNA microarray analyses. Histomorphometric analyses revealed that the group subjected to repeated loading sessions exhibited a significant decrease in bone-implant contact and increase in bone-implant distance, as compared to unloaded implants and those subjected to only one loading session. Gene expression profiles differed during osseointegration between all groups mainly with respect to inflammatory and unidentified gene categories. The results indicate that increasing the daily cyclic loading of implants induces deleterious changes in the bone healing response, most likely due to the accumulation of tissue damage and associated inflammatory reaction at the bone-implant interface.
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Affiliation(s)
- Renan de Barros E Lima Bueno
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - Ana Paula Dias
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - Katia J Ponce
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - Rima Wazen
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - John B Brunski
- Department of Surgery, School of Medicine, Stanford University, Stanford, CA, United States
| | - Antonio Nanci
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada.
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9
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Abstract
Fibrinogen and fibrin are essential for hemostasis and are major factors in thrombosis, wound healing, and several other biological functions and pathological conditions. The X-ray crystallographic structure of major parts of fibrin(ogen), together with computational reconstructions of missing portions and numerous biochemical and biophysical studies, have provided a wealth of data to interpret molecular mechanisms of fibrin formation, its organization, and properties. On cleavage of fibrinopeptides by thrombin, fibrinogen is converted to fibrin monomers, which interact via knobs exposed by fibrinopeptide removal in the central region, with holes always exposed at the ends of the molecules. The resulting half-staggered, double-stranded oligomers lengthen into protofibrils, which aggregate laterally to make fibers, which then branch to yield a three-dimensional network. Much is now known about the structural origins of clot mechanical properties, including changes in fiber orientation, stretching and buckling, and forced unfolding of molecular domains. Studies of congenital fibrinogen variants and post-translational modifications have increased our understanding of the structure and functions of fibrin(ogen). The fibrinolytic system, with the zymogen plasminogen binding to fibrin together with tissue-type plasminogen activator to promote activation to the active proteolytic enzyme, plasmin, results in digestion of fibrin at specific lysine residues. In spite of a great increase in our knowledge of all these interconnected processes, much about the molecular mechanisms of the biological functions of fibrin(ogen) remains unknown, including some basic aspects of clotting, fibrinolysis, and molecular origins of fibrin mechanical properties. Even less is known concerning more complex (patho)physiological implications of fibrinogen and fibrin.
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Affiliation(s)
- John W Weisel
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
| | - Rustem I Litvinov
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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10
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Kell DB, Pretorius E. Proteins behaving badly. Substoichiometric molecular control and amplification of the initiation and nature of amyloid fibril formation: lessons from and for blood clotting. Progress in Biophysics and Molecular Biology 2017; 123:16-41. [DOI: 10.1016/j.pbiomolbio.2016.08.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/14/2016] [Accepted: 08/19/2016] [Indexed: 02/08/2023]
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11
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Badiei N, Sowedan AM, Curtis DJ, Brown MR, Lawrence MJ, Campbell AI, Sabra A, Evans PA, Weisel JW, Chernysh IN, Nagaswami C, Williams PR, Hawkins K. Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels. Clin Hemorheol Microcirc 2016; 60:451-64. [PMID: 25624413 PMCID: PMC4923731 DOI: 10.3233/ch-151924] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (df) of the fibrin network, the gel network formation time (TGP) and the shear elastic modulus, respectively. The results of this first haemorheological application of CSPS reveal the marked sensitivity of incipient clot microstructure to physiologically relevant levels of shear stress, these being an order of magnitude lower than have previously been studied by SAOS. CSPS tests revealed that exposure of forming clots to increasing levels of shear stress produces a corresponding elevation in df, consistent with the formation of tighter, more compact clot microstructures under unidirectional flow. A corresponding increase in shear elasticity was recorded. The scaling relationship established between shear elasticity and df for fibrin clots and whole blood confirms the fibrin network as the dominant microstructural component of the incipient clot in terms of its response to imposed stress. Supplementary studies of fibrin clot formation by rheometry and microscopy revealed the substantial additional network mass required to increase df and provide evidence to support the hypothesis that microstructural changes in blood clotted under unidirectional shear may be attributed to flow enhanced thrombin generation and activation. CSPS also identified a threshold value of unidirectional shear stress above which no incipient clot formation could be detected. CSPS was shown to be a valuable haemorheological tool for the study of the effects of physiological and pathological levels of shear on clot properties.
