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Rao C, Lin W, Song Z. Analytical refractory period distribution for a class of time-variant biochemical systems with second-order reactions. J Chem Phys 2023; 159:124105. [PMID: 38127379 DOI: 10.1063/5.0156276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/05/2023] [Indexed: 12/23/2023] Open
Abstract
Refractory period (RP), the waiting time between signals, can induce complex signaling dynamics, such as acceleration, adaptation, and oscillation, within many cellular biochemical networks. However, its underlying molecular mechanisms are still unclear. Rigorously estimating the RP distribution may be essential to identify its causal regulatory mechanisms. Traditional methods of estimating the RP distribution depend on solving the underlying Chemical Master Equations (CMEs), the dominant modeling formalism of biochemical systems. However, exact solutions of the CME are only known for simple reaction systems with zero- and first-order reactions or specific systems with second-order reactions. General solutions still need to be derived for systems with bimolecular reactions. It is even more challenging if large state-space and nonconstant reaction rates are involved. Here, we developed a direct method to gain the analytical RP distribution for a class of second-order reaction systems with nonconstant reaction rates and large state space. Instead of using the CME, we used an equivalent path-wise representation, which is the solution to a transformed martingale problem of the CME. This allowed us to bypass solving a CME. We then applied the method to derive the analytical RP distribution of a real complex biochemical network with second-order reactions, the Drosophila phototransduction cascade. Our approach provides an alternative to the CMEs in deriving the analytical RP distributions of a class of second-order reaction systems. Since the bimolecular reactions are common in biological systems, our approach could enhance understanding real-world biochemical processes.
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Affiliation(s)
- Changqian Rao
- School of Mathematical Sciences and Shanghai Center for Mathematical Sciences, Fudan University, 200433 Shanghai, China
- Research Institute of Intelligent Complex Systems, Fudan University, 200433 Shanghai, China
| | - Wei Lin
- School of Mathematical Sciences and Shanghai Center for Mathematical Sciences, Fudan University, 200433 Shanghai, China
- Research Institute of Intelligent Complex Systems, Fudan University, 200433 Shanghai, China
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, 200433 Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Brain Science, Fudan University, 200032 Shanghai, China
| | - Zhuoyi Song
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, 200433 Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Brain Science, Fudan University, 200032 Shanghai, China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Shanghai, China
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Abstract
When animals walk overground, mechanical stimuli activate various receptors located in muscles, joints, and skin. Afferents from these mechanoreceptors project to neuronal networks controlling locomotion in the spinal cord and brain. The dynamic interactions between the control systems at different levels of the neuraxis ensure that locomotion adjusts to its environment and meets task demands. In this article, we describe and discuss the essential contribution of somatosensory feedback to locomotion. We start with a discussion of how biomechanical properties of the body affect somatosensory feedback. We follow with the different types of mechanoreceptors and somatosensory afferents and their activity during locomotion. We then describe central projections to locomotor networks and the modulation of somatosensory feedback during locomotion and its mechanisms. We then discuss experimental approaches and animal models used to investigate the control of locomotion by somatosensory feedback before providing an overview of the different functional roles of somatosensory feedback for locomotion. Lastly, we briefly describe the role of somatosensory feedback in the recovery of locomotion after neurological injury. We highlight the fact that somatosensory feedback is an essential component of a highly integrated system for locomotor control. © 2021 American Physiological Society. Compr Physiol 11:1-71, 2021.
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Affiliation(s)
- Alain Frigon
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Quebec, Canada
| | - Turgay Akay
- Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Boris I Prilutsky
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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Song Z, Zhou Y, Feng J, Juusola M. Multiscale 'whole-cell' models to study neural information processing - New insights from fly photoreceptor studies. J Neurosci Methods 2021; 357:109156. [PMID: 33775669 DOI: 10.1016/j.jneumeth.2021.109156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 11/26/2022]
Abstract
Understanding a neuron's input-output relationship is a longstanding challenge. Arguably, these signalling dynamics can be better understood if studied at three levels of analysis: computational, algorithmic and implementational (Marr, 1982). But it is difficult to integrate such analyses into a single platform that can realistically simulate neural information processing. Multiscale dynamical "whole-cell" modelling, a recent systems biology approach, makes this possible. Dynamical "whole-cell" models are computational models that aim to account for the integrated function of numerous genes or molecules to behave like virtual cells in silico. However, because constructing such models is laborious, only a couple of examples have emerged since the first one, built for Mycoplasma genitalium bacterium, was reported in 2012. Here, we review dynamic "whole-cell" neuron models for fly photoreceptors and how these have been used to study neural information processing. Specifically, we review how the models have helped uncover the mechanisms and evolutionary rules of quantal light information sampling and integration, which underlie light adaptation and further improve our understanding of insect vision.
