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Sugerman GP, Bechtel GN, Malinowska Z, Parekh SH, Rausch MK. Mechanical properties of clot made from human and bovine whole blood differ significantly. J Mech Behav Biomed Mater 2024; 154:106508. [PMID: 38513312 DOI: 10.1016/j.jmbbm.2024.106508] [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: 08/18/2023] [Revised: 02/24/2024] [Accepted: 03/13/2024] [Indexed: 03/23/2024]
Abstract
Thromboembolism - that is, clot formation and the subsequent fragmentation of clot - is a leading cause of death worldwide. Clots' mechanical properties are critical determinants of both the embolization process and the pathophysiological consequences thereof. Thus, understanding and quantifying the mechanical properties of clots is important to our ability to treat and prevent thromboembolic disease. However, assessing these properties from in vivo clots is experimentally challenging. Therefore, we and others have turned to studying in vitro clot mimics instead. Unfortunately, there are significant discrepancies in the reported properties of these clot mimics, which have been hypothesized to arise from differences in experimental techniques and blood sources. The goal of our current work is therefore to compare the mechanical behavior of clots made from the two most common sources, human and bovine blood, using the same experimental techniques. To this end, we tested clots under pure shear with and without initial cracks, under cyclic loading, and under stress relaxation. Based on these data, we computed and compared stiffness, strength, work-to-rupture, fracture toughness, relaxation time constants, and prestrain. While clots from both sources behaved qualitatively similarly, they differed quantitatively in almost every metric. We also correlated each mechanical metric to measures of blood composition. Thereby, we traced this inter-species variability in clot mechanics back to significant differences in hematocrit, but not platelet count. Thus, our work suggests that the results of past studies that have used bovine blood to make in vitro mimics - without adjusting blood composition - should be interpreted carefully. Future studies about the mechanical properties of blood clots should focus on human blood alone.
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Affiliation(s)
- Gabriella P Sugerman
- University of Texas at Austin, Department of Biomedical Engineering, 107 W Dean Keeton St, Austin, TX 78712, United States of America
| | - Grace N Bechtel
- University of Texas at Austin, Department of Biomedical Engineering, 107 W Dean Keeton St, Austin, TX 78712, United States of America
| | - Zuzanna Malinowska
- University of Texas at Austin, Department of Aerospace Engineering & Engineering Mechanics, 2617 Wichita St, Austin, TX 78712, United States of America
| | - Sapun H Parekh
- University of Texas at Austin, Department of Biomedical Engineering, 107 W Dean Keeton St, Austin, TX 78712, United States of America
| | - Manuel K Rausch
- University of Texas at Austin, Department of Biomedical Engineering, 107 W Dean Keeton St, Austin, TX 78712, United States of America; University of Texas at Austin, Department of Aerospace Engineering & Engineering Mechanics, 2617 Wichita St, Austin, TX 78712, United States of America; University of Texas at Austin, Department of Mechanical Engineering, 204 E Dean Keeton St, Austin, TX 78712, United States of America; University of Texas at Austin, Oden Institute for Computational Engineering and Sciences, 201 E 24th St, Austin, TX 78712, United States of America.
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2
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Ramanujam RK, Garyfallogiannis K, Litvinov RI, Bassani JL, Weisel JW, Purohit PK, Tutwiler V. Mechanics and microstructure of blood plasma clots in shear driven rupture. SOFT MATTER 2024; 20:4184-4196. [PMID: 38686609 PMCID: PMC11135145 DOI: 10.1039/d4sm00042k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/18/2024] [Indexed: 05/02/2024]
Abstract
Intravascular blood clots are subject to hydrodynamic shear and other forces that cause clot deformation and rupture (embolization). A portion of the ruptured clot can block blood flow in downstream vessels. The mechanical stability of blood clots is determined primarily by the 3D polymeric fibrin network that forms a gel. Previous studies have primarily focused on the rupture of blood plasma clots under tensile loading (Mode I), our current study investigates the rupture of fibrin induced by shear loading (Mode II), dominating under physiological conditions induced by blood flow. Using experimental and theoretical approaches, we show that fracture toughness, i.e. the critical energy release rate, is relatively independent of the type of loading and is therefore a fundamental property of the gel. Ultrastructural studies and finite element simulations demonstrate that cracks propagate perpendicular to the direction of maximum stretch at the crack tip. These observations indicate that locally, the mechanism of rupture is predominantly tensile. Knowledge gained from this study will aid in the development of methods for prediction/prevention of thrombotic embolization.
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Affiliation(s)
- Ranjini K Ramanujam
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, USA.
| | | | - Rustem I Litvinov
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - John L Bassani
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA
| | - John W Weisel
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Prashant K Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA
| | - Valerie Tutwiler
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, USA.