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Affiliation(s)
- N Badiei
- College of Engineering, Swansea University, Swansea, UK
| | - A M Sowedan
- College of Engineering, Swansea University, Swansea, UK.,College of Medicine, Swansea University, Swansea, UK
| | - D J Curtis
- College of Engineering, Swansea University, Swansea, UK
| | - M R Brown
- College of Engineering, Swansea University, Swansea, UK
| | - M J Lawrence
- College of Medicine, Swansea University, Swansea, UK.,NISCHR Clinical Haemostasis and Biomarker Research Unit, ABMU NHS Trust Hospital, Morriston, Swansea, UK
| | - A I Campbell
- College of Engineering, Swansea University, Swansea, UK
| | - A Sabra
- College of Medicine, Swansea University, Swansea, UK.,NISCHR Clinical Haemostasis and Biomarker Research Unit, ABMU NHS Trust Hospital, Morriston, Swansea, UK
| | - P A Evans
- College of Medicine, Swansea University, Swansea, UK.,NISCHR Clinical Haemostasis and Biomarker Research Unit, ABMU NHS Trust Hospital, Morriston, Swansea, UK
| | - J W Weisel
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - I N Chernysh
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - C Nagaswami
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - P R Williams
- College of Engineering, Swansea University, Swansea, UK
| | - K Hawkins
- College of Medicine, Swansea University, Swansea, UK.,NISCHR Clinical Haemostasis and Biomarker Research Unit, ABMU NHS Trust Hospital, Morriston, Swansea, UK
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12
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Abstract
Fibrin is a protein polymer that is essential for hemostasis and thrombosis, wound healing, and several other biological functions and pathological conditions that involve extracellular matrix. In addition to molecular and cellular interactions, fibrin mechanics has been recently shown to underlie clot behavior in the highly dynamic intra- and extravascular environments. Fibrin has both elastic and viscous properties. Perhaps the most remarkable rheological feature of the fibrin network is an extremely high elasticity and stability despite very low protein content. Another important mechanical property that is common to many filamentous protein polymers but not other polymers is stiffening occurring in response to shear, tension, or compression. New data has begun to provide a structural basis for the unique mechanical behavior of fibrin that originates from its complex multi-scale hierarchical structure. The mechanical behavior of the whole fibrin gel is governed largely by the properties of single fibers and their ensembles, including changes in fiber orientation, stretching, bending, and buckling. The properties of individual fibrin fibers are determined by the number and packing arrangements of double-stranded half-staggered protofibrils, which still remain poorly understood. It has also been proposed that forced unfolding of sub-molecular structures, including elongation of flexible and relatively unstructured portions of fibrin molecules, can contribute to fibrin deformations. In spite of a great increase in our knowledge of the structural mechanics of fibrin, much about the mechanisms of fibrin's biological functions remains unknown. Fibrin deformability is not only an essential part of the biomechanics of hemostasis and thrombosis, but also a rapidly developing field of bioengineering that uses fibrin as a versatile biomaterial with exceptional and tunable biochemical and mechanical properties.
