Elucidation of extracellular matrix mechanics from muscle fibers and fiber bundles.
TL;DR: A new method to quantify viscoelastic ECM modulus is presented by combining tests of single muscle fibers and fiber bundles, which demonstrate that ECM is a highly nonlinearly elastic material, while muscle fibers are linearly elastic.
About: This article is published in Journal of Biomechanics.The article was published on 2011-02-24 and is currently open access. It has received 156 citations till now. The article focuses on the topics: Skeletal muscle.
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TL;DR: An enhanced version of the previously engineered MyoRobot system for reliable, versatile and automated investigations of skeletal muscle or linear polymer material (bio)mechanics is presented and temperature-dependent myofibrillar Ca2+ sensitivity, passive axial compliance and Young's modulus are assessed.
8 citations
TL;DR: The organizers hope to hold the 2021 Padua Days on Myology and Mobility Medicine in a semi-virtual form (2021 S-V PDM3) from May 26 to May 29 at the Thermae of Euganean Hills, Padova, Italy.
Abstract: On 19-21 November 2020, the meeting of the 30 years of the Padova Muscle Days was virtually held while the SARS-CoV-2 epidemic was hitting the world after a seemingly quiet summer. During the 2020-2021 winter, the epidemic is still active, despite the start of vaccinations. The organizers hope to hold the 2021 Padua Days on Myology and Mobility Medicine in a semi-virtual form (2021 S-V PDM3) from May 26 to May 29 at the Thermae of Euganean Hills, Padova, Italy. Here the program and the Collection of Abstracts are presented. Despite numerous world problems, the number of submitted/selected presentations (lectures and oral presentations) has increased, prompting the organizers to extend the program to four dense days.
8 citations
01 Jan 2013
TL;DR: In this article, De Bruin onderzocht welke veranderingen in het spierskelet-systeem bepalend zijn voor de typische bewegingsbeperkingen van de hand and arm bij CP.
Abstract: Patienten met een spastische arm als gevolg van halfzijdige hersenverlamming (cerebrale parese oftewel CP), kunnen beter worden geholpen als precies bekend is waar in de arm de behandeling moet beginnen. De kennis van mechanica van de weefsels in de arm en interacties tussen botten, spieren en pezen is onvoldoende, blijkt uit het onderzoek van Marije de Bruin naar patienten bij wie voor het eerste levensjaar CP wordt vastgesteld. Bij hen is de beweging van een van de armen verstoord. Dit komt doordat het deel in de hersenen dat de spieren aanstuurt, beschadigd is. Hierdoor kunnen patienten veel dagelijkse activiteiten niet of slechts met moeite uitvoeren. Het lijkt erop dat niet alleen het bewegingspatroon verandert, maar ook de structuren van het spierskelet-systeem (het samenspel tussen spieren en skelet). De combinatie van deze veranderingen maakt het moeilijk voor CP-patienten om pols en elleboog te strekken of de onderarm te draaien. De Bruin onderzocht welke veranderingen in het spierskelet-systeem bepalend zijn voor de typische bewegingsbeperkingen van de hand en arm bij CP. Kennis daarover helpt bij het vinden van (in de toekomst wellicht preventieve) behandelingen voor patienten met CP.
8 citations
TL;DR: The potential for biological compliance to not only alter the demands on muscle but also fundamentally change contractile performance is addressed.
Abstract: McNeill Alexander demonstrated that compliant tendons could improve locomotor performance by decoupling muscle length changes from joint movements and mechanical energy fluctuations. This was revolutionary for our understanding of animal locomotion, but also highlighted the limitations of our understanding of the contractile performance of muscle under the dynamic conditions relevant to movement. This review addresses the potential for biological compliance to not only alter the demands on muscle but also fundamentally change contractile performance. Compliance exists across all spatial scales within the muscle. Molecule scale compliance is observed in the thin filament and the cytoskeletal protein titin likely acts as an activation-dependent variable-stiffness spring. Larger scale connective tissue compliance is found not only in tendons but also the more structurally complex extracellular matrix and aponeuroses. The interaction of the compliance in these structures with the contractile elements of muscle, and the variation in this interaction across physiological conditions, appears to explain muscle phenomena central to locomotion but not readily explained by the crossbridge and sliding filament theories, such as history dependence, the energetics of cyclical contractions, the nonlinear effect of activation level on muscle performance and the effect of age on muscle and locomotor capacity.
