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Sample records for muscle cells stimulated

  1. Electric Pulse Stimulation of Cultured Murine Muscle Cells Reproduces Gene Expression Changes of Trained Mouse Muscle

    PubMed Central

    Burch, Nathalie; Arnold, Anne-Sophie; Item, Flurin; Summermatter, Serge; Brochmann Santana Santos, Gesa; Christe, Martine; Boutellier, Urs; Toigo, Marco; Handschin, Christoph

    2010-01-01

    Adequate levels of physical activity are at the center of a healthy lifestyle. However, the molecular mechanisms that mediate the beneficial effects of exercise remain enigmatic. This gap in knowledge is caused by the lack of an amenable experimental model system. Therefore, we optimized electric pulse stimulation of muscle cells to closely recapitulate the plastic changes in gene expression observed in a trained skeletal muscle. The exact experimental conditions were established using the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) as a marker for an endurance-trained muscle fiber. We subsequently compared the changes in the relative expression of metabolic and myofibrillar genes in the muscle cell system with those observed in mouse muscle in vivo following either an acute or repeated bouts of treadmill exercise. Importantly, in electrically stimulated C2C12 mouse muscle cells, the qualitative transcriptional adaptations were almost identical to those in trained muscle, but differ from the acute effects of exercise on muscle gene expression. In addition, significant alterations in the expression of myofibrillar proteins indicate that this stimulation could be used to modulate the fiber-type of muscle cells in culture. Our data thus describe an experimental cell culture model for the study of at least some of the transcriptional aspects of skeletal muscle adaptation to physical activity. This system will be useful for the study of the molecular mechanisms that regulate exercise adaptation in muscle. PMID:20532042

  2. Stimulation of aortic smooth muscle cell mitogenesis by serotonin

    SciTech Connect

    Nemecek, G.M.; Coughlin, S.R.; Handley, D.A.; Moskowitz, M.A.

    1986-02-01

    Bovine aortic smooth muscle cells in vitro responded to 1 nM to 10 ..mu..M serotonin with increased incorporation of (/sup 3/H)thymidine into DNA. The mitogenic effect of serotonin was half-maximal at 80 nM and maximal above 1 ..mu..M. At a concentration of 1 ..mu..M, serotonin stimulated smooth muscle cell mitogenesis to the same extent as human platelet-derived growth factor (PDGF) at 12 ng/ml. Tryptamine was approx. = 1/10th as potent as serotonin as a mitogen for smooth muscle cells. Other indoles that are structurally related to serotonin (D- and L-tryptophan, 5-hydroxy-L-tryptophan, N-acetyl-5-hydroxytryptamine, melatonin, 5-hydroxyindoleacetic acid, and 5-hydroxytryptophol) and quipazine were inactive. The stimulatory effect of serotonin on smooth muscle cell DNA synthesis required prolonged (20-24 hr) exposure to the agonist and was attenuated in the presence of serotonin D receptor antagonists. When smooth muscle cells were incubated with submaximal concentrations of serotonin and PDGF, synergistic rather than additive mitogenic responses were observed. These data indicate that serotonin has a significant mitogenic effect on smooth muscle cells in vitro, which appears to be mediated by specific plasma membrane receptors.

  3. Electrical stimulation by enzymatic biofuel cell to promote proliferation, migration and differentiation of muscle precursor cells.

    PubMed

    Lee, Jae Ho; Jeon, Won-Yong; Kim, Hyug-Han; Lee, Eun-Jung; Kim, Hae-Won

    2015-01-01

    Electrical stimulation is a very important biophysical cue for skeletal muscle maintenance and myotube formation. The absence of electrical signals from motor neurons causes denervated muscles to atrophy. Herein, we investigate for the first time the utility of an enzymatic biofuel cell (EBFC) as a promising means for mimicking native electrical stimulation. EBFC was set up using two different enzymes: one was glucose oxidase (GOX) used for the generation of anodic current followed by the oxidation of glucose; the other was Bilirubin oxidase (BOD) for the generation of cathodic current followed by the reduction of oxygen. We studied the behaviors of muscle precursor cells (MPCs) in terms of proliferation, migration and differentiation under different electrical conditions. The EBFC electrical stimulations significantly increased cell proliferation and migration. Furthermore, the electrical stimulations promoted the differentiation of cells into myotube formation based on expressions at the gene and protein levels. The EBFC set up, with its free forms adjustable to any implant design, was subsequently applied to the nanofiber scaffolding system. The MPCs were demonstrated to be stimulated in a similar manner as the 2D culture conditions, suggesting potential applications of the EBFC system for muscle repair and regeneration.

  4. Analysis of electric field stimulation of single cardiac muscle cells.

    PubMed Central

    Tung, L; Borderies, J R

    1992-01-01

    Electrical stimulation of cardiac cells by imposed extracellular electric fields results in a transmembrane potential which is highly nonuniform, with one end of the cell depolarized and the other end hyperpolarized along the field direction. To date, the implications of the close proximity of oppositely polarized membranes on excitability have not been explored. In this work we compare the biophysical basis for field stimulation of cells at rest with that for intracellular current injection, using three Luo-Rudy type membrane patches coupled together as a lumped model to represent the cell membrane. Our model shows that cell excitation is a function of the temporal and spatial distribution of ionic currents and transmembrane potential. The extracellular and intracellular forms of stimulation were compared in greater detail for monophasic and symmetric biphasic rectangular pulses, with duration ranging from 0.5 to 10 ms. Strength-duration curves derived for field stimulation show that over a wide range of pulse durations, biphasic waveforms can recruit and activate membrane patches about as effectively as can monophasic waveforms having the same total pulse duration. We find that excitation with biphasic stimulation results from a synergistic, temporal summation of inward currents through the sodium channel in membrane patches at opposite ends of the cell. Furthermore, with both waveform types, a net inward current through the inwardly rectifying potassium channel contributes to initial membrane depolarization. In contrast, models of stimulation by intracellular current injection do not account for the nonuniformity of transmembrane potential and produce substantially different (even contradictory) results for the case of stimulation from rest. PMID:1420884

  5. Electrical stimulation as a biomimicry tool for regulating muscle cell behavior

    PubMed Central

    Ahadian, Samad; Ostrovidov, Serge; Hosseini, Vahid; Kaji, Hirokazu; Ramalingam, Murugan; Bae, Hojae; Khademhosseini, Ali

    2013-01-01

    There is a growing need to understand muscle cell behaviors and to engineer muscle tissues to replace defective tissues in the body. Despite a long history of the clinical use of electric fields for muscle tissues in vivo, electrical stimulation (ES) has recently gained significant attention as a powerful tool for regulating muscle cell behaviors in vitro. ES aims to mimic the electrical environment of electroactive muscle cells (e.g., cardiac or skeletal muscle cells) by helping to regulate cell-cell and cell-extracellular matrix (ECM) interactions. As a result, it can be used to enhance the alignment and differentiation of skeletal or cardiac muscle cells and to aid in engineering of functional muscle tissues. Additionally, ES can be used to control and monitor force generation and electrophysiological activity of muscle tissues for bio-actuation and drug-screening applications in a simple, high-throughput, and reproducible manner. In this review paper, we briefly describe the importance of ES in regulating muscle cell behaviors in vitro, as well as the major challenges and prospective potential associated with ES in the context of muscle tissue engineering. PMID:23823664

  6. Electrical stimulation as a biomimicry tool for regulating muscle cell behavior.

    PubMed

    Ahadian, Samad; Ostrovidov, Serge; Hosseini, Vahid; Kaji, Hirokazu; Ramalingam, Murugan; Bae, Hojae; Khademhosseini, Ali

    2013-01-01

    There is a growing need to understand muscle cell behaviors and to engineer muscle tissues to replace defective tissues in the body. Despite a long history of the clinical use of electric fields for muscle tissues in vivo, electrical stimulation (ES) has recently gained significant attention as a powerful tool for regulating muscle cell behaviors in vitro. ES aims to mimic the electrical environment of electroactive muscle cells (e.g., cardiac or skeletal muscle cells) by helping to regulate cell-cell and cell-extracellular matrix (ECM) interactions. As a result, it can be used to enhance the alignment and differentiation of skeletal or cardiac muscle cells and to aid in engineering of functional muscle tissues. Additionally, ES can be used to control and monitor force generation and electrophysiological activity of muscle tissues for bio-actuation and drug-screening applications in a simple, high-throughput, and reproducible manner. In this review paper, we briefly describe the importance of ES in regulating muscle cell behaviors in vitro, as well as the major challenges and prospective potential associated with ES in the context of muscle tissue engineering.

  7. Electrical stimulation influences satellite cell proliferation and apoptosis in unloading-induced muscle atrophy in mice.

    PubMed

    Guo, Bao-Sheng; Cheung, Kwok-Kuen; Yeung, Simon S; Zhang, Bao-Ting; Yeung, Ella W

    2012-01-01

    Muscle atrophy caused by disuse is accompanied by adverse physiological and functional consequences. Satellite cells are the primary source of skeletal muscle regeneration. Satellite cell dysfunction, as a result of impaired proliferative potential and/or increased apoptosis, is thought to be one of the causes contributing to the decreased muscle regeneration capacity in atrophy. We have previously shown that electrical stimulation improved satellite cell dysfunction. Here we test whether electrical stimulation can also enhance satellite cell proliferative potential as well as suppress apoptotic cell death in disuse-induced muscle atrophy. Eight-week-old male BALB/c mice were subjected to a 14-day hindlimb unloading procedure. During that period, one limb (HU-ES) received electrical stimulation (frequency: 20 Hz; duration: 3 h, twice daily) while the contralateral limb served as control (HU). Immunohistochemistry and western blotting techniques were used to characterize specific proteins in cell proliferation and apoptosis. The HU-ES soleus muscles showed significant improvement in muscle mass, cross-sectional area, and peak tetanic force relative to the HU limb (p<0.05). The satellite cell proliferative activity as detected within the BrdU+/Pax7+ population was significantly higher (p<0.05). The apoptotic myonuclei (detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) and the apoptotic satellite cells (detected by cleaved Poly [ADP-ribose] polymerase co-labeled with Pax7) were reduced (p<0.05) in the HU-ES limb. Furthermore the apoptosis-inducing factor and cleaved caspase-3 were down-regulated while the anti-apoptotic Bcl-2 protein was up-regulated (p<0.05), in the HU-ES limb. These findings suggest that the electrical stimulation paradigm provides an effective stimulus to rescue the loss of myonuclei and satellite cells in disuse muscle atrophy, thus maintaining a viable satellite cell pool for subsequent muscle regeneration

  8. Serum stimulation, cell-cell interactions, and extracellular matrix independently influence smooth muscle cell phenotype in vitro.

    PubMed Central

    Kato, S.; Shanley, J. R.; Fox, J. C.

    1996-01-01

    Vascular injury profoundly alters the vessel wall microenvironment, and smooth muscle cells respond with cell cycle re-entry, loss of contractile elements, extracellular matrix remodeling, and altered signaling by endogenous growth factors and their receptors. Environmental cues include stimulation by exogenous mitogens and both cell-cell and cell-matrix interactions. Modeling this process in smooth muscle cells in vitro, these environmental determinants were varied independently and the phenotypic consequences assessed. Mitogenic stimulation with serum promoted the synthesis of collagen and fibronectin and the expression of fibroblast growth factor receptor-1 and suppressed the content of smooth muscle alpha-actin, myosin heavy chain, and basic fibroblast growth factor. Low cell density (reduced cell-cell contact) was also associated with enhanced extracellular matrix protein production, increased fibroblast growth factor receptor-1 expression, and reduced contractile protein and basic fibroblast growth factor content. The influence of serum stimulation and reduced cell-cell contact were independent and additive. Provision of a type I collagen matrix blunted the influence of serum and cell-cell contact on collagen synthesis but had minor effects on other measures of phenotype. Environmental factors thus independently influence smooth muscle cell phenotype, including endogenous growth factor expression and responsiveness, which can in turn influence the microenvironment of the vessel wall after injury. Images Figure 1 Figure 5 Figure 6 PMID:8702006

  9. Neuromuscular electrical stimulation as a method to maximize the beneficial effects of muscle stem cells transplanted into dystrophic skeletal muscle.

    PubMed

    Distefano, Giovanna; Ferrari, Ricardo Jose; Weiss, Christopher; Deasy, Bridget M; Boninger, Michael L; Fitzgerald, G Kelley; Huard, Johnny; Ambrosio, Fabrisia

    2013-01-01

    Cellular therapy is a potential approach to improve the regenerative capacity of damaged or diseased skeletal muscle. However, its clinical use has often been limited by impaired donor cell survival, proliferation and differentiation following transplantation. Additionally, functional improvements after transplantation are all-too-often negligible. Because the host microenvironment plays an important role in the fate of transplanted cells, methods to modulate the microenvironment and guide donor cell behavior are warranted. The purpose of this study was to investigate whether the use of neuromuscular electrical stimulation (NMES) for 1 or 4 weeks following muscle-derived stem cell (MDSC) transplantation into dystrophic skeletal muscle can modulate the fate of donor cells and enhance their contribution to muscle regeneration and functional improvements. Animals submitted to 4 weeks of NMES after transplantation demonstrated a 2-fold increase in the number of dystrophin+ myofibers as compared to control transplanted muscles. These findings were concomitant with an increased vascularity in the MDSC+NMES group when compared to non-stimulated counterparts. Additionally, animals subjected to NMES (with or without MDSC transplantation) presented an increased maximal specific tetanic force when compared to controls. Although cell transplantation and/or the use of NMES resulted in no changes in fatigue resistance, the combination of both MDSC transplantation and NMES resulted in a faster recovery from fatigue, when compared to non-injected and non-stimulated counterparts. We conclude that NMES is a viable method to improve MDSC engraftment, enhance dystrophic muscle strength, and, in combination with MDSC transplantation, improve recovery from fatigue. These findings suggest that NMES may be a clinically-relevant adjunct approach for cell transplantation into skeletal muscle.

  10. p-Synephrine stimulates glucose consumption via AMPK in L6 skeletal muscle cells.

    PubMed

    Hong, Na-Young; Cui, Zhi-Gang; Kang, Hee-Kyoung; Lee, Dae-Ho; Lee, Young-Ki; Park, Deok-Bae

    2012-02-24

    Interest in p-synephrine, the primary protoalkaloid in the extract of bitter orange and other citrus species, has increased due to its various pharmacological effects and related adverse effects. The lipolytic activity of p-synephrine has been repeatedly revealed by in vitro and in vivo studies and p-synephrine is currently marketed as a dietary supplement for weight loss. The present study investigated the effect of p-synephrine on glucose consumption and its action mechanism in L6 skeletal muscle cells. Treatment of L6 skeletal muscle cells with p-synephrine (0-100μM) did not affect cell viability and increased basal glucose consumption up to 50% over the control in a dose-dependent manner. The basal- or insulin-stimulated lactic acid production as well as glucose consumption was significantly increased by the addition of p-synephrine. p-Synephrine stimulated the phosphorylation of AMPK but not of Akt. p-Synephrine-induced glucose consumption was sensitive to the inhibition of AMPK but not to the inhibition of PI3 kinase. p-Synephrine also stimulated the translocation of Glut4 from the cytoplasm to the plasma membrane; this stimulation was suppressed by the inhibition of AMPK, but not of PI3 kinase. Taken together, p-synephrine can stimulate glucose consumption (Glut4-dependent glucose uptake) by stimulating AMPK activity, regardless of insulin-stimulated PI3 kinase-Akt activity in L6 skeletal muscle cells.

  11. Magnesium used in bioabsorbable stents controls smooth muscle cell proliferation and stimulates endothelial cells in vitro.

    PubMed

    Sternberg, Katrin; Gratz, Matthias; Koeck, Kathleen; Mostertz, Joerg; Begunk, Robert; Loebler, Marian; Semmling, Beatrice; Seidlitz, Anne; Hildebrandt, Petra; Homuth, Georg; Grabow, Niels; Tuemmler, Conny; Weitschies, Werner; Schmitz, Klaus-Peter; Kroemer, Heyo K

    2012-01-01

    Magnesium-based bioabsorbable cardiovascular stents have been developed to overcome limitations of permanent metallic stents, such as late stent thrombosis. During stent degradation, endothelial and smooth muscle cells will be exposed to locally high magnesium concentrations with yet unknown physiological consequences. Here, we investigated the effects of elevated magnesium concentrations on human coronary artery endothelial and smooth muscle cell (HCAEC, HCASMC) growth and gene expression. In the course of 24 h after incubation with magnesium chloride solutions (1 or 10 mM) intracellular magnesium level in HCASMC raised from 0.55 ± 0.25 mM (1 mM) to 1.38 ± 0.95 mM (10 mM), while no increase was detected in HCAEC. Accordingly, a DNA microarray-based study identified 69 magnesium regulated transcripts in HCAEC, but 2172 magnesium regulated transcripts in HCASMC. Notably, a significant regulation of various growth factors and extracellular matrix components was observed. In contrast, viability and proliferation of HCAEC were increased at concentrations of up to 25 mM magnesium chloride, while in HCASMC viability and proliferation appeared to be unaffected. Taken together, our data indicate that magnesium halts smooth muscle cell proliferation and stimulates endothelial cell proliferation, which might translate into a beneficial effect in the setting of stent associated vascular injury.

  12. Cultured slow vs. fast skeletal muscle cells differ in physiology and responsiveness to stimulation.

    PubMed

    Huang, Yen-Chih; Dennis, Robert G; Baar, Keith

    2006-07-01

    In vitro studies have used protein markers to distinguish between myogenic cells isolated from fast and slow skeletal muscles. The protein markers provide some support for the hypothesis that satellite cells from fast and slow muscles are different, but the data are equivocal. To test this hypothesis directly, three-dimensional skeletal muscle constructs were engineered from myogenic cells isolated from fast tibialis anterior (TA) and slow soleus (SOL) muscles of rats and functionality was tested. Time to peak twitch tension (TPT) and half relaxation time (RT(1/2)) were approximately 30% slower in constructs from the SOL. The slower contraction and relaxation times for the SOL constructs resulted in left shift of the force-frequency curve compared with those from the TA. Western blot analysis showed a 60% greater quantity of fast myosin heavy chain in the TA constructs. 14 days of chronic low-frequency electrical stimulation resulted in a 15% slower TPT and a 14% slower RT(1/2), but no change in absolute force production in the TA constructs. In SOL constructs, slow electrical stimulation resulted in an 80% increase in absolute force production with no change in TPT or RT(1/2). The addition of cyclosporine A did not prevent the increase in force in SOL constructs after chronic low-frequency electrical stimulation, suggesting that calcineurin is not responsible for the increase in force. We conclude that myogenic cells associated with a slow muscle are imprinted to produce muscle that contracts and relaxes slowly and that calcineurin activity cannot explain the response to a slow pattern of electrical stimulation.

  13. Engineering skeletal muscle tissues from murine myoblast progenitor cells and application of electrical stimulation.

    PubMed

    van der Schaft, Daisy W J; van Spreeuwel, Ariane C C; Boonen, Kristel J M; Langelaan, Marloes L P; Bouten, Carlijn V C; Baaijens, Frank P T

    2013-03-19

    Engineered muscle tissues can be used for several different purposes, which include the production of tissues for use as a disease model in vitro, e.g. to study pressure ulcers, for regenerative medicine and as a meat alternative (1). The first reported 3D muscle constructs have been made many years ago and pioneers in the field are Vandenburgh and colleagues (2,3). Advances made in muscle tissue engineering are not only the result from the vast gain in knowledge of biochemical factors, stem cells and progenitor cells, but are in particular based on insights gained by researchers that physical factors play essential roles in the control of cell behavior and tissue development. State-of-the-art engineered muscle constructs currently consist of cell-populated hydrogel constructs. In our lab these generally consist of murine myoblast progenitor cells, isolated from murine hind limb muscles or a murine myoblast cell line C2C12, mixed with a mixture of collagen/Matrigel and plated between two anchoring points, mimicking the muscle ligaments. Other cells may be considered as well, e.g. alternative cell lines such as L6 rat myoblasts (4), neonatal muscle derived progenitor cells (5), cells derived from adult muscle tissues from other species such as human (6) or even induced pluripotent stem cells (iPS cells) (7). Cell contractility causes alignment of the cells along the long axis of the construct (8,9) and differentiation of the muscle progenitor cells after approximately one week of culture. Moreover, the application of electrical stimulation can enhance the process of differentiation to some extent (8). Because of its limited size (8 x 2 x 0.5 mm) the complete tissue can be analyzed using confocal microscopy to monitor e.g. viability, differentiation and cell alignment. Depending on the specific application the requirements for the engineered muscle tissue will vary; e.g. use for regenerative medicine requires the up scaling of tissue size and vascularization, while

  14. Engineering Skeletal Muscle Tissues from Murine Myoblast Progenitor Cells and Application of Electrical Stimulation

    PubMed Central

    van der Schaft, Daisy W. J.; van Spreeuwel, Ariane C. C.; Boonen, Kristel J. M.; Langelaan, Marloes L. P.; Bouten, Carlijn V. C.; Baaijens, Frank P. T.

    2013-01-01

    Engineered muscle tissues can be used for several different purposes, which include the production of tissues for use as a disease model in vitro, e.g. to study pressure ulcers, for regenerative medicine and as a meat alternative 1. The first reported 3D muscle constructs have been made many years ago and pioneers in the field are Vandenburgh and colleagues 2,3. Advances made in muscle tissue engineering are not only the result from the vast gain in knowledge of biochemical factors, stem cells and progenitor cells, but are in particular based on insights gained by researchers that physical factors play essential roles in the control of cell behavior and tissue development. State-of-the-art engineered muscle constructs currently consist of cell-populated hydrogel constructs. In our lab these generally consist of murine myoblast progenitor cells, isolated from murine hind limb muscles or a murine myoblast cell line C2C12, mixed with a mixture of collagen/Matrigel and plated between two anchoring points, mimicking the muscle ligaments. Other cells may be considered as well, e.g. alternative cell lines such as L6 rat myoblasts 4, neonatal muscle derived progenitor cells 5, cells derived from adult muscle tissues from other species such as human 6 or even induced pluripotent stem cells (iPS cells) 7. Cell contractility causes alignment of the cells along the long axis of the construct 8,9 and differentiation of the muscle progenitor cells after approximately one week of culture. Moreover, the application of electrical stimulation can enhance the process of differentiation to some extent 8. Because of its limited size (8 x 2 x 0.5 mm) the complete tissue can be analyzed using confocal microscopy to monitor e.g. viability, differentiation and cell alignment. Depending on the specific application the requirements for the engineered muscle tissue will vary; e.g. use for regenerative medicine requires the up scaling of tissue size and vascularization, while to serve as a

  15. Insulin-like growth factor I stimulates elastin synthesis by bovine pulmonary arterial smooth muscle cells.

    PubMed

    Badesch, D B; Lee, P D; Parks, W C; Stenmark, K R

    1989-04-14

    Insulin-like growth factor I stimulates mitogenesis in smooth muscle cells, and upregulates elastin synthesis in embryonic aortic tissue. Increased smooth muscle elastin synthesis may play an important role in vascular remodeling in chronic pulmonary hypertension. Therefore, we studied the effect of IGF-I on elastin and total protein synthesis by pulmonary arterial smooth muscle cells in vitro. Tropoelastin synthesis was measured by enzyme immunoassay, and total protein synthesis was measured by [3H]-leucine incorporation. In addition, the steady-state levels of tropoelastin mRNA were determined by slot blot hybridization. Incubation of confluent cultures with various concentrations of IGF-I resulted in a dose-dependent stimulation of elastin synthesis, with a 2.4-fold increase over control levels at 1000 ng/ml of IGF. The increase in elastin synthesis was reflected by a stimulation of the steady-state levels of tropoelastin mRNA. We conclude that IGF-I has potent elastogenic effects on vascular smooth muscle cells, and speculate that it may contribute to vascular wall remodeling in chronic hypertension.

  16. Electrically Stimulated Adipose Stem Cells on Polypyrrole-Coated Scaffolds for Smooth Muscle Tissue Engineering.

    PubMed

    Björninen, Miina; Gilmore, Kerry; Pelto, Jani; Seppänen-Kaijansinkko, Riitta; Kellomäki, Minna; Miettinen, Susanna; Wallace, Gordon; Grijpma, Dirk; Haimi, Suvi

    2017-04-01

    We investigated the use of polypyrrole (PPy)-coated polymer scaffolds and electrical stimulation (ES) to differentiate adipose stem cells (ASCs) towards smooth muscle cells (SMCs). Since tissue engineering lacks robust and reusable 3D ES devices we developed a device that can deliver ES in a reliable, repeatable, and cost-efficient way in a 3D environment. Long pulse (1 ms) or short pulse (0.25 ms) biphasic electric current at a frequency of 10 Hz was applied to ASCs to study the effects of ES on ASC viability and differentiation towards SMCs on the PPy-coated scaffolds. PPy-coated scaffolds promoted proliferation and induced stronger calponin, myosin heavy chain (MHC) and smooth muscle actin (SMA) expression in ASCs compared to uncoated scaffolds. ES with 1 ms pulse width increased the number of viable cells by day 7 compared to controls and remained at similar levels to controls by day 14, whereas shorter pulses significantly decreased viability compared to the other groups. Both ES protocols supported smooth muscle expression markers. Our results indicate that electrical stimulation on PPy-coated scaffolds applied through the novel 3D ES device is a valid approach for vascular smooth muscle tissue engineering.

  17. Electrical Stimulation Decreases Coupling Efficiency Between Beta-Adrenergic Receptors and Cyclic AMP Production in Cultured Muscle Cells

    NASA Technical Reports Server (NTRS)

    Young, R. B.; Bridge, K. Y.

    1999-01-01

    Electrical stimulation of skeletal muscle cells in culture is an effective way to simulate the effects of muscle contraction and its effects on gene expression in muscle cells. Expression of the beta-adrenergic receptor and its coupling to cyclic AMP synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this project was to determine if electrical stimulation altered the beta-adrenergic response in muscle cells. Chicken skeletal muscle cells that had been grown for seven days in culture were subjected to electrical stimulation for an additional two days at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. At the end of this two-day stimulation period, beta-adrenergic receptor population was measured by the binding of tritium-labeled CGP-12177 to muscle cells, and coupling to cAMP synthesis was measured by Radioimmunoassay (RIA) after treating the cells for 10 min with the potent (beta)AR agonist, isoproterenol. The number of beta adrenergic receptors and the basal levels of intracellular cyclic AMP were not affected by electrical stimulation. However, the ability of these cells to synthesize cyclic AMP was reduced by approximately 50%. Thus, an enhanced level of contraction reduces the coupling efficiency of beta-adrenergic receptors for cyclic AMP production.

  18. Effects of acetylcholine and electrical stimulation on glial cell line-derived neurotrophic factor production in skeletal muscle cells.

    PubMed

    Vianney, John-Mary; Miller, Damon A; Spitsbergen, John M

    2014-11-07

    Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophic factor required for survival of neurons in the central and peripheral nervous system. Specifically, GDNF has been characterized as a survival factor for spinal motor neurons. GDNF is synthesized and secreted by neuronal target tissues, including skeletal muscle in the peripheral nervous system; however, the mechanisms by which GDNF is synthesized and released by skeletal muscle are not fully understood. Previous results suggested that cholinergic neurons regulate secretion of GDNF by skeletal muscle. In the current study, GDNF production by skeletal muscle myotubes following treatment with acetylcholine was examined. Acetylcholine receptors on myotubes were identified with labeled alpha-bungarotoxin and were blocked using unlabeled alpha-bungarotoxin. The question of whether electrical stimulation has a similar effect to that of acetylcholine was also investigated. Cells were stimulated with voltage pulses; at 1 and 5 Hz frequencies for times ranging from 30 min to 48 h. GDNF content in myotubes and GDNF in conditioned culture medium were quantified by enzyme-linked immunosorbant assay. Results suggest that acetylcholine and short-term electrical stimulation reduce GDNF secretion, while treatment with carbachol or long-term electrical stimulation enhances GDNF production by skeletal muscle.

  19. Vasopressin-stimulated Ca2+ spiking in vascular smooth muscle cells involves phospholipase D.

    PubMed

    Li, Y; Shiels, A J; Maszak, G; Byron, K L

    2001-06-01

    Physiological concentrations of [Arg(8)]vasopressin (AVP; 10-500 pM) stimulate oscillations of cytosolic free Ca2+ concentration (Ca2+ spikes) in A7r5 vascular smooth muscle cells. We previously reported that this effect of AVP was blocked by a putative phospholipase A2 (PLA2) inhibitor, ONO-RS-082 (5 microM). In the present study, the products of PLA2, arachidonic acid (AA), and lysophospholipids were found to be ineffective in stimulating Ca2+ spiking, and inhibitors of AA metabolism did not prevent AVP-stimulated Ca2+ spiking. Thin layer chromatography was used to monitor the release of AA and phosphatidic acid (PA), which are the products of PLA2 and phospholipase D (PLD), respectively. AVP (100 pM) stimulated both AA and PA formation, but only PA formation was inhibited by ONO-RS-082 (5 microM). Exogenous PLD (type VII; 2.5 U/ml) stimulated Ca2+ spiking equivalent to the effect of 100 pM AVP. AVP stimulated transphosphatidylation of 1-butanol (a PLD-catalyzed reaction) but not 2-butanol, and 1-butanol (but not 2-butanol) completely prevented AVP-stimulated Ca2+ spiking. Protein kinase C (PKC) inhibition, which completely prevents AVP-stimulated Ca2+ spiking, did not inhibit AVP-stimulated phosphatidylbutanol formation. These results suggest that AVP-stimulated Ca2+ spiking depends on activation of PLD rather than PLA2 and that PKC activation may be downstream of PLD in the signaling cascade.

  20. Muscle Stimulation Technology

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Under a Goddard Space Flight Center contract, Electrologic of America was able to refine the process of densely packing circuitry on personal computer boards, providing significant contributions to the closed-loop systems for the Remote Manipulator System Simulator. The microcircuitry work was then applied to the StimMaster FES Ergometer, an exercise device used to stimulate muscles suffering from paralysis. The electrical stimulation equipment was developed exclusively for V-Care Health Systems, Inc. Product still commercially available as of March 2002.

  1. Transforming growth factor type beta specifically stimulates synthesis of proteoglycan in human adult arterial smooth muscle cells.

    PubMed Central

    Chen, J K; Hoshi, H; McKeehan, W L

    1987-01-01

    Myo-intimal proteoglycan metabolism is thought to be important in blood vessel homeostasis, blood clotting, atherogenesis, and atherosclerosis. Human platelet-derived transforming growth factor type beta (TGF-beta) specifically stimulated synthesis of at least two types of chondroitin sulfate proteoglycans in nonproliferating human adult arterial smooth muscle cells in culture. Stimulation of smooth muscle cell proteoglycan synthesis by smooth muscle cell growth promoters (epidermal growth factor, platelet-derived growth factor, and heparin-binding growth factors) was less than 20% of that elicited by TGF-beta. TGF-beta neither significantly stimulated proliferation of quiescent smooth muscle cells nor inhibited proliferating cells. The extent of TGF-beta stimulation of smooth muscle cell proteoglycan synthesis was similar in both nonproliferating and growth-stimulated cells. TGF-beta, which is a reversible inhibitor of endothelial cell proliferation, had no comparable effect on endothelial cell proteoglycan synthesis. These results are consistent with the hypothesis that TGF-beta is a cell-type-specific regulator of proteoglycan synthesis in human blood vessels and may contribute to the myo-intimal accumulation of proteoglycan in atherosclerotic lesions. Images PMID:3474655

  2. Resveratrol Induces Vascular Smooth Muscle Cell Differentiation through Stimulation of SirT1 and AMPK

    PubMed Central

    Thompson, Anne Marie; Martin, Kathleen A.; Rzucidlo, Eva M.

    2014-01-01

    Phenotypic plasticity in vascular smooth muscle cells (VSMC) is necessary for vessel maintenance, repair and adaptation to vascular changes associated with aging. De-differentiated VSMC contribute to pathologies including atherosclerosis and intimal hyperplasia. As resveratrol has been reported to have cardio- protective effects, we investigated its role in VSMC phenotypic modulation. We demonstrated the novel finding that resveratrol promoted VSMC differentiation as measured by contractile protein expression, contractile morphology and contraction in collagen gels. Resveratrol induced VSMC differentiation through stimulation of SirT1 and AMPK. We made the novel finding that low or high dose resveratrol had an initially different mechanism on induction of differentiation. We found that low dose resveratrol stimulated differentiation through SirT1-mediated activation of AKT, whereas high dose resveratrol stimulated differentiation through AMPK-mediated inhibition of the mTORC1 pathway, allowing activation of AKT. The health effects of resveratrol in cardiovascular diseases, cancer and longevity are an area of active research. We have demonstrated a supplemental avenue where-by resveratrol may promote health by maintaining and enhancing plasticity of the vasculature. PMID:24416418

  3. S-adenosylmethionine stimulates fatty acid metabolism-linked gene expression in porcine muscle satellite cells.

    PubMed

    Yue, Tao; Fang, Qian; Yin, JingDong; Li, DeFa; Li, Wei

    2010-10-01

    Evidence indicates that both S-adenosylmethionine (SAMe) metabolism and intramuscular fat are associated with insulin resistance and type II diabetes. However, it is still unknown whether SAMe have effects on intramuscular adipogenesis. The present study investigated the roles of SAMe in the adipogenic differentiation of porcine muscle satellite cells. Cells isolated from neonatal pig muscle were treated with different concentrations of SAMe (0, 0.5 and 1.0 mM) for 24 h, induced for a 9-day adipogenic differentiation and were finally stained by oil red O staining. The adipocyte determination and differentiation factor-1 (ADD1) and peroxisome proliferator-activated receptor gamma (PPARγ) mRNA and protein were stimulated by SAMe treatment in a dose-dependent manner. Lipoprotein lipase (LPL) mRNA and protein were enhanced in 1.0 mM treatment group, compared with the control. No significant difference was observed in the intracellular lipid content among treatments. These results provide evidence that SAMe may be associated with intramuscular adipogenesis and indicate a novel action of SAMe in fat metabolism.

  4. High pulsatility flow stimulates smooth muscle cell hypertrophy and contractile protein expression

    PubMed Central

    Scott, Devon; Tan, Yan; Shandas, Robin; Stenmark, Kurt R.

    2013-01-01

    Proximal arterial stiffening is an important predictor of events in systemic and pulmonary hypertension, partly through its contribution to downstream vascular abnormalities. However, much remains undetermined regarding the mechanisms involved in the vascular changes induced by arterial stiffening. We therefore addressed the hypothesis that high pulsatility flow, caused by proximal arterial stiffening, induces downstream pulmonary artery endothelial cell (EC) dysfunction that in turn leads to phenotypic change of smooth muscle cells (SMCs). To test the hypothesis, we employed a model pulmonary circulation in which upstream compliance regulates the pulsatility of flow waves imposed onto a downstream vascular mimetic coculture composed of pulmonary ECs and SMCs. The effects of high pulsatility flow on SMCs were determined both in the presence and absence of ECs. In the presence of ECs, high pulsatility flow increased SMC size and expression of the contractile proteins, smooth muscle α-actin (SMA) and smooth muscle myosin heavy chain (SM-MHC), without affecting proliferation. In the absence of ECs, high pulsatility flow decreased SMC expression of SMA and SM-MHC, without affecting SMC size or proliferation. To identify the molecular signals involved in the EC-mediated SMC responses, mRNA and/or protein expression of vasoconstrictors [angiotensin-converting enzyme (ACE) and endothelin (ET)-1], vasodilator (eNOS), and growth factor (TGF-β1) in EC were examined. Results showed high pulsatility flow decreased eNOS and increased ACE, ET-1, and TGF-β1 expression. ACE inhibition with ramiprilat, ET-1 receptor inhibition with bosentan, and treatment with the vasodilator bradykinin prevented flow-induced, EC-dependent SMC changes. In conclusion, high pulsatility flow stimulated SMC hypertrophy and contractile protein expression by altering EC production of vasoactive mediators and cytokines, supporting the idea of a coupling between proximal vascular stiffening, flow

  5. Muscle Derived Stem Cells Stimulate Muscle Myofiber Repair and Counteract Fat Infiltration in a Diabetic Mouse Model of Critical Limb Ischemia

    PubMed Central

    Tsao, J; Kovanecz, I; Awadalla, N; Gelfand, R; Sinha-Hikim, I; White, RA; Gonzalez-Cadavid, NF

    2017-01-01

    Background Critical Limb Ischemia (CLI) affects patients with Type 2 Diabetes (T2D) and obesity, with high risk of amputation and post-surgical mortality, and no effective medical treatment. Stem cell therapy, mainly with bone marrow mesenchymal, adipose derived, endothelial, hematopoietic, and umbilical cord stem cells, is promising in CLI mouse and rat models and is in clinical trials. Their general focus is on angiogenic repair, with no reports on the alleviation of necrosis, lipofibrosis, and myofiber regeneration in the ischemic muscle, or the use of Muscle Derived Stem Cells (MDSC) alone or in combination with pharmacological adjuvants, in the context of CLI in T2D. Methods Using a T2D mouse model of CLI induced by severe unilateral femoral artery ligation, we tested: a) the repair efficacy of MDSC implanted into the ischemic muscle and the effects of concurrent intraperitoneal administration of a nitric oxide generator, molsidomine; and b) whether MDSC may partially counteract their own repair effects by stimulating the expression of myostatin, the main lipofibrotic agent in the muscle and inhibitor of muscle mass. Results MDSC: a) reduced mortality, and b) in the ischemic muscle, increased stem cell number and myofiber central nuclei, reduced fat infiltration, myofibroblast number, and myofiber apoptosis, and increased smooth muscle and endothelial cells, as well as neurotrophic factors. The content of myosin heavy chain 2 (MHC-2) myofibers was not restored and collagen was increased, in association with myostatin overexpression. Supplementation of MDSC with molsidomine failed to stimulate the beneficial effects of MDSC, except for some reduction in myostatin overexpression. Molsidomine given alone was rather ineffective, except for inhibiting apoptosis and myostatin overexpression. Conclusions MDSC improved CLI muscle repair, but molsidomine did not stimulate this process. The combination of MDSC with anti-myostatin approaches should be explored to restore

  6. TGF-β/Smad3 Stimulates Stem Cell/Developmental Gene Expression and Vascular Smooth Muscle Cell De-Differentiation

    PubMed Central

    Franco, Sarah R.; Wang, Bowen; Seedial, Stephen; Kent, K. Craig

    2014-01-01

    Atherosclerotic-associated diseases are the leading cause of death in the United States. Despite recent progress, interventional treatments for atherosclerosis can be complicated by restenosis resulting from neo-intimal hyperplasia. We have previously demonstrated that TGF-β and its downstream signaling protein Smad3∶1) are up-regulated following vascular injury, 2) together drive smooth muscle cell (SMC) proliferation and migration and 3) enhance the development of intimal hyperplasia. In order to determine a mechanism through which TGF-β/Smad3 promote these effects, Affymetrix gene expression arrays were performed on primary rat SMCs infected with Smad3 and stimulated with TGF-β or infected with GFP alone. More than 200 genes were differentially expressed (>2.0 fold change, p<0.05) in TGF-β/Smad3 stimulated SMCs. We then performed GO term enrichment analysis using the DAVID bioinformatics database and found that TGF-β/Smad3 activated the expression of multiple genes related to either development or cell differentiation, several of which have been shown to be associated with multipotent stem or progenitor cells. Quantitative real-time PCR confirmed up-regulation of several developmental genes including FGF1, NGF, and Wnt11 (by 2.5, 6 and 7 fold, respectively) as well as stem/progenitor cell associated genes CD34 and CXCR4 (by 10 and 45 fold, respectively). In addition, up-regulation of these factors at protein levels were also confirmed by Western blotting, or by immunocytochemistry (performed for CXCR4 and NGF). Finally, TGF-β/Smad3 down regulated transcription of SMC contractile genes as well as protein production of smooth muscle alpha actin, calponin, and smooth muscle myosin heavy chain. These combined results suggest that TGF-β/Smad3 stimulation drives SMCs to a phenotypically altered state of de-differentiation through the up-regulation of developmental related genes. PMID:24718260

  7. Inhibition of Rho protein stimulates iNOS expression in rat vascular smooth muscle cells.

    PubMed

    Muniyappa, R; Xu, R; Ram, J L; Sowers, J R

    2000-06-01

    Inducible nitric oxide synthase (iNOS) in vascular smooth muscle cells (VSMCs) is upregulated in arterial injury and plays a role in regulating VSMC proliferation and restenosis. Inflammatory cytokines [e.g., interleukin-1beta (IL-1beta)] released during vascular injury induce iNOS. Small GTP-binding proteins of the Ras superfamily play a major role in IL-1beta-dependent signaling pathways. In this study, we examined the role of Rho GTPases in regulating iNOS expression in VSMCs. Treatment of VSMCs with mevastatin, which inhibits isoprenylation of Rho and other small GTP-binding proteins, produced significantly higher amounts of IL-1beta-evoked NO and iNOS protein compared with control. Similarly, bacterial toxins [Toxin B from Clostridium difficile and C3 ADP-ribosyl transferase (C3) toxin from Clostridium botulinium] that specifically inactivate Rho proteins increased NOS products (NO and citrulline) and iNOS expression. Toxin B increased the activity of iNOS promoter-reporter construct in VSMCs. Both toxins enhanced IL-1beta-stimulated iNOS expression and NO production. These data demonstrate for the first time that inhibition of Rho induces iNOS and suggest a role for Rho protein in IL-1beta-stimulated NO production in VSMCs.

  8. Laminar shear stress stimulates vascular smooth muscle cell apoptosis via the Akt pathway.

    PubMed

    Fitzgerald, Tamara N; Shepherd, Benjamin R; Asada, Hidenori; Teso, Desarom; Muto, Akihito; Fancher, Tiffany; Pimiento, Jose M; Maloney, Stephen P; Dardik, Alan

    2008-08-01

    Vascular smooth muscle cells (SMC) may be directly exposed to blood flow after an endothelial-denuding injury. It is not known whether direct exposure of SMC to shear stress reduces SMC turnover and contributes to the low rate of restenosis after most vascular interventions. This study examines if laminar shear stress inhibits SMC proliferation or stimulates apoptosis. Bovine aortic SMC were exposed to arterial magnitudes of laminar shear stress (11 dynes/cm(2)) for up to 24 h and compared to control SMC (0 dynes/cm(2)). SMC density was assessed by cell counting, DNA synthesis by (3)[H]-thymidine incorporation, and apoptosis by TUNEL staining. Akt, caspase, bax, and bcl-2 phosphorylation were assessed by Western blotting; caspase activity was also measured with an in vitro assay. Analysis of variance was used to compare groups. SMC exposed to laminar shear stress had a 38% decrease in cell number (n = 4, P = 0.03), 54% reduction in (3)[H]-thymidine incorporation (n = 3, P = 0.003), and 15-fold increase in TUNEL staining (n = 4, P < 0.0001). Akt phosphorylation was reduced by 67% (n = 3, P < 0.0001), whereas bax/bcl-2 phosphorylation was increased by 1.8-fold (n = 3, P = 0.01). Caspase-3 activity was increased threefold (n = 5, P = 0.03). Pretreatment of cells with ZVAD-fmk or wortmannin resulted in 42% increased cell retention (n = 3, P < 0.01) and a fourfold increase in apoptosis (n = 3, P < 0.04), respectively. Cells transduced with constitutively-active Akt had twofold decreased apoptosis (n = 3, P < 0.002). SMC exposed to laminar shear stress have decreased proliferation and increased apoptosis, mediated by the Akt pathway. These results suggest that augmentation of SMC apoptosis may be an alternative strategy to inhibit restenosis after vascular injury.

  9. Effect of Electrical Stimulation on Beta-Adrenergic Receptor Population and Cyclic AMP Production in Chicken and Rat Skeletal Muscle Cell Cultures

    NASA Technical Reports Server (NTRS)

    Young, Ronald B.; Bridge, Kristin Y.; Strietzel, Catherine J.

    2000-01-01

    Expression of the beta-adrenergic receptor (PAR) and its coupling to Adenosine 3'5' Cyclic Monophosphate (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the PAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture, were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the PAR population was not significantly affected by electrical stimulation; however, the ability, of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the PAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

  10. Effect of electrical stimulation on beta-adrenergic receptor population and cyclic amp production in chicken and rat skeletal muscle cell cultures

    NASA Technical Reports Server (NTRS)

    Young, R. B.; Bridge, K. Y.; Strietzel, C. J.

    2000-01-01

    Expression of the beta-adrenergic receptor (betaAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the betaAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the betaAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the betaAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

  11. Thrombin potently stimulates cytokine production in human vascular smooth muscle cells but not in mononuclear phagocytes.

    PubMed

    Kranzhöfer, R; Clinton, S K; Ishii, K; Coughlin, S R; Fenton, J W; Libby, P

    1996-08-01

    Thrombosis frequently occurs during atherogenesis and in response to vascular injury. Accumulating evidence supports a role for inflammation in the same situation. The present study therefore sought links between thrombosis and inflammation by determining whether thrombin, which is present in active form at sites of thrombosis, can elicit inflammatory functions of human monocytes and vascular smooth muscle cells (SMCs), two major constituents of advanced atheroma. Human alpha-thrombin (EC50, approximately equal to 500 pmol/L) potently induced interleukin (IL)-6 release from SMCs. The tethered-ligand thrombin receptor appeared to mediate this effect. Furthermore, alpha-thrombin also rapidly increased levels of mRNA encoding IL-6 and monocyte chemotactic protein-1 (MCP-1) in SMCs. In contrast, only alpha-thrombin concentrations of > or = 100 nmol/L could stimulate release of IL-6 or tumor necrosis factor-alpha (TNF alpha) in peripheral blood monocytes or monocyte-derived macrophages. Lipid loading of macrophages did not augment thrombin responsiveness. Likewise, only alpha-thrombin concentrations of > or = 100 nmol/L increased levels of IL-6, IL-1 beta, MCP-1, or TNF alpha mRNA in monocytes. Differential responses of SMCs and monocytes to thrombin extended to early agonist-mediated increases in [Ca2+]i. SMCs and endothelial cells, but not monocytes, contained abundant mRNA encoding the thrombin receptor and displayed cell surface thrombin receptor expression detected with a novel monoclonal antibody. Thus, the level of thrombin receptors appeared to account for the differential thrombin susceptibility of SMCs and monocytes. These data suggest that SMCs may be more sensitive than monocytes/macrophages to thrombin activation in human atheroma. Cytokines produced by thrombin-activated SMCs may contribute to ongoing inflammation in atheroma complicated by thrombosis or subjected to angioplasty.

  12. Injection of duck recombinant follistatin fusion protein into duck muscle tissues stimulates satellite cell proliferation and muscle fiber hypertrophy.

    PubMed

    Liu, He-he; Wang, Ji-wen; Yu, Hai-yue; Zhang, Rong-ping; Chen, Xi; Jin, Hai-bo; Dai, Fei; Li, Liang; Xu, Feng

    2012-06-01

    Follistatin (FST) can inhibit the expression of myostatin, which is a predominant inhibitor of muscle development. The potential application of myostatin-based technology has been prompted in different ways in agriculture. We previously constructed an expression vector of duck FST and isolated the FST fusion protein. After the protein was purified and refolded, it was added to the medium of duck myoblasts cultured in vitro. The results show that the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide value of the myoblasts in the duck FST treatment group is higher than that in the control group, which indicates that the duck FST fusion protein exhibits the biological activities that can accelerate myoblast proliferation. To further investigate the roles of duck FST on muscle development, we injected the protein into the duck muscle tissues in vivo. The results show that both the duck muscle fiber cross-sectional area and the satellite cell activation frequency are influenced more in the FST treatment group than they are in the control group. In addition to these phenomena, expression of MyoD and Myf5 were increased, and the expression of myostatin was decreased. Together, these results suggest the potential for using duck FST fusion protein to inhibit myostatin activity and subsequently to enhance muscle growth in vivo. The mechanism by which FST regulates muscle development in the duck is similar to that in mammals and fishes.

  13. Early posthatch feeding stimulates satellite cell proliferation and skeletal muscle growth in turkey poults.

    PubMed

    Halevy, Orna; Nadel, Yael; Barak, Miriam; Rozenboim, Israel; Sklan, David

    2003-05-01

    The effect of early posthatch feeding on skeletal muscle growth and satellite cell myogenesis was studied in turkey poults. Poults were either fed immediately posthatch or food-deprived for the first 48 h and then refed for the rest of the experiment. Body and breast muscle weights were lower in the starved poults than in fed controls throughout the experiment (P < 0.05). Cultures of breast muscle satellite cells revealed significantly higher DNA synthesis in the fed group than in the starved group as early as d 1 (P < 0.05). These levels continued to rise, reaching approximately 500-fold those of feed-deprived poults on d 4. In the latter group, thymidine incorporation peaked only on d 6, and then declined. Thereafter, it decreased to the same levels as those in the fed group. Satellite cell number per gram muscle increased until d 4, and was higher in the fed group than in the starved group (P < 0.05). Pax7 levels in cell cultures derived from the fed group were markedly higher than in the starved group on d 2 (P < 0.05). Myogenin levels in both culture and muscle were higher in the fed than in the starved groups until d 4 (P < 0.05). Phosphorylation of the survival factor Akt and cyclin-dependent kinase inhibitor p21 levels were higher in cells derived from the fed group relative to those from the starved group 48 h posthatch (P < 0.05). Similarly, Akt phosphorylation and insulin-like growth factor I (IGF-I) levels were significantly higher in the muscles of the fed group (P < 0.05). Together, these results suggest that immediate posthatch feeding of poults is critical for satellite cell survival and myogenesis probably via IGF-I.

  14. Effect of Electrical Stimulation on Beta-Adrenergic Receptor Population and Coupling Efficiency in Chicken and Rat Skeleton Muscle Cell Cultures

    NASA Technical Reports Server (NTRS)

    Young, Ronald B.; Bridge, Kristin Y.; Strietzel, Catherine J.

    1999-01-01

    Expression of the beta-adrenergic receptor (bAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the bAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for seven days in culture were subjected to electrical stimulation for an additional two days at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the bAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. Thus, in chicken muscle cells an enhanced level of contraction reduced the coupling efficiency of bAR for cyclic AMP production by approximately 55% compared to controls. In contrast, the bAR population in rat muscle cells was increased by approximately 25% by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was also increased by almost two-fold. Thus, in rat muscle cells an enhanced level of contraction increased the coupling efficiency of bAR for cyclic AMP production by approximately 50% compared to controls. The basal levels of intracellular cyclic AMP in both rat muscle cells and chicken muscle cells were not affected by electrical stimulation.

  15. Mechanical stimulation of skeletal muscle cells mitigates glucocorticoid-induced decreases in prostaglandin production and prostaglandin synthase activity

    NASA Technical Reports Server (NTRS)

    Chromiak, J. A.; Vandenburgh, H. H.

    1994-01-01

    The glucocorticoid dexamethasone (Dex) induces a decline in protein synthesis and protein content in tissue cultured, avian skeletal muscle cells, and this atrophy is attenuated by repetitive mechanical stretch. Since the prostaglandin synthesis inhibitor indomethacin mitigated this stretch attenuation of muscle atrophy, the effects of Dex and mechanical stretch on prostaglandin production and prostaglandin H synthase (PGHS) activity were examined. In static cultures, 10(-8) M Dex reduced PGF2 alpha production 55-65% and PGE2 production 84-90% after 24-72 h of incubation. Repetitive 10% stretch-relaxations of non-Dex-treated cultures increased PGF2 alpha efflux 41% at 24 h and 276% at 72 h, and increased PGE2 production 51% at 24 h and 236% at 72 h. Mechanical stimulation of Dex-treated cultures increased PGF2 alpha production 162% after 24 h, returning PGF2 alpha efflux to the level of non-Dex-treated cultures. At 72 h, stretch increased PGF2 alpha efflux 65% in Dex-treated cultures. Mechanical stimulation of Dex-treated cultures also increased PGE2 production at 24 h, but not at 72 h. Dex reduced PGHS activity in the muscle cultures by 70% after 8-24 h of incubation, and mechanical stimulation of the Dex-treated cultures increased PGHS activity by 98% after 24 h. Repetitive mechanical stimulation attenuates the catabolic effects of Dex on cultured skeletal muscle cells in part by mitigating the Dex-induced declines in PGHS activity and prostaglandin production.

  16. Nonlinear relationship between alpha 1-adrenergic receptor occupancy and norepinephrine-stimulated calcium flux in cultured vascular smooth muscle cells

    SciTech Connect

    Colucci, W.S.; Brock, T.A.; Gimbrone, M.A. Jr.; Alexander, R.W.

    1985-05-01

    To determine the relationship between vascular alpha 1-adrenergic receptor occupancy and receptor-coupled calcium flux, the authors have studied (/sup 3/H)prazosin binding and l-norepinephrine-induced /sup 45/Ca efflux in cultured vascular smooth muscle cells isolated from the rabbit aorta. In a crude cellular homogenate, (/sup 3/H)prazosin bound to a single high affinity site, whereas l-norepinephrine (NE) binding was best described by a two-site model. NE-stimulated /sup 45/Ca efflux was concentration-dependent (EC/sup 50/ = 108 nM) and potently inhibited by prazosin (IC/sup 50/ = 0.15 nM). For the total receptor pool identified by (/sup 3/H)prazosin binding, the relationship between receptor occupancy by NE and NE-stimulated /sup 45/Ca efflux was markedly nonlinear, such that 50% of maximum NE-stimulated efflux occurred with occupancy of only approximately 7% of receptors. These two experimental approaches provide direct evidence for the presence in cultured rabbit aortic smooth muscle cells of a sizable pool of alpha 1-adrenergic receptors in excess of those needed for maximum NE-stimulated /sup 45/Ca efflux. This evidence of ''spare'' receptors, together with the finding of two affinity states of agonist binding, raises the possibility of functional heterogeneity of alpha 1-adrenergic receptors in this system.

  17. Macrophage secretory products selectively stimulate dermatan sulfate proteoglycan production in cultured arterial smooth muscle cells.

    PubMed Central

    Edwards, I. J.; Wagner, W. D.; Owens, R. T.

    1990-01-01

    Arterial dermatan sulfate proteoglycan has been shown to increase with atherosclerosis progression, but factors responsible for this increase are unknown. To test the hypothesis that smooth muscle cell proteoglycan synthesis may be modified by macrophage products, pigeon arterial smooth muscle cells were exposed to the media of either cholesteryl ester-loaded pigeon peritoneal macrophages or a macrophage cell line P388D1. Proteoglycans radiolabeled with [35S]sulfate and [3H]serine were isolated from culture media and smooth muscle cells and purified following precipitation with 1-hexadecylpyridinium chloride and chromatography. Increasing concentrations of macrophage-conditioned media were associated with a dose-response increase in [35S]sulfate incorporation into secreted proteoglycans, but there was no change in cell-associated proteoglycans. Incorporation of [3H]serine into total proteoglycan core proteins was not significantly different (5.2 X 10(5) dpm and 5.5 X 10(5) disintegrations per minute (dpm) in control and conditioned media-treated cultures, respectively), but selective effects were observed on individual proteoglycan types. Twofold increases in dermatan sulfate proteoglycan and limited degradation of chondroitin sulfate proteoglycan were apparent based on core proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoinhibition studies indicated that interleukin-1 was involved in the modulation of proteoglycan synthesis by macrophage-conditioned media. These data provide support for the role of macrophages in alteration of the matrix proteoglycans synthesized by smooth muscle cells and provide a mechanism to account for the reported increased dermatan sulfate/chondroitin sulfate ratios in the developing atherosclerotic lesion. Images Figure 6 PMID:2316626

  18. Macrophage secretory products selectively stimulate dermatan sulfate proteoglycan production in cultured arterial smooth muscle cells

    SciTech Connect

    Edwards, I.J.; Wagner, W.D.; Owens, R.T. )

    1990-03-01

    Arterial dermatan sulfate proteoglycan has been shown to increase with atherosclerosis progression, but factors responsible for this increase are unknown. To test the hypothesis that smooth muscle cell proteoglycan synthesis may be modified by macrophage products, pigeon arterial smooth muscle cells were exposed to the media of either cholesteryl ester-loaded pigeon peritoneal macrophages or a macrophage cell line P388D1. Proteoglycans radiolabeled with (35S)sulfate and (3H)serine were isolated from culture media and smooth muscle cells and purified following precipitation with 1-hexadecylpyridinium chloride and chromatography. Increasing concentrations of macrophage-conditioned media were associated with a dose-response increase in (35S)sulfate incorporation into secreted proteoglycans, but there was no change in cell-associated proteoglycans. Incorporation of (3H)serine into total proteoglycan core proteins was not significantly different (5.2 X 10(5) dpm and 5.5 X 10(5) disintegrations per minute (dpm) in control and conditioned media-treated cultures, respectively), but selective effects were observed on individual proteoglycan types. Twofold increases in dermatan sulfate proteoglycan and limited degradation of chondroitin sulfate proteoglycan were apparent based on core proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoinhibition studies indicated that interleukin-1 was involved in the modulation of proteoglycan synthesis by macrophage-conditioned media. These data provide support for the role of macrophages in alteration of the matrix proteoglycans synthesized by smooth muscle cells and provide a mechanism to account for the reported increased dermatan sulfate/chondroitin sulfate ratios in the developing atherosclerotic lesion.

  19. Electrical stimulation induces calcium-dependent up-regulation of neuregulin-1β in dystrophic skeletal muscle cell lines.

    PubMed

    Juretić, Nevenka; Jorquera, Gonzalo; Caviedes, Pablo; Jaimovich, Enrique; Riveros, Nora

    2012-01-01

    Duchenne muscular dystrophy (DMD) is a neuromuscular disease originated by reduced or no expression of dystrophin, a cytoskeletal protein that provides structural integrity to muscle fibres. A promising pharmacological treatment for DMD aims to increase the level of a structural dystrophin homolog called utrophin. Neuregulin-1 (NRG-1), a growth factor that potentiates myogenesis, induces utrophin expression in skeletal muscle cells. Microarray analysis of total gene expression allowed us to determine that neuregulin-1β (NRG-1β) is one of 150 differentially expressed genes in electrically stimulated (400 pulses, 1 ms, 45 Hz) dystrophic human skeletal muscle cells (RCDMD). We investigated the effect of depolarization, and the involvement of intracellular Ca(2+) and PKC isoforms on NRG-1β expression in dystrophic myotubes. Electrical stimulation of RCDMD increased NRG-1β mRNA and protein levels, and mRNA enhancement was abolished by actinomycin D. NRG-1β transcription was inhibited by BAPTA-AM, an intracellular Ca(2+) chelator, and by inhibitors of IP(3)-dependent slow Ca(2+) transients, like 2-APB, Ly 294002 and Xestospongin B. Ryanodine, a fast Ca(2+) signal inhibitor, had no effect on electrical stimulation-induced expression. BIM VI (general inhibitor of PKC isoforms) and Gö 6976 (specific inhibitor of Ca(2+)-dependent PKC isoforms) abolished NRG-1β mRNA induction. Our results suggest that depolarization induced slow Ca(2+) signals stimulate NRG-1β transcription in RCDMD cells, and that Ca(2+)-dependent PKC isoforms are involved in this process. Based on utrophin's ability to partially compensate dystrophin disfunction, knowledge on the mechanism involved on NRG-1 up-regulation could be important for new therapeutic strategies design.

  20. Mechanical Coupling of Smooth Muscle Cells Using Microengineered Substrates and Local Stimulation

    NASA Astrophysics Data System (ADS)

    Copeland, Craig; Hunter, David; Tung, Leslie; Chen, Christopher; Reich, Daniel

    2013-03-01

    Mechanical stresses directly affect many cellular processes, including signal transduction, growth, differentiation, and survival. Cells can themselves generate such stresses by activating myosin to contract the actin cytoskeleton, which in turn can regulate both cell-substrate and cell-cell interactions. We are studying mechanical forces at cell-cell and cell-substrate interactions using arrays of selectively patterned flexible PDMS microposts combined with the ability to apply local chemical stimulation. Micropipette ``spritzing'', a laminar flow technique, uses glass micropipettes mounted on a microscope stage to deliver drugs to controlled regions within a cellular construct while cell traction forces are recorded via the micropost array. The pipettes are controlled by micromanipulators allowing for rapid and precise movement across the array and the ability to treat multiple constructs within a sample. This technique allows for observing the propagation of a chemically induced mechanical stimulus through cell-cell and cell-substrate interactions. We have used this system to administer the acto-myosin inhibitors Blebbistatin and Y-27632 to single cells and observed the subsequent decrease in cell traction forces. Experiments using trypsin-EDTA have shown this system to be capable of single cell manipulation through removal of one cell within a pair configuration while leaving the other cell unaffected. This project is supported in part by NIH grant HL090747

  1. CD154-stimulated GM-CSF release by vascular smooth muscle cells elicits monocyte activation--role in atherogenesis.

    PubMed

    Stojakovic, Milica; Krzesz, Robert; Wagner, Andreas H; Hecker, Markus

    2007-11-01

    During the early phase of atherosclerosis, T cells and monocytes attach to and migrate through the endothelium into the vessel wall. To provide an insight into the potential cross talk between T cells and smooth muscle cells (SMC) in atherogenesis, we investigated changes in gene expression caused by CD40 ligation in cultured vascular SMC and their consequences for monocyte activation. CD40 expression in human-cultured SMC was induced by 24-h treatment with tumor necrosis factor-alpha plus interferon-gamma followed by 12-h exposure to mouse myeloma cells stably expressing human CD154 or the corresponding control cells. DNA microarray analysis (Affymetrix HG-U952A chip) indicated 33 up-regulated genes in three individual experiments of which 19 encoded pro-inflammatory adhesion molecules, cytokines, chemokines, and receptors. One functional consequence of this change in gene expression was an activation of transformed human promonocytic-1 monocytes exposed to the conditioned medium of the stimulated SMC. Subsequent antibody neutralization experiments identified granulocyte-macrophage colony-stimulating factor (GM-CSF) as the SMC-derived cytokine responsible for this effect. Thus, vascular SMC-like endothelial cells appear to contribute to the maintenance of an inflammatory response in the atherosclerotic vessel wall upon CD40-CD154 co-stimulation. Among 19 up-regulated pro-inflammatory gene products, GM-CSF plays an important role in SMC-dependent monocyte activation.

  2. Terbinafine: effects on platelet-derived growth factor-stimulated smooth muscle cells in vitro and myointimal proliferation in vivo

    SciTech Connect

    McCarthy, L.; Van Halen, R.G.; St. Denny, I.H.; Glinka, K.G.; Handley, D.A.; Stuetz, A.; Nemecek, G.M.

    1987-05-01

    Terbinafine (T; (E)-N-(6,6-dimethyl-2-hepten-4-ynyl)-N-methyl-1-naphthalenemethanamine), an antimycotic agent with antimitogenic activity in fibroblasts, was examined for its effects on platelet-derived growth factor (PDGF)-stimulated aortic smooth muscle cell DNA synthesis in vitro and myointimal proliferation in vivo. Exposure of smooth muscle cells to 1-25 ..mu..M T resulted in a concentration-dependent inhibition of PDGF-induced mitogenesis as determined by (/sup 3/H)thymidine incorporation or cell number. The IC/sub 50/ for T was approximately 5 ..mu..M. The inhibitory effect of terbinafine persisted in the presence of 0.4-8.0 ..mu..g/ml cholesterol or 130 ..mu..g/ml mevalonate. Administration of T to rats for 2 d before and 14 d after balloon catheter carotid injury resulted in a 40% decrease in lesion area. These observations indicate that T is both a potent in vitro antagonist of the smooth muscle cell mitogenic response to PDGF and an effective, well-tolerated, orally active inhibitor of myointimal proliferation in vivo.

  3. Chemerin Stimulates Vascular Smooth Muscle Cell Proliferation and Carotid Neointimal Hyperplasia by Activating Mitogen-Activated Protein Kinase Signaling

    PubMed Central

    Xiong, Wei; Luo, Yu; Wu, Lin; Liu, Feng; Liu, Huadong; Li, Jianghua; Liao, Bihong; Dong, Shaohong

    2016-01-01

    Vascular neointimal hyperplasia and remodeling arising from local inflammation are characteristic pathogeneses of proliferative cardiovascular diseases, such as atherosclerosis and post angioplasty restenosis. The molecular mechanisms behind these pathological processes have not been fully determined. The adipokine chemerin is associated with obesity, metabolism, and control of inflammation. Recently, chemerin has gained increased attention as it was found to play a critical role in the development of cardiovascular diseases. In this study, we investigated the effects of chemerin on the regulation of vascular smooth muscle cells and carotid neointimal formation after angioplasty. We found that circulating chemerin levels increased after carotid balloon injury, and that knockdown of chemerin significantly inhibited the proliferative aspects of vascular smooth muscle cells induced by platelet-derived growth factor-BB and pro-inflammatory chemokines in vitro as well as prohibited carotid neointimal hyperplasia and pro-inflammatory chemokines in vivo after angioplasty. Additionally, inhibition of chemerin down-regulated the expression of several proteins, including phosphorylated p38 mitogen-activated protein kinase, phosphorylated extracellular signal regulated kinase 1/2, nuclear factor-kappa B p65, and proliferation cell nuclear antigen. The novel finding of this study is that chemerin stimulated vascular smooth muscle cells proliferation and carotid intimal hyperplasia through activation of the mitogen-activated protein kinase signaling pathway, which may lead to vascular inflammation and remodeling, and is relevant to proliferative cardiovascular diseases. PMID:27792753

  4. AMPK activation by prolonged stimulation with interleukin-1β contributes to the promotion of GLUT4 translocation in skeletal muscle cells.

    PubMed

    Takaguri, Akira; Inoue, Saya; Kubo, Takashi; Satoh, Kumi

    2016-11-01

    Impaired insulin signaling in skeletal muscle cells causes insulin resistance associated with the onset of type 2 diabetes. Although interleukin (IL)-1β has been considered to be implicated in the pathogenesis of type 2 diabetes, the action of prolonged stimulation with IL-1β on the insulin signaling pathway in skeletal muscle cells remains poorly understood. In the current study, we investigated the effect of IL-1β stimulation on insulin signal transduction from the insulin receptor (IR), resulting in glucose transporter 4 (GLUT4) translocation in skeletal muscle cells. In L6-GLUT4myc cells, stimulation with IL-1β for 24 h promoted GLUT4 translocation to the plasma membrane and increased glucose uptake in a concentration-dependent manner, whereas short-term stimulation with IL-1 for up to 6 h did not affect that. In addition, stimulation with IL-1β for 24 h further increased insulin-stimulated GLUT4 translocation. Interestingly, stimulation with IL-1β for 24 h did not cause any change in the phosphorylation of insulin signal molecules IR, insulin receptor substrate (IRS)-1, Akt, and p21-activated kinase (PAK1). Stimulation with IL-1β for 24 h significantly increased AMP-activated protein kinase (AMPK) phosphorylation and GLUT4 protein expression. Small interfering RNA (siRNA) targeting AMPK1/2 significantly inhibited IL-1β-stimulated GLUT4 translocation. These results suggest that prolonged stimulation with IL-1β positively regulates GLUT4 translocation in skeletal muscle cells. IL-1β may have a beneficial effect on maintaining glucose homeostasis in skeletal muscle cells in patients with type 2 diabetes. .

  5. Store depletion induces Gαq-mediated PLCβ1 activity to stimulate TRPC1 channels in vascular smooth muscle cells

    PubMed Central

    Shi, Jian; Miralles, Francesc; Birnbaumer, Lutz; Large, William A.; Albert, Anthony P.