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3
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Poulos DA, Keith JS, Froehler MT, Good BC. Experimental evaluation of the plunger technique: A method of cyclic manual aspiration thrombectomy for treatment of acute ischemic stroke. Interv Neuroradiol 2024:15910199241230364. [PMID: 38321875 DOI: 10.1177/15910199241230364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Mechanical thrombectomy via direct aspiration is a rapid treatment for acute ischemic stroke. This method often results in the partial ingestion of the clot or "corking" of the catheter tip. Cyclic aspiration may take advantage of the mechanical properties of the clot, resulting in greater clot ingestion and overall procedure success. METHODS An in vitro analysis was performed comparing static and cyclic (plunger technique) aspiration. Embolus analogs were used to create occlusions in a mock circulatory flow loop, and one aspiration attempt (first pass effect) using either a static or plunger technique was performed. The percent ingestion of each embolus analog was recorded for each trial. RESULTS Static aspiration for 0% and 50% hematocrit embolus analogs resulted in ingestions of 12.8 ± 4.6% and 15.1 ± 10.0%, respectively, while plunger technique (cyclic) aspiration resulted in 15.8 ± 7.3% and 34.4 ± 19.5% ingestion. Complete ingestion was observed only with 50% hematocrit analogs, occurring in 30% of plunger and 10% of static cases. Statistical differences were determined between the two aspiration techniques for the 50% hematocrit samples, with the plunger technique yielding significantly more ingestion. In addition, the plunger technique was shown to maintain a negative vacuum pressure throughout the duration of cyclic plunging. CONCLUSIONS The plunger technique for manual cyclic aspiration resulted in higher rates of complete ingestion and greater average % ingestions when compared to static aspiration. Increased clot ingestion can result in a higher rate of complete reperfusion during the first aspiration attempt, maximizing the number of patients with good clinical outcomes.
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Affiliation(s)
- Demitria A Poulos
- Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Knoxville, TN, USA
| | - James S Keith
- Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Knoxville, TN, USA
| | - Michael T Froehler
- Cerebrovascular Program, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bryan C Good
- Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Knoxville, TN, USA
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4
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Eyisoylu H, Hazekamp ED, Cruts J, Koenderink GH, de Maat MPM. Flow affects the structural and mechanical properties of the fibrin network in plasma clots. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2024; 35:8. [PMID: 38285167 PMCID: PMC10824866 DOI: 10.1007/s10856-024-06775-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 01/02/2024] [Indexed: 01/30/2024]
Abstract
The fibrin network is one of the main components of thrombi. Altered fibrin network properties are known to influence the development and progression of thrombotic disorders, at least partly through effects on the mechanical stability of fibrin. Most studies investigating the role of fibrin in thrombus properties prepare clots under static conditions, missing the influence of blood flow which is present in vivo. In this study, plasma clots in the presence and absence of flow were prepared inside a Chandler loop. Recitrated plasma from healthy donors were spun at 0 and 30 RPM. The clot structure was characterized using scanning electron microscopy and confocal microscopy and correlated with the stiffness measured by unconfined compression testing. We quantified fibrin fiber density, pore size, and fiber thickness and bulk stiffness at low and high strain values. Clots formed under flow had thinner fibrin fibers, smaller pores, and a denser fibrin network with higher stiffness values compared to clots formed in absence of flow. Our findings indicate that fluid flow is an essential factor to consider when developing physiologically relevant in vitro thrombus models used in researching thrombectomy outcomes or risk of embolization.
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Affiliation(s)
- Hande Eyisoylu
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Emma D Hazekamp
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Janneke Cruts
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands.
| | - Moniek P M de Maat
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
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5
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Zakharov A, Awan M, Cheng T, Gopinath A, Lee SJJ, Ramasubramanian AK, Dasbiswas K. Clots reveal anomalous elastic behavior of fiber networks. SCIENCE ADVANCES 2024; 10:eadh1265. [PMID: 38198546 PMCID: PMC10780871 DOI: 10.1126/sciadv.adh1265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 12/06/2023] [Indexed: 01/12/2024]
Abstract
The adaptive mechanical properties of soft and fibrous biological materials are relevant to their functionality. The emergence of the macroscopic response of these materials to external stress and intrinsic cell traction from local deformations of their structural components is not well understood. Here, we investigate the nonlinear elastic behavior of blood clots by combining microscopy, rheology, and an elastic network model that incorporates the stretching, bending, and buckling of constituent fibrin fibers. By inhibiting fibrin cross-linking in blood clots, we observe an anomalous softening regime in the macroscopic shear response as well as a reduction in platelet-induced clot contractility. Our model explains these observations from two independent macroscopic measurements in a unified manner, through a single mechanical parameter, the bending stiffness of individual fibers. Supported by experimental evidence, our mechanics-based model provides a framework for predicting and comprehending the nonlinear elastic behavior of blood clots and other active biopolymer networks in general.