8 citations
TL;DR: It can be concluded that the equine multifidus muscle in horses is an immunohistochemically homogeneous muscle with various architectural designs that have functional significance according to the vertebral motion segments considered.
Abstract: The multifidus muscle fascicles of horses attach to vertebral spinous processes after crossing between one to six metameres. The fascicles within one or two metameres are difficult to distinguish in horses. A vertebral motion segment is anatomically formed by two adjacent vertebrae and the interposed soft tissue structures, and excessive mobility of a vertebral motion segment frequently causes osteoarthropathies in sport horses. The importance of the equine multifidus muscle as a vertebral motion segment stabilizer has been demonstrated; however, there is scant documentation of the structure and function of this muscle. By studying six sport horses postmortem, the normalized muscle fibre lengths of the the multifidus muscle attached to the thoracic (T)4, T9, T12, T17 and lumbar (L)3 vertebral motion segments were determined and the relative areas occupied by fibre types I, IIA and IIX were measured in the same muscles after immunohistochemical typying. The values for the normalized muscle fibre lengths and the relative areas were analysed as completely randomized blocks using an anova (P ≤ 0.05). The vertebral motion segments of the T4 vertebra include multifidus bundles extending between two and eight metameres; the vertebral motion segments of the T9, T12, T17 and L3 vertebrae contain fascicles extending between two and four metameres The muscle fibres with high normalized lengths that insert into the T4 (three and eight metameres) vertebral motion segment tend to have smaller physiological cross-sectional areas, indicating their diminished capacity to generate isometric force. In contrast, the significantly decreased normalized muscle fibre lengths and the increased physiological cross-sectional areas of the fascicles of three metameres with insertions on T9, T17, T12, L3 and the fascicles of four metameres with insertions on L3 increase their capacities to generate isometric muscle force and neutralize excessive movements of the vertebral segments with great mobility. There were no significant differences in the values of relative areas occupied by fibre types I, IIA and IIX. In considering the relative areas occupied by the fibre types in the multifidus muscle fascicles attached to each vertebral motion segment examined, the relative area occupied by the type I fibres was found to be significantly higher in the T4 vertebral motion segment than in the other segments. It can be concluded that the equine multifidus muscle in horses is an immunohistochemically homogeneous muscle with various architectural designs that have functional significance according to the vertebral motion segments considered. The results obtained in this study can serve as a basis for future research aimed at understanding the posture and dynamics of the equine spine.
7 citations
Cites background from "Elucidation of extracellular matrix..."
...…fibres of different lengths packaged within common aponeuroses indicate their adaptive, intersegmental and synergistic capacities (Higham & Biewener, 2011; Meyer & Lieber, 2011) in horses, which allow for better maintenance of intervertebral stability (van Weeren et al. 2010; Stubbs et al. 2011)....
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References
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TL;DR: Naive mesenchymal stem cells are shown here to specify lineage and commit to phenotypes with extreme sensitivity to tissue-level elasticity, consistent with the elasticity-insensitive commitment of differentiated cell types.
12,204 citations
"Elucidation of extracellular matrix..." refers background in this paper
...Since substrate biomechanical properties have been shown to be critical in the biology of tissue development and remodeling (Engler et al., 2006; Gilbert et al., 2010), it is likely that mechanics are critical for ECM to perform its function....
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TL;DR: Using a bioengineered substrate to recapitulate key biophysical and biochemical niche features in conjunction with a highly automated single-cell tracking algorithm, it is shown that substrate elasticity is a potent regulator of MuSC fate in culture.
Abstract: Stem cells that naturally reside in adult tissues, such as muscle stem cells (MuSCs), exhibit robust regenerative capacity in vivo that is rapidly lost in culture. Using a bioengineered substrate to recapitulate key biophysical and biochemical niche features in conjunction with a highly automated single-cell tracking algorithm, we show that substrate elasticity is a potent regulator of MuSC fate in culture. Unlike MuSCs on rigid plastic dishes (approximately 10(6) kilopascals), MuSCs cultured on soft hydrogel substrates that mimic the elasticity of muscle (12 kilopascals) self-renew in vitro and contribute extensively to muscle regeneration when subsequently transplanted into mice and assayed histologically and quantitatively by noninvasive bioluminescence imaging. Our studies provide novel evidence that by recapitulating physiological tissue rigidity, propagation of adult muscle stem cells is possible, enabling future cell-based therapies for muscle-wasting diseases.