    2016-01-01

    Depletion of sarcoplasmic reticulum (SR) Ca2+ stores activates store-operated channels (SOCs) composed of canonical transient receptor potential (TRPC) 1 proteins in vascular smooth muscle cells (VSMCs), which contribute to important cellular functions. We have previously shown that PKC is obligatory for activation of TRPC1 SOCs in VSMCs, and the present study investigates if the classic phosphoinositol signaling pathway involving Gαq-mediated PLC activity is responsible for driving PKC-dependent channel gating. The G-protein inhibitor GDP-β-S, anti-Gαq antibodies, the PLC inhibitor U73122, and the PKC inhibitor GF109203X all inhibited activation of TRPC1 SOCs, and U73122 and GF109203X also reduced store-operated PKC-dependent phosphorylation of TRPC1 proteins. Three distinct SR Ca2+ store-depleting agents, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester, cyclopiazonic acid, and N,N,N′,N′-tetrakis(2-pyridylmethyl)ethane-1,2-diamineed, induced translocations of the fluorescent biosensor GFP-PLCδ1-PH from the cell membrane to the cytosol, which were inhibited by U73122. Knockdown of PLCβ1 with small hairpin RNA reduced both store-operated PLC activity and stimulation of TRPC1 SOCs. Immunoprecipitation studies and proximity ligation assays revealed that store depletion induced interactions between TRPC1 and Gαq, and TRPC1 and PLCβ1. We propose a novel activation mechanism for TRPC1 SOCs in VSMCs, in which store depletion induces formation of TRPC1-Gαq-PLCβ1 complexes that lead to PKC stimulation and channel gating.—Shi, J., Miralles, F., Birnbaumer, L., Large, W. A., Albert, A. P. Store depletion induces Gαq-mediated PLCβ1 activity to stimulate TRPC1 channels in vascular smooth muscle cells. PMID:26467792

  6. The Oligo Fucoidan Inhibits Platelet-Derived Growth Factor-Stimulated Proliferation of Airway Smooth Muscle Cells.

    PubMed

    Yang, Chao-Huei; Tsao, Chiung-Fang; Ko, Wang-Sheng; Chiou, Ya-Ling

    2016-01-09

    In the pathogenesis of asthma, the proliferation of airway smooth muscle cells (ASMCs) is a key factor in airway remodeling and causes airway narrowing. In addition, ASMCs are also the effector cells of airway inflammation. Fucoidan extracted from marine brown algae polysaccharides has antiviral, antioxidant, antimicrobial, anticlotting, and anticancer properties; however, its effectiveness for asthma has not been elucidated thus far. Platelet-derived growth factor (PDGF)-treated primary ASMCs were cultured with or without oligo-fucoidan (100, 500, or 1000 µg/mL) to evaluate its effects on cell proliferation, cell cycle, apoptosis, and Akt, ERK1/2 signaling pathway. We found that PDGF (40 ng/mL) increased the proliferation of ASMCs by 2.5-fold after 48 h (p < 0.05). Oligo-fucoidan reduced the proliferation of PDGF-stimulated ASMCs by 75%-99% after 48 h (p < 0.05) and induced G₁/G₀ cell cycle arrest, but did not induce apoptosis. Further, oligo-fucoidan supplementation reduced PDGF-stimulated extracellular signal-regulated kinase (ERK1/2), Akt, and nuclear factor (NF)-κB phosphorylation. Taken together, oligo-fucoidan supplementation might reduce proliferation of PDGF-treated ASMCs through the suppression of ERK1/2 and Akt phosphorylation and NF-κB activation. The results provide basis for future animal experiments and human trials.

  7. The Oligo Fucoidan Inhibits Platelet-Derived Growth Factor-Stimulated Proliferation of Airway Smooth Muscle Cells

    PubMed Central

    Yang, Chao-Huei; Tsao, Chiung-Fang; Ko, Wang-Sheng; Chiou, Ya-Ling

    2016-01-01

    In the pathogenesis of asthma, the proliferation of airway smooth muscle cells (ASMCs) is a key factor in airway remodeling and causes airway narrowing. In addition, ASMCs are also the effector cells of airway inflammation. Fucoidan extracted from marine brown algae polysaccharides has antiviral, antioxidant, antimicrobial, anticlotting, and anticancer properties; however, its effectiveness for asthma has not been elucidated thus far. Platelet-derived growth factor (PDGF)-treated primary ASMCs were cultured with or without oligo-fucoidan (100, 500, or 1000 µg/mL) to evaluate its effects on cell proliferation, cell cycle, apoptosis, and Akt, ERK1/2 signaling pathway. We found that PDGF (40 ng/mL) increased the proliferation of ASMCs by 2.5-fold after 48 h (p < 0.05). Oligo-fucoidan reduced the proliferation of PDGF-stimulated ASMCs by 75%–99% after 48 h (p < 0.05) and induced G1/G0 cell cycle arrest, but did not induce apoptosis. Further, oligo-fucoidan supplementation reduced PDGF-stimulated extracellular signal-regulated kinase (ERK1/2), Akt, and nuclear factor (NF)-κB phosphorylation. Taken together, oligo-fucoidan supplementation might reduce proliferation of PDGF-treated ASMCs through the suppression of ERK1/2 and Akt phosphorylation and NF-κB activation. The results provide basis for future animal experiments and human trials. PMID:26761017

  8. Comparative proteome analysis of Tumor necrosis factor α-stimulated human Vascular Smooth Muscle Cells in response to melittin

    PubMed Central

    2013-01-01

    Background Bee venom has been used to relieve pain and to treat inflammatory diseases, including rheumatoid arthritis, in humans. To better understand the mechanisms of the anti-inflammatory and anti-atherosclerosis effect of bee venom, gel electrophoresis and mass spectrometry were used to identify proteins whose expression was altered in human Vascular Smooth Muscle Cells (hVSMCs) stimulated by tumor necrosis factor alpha after 12 h in the presence of melittin. Results To obtain valuable insights into the anti-inflammatory and anti-atherosclerosis mechanisms of melittin, two-dimensional (2-D) gel electrophoresis and MALDI-TOF/TOF were used. The proteome study, we showed 33 significant proteins that were differentially expressed in the cells treated with tumor necrosis factor alpha and melittin. Thirteen proteins were significantly increased in the cells treated with tumor necrosis factor alpha, and those proteins were reduced in the cells treated with melittin. Five of the proteins that showed increased expression in the cells treated with tumor necrosis factor alpha are involved in cell migration, including calreticulin, an essential factor of development that plays a role in transcription regulation. The proteins involved in cell migration were reduced in the melittin treated cells. The observed changes in the expression of GRP75, prohibitin, and a select group of other proteins were validated with reverse transcribed-PCR. It was confirmed that the observed change in the protein levels reflected a change in the genes level. In addition, the phosphorylation of EGFR and ERK was validated by analyzing the protein pathway. Conclusion Taken together, these data established that the expression of some proteins was significantly changed by melittin treatment in tumor necrosis factor alpha stimulated the cells and provided insights into the mechanism of the melittin function for its potential use as an anti-inflammatory agent. PMID:23651618

  9. AMP-activated protein kinase stimulates Warburg-like glycolysis and activation of satellite cells during muscle regeneration.

    PubMed

    Fu, Xing; Zhu, Mei-Jun; Dodson, Mike V; Du, Min

    2015-10-30

    Satellite cells are the major myogenic stem cells residing inside skeletal muscle and are indispensable for muscle regeneration. Satellite cells remain largely quiescent but are rapidly activated in response to muscle injury, and the derived myogenic cells then fuse to repair damaged muscle fibers or form new muscle fibers. However, mechanisms eliciting metabolic activation, an inseparable step for satellite cell activation following muscle injury, have not been defined. We found that a noncanonical Sonic Hedgehog (Shh) pathway is rapidly activated in response to muscle injury, which activates AMPK and induces a Warburg-like glycolysis in satellite cells. AMPKα1 is the dominant AMPKα isoform expressed in satellite cells, and AMPKα1 deficiency in satellite cells impairs their activation and myogenic differentiation during muscle regeneration. Drugs activating noncanonical Shh promote proliferation of satellite cells, which is abolished because of satellite cell-specific AMPKα1 knock-out. Taken together, AMPKα1 is a critical mediator linking noncanonical Shh pathway to Warburg-like glycolysis in satellite cells, which is required for satellite activation and muscle regeneration.

  10. Nitric oxide production by cultured human aortic smooth muscle cells: stimulation by fluid flow

    NASA Technical Reports Server (NTRS)

    Papadaki, M.; Tilton, R. G.; Eskin, S. G.; McIntire, L. V.

    1998-01-01

    This study demonstrated that exposure of cultured human aortic smooth muscle cells (SMC) to fluid flow resulted in nitric oxide (NO) production, monitored by nitrite and guanosine 3',5'-cyclic monophosphate production. A rapid burst in nitrite production rate was followed by a more gradual increase throughout the period of flow exposure. Neither the initial burst nor the prolonged nitrite production was dependent on the level of shear stress in the range of 1.1-25 dyn/cm2. Repeated exposure to shear stress after a 30-min static period restimulated nitrite production similar to the initial burst. Ca(2+)-calmodulin antagonists blocked the initial burst in nitrite release. An inhibitor of nitric oxide synthase (NOS) blocked nitrite production, indicating that changes in nitrite reflect NO production. Treatment with dexamethasone or cycloheximide had no effect on nitrite production. Monoclonal antibodies directed against the inducible and endothelial NOS isoforms showed no immunoreactivity on Western blots, whereas monoclonal antibodies directed against the neuronal NOS gave specific products. These findings suggest that human aortic SMC express a constitutive neuronal NOS isoform, the enzymatic activity of which is modulated by flow.

  11. Carnosic acid as a component of rosemary extract stimulates skeletal muscle cell glucose uptake via AMPK activation.

    PubMed

    Naimi, Madina; Vlavcheski, Filip; Murphy, Brennan; Hudlicky, Tomas; Tsiani, Evangelia

    2017-01-01

    Compounds that increase the activity of the energy sensor AMP-activated kinase (AMPK) have the potential to regulate blood glucose levels. Although rosemary extract (RE) has been reported to activate AMPK and reduce blood glucose levels in vivo, the chemical components responsible for these effects are not known. In the present study, we measured the levels of the polyphenol carnosic acid (CA) in RE and examined the effects and the mechanism of action of CA on glucose transport system in muscle cells. High performance liquid chromatography (HPLC) was used to measure the levels of CA in RE. Parental and GLUT4myc or GLUT1myc overexpressing L6 rat myotubes were used. Glucose uptake was assessed using [(3) H]-2-deoxy-d-glucose. Total and phosphorylated levels of Akt and AMPK were measured by immunoblotting. Plasma membrane GLUT4myc and GLUT1myc levels were examined using a GLUT translocation assay. Statistics included analysis of variance (ANOVA) followed by Tukey's post-hoc test. At concentrations found in rosemary extract, CA stimulated glucose uptake in L6 myotubes. At 2.0 μmol/L CA a response (226 ± 9.62% of control, P=.001), similar to maximum insulin (201 ± 7.86% of control, P=.001) and metformin (213 ± 10.74% of control, P=.001) was seen. Akt phosphorylation was not affected by CA while AMPK and ACC phosphorylation was increased and the CA-stimulated glucose uptake was significantly reduced by the AMPK inhibitor compound C. Plasma membrane GLUT4 or GLUT1 glucose transporter levels were not affected by CA. Our study shows increased muscle cell glucose uptake and AMPK activation by low CA concentrations, found in rosemary extract, indicating that CA may be responsible for the antihyperglycemic properties of rosemary extract seen in vivo.

  12. Phosphatidylcholine is a major source of phosphatidic acid and diacylglycerol in angiotensin II-stimulated vascular smooth-muscle cells.

    PubMed

    Lassègue, B; Alexander, R W; Clark, M; Akers, M; Griendling, K K

    1993-06-01

    In cultured vascular smooth-muscle cells, angiotensin II produces a sustained formation of diacylglycerol (DG) and phosphatidic acid (PtdOH). Since the fatty acid composition of these molecules is likely to determine their efficacy as second messengers, it is important to ascertain the phospholipid precursors and the biochemical pathways from which they are produced. Our experiments suggest that phospholipase D (PLD)-mediated phosphatidylcholine (PtdCho) hydrolysis is the major source of both DG and PtdOH during the late signalling phase. First, in cells labelled with [3H]myristate, which preferentially labels PtdCho, formation of [3H]PtdOH precedes formation of [3H]DG. Second, in contrast with phospholipase C (PLC) activation, DG mass accumulation is dependent on extracellular Ca2+. Similarly, DG mass accumulation is not attenuated by protein kinase C activation, which we have previously shown to inhibit the phosphoinositide-specific PLC. Third, the fatty acid composition of late-phase DG and PtdOH more closely resembles that of PtdCho than that of phosphatidylinositol. Finally, in cells labelled for a short time with [3H]glycerol, the radioactivity incorporated into [3H]DG and PtdOH was greater than that incorporated into PtdIns, but not into PtdCho. We found no evidence that synthesis de novo or phosphatidylethanolamine breakdown contributes to sustained DG and PtdOH formation. Thus, in angiotensin II-stimulated cultured vascular smooth-muscle cells, PLD-mediated PtdCho hydrolysis is the major source of sustained DG and PtdOH, whereas phosphoinositide breakdown is a minor contributor. Furthermore, PtdOH phosphohydrolase, which determines the relative levels of DG and PtdOH, appears to be regulated by protein kinase C. These results have important implications for the role of these second messengers in growth and contraction.

  13. Neuromuscular Electrical Stimulation for Skeletal Muscle Function

    PubMed Central

    Doucet, Barbara M.; Lam, Amy; Griffin, Lisa

    2012-01-01

    Lack of neural innervation due to neurological damage renders muscle unable to produce force. Use of electrical stimulation is a medium in which investigators have tried to find a way to restore movement and the ability to perform activities of daily living. Different methods of applying electrical current to modify neuromuscular activity are electrical stimulation (ES), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and functional electrical stimulation (FES). This review covers the aspects of electrical stimulation used for rehabilitation and functional purposes. Discussed are the various parameters of electrical stimulation, including frequency, pulse width/duration, duty cycle, intensity/amplitude, ramp time, pulse pattern, program duration, program frequency, and muscle group activated, and how they affect fatigue in the stimulated muscle. PMID:22737049

  14. Growth hormone stimulates protein synthesis in bovine skeletal muscle cells without altering insulin-like growth factor-I mRNA expression.

    PubMed

    Ge, X; Yu, J; Jiang, H

    2012-04-01

    Growth hormone is a major stimulator of skeletal muscle growth in animals, including cattle. In this study, we determined whether GH stimulates skeletal muscle growth in cattle by direct stimulation of proliferation or fusion of myoblasts, by direct stimulation of protein synthesis, or by direct inhibition of protein degradation in myotubes. We also determined whether these direct effects of GH are mediated by IGF-I produced by myoblasts or myotubes. Satellite cells were isolated from cattle skeletal muscle and were allowed to proliferate as myoblasts or induced to fuse into myotubes in culture. Growth hormone at 10 and 100 ng/mL increased protein synthesis in myotubes (P < 0.05), but had no effect on protein degradation in myotubes or proliferation of myoblasts (P > 0.05). Insulin-like growth factor-I at 50 and 500 ng/mL stimulated protein synthesis (P < 0.01), and this effect of IGF-I was much greater than that of GH (P < 0.05). Besides stimulating protein synthesis, IGF-I at 50 and 500 ng/mL also inhibited protein degradation in myotubes (P < 0.01), and IGF-I at 500 ng/mL stimulated proliferation of myoblasts (P < 0.05). Neither GH nor IGF-I had effects on fusion of myoblasts into myotubes (P > 0.1). These data indicate that GH and IGF-I have largely different direct effects on bovine muscle cells. Growth hormone at 10 and 100 ng/mL had no effect on IGF-I mRNA expression in either myoblasts or myotubes (P > 0.1). This lack of effect was not because the cultured myoblasts or myotubes were not responsive to GH; GH receptor mRNA was detectable in them and the expression of the cytokine-inducible SH2-containing protein (CISH) gene, a well-established GH target gene, was increased by GH in bovine myoblasts (P < 0.05). Overall, the data suggest that GH stimulates skeletal muscle growth in cattle in part through stimulation of protein synthesis in the muscle and that this stimulation is not mediated through increased IGF-I mRNA expression in the muscle.

  15. Myricitrin inhibits PDGF-BB-stimulated vascular smooth muscle cell proliferation and migration through suppressing PDGFRβ/Akt/Erk signaling.

    PubMed

    Li, Jie; Zhang, Mei; Ma, Juanjuan

    2015-01-01

    Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) and the stimulation of platelet-derived growth factor (PDGF)-BB play major pathological processes involved in the development of cardiovascular diseases. As a result, the use of anti-proliferative and anti-migratory agents for VSMCs offers promise for the treatment of vascular disorders. Myricitrin is a naturally occurring phenolic compound which possesses antioxidant and anti-inflammatory activity. In this study, we investigate the inhibitory effect of myricitrin on PDGF-BB-induced VSMCs proliferation and migration. In accordance with these findings, myricitrin induced the arrest of cell cycle progression at G0/G1 phase. Myricitrin also decreased the expressions of G0/G1 specific regulatory proteins including cyclin D1, cyclin-dependent kinases (CDK) 4, cyclin E and CDK2, as well as increased the expression of p21 in PDGF-BB-induced VSMCs. Moreover, myricitrin inhibited PDGF-BB-induced phosphorylation of PDGFRβ, Akt and Erk1/2. These results suggest that myricitrin plays an important role in prevention of VSMCs proliferation and migration through the G0/G1 cell cycle arrest by PDGF signaling pathway. Thus, myricitrin is effective in reducing atherosclerotic process by blocking proliferation of VSMCs.

  16. Efficient generation of smooth muscle cells from adipose-derived stromal cells by 3D mechanical stimulation can substitute the use of growth factors in vascular tissue engineering.

    PubMed

    Parvizi, Mojtaba; Bolhuis-Versteeg, Lydia A M; Poot, André A; Harmsen, Martin C

    2016-07-01

    Occluding artery disease causes a high demand for bioartificial replacement vessels. We investigated the combined use of biodegradable and creep-free poly (1,3-trimethylene carbonate) (PTMC) with smooth muscle cells (SMC) derived by biochemical or mechanical stimulation of adipose tissue-derived stromal cells (ASC) to engineer bioartificial arteries. Biochemical induction of cultured ASC to SMC was done with TGF-β1 for 7d. Phenotype and function were assessed by qRT-PCR, immunodetection and collagen contraction assays. The influence of mechanical stimulation on non-differentiated and pre-differentiated ASC, loaded in porous tubular PTMC scaffolds, was assessed after culturing under pulsatile flow for 14d. Assays included qRT-PCR, production of extracellular matrix and scanning electron microscopy. ASC adhesion and TGF-β1-driven differentiation to contractile SMC on PTMC did not differ from tissue culture polystyrene controls. Mesenchymal and SMC markers were increased compared to controls. Interestingly, pre-differentiated ASC had only marginal higher contractility than controls. Moreover, in 3D PTMC scaffolds, mechanical stimulation yielded well-aligned ASC-derived SMC which deposited ECM. Under the same conditions, pre-differentiated ASC-derived SMC maintained their SMC phenotype. Our results show that mechanical stimulation can replace TGF-β1 pre-stimulation to generate SMC from ASC and that pre-differentiated ASC keep their SMC phenotype with increased expression of SMC markers.

  17. Tissue factor expression in human arterial smooth muscle cells. TF is present in three cellular pools after growth factor stimulation.

    PubMed Central

    Schecter, A D; Giesen, P L; Taby, O; Rosenfield, C L; Rossikhina, M; Fyfe, B S; Kohtz, D S; Fallon, J T; Nemerson, Y; Taubman, M B

    1997-01-01

    Tissue factor (TF) is a transmembrane glycoprotein that initiates the coagulation cascade. Because of the potential role of TF in mediating arterial thrombosis, we have examined its expression in human aortic and coronary artery smooth muscle cells (SMC). TF mRNA and protein were induced in SMC by a variety of growth agonists. Exposure to PDGF AA or BB for 30 min provided all of the necessary signals for induction of TF mRNA and protein. This result was consistent with nuclear runoff analyses, demonstrating that PDGF-induced TF transcription occurred within 30 min. A newly developed assay involving binding of digoxigenin-labeled FVIIa (DigVIIa) and digoxigenin-labeled Factor X (DigX) was used to localize cellular TF. By light and confocal microscopy, prominent TF staining was seen in the perinuclear cytoplasm beginning 2 h after agonist treatment and persisting for 10-12 h. Surface TF activity, measured on SMC monolayers under flow conditions, increased transiently, peaking 4-6 h after agonist stimulation and returning to baseline within 16 h. Peak surface TF activity was only approximately 20% of total TF activity measured in cell lysates. Surface TF-blocking experiments demonstrated that the remaining TF was found as encrypted surface TF, and also in an intracellular pool. The relatively short-lived surface expression of TF may be critical for limiting the thrombotic potential of intact SMC exposed to growth factor stimulation. In contrast, the encrypted surface and intracellular pools may provide a rich source of TF under conditions associated with SMC damage, such as during atherosclerotic plaque rupture or balloon arterial injury. PMID:9410905

  18. Reflex inhibition of cutaneous and muscle vasoconstrictor neurons during stimulation of cutaneous and muscle nociceptors.

    PubMed

    Kirillova-Woytke, Irina; Baron, Ralf; Jänig, Wilfrid

    2014-05-01

    Cutaneous (CVC) and muscle (MVC) vasoconstrictor neurons exhibit typical reflex patterns to physiological stimulation of somatic and visceral afferent neurons. Here we tested the hypothesis that CVC neurons are inhibited by stimulation of cutaneous nociceptors but not of muscle nociceptors and that MVC neurons are inhibited by stimulation of muscle nociceptors but not of cutaneous nociceptors. Activity in the vasoconstrictor neurons was recorded from postganglionic axons isolated from the sural nerve or the lateral gastrocnemius-soleus nerve in anesthetized rats. The nociceptive afferents were excited by mechanical stimulation of the toes of the ipsilateral hindpaw (skin), by hypertonic saline injected into the ipsi- or contralateral gastrocnemius-soleus muscle, or by heat or noxious cold stimuli applied to the axons in the common peroneal nerve or tibial nerve. The results show that CVC neurons are inhibited by noxious stimulation of skin but not by noxious stimulation of skeletal muscle and that MVC neurons are inhibited by noxious stimulation of skeletal muscle but not by noxious stimulation of skin. These inhibitory reflexes are mostly lateralized and are most likely organized in the spinal cord. Stimulation of nociceptive cold-sensitive afferents does not elicit inhibitory or excitatory reflexes in CVC or MVC neurons. The reflex inhibition of activity in CVC or MVC neurons generated by stimulation of nociceptive cutaneous or muscle afferents during tissue injury leads to local increase of blood flow, resulting in an increase of transport of immunocompetent cells, proteins, and oxygen to the site of injury and enhancing the processes of healing.

  19. Increasing leucine concentration stimulates mechanistic target of rapamycin signaling and cell growth in C2C12 skeletal muscle cells.

    PubMed

    Areta, José L; Hawley, John A; Ye, Ji-Ming; Chan, M H Stanley; Coffey, Vernon G

    2014-11-01

    Leucine is a key amino acid for initiating translation in muscle cells, but the dose-dependent effects of leucine on intracellular signaling are poorly characterized. This study examined the effect that increasing doses of leucine would have on changes in mechanistic target of rapamycin (mTOR)-mediated signaling, rates of protein synthesis, and cell size in C2C12 cells. We hypothesized that a leucine "threshold" exists, which represents the minimum stimulus required to initiate mTOR signaling in muscle cells. Acute exposure to 1.5, 3.2, 5.0, and 16.1 mM leucine increased phosphorylation of mTOR(Ser2448) (~1.4-fold; P < .04), 4E-BP1 (Thr37/46) (~1.9-fold; P < .001), and rpS6(Ser235/6) (~2.3-fold; P < .001). However, only p70S6k(Thr389) exhibited a dose-dependent response to leucine with all treatments higher than control (~4-fold; P < .001) and at least 5 mM higher than the 1.5-mM concentration (1.2-fold; P < .02). Rates of protein synthesis were not altered by any treatment. Seven days of exposure to 0.5, 1.5, 5.0, and 16.5 mM leucine resulted in an increase in cell size in at least 5 mM treatments (~1.6-fold, P < .001 vs control). Our findings indicate that even at low leucine concentrations, phosphorylation of proteins regulating translation initiation signaling is enhanced. The phosphorylation of p70S6k(Thr389) follows a leucine dose-response relationship, although this was not reflected by the acute protein synthetic response. Nevertheless, under the conditions of the present study, it appears that leucine concentrations of at least 5 mM are necessary to enhance cell growth.

  20. Effects of extracellular acid stimulation on rat vascular smooth muscle cell in Gas6/Axl or PI3K/Akt signaling pathway.

    PubMed

    Cui, Liwen; Bai, Yaling; Zhang, Junxia; Zhang, Shenglei; Xu, Jinsheng

    Recent studies have indicated that extracellular acid stimulation inhibited the calcification of vascular smooth muscle cells (VSMCs). Cell apoptosis played an important role in the occurrence and development of vascular calcification. We further explored the effects of Gas6/Axl or PI3K/Akt signaling pathway on the inhibition of rat VSMCs calcification in response to extracellular acid stimulation. Our study demonstrated that a high concentration of phosphorus induced apoptosis and calcification of VSMCs, decreased expression of Axl, and reduced phosphorylation of Akt. Stimulation of extracellular acid counteracted the effects as above by increasing the expression of Axl and Akt phosphorylation and decreasing the expression of activated Caspase3, which thereby decreased cell apoptosis and calcification. Moreover, the effects can be attenuated by PI3K inhibitor. Our study proved that extracellular acid stimulation played a vital role in the inhibition of rat VSMCs calcification and apoptosis in Gas6/Axl or PI3K/Akt signaling pathway.

  1. Cholera toxin treatment of vascular smooth muscle cells decreases smooth muscle α-actin content and abolishes the platelet-derived growth factor-BB-stimulated DNA synthesis

    PubMed Central

    Sachinidis, Agapios; Seul, Claudia; Gouni-Berthold, Ioanna; Seewald, Stefan; Ko, Yon; Vetter, Hans; Fingerle, Jürgen; Hoppe, Jürgen

    2000-01-01

    The second messenger cyclic AMP regulates diverse biological processes such as cell morphology and cell growth. We examined the role of the second messenger cyclic AMP on rat aortic vascular smooth muscle cell (VSMC) morphology and the intracellular transduction pathway mediated by platelet-derived growth factor β-receptor (PDGF-Rβ). The effect of PDGF-BB on VSMCs growth was assessed by [3H]-thymidine incorporation. Tyrosine phosphorylation of PDGF-Rβ, PLC-γ1, ERK1 and ERK2, p125FAK and paxillin as well as Sm α-actin was examined by the chemiluminescence Western blotting method. Actin mRNA level was quantitated by Northern blotting. Visualization of Sm α-actin filaments, paxillin and PDGF-Rβ was performed by immunfluorescence microscopy. Cholera toxin (CTX; 10 nM) treatment lead to a large and sustained increase in the cyclic AMP concentration after 2 h which correlated with change of VSMC morphology including complete disruption of the Sm α-actin filament array and loss of focal adhesions. Treatment of VSMCs with CTX did not influence tyrosine phosphorylation of p125FAK and paxillin but decreased the content of a Sm α-actin protein. Maximal decrease of 70% was observed after 24 h of treatment. CTX also caused a 90% decrease of the actin mRNA level. CTX treatment completely abolished PDGF-BB stimulated DNA-synthesis although PDGF-Rβ level and subcellular distribution and translocation was not altered. Furthermore CTX attenuated the PDGF-BB-induced tyrosine phosphorylation of the PDGF-Rβ, PI 3′-K, PLC-γ1 and ERK1/2 indicating an action of cyclic AMP on PDGF-β receptor. We conclude that although cyclic AMP attenuates the PDGF-Rβ mediated intracellular transduction pathway, an intact actin filament may be required for the PDGF-BB-induced DNA synthesis in VSMCs. PMID:10928958

  2. Cultured muscle cells from insulin-resistant type 2 diabetes patients have impaired insulin, but normal 5-amino-4-imidazolecarboxamide riboside-stimulated, glucose uptake.

    PubMed

    McIntyre, E A; Halse, R; Yeaman, S J; Walker, M

    2004-07-01

    Impaired insulin action is a characteristic feature of type 2 diabetes. The study aims were to investigate whether after prolonged culture skeletal muscle cultures from insulin-resistant, type 2 diabetic patients (taking >100 U insulin/d) displayed impaired insulin signaling effects compared with cultures from nondiabetic controls and to determine whether retained abnormalities were limited to insulin action by studying an alternative pathway of stimulated glucose uptake. Studies were performed on myotubes differentiated for 7 d between passages 4 and 6. Insulin-stimulated glucose uptake (100 nm; P < 0.05) and insulin-stimulated glycogen synthesis (1 nm; P < 0.01) were significantly impaired in the diabetic vs. control cultures. Protein kinase B (PKB) expression and phosphorylated PKB levels in response to insulin stimulation (20 nm) were comparable in the diabetic and control cultures. 5-Amino-4-imidazolecarboxamide riboside (AICAR) mimics the effect of exercise on glucose uptake by activating AMP-activated protein kinase. There was no difference in AICAR (2 mm)-stimulated glucose uptake between diabetic vs. control myotube cultures (P = not significant). In conclusion, diabetic muscle cultures retain signaling defects after prolonged culture that appear specific to the insulin signaling pathway, but not involving PKB. This supports an intrinsic abnormality of the diabetic muscle cells that is most likely to have a genetic basis.

  3. Ribozyme-mediated gene knock down strategy to dissect the consequences of PDGF stimulation in vascular smooth muscle cells

    PubMed Central

    2012-01-01

    Background Vascular Smooth Muscle Cells (VSMCs), due to their plasticity and ability to shift from a physiological contractile-quiescent phenotype to a pathological proliferating-activated status, play a central role in the onset and progression of atherosclerosis and cardiovascular diseases. PDGF-BB, among a series of cytokines and growth factors, has been identified as the critical factor in this phenotypic switch. In order to obtain new insights on the molecular effects triggered by PDGF-BB, a hammerhead ribozyme targeting the membrane receptor PDGFR-β was applied to inhibit PDGF pathway in porcine VSMCs. Findings Ribozymes, loaded on a cationic polymer-based vehicle, were delivered into cultured VSMCs. A significant impairment of the activation mechanisms triggered by PDGF-BB was demonstrated since cell migration decreased after treatments. In order to functionally validate the effects of PDGFR-β partial knock down we focused on the phosphorylation status of two proteins, protein disulfide isomerase-A3 (PDI-A3) and heat shock protein-60 (HSP-60), previously identified as indicative of VSMC phenotypic switch after PDGF-BB stimulation. Interestingly, while PDI-A3 phosphorylation was counteracted by the ribozyme administration indicating that PDI-A3 is a factor downstream the receptor signalling cascade, the HSP-60 phosphorylation status was greatly increased by the ribozyme administration. Conclusion These contradictory observations suggested that PDGF-BB might trigger different parallel pathways that could be modulated by alternative isoforms of the receptors for the growth factor. In conclusion the knock down strategy here described enables to discriminate between two tightly intermingled pathways. Moreover it opens new attractive perspectives in functional investigations where combined gene knock down and proteomic technologies would allow the identification of key factors and pathways involved in VSMC-linked pathological disorders. PMID:22676333

  4. Stimulation of 45Ca efflux from smooth muscle cells by metabolic inhibition and high K depolarization.

    PubMed

    Van Breemen, C; Wuytack, F; Casteels, R; Martinelli, B; Campailla, E; Ferrari, G

    1975-09-09

    The characteristics of the extracellular and cellular calcium exchange in taenia coli have been studied by efflux experiments under different experimental conditions. The exchange of extracellularly bound calcium is accelerated by the presence of calcium in the external solution. If a Ca-free solution is used as washing solution, the slowly exchanging extracellular calcium also contributes appreciably to the later phase of the Ca efflux and obscures the changes of the cellular calcium exchange. There is no evidence for a Ca-Ca exchange diffusion. Most of the 45Ca bound at extracellular binding sites can be released by a 10 min exposure to 2 mM EGTA or to 10 mM La3+. This La concentration moreover largely inhibits the release of 45Ca from the cellular compartment by metabolic depletion. A release of cellular 45Ca can be induced by metabolic depletion or by K depolarization. Both procedures probably act at the same sequestering sites. However, while DNP + IAAa cts in the absence of external Ca, it is observed that K depolarization can only cause a Ca release if external Ca can enter the cells.

  5. Increased beta-oxidation in muscle cells enhances insulin-stimulated glucose metabolism and protects against fatty acid-induced insulin resistance despite intramyocellular lipid accumulation.

    PubMed

    Perdomo, German; Commerford, S Renee; Richard, Ann-Marie T; Adams, Sean H; Corkey, Barbara E; O'Doherty, Robert M; Brown, Nicholas F

    2004-06-25

    Skeletal muscle insulin resistance may be aggravated by intramyocellular accumulation of fatty acid-derived metabolites that inhibit insulin signaling. We tested the hypothesis that enhanced fatty acid oxidation in myocytes should protect against fatty acid-induced insulin resistance by limiting lipid accumulation. L6 myotubes were transduced with adenoviruses encoding carnitine palmitoyltransferase I (CPT I) isoforms or beta-galactosidase (control). Two to 3-fold overexpression of L-CPT I, the endogenous isoform in L6 cells, proportionally increased oxidation of the long-chain fatty acids palmitate and oleate and increased insulin stimulation of [(14)C]glucose incorporation into glycogen by 60% while enhancing insulin-stimulated phosphorylation of p38MAPK. Incubation of control cells with 0.2 mm palmitate for 18 h caused accumulation of triacylglycerol, diacylglycerol, and ceramide (but not long-chain acyl-CoA) and decreased insulin-stimulated [(14)C]glucose incorporation into glycogen (60%), [(3)H]deoxyglucose uptake (60%), and protein kinase B phosphorylation (20%). In the context of L-CPT I overexpression, palmitate preincubation produced a relative decrease in insulin-stimulated incorporation of [(14)C]glucose into glycogen (60%) and [(3)H]deoxyglucose uptake (40%) but did not inhibit phosphorylation of protein kinase B. Due to the enhancement of insulin-stimulated glucose metabolism induced by L-CPT I overexpression itself, net insulin-stimulated incorporation of [(14)C]glucose into glycogen and [(3)H]deoxyglucose uptake in L-CPT I-transduced, palmitate-treated cells were significantly greater than in palmitate-treated control cells (71 and 75% greater, respectively). However, L-CPT I overexpression failed to decrease intracellular triacylglycerol, diacylglycerol, ceramide, or long-chain acyl-CoA. We propose that accelerated beta-oxidation in muscle cells exerts an insulin-sensitizing effect independently of changes in intracellular lipid content.

  6. Stand-up exercise training facilitates muscle recovery from disuse atrophy by stimulating myogenic satellite cell proliferation in mice.

    PubMed

    Itoh, Yuta; Hayakawa, Kimihide; Mori, Tomohiro; Agata, Nobuhide; Inoue-Miyazu, Masumi; Murakami, Taro; Sokabe, Masahiro; Kawakami, Keisuke

    2014-11-01

    Determining the cellular and molecular recovery processes in inactivity - or unloading -induced atrophied muscles should improve rehabilitation strategies. We assessed the effects of stand-up exercise (SE) training on the recovery of atrophied skeletal muscles in male mice. Mice were trained to stand up and press an elevated lever in response to a light-tone cue preceding an electric foot shock and then subjected to tail suspension (TS) for 2 weeks to induce disuse atrophy in hind limb muscles. After release from TS, mice were divided into SE-trained (SE cues: 25 times per set, two sets per day) and non-SE-trained groups. Seven days after the training, average myofiber cross-sectional area (CSA) of the soleus muscle was significantly greater in the SE-trained group than in the non-SE-trained group (1843 ± 194 μm(2) vs. 1315 ± 153 μm(2)). Mean soleus muscle CSA in the SE trained group was not different from that in the CON group subjected to neither TS nor SE training (2005 ± 196 μm(2)), indicating that SE training caused nearly complete recovery from muscle atrophy. The number of myonuclei per myofiber was increased by ~60% in the SE-trained group compared with the non-SE-trained and CON groups (0.92 ± 0.03 vs. 0.57 ± 0.03 and 0.56 ± 0.11, respectively). The number of proliferating myonuclei, identified by 5-ethynyl-2'-deoxyuridine staining, increased within the first few days of SE training. Thus, it is highly likely that myogenic satellite cells proliferated rapidly in atrophied muscles in response to SE training and fused with existing myofibers to reestablish muscle mass.

  7. Leucine facilitates the insulin-stimulated glucose uptake and insulin signaling in skeletal muscle cells: involving mTORC1 and mTORC2.

    PubMed

    Liu, Hui; Liu, Rui; Xiong, Yufang; Li, Xiang; Wang, Xiaolei; Ma, Yan; Guo, Huailan; Hao, Liping; Yao, Ping; Liu, Liegang; Wang, Di; Yang, Xuefeng

    2014-08-01

    Leucine, a branched-chain amino acid, has been shown to promote glucose uptake and increase insulin sensitivity in skeletal muscle, but the exact mechanism remains unestablished. We addressed this issue in cultured skeletal muscle cells in this study. Our results showed that leucine alone did not have an effect on glucose uptake or phosphorylation of protein kinase B (AKT), but facilitated the insulin-induced glucose uptake and AKT phosphorylation. The insulin-stimulated glucose uptake and AKT phosphorylation were inhibited by the phosphatidylinositol 3-kinase inhibitor, wortmannin, but the inhibition was partially reversed by leucine. The inhibitor of mammalian target of rapamycin complex 1 (mTORC1), rapamycin, had no effect on the insulin-stimulated glucose uptake, but eliminated the facilitating effect of leucine in the insulin-stimulated glucose uptake and AKT phosphorylation. In addition, leucine facilitation of the insulin-induced AKT phosphorylation was neutralized by knocking down the core component of the mammalian target of rapamycin complex 2 (mTORC2) with specific siRNA. Together, these findings show that leucine can facilitate the insulin-induced insulin signaling and glucose uptake in skeletal muscle cells through both mTORC1 and mTORC2, implicating the potential importance of this amino acid in glucose homeostasis and providing new mechanistic insights.

  8. Leucine stimulation of skeletal muscle protein synthesis

    SciTech Connect

    Layman, D.K.; Grogan, C.K.

    1986-03-01

    Previous work in this laboratory has demonstrated a stimulatory effect of leucine on skeletal muscle protein synthesis measured in vitro during catabolic conditions. Studies in other laboratories have consistently found this effect in diaphragm muscle, however, studies examining effects on nitrogen balance or with in vivo protein synthesis in skeletal muscle are equivocal. This experiment was designed to determine the potential of leucine to stimulate skeletal muscle protein synthesis in vivo. Male Sprague-Dawley rats weighing 200 g were fasted for 12 hrs, anesthetized, a jugular cannula inserted, and protein synthesis measured using a primed continuous infusion of /sup 14/C-tyrosine. A plateau in specific activity was reached after 30 to 60 min and maintained for 3 hrs. The leucine dose consisted of a 240 umole priming dose followed by a continuous infusion of 160 umoles/hr. Leucine infusion stimulated protein synthesis in the soleus muscle (28%) and in the red (28%) and white portions (12%) of the gastrocnemius muscle compared with controls infused with only tyrosine. The increased rates of protein synthesis were due to increased incorporation of tyrosine into protein and to decreased specific activity of the free tyrosine pool. These data indicate that infusion of leucine has the potential to stimulate in vivo protein synthesis in skeletal muscles.

  9. Serotonin receptor-mediated stimulation of bovine smooth muscle cell prostacyclin synthesis and its modulation by platelet-derived growth factor.

    PubMed Central

    Coughlin, S R; Moskowitz, M A; Antoniades, H N; Levine, L

    1981-01-01

    Serotonin (5-hydroxytryptamine; 0.5 microM and above) stimulated the synthesis of prostacyclin (as measured by radioimmunoassay of 6-ketoprostaglandin F1 alpha) by bovine aortic smooth muscle cells in culture. This effect was structurally specific; a similar response was not elicited by the other indoles (tryptophan, n-acetylserotonin, 5-hydroxytryptophan, melatonin, or 5-hydroxyindoleacetic acid) or by the amines phenylephrine, isoproterenol, dopamine, or histamine). The response was reversible and was saturable at serotonin concentrations of 10 microM or higher. An increase in prostacyclin synthesis was elicited by the addition of a serotonin agonist, quipazine (1 microM and above), and antagonized by the serotonin receptor blockers cyproheptadine, methysergide, or methiothepin but not by other aminergic receptor-blocking drugs (e.g., phentolamine or propranolol). This effect was selective for cell type because serotonin or quipazine (100 microM) did not increase prostacyclin synthesis by bovine aortic endothelial cells. The addition of platelet-derived growth factor (PDGF) to cultures of smooth muscle cells dramatically enhanced prostacyclin synthesis in response to the coadministration of serotonin. PDGF greatly increased the maximum response to serotonin without altering the half-maximal effective concentration for serotonin. This synergistic interaction was blocked by the addition of a serotonin-receptor blocking agent. Taken together, these data suggest that serotonin stimulates smooth muscle prostacyclin synthesis through a specific receptor-mediated mechanism that can be modulated by PDGF. Images PMID:7031670

  10. NS-398, a selective COX-2 inhibitor, inhibits proliferation of IL-1{beta}-stimulated vascular smooth muscle cells by induction of {eta}{omicron}-1

    SciTech Connect

    Choi, Hyoung Chul; Kim, Hee Sun; Lee, Kwang Youn; Chang, Ki Churl Kang, Young Jin

    2008-11-28

    We investigated whether NS-398, a selective inhibitor of COX-2, induces HO-1 in IL-1{beta}-stimulated vascular smooth muscle cells (VSMC). NS-398 reduced the production of PGE{sub 2} without modulation of expression of COX-2 in IL-1{beta}-stimulated VSMC. NS-398 increased HO-1 mRNA and protein in a dose-dependent manner, but inhibited proliferation of IL-1{beta}-stimulated VSMC. Furthermore, SnPPIX, a HO-1 inhibitor, reversed the effects of NS-398 on PGE{sub 2} production, suggesting that COX-2 activity can be affected by HO-1. Hemin, a HO-1 inducer, also reduced the production of PGE{sub 2} and proliferation of IL-1{beta}-stimulated VSMC. CORM-2, a CO-releasing molecule, but not bilirubin inhibited proliferation of IL-1{beta}-stimulated VSMC. NS-398 inhibited proliferation of IL-1{beta}-stimulated VSMC in a HbO{sub 2}-sensitive manner. In conclusion, NS-398 inhibits proliferation of IL-1{beta}-stimulated VSMC by HO-1-derived CO. Thus, NS-398 may facilitate the healing process of vessels in vascular inflammatory disorders such as atherosclerosis.

  11. Calcineurin/nuclear factor of activated T cells-coupled vanilliod transient receptor potential channel 4 ca2+ sparklets stimulate airway smooth muscle cell proliferation.

    PubMed

    Zhao, Limin; Sullivan, Michelle N; Chase, Marlee; Gonzales, Albert L; Earley, Scott

    2014-06-01

    Proliferation of airway smooth muscle cells (ASMCs) contributes to the remodeling and irreversible obstruction of airways during severe asthma, but the mechanisms underlying this disease process are poorly understood. Here we tested the hypothesis that Ca(2+) influx through the vanilliod transient receptor potential channel (TRPV) 4 stimulates ASMC proliferation. We found that synthetic and endogenous TRPV4 agonists increase proliferation of primary ASMCs. Furthermore, we demonstrate that Ca(2+) influx through individual TRPV4 channels produces Ca(2+) microdomains in ASMCs, called "TRPV4 Ca(2+) sparklets." We also show that TRPV4 channels colocalize with the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin in ASMCs. Activated calcineurin dephosphorylates nuclear factor of activated T cells (NFAT) transcription factors cytosolic (c) to allow nuclear translocation and activation of synthetic transcriptional pathways. We show that ASMC proliferation in response to TRPV4 activity is associated with calcineurin-dependent nuclear translocation of the NFATc3 isoform tagged with green florescent protein. Our findings suggest that Ca(2+) microdomains created by TRPV4 Ca(2+) sparklets activate calcineurin to stimulate nuclear translocation of NFAT and ASMC proliferation. These findings further suggest that inhibition of TRPV4 could diminish asthma-induced airway remodeling.

  12. ROS Production via P2Y1-PKC-NOX2 Is Triggered by Extracellular ATP after Electrical Stimulation of Skeletal Muscle Cells

    PubMed Central

    Díaz-Vegas, Alexis; Campos, Cristian A.; Contreras-Ferrat, Ariel; Casas, Mariana; Buvinic, Sonja; Jaimovich, Enrique; Espinosa, Alejandra

    2015-01-01

    During exercise, skeletal muscle produces reactive oxygen species (ROS) via NADPH oxidase (NOX2) while inducing cellular adaptations associated with contractile activity. The signals involved in this mechanism are still a matter of study. ATP is released from skeletal muscle during electrical stimulation and can autocrinely signal through purinergic receptors; we searched for an influence of this signal in ROS production. The aim of this work was to characterize ROS production induced by electrical stimulation and extracellular ATP. ROS production was measured using two alternative probes; chloromethyl-2,7- dichlorodihydrofluorescein diacetate or electroporation to express the hydrogen peroxide-sensitive protein Hyper. Electrical stimulation (ES) triggered a transient ROS increase in muscle fibers which was mimicked by extracellular ATP and was prevented by both carbenoxolone and suramin; antagonists of pannexin channel and purinergic receptors respectively. In addition, transient ROS increase was prevented by apyrase, an ecto-nucleotidase. MRS2365, a P2Y1 receptor agonist, induced a large signal while UTPyS (P2Y2 agonist) elicited a much smaller signal, similar to the one seen when using ATP plus MRS2179, an antagonist of P2Y1. Protein kinase C (PKC) inhibitors also blocked ES-induced ROS production. Our results indicate that physiological levels of electrical stimulation induce ROS production in skeletal muscle cells through release of extracellular ATP and activation of P2Y1 receptors. Use of selective NOX2 and PKC inhibitors suggests that ROS production induced by ES or extracellular ATP is mediated by NOX2 activated by PKC. PMID:26053483

  13. ROS Production via P2Y1-PKC-NOX2 Is Triggered by Extracellular ATP after Electrical Stimulation of Skeletal Muscle Cells.

    PubMed

    Díaz-Vegas, Alexis; Campos, Cristian A; Contreras-Ferrat, Ariel; Casas, Mariana; Buvinic, Sonja; Jaimovich, Enrique; Espinosa, Alejandra

    2015-01-01

    During exercise, skeletal muscle produces reactive oxygen species (ROS) via NADPH oxidase (NOX2) while inducing cellular adaptations associated with contractile activity. The signals involved in this mechanism are still a matter of study. ATP is released from skeletal muscle during electrical stimulation and can autocrinely signal through purinergic receptors; we searched for an influence of this signal in ROS production. The aim of this work was to characterize ROS production induced by electrical stimulation and extracellular ATP. ROS production was measured using two alternative probes; chloromethyl-2,7- dichlorodihydrofluorescein diacetate or electroporation to express the hydrogen peroxide-sensitive protein Hyper. Electrical stimulation (ES) triggered a transient ROS increase in muscle fibers which was mimicked by extracellular ATP and was prevented by both carbenoxolone and suramin; antagonists of pannexin channel and purinergic receptors respectively. In addition, transient ROS increase was prevented by apyrase, an ecto-nucleotidase. MRS2365, a P2Y1 receptor agonist, induced a large signal while UTPyS (P2Y2 agonist) elicited a much smaller signal, similar to the one seen when using ATP plus MRS2179, an antagonist of P2Y1. Protein kinase C (PKC) inhibitors also blocked ES-induced ROS production. Our results indicate that physiological levels of electrical stimulation induce ROS production in skeletal muscle cells through release of extracellular ATP and activation of P2Y1 receptors. Use of selective NOX2 and PKC inhibitors suggests that ROS production induced by ES or extracellular ATP is mediated by NOX2 activated by PKC.

  14. A Murine Model of Muscle Training by Neuromuscular Electrical Stimulation

    PubMed Central

    Ambrosio, Fabrisia; Fitzgerald, G. Kelley; Ferrari, Ricardo; Distefano, Giovanna; Carvell, George

    2012-01-01

    Neuromuscular electrical stimulation (NMES) is a common clinical modality that is widely used to restore1, maintain2 or enhance3-5 muscle functional capacity. Transcutaneous surface stimulation of skeletal muscle involves a current flow between a cathode and an anode, thereby inducing excitement of the motor unit and the surrounding muscle fibers. NMES is an attractive modality to evaluate skeletal muscle adaptive responses for several reasons. First, it provides a reproducible experimental model in which physiological adaptations, such as myofiber hypertophy and muscle strengthening6, angiogenesis7-9, growth factor secretion9-11, and muscle precursor cell activation12 are well documented. Such physiological responses may be carefully titrated using different parameters of stimulation (for Cochrane review, see 13). In addition, NMES recruits motor units non-selectively, and in a spatially fixed and temporally synchronous manner14, offering the advantage of exerting a treatment effect on all fibers, regardless of fiber type. Although there are specified contraindications to NMES in clinical populations, including peripheral venous disorders or malignancy, for example, NMES is safe and feasible, even for those who are ill and/or bedridden and for populations in which rigorous exercise may be challenging. Here, we demonstrate the protocol for adapting commercially available electrodes and performing a NMES protocol using a murine model. This animal model has the advantage of utilizing a clinically available device and providing instant feedback regarding positioning of the electrode to elicit the desired muscle contractile effect. For the purpose of this manuscript, we will describe the protocol for muscle stimulation of the anterior compartment muscles of a mouse hindlimb. PMID:22617846

  15. A murine model of muscle training by neuromuscular electrical stimulation.

    PubMed

    Ambrosio, Fabrisia; Fitzgerald, G Kelley; Ferrari, Ricardo; Distefano, Giovanna; Carvell, George

    2012-05-09

    Neuromuscular electrical stimulation (NMES) is a common clinical modality that is widely used to restore (1), maintain (2) or enhance (3-5) muscle functional capacity. Transcutaneous surface stimulation of skeletal muscle involves a current flow between a cathode and an anode, thereby inducing excitement of the motor unit and the surrounding muscle fibers. NMES is an attractive modality to evaluate skeletal muscle adaptive responses for several reasons. First, it provides a reproducible experimental model in which physiological adaptations, such as myofiber hypertophy and muscle strengthening (6), angiogenesis (7-9), growth factor secretion (9-11), and muscle precursor cell activation (12) are well documented. Such physiological responses may be carefully titrated using different parameters of stimulation (for Cochrane review, see (13)). In addition, NMES recruits motor units non-selectively, and in a spatially fixed and temporally synchronous manner (14), offering the advantage of exerting a treatment effect on all fibers, regardless of fiber type. Although there are specified contraindications to NMES in clinical populations, including peripheral venous disorders or malignancy, for example, NMES is safe and feasible, even for those who are ill and/or bedridden and for populations in which rigorous exercise may be challenging. Here, we demonstrate the protocol for adapting commercially available electrodes and performing a NMES protocol using a murine model. This animal model has the advantage of utilizing a clinically available device and providing instant feedback regarding positioning of the electrode to elicit the desired muscle contractile effect. For the purpose of this manuscript, we will describe the protocol for muscle stimulation of the anterior compartment muscles of a mouse hindlimb.

  16. A diacylglycerol kinase inhibitor, R59022, stimulates glucose transport through a MKK3/6-p38 signaling pathway in skeletal muscle cells.

    PubMed

    Takahashi, Nobuhiko; Nagamine, Miho; Tanno, Satoshi; Motomura, Wataru; Kohgo, Yutaka; Okumura, Toshikatsu

    2007-08-17

    Diacylglycerol kinase (DGK) is one of lipid-regulating enzymes, catalyzes phosphorylation of diacylglycerol to phosphatidic acid. Because skeletal muscle, a major insulin-target organ for glucose disposal, expresses DGK, we investigated in the present study a role of DGK on glucose transport in skeletal muscle cells. PCR study showed that C2C12 myotubes expressed DGKalpha, delta, epsilon, zeta, or theta isoform mRNA. R59022, a specific inhibitor of DGK, significantly increased glucose transport, p38 and MKK3/6 activation in C2C12 myotubes. The R59022-induced glucose transport was blocked by SB203580, a specific p38 inhibitor. In contrast, R59022 failed to stimulate both possible known mechanisms to enhance glucose transport, an IRS1-PI3K-Akt pathway, muscle contraction signaling or GLUT1 and 4 expression. All these results suggest that DGK may play a role in glucose transport in the skeletal muscle cells through modulating a MKK3/6-p38 signaling pathway.

  17. Hypoxia stimulates the autocrine regulation of migration of vascular smooth muscle cells via HIF-1alpha-dependent expression of thrombospondin-1.

    PubMed

    Osada-Oka, Mayuko; Ikeda, Takako; Akiba, Satoshi; Sato, Takashi

    2008-08-01

    The migration of vascular smooth muscle cells from the media to intima and their subsequent proliferation are critical causes of arterial wall thickening. In atherosclerotic lesions increases in the thickness of the vascular wall and the impairment of oxygen diffusion capacity result in the development of hypoxic lesions. We investigated the effect of hypoxia on the migration of human coronary artery smooth muscle cells (CASMCs) via HIF-1alpha-dependent expression of thrombospondin-1 (TSP-1). When the cells were cultured under hypoxic conditions, mRNA and protein levels of TSP-1, and mRNA levels of integrin beta(3) were increased with the increase in HIF-1alpha protein. DNA synthesis and migration of the cells were stimulated under the conditions, and a neutralizing anti-TSP-1 antibody apparently suppressed the migration, but not DNA synthesis. The migration was also inhibited by RGD peptide that binds to integrin beta(3). Furthermore, the migration was completely suppressed in HIF-1alpha-knockdown cells exposed to hypoxia, while it was significantly enhanced in HIF-1alpha-overexpressing cells. These results suggest that the hypoxia induces the migration of CASMCs, and that the migration is elicited by TSP-1 of which induction is fully dependent on the stabilization of HIF-1alpha, in autocrine regulation. Thus we suggest that HIF-1alpha plays an important role in the pathogenesis of atherosclerosis.

  18. Carnosic acid stimulates glucose uptake in skeletal muscle cells via a PME-1/PP2A/PKB signalling axis.

    PubMed

    Lipina, Christopher; Hundal, Harinder S

    2014-11-01

    Carnosic acid (CA) is a major constituent of the labiate herbal plant Rosemary (Rosmarinus officinalis), which has been shown to exhibit a number of beneficial health properties. In particular, recently there has been growing interest into the anti-obesity effects conveyed by CA, including its ability to counteract obesity-associated hyperglycaemia and insulin resistance. However, the mechanisms underlying its anti-diabetic responses are not fully understood. In this study, we hypothesized that CA may act to improve glycaemic status through enhancing peripheral glucose clearance. Herein, we demonstrate that CA acts to mimic the metabolic actions of insulin by directly stimulating glucose uptake in rat skeletal L6 myotubes, concomitant with increased translocation of the GLUT4 glucose transporter to the plasma membrane. Mechanistically, CA-induced glucose transport was found to be dependent on protein kinase B (PKB/Akt) but not AMPK, despite both kinases being activated by CA. Crucially, in accordance with its ability to activate PKB and stimulate glucose uptake, we show that CA conveys these effects through a pathway involving PME-1 (protein phosphatase methylesterase-1), a key negative regulator of the serine/threonine phosphatase PP2A (protein phosphatase 2A). Herein, we demonstrate that CA promotes PME-1 mediated demethylation of the PP2A catalytic subunit leading to its suppressed activity, and in doing so, alleviates the repressive action of PP2A towards PKB. Collectively, our findings provide new insight into how CA may improve glucose homeostasis through enhancing peripheral glucose clearance in tissues such as skeletal muscle through a PME-1/PP2A/PKB signalling axis, thereby mitigating pathological effects associated with the hyperglycaemic state.

  19. Transcranial magnetic stimulation and human muscle fatigue.

    PubMed

    Taylor, J L; Gandevia, S C

    2001-01-01

    During exercise, changes occur at many sites in the motor pathway, including the muscle fiber, motoneuron, motor cortex, and "upstream" of the motor cortex. Some of the changes result in fatigue, which can be defined as a decrease in ability to produce maximal muscle force voluntarily. Transcranial magnetic stimulation (TMS) over the human motor cortex reveals changes in both motor evoked potentials (MEPs) and the silent period during and after fatiguing voluntary contractions in normal subjects. The relationship of these changes to loss of force or fatigue is unclear. However, during a sustained maximal contraction TMS evokes extra force from the muscle and thus demonstrates the development of suboptimal output from the motor cortex, that is, fatigue at a supraspinal level. In some patients with symptoms of fatigue, the response to TMS after exercise is altered, but the changed MEP behavior is not yet linked to particular symptoms or pathology.

  20. Arginase inhibition reduces interleukin-1β-stimulated vascular smooth muscle cell proliferation by increasing nitric oxide synthase-dependent nitric oxide production

    SciTech Connect

    Yoon, Jeongyeon; Ryoo, Sungwoo

    2013-06-07

    Highlights: •Arginase inhibition suppressed proliferation of IL-1β-stimulated VSMCs in dose-dependent manner. •NO production from IL-1β-induced iNOS expression was augmented by arginase inhibition, reducing VSMC proliferation. •Incubation with cGMP analogues abolished IL-1β-dependent proliferation of VSMCs. -- Abstract: We investigated whether arginase inhibition suppressed interleukin (IL)-1β-stimulated proliferation in vascular smooth muscle cells (VSMCs) and the possible mechanisms involved. IL-1β stimulation increased VSMC proliferation, while the arginase inhibitor BEC and transfection of the antisense (AS) oligonucleotide against arginase I decreased VSMC proliferation and was associated with increased protein content of the cell cycle regulator p21Waf1/Cip1. IL-1β incubation induced inducible nitric oxide synthase (iNOS) mRNA expression and protein levels in a dose-dependent manner, but did not affect arginase I and II expression. Consistent with this data, IL-1β stimulation resulted in increase in NO production that was significantly augmented by arginase inhibition. The specific iNOS inhibitor 1400W abolished IL-1β-mediated NO production and further accentuated IL-1β-stimulated cell proliferation. Incubation with NO donors GSNO and DETA/NO in the presence of IL-1β abolished VSMCs proliferation and increased p21Waf1/Cip1 protein content. Furthermore, incubation with the cGMP analogue 8-Br-cGMP prevented IL-1β-induced VSMCs proliferation. In conclusion, arginase inhibition augmented iNOS-dependent NO production that resulted in suppression of IL-1β-induced VSMCs proliferation in a cGMP-dependent manner.

  1. Relationship of MTT reduction to stimulants of muscle metabolism.

    PubMed

    Newman, J M; DiMaria, C A; Rattigan, S; Steen, J T; Miller, K A; Eldershaw, T P; Clark, M G

    2000-10-16

    MTT, a positively charged tetrazolium salt, is widely used as an indicator of cell viability and metabolism and has potential for histochemical identification of tissue regions of hypermetabolism. In the present study, MTT was infused in the constant-flow perfused rat hindlimb to assess the effect of various agents and particularly vasoconstrictors that increase muscle metabolism. Reduction of MTT to the insoluble formazan in muscles assessed at the end of experiments was linear over a 30 min period and production rates were greater in red fibre types than white fibre types. The vasoconstrictors, norepinephrine (100 nM) and angiotensin (10 nM) decreased MTT formazan production in all muscles but increased hindlimb oxygen uptake and lactate efflux. Veratridine, a Na(+) channel opener that increases hindlimb oxygen uptake and lactate efflux without increases in perfusion pressure, also decreased MTT formazan production. Membrane stabilizing doses (100 microM) of (+/-)-propranolol reversed the inhibitory effects of angiotensin and veratridine on MTT formazan production. Muscle contractions elicited by stimulation of the sciatic nerve, reversed the norepinephrine-mediated inhibitory effects on MTT formazan production, even though oxygen consumption and lactate efflux were further stimulated. Stimulation of hindlimb muscle oxygen uptake by pentachlorophenol, a mitochondrial uncoupler, was not associated with alterations in MTT formazan production. It is concluded that apart from muscle contractions MTT formazan production does not increase with increased muscle metabolism. Since the vasoconstrictors angiotensin and norepinephrine as well as veratridine activate Na(+) channels and the Na(+)/K(+) pump, energy required for Na(+) pumping may be required for MTT reduction. It is unlikely that vasoconstrictors that stimulate oxygen uptake do so by uncoupling respiration.

  2. Stimulation with monochromatic green light during incubation alters satellite cell mitotic activity and gene expression in relation to embryonic and posthatch muscle growth of broiler chickens.

    PubMed

    Zhang, L; Zhang, H J; Wang, J; Wu, S G; Qiao, X; Yue, H Y; Yao, J H; Qi, G H

    2014-01-01

    Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight (BW) and pectoral muscle growth of broilers. In this experiment, we further investigated the morphological and molecular basis of this phenomenon. Fertile broiler eggs (Arbor Acres, n=880) were pre-weighed and randomly assigned to 1 of the 2 incubation treatment groups: (1) dark condition (control group), and (2) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. The dark condition was set as a commercial control from day 1 until hatching. After hatch, 120 male 1-day-old chicks from each group were housed under incandescent white light with an intensity of 30 lx at bird-head level. No effects of light stimuli during embryogenesis on hatching time, hatchability, hatching weight and bird mortality during the feeding trial period were observed in the present study. Compared with the dark condition, the BW, pectoral muscle weight and myofiber cross-sectional areas were significantly greater on 7-day-old chicks incubated under green light. Green light also increased the satellite cell mitotic activity of pectoral muscle on 1- and 3-day-old birds. In addition, green light upregulated MyoD, myogenin and myostatin mRNA expression in late embryos and/ or newly hatched chicks. These data suggest that stimulation with monochromatic green light during incubation promote muscle growth by enhancing proliferation and differentiation of satellite cells in late embryonic and newly hatched stages. Higher expression of myostatin may ultimately help prevent excessive proliferation and differentiation of satellite cells in birds incubated under green light.

  3. c-Ski inhibits the proliferation of vascular smooth muscle cells via suppressing Smad3 signaling but stimulating p38 pathway.

    PubMed

    Li, Jun; Li, Ping; Zhang, Yan; Li, Gong-Bo; Zhou, Yuan-Guo; Yang, Kang; Dai, Shuang-Shuang

    2013-01-01

    Proliferation of vascular smooth muscle cells (VSMCs) plays key roles in the progression of intimal hyperplasia, but the molecular mechanisms that trigger VSMC proliferation after vascular injury remain unclear. c-Ski, a co-repressor of transforming growth factor β (TGF-β)/Smad signaling, was detected to express in VSMC of rat artery. During the course of arterial VSMC proliferation induced by balloon injury in rat, the endogenous protein expressions of c-Ski decreased markedly in a time-dependent manner. In vivo c-Ski gene delivery was found to significantly suppress balloon injury-induced VSMC proliferation and neointima formation. Further investigation in A10 rat aortic smooth muscle cells demonstrated that overexpression of c-Ski gene inhibited TGF-β1 (1 ng/ml)-induced A10 cell proliferation while knockdown of c-Ski by RNAi enhanced the stimulatory effect of TGF-β1 on A10 cell growth. Western blot for signaling detection showed that suppression of Smad3 phosphorylation while stimulating p38 signaling associated with upregulation of cyclin-dependent kinase inhibitors p21 and p27 was responsible for the inhibitory effect of c-Ski on TGF-β1-induced VSMC proliferation. These data suggest that the decrease of endogenous c-Ski expression is implicated in the progression of VSMC proliferation after arterial injury and c-Ski administration represents a promising role for treating intimal hyperplasia via inhibiting the proliferation of VSMC.

  4. TNAP stimulates vascular smooth muscle cell trans-differentiation into chondrocytes through calcium deposition and BMP-2 activation: Possible implication in atherosclerotic plaque stability.

    PubMed

    Fakhry, Maya; Roszkowska, Monika; Briolay, Anne; Bougault, Carole; Guignandon, Alain; Diaz-Hernandez, Juan Ignacio; Diaz-Hernandez, Miguel; Pikula, Slawomir; Buchet, René; Hamade, Eva; Badran, Bassam; Bessueille, Laurence; Magne, David

    2017-03-01

    Atherosclerotic plaque calcification varies from early, diffuse microcalcifications to a bone-like tissue formed by endochondral ossification. Recently, a paradigm has emerged suggesting that if the bone metaplasia stabilizes the plaques, microcalcifications are harmful. Tissue-nonspecific alkaline phosphatase (TNAP), an ectoenzyme necessary for mineralization by its ability to hydrolyze inorganic pyrophosphate (PPi), is stimulated by inflammation in vascular smooth muscle cells (VSMCs). Our objective was to determine the role of TNAP in trans-differentiation of VSMCs and calcification. In rodent MOVAS and A7R5 VSMCs, addition of exogenous alkaline phosphatase (AP) or TNAP overexpression was sufficient to stimulate the expression of several chondrocyte markers and induce mineralization. Addition of exogenous AP to human mesenchymal stem cells cultured in pellets also stimulated chondrogenesis. Moreover, TNAP inhibition with levamisole in mouse primary chondrocytes dropped mineralization as well as the expression of chondrocyte markers. VSMCs trans-differentiated into chondrocyte-like cells, as well as primary chondrocytes, used TNAP to hydrolyze PPi, and PPi provoked the same effects as TNAP inhibition in primary chondrocytes. Interestingly, apatite crystals, associated or not to collagen, mimicked the effects of TNAP on VSMC trans-differentiation. AP and apatite crystals increased the expression of BMP-2 in VSMCs, and TNAP inhibition reduced BMP-2 levels in chondrocytes. Finally, the BMP-2 inhibitor noggin blocked the rise in aggrecan induced by AP in VSMCs, suggesting that TNAP induction in VSMCs triggers calcification, which stimulates chondrogenesis through BMP-2. Endochondral ossification in atherosclerotic plaques may therefore be induced by crystals, probably to confer stability to plaques with microcalcifications.

  5. Mapping of electrical muscle stimulation using MRI

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.; Harris, Robert T.; Woodard, Daniel; Dudley, Gary A.

    1993-01-01

    The pattern of muscle contractile activity elicited by electromyostimulation (EMS) was mapped and compared to the contractile-activity pattern produced by voluntary effort. This was done by examining the patterns and the extent of contrast shift, as indicated by T2 values, im magnetic resonance (MR) images after isometric activity of the left m. quadriceps of human subjects was elicited by EMS (1-sec train of 500-microsec sine wave pulses at 50 Hz) or voluntary effort. The results suggest that, whereas EMS stimulates the same fibers repeatedly, thereby increasing the metabolic demand and T2 values, the voluntary efforts are performed by more diffuse asynchronous activation of skeletal muscle even at forces up to 75 percent of maximal to maintain performance.