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Affiliation(s)
- Andrei Zakharov
- Department of Physics, University of California, Merced, Merced, CA 95343, USA
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Myra Awan
- Department of Chemical and Materials Engineering, San José State University, San José, CA 95192, USA
| | - Terrence Cheng
- Department of Chemical and Materials Engineering, San José State University, San José, CA 95192, USA
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
| | - Sang-Joon John Lee
- Department of Mechanical Engineering, San José State University, San José, CA 95192, USA
| | - Anand K. Ramasubramanian
- Department of Chemical and Materials Engineering, San José State University, San José, CA 95192, USA
| | - Kinjal Dasbiswas
- Department of Physics, University of California, Merced, Merced, CA 95343, USA
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6
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Du F, A W, Liu F, Wu B, Liu Y, Zheng W, Feng W, Li G, Wang X. Hydrophilic chitosan/graphene oxide composite sponge for rapid hemostasis and non-rebleeding removal. Carbohydr Polym 2023; 316:121058. [PMID: 37321741 DOI: 10.1016/j.carbpol.2023.121058] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 05/18/2023] [Accepted: 05/23/2023] [Indexed: 06/17/2023]
Abstract
Hydrophilic hemostatic sponge plays an important role in trauma bleeding control because of its robust coagulant functions. However, its strong tissue adhesion can easily result in wound tear and rebleeding during removing the sponge. Herein, the design of a hydrophilic anti-adhesive chitosan/graphene oxide composite sponge (CSAG) that possesses stable mechanical strength, rapid liquid absorption and strong intrinsic/extrinsic coagulation stimulations, is reported. For one thing, CSAG exhibits outstanding hemostatic performance, which significantly outperforms two commercial hemostats in two in vivo serious bleeding models. For another, CSAG shows low tissue adhesion; its peeling force is approximately 79.3 % lower than the commercial gauze. Moreover, in the peeling process, CSAG triggers partial detachment of the blood scab, because of the exist of bubbles or cavities at the interface, allowing the CSAG to be easily and safely peeled off from the wound without rebleeding. This study opens new avenues in constructing anti-adhesive trauma hemostatic materials.
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Affiliation(s)
- Fanglin Du
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Wenjing A
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Fang Liu
- Department of Oncology of Integrative Chinese and Western Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Bingxin Wu
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Yichun Liu
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Weitao Zheng
- Hubei Provincial Key Laboratory of Industrial Microbiology, Sino-German Biomedical Center, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan 430068, Hubei Province, China
| | - Wenli Feng
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Guofeng Li
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Xing Wang
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
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7
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Varner H, Sugerman GP, Rausch MK, Cohen T. Elasticity of whole blood clots measured via Volume Controlled Cavity Expansion. J Mech Behav Biomed Mater 2023; 143:105901. [PMID: 37207527 DOI: 10.1016/j.jmbbm.2023.105901] [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: 01/27/2023] [Revised: 04/29/2023] [Accepted: 05/07/2023] [Indexed: 05/21/2023]
Abstract
Measuring and understanding the mechanical properties of blood clots can provide insights into disease progression and the effectiveness of potential treatments. However, several limitations hinder the use of standard mechanical testing methods to measure the response of soft biological tissues, like blood clots. These tissues can be difficult to mount, and are inhomogeneous, irregular in shape, scarce, and valuable. To remedy this, we employ in this work Volume Controlled Cavity Expansion (VCCE), a technique that was recently developed, to measure local mechanical properties of soft materials in their natural environment. Through highly controlled volume expansion of a water bubble at the tip of an injection needle, paired with simultaneous measurement of the resisting pressure, we obtain a local signature of whole blood clot mechanical response. Comparing this data with predictive theoretical models, we find that a 1-term Ogden model is sufficient to capture the nonlinear elastic response observed in our experiments and produces shear modulus values that are comparable to values reported in the literature. Moreover, we find that bovine whole blood stored at 4 °C for greater than 2 days exhibits a statistically significant shift in the shear modulus from 2.53 ± 0.44 kPa on day 2 (N = 13) to 1.23 ± 0.18 kPa on day 3 (N = 14). In contrast to previously reported results, our samples did not exhibit viscoelastic rate sensitivity within strain rates ranging from 0.22 - 21.1 s-1. By surveying existing data on whole blood clots for comparison, we show that this technique provides highly repeatable and reliable results, hence we propose the more widespread adoption of VCCE as a path forward to building a better understanding of the mechanics of soft biological materials.
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Affiliation(s)
- Hannah Varner
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Gabriella P Sugerman
- Department of Biomedical Engineering, University of Texas at Austin, Austin, 78712, TX, USA
| | - Manuel K Rausch
- Department of Biomedical Engineering, University of Texas at Austin, Austin, 78712, TX, USA; Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, Austin, 78712, TX, USA; Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, 78712, TX, USA
| | - Tal Cohen
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.