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Affiliation(s)
- Zhuoyi Song
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200433, China; Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, China; MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Shanghai, China.
| | - Yu Zhou
- School of Computing, Engineering and Physical Sciences, University of Central Lancashire, Preston PR1 2HE, UK
| | - Jianfeng Feng
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200433, China; Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, China; MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Shanghai, China
| | - Mikko Juusola
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK; State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China.
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Exposure to Sustained Flexion Impacts Lumbar Extensor Spinae Muscle Fiber Orientation. J Appl Biomech 2021; 37:248-253. [PMID: 33631717 DOI: 10.1123/jab.2020-0238] [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: 07/24/2020] [Revised: 11/25/2020] [Accepted: 01/08/2021] [Indexed: 11/18/2022]
Abstract
The lumbar extensor spinae (LES) has an oblique orientation with respect to the compressive axis of the lumbar spine, allowing it to counteract anterior shear forces. This mechanical advantage is lost as spine flexion angle increases. The LES orientation can also alter over time as obliquity decreases with age and is associated with decreased strength and low back pain. However, it is unknown if LES orientation is impacted by recent exposures causing adaptations over shorter timescales. Hence, the effects of a 10-minute sustained spine flexion exposure on LES orientation, thickness, and activity were investigated. Three different submaximally flexed spine postures were observed before and after the exposure. At baseline, orientation (P < .001) and thickness (P = .004) decreased with increasingly flexed postures. After the exposure, obliquity further decreased at low (pairwise comparison P < .001) and moderately (pairwise comparison P = .008) flexed postures. Low back creep occurred, but LES thickness did not change, indicating that decreases in orientation were not solely due to changes in muscle length at a given posture. Activation did not change to counteract decreases in obliquity. These changes encompass a reduced ability to offset anterior shear forces, thus increasing the potential risk of anterior shear-related injury or pain after low back creep-generating exposures.
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Blum KP, Campbell KS, Horslen BC, Nardelli P, Housley SN, Cope TC, Ting LH. Diverse and complex muscle spindle afferent firing properties emerge from multiscale muscle mechanics. eLife 2020; 9:e55177. [PMID: 33370235 PMCID: PMC7769569 DOI: 10.7554/elife.55177] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 12/04/2020] [Indexed: 11/13/2022] Open
Abstract
Despite decades of research, we lack a mechanistic framework capable of predicting how movement-related signals are transformed into the diversity of muscle spindle afferent firing patterns observed experimentally, particularly in naturalistic behaviors. Here, a biophysical model demonstrates that well-known firing characteristics of mammalian muscle spindle Ia afferents - including movement history dependence, and nonlinear scaling with muscle stretch velocity - emerge from first principles of muscle contractile mechanics. Further, mechanical interactions of the muscle spindle with muscle-tendon dynamics reveal how motor commands to the muscle (alpha drive) versus muscle spindle (gamma drive) can cause highly variable and complex activity during active muscle contraction and muscle stretch that defy simple explanation. Depending on the neuromechanical conditions, the muscle spindle model output appears to 'encode' aspects of muscle force, yank, length, stiffness, velocity, and/or acceleration, providing an extendable, multiscale, biophysical framework for understanding and predicting proprioceptive sensory signals in health and disease.
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Affiliation(s)
- Kyle P Blum
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
| | | | - Brian C Horslen
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
| | - Paul Nardelli
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Stephen N Housley
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Timothy C Cope
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
- School of Biological Sciences, Georgia Institute of TechnologyAtlantaUnited States
| | - Lena H Ting
- Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of TechnologyAtlantaUnited States
- Department of Rehabilitation Medicine, Emory UniversityAtlantaUnited States
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T 1ρ-Mapping for Musculoskeletal Pain Diagnosis: Case Series of Variation of Water Bound Glycosaminoglycans Quantification before and after Fascial Manipulation ® in Subjects with Elbow Pain. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030708. [PMID: 31979044 PMCID: PMC7037807 DOI: 10.3390/ijerph17030708] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/18/2020] [Accepted: 01/19/2020] [Indexed: 12/16/2022]
Abstract
Diagnosis and management of musculoskeletal pain is a major clinical challenge. Following this need, the first aim of our study was to provide an innovative magnetic resonance technique called T1ρ to quantify possible alterations in elbow pain, a common musculoskeletal pain syndrome that has not a clear etiology. Five patients were recruited presenting chronic elbow pain (>3 months), with an age between 30 and 70 years old. Patients underwent two T1ρ-mapping evaluations, one before and one after the series of Fascial Manipulation® (FM) treatments. After the first MRI evaluation, a Disability of the Arm, Shoulder and Hand (DASH) questionnaire was administered to quantify the symptoms and pain intensity. Patients then received three sessions of FM, once a week for 40 min each. A statistically significant difference was found between bound and unbound water concentration before and after FM treatment. Our preliminary data suggest that the application of the manual method seems to decrease the concentration of unbound water inside the deep fascia in the most chronic patients. This could explain the change in viscosity perceived by many practitioners as well as the decrease of symptoms due to the restoration of the normal property of the loose connective tissue. Being able to identify an altered deep fascial area may better guide therapies, contributing to a more nuanced view of the mechanisms of pain.