  6. Airway epithelium stimulates smooth muscle proliferation.

    PubMed

    Malavia, Nikita K; Raub, Christopher B; Mahon, Sari B; Brenner, Matthew; Panettieri, Reynold A; George, Steven C

    2009-09-01

    Communication between the airway epithelium and stroma is evident during embryogenesis, and both epithelial shedding and increased smooth muscle proliferation are features of airway remodeling. Hence, we hypothesized that after injury the airway epithelium could modulate airway smooth muscle proliferation. Fully differentiated primary normal human bronchial epithelial (NHBE) cells at an air-liquid interface were co-cultured with serum-deprived normal primary human airway smooth muscle cells (HASM) using commercially available Transwells. In some co-cultures, the NHBE were repeatedly (x4) scrape-injured. An in vivo model of tracheal injury consisted of gently denuding the tracheal epithelium (x3) of a rabbit over 5 days and then examining the trachea by histology 3 days after the last injury. Our results show that HASM cell number increases 2.5-fold in the presence of NHBE, and 4.3-fold in the presence of injured NHBE compared with HASM alone after 8 days of in vitro co-culture. In addition, IL-6, IL-8, monocyte chemotactic protein (MCP)-1 and, more markedly, matrix metalloproteinase (MMP)-9 concentration increased in co-culture correlating with enhanced HASM growth. Inhibiting MMP-9 release significantly attenuated the NHBE-dependent HASM proliferation in co-culture. In vivo, the injured rabbit trachea demonstrated proliferation in the smooth muscle (trachealis) region and significant MMP-9 staining, which was absent in the uninjured control. The airway epithelium modulates smooth muscle cell proliferation via a mechanism that involves secretion of soluble mediators including potential smooth muscle mitogens such as IL-6, IL-8, and MCP-1, but also through a novel MMP-9-dependent mechanism.

  7. RhoA Phosphorylation Induces Rac1 Release from Guanine Dissociation Inhibitor α and Stimulation of Vascular Smooth Muscle Cell Migration▿

    PubMed Central

    Rolli-Derkinderen, Malvyne; Toumaniantz, Gilles; Pacaud, Pierre; Loirand, Gervaise

    2010-01-01

    Although overactivation of RhoA is recognized as a common component of vascular disorders, the molecular mechanisms regulating RhoA activity in vascular smooth muscle cells (VSMC) are still unclear. We have previously shown that in VSMC, RhoA is phosphorylated on Ser188 by nitric oxide (NO)-stimulated cGMP-dependent kinase (PKG), which leads to RhoA-Rho kinase pathway inhibition. In this study, we showed that expression of phosphoresistant RhoA mutants prevented the stimulation of VSMC migration and adhesion induced by NO-PKG pathway activation. In contrast, under basal conditions, phosphomimetic RhoA mutants stimulated VSMC adhesion and migration through a signaling pathway requiring Rac1 and the Rho exchange factor Vav3. RhoA phosphorylation or phosphomimetic RhoA mutants induced Rac1 activation but did not activate Vav3. Indeed, phosphorylated RhoA or phosphomimetic mutants trapped guanine dissociation inhibitor α (GDIα), leading to the release of Rac1 and its translocation to the membrane, where it was then activated by the basal Vav3 nucleotide exchange activity. In vivo, RhoA phosphorylation induced by PKG activation in the aortas of rats treated with sildenafil induced dissociation of Rac1 from GDIα and activation of the Rac1 signaling pathway. These results suggest that the phosphorylation of RhoA represents a novel potent and physiological GDIα displacement factor that leads to Rac1 activation and regulation of Rac1-dependent VSMC functions. PMID:20696841

  8. Fibroblast growth factor stimulates angiotensin converting enzyme expression in vascular smooth muscle cells. Possible mediator of the response to vascular injury.

    PubMed Central

    Fishel, R S; Thourani, V; Eisenberg, S J; Shai, S Y; Corson, M A; Nabel, E G; Bernstein, K E; Berk, B C

    1995-01-01

    Angiotensin converting enzyme (ACE) activity contributes to the vascular response to injury because ACE inhibition limits neointima formation in rat carotid arteries after balloon injury. To investigate the mechanisms by which ACE may contribute to vascular smooth muscle cell (VSMC) proliferation, we studied expression of ACE in vivo after injury and in vitro after growth factor stimulation. ACE activity 14 d after injury was increased 3.6-fold in the injured vessel. ACE expression, measured by immunohistochemistry, became apparent at 7 d in the neointima and at 14 d was primarily in the most luminal neointimal cells. To characterize hormones that induce ACE in vivo, cultured VSMC were exposed to steroids and growth factors. Among steroids, only glucocorticoids stimulated ACE expression with an 8.0 +/- 2.1-fold increase in activity and a 6.5-fold increase in mRNA (30 nM dexamethasone for 72 h). Among growth factors tested, only fibroblast growth factor (FGF) stimulated ACE expression (4.2 +/- 0.7-fold increase in activity and 1.6-fold increase in mRNA in response to 10 ng/ml FGF for 24 h). Dexamethasone and FGF were synergistic at the indicated concentrations inducing 50.6 +/- 12.4-fold and 32.5-fold increases in activity and mRNA expression, respectively. In addition, when porcine iliac arteries were transfected with recombinant FGF-1 (in the absence of injury), ACE expression increased in neointimal VSMC, to the same extent as injured, nontransfected arteries. The data suggest a temporal sequence for the response to injury in which FGF induces ACE, ACE generates angiotensin II, and angiotensin II stimulates VSMC growth in concert with FGF. Images PMID:7814638

  9. Stimulant actions of volatile anaesthetics on smooth muscle

    PubMed Central

    Rang, H. P.

    1964-01-01

    A number of volatile anaesthetics, and some compounds synthesized in the search for new anaesthetics, have been tested on guinea-pig intestinal smooth muscle in vitro. All the compounds produced a contractile response. This effect did not correlate well with convulsant activity in vivo among the compounds tested. Two kinds of stimulant effect were distinguishable: (1) Rapid, transient contractions, abolished by cocaine or lachesine; most of the anaesthetics in clinical use had this action. (2) Slow, sustained contractions, unaffected by cocaine or lachesine; this effect predominated among the fluorinated ring compounds. Hexamethonium and mepyramine did not affect the contractile response to any of the compounds. The first type of effect presumably represents excitation of postganglionic nerve cells, while the second type is a direct action on the muscle cell. The action of perfluorobenzene, which is of the latter kind, was studied further. Adrenaline and lack of calcium diminished the contraction in parallel with the contraction to histamine, which suggests that the cell membrane was the site of action; in contrast to the stimulant action of histamine or acetylcholine, the effect was highly temperature-sensitive, being almost abolished by cooling to 32° C, and enhanced at 40° C. The depressant action of anaesthetics on smooth muscle is affected very little by temperature changes. These findings are discussed in relation to other observations which suggest a stimulant action of volatile anaesthetics on excitable tissues. Protein denaturation is tentatively suggested as a mechanism of action. PMID:14190470

  10. Mechanical stimulation improves tissue-engineered human skeletal muscle.

    PubMed

    Powell, Courtney A; Smiley, Beth L; Mills, John; Vandenburgh, Herman H

    2002-11-01

    Human bioartificial muscles (HBAMs) are tissue engineered by suspending muscle cells in collagen/MATRIGEL, casting in a silicone mold containing end attachment sites, and allowing the cells to differentiate for 8 to 16 days. The resulting HBAMs are representative of skeletal muscle in that they contain parallel arrays of postmitotic myofibers; however, they differ in many other morphological characteristics. To engineer improved HBAMs, i.e., more in vivo-like, we developed Mechanical Cell Stimulator (MCS) hardware to apply in vivo-like forces directly to the engineered tissue. A sensitive force transducer attached to the HBAM measured real-time, internally generated, as well as externally applied, forces. The muscle cells generated increasing internal forces during formation which were inhibitable with a cytoskeleton depolymerizer. Repetitive stretch/relaxation for 8 days increased the HBAM elasticity two- to threefold, mean myofiber diameter 12%, and myofiber area percent 40%. This system allows engineering of improved skeletal muscle analogs as well as a nondestructive method to determine passive force and viscoelastic properties of the resulting tissue.

  11. Mechanical stimulation improves tissue-engineered human skeletal muscle

    NASA Technical Reports Server (NTRS)

    Powell, Courtney A.; Smiley, Beth L.; Mills, John; Vandenburgh, Herman H.

    2002-01-01

    Human bioartificial muscles (HBAMs) are tissue engineered by suspending muscle cells in collagen/MATRIGEL, casting in a silicone mold containing end attachment sites, and allowing the cells to differentiate for 8 to 16 days. The resulting HBAMs are representative of skeletal muscle in that they contain parallel arrays of postmitotic myofibers; however, they differ in many other morphological characteristics. To engineer improved HBAMs, i.e., more in vivo-like, we developed Mechanical Cell Stimulator (MCS) hardware to apply in vivo-like forces directly to the engineered tissue. A sensitive force transducer attached to the HBAM measured real-time, internally generated, as well as externally applied, forces. The muscle cells generated increasing internal forces during formation which were inhibitable with a cytoskeleton depolymerizer. Repetitive stretch/relaxation for 8 days increased the HBAM elasticity two- to threefold, mean myofiber diameter 12%, and myofiber area percent 40%. This system allows engineering of improved skeletal muscle analogs as well as a nondestructive method to determine passive force and viscoelastic properties of the resulting tissue.

  12. Multiple stimulations for muscle-nerve-blood vessel unit in compensatory hypertrophied skeletal muscle of rat surgical ablation model.

    PubMed

    Tamaki, Tetsuro; Uchiyama, Yoshiyasu; Okada, Yoshinori; Tono, Kayoko; Nitta, Masahiro; Hoshi, Akio; Akatsuka, Akira

    2009-07-01

    Tissue inflammation and multiple cellular responses in the compensatory enlarged plantaris (OP Plt) muscle induced by surgical ablation of synergistic muscles (soleus and gastrocnemius) were followed over 10 weeks after surgery. Contralateral surgery was performed in adult Wistar male rats. Cellular responses in muscle fibers, blood vessels and nerve fibers were analyzed by immunohistochemistry and electron microscopy. Severe muscle fiber damage and disappearance of capillaries associated with apparent tissue edema were observed in the peripheral portion of OP Plt muscles during the first week, whereas central portions were relatively preserved. Marked cell activation/proliferation was also mainly observed in peripheral portions. Similarly, activated myogenic cells were seen not only inside but also outside of muscle fibers. The former were likely satellite cells and the latter may be interstitial myogenic cells. One week after surgery, small muscle fibers, small arteries and capillaries and several branched-muscle fibers were evident in the periphery, thus indicating new muscle fiber and blood vessel formation. Proliferating cells were also detected in the nerve bundles in the Schwann cell position. These results indicate that the compensatory stimulated/enlarged muscle is a suitable model for analyzing multiple physiological cellular responses in muscle-nerve-blood vessel units under continuous stretch stimulation.

  13. Smooth muscle cell-specific Tgfbr1 deficiency promotes aortic aneurysm formation by stimulating multiple signaling events

    PubMed Central

    Yang, Pu; Schmit, Bradley M.; Fu, Chunhua; DeSart, Kenneth; Oh, S. Paul; Berceli, Scott A.; Jiang, Zhihua

    2016-01-01

    Transforming growth factor (TGF)-β signaling disorder has emerged as a common molecular signature for aortic aneurysm development. The timing of postnatal maturation plays a key role in dictating the biological outcome of TGF-β signaling disorders in the aortic wall. In this study, we investigated the impact of deficiency of TGFβ receptors on the structural homeostasis of mature aortas. We used an inducible Cre-loxP system driven by a Myh11 promoter to delete Tgfbr1, Tgfbr2, or both in smooth muscle cells (SMCs) of adult mice. TGFBR1 deficiency resulted in rapid and severe aneurysmal degeneration, with 100% penetrance of ascending thoracic aortas, whereas TGFBR2 deletion only caused mild aortic pathology with low (26%) lesion prevalence. Removal of TGFBR2 attenuated the aortic pathology caused by TGFBR1 deletion and correlated with a reduction of early ERK phosphorylation. In addition, the production of angiotensin (Ang)-converting enzyme was upregulated in TGFBR1 deficient aortas at the early stage of aneurysmal degeneration. Inhibition of ERK phosphorylation or blockade of AngII type I receptor AT1R prevented aneurysmal degeneration of TGFBR1 deficient aortas. In conclusion, loss of SMC-Tgfbr1 triggers multiple deleterious pathways, including abnormal TGFBR2, ERK, and AngII/AT1R signals that disrupt aortic wall homeostasis to cause aortic aneurysm formation. PMID:27739498

  14. Muscle fiber type specific induction of slow myosin heavy chain 2 gene expression by electrical stimulation

    SciTech Connect

    Crew, Jennifer R.; Falzari, Kanakeshwari; DiMario, Joseph X.

    2010-04-01

    Vertebrate skeletal muscle fiber types are defined by a broad array of differentially expressed contractile and metabolic protein genes. The mechanisms that establish and maintain these different fiber types vary throughout development and with changing functional demand. Chicken skeletal muscle fibers can be generally categorized as fast and fast/slow based on expression of the slow myosin heavy chain 2 (MyHC2) gene in fast/slow muscle fibers. To investigate the cellular and molecular mechanisms that control fiber type formation in secondary or fetal muscle fibers, myoblasts from the fast pectoralis major (PM) and fast/slow medial adductor (MA) muscles were isolated, allowed to differentiate in vitro, and electrically stimulated. MA muscle fibers were induced to express the slow MyHC2 gene by electrical stimulation, whereas PM muscle fibers did not express the slow MyHC2 gene under identical stimulation conditions. However, PM muscle fibers did express the slow MyHC2 gene when electrical stimulation was combined with inhibition of inositol triphosphate receptor (IP3R) activity. Electrical stimulation was sufficient to increase nuclear localization of expressed nuclear-factor-of-activated-T-cells (NFAT), NFAT-mediated transcription, and slow MyHC2 promoter activity in MA muscle fibers. In contrast, both electrical stimulation and inhibitors of IP3R activity were required for these effects in PM muscle fibers. Electrical stimulation also increased levels of peroxisome-proliferator-activated receptor-{gamma} co-activator-1 (PGC-1{alpha}) protein in PM and MA muscle fibers. These results indicate that MA muscle fibers can be induced by electrical stimulation to express the slow MyHC2 gene and that fast PM muscle fibers are refractory to stimulation-induced slow MyHC2 gene expression due to fast PM muscle fiber specific cellular mechanisms involving IP3R activity.

  15. Oxidatively modified LDL contains phospholipids with platelet-activating factor-like activity and stimulates the growth of smooth muscle cells.

    PubMed Central

    Heery, J M; Kozak, M; Stafforini, D M; Jones, D A; Zimmerman, G A; McIntyre, T M; Prescott, S M

    1995-01-01

    Oxidative modification of lipoproteins is believed to be important in the genesis of atherosclerosis. We established cultures of smooth muscle cells (SMC) and exposed them to native LDL or oxidized LDL. Oxidized LDL, but not native LDL, was mitogenic as measured by incorporation of [3H]-thymidine into DNA. This effect was concentration dependent, averaged 288% of control, and was blocked by a platelet-activating factor (PAF) receptor antagonist. We hypothesized that phospholipids with PAF-like activity were generated during the oxidation of LDL. To test this hypothesis we extracted phospholipids from copper-oxidized LDL and assayed for PAF-like activity. Phospholipids extracted from oxidized LDL and purified by HPLC induced neutrophil adhesion equivalent to PAF (10 nM) and were mitogenic for smooth muscle cells. These effects were not seen with phospholipids extracted from native LDL and were blocked by two structurally different, competitive antagonists of the PAF receptor. The effects of these lipids were also abolished by pretreating them with PAF acetylhydrolase. Finally, we used Chinese hamster ovary cells that had seen stably transfected with a cDNA for the PAF receptor to confirm that phospholipids from oxidized LDL act via this receptor. We found that PAF (control) and the oxidized phospholipids each induced release of arachidonic acid from the transfected cells, but had no effect on wildtype Chinese hamster ovary cells, which lack the PAF receptor. This effect was also blocked by a PAF receptor antagonist. Thus, phospholipids generated during oxidative modification of LDL may participate in atherosclerosis by stimulating SMC proliferation and leukocyte activation. Images PMID:7593619

  16. Store‐operated interactions between plasmalemmal STIM1 and TRPC1 proteins stimulate PLCβ1 to induce TRPC1 channel activation in vascular smooth muscle cells

    PubMed Central

    Shi, Jian; Miralles, Francesc; Birnbaumer, Lutz; Large, William A.

    2016-01-01

    Key points Depletion of Ca2+ stores activates store‐operated channels (SOCs), which mediate Ca2+ entry pathways that regulate cellular processes such as contraction, proliferation and gene expression.In vascular smooth muscle cells (VSMCs), stimulation of SOCs composed of canonical transient receptor potential channel 1 (TRPC1) proteins requires G protein α q subunit (Gαq)/phospholipase C (PLC)β1/protein kinase C (PKC) activity. We studied the role of stromal interaction molecule 1 (STIM1) in coupling store depletion to this activation pathway using patch clamp recording, GFP‐PLCδ1‐PH imaging and co‐localization techniques.Store‐operated TRPC1 channel and PLCβ1 activities were inhibited by STIM1 short hairpin RNA (shRNA) and absent in TRPC1−/− cells, and store‐operated PKC phosphorylation of TRPC1 was inhibited by STIM1 shRNA. Store depletion induced interactions between STIM1 and TRPC1, Gαq and PLCβ1, which required STIM1 and TRPC1. Similar effects were produced with noradrenaline.These findings identify a new activation mechanism of TRPC1‐based SOCs in VSMCs, and a novel role for STIM1, where store‐operated STIM1‐TRPC1 interactions stimulate Gαq/PLCβ1/PKC activity to induce channel gating. Abstract In vascular smooth muscle cells (VSMCs), stimulation of canonical transient receptor potential channel 1 (TRPC1) protein‐based store‐operated channels (SOCs) mediates Ca2+ entry pathways that regulate contractility, proliferation and migration. It is therefore important to understand how these channels are activated. Studies have shown that stimulation of TRPC1‐based SOCs requires G protein α q subunit (Gαq)/phospholipase C (PLC)β1 activities and protein kinase C (PKC) phosphorylation, although it is unclear how store depletion stimulates this gating pathway. The present study examines this issue by focusing on the role of stromal interaction molecule 1 (STIM1), an endo/sarcoplasmic reticulum Ca2+ sensor. Store‐operated TRPC1

  17. Coil Design for Functional Magnetic Stimulation of the Inspiratory Muscles

    DTIC Science & Technology

    2007-11-02

    Coil design for functional magnetic stimulation of the inspiratory muscles Ian N. Hsiao, Ph.D., member IEEE, Ercheng Zhu, MD, PhD, Vernon Lin...new magnetic coil (MC) for effective functional magnetic stimulation (FMS) of inspiratory muscles in human subjects. Part 1 of the study emphasized...2 is reported in another paper titled “Racetrack magnetic coil for functional magnetic stimulation of the inspiratory muscles – toward magnetic

  18. Altered ROS production, NF-κB activation and interleukin-6 gene expression induced by electrical stimulation in dystrophic mdx skeletal muscle cells.

    PubMed

    Henríquez-Olguín, Carlos; Altamirano, Francisco; Valladares, Denisse; López, José R; Allen, Paul D; Jaimovich, Enrique

    2015-07-01

    -κB activation and IL-6 expression. Exposure to lipopolysaccharide induced a dramatic increase in both NF-κB activation and IL-6 expression in both wt and mdx myotubes, suggesting that the altered IL-6 gene expression after electrical stimulation in mdx muscle cells is due to dysregulation of Ca2+ release and ROS production, both of which impinge on NF-κB signaling. IL-6 is a key metabolic modulator that is released by the skeletal muscle to coordinate a multi-systemic response (liver, muscle, and adipocytes) during physical exercise; the alteration of this response in dystrophic muscles may contribute to an abnormal response to contraction and exercise.

  19. Contraction stimulates muscle glucose uptake independent of atypical PKC.

    PubMed

    Yu, Haiyan; Fujii, Nobuharu L; Toyoda, Taro; An, Ding; Farese, Robert V; Leitges, Michael; Hirshman, Michael F; Mul, Joram D; Goodyear, Laurie J

    2015-11-01

    Exercise increases skeletal muscle glucose uptake, but the underlying mechanisms are only partially understood. The atypical protein kinase C (PKC) isoforms λ and ζ (PKC-λ/ζ) have been shown to be necessary for insulin-, AICAR-, and metformin-stimulated glucose uptake in skeletal muscle, but not for treadmill exercise-stimulated muscle glucose uptake. To investigate if PKC-λ/ζ activity is required for contraction-stimulated muscle glucose uptake, we used mice with tibialis anterior muscle-specific overexpression of an empty vector (WT), wild-type PKC-ζ (PKC-ζ(WT)), or an enzymatically inactive T410A-PKC-ζ mutant (PKC-ζ(T410A)). We also studied skeletal muscle-specific PKC-λ knockout (MλKO) mice. Basal glucose uptake was similar between WT, PKC-ζ(WT), and PKC-ζ(T410A) tibialis anterior muscles. In contrast, in situ contraction-stimulated glucose uptake was increased in PKC-ζ(T410A) tibialis anterior muscles compared to WT or PKC-ζ(WT) tibialis anterior muscles. Furthermore, in vitro contraction-stimulated glucose uptake was greater in soleus muscles of MλKO mice than WT controls. Thus, loss of PKC-λ/ζ activity increases contraction-stimulated muscle glucose uptake. These data clearly demonstrate that PKC-λζ activity is not necessary for contraction-stimulated glucose uptake.

  20. Insulin-like growth factor I and protein kinase C activation stimulate pulmonary artery smooth muscle cell proliferation through separate but synergistic pathways.

    PubMed

    Dempsey, E C; Stenmark, K R; McMurtry, I F; O'Brien, R F; Voelkel, N F; Badesch, D B

    1990-07-01

    Smooth muscle cell (SMC) hyperplasia is an important component of vascular remodeling in chronic hypoxic pulmonary hypertension. The mechanisms underlying SMC proliferation in the remodeling process are poorly understood, but may involve insulin-like growth factor I (IGF-I). This study investigates the potential proliferative effects of IGF-I on SMC cultured from the pulmonary arteries (PA) of neonatal calves. We hypothesized that IGF-I stimulates PA SMC proliferation through a protein kinase C (PKC)-independent pathway, but that PKC activation would augment this proliferative response. Incorporation of 3H-thymidine was used as an index of cellular proliferation, and was correlated with subsequent changes in cell counts. Under serum-free conditions, IGF-I (100 ng/ml) induced a 6-fold increase in thymidine incorporation by quiescent PA SMC. This stimulation was not blocked by dihydrosphingosine, an inhibitor of PKC activation. Phorbol myristate acetate (PMA) (1 nM), a membrane-permeable PKC activator, induced a 12-fold increase in thymidine incorporation which was 70% inhibited by dihydrosphingosine. Co-incubation with IGF-I and PMA caused a 60-fold increase in thymidine incorporation, which was 30% inhibited by dihydrosphingosine. This synergistic increase in thymidine incorporation was associated with a subsequent significant increase in cell number. PKC-downregulated cells (1,000 nM PMA x 30 hr) proliferated in response to IGF-I but not PMA, and did not demonstrate synergism with the combination of IGF-I and PMA. The threshold concentrations of IGF-I and PMA for synergism were approximately 1 ng/ml and 1 pM, respectively. We conclude that IGF-I stimulates neonatal PA SMC proliferation via a PKC-independent pathway, and that trace amounts of PKC activators are capable of synergistically augmenting this response. We speculate that the synergistic stimulation of SMC proliferation by IGF-I and PKC activators may play an important role in hypertensive pulmonary

  1. Biophysical Stimulation for Engineering Functional Skeletal Muscle.

    PubMed

    Somers, Sarah; Spector, Alexander; DiGirolamo, Douglas; Grayson, Warren L

    2017-04-12

    Tissue engineering is a promising therapeutic strategy to regenerate skeletal muscle. However, ex vivo cultivation methods typically result in a low differentiation efficiency of stem cells as well as grafts that resemble the native tissues morphologically, but lack contractile function. The application of biomimetic tensile strain provides a potent stimulus for enhancing myogenic differentiation and engineering functional skeletal muscle grafts. We reviewed integrin-dependent mechanisms that potentially link mechanotransduction pathways to the upregulation of myogenic genes. Yet, gaps in our understanding make it challenging to use these pathways to theoretically determine optimal ex vivo strain regimens. A multitude of strain protocols have been applied to in vitro cultures for the cultivation of myogenic progenitors (adipose- and bone marrow-derived stem cells & satellite cells) and transformed murine myoblasts, C2C12s. Strain regimen are characterized by orientation, amplitude, and time-dependent factors (effective frequency, duration, and the rest period between successive strain cycles). Analysis of published data has identified possible minimum/maximum values for these parameters and suggests that uniaxial strains may be more potent than biaxial strains possibly because they more closely mimic physiologic strain profiles. The application of these biophysical stimuli for engineering 3D skeletal muscle grafts is non-trivial and typically requires custom-designed bioreactors used in combination with biomaterial scaffolds. Consideration of the physical properties of these scaffolds is critical for effective transmission of the applied strains to encapsulated cells. Taken together, these studies demonstrate that biomimetic tensile strain generally results in improved myogenic outcomes in myogenic progenitors and differentiated myoblasts. However, for 3D systems, the optimization of the strain regimen may require the entire system - cells, biomaterials, and

  2. MicroRNA-31 controls phenotypic modulation of human vascular smooth muscle cells by regulating its target gene cellular repressor of E1A-stimulated genes

    SciTech Connect

    Wang, Jie; Yan, Cheng-Hui; Li, Yang; Xu, Kai; Tian, Xiao-Xiang; Peng, Cheng-Fei; Tao, Jie; Sun, Ming-Yu; Han, Ya-Ling

    2013-05-01

    Phenotypic modulation of vascular smooth muscle cells (VSMCs) plays a critical role in the pathogenesis of a variety of proliferative vascular diseases. The cellular repressor of E1A-stimulated genes (CREG) has been shown to play an important role in phenotypic modulation of VSMCs. However, the mechanism regulating CREG upstream signaling remains unclear. MicroRNAs (miRNAs) have recently been found to play a critical role in cell differentiation via target-gene regulation. This study aimed to identify a miRNA that binds directly to CREG, and may thus be involved in CREG-mediated VSMC phenotypic modulation. Computational analysis indicated that miR-31 bound to the CREG mRNA 3′ untranslated region (3′-UTR). miR-31 was upregulated in quiescent differentiated VSMCs and downregulated in proliferative cells stimulated by platelet-derived growth factor and serum starvation, demonstrating a negative relationship with the VSMC differentiation marker genes, smooth muscle α-actin, calponin and CREG. Using gain-of-function and loss-of-function approaches, CREG and VSMC differentiation marker gene expression levels were shown to be suppressed by a miR-31 mimic, but increased by a miR-31 inhibitor at both protein and mRNA levels. Notably, miR-31 overexpression or inhibition affected luciferase expression driven by the CREG 3′-UTR containing the miR-31 binding site. Furthermore, miR-31-mediated VSMC phenotypic modulation was inhibited in CREG-knockdown human VSMCs. We also determined miR-31 levels in the serum of patients with coronary artery disease (CAD), with or without in stent restenosis and in healthy controls. miR-31 levels were higher in the serum of CAD patients with restenosis compared to CAD patients without restenosis and in healthy controls. In summary, these data demonstrate that miR-31 not only directly binds to its target gene CREG and modulates the VSMC phenotype through this interaction, but also can be an important biomarker in diseases involving VSMC

  3. Altered ROS production, NF-κB activation and Interleukin-6 gene expression induced by electrical stimulation of in dystrophic mdx skeletal muscle cells

    PubMed Central

    Henríquez-Olguín, Carlos; Altamirano, Francisco; Valladares, Denisse; López, José R.; Allen, Paul D.; Jaimovich, Enrique

    2015-01-01

    . Exposure to LPS induced a dramatic increase in both NF-κB and IL-6 expression in both wt and mdx myotubes, suggesting that the altered IL-6 gene expression after ES in mdx muscle cells is due to dysregulation of Ca2+ release and ROS production, both of which impinge on NF-κB signaling. IL-6 is a key metabolic modulator that is released by skeletal muscle to coordinate a multi-systemic response (liver, muscle, and adipocytes) during physical exercise; the alteration of this response in dystrophic muscles may contribute to an abnormal response to contraction and exercise. PMID:25857619

  4. A selective ACAT-1 inhibitor, K-604, stimulates collagen production in cultured smooth muscle cells and alters plaque phenotype in apolipoprotein E-knockout mice.

    PubMed

    Yoshinaka, Yasunobu; Shibata, Haruki; Kobayashi, Hideyuki; Kuriyama, Hiroki; Shibuya, Kimiyuki; Tanabe, Sohei; Watanabe, Takuya; Miyazaki, Akira

    2010-11-01

    Acyl-coenzyme A:cholesterol O-acyltransferase-1 (ACAT-1) plays an essential role in macrophage foam cell formation and progression of atherosclerosis. We developed a potent and selective ACAT-1 inhibitor, K-604, and tested its effects in apoE-knockout mice. Administration of K-604 to 8-week-old apoE-knockout mice for 12 weeks at a dose of 60 mg/kg/day significantly reduced macrophage-positive area and increased collagen-positive area in atherosclerotic plaques in the aorta without affecting plasma cholesterol levels or lesion areas, indicating direct plaque-modulating effects of K-604 on vascular walls independent of plasma cholesterol levels. Pactimibe, a nonselective inhibitor of ACAT-1 and ACAT-2, reduced plasma cholesterol levels but did not affect macrophage- or collagen-positive areas. The size of macrophages and cholesteryl ester contents in the aorta were reduced by K-604. Exposure of cultured human aortic smooth muscle cells to K-604 resulted in increased procollagen type 1 contents in the culture supernatant and increased procollagen type 1 mRNA levels. Procollagen production was unaffected by pactimibe even at a concentration that inhibited cholesterol esterification to the basal level. Thus, the plaque-modulating effects of K-604 can be explained by stimulation of procollagen production independent of ACAT inhibition in addition to potent inhibition of macrophage ACAT-1.

  5. Lobaric Acid Inhibits VCAM-1 Expression in TNF-α-Stimulated Vascular Smooth Muscle Cells via Modulation of NF-κB and MAPK Signaling Pathways.

    PubMed

    Kwon, Ii-Seul; Yim, Joung-Han; Lee, Hong-Kum; Pyo, Suhkneung

    2016-01-01

    Lichens have been known to possess multiple biological activities, including anti-proliferative and anti-inflammatory activities. Vascular cell adhesion molecule-1 (VCAM-1) may play a role in the development of atherosclerosis. Hence, VCAM-1 is a possible therapeutic target in the treatment of the inflammatory disease. However, the effect of lobaric acid on VCAM-1 has not yet been investigated and characterized. For this study, we examined the effect of lobaric acid on the inhibition of VCAM-1 in tumor necrosis factor-alpha (TNF-α)-stimulated mouse vascular smooth muscle cells. Western blot and ELISA showed that the increased expression of VCAM-1 by TNF-α was significantly suppressed by the pre-treatment of lobaric acid (0.1-10 μg/ml) for 2 h. Lobaric acid abrogated TNF-α-induced NF-κB activity through preventing the degradation of IκB and phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 mitogen activated protein (MAP) kinase. Lobaric acid also inhibited the expression of TNF-α receptor 1 (TNF-R1). Overall, our results suggest that lobaric acid inhibited VCAM-1 expression through the inhibition of p38, ERK, JNK and NF-κB signaling pathways, and downregulation of TNF-R1 expression. Therefore, it is implicated that lobaric acid may suppress inflammation by altering the physiology of the atherosclerotic lesion.

  6. Skeletal muscle satellite cells

    NASA Technical Reports Server (NTRS)

    Schultz, E.; McCormick, K. M.

    1994-01-01

    Evidence now suggests that satellite cells constitute a class of myogenic cells that differ distinctly from other embryonic myoblasts. Satellite cells arise from somites and first appear as a distinct myoblast type well before birth. Satellite cells from different muscles cannot be functionally distinguished from one another and are able to provide nuclei to all fibers without regard to phenotype. Thus, it is difficult to ascribe any significant function to establishing or stabilizing fiber type, even during regeneration. Within a muscle, satellite cells exhibit marked heterogeneity with respect to their proliferative behavior. The satellite cell population on a fiber can be partitioned into those that function as stem cells and those which are readily available for fusion. Recent studies have shown that the cells are not simply spindle shaped, but are very diverse in their morphology and have multiple branches emanating from the poles of the cells. This finding is consistent with other studies indicating that the cells have the capacity for extensive migration within, and perhaps between, muscles. Complexity of cell shape usually reflects increased cytoplasmic volume and organelles including a well developed Golgi, and is usually associated with growing postnatal muscle or muscles undergoing some form of induced adaptive change or repair. The appearance of activated satellite cells suggests some function of the cells in the adaptive process through elaboration and secretion of a product. Significant advances have been made in determining the potential secretion products that satellite cells make. The manner in which satellite cell proliferative and fusion behavior is controlled has also been studied. There seems to be little doubt that cellcell coupling is not how satellite cells and myofibers communicate. Rather satellite cell regulation is through a number of potential growth factors that arise from a number of sources. Critical to the understanding of this form

  7. Decreased S100A9 Expression Promoted Rat Airway Smooth Muscle Cell Proliferation by Stimulating ROS Generation and Inhibiting p38 MAPK

    PubMed Central

    Yin, Lei-Miao; Han, Xiao-Jie; Duan, Ting-Ting; Xu, Yu-Dong; Ulloa, Luis

    2016-01-01

    Background. Asthma is a disease with a core abnormality in airway smooth muscle function, and the proliferation of airway smooth muscle cells (ASMCs) plays a pivotal role in asthma airway remodeling. Our previous study showed that S100A9 (S100 calcium-binding protein A9; 400 and 800 ng/mL) significantly inhibited rat ASMCs proliferation at 48 h, and 50–800 ng/mL S100A9 (50, 100, 200, 400, and 800 ng/mL) also induced a lasting effect by significantly inhibiting rat ASMCs proliferation at 72 h in a dose-dependent manner. However, the intracellular effects of S100A9 on ASMCs proliferation remain unknown. Methods. Rat ASMCs with stable S100A9 knockdown were generated using short hairpin RNA. The effects of decreased S100A9 expression on cellular proliferation, the production of reactive oxygen species (ROS), and p38 MAPK pathway protein expression were examined. Results. Decreased intracellular S100A9 expression significantly promoted platelet-derived growth factor-induced rat ASMCs proliferation and increased ROS production. The antioxidative agent N-acetylcysteine significantly inhibited rat ASMCs proliferation. Western blot results showed that the decreased intracellular S100A9 expression significantly inhibited p38 MAPK phosphorylation. Conclusion. Decreased S100A9 expression promoted rat ASMCs proliferation by stimulating ROS generation and inhibiting p38 MAPK. Our study may provide novel insights into the regulation of asthma airway remodeling. PMID:28050155

  8. Acute stimulation of transplanted neurons improves motoneuron survival, axon growth, and muscle reinnervation.

    PubMed

    Grumbles, Robert M; Liu, Yang; Thomas, Christie M; Wood, Patrick M; Thomas, Christine K

    2013-06-15

    Few options exist for treatment of pervasive motoneuron death after spinal cord injury or in neurodegenerative diseases such as amyotrophic lateral sclerosis. Local transplantation of embryonic motoneurons into an axotomized peripheral nerve is a promising approach to arrest the atrophy of denervated muscles; however, muscle reinnervation is limited by poor motoneuron survival. The aim of the present study was to test whether acute electrical stimulation of transplanted embryonic neurons promotes motoneuron survival, axon growth, and muscle reinnervation. The sciatic nerve of adult Fischer rats was transected to mimic the widespread denervation seen after disease or injury. Acutely dissociated rat embryonic ventral spinal cord cells were transplanted into the distal tibial nerve stump as a neuron source for muscle reinnervation. Immediately post-transplantation, the cells were stimulated at 20 Hz for 1 h. Other groups were used to control for the cell transplantation and stimulation. When neurons were stimulated acutely, there were significantly more neurons, including cholinergic neurons, 10 weeks after transplantation. This led to enhanced numbers of myelinated axons, reinnervation of more muscle fibers, and more medial and lateral gastrocnemius muscles were functionally connected to the transplant. Reinnervation reduced muscle atrophy significantly. These data support the concept that electrical stimulation rescues transplanted motoneurons and facilitates muscle reinnervation.

  9. Andrographolide Inhibits Nuclear Factor-κB Activation through JNK-Akt-p65 Signaling Cascade in Tumor Necrosis Factor-α-Stimulated Vascular Smooth Muscle Cells

    PubMed Central

    Chen, Yu-Ying; Hsieh, Cheng-Ying; Lee, Lin-Wen; Sheu, Joen-Rong

    2014-01-01

    Critical vascular inflammation leads to vascular dysfunction and cardiovascular diseases, including abdominal aortic aneurysms, hypertension, and atherosclerosis. Andrographolide is the most active and critical constituent isolated from the leaves of Andrographis paniculata, a herbal medicine widely used for treating anti-inflammation in Asia. In this study, we investigated the mechanisms of the inhibitory effects of andrographolide in vascular smooth muscle cells (VSMCs) exposed to a proinflammatory stimulus, tumor necrosis factor-α (TNF-α). Treating TNF-α-stimulated VSMCs with andrographolide suppressed the expression of inducible nitric oxide synthase in a concentration-dependent manner. A reduction in TNF-α-induced c-Jun N-terminal kinase (JNK), Akt, and p65 phosphorylation was observed in andrographolide-treated VSMCs. However, andrographolide affected neither IκBα degradation nor p38 mitogen-activated protein kinase or extracellular signal-regulated kinase 1/2 phosphorylation under these conditions. Both treatment with LY294002, a phosphatidylinositol 3-kinase/Akt inhibitor, and treatment with SP600125, a JNK inhibitor, markedly reversed the andrographolide-mediated inhibition of p65 phosphorylation. In addition, LY294002 and SP600125 both diminished Akt phosphorylation, whereas LY294002 had no effects on JNK phosphorylation. These results collectively suggest that therapeutic interventions using andrographolide can benefit the treatment of vascular inflammatory diseases, and andrographolide-mediated inhibition of NF-κB activity in TNF-α-stimulated VSMCs occurs through the JNK-Akt-p65 signaling cascade, an IκBα-independent mechanism. PMID:25114952

  10. Acute and temporal expression of tumor necrosis factor (TNF)-α-stimulated gene 6 product, TSG6, in mesenchymal stem cells creates microenvironments required for their successful transplantation into muscle tissue.

    PubMed

    Torihashi, Shigeko; Ho, Mioko; Kawakubo, Yuji; Komatsu, Kazumi; Nagai, Masataka; Hirayama, Yuri; Kawabata, Yuka; Takenaka-Ninagawa, Nana; Wanachewin, Orawan; Zhuo, Lisheng; Kimata, Koji

    2015-09-11

    Previously, we demonstrated that when mesenchymal stem cells (MSCs) from mouse ES cells were transplanted into skeletal muscle, more than 60% of them differentiated into muscles in the crush-injured tibialis anterior muscle in vivo, although MSCs neither differentiated nor settled in the intact muscle. Microenvironments, including the extracellular matrix between the injured and intact muscle, were quite different. In the injured muscle, hyaluronan (HA), heavy chains of inter-α-inhibitor (IαI), CD44, and TNF-α-stimulated gene 6 product (TSG-6) increased 24-48 h after injury, although basement membrane components of differentiated muscle such as perlecan, laminin, and type IV collagen increased gradually 4 days after the crush. We then investigated the microenvironments crucial for cell transplantation, using the lysate of C2C12 myotubules for mimicking injured circumstances in vivo. MSCs settled in the intact muscle when they were transplanted together with the C2C12 lysate or TSG6. MSCs produced and released TSG6 when they were cultured with C2C12 lysates in vitro. MSCs pretreated with the lysate also settled in the intact muscle. Furthermore, MSCs whose TSG6 was knocked down by shRNA, even if transplanted or pretreated with the lysate, could not settle in the muscle. Immunofluorescent staining showed that HA and IαI always co-localized or were distributed closely, suggesting formation of covalent complexes, i.e. the SHAP-HA complex in the presence of TSG6. Thus, TSG6, HA, and IαI were crucial factors for the settlement and probably the subsequent differentiation of MSCs.

  11. Acute and Temporal Expression of Tumor Necrosis Factor (TNF)-α-stimulated Gene 6 Product, TSG6, in Mesenchymal Stem Cells Creates Microenvironments Required for Their Successful Transplantation into Muscle Tissue*

    PubMed Central

    Torihashi, Shigeko; Ho, Mioko; Kawakubo, Yuji; Komatsu, Kazumi; Nagai, Masataka; Hirayama, Yuri; Kawabata, Yuka; Takenaka-Ninagawa, Nana; Wanachewin, Orawan; Zhuo, Lisheng; Kimata, Koji

    2015-01-01

    Previously, we demonstrated that when mesenchymal stem cells (MSCs) from mouse ES cells were transplanted into skeletal muscle, more than 60% of them differentiated into muscles in the crush-injured tibialis anterior muscle in vivo, although MSCs neither differentiated nor settled in the intact muscle. Microenvironments, including the extracellular matrix between the injured and intact muscle, were quite different. In the injured muscle, hyaluronan (HA), heavy chains of inter-α-inhibitor (IαI), CD44, and TNF-α-stimulated gene 6 product (TSG-6) increased 24–48 h after injury, although basement membrane components of differentiated muscle such as perlecan, laminin, and type IV collagen increased gradually 4 days after the crush. We then investigated the microenvironments crucial for cell transplantation, using the lysate of C2C12 myotubules for mimicking injured circumstances in vivo. MSCs settled in the intact muscle when they were transplanted together with the C2C12 lysate or TSG6. MSCs produced and released TSG6 when they were cultured with C2C12 lysates in vitro. MSCs pretreated with the lysate also settled in the intact muscle. Furthermore, MSCs whose TSG6 was knocked down by shRNA, even if transplanted or pretreated with the lysate, could not settle in the muscle. Immunofluorescent staining showed that HA and IαI always co-localized or were distributed closely, suggesting formation of covalent complexes, i.e. the SHAP-HA complex in the presence of TSG6. Thus, TSG6, HA, and IαI were crucial factors for the settlement and probably the subsequent differentiation of MSCs. PMID:26178374

  12. A muscle stem cell for every muscle: variability of satellite cell biology among different muscle groups.

    PubMed

    Randolph, Matthew E; Pavlath, Grace K

    2015-01-01

    The human body contains approximately 640 individual skeletal muscles. Despite the fact that all of these muscles are composed of striated muscle tissue, the biology of these muscles and their associated muscle stem cell populations are quite diverse. Skeletal muscles are affected differentially by various muscular dystrophies (MDs), such that certain genetic mutations specifically alter muscle function in only a subset of muscles. Additionally, defective muscle stem cells have been implicated in the pathology of some MDs. The biology of muscle stem cells varies depending on the muscles with which they are associated. Here we review the biology of skeletal muscle stem cell populations of eight different muscle groups. Understanding the biological variation of skeletal muscles and their resident stem cells could provide valuable insight into mechanisms underlying the susceptibility of certain muscles to myopathic disease.

  13. A muscle stem cell for every muscle: variability of satellite cell biology among different muscle groups

    PubMed Central

    Randolph, Matthew E.; Pavlath, Grace K.

    2015-01-01

    The human body contains approximately 640 individual skeletal muscles. Despite the fact that all of these muscles are composed of striated muscle tissue, the biology of these muscles and their associated muscle stem cell populations are quite diverse. Skeletal muscles are affected differentially by various muscular dystrophies (MDs), such that certain genetic mutations specifically alter muscle function in only a subset of muscles. Additionally, defective muscle stem cells have been implicated in the pathology of some MDs. The biology of muscle stem cells varies depending on the muscles with which they are associated. Here we review the biology of skeletal muscle stem cell populations of eight different muscle groups. Understanding the biological variation of skeletal muscles and their resident stem cells could provide valuable insight into mechanisms underlying the susceptibility of certain muscles to myopathic disease. PMID:26500547

  14. Spatially distributed sequential stimulation reduces muscle fatigue during neuromuscular electrical stimulation.

    PubMed

    Sayenko, Dimitry G; Popovic, Milos R; Masani, Kei

    2013-01-01

    A critical limitation with neuromuscular electrical stimulation (NMES) approach is the rapid onset of muscle fatigue during repeated contractions, which results in the muscle force decay and slowing of muscle contractile properties. In our previous study, we demonstrated that spatially distributed sequential stimulation (SDSS) show a drastically greater fatigue-reducing ability compared to a conventional, single active electrode stimulation (SES) with an individual with spinal cord injury when applied for plantar flexors. The purpose of the present study is to explore the fatigue-reducing ability of SDSS for major lower limb muscle groups in the able-bodied population as well as individuals with spinal cord injury (SCI). SDSS was delivered through four active electrodes applied to the muscle of interest, sending a stimulation pulse to each electrode one after another with 90° phase shift between successive electrodes. For comparison, SES was delivered through one active electrode. For both modes of stimulation, the resultant frequency to the muscle as a whole was 40 Hz. Using corresponding protocols for the fatiguing stimulation, we demonstrated the fatigue-reducing ability of SDSS by higher fatigue indices as compared with single active electrode setup for major leg muscles in both subject groups. The present work verifies and extends reported findings on the effectiveness of using spatially distributed sequential stimulation in the leg muscles to reduce muscle fatigue. Application of this technique can improve the usefulness of NMES during functional movements in the clinical setup.

  15. Microcurrent Electrical Neuromuscular Stimulation Facilitates Regeneration of Injured Skeletal Muscle in Mice

    PubMed Central

    Fujiya, Hiroto; Ogura, Yuji; Ohno, Yoshitaka; Goto, Ayumi; Nakamura, Ayane; Ohashi, Kazuya; Uematsu, Daiki; Aoki, Haruhito; Musha, Haruki; Goto, Katsumasa

    2015-01-01

    Conservative therapies, mainly resting care for the damaged muscle, are generally used as a treatment for skeletal muscle injuries (such as muscle fragmentation). Several past studies reported that microcurrent electrical neuromuscular stimulation (MENS) facilitates a repair of injured soft tissues and shortens the recovery period. However, the effects of MENS on the regeneration in injured skeletal muscle are still unclear. The purpose of this study was to investigate the effect of MENS on the regenerative process of injured skeletal muscle and to elucidate whether satellite cells in injured skeletal muscle are activated by MENS by using animal models. Male C57BL/6J mice, aged 7 weeks old, were used (n = 30). Mice were randomly divided into two groups: (1) cardiotoxin (CTX)-injected (CX, n = 15) and (2) CTX-injected with MENS treatment (MX, n=15) groups. CTX was injected into tibialis anterior muscle (TA) of mice in CX and MX groups to initiate the necrosis-regeneration cycle of the muscle. TA was dissected 1, 2, and 3 weeks after the injection. Muscle weight, muscle protein content, the mean cross-sectional areas of muscle fibers, the relative percentage of fibers having central nuclei, and the number of muscle satellite cells were evaluated. MENS facilitated the recovery of the muscle dry weight and protein content relative to body weight, and the mean cross-sectional areas of muscle fibers in CTX-induced injured TA muscle. The number of Pax7-positive muscle satellite cells was increased by MENS during the regenerating period. Decrease in the percentages of fibers with central nuclei after CTX-injection was facilitated by MENS. MENS may facilitate the regeneration of injured skeletal muscles by activating the regenerative potential of skeletal muscles. Key points Microcurrent electrical neuromuscular stimulation (MENS) facilitated the recovery of the relative muscle dry weight, the relative muscle protein content, and the mean cross-sectional areas of muscle

  16. Microcurrent electrical neuromuscular stimulation facilitates regeneration of injured skeletal muscle in mice.

    PubMed

    Fujiya, Hiroto; Ogura, Yuji; Ohno, Yoshitaka; Goto, Ayumi; Nakamura, Ayane; Ohashi, Kazuya; Uematsu, Daiki; Aoki, Haruhito; Musha, Haruki; Goto, Katsumasa

    2015-06-01

    Conservative therapies, mainly resting care for the damaged muscle, are generally used as a treatment for skeletal muscle injuries (such as muscle fragmentation). Several past studies reported that microcurrent electrical neuromuscular stimulation (MENS) facilitates a repair of injured soft tissues and shortens the recovery period. However, the effects of MENS on the regeneration in injured skeletal muscle are still unclear. The purpose of this study was to investigate the effect of MENS on the regenerative process of injured skeletal muscle and to elucidate whether satellite cells in injured skeletal muscle are activated by MENS by using animal models. Male C57BL/6J mice, aged 7 weeks old, were used (n = 30). Mice were randomly divided into two groups: (1) cardiotoxin (CTX)-injected (CX, n = 15) and (2) CTX-injected with MENS treatment (MX, n=15) groups. CTX was injected into tibialis anterior muscle (TA) of mice in CX and MX groups to initiate the necrosis-regeneration cycle of the muscle. TA was dissected 1, 2, and 3 weeks after the injection. Muscle weight, muscle protein content, the mean cross-sectional areas of muscle fibers, the relative percentage of fibers having central nuclei, and the number of muscle satellite cells were evaluated. MENS facilitated the recovery of the muscle dry weight and protein content relative to body weight, and the mean cross-sectional areas of muscle fibers in CTX-induced injured TA muscle. The number of Pax7-positive muscle satellite cells was increased by MENS during the regenerating period. Decrease in the percentages of fibers with central nuclei after CTX-injection was facilitated by MENS. MENS may facilitate the regeneration of injured skeletal muscles by activating the regenerative potential of skeletal muscles. Key pointsMicrocurrent electrical neuromuscular stimulation (MENS) facilitated the recovery of the relative muscle dry weight, the relative muscle protein content, and the mean cross-sectional areas of muscle

  17. Denervated muscles in humans: limitations and problems of currently used functional electrical stimulation training protocols.

    PubMed

    Kern, Helmut; Hofer, Christian; Mödlin, Michaela; Forstner, Claudia; Raschka-Högler, Doris; Mayr, Winfried; Stöhr, Hans

    2002-03-01

    Prior clinical work showed that electrical stimulation therapy with exponential current is able to slow down atrophy and maintain the muscle during nonpermanent flaccid paralysis. However, exponential currents are not sufficient for long-term therapy of denervated degenerated muscles (DDMs). We initiated a European research project investigating the rehabilitation strategies in humans, but also studying the underlying basic scientific knowledge of muscle regeneration from satellite cells or myoblast activity in animal experiments. In our prior study, we were able to show that high-intensity stimulation of DDMs is possible. At the beginning of training, only single muscle twitches can be elicited by biphasic pulses with durations of 120-150 ms. Later, tetanic contraction of the muscle with special stimulation parameters (pulse duration of 30-50 ms, stimulation frequency of 16-25 Hz, pulse amplitudes of up to 250 mA) can improve the structural and metabolic state of the DDMs. Because there are no nerve endings for conduction of stimuli, large-size, anatomically shaped electrodes are used. This ensures an even contraction of the whole muscle. Contrary to the current clinical knowledge, we were able to stimulate and train denervated muscle 15-20 years after denervation. The estimated amount of muscle fibers that have to be restored is about 2-4 million fibers in each m. quadriceps. To rebuild such a large number of muscle fibers takes up to 3-4 years. Despite constant stimulation parameters and training protocols, there is a high variation in the developed contraction force and fatigue resistance of the muscle during the first years of functional electrical stimulation.

  18. Butyrate, an HDAC inhibitor, stimulates interplay between different posttranslational modifications of histone H3 and differently alters G1-specific cell cycle proteins in vascular smooth muscle cells.

    PubMed

    Mathew, Omana P; Ranganna, Kasturi; Yatsu, Frank M

    2010-12-01

    HDACs and HATs regulate histone acetylation, an epigenetic modification that controls chromatin structure and through it, gene expression. Butyrate, a dietary HDAC inhibitor, inhibits VSMC proliferation, a crucial factor in atherogenesis, and the principle mechanism in arterial and in-stent restenosis. Here, the link between antiproliferation action of butyrate and the portraits of global covalent modifications of histone H3 that it induces are characterized to understand the mechanics of butyrate-arrested VSMC proliferation. Analysis of histone H3 modifications specific to butyrate arrested VSMC proliferation display induction of histone H3-Lysine9 acetylation, inhibition of histone H3-Serine10 phosphorylation, reduction of histone H3-Lysine9 dimethylation and stimulation of histone H3-Lysine4 di-methylation, which is linked to transcriptional activation, cell cycle/mitosis, transcriptional suppression and activation, respectively. Conversely, untreated VSMCs exhibit inhibition of H3-Lysine9 acetylation, induction of H3-Serine10 phosphorylation, stimulation of H3-Lysine9 di-methylation and reduction in H3-Lysine4 di-methylation. Butyrate's cooperative effects on H3-Lysine9 acetylation and H3-Serine10 phosphorylation, and contrasting effects on di-methylation of H3-Lysine9 and H3-Lysine4 suggests that the interplay between these site-specific modifications cause distinct chromatin alterations that allow cyclin D1 and D3 induction, G1-specific cdk4, cdk6 and cdk2 downregulation, and upregulation of cdk inhibitors, p15INK4b and p21Cip1. Regardless of butyrate's effect on D-type cyclins, downregulation of G1-specific cdks and upregulation of cdk inhibitors by butyrate prevents cell cycle progression by failing to inactivate Rb. Overall, through chromatin remodeling, butyrate appears to differentially alter G1-specific cell cycle proteins to ensure proliferation arrest of VSMCs, a crucial cellular component of blood vessel wall.

  19. Na+-K+ pump stimulation improves contractility in damaged muscle fibers.

    PubMed

    Clausen, Torben

    2005-12-01

    Skeletal muscles have a high content of Na+-K+-ATPase, an enzyme that is identical to the Na+-K+ pump, a transport system mediating active extrusion of Na+ from the cells and accumulation of K+ in the cells. The major function of the Na+-K+ pumps is to maintain the concentration gradients for Na+ and K+ across the plasma membrane. This generates the resting membrane potential, allowing the propagation of action potentials, excitation-contraction coupling and force development. Muscles exposed to (1) high extracellular K+ or (2) low extracellular Na+ show a considerable loss of force. A similar force decline is elicited by (3) increasing Na+ permeability or (4) decreasing K+ permeability. Under all of these four conditions, stimulation of the Na+-K+ pumps can restore contractility. Following exposure to electroporation or fatiguing stimulation, muscle cell membranes develop leaks to Na+ and K+ and a partially reversible loss of force. The restoration of force is abolished by blocking the Na+-K+ pumps and markedly improved by stimulating the Na+-K+ pumps with beta 2-agonists, calcitonin gene-related peptide, or dbcAMP. These observations indicate that the Na+-K+ pumps are important for the functional compensation of the commonly occurring loss of muscle cell integrity. Stimulation of the Na+-K+ pumps with beta 2-agonists or other agents may be of therapeutic value in the treatment of muscle cell damage induced by electrical shocks, prolonged exercise, burns, or bruises.

  20. Cross talk between MMP2-Spm-Cer-S1P and ERK1/2 in proliferation of pulmonary artery smooth muscle cells under angiotensin II stimulation.

    PubMed

    Chowdhury, Animesh; Sarkar, Jaganmay; Pramanik, Pijush Kanti; Chakraborti, Tapati; Chakraborti, Sajal

    2016-08-01

    The aim of the present study is to establish the mechanism associated with the proliferation of PASMCs under ANG II stimulation. The results showed that treatment of PASMCs with ANG II induces an increase in cell proliferation and 100 nM was the optimum concentration for maximum increase in proliferation of the cells. Pretreatment of the cells with AT1, but not AT2, receptor antagonist inhibited ANG II induced cell proliferation. Pretreatment with pharmacological and genetic inhibitors of sphingomyelinase (SMase) and sphingosine kinase (SPHK) prevented ANG II-induced cell proliferation. ANG II has also been shown to induce SMase activity, SPHK phosphorylation and S1P production. In addition, ANG II caused an increase in proMMP-2 expression and activation, ERK1/2 phosphorylation and NADPH oxidase activation. Upon inhibition of MMP-2, SMase activity and S1P level were curbed leading to inhibition of cell proliferation. SPHK was phosphorylated by ERK1/2 during ET-1 stimulation of the cells. ANG II-induced ERK1/2 phosphorylation and proMMP-2 expression and activation in the cells were abrogated upon inhibition of NADPH oxidase activity. Overall, NADPH oxidase plays an important role in proMMP-2 expression and activation and that MMP-2 mediated SMC proliferation occurs through the involvement of Spm-Cer-S1P signaling axis under ANG II stimulation of PASMCs.

  1. Oxygen transport and intracellular bioenergetics on stimulated cat skeletal muscle.

    PubMed

    Nioka, S; McCully, K; McClellan, G; Park, Jane; Chance, B

    2003-01-01

    A unique multiparameter recording of skeletal muscle bioenergetics, biochemistry and biomechanics has permitted determination of novel relationships among hemodynamics, cellular high-energy metabolites and mitochondrial bioenergetics in feline skeletal muscle. The study utilizes 31P NMR, NIR, and NADH fluorescence spectrophotometry, biochemical assays and muscle performance. Seven cats were anesthetized and mechanically ventilated. Calf muscles were stimulated through sciatic nerve electrical stimulation and tension was monitored by a strain gauge connected to the Achilles tendon. We stimulated the muscle to produce several workloads up to Vmax. We also changed FiO2 from normoxia to hypoxia for each %Vmax. From these results, the most sensitive indicators of cellular hypoxia leading to a reduction in muscle performance can be determined. Hemoglobin deoxygenation generally does not correlate with cellular hypoxia, although when the HbO2 drops below 30% saturation there is an increased incidence of cellular hypoxia. The [ADP], which is known to regulate mitochondrial function, has a close relation to the work, not to the hypoxia. On the other hand, the mitochondrial NADH does respond to cellular PO2. The degree of oxidation (NADH decrease) due to the ATP flux shifts with oxygen availability in mild to moderate hypoxia (at FiO2 down to 9%). As cellular hypoxia causes decreases in muscle performance (moderate to severe hypoxia), NADH is being reduced rather than oxidized with increasing workloads.

  2. Interdigitated array of Pt electrodes for electrical stimulation and engineering of aligned muscle tissue.

    PubMed

    Ahadian, Samad; Ramón-Azcón, Javier; Ostrovidov, Serge; Camci-Unal, Gulden; Hosseini, Vahid; Kaji, Hirokazu; Ino, Kosuke; Shiku, Hitoshi; Khademhosseini, Ali; Matsue, Tomokazu

    2012-09-21

    Engineered skeletal muscle tissues could be useful for applications in tissue engineering, drug screening, and bio-robotics. It is well-known that skeletal muscle cells are able to differentiate under electrical stimulation (ES), with an increase in myosin production, along with the formation of myofibers and contractile proteins. In this study, we describe the use of an interdigitated array of electrodes as a novel platform to electrically stimulate engineered muscle tissues. The resulting muscle myofibers were analyzed and quantified in terms of their myotube characteristics and gene expression. The engineered muscle tissues stimulated through the interdigitated array of electrodes demonstrated superior performance and maturation compared to the corresponding tissues stimulated through a conventional setup (i.e., through Pt wires in close proximity to the muscle tissue). In particular, the ES of muscle tissue (voltage 6 V, frequency 1 Hz and duration 10 ms for 1 day) through the interdigitated array of electrodes resulted in a higher degree of C2C12 myotube alignment (∼80%) as compared to ES using Pt wires (∼65%). In addition, higher amounts of C2C12 myotube coverage area, myotube length, muscle transcription factors and protein biomarkers were found for myotubes stimulated through the interdigitated array of electrodes compared to those stimulated using the Pt wires. Due to the wide array of potential applications of ES for two- and three-dimensional (2D and 3D) engineered tissues, the suggested platform could be employed for a variety of cell and tissue structures to more efficiently investigate their response to electrical fields.

  3. Effects on contralateral muscles after unilateral electrical muscle stimulation and exercise.

    PubMed

    Song, Yafeng; Forsgren, Sture; Yu, Jiguo; Lorentzon, Ronny; Stål, Per S

    2012-01-01

    It is well established that unilateral exercise can produce contralateral effects. However, it is unclear whether unilateral exercise that leads to muscle injury and inflammation also affects the homologous contralateral muscles. To test the hypothesis that unilateral muscle injury causes contralateral muscle changes, an experimental rabbit model with unilateral muscle overuse caused by a combination of electrical muscle stimulation and exercise (EMS/E) was used. The soleus and gastrocnemius muscles of both exercised and non-exercised legs were analyzed with enzyme- and immunohistochemical methods after 1, 3 and 6 weeks of repeated EMS/E. After 1 w of unilateral EMS/E there were structural muscle changes such as increased variability in fiber size, fiber splitting, internal myonuclei, necrotic fibers, expression of developmental MyHCs, fibrosis and inflammation in the exercised soleus muscle. Only limited changes were found in the exercised gastrocnemius muscle and in both non-exercised contralateral muscles. After 3 w of EMS/E, muscle fiber changes, presence of developmental MyHCs, inflammation, fibrosis and affections of nerve axons and AChE production were observed bilaterally in both the soleus and gastrocnemius muscles. At 6 w of EMS/E, the severity of these changes significantly increased in the soleus muscles and infiltration of fat was observed bilaterally in both the soleus and the gastrocnemius muscles. The affections of the muscles were in all three experimental groups restricted to focal regions of the muscle samples. We conclude that repetitive unilateral muscle overuse caused by EMS/E overtime leads to both degenerative and regenerative tissue changes and myositis not only in the exercised muscles, but also in the homologous non-exercised muscles of the contralateral leg. Although the mechanism behind the contralateral changes is unclear, we suggest that the nervous system is involved in the cross-transfer effects.

  4. Stimulation of AMP-activated protein kinase and enhancement of basal glucose uptake in muscle cells by quercetin and quercetin glycosides, active principles of the antidiabetic medicinal plant Vaccinium vitis-idaea.

    PubMed

    Eid, Hoda M; Martineau, Louis C; Saleem, Ammar; Muhammad, Asim; Vallerand, Diane; Benhaddou-Andaloussi, Ali; Nistor, Lidia; Afshar, Arvind; Arnason, John T; Haddad, Pierre S

    2010-07-01

    Several medicinal plants that stimulate glucose uptake in skeletal muscle cells were identified from among species used by the Cree of Eeyou Istchee of northern Quebec to treat symptoms of diabetes. This study aimed to elucidate the mechanism of action of one of these products, the berries of Vaccinium vitis idaea, as well as to isolate and identify its active constituents using a classical bioassay-guided fractionation approach. Western immunoblot analysis in C2C12 muscle cells revealed that the ethanol extract of the berries stimulated the insulin-independent AMP-activated protein kinase (AMPK) pathway. The extract mildly inhibited ADP-stimulated oxygen consumption in isolated mitochondria, an effect consistent with metabolic stress and the ensuing stimulation of AMPK. This mechanism is highly analogous to that of Metformin. Fractionation guided by glucose uptake activity resulted in the isolation of ten compounds. The two most active, quercetin-3-O-glycosides, enhanced glucose uptake by 38-59% (50 muM; 18 h treatment) in the absence of insulin. Quercetin aglycone, a minor constituent, stimulated uptake by 37%. The quercetin glycosides and the aglycone stimulated the AMPK pathway at concentrations of 25-100 muM, but only the aglycone inhibited ATP synthase in isolated mitochondria (by 34 and 79% at 25 and 100 muM, respectively). This discrepancy suggests that the activity of the glycosides may require hydrolysis to the aglycone form. These findings indicate that quercetin and quercetin 3-O-glycosides are responsible for the antidiabetic activity of V. vitis crude berry extract mediated by AMPK. These common plant products may thus have potential applications for the prevention and treatment of insulin resistance and other metabolic diseases.

  5. Nonparametric Model of Smooth Muscle Force Production During Electrical Stimulation.

    PubMed

    Cole, Marc; Eikenberry, Steffen; Kato, Takahide; Sandler, Roman A; Yamashiro, Stanley M; Marmarelis, Vasilis Z

    2017-03-01

    A nonparametric model of smooth muscle tension response to electrical stimulation was estimated using the Laguerre expansion technique of nonlinear system kernel estimation. The experimental data consisted of force responses of smooth muscle to energy-matched alternating single pulse and burst current stimuli. The burst stimuli led to at least a 10-fold increase in peak force in smooth muscle from Mytilus edulis, despite the constant energy constraint. A linear model did not fit the data. However, a second-order model fit the data accurately, so the higher-order models were not required to fit the data. Results showed that smooth muscle force response is not linearly related to the stimulation power.

  6. A regulatory role for cAMP in phosphatidylinositol 3-kinase/p70 ribosomal S6 kinase-mediated DNA synthesis in platelet-derived-growth-factor-stimulated bovine airway smooth-muscle cells.

    PubMed Central

    Scott, P H; Belham, C M; al-Hafidh, J; Chilvers, E R; Peacock, A J; Gould, G W; Plevin, R

    1996-01-01

    In bovine airway smooth-muscle cells platelet-derived growth factor (PDGF) and endothelin (Et-1) stimulate sustained and comparable activation of mitogen-activated protein kinase (MAP kinase) but display very different mitogenic efficacies, with PDGF inducing 50 times more DNA synthesis than Et-1. To examine additional signalling pathways which may be involved in this response, we investigated the role of phosphatidylinositol 3-kinase (PtdIns 3-kinase)/p70 ribosomal protein S6 kinase (p70s6k) in mediating PDGF- and Et-1-induced mitogenesis, and whether inhibition of this pathway may underly the ability of cAMP to inhibit cell proliferation. PDGF stimulated an increase in PtdIns 3-kinase activity and a sustained 15-fold increase in p70s6k activity that was abolished by both wortmannin and rapamycin. Et-1, however, stimulated only a 2-fold increase in p70s6k activity that was rapamycin-sensitive but wortmannin-insensitive. DNA synthesis stimulated by PDGF (50-fold) and Et-1 (2-fold) followed a similar pattern of inhibition. Pretreatment with phorbol ester did not affect p70s6k activation in response to PDGF. Raising intracellular cAMP levels using forskolin, however, resulted in a marked time-dependent inhibition of p70s6k activity, a decrease in the tyrosine phosphorylation of the PtdIns 3-kinase p85 subunit and reduced PtdIns 3-kinase activity. Forskolin also inhibited PDGF-stimulated DNA synthesis. These results suggest that PtdIns 3-kinase-dependent activation of p70s6k may determine mitogenic efficacy of agonists that generate comparable MAP kinase signals. Negative regulation of PtdIns 3-kinase by cAMP may play an important role in the inhibition of airway smooth-muscle cell proliferation. PMID:8836145

  7. Tongue muscle plasticity following hypoglossal nerve stimulation in aged rats

    PubMed Central

    Connor, Nadine P.; Russell, John A.; Jackson, Michelle A.; Kletzien, Heidi; Wang, Hao; Schaser, Allison J.; Leverson, Glen E.; Zealear, David L.

    2012-01-01

    Introduction Age-related decreases in tongue muscle mass and strength have been reported. It may be possible to prevent age-related tongue muscle changes using neuromuscular electrical stimulation (NMES). Our hypothesis was that alterations in muscle contractile properties and myosin heavy chain composition would be found following NMES. Methods Fifty-four young, middle-aged and old Fischer 344/Brown Norway rats were included. Twenty-four rats underwent bilateral electrical stimulation of the hypoglossal nerves for 8 weeks and were compared with control or sham rats. Muscle contractile properties and myosin heavy chain (MHC) in the genioglossus (GG), styloglossus (SG) and hyoglossus (HG) muscles were examined. Results In comparison with unstimulated control rats, we found reduced muscle fatigue, increased contraction and half decay times and increased twitch and tetanic tension. Increased Type I MHC was found, except for GG in old and middle-aged rats. Discussion Transitions in tongue muscle contractile properties and phenotype were found following NMES. PMID:23169566

  8. Electrical stimulation of embryonic neurons for 1 hour improves axon regeneration and the number of reinnervated muscles that function.