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Affiliation(s)
- Rustem I Litvinov
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - John W Weisel
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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13
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Wang X, Friis T, Glatt V, Crawford R, Xiao Y. Structural properties of fracture haematoma: current status and future clinical implications. J Tissue Eng Regen Med 2016; 11:2864-2875. [PMID: 27401283 DOI: 10.1002/term.2190] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/12/2016] [Accepted: 03/14/2016] [Indexed: 12/24/2022]
Abstract
Blood clots (haematomas) that form immediately following a bone fracture have been shown to be vital for the subsequent healing process. During the clotting process, a number of factors can influence the fibrin clot structure, such as fibrin polymerization, growth factor binding, cellular infiltration (including platelet retraction), protein concentrations and cytokines. The modulation of the fibrin clot structure within the fracture site has important clinical implications and could result in the development of multifunctional scaffolds that mimic the natural structure of a haematoma. Artificial haematoma structures such as these can be created from the patient's own blood and can therefore act as an ideal bone defect filling material for potential clinical application to accelerate bone regeneration. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Xin Wang
- Department of Spine, Affiliated Hospital of Zunyi Medical College, Zunyi, People's Republic of China.,Science and Engineering Faculty, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Queensland University of Technology, Brisbane, Australia
| | - Thor Friis
- Science and Engineering Faculty, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Queensland University of Technology, Brisbane, Australia
| | - Vaida Glatt
- Science and Engineering Faculty, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Ross Crawford
- Science and Engineering Faculty, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Queensland University of Technology, Brisbane, Australia
| | - Yin Xiao
- Science and Engineering Faculty, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Queensland University of Technology, Brisbane, Australia
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14
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Fleissner F, Bonn M, Parekh SH. Microscale spatial heterogeneity of protein structural transitions in fibrin matrices. Sci Adv 2016; 2:e1501778. [PMID: 28861472 PMCID: PMC5566164 DOI: 10.1126/sciadv.1501778] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/13/2016] [Indexed: 05/23/2023]
Abstract
Following an injury, a blood clot must form at the wound site to stop bleeding before skin repair can occur. Blood clots must satisfy a unique set of material requirements; they need to be sufficiently strong to resist pressure from the arterial blood flow but must be highly flexible to support large strains associated with tissue movement around the wound. These combined properties are enabled by a fibrous matrix consisting of the protein fibrin. Fibrin hydrogels can support large macroscopic strains owing to the unfolding transition of α-helical fibril structures to β sheets at the molecular level, among other reasons. Imaging protein secondary structure on the submicrometer length scale, we reveal that another length scale is relevant for fibrin function. We observe that the protein polymorphism in the gel becomes spatially heterogeneous on a micrometer length scale with increasing tensile strain, directly showing load-bearing inhomogeneity and nonaffinity. Supramolecular structural features in the hydrogel observed under strain indicate that a uniform fibrin hydrogel develops a composite-like microstructure in tension, even in the absence of cellular inclusions.
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15
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Kim OV, Litvinov RI, Weisel JW, Alber MS. Structural basis for the nonlinear mechanics of fibrin networks under compression. Biomaterials 2014; 35:6739-49. [PMID: 24840618 DOI: 10.1016/j.biomaterials.2014.04.056] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 04/12/2014] [Indexed: 12/14/2022]
Abstract
Fibrin is a protein polymer that forms a 3D filamentous network, a major structural component of protective physiological blood clots as well as life threatening pathological thrombi. It plays an important role in wound healing, tissue regeneration and is widely employed in surgery as a sealant and in tissue engineering as a scaffold. The goal of this study was to establish correlations between structural changes and mechanical responses of fibrin networks exposed to compressive loads. Rheological measurements revealed nonlinear changes of fibrin network viscoelastic properties under dynamic compression, resulting in network softening followed by its dramatic hardening. Repeated compression/decompression enhanced fibrin clot stiffening. Combining fibrin network rheology with simultaneous confocal microscopy provided direct evidence of structural modulations underlying nonlinear viscoelasticity of compressed fibrin networks. Fibrin clot softening in response to compression strongly correlated with fiber buckling and bending, while hardening was associated with fibrin network densification. Our results suggest a complex interplay of entropic and enthalpic mechanisms accompanying structural changes and accounting for the nonlinear mechanical response in fibrin networks undergoing compressive deformations. These findings provide new insight into the fibrin clot structural mechanics and can be useful for designing fibrin-based biomaterials with modulated viscoelastic properties.
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Affiliation(s)
- Oleg V Kim
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Rustem I Litvinov
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, 1154 BRB II/III, 421 Curie Boulevard, Philadelphia, PA 19104-6058, USA
| | - John W Weisel
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, 1154 BRB II/III, 421 Curie Boulevard, Philadelphia, PA 19104-6058, USA.
| | - Mark S Alber
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46556, USA.
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