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Song Z, Zhou Y, Juusola M. Modeling elucidates how refractory period can provide profound nonlinear gain control to graded potential neurons. Physiol Rep 2018; 5:5/11/e13306. [PMID: 28596301 PMCID: PMC5471445 DOI: 10.14814/phy2.13306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/02/2017] [Accepted: 05/04/2017] [Indexed: 11/24/2022] Open
Abstract
Refractory period (RP) plays a central role in neural signaling. Because it limits an excitable membrane's recovery time from a previous excitation, it can restrict information transmission. Classically, RP means the recovery time from an action potential (spike), and its impact to encoding has been mostly studied in spiking neurons. However, many sensory neurons do not communicate with spikes but convey information by graded potential changes. In these systems, RP can arise as an intrinsic property of their quantal micro/nanodomain sampling events, as recently revealed for quantum bumps (single photon responses) in microvillar photoreceptors. Whilst RP is directly unobservable and hard to measure, masked by the graded macroscopic response that integrates numerous quantal events, modeling can uncover its role in encoding. Here, we investigate computationally how RP can affect encoding of graded neural responses. Simulations in a simple stochastic process model for a fly photoreceptor elucidate how RP can profoundly contribute to nonlinear gain control to achieve a large dynamic range.
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Affiliation(s)
- Zhuoyi Song
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Yu Zhou
- School of Engineering University of Central Lancashire, Preston, United Kingdom
| | - Mikko Juusola
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom .,State Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University, Beijing, China
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Song Z, Juusola M. A biomimetic fly photoreceptor model elucidates how stochastic adaptive quantal sampling provides a large dynamic range. J Physiol 2017; 595:5439-5456. [PMID: 28369994 PMCID: PMC5556150 DOI: 10.1113/jp273614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/10/2017] [Indexed: 11/08/2022] Open
Abstract
Light intensities (photons s-1 μm-2 ) in a natural scene vary over several orders of magnitude from shady woods to direct sunlight. A major challenge facing the visual system is how to map such a large dynamic input range into its limited output range, so that a signal is neither buried in noise in darkness nor saturated in brightness. A fly photoreceptor has achieved such a large dynamic range; it can encode intensity changes from single to billions of photons, outperforming man-made light sensors. This performance requires powerful light adaptation, the neural implementation of which has only become clear recently. A computational fly photoreceptor model, which mimics the real phototransduction processes, has elucidated how light adaptation happens dynamically through stochastic adaptive quantal information sampling. A Drosophila R1-R6 photoreceptor's light sensor, the rhabdomere, has 30,000 microvilli, each of which stochastically samples incoming photons. Each microvillus employs a full G-protein-coupled receptor signalling pathway to adaptively transduce photons into quantum bumps (QBs, or samples). QBs then sum the macroscopic photoreceptor responses, governed by four quantal sampling factors (limitations): (i) the number of photon sampling units in the cell structure (microvilli), (ii) sample size (QB waveform), (iii) latency distribution (time delay between photon arrival and emergence of a QB), and (iv) refractory period distribution (time for a microvillus to recover after a QB). Here, we review how these factors jointly orchestrate light adaptation over a large dynamic range.