    PubMed

    Liu, Yang; Grumbles, Robert M; Thomas, Christine K

    2013-07-01

    Motoneuron death after spinal cord injury or disease results in muscle denervation, atrophy, and paralysis. We have previously transplanted embryonic ventral spinal cord cells into the peripheral nerve to reinnervate denervated muscles and to reduce muscle atrophy, but reinnervation was incomplete. Here, our aim was to determine whether brief electrical stimulation of embryonic neurons in the peripheralnerve changes motoneuron survival, axon regeneration, and muscle reinnervation and function because neural depolarization is crucial for embryonic neuron survival and may promote activity-dependent axon growth. At 1 week after denervation by sciatic nerve section, embryonic day 14 to 15 cells were purified for motoneurons, injected into the tibial nerve of adult Fischer rats, and stimulated immediatelyfor up to 1 hour. More myelinated axons were present in tibial nerves 10 weeks after transplantation when transplants had been stimulated acutely at 1 Hz for 1 hour. More muscles were reinnervated if the stimulation treatment lasted for 1 hour. Reinnervation reduced muscle atrophy, with or without the stimulation treatment. These data suggest that brief stimulation of embryonic neurons promotes axon growth, which has a long-term impact on muscle reinnervation and function. Muscle reinnervation is important because it may enable the use of functional electrical stimulation to restore limb movements.

  9. Electrical Stimulation of Embryonic Neurons for 1 Hour Improves Axon Regeneration and the Number of Reinnervated Muscles that Function

    PubMed Central

    Liu, Yang; Grumbles, Robert M.; Thomas, Christine K.

    2013-01-01

    Motoneuron death following spinal cord injury or disease results in muscle denervation, atrophy, and paralysis. We have previously transplanted embryonic ventral spinal cord cells into peripheral nerve to reinnervate denervated muscles and to reduce muscle atrophy, but reinnervation was incomplete. Here, our aim was to determine whether brief electrical stimulation of embryonic neurons in peripheral nerve changes motoneuron survival, axon regeneration, and muscle reinnervation and function because neural depolarization is crucial for embryonic neuron survival and may promote activity-dependent axon growth. At 1 week after denervation by sciatic nerve section, embryonic day 14-15 cells were purified for motoneurons, injected into the tibial nerve of adult Fischer rats, and stimulated immediately for up to 1 hour. More myelinated axons were present in tibial nerves when transplants had been stimulated at 1 Hz for 1 hour at 10 weeks following transplantation. More muscles were reinnervated if the stimulation treatment lasted for 1 hour. Reinnervation reduced muscle atrophy, with or without the stimulation treatment. These data suggest that brief stimulation of embryonic neurons promotes axon growth, which has a long-term impact on muscle reinnervation and function. Muscle reinnervation is important because it may enable the use of functional electrical stimulation to restore limb movements. PMID:23771218

  10. Effects of chronic electrical stimulation on paralyzed expiratory muscles

    PubMed Central

    DiMarco, Anthony F.; Kowalski, Krzysztof E.

    2013-01-01

    Following spinal cord injury, the expiratory muscles develop significant disuse atrophy characterized by reductions in their weight, fiber cross-sectional area, and force-generating capacity. We determined the extent to which these physiological alterations can be prevented with electrical stimulation. Because a critical function of the expiratory muscles is cough generation, an important goal was the maintenance of maximal force production. In a cat model of spinal cord injury, short periods of high-frequency lower thoracic electrical spinal cord stimulation (SCS) at the T10 level (50 Hz, 15 min, twice/day, 5 days/wk) were initiated 2 wk following spinalization and continued for a 6-mo period. Airway pressure (P)-generating capacity was determined by SCS. Five acute, spinalized animals served as controls. Compared with controls, initial P fell from 43.9 ± 1.0 to 41.8 ± 0.7 cmH2O (not significant) in the chronic animals. There were small reductions in the weight of the external oblique, internal oblique, transverses abdominis, internal intercostal, and rectus abdominis muscles (not significant for each). There were no significant changes in the population of fast muscle fibers. Because prior studies (Kowalski KE, Romaniuk JR, DiMarco AF. J Appl Physiol 102: 1422-1428, 2007) have demonstrated significant atrophy following spinalization in this model, these results indicate that expiratory muscle atrophy can be prevented by the application of short periods of daily high-frequency stimulation. Because the frequency of stimulation is similar to the expected pattern of clinical use for cough generation, the daily application of electrical stimulation could potentially serve the dual purpose of maintenance of expiratory muscle function and airway clearance. PMID:18403449

  11. An Implanted, Stimulated Muscle Powered Piezoelectric Generator

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth; Gustafson, Kenneth; Kilgore, Kevin

    2007-01-01

    A totally implantable piezoelectric generator system able to harness power from electrically activated muscle could be used to augment the power systems of implanted medical devices, such as neural prostheses, by reducing the number of battery replacement surgeries or by allowing periods of untethered functionality. The features of our generator design are no moving parts and the use of a portion of the generated power for system operation and regulation. A software model of the system has been developed and simulations have been performed to predict the output power as the system parameters were varied within their constraints. Mechanical forces that mimic muscle forces have been experimentally applied to a piezoelectric generator to verify the accuracy of the simulations and to explore losses due to mechanical coupling. Depending on the selection of system parameters, software simulations predict that this generator concept can generate up to approximately 700 W of power, which is greater than the power necessary to drive the generator, conservatively estimated to be 50 W. These results suggest that this concept has the potential to be an implantable, self-replenishing power source and further investigation is underway.

  12. What does chronic electrical stimulation teach us about muscle plasticity?

    PubMed

    Pette, D; Vrbová, G

    1999-06-01

    The model of chronic low-frequency stimulation for the study of muscle plasticity was developed over 30 years ago. This protocol leads to a transformation of fast, fatigable muscles toward slower, fatigue-resistant ones. It involves qualitative and quantitative changes of all elements of the muscle fiber studied so far. The multitude of stimulation-induced changes makes it possible to establish the full adaptive potential of skeletal muscle. Both functional and structural alterations are caused by orchestrated exchanges of fast protein isoforms with their slow counterparts, as well as by altered levels of expression. This remodeling of the muscle fiber encompasses the major, myofibrillar proteins, membrane-bound and soluble proteins involved in Ca2+ dynamics, and mitochondrial and cytosolic enzymes of energy metabolism. Most transitions occur in a coordinated, time-dependent manner and result from altered gene expression, including transcriptional and posttranscriptional processes. This review summarizes the advantages of chronic low-frequency stimulation for studying activity-induced changes in phenotype, and its potential for investigating regulatory mechanisms of gene expression. The potential clinical relevance or utility of the technique is also considered.

  13. 21 CFR 890.5860 - Ultrasound and muscle stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasound and muscle stimulator. 890.5860 Section 890.5860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... of the body ultrasonic energy at a frequency beyond 20 kilohertz and that is intended to...

  14. 21 CFR 890.5860 - Ultrasound and muscle stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ultrasound and muscle stimulator. 890.5860 Section 890.5860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... of the body ultrasonic energy at a frequency beyond 20 kilohertz and that is intended to...

  15. 21 CFR 890.5860 - Ultrasound and muscle stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ultrasound and muscle stimulator. 890.5860 Section 890.5860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... of the body ultrasonic energy at a frequency beyond 20 kilohertz and that is intended to...

  16. 21 CFR 890.5860 - Ultrasound and muscle stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ultrasound and muscle stimulator. 890.5860 Section 890.5860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... of the body ultrasonic energy at a frequency beyond 20 kilohertz and that is intended to...

  17. 21 CFR 890.1850 - Diagnostic muscle stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Diagnostic muscle stimulator. 890.1850 Section 890.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1850...

  18. 21 CFR 890.5850 - Powered muscle stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Powered muscle stimulator. 890.5850 Section 890.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5850 Powered...

  19. 21 CFR 890.5850 - Powered muscle stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Powered muscle stimulator. 890.5850 Section 890.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5850 Powered...

  20. 21 CFR 890.1850 - Diagnostic muscle stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Diagnostic muscle stimulator. 890.1850 Section 890.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1850...

  1. 21 CFR 890.5850 - Powered muscle stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Powered muscle stimulator. 890.5850 Section 890.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5850 Powered...

  2. 21 CFR 890.1850 - Diagnostic muscle stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Diagnostic muscle stimulator. 890.1850 Section 890.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1850...

  3. 21 CFR 890.5860 - Ultrasound and muscle stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ultrasound and muscle stimulator. 890.5860 Section 890.5860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices §...

  4. 21 CFR 890.5850 - Powered muscle stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered muscle stimulator. 890.5850 Section 890.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5850 Powered...

  5. 21 CFR 890.5850 - Powered muscle stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Powered muscle stimulator. 890.5850 Section 890.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5850 Powered...

  6. 21 CFR 890.1850 - Diagnostic muscle stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic muscle stimulator. 890.1850 Section 890.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1850...

  7. 21 CFR 890.1850 - Diagnostic muscle stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Diagnostic muscle stimulator. 890.1850 Section 890.1850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1850...

  8. Counteracting Muscle Atrophy using Galvanic Stimulation of the Vestibular System

    NASA Technical Reports Server (NTRS)

    Fox, Robert A.; Polyakov, Igor

    1999-01-01

    The unloading of weight bearing from antigravity muscles during space flight produces significant muscle atrophy and is one of the most serious health problems facing the space program. Various exercise regimens have been developed and used either alone or in combination with pharmacological techniques to ameliorate this atrophy, but no effective countermeasure exists for this problem. The research in this project was conducted to evaluate the potential use of vestibular galvanic stimulation (VGS) to prevent muscle atrophy resulting from unloading of weight bearing from antigravity muscles. This approach was developed based on two concepts related to the process of maintaining the status of the anti-gravity neuromuscular system. These two premises are: (1) The "tone," or bias on spinal motorneurons is affected by vestibular projections that contribute importantly to maintaining muscle health and status. (2) VGS can be used to modify the excitability, or 'tone' of motorneuron of antigravity muscles. Thus, the strategy is to use VGS to modify the gain of vestibular projections to antigravity muscles and thereby change the general status of these muscles.

  9. Noninvasive stimulation of human corticospinal axons innervating leg muscles.

    PubMed

    Martin, P G; Butler, J E; Gandevia, S C; Taylor, J L

    2008-08-01

    These studies investigated whether a single electrical stimulus over the thoracic spine activates corticospinal axons projecting to human leg muscles. Transcranial magnetic stimulation of the motor cortex and electrical stimulation over the thoracic spine were paired at seven interstimulus intervals, and surface electromyographic responses were recorded from rectus femoris, tibialis anterior, and soleus. The interstimulus intervals (ISIs) were set so that the first descending volley evoked by cortical stimulation had not arrived at (positive ISIs), was at the same level as (0 ISI) or had passed (negative ISIs) the site of activation of descending axons by the thoracic stimulation at the moment of its delivery. Compared with the responses to motor cortical stimulation alone, responses to paired stimuli were larger at negative ISIs but reduced at positive ISIs in all three leg muscles. This depression of responses at positive ISIs is consistent with an occlusive interaction in which an antidromic volley evoked by the thoracic stimulation collides with descending volleys evoked by cortical stimulation. The cortical and spinal stimuli activate some of the same corticospinal axons. Thus it is possible to examine the excitability of lower limb motoneuron pools to corticospinal inputs without the confounding effects of changes occurring within the motor cortex.

  10. Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

    PubMed

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots.

  11. Electrical Stimulation of Coleopteran Muscle for Initiating Flight

    PubMed Central

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots. PMID:27050093

  12. Microcurrent electrical nerve stimulation facilitates regrowth of mouse soleus muscle.

    PubMed

    Ohno, Yoshitaka; Fujiya, Hiroto; Goto, Ayumi; Nakamura, Ayane; Nishiura, Yuka; Sugiura, Takao; Ohira, Yoshinobu; Yoshioka, Toshitada; Goto, Katsumasa

    2013-01-01

    Microcurrent electrical nerve stimulation (MENS) has been used to facilitate recovery from skeletal muscle injury. However, the effects of MENS on unloading-associated atrophied skeletal muscle remain unclear. Effects of MENS on the regrowing process of unloading-associated atrophied skeletal muscle were investigated. Male C57BL/6J mice (10-week old) were randomly assigned to untreated normal recovery (C) and MENS-treated (M) groups. Mice of both groups are subjected to continuous hindlimb suspension (HS) for 2 weeks followed by 7 days of ambulation recovery. Mice in M group were treated with MENS for 60 min 1, 3, and 5 days following HS, respectively, under anesthesia. The intensity, the frequency, and the pulse width of MENS were set at 10 μA, 0.3 Hz, and 250 msec, respectively. Soleus muscles were dissected before and immediately after, 1, 3 and 7 days after HS. Soleus muscle wet weight and protein content were decreased by HS. The regrowth of atrophied soleus muscle in M group was faster than that in C group. Decrease in the reloading-induced necrosis of atrophied soleus was facilitated by MENS. Significant increases in phosphorylated levels of p70 S6 kinase and protein kinase B (Akt) in M group were observed, compared with C group. These observations are consistent with that MENS facilitated regrowth of atrophied soleus muscle. MENS may be a potential extracellular stimulus to activate the intracellular signals involved in protein synthesis.

  13. Satellite cells: the architects of skeletal muscle.

    PubMed

    Chang, Natasha C; Rudnicki, Michael A

    2014-01-01

    The outstanding regenerative capacity of skeletal muscle is attributed to the resident muscle stem cell termed satellite cell. Satellite cells are essential for skeletal muscle regeneration as they ultimately provide the myogenic precursors that rebuild damaged muscle tissue. Satellite cells characteristically are a heterogeneous population of stem cells and committed progenitor cells. Delineation of cellular hierarchy and understanding how lineage fate choices are determined within the satellite cell population will be invaluable for the advancement of muscle regenerative therapies.

  14. Use of flow, electrical, and mechanical stimulation to promote engineering of striated muscles.

    PubMed

    Rangarajan, Swathi; Madden, Lauran; Bursac, Nenad

    2014-07-01

    The field of tissue engineering involves design of high-fidelity tissue substitutes for predictive experimental assays in vitro and cell-based regenerative therapies in vivo. Design of striated muscle tissues, such as cardiac and skeletal muscle, has been particularly challenging due to a high metabolic demand and complex cellular organization and electromechanical function of the native tissues. Successful engineering of highly functional striated muscles may thus require creation of biomimetic culture conditions involving medium perfusion, electrical and mechanical stimulation. When optimized, these external cues are expected to synergistically and dynamically activate important intracellular signaling pathways leading to accelerated muscle growth and development. This review will discuss the use of different types of tissue culture bioreactors aimed at providing conditions for enhanced structural and functional maturation of engineered striated muscles.

  15. Use of flow, electrical, and mechanical stimulation to promote engineering of striated muscles

    PubMed Central

    Rangarajan, Swathi; Madden, Lauran; Bursac, Nenad

    2014-01-01

    The field of tissue engineering involves design of high-fidelity tissue substitutes for predictive experimental assays in vitro and cell-based regenerative therapies in vivo. Design of striated muscle tissues, such as cardiac and skeletal muscle, has been particularly challenging due to a high metabolic demand and complex cellular organization and electromechanical function of the native tissues. Successful engineering of highly functional striated muscles may thus require creation of biomimetic culture conditions involving medium perfusion, electrical and mechanical stimulation. When optimized, these external cues are expected to synergistically and dynamically activate important intracellular signaling pathways leading to accelerated muscle growth and development. This review will discuss the use of different types of tissue culture bioreactors aimed at providing conditions for enhanced structural and functional maturation of engineered striated muscles. PMID:24366526

  16. Mechanisms limiting glycogen storage in muscle during prolonged insulin stimulation

    SciTech Connect

    Richter, E.A.; Hansen, S.A.; Hansen, B.F. )

    1988-11-01

    The extent to which muscle glycogen concentrations can be increased during exposure to maximal insulin concentrations and abundant glucose was investigated in the isolated perfused rat hindquarter preparation. Perfusion for 7 h in the presence of 20,000 {mu}U/ml insulin and 11-13 mM glucose increased muscle glycogen concentrations to maximal values 2, 3, and 3.5 times above normal fed levels in fast-twitch white, slow-twitch red, and fast-twitch red fibers, respectively. Glucose uptake decreased from 34.9 {mu}mol{center dot}g{sup {minus}1}{center dot}h{sup {minus}1} at 0 h to 7.5 after 7 h of perfusion. During the perfusion muscle glycogen synthase activity decreased and free intracellular glucose and glucose 6-phosphate increased indicating that glucose disposal was impaired. However, glucose transport as measured by the uptake of 3-O-({sup 14}C)methyl-D-glucose was also markedly decreased after 5 and 7 h of perfusion compared with initial values. Total muscle water concentration decreased during glycogen loading of the muscles. Mechanisms limiting glycogen storage under maximal insulin stimulation include impaired insulin-stimulated membrane transport of glucose as well as impaired intracellular glucose disposal.

  17. Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation.

    PubMed

    Gay, André; Aimonetti, Jean-Marc; Roll, Jean-Pierre; Ribot-Ciscar, Edith

    2015-07-30

    In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (-51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (-38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief.

  18. PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells.

    PubMed

    Ho, Tsung-Chuan; Chiang, Yi-Pin; Chuang, Chih-Kuang; Chen, Show-Li; Hsieh, Jui-Wen; Lan, Yu-Wen; Tsao, Yeou-Ping

    2015-08-01

    In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser(93)-Leu(112)) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2'-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration.

  19. 21 CFR 884.5940 - Powered vaginal muscle stimulator for therapeutic use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Powered vaginal muscle stimulator for therapeutic... Gynecological Therapeutic Devices § 884.5940 Powered vaginal muscle stimulator for therapeutic use. (a) Identification. A powered vaginal muscle stimulator is an electrically powered device designed to...

  20. 21 CFR 884.5940 - Powered vaginal muscle stimulator for therapeutic use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered vaginal muscle stimulator for therapeutic... Gynecological Therapeutic Devices § 884.5940 Powered vaginal muscle stimulator for therapeutic use. (a) Identification. A powered vaginal muscle stimulator is an electrically powered device designed to...

  1. 21 CFR 884.5940 - Powered vaginal muscle stimulator for therapeutic use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Powered vaginal muscle stimulator for therapeutic... Gynecological Therapeutic Devices § 884.5940 Powered vaginal muscle stimulator for therapeutic use. (a) Identification. A powered vaginal muscle stimulator is an electrically powered device designed to...

  2. 21 CFR 884.5940 - Powered vaginal muscle stimulator for therapeutic use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Powered vaginal muscle stimulator for therapeutic... Gynecological Therapeutic Devices § 884.5940 Powered vaginal muscle stimulator for therapeutic use. (a) Identification. A powered vaginal muscle stimulator is an electrically powered device designed to...

  3. 21 CFR 884.5940 - Powered vaginal muscle stimulator for therapeutic use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Powered vaginal muscle stimulator for therapeutic... Gynecological Therapeutic Devices § 884.5940 Powered vaginal muscle stimulator for therapeutic use. (a) Identification. A powered vaginal muscle stimulator is an electrically powered device designed to...

  4. Recovery Effect of the Muscle Fatigue by the Magnetic Stimulation

    NASA Astrophysics Data System (ADS)

    Uchida, Kousuke; Nuruki, Atsuo; Tsujimura, Sei-Ichi; Tamari, Youzou; Yunokuchi, Kazutomo

    The purpose of this study is to investigate the effect of magnetic stimulation for muscle fatigue. The six healthy subjects participated in the experiment with the repetition grasp using a hand dynamometer. The measurement of EMG (electromyography) and MMG (mechanomyography) is performed on the left forearm. All subjects performed MVC (maximum voluntary contraction), and repeated exercise in 80%MVC after the MVC measurement. The repetition task was entered when display muscular strength deteriorated. We used an EMG and MMG for the measurement of the muscle fatigue. Provided EMG and MMG waves were calculated integral calculus value (iEMG, and iMMG). The result of iEMG and iMMG were divided by muscular strength, because we calculate integral calculus value per the unit display muscular strength. The result of our study, we found recovery effect by the magnetic stimulation in voluntarily muscular strength and iEMG. However, we can not found in a figure of iMMG.

  5. A novel bioreactor for stimulating skeletal muscle in vitro.

    PubMed

    Donnelly, Kenneth; Khodabukus, Alastair; Philp, Andrew; Deldicque, Louise; Dennis, Robert G; Baar, Keith

    2010-08-01

    For over 300 years, scientists have understood that stimulation, in the form of an electrical impulse, is required for normal muscle function. More recently, the role of specific parameters of the electrical impulse (i.e., the pulse amplitude, pulse width, and work-to-rest ratio) has become better appreciated. However, most existing bioreactor systems do not permit sufficient control over these parameters. Therefore, the aim of the current study was to engineer an inexpensive muscle electrical stimulation bioreactor to apply physiologically relevant electrical stimulation patterns to tissue-engineered muscles and monolayers in culture. A low-powered microcontroller and a DC-DC converter were used to power a pulse circuit that converted a 4.5 V input to outputs of up to 50 V, with pulse widths from 0.05 to 4 ms, and frequencies up to 100 Hz (with certain operational limitations). When two-dimensional cultures were stimulated at high frequencies (100 Hz), this resulted in an increase in the rate of protein synthesis (at 12 h, control [CTL] = 5.0 + or - 0.16; 10 Hz = 5.0 + or - 0.07; and 100 Hz = 5.5 + or - 0.13 fmol/min/mg) showing that this was an anabolic signal. When three-dimensional engineered muscles were stimulated at 0.1 ms and one or two times rheobase, stimulation improved force production (CTL = 0.07 + or - 0.009; 1.25 V/mm = 0.10 + or - 0.011; 2.5 V/mm = 0.14146 + or - 0.012; and 5 V/mm = 0.03756 + or - 0.008 kN/mm(2)) and excitability (CTL = 0.53 + or - 0.022; 1.25 V/mm = 0.44 + or - 0.025; 2.5 V/mm = 0.41 + or - 0.012; and 5 V/mm = 0.60 + or - 0.021 V/mm), suggesting enhanced maturation. Together, these data show that the physiology and function of muscles can be improved in vitro using a bioreactor that allows the control of pulse amplitude, pulse width, pulse frequency, and work-to-rest ratio.

  6. The effects of functional electrical stimulation on muscle tone and stiffness of stroke patients

    PubMed Central

    Moon, Sang-Hyun; Choi, Jung-Hyun; Park, Si-Eun

    2017-01-01

    [Purpose] The purpose of this study was to determine the effects of functional electrical stimulation on muscle tone and stiffness in stroke patients. [Subjects and Methods] Ten patients who had suffered from stroke were recruited. The intervention was functional electrical stimulation on ankle dorsiflexor muscle (tibialis anterior). The duration of functional electrical stimulation was 30 minutes, 5 times a week for 6 weeks. The Myoton was used a measure the muscle tone and stiffness of the gastrocnemius muscle (medial and lateral part) on paretic side. [Results] In the assessment of muscle tone, medial and lateral part of gastrocnemius muscle showed differences before and after the experiment. Muscle stiffness of medial gastrocnemius muscle showed differences, and lateral gastrocnemius muscle showed differences before and after the experiment. The changes were greater in stiffness scores than muscle tone. [Conclusion] These results suggest that FES on ankle dorsiflexor muscle had a positive effect on muscle tone and stiffness of stroke patients. PMID:28265148

  7. Muscle plasticity: comparison of a 30-Hz burst with 10-Hz continuous stimulation.

    PubMed

    Ferguson, A S; Stone, H E; Roessmann, U; Burke, M; Tisdale, E; Mortimer, J T

    1989-03-01

    The changes in the contractile properties induced by a 30-Hz phasic stimulation paradigm were measured and compared with the changes induced by a 10-Hz continuous stimulation paradigm. The study was performed on the tibialis anterior muscles of cats with one paradigm applied to one hindlimb muscle and the other to the contralateral limb. Both hindlimb muscles received the same number of stimuli in a day, making the average stimulation frequency 10 Hz. Two periods of daily stimulation were studied, 8 and 24 h/day. Muscles stimulated at 30 Hz produced greater overall tetanic tension and, during a prolonged stimulation test, exerted a greater mean tension than muscles stimulated at 10 Hz (50 and 32% increase for animals stimulated for 8 and 24 h/day, respectively). Muscle mass was least reduced and fewer pathological abnormalities were observed in the muscles stimulated at 30 Hz. There were no apparent differences in the histochemistry or biochemistry between muscles stimulated at 10 and 30 Hz, which could account for these differences in muscle properties. These results indicate the 30-Hz paradigm may be better suited than 10 Hz continuous stimulation for applications requiring sustained muscle tension such as correction of scoliosis or muscle conditioning for motor prostheses.

  8. Transcranial magnetic stimulation with the maximum voluntary muscle contraction facilitates motor neuron excitability and muscle force.

    PubMed

    Touge, Tetsuo; Urai, Yoshiteru; Ikeda, Kazuyo; Kume, Kodai; Deguchi, Kazushi

    2012-01-01

    Three trials of transcranial magnetic stimulation (TMS) during the maximum voluntary muscle contraction (MVC) were repeated at 15-minute intervals for 1 hour to examine the effects on motor evoked potentials (MEPs) in the digital muscles and pinching muscle force before and after 4 high-intensity TMSs (test 1 condition) or sham TMS (test 2 condition) with MVC. Under the placebo condition, real TMS with MVC was administered only before and 1 hour after the sham TMS with MVC. Magnetic stimulation at the foramen magnum level (FMS) with MVC was performed by the same protocol as that for the test 2 condition. As a result, MEP sizes in the digital muscles significantly increased after TMS with MVC under test conditions compared with the placebo conditions (P < 0.05). Pinching muscle force was significantly larger 45 minutes and 1 hour after TMS with MVC under the test conditions than under the placebo condition (P < 0.05). FMS significantly decreased MEP amplitudes 60 minutes after the sham TMS with MVC (P < 0.005). The present results suggest that intermittently repeated TMS with MVC facilitates motor neuron excitabilities and muscle force. However, further studies are needed to confirm the effects of TMS with MVC and its mechanism.

  9. An ethanol root extract of Cynanchum wilfordii containing acetophenones suppresses the expression of VCAM-1 and ICAM-1 in TNF-α-stimulated human aortic smooth muscle cells through the NF-κB pathway

    PubMed Central

    KOO, HYUN JUNG; SOHN, EUN-HWA; PYO, SUHKNEUNG; WOO, HAN GOO; PARK, DAE WON; HAM, YOUNG-MIN; JANG, SEON-A; PARK, SOO-YEONG; KANG, SE CHAN

    2015-01-01

    The root of Cynanchum wilfordii (C. wilfordii) contains several biologically active compounds which have been used as traditional medicines in Asia. In the present study, we evaluated the anti-inflammatory effects of an ethanol root extract of C. wilfordii (CWE) on tumor necrosis factor (TNF)-α-stimulated human aortic smooth muscle cells (HASMCs). The inhibitory effects of CWE on vascular cell adhesion molecule (VCAM)-1 expression under an optimum extraction condition were examined. CWE suppressed the expression of VCAM-1 and ICAM-1 and the adhesion of THP-1 monocytes to the TNF-α-stimulated HASMCs. Consistent with the in vitro observations, CWE inhibited the aortic expression of ICAM-1 and VCAM-1 in atherogenic diet-fed mice. CWE also downregulated the expression of nuclear factor-κB (NF-κB p65) and its uclear translocation in the stimulated HASMCs. In order to identify the active components in CWE, we re-extracted CWE using several solvents, and found that the ethyl acetate fraction was the most effective in suppressing the expression of VCAM-1 and ICAM-1. Four major acetophenones were purified from the ethyl acetate fraction, and two components, p-hydroxyacetophenone and cynandione A, potently inhibited the expression of ICAM-1 and VCAM-1 in the stimulated HASMCs. We assessed and determined the amounts of these two active components from CWE, and our results suggested that the root of C. wilfordii and its two bioactive acetophenones may be used for the prevention and treatment of atherosclerosis and vascular inflammatory diseases. PMID:25716870

  10. Dynamic skeletal muscle stimulation and its potential in bone adaptation

    PubMed Central

    Qin, Y-X.; Lam, H.; Ferreri, S.; Rubin, C.

    2016-01-01

    To identify mechanotransductive signals for combating musculoskeletal deterioration, it is essential to determine the components and mechanisms critical to the anabolic processes of musculoskeletal tissues. It is hypothesized that the interaction between bone and muscle may depend on fluid exchange in these tissues by mechanical loading. It has been shown that intramedullary pressure (ImP) and low-level bone strain induced by muscle stimulation (MS) has the potential to mitigate bone loss induced by disuse osteopenia. Optimized MS signals, i.e., low-intensity and high frequency, may be critical in maintaining bone mass and mitigating muscle atrophy. The objectives for this review are to discuss the potential for MS to induce ImP and strains on bone, to regulate bone adaptation, and to identify optimized stimulation frequency in the loading regimen. The potential for MS to regulate blood and fluid flow will also be discussed. The results suggest that oscillatory MS regulates fluid dynamics with minimal mechanical strain in bone. The response was shown to be dependent on loading frequency, serving as a critical mediator in mitigating bone loss. A specific regimen of dynamic MS may be optimized in vivo to attenuate disuse osteopenia and serve as a biomechanical intervention in the clinical setting. PMID:20190376

  11. Chronic muscle stimulation improves ischaemic muscle performance in patients with peripheral vascular disease.

    PubMed

    Tsang, G M; Green, M A; Crow, A J; Smith, F C; Beck, S; Hudlicka, O; Shearman, C P

    1994-07-01

    There is currently no established treatment for intermittent claudication with proven long term benefit. Exercise classes have been shown to improve walking distance. Chronic electromyostimulation (CEMS) a method of stimulating skeletal muscle has effects on normal muscle which may also benefit claudicants. We investigated the effects of one month of CEMS on claudicants in a single blind placebo controlled study. Patients were randomised to either CEMS (treatment) or transcutaneous nerve stimulation (TENS) placebo. The effects of the two modalities were assessed using the conventional measures of claudicating distance (CD), maximum walking distance (MWD), ankle-brachial pressure index (ABPI) and pressure recovery time (PRT). Muscle performance was assessed by the fatigue index (FI) a technique determining the decrease in ischaemic muscle response to repeated contraction. After 4 weeks treatment the CEMS group showed significant improvements in their median CD (88 to 111) and MWD (118 to 158); this was not seen in the control group. Muscle performance also increased significantly during the 4 weeks of treatment in the CEMS group but not in the control group. These changes were not maintained after CEMS was stopped. This pilot study suggests that CEMS may well have a role to play in the treatment of intermittent claudication though a number of further studies need to be undertaken.

  12. Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells

    PubMed Central

    Tedesco, Francesco Saverio; Dellavalle, Arianna; Diaz-Manera, Jordi; Messina, Graziella; Cossu, Giulio

    2010-01-01

    Skeletal muscle damaged by injury or by degenerative diseases such as muscular dystrophy is able to regenerate new muscle fibers. Regeneration mainly depends upon satellite cells, myogenic progenitors localized between the basal lamina and the muscle fiber membrane. However, other cell types outside the basal lamina, such as pericytes, also have myogenic potency. Here, we discuss the main properties of satellite cells and other myogenic progenitors as well as recent efforts to obtain myogenic cells from pluripotent stem cells for patient-tailored cell therapy. Clinical trials utilizing these cells to treat muscular dystrophies, heart failure, and stress urinary incontinence are also briefly outlined. PMID:20051632

  13. Multifunctional cyclic D,L-α-peptide architectures stimulate non-insulin dependent glucose uptake in skeletal muscle cells and protect them against oxidative stress.

    PubMed

    Shapira, Renana; Rudnick, Safra; Daniel, Bareket; Viskind, Olga; Aisha, Vered; Richman, Michal; Ayasolla, Kamesh R; Perelman, Alex; Chill, Jordan H; Gruzman, Arie; Rahimipour, Shai

    2013-09-12

    Oxidative stress directly correlates with the early onset of vascular complications and the progression of peripheral insulin resistance in diabetes. Accordingly, exogenous antioxidants augment insulin sensitivity in type 2 diabetic patients and ameliorate its clinical signs. Herein, we explored the unique structural and functional properties of the abiotic cyclic D,L-α-peptide architecture as a new scaffold for developing multifunctional agents to catalytically decompose ROS and stimulate glucose uptake. We showed that His-rich cyclic D,L-α-peptide 1 is very stable under high H2O2 concentrations, effectively self-assembles to peptide nanotubes, and increases the uptake of glucose by increasing the translocation of GLUT1 and GLUT4. It also penetrates cells and protects them against oxidative stress induced under hyperglycemic conditions at a much lower concentration than α-lipoic acid (ALA). In vivo studies are now required to probe the mode of action and efficacy of these abiotic cyclic D,L-α-peptides as a novel class of antihyperglycemic compounds.

  14. The contractile state of rabbit papillary muscle in relation to stimulation frequency.

    PubMed Central

    Edman, K A; Jóhannsson, M

    1976-01-01

    1. The relationship between active force and stimulation frequency (0-25-5/sec) was studied at 36-37 degrees C in isolated papillary muscles of the rabbit. 2. The muscle's force producing capability at a given frequency was determined as the isometric twitch response to a test stimulus that was applied at various times after a priming period. The optimum contractile response was obtained at an interval of 0-8 sec between the test pulse and the last stimulus of the priming period. 3. The optimum contractile response exceeded the steady-state twitch amplitude at all stimulation frequencies higher than 1/sec. While the steady-state twitch resonse declined at frequencies higher than 4/sec, the optimum contractile response was steadily increased as the stimulation frequency was raised. 4. The optimum contractile response was also determined after priming the muscle with a sinusoidal a.c. pulse (field strength, 10 V (r.m.s.)/cm; frequency, 20 c/s; duration, 2-5 sec). The optimum contractile response obtained after a.c. stimulation was 2-2 times greater than the maximal steady-state response. Its absolute value was 67-3+/-6-1 mN/mm2 (mean +/-S.E. of mean, n = 6). 5. The twitch potentiation produced by priming the muscle at a given frequency decayed exponentially in two phases after optimum contractile response had been attained. The time constants of the two phases, determined after a.c. stimulation, were 2-6+/-0-8 (n = 4) and 92-0+/-13-3 sec (n = 7), respectively. 6. The optimum contractile response determined at various stimulation frequencies was linearly related to the fraction of time during which the cell membrane was depolarized (beyond -40 mV) by the action potentials. 7. The results are interpreted in terms of a two-component model of the metabolism of activator calcium in the excitation-contraction coupling. PMID:1255501

  15. Electrical stimulation using sine waveform prevents unloading-induced muscle atrophy in the deep calf muscles of rat.

    PubMed

    Tanaka, Minoru; Hirayama, Yusuke; Fujita, Naoto; Fujino, Hidemi

    2014-09-01

    The aim of this study was to compare the effects of electrical stimulation by using rectangular and sine waveforms in the prevention of deep muscle atrophy in rat calf muscles. Rats were randomly divided into the following groups: control, hindlimb unloading (HU), and HU plus electrical stimulation (ES). The animals in the ES group were electrically stimulated using rectangular waveform (RS) on the left calves and sine waveform (SS) on the right calves, twice a day, for 2 weeks during unloading. HU for 2 weeks resulted in a loss of the muscle mass, a decrease in the cross-sectional area of the muscle fibers, and overexpression of ubiquitinated proteins in the gastrocnemius and soleus muscles. In contrast, electrical stimulation with RS attenuated the HU-induced reduction in the cross-sectional area of muscle fibers and the increase of ubiquitinated proteins in the gastrocnemius muscle. However, electrical stimulation with RS failed to prevent muscle atrophy in the deep portion of the gastrocnemius and the soleus muscles. Nevertheless, electrical stimulation with SS attenuated the HU-induced muscle atrophy and the up-regulation of ubiquitinated proteins in both gastrocnemius and soleus muscles. This indicates that SS was more effective in the prevention of deep muscle atrophy than RS. Since the skin muscle layers act like the plates of a capacitor, separated by the subcutaneous adipose layer, the SS can pass through this capacitor more easily than the RS. Hence, SS can prevent the progressive loss of muscle fibers in the deep portion of the calf muscles.

  16. Factor Xa releases matrix metalloproteinase-2 (MMP-2) from human vascular smooth muscle cells and stimulates the conversion of pro-MMP-2 to MMP-2: role of MMP-2 in factor Xa-induced DNA synthesis and matrix invasion.

    PubMed

    Rauch, Bernhard H; Bretschneider, Ellen; Braun, Marina; Schrör, Karsten

    2002-05-31

    Pro-matrix metalloproteinase-2 (pro-MMP-2) is expressed in vascular smooth muscle cells (SMCs). We report that activated coagulation factor X (FXa) induces the release of MMP-2 (65 kDa) from human SMCs. In addition, FXa cleaves pro-MMP-2 (72 kDa) into MMP-2. Pro-MMP-2 and MMP-2 were determined by gelatin zymography. MMP-2 was generated in conditioned medium containing pro-MMP-2 in a concentration-dependent fashion by FXa (3 to 100 nmol/L). FX at concentrations up to 300 nmol/L was ineffective. The conversion of pro-MMP-2 to MMP-2 was inhibited by a selective FXa inhibitor (DX-9065a) at 3 to 10 micromol/L. There was a concentration-dependent induction of an intermediate MMP-2 form (68 kDa) in lysates of FXa-treated cells. This indicates that cellular mechanisms are involved in FXa-induced conversion of pro-MMP-2. As a possible biological consequence of MMP-2 activation by FXa, DNA synthesis and matrix invasion of SMCs were determined. Both were stimulated by FXa and inhibited by the selective FXa inhibitor DX-9065a and the MMP inhibitor GM 6001 but not by hirudin or aprotinin. It is concluded that stimulation of SMCs by FXa increases the levels of MMP-2 in the extracellular space and that two different mechanisms are involved: release of active MMP-2 and cleavage of secreted pro-MMP-2. Both might contribute to the mitogenic potency of FXa and FXa-stimulated matrix invasion of SMCs.

  17. Stem Cell Antigen-1 in Skeletal Muscle Function

    PubMed Central

    Bernstein, Harold S.; Samad, Tahmina; Cholsiripunlert, Sompob; Khalifian, Saami; Gong, Wenhui; Ritner, Carissa; Aurigui, Julian; Ling, Vivian; Wilschut, Karlijn J.; Bennett, Stephen; Hoffman, Julien; Oishi, Peter

    2013-01-01

    Stem cell antigen-1 (Sca-1) is a member of the Ly-6 multigene family encoding highly homologous, glycosyl-phosphatidylinositol-anchored membrane proteins. Sca-1 is expressed on muscle-derived stem cells and myogenic precursors recruited to sites of muscle injury. We previously reported that inhibition of Sca-1 expression stimulated myoblast proliferation in vitro and regulated the tempo of muscle repair in vivo. Despite its function in myoblast expansion during muscle repair, a role for Sca-1 in normal, post-natal muscle has not been thoroughly investigated. We systematically compared Sca-1-/- (KO) and Sca-1+/+ (WT) mice and hindlimb muscles to elucidate the tissue, contractile, and functional effects of Sca-1 in young and aging animals. Comparison of muscle volume, fibrosis, myofiber cross-sectional area, and Pax7+ myoblast number showed little differences between ages or genotypes. Exercise protocols, however, demonstrated decreased stamina in KO versus WT mice, with young KO mice achieving results similar to aging WT animals. In addition, KO mice did not improve with practice, while WT animals demonstrated conditioning over time. Surprisingly, myomechanical analysis of isolated muscles showed that KO young muscle generated more force and experienced less fatigue. However, KO muscle also demonstrated incomplete relaxation with fatigue. These findings suggest that Sca-1 is necessary for muscle conditioning with exercise, and that deficient conditioning in Sca-1 KO animals becomes more pronounced with age. PMID:24042315

  18. Functional electrical stimulation to the abdominal wall muscles synchronized with the expiratory flow does not induce muscle fatigue

    PubMed Central

    Okuno, Yukako; Takahashi, Ryoichi; Sewa, Yoko; Ohse, Hirotaka; Imura, Shigeyuki; Tomita, Kazuhide

    2017-01-01

    [Purpose] Continuous electrical stimulation of abdominal wall muscles is known to induce mild muscle fatigue. However, it is not clear whether this is also true for functional electrical stimulation delivered only during the expiratory phase of breathing. This study aimed to examine whether or not intermittent electrical stimulation delivered to abdominal wall muscles induces muscle fatigue. [Subjects and Methods] The subjects were nine healthy adults. Abdominal electrical stimulation was applied for 1.5 seconds from the start of expiration and then turned off during inspiration. The electrodes were attached to both sides of the abdomen at the lower margin of the 12th rib. Abdominal electrical stimulation was delivered for 15 minutes with the subject in a seated position. Expiratory flow was measured during stimulus. Trunk flexor torque and electromyography activity were measured to evaluate abdominal muscle fatigue. [Results] The mean stimulation on/off ratio was 1:2.3. The declining rate of abdominal muscle torque was 61.1 ± 19.1% before stimulus and 56.5 ± 20.9% after stimulus, not significantly different. The declining rate of mean power frequency was 47.8 ± 11.7% before stimulus and 47.9 ± 10.2% after stimulus, not significantly different. [Conclusion] It was found that intermittent electrical stimulation to abdominal muscles synchronized with the expiratory would not induce muscle fatigue. PMID:28356636

  19. Functional electrical stimulation to the abdominal wall muscles synchronized with the expiratory flow does not induce muscle fatigue.

    PubMed

    Okuno, Yukako; Takahashi, Ryoichi; Sewa, Yoko; Ohse, Hirotaka; Imura, Shigeyuki; Tomita, Kazuhide

    2017-03-01

    [Purpose] Continuous electrical stimulation of abdominal wall muscles is known to induce mild muscle fatigue. However, it is not clear whether this is also true for functional electrical stimulation delivered only during the expiratory phase of breathing. This study aimed to examine whether or not intermittent electrical stimulation delivered to abdominal wall muscles induces muscle fatigue. [Subjects and Methods] The subjects were nine healthy adults. Abdominal electrical stimulation was applied for 1.5 seconds from the start of expiration and then turned off during inspiration. The electrodes were attached to both sides of the abdomen at the lower margin of the 12th rib. Abdominal electrical stimulation was delivered for 15 minutes with the subject in a seated position. Expiratory flow was measured during stimulus. Trunk flexor torque and electromyography activity were measured to evaluate abdominal muscle fatigue. [Results] The mean stimulation on/off ratio was 1:2.3. The declining rate of abdominal muscle torque was 61.1 ± 19.1% before stimulus and 56.5 ± 20.9% after stimulus, not significantly different. The declining rate of mean power frequency was 47.8 ± 11.7% before stimulus and 47.9 ± 10.2% after stimulus, not significantly different. [Conclusion] It was found that intermittent electrical stimulation to abdominal muscles synchronized with the expiratory would not induce muscle fatigue.

  20. Generation of Electrical Power from Stimulated Muscle Contractions Evaluated

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth; Kilgore, Kevin; Ercegovic, David B.

    2004-01-01

    This project is a collaborative effort between NASA Glenn Research Center's Revolutionary Aeropropulsion Concepts (RAC) Project, part of the NASA Aerospace Propulsion and Power Program of the Aerospace Technology Enterprise, and Case Western Reserve University's Cleveland Functional Electrical Stimulation (FES) Center. The RAC Project foresees implantable power requirements for future applications such as organically based sensor platforms and robotics that can interface with the human senses. One of the goals of the FES Center is to develop a totally implantable neural prosthesis. This goal is based on feedback from patients who would prefer a system with an internal power source over the currently used system with an external power source. The conversion system under investigation would transform the energy produced from a stimulated muscle contraction into electrical energy. We hypothesize that the output power of the system will be greater than the input power necessary to initiate, sustain, and control the electrical conversion system because of the stored potential energy of the muscle. If the system can be made biocompatible, durable, and with the potential for sustained use, then the biological power source will be a viable solution.

  1. Comparison of coil designs for peripheral magnetic muscle stimulation

    NASA Astrophysics Data System (ADS)

    Goetz, S. M.; Herzog, H.-G.; Gattinger, N.; Gleich, B.

    2011-10-01

    The recent application of magnetic stimulation in rehabilitation is often said to solve key drawbacks of the established electrical method. Magnetic fields cause less pain, allow principally a better penetration of inhomogeneous biologic tissue and do not require skin contact. However, in most studies the evoked muscle force has been disappointing. In this paper, a comparison of a classical round circular geometry, a commercial muscle-stimulation coil and a novel design is presented, with special emphasis on the physical field properties. These systems show markedly different force responses for the same magnetic energy and highlight the enormous potential of different coil geometries. The new design resulted in a slope of the force recruiting curve being more than two and a half times higher than the other coils. The data were analyzed with respect to the underlying physical causes and field conditions. After a parameter-extraction approach, the results for the three coils span a two-dimensional space with clearly distinguishable degrees of freedom, which can be manipulated nearly separately and reflect the two main features of a field; the peak amplitude and its decay with the distance.

  2. Endothelial Cells Stimulate Self-Renewal and Expand Neurogenesis of Neural Stem Cells

    NASA Astrophysics Data System (ADS)

    Shen, Qin; Goderie, Susan K.; Jin, Li; Karanth, Nithin; Sun, Yu; Abramova, Natalia; Vincent, Peter; Pumiglia, Kevin; Temple, Sally

    2004-05-01

    Neural stem cells are reported to lie in a vascular niche, but there is no direct evidence for a functional relationship between the stem cells and blood vessel component cells. We show that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production. Both embryonic and adult neural stem cells respond, allowing extensive production of both projection neuron and interneuron types in vitro. Endothelial coculture stimulates neuroepithelial cell contact, activating Notch and Hes1 to promote self-renewal. These findings identify endothelial cells as a critical component of the neural stem cell niche.

  3. A Nerve Clamp Electrode Design for Indirect Stimulation of Skeletal Muscle

    DTIC Science & Technology

    2010-10-01

    Reports www.BioTechniques.com739Vol. 49 | No. 4 | 2010 Ex vivo assays to measure muscle paralysis induced by botulinum neurotoxin (BoNT) have been...Keywords: stimulating electrode; botulinum neurotoxin; skeletal muscle; paralysis A nerve clamp electrode was developed to indirectly stimulate skeletal...attached nerve. Indirect muscle stimulation is critical for studying the para- lytic actions of presynaptic-acting toxins such as botulinum neurotoxins

  4. Satellite cells in human skeletal muscle plasticity.

    PubMed

    Snijders, Tim; Nederveen, Joshua P; McKay, Bryon R; Joanisse, Sophie; Verdijk, Lex B; van Loon, Luc J C; Parise, Gianni

    2015-01-01

    Skeletal muscle satellite cells are considered to play a crucial role in muscle fiber maintenance, repair and remodeling. Our knowledge of the role of satellite cells in muscle fiber adaptation has traditionally relied on in vitro cell and in vivo animal models. Over the past decade, a genuine effort has been made to translate these results to humans under physiological conditions. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair/remodeling in response to exercise. Mounting evidence indicates that aging has a profound impact on the regulation of satellite cells in human skeletal muscle. Yet, the precise role of satellite cells in the development of muscle fiber atrophy with age remains unresolved. This review seeks to integrate recent results from in vivo human studies on satellite cell function in muscle fiber repair/remodeling in the wider context of satellite cell biology whose literature is largely based on animal and cell models.

  5. Mechanical stimulation of skeletal muscle mitigates glucocorticoid induced decreases in prostaglandin synthesis

    NASA Technical Reports Server (NTRS)

    Chromiak, Joseph A.; Vandenburgh, Herman H.

    1993-01-01

    The glucocorticoid dexamethasone (Dex) induces a decline in protein synthesis and protein content of tissue cultured, avian skeletal muscle cells, and this atrophy is attenuated by repetitive mechanical stretch. Since the prostaglandin synthesis inhibitor indomethacin mitigated this stretch attenuation of muscle atrophy, the role of prostaglandins as growth modulators in these processes was examined. Dex at 10(exp -8) M reduced PGF(sub 2(alpha)) production 55 percent - 65 percent and PGE(sub 2) production 84 - 90 percent after 24 - 72 h of incubation in static cultures. Repetitive 10 percent stretch-relaxations of the non-Dex treated cultures increased PGF(sub 2(alpha)) efflux 41 percent at 24 h and 276 percent at 72 h and increased PGE(sub 2) production 51 percent at 24 h and 236 percent at 72 h. Mechanical stimulation of Dex treated cultures increased PGF(sub 2(alpha)) production 162 percent after 24 h, thus returning PGF(sub 2(alpha)) efflux to the level of non-Dex treated cultures. At 72 h, stretch increased PGF(sub 2(alpha)) efflux 65 percent in Dex treated cultures, but PGF(sub 2(alpha)) production was 45-84 percent less than non-Dex treated cultures. Mechanical stimulation of Dex treated cultures increased PGE(sub 2) production at 24 h, but not at 72 h. Dex reduced prostaglandin H synthase (PGHS) activity in the muscle cultures by 70 percent after 8 - 24 h of incubation, and mechanical stimulation increased PGHS activity of the Dex treated cultures by 98 percent. It is concluded that repetitive mechanical stimulation attenuates the catabolic effects of Dex on cultured skeletal muscle cells in part by reversing the Dex-induced declines in PGHS activity and prostaglandin production.

  6. Taurine supplementation increases skeletal muscle force production and protects muscle function during and after high-frequency in vitro stimulation.

    PubMed

    Goodman, Craig A; Horvath, Deanna; Stathis, Christos; Mori, Trevor; Croft, Kevin; Murphy, Robyn M; Hayes, Alan

    2009-07-01

    Recent studies report that depletion and repletion of muscle taurine (Tau) to endogenous levels affects skeletal muscle contractility in vitro. In this study, muscle Tau content was raised above endogenous levels by supplementing male Sprague-Dawley rats with 2.5% (wt/vol) Tau in drinking water for 2 wk, after which extensor digitorum longus (EDL) muscles were examined for in vitro contractile properties, fatigue resistance, and recovery from fatigue after two different high-frequency stimulation bouts. Tau supplementation increased muscle Tau content by approximately 40% and isometric twitch force by 19%, shifted the force-frequency relationship upward and to the left, increased specific force by 4.2%, and increased muscle calsequestrin protein content by 49%. Force at the end of a 10-s (100 Hz) continuous tetanic stimulation was 6% greater than controls, while force at the end of the 3-min intermittent high-frequency stimulation bout was significantly higher than controls, with a 12% greater area under the force curve. For 1 h after the 10-s continuous stimulation, tetanic force in Tau-supplemented muscles remained relatively stable while control muscle force gradually deteriorated. After the 3-min intermittent bout, tetanic force continued to slowly recover over the next 1 h, while control muscle force again began to decline. Tau supplementation attenuated F(2)-isoprostane production (a sensitive indicator of reactive oxygen species-induced lipid peroxidation) during the 3-min intermittent stimulation bout. Finally, Tau transporter protein expression was not altered by the Tau supplementation. Our results demonstrate that raising Tau content above endogenous levels increases twitch and subtetanic and specific force in rat fast-twitch skeletal muscle. Also, we demonstrate that raising Tau protects muscle function during high-frequency in vitro stimulation and the ensuing recovery period and helps reduce oxidative stress during prolonged stimulation.

  7. Effects of muscle potential depression and muscle stimulation caused by different insulation coating configurations on cardiac pacemakers.

    PubMed

    Yajima, Toshimi; Yamada, Kenichi; Okubo, Naoko; Nitta, Takashi; Ochi, Masami; Shimizu, Kazuo

    2005-01-01

    Insulation coating was added to the external pacemaker surface to prevent unnecessary electric current leakage to the periphery because the pulse generator body is used as an anode in unipolar pacing. However, a model without insulation coating has recently been used, so we studied the effects on muscle potential inhibition and muscle stimulation of pacemakers in unipolar pacing with different parts of the pacemaker body coated with insulation. Case comparisons were made for the following models: insulated except for the center of one side (33, group C), insulated except for the peripheral zone (10, group E), and noncoated models (11, group N). The muscle detection threshold voltage, muscle detection threshold pulse duration, muscle potential sensing threshold (MP), and lead resistance were measured. A comparison was made of the amount of energy (En) needed to reach the muscle stimulation threshold. For MP values, there was no significant statistical difference between group C and E, whereas a significant difference was present between group C and N and between group E and N. For En values, there was a significant difference between group C and E and between group C and N, but there was no significant difference between group E and N. The muscle potential sensing threshold dose not have a change in group E and much muscle stimulation energy is needed. The muscle potential sensing threshold was low in group N, requiring much muscle stimulation energy. Based on these results, it is usually not necessary to coat the pacemaker with insulation for unipolar pacing.

  8. Peroxisome proliferator-activated receptor-γ activation enhances insulin-stimulated glucose disposal by reducing ped/pea-15 gene expression in skeletal muscle cells: evidence for involvement of activator protein-1.

    PubMed

    Ungaro, Paola; Mirra, Paola; Oriente, Francesco; Nigro, Cecilia; Ciccarelli, Marco; Vastolo, Viviana; Longo, Michele; Perruolo, Giuseppe; Spinelli, Rosa; Formisano, Pietro; Miele, Claudia; Beguinot, Francesco

    2012-12-14

    The gene network responsible for inflammation-induced insulin resistance remains enigmatic. In this study, we show that, in L6 cells, rosiglitazone- as well as pioglitazone-dependent activation of peroxisome proliferator-activated receptor-γ (PPARγ) represses transcription of the ped/pea-15 gene, whose increased activity impairs glucose tolerance in mice and humans. Rosiglitazone enhanced insulin-induced glucose uptake in L6 cells expressing the endogenous ped/pea-15 gene but not in cells expressing ped/pea-15 under the control of an exogenous promoter. The ability of PPARγ to affect ped/pea-15 expression was also lost in cells and in C57BL/6J transgenic mice expressing ped/pea-15 under the control of an exogenous promoter, suggesting that ped/pea-15 repression may contribute to rosiglitazone action on glucose disposal. Indeed, high fat diet mice showed insulin resistance and increased ped/pea-15 levels, although these effects were reduced by rosiglitazone treatment. Both supershift and ChIP assays revealed the presence of the AP-1 component c-JUN at the PED/PEA-15 promoter upon 12-O-tetradecanoylphorbol-13-acetate stimulation of the cells. In these experiments, rosiglitazone treatment reduced c-JUN presence at the PED/PEA-15 promoter. This effect was not associated with a decrease in c-JUN expression. In addition, c-jun silencing in L6 cells lowered ped/pea-15 expression and caused nonresponsiveness to rosiglitazone, although c-jun overexpression enhanced the binding to the ped/pea-15 promoter and blocked the rosiglitazone effect. These results indicate that PPARγ regulates ped/pea-15 transcription by inhibiting c-JUN binding at the ped/pea-15 promoter. Thus, ped/pea-15 is downstream of a major PPARγ-regulated inflammatory network. Repression of ped/pea-15 transcription might contribute to the PPARγ regulation of muscle sensitivity to insulin.

  9. Injected matrix stimulates myogenesis and regeneration of mouse skeletal muscle after ischaemic injury.

    PubMed

    Kuraitis, D; Ebadi, D; Zhang, P; Rizzuto, E; Vulesevic, B; Padavan, D T; Al Madhoun, A; McEwan, K A; Sofrenovic, T; Nicholson, K; Whitman, S C; Mesana, T G; Skerjanc, I S; Musarò, A; Ruel, M; Suuronen, E J

    2012-09-12

    Biomaterial-guided regeneration represents a novel approach for the treatment of myopathies. Revascularisation and the intramuscular extracellular matrix are important factors in stimulating myogenesis and regenerating muscle damaged by ischaemia. In this study, we used an injectable collagen matrix, enhanced with sialyl LewisX (sLeX), to guide skeletal muscle differentiation and regeneration. The elastic properties of collagen and sLeX-collagen matrices were similar to those of skeletal muscle, and culture of pluripotent mESCs on the matrices promoted their differentiation into myocyte-like cells expressing Pax3, MHC3, myogenin and Myf5. The regenerative properties of matrices were evaluated in ischaemic mouse hind-limbs. Treatment with the sLeX-matrix augmented the production of myogenic-mediated factors insulin-like growth factor (IGF)-1, and IGF binding protein-2 and -5 after 3 days. This was followed by muscle regeneration, including a greater number of regenerating myofibres and increased transcription of Six1, M-cadherin, myogenin and Myf5 after 10 days. Simultaneously, the sLeX-matrix promoted increased mobilisation and engraftment of bone marrow-derived progenitor cells, the development of larger arterioles and the restoration of tissue perfusion. Both matrix treatments tended to reduce maximal forces of ischaemic solei muscles, but sLeX-matrix lessened this loss of force and also prevented muscle fatigue. Only sLeX-matrix treatment improved mobility of mice on a treadmill. Together, these results suggest a novel approach for regenerative myogenesis, whereby treatment only with a matrix, which possesses an inherent ability to guide myogenic differentiation of pluripotent stem cells, can enhance the endogenous vascular and myogenic regeneration of skeletal muscle, thus holding promise for future clinical use.

  10. Chronic electrical stimulation drives mitochondrial biogenesis in skeletal muscle of a lizard, Varanus exanthematicus.

    PubMed

    Schaeffer, Paul J; Nichols, Scott D; Lindstedt, Stan L

    2007-10-01

    We investigated the capacity for phenotypic plasticity of skeletal muscle from Varanus exanthematicus, the savannah monitor lizard. Iliofibularis muscle from one leg of each lizard was electrically stimulated for 8 weeks. Both stimulated and contralateral control muscles were collected and processed for electron microscopy. We used stereological analysis of muscle cross-sections to quantify the volume densities of contractile elements, sarcoplasmic reticulum, mitochondria and intracellular lipids. We found that mitochondrial volume density was approximately fourfold higher in the stimulated muscle compared to controls, which were similar to previously reported values. Sarcoplasmic reticulum volume density was reduced by an amount similar to the increase in mitochondrial volume density while the volume density of contractile elements remained unchanged. Intracellular lipid accumulation was visibly apparent in many stimulated muscle sections but the volume density of lipids did not reach a significant difference. Although monitor lizards lack the highly developed aerobic metabolism of mammals, they appear to possess the capacity for muscle plasticity.

  11. The effects of pre-exercise vibration stimulation on the exercise-induced muscle damage

    PubMed Central

    Kim, Ji-Yun; Kang, Da-Haeng; Lee, Joon-Hee; O, Se-Min; Jeon, Jae-Keun

    2017-01-01

    [Purpose] To investigate the effects of pre-induced muscle damage vibration stimulation on the pressure-pain threshold and muscle-fatigue-related metabolites of exercise-induced muscle damage. [Subjects and Methods] Thirty healthy, adult male subjects were randomly assigned to the pre-induced muscle damage vibration stimulation group, post-induced muscle damage vibration stimulation group, or control group (n=10 per group). To investigate the effects of pre-induced muscle damage vibration stimulation, changes in the pressure-pain threshold (lb), creatine kinase level (U/L), and lactate dehydrogenase level (U/L) were measured and analyzed at baseline and at 24 hours, 48 hours, and 72 hours after exercise. [Results] The pressure-pain thresholds and concentrations of creatine kinase and lactate dehydrogenase varied significantly in each group and during each measurement period. There were interactions between the measurement periods and groups, and results of the post-hoc test showed that the pre-induced muscle damage vibration stimulation group had the highest efficacy among the groups. [Conclusion] Pre-induced muscle damage vibration stimulation is more effective than post-induced muscle damage vibration stimulation for preventing muscle damage. PMID:28210056

  12. E-ring 8-isoprostanes are agonists at EP2- and EP4-prostanoid receptors on human airway smooth muscle cells and regulate the release of colony-stimulating factors by activating cAMP-dependent protein kinase.

    PubMed

    Clarke, Deborah L; Belvisi, Maria G; Hardaker, Elizabeth; Newton, Robert; Giembycz, Mark A

    2005-02-01

    8-Isoprostanes are bioactive lipid mediators formed via the nonenzymatic peroxidation of arachidonic acid by free radicals and reactive oxygen species. However, their cognate receptors, biological actions, and signaling pathways are poorly studied. Here, we report the effect of a variety of E- and Falpha-ring 8-isoprostanes on the release of granulocyte/macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) from human airway smooth muscle (HASM) cells stimulated with interleukin-1beta (IL-1beta). The elaboration of GM-CSF and G-CSF by IL-1beta was inhibited and augmented, respectively, in a concentration-dependent manner by 8-iso-prostaglandin (PG) E(1) and 8-iso-PGE(2), but not by 8-iso-PGF(1alpha), 8-iso-PGF(2alpha), and 8-iso-PGF(3)alpha. AH 6809 (6-isopropoxy-9-oxoxanthine-2-carboxylic acid), an EP(1)-/EP(2)-/DP-receptor blocking drug, antagonized the inhibitory effect of 8-iso-PGE(1) and 8-iso-PGE(2) on GM-CSF output with an affinity consistent with an interaction at prostanoid receptors of the EP(2)-subtype. In contrast, the facilitation by 8-iso-PGE(1) and 8-iso-PGE(2) of G-CSF release was unaffected by AH 6809 and the selective EP(4)-receptor antagonist L-161,982 [4'-[3-butyl-5-oxo-1-(2-trifluoromethyl-phenyl)-1,5-dihydro-[1,2,4]triazol-4-ylmethyl]-biphenyl-2-sulfonic acid (3-methyl-thiophene-2-carbonyl)-amide]. However, when used in combination, AH 6809 and L-161,982 displaced 5-fold to the right the 8-iso-PGE and 8-iso-PGE concentration-response curves. The opposing (1)effect of E-ring (2)8-isoprostanes on GM-CSF and G-CSF release was mimicked by 8-bromo-cAMP and abolished in cells infected with an adenovirus vector encoding an inhibitor protein of cAMP-dependent protein kinase (PKA). Together, these data demonstrate that E-ring 8-isoprostanes regulate the secretion of GM-CSF and G-CSF from HASM cells by a cAMP- and PKA-dependent mechanism. Moreover, antagonist studies revealed that 8-iso-PGE(1) and 8-iso-PGE(2

  13. The Effect of Mechanical Vibration Stimulation of Perception Subthreshold on the Muscle Force and Muscle Reaction Time of Lower Leg

    PubMed Central

    Kim, Huigyun; Kwak, Kiyoung; Kim, Dongwook

    2016-01-01

    The objective of this study is to investigate the effect of mechanical vibration stimulation on the muscle force and muscle reaction time of lower leg according to perception threshold and vibration frequency. A vibration stimulation with perception threshold intensity was applied on the Achilles tendon and tibialis anterior tendon. EMG measurement and analysis system were used to analyze the change of muscle force and muscle reaction time according to perception threshold and vibration frequency. A root-mean-square (RMS) value was extracted using analysis software and Maximum Voluntary Contraction (MVC) and Premotor Time (PMT) were analyzed. The measurement results showed that perception threshold was different from application sites of vibration frequency. Also, the muscle force and muscle reaction time showed difference according to the presence of vibration, frequency, and intensity. This result means that the vibration stimulation causes the change on the muscle force and muscle reaction time and affects the muscles of lower leg by the characteristics of vibration stimulation. PMID:27382244

  14. Chronic Stimulation-Induced Changes in the Rodent Thyroarytenoid Muscle

    ERIC Educational Resources Information Center

    McMullen, Colleen A.; Butterfield, Timothy A.; Dietrich, Maria; Andreatta, Richard D.; Andrade, Francisco H.; Fry, Lisa; Stemple, Joseph C.

    2011-01-01

    Purpose: Therapies for certain voice disorders purport principles of skeletal muscle rehabilitation to increase muscle mass, strength, and endurance. However, applicability of limb muscle rehabilitation to the laryngeal muscles has not been tested. In this study, the authors examined the feasibility of the rat thyroarytenoid muscle to remodel as a…

  15. Skeletal Muscle Cell Behavior After Physical Agent Treatments.

    PubMed

    Battistelli, Michela; Salucci, Sara; Guescini, Michele; Curzi, Davide; Stocchi, Vilberto; Falcieri, Elisabetta

    2015-01-01

    causing muscle cell damage or death too. Finally, hypothermia, stimulating the autophagic response, could have a key role in muscle injury prevention.

  16. Mechanical stimulation of skeletal muscle generates lipid-related second messengers by phospholipase activation

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H. H.; Shansky, J.; Karlisch, P.; Solerssi, R. L.

    1993-01-01

    Repetitive mechanical stimulation of cultured avian skeletal muscle increases the synthesis of prostaglandins (PG) E2 and F2 alpha which regulate protein turnover rates and muscle cell growth. These stretch-induced PG increases are reduced in low extracellular calcium medium and by specific phospholipase inhibitors. Mechanical stimulation increases the breakdown rate of 3H-arachidonic acid labelled phospholipids, releasing free 3H-arachidonic acid, the rate-limiting precursor of PG synthesis. Mechanical stimulation also increases 3H-arachidonic acid labelled diacylglycerol formation and intracellular levels of inositol phosphates from myo-[2-3H]inositol labelled phospholipids. Phospholipase A2 (PLA2), phosphatidylinositol-specific phospholipase C (PLC), and phospholipase D (PLD) are all activated by stretch. The stretch-induced increases in PG production, 3H-arachidonic acid labelled phospholipid breakdown, and 3H-arachidonic acid labelled diacylglycerol formation occur independently of cellular electrical activity (tetrodotoxin insensitive) whereas the formation of inositol phosphates from myo-[2-3H]inositol labelled phospholipids is dependent on cellular electrical activity. These results indicate that mechanical stimulation increases the lipid-related second messengers arachidonic acid, diacylglycerol, and PG through activation of specific phospholipases such as PLA2 and PLD, but not by activation of phosphatidylinositol-specific PLC.

  17. Mechanical stimulation of skeletal muscle generates lipid-related second messengers by phospholipase activation

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.; Shansky, Janet; Karlisch, Patricia; Solerssi, Rosa Lopez

    1991-01-01

    Repetitive mechanical stimulation of cultured avian skeletal muscle increases the synthesis of prostaglandins E2 and F2(alpha) which regulate protein turnover rates and muscle cell growth. Mechnical stimulation significantly increases the breakdown rate of (3)H-arachidonic acid labelled phospholipids, releasing free (3)H-arachidonic acid, and the rate-limiting precursor of prostaglandin synthesis. Mechanical stimulation also significantly increases (3)H-arachidonic acid labelled diacylglycerol formation and intracellular levels of inositol phosphates from myo-2-(3)H inositol labelled phospholipids. Phospholipase A2, phosphatidylinositol-specific phospholipase C (PLC), and phospholipase D (PLD) are activated by stretch. The lipase inhibitors bromophenacylbromide and RHC80267 together reduce stretch-induced prostaglandin production by 73-83 percent. The stretch-induced increases in prostaglandin production, (3)H-arachidonic acid labelled phospholipid breakdown, and (3)H-arachidonic acid labelled diacylglycerol formation occur independently of cellular electrical activity (tetrodotoxin insensitive) whereas the formation of inositol phosphates from myo-2-(3)H inositol labelled phospholipids are dependent on cellular electrical activity. These results indicate that mechanical stimulation increases the lipid-related second messengers arachidonic acid, diacylglycerol, and prostaglandins through activation of specific phospholipases such as PLA2 and PLD, but not by activation of phosphatidylinositol-specific PLC.

  18. MEAT SCIENCE AND MUSCLE BIOLOGY SYMPOSIUM--mechanism of growth hormone stimulation of skeletal muscle growth in cattle.