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8
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Cahalane RME, de Vries JJ, de Maat MPM, van Gaalen K, van Beusekom HM, van der Lugt A, Fereidoonnezhad B, Akyildiz AC, Gijsen FJH. Tensile and Compressive Mechanical Behaviour of Human Blood Clot Analogues. Ann Biomed Eng 2023:10.1007/s10439-023-03181-6. [PMID: 37071278 DOI: 10.1007/s10439-023-03181-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/27/2023] [Indexed: 04/19/2023]
Abstract
Endovascular thrombectomy procedures are significantly influenced by the mechanical response of thrombi to the multi-axial loading imposed during retrieval. Compression tests are commonly used to determine compressive ex vivo thrombus and clot analogue stiffness. However, there is a shortage of data in tension. This study compares the tensile and compressive response of clot analogues made from the blood of healthy human donors in a range of compositions. Citrated whole blood was collected from six healthy human donors. Contracted and non-contracted fibrin clots, whole blood clots and clots reconstructed with a range of red blood cell (RBC) volumetric concentrations (5-80%) were prepared under static conditions. Both uniaxial tension and unconfined compression tests were performed using custom-built setups. Approximately linear nominal stress-strain profiles were found under tension, while strong strain-stiffening profiles were observed under compression. Low- and high-strain stiffness values were acquired by applying a linear fit to the initial and final 10% of the nominal stress-strain curves. Tensile stiffness values were approximately 15 times higher than low-strain compressive stiffness and 40 times lower than high-strain compressive stiffness values. Tensile stiffness decreased with an increasing RBC volume in the blood mixture. In contrast, high-strain compressive stiffness values increased from 0 to 10%, followed by a decrease from 20 to 80% RBC volumes. Furthermore, inter-donor differences were observed with up to 50% variation in the stiffness of whole blood clot analogues prepared in the same manner between healthy human donors.
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Affiliation(s)
- Rachel M E Cahalane
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Judith J de Vries
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Moniek P M de Maat
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Kim van Gaalen
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Heleen M van Beusekom
- Experimental Cardiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Behrooz Fereidoonnezhad
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Ali C Akyildiz
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Frank J H Gijsen
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.
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9
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Proestaki M, Sarkar M, Burkel BM, Ponik SM, Notbohm J. Effect of hyaluronic acid on microscale deformations of collagen gels. J Mech Behav Biomed Mater 2022; 135:105465. [PMID: 36154991 PMCID: PMC9575965 DOI: 10.1016/j.jmbbm.2022.105465] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/05/2022] [Accepted: 09/10/2022] [Indexed: 11/18/2022]
Abstract
As fibrous collagen is the most abundant protein in mammalian tissues, gels of collagen fibers have been extensively used as an extracellular matrix scaffold to study how cells sense and respond to cues from their microenvironment. Other components of native tissues, such as glycosaminoglycans like hyaluronic acid, can affect cell behavior in part by changing the mechanical properties of the collagen gel. Prior studies have quantified the effects of hyaluronic acid on the mechanical properties of collagen gels in experiments of uniform shear or compression at the macroscale. However, there remains a lack of experimental studies of how hyaluronic acid changes the mechanical properties of collagen gels at the scale of a cell. Here, we studied how addition of hyaluronic acid to gels of collagen fibers affects the local field of displacements in response to contractile loads applied on length scales similar to those of a contracting cell. Using spherical poly(N-isopropylacrylamide) particles, which contract when heated, we induced displacement in gels of collagen and collagen with hyaluronic acid. Displacement fields were quantified using a combination of confocal microscopy and digital image correlation. Results showed that hyaluronic acid suppressed the distance over which displacements propagated, suggesting that it caused the network to become more linear. Additionally, hyaluronic acid had no statistical effect on heterogeneity of the displacement fields, but it did make the gels more elastic by substantially reducing the magnitude of permanent deformations. Lastly, we examined the effect of hyaluronic acid on fiber remodeling due to localized forces and found that hyaluronic acid partially - but not fully - inhibited remodeling. This result is consistent with prior studies suggesting that fiber remodeling is associated with a phase transition resulting from an instability caused by nonlinearity of the collagen gel.
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Affiliation(s)
- Maria Proestaki
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Mainak Sarkar
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian M Burkel
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, USA; University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - Suzanne M Ponik
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, USA; University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - Jacob Notbohm
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, USA; University of Wisconsin Carbone Cancer Center, Madison, WI, USA.