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Affiliation(s)
- Zhuoyi Song
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Mikko Juusola
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK.,State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
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Pintucci M, Simis M, Imamura M, Pratelli E, Stecco A, Ozcakar L, Battistella LR. Successful treatment of rotator cuff tear using Fascial Manipulation ® in a stroke patient. J Bodyw Mov Ther 2016; 21:653-657. [PMID: 28750980 DOI: 10.1016/j.jbmt.2016.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 12/12/2016] [Accepted: 12/15/2016] [Indexed: 10/20/2022]
Abstract
Rotator cuff tear is a common disease affecting patients after stroke. It's a cause of pain and dysfunction that may compromise normal stroke rehabilitation. For many cases there is still controversy between whether to use surgical or conservative intervention. Treatment for cuff tears range from physical therapy to surgery. This paper describes for the first time the effect of Fascial Manipulation® (FM®) on rotator cuff tear in a post stroke patient. A 69 year old female stroke patient with full absence of distal components of the tendons of the rotator cuff, functional limitations on active movement of shoulder flexion and abduction of the left arm and perceived pain scored 10/10 on the Visual Analogic Scale, was assessed and treat with one session of FM® A basic theory that explains the healing results of FM® is that mechanoreceptors, such as spindle cells and other receptors, are located in the deep fascia and activated when movement are performed. Increased viscosity of the deep fascia and muscles due to increased viscosity of hyaluronic acid (HA) molecules prevents the normal gliding of fascia during movement inhibiting normal proprioception and muscle function.
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Affiliation(s)
- Marco Pintucci
- Institute of Physical and Rehabilitation Medicine, Sao Paulo, Brazil
| | - Marcel Simis
- Institute of Physical and Rehabilitation Medicine, Sao Paulo, Brazil
| | - Marta Imamura
- Institute of Physical and Rehabilitation Medicine, Sao Paulo, Brazil
| | - Elisa Pratelli
- Neuro-Muscular-Skeletal Department, Rehabilitation Unit, University Hospital Careggi, Florence, Italy
| | - Antonio Stecco
- Rusk Rehabilitation, New York University School of Medicine, New York City, USA.
| | - Levent Ozcakar
- Department of Physical and Rehabilitation Medicine, Hacettepe University Medical School, Ankara, Turkey
| | - Linamara Rizzo Battistella
- Institute of Physical Medicine and Rehabilitation, General Hospital, Medical College, University of São Paulo, Sao Paulo, Brazil
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Branchini M, Lopopolo F, Andreoli E, Loreti I, Marchand AM, Stecco A. Fascial Manipulation® for chronic aspecific low back pain: a single blinded randomized controlled trial. F1000Res 2015; 4:1208. [PMID: 26834998 PMCID: PMC4706049 DOI: 10.12688/f1000research.6890.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/06/2016] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND The therapeutic approach to chronic aspecific low back pain (CALBP) has to consider the multifactorial aetiology of the disorder. International guidelines do not agree on unequivocal treatment indications. Recommendations for fascial therapy are few and of low level evidence but several studies indicate strong correlations between fascial thickness and low back pain. This study aims at comparing the effectiveness of Fascial Manipulation® associated with a physiotherapy program following guidelines for CALBP compared to a physiotherapy program alone. METHODS 24 subjects were randomized into two groups, both received eight treatments over 4 weeks. Outcomes were measured at baseline, at the end of therapy and at a 1 month and a 3 months follow-up. Pain was measured with the visual analogue scale (VAS) and the brief pain inventory (BPI), function with the Rolland-Morris disability questionnaire (RMDQ), state of well-being with the short-form 36 health-survey (SF-36). The mean clinical important difference (MCID) was also measured. RESULTS Patients receiving Fascial Manipulation® showed statistically and clinically significant improvements at the end of care for all outcomes, in the short (RMDQ, VAS, BPI) and medium term for VAS and BPI compared to manual therapy. The MCID show significant improvements in the means and percentage of subjects in groups in all outcomes post-treatment, in the short and medium term. CONCLUSION Fascial tissues were implicated in the aetiology of CALBP and treatment led to decreased symptomatic, improved functional and perceived well-being outcomes that were of greater amplitude compared to manual therapy alone.