    PubMed

    Jiang, H; Ge, X

    2014-01-01

    Growth hormone, also called somatotropin (ST), is a polypeptide hormone produced by the anterior pituitary. The major functions of GH include stimulating bone and skeletal muscle growth, lipolysis, milk production, and expression of the IGF-I gene in the liver. Based on these functions, recombinant bovine ST (bST) and recombinant porcine ST (pST) have been used to improve milk production in dairy cows and lean tissue growth in pigs, respectively. However, despite these applications, the mechanisms of action of GH are not fully understood. Indeed, there has been a lot of controversy over the role of liver-derived circulating IGF-I and locally produced IGF-I in mediating the growth-stimulatory effect of GH during the last 15 yr. It is in this context that we have conducted studies to further understand how GH stimulates skeletal muscle growth in cattle. Our results do not support a role of skeletal muscle-derived IGF-I in GH-stimulated skeletal muscle growth in cattle. Our results indicate that GH stimulates skeletal muscle growth in cattle, in part, by stimulating protein synthesis in muscle through a GH receptor-mediated, IGF-I-independent mechanism. In this review, besides discussing these results, we also argue that liver-derived circulating IGF-I should be still considered as the major mechanism that mediates the growth-stimulatory effect of GH on skeletal muscle in cattle and other domestic animals.

  19. Effects of electrical stimulation on histochemical muscle fiber staining, quality, and composition of camel and cattle Longissimus thoracis muscles.

    PubMed

    Kadim, I T; Mahgoub, O; Al-Marzooqi, W; Khalaf, S K; Mansour, M H; Al-Sinani, S S H; Al-Amri, I S

    2009-01-01

    The effects of electrical stimulation on muscle fiber type, meat quality, and composition of Longissimus thoracis muscles from one-humped camels and Dofari Omani cattle of a comparable age range were investigated. A low-voltage electrical stimulation with 90 V, 14 Hz (pulse of 7.5-millisecond duration every 70 milliseconds) 20 min postmortem was applied. Samples from the left muscle were collected from 20 (2 to 3 y) camels and 24 cattle (1 to 3 y). For chemical composition, muscle samples were dried in a freeze dryer, and then ground to determine moisture, protein, fat, and ash. Macro- and micro-minerals were determined using an Inductively Coupled Plasma Emission Spectrometer. Quality characteristics of the meat were evaluated using shear force value, pH, sarcomere, myofibrillar fragmentation index, expressed juice, cooking loss percent, and CIE L*, a*, b* color values. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in the muscle during the first 24 h after slaughter in both species. Muscles from electrically stimulated carcasses had significantly (P < 0.05) lower ultimate pH, longer sarcomere, and lower shear force values than those from nonstimulated carcasses. Lightness (L*), myofibrillar fragmentation, and expressed juice were significantly (P < 0.05) higher for stimulated than for nonstimulated muscles. Muscles of camels had significantly (P < 0.05) higher expressed juice, cooking loss percent, redness color (a*), and lower fat, Mg, K, and P than those from cattle. Electrical stimulation improved quality characteristics of meat from both species. This indicates that meat quality of local camel and cattle can be improved by electrical stimulation and consequently improves their acceptability to consumers and better marketability.

  20. Muscle motor point identification is essential for optimizing neuromuscular electrical stimulation use.

    PubMed

    Gobbo, Massimiliano; Maffiuletti, Nicola A; Orizio, Claudio; Minetto, Marco A

    2014-02-25

    Transcutaneous neuromuscular electrical stimulation applied in clinical settings is currently characterized by a wide heterogeneity of stimulation protocols and modalities. Practitioners usually refer to anatomic charts (often provided with the user manuals of commercially available stimulators) for electrode positioning, which may lead to inconsistent outcomes, poor tolerance by the patients, and adverse reactions. Recent evidence has highlighted the crucial importance of stimulating over the muscle motor points to improve the effectiveness of neuromuscular electrical stimulation. Nevertheless, the correct electrophysiological definition of muscle motor point and its practical significance are not always fully comprehended by therapists and researchers in the field. The commentary describes a straightforward and quick electrophysiological procedure for muscle motor point identification. It consists in muscle surface mapping by using a stimulation pen-electrode and it is aimed at identifying the skin area above the muscle where the motor threshold is the lowest for a given electrical input, that is the skin area most responsive to electrical stimulation. After the motor point mapping procedure, a proper placement of the stimulation electrode(s) allows neuromuscular electrical stimulation to maximize the evoked tension, while minimizing the dose of the injected current and the level of discomfort. If routinely applied, we expect this procedure to improve both stimulation effectiveness and patient adherence to the treatment.The aims of this clinical commentary are to present an optimized procedure for the application of neuromuscular electrical stimulation and to highlight the clinical implications related to its use.

  1. Oral Gingival Cell Cigarette Smoke Exposure Induces Muscle Cell Metabolic Disruption

    PubMed Central

    Baeder, Andrea C.; Napa, Kiran; Richardson, Sarah T.; Taylor, Oliver J.; Andersen, Samantha G.; Wilcox, Shalene H.; Winden, Duane R.; Reynolds, Paul R.

    2016-01-01

    Cigarette smoke exposure compromises health through damaging multiple physiological systems, including disrupting metabolic function. The purpose of this study was to determine the role of oral gingiva in mediating the deleterious metabolic effects of cigarette smoke exposure on skeletal muscle metabolic function. Using an in vitro conditioned medium cell model, skeletal muscle cells were incubated with medium from gingival cells treated with normal medium or medium containing suspended cigarette smoke extract (CSE). Following incubation of muscle cells with gingival cell conditioned medium, muscle cell mitochondrial respiration and insulin signaling and action were determined as an indication of overall muscle metabolic health. Skeletal muscle cells incubated with conditioned medium of CSE-treated gingival cells had a profound reduction in mitochondrial respiration and respiratory control. Furthermore, skeletal muscle cells had a greatly reduced response in insulin-stimulated Akt phosphorylation and glycogen synthesis. Altogether, these results provide a novel perspective on the mechanism whereby cigarette smoke affects systemic metabolic function. In conclusion, we found that oral gingival cells treated with CSE create an altered milieu that is sufficient to both disrupted skeletal muscle cell mitochondrial function and insulin sensitivity. PMID:27034671

  2. Oral Gingival Cell Cigarette Smoke Exposure Induces Muscle Cell Metabolic Disruption.

    PubMed

    Baeder, Andrea C; Napa, Kiran; Richardson, Sarah T; Taylor, Oliver J; Andersen, Samantha G; Wilcox, Shalene H; Winden, Duane R; Reynolds, Paul R; Bikman, Benjamin T

    2016-01-01

    Cigarette smoke exposure compromises health through damaging multiple physiological systems, including disrupting metabolic function. The purpose of this study was to determine the role of oral gingiva in mediating the deleterious metabolic effects of cigarette smoke exposure on skeletal muscle metabolic function. Using an in vitro conditioned medium cell model, skeletal muscle cells were incubated with medium from gingival cells treated with normal medium or medium containing suspended cigarette smoke extract (CSE). Following incubation of muscle cells with gingival cell conditioned medium, muscle cell mitochondrial respiration and insulin signaling and action were determined as an indication of overall muscle metabolic health. Skeletal muscle cells incubated with conditioned medium of CSE-treated gingival cells had a profound reduction in mitochondrial respiration and respiratory control. Furthermore, skeletal muscle cells had a greatly reduced response in insulin-stimulated Akt phosphorylation and glycogen synthesis. Altogether, these results provide a novel perspective on the mechanism whereby cigarette smoke affects systemic metabolic function. In conclusion, we found that oral gingival cells treated with CSE create an altered milieu that is sufficient to both disrupted skeletal muscle cell mitochondrial function and insulin sensitivity.

  3. Electrical stimulation partly reverses the muscle insulin resistance caused by tenotomy.

    PubMed

    Langfort, J; Czarnowski, D; Budohoski, L; Górski, J; Kaciuba-Uściłko, H; Nazar, K

    1993-01-04

    It was shown that 15-min electrical stimulation of the rat sciatic nerve greatly increases the in vitro measured sensitivity of lactate formation, glucose transport, and glycogen synthesis to insulin, impaired by previous tenotomy. The insulin sensitivity of all these processes was, however, still below that found in the stimulated intact soleus muscle. Extending the stimulation up to 30 min did not cause any further changes in insulin sensitivity either in tenotomized or in intact muscles.

  4. Intestinal smooth muscle cell maintenance by basic fibroblast growth factor.

    PubMed

    Lee, Min; Wu, Benjamin M; Stelzner, Matthias; Reichardt, Holger M; Dunn, James C Y

    2008-08-01

    Intestinal tissue engineering is a potential therapy for patients with short bowel syndrome. Tissue engineering scaffolds that promote smooth muscle cell proliferation and angiogenesis are essential toward the regeneration of functional smooth muscles for peristalsis and motility. Since basic fibroblast growth factor (bFGF) can stimulate smooth muscle proliferation and angiogenesis, the delivery of bFGF was employed to stimulate proliferation and survival of primary intestinal smooth muscle cells. Two methods of local bFGF delivery were examined: the incorporation of bFGF into the collagen coating and the encapsulation of bFGF into poly(D,L-lactic-co-glycolic acid) microspheres. Cell-seeded scaffolds were implanted into the omentum and were retrieved after 4, 14, and 28 days. The seeded cells proliferated from day 4 to day 14 in all implants; however, at 28 days, significantly higher density of implanted cells and blood vessels was observed, when 10 microg of bFGF was incorporated into the collagen coating of scaffolds as compared to scaffolds with either no bFGF or 1 microg of bFGF in collagen. Microsphere encapsulation of 1 microg of bFGF produced similar effects as 10 microg of bFGF mixed in collagen and was more effective than the delivery of 1 microg of bFGF by collagen incorporation. The majority of the implanted cells also expressed alpha-smooth muscle actin. Scaffolds coated with microsphere-encapsulated bFGF and seeded with smooth muscle cells may be a useful platform for the regeneration of the intestinal smooth muscle.

  5. Rac1 is a novel regulator of contraction-stimulated glucose uptake in skeletal muscle.

    PubMed

    Sylow, Lykke; Jensen, Thomas E; Kleinert, Maximilian; Mouatt, Joshua R; Maarbjerg, Stine J; Jeppesen, Jacob; Prats, Clara; Chiu, Tim T; Boguslavsky, Shlomit; Klip, Amira; Schjerling, Peter; Richter, Erik A

    2013-04-01

    In skeletal muscle, the actin cytoskeleton-regulating GTPase, Rac1, is necessary for insulin-dependent GLUT4 translocation. Muscle contraction increases glucose transport and represents an alternative signaling pathway to insulin. Whether Rac1 is activated by muscle contraction and regulates contraction-induced glucose uptake is unknown. Therefore, we studied the effects of in vivo exercise and ex vivo muscle contractions on Rac1 signaling and its regulatory role in glucose uptake in mice and humans. Muscle Rac1-GTP binding was increased after exercise in mice (~60-100%) and humans (~40%), and this activation was AMP-activated protein kinase independent. Rac1 inhibition reduced contraction-stimulated glucose uptake in mouse muscle by 55% in soleus and by 20-58% in extensor digitorum longus (EDL; P < 0.01). In agreement, the contraction-stimulated increment in glucose uptake was decreased by 27% (P = 0.1) and 40% (P < 0.05) in soleus and EDL muscles, respectively, of muscle-specific inducible Rac1 knockout mice. Furthermore, depolymerization of the actin cytoskeleton decreased contraction-stimulated glucose uptake by 100% and 62% (P < 0.01) in soleus and EDL muscles, respectively. These are the first data to show that Rac1 is activated during muscle contraction in murine and human skeletal muscle and suggest that Rac1 and possibly the actin cytoskeleton are novel regulators of contraction-stimulated glucose uptake.

  6. Insulin-independent, MAPK-dependent stimulation of NKCC activity in skeletal muscle.

    PubMed

    Wong, J A; Gosmanov, A R; Schneider, E G; Thomason, D B

    2001-08-01

    Na(+)-K(+)-Cl(-) cotransporter (NKCC) activity in quiescent skeletal muscle is modest. However, ex vivo stimulation of muscle for as little as 18 contractions (1 min, 0.3 Hz) dramatically increased the activity of the cotransporter, measured as the bumetanide-sensitive (86)Rb influx, in both soleus and plantaris muscles. This activation of cotransporter activity remained relatively constant for up to 10-Hz stimulation for 1 min, falling off at higher frequencies (30-Hz stimulation for 1 min). Similarly, stimulation of skeletal muscle with adrenergic receptor agonists phenylephrine, isoproterenol, or epinephrine produced a dramatic stimulation of NKCC activity. It did not appear that stimulation of NKCC activity was a reflection of increased Na(+)-K(+)-ATPase activity because insulin treatment did not stimulate NKCC activity, despite insulin's well-known stimulation of Na(+)-K(+)-ATPase activity. Stimulation of NKCC activity could be blocked by pretreatment with inhibitors of mitogen-activated protein kinase (MAPK) kinase 1/2 (MEK1/2) activity, indicating that activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) MAPKs may be required. These data indicate a regulated NKCC activity in skeletal muscle that may provide a significant pathway for potassium transport into skeletal muscle fibers.

  7. Bone Marrow Stromal Cells Generate Muscle Cells and Repair Muscle Degeneration

    NASA Astrophysics Data System (ADS)

    Dezawa, Mari; Ishikawa, Hiroto; Itokazu, Yutaka; Yoshihara, Tomoyuki; Hoshino, Mikio; Takeda, Shin-ichi; Ide, Chizuka; Nabeshima, Yo-ichi

    2005-07-01

    Bone marrow stromal cells (MSCs) have great potential as therapeutic agents. We report a method for inducing skeletal muscle lineage cells from human and rat general adherent MSCs with an efficiency of 89%. Induced cells differentiated into muscle fibers upon transplantation into degenerated muscles of rats and mdx-nude mice. The induced population contained Pax7-positive cells that contributed to subsequent regeneration of muscle upon repetitive damage without additional transplantation of cells. These MSCs represent a more ready supply of myogenic cells than do the rare myogenic stem cells normally found in muscle and bone marrow.

  8. Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort.

    PubMed

    Nakano, Sota; Wada, Chikamune

    2016-05-01

    [Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8-89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata.

  9. Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort

    PubMed Central

    Nakano, Sota; Wada, Chikamune

    2016-01-01

    [Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8–89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata. PMID:27313387

  10. Concept Developed for an Implanted Stimulated Muscle-Powered Piezoelectric Generator

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth; Kilgore, Kevin; Ercegovic, David; Gustafson, Kenneth

    2005-01-01

    Implanted electronic devices are typically powered by batteries or transcutaneous power transmission. Batteries must be replaced or recharged, and transcutaneous power sources burden the patient or subject with external equipment prone to failure. A completely self-sustaining implanted power source would alleviate these limitations. Skeletal muscle provides an available autologous power source containing native chemical energy that produces power in excess of the requirements for muscle activation by motor nerve stimulation. A concept has been developed to convert stimulated skeletal muscle power into electrical energy (see the preceding illustration). We propose to connect a piezoelectric generator between a muscle tendon and bone. Electrically stimulated muscle contractions would exert force on the piezoelectric generator, charging a storage circuit that would be used to power the stimulator and other devices.

  11. Overexpression of follistatin in trout stimulates increased muscling.

    PubMed

    Medeiros, Erika F; Phelps, Michael P; Fuentes, Fernando D; Bradley, Terence M

    2009-07-01

    Deletion or inhibition of myostatin in mammals has been demonstrated to markedly increase muscle mass by hyperplasia, hypertrophy, or a combination of both. Despite a remarkably high degree of conservation with the mammalian protein, the function of myostatin remains unknown in fish, many species of which continue muscle growth throughout the lifecycle by hyperplasia. Transgenic rainbow trout (Oncorhynchus mykiss) overexpressing follistatin, one of the more efficacious antagonists of myostatin, were produced to investigate the effect of this protein on muscle development and growth. P(1) transgenics overexpressing follistatin in muscle tissue exhibited increased epaxial and hypaxial muscling similar to that observed in double-muscled cattle and myostatin null mice. The hypaxial muscling generated a phenotype reminiscent of well-developed rectus abdominus and intercostal muscles in humans and was dubbed "six pack." Body conformation of the transgenic animals was markedly altered, as measured by condition factor, and total muscle surface area increased. The increased muscling was due almost exclusively to hyperplasia as evidenced by a higher number of fibers per unit area and increases in the percentage of smaller fibers and the number of total fibers. In several individuals, asymmetrical muscling was observed, but no changes in mobility or behavior of follistatin fish were observed. The findings indicate that overexpression of follistatin in trout, a species with indeterminate growth rate, enhances muscle growth. It remains to be determined whether the double muscling in trout is due to inhibition of myostatin, other growth factors, or both.

  12. Interstitial cells: regulators of smooth muscle function.

    PubMed

    Sanders, Kenton M; Ward, Sean M; Koh, Sang Don

    2014-07-01

    Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα(+) cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα(+) cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.

  13. Interstitial Cells: Regulators of Smooth Muscle Function

    PubMed Central

    Sanders, Kenton M.; Ward, Sean M.; Koh, Sang Don

    2014-01-01

    Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα+ cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα+ cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues. PMID:24987007

  14. Regulatory T cells and skeletal muscle regeneration.

    PubMed

    Schiaffino, Stefano; Pereira, Marcelo G; Ciciliot, Stefano; Rovere-Querini, Patrizia

    2017-02-01

    Skeletal muscle regeneration results from the activation and differentiation of myogenic stem cells, called satellite cells, located beneath the basal lamina of the muscle fibers. Inflammatory and immune cells have a crucial role in the regeneration process. Acute muscle injury causes an immediate transient wave of neutrophils followed by a more persistent infiltration of M1 (proinflammatory) and M2 (anti-inflammatory/proregenerative) macrophages. New studies show that injured muscle is also infiltrated by a specialized population of regulatory T (Treg) cells, which control both the inflammatory response, by promoting the M1-to-M2 switch, and the activation of satellite cells. Treg cells accumulate in injured muscle in response to specific cytokines, such as IL-33, and promote muscle growth by releasing growth factors, such as amphiregulin. Muscle repair during aging is impaired due to reduced number of Treg cells and can be enhanced by IL-33 supplementation. Migration of Treg cells could also contribute to explain the effect of heterochronic parabiosis, whereby muscle regeneration of aged mice can be improved by a parabiotically linked young partners. In mdx dystrophin-deficient mice, a model of human Duchenne muscular dystrophy, muscle injury, and inflammation is mitigated by expansion of the Treg-cell population but exacerbated by Treg-cell depletion. These findings support the notion that immunological mechanisms are not only essential in the response to pathogenic microbes and tumor cells but also have a wider homeostatic role in tissue repair, and open new perspectives for boosting muscle growth in chronic muscle disease and during aging.

  15. The TMS Map Scales with Increased Stimulation Intensity and Muscle Activation.

    PubMed

    van de Ruit, Mark; Grey, Michael J

    2016-01-01

    One way to study cortical organisation, or its reorganisation, is to use transcranial magnetic stimulation (TMS) to construct a map of corticospinal excitability. TMS maps are reported to be acquired with a wide variety of stimulation intensities and levels of muscle activation. Whilst MEPs are known to increase both with stimulation intensity and muscle activation, it remains to be established what the effect of these factors is on the map's centre of gravity (COG), area, volume and shape. Therefore, the objective of this study was to systematically examine the effect of stimulation intensity and muscle activation on these four key map outcome measures. In a first experiment, maps were acquired with a stimulation intensity of 110, 120 and 130% of resting threshold. In a second experiment, maps were acquired at rest and at 5, 10, 20 and 40% of maximum voluntary contraction. Map area and map volume increased with both stimulation intensity (P < 0.01) and muscle activation (P < 0.01). Neither the COG nor the map shape changed with either stimulation intensity or muscle activation (P > 0.09 in all cases). This result indicates the map simply scales with stimulation intensity and muscle activation.

  16. Responses of muscle spindles in feline dorsal neck muscles to electrical stimulation of the cervical sympathetic nerve.

    PubMed

    Hellström, F; Roatta, S; Thunberg, J; Passatore, M; Djupsjöbacka, M

    2005-09-01

    Previous studies performed in jaw muscles of rabbits and rats have demonstrated that sympathetic outflow may affect the activity of muscle spindle afferents (MSAs). The resulting impairment of MSA information has been suggested to be involved in the genesis and spread of chronic muscle pain. The present study was designed to investigate sympathetic influences on muscle spindles in feline trapezius and splenius muscles (TrSp), as these muscles are commonly affected by chronic pain in humans. Experiments were carried out in cats anesthetized with alpha-chloralose. The effect of electrical stimulation (10 Hz for 90 s or 3 Hz for 5 min) of the peripheral stump of the cervical sympathetic nerve (CSN) was investigated on the discharge of TrSp MSAs (units classified as Ia-like and II-like) and on their responses to sinusoidal stretching of these muscles. In some of the experiments, the local microcirculation of the muscles was monitored by laser Doppler flowmetry. In total, 46 MSAs were recorded. Stimulation of the CSN at 10 Hz powerfully depressed the mean discharge rate of the majority of the tested MSAs (73%) and also affected the sensitivity of MSAs to sinusoidal changes of muscle length, which were evaluated in terms of amplitude and phase of the sinusoidal fitting of unitary activity. The amplitude was significantly reduced in Ia-like units and variably affected in II-like units, while in general the phase was affected little and not changed significantly in either group. The discharge of a smaller percentage of tested units was also modulated by 3-Hz CSN stimulation. Blockade of the neuromuscular junctions by pancuronium did not induce any changes in MSA responses to CSN stimulation, showing that these responses were not secondary to changes in extrafusal or fusimotor activity. Further data showed that the sympathetically induced modulation of MSA discharge was not secondary to the concomitant reduction of muscle blood flow induced by the stimulation. Hence

  17. The influence of antagonist muscle electrical stimulation on maximal hip adduction force

    PubMed Central

    Nakano, Sota; Wada, Chikamune

    2016-01-01

    [Purpose] The aim of this study was to determine whether electrical stimulation of the tensor fascia lata muscle decreases voluntary maximum resistance to passive abduction motion in participants without disease of the central nervous system. [Subjects] The participants were 16 healthy men. [Methods] The hip joint was moved from 10° adduction to 0° adduction with an angular velocity of 7°/s. During the passive leg motion, the subject was asked to resist the motion with maximum force. Two experimental conditions were prepared: (1) electrical stimulation provided to the tensor fascia lata muscle during the passive motion; and (2) no electrical stimulation provided. [Results] The force was 10.2 ± 3.5 kgf with electrical stimulation and 12.2 ± 3.8 kgf without electrical stimulation. [Conclusion] The results suggested that the maximum hip adduction force decreased in participants because of electrical stimulation of the tensor fascia lata muscle. PMID:26957742

  18. Enhanced Cultivation Of Stimulated Murine B Cells

    NASA Technical Reports Server (NTRS)

    Sammons, David W.

    1994-01-01

    Method of in vitro cultivation of large numbers of stimulated murine B lymphocytes. Cells electrofused with other cells to produce hybridomas and monoclonal antibodies. Offers several advantages: polyclonally stimulated B-cell blasts cultivated for as long as 14 days, hybridomas created throughout culture period, yield of hybridomas increases during cultivation, and possible to expand polyclonally in vitro number of B cells specific for antigenic determinants first recognized in vivo.

  19. Smooth Muscle Enriched Long Noncoding RNA (SMILR) Regulates Cell Proliferation

    PubMed Central

    Ballantyne, Margaret D.; Pinel, Karine; Dakin, Rachel; Vesey, Alex T.; Diver, Louise; Mackenzie, Ruth; Garcia, Raquel; Welsh, Paul; Sattar, Naveed; Hamilton, Graham; Joshi, Nikhil; Dweck, Marc R.; Miano, Joseph M.; McBride, Martin W.; Newby, David E.; McDonald, Robert A.

    2016-01-01

    Background— Phenotypic switching of vascular smooth muscle cells from a contractile to a synthetic state is implicated in diverse vascular pathologies, including atherogenesis, plaque stabilization, and neointimal hyperplasia. However, very little is known about the role of long noncoding RNA (lncRNA) during this process. Here, we investigated a role for lncRNAs in vascular smooth muscle cell biology and pathology. Methods and Results— Using RNA sequencing, we identified >300 lncRNAs whose expression was altered in human saphenous vein vascular smooth muscle cells following stimulation with interleukin-1α and platelet-derived growth factor. We focused on a novel lncRNA (Ensembl: RP11-94A24.1), which we termed smooth muscle–induced lncRNA enhances replication (SMILR). Following stimulation, SMILR expression was increased in both the nucleus and cytoplasm, and was detected in conditioned media. Furthermore, knockdown of SMILR markedly reduced cell proliferation. Mechanistically, we noted that expression of genes proximal to SMILR was also altered by interleukin-1α/platelet-derived growth factor treatment, and HAS2 expression was reduced by SMILR knockdown. In human samples, we observed increased expression of SMILR in unstable atherosclerotic plaques and detected increased levels in plasma from patients with high plasma C-reactive protein. Conclusions— These results identify SMILR as a driver of vascular smooth muscle cell proliferation and suggest that modulation of SMILR may be a novel therapeutic strategy to reduce vascular pathologies. PMID:27052414

  20. Colonization of the satellite cell niche by skeletal muscle progenitor cells depends on Notch signals.

    PubMed

    Bröhl, Dominique; Vasyutina, Elena; Czajkowski, Maciej T; Griger, Joscha; Rassek, Claudia; Rahn, Hans-Peter; Purfürst, Bettina; Wende, Hagen; Birchmeier, Carmen

    2012-09-11

    Skeletal muscle growth and regeneration rely on myogenic progenitor and satellite cells, the stem cells of postnatal muscle. Elimination of Notch signals during mouse development results in premature differentiation of myogenic progenitors and formation of very small muscle groups. Here we show that this drastic effect is rescued by mutation of the muscle differentiation factor MyoD. However, rescued myogenic progenitors do not assume a satellite cell position and contribute poorly to myofiber growth. The disrupted homing is due to a deficit in basal lamina assembly around emerging satellite cells and to their impaired adhesion to myofibers. On a molecular level, emerging satellite cells deregulate the expression of basal lamina components and adhesion molecules like integrin α7, collagen XVIIIα1, Megf10, and Mcam. We conclude that Notch signals control homing of satellite cells, stimulating them to contribute to their own microenvironment and to adhere to myofibers.

  1. Satellite Cells and Skeletal Muscle Regeneration.

    PubMed

    Dumont, Nicolas A; Bentzinger, C Florian; Sincennes, Marie-Claude; Rudnicki, Michael A

    2015-07-01

    Skeletal muscles are essential for vital functions such as movement, postural support, breathing, and thermogenesis. Muscle tissue is largely composed of long, postmitotic multinucleated fibers. The life-long maintenance of muscle tissue is mediated by satellite cells, lying in close proximity to the muscle fibers. Muscle satellite cells are a heterogeneous population with a small subset of muscle stem cells, termed satellite stem cells. Under homeostatic conditions all satellite cells are poised for activation by stimuli such as physical trauma or growth signals. After activation, satellite stem cells undergo symmetric divisions to expand their number or asymmetric divisions to give rise to cohorts of committed satellite cells and thus progenitors. Myogenic progenitors proliferate, and eventually differentiate through fusion with each other or to damaged fibers to reconstitute fiber integrity and function. In the recent years, research has begun to unravel the intrinsic and extrinsic mechanisms controlling satellite cell behavior. Nonetheless, an understanding of the complex cellular and molecular interactions of satellite cells with their dynamic microenvironment remains a major challenge, especially in pathological conditions. The goal of this review is to comprehensively summarize the current knowledge on satellite cell characteristics, functions, and behavior in muscle regeneration and in pathological conditions.

  2. Immunohistochemical and Morphofunctional Studies of Skeletal Muscle Tissues with Electric Nerve Stimulation by In Vivo Cryotechnique

    PubMed Central

    Fukasawa, Yuki; Ohno, Nobuhiko; Saitoh, Yurika; Saigusa, Takeshi; Arita, Jun; Ohno, Shinichi

    2015-01-01

    In this study, morphological and immunohistochemical alterations of skeletal muscle tissues during persistent contraction were examined by in vivo cryotechnique (IVCT). Contraction of gastrocnemius muscles was induced by sciatic nerve stimulation. The IVCT was performed immediately, 3 min or 10 min after the stimulation start. Prominent ripples of muscle fibers or wavy deformation of sarcolemma were detected immediately after the stimulation, but they gradually diminished to normal levels during the stimulation. The relative ratio of sarcomere and A band lengths was the highest in the control group, but it immediately decreased to the lowest level and then gradually recovered at 3 min or 10 min. Although histochemical intensity of PAS reaction was almost homogeneous in muscle tissues of the control group or immediately after the stimulation, it decreased at 3 min or 10 min. Serum albumin was immunolocalized as dot-like patterns within some muscle fibers at 3 min stimulation. These patterns became more prominent at 10 min, and the dots got larger and saccular in some sarcoplasmic regions. However, IgG1 and IgM were immunolocalized in blood vessels under nerve stimulation conditions. Therefore, IVCT was useful to capture the morphofunctional and metabolic changes of heterogeneous muscle fibers during the persistent contraction. PMID:26019372

  3. Immunohistochemical and morphofunctional studies of skeletal muscle tissues with electric nerve stimulation by in vivo cryotechnique.

    PubMed

    Fukasawa, Yuki; Ohno, Nobuhiko; Saitoh, Yurika; Saigusa, Takeshi; Arita, Jun; Ohno, Shinichi

    2015-04-28

    In this study, morphological and immunohistochemical alterations of skeletal muscle tissues during persistent contraction were examined by in vivo cryotechnique (IVCT). Contraction of gastrocnemius muscles was induced by sciatic nerve stimulation. The IVCT was performed immediately, 3 min or 10 min after the stimulation start. Prominent ripples of muscle fibers or wavy deformation of sarcolemma were detected immediately after the stimulation, but they gradually diminished to normal levels during the stimulation. The relative ratio of sarcomere and A band lengths was the highest in the control group, but it immediately decreased to the lowest level and then gradually recovered at 3 min or 10 min. Although histochemical intensity of PAS reaction was almost homogeneous in muscle tissues of the control group or immediately after the stimulation, it decreased at 3 min or 10 min. Serum albumin was immunolocalized as dot-like patterns within some muscle fibers at 3 min stimulation. These patterns became more prominent at 10 min, and the dots got larger and saccular in some sarcoplasmic regions. However, IgG1 and IgM were immunolocalized in blood vessels under nerve stimulation conditions. Therefore, IVCT was useful to capture the morphofunctional and metabolic changes of heterogeneous muscle fibers during the persistent contraction.

  4. Potential of laryngeal muscle regeneration using induced pluripotent stem cell-derived skeletal muscle cells.

    PubMed

    Dirja, Bayu Tirta; Yoshie, Susumu; Ikeda, Masakazu; Imaizumi, Mitsuyoshi; Nakamura, Ryosuke; Otsuki, Koshi; Nomoto, Yukio; Wada, Ikuo; Hazama, Akihiro; Omori, Koichi

    2016-01-01

    Conclusion Induced pluripotent stem (iPS) cells may be a new potential cell source for laryngeal muscle regeneration in the treatment of vocal fold atrophy after recurrent laryngeal nerve paralysis. Objectives Unilateral vocal fold paralysis can lead to degeneration, atrophy, and loss of force of the thyroarytenoid muscle. At present, there are some treatments such as thyroplasty, arytenoid adduction, and vocal fold injection. However, such treatments cannot restore reduced mass of the thyroarytenoid muscle. iPS cells have been recognized as supplying a potential resource for cell transplantation. The aim of this study was to assess the effectiveness of the use of iPS cells for the regeneration of laryngeal muscle through the evaluation of both in vitro and in vivo experiments. Methods Skeletal muscle cells were generated from tdTomato-labeled iPS cells using embryoid body formation. Differentiation into skeletal muscle cells was analyzed by gene expression and immunocytochemistry. The tdTomato-labeled iPS cell-derived skeletal muscle cells were transplanted into the left atrophied thyroarytenoid muscle. To evaluate the engraftment of these cells after transplantation, immunohistochemistry was performed. Results The tdTomato-labeled iPS cells were successfully differentiated into skeletal muscle cells through an in vitro experiment. These cells survived in the atrophied thyroarytenoid muscle after transplantation.

  5. Spatially distributed sequential stimulation reduces fatigue in paralyzed triceps surae muscles: a case study.

    PubMed

    Nguyen, Robert; Masani, Kei; Micera, Silvestro; Morari, Manfred; Popovic, Milos R

    2011-12-01

    Functional electrical stimulation (FES) is limited by the rapid onset of muscle fatigue caused by localized nerve excitation repeatedly activating only a subset of motor units. The purpose of this study was to investigate reducing fatigue by sequentially changing, pulse by pulse, the area of stimulation using multiple surface electrodes that cover the same area as one electrode during conventional stimulation. Paralyzed triceps surae muscles of an individual with complete spinal cord injury were stimulated, via the tibial nerve, through four active electrodes using spatially distributed sequential stimulation (SDSS) that was delivered by sending a stimulation pulse to each electrode one after another with 90° phase shift between successive electrodes. For comparison, single electrode stimulation was delivered through one active electrode. For both modes of stimulation, the resultant frequency to the muscle as a whole was 40 Hz. Isometric ankle torque was measured during fatiguing stimulations lasting 2 min. Each mode of stimulation was delivered a total of six times over 12 separate days. Three fatigue measures were used for comparison: fatigue index (final torque normalized to maximum torque), fatigue time (time for torque to drop by 3 dB), and torque-time integral (over the entire trial). The measures were all higher during SDSS (P < 0.001), by 234, 280, and 171%, respectively. The results are an encouraging first step toward addressing muscle fatigue, which is one of the greatest problems for FES.

  6. Effects of a multichannel dynamic functional electrical stimulation system on hemiplegic gait and muscle forces

    PubMed Central

    Qian, Jing-guang; Rong, Ke; Qian, Zhenyun; Wen, Chen; Zhang, Songning

    2015-01-01

    [Purpose] The purpose of the study was to design and implement a multichannel dynamic functional electrical stimulation system and investigate acute effects of functional electrical stimulation of the tibialis anterior and rectus femoris on ankle and knee sagittal-plane kinematics and related muscle forces of hemiplegic gait. [Subjects and Methods] A multichannel dynamic electrical stimulation system was developed with 8-channel low frequency current generators. Eight male hemiplegic patients were trained for 4 weeks with electric stimulation of the tibia anterior and rectus femoris muscles during walking, which was coupled with active contraction. Kinematic data were collected, and muscle forces of the tibialis anterior and rectus femoris of the affected limbs were analyzed using a musculoskelatal modeling approach before and after training. A paired sample t-test was used to detect the differences between before and after training. [Results] The step length of the affected limb significantly increased after the stimulation was applied. The maximum dorsiflexion angle and maximum knee flexion angle of the affected limb were both increased significantly during stimulation. The maximum muscle forces of both the tibia anterior and rectus femoris increased significantly during stimulation compared with before functional electrical stimulation was applied. [Conclusion] This study established a functional electrical stimulation strategy based on hemiplegic gait analysis and musculoskeletal modeling. The multichannel functional electrical stimulation system successfully corrected foot drop and altered circumduction hemiplegic gait pattern. PMID:26696734

  7. Acupuncture plus low-frequency electrical stimulation (Acu-LFES) attenuates denervation-induced muscle atrophy

    PubMed Central

    Su (苏震), Zhen; Hu (虎力), Li; Cheng (程继忠), Jinzhong; Klein, Janet D.; Hassounah, Faten; Cai, Hui; Li (李敏), Min; Wang, Xiaonan H.

    2015-01-01

    Muscle wasting occurs in a variety of clinical situations, including denervation. There is no effective pharmacological treatment for muscle wasting. In this study, we used a tibial nerve denervation model to test acupuncture plus low-frequency electric stimulation (Acu-LFES) as a therapeutic strategy for muscle atrophy. Acupuncture needles were connected to an SDZ-II electronic acupuncture device delivering pulses at 20 Hz and 1 mA; the treatment was 15 min daily for 2 wk. Acu-LFES prevented soleus and plantaris muscle weight loss and increased muscle cross-sectional area in denervated mice. The abundances of Pax7, MyoD, myogenin, and embryonic myosin heavy chain were significantly increased by Acu-LFES in both normal and denervated muscle. The number of central nuclei was increased in Acu-LFES-treated muscle fibers. Phosphorylation of Akt was downregulated by denervation leading to a decline in muscle mass; however, Acu-LFES prevented the denervation-induced decline largely by upregulation of the IGF-1 signaling pathway. Acu-LFES reduced the abundance of muscle catabolic proteins forkhead O transcription factor and myostatin, contributing to the attenuated muscle atrophy. Acu-LFES stimulated the expression of macrophage markers (F4/80, IL-1b, and arginase-1) and inflammatory cytokines (IL-6, IFNγ, and TNFα) in normal and denervated muscle. Acu-LFES also stimulated production of the muscle-specific microRNAs miR-1 and miR-206. We conclude that Acu-LFES is effective in counteracting denervation-induced skeletal muscle atrophy and increasing muscle regeneration. Upregulation of IGF-1, downregulation of myostatin, and alteration of microRNAs contribute to the attenuation of muscle atrophy in denervated mice. PMID:26679610

  8. Acupuncture plus low-frequency electrical stimulation (Acu-LFES) attenuates denervation-induced muscle atrophy.

    PubMed

    Su, Zhen; Hu, Li; Cheng, Jinzhong; Klein, Janet D; Hassounah, Faten; Cai, Hui; Li, Min; Wang, Haidong; Wang, Xiaonan H

    2016-02-15

    Muscle wasting occurs in a variety of clinical situations, including denervation. There is no effective pharmacological treatment for muscle wasting. In this study, we used a tibial nerve denervation model to test acupuncture plus low-frequency electric stimulation (Acu-LFES) as a therapeutic strategy for muscle atrophy. Acupuncture needles were connected to an SDZ-II electronic acupuncture device delivering pulses at 20 Hz and 1 mA; the treatment was 15 min daily for 2 wk. Acu-LFES prevented soleus and plantaris muscle weight loss and increased muscle cross-sectional area in denervated mice. The abundances of Pax7, MyoD, myogenin, and embryonic myosin heavy chain were significantly increased by Acu-LFES in both normal and denervated muscle. The number of central nuclei was increased in Acu-LFES-treated muscle fibers. Phosphorylation of Akt was downregulated by denervation leading to a decline in muscle mass; however, Acu-LFES prevented the denervation-induced decline largely by upregulation of the IGF-1 signaling pathway. Acu-LFES reduced the abundance of muscle catabolic proteins forkhead O transcription factor and myostatin, contributing to the attenuated muscle atrophy. Acu-LFES stimulated the expression of macrophage markers (F4/80, IL-1b, and arginase-1) and inflammatory cytokines (IL-6, IFNγ, and TNFα) in normal and denervated muscle. Acu-LFES also stimulated production of the muscle-specific microRNAs miR-1 and miR-206. We conclude that Acu-LFES is effective in counteracting denervation-induced skeletal muscle atrophy and increasing muscle regeneration. Upregulation of IGF-1, downregulation of myostatin, and alteration of microRNAs contribute to the attenuation of muscle atrophy in denervated mice.

  9. Satellite cells in human skeletal muscle plasticity

    PubMed Central

    Snijders, Tim; Nederveen, Joshua P.; McKay, Bryon R.; Joanisse, Sophie; Verdijk, Lex B.; van Loon, Luc J. C.; Parise, Gianni

    2015-01-01

    Skeletal muscle satellite cells are considered to play a crucial role in muscle fiber maintenance, repair and remodeling. Our knowledge of the role of satellite cells in muscle fiber adaptation has traditionally relied on in vitro cell and in vivo animal models. Over the past decade, a genuine effort has been made to translate these results to humans under physiological conditions. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair/remodeling in response to exercise. Mounting evidence indicates that aging has a profound impact on the regulation of satellite cells in human skeletal muscle. Yet, the precise role of satellite cells in the development of muscle fiber atrophy with age remains unresolved. This review seeks to integrate recent results from in vivo human studies on satellite cell function in muscle fiber repair/remodeling in the wider context of satellite cell biology whose literature is largely based on animal and cell models. PMID:26557092

  10. Paradoxical effects of increased expression of PGC-1α on muscle mitochondrial function and insulin-stimulated muscle glucose metabolism

    PubMed Central

    Choi, Cheol Soo; Befroy, Douglas E.; Codella, Roberto; Kim, Sheene; Reznick, Richard M.; Hwang, Yu-Jin; Liu, Zhen-Xiang; Lee, Hui-Young; Distefano, Alberto; Samuel, Varman T.; Zhang, Dongyan; Cline, Gary W.; Handschin, Christoph; Lin, Jiandie; Petersen, Kitt F.; Spiegelman, Bruce M.; Shulman, Gerald I.

    2008-01-01

    Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α has been shown to play critical roles in regulating mitochondria biogenesis, respiration, and muscle oxidative phenotype. Furthermore, reductions in the expression of PGC-1α in muscle have been implicated in the pathogenesis of type 2 diabetes. To determine the effect of increased muscle-specific PGC-1α expression on muscle mitochondrial function and glucose and lipid metabolism in vivo, we examined body composition, energy balance, and liver and muscle insulin sensitivity by hyperinsulinemic-euglycemic clamp studies and muscle energetics by using 31P magnetic resonance spectroscopy in transgenic mice. Increased expression of PGC-1α in muscle resulted in a 2.4-fold increase in mitochondrial density, which was associated with an ≈60% increase in the unidirectional rate of ATP synthesis. Surprisingly, there was no effect of increased muscle PGC-1α expression on whole-body energy expenditure, and PGC-1α transgenic mice were more prone to fat-induced insulin resistance because of decreased insulin-stimulated muscle glucose uptake. The reduced insulin-stimulated muscle glucose uptake could most likely be attributed to a relative increase in fatty acid delivery/triglyceride reesterfication, as reflected by increased expression of CD36, acyl-CoA:diacylglycerol acyltransferase1, and mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase, that may have exceeded mitochondrial fatty acid oxidation, resulting in increased intracellular lipid accumulation and an increase in the membrane to cytosol diacylglycerol content. This, in turn, caused activation of PKCθ, decreased insulin signaling at the level of insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation, and skeletal muscle insulin resistance. PMID:19066218

  11. Bioelectrical activity of limb muscles during cold shivering of stimulation of the vestibular apparatus

    NASA Technical Reports Server (NTRS)

    Kuzmina, G. I.

    1980-01-01

    The effects of caloric and electric stimulation of the vestibular receptors on the EMG activity of limb muslces in anesthetized cats during cold induced shivering involved flexor muscles alone. Both types of stimulation suppressed bioelectrical activity more effectively in the ipsilateral muscles. The suppression of shivering activity seems to be due to the increased inhibitory effect of descending labyrinth pathways on the function of flexor motoneurons.

  12. Macrophage colony-stimulating factor-induced macrophage differentiation promotes regrowth in atrophied skeletal muscles and C2C12 myotubes.

    PubMed

    Dumont, Nicolas A; Frenette, Jérôme

    2013-02-01

    Skeletal muscle injury and regeneration are closely associated with an inflammatory reaction that is usually characterized by sequential recruitment of neutrophils and monocytes or macrophages. Selective macrophage depletion models have shown that macrophages are essential for complete regeneration of muscle fibers after freeze injuries, toxin injuries, ischemia-reperfusion, and hindlimb unloading and reloading. Although there is growing evidence that macrophages possess major myogenic capacities, it is not known whether the positive effects of macrophages can be optimized to stimulate muscle regrowth. We used in vivo and in vitro mouse models of atrophy to investigate the effects of stimulating macrophages with macrophage colony-stimulating factor (M-CSF) on muscle regrowth. When atrophied soleus muscles were injected intramuscularly with M-CSF, we observed a 1.6-fold increase in macrophage density and a faster recovery in muscle force (20%), combined with an increase in muscle fiber diameter (10%), after 7 days of reloading, compared with PBS-injected soleus muscles. Furthermore, coculture of atrophied myotubes with or without bone marrow-derived macrophages (BMDM) and/or M-CSF revealed that the combination of BMDMs and M-CSF was required to promote myotube growth (15%). More specifically, M-CSF promoted the anti-inflammatory macrophage phenotype, which in turn decreased protein degradation and MuRF-1 expression by 25% in growing myotubes. These results indicate that specific macrophage subsets can be stimulated to promote muscle cell regrowth after atrophy.

  13. Kinematic MRI study of upper-airway biomechanics using electrical muscle stimulation

    NASA Astrophysics Data System (ADS)

    Brennick, Michael J.; Margulies, Susan S.; Ford, John C.; Gefter, Warren B.; Pack, Allan I.

    1997-05-01

    We have developed a new and powerful method to study the movement and function of upper airway muscles. Our method is to use direct electrical stimulation of individual upper airway muscles, while performing state of the art high resolution magnetic resonance imaging (MRI). We have adapted a paralyzed isolated UA cat model so that positive or negative static pressure in the UA can be controlled at specific levels while electrical muscle stimulation is applied during MRI. With these techniques we can assess the effect of muscle stimulation on airway cross-sectional area compliance and soft tissue motion. We are reporting the preliminary results and MRI techniques which have enabled us to examine changes in airway dimensions which result form electrical stimulation of specific upper airway dilator muscles. The results of this study will be relevant to the development of new clinical treatments for obstructive sleep apnea by providing new information as to exactly how upper airway muscles function to dilate the upper airway and the strength of stimulation required to prevent the airway obstruction when overall muscle tone may not be sufficient to maintain regular breathing.

  14. Dietary obacunone supplementation stimulates muscle hypertrophy, and suppresses hyperglycemia and obesity through the TGR5 and PPARγ pathway

    SciTech Connect

    Horiba, Taro; Katsukawa, Masahiro; Mita, Moeko; Sato, Ryuichiro

    2015-08-07

    Obacunone is a limonoid that is predominantly found in Citrus. Although various biological activities of limonoids have been reported, little is known about the beneficial effects of obacunone on metabolic disorders. In the present study, we examined the effects of dietary obacunone supplementation on obese KKAy mice, to clarify the function of obacunone in metabolic regulation. Mice were pair-fed a normal diet either alone or supplemented with 0.1% w/w obacunone for 28 days. Compared with the control, obacunone-fed mice had lower glycosylated hemoglobin, blood glucose, and white adipose tissue weight, although there was no significant difference in body weight. Obacunone treatment also significantly increased the weight of the gastrocnemius and quadriceps muscles. Reporter gene assays revealed that obacunone stimulated the transcriptional activity of the bile acids-specific G protein-coupled receptor, TGR5, in a dose-dependent manner. In addition, obacunone inhibited adipocyte differentiation in 3T3-L1 cells and antagonized ligand-stimulated peroxisome proliferator-activated receptor γ (PPARγ) transcriptional activity. These results suggest that obacunone stimulates muscle hypertrophy and prevents obesity and hyperglycemia, and that these beneficial effects are likely to be mediated through the activation of TGR5 and inhibition of PPARγ transcriptional activity. - Highlights: • Citrus limonoid obacunone prevents hyperglycemia in obese, diabetic KKAy mice. • Obacunone reduces fat content and stimulates muscle hypertrophy in KKAy mice. • Obacunone stimulates TGR5 transcriptional activities. • Obacunone antagonizes PPARγ and inhibits lipid accumulation in adipocytes.

  15. Muscle Responses to Stimulation of the Tadpole Tail

    ERIC Educational Resources Information Center

    Funkhouser, Anne

    1976-01-01

    Describes use of tail muscles and spinal cord in the tadpole as an alternative source for muscle-and-nerve experiments. Includes explanation of simple dissection and preparation of tadpole; instructions for experiments such as threshold, strength of stimulus, frequency of stimulus, single twitch, tetanus, fatigue, effects of temperature on…

  16. The comparative effects of aminoglycoside antibiotics and muscle relaxants on electrical field stimulation response in rat bladder smooth muscle.

    PubMed

    Min, Chang Ho; Min, Young Sil; Lee, Sang Joon; Sohn, Uy Dong

    2016-06-01

    It has been reported that several aminoglycoside antibiotics have a potential of prolonging the action of non-depolarizing muscle relaxants by drug interactions acting pre-synaptically to inhibit acetylcholine release, but antibiotics itself also have a strong effect on relaxing the smooth muscle. In this study, four antibiotics of aminoglycosides such as gentamicin, streptomycin, kanamycin and neomycin were compared with skeletal muscle relaxants baclofen, tubocurarine, pancuronium and succinylcholine, and a smooth muscle relaxant, papaverine. The muscle strips isolated from the rat bladder were stimulated with pulse trains of 40 V in amplitude and 10 s in duration, with pulse duration of 1 ms at the frequency of 1-8 Hz, at 1, 2, 4, 6, 8 Hz respectively. To test the effect of four antibiotics on bladder smooth muscle relaxation, each of them was treated cumulatively from 1 μM to 0.1 mM with an interval of 5 min. Among the four antibiotics, gentamicin and neomycin inhibited the EFS response. The skeletal muscle relaxants (baclofen, tubocurarine, pancuronium and succinylcholine) and inhibitory neurotransmitters (GABA and glycine) did not show any significant effect. However, papaverine, had a significant effect in the relaxation of the smooth muscle. It was suggested that the aminoglycoside antibiotics have inhibitory effect on the bladder smooth muscle.

  17. Electrical Stimulation of Denervated Rat Skeletal Muscle Ameliorates Bone Fragility and Muscle Loss in Early-Stage Disuse Musculoskeletal Atrophy.

    PubMed

    Tamaki, Hiroyuki; Yotani, Kengo; Ogita, Futoshi; Hayao, Keishi; Nakagawa, Kouki; Sugawara, Kazuhiro; Kirimoto, Hikari; Onishi, Hideaki; Kasuga, Norikatsu; Yamamoto, Noriaki

    2017-04-01

    We tested whether daily muscle electrical stimulation (ES) can ameliorate the decrease in cortical bone strength as well as muscle and bone geometric and material properties in the early stages of disuse musculoskeletal atrophy. 7-week-old male F344 rats were randomly divided into three groups: age-matched control group (Cont); a sciatic denervation group (DN); and a DN + direct electrical stimulation group (DN + ES). Denervated tibialis anterior (TA) muscle in the DN + ES group received ES with 16 mA at 10 Hz for 30 min/day, 6 days/week. Micro CT, the three-point bending test, and immunohistochemistry were used to characterize cortical bone mechanical, structural, and material properties of tibiae. TA muscle in the DN + ES group showed significant improvement in muscle mass and myofiber cross-sectional area relative to the DN group. Maximal load and stiffness of tibiae, bone mineral density estimated by micro CT, and immunoreactivity of DMP1 in the cortical bone tissue were also significantly greater in the DN + ES group than in the DN group. These results suggest that daily ES-induced muscle contraction treatment reduced the decrease in muscle mass and cortical bone strength in early-stage disuse musculoskeletal atrophy and is associated with a beneficial effect on material properties such as mineralization of cortical bone tissue.

  18. Chronic effects of low-frequency low-intensity electrical stimulation of stretched human muscle

    NASA Astrophysics Data System (ADS)

    Shenkman, Boris S.; Lyubaeva, Ekaterina V.; Popov, Daniil V.; Netreba, Aleksey I.; Bravy, Yan R.; Tarakin, Pavel P.; Lemesheva, Yulia S.; Vinogradova, Olga L.

    2007-02-01

    Effects of low-frequency electrical stimulation, which is currently considered to be a possible countermeasure for long-duration spaceflights, with and without stretch were evaluated. Twelve young male volunteers were randomly distributed into two groups. In one group anterior thigh muscles—knee extensors of both legs were stimulated with frequency of 15 Hz for 4.5 wks, six times a week; each session was 6-h long. In the other group, electrical stimulation with the same parameters was applied to stretched knee extensors. Following stimulation the subjects exhibited an increase in fatigue resistance, and in the succinate dehydrogenase activity and a 10% gain in the percentage of muscle fibers with slow myosin heavy chain isoforms. In a stimulated group the peak voluntary strength went down significantly, the CSA of fast muscle fibers in m. quadriceps femoris became slightly less in size (10%). Electrical stimulation of the stretched muscles induced an insignificant decline in their strength and an increase of cross-sectional area of muscle fibers of both types. Thus chronic low-frequency electrical stimulation may be proposed as a candidate countermeasure against muscle strength and mass loss if it is combined with stretch.

  19. Dietary stimulators of the PGC-1 superfamily and mitochondrial biosynthesis in skeletal muscle. A mini-review.

    PubMed

    Vaughan, Roger A; Mermier, Christine M; Bisoffi, Marco; Trujillo, Kristina A; Conn, Carole A

    2014-03-01

    Mitochondrial dysfunction has been linked to many diseases including metabolic diseases such as diabetes. Peroxisome proliferator-activated receptor gamma co-activator 1 (PGC-1) is a superfamily of transcriptional co-activators which are important precursors to mitochondrial biosynthesis found in most cells including skeletal muscle. The PGC-1 superfamily consists of three variants all of which are directly involved in controlling metabolic gene expression including those regulating fatty acid oxidation and mitochondrial proteins. In contrast to previous reviews on PGC-1, this mini-review summarizes the current knowledge of many known dietary stimulators of PGC-1 and the subsequent mitochondrial biosynthesis with associated metabolic benefit in skeletal muscle.

  20. Contributions to muscle force and EMG by combined neural excitation and electrical stimulation

    NASA Astrophysics Data System (ADS)

    Crago, Patrick E.; Makowski, Nathaniel S.; Cole, Natalie M.

    2014-10-01

    Objective. Stimulation of muscle for research or clinical interventions is often superimposed on ongoing physiological activity without a quantitative understanding of the impact of the stimulation on the net muscle activity and the physiological response. Experimental studies show that total force during stimulation is less than the sum of the isolated voluntary and stimulated forces, but the occlusion mechanism is not understood. Approach. We develop a model of efferent motor activity elicited by superimposing stimulation during a physiologically activated contraction. The model combines action potential interactions due to collision block, source resetting, and refractory periods with previously published models of physiological motor unit recruitment, rate modulation, force production, and EMG generation in human first dorsal interosseous muscle to investigate the mechanisms and effectiveness of stimulation on the net muscle force and EMG. Main results. Stimulation during a physiological contraction demonstrates partial occlusion of force and the neural component of the EMG, due to action potential interactions in motor units activated by both sources. Depending on neural and stimulation firing rates as well as on force-frequency properties, individual motor unit forces can be greater, smaller, or unchanged by the stimulation. In contrast, voluntary motor unit EMG potentials in simultaneously stimulated motor units show progressive occlusion with increasing stimulus rate. The simulations predict that occlusion would be decreased by a reverse stimulation recruitment order. Significance. The results are consistent with and provide a mechanistic interpretation of previously published experimental evidence of force occlusion. The models also predict two effects that have not been reported previously—voluntary EMG occlusion and the advantages of a proximal stimulation site. This study provides a basis for the rational design of both future experiments and clinical

  1. Muscle Interstitial Cells: A Brief Field Guide to Non-satellite Cell Populations in Skeletal Muscle.

    PubMed

    Tedesco, Francesco Saverio; Moyle, Louise A; Perdiguero, Eusebio

    2017-01-01

    Skeletal muscle regeneration is mainly enabled by a population of adult stem cells known as satellite cells. Satellite cells have been shown to be indispensable for adult skeletal muscle repair and regeneration. In the last two decades, other stem/progenitor cell populations resident in the skeletal muscle interstitium have been identified as "collaborators" of satellite cells during regeneration. They also appear to have a key role in replacing skeletal muscle with adipose, fibrous, or bone tissue in pathological conditions. Here, we review the role and known functions of these different interstitial skeletal muscle cell types and discuss their role in skeletal muscle tissue homeostasis, regeneration, and disease, including their therapeutic potential for cell transplantation protocols.

  2. Battery-powered implantable nerve stimulator for chronic activation of two skeletal muscles using multichannel techniques.

    PubMed

    Lanmüller, H; Sauermann, S; Unger, E; Schnetz, G; Mayr, W; Bijak, M; Rafolt, D; Girsch, W

    1999-05-01

    Chronic activation of skeletal muscle is used clinically in representative numbers for diaphragm pacing to restore breathing and for dynamic graciloplasty to achieve fecal continence. The 3 different stimulation techniques currently used for electrophrenic respiration (EPR) all apply high frequency powered implants. It was our goal to make these stimulation methods applicable for EPR by a battery-powered nerve stimulator that would maximize the patient's freedom of movement. Additionally, the system should allow the implementation of multichannel techniques and alternating stimulation of 2 skeletal muscles as a further improvement in graciloplasty. Generally, the developed implantable nerve stimulator can be used for simultaneous and alternating activation of 2 skeletal muscles. Stimulation of the motor nerve is achieved by either single channel or multichannel methods. Carousel stimulation and sequential stimulation can be used for graciloplasty as well as for EPR. For EPR we calculated an operating time of the implant battery of 4.1 years based on the clinically used stimulation parameters with carousel stimulation. The multichannel pulse generator is hermetically sealed in a titanium case sized 65 x 17 mm (diameter x height) and weighs 88 g.

  3. Isolation, Culture and Identification of Porcine Skeletal Muscle Satellite Cells.

    PubMed

    Li, Bo-Jiang; Li, Ping-Hua; Huang, Rui-Hua; Sun, Wen-Xing; Wang, Han; Li, Qi-Fa; Chen, Jie; Wu, Wang-Jun; Liu, Hong-Lin

    2015-08-01

    The objective of this study was to establish the optimum protocol for the isolation and culture of porcine muscle satellite cells. Mononuclear muscle satellite cells are a kind of adult stem cell, which is located between the basal lamina and sarcolemma of muscle fibers and is the primary source of myogenic precursor cells in postnatal muscle. Muscle satellite cells are a useful model to investigate the mechanisms of muscle growth and development. Although the isolation and culture protocols of muscle satellite cells in some species (e.g. mouse) have been established successfully, the culture system for porcine muscle satellite cells is very limited. In this study, we optimized the isolation procedure of porcine muscle satellite cells and elaborated the isolation and culture process in detail. Furthermore, we characterized the porcine muscle satellite cells using the immunofluorecence. Our study provides a reference for the isolation of porcine muscle satellite cells and will be useful for studying the molecular mechanisms in these cells.

  4. Further observations on the facilitation of muscle responses to cortical stimulation by voluntary contraction.

    PubMed

    Thompson, P D; Day, B L; Rothwell, J C; Dressler, D; Maertens de Noordhout, A; Marsden, C D

    1991-10-01

    The effect of voluntary contraction on the discharge of single motor units following electrical and magnetic stimulation of the motor cortex was examined using the post-stimulus time histogram (PSTH) technique. The latencies of responses in single motor units of the first dorsal interosseous muscle to cortical stimulation were 2-4 msec shorter when the muscle was contracting than when at rest in 9 of 10 units studied. These latency differences are comparable with those recorded by surface electromyography for compound muscle action potentials following cortical stimulation in relaxed and active muscles. The new findings are that the intensity of cortical stimulation required to discharge a resting motor unit to produce a single PSTH peak produced multiple PSTH peaks when the same unit was contracting. The timing of the PSTH peak of relaxed motor unit discharge corresponded to one of the later PSTH peaks (usually the second) when the motor unit was voluntarily activated. These findings are in keeping with our previous suggestions that the longer latency of responses in relaxed muscles is due to the time taken for temporal summation of multiple descending corticospinal volleys at the cortico-motoneurone synapse. Facilitation produced by voluntary contraction occurs at least in part at the level of the spinal cord by lowering motoneurone threshold to enable discharge on the initial descending volley. The higher threshold of relaxed muscles is related to the higher intensities of stimulation needed to recruit multiple descending volleys and discharge resting motoneurones.

  5. Relation between abnormal patterns of muscle activation and response to common peroneal nerve stimulation in hemiplegia

    PubMed Central

    Burridge, J; McLellan, D

    2000-01-01

    OBJECTIVE—To investigate the relation between response to common peroneal nerve stimulation, timed to the swing phase of walking, and abnormal ankle movement and muscle activation patterns.
METHOD—Eighteen patients who took part had a drop foot and had had a stroke at least 6 months before the study Twelve age matched normal subjects were also studied. Response to stimulation was measured by changes in the speed and effort of walking when the stimulator was used. Speed was measured over 10 m and effort by the physiological cost index. Abnormal ankle movement and muscle activation were measured in a rig by ability to follow a tracking signal moving sinusoidally at either 1 or 2 Hz, resistance to passive movement, and EMG activity during both passive and active movements. Indices were derived to define EMG response to passive stretch, coactivation, and ability to activate muscles appropriately during active movement
RESULTS—Different mechanisms underlying the drop foot were seen. Results showed that patients who had poor control of ankle movement and spasticity, demonstrated by stretch reflex and coactivation, were more likely to respond well to stimulation. Those with mechanical resistance to passive movement and with normal muscle activation responded less well.
CONCLUSIONS—The results support the hypothesis that stimulation of the common peroneal nerve to elicit a contraction of the anterior tibial muscles also inhibits the antagonist calf muscles. The technique used may be useful in directing physiotherapy by indicating the underlying cause of the drop foot.

 PMID:10945810

  6. Magnetic stimulation for the measurement of respiratory and skeletal muscle function.

    PubMed

    Man, W D-C; Moxham, J; Polkey, M I

    2004-11-01

    Respiratory and skeletal muscle function is of interest in many areas of pulmonary and critical care medicine. The capacity of the respiratory muscle pump to respond to the load imposed by disease is the basis of an understanding of ventilatory failure. Over the last four decades, considerable progress has been made in quantifying the capacity of the respiratory muscles, in terms of strength, endurance and fatigue. With the development of magnetic stimulation, it has recently become possible to nonvolitionally assess the respiratory muscles in a clinically acceptable way. This is of particular interest in the investigation of patients receiving critical care, those with neuromuscular disease, and in children where volitional efforts are either not possible or likely to be sub-maximal. Furthermore, the adaptation of these techniques to quantify the strength of peripheral muscles, such as the quadriceps, has allowed the effects of muscle training or rehabilitation, uninfluenced by learning effect, to be assessed. This article focuses on the physiological basis of magnetic nerve stimulation, and reviews how the technique has been applied to measure muscle strength and fatigue, with particular emphasis upon the diaphragm. The translation of magnetic stimulation into a clinical tool is described, and how it may be of diagnostic, prognostic and therapeutic value in several areas of pulmonary medicine. In particular, the use of magnetic stimulation in neuromuscular disease, the intensive care setting, chronic obstructive pulmonary disease and paediatrics will be discussed.

  7. Classical and adaptive control of ex vivo skeletal muscle contractions using Functional Electrical Stimulation (FES)

    PubMed Central

    Shoemaker, Adam; Grange, Robert W.; Abaid, Nicole; Leonessa, Alexander

    2017-01-01

    Functional Electrical Stimulation is a promising approach to treat patients by stimulating the peripheral nerves and their corresponding motor neurons using electrical current. This technique helps maintain muscle mass and promote blood flow in the absence of a functioning nervous system. The goal of this work is to control muscle contractions from FES via three different algorithms and assess the most appropriate controller providing effective stimulation of the muscle. An open-loop system and a closed-loop system with three types of model-free feedback controllers were assessed for tracking control of skeletal muscle contractions: a Proportional-Integral (PI) controller, a Model Reference Adaptive Control algorithm, and an Adaptive Augmented PI system. Furthermore, a mathematical model of a muscle-mass-spring system was implemented in simulation to test the open-loop case and closed-loop controllers. These simulations were carried out and then validated through experiments ex vivo. The experiments included muscle contractions following four distinct trajectories: a step, sine, ramp, and square wave. Overall, the closed-loop controllers followed the stimulation trajectories set for all the simulated and tested muscles. When comparing the experimental outcomes of each controller, we concluded that the Adaptive Augmented PI algorithm provided the best closed-loop performance for speed of convergence and disturbance rejection. PMID:28273101

  8. MECHANISMS OF SMOOTH MUSCLE RELAXATION THROUGH THE ANODAL CURRENT STIMULATION.

    DTIC Science & Technology

    ELECTROPHYSIOLOGY, RELAXATION(PHYSIOLOGY), STIMULATION(PHYSIOLOGY), ELECTRICITY, IONS, ELECTROLYTES(PHYSIOLOGY), OSMOTIC PRESSURE, NERVES, NERVE FIBERS, CONTRACTION, HEART, CATS , DOGS , CRUSTACEA, JAPAN.

  9. Leucine supplementation stimulates protein synthesis and reduces degradation signal activation in muscle of newborn pigs during acute endotoxemia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sepsis disrupts skeletal muscle proteostasis and mitigates the anabolic response to leucine (Leu) in muscle of mature animals. We have shown that Leu stimulates muscle protein synthesis (PS) in healthy neonatal piglets. To determine if supplemental Leu can stimulate PS and reduce protein degradation...

  10. Effect of surface neuromuscular electrical stimulation on labial and lingual muscles in healthy volunteers.

    PubMed

    Safi, Mohammed F; Wright-Harp, Wilhelmina; Lucker, Jay R; Payne, Joan C

    2017-01-31

    Neuromuscular electrical stimulation (NMES) may have potential as a treatment for muscle weakness as it may improve strength when applied to the orofacial muscles. However, before incorporating this procedure into clinical practice, research is needed to investigate its effects on lingual and facial muscles of speech and mastication. The aim of this study was to determine what effect(s) submental and labial NMES would have on lingual and labial muscle strength in healthy participants. Fourteen healthy adults (27-49 years old) were assigned to two groups (treatment and control). A pretreatment and post-treatment test using the Iowa Oral Performance Instrument was used to measure the strength of labial and lingual muscles in both groups. Participants in the treatment group received labial and submental NMES while performing a structured labial, buccal, and lingual exercise program. In contrast, participants in the control group completed the same oral motor exercise program without stimulation.

  11. Oxidative stress stimulates skeletal muscle glucose uptake through a phosphatidylinositol 3-kinase-dependent pathway

    PubMed Central

    Higaki, Yasuki; Mikami, Toshio; Fujii, Nobuharu; Hirshman, Michael F.; Koyama, Katsuhiro; Seino, Tetsuya; Tanaka, Keitaro; Goodyear, Laurie J.