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10
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Carroll B, Thanh MTH, Patteson AE. Dynamic remodeling of fiber networks with stiff inclusions under compressive loading. Acta Biomater 2022; 163:106-116. [PMID: 36182057 DOI: 10.1016/j.actbio.2022.09.063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022]
Abstract
The ability of tissues to sustain and withstand mechanical stress is critical to tissue development and healthy tissue maintenance. The mechanical properties of tissues are typically considered to be dominated by the fibrous extracellular matrix (ECM) component of tissues. Fiber network mechanics can capture certain mechanical features of tissues, such as shear strain stiffening, but is insufficient in describing the compressive response of certain tissues and blood clots that are rich in extracellular matrix. To understand the mechanical response of tissues, we employ a contemporary mechanical model, a fibrous network of fibrin embedded with inert bead inclusions that preserve the volume-conserving constraints of cells in tissues. Combining bulk mechanical rheology and a custom imaging device, we show that the presence of inclusions alters the local dynamic remodeling of the networks undergoing uniaxial compressive strains and demonstrate non-affine correlated motion within a fiber-bead network, predicted to stretch fibers in the network and lead to the ability of the network to stiffen under compression, a key feature of real tissues. These findings have important implications for understanding how local structural properties of cells and ECM fibers impact the bulk mechanical response of real tissues. STATEMENT OF SIGNIFICANCE: To understand why real tissue stiffens under compression, we study a model tissue system which also stiffens: a fibrin network embedded with stiff beads. We design a device that images compression of both fiber and fiber-bead networks. Distinct from previous imaging studies, this setup can dynamically capture network deformation on scales larger than single fibers. From the videos, we see fluid flow and network remodeling are both critical to compression behavior. The fiber-bead network has faster fluid flow, reduced network recovery, and correlated motion during network relaxation. We hypothesize that the beads hinder network relaxation of stretched fibers, thus retaining the applied stress and exhibiting stiffening. Our findings reveal important details for modeling tissue mechanics towards optimizing healthcare.
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Affiliation(s)
- Bobby Carroll
- Physics Department and BioInspired Institute, Syracuse University, Physics Building, Syracuse, NY 13244, USA
| | - Minh-Tri Ho Thanh
- Physics Department and BioInspired Institute, Syracuse University, Physics Building, Syracuse, NY 13244, USA
| | - Alison E Patteson
- Physics Department and BioInspired Institute, Syracuse University, Physics Building, Syracuse, NY 13244, USA.
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11
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Sun C, Purohit PK. Rheology of fibrous gels under compression. EXTREME MECHANICS LETTERS 2022; 54:101757. [PMID: 37035476 PMCID: PMC10081149 DOI: 10.1016/j.eml.2022.101757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
A number of biological tissues and synthetic gels consist of a fibrous network infused with liquid. There have been a few experimental studies of the rheological properties of such gels under applied compressive strain. Their results suggest that a plot of rheological moduli as a function of applied compressive strain has a long plateau flanked by a steeply increasing curve for large compressive strains and a slowly decreasing curve for small strains. In this paper we explain these trends in rheological properties using a chemo-elastic model characterized by a double-well strain energy function for the underlying fibrous network. The wells correspond to rarefied and densified phases of the fibrous network at low and high strains, respectively. These phases can co-exist across a movable transition front in the gel in order to accommodate overall applied compression. We find that the rheological properties of fibrous gels share similarities with a Kelvin-Voigt visco-elastic solid. The storage modulus has its origins in the elasticity of the fibrous network, while the loss modulus is determined by the dissipation caused by liquid flow through pores. The rheological properties can depend on the number of phase transition fronts present in a compressed sample. Our analysis may explain the dependence of storage and loss moduli of fibrin gels on the loading history. We also point to the need for combining rheological measurements on gels with a microstructural analysis that could shed light on various dissipation mechanisms.
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12
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Spiewak R, Vankayalapati GS, Considine JM, Turner KT, Purohit PK. Humidity dependence of fracture toughness of cellulose fibrous networks. ENGINEERING FRACTURE MECHANICS 2022; 264:108330. [PMID: 35340366 PMCID: PMC8953284 DOI: 10.1016/j.engfracmech.2022.108330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cellulose-based materials are increasingly finding applications in technology due to their sustainability and biodegradability. The sensitivity of cellulose fiber networks to environmental conditions such as temperature and humidity is well known. Yet, there is an incomplete understanding of the dependence of the fracture toughness of cellulose networks on environmental conditions. In the current study, we assess the effect of moisture content on the out-of-plane (i.e., z-dir.) fracture toughness of a particular cellulose network, specifically Whatman cellulose filter paper. Experimental measurements are performed at 16% RH along the desorption isotherm and 23, 37, 50, 75% RH along the adsorption isotherm using out-of-plane tensile tests and double cantilever beam (DCB) tests. Cohesive zone modeling and finite element simulations are used to extract quantitative properties that describe the crack growth behavior. Overall, the fracture toughness of filter paper decreased with increasing humidity. Additionally, a novel model is developed to capture the high peak and sudden drop in the experimental force measurement caused by the existence of an initiation region. This model is found to be in good agreement with experimental data. The relative effect of each independent cohesive parameter is explored to better understand the cohesive zone-based humidity dependence model. The methods described here may be applied to study rupture of other fiber networks with weak bonds.