1,428 citations
"Elucidation of extracellular matrix..." refers background in this paper
...Since substrate biomechanical properties have been shown to be critical in the biology of tissue development and remodeling (Engler et al., 2006; Gilbert et al., 2010), it is likely that mechanics are critical for ECM to perform its function....
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1,224 citations
"Elucidation of extracellular matrix..." refers background in this paper
...Since substrate biomechanical properties have been shown to be critical in the biology of tissue development and remodeling (Engler et al., 2006; Gilbert et al., 2010), it is likely that mechanics are critical for ECM to perform its function....
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TL;DR: Avian integrin shows little specificity and appears to behave as a multifunctional, promiscuous receptor for extracellular matrix molecules, and post-translational modifications provide yet another mechanism for regulating integrin-ligand binding.
Abstract: Table 2 lists most of the extracellular matrix and related receptors identified to date. The wide range of binding affinities of these receptors for their ligands may be important to their function. The affinity of integrins for fibronectin is moderate, with a dissociation constant in the micromolar range. This affinity level leads to relatively rapid dissociation and reformation of receptor-ligand complexes. Thus changes in component concentration can shift binding equilibria within minutes (the time scale of many biologic phenomena) and change the number or organization of adhesive complexes. This type of interaction would be useful in motile cells, in which adhesions must form and dissociate rapidly. In contrast, the affinity of the 68-kDa laminin receptor for its ligand is three orders of magnitude higher. Such levels of affinity would be useful in stabilizing tissue. Members of the integrin family appear to recognize an RGD sequence on the ligands to which they bind. Since there are many ligands containing the RGD sequence, the question of specificity arises. Avian integrin shows little specificity and appears to behave as a multifunctional, promiscuous receptor for extracellular matrix molecules. Figure 1 summarizes our current view of the structural and functional features of avian integrin. In contrast, the mammalian receptors for vitronectin and fibronectin are specific for their respective ligands. More than one of these receptors may be present simultaneously on a cell surface, e.g. fibroblasts express receptors for fibronectin, laminin, and vitronectin at the same time. This multiplicity of receptors provides potential mechanisms for generating the adhesive differences among cells believed to play a prominent role in morphogenesis. Further adhesive differences may stem from the formation of different combinations of various alpha- and beta-subunits expressed in the cell. The mechanism of regulation of adhesive interactions with the extracellular matrix is only beginning to be explored. There are several levels at which this regulation might occur. Integrin appears to be more regionalized in more developed cells that are integral parts of tissue structures. Changes in receptor distribution could alter the relative strength of adhesive interactions. In certain instances, avian integrin disappears, or its concentration is reduced, e.g. during the development of embryonic lung (Chen et al 1986) and erythroid cells (Patel & Lodish 1985). Post-translational modifications provide yet another mechanism for regulating integrin-ligand binding.(ABSTRACT TRUNCATED AT 400 WORDS)
784 citations
"Elucidation of extracellular matrix..." refers background in this paper
...Extracellular matrix (ECM) is essential for the development, maintenance and regeneration of skeletal muscle (Buck and Horwitz, 1987; Purslow, 2002)....
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...The importance of the extracellular matrix (ECM) in muscle is widely recognized, since ECM plays a central role in proper muscle development (Buck and Horwitz, 1987), tissue structural support (Purslow, 2002), and transmission ofmechanical signals between fibers and tendon (Huijing, 1999)....
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...…r a c t The importance of the extracellular matrix (ECM) in muscle is widely recognized, since ECM plays a central role in proper muscle development (Buck and Horwitz, 1987), tissue structural support (Purslow, 2002), and transmission ofmechanical signals between fibers and tendon (Huijing, 1999)....
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TL;DR: The passive tension-sarcomere length relation of rat cardiac muscle was investigated by studying passive (or not activated) single myocytes and trabeculae and the contribution of collagen, titin, microtubules, and intermediate filaments to tension and stiffness was investigated.
587 citations
"Elucidation of extracellular matrix..." refers methods in this paper
...Previous studies used methods of subtraction, where the ECM was ‘‘preferentially’’ digested from muscle and its properties inferred from subtracting the digested state from the undigested state (see review by Fomovsky et al., 2010; Granzier and Irving, 1995)....
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