    2010-01-01

    We determined the acute effects of oxidative stress on glucose uptake and intracellular signaling in skeletal muscle by incubating muscles with reactive oxygen species (ROS). Xanthine oxidase (XO) is a superoxide-generating enzyme that increases ROS. Exposure of isolated rat extensor digitorum longus (EDL) muscles to Hx/XO (Hx/XO) for 20 min resulted in a dose-dependent increase in glucose uptake. To determine whether the mechanism leading to Hx/XO-stimulated glucose uptake is associated with the production of H2O2, EDL muscles from rats were preincubated with the H2O2 scavenger catalase or the superoxide scavenger superoxide dismutase (SOD) prior to incubation with Hx/XO. Catalase treatment, but not SOD, completely inhibited the increase in Hx/XO-stimulated 2-deoxyglucose (2-DG) uptake, suggesting that H2O2 is an intermediary leading to Hx/XO-stimulated glucose uptake with incubation. Direct H2O2 also resulted in a dose-dependent increase in 2-DG uptake in isolated EDL muscles, and the maximal increase was threefold over basal levels at a concentration of 600 μmol/l H2O2. H2O2-stimulated 2-DG uptake was completely inhibited by the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin, but not the nitric oxide inhibitor NG-monomethyl-L-arginine. H2O2 stimulated the phosphorylation of Akt Ser473 (7-fold) and Thr308 (2-fold) in isolated EDL muscles. H2O2 at 600 μmol/l had no effect on ATP concentrations and did not increase the activities of either the α1 or α2 catalytic isoforms of AMP-activated protein kinase. These results demonstrate that acute exposure of muscle to ROS is a potent stimulator of skeletal muscle glucose uptake and that this occurs through a PI3K-dependent mechanism. PMID:18303121

  12. Myosin types in cultured muscle cells

    PubMed Central

    1980-01-01

    Fluorescent antibodies against fast skeletal, slow skeletal, and ventricular myosins were applied to muscle cultures from embryonic pectoralis and ventricular myocadium of the chicken. A number of spindle-shaped mononucleated cells, presumably myoblasts, and all myotubes present in skeletal muscle cultures were labeled by all three antimyosin antisera. In contrast, in cultures from ventricular myocardium all muscle cells were labeled by anti-ventricular myosin, whereas only part of them were stained by anti-slow skeletal myosin and rare cells reacted with anti-fast skeletal myosin. The findings indicate that myosin(s) present in cultured embryonic skeletal muscle cells contains antigenic determinants similar to those present in adult fast skeletal, slow skeletal, and ventricular myosins. PMID:6156177

  13. Muscle cells provide instructions for planarian regeneration.

    PubMed

    Witchley, Jessica N; Mayer, Mirjam; Wagner, Daniel E; Owen, Jared H; Reddien, Peter W

    2013-08-29

    Regeneration requires both potential and instructions for tissue replacement. In planarians, pluripotent stem cells have the potential to produce all new tissue. The identities of the cells that provide regeneration instructions are unknown. Here, we report that position control genes (PCGs) that control regeneration and tissue turnover are expressed in a subepidermal layer of nonneoblast cells. These subepidermal cells coexpress many PCGs. We propose that these subepidermal cells provide a system of body coordinates and positional information for regeneration, and identify them to be muscle cells of the planarian body wall. Almost all planarian muscle cells express PCGs, suggesting a dual function: contraction and control of patterning. PCG expression is dynamic in muscle cells after injury, even in the absence of neoblasts, suggesting that muscle is instructive for regeneration. We conclude that planarian regeneration involves two highly flexible systems: pluripotent neoblasts that can generate any new cell type and muscle cells that provide positional instructions for the regeneration of any body region.

  14. MAP kinase activator from insulin-stimulated skeletal muscle is a protein threonine/tyrosine kinase.

    PubMed Central

    Nakielny, S; Cohen, P; Wu, J; Sturgill, T

    1992-01-01

    A 'MAP kinase activator' was purified several thousand-fold from insulin-stimulated rabbit skeletal muscle, which resembled the 'activator' from nerve growth factor-stimulated PC12 cells in that it could be inactivated by incubation with protein phosphatase 2A, but not by protein tyrosine phosphatases and its apparent molecular mass was 45-50 kDa. In the presence of MgATP, 'MAP kinase activator' converted the normal 'wild-type' 42 kDa MAP kinase from an inactive dephosphorylated form to the fully active diphosphorylated species. Phosphorylation occurred on the same threonine and tyrosine residues which are phosphorylated in vivo in response to growth factors or phorbol esters. A mutant MAP kinase produced by changing a lysine at the active centre to arginine was phosphorylated in an identical manner by the 'MAP kinase activator', but no activity was generated. The results demonstrate that 'MAP kinase activator' is a protein kinase (MAP kinase kinase) and not a protein that stimulates the autophosphorylation of MAP kinase. MAP kinase kinase is the first established example of a protein kinase that can phosphorylate an exogenous protein on threonine as well as tyrosine residues. Images PMID:1318193

  15. Depressed tetanic contactile function cannot be compensated by increasing stimulating frequency in unloaded soleus muscle

    NASA Astrophysics Data System (ADS)

    Gao, Fang; Yu, Zhi-Bin

    2005-08-01

    The weightlessness-induced muscle atrophy is associated with a reduced force and power and with an increased fatigability [1]. In prolonged manned space missions, these alterations in skeletal muscles could limit the crew's ability to work in space and to rapidly egress in an emergency on return to Earth. In order to elucidate the underlying mechanisms of the increased fatigability in the atrophic skeletal muscle, we isolated the typically fast and slow muscle, extensor digitorum longus (EDL) and soleus (SOL), to observe the changes in maximal contraction tension, optimal stimulating frequency, and recovery features after fatigue in the intermittent tetanic contraction.

  16. Stromal derived factor‐1 and granulocyte‐colony stimulating factor treatment improves regeneration of Pax7−/− mice skeletal muscles

    PubMed Central

    Kowalski, Kamil; Archacki, Rafał; Archacka, Karolina; Stremińska, Władysława; Paciorek, Anna; Gołąbek, Magdalena; Ciemerych, Maria A.

    2015-01-01

    Abstract Background The skeletal muscle has the ability to regenerate after injury. This process is mediated mainly by the muscle specific stem cells, that is, satellite cells. In case of extensive damage or under pathological conditions, such as muscular dystrophy, the process of muscle reconstruction does not occur properly. The aim of our study was to test whether mobilized stem cells, other than satellite cells, could participate in skeletal muscle reconstruction. Methods Experiments were performed on wild‐type mice and mice lacking the functional Pax7 gene, that is, characterized by the very limited satellite cell population. Gastrocnemius mice muscles were injured by cardiotoxin injection, and then the animals were treated by stromal derived factor‐1 (Sdf‐1) with or without granulocyte‐colony stimulating factor (G‐CSF) for 4 days. The muscles were subjected to thorough assessment of the tissue regeneration process using histological and in vitro methods, as well as evaluation of myogenic factors' expression at the transcript and protein levels. Results Stromal derived factor‐1 alone and Sdf‐1 in combination with G‐CSF significantly improved the regeneration of Pax7−/− skeletal muscles. The Sdf‐1 and G‐CSF treatment caused an increase in the number of mononucleated cells associated with muscle fibres. Further analysis showed that Sdf‐1 and G‐CSF treatment led to the rise in the number of CD34+ and Cxcr4+ cells and expression of Cxcr7. Conclusions Stromal derived factor‐1 and G‐CSF stimulated regeneration of the skeletal muscles deficient in satellite cells. We suggest that mobilized CD34+, Cxcr4+, and Cxcr7+ cells can efficiently participate in the skeletal muscle reconstruction and compensate for the lack of satellite cells. PMID:27239402

  17. Highly efficient, functional engraftment of skeletal muscle stem cells in dystrophic muscles.

    PubMed

    Cerletti, Massimiliano; Jurga, Sara; Witczak, Carol A; Hirshman, Michael F; Shadrach, Jennifer L; Goodyear, Laurie J; Wagers, Amy J

    2008-07-11

    Satellite cells reside beneath the basal lamina of skeletal muscle fibers and include cells that act as precursors for muscle growth and repair. Although they share a common anatomical localization and typically are considered a homogeneous population, satellite cells actually exhibit substantial heterogeneity. We used cell-surface marker expression to purify from the satellite cell pool a distinct population of skeletal muscle precursors (SMPs) that function as muscle stem cells. When engrafted into muscle of dystrophin-deficient mdx mice, purified SMPs contributed to up to 94% of myofibers, restoring dystrophin expression and significantly improving muscle histology and contractile function. Transplanted SMPs also entered the satellite cell compartment, renewing the endogenous stem cell pool and participating in subsequent rounds of injury repair. Together, these studies indicate the presence in adult skeletal muscle of prospectively isolatable muscle-forming stem cells and directly demonstrate the efficacy of myogenic stem cell transplant for treating muscle degenerative disease.

  18. BRAF activates PAX3 to control muscle precursor cell migration during forelimb muscle development

    PubMed Central

    Shin, Jaeyoung; Watanabe, Shuichi; Hoelper, Soraya; Krüger, Marcus; Kostin, Sawa; Pöling, Jochen; Kubin, Thomas; Braun, Thomas

    2016-01-01

    Migration of skeletal muscle precursor cells is a key step during limb muscle development and depends on the activity of PAX3 and MET. Here, we demonstrate that BRAF serves a crucial function in formation of limb skeletal muscles during mouse embryogenesis downstream of MET and acts as a potent inducer of myoblast cell migration. We found that a fraction of BRAF accumulates in the nucleus after activation and endosomal transport to a perinuclear position. Mass spectrometry based screening for potential interaction partners revealed that BRAF interacts and phosphorylates PAX3. Mutation of BRAF dependent phosphorylation sites in PAX3 impaired the ability of PAX3 to promote migration of C2C12 myoblasts indicating that BRAF directly activates PAX3. Since PAX3 stimulates transcription of the Met gene we propose that MET signaling via BRAF fuels a positive feedback loop, which maintains high levels of PAX3 and MET activity required for limb muscle precursor cell migration. DOI: http://dx.doi.org/10.7554/eLife.18351.001 PMID:27906130

  19. Molecular and Cellular Mechanisms of Muscle Aging and Sarcopenia and Effects of Electrical Stimulation in Seniors

    PubMed Central

    Barberi, Laura; Scicchitano, Bianca Maria

    2015-01-01

    The prolongation of skeletal muscle strength in aging and neuromuscular disease has been the objective of numerous studies employing a variety of approaches. It is generally accepted that cumulative failure to repair damage related to an overall decrease in anabolic processes is a primary cause of functional impairment in muscle. The functional performance of skeletal muscle tissues declines during post- natal life and it is compromised in different diseases, due to an alteration in muscle fiber composition and an overall decrease in muscle integrity as fibrotic invasions replace functional contractile tissue. Characteristics of skeletal muscle aging and diseases include a conspicuous reduction in myofiber plasticity (due to the progressive loss of muscle mass and in particular of the most powerful fast fibers), alteration in muscle-specific transcriptional mechanisms, and muscle atrophy. An early decrease in protein synthetic rates is followed by a later increase in protein degradation, to affect biochemical, physiological, and morphological parameters of muscle fibers during the aging process. Alterations in regenerative pathways also compromise the functionality of muscle tissues. In this review we will give an overview of the work on molecular and cellular mechanisms of aging and sarcopenia and the effects of electrical stimulation in seniors.. PMID:26913161

  20. Concomitant responses of upper airway stabilizing muscles to transcranial magnetic stimulation in normal men.

    PubMed

    Sériès, Frédéric; Wang, Wei; Mélot, Christian; Similowski, Thomas

    2008-04-01

    Upper airway stabilizing muscles play a crucial role in the maintenance of upper airway patency. Transcranial magnetic stimulation allows the investigation of the corticomotor activation process for respiratory muscles. This technique has also been used to evaluate the genioglossus corticomotor response. The aims of this study were to characterize the response of different upper airway stabilizing muscles to focal cortical stimulation of the genioglossus. Alae nasi, genioglossus, levator palatini, palatoglossus and diaphragm motor-evoked potential responses to transcranial magnetic stimulation were recorded during expiration, tidal inspiration and deep inspiration in nine normal awake subjects. A concomitant response of the four studied upper airway muscles was observed in the majority of cortical stimuli. The response of these muscles was independent of the diaphragmatic one that was only occasionally observed. Significant positive relationships were found between alae nasi, levator palatini and palatoglossus motor-evoked potential latencies and amplitudes and the corresponding values of the genioglossus. We conclude that transcranial magnetic stimulation applied in the genioglossus area induces a concomitant motor response of upper airway stabilizing muscles with consistent changes in their motor responses during inspiratory manoeuvres.

  1. Replication of Muscle Cell Using Bioimprint

    NASA Astrophysics Data System (ADS)

    Samsuri, Fahmi; Mitchell, John S.; Alkaisi, Maan M.; Evans, John J.

    2009-07-01

    In our earlier study a heat-curable PDMS or a UV curable elastomer, was used as the replicating material to introduce Bioimprint methodology to facilitate cell imaging [1-2] But, replicating conditions for thermal polymerization is known to cause cell dehydration during curing. In this study, a new type of polymer was developed for use in living cell replica formation, and it was tested on human muscle cells. The cells were incubated and cultured according to standard biological culturing procedures, and they were grown for about 10 days. The replicas were then separated from the muscle cells and taken for analysis under an Atomic Force Microscope (AFM). The new polymer was designed to be biocompatible with higher resolution and fast curing process compared to other types of silicon-based organic polymers such as polydimethylsiloxane (PDMS). Muscle cell imprints were achieved and higher resolution images were able to show the micro structures of the muscle cells, including the cellular fibers and cell membranes. The AFM is able to image features at nanoscale resolution. This capacity enables a number of characteristics of biological cells to be visualized in a unique manner. Polymer and muscle cells preparations were developed at Hamilton, in collaboration between Plant and Food Research and the Department of Electrical and Computer Engineering, University of Canterbury. Tapping mode was used for the AFM image analysis as it has low tip-sample forces and non-destructive imaging capability. We will be presenting the bioimprinting processes of muscle cells, their AFM imaging and characterization of the newly developed polymer.

  2. Muscle cell attachment in Caenorhabditis elegans

    PubMed Central

    1991-01-01

    In the nematode Caenorhabditis elegans, the body wall muscles exert their force on the cuticle to generate locomotion. Interposed between the muscle cells and the cuticle are a basement membrane and a thin hypodermal cell. The latter contains bundles of filaments attached to dense plaques in the hypodermal cell membranes, which together we have called a fibrous organelle. In an effort to define the chain of molecules that anchor the muscle cells to the cuticle we have isolated five mAbs using preparations enriched in these components. Two antibodies define a 200-kD muscle antigen likely to be part of the basement membrane at the muscle/hypodermal interface. Three other antibodies probably identify elements of the fibrous organelles in the adjacent hypodermis. The mAb IFA, which reacts with mammalian intermediate filaments, also recognizes these structures. We suggest that the components recognized by these antibodies are likely to be involved in the transmission of tension from the muscle cell to the cuticle. PMID:1860880

  3. Slow motor neuron stimulation of locust skeletal muscle: model and measurement.

    PubMed

    Wilson, Emma; Rustighi, Emiliano; Newland, Philip L; Mace, Brian R

    2013-06-01

    The isometric force response of the locust hind leg extensor tibia muscle to stimulation of a slow extensor tibia motor neuron is experimentally investigated, and a mathematical model describing the response presented. The measured force response was modelled by considering the ability of an existing model, developed to describe the response to the stimulation of a fast extensor tibia motor neuron and to also model the response to slow motor neuron stimulation. It is found that despite large differences in the force response to slow and fast motor neuron stimulation, which could be accounted for by the differing physiology of the fibres they innervate, the model is able to describe the response to both fast and slow motor neuron stimulation. Thus, the presented model provides a potentially generally applicable, robust, simple model to describe the isometric force response of a range of muscles.

  4. Pain and soreness associated with a percutaneous electrical stimulation muscle cramping protocol.

    PubMed

    Miller, Kevin C; Knight, Kenneth L

    2007-11-01

    Muscle cramps are difficult to study scientifically because of their spontaneity and unpredictability. Various laboratory techniques to induce muscle cramps have been explored but the best technique for inducing cramps is unclear. Electrical stimulation appears to be the most reliable, but there is a perception that it is extremely painful. Data to support this perception are lacking. We hypothesized that electrical stimulation is a tolerable method of inducing cramps with few side effects. We measured cramp frequency (HZ), pain during electrical stimulation, and soreness before, at 5 s, and 30, 60, and 90 min after cramp induction using a 100-mm visual analog scale. Group 1 received tibial nerve stimulation on 5 consecutive days; Group 2 received it on alternate days for five total treatments. Pain and soreness were mild. The highest ratings occurred on Day 1 and decreased thereafter. Intersession reliability was high. Our study showed that electrical stimulation causes little pain or soreness and is a reliable method for inducing cramps.

  5. Salbutamol and chronic low-frequency stimulation of canine skeletal muscle.

    PubMed Central

    Hu, P; Zhang, K M; Feher, J J; Wang, S W; Wright, L D; Wechsler, A S; Spratt, J A; Briggs, F N

    1996-01-01

    1. The effect of simultaneous application of chronic muscle stimulation and salbutamol on the expression of mRNAs and proteins normally expressed by fast- or slow-twitch fibres was followed and the effects of changes in protein expression on mechanical performance were evaluated. Chronic low-frequency stimulation increased the myosin heavy chain (HC)-I level in the canine latissimus dorsi muscle and simultaneous administration of salbutamol partially blocked this change. Associated with the increase in HC-I level was a decrease in the velocity of shortening at zero load, VMAX. The change in VMAX was partially blocked by salbutamol. 2. Chronic low-frequency stimulation increased the levels of slow-twitch cardiac isoform sarco-/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban mRNA, and SERCA2a and phospholamban protein expression. These changes were associated with an increase in time-to-peak tension and a decrease in fusion frequency. Simultaneous administration of salbutamol blocked these changes in protein expression and muscle mechanics. Chronic stimulation of latissimus dorsi decreased the levels of the fast-twitch isoform of sarco-/endoplasmic reticulum Ca(2+)-ATPase (SERCA1a) and increased SERCA2a protein expression and decreased calcium uptake rate by muscle homogenates. These changes were blocked by salbutamol. 3. The loss of latissimus dorsi muscle weight by chronic stimulation was partially blocked by salbutamol. Images Figure 1 Figure 4 PMID:8910210

  6. Masses of inositol phosphates in resting and tetanically stimulated vertebrate skeletal muscles.

    PubMed

    Mayr, G W; Thieleczek, R

    1991-12-15

    The masses of inositol phosphates have been determined in isolated skeletal muscles from Xenopus laevis (sartorius, tibialis anterior and iliofibularis) and rat (gastrocnemius and soleus) which were quick-frozen in the resting state and at different stages of an isometric (Xenopus) or isotonic (rat) tetanus. The isomeric spectrum of inositol phosphates detected was similar to that in other tissues and cell types. The total sarcoplasmic concentrations of the isomers Ins-(1,4,5,6)P4/Ins(3,4,5,6)P4 (0.2-0.9 microM), Ins(1,3,4,6)P4 (not detectable), Ins(1,3,4,5,6)P5 (about 1 microM) and InsP6 (3.2-4.6 microM) were lower than in other cell types. Variations in these concentrations were due to the muscle type rather than to the donor species. The putative second messenger Ins(1,4,5)P3, as well as its dephosphorylation product Ins(1,4)P2, were present at surprisingly high total myoplasmic resting concentrations, ranging from 1.2 to 2.5 microM and 3.5 to 6.9 microM respectively. Upon tetanic stimulation these two inositol phosphates in particular exhibited significantly increased total sarcoplasmic concentrations, up to 4.2 microM and 11.3 microM respectively, with a time scale of seconds. From the initial rate of increase in the total sarcoplasmic concentrations of Ins(1,4,5)P3 and its rapidly formed metabolic products, a minimal phosphoinositidase C (PIC) activity in tetanically activated Xenopus skeletal muscle of about 1.7-2.6 microM/s can be estimated. This PIC activity observed in vivo seems to be far too low to account for a functional role for Ins(1,4,5)P3 as a chemical transmitter in the fast excitation-contraction coupling (ECC) process in skeletal muscle. The presence of Ins(1,3,4,5)P4 in all muscle types is indicative of a Ca(2+)-activated Ins(1,4,5)P3 3-kinase activity. The rapid transient increases in Ins(1,3,4)P3 and Ins(1,3)P2 in isometrically contracting Xenopus muscles suggest that corresponding Ins(1,3,4,5)P4 phosphatases are operating in skeletal muscle

  7. A single session of neuromuscular electrical stimulation does not augment postprandial muscle protein accretion.

    PubMed

    Dirks, Marlou L; Wall, Benjamin T; Kramer, Irene Fleur; Zorenc, Antoine H; Goessens, Joy P B; Gijsen, Annemie P; van Loon, Luc J C

    2016-07-01

    The loss of muscle mass and strength that occurs with aging, termed sarcopenia, has been (at least partly) attributed to an impaired muscle protein synthetic response to food intake. Previously, we showed that neuromuscular electrical stimulation (NMES) can stimulate fasting muscle protein synthesis rates and prevent muscle atrophy during disuse. We hypothesized that NMES prior to protein ingestion would increase postprandial muscle protein accretion. Eighteen healthy elderly (69 ± 1 yr) males participated in this study. After a 70-min unilateral NMES protocol was performed, subjects ingested 20 g of intrinsically l-[1-(13)C]phenylalanine-labeled casein. Plasma samples and muscle biopsies were collected to assess postprandial mixed muscle and myofibrillar protein accretion as well as associated myocellular signaling during a 4-h postprandial period in both the control (CON) and stimulated (NMES) leg. Protein ingestion resulted in rapid increases in both plasma phenylalanine concentrations and l-[1-(13)C]phenylalanine enrichments, which remained elevated during the entire 4-h postprandial period (P < 0.05). Mixed-muscle protein-bound l-[1-(13)C]phenylalanine enrichments increased significantly over time following protein ingestion, with no differences between the CON (0.0164 ± 0.0019 MPE) and NMES (0.0164 ± 0.0019 MPE) leg (P > 0.05). In agreement, no differences were observed in the postprandial rise in myofibrillar protein bound l-[1-(13)C]phenylalanine enrichments between the CON and NMES legs (0.0115 ± 0.0014 vs. 0.0133 ± 0.0013 MPE, respectively, P > 0.05). Significant increases in mTOR and P70S6K phosphorylation status were observed in the NMES-stimulated leg only (P < 0.05). We conclude that a single session of NMES prior to food intake does not augment postprandial muscle protein accretion in healthy older men.

  8. Satellite Cells Contribution to Exercise Mediated Muscle Hypertrophy and Repair

    PubMed Central

    Bazgir, Behzad; Fathi, Rouhollah; Rezazadeh Valojerdi, Mojtaba; Mozdziak, Paul; Asgari, Alireza

    2017-01-01

    Satellite cells (SCs) are the most abundant skeletal muscle stem cells. They are widely recognized for their contributions to maintenance of muscle mass, regeneration and hypertrophy during the human life span. These cells are good candidates for cell therapy due to their self-renewal capabilities and presence in an undifferentiated form. Presently, a significant gap exists between our knowledge of SCs behavior and their application as a means for human skeletal muscle tissue repair and regeneration. Both physiological and pathological stimuli potentially affect SCs activation, proliferation, and terminal differentiation the former category being the focus of this article. Activation of SCs occurs following exercise, post-training micro-injuries, and electrical stimulation. Exercise, as a potent and natural stimulus, is at the center of numerous studies on SC activation and relevant fields. According to research, different exercise modalities end with various effects. This review article attempts to picture the state of the art of the SCs life span and their engagement in muscle regeneration and hypertrophy in exercise. PMID:28042532

  9. Preventive effects of kilohertz frequency electrical stimulation on sepsis-induced muscle atrophy

    PubMed Central

    Tanaka, M.; Tanaka, K.; Tategaki, J.; Fujino, H.

    2016-01-01

    Objectives: The present study sought to evaluate the effect of electrical stimulation (ES) by using kilohertz frequency on muscle atrophy induced by sepsis. Methods: Seventeen male ICR mice were randomly divided into 3 groups: control, lipopolysaccharide (LPS)-injected for 4 days, LPS plus ES (LPS+ES). Sepsis was induced by 4 days of an intraperitoneal LPS injection (10 µg/g body weight/day). LPS+ES animals received the LPS injections and ES twice a day for 4 days. ELISA and western blot analysis determined the plasma levels of inflammatory cytokines and ubiquitinated proteins, while the tibialis anterior muscles were weighed and muscle fiber cross-sectional area (CSA) were measured to assess muscle atrophy, which were analyzed by Student’s t-test and ANOVA. Results: LPS induced increased plasma levels of inflammatory cytokines, significant muscle mass loss (LPS:-29.0%, LPS+ES:-23.1%), decreased fiber cross-sectional area, and an up-regulation of atrogin-1 and ubiquitinated proteins in the tibialis anterior muscle compared with the control. ES attenuated the sepsis-induced loss of muscle mass and decreased fiber CSA, as well as attenuated the atrogin-1 and ubiquitinated protein up-regulation. Conclusions: Electrical stimulation may prevent sepsis-induced muscle atrophy through ubiquitin-proteasome pathway inhibition. PMID:27282459

  10. Regulation of Gastrointestinal Smooth Muscle Function by Interstitial Cells.

    PubMed

    Sanders, Kenton M; Kito, Yoshihiko; Hwang, Sung Jin; Ward, Sean M

    2016-09-01

    Interstitial cells of mesenchymal origin form gap junctions with smooth muscle cells in visceral smooth muscles and provide important regulatory functions. In gastrointestinal (GI) muscles, there are two distinct classes of interstitial cells, c-Kit(+) interstitial cells of Cajal and PDGFRα(+) cells, that regulate motility patterns. Loss of these cells may contribute to symptoms in GI motility disorders.

  11. Dichloroacetate inhibits glycolysis and augments insulin-stimulated glycogen synthesis in rat muscle.

    PubMed Central

    Clark, A S; Mitch, W E; Goodman, M N; Fagan, J M; Goheer, M A; Curnow, R T

    1987-01-01

    The decrease in plasma lactate during dichloroacetate (DCA) treatment is attributed to stimulation of lactate oxidation. To determine whether DCA also inhibits lactate production, we measured glucose metabolism in muscles of fed and fasted rats incubated with DCA and insulin. DCA increased glucose-6-phosphate, an allosteric modifier of glycogen synthase, approximately 50% and increased muscle glycogen synthesis and glycogen content greater than 25%. Lactate release fell; inhibition of glycolysis accounted for greater than 80% of the decrease. This was associated with a decrease in intracellular AMP, but no change in citrate or ATP. When lactate oxidation was increased by raising extracellular lactate, glycolysis decreased (r = - 0.91), suggesting that lactate oxidation regulates glycolysis. When muscle lactate production was greatly stimulated by thermal injury, DCA increased glycogen synthesis, normalized glycogen content, and inhibited glycolysis, thereby reducing lactate release. The major effect of DCA on lactate metabolism in muscle is to inhibit glycolysis. PMID:3543056

  12. Wide-pulse-high-frequency neuromuscular stimulation of triceps surae induces greater muscle fatigue compared with conventional stimulation.

    PubMed

    Neyroud, Daria; Dodd, David; Gondin, Julien; Maffiuletti, Nicola A; Kayser, Bengt; Place, Nicolas

    2014-05-15

    We compared the extent and origin of muscle fatigue induced by short-pulse-low-frequency [conventional (CONV)] and wide-pulse-high-frequency (WPHF) neuromuscular electrical stimulation. We expected CONV contractions to mainly originate from depolarization of axonal terminal branches (spatially determined muscle fiber recruitment) and WPHF contractions to be partly produced via a central pathway (motor unit recruitment according to size principle). Greater neuromuscular fatigue was, therefore, expected following CONV compared with WPHF. Fourteen healthy subjects underwent 20 WPHF (1 ms-100 Hz) and CONV (50 μs-25 Hz) evoked isometric triceps surae contractions (work/rest periods 20:40 s) at an initial target of 10% of maximal voluntary contraction (MVC) force. Force-time integral of the 20 evoked contractions (FTI) was used as main index of muscle fatigue; MVC force loss was also quantified. Central and peripheral fatigue were assessed by voluntary activation level and paired stimulation amplitudes, respectively. FTI in WPHF was significantly lower than in CONV (21,717 ± 11,541 vs. 37,958 ± 9,898 N·s P<0,001). The reductions in MVC force (WPHF: -7.0 ± 2.7%; CONV: -6.2 ± 2.5%; P < 0.01) and paired stimulation amplitude (WPHF: -8.0 ± 4.0%; CONV: -7.4 ± 6.1%; P < 0.001) were similar between conditions, whereas no change was observed for voluntary activation level (P > 0.05). Overall, our results showed a different motor unit recruitment pattern between the two neuromuscular electrical stimulation modalities with a lower FTI indicating greater muscle fatigue for WPHF, possibly limiting the presumed benefits for rehabilitation programs.

  13. Short-latency tachycardia evoked by stimulation of muscle and cutaneous afferents.

    PubMed

    Gelsema, A J; Bouman, L N; Karemaker, J M

    1985-04-01

    The short-latency effect on heart rate of peripheral nerve stimulation was studied in decerebrate cats. Selective activation (17-40 microA, 100 Hz, 1 s long) of low-threshold fibers in the nerves to the triceps surae muscle yielded isometric contractions of maximal force that were accompanied by a cardiac cycle length shortening within 0.4 s from the start of stimulation. This effect was abolished by pharmacologically induced neuromuscular blockade. The cardiac cycle length shortening during paralysis reappeared after a 6- to 10-fold increase of the stimulation strength. Cutaneous (sural) nerve stimulation (15-25 microA, 100 Hz, 1 s long) elicited reflex contractions in the stimulated limb, which were also accompanied by a cardiac acceleration with similar latency. Paralysis prevented the reflex contractions and reduced the cardiac response in some cats and abolished it in others. The response reappeared in either case after a 5- to 10-fold increase of the stimulus strength. It is concluded that muscle nerve and cutaneous nerve activity both cause a similar cardiac acceleration with a latency of less than 0.4 s. The response to muscle nerve stimulation is elicited by activity in group III afferents. It is excluded that the cardiac response to nerve stimulation is secondary to a change in the respiratory pattern.

  14. Some electrical properties of the rabbit anococcygeus muscle and a comparison of the effects of inhibitory nerve stimulation in the rat and rabbit

    PubMed Central

    Creed, Kate E.; Gillespie, J. S.

    1977-01-01

    1. Simultaneous recordings of mechanical activity and membrane potential of individual smooth muscle cells have been made in the rabbit anococcygeus muscle and the effect of field stimulation on these examined. 2. In the absence of tone the mean resting membrane potential was - 48 mV. In the stretched muscle spontaneous tone and rhythmic activity quite frequently appeared and this was associated with depolarization of the muscle cells. 3. The response to field stimulation depended on the frequency of stimulation, the level of membrane potential and the presence of myogenic tone. The usual response to single pulses or low frequency stimulation was a hyperpolarization of up to 30 mV (mean 14±6·8 mV) after a latency of 185 msec and accompanied by muscle relaxation. Higher frequencies (over 8 Hz) produced an initial depolarization often with a spike potential and followed by hyperpolarization. The mechanical response in these instances was contraction or contraction followed by relaxation. At all frequencies rebound depolarization and an associated contraction followed the end of stimulation). 4. Phentolamine (5×10-6 M) and guanethidine (10-6 M) blocked the initial depolarization and contraction but had no effect on hyperpolarization, muscle relaxation or rebound depolarization and contraction. 5. The effect of field stimulation in the presence of guanethidine (4×10-5 M) was re-examined in the rat anococcygeus. Single pulses were ineffective, repetitive stimulation produced muscle relaxation but no hyperpolarization comparable to the rabbit. Any oscillations in membrane potential were damped during field stimulation and sometimes a small hyperpolarization was produced with a maximum amplitude of 13 mV and a mean of 1·9±1·2 mV. 6. The transmembrane potential at the peak of hyperpolarization in the rabbit was rarely more than -70 mV. Passive displacement of the membrane potential by current pulses altered the amplitude of the hyperpolarization and suggested that

  15. Assessing viability of extracorporeal preserved muscle transplants using external field stimulation: a novel tool to improve methods prolonging bridge-to-transplantation time

    NASA Astrophysics Data System (ADS)

    Taeger, Christian D.; Friedrich, Oliver; Dragu, Adrian; Weigand, Annika; Hobe, Frieder; Drechsler, Caroline; Geppert, Carol I.; Arkudas, Andreas; Münch, Frank; Buchholz, Rainer; Pollmann, Charlotte; Schramm, Axel; Birkholz, Torsten; Horch, Raymund E.; Präbst, Konstantin

    2015-07-01

    Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation. Perfusion protocols have been established for a variety of applications and proven to be superior to procedures used in clinical routine. Extracorporeal perfusion of muscle tissue though cumbersome is highly desirable since it is highly susceptible to ischemia-related damage. To show the efficacy of different perfusion protocols external field stimulation can be used to immediately visualize improvement or deterioration of the tissue during active and running perfusion protocols. This method has been used to show the superiority of extracorporeal perfusion using porcine rectus abdominis muscles perfused with heparinized saline solution. Perfused muscles showed statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. The combination of extracorporeal perfusion and external field stimulation may improve organ conservation research.

  16. Assessing viability of extracorporeal preserved muscle transplants using external field stimulation: a novel tool to improve methods prolonging bridge-to-transplantation time

    PubMed Central

    Taeger, Christian D.; Friedrich, Oliver; Dragu, Adrian; Weigand, Annika; Hobe, Frieder; Drechsler, Caroline; Geppert, Carol I.; Arkudas, Andreas; Münch, Frank; Buchholz, Rainer; Pollmann, Charlotte; Schramm, Axel; Birkholz, Torsten; Horch, Raymund E.; Präbst, Konstantin

    2015-01-01

    Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation. Perfusion protocols have been established for a variety of applications and proven to be superior to procedures used in clinical routine. Extracorporeal perfusion of muscle tissue though cumbersome is highly desirable since it is highly susceptible to ischemia-related damage. To show the efficacy of different perfusion protocols external field stimulation can be used to immediately visualize improvement or deterioration of the tissue during active and running perfusion protocols. This method has been used to show the superiority of extracorporeal perfusion using porcine rectus abdominis muscles perfused with heparinized saline solution. Perfused muscles showed statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. The combination of extracorporeal perfusion and external field stimulation may improve organ conservation research. PMID:26145230

  17. Comparison of swim recovery and muscle stimulation on lactate removal after sprint swimming.

    PubMed

    Neric, Francis B; Beam, William C; Brown, Lee E; Wiersma, Lenny D

    2009-12-01

    Competitive swimming requires multiple bouts of high-intensity exercise, leading to elevated blood lactate. Active exercise recovery has been shown to lower lactate faster than passive resting recovery but may not always be practical. An alternative treatment, electrical muscle stimulation, may have benefits similar to active recovery in lowering blood lactate but to date is unstudied. Therefore, this study compared submaximal swimming and electrical muscle stimulation in reducing blood lactate after sprint swimming. Thirty competitive swimmers (19 men and 11 women) participated in the study. Each subject completed 3 testing sessions consisting of a warm-up swim, a 200-yard maximal frontcrawl sprint, and 1 of 3 20-minute recovery treatments administered in random order. The recovery treatments consisted of a passive resting recovery, a submaximal swimming recovery, or electrical muscle stimulation. Blood lactate was tested at baseline, after the 200-yard sprint, and after 10 and 20 minutes of recovery. A significant interaction (p < 0.05) between recovery treatment and recovery time was observed. Blood lactate levels for the swimming recovery were significantly lower at 10 minutes (3.50 +/- 1.57 mmol.L-1) and 20 minutes (1.60 +/- 0.57 mmol.L-1) of recovery than either of the other 2 treatments. Electrical muscle stimulation led to a lower mean blood lactate (3.12 +/- 1.41 mmol.L-1) after 20 minutes of recovery compared with passive rest (4.11 +/- 1.35 mmol.L-1). Submaximal swimming proved to be most effective at lowering blood lactate, but electrical muscle stimulation also reduced blood lactate 20 minutes postexercise significantly better than resting passive recovery. Electrical muscle stimulation shows promise as an alternate recovery treatment for the purpose of lowering blood lactate.

  18. Transcutaneous neuromuscular electrical stimulation: influence of electrode positioning and stimulus amplitude settings on muscle response.

    PubMed

    Gobbo, M; Gaffurini, P; Bissolotti, L; Esposito, F; Orizio, C

    2011-10-01

    The aim of the study was to investigate the influence of two different transcutaneous neuromuscular electrical stimulation procedures on evoked muscle torque and local tissue oxygenation. In the first one (MP mode), the cathode was facing the muscle main motor point and stimulus amplitude was set to the level eliciting the maximal myoelectrical activation according to the amplitude of the evoked electromyogram (EMG); in the second one (RC mode), the electrodes were positioned following common reference charts for electrode placement while stimulus amplitude was set according to subject tolerance. Tibialis Anterior (TA) and Vastus Lateralis (VL) muscles of 10 subjects (28.4 ± 8.2 years) were tested in specific dynamometers to measure the evoked isometric torque. The EMG and near-infrared spectroscopy probes were placed on muscle belly to detect the electrical activity and local metabolic modifications of the stimulated muscle, respectively. The stimulation protocol consisted of a gradually increasing frequency ramp from 2 to 50 Hz in 7.5 s. Compared to RC mode, in MP mode the contractile parameters (peak twitch, tetanic torque, area under the torque build-up) and the metabolic solicitation (oxygen consumption and hyperemia due to metabolites accumulation) resulted significantly higher for both TA and VL muscles. MP mode resulted also to be more comfortable for the subjects. Based on the assumption that proper mechanical and metabolic stimuli are necessary to induce muscle strengthening, our results witness the importance of an optimized, i.e., comfortable and effective, stimulation to promote the aforementioned muscle adaptive modifications.

  19. Metabolic acidosis stimulates protein degradation in rat muscle by a glucocorticoid-dependent mechanism.

    PubMed Central

    May, R C; Kelly, R A; Mitch, W E

    1986-01-01

    Metabolic acidosis is associated with enhanced renal ammonia-genesis which is regulated, in part, by glucocorticoids. The interaction between glucocorticoids and chronic metabolic acidosis on nitrogen utilization and muscle protein metabolism is unknown. In rats pair-fed by gavage, we found that chronic acidosis stunted growth and caused a 43% increase in urinary nitrogen and an 87% increase in urinary corticosterone. Net protein degradation in incubated epitrochlearis muscles from chronically acidotic rats was stimulated at all concentrations of insulin from 0 to 10(4) microU/ml. This effect of acidosis persisted despite supplementation of the media with amino acids with or without insulin, indomethacin, and inhibitors of lysosomal thiol cathepsins. Acidosis did not change protein synthesis; hence, the increase in net protein degradation was caused by stimulation of proteolysis. Acidosis did not increase glutamine production in muscle. The protein catabolic effect of acidosis required glucocorticoids; protein degradation was stimulated in muscle of acidotic, adrenalectomized rats only if they were treated with dexamethasone. Moreover, when nonacidotic animals were given 3 micrograms/100 g of body weight dexamethasone twice a day, muscle protein degradation was increased if the muscles were simply incubated in acidified media. We conclude that chronic metabolic acidosis depresses nitrogen utilization and increases glucocorticoid production. The combination of increased glucocorticoids and acidosis stimulates muscle proteolysis but does not affect protein synthesis. These changes in muscle protein metabolism may play a role in the defense against acidosis by providing amino acid nitrogen to support the glutamine production necessary for renal ammoniagenesis. PMID:3511100

  20. Nonmyogenic cells in skeletal muscle regeneration.

    PubMed

    Paylor, Ben; Natarajan, Anuradha; Zhang, Regan-Heng; Rossi, Fabio

    2011-01-01

    Although classical dogma dictates that satellite cells are the primary cell type involved in skeletal muscle regeneration, alternative cell types such as a variety of inflammatory and stromal cells are also actively involved in this process. A model describing myogenic cells as direct contributors to regeneration and nonmyogenic cells from other developmental sources as important accessories has emerged, with similar systems having been described in numerous other tissues in the body. Increasing evidence supports the notion that inflammatory cells function as supportive accessory cells, and are not merely involved in clearing damage following skeletal muscle injury. Additionally, recent studies have highlighted the role of tissue resident mesenchymal cell populations as playing a central role in regulating regeneration. These "accessory" cell populations are proposed to influence myogenesis via direct cell contact and secretion of paracrine trophic factors. The basic foundations of accessory cell understanding should be recognized as a crucial component to all prospects of regenerative medicine, and this chapter intends to provide a comprehensive background on the current literature describing immune and tissue-resident mesenchymal cells' role in skeletal muscle regeneration.

  1. Satellite Cells and the Muscle Stem Cell Niche

    PubMed Central

    Yin, Hang; Price, Feodor

    2013-01-01

    Adult skeletal muscle in mammals is a stable tissue under normal circumstances but has remarkable ability to repair after injury. Skeletal muscle regeneration is a highly orchestrated process involving the activation of various cellular and molecular responses. As skeletal muscle stem cells, satellite cells play an indispensible role in this process. The self-renewing proliferation of satellite cells not only maintains the stem cell population but also provides numerous myogenic cells, which proliferate, differentiate, fuse, and lead to new myofiber formation and reconstitution of a functional contractile apparatus. The complex behavior of satellite cells during skeletal muscle regeneration is tightly regulated through the dynamic interplay between intrinsic factors within satellite cells and extrinsic factors constituting the muscle stem cell niche/microenvironment. For the last half century, the advance of molecular biology, cell biology, and genetics has greatly improved our understanding of skeletal muscle biology. Here, we review some recent advances, with focuses on functions of satellite cells and their niche during the process of skeletal muscle regeneration. PMID:23303905

  2. NEUROMUSCULAR ELECTRICAL STIMULATION OF THE HINDLIMB MUSCLES FOR MOVEMENT THERAPY IN A RODENT MODEL

    PubMed Central

    Ichihara, Kazuhiko; Venkatasubramanian, Ganapriya; Abbas, James J.; Jung, Ranu

    2009-01-01

    Neuromuscular electrical stimulation (NMES) can provide functional movements in people after central nervous system injury. The neuroplastic effects of long-term NMES induced repetitive limb movement are not well understood. A rodent model of neurotrauma in which NMES can be implemented may be effective for such investigations. We present a rodent model for NMES of the flexor and extensor muscles of the hip, knee, and ankle hindlimb muscles. Custom fabricated intramuscular stimulating electrodes for rodents were implanted near identified motor points of targeted muscles in ten adult, female Long Evans rats. The effects of altering NMES pulse stimulation parameters were characterized using strength duration curves, isometric joint torque recruitment curves and joint angle measures. The data indicate that short pulse widths have the advantage of producing graded torque recruitment curves when current is used as the control parameter. A stimulus frequency of 75Hz or more produces fused contractions. The data demonstrate ability to accurately implant the electrodes and obtain selective, graded, repeatable, strong muscle contractions. Knee and ankle angular excursions comparable to those obtained in normal treadmill walking in the same rodent species can be obtained by stimulating the target muscles. Joint torques (normalized to body weight) obtained were larger than those reported in the literature for small tailed therian mammals and for peak isometric ankle plantarflexion in a different rodent species. This model system could be used for investigations of NMES assisted hindlimb movement therapy. PMID:18848960

  3. Probability-based prediction of activity in multiple arm muscles: implications for functional electrical stimulation.

    PubMed

    Anderson, Chad V; Fuglevand, Andrew J

    2008-07-01

    Functional electrical stimulation (FES) involves artificial activation of muscles with implanted electrodes to restore motor function in paralyzed individuals. The range of motor behaviors that can be generated by FES, however, is limited to a small set of preprogrammed movements such as hand grasp and release. A broader range of movements has not been implemented because of the substantial difficulty associated with identifying the patterns of muscle stimulation needed to elicit specified movements. To overcome this limitation in controlling FES systems, we used probabilistic methods to estimate the levels of muscle activity in the human arm during a wide range of free movements based on kinematic information of the upper limb. Conditional probability distributions were generated based on hand kinematics and associated surface electromyographic (EMG) signals from 12 arm muscles recorded during a training task involving random movements of the arm in one subject. These distributions were then used to predict in four other subjects the patterns of muscle activity associated with eight different movement tasks. On average, about 40% of the variance in the actual EMG signals could be accounted for in the predicted EMG signals. These results suggest that probabilistic methods ultimately might be used to predict the patterns of muscle stimulation needed to produce a wide array of desired movements in paralyzed individuals with FES.

  4. Cutaneous Recording and Stimulation of Muscles Using Organic Electronic Textiles.

    PubMed

    Papaiordanidou, Maria; Takamatsu, Seiichi; Rezaei-Mazinani, Shahab; Lonjaret, Thomas; Martin, Alain; Ismailova, Esma

    2016-08-01

    Electronic textiles are an emerging field providing novel and non-intrusive solutions for healthcare. Conducting polymer-coated textiles enable a new generation of fully organic surface electrodes for electrophysiological evaluations. Textile electrodes are able to assess high quality muscular monitoring and to perform transcutaneous electrical stimulation.

  5. Alteration of Muscle Function After Electrical Stimulation Bout of Knee Extensors and Flexors

    PubMed Central

    Vanderthommen, Marc; Triffaux, Mylène; Demoulin, Christophe; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2012-01-01

    The purpose was to study the effects on muscle function of an electrical stimulation bout applied unilaterally on thigh muscles in healthy male volunteers. One group (ES group, n = 10) received consecutively 100 isometric contractions of quadriceps and 100 isometric contractions of hamstrings (on-off ratio 6-6 s) induced by neuromuscular electrical stimulations (NMES). Changes in muscle torque, muscle soreness (0-10 VAS), muscle stiffness and serum creatine kinase (CK) activity were assessed before the NMES exercise (pre-ex) as well as 24h (d+1), 48h (d+2) and 120h (d+5) after the bout. A second group (control group, n = 10) were submitted to the same test battery than the ES group and with the same time-frame. The between-group comparison indicated a significant increase in VAS scores and in serum levels of CK only in the ES group. In the ES group, changes were more pronounced in hamstrings than in quadriceps and peaked at d+2 (quadriceps VAS scores = 2.20 ± 1.55 a.u. (0 at pre-ex); hamstrings VAS scores = 3.15 ± 2.14 a.u. (0 at pre-ex); hip flexion angle = 62 ± 5° (75 ± 6° at pre-ex); CK activity = 3021 ± 2693 IU·l-1 (136 ± 50 IU·l-1 at pre-ex)). The results of the present study suggested the occurrence of muscle damage that could have been induced by the peculiar muscle recruitment in NMES and the resulting overrated mechanical stress. The sensitivity to the damaging effects of NMES appeared higher in the hamstrings than in quadriceps muscles. Key points A stimulation bout of quadriceps and hamstrings that reflects usual application of NMES, increases indirect markers of muscle damage (muscle soreness, muscle weakness and stiffness and serum CK activity). The occurrence of muscle damage could have been induced by the peculiar muscle recruitment in NMES and the resulting overrated mechanical stress. The sensitivity to the damaging effects of NMES appears higher in the hamstrings than in quadriceps muscles. PMID:24150067

  6. Effect of neuromuscular electrical stimulation on facial muscle strength and oral function in stroke patients with facial palsy

    PubMed Central

    Choi, Jong-Bae

    2016-01-01

    [Purpose] The aim of this study was to investigate the effect of neuromuscular electrical stimulation on facial muscle strength and oral function in stroke patients with facial palsy. [Subjects and Methods] Nine subjects received the electrical stimulation and traditional dysphagia therapy. Electrical stimulation was applied to stimulate each subject’s facial muscles 30 minutes a day, 5 days a week, for 4 weeks. [Results] Subjects showed significant improvement in cheek and lip strength and oral function after the intervention. [Conclusion] This study demonstrates that electrical stimulation improves facial muscle strength and oral function in stroke patients with dysphagia. PMID:27799689

  7. Stimulation of incretin secreting cells

    PubMed Central

    Pais, Ramona; Gribble, Fiona M.; Reimann, Frank

    2016-01-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation. PMID:26885360

  8. Glass Probe Stimulation of Hair Cell Stereocilia.

    PubMed

    Peng, Anthony W; Ricci, Anthony J

    2016-01-01

    Hair cells are designed to sense mechanical stimuli of sound using their apical stereocilia hair bundles. Mechanical deflection of this hair bundle is converted into an electrical signal through gating of mechano-electric transduction channels. Stiff probe stimulation of hair bundles is an invaluable tool for studying the transduction channel and its associated processes because of the speed and ability to precisely control hair bundle position. Proper construction of these devices is critical to their ultimate performance as is appropriate placement of the probe onto the hair bundle. Here we describe the construction and use of a glass probe coupled to a piezo-electric actuator for stimulating hair bundles, including the basic technique for positioning of the stimulating probe onto the hair bundle. These piezo-electric stimulators can be adapted to other mechanically sensitive systems.

  9. Exogenous amino acids stimulate net muscle protein synthesis in the elderly.

    PubMed Central

    Volpi, E; Ferrando, A A; Yeckel, C W; Tipton, K D; Wolfe, R R

    1998-01-01

    We have investigated the response of amino acid transport and protein synthesis in healthy elderly individuals (age 71+/-2 yr) to the stimulatory effect of increased amino acid availability. Muscle protein synthesis and breakdown, and amino acid transport were measured in the postabsorptive state and during the intravenous infusion of an amino acid mixture. Muscle-free amino acid kinetics were calculated by means of a three compartment model using data obtained by femoral arterio-venous catheterization and muscle biopsies from the vastus lateralis during the infusion of stable isotope tracers of amino acids. In addition, muscle protein fractional synthetic rate (FSR) was measured. Peripheral amino acid infusion significantly increased amino acid delivery to the leg, amino acid transport, and muscle protein synthesis when measured either with the three compartment model (P < 0.05) or with the traditional precursor-product approach (FSR increased from 0. 0474+/-0.0054 to 0.0940+/-0.0143%/h, P < 0.05). Because protein breakdown did not change during amino acid infusion, a positive net balance of amino acids across the muscle was achieved. We conclude that, although muscle mass is decreased in the elderly, muscle protein anabolism can nonetheless be stimulated by increased amino acid availability. We thus hypothesize that muscle mass could be better maintained with an increased intake of protein or amino acids. PMID:9576765

  10. Hamster thecal cells express muscle characteristics

    SciTech Connect

    Self, D.A.; Schroeder, P.C.; Gown, A.M.

    1988-08-01

    Contraction of the follicular wall about the time of ovulation appears to be a coordinated event; however, the cells that mediate it remain poorly studied. We examined the theca externa cells in the wall of hamster follicles for the presence of a functional actomyosin system, both in developing follicles and in culture. We used a monoclonal antibody (HHF35) that recognizes the alpha and gamma isoelectric variants of actin normally found in muscle, but not the beta variant associated with non-muscle sources, to evaluate large preovulatory follicles for actin content and composition. Antibody staining of sectioned ovaries showed intense circumferential reactivity in the outermost wall of developing follicles. Immunoblots from two-dimensional gels of theca externa lysates demonstrated the presence of the two muscle-specific isozymes of actin. Immunofluorescence of cultured follicular cells pulse-labeled with (3H) thymidine (for autoradiographic detection of DNA replication) revealed the presence, in many dividing cells, of actin filaments aligned primarily along the longitudinal axis of the cells. In cultures exposed to the calcium ionophore A23187 (10(-4) M) for varying periods (5 min to 1 h), contraction of many individual muscle-actin-positive cells was observed. Immunofluorescence of these cells, fixed immediately after ionophore-induced contraction, revealed compaction of the actin filaments. Our findings demonstrate that the cells of the theca externa contain muscle actins from an early stage and that these cells are capable of contraction even while proliferating in subconfluent cultures. They suggest that follicular growth may include a naturally occurring developmental sequence in which a contractile cell type proliferates in the differentiated state.

  11. Reflex inhibition of normal cramp following electrical stimulation of the muscle tendon.

    PubMed

    Khan, Serajul I; Burne, John A

    2007-09-01

    Muscle cramp was induced in one head of the gastrocnemius muscle (GA) in eight of thirteen subjects using maximum voluntary contraction when the muscle was in the shortened position. Cramp in GA was painful, involuntary, and localized. Induction of cramp was indicated by the presence of electromyographic (EMG) activity in one head of GA while the other head remained silent. In all cramping subjects, reflex inhibition of cramp electrical activity was observed following Achilles tendon electrical stimulation and they all reported subjective relief of cramp. Thus muscle cramp can be inhibited by stimulation of tendon afferents in the cramped muscle. When the inhibition of cramp-generated EMG and voluntary EMG was compared at similar mean EMG levels, the area and timing of the two phases of inhibition (I(1), I(2)) did not differ significantly. This strongly suggests that the same reflex pathway was the source of the inhibition in both cases. Thus the cramp-generated EMG is also likely to be driven by spinal synaptic input to the motorneurons. We have found that the muscle conditions that appear necessary to facilitate cramp, a near to maximal contraction of the shortened muscle, are also the conditions that render the inhibition generated by tendon afferents ineffective. When the strength of tendon inhibition in cramping subjects was compared with that in subjects that failed to cramp, it was found to be significantly weaker under the same experimental conditions. It is likely that reduced inhibitory feedback from tendon afferents has an important role in generating cramp.

  12. A novel insulin sensitizer (S15511) enhances insulin-stimulated glucose uptake in rat skeletal muscles.

    PubMed

    Jessen, N; Selmer Buhl, E; Pold, R; Schmitz, O; Lund, S

    2008-04-01

    Type 2 diabetes is preceded by the presence of skeletal muscle insulin resistance, and drugs that increase insulin sensitivity in skeletal muscle prevent the disease. S15511 is an original compound with demonstrated effects on insulin sensitivity in animal models of insulin resistance. However, the mechanisms behind the insulin-sensitizing effect of S15511 are unknown. The aim of our study was to explore whether S15511 improves insulin sensitivity in skeletal muscles. Insulin sensitivity was assessed in skeletal muscles from S15511-treated rats by measuring intracellular insulin-signaling activity and insulin-stimulated glucose transport in isolated muscles. In addition, GLUT4 expression and glycogen levels were assessed after treatment. S15511 treatment was associated with an increase in insulin-stimulated glucose transport in type IIb fibers, while type I fibers were unaffected. The enhanced glucose transport was mirrored by a fiber type-specific increase in GLUT4 expression, while no improvement in insulin-signaling activity was observed. S15511 is a novel insulin sensitizer that is capable of improving glucose homeostasis in nondiabetic rats. The compound enhances skeletal muscle insulin sensitivity and specifically targets type IIb muscle fibers by increasing GLUT4 expression. Together these data show S15511 to be a potentially promising new drug in the treatment and prevention of type 2 diabetes.

  13. Extracellular matrix components direct porcine muscle stem cell behavior

    SciTech Connect

    Wilschut, Karlijn J.; Haagsman, Henk P.; Roelen, Bernard A.J.

    2010-02-01

    In muscle tissue, extracellular matrix proteins, together with the vasculature system, muscle-residence cells and muscle fibers, create the niche for muscle stem cells. The niche is important in controlling proliferation and directing differentiation of muscle stem cells to sustain muscle tissue. Mimicking the extracellular muscle environment improves tools exploring the behavior of primary muscle cells. Optimizing cell culture conditions to maintain muscle commitment is important in stem cell-based studies concerning toxicology screening, ex vivo skeletal muscle tissue engineering and in the enhancement of clinical efficiency. We used the muscle extracellular matrix proteins collagen type I, fibronectin, laminin, and also gelatin and Matrigel as surface coatings of tissue culture plastic to resemble the muscle extracellular matrix. Several important factors that determine myogenic commitment of the primary muscle cells were characterized by quantitative real-time RT-PCR and immunofluorescence. Adhesion of high PAX7 expressing satellite cells was improved if the cells were cultured on fibronectin or laminin coatings. Cells cultured on Matrigel and laminin coatings showed dominant integrin expression levels and exhibited an activated Wnt pathway. Under these conditions both stem cell proliferation and myogenic differentiation capacity were superior if compared to cells cultured on collagen type I, fibronectin and gelatin. In conclusion, Matrigel and laminin are the preferred coatings to sustain the proliferation and myogenic differentiation capacity of the primary porcine muscle stem cells, when cells are removed from their natural environment for in vitro culture.

  14. Potential of M-Wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation for Motor Rehabilitation

    PubMed Central

    Miura, Naoto; Watanabe, Takashi

    2016-01-01

    Clinical studies on application of functional electrical stimulation (FES) to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between electrical stimulations help recovery of muscle activation level. In this paper, M-waves elicited by double pulses were examined in muscle fatigue evaluation during repetitive movements considering rehabilitation training with surface electrical stimulation. M-waves were measured under the two conditions of repetitive stimulation: knee extension force production under the isometric condition and the dynamic movement condition by knee joint angle control. Amplitude of M-wave elicited by the 2nd pulse of a double pulse decreased during muscle fatigue in both measurement conditions, while the change in M-waves elicited by single pulses in a stimulation burst was not relevant to muscle fatigue in repeated activation with stimulation interval of 1 s. Fatigue index obtained from M-waves elicited by 2nd pulses was suggested to provide good estimation of muscle fatigue during repetitive movements with FES. PMID:27110556

  15. Potential of M-Wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation for Motor Rehabilitation.

    PubMed

    Miura, Naoto; Watanabe, Takashi

    2016-01-01

    Clinical studies on application of functional electrical stimulation (FES) to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between electrical stimulations help recovery of muscle activation level. In this paper, M-waves elicited by double pulses were examined in muscle fatigue evaluation during repetitive movements considering rehabilitation training with surface electrical stimulation. M-waves were measured under the two conditions of repetitive stimulation: knee extension force production under the isometric condition and the dynamic movement condition by knee joint angle control. Amplitude of M-wave elicited by the 2nd pulse of a double pulse decreased during muscle fatigue in both measurement conditions, while the change in M-waves elicited by single pulses in a stimulation burst was not relevant to muscle fatigue in repeated activation with stimulation interval of 1 s. Fatigue index obtained from M-waves elicited by 2nd pulses was suggested to provide good estimation of muscle fatigue during repetitive movements with FES.

  16. Effect of neuromuscular electrical stimulation on motor cortex excitability upon release of tonic muscle contraction.

    PubMed

    Sugawara, Kenichi; Tanabe, Shigeo; Suzuki, Tomotaka; Higashi, Toshio

    The aim of the present study was to investigate the neurophysiological triggers underlying muscle relaxation from the contracted state, and to examine the mechanisms involved in this process and their subsequent modification by neuromuscular electrical stimulation (NMES). Single-pulse transcranial magnetic stimulation (TMS) was used to produce motor-evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) in 23 healthy participants, wherein motor cortex excitability was examined at the onset of voluntary muscle relaxation following a period of voluntary tonic muscle contraction. In addition, the effects of afferent input on motor cortex excitability, as produced by NMES during muscle contraction, were examined. In particular, two NMES intensities were used for analysis: 1.2 times the sensory threshold and 1.2 times the motor threshold (MT). Participants were directed to execute constant wrist extensions and to release muscle contraction in response to an auditory "GO" signal. MEPs were recorded from the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles, and TMS was applied at three different time intervals (30, 60, and 90 ms) after the "GO" signal. Motor cortex excitability was greater during voluntary ECR and FCR relaxation using high-intensity NMES, and relaxation time was decreased. Each parameter differed significantly between 30 and 60 ms. Moreover, in both muscles, SICI was larger in the presence than in the absence of NMES. Therefore, the present findings suggest that terminating a muscle contraction triggers transient neurophysiological mechanisms that facilitate the NMES-induced modulation of cortical motor excitability in the period prior to muscle relaxation. High-intensity NMES might facilitate motor cortical excitability as a function of increased inhibitory intracortical activity, and therefore serve as a transient trigger for the relaxation of prime mover muscles in a therapeutic context.

  17. The emergence of Pax7-expressing muscle stem cells during vertebrate head muscle development

    PubMed Central

    Nogueira, Julia Meireles; Hawrot, Katarzyna; Sharpe, Colin; Noble, Anna; Wood, William M.; Jorge, Erika C.; Goldhamer, David J.; Kardon, Gabrielle; Dietrich, Susanne

    2015-01-01

    Pax7 expressing muscle stem cells accompany all skeletal muscles in the body and in healthy individuals, efficiently repair muscle after injury. Currently, the in vitro manipulation and culture of these cells is still in its infancy, yet muscle stem cells may be the most promising route toward the therapy of muscle diseases such as muscular dystrophies. It is often overlooked that muscular dystrophies affect head and body skeletal muscle differently. Moreover, these muscles develop differently. Specifically, head muscle and its stem cells develop from the non-somitic head mesoderm which also has cardiac competence. To which extent head muscle stem cells retain properties of the early head mesoderm and might even be able to switch between a skeletal muscle and cardiac fate is not known. This is due to the fact that the timing and mechanisms underlying head muscle stem cell development are still obscure. Consequently, it is not clear at which time point one should compare the properties of head mesodermal cells and head muscle stem cells. To shed light on this, we traced the emergence of head muscle stem cells in the key vertebrate models for myogenesis, chicken, mouse, frog and zebrafish, using Pax7 as key marker. Our study reveals a common theme of head muscle stem cell development that is quite different from the trunk. Unlike trunk muscle stem cells, head muscle stem cells do not have a previous history of Pax7 expression, instead Pax7 expression emerges de-novo. The cells develop late, and well after the head mesoderm has committed to myogenesis. We propose that this unique mechanism of muscle stem cell development is a legacy of the evolutionary history of the chordate head mesoderm. PMID:26042028

  18. Transdifferentiation of human endothelial progenitors into smooth muscle cells.

    PubMed

    Ji, HaYeun; Atchison, Leigh; Chen, Zaozao; Chakraborty, Syandan; Jung, Youngmee; Truskey, George A; Christoforou, Nicolas; Leong, Kam W

    2016-04-01

    Access to smooth muscle cells (SMC) would create opportunities for tissue engineering, drug testing, and disease modeling. Herein we report the direct conversion of human endothelial progenitor cells (EPC) to induced smooth muscle cells (iSMC) by induced expression of MYOCD. The EPC undergo a cytoskeletal rearrangement resembling that of mesenchymal cells within 3 days post initiation of MYOCD expression. By day 7, the reprogrammed cells show upregulation of smooth muscle markers ACTA2, MYH11, and TAGLN by qRT-PCR and ACTA2 and MYH11 expression by immunofluorescence. By two weeks, they resemble umbilical artery SMC in microarray gene expression analysis. The iSMC, in contrast to EPC control, show calcium transients in response to phenylephrine stimulation and a contractility an order of magnitude higher than that of EPC as determined by traction force microscopy. Tissue-engineered blood vessels constructed using iSMC show functionality with respect to flow- and drug-mediated vasodilation and vasoconstriction.

  19. Pairing Voluntary Movement and Muscle-Located Electrical Stimulation Increases Cortical Excitability

    PubMed Central

    Jochumsen, Mads; Niazi, Imran K.; Signal, Nada; Nedergaard, Rasmus W.; Holt, Kelly; Haavik, Heidi; Taylor, Denise

    2016-01-01

    Learning new motor skills has been correlated with increased cortical excitability. In this study, different location of electrical stimulation (ES), nerve, or muscle, was paired with voluntary movement to investigate if ES paired with voluntary movement (a) would increase the excitability of cortical projections to tibialis anterior and (b) if stimulation location mattered. Cortical excitability changes were quantified using motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) at varying intensities during four conditions. Twelve healthy subjects performed 50 dorsiflexions at the ankle during nerve or muscle ES at motor threshold (MTh). ES alone was delivered 50 times and the movement was performed 50 times. A significant increase in the excitability from pre- to post-intervention (P = 0.0061) and pre- to 30 min post-intervention (P = 0.017) measurements was observed when voluntary movement was paired with muscle ES located at tibialis anterior. An increase of 50 ± 57 and 28 ± 54% in the maximum MEPs was obtained for voluntary movement paired with muscle-located and nerve-located ES, respectively. The maximum MEPs for voluntary movement alone and muscle-located ES alone were −5 ± 28 and 2 ± 42%, respectively. Pairing voluntary movement with muscle-located ES increases excitability of corticospinal projections of tibialis anterior in healthy participants. This finding suggests that active participation during muscle-located ES protocols increases cortical excitability to a greater extent than stimulation alone. The next stage of this research is to investigate the effect in people with stroke. The results may have implications for motor recovery in patients with motor impairments following neurological injury. PMID:27733823

  20. AICAR stimulation metabolome widely mimics electrical contraction in isolated rat epitrochlearis muscle.

    PubMed

    Miyamoto, Licht; Egawa, Tatsuro; Oshima, Rieko; Kurogi, Eriko; Tomida, Yosuke; Tsuchiya, Koichiro; Hayashi, Tatsuya

    2013-12-15

    Physical exercise has potent therapeutic and preventive effects against metabolic disorders. A number of studies have suggested that 5'-AMP-activated protein kinase (AMPK) plays a pivotal role in regulating carbohydrate and lipid metabolism in contracting skeletal muscles, while several genetically manipulated animal models revealed the significance of AMPK-independent pathways. To elucidate significance of AMPK and AMPK-independent signals in contracting skeletal muscles, we conducted a metabolomic analysis that compared the metabolic effects of 5-aminoimidazole-4-carboxamide-1-β-D-ribonucleoside (AICAR) stimulation with the electrical contraction ex vivo in isolated rat epitrochlearis muscles, in which both α1- and α2-isoforms of AMPK and glucose uptake were equally activated. The metabolomic analysis using capillary electrophoresis time-of-flight mass spectrometry detected 184 peaks and successfully annotated 132 small molecules. AICAR stimulation exhibited high similarity to the electrical contraction in overall metabolites. Principal component analysis (PCA) demonstrated that the major principal component characterized common effects whereas the minor principal component distinguished the difference. PCA and a factor analysis suggested a substantial change in redox status as a result of AMPK activation. We also found a decrease in reduced glutathione levels in both AICAR-stimulated and contracting muscles. The muscle contraction-evoked influences related to the metabolism of amino acids, in particular, aspartate, alanine, or lysine, are supposed to be independent of AMPK activation. Our results substantiate the significance of AMPK activation in contracting skeletal muscles and provide novel evidence that AICAR stimulation closely mimics the metabolomic changes in the contracting skeletal muscles.

  1. Stimulation of post-traumatic regeneration of skeletal muscles of old rats after x-ray irradiation

    SciTech Connect

    Bulyakova, N.V.; Popova, M.F.

    1987-09-01

    The authors seek a method of stimulating restorative processes in irradiated muscles of old animals. Rats were used in the experiments. Different series of experiments were performed, including complete transverse section of the gastrocnemius muscle after local x-ray irradiation, and laser therapy of the transversly divided gastrocnemius muscle. Post-traumatic regeneration of the gastrocnemius muscle of old rats is illustrated schematically. The experimental data showed that pulsed laser therapy or grafting of minced unirradiated muscle tissue can largely restore the regenerative capacity of the gastrocnemius muscle of old rats when depressed by x-ray irradiation, but the method of grafting minced unirradiated muscle tissue was more effective.

  2. The combined influence of stretch, mobility and electrical stimulation in the prevention of muscle fiber atrophy caused hypokinesia and hypodynamia

    NASA Technical Reports Server (NTRS)

    Goldspink, G.; Goldspink, D.; Loughna, P.

    1984-01-01

    The morphological and biochemical changes which occur in the hind limb muscles of the rat in response to hypokinesia and hypodynamia were investigated. Hind limb cast fixation and suspension techniques were employed to study the musclar atrophy after five days of hypokinesia and hypodynamia induced by suspension, appreciable muscular atrophy was apparent, particularly in the anti-gravity muscles. The effect of passive stretching and electrical stimulation on muscle atrophy was studied. Changes in muscle protein mass were assessed with spectrophotometric and radioactive techniques. Passive stretch is shown to counteract muscle disuse atrophy. The change in the numbers of specific muscle fibers in atrophied muscles is discussed.

  3. Restoration of grasp following paralysis through brain-controlled stimulation of muscles.

    PubMed

    Ethier, C; Oby, E R; Bauman, M J; Miller, L E

    2012-05-17

    Patients with spinal cord injury lack the connections between brain and spinal cord circuits that are essential for voluntary movement. Clinical systems that achieve muscle contraction through functional electrical stimulation (FES) have proven to be effective in allowing patients with tetraplegia to regain control of hand movements and to achieve a greater measure of independence in daily activities. In existing clinical systems, the patient uses residual proximal limb movements to trigger pre-programmed stimulation that causes the paralysed muscles to contract, allowing use of one or two basic grasps. Instead, we have developed an FES system in primates that is controlled by recordings made from microelectrodes permanently implanted in the brain. We simulated some of the effects of the paralysis caused by C5 or C6 spinal cord injury by injecting rhesus monkeys with a local anaesthetic to block the median and ulnar nerves at the elbow. Then, using recordings from approximately 100 neurons in the motor cortex, we predicted the intended activity of several of the paralysed muscles, and used these predictions to control the intensity of stimulation of the same muscles. This process essentially bypassed the spinal cord, restoring to the monkeys voluntary control of their paralysed muscles. This achievement is a major advance towards similar restoration of hand function in human patients through brain-controlled FES. We anticipate that in human patients, this neuroprosthesis would allow much more flexible and dexterous use of the hand than is possible with existing FES systems.