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Affiliation(s)
- Russell Spiewak
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gnana Saurya Vankayalapati
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Kevin T. Turner
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Prashant K. Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
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Pancaldi F, Kim OV, Weisel JW, Alber M, Xu Z. Computational Biomechanical Modeling of Fibrin Networks and Platelet-Fiber Network Interactions. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2022; 22. [DOI: 10.1016/j.cobme.2022.100369] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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Cahalane R, Boodt N, Akyildiz AC, Giezen JA, Mondeel M, van der Lugt A, Marquering H, Gijsen F. A review on the association of thrombus composition with mechanical and radiological imaging characteristics in acute ischemic stroke. J Biomech 2021; 129:110816. [PMID: 34798567 DOI: 10.1016/j.jbiomech.2021.110816] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 02/05/2023]
Abstract
Thrombus composition and mechanical properties significantly impact the ease and outcomes of thrombectomy procedures in patients with acute ischemic stroke. A wide variation exists in the composition of thrombi between patients. If a relationship can be determined between the composition of a thrombus and its mechanical behaviour, as well as between the composition of a thrombus and its radiological imaging characteristics, then there is the potential to personalise thrombectomy treatment based on each individual thrombus. This review aims to give an overview of the current literature addressing this issue. Here, we present a scoping review detailing associations between thrombus composition, mechanical behaviour and radiological imaging characteristics. We conducted two searches 1) on the association between thrombus composition and the mechanical behaviour of the tissue and 2) on the association between radiological imaging characteristics and thrombus composition in the acute stroke setting. The review suggests that higher fibrin and lower red blood cell (RBC) content contribute to stiffer thrombi independent of the loading mode. Further, platelet-contracted thrombi are stiffer than non-contracted compositional counterparts. Fibrin content contributes to the elastic portion of viscoelastic behaviour while RBC content contributes to the viscous portion. It is possible to identify fibrin-rich or RBC-rich thrombi with computed tomography and magnetic resonance imaging vessel signs. Standardisation is required to quantify the association between thrombus density on non-contrast computed tomography and the RBC content. The characterisation of the thrombus fibrin network has not been addressed so far in radiological imaging but may be essential for the prediction of device-tissue interactions and distal thrombus embolization. The association between platelet-driven clot contraction and radiological imaging characteristics has not been explicitly investigated. However, evidence suggests that perviousness may be a marker of clot contraction.
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Affiliation(s)
- Rachel Cahalane
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Nikki Boodt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Neurology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Ali Cagdas Akyildiz
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands
| | - Jo-Anne Giezen
- Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands
| | - Manouk Mondeel
- Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Henk Marquering
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Frank Gijsen
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands.
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Sun C, Chernysh IN, Weisel JW, Purohit PK. Fibrous gels modelled as fluid-filled continua with double-well energy landscape. Proc Math Phys Eng Sci 2021; 476:20200643. [PMID: 33408566 DOI: 10.1098/rspa.2020.0643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 11/11/2020] [Indexed: 01/09/2023] Open
Abstract
Several biological materials are fibre networks infused with fluid, often referred to as fibrous gels. An important feature of these gels is that the fibres buckle under compression, causing a densification of the network that is accompanied by a reduction in volume and release of fluid. Displacement-controlled compression of fibrous gels has shown that the network can exist in a rarefied and a densified state over a range of stresses. Continuum chemo-elastic theories can be used to model the mechanical behaviour of these gels, but they suffer from the drawback that the stored energy function of the underlying network is based on neo-Hookean elasticity, which cannot account for the existence of multiple phases. Here we use a double-well stored energy function in a chemo-elastic model of gels to capture the existence of two phases of the network. We model cyclic compression/decompression experiments on fibrous gels and show that they exhibit propagating interfaces and hysteretic stress-strain curves that have been observed in experiments. We can capture features in the rate-dependent response of these fibrous gels without recourse to finite-element calculations. We also perform experiments to show that certain features in the stress-strain curves of fibrous gels predicted by our model can be found in the compression response of blood clots. Our methods may be extended to other tissues and synthetic gels that have a fibrous structure.
