scholarly journals Alterations of Extracellular Matrix Mechanical Properties Contribute to Age-Related Functional Impairment of Human Skeletal Muscles

2020 ◽  
Vol 21 (11) ◽  
pp. 3992 ◽  
Author(s):  
Piero Pavan ◽  
Elena Monti ◽  
Michela Bondí ◽  
Chenglei Fan ◽  
Carla Stecco ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Skeletal Muscles ◽  
Sarcomere Length ◽  
Muscle Fibers ◽  
Muscle Area ◽  
Age Related ◽  
Collagen Accumulation ◽  
The Difference ◽  
Picrosirius Red ◽  
Human Skeletal Muscles

Aging of human skeletal muscles is associated with increased passive stiffness, but it is still debated whether muscle fibers or extracellular matrix (ECM) are the determinants of such change. To answer this question, we compared the passive stress generated by elongation of fibers alone and arranged in small bundles in young healthy (Y: 21 years) and elderly (E: 67 years) subjects. The physiological range of sarcomere length (SL) 2.5–3.3 μm was explored. The area of ECM between muscle fibers was determined on transversal sections with picrosirius red, a staining specific for collagen fibers. The passive tension of fiber bundles was significantly higher in E compared to Y at all SL. However, the resistance to elongation of fibers alone was not different between the two groups, while the ECM contribution was significantly increased in E compared to Y. The proportion of muscle area occupied by ECM increased from 3.3% in Y to 8.2% in E. When the contribution of ECM to bundle tension was normalized to the fraction of area occupied by ECM, the difference disappeared. We conclude that, in human skeletal muscles, the age-related reduced compliance is due to an increased stiffness of ECM, mainly caused by collagen accumulation.

Effects of Aging on Type II Muscle Fibers: A Systematic Review of the Literature

2007 ◽  
Vol 15 (3) ◽  
pp. 336-348 ◽  
Author(s):  
Florian Brunner ◽  
Annina Schmid ◽  
Ali Sheikhzadeh ◽  
Margareta Nordin ◽  
Jangwhon Yoon ◽  
...  
Keyword(s):  
Systematic Review ◽  
Skeletal Muscles ◽  
Morphological Changes ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Type Ii ◽  
Review Of The Literature ◽  
Effects Of Aging ◽  
Complex Phenomena ◽  
Human Skeletal Muscles

The authors conducted a systematic review of the literature for scientific articles in selected databases to determine the effects of aging on Type II muscle fibers in human skeletal muscles. They found that aging of Type II muscle fibers is primarily associated with a loss of fibers and a decrease in fiber size. Morphological changes with increasing age particularly included Type II fiber grouping. There is conflicting evidence regarding the change of proportion of Type II fibers. Type II muscle fibers seem to play an important role in the aging process of human skeletal muscles. According to this literature review, loss of fibers, decrease in size, and fiber-type grouping represent major quantitative changes. Because the process of aging involves various complex phenomena such as fiber-type coexpression, however, it seems difficult to assign those changes solely to a specific fiber type.

scholarly journals Differences in the Charge Distribution of Glycerol-Extracted Muscle Fibers in Rigor, Relaxation, and Contraction

1974 ◽  
Vol 64 (5) ◽  
pp. 551-567 ◽  
Author(s):  
Suzanne M. Pemrick ◽  
Charles Edwards
Keyword(s):  
Charge Distribution ◽  
Sarcomere Length ◽  
Muscle Fibers ◽  
Psoas Muscle ◽  
Nonlinear Relationship ◽  
Thin Filaments ◽  
Rabbit Psoas ◽  
Relaxation Solution ◽  
The Difference ◽  
Rest Length

Glycerol-extracted rabbit psoas muscle fibers were impaled with KCl-filled glass microelectrodes. For fibers at rest-length, the potentials were significantly more negative in solutions producing relaxation than in solutions producing either rigor or contraction; further the potentials in the latter two cases were not significantly different. For stretched fibers, with no overlap between thick and thin filaments, the potentials did not differ in the rigor, the relaxation, or the contraction solutions. The potentials measured from fibers in rigor did not vary significantly with the sarcomere length. For relaxed fibers, however, the potential magnitude decreased with increasing sarcomere length. The difference between the potentials measured for rigor and relaxed fibers exhibited a nonlinear relationship with sarcomere length. The potentials from calcium-insensitive fibers were less negative in both the rigor and the relaxation solutions than those from normal fibers. When calcium-insensitive fibers had been incubated in Hasselbach and Schneider's solution plus MgCl2 or Guba-Straub's solution plus MgATP the potentials recorded upon impalement were similar in the rigor and the relaxation solution to those obtained from normal fibers in the relaxed state. It is concluded that the increase in the negative potential as the glycerinated fiber goes from rigor to relaxation may be due to an alteration in the conformation of the contractile proteins in the relaxed state.

scholarly journals A proposed role for non-junctional transverse tubules in skeletal muscle as flexible segments allowing expansion of the transverse network