  4. Long-term leucine induced stimulation of muscle protein synthesis is amino acid dependent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infusing leucine for 1 h increases skeletal muscle protein synthesis in the neonate, but this is not sustained for 2 h unless the corresponding fall in amino acids is prevented. This study aimed to determine whether a continuous leucine infusion can stimulate protein synthesis for a prolonged period...

  5. Stimulation of muscle protein synthesis by leucine is dependent on plasma amino acid availability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have reported that a physiological increase in plasma leucine increased translation initiation factor activity during 60- and 120-min leucine infusion. Muscle protein synthesis was stimulated at 60 min but not at 120 min, perhaps due to the decrease (-50%) in plasma essential amino acids (AA). ...

  6. Mechanical stimulation in the engineering of heart muscle.

    PubMed

    Liaw, Norman Yu; Zimmermann, Wolfram-Hubertus

    2016-01-15

    Recreating the beating heart in the laboratory continues to be a formidable bioengineering challenge. The fundamental feature of the heart is its pumping action, requiring considerable mechanical forces to compress a blood filled chamber with a defined in- and outlet. Ventricular output crucially depends on venous loading of the ventricles (preload) and on the force generated by the preloaded ventricles to overcome arterial blood pressure (afterload). The rate of contraction is controlled by the spontaneously active sinus node and transmission of its electrical impulses into the ventricles. The underlying principles for these physiological processes are described by the Frank-Starling mechanism and Bowditch phenomenon. It is essential to consider these principles in the design and evaluation of tissue engineered myocardium. This review focuses on current strategies to evoke mechanical loading in hydrogel-based heart muscle engineering.

  7. Amino acids augment muscle protein synthesis in neonatal pigs during acute endotoxemia by stimulating mTOR-dependent translation initiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In skeletal muscle of adults, sepsis reduces protein synthesis by depressing translation initiation and induces resistance to branched-chain amino acid stimulation. Normal neonates maintain a high basal muscle protein synthesis rate that is sensitive to amino acid stimulation. In the present study...

  8. Depolarization-stimulated contractility of gastrointestinal smooth muscle in calcium-free solution: a review.

    PubMed

    Evans, Emily D; Mangel, Allen W

    2011-01-01

    The membrane of most gastrointestinal smooth muscles shows slow waves, slow rhythmic changes in membrane potential. Slow waves serve to bring the membrane potential of smooth muscle cells to a threshold level that elicits a second electrical event known as the spike or action potential. The inward current of the spike, in most gastrointestinal smooth muscle preparations, is carried, at least in part, by calcium. Indeed, considering the narrow diameter of smooth muscle cells, some have hypothesized that the influx of calcium during the spike is sufficient for activation of the contractile machinery. Findings consistent with this include marked reduction in contractility during exposure of muscle segments to blockers of L-type calcium channels or following reductions in external calcium levels. However, it has also been observed that following exposure of muscle segments to external bathing solutions containing no added calcium plus 5 mM EGTA to remove any remaining extracellular calcium, contractions can be triggered following membrane depolarization. It is noteworthy that in isolated smooth muscle cells or in small muscle segments, during incubation in calcium-free solution, depolarization does not induce contractions. The present paper discusses the evidence in support of depolarization-mediated contractions occurring in gastrointestinal smooth muscle segments during incubation in solutions devoid of calcium.

  9. Isolation of satellite cells from single muscle fibers from young, aged, or dystrophic muscles.

    PubMed

    Di Foggia, Valentina; Robson, Lesley

    2012-01-01

    Skeletal muscle contains an identified resident stem cell population called the satellite cells. This cell is responsible for the majority of the postnatal growth and regenerative potential of skeletal muscle. Other cells do contribute to skeletal muscle regeneration and in cultures of minced whole muscle these cells are cultured along with the satellite cells and it is impossible to dissect out their contribution compared to the satellite cells. Therefore, a method to culture pure satellite cells has been developed to study the signaling pathways that control their proliferation and differentiation. In our studies into the role of the resident myogenic stem cells in regeneration, myopathic conditions, and aging, we have optimized the established techniques that already exist to isolate pure satellite cell cultures from single muscle fibers. We have successfully isolated satellite cells from young adults through to 24-month-old muscles and obtained populations of cells that we are studying for the signaling events that regulate their proliferative potential.

  10. Lysyl oxidase propeptide inhibits smooth muscle cell signaling and proliferation

    SciTech Connect

    Hurtado, Paola A.; Vora, Siddharth; Sume, Siddika Selva; Yang, Dan; Hilaire, Cynthia St.; Guo Ying; Palamakumbura, Amitha H.; Schreiber, Barbara M.; Ravid, Katya; Trackman, Philip C.

    2008-02-01

    Lysyl oxidase is required for the normal biosynthesis and maturation of collagen and elastin. It is expressed by vascular smooth muscle cells, and its increased expression has been previously found in atherosclerosis and in models of balloon angioplasty. The lysyl oxidase propeptide (LOX-PP) has more recently been found to have biological activity as a tumor suppressor, and it inhibits Erk1/2 Map kinase activation. We reasoned that LOX-PP may have functions in normal non-transformed cells. We, therefore, investigated its effects on smooth muscle cells, focusing on important biological processes mediated by Erk1/2-dependent signaling pathways including proliferation and matrix metalloproteinase-9 (MMP-9) expression. In addition, we investigated whether evidence for accumulation of LOX-PP could be found in vivo in a femoral artery injury model. Recombinant LOX-PP was expressed and purified, and was found to inhibit primary rat aorta smooth muscle cell proliferation and DNA synthesis by more than 50%. TNF-{alpha}-stimulated MMP-9 expression and Erk1/2 activation were both significantly inhibited by LOX-PP. Immunohistochemistry studies carried out with affinity purified anti-LOX-PP antibody showed that LOX-PP epitopes were expressed at elevated levels in vascular lesions of injured arteries. These novel data suggest that LOX-PP may provide a feedback control mechanism that serves to inhibit properties associated with the development of vascular pathology.

  11. Skeletal muscle stem cells from animals I. Basic cell biology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Skeletal muscle stem cells from food-producing animals have been of interest to agricultural life scientists seeking to develop a better understanding of the molecular regulation of lean tissue (skeletal muscle protein hypertrophy) and intramuscular fat (marbling) development. Enhanced understanding...

  12. Defined electrical stimulation emphasizing excitability for the development and testing of engineered skeletal muscle.

    PubMed

    Khodabukus, Alastair; Baar, Keith

    2012-05-01

    Electrical stimulation is required for the maturation of skeletal muscle and as a way to nondestructively monitor muscle development. However, the wrong stimulation parameters can result in electrochemical damage that impairs muscle development/regeneration. The goal of the current study was to determine what aspect of an electrical impulse, specifically the pulse amplitude or pulse width, was detrimental to engineered muscle function and subsequently how engineered muscle responded to continuous electrical stimulation for 24 h. Acute stimulation at a pulse amplitude greater than six-times rheobase resulted in a 2.4-fold increase in the half-relaxation time (32.3±0.49 ms vs. 77.4±4.35 ms; p<0.05) and a 1.59-fold increase in fatigability (38.2%±3.61% vs. 60.6%±4.52%; p<0.05). No negative effects were observed when the pulse energy was increased by lengthening the pulse width, indicating electrochemical damage was due to electric fields at or above six-times rheobase. Continuous stimulation for 24 h at electric fields greater than 0.5 V/mm consistently resulted in ∼2.5-fold increase in force (0.30±0.04 kN/m² vs. 0.67±0.06 kN/m²; p<0.05). Forty per cent of this increase in force was dependent on the mammalian target of rapamycin (RAP) complex 1 (mTORC1), as RAP prevented this portion of the increase in force (CON=0.30±0.04 kN/m² to 0.67±0.06 kN/m² compared with RAP=0.21±0.01 kN/m² to 0.37±0.04 kN/m²; p<0.05). Since there was no increase in myosin heavy chain, the remaining increase in force over the 24 h of stimulation is likely due to cytoskeletal rearrangement. These data indicate that electrochemical damage occurs in muscle at a voltage field greater than six-times rheobase and therefore optimal muscle stimulation should be performed using lower electric fields (two- to four-times rheobase).

  13. [Selective training of the vastus medialis muscle using electrical stimulator for chondromalacia patella].

    PubMed

    Guo, K; Ye, Q; Lin, J; Shen, J; Yang, X

    1996-04-01

    Chondromalacia patella is closely related with subluxation and tilt of patella, as well as with muscular atrophy of quadriceps, especially in vastus medialis muscle. 364 cases of chondromalacia patella were treated with selective training of the vastus medialis muscle using electrical stimulator in our hospital. 211 cases were followed up after treatment from 6 months to 3 years. Among them excellent and good results were seen in 130 cases (62%), fair results were seen in 69 cases (33%) and no change was seen in 12 cases (5%). Significant reduction of CA (P < 0.01) and LPA (P < 0.001) were observed in all these patients in comparison with their primary angle. We believe that the selective training of the vastus medialis muscle using electrical stimulator is one of the effective methods for the treatment of chondromalacia patella.

  14. Thermal Mechanisms of Millimeter Wave Stimulation of Excitable Cells

    PubMed Central

    Shapiro, Mikhail G.; Priest, Michael F.; Siegel, Peter H.; Bezanilla, Francisco

    2013-01-01

    Interactions between millimeter waves (MMWs) and biological systems have received increasing attention due to the growing use of MMW radiation in technologies ranging from experimental medical devices to telecommunications and airport security. Studies have shown that MMW exposure alters cellular function, especially in neurons and muscles. However, the biophysical mechanisms underlying such effects are still poorly understood. Due to the high aqueous absorbance of MMW, thermal mechanisms are likely. However, nonthermal mechanisms based on resonance effects have also been postulated. We studied MMW stimulation in a simplified preparation comprising Xenopus laevis oocytes expressing proteins that underlie membrane excitability. Using electrophysiological recordings simultaneously with 60 GHz stimulation, we observed changes in the kinetics and activity levels of voltage-gated potassium and sodium channels and a sodium-potassium pump that are consistent with a thermal mechanism. Furthermore, we showed that MMW stimulation significantly increased the action potential firing rate in oocytes coexpressing voltage-gated sodium and potassium channels, as predicted by thermal terms in the Hodgkin-Huxley model of neurons. Our results suggest that MMW stimulation produces significant thermally mediated effects on excitable cells via basic thermodynamic mechanisms that must be taken into account in the study and use of MMW radiation in biological systems. PMID:23790370

  15. A muscle resident cell population promotes fibrosis in hindlimb skeletal muscles of mdx mice through the Wnt canonical pathway.

    PubMed

    Trensz, Frédéric; Haroun, Sonia; Cloutier, Alexandre; Richter, Martin V; Grenier, Guillaume

    2010-11-01

    Previous work has pointed to a role for the Wnt canonical pathway in fibrosis formation in aged skeletal muscles. In the present study, we studied the dystrophic mdx mouse, which displays skeletal muscle fibrosis. Our results indicated that the muscle resident stromal cell (mrSC) population in the muscles of dystrophic mice is higher than in the muscles of age-matched wild-type mice. Wnt3a promoted the proliferation of and collagen expression by cultured mrSCs but arrested the growth of and collagen expression by cultured myoblasts. Injections of Wnt3A in the tibialis anterior muscles of adult wild-type mice significantly enhanced the mrSC population and collagen deposition compared with the contralateral muscles. Conversely, an injection of the Wnt antagonist Dickkof protein (DKK1) into the skeletal muscles of mdx mice significantly reduced collagen deposition. These results suggested that the Wnt canonical pathway expands the population of mrSCs and stimulates their production of collagen as observed during aging and in various myopathies.

  16. Progress toward motor recovery with active neuromuscular stimulation: muscle activation pattern evidence after a stroke.

    PubMed

    Cauraugh, James H; Kim, Sangbum

    2003-03-15

    Chronic cerebrovascular accident individuals with partial paralysis in an upper extremity typically demonstrate difficulty in voluntarily controlling movement initiation. This study investigated patterns of electromyogram (EMG) activation levels while stroke subjects voluntarily initiated their impaired wrist and finger extensor muscles. Twenty subjects were randomly assigned to either a unilateral movement/stimulation group or a bilateral movement/stimulation group. Participants completed 4 days (6 h over 2 weeks) of active neuromuscular stimulation (i.e., 5 s/trial, 90 trials/day, biphasic waveform) on the wrist and finger extensors according to group assignments. The EMG activation levels were analyzed with a three-factor mixed design Motor recovery protocol x Session block x Trial block (2 x 2 x 3) ANOVA with repeated measures on the second and third factors. This robust analysis revealed higher EMG activation levels for the coupled bilateral movement/stimulation group than the unilateral movement/stimulation group. In addition, higher muscle activation levels were found for the second session block as well as trial blocks 2 and 3. Overall, these findings indicated improved motor capabilities of the impaired muscles as evidenced by the higher voluntary EMG activation levels.

  17. Calcium transients in single fibers of low-frequency stimulated fast-twitch muscle of rat.

    PubMed

    Carroll, S; Nicotera, P; Pette, D

    1999-12-01

    Ca(2+) transients were investigated in single fibers isolated from rat extensor digitorum longus muscles exposed to chronic low-frequency stimulation for different time periods up to 10 days. Approximately 2.5-fold increases in resting Ca(2+) concentration ([Ca(2+)]) were observed 2 h after stimulation onset and persisted throughout the stimulation period. The elevated [Ca(2+)] levels were in the range characteristic of slow-twitch fibers from soleus muscle. In addition, we noticed a transitory elevation of the integral [Ca(2+)] per pulse with a maximum ( approximately 5-fold) after 1 day. Steep decreases in rate constant of [Ca(2+)] decay could be explained by an immediate impairment of Ca(2+) uptake and, with longer stimulation periods, by an additional loss of cytosolic Ca(2+) binding capacity resulting from a decay in parvalbumin content. A partial recovery of the rate constant of [Ca(2+)] decay in 10-day stimulated muscle could be explained by an increasing mitochondrial contribution to Ca(2+) sequestration.

  18. Low-frequency stimulation regulates metabolic gene expression in paralyzed muscle

    PubMed Central

    Petrie, Michael; Suneja, Manish

    2015-01-01

    The altered metabolic state after a spinal cord injury compromises systemic glucose regulation. Skeletal muscle atrophies and transforms into fast, glycolytic, and insulin-resistant tissue. Osteoporosis is common after spinal cord injury and limits the ability to exercise paralyzed muscle. We used a novel approach to study the acute effect of two frequencies of stimulation (20 and 5 Hz) on muscle fatigue and gene regulation in people with chronic paralysis. Twelve subjects with chronic (>1 yr) and motor complete spinal cord injury (ASIA A) participated in the study. We assessed the twitch force before and after a single session of electrical stimulation (5 or 20 Hz). We controlled the total number of pulses delivered for each protocol (10,000 pulses). Three hours after the completion of the electrical stimulation (5 or 20 Hz), we sampled the vastus lateralis muscle and examined genes involved with metabolic transcription, glycolysis, oxidative phosphorylation, and mitochondria remodeling. We discovered that the 5-Hz stimulation session induced a similar amount of fatigue and a five- to sixfold increase (P < 0.05) in key metabolic transcription factors, including PGC-1α, NR4A3, and ABRA as the 20-Hz session. Neither session showed a robust regulation of genes for glycolysis, oxidative phosphorylation, or mitochondria remodeling. We conclude that a low-force and low-frequency stimulation session is effective at inducing fatigue and regulating key metabolic transcription factors in human paralyzed muscle. This strategy may be an acceptable intervention to improve systemic metabolism in people with chronic paralysis. PMID:25635001

  19. Suppression of collagen Q expression in the extrajunctional regions of rat fast muscles is encoded in their stem cells (satellite cells).

    PubMed

    Glišović, Špela; Pregelj, Peter; Dolenc, Igor; Sketelj, Janez

    2013-03-25

    In rat fast muscles, collagen Q (ColQ) expression is restricted to the neuromuscular junctions. In contrast, it is high also extrajunctionally in the slow soleus muscles. Fast muscles activated by chronic low-frequency electrical stimulation, similar to neural activation of the soleus muscles, did not increase their extrajunctional expression of ColQ. We assumed that the myogenic stem cells (satellite cells) in fast and slow muscles were intrinsically different in regard to the capacity that they convey to their respective muscle fibers to increase the extrajunctional ColQ expression upon innervation. ColQ mRNA levels were determined by quantitative real-time PCR. Extensive neural suppression of the extrajunctional ColQ expression in regenerating fast muscles during maturation is a very slow process requiring 30-60 days. If the immature regenerating fast EDL muscles were indirectly or directly electrically stimulated immediately after innervation by chronic low-frequency impulse pattern for 8 days, no significant increase of the extrajunctional ColQ mRNA levels was observed in stimulated regenerates in comparison to non-stimulated ones. In contrast, the extrajunctional ColQ mRNA levels in the regenerates of the soleus muscles, trans-innervated by the EDL nerve at the time of muscle injury, increased 4- to 5-fold after 8 days of the same chronic low-frequency electrical stimulation in comparison to those in the stimulated EDL regenerates. Since both fast and slow muscles completely regenerated only from their own myogenic stem cells and were innervated by the same nerve and later activated by the same tonic pattern of impulses, these results demonstrated that the mechanism causing incapacity of regenerating fast muscles to increase their extrajunctional ColQ expression upon tonic activation is encoded in their satellite cells, which in this respect differ from those in the slow muscles.

  20. Effects of vibratory stimulations on maximal voluntary isometric contraction from delayed onset muscle soreness.

    PubMed

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong; Cho, Byung-Jun; Kim, Jin-Woo; Bo, Kak Hwang

    2013-09-01

    [Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm(2;) frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS.

  1. Effects of Vibratory Stimulations on Maximal Voluntary Isometric Contraction from Delayed Onset Muscle Soreness

    PubMed Central

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong; Cho, Byung-Jun; Kim, Jin-Woo; Bo, Kak Hwang

    2013-01-01

    [Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm2; frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS. PMID:24259922

  2. Longitudinal growth of skeletal myotubes in vitro in a new horizontal mechanical cell stimulator

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.; Karlisch, Patricia

    1989-01-01

    A tissue-culture model system for growing skeletal-muscle cells under more dynamic conditions than found in normal tissue-culture environments is described. A computerized device presented allows mechanical stimulation of the cell's substratum by 300 to 400 pct in length in the horizontal plane. Cell growth rates and skeletal-muscle organogenesis are stimulated in this in vitro system. It is noted that longitudinal myotube growth observed is accompanied by increased rates of cell proliferation and myoblast fusion. Prestretching the collagen-coated substratum before cell plating is shown to lead to increased cell proliferation, myotube orientation, and longitudinal myotube growth. The effects of substratum stretching on myogenesis in the model system are also assessed and attributed to alterations in the cell's extracellular matrix.

  3. Transplantation stimulates interstitial cell migration in hydra

    SciTech Connect

    Fujisawa, T.; David, C.N.; Bosch, T.C. )

    1990-04-01

    Migration of interstitial cells and nerve cell precursors was analyzed in Hydra magnipapillata and Hydra vulgaris (formerly Hydra attenuata). Axial grafts were made between ({sup 3}H)thymidine-labeled donor and unlabeled host tissue. Migration of labeled cells into the unlabeled half was followed for 4 days. The results indicate that the rate of migration was initially high and then slowed on Days 2-4. Regrafting fresh donor tissue on Days 2-4 maintained high levels of migration. Thus, migration appears to be stimulated by the grafting procedure itself.

  4. Lysophosphatidic acid mediates pleiotropic responses in skeletal muscle cells

    SciTech Connect

    Jean-Baptiste, Gael; Yang Zhao; Khoury, Chamel; Greenwood, Michael T.; E-mail: michael.greenwood@mcgill.ca

    2005-10-07

    Lysophosphatidic acid (LPA) is a potent modulator of growth, cell survival, and apoptosis. Although all four LPA receptors are expressed in skeletal muscle, very little is known regarding the role they play in this tissue. We used RT-PCR to demonstrate that cultured skeletal muscle C2C12 cells endogenously express multiple LPA receptor subtypes. The demonstration that LPA mediates the activation of ERK1/2 MAP kinase and Akt/PKB in C2C12 cells is consistent with the widely observed mitogenic properties of LPA. In spite of these observations, LPA did not induce proliferation in C2C12 cells. Paradoxically, we found that prolonged treatment of C2C12 cells with LPA led to caspase 3 and PARP cleavage as well as the activation of stress-associated MAP kinases JNK and p38. In spite of these typically pro-apoptotic responses, LPA did not induce cell death. Blocking ERK1/2 and Akt/PKB activation with specific pharmacological inhibitors, nevertheless, stimulated LPA-mediated apoptosis. Taken together, these results suggest that both mitogenic and apoptotic responses serve to counterbalance the effects of LPA in cultured C2C12 cells.

  5. Task dependence of responses in first dorsal interosseous muscle to magnetic brain stimulation in man.

    PubMed

    Flament, D; Goldsmith, P; Buckley, C J; Lemon, R N

    1993-05-01

    1. The response of the first dorsal interosseous (1DI) muscle to non-invasive magnetic and scalp electrical stimulation of the brain have been investigated during performance of different manual tasks. 2. The six tasks tested required activation of the 1DI muscle, either in isolation (during abduction of the index finger) or as part of a more complex pattern of muscle synergies (e.g. during power grip). The level of 1DI EMG activity across tasks was kept constant by providing subjects with visual feedback of their muscle activity. 3. In every subject (n = 14) magnetic stimulation produced larger responses during performance of complex tasks than during the simple index abduction task. The pooled results from all subjects showed that four of the five complex tasks were associated with significantly larger 1DI responses (paired t test, P < 0.05). 4. These results were confirmed at the single motor unit level for nine motor units recorded from six subjects. Subjects were requested to produce a steady discharge of the same motor unit during performance of different tasks. The probability of motor unit discharge in response to magnetic stimulation was significantly greater during complex tasks (rotation or pincer grips) than during abduction. 5. Scalp electrical stimulation was performed in three subjects with the cathode at the vertex and the anode over the contralateral motor cortex. The pattern of response amplitudes in the different tasks tended to parallel that obtained for magnetic stimulation, but the task-related differences were smaller. 6. These results suggest that during performance of the different tasks, the corticospinal volleys evoked by magnetic stimulation may vary in amplitude. The task-related cortical mechanisms that may contribute to this variability are discussed.

  6. Calpeptin Attenuated Apoptosis and Intracellular Inflammatory Changes in Muscle Cells

    PubMed Central

    Nozaki, Kenkichi; Das, Arabinda; Ray, Swapan K.; Banik, Naren L.

    2011-01-01

    In idiopathic inflammatory myopathies (IIMs), extracellular inflammatory stimulation is considered to induce secondary intracellular inflammatory changes including expression of major histocompatibility complex class-I (MHC-I) and to produce self-sustaining loop of inflammation. We hypothesize that activation of calpain, a Ca2+-sensitive protease, bridges between these extracellular inflammatory stress and intracellular secondary inflammatory changes in muscle cells. In this study, we demonstrated that treatment of rat L6 myoblast cells with interferon-gamma (IFN-γ) caused expression of MHC-I and inflammation related transcription factors (phosphorylated-extracellular signal-regulated kinase 1/2 and nuclear factor-kappa B). We also demonstrated that treatment with tumor necrosis factor-alpha (TNF-α) induced apoptotic changes and activation of calpain and cyclooxygenase-2. Further, we found that post-treatment with calpeptin attenuated the intracellular changes induced by IFN-γ or TNF-α. Our results indicate that calpain inhibition attenuates apoptosis and secondary inflammatory changes induced by extracellular inflammatory stimulation in the muscle cells. These results suggest calpain as a potential therapeutic target for treatment of IIMs. PMID:21290412

  7. Biophysical Induction of Vascular Smooth Muscle Cell Podosomes

    PubMed Central

    Kim, Na Young; Kohn, Julie C.; Huynh, John; Carey, Shawn P.; Mason, Brooke N.; Vouyouka, Ageliki G.; Reinhart-King, Cynthia A.

    2015-01-01

    Vascular smooth muscle cell (VSMC) migration and matrix degradation occurs with intimal hyperplasia associated with atherosclerosis, vascular injury, and restenosis. One proposed mechanism by which VSMCs degrade matrix is through the use of podosomes, transient actin-based structures that are thought to play a role in extracellular matrix degradation by creating localized sites of matrix metalloproteinase (MMP) secretion. To date, podosomes in VSMCs have largely been studied by stimulating cells with phorbol esters, such as phorbol 12,13-dibutyrate (PDBu), however little is known about the physiological cues that drive podosome formation. We present the first evidence that physiological, physical stimuli mimicking cues present within the microenvironment of diseased arteries can induce podosome formation in VSMCs. Both microtopographical cues and imposed pressure mimicking stage II hypertension induce podosome formation in A7R5 rat aortic smooth muscle cells. Moreover, wounding using a scratch assay induces podosomes at the leading edge of VSMCs. Notably the effect of each of these biophysical stimuli on podosome stimulation can be inhibited using a Src inhibitor. Together, these data indicate that physical cues can induce podosome formation in VSMCs. PMID:25785437

  8. Causes of excitation-induced muscle cell damage in isometric contractions: mechanical stress or calcium overload?

    PubMed

    Fredsted, Anne; Gissel, Hanne; Madsen, Klavs; Clausen, Torben

    2007-06-01

    Prolonged or unaccustomed exercise leads to muscle cell membrane damage, detectable as release of the intracellular enzyme lactic acid dehydrogenase (LDH). This is correlated to excitation-induced influx of Ca2+, but it cannot be excluded that mechanical stress contributes to the damage. We here explore this question using N-benzyl-p-toluene sulfonamide (BTS), which specifically blocks muscle contraction. Extensor digitorum longus muscles were prepared from 4-wk-old rats and mounted on holders for isometric contractions. Muscles were stimulated intermittently at 40 Hz for 15-60 min or exposed to the Ca2+ ionophore A23187. Electrical stimulation increased 45Ca influx 3-5 fold. This was followed by a progressive release of LDH, which was correlated to the influx of Ca2+. BTS (50 microM) caused a 90% inhibition of contractile force but had no effect on the excitation-induced 45Ca influx. After stimulation, ATP and creatine phosphate levels were higher in BTS-treated muscles, most likely due to the cessation of ATP-utilization for cross-bridge cycling, indicating a better energy status of these muscles. No release of LDH was observed in BTS-treated muscles. However, when exposed to anoxia, electrical stimulation caused a marked increase in LDH release that was not suppressed by BTS but associated with a decrease in the content of ATP. Dynamic passive stretching caused no increase in muscle Ca2+ content and only a minor release of LDH, whereas treatment with A23187 markedly increased LDH release both in control and BTS-treated muscles. In conclusion, after isometric contractions, muscle cell membrane damage depends on Ca2+ influx and energy status and not on mechanical stress.

  9. Mitogenic effects of vasoactive neuropeptides on cultured smooth muscle cell lines

    SciTech Connect

    Mitsuhashi, M.; Payan, D.G.

    1987-03-02

    In order to investigate the relationship between the biochemical pathways that characterize contraction and cell growth, the authors have studied both contraction, mitogenesis and protein synthesis induced by the vasoactive neuropeptides, substance P (SP), calcitonin gene related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) on four different established vascular and non-vascular smooth muscle cell lines. Contraction in vitro was evaluated by light microscopy and recorded photographically. Mitogenesis and protein synthesis were evaluated by (/sup 3/H)-thymidine incorporation into cells and (/sup 3/H)-amino acid incorporation into trichloroacetic acid precipitated materials, respectively. SP stimulated mitogenesis of A7r5 cells (embryonic rat aorta), but failed to induce significant contraction of these cells, whereas, SP induced contraction of cultured adult rat vascular smooth muscle cells (VSMC), but failed to stimulate mitogenesis. CGRP and VIP stimulated mitogenesis and protein synthesis, respectively, of DDT/sub 1/MF-2 cells (hamster vas deferens), but neither induced contraction of this cell line. All three neuropeptides showed no effect on BC/sub 3/H1 (mouse smooth muscle-like) cells. These results suggest that neuropeptides with vasoactive properties modulate different stages of cellular mitogenic responses which may be regulated by the degree of maturation of smooth muscle cell. 22 references, 5 figures.

  10. Myogenic capacity of muscle progenitor cells from head and limb muscles.

    PubMed

    Grefte, Sander; Kuijpers, Mette A R; Kuijpers-Jagtman, Anne M; Torensma, Ruurd; Von den Hoff, Johannes W

    2012-02-01

    The restoration of muscles in the soft palate of patients with cleft lip and/or palate is accompanied by fibrosis, which leads to speech and feeding problems. Treatment strategies that improve muscle regeneration have only been tested in limb muscles. Therefore, in the present study the myogenic potential of muscle progenitor cells (MPCs) isolated from head muscles was compared with that of limb muscles. Muscle progenitor cells were isolated from the head muscles and limb muscles of rats and cultured. The proliferation of MPCs was analysed by DNA quantification. The differentiation capacity was analysed by quantifying the numbers of fused cells, and by measuring the mRNA levels of differentiation markers. Muscle progenitor cells were stained to quantify the expression of paired box protein Pax 7 (Pax-7), myoblast determination protein 1 (MyoD), and myogenin. Proliferation was similar in the head MPCs and the limb MPCs. Differentiating head and limb MPCs showed a comparable number of fused cells and mRNA expression levels of myosin-1 (Myh1), myosin-3 (Myh3), and myosin-4 (Myh4). During proliferation and differentiation, the number of Pax-7(+), MyoD(+), and myogenin(+) cells in head and limb MPCs was equal. It was concluded that head and limb MPCs show similar myogenic capacities in vitro. Therefore, in vivo myogenic differences between those muscles might rely on the local microenvironment. Thus, regenerative strategies for limb muscles might also be used for head muscles.

  11. Sympathetic Responses to Noxious Stimulation of Muscle and Skin

    PubMed Central

    Burton, Alexander R.; Fazalbhoy, Azharuddin; Macefield, Vaughan G.

    2016-01-01

    Acute pain triggers adaptive physiological responses that serve as protective mechanisms that prevent continuing damage to tissues and cause the individual to react to remove or escape the painful stimulus. However, an extension of the pain response beyond signaling tissue damage and healing, such as in chronic pain states, serves no particular biological function; it is maladaptive. The increasing number of chronic pain sufferers is concerning, and the associated disease burden is putting healthcare systems around the world under significant pressure. The incapacitating effects of long-lasting pain are not just psychological – reflexes driven by nociceptors during the establishment of chronic pain may cause serious physiological consequences on regulation of other body systems. The sympathetic nervous system is inherently involved in a host of physiological responses evoked by noxious stimulation. Experimental animal and human models demonstrate a diverse array of heterogeneous reactions to nociception. The purpose of this review is to understand how pain affects the sympathetic nervous system by investigating the reflex cardiovascular and neural responses to acute pain and the long-lasting physiological responses to prolonged (tonic) pain. By observing the sympathetic responses to long-lasting pain, we can begin to understand the physiological consequences of long-term pain on cardiovascular regulation. PMID:27445972

  12. Effects of a combined mechanical stimulation protocol: Value for skeletal muscle tissue engineering.

    PubMed

    Boonen, Kristel J M; Langelaan, Marloes L P; Polak, Roderick B; van der Schaft, Daisy W J; Baaijens, Frank P T; Post, Mark J

    2010-05-28

    Skeletal muscle is an appealing topic for tissue engineering because of its variety in applications for regenerative medicine, in vitro physiological model systems, and in vitro meat production. Besides conventional biochemical cues to promote muscle tissue maturation in vitro, biophysical stimuli are necessary to reach the desired functionality and texture of the engineered tissue. Stretch, caused by active movements of the body, is an important factor present in the niche of muscle progenitor cells in vivo. We therefore investigated the effects of uniaxial ramp stretch (2%) followed by uniaxial intermittent dynamic stretch (4%) on C2C12 and murine muscle progenitor cells in a 2D and 3D environment and found that stretch negatively influenced maturation in all cases, demonstrated by decreased expression of MRFs and sarcomere proteins at the RNA level and a delay in the formation of cross striations. We therefore conclude that the current protocol is not recommended for skeletal muscle tissue engineering purposes.

  13. Bone marrow mesenchymal cells improve muscle function in a skeletal muscle re-injury model.

    PubMed

    Andrade, Bruno M; Baldanza, Marcelo R; Ribeiro, Karla C; Porto, Anderson; Peçanha, Ramon; Fortes, Fabio S A; Zapata-Sudo, Gisele; Campos-de-Carvalho, Antonio C; Goldenberg, Regina C S; Werneck-de-Castro, João Pedro

    2015-01-01

    Skeletal muscle injury is the most common problem in orthopedic and sports medicine, and severe injury leads to fibrosis and muscle dysfunction. Conventional treatment for successive muscle injury is currently controversial, although new therapies, like cell therapy, seem to be promise. We developed a model of successive injuries in rat to evaluate the therapeutic potential of bone marrow mesenchymal cells (BMMC) injected directly into the injured muscle. Functional and histological assays were performed 14 and 28 days after the injury protocol by isometric tension recording and picrosirius/Hematoxilin & Eosin staining, respectively. We also evaluated the presence and the fate of BMMC on treated muscles; and muscle fiber regeneration. BMMC treatment increased maximal skeletal muscle contraction 14 and 28 days after muscle injury compared to non-treated group (4.5 ± 1.7 vs 2.5 ± 0.98 N/cm2, p<0.05 and 8.4 ± 2.3 vs. 5.7 ± 1.3 N/cm2, p<0.05 respectively). Furthermore, BMMC treatment increased muscle fiber cross-sectional area and the presence of mature muscle fiber 28 days after muscle injury. However, there was no difference in collagen deposition between groups. Immunoassays for cytoskeleton markers of skeletal and smooth muscle cells revealed an apparent integration of the BMMC within the muscle. These data suggest that BMMC transplantation accelerates and improves muscle function recovery in our extensive muscle re-injury model.

  14. Bone Marrow Mesenchymal Cells Improve Muscle Function in a Skeletal Muscle Re-Injury Model

    PubMed Central

    Ribeiro, Karla C.; Porto, Anderson; Peçanha, Ramon; Fortes, Fabio S. A.; Zapata-Sudo, Gisele; Campos-de-Carvalho, Antonio C.; Goldenberg, Regina C. S.; Werneck-de-Castro, João Pedro

    2015-01-01

    Skeletal muscle injury is the most common problem in orthopedic and sports medicine, and severe injury leads to fibrosis and muscle dysfunction. Conventional treatment for successive muscle injury is currently controversial, although new therapies, like cell therapy, seem to be promise. We developed a model of successive injuries in rat to evaluate the therapeutic potential of bone marrow mesenchymal cells (BMMC) injected directly into the injured muscle. Functional and histological assays were performed 14 and 28 days after the injury protocol by isometric tension recording and picrosirius/Hematoxilin & Eosin staining, respectively. We also evaluated the presence and the fate of BMMC on treated muscles; and muscle fiber regeneration. BMMC treatment increased maximal skeletal muscle contraction 14 and 28 days after muscle injury compared to non-treated group (4.5 ± 1.7 vs 2.5 ± 0.98 N/cm2, p<0.05 and 8.4 ± 2.3 vs. 5.7 ± 1.3 N/cm2, p<0.05 respectively). Furthermore, BMMC treatment increased muscle fiber cross-sectional area and the presence of mature muscle fiber 28 days after muscle injury. However, there was no difference in collagen deposition between groups. Immunoassays for cytoskeleton markers of skeletal and smooth muscle cells revealed an apparent integration of the BMMC within the muscle. These data suggest that BMMC transplantation accelerates and improves muscle function recovery in our extensive muscle re-injury model. PMID:26039243

  15. Implantable power generation system utilizing muscle contractions excited by electrical stimulation.

    PubMed

    Sahara, Genta; Hijikata, Wataru; Tomioka, Kota; Shinshi, Tadahiko

    2016-06-01

    An implantable power generation system driven by muscle contractions for supplying power to active implantable medical devices, such as pacemakers and neurostimulators, is proposed. In this system, a muscle is intentionally contracted by an electrical stimulation in accordance with the demands of the active implantable medical device for electrical power. The proposed system, which comprises a small electromagnetic induction generator, electrodes with an electrical circuit for stimulation and a transmission device to convert the linear motion of the muscle contractions into rotational motion for the magneto rotor, generates electrical energy. In an ex vivo demonstration using the gastrocnemius muscle of a toad, which was 28 mm in length and weighed 1.3 g, the electrical energy generated by the prototype exceeded the energy consumed for electrical stimulation, with the net power being 111 µW. It was demonstrated that the proposed implantable power generation system has the potential to replace implantable batteries for active implantable medical devices.

  16. Uniform sarcomere shortening behavior in isolated cardiac muscle cells

    PubMed Central

    1980-01-01

    We have observed the dynamics of sarcomere shortening and the diffracting action of single, functionally intact, unattached cardiac muscle cells enzymatically isolated from the ventricular tissue of adult rats. Sarcomere length was measured either (a) continuously by a light diffraction method or (b) by direct inspection of the cell's striated image as recorded on videotape or by cinemicroscopy (120--400 frames/s). At physiological levels of added CaCl2 (0.5--2.0 mM), many cells were quiescent (i.e., they did not beat spontaneously) and contracted in response to electrical stimulation (less than or equal to 1.0-ms pulse width). Sarcomere length in the quiescent, unstimulated cells (1.93 +/- 0.10 [SD] micrometers), at peak shortening (1.57 +/- 0.13 micrometers, n = 49), and the maximum velocity of sarcomere shortening and relengthening were comparable to previous observations in intact heart muscle preparations. The dispersion of light diffracted by the cell remained narrow, and individual striations remained distinct and laterally well registered throughout the shortening- relengthening cycle. In contrast, appreciable nonuniformity and internal buckling were seen at sarcomere lengths < 1.8 micrometers when the resting cell, embedded in gelatin, was longitudinally compressed These results indicate (a) that shortening and relengthening is characterized by uniform activation between myofibrils within the cardiac cell and (b) that physiologically significant relengthening forces in living heart muscle originate at the level of the cell rather than in extracellular connections. First-order diffracted light intensity, extremely variable during sarcomere shortening, was always greatest during midrelaxation preceding the onset of a very slow and uniform phase of sarcomere relengthening. PMID:7441197

  17. Regenerative function of immune system: Modulation of muscle stem cells.

    PubMed

    Saini, Jasdeep; McPhee, Jamie S; Al-Dabbagh, Sarah; Stewart, Claire E; Al-Shanti, Nasser

    2016-05-01

    Ageing is characterised by progressive deterioration of physiological systems and the loss of skeletal muscle mass is one of the most recognisable, leading to muscle weakness and mobility impairments. This review highlights interactions between the immune system and skeletal muscle stem cells (widely termed satellite cells or myoblasts) to influence satellite cell behaviour during muscle regeneration after injury, and outlines deficits associated with ageing. Resident neutrophils and macrophages in skeletal muscle become activated when muscle fibres are damaged via stimuli (e.g. contusions, strains, avulsions, hyperextensions, ruptures) and release high concentrations of cytokines, chemokines and growth factors into the microenvironment. These localised responses serve to attract additional immune cells which can reach in excess of 1×10(5) immune cell/mm(3) of skeletal muscle in order to orchestrate the repair process. T-cells have a delayed response, reaching peak activation roughly 4 days after the initial damage. The cytokines and growth factors released by activated T-cells play a key role in muscle satellite cell proliferation and migration, although the precise mechanisms of these interactions remain unclear. T-cells in older people display limited ability to activate satellite cell proliferation and migration which is likely to contribute to insufficient muscle repair and, consequently, muscle wasting and weakness. If the factors released by T-cells to activate satellite cells can be identified, it may be possible to develop therapeutic agents to enhance muscle regeneration and reduce the impact of muscle wasting during ageing and disease.

  18. Robust conversion of marrow cells to skeletal muscle with formation of marrow-derived muscle cell colonies: A multifactorial process

    SciTech Connect

    Abedi, Mehrdad; Greer, Deborah A.; Colvin, Gerald A.; Demers, Delia A.; Dooner, Mark S.; Harpel, Jasha A.; Weier, Heinz-Ulrich G.; Lambert, Jean-Francois; Quesenberry, Peter J.

    2004-01-10

    Murine marrow cells are capable of repopulating skeletal muscle fibers. A point of concern has been the robustness of such conversions. We have investigated the impact of type of cell delivery, muscle injury, nature of delivered cell, and stem cell mobilizations on marrow to muscle conversion. We transplanted GFP transgenic marrow into irradiated C57BL/6 mice and then injured anterior tibialis muscle by cardiotoxin. One month after injury, sections were analyzed by standard and deconvolutional microscopy for expression of muscle and hematopietic markers. Irradiation was essential to conversion although whether by injury or induction of chimerism is not clear. Cardiotoxin and to a lesser extent PBS injected muscles showed significant number of GFP+ muscle fibers while uninjected muscles showed only rare GFP+ cells. Marrow conversion to muscle was increased by two cycles of G-CSF mobilization and to a lesser extent with G-CSF and steel or GM-CSF. Transplantation of female GFP to male C57 BL/6 and GFP to Rosa26 mice showed fusion of donor cells to recipient muscle. High numbers of donor derived muscle colonies and up to12 percent GFP positive muscle cells were seen after mobilization or direct injection. These levels of donor muscle chimerism approach levels which could be clinically significant in developing strategies for the treatment of muscular dystrophies. In summary, the conversion of marrow to skeletal muscle cells is based on cell fusion and is critically dependent on injury. This conversion is also numerically significant and increases with mobilization.

  19. High spatial resolution single multiwalled carbon nanotube electrode for stimulation, recording, and whole cell voltage clamping of electrically active cells

    NASA Astrophysics Data System (ADS)

    de Asis, Edward D.; Leung, Joseph; Wood, Sally; Nguyen, Cattien V.

    2009-10-01

    We report the stimulation, recording, and voltage clamp of muscle fibers using a 30 nm diameter single multiwalled carbon nanotube electrode (sMWNT electrode) tip. Because of the lower access resistance, the sMWNT electrode conducts extracellular and intracellular stimulation more efficiently compared to glass micropipettes. The sMWNT electrode records field potentials and action potentials and performs whole cell voltage clamping of single fibers.

  20. Differences in end-point force trajectories elicited by electrical stimulation of individual human calf muscles

    PubMed Central

    Giordano, S B; Segal, R L; Abelew, T A

    2009-01-01

    The purpose of this study was to investigate the end-point force trajectories of the fibularis longus (FIB), lateral gastrocnemius (LG) and medial gastrocnemius (MG) muscles. Most information about individual muscle function has come from studies which use models based on electromyographic (EMG) recordings. In this study (N=20 subjects) we used electrical stimulation (20Hz) to elicit activity in individual muscles, recorded the end-point forces at the foot and verified the selectivity of stimulation by using magnetic resonance imaging. Unexpectedly, no significant differences were found between LG and MG force directions. Stimulation of LG and MG resulted in downward and medial or lateral forces depending on the subject. We found FIB end-point forces to be significantly different than those of LG and MG. In all subjects, stimulation of FIB resulted in downward and lateral forces. Based on our results, we suggest that there are multiple factors determining when and whether LG or MG will produce a medial or lateral force and FIB consistently plays a significant role in eversion/abduction and plantarflexion. We suggest that the inter-subject variability we found is not simply an artifact of experimental or technical error but is functionally relevant and should be addressed in future studies and models. PMID:20095454

  1. Onset of ischemic colitis following use of electrical muscle stimulation (EMS) exercise equipment.

    PubMed

    Tsujimoto, Tatsuhiro; Takano, Masato; Ishikawa, Masatoshi; Tsuruzono, Takuya; Matsumura, Yoshinobu; Kitano, Hiroyuki; Yoneda, Satoshi; Yoshiji, Hitoshi; Yamao, Junichi; Fukui, Hiroshi

    2004-08-01

    Our patient was a 71-year-old man who presented with lower abdominal pain, and bloody and white mucosal stools. He purchased by mail-order an electrical muscle stimulation (EMS) device, which he strapped onto his lower abdomen, and for 2 consecutive days he underwent muscle stimulation comprising 600 contractions at 2.40 mA and 1.20 V over a 10 minute period. He experienced the onset of lower abdominal pain immediately following muscle stimulation on the second day, and then passed stools containing blood and white mucus. The cause was thought to be electrical and mechanical stimulation of the lower abdomen by the EMS equipment, either inducing colonic or vascular spasm, or dislodging thrombi associated with atrial fibrillation or atherosclerosis. This is the first known report of ischemic colitis associated with the use of EMS exercise equipment. We report this case in the belief that this condition is likely to become more common with increasing use of such devices.

  2. Smooth muscle differentiation in scleroderma fibroblastic cells.

    PubMed Central

    Sappino, A. P.; Masouyé, I.; Saurat, J. H.; Gabbiani, G.

    1990-01-01

    Using antibodies to alpha-smooth muscle actin and desmin on paraffin-embedded formalin-fixed tissue sections, the authors demonstrate that fibroblastic cells of localized and systemic scleroderma lesions express features of smooth muscle differentiation. Eleven of eleven skin specimens of systemic sclerosis patients and two of four skin specimens of localized scleroderma displayed the presence of fibroblasts expressing alpha-smooth muscle actin, a cell population that predominated in areas of prominent collagen deposition. A similar fibroblastic phenotype was found in the esophagus, the liver, and the lung specimens obtained from four patients who died of progressive systemic sclerosis. Immunostaining for desmin, performed on adjacent tissue sections, demonstrated that a minority of these fibroblastic cells present in skin and visceral lesions contained this protein. The authors' observations indicate that scleroderma fibroblasts are phenotypically related to the stromal cells previously identified in hypertrophic scars, fibromatoses, and desmoplasia; they might provide novel criteria for the characterization of scleroderma lesions and help to identify the factors responsible for phenotypic modulations in fibroblastic cells. Images Figure 1 Figure 2 Figure 3 PMID:1698026

  3. The torque-velocity relationship in large human muscles: maximum voluntary versus electrically stimulated behaviour.

    PubMed

    Pain, Matthew T G; Young, Fraser; Kim, Jinwoo; Forrester, Stephanie E

    2013-02-22

    The in vivo maximum voluntary torque-velocity profile for large muscle groups differs from the in vitro tetanic profile with lower than expected eccentric torques. Using sub-maximal transcutaneous electrical stimulation has given torque-velocity profiles with an eccentric torque plateau ∼1.4 times the isometric value. This is closer to, but still less than, the in vitro tetanic profiles with plateaus between 1.5 and 1.9 times isometric. This study investigated the maximum voluntary and sub-maximum transcutaneous electrical stimulated torque-angle-angular velocity profiles for the knee extensors and flexors in a group of healthy males. Fifteen male subjects performed maximum voluntary and sub-maximum electrically stimulated (∼40% for extensors and ∼20% for flexors) eccentric and concentric knee extension and flexions on an isovelocity dynamometer at velocities ranging from ±50°s(-1) to ±400°s(-1). The ratio of peak eccentric to peak isometric torque (T(ecc)/T(0)) was compared between the maximum voluntary and electrically stimulated conditions for both extensors and flexors, and between muscle groups. Under maximum voluntary conditions the peak torque ratio, T(ecc)/T(0), remained close to 1 (0.9-1.2) while for the electrically stimulated conditions it was significantly higher (1.4-1.7; p<0.001) and within the range of tetanic values reported from in vitro studies. In all but one case there was no significant difference in ratios between the extensors and flexors. The results showed that even the largest muscle groups have an intrinsic T(ecc)/T(0) comparable with in vitro muscle tests, and it can be ascertained from appropriate in vivo testing.

  4. Sphingosine induces phospholipase D and mitogen activated protein kinase in vascular smooth muscle cells.

    PubMed

    Taher, M M; Abd-Elfattah, A S; Sholley, M M

    1998-12-01

    The enzymes phospholipase D and diacylglycerol kinase generate phosphatidic acid which is considered to be a mitogen. Here we report that sphingosine produced a significant amount of phosphatidic acid in vascular smooth muscle cells from the rat aorta. The diacylglycerol kinase inhibitor R59 949 partially depressed sphingosine induced phosphatidic acid formation, suggesting that activation of phospholipase C and diacylglycerol kinase can not account for the bulk of phosphatidic acid produced and that additional pathways such as phospholipase D may contribute to this. Further, we have shown that phosphatidylethanol was produced by sphingosine when vascular smooth muscle cells were stimulated in the presence of ethanol. Finally, as previously shown for other cell types, sphingosine stimulated mitogen-activated protein kinase in vascular smooth muscle cells.

  5. Hydrogen peroxide stimulates ubiquitin-conjugating activity and expression of genes for specific E2 and E3 proteins in skeletal muscle myotubes

    NASA Technical Reports Server (NTRS)

    Li, Yi-Ping; Chen, Yuling; Li, Andrew S.; Reid, Michael B.

    2003-01-01

    Reactive oxygen species (ROS) are thought to promote muscle atrophy in chronic wasting diseases, but the underlying mechanism has not been determined. Here we show that H2O2 stimulates ubiquitin conjugation to muscle proteins through transcriptional regulation of the enzymes (E2 and E3 proteins) that conjugate ubiquitin to muscle proteins. Incubation of C2C12 myotubes with 100 microM H2O2 increased the rate of 125I-labeled ubiquitin conjugation to muscle proteins in whole cell extracts. This response required at least 4-h exposure to H2O2 and persisted for at least 24 h. Preincubating myotubes with cycloheximide or actinomycin D blocked H2O2 stimulation of ubiquitin-conjugating activity, suggesting that gene transcription is required. Northern blot analyses revealed that H2O2 upregulates expression of specific E3 and E2 proteins that are thought to regulate muscle catabolism, including atrogin1/MAFbx, MuRF1, and E214k. These results suggest that ROS stimulate protein catabolism in skeletal muscle by upregulating the ubiquitin conjugation system.

  6. The effect of a physiological concentration of caffeine on the endurance of maximally and submaximally stimulated mouse soleus muscle.

    PubMed

    Tallis, Jason; James, Rob S; Cox, Val M; Duncan, Michael J

    2013-03-01

    The use of caffeine as an ergogenic aid to promote endurance has been widely studied, with human literature showing the greatest benefit during submaximal muscle activities. Recent evidence suggests that the acute treatment of skeletal muscle with physiological concentrations of caffeine (70 μM maximum) will directly potentiate force production. The aims of the present study are: firstly, to assess the effects of a physiological concentration (70 μM) of caffeine on endurance in maximally activated mouse soleus (relatively slow) muscle; and secondly, to examine whether endurance changes when muscle is activated submaximally during caffeine treatment. Maximally stimulated soleus muscle treated with 70 μM caffeine resulted in a significant (17.6 %) decrease in endurance. In contrast, at a submaximal stimulation frequency, caffeine treatment significantly prolonged endurance (by 19.2 %). Findings are activation-dependent such that, during high frequency stimulation, caffeine accelerates fatigue, whereas, during low frequency stimulation, caffeine delays fatigue.

  7. Effects of Neuromuscular Electrical Stimulation and Resistance Training on Knee Extensor/Flexor Muscles.

    PubMed

    Pantović, Milan; Popović, Boris; Madić, Dejan; Obradović, Jelena

    2015-07-01

    Neuromuscular electrical stimulation (NMES) has recently drawn a lot of attention as means for strengthening of voluntary muscle contraction both in sport and rehabilitation. NMES training increases maximal voluntary contraction (MVC) force output through neural adaptations. On the other hand, positive effects of resistance training (RT) on muscle strength are well known. The aim of this study was to investigate effects of a 5-week program of NMES compared to RT program of same duration. Sample of 15 students' of faculty of sport and physical education (age 22 ± 2) were randomized in two groups: NMES (N = 7) and RT (N = 8). NMES group performed NMES superimposed over voluntary muscle contraction, RT group performed resistance training with submaximal loads. Subjects were evaluated for knee isokinetic dynamometry on both sides (60° and 180° s). After intervention no significant difference between groups were observed in isokinetic dynamometry (p = 0.177). However, applying pair sample t test within each group revealed that peak torque increased in NMES-group (p = 0.002 for right knee extensors muscles, p = 0.003 for left, respectively, at 60° and p = 0.004 for left knee extensors muscles, at angular velocity 180°). In RT group (p = 0.033 for right knee extensors muscles, p = 0.029 for right knee flexor muscles, at angular velocity 60°). Our results indicate that NMES has equal potential if not in some way better than classical RT having in mind that overload on locomotor apparatus during NMES is minimal and force of muscle contraction is equal on both sides, for enhancement of knee muscles concentric peak torque.

  8. Muscle Satellite Cell Protein Teneurin-4 Regulates Differentiation During Muscle Regeneration.

    PubMed

    Ishii, Kana; Suzuki, Nobuharu; Mabuchi, Yo; Ito, Naoki; Kikura, Naomi; Fukada, So-Ichiro; Okano, Hideyuki; Takeda, Shin'ichi; Akazawa, Chihiro

    2015-10-01

    Satellite cells are maintained in an undifferentiated quiescent state, but during muscle regeneration they acquire an activated stage, and initiate to proliferate and differentiate as myoblasts. The transmembrane protein teneurin-4 (Ten-4) is specifically expressed in the quiescent satellite cells; however, its cellular and molecular functions remain unknown. We therefore aimed to elucidate the function of Ten-4 in muscle satellite cells. In the tibialis anterior (TA) muscle of Ten-4-deficient mice, the number and the size of myofibers, as well as the population of satellite cells, were reduced with/without induction of muscle regeneration. Furthermore, we found an accelerated activation of satellite cells in the regenerated Ten-4-deficient TA muscle. The cell culture analysis using primary satellite cells showed that Ten-4 suppressed the progression of myogenic differentiation. Together, our findings revealed that Ten-4 functions as a crucial player in maintaining the quiescence of muscle satellite cells.

  9. Satellite cell proliferation in adult skeletal muscle

    NASA Technical Reports Server (NTRS)

    Booth, Frank W. (Inventor); Thomason, Donald B. (Inventor); Morrison, Paul R. (Inventor); Stancel, George M. (Inventor)

    1995-01-01

    Novel methods of retroviral-mediated gene transfer for the in vivo corporation and stable expression of eukaryotic or prokaryotic foreign genes in tissues of living animals is described. More specifically, methods of incorporating foreign genes into mitotically active cells are disclosed. The constitutive and stable expression of E. coli .beta.-galactosidase gene under the promoter control of the Moloney murine leukemia virus long terminal repeat is employed as a particularly preferred embodiment, by way of example, establishes the model upon which the incorporation of a foreign gene into a mitotically-active living eukaryotic tissue is based. Use of the described methods in therapeutic treatments for genetic diseases, such as those muscular degenerative diseases, is also presented. In muscle tissue, the described processes result in genetically-altered satellite cells which proliferate daughter myoblasts which preferentially fuse to form a single undamaged muscle fiber replacing damaged muscle tissue in a treated animal. The retroviral vector, by way of example, includes a dystrophin gene construct for use in treating muscular dystrophy. The present invention also comprises an experimental model utilizable in the study of the physiological regulation of skeletal muscle gene expression in intact animals.

  10. Skeletal muscle beta-receptors and isoproterenol-stimulated vasodilation in canine heart failure

    SciTech Connect

    Frey, M.J.; Lanoce, V.; Molinoff, P.B.; Wilson, J.R. )

    1989-11-01

    To investigate whether heart failure alters beta-adrenergic receptors on skeletal muscle and its associated vasculature, the density of beta-adrenergic receptors, isoproterenol-stimulated adenylate cyclase activity, and coupling of the guanine nucleotide-binding regulatory protein were compared in 18 control dogs and 16 dogs with heart failure induced by 5-8 wk of ventricular pacing at 260 beats/min. Hindlimb vascular responses to isoproterenol were compared in eight controls and eight of the dogs with heart failure. In dogs with heart failure, the density of beta-receptors on skeletal muscle was reduced in both gastrocnemius (control: 50 +/- 5; heart failure: 33 +/- 8 fmol/mg of protein) and semitendinosus muscle (control: 43 +/- 9; heart failure: 27 +/- 9 fmol/mg of protein, both P less than 0.05). Receptor coupling to the ternary complex, as determined by isoproterenol competition curves with and without guanosine 5'-triphosphate (GTP), was unchanged. Isoproterenol-stimulated adenylate cyclase activity was significantly decreased in semitendinosus muscle (control: 52.4 +/- 4.6; heart failure: 36.5 +/- 9.5 pmol.mg-1.min-1; P less than 0.05) and tended to be decreased in gastrocnemius muscle (control: 40.1 +/- 8.5; heart failure: 33.5 +/- 4.5 pmol.mg-1.min-1; P = NS). Isoproterenol-induced hindlimb vasodilation was not significantly different in controls and in dogs with heart failure. These findings suggest that heart failure causes downregulation of skeletal muscle beta-adrenergic receptors, probably due to receptor exposure to elevated catecholamine levels, but does not reduce beta-receptor-mediated vasodilation in muscle.

  11. Contraction of gut smooth muscle cells assessed by fluorescence imaging.

    PubMed

    Tokita, Yohei; Akiho, Hirotada; Nakamura, Kazuhiko; Ihara, Eikichi; Yamamoto, Masahiro

    2015-03-01

    Here we discuss the development of a novel cell imaging system for the evaluation of smooth muscle cell (SMC) contraction. SMCs were isolated from the circular and longitudinal muscular layers of mouse small intestine by enzymatic digestion. SMCs were stimulated by test agents, thereafter fixed in acrolein. Actin in fixed SMCs was stained with phalloidin and cell length was determined by measuring diameter at the large end of phalloidin-stained strings within the cells. The contractile response was taken as the decrease in the average length of a population of stimulated-SMCs. Various mediators and chemically identified compounds of daikenchuto (DKT), pharmaceutical-grade traditional Japanese prokinetics, were examined. Verification of the integrity of SMC morphology by phalloidin and DAPI staining and semi-automatic measurement of cell length using an imaging analyzer was a reliable method by which to quantify the contractile response. Serotonin, substance P, prostaglandin E2 and histamine induced SMC contraction in concentration-dependent manner. Two components of DKT, hydroxy-α-sanshool and hydroxy-β-sanshool, induced contraction of SMCs. We established a novel cell imaging technique to evaluate SMC contractility. This method may facilitate investigation into SMC activity and its role in gastrointestinal motility, and may assist in the discovery of new prokinetic agents.

  12. Cinematographic analysis of vascular smooth muscle cell interactions with extracellular matrix.

    PubMed

    Absher, M; Baldor, L

    1991-01-01

    The interactions of vascular smooth muscle cells with growth modulators and extracellular matrix molecules may play a role in the proliferation and migration of these cells after vascular injury and during the development of atherosclerosis. Time-lapse cinematographic techniques have been used to study cell division and migration of bovine carotid artery smooth muscle cells in response to matrix molecules consisting of solubilized basement membrane (Matrigel) and type I collagen. When cells were grown adjacent to Matrigel, both migration and cell proliferation were increased and interdivision time was shortened. Cells grown in Matrigel or in type I collagen had markedly reduced migration rates but interdivision time was not altered. Further, diffusible components of the Matrigel were found to stimulate proliferation of the smooth muscle cells.

  13. Electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induces involuntary reflex contraction of the frontalis muscles.

    PubMed

    Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Ryokuya

    2013-02-01

    The levator and frontalis muscles lack interior muscle spindles, despite consisting of slow-twitch fibres that involuntarily sustain eyelid-opening and eyebrow-raising against gravity. To compensate for this anatomical defect, this study hypothetically proposes that initial voluntary contraction of the levator fast-twitch muscle fibres stretches the mechanoreceptors in Müller's muscle and evokes proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study sought to determine whether unilateral transcutaneous electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle could induce electromyographic responses in the frontalis muscles, with monitoring responses in the orbicularis oculi muscles. The study population included 27 normal subjects and 23 subjects with aponeurotic blepharoptosis, who displayed persistently raised eyebrows on primary gaze and light eyelid closure. The stimulation induced a short-latency response in the ipsilateral frontalis muscle of all subjects and long-latency responses in the bilateral frontalis muscles of normal subjects. However, it did not induce long-latency responses in the bilateral frontalis muscles of subjects with aponeurotic blepharoptosis. The orbicularis oculi muscles showed R1 and/or R2 responses. The stimulation might reach not only the proprioceptive fibres, but also other sensory fibres related to the blink or corneal reflex. The experimental system can provoke a monosynaptic short-latency response in the ipsilateral frontalis muscle, probably through the mesencephalic trigeminal proprioceptive neuron and the frontalis motor neuron, and polysynaptic long-latency responses in the bilateral frontalis muscles through an unknown pathway. The latter neural circuit appeared to be engaged by the circumstances of aponeurotic blepharoptosis.

  14. Muscle disuse atrophy is not accompanied by changes in skeletal muscle satellite cell content.

    PubMed

    Snijders, Tim; Wall, Benjamin T; Dirks, Marlou L; Senden, Joan M G; Hartgens, Fred; Dolmans, John; Losen, Mario; Verdijk, Lex B; van Loon, Luc J C

    2014-04-01

    Muscle disuse leads to a considerable loss in skeletal muscle mass and strength. However, the cellular mechanisms underlying disuse-induced muscle fibre atrophy remain to be elucidated. Therefore we assessed the effect of muscle disuse on the CSA (cross-sectional area), muscle fibre size, satellite cell content and associated myocellular signalling pathways of the quadriceps muscle. A total of 12 healthy young (24±1 years of age) men were subjected to 2 weeks of one-legged knee immobilization via a full-leg cast. Before and immediately after the immobilization period and after 6 weeks of natural rehabilitation, muscle strength [1RM (one-repetition maximum)], muscle CSA [single slice CT (computed tomography) scan] and muscle fibre type characteristics (muscle biopsies) were assessed. Protein and/or mRNA expression of key genes [i.e. MYOD (myogenic differentiation), MYOG (myogenin) and MSTN (myostatin)] in the satellite cell regulatory pathways were determined using Western blotting and RT-PCR (real-time PCR) analyses respectively. The present study found that quadriceps CSA declined following immobilization by 8±2% (P<0.05). In agreement, both type I and type II muscle fibre size decreased 7±3% and 13±4% respectively (P<0.05). No changes were observed in satellite cell content following immobilization in either type I or type II muscle fibres. Muscle MYOG mRNA expression doubled (P<0.05), whereas MSTN protein expression decreased 30±9% (P<0.05) following immobilization. Muscle mass and strength returned to the baseline values within 6 weeks of recovery without any specific rehabilitative programme. In conclusion, 2 weeks of muscle disuse leads to considerable loss in skeletal muscle mass and strength. The loss in muscle mass was attributed to both type I and type II muscle fibre atrophy, and was not accompanied by a decline in satellite cell content.

  15. The Effects of Frequency-Dependent Dynamic Muscle Stimulation on Inhibition of Trabecular Bone Loss in a Disuse Model

    PubMed Central

    Lam, Hoyan; Qin, Yi-Xian

    2008-01-01

    Clinical electrical muscle stimulation has been shown to alleviate muscle atrophy resulting from functional disuse, yet little is known about its effect on the skeleton. The objective of this study is to evaluate the potential of dynamic muscle stimulation on disused trabecular bone, and to investigate the importance of optimized stimulation frequency in the loading regimen. Fifty-six skeletally mature Sprague-Dawley rats were divided into seven groups for the 4-week experiment: baseline control, age-matched control, hindlimb suspended (HLS), and HLS with muscle stimulation at 1 Hz, 20 Hz, 50 Hz, and 100 Hz. Muscle stimulation was carried out for 10 minutes per day for 5 days per week, total of 4 weeks. The metaphyseal and epiphyseal trabecular regions of the distal femurs were analyzed with microcomputed tomography and histomorphometry methods. HLS alone for 4-week resulted in a significant amount of trabecular bone loss and structural deterioration. Muscle contraction at 1 Hz was not sufficient to inhibit trabecular bone loss and resulted in similar amount of loss to that of HLS alone. Bone quantity and structure were significantly improved by applying muscle stimulation at mid-frequency (20 Hz & 50 Hz). Dynamic stimulation at 50 Hz demonstrated the greatest preventive effect on the skeleton against functional disused alone animals (up to +147% in bone volume fraction, +38% in trabecular number and -36% in trabecular separation). Histomorphometric analysis showed that the stimulation, regardless of its frequency, did not have an effect on the bone formation indices, such as mineral apposition rate and bone formation rate. Overall, the data demonstrated the potentials of frequency-dependent dynamic muscle contraction in regulating skeletal adaptive responses under disuse conditions. Dynamic muscle stimulation, with a specific regimen, may be beneficial to future orthopedic research in developing a countermeasure for disuse osteopenia and osteoporosis. PMID

  16. Effects of neuromuscular electrical stimulation of the knee extensor muscles on muscle soreness and different serum parameters in young male athletes: preliminary data

    PubMed Central

    Zorn, Carina; Szekeres, Thomas; Keilani, Mohammad; Fialka‐Moser, Veronika; Crevenna, Richard

    2007-01-01

    Aim To evaluate the effects of neuromuscular electrical stimulation (NMES) on muscle soreness and on a variety of serum parameters during and after NMES of knee extensor muscles of young, well trained subjects over a study period of 96 h. Methods Five male cyclists were included in this clinical observation. NMES (biphasic, asymmetric impulses) was applied through surface electrodes to both knee extensor muscles of each subject for 30 min. To determine changes in serum concentration of muscle proteins, blood samples were drawn at defined measure points before and after NMES. Muscle soreness was evaluated using a visual analogue scale at all measure points. Results There was a maximum (p<0.05) for “muscle pain” during stimulation but no significant changes could be detected after the stimulation period. Serum creatine kinase showed a peak with a significant increase (p<0.05) 24 h after NMES. Serum lactate levels only increased slightly (p = 0.08) during NMES. Conclusions Although the changes of blood parameters measured in the present work correspond to those reported in the literature on eccentric strength training, no delayed onset muscle pain could be detected. Further studies should be carried out, also investigating different stimulation protocols in non‐trained healthy subjects and in patients with less muscle mass. PMID:18037643

  17. Electrical Stimulation Promotes Cardiac Differentiation of Human Induced Pluripotent Stem Cells

    PubMed Central

    Hernández, Damián; Millard, Rodney; Sivakumaran, Priyadharshini; Wong, Raymond C. B.; Crombie, Duncan E.; Hewitt, Alex W.; Liang, Helena; Hung, Sandy S. C.; Pébay, Alice; Shepherd, Robert K.; Dusting, Gregory J.; Lim, Shiang Y.