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Affiliation(s)
- Mirco Branchini
- Physiotherapy Academic Program, University of Bologna, Bologna, 40138, Italy
| | | | - Ernesto Andreoli
- Department of Continuity Assistance and Disability, University of Bologna, Bologna, 40138, Italy
| | - Ivano Loreti
- Department of Emergency, University of Bologna, Bologna, 40138, Italy
| | | | - Antonio Stecco
- Sports Medicine Unit, University of Padua, Padova, 35120, Italy
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Branchini M, Lopopolo F, Andreoli E, Loreti I, Marchand AM, Stecco A. Fascial Manipulation® for chronic aspecific low back pain: a single blinded randomized controlled trial. F1000Res 2015; 4:1208. [PMID: 26834998 PMCID: PMC4706049 DOI: 10.12688/f1000research.6890.2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/06/2016] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The therapeutic approach to chronic aspecific low back pain (CALBP) has to consider the multifactorial aetiology of the disorder. International guidelines do not agree on unequivocal treatment indications. Recommendations for fascial therapy are few and of low level evidence but several studies indicate strong correlations between fascial thickness and low back pain. This study aims at comparing the effectiveness of Fascial Manipulation® associated with a physiotherapy program following guidelines for CALBP compared to a physiotherapy program alone. METHODS 24 subjects were randomized into two groups, both received eight treatments over 4 weeks. Outcomes were measured at baseline, at the end of therapy and at a 1 month and a 3 months follow-up. Pain was measured with the visual analogue scale (VAS) and the brief pain inventory (BPI), function with the Rolland-Morris disability questionnaire (RMDQ), state of well-being with the short-form 36 health-survey (SF-36). The mean clinical important difference (MCID) was also measured. RESULTS Patients receiving Fascial Manipulation® showed statistically and clinically significant improvements at the end of care for all outcomes, in the short (RMDQ, VAS, BPI) and medium term for VAS and BPI compared to manual therapy. The MCID show significant improvements in the means and percentage of subjects in groups in all outcomes post-treatment, in the short and medium term. CONCLUSION Fascial tissues were implicated in the aetiology of CALBP and treatment led to decreased symptomatic, improved functional and perceived well-being outcomes that were of greater amplitude compared to manual therapy alone.
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Affiliation(s)
- Mirco Branchini
- Physiotherapy Academic Program, University of Bologna, Bologna, 40138, Italy
| | | | - Ernesto Andreoli
- Department of Continuity Assistance and Disability, University of Bologna, Bologna, 40138, Italy
| | - Ivano Loreti
- Department of Emergency, University of Bologna, Bologna, 40138, Italy
| | | | - Antonio Stecco
- Sports Medicine Unit, University of Padua, Padova, 35120, Italy
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Cowman MK, Schmidt TA, Raghavan P, Stecco A. Viscoelastic Properties of Hyaluronan in Physiological Conditions. F1000Res 2015; 4:622. [PMID: 26594344 PMCID: PMC4648226 DOI: 10.12688/f1000research.6885.1] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/17/2015] [Indexed: 02/01/2023] Open
Abstract
Hyaluronan (HA) is a high molecular weight glycosaminoglycan of the extracellular matrix (ECM), which is particularly abundant in soft connective tissues. Solutions of HA can be highly viscous with non-Newtonian flow properties. These properties affect the movement of HA-containing fluid layers within and underlying the deep fascia. Changes in the concentration, molecular weight, or even covalent modification of HA in inflammatory conditions, as well as changes in binding interactions with other macromolecules, can have dramatic effects on the sliding movement of fascia. The high molecular weight and the semi-flexible chain of HA are key factors leading to the high viscosity of dilute solutions, and real HA solutions show additional nonideality and greatly increased viscosity due to mutual macromolecular crowding. The shear rate dependence of the viscosity, and the viscoelasticity of HA solutions, depend on the relaxation time of the molecule, which in turn depends on the HA concentration and molecular weight. Temperature can also have an effect on these properties. High viscosity can additionally affect the lubricating function of HA solutions. Immobility can increase the concentration of HA, increase the viscosity, and reduce lubrication and gliding of the layers of connective tissue and muscle. Over time, these changes can alter both muscle structure and function. Inflammation can further increase the viscosity of HA-containing fluids if the HA is modified via covalent attachment of heavy chains derived from Inter-α-Inhibitor. Hyaluronidase hydrolyzes HA, thus reducing its molecular weight, lowering the viscosity of the extracellular matrix fluid and making outflow easier. It can also disrupt any aggregates or gel-like structures that result from HA being modified. Hyaluronidase is used medically primarily as a dispersion agent, but may also be useful in conditions where altered viscosity of the fascia is desired, such as in the treatment of muscle stiffness.
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Affiliation(s)
- Mary K Cowman
- Biomatrix Research Center, Department of Chemical and Biomolecular Engineering, Polytechnic School of Engineering, New York University, New York, NY, 10010, USA
| | - Tannin A Schmidt
- Faculty of Kinesiology & Schulich School of Engineering - Centre for Bioengineering Research & Education, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Preeti Raghavan
- Department of Rehabilitation Medicine, Rusk Rehabilitation, New York University School of Medicine, New York, NY, 10016, USA
| | - Antonio Stecco
- Department of Internal Medicine, University of Padova, Padua, 35100, Italy
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