2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Manuela Lavorato ◽  
Ramesh Iyer ◽  
Clara Franzini-Armstrong
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Skeletal Muscles ◽  
Sarcomere Length ◽  
Muscle Fibers ◽  
Entire Length ◽  
Small Fish ◽  
Transverse Tubules ◽  
T Tubules

Using a variety of technical approaches, we have detected the presence of continuous triads that cover the entire length of T tubules in the main white body muscles of several small fish. This is in contrast to the discontinuous association of sarcoplasmic reticulum with T tubules in the red muscles from the same fish as well as in all other previously described muscles in a large variety of skeletal muscles. We suggest that continuous triads are permissible only in muscle fibers that are not normally subject to significant changes in sarcomere length during normal in vivo activity, as is the case for white muscles in the trunk of fish.

scholarly journals Age-related divergent remodeling of the cardiac extracellular matrix in heart failure: Collagen accumulation in the young and loss in the aged

2012 ◽  
Vol 53 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Margaux A. Horn ◽  
Helen K. Graham ◽  
Mark A. Richards ◽  
Jessica D. Clarke ◽  
David J. Greensmith ◽  
...  
Keyword(s):  
Heart Failure ◽  
Extracellular Matrix ◽  
Age Related ◽  
Collagen Accumulation

Denervation does not change the ratio of collagen I and collagen III mRNA in the extracellular matrix of muscle

2007 ◽  
Vol 292 (2) ◽  
pp. R983-R987 ◽  
Author(s):  
Ellen M. Arruda ◽  
Kevin Mundy ◽  
Sarah Calve ◽  
Keith Baar
Keyword(s):  
Extracellular Matrix ◽  
Type I Collagen ◽  
Lysyl Oxidase ◽  
Muscle Fibers ◽  
Fold Increase ◽  
Collagen I ◽  
Type I ◽  
Collagen Concentration ◽  
Collagen Iii ◽  
Picrosirius Red

Denervation or inactivity is known to decrease the mass and alter the phenotype of muscle and the mechanics of tendon. It has been proposed that a shift in the collagen of the extracellular matrix (ECM) of the muscle, increasing type III and decreasing type I collagen, may be partially responsible for the observed changes. We directly investigated this hypothesis using quantitative real-time PCR on muscles and tendons that had been denervated for 5 wk. Five weeks of denervation resulted in a 2.91-fold increase in collagen concentration but no change in the content of collagen in the muscle, whereas in the tendon there was no change in either the concentration or content of collagen. The expression of collagen I, collagen III, and lysyl oxidase mRNA in the ECM of muscle decreased (76 ± 1.6%, 73 ± 2.3%, and 83 ± 3.2%, respectively) after 5 wk of denervation. Staining with picrosirius red confirmed the earlier observation of a change in staining color from red to green. Taken with the observed equivalent decreases in collagen I and III mRNA, this suggests that there was a change in orientation of the ECM of muscle becoming more aligned with the axis of the muscle fibers and no change in collagen type. The change in collagen orientation may serve to protect the smaller muscle fibers from damage by increasing the stiffness of the ECM and may partly explain why the region of the tendon closest to the muscle becomes stiffer after inactivity.

scholarly journals Intrinsic stiffness of extracellular matrix increases with age in skeletal muscles of mice

2014 ◽  
Vol 117 (4) ◽  
pp. 363-369 ◽  
Author(s):  
Lauren K. Wood ◽  
Erdan Kayupov ◽  
Jonathan P. Gumucio ◽  
Christopher L. Mendias ◽  
Dennis R. Claflin ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Tibialis Anterior ◽  
Sarcomere Length ◽  
Muscle Fibers ◽  
Passive Stiffness ◽  
Individual Muscle ◽  
Tangent Moduli ◽  
Aging Muscle ◽  
Intrinsic Stiffness ◽  
Old Mice

Advanced age is associated with increases in muscle passive stiffness, but the contributors to the changes remain unclear. Our purpose was to determine the relative contributions of muscle fibers and extracellular matrix (ECM) to muscle passive stiffness in both adult and old animals. Passive mechanical properties were determined for isolated individual muscle fibers and bundles of muscle fibers that included their associated ECM, obtained from tibialis anterior muscles of adult (8–12 mo old) and old (28–30 mo old) mice. Maximum tangent moduli of individual muscle fibers from adult and old muscles were not different at any sarcomere length tested. In contrast, the moduli of bundles of fibers from old mice was more than twofold greater than that of fiber bundles from adult muscles at sarcomere lengths >2.5 μm. Because ECM mechanical behavior is determined by the composition and arrangement of its molecular constituents, we also examined the effect of aging on ECM collagen characteristics. With aging, muscle ECM hydroxyproline content increased twofold and advanced glycation end-product protein adducts increased threefold, whereas collagen fibril orientation and total ECM area were not different between muscles from adult and old mice. Taken together, these findings indicate that the ECM of tibialis anterior muscles from old mice has a higher modulus than the ECM of adult muscles, likely driven by an accumulation of densely packed extensively crosslinked collagen.

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