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Affiliation(s)
- Chuanpeng Sun
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Irina N Chernysh
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John W Weisel
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Prashant K Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
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Abstract
Fibrinogen is a large glycoprotein, synthesized primarily in the liver. With a normal plasma concentration of 1.5-3.5 g/L, fibrinogen is the most abundant blood coagulation factor. The final stage of blood clot formation is the conversion of soluble fibrinogen to insoluble fibrin, the polymeric scaffold for blood clots that stop bleeding (a protective reaction called hemostasis) or obstruct blood vessels (pathological thrombosis). Fibrin is a viscoelastic polymer and the structural and mechanical properties of the fibrin scaffold determine its effectiveness in hemostasis and the development and outcome of thrombotic complications. Fibrin polymerization comprises a number of consecutive reactions, each affecting the ultimate 3D porous network structure. The physical properties of fibrin clots are determined by structural features at the individual fibrin molecule, fibrin fiber, network, and whole clot levels and are among the most important functional characteristics, enabling the blood clot to withstand arterial blood flow, platelet-driven clot contraction, and other dynamic forces. This chapter describes the molecular structure of fibrinogen, the conversion of fibrinogen to fibrin, the mechanical properties of fibrin as well as its structural origins and lastly provides evidence for the role of altered fibrin clot properties in both thrombosis and bleeding.
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Tutwiler V, Singh J, Litvinov RI, Bassani JL, Purohit PK, Weisel JW. Rupture of blood clots: Mechanics and pathophysiology. SCIENCE ADVANCES 2020; 6:eabc0496. [PMID: 32923647 PMCID: PMC7449685 DOI: 10.1126/sciadv.abc0496] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/02/2020] [Indexed: 05/07/2023]
Abstract
Fibrin is the three-dimensional mechanical scaffold of protective blood clots that stop bleeding and pathological thrombi that obstruct blood vessels. Fibrin must be mechanically tough to withstand rupture, after which life-threatening pieces (thrombotic emboli) are carried downstream by blood flow. Despite multiple studies on fibrin viscoelasticity, mechanisms of fibrin rupture remain unknown. Here, we examined mechanically and structurally the strain-driven rupture of human blood plasma-derived fibrin clots where clotting was triggered with tissue factor. Toughness, i.e., resistance to rupture, quantified by the critical energy release rate (a measure of the propensity for clot embolization) of physiologically relevant fibrin gels was determined to be 7.6 ± 0.45 J/m2. Finite element (FE) simulations using fibrin material models that account for forced protein unfolding independently supported this measured toughness and showed that breaking of fibers ahead the crack at a critical stretch is the mechanism of rupture of blood clots, including thrombotic embolization.
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Affiliation(s)
- Valerie Tutwiler
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jaspreet Singh
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA
| | - Rustem I. Litvinov
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation
| | - John L. Bassani
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA
| | - Prashant K. Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA
| | - John W. Weisel
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
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Chernysh IN, Spiewak R, Cambor CL, Purohit PK, Weisel JW. Structure, mechanical properties, and modeling of cyclically compressed pulmonary emboli. J Mech Behav Biomed Mater 2020; 105:103699. [PMID: 32279846 DOI: 10.1016/j.jmbbm.2020.103699] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 12/15/2022]
Abstract
Pulmonary embolism occurs when blood flow to a part of the lungs is blocked by a venous thrombus that has traveled from the lower limbs. Little is known about the mechanical behavior of emboli under compressive forces from the surrounding musculature and blood pressure. We measured the stress-strain responses of human pulmonary emboli under cyclic compression, and showed that emboli exhibit a hysteretic stress-strain curve. The fibrin fibers and red blood cells (RBCs) are damaged during the compression process, causing irreversible changes in the structure of the emboli. We showed using electron and confocal microscopy that bundling of fibrin fibers occurs due to compression, and damage is accumulated as more cycles are applied. The stress-strain curves depend on embolus structure, such that variations in composition give quantitatively different responses. Emboli with a high fibrin component demonstrate higher normal stress compared to emboli that have a high RBC component. We compared the compression response of emboli to that of whole blood clots containing various volume fractions of RBCs, and found that RBCs rupture at a certain critical stress. We describe the hysteretic response characteristic of foams, using a model of phase transitions in which the compressed foam is segregated into coexisting rarefied and densified phases whose fractions change during compression. Our model takes account of the rupture of RBCs in the compressed emboli and stresses due to fluid flow through their small pores. Our results can help in classifying emboli as rich in fibrin or rich in red blood cells, and can help in understanding what responses to expect when stresses are applied to thrombi in vivo.
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Affiliation(s)
- Irina N Chernysh
- Department of Cell Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Russell Spiewak
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Carolyn L Cambor
- Department of Pathology and Laboratory of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Prashant K Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - John W Weisel
- Department of Cell Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Britton S, Kim O, Pancaldi F, Xu Z, Litvinov RI, Weisel JW, Alber M. Contribution of nascent cohesive fiber-fiber interactions to the non-linear elasticity of fibrin networks under tensile load. Acta Biomater 2019; 94:514-523. [PMID: 31152942 PMCID: PMC6907156 DOI: 10.1016/j.actbio.2019.05.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/21/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Abstract
Fibrin is a viscoelastic proteinaceous polymer that determines the deformability and integrity of blood clots and fibrin-based biomaterials in response to biomechanical forces. Here, a previously unnoticed structural mechanism of fibrin clots' mechanical response to external tensile loads is tested using high-resolution confocal microscopy and recently developed three-dimensional computational model. This mechanism, underlying local strain-stiffening of individual fibers as well as global stiffening of the entire network, is based on previously neglected nascent cohesive pairwise interactions between individual fibers (crisscrossing) in fibrin networks formed under tensile load. Existence of fiber-fiber crisscrossings of reoriented fibers was confirmed using 3D imaging of experimentally obtained stretched fibrin clots. The computational model enabled us to study structural details and quantify mechanical effects of the fiber-fiber cohesive crisscrossing during stretching of fibrin gels at various spatial scales. The contribution of the fiber-fiber cohesive contacts to the elasticity of stretched fibrin networks was characterized by changes in individual fiber stiffness, the length, width, and alignment of fibers, as well as connectivity and density of the entire network. The results show that the nascent cohesive crisscrossing of fibers in stretched fibrin networks comprise an underappreciated important structural mechanism underlying the mechanical response of fibrin to (patho)physiological stresses that determine the course and outcomes of thrombotic and hemostatic disorders, such as heart attack and ischemic stroke. STATEMENT OF SIGNIFICANCE: Fibrin is a viscoelastic proteinaceous polymer that determines the deformability and integrity of blood clots and fibrin-based biomaterials in response to biomechanical forces. In this paper, a novel structural mechanism of fibrin clots' mechanical response to external tensile loads is tested using high-resolution confocal microscopy and newly developed computational model. This mechanism, underlying local strain-stiffening of individual fibers as well as global stiffening of the entire network, is based on previously neglected nascent cohesive pairwise interactions between individual fibers (crisscrossing) in fibrin networks formed under tensile load. Cohesive crisscrossing is an important structural mechanism that influences the mechanical response of blood clots and which can determine the outcomes of blood coagulation disorders, such as heart attacks and strokes.
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Affiliation(s)
- Samuel Britton
- Department of Mathematics, University of California Riverside, Riverside, CA 92505, USA; Center for Quantitative Modeling in Biology, University of California Riverside, Riverside, CA 92505, USA
| | - Oleg Kim
- Department of Mathematics, University of California Riverside, Riverside, CA 92505, USA; Center for Quantitative Modeling in Biology, University of California Riverside, Riverside, CA 92505, USA; Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Francesco Pancaldi
- Department of Mathematics, University of California Riverside, Riverside, CA 92505, USA; Center for Quantitative Modeling in Biology, University of California Riverside, Riverside, CA 92505, USA
| | - Zhiliang Xu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, IN 46556, USA
| | - Rustem I Litvinov
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA; Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420012, Russian Federation
| | - John W Weisel
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
| | - Mark Alber
- Department of Mathematics, University of California Riverside, Riverside, CA 92505, USA; Center for Quantitative Modeling in Biology, University of California Riverside, Riverside, CA 92505, USA.
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Modeling thrombosis in silico: Frontiers, challenges, unresolved problems and milestones. Phys Life Rev 2018; 26-27:57-95. [PMID: 29550179 DOI: 10.1016/j.plrev.2018.02.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/21/2018] [Accepted: 02/24/2018] [Indexed: 12/24/2022]
Abstract
Hemostasis is a complex physiological mechanism that functions to maintain vascular integrity under any conditions. Its primary components are blood platelets and a coagulation network that interact to form the hemostatic plug, a combination of cell aggregate and gelatinous fibrin clot that stops bleeding upon vascular injury. Disorders of hemostasis result in bleeding or thrombosis, and are the major immediate cause of mortality and morbidity in the world. Regulation of hemostasis and thrombosis is immensely complex, as it depends on blood cell adhesion and mechanics, hydrodynamics and mass transport of various species, huge signal transduction networks in platelets, as well as spatiotemporal regulation of the blood coagulation network. Mathematical and computational modeling has been increasingly used to gain insight into this complexity over the last 30 years, but the limitations of the existing models remain profound. Here we review state-of-the-art-methods for computational modeling of thrombosis with the specific focus on the analysis of unresolved challenges. They include: a) fundamental issues related to physics of platelet aggregates and fibrin gels; b) computational challenges and limitations for solution of the models that combine cell adhesion, hydrodynamics and chemistry; c) biological mysteries and unknown parameters of processes; d) biophysical complexities of the spatiotemporal networks' regulation. Both relatively classical approaches and innovative computational techniques for their solution are considered; the subjects discussed with relation to thrombosis modeling include coarse-graining, continuum versus particle-based modeling, multiscale models, hybrid models, parameter estimation and others. Fundamental understanding gained from theoretical models are highlighted and a description of future prospects in the field and the nearest possible aims are given.
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