    2016-01-01

    Background. Human induced pluripotent stem cells (iPSCs) are an attractive source of cardiomyocytes for cardiac repair and regeneration. In this study, we aim to determine whether acute electrical stimulation of human iPSCs can promote their differentiation to cardiomyocytes. Methods. Human iPSCs were differentiated to cardiac cells by forming embryoid bodies (EBs) for 5 days. EBs were then subjected to brief electrical stimulation and plated down for 14 days. Results. In iPS(Foreskin)-2 cell line, brief electrical stimulation at 65 mV/mm or 200 mV/mm for 5 min significantly increased the percentage of beating EBs present by day 14 after plating. Acute electrical stimulation also significantly increased the cardiac gene expression of ACTC1, TNNT2, MYH7, and MYL7. However, the cardiogenic effect of electrical stimulation was not reproducible in another iPS cell line, CERA007c6. Beating EBs from control and electrically stimulated groups expressed various cardiac-specific transcription factors and contractile muscle markers. Beating EBs were also shown to cycle calcium and were responsive to the chronotropic agents, isoproterenol and carbamylcholine, in a concentration-dependent manner. Conclusions. Our results demonstrate that brief electrical stimulation can promote cardiac differentiation of human iPS cells. The cardiogenic effect of brief electrical stimulation is dependent on the cell line used. PMID:26788064

  18. Conditioned medium derived from umbilical cord mesenchymal stem cells regenerates atrophied muscles.

    PubMed

    Kim, Mi Jin; Kim, Z-Hun; Kim, Sun-Mi; Choi, Yong-Soo

    2016-10-01

    We investigated the regenerative effects and regulatory mechanisms of human umbilical cord mesenchymal stem cells (UC-MSCs)-derived conditioned medium (CM) in atrophied muscles using an in vivo model. To determine the appropriate harvest point of UC-CM, active factor content was analyzed in the secretome over time. A muscle atrophy model was induced in rats by hindlimb suspension (HS) for 2 weeks. Next, UC-CM was injected directly into the soleus muscle of both hind legs to assess its regenerative efficacy on atrophy-related factors after 1 week of HS. During HS, muscle mass and muscle fiber size were significantly reduced by over 2-fold relative to untreated controls. Lactate accumulation within the muscles was similarly increased. By contrast, all of the above analytical factors were significantly improved in HS-induced rats by UC-CM injection compared with saline injection. Furthermore, the expression levels of desmin and skeletal muscle actin were significantly elevated by UC-CM treatment. Importantly, UC-CM effectively suppressed expression of the atrophy-related ubiquitin E3-ligases, muscle ring finger 1 and muscle atrophy F-box by 2.3- and 2.1-fold, respectively. UC-CM exerted its actions by stimulating the phosphoinositol-3-kinase (PI3K)/Akt signaling cascade. These findings suggest that UC-CM provides an effective stimulus to recover muscle status and function in atrophied muscles.

  19. Muscle side population cells from dystrophic or injured muscle adopt a fibro-adipogenic fate.

    PubMed

    Penton, Christopher M; Thomas-Ahner, Jennifer M; Johnson, Eric K; McAllister, Cynthia; Montanaro, Federica

    2013-01-01

    Muscle side population (SP) cells are rare multipotent stem cells that can participate in myogenesis and muscle regeneration upon transplantation. While they have been primarily studied for the development of cell-based therapies for Duchenne muscular dystrophy, little is known regarding their non-muscle lineage choices or whether the dystrophic muscle environment affects their ability to repair muscle. Unfortunately, the study of muscle SP cells has been challenged by their low abundance and the absence of specific SP cell markers. To address these issues, we developed culture conditions for the propagation and spontaneous multi-lineage differentiation of muscle SP cells. Using this approach, we show that SP cells from wild type muscle robustly differentiate into satellite cells and form myotubes without requiring co-culture with myogenic cells. Furthermore, this myogenic activity is associated with SP cells negative for immune (CD45) and vascular (CD31) markers but positive for Pax7, Sca1, and the mesenchymal progenitor marker PDGFRα. Additionally, our studies revealed that SP cells isolated from dystrophic or cardiotoxin-injured muscle fail to undergo myogenesis. Instead, these SP cells rapidly expand giving rise to fibroblast and adipocyte progenitors (FAPs) and to their differentiated progeny, fibroblasts and adipocytes. Our findings indicate that muscle damage affects the lineage choices of muscle SP cells, promoting their differentiation along fibro-adipogenic lineages while inhibiting myogenesis. These results have implications for a possible role of muscle SP cells in fibrosis and fat deposition in muscular dystrophy. In addition, our studies provide a useful in vitro system to analyze SP cell biology in both normal and pathological conditions.

  20. Stem Cell Stimulation of Endogenous Myocyte Regeneration

    PubMed Central

    Weil, Brian R.; Canty, John M.

    2015-01-01

    Cell-based therapy has emerged as a promising approach to combat the myocyte loss and cardiac remodeling that characterize the progression of left ventricular dysfunction to heart failure. Several clinical trials conducted during the past decade have shown that a variety of autologous bone marrow- and peripheral blood-derived stem and progenitor cell populations can be safely administered to patients with ischemic heart disease and yield modest improvements in cardiac function. Concurrently, rapid progress has been made at the preclinical level to identify novel therapeutic cell populations, delineate the mechanisms underlying cell-mediated cardiac repair, and optimize cell-based approaches for clinical use. The following review summarizes the progress that has been made in this rapidly evolving field over the past decade and examines how our current understanding of the mechanisms involved in successful cardiac regeneration should direct future investigation in this area. Particular emphasis is placed on discussion of the general hypothesis that the benefits of cell therapy primarily result from stimulation of endogenous cardiac repair processes that have only recently been identified in the adult mammalian heart, rather than direct differentiation of exogenous cells. Continued scientific investigation in this area will guide the optimization of cell-based approaches for myocardial regeneration, with the ultimate goal of clinical implementation and substantial improvement in our ability to restore cardiac function in ischemic heart disease patients. PMID:23577634

  1. Stem cell stimulation of endogenous myocyte regeneration.

    PubMed

    Weil, Brian R; Canty, John M

    2013-08-01

    Cell-based therapy has emerged as a promising approach to combat the myocyte loss and cardiac remodelling that characterize the progression of left ventricular dysfunction to heart failure. Several clinical trials conducted over the past decade have shown that a variety of autologous bone-marrow- and peripheral-blood-derived stem and progenitor cell populations can be safely administered to patients with ischaemic heart disease and yield modest improvements in cardiac function. Concurrently, rapid progress has been made at the pre-clinical level to identify novel therapeutic cell populations, delineate the mechanisms underlying cell-mediated cardiac repair and optimize cell-based approaches for clinical use. The following review summarizes the progress that has been made in this rapidly evolving field over the past decade and examines how our current understanding of the mechanisms involved in successful cardiac regeneration should direct future investigation in this area. Particular emphasis is placed on discussion of the general hypothesis that the benefits of cell therapy primarily result from stimulation of endogenous cardiac repair processes that have only recently been identified in the adult mammalian heart, rather than direct differentiation of exogenous cells. Continued scientific investigation in this area will guide the optimization of cell-based approaches for myocardial regeneration, with the ultimate goal of clinical implementation and substantial improvement in our ability to restore cardiac function in ischaemic heart disease patients.

  2. Upper-limb muscle responses to epidural, subdural and intraspinal stimulation of the cervical spinal cord

    NASA Astrophysics Data System (ADS)

    Sharpe, Abigail N.; Jackson, Andrew

    2014-02-01

    Objective. Electrical stimulation of the spinal cord has potential applications following spinal cord injury for reanimating paralysed limbs and promoting neuroplastic changes that may facilitate motor rehabilitation. Here we systematically compare the efficacy, selectivity and frequency-dependence of different stimulation methods in the cervical enlargement of anaesthetized monkeys. Approach. Stimulating electrodes were positioned at multiple epidural and subdural sites on both dorsal and ventral surfaces, as well as at different depths within the spinal cord. Motor responses were recorded from arm, forearm and hand muscles. Main results. Stimulation efficacy increased from dorsal to ventral stimulation sites, with the exception of ventral epidural electrodes which had the highest recruitment thresholds. Compared to epidural and intraspinal methods, responses to subdural stimulation were more selective but also more similar between adjacent sites. Trains of stimuli delivered to ventral sites elicited consistent responses at all frequencies whereas from dorsal sites we observed a mixture of short-latency facilitation and long-latency suppression. Finally, paired stimuli delivered to dorsal surface and intraspinal sites exhibited symmetric facilitatory interactions at interstimulus intervals between 2-5 ms whereas on the ventral side interactions tended to be suppressive for near-simultaneous stimuli. Significance. We interpret these results in the context of differential activation of afferent and efferent roots and intraspinal circuit elements. In particular, we propose that distinct direct and indirect actions of spinal cord stimulation on motoneurons may be advantageous for different applications, and this should be taken into consideration when designing neuroprostheses for upper-limb function.

  3. Regulation of the muscle fiber microenvironment by activated satellite cells during hypertrophy.

    PubMed

    Fry, Christopher S; Lee, Jonah D; Jackson, Janna R; Kirby, Tyler J; Stasko, Shawn A; Liu, Honglu; Dupont-Versteegden, Esther E; McCarthy, John J; Peterson, Charlotte A

    2014-04-01

    Our aim in the current study was to determine the necessity of satellite cells for long-term muscle growth and maintenance. We utilized a transgenic Pax7-DTA mouse model, allowing for the conditional depletion of > 90% of satellite cells with tamoxifen treatment. Synergist ablation surgery, where removal of synergist muscles places functional overload on the plantaris, was used to stimulate robust hypertrophy. Following 8 wk of overload, satellite cell-depleted muscle demonstrated an accumulation of extracellular matrix (ECM) and fibroblast expansion that resulted in reduced specific force of the plantaris. Although the early growth response was normal, an attenuation of hypertrophy measured by both muscle wet weight and fiber cross-sectional area occurred in satellite cell-depleted muscle. Isolated primary myogenic progenitor cells (MPCs) negatively regulated fibroblast ECM mRNA expression in vitro, suggesting a novel role for activated satellite cells/MPCs in muscle adaptation. These results provide evidence that satellite cells regulate the muscle environment during growth.

  4. Electrical Stimulation of the Suprahyoid Muscles in Brain-injured Patients with Dysphagia: A Pilot Study

    PubMed Central

    Beom, Jaewon; Kim, Sang Jun

    2011-01-01

    Objective To investigate the therapeutic effects of repetitive electrical stimulation of the suprahyoid muscles in brain-injured patients with dysphagia. Method Twenty-eight brain-injured patients who showed reduced laryngeal elevation and supraglottic penetration or subglottic aspiration during a videofluoroscopic swallowing study (VFSS) were selected. The patients received either conventional dysphagia management (CDM) or CDM with repetitive electrical stimulation of the suprahyoid muscles (ESSM) for 4 weeks. The videofluoroscopic dysphagia scale (VDS) using the VFSS and American Speech-Language-Hearing Association National Outcome Measurement System (ASHA NOMS) swallowing scale (ASHA level) was used to determine swallowing function before and after treatment. Results VDS scores decreased from 29.8 to 17.9 in the ESSM group, and from 29.2 to 16.6 in the CDM group. However, there was no significant difference between the groups (p=0.796). Six patients (85.7%) in the ESSM group and 14 patients (66.7%) in the CDM group showed improvement according to the ASHA level with no significant difference between the ESSM and CDM groups (p=0.633). Conclusion Although repetitive neuromuscular electrical stimulation of the suprahyoid muscles did not further improve the swallowing function of dysphagia patients with reduced laryngeal elevation, more patients in the ESSM group showed improvement in the ASHA level than those in the CDM group. Further studies with concurrent controls and a larger sample group are required to fully establish the effects of repetitive neuromuscular electrical stimulation of the suprahyoid muscles in dysphagia patients. PMID:22506140

  5. Evaluation of microcurrent electrical nerve stimulation (MENS) effectiveness on muscle pain in temporomandibular disorders patients.

    PubMed

    Zuim, Paulo Renato Junqueira; Garcia, Alicio Rosalino; Turcio, Karina Helga Leal; Hamata, Marcelo Matida

    2006-01-01

    The effect of Microcurrent Electrical Nerve Stimulation (MENS) was evaluated and compared with occlusal splint therapy in temporomandibular disorders (TMD) patients with muscle pain. Twenty TMD patients were divided into four groups. One received occlusal splint therapy and MENS (I); other received splints and placebo MENS (II); the third, only MENS (III) and the last group, placebo MENS (IV). Sensitivity derived from muscle palpation was evaluated using a visual analogue scale. Results were submitted to analysis of variance (p<0.05). There was reduction of pain level in all groups: group I (occlusal splint and MENS) had a 47.7% reduction rate; group II (occlusal splint and placebo MENS), 66.7%; group III (MENS), 49.7% and group IV (placebo MENS), 16.5%. In spite of that, there was no statistical difference (analysis of variance / p<0.05) between MENS and occlusal splint therapy regarding muscle pain reduction in TMD patients after four weeks.

  6. Dietary stimulators of GLUT4 expression and translocation in skeletal muscle: a mini-review.

    PubMed

    Gannon, Nicholas P; Conn, Carole A; Vaughan, Roger A

    2015-01-01

    Chronic insulin resistance can lead to type II diabetes mellitus, which is also directly influenced by an individual's genetics as well as their lifestyle. Under normal circumstances, insulin facilitates glucose uptake in skeletal muscle and adipose tissue by stimulating glucose transporter 4 (GLUT4) translocation and activity. GLUT4 activity is directly correlated with the ability to clear elevated blood glucose and insulin sensitivity. In diabetes, energy excess and prolonged hyperinsulinemia suppress muscle and adipose response to insulin, in part through reduced GLUT4 membrane levels. This work uniquely describes much of the experimental data demonstrating the effects of various dietary components on GLUT4 expression and translocation in skeletal muscle. These observations implicate several individual dietary chemicals as potential adjuvant therapies in the maintenance of diabetes and insulin resistance.

  7. Measuring phospholipase D activity in insulin-secreting pancreatic beta-cells and insulin-responsive muscle cells and adipocytes.

    PubMed

    Cazzolli, Rosanna; Huang, Ping; Teng, Shuzhi; Hughes, William E

    2009-01-01

    Phospholipase D (PLD) is an enzyme producing phosphatidic acid and choline through hydrolysis of phosphatidylcholine. The enzyme has been identified as a member of a variety of signal transduction cascades and as a key regulator of numerous intracellular vesicle trafficking processes. A role for PLD in regulating glucose homeostasis is emerging as the enzyme has recently been identified in events regulating exocytosis of insulin from pancreatic beta-cells and also in insulin-stimulated glucose uptake through controlling GLUT4 vesicle exocytosis in muscle and adipose tissue. We present methodologies for assessing cellular PLD activity in secretagogue-stimulated insulin-secreting pancreatic beta-cells and also insulin-stimulated adipocyte and muscle cells, two of the principal insulin-responsive cell types controlling blood glucose levels.

  8. Isoproterenol directs hair follicle-associated pluripotent (HAP) stem cells to differentiate in vitro to cardiac muscle cells which can be induced to form beating heart-muscle tissue sheets.

    PubMed

    Yamazaki, Aiko; Yashiro, Masateru; Mii, Sumiyuki; Aki, Ryoichi; Hamada, Yuko; Arakawa, Nobuko; Kawahara, Katsumasa; Hoffman, Robert M; Amoh, Yasuyuki

    2016-01-01

    Nestin-expressing hair-follicle-associated pluripotent (HAP) stem cells are located in the bulge area of the follicle. Previous studies have shown that HAP stem cells can differentiate to neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. HAP stem cells effected nerve and spinal cord regeneration in mouse models. Recently, we demonstrated that HAP stem cells differentiated to beating cardiac muscle cells. The differentiation potential to cardiac muscle cells was greatest in the upper part of the follicle. The beat rate of the cardiac muscle cells was stimulated by isoproterenol. In the present study, we observed that isoproterenol directs HAP stem cells to differentiate to cardiac muscle cells in large numbers in culture compared to HAP stem cells not supplemented with isoproterenol. The addition of activin A, bone morphogenetic protein 4, and basic fibroblast growth factor, along with isoproternal, induced the cardiac muscle cells to form tissue sheets of beating heart muscle cells. These results demonstrate that HAP stem cells have great potential to form beating cardiac muscle cells in tissue sheets.

  9. Fractalkine (CX3CL1) stimulated by nuclear factor kappaB (NF-kappaB)-dependent inflammatory signals induces aortic smooth muscle cell proliferation through an autocrine pathway.

    PubMed

    Chandrasekar, Bysani; Mummidi, Srinivas; Perla, Rao P; Bysani, Sailaja; Dulin, Nickolai O; Liu, Feng; Melby, Peter C

    2003-07-15

    Fractalkine (also known as CX3CL1), a CX3C chemokine, activates and attracts monocytes/macrophages to the site of injury/inflammation. It binds to CX3C receptor 1 (CX3CR1), a pertussis toxin-sensitive G-protein-coupled receptor. In smooth muscle cells (SMCs), fractalkine is induced by proinflammatory cytokines [tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma)], which may mediate monocyte adhesion to SMCs. However, the mechanisms underlying its induction are unknown. In addition, it is unlear whether SMCs express CX3CR1. TNF-alpha activated nuclear factor kappaB (NF-kappaB) and induced fractalkine and CX3CR1 expression in a time-dependent manner in rat aortic SMCs. Transient transfections with dominant-negative (dn) inhibitory kappaB (IkappaB)-alpha, dnIkappaB-beta, dnIkappaB kinase (IKK)-gamma, kinase-dead (kd) NF-kappaB-inducing kinase (NIK) and kdIKK-beta, or pretreatment with wortmannin, Akt inhibitor, pyrrolidinecarbodithioc acid ammonium salt ('PDTC') or MG-132, significantly attenuated TNF-alpha-induced fractalkine and CX3CR1 expression. Furthermore, expression of dn TNF-alpha-receptor-associated factor 2 (TRAF2), but not dnTRAF6, inhibited TNF-alpha signal transduction. Pretreatment with pertussis toxin or neutralizing anti-CX3CR1 antibodies attenuated TNF-alpha-induced fractalkine expression, indicating that fractalkine autoregulation plays a role in TNF-alpha-induced sustained fractalkine expression. Fractalkine induced its own expression, via pertussis toxin-sensitive G-proteins, phosphoinositide 3-kinase (PI 3-kinase), phosphoinositide-dependent kinase 1 (PDK1), Akt, NIK, IKK and NF-kappaB activation, and induced SMC cell-cell adhesion and cellular proliferation. Taken together, our results demonstrate that TNF-alpha induces the expression of fractalkine and CX3CR1 in rat aortic SMCs and that this induction is mediated by NF-kappaB activation. We also show that fractalkine induces its own expression, which is mediated by the PI 3

  10. Secretion of Growth Hormone in Response to Muscle Sensory Nerve Stimulation

    NASA Technical Reports Server (NTRS)

    Grindeland, Richard E.; Roy, R. R.; Edgerton, V. R.; Gosselink, K. L.; Grossman, E. J.; Sawchenko, P. E.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    Growth hormone (GH) secretion is stimulated by aerobic and resistive exercise and inhibited by exposure to actual or simulated (bedrest, hindlimb suspension) microgravity. Moreover, hypothalamic growth hormone-releasing factor (GRF) and preproGRF mRNA are markedly decreased in spaceflight rats. These observations suggest that reduced sensory input from inactive muscles may contribute to the reduced secretion of GH seen in "0 G". Thus, the aim of this study was to determine the effect of muscle sensory nerve stimulation on secretion of GH. Fed male Wistar rats (304 +/- 23 g) were anesthetized (pentobarbital) and the right peroneal (Pe), tibial (T), and sural (S) nerves were cut. Electrical stimulation of the distal (D) or proximal (P) ends of the nerves was implemented for 15 min. to mimic the EMG activity patterns of ankle extensor muscles of a rat walking 1.5 mph. The rats were bled by cardiac puncture and their anterior pituitaries collected. Pituitary and plasma bioactive (BGH) and immunoactive (IGH) GH were measured by bioassay and RIA.

  11. GARNL1, a major RalGAP α subunit in skeletal muscle, regulates insulin-stimulated RalA activation and GLUT4 trafficking via interaction with 14-3-3 proteins.

    PubMed

    Chen, Qiaoli; Quan, Chao; Xie, Bingxian; Chen, Liang; Zhou, Shuilian; Toth, Rachel; Campbell, David G; Lu, Shuangshuang; Shirakawa, Ryutaro; Horiuchi, Hisanori; Li, Chaojun; Yang, Zhongzhou; MacKintosh, Carol; Wang, Hong Yu; Chen, Shuai

    2014-08-01

    Insulin and muscle contraction each stimulate translocation of the glucose transporter GLUT4 to the plasma membrane in skeletal muscle, an important process regulating whole-body glucose homeostasis. RalA mediates insulin-stimulated GLUT4 translocation; however, it is unclear how this small GTPase is regulated in skeletal muscle in response to insulin. Here, we identified GARNL1/RalGAPα1, a major α subunit of the Ral-GTPase activating protein in skeletal muscle, as a protein whose phosphorylation and binding to the regulatory 14-3-3 proteins is stimulated by insulin and also by muscle contraction. The insulin-stimulated interaction with 14-3-3 involved PKB/Akt-mediated phosphorylation of Thr(735) on GARNL1/RalGAPα1. Knockdown of GARNL1/RalGAPα1 increased, while overexpression of GARNL1/RalGAPα1(Thr735Ala) mutant protein decreased, the RalA activation and the RalA-dependent GLUT4 translocation in response to insulin in muscle cells. These findings show that GARNL1/RalGAPα1 is the missing link that connects the insulin-PKB/Akt signaling pathway with the activation of the RalA small GTPase in muscle cells. GARNL1/RalGAPα1 and its phosphorylation and/or binding to 14-3-3s are critical for GLUT4 trafficking through RalA in muscle cells.

  12. Blood flow distribution in dog gastrocnemius muscle at rest and during stimulation

    SciTech Connect

    Piiper, J.; Pendergast, D.R.; Marconi, C.; Meyer, M.; Heisler, N.; Cerretelli, P.

    1985-06-01

    The distribution of blood flow within the isolated perfused dog gastrocnemius muscle (weight 100-240 g) was studied by intra-arterial injection of radioactively labeled microspheres (diameter 15 micron) at rest and during supramaximal stimulation to rhythmic isotonic tetanic contractions of varied frequency against varied loads. After the experiment the muscle was cut into 180-250 pieces of approximately 0.75 g each, and the blood flow to each muscle piece was determined from its radioactivity. The inhomogeneity of blood flow was represented as the frequency distribution of the ratios of regional specific blood flow, i.e., blood flow per unit tissue weight of the piece, QR, to the overall specific blood flow of the muscle, Q. The QR/Q values for the individual pieces of a muscle were found to vary widely both at rest and during stimulation. With rising work load the frequency distribution had a tendency to broaden and flatten, indicating increasing perfusion inhomogeneity. On the average of the experiments, there was no significant difference in specific blood flow between the three anatomic components of the gastrocnemius (lateral and medial heads of gastrocnemius and flexor digitorum superficialis) nor between the superficial and deep portions within these anatomic components, only the distal third of the muscle was relatively less perfused compared with the proximal two-thirds. The considerable inhomogeneity of blood flow as revealed by microsphere embolization and by other methods is expected to exert important limiting effects on local O/sub 2/ supply, particularly during exercise.

  13. Na,K-ATPase α2 activity in mammalian skeletal muscle T-tubules is acutely stimulated by extracellular K+.

    PubMed

    DiFranco, Marino; Hakimjavadi, Hesamedin; Lingrel, Jerry B; Heiny, Judith A

    2015-10-01

    The Na,K-ATPase α2 isoform is the predominant Na,K-ATPase in adult skeletal muscle and the sole Na,K-ATPase in the transverse tubules (T-tubules). In quiescent muscles, the α2 isozyme operates substantially below its maximal transport capacity. Unlike the α1 isoform, the α2 isoform is not required for maintaining resting ion gradients or the resting membrane potential, canonical roles of the Na,K-ATPase in most other cells. However, α2 activity is stimulated immediately upon the start of contraction and, in working muscles, its contribution is crucial to maintaining excitation and resisting fatigue. Here, we show that α2 activity is determined in part by the K+ concentration in the T-tubules, through its K+ substrate affinity. Apparent K+ affinity was determined from measurements of the K1/2 for K+ activation of pump current in intact, voltage-clamped mouse flexor digitorum brevis muscle fibers. Pump current generated by the α2 Na,K-ATPase, Ip, was identified as the outward current activated by K+ and inhibited by micromolar ouabain. Ip was outward at all potentials studied (-90 to -30 mV) and increased with depolarization in the subthreshold range, -90 to -50 mV. The Q10 was 2.1 over the range of 22-37°C. The K1/2,K of Ip was 4.3±0.3 mM at -90 mV and was relatively voltage independent. This K+ affinity is lower than that reported for other cell types but closely matches the dynamic range of extracellular K+ concentrations in the T-tubules. During muscle contraction, T-tubule luminal K+ increases in proportion to the frequency and duration of action potential firing. This K1/2,K predicts a low fractional occupancy of K+ substrate sites at the resting extracellular K+ concentration, with occupancy increasing in proportion to the frequency of membrane excitation. The stimulation of preexisting pumps by greater K+ site occupancy thus provides a rapid mechanism for increasing α2 activity in working muscles.

  14. Effects of muscle electrical stimulation on peak VO2 in cardiac transplant patients.

    PubMed

    Vaquero, A F; Chicharro, J L; Gil, L; Ruiz, M P; Sánchez, V; Lucía, A; Urrea, S; Gómez, M A

    1998-07-01

    Peak oxygen consumption (peak VO2) has become a critical component in the evaluation of heart transplant recipients (HTR). In these patients, peak VO2 remains low after cardiac transplantation mainly because of persisting peripheral limitations in the working muscles. Muscular electrical stimulation, on the other hand, has been shown to enhance the oxidative capacity of healthy muscle. It was the purpose of our investigation to study the effects of ES on the peak VO2 of HTR. Fourteen (11 males and 3 females) HTR (age: 57+/-7yr, mean +/- SD; height: 163+/-7 cm, weight: 70.5+/-8.6 kg) were selected as subjects and each of them was randomly assigned to one of two groups: (a) group EXP (n = 7), receiving electrical stimulation on both quadriceps muscles during a period of 8 weeks, and (b) group CONT (n = 7), not receiving electrical stimulation. Before (PRE) and after (POST) the aforementioned 8-week period, respectively, all the subjects performed a cardiopulmonary exercise test (ramp protocol) on a cycle ergometer for peak VO2 determination. PRE values of peak VO2 were similar in both groups (17.1+/-2.0 vs 16.9+/-3.8ml x kg(-1) x min(-1) in EXP and CONT, respectively). However, peak values of VO2 significantly increased in EXP (p < 0.05) after the period of electrical stimulation (POST peak VO2: 18.7+/-2.0ml x kg(-1)), whereas no change was observed in CONT (POST peak VO2: 16.2+/-3.2 ml x kg(-1) x min(-1)). In conclusion, electrical stimulation could therefore be used to improve the functional capacity of HTR, and might be included in the rehabilitation programs of this population group.

  15. Hyaluronan stimulates pancreatic cancer cell motility

    PubMed Central

    Cheng, Xiao-Bo; Kohi, Shiro; Koga, Atsuhiro; Hirata, Keiji; Sato, Norihiro

    2016-01-01

    Hyaluronan (HA) accumulates in pancreatic ductal adenocarcinoma (PDAC), but functional significance of HA in the aggressive phenotype remains unknown. We used different models to investigate the effect of HA on PDAC cell motility by wound healing and transwell migration assay. Changes in cell motility were examined in 8 PDAC cell lines in response to inhibition of HA production by treatment with 4-methylumbelliferone (4-MU) and to promotion by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or by co-culture with tumor-derived stromal fibroblasts. We also investigated changes in cell motility by adding exogenous HA. Additionally, mRNA expressions of hyaluronan synthases and hyaluronidases were examined using real time RT-PCR. Inhibition of HA by 4-MU significantly decreased the migration, whereas promotion of HA by TPA or co-culture with tumor-derived fibroblasts significantly increased the migration of PDAC cells. The changes in HA production by these treatments tended to be associated with changes in HAS3 mRNA expression. Furthermore, addition of exogenous HA, especially low-molecular-weight HA, significantly increased the migration of PDAC cells. These findings suggest that HA stimulates PDAC cell migration and thus represents an ideal therapeutic target to prevent invasion and metastasis. PMID:26684359

  16. Abcg2 labels multiple cell types in skeletal muscle and participates in muscle regeneration

    PubMed Central

    Doyle, Michelle J.; Zhou, Sheng; Tanaka, Kathleen Kelly; Pisconti, Addolorata; Farina, Nicholas H.; Sorrentino, Brian P.

    2011-01-01

    Skeletal muscle contains progenitor cells (satellite cells) that maintain and repair muscle. It also contains muscle side population (SP) cells, which express Abcg2 and may participate in muscle regeneration or may represent a source of satellite cell replenishment. In Abcg2-null mice, the SP fraction is lost in skeletal muscle, although the significance of this loss was previously unknown. We show that cells expressing Abcg2 increased upon injury and that muscle regeneration was impaired in Abcg2-null mice, resulting in fewer centrally nucleated myofibers, reduced myofiber size, and fewer satellite cells. Additionally, using genetic lineage tracing, we demonstrate that the progeny of Abcg2-expressing cells contributed to multiple cell types within the muscle interstitium, primarily endothelial cells. After injury, Abcg2 progeny made a minor contribution to regenerated myofibers. Furthermore, Abcg2-labeled cells increased significantly upon injury and appeared to traffic to muscle from peripheral blood. Together, these data suggest an important role for Abcg2 in positively regulating skeletal muscle regeneration. PMID:21949413

  17. Atlas of the muscle motor points for the lower limb: implications for electrical stimulation procedures and electrode positioning.

    PubMed

    Botter, Alberto; Oprandi, Gianmosè; Lanfranco, Fabio; Allasia, Stefano; Maffiuletti, Nicola A; Minetto, Marco Alessandro

    2011-10-01

    The aim of the study was to investigate the uniformity of the muscle motor point location for lower limb muscles in healthy subjects. Fifty-three subjects of both genders (age range: 18-50 years) were recruited. The muscle motor points were identified for the following ten muscles of the lower limb (dominant side): vastus medialis, rectus femoris, and vastus lateralis of the quadriceps femoris, biceps femoris, semitendinosus, and semimembranosus of the hamstring muscles, tibialis anterior, peroneus longus, lateral and medial gastrocnemius. The muscle motor point was identified by scanning the skin surface with a stimulation pen electrode and corresponded to the location of the skin area above the muscle in which an electrical pulse evoked a muscle twitch with the least injected current. For each investigated muscle, 0.15 ms square pulses were delivered through the pen electrode at low current amplitude (<10 mA) and frequency (2 Hz). 16 motor points were identified in the 10 investigated muscles of almost all subjects: 3 motor points for the vastus lateralis, 2 motor points for rectus femoris, vastus medialis, biceps femoris, and tibialis anterior, 1 motor point for the remaining muscles. An important inter-individual variability was observed for the position of the following 4 out of 16 motor points: vastus lateralis (proximal), biceps femoris (short head), semimembranosus, and medial gastrocnemius. Possible implications for electrical stimulation procedures and electrode positioning different from those commonly applied for thigh and leg muscles are discussed.

  18. The role of muscle cells in regulating cartilage matrix production

    PubMed Central

    Cairns, Dana M.; Lee, Philip G.; Uchimura, Tomoya; Seufert, Christopher R.; Kwon, Heenam; Zeng, Li

    2009-01-01

    Muscle is one of the tissues located in close proximity to cartilage tissue. Although it has been suggested that muscle could influence skeletal development through generating mechanical forces by means of contraction, very little is known regarding whether muscle cells release biochemical signals to regulate cartilage gene expression. We tested the hypothesis that muscle cells directly regulate cartilage matrix production by analyzing chondrocytes co-cultured with muscle cells in 2D or 3D conditions. We found that chondrocytes cultured with C2C12 muscle cells exhibited enhanced alcian blue staining and elevated expression of collagen II and collagen IX proteins. While non-muscle cells do not promote cartilage matrix production, converting them into muscle cells enhanced their pro-chondrogenic activity. Furthermore, muscle cell-conditioned medium led to increased cartilage matrix production, suggesting that muscle cells secrete pro-chondrogenic factors. Taken together, our study suggests that muscle cells may play an important role in regulating cartilage gene expression. This result may ultimately lead to the discovery of novel factors that regulate cartilage formation and homeostasis, and provide insights into improving the strategies for regenerating cartilage. PMID:19813241

  19. Muscle enhancement using closed-loop electrical stimulation: volitional versus induced torque.

    PubMed

    Langzam, E; Nemirovsky, Y; Isakov, E; Mizrahi, J

    2007-06-01

    In cases of partial deficiency of muscle activation capacity, force augmentation can be achieved by hybrid activation, i.e., by combining electrical stimulation (ES) with volitional activation. In this activation modality the shares of the volitional and induced torques within the overall hybrid torque are unknown. The purpose of this study was to suggest a computational approach to parcel out the volitional and stimulation induced components of joint torque generated during combined voluntary and electrical activation of the Tibialis Anterior muscle (TA). For this purpose, isometric contraction of the TA was studied on 5 healthy subjects, using an activation protocol involving ES alone, volitional activation alone and hybrid activation. Ankle torque and TA EMG were measured. A computational algorithm was developed to dissociate the volitional from the overall torque, based on EMG filtering and on pre-measured calibration curves of volitional torque versus EMG. The results indicated that for a certain hybrid torque there is a linear decaying relationship between the induced torque and the volitional torque shares. Moreover, based on a defined enhancement ratio, the results indicate that within the range of stimulation intensities, there exist regions of increased facilitation, in which the stimulation efficiency is higher under combined compared to isolated conditions.

  20. Immortalization of primary human smooth muscle cells.

    PubMed Central

    Perez-Reyes, N; Halbert, C L; Smith, P P; Benditt, E P; McDougall, J K

    1992-01-01

    Primary human aortic and myometrial smooth muscle cells (SMCs) were immortalized using an amphotropic recombinant retroviral construct containing the E6 and E7 open reading frames (ORFs) of human papillomavirus type 16. The SMCs expressing the E6/E7 ORFs have considerably elevated growth rates when compared with nonimmortalized control cells and show no signs of senescence with long-term passage. The first SMC line derived in this study has been maintained in continuous tissue culture for greater than 1 year (greater than 180 population doublings). The immortalized SMCs have decreased cell size and decreased content of muscle-specific alpha-actin filaments as determined by indirect immunofluorescence. Southern blot analysis has demonstrated the stable integration of the E6/E7 ORFs in the retrovirally infected cells, and radioimmunoprecipitation has confirmed the continued expression of the E6 and E7 genes. Cytogenetic studies of the SMC lines have revealed essentially diploid populations except for the myometrial clonal line, which became aneuploid at late passage (greater than 125 doublings). These cell lines were not tumorigenic in nude mice. Images PMID:1311088

  1. Notch Signaling in Vascular Smooth Muscle Cells.

    PubMed

    Baeten, J T; Lilly, B

    2017-01-01

    The Notch signaling pathway is a highly conserved pathway involved in cell fate determination in embryonic development and also functions in the regulation of physiological processes in several systems. It plays an especially important role in vascular development and physiology by influencing angiogenesis, vessel patterning, arterial/venous specification, and vascular smooth muscle biology. Aberrant or dysregulated Notch signaling is the cause of or a contributing factor to many vascular disorders, including inherited vascular diseases, such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, associated with degeneration of the smooth muscle layer in cerebral arteries. Like most signaling pathways, the Notch signaling axis is influenced by complex interactions with mediators of other signaling pathways. This complexity is also compounded by different members of the Notch family having both overlapping and unique functions. Thus, it is vital to fully understand the roles and interactions of each Notch family member in order to effectively and specifically target their exact contributions to vascular disease. In this chapter, we will review the Notch signaling pathway in vascular smooth muscle cells as it relates to vascular development and human disease.

  2. The interrelation between aPKC and glucose uptake in the skeletal muscle during contraction and insulin stimulation.

    PubMed

    Santos, J M; Benite-Ribeiro, S A; Queiroz, G; Duarte, J A

    2014-12-01

    Contraction and insulin increase glucose uptake in skeletal muscle. While the insulin pathway, better characterized, requires activation of phosphoinositide 3-kinase (PI3K) and atypical protein kinase (aPKC), muscle contraction seems to share insulin-activated components to increase glucose uptake. This study aimed to investigate the interrelation between the pathway involved in glucose uptake evoked by insulin and muscle contraction. Isolated muscle of rats was treated with solvent (control), insulin, wortmannin (PI3K inhibitor) and the combination of insulin plus wortmannin. After treatment, muscles were electrically stimulated (contracted) or remained at rest. Glucose transporter 4 (GLUT4) localization, glucose uptake and phospho-aPKC (aPKC activated form) were assessed. Muscle contraction and insulin increased glucose uptake in all conditions when compared with controls not stimulating an effect that was accompanied by an increase in GLUT4 and of phospho-aPKC at the muscle membrane. Contracted muscles treated with insulin did not show additive effects on glucose uptake or aPKC activity compared with the response when these stimuli were applied alone. Inhibition of PI3K blocked insulin effect on glucose uptake and aPKC but not in the contractile response. Thus, muscle contraction seems to stimulate aPKC and glucose uptake independently of PI3K. Therefore, aPKC may be a convergence point and a rate limit step in the pathway by which, insulin and contraction, increase glucose uptake in skeletal muscle.

  3. Determining the effects of electrical stimulation on functional recovery of denervated rat gastrocnemius muscle using motor unit number estimation.

    PubMed

    Willand, Michael P; Holmes, Michael; Bain, James R; Fahnestock, Margaret; de Bruin, Hubert

    2011-01-01

    The use of electrical muscle stimulation to treat denervated muscle prior to delayed reinnervation has been widely debated. There is evidence showing both positive and negative results following different protocols of electrical stimulation. In this study we investigated the role electrical stimulation has on muscle reinnervation following immediate and delayed nerve repair using motor unit estimation techniques. Rat gastrocnemius muscle was denervated and repaired using the peroneal nerve either immediately or following three-months with and without electrical stimulation. Motor unit counts, average motor unit sizes, and maximum compound action potentials were measured three-months following peroneal nerve repair. Motor unit counts in animals that were denervated and stimulated were significantly higher than those that were denervated and not stimulated. Both average motor unit sizes and maximum compound action potentials showed no significant differences between denervated and denervated-stimulated animals. These results provide evidence that electrical stimulation prior to delayed nerve repair increases muscle receptivity to regenerating axons and may be a worthwhile treatment for peripheral nerve injuries.

  4. Effect of Electrical Stimulation of the Suprahyoid Muscles in Brain-Injured Patients with Dysphagia.

    PubMed

    Beom, Jaewon; Oh, Byung-Mo; Choi, Kyoung Hyo; Kim, Won; Song, Young Jin; You, Dae Sang; Kim, Sang Jun; Han, Tai Ryoon

    2015-08-01

    The purpose of this study is to determine whether neuromuscular electrical stimulation of the suprahyoid muscle is effective compared to that of the infrahyoid muscle in brain-injured patients with dysphagia. A total of 132 patients with stroke, traumatic brain injury, or brain tumor in 2 university hospitals were allocated to 2 groups: those who received electrical stimulation therapy (EST) on the suprahyoid muscles (SM group, n = 66) and those who received EST with one pair of electrodes on the suprahyoid muscle and the other pair on the infrahyoid muscle (SI group, n = 66). Patients received 11.2 ± 3.4 sessions of electrical stimulation in the SM group and 11.9 ± 3.4 sessions in the SI group. The functional dysphagia scale (FDS), swallow function score (SFS), supraglottic penetration, and subglottic aspiration were measured using videofluoroscopic swallowing study. FDS scores decreased from 42.0 ± 19.1 to 32.3 ± 17.8 in the SM group and from 44.8 ± 17.4 to 32.9 ± 18.8 in the SI group by per-protocol (PP) analysis, and those decreased from 41.2 ± 20.9 to 34.5 ± 20.3 in the SM group and from 44.3 ± 19.1 to 35.7 ± 20.5 in the SI group by intention-to-treat (ITT) analysis, after electrical stimulation (p < 0.001 for each). SFSs increased from 3.3 ± 1.8 to 4.2 ± 1.6 in the SM group and from 2.8 ± 1.8 to 4.0 ± 1.8 in the SI group by PP analysis, and those increased from 3.3 ± 1.6 to 3.9 ± 1.6 in the SM group and from 2.8 ± 1.9 to 3.6 ± 2.0 in the SI group by ITT analysis, after electrical stimulation (p < 0.001, respectively). However, changes in FDS scores, SFSs, penetration, and aspiration were comparable between the SM and the SI groups. The results suggest that both SM and SI therapies induced similar improvements in swallowing function in brain-injured patients.

  5. Extracellular calcium sensing in rat aortic vascular smooth muscle cells

    SciTech Connect

    Smajilovic, Sanela; Hansen, Jakob Lerche; Christoffersen, Tue E.H.

    2006-10-06

    Extracellular calcium (Ca2+o) can act as a first messenger in many cell types through a G protein-coupled receptor, calcium-sensing receptor (CaR). It is still debated whether the CaR is expressed in vascular smooth muscle cells (VSMCs). Here, we report the expression of CaR mRNA and protein in rat aortic VSMCs and show that Ca2+o stimulates proliferation of the cells. The effects of Ca2+o were attenuated by pre-treatment with MAPK kinase 1 (MEK1) inhibitor, as well as an allosteric modulator, NPS 2390. Furthermore, stimulation of the VSMCs with Ca2+o-induced phosphorylation of ERK1/2, but surprisingly did not cause inositol phosphate accumulation. We were not able to conclusively state that the CaR mediates Ca2+o-induced cell proliferation. Rather, an additional calcium-sensing mechanism may exist. Our findings may be of importance with regard to atherosclerosis, an inflammatory disease characterized by abnormal proliferation of VSMCs and high local levels of calcium.

  6. Cell accumulation in the junctional region of denervated muscle

    PubMed Central

    1987-01-01

    If skeletal muscles are denervated, the number of mononucleated cells in the connective tissue between muscle fibers increases. Since interstitial cells might remodel extracellular matrix, and since extracellular matrix in nerve and muscle plays a direct role in reinnervation of the sites of the original neuromuscular junctions, we sought to determine whether interstitial cell accumulation differs between junctional and extrajunctional regions of denervated muscle. We found in muscles from frog and rat that the increase in interstitial cell number was severalfold (14-fold for frog, sevenfold for rat) greater in the vicinity of junctional sites than in extrajunctional regions. Characteristics of the response at the junctional sites of frog muscles are as follows. During chronic denervation, the accumulation of interstitial cells begins within 1 wk and it is maximal by 3 wk. Reinnervation 1-2 wk after nerve damage prevents the maximal accumulation. Processes of the cells form a multilayered veil around muscle fibers but make little, if any, contact with the muscle cell or its basal lamina sheath. The results of additional experiments indicate that the accumulated cells do not originate from terminal Schwann cells or from muscle satellite cells. Most likely the cells are derived from fibroblasts that normally occupy the space between muscle fibers and are known to make and degrade extracellular matrix components. PMID:3491825

  7. Regulation of the nuclear export of the transcription factor NFATc1 by protein kinases after slow fibre type electrical stimulation of adult mouse skeletal muscle fibres.

    PubMed

    Shen, Tiansheng; Cseresnyés, Zoltán; Liu, Yewei; Randall, William R; Schneider, Martin F

    2007-03-01

    The transcription factor nuclear factor of activated T cells (NFAT)c1 has been shown to be involved in turning on slow skeletal muscle fibre gene expression. Previous studies from our laboratory have characterized the stimulation pattern-dependent nuclear import and resting shuttling of NFATc1-green fluorescent protein (GFP) in flexor digitorum brevis (FDB) muscle fibres from adult mouse. In this study, we use viral expression of the transcription factor NFATc1-GFP fusion protein to investigate the mechanisms underlying the nuclear export of the NFATc1-GFP that accumulated in the nuclei of cultured dissociated adult mouse FDB muscle fibres during slow-twitch fibre type electrical stimulation. In these studies, we found that inhibition of either glycogen synthase kinase 3beta (GSK3beta) or casein kinase 1 or 2 (CK1/2) markedly slowed the decay of nuclear NFATc1-GFP after cessation of muscle fibre electrical stimulation, whereas inhibition of casein kinase 1delta, p38 mitogen-activated protein kinase, c-Jun N-terminal kinase and protein kinase A had little effect. Simultaneous inhibition of GSK3beta and CK1/2 completely blocked the nuclear export of NFATc1-GFP after muscle activity. We also developed a simplified model of NFATc1 phosphorylation/dephosphorylation and nuclear fluxes, and used this model to simulate the observed time courses of nuclear NFATc1-GFP with and without NFATc1 kinase inhibition. Our results suggest that GSK3beta and CK1/2 are the major protein kinases that contribute to the removal of NFATc1 that accumulates in muscle fibre nuclei during muscle activity, and that GSK3beta and CK1/2 are responsible for phosphorylating NFATc1 in muscle nuclei in a complementary or synergistic fashion.

  8. Autofluorescent particles of human uterine muscle cells.

    PubMed Central

    Gosden, R. G.; Hawkins, H. K.; Gosden, C. A.

    1978-01-01

    Smooth muscle tissue collected from the uterine fundus of 24 patients undergoing hysterectomy was examined for chromolipoid pigments by histochemical and electron microscopic techniques. Certain cytoplasmic particles were found, mainly in smooth muscle cells, which exhibited characteristic autofluorescence, sudanophilia, and acid phosphatase activity but did not correspond to any typical pigment described previously. These particles were present in all subjects and they tended to increase in number with age. Chemical tests on tissue lipid extracts failed to prove that vitamin A was responsible for the fluorescence. The ultrastructural appearance of the particles somewhat variable, but most particles were rounded and of low electron density, with a lucent central space and dense bodies, probably lysosomes, at the periphery. The whole complex was enclosed by a single trilaminar membrane. Images Figure 5 Figure 1 Figure 2 Figure 6 Figure 7 Figure 3 Figure 8 Figure 4 PMID:645817

  9. Exercise and amino acid anabolic cell signaling and the regulation of skeletal muscle mass.

    PubMed

    Pasiakos, Stefan M

    2012-07-01

    A series of complex intracellular networks influence the regulation of skeletal muscle protein turnover. In recent years, studies have examined how cellular regulators of muscle protein turnover modulate metabolic mechanisms contributing to the loss, gain, or conservation of skeletal muscle mass. Exercise and amino acids both stimulate anabolic signaling potentially through several intracellular pathways including the mammalian target of rapamycin complex 1 and the mitogen activated protein kinase cell signaling cascades. As novel molecular regulators of muscle integrity continue to be explored, a contemporary analysis of the literature is required to understand the metabolic mechanisms by which contractile forces and amino acids affect cellular process that contribute to long-term adaptations and preservation of muscle mass. This article reviews the literature related to how exercise and amino acid availability affect cellular regulators of skeletal muscle mass, especially highlighting recent investigations that have identified mechanisms by which contractile forces and amino acids modulate muscle health. Furthermore, this review will explore integrated exercise and nutrition strategies that promote the maintenance of muscle health by optimizing exercise, and amino acid-induced cell signaling in aging adults susceptible to muscle loss.

  10. Lkb1 deletion promotes ectopic lipid accumulation in muscle progenitor cells and mature muscles.

    PubMed

    Shan, Tizhong; Zhang, Pengpeng; Bi, Pengpeng; Kuang, Shihuan

    2015-05-01

    Excessive intramyocellular triglycerides (muscle lipids) are associated with reduced contractile function, insulin resistance, and Type 2 diabetes, but what governs lipid accumulation in muscle is unclear. Here we report a role of Lkb1 in regulating lipid metabolism in muscle stem cells and their descendent mature muscles. We used Myod(Cre) and Lkb1(flox/flox) mice to specifically delete Lkb1 in myogenic cells including stem and differentiated cells, and examined the lipid accumulation and gene expression of myoblasts cultured from muscle stem cells (satellite cells). Genetic deletion of Lkb1 in myogenic progenitors led to elevated expression of lipogenic genes and ectopic lipid accumulation in proliferating myoblasts. Interestingly, the Lkb1-deficient myoblasts differentiated into adipocyte-like cells upon adipogenic induction. However, these adipocyte-like cells maintained myogenic gene expression with reduced ability to form myotubes efficiently. Activation of AMPK by AICAR prevented ectopic lipid formation in the Lkb1-null myoblasts. Notably, Lkb1-deficient muscles accumulated excessive lipids in vivo in response to high-fat diet feeding. These results demonstrate that Lkb1 acts through AMPK to limit lipid deposition in muscle stem cells and their derivative mature muscles, and point to the possibility of controlling muscle lipid content using AMPK activating drugs.

  11. The role of satellite cells in muscle hypertrophy.

    PubMed

    Blaauw, Bert; Reggiani, Carlo

    2014-02-01

    The role of satellite cells in muscle hypertrophy has long been a debated issue. In the late 1980s it was shown that proteins remain close to the myonucleus responsible for its synthesis, giving rise to the idea of a nuclear domain. This, together with the observation that during various models of muscle hypertrophy there is an activation of the muscle stem cells, i.e. satellite cells, lead to the idea that satellite cell activation is required for muscle hypertrophy. Thus, satellite cells are not only responsible for muscle repair and regeneration, but also for hypertrophic growth. Further support for this line of thinking was obtained after studies showing that irradiation of skeletal muscle, and therefore elimination of all satellite cells, completely prevented overload-induced hypertrophy. Recently however, using different transgenic approaches, it has become clear that muscle hypertrophy can occur without a contribution of satellite cells, even though in most situations of muscle hypertrophy satellite cells are activated. In this review we will discuss the contribution of satellite cells, and other muscle-resident stem cells, to muscle hypertrophy both in mice as well as in humans.

  12. Functional heterogeneity of side population cells in skeletal muscle

    SciTech Connect

    Uezumi, Akiyoshi; Ojima, Koichi; Fukada, So-ichiro; Ikemoto, Madoka; Masuda, Satoru; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi . E-mail: takeda@ncnp.go.jp

    2006-03-17

    Skeletal muscle regeneration has been exclusively attributed to myogenic precursors, satellite cells. A stem cell-rich fraction referred to as side population (SP) cells also resides in skeletal muscle, but its roles in muscle regeneration remain unclear. We found that muscle SP cells could be subdivided into three sub-fractions using CD31 and CD45 markers. The majority of SP cells in normal non-regenerating muscle expressed CD31 and had endothelial characteristics. However, CD31{sup -}CD45{sup -} SP cells, which are a minor subpopulation in normal muscle, actively proliferated upon muscle injury and expressed not only several regulatory genes for muscle regeneration but also some mesenchymal lineage markers. CD31{sup -}CD45{sup -} SP cells showed the greatest myogenic potential among three SP sub-fractions, but indeed revealed mesenchymal potentials in vitro. These SP cells preferentially differentiated into myofibers after intramuscular transplantation in vivo. Our results revealed the heterogeneity of muscle SP cells and suggest that CD31{sup -}CD45{sup -} SP cells participate in muscle regeneration.

  13. Motor unit recruitment when neuromuscular electrical stimulation is applied over a nerve trunk compared with a muscle belly: triceps surae.

    PubMed

    Bergquist, A J; Clair, J M; Collins, D F

    2011-03-01

    Neuromuscular electrical stimulation (NMES) can be delivered over a nerve trunk or muscle belly and can generate contractions by activating motor (peripheral pathway) and sensory (central pathway) axons. In the present experiments, we compared the peripheral and central contributions to plantar flexion contractions evoked by stimulation over the tibial nerve vs. the triceps surae muscles. Generating contractions through central pathways follows Henneman's size principle, whereby low-threshold motor units are activated first, and this may have advantages for rehabilitation. Statistical analyses were performed on data from trials in which NMES was delivered to evoke 10-30% maximum voluntary torque 2-3 s into the stimulation (Time(1)). Two patterns of stimulation were delivered: 1) 20 Hz for 8 s; and 2) 20-100-20 Hz for 3-2-3 s. Torque and soleus electromyography were quantified at the beginning (Time(1)) and end (Time(2); 6-7 s into the stimulation) of each stimulation train. H reflexes (central pathway) and M waves (peripheral pathway) were quantified. Motor unit activity that was not time-locked to each stimulation pulse as an M wave or H reflex ("asynchronous" activity) was also quantified as a second measure of central recruitment. Torque was not different for stimulation over the nerve or the muscle. In contrast, M waves were approximately five to six times smaller, and H reflexes were approximately two to three times larger during NMES over the nerve vs. the muscle. Asynchronous activity increased by 50% over time, regardless of the stimulation location or pattern, and was largest during NMES over the muscle belly. Compared with NMES over the triceps surae muscles, NMES over the tibial nerve produced contractions with a relatively greater central contribution, and this may help reduce muscle atrophy and fatigue when NMES is used for rehabilitation.

  14. Mechanical stimulation of skeletal muscle increases prostaglandin F2(alpha) synthesis and cyclooxygenase activity by a pertussis toxin sensitive mechanism

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.; Shansky, Janet; Solerssi, Rosa; Chromiak, Joseph

    1992-01-01

    Repetitive mechanical stimulation of differentiated skeletal muscle in tissue culture increases the production of prostaglandin F(sub 2(alpha)), an anabolic stimulator of myofiber growth. Within 4 h of initiating mechanical activity, the activity of cyclooxygenase, a regulatory enzyme in prostaglandin synthesis, was increased 82% (P is less than .005), and this increase was maintained for at least 24 h. Kinetic analysis of the stretch-activated cyclooxygenase indicated a two to three-fold decrease in the enzyme's K(sub m) with no change in V(sub max). The stretch-induced increase in enzymatic activity was not inhibited by cycloheximide, was independent of cellular electrical activity (tetrodotoxin-insensitive), but was prevented by the G protein inhibitor pertussis toxin. Pertussis toxin also inhibited the stretch-induced increases in PGF(sub 2(alpha)) production, and cell growth. It is concluded that stretch of skeletal muscle increases the synthesis of the anabolic modulator PGF(sub 2(alpha)) by a G protein-dependent process which involves activation of cyclooxygenase by a posttranslational mechanism.

  15. HDAC4 promotes Pax7-dependent satellite cell activation and muscle regeneration

    PubMed Central

    Choi, Moon-Chang; Ryu, Soyoung; Hao, Rui; Wang, Bin; Kapur, Meghan; Fan, Chen-Ming; Yao, Tso-Pang

    2014-01-01

    During muscle regeneration, the transcription factor Pax7 stimulates the differentiation of satellite cells (SCs) toward the muscle lineage but restricts adipogenesis. Here, we identify HDAC4 as a regulator of Pax7-dependent muscle regeneration. In HDAC4-deficient SCs, the expression of Pax7 and its target genes is reduced. We identify HDAC4-regulated Lix1 as a Pax7 target gene required for SC proliferation. HDAC4 inactivation leads to defective SC proliferation, muscle regeneration, and aberrant lipid accumulation. Further, expression of the brown adipose master regulator Prdm16 and its inhibitory microRNA-133 are also deregulated. Thus, HDAC4 is a novel regulator of Pax7-dependent SC proliferation and potentially fate determination in regenerating muscle. PMID:25205686

  16. Fetal muscle-derived cells can repair dystrophic muscles in mdx mice.

    PubMed

    Auda-Boucher, Gwenola; Rouaud, Thierry; Lafoux, Aude; Levitsky, Dmitri; Huchet-Cadiou, Corinne; Feron, Marie; Guevel, Laetitia; Talon, Sophie; Fontaine-Pérus, Josiane; Gardahaut, Marie-France

    2007-03-10

    We have previously reported that CD34(+) cells purified from mouse fetal muscles can differentiate into skeletal muscle in vitro and in vivo when injected into muscle tissue of dystrophic mdx mice. In this study, we investigate the ability of such donor cells to restore dystrophin expression, and to improve the functional muscle capacity of the extensor digitorum longus muscle (EDL) of mdx mice. For this purpose green fluorescent-positive fetal GFP(+)/CD34(+) cells or desmin(+)/(-)LacZ/CD34(+) cells were transplanted into irradiated or non-irradiated mdx EDL muscle. Donor fetal muscle-derived cells predominantly fused with existing fibers. Indeed more than 50% of the myofibers of the host EDL contained donor nuclei delivering dystrophin along 80-90% of the length of their sarcolemma. The presence of significant amounts of dystrophin (about 60-70% of that found in a control wild-type mouse muscle) was confirmed by Western blot analyses. Dystrophin expression also outcompeted that of utrophin, as revealed by a spatial shift in the distribution of utrophin. At 1 month post-transplant, the recipient muscle appeared to have greater resistance to fatigue than control mdx EDL muscle during repeated maximal contractions.

  17. Fuzzy control with amplitude/pulse-width modulation of nerve electrical stimulation for muscle force control.

    PubMed

    Lin, C-C K; Liu, W-C; Chan, C-C; Ju, M-S

    2012-04-01

    The main goal of this study was to study the performance of fuzzy logic controllers combined with simplified hybrid amplitude/pulse-width (AM/PW) modulation to regulate muscle force via nerve electrical stimulation. The recruitment curves with AM/PW and AM modulations were constructed for the calf muscles of rabbits. Integrated with the modulation methods, a proportional-integral-derivative (PID) and three fuzzy logic controllers were designed and applied for the electrical stimulation of tibial nerves to control the ankle torque under isometric conditions. The performance of the two modulation methods combined with the four controllers was compared when the ankle was fixed at three positions for both in vivo experiments and model simulations using a nonlinear muscle model. For the animal experiments, AM/PW modulation performed better than AM modulation alone. The fuzzy PI controller performed marginally better and was resistant to external noises, though it tended to have a larger overshoot. The performance of the controllers had a similar trend in the three different joint positions, and the simulation results with the nonlinear model matched the experimental results well. In conclusion, AM/PW modulation improved controller performance, while the contribution of fuzzy logic was only marginal.

  18. Muscle satellite cells are a functionally heterogeneous population in both somite-derived and branchiomeric muscles.

    PubMed

    Ono, Yusuke; Boldrin, Luisa; Knopp, Paul; Morgan, Jennifer E; Zammit, Peter S

    2010-01-01

    Skeletal muscles of body and limb are derived from somites, but most head muscles originate from cranial mesoderm. The resident stem cells of muscle are satellite cells, which have the same embryonic origin as the muscle in which they reside. Here, we analysed satellite cells with a different ontology, comparing those of the extensor digitorum longus (EDL) of the limb with satellite cells from the masseter of the head. Satellite cell-derived myoblasts from MAS and EDL muscles had distinct gene expression profiles and masseter cells usually proliferated more and differentiated later than those from EDL. When transplanted, however, masseter-derived satellite cells regenerated limb muscles as efficiently as those from EDL. Clonal analysis showed that functional properties differed markedly between satellite cells: ranging from clones that proliferated extensively and gave rise to both differentiated and self-renewed progeny, to others that divided minimally before differentiating completely. Generally, masseter-derived clones were larger and took longer to differentiate than those from EDL. This distribution in cell properties was preserved in both EDL-derived and masseter-derived satellite cells from old mice, although clones were generally less proliferative. Satellite cells, therefore, are a functionally heterogeneous population, with many occupants of the niche exhibiting stem cell characteristics in both somite-derived and branchiomeric muscles.

  19. Intramedullary Pressure and Matrix Strain Induced by Oscillatory Skeletal Muscle Stimulation and its Potential in Adaptation

    PubMed Central

    Qin, Yi-Xian; Lam, Hoyan

    2010-01-01

    Intramedullary pressure (ImP) and low-level bone strain induced by oscillatory muscle stimulation (MS) has the potential to mitigate bone loss induced by disuse osteopenia, i.e., hindlimb suspension (HLS). To test this hypothesis, we evaluated a) MS induced ImP and bone strain as function of stimulation frequency, and b) the adaptive responses to functional disuse, and disuse plus 1Hz and 20Hz stimulation in vivo. Femoral ImP and bone strain generated by MS were measured in the frequencies of 1Hz-100Hz in four rats. Forty retired breeder rats were used for the in vivo HLS study. The quadriceps muscle was stimulated at frequencies of 1 Hz and 20 Hz, 10min/d for 4 weeks. The metaphyseal trabecular bone quantity and microstructure at the distal femur were evaluated using μCT, while bone formation indices were analyzed using histomorphometric techniques. Oscillatory MS generated a maximum ImP of 45±9 mmHg at 20 Hz and produced a maximum matrix strain of 128±19 με at 10 Hz. Our analyses from the in vivo study showed that MS at 20 Hz was able to attenuate trabecular bone loss and partially maintain the microstructure induced by HLS. Conversely, there was no evidence of an adaptive effect of stimulation at 1 Hz on disused skeleton. The results suggested that oscillatory MS regulates fluid dynamics and mechanical strain in bone, which serves as a critical mediator of adaptation. These results clearly demonstrated the ability of MS in attenuating bone loss from the disuse osteopenia and could hold potential in mitigating skeletal degradation imposed by conditions of disuse, which may serve as a biomechanical intervention in clinic application. PMID:19081096

  20. Acromiohumeral Distance During Neuromuscular Electrical Stimulation of the Lower Trapezius and Serratus Anterior Muscles in Healthy Participants

    PubMed Central

    Bdaiwi, Alya H.; Mackenzie, Tanya Anne; Herrington, Lee; Horsley, Ian; Cools, Ann M.

    2015-01-01

    Context Compromise to the acromiohumeral distance has been reported in participants with subacromial impingement syndrome compared with healthy participants. In clinical practice, patients with subacromial shoulder impingement are given strengthening programs targeting the lower trapezius (LT) and serratus anterior (SA) muscles to increase scapular posterior tilt and upward rotation. We are the first to use neuromuscular electrical stimulation to stimulate these muscle groups and evaluate how the muscle contraction affects the acromiohumeral distance. Objective To investigate if electrical muscle stimulation of the LT and SA muscles, both separately and simultaneously, increases the acromiohumeral distance and to identify which muscle-group contraction or combination most influences the acromiohumeral distance. Design Controlled laboratory study. Setting Human performance laboratory. Patients or Other Participants Twenty participants (10 men and 10 women, age = 26.9 ± 8.0 years, body mass index = 23.8) were screened. Intervention(s) Neuromuscular electrical stimulation of the LT and SA. Main Outcome Measure(s) Ultrasound measurement of the acromiohumeral distance. Results Acromiohumeral distance increased during contraction via neuromuscular electrical stimulation of the LT muscle (t19 = −3.89, P = .004), SA muscle (t19 = −7.67, P = .001), and combined LT and SA muscles (t19 = −5.09, P = .001). We observed no differences in the increased acromiohumeral distance among the 3 procedures (F2,57 = 3.109, P = .08). Conclusions Our results supported the hypothesis that the muscle force couple around the scapula is important in rehabilitation and scapular control and influences acromiohumeral distance. PMID:25933249

  1. Novel insight into stem cell trafficking in dystrophic muscles.

    PubMed

    Farini, Andrea; Villa, Chiara; Manescu, Adrian; Fiori, Fabrizio; Giuliani, Alessandra; Razini, Paola; Sitzia, Clementina; Del Fraro, Giulia; Belicchi, Marzia; Meregalli, Mirella; Rustichelli, Franco; Torrente, Yvan

    2012-01-01

    Recently published reports have described possible cellular therapy approaches to regenerate muscle tissues using arterial route delivery. However, the kinetic of distribution of these migratory stem cells within injected animal muscular dystrophy models is unknown. Using living X-ray computed microtomography, we established that intra-arterially injected stem cells traffic to multiple muscle tissues for several hours until their migration within dystrophic muscles. Injected stem cells express multiple traffic molecules, including VLA-4, LFA-1, CD44, and the chemokine receptor CXCR4, which are likely to direct these cells into dystrophic muscles. In fact, the majority of intra-arterially injected stem cells access the muscle tissues not immediately after the injection, but after several rounds of recirculation. We set up a new, living, 3D-imaging approach, which appears to be an important way to investigate the kinetic of distribution of systemically injected stem cells within dystrophic muscle tissues, thereby providing supportive data for future clinical applications.

  2. Bradykinin stimulation of phosphoinositide hydrolysis in guinea-pig ileum longitudinal muscle.

    PubMed Central

    Ransom, R. W.; Goodman, C. B.; Young, G. S.

    1992-01-01

    1. Bradykinin (BK)-induced contraction of ileal smooth muscle is assumed to be due to phosphoinositide hydrolysis but this has never been reported. We have investigated whether BK receptors are linked to this transduction mechanism in guinea-pig ileum longitudinal muscle and determined whether these receptors are equivalent to those labelled in [3H]-BK binding assays. 2. In membranes prepared from longitudinal muscle, [3H]-BK bound to a single class of sites with high affinity. Characterization of the binding with BK analogues indicated that the radioligand selectivity labelled a B2 type receptor. 3. BK significantly elevated tissue levels of [3H]-inositol phosphates in longitudinal muscle slices preincubated with [3H]-myo-inositol. The agonists potencies of BK, Lys-BK, Met-Lys-BK, Tyr5-BK and Tyr8-BK were in agreement with their relative potencies in the binding assay. The B1 receptor agonist des-Arg9-BK, did not stimulate inositol phosphate production. The response to BK was blocked by known B2 receptor antagonists but not by the B1 antagonist des-Arg9, Leu8-BK. 4. BK-induced phosphoinositide hydrolysis was unaffected by exposure of muscle slices to either atropine or indomethacin. 5. The results indicate that the B2 receptors linked to phosphoinositide turnover in ileal longitudinal muscle exhibit properties similar to those involved in contractile responses. Also, the receptor mediating the phosphoinositide response is likely to be that labelled in the [3H]-BK binding studies. PMID:1324057

  3. Transient stimulation expands superior antitumor T cells for adoptive therapy

    PubMed Central

    Kagoya, Yuki; Nakatsugawa, Munehide; Ochi, Toshiki; Guo, Tingxi; Anczurowski, Mark; Saso, Kayoko; Butler, Marcus O.

    2017-01-01

    Adoptive cell therapy is a potentially curative therapeutic approach for patients with cancer. In this treatment modality, antitumor T cells are exponentially expanded in vitro prior to infusion. Importantly, the results of recent clinical trials suggest that the quality of expanded T cells critically affects their therapeutic efficacy. Although anti-CD3 mAb-based stimulation is widely used to expand T cells in vitro, a protocol to generate T cell grafts for optimal adoptive therapy has yet to be established. In this study, we investigated the differences between T cell stimulation mediated by anti–CD3/CD28 mAb–coated beads and cell-based artificial antigen-presenting cells (aAPCs) expressing CD3/CD28 counter-receptors. We found that transient stimulation with cell-based aAPCs, but not prolonged stimulation with beads, resulted in the superior expansion of CD8+ T cells. Transiently stimulated CD8+ T cells maintained a stem cell–like memory phenotype and were capable of secreting multiple cytokines significantly more efficiently than chronically stimulated T cells. Importantly, the chimeric antigen receptor–engineered antitumor CD8+ T cells expanded via transient stimulation demonstrated superior persistence and antitumor responses in adoptive immunotherapy mouse models. These results suggest that restrained stimulation is critical for generating T cell grafts for optimal adoptive immunotherapy for cancer. PMID:28138559

  4. Setup and procedure for online identification of electrically stimulated muscle with Matlab Simulink.

    PubMed

    Ponikvar, M; Munih, M

    2001-09-01

    This paper first describes a laboratory setup for biomechanical experiments that runs within the universal simulation environment Matlab Simulink. The overall system comprises a personal computer, two AMTI (Advanced Mechanical Technology, Inc., Watertown, MA 02472) force plates, Parotec force-sensor shoe insoles, Optotrak system for noncontact three-dimensional (3-D)-position measuring, and a computer-controlled four-channel electrical stimulator. Conceptually, the most important application is implementation of closed-loop electrical stimulation of intact and paralyzed subjects in the laboratory. Second, the system was tested in real-time muscle model identification procedure during a standing experiment. The plantarflexors of three nonimpaired subjects were excited with pseudorandom binary sequences (PRBSs) with small deviations around selected operating points. Electrically stimulated muscles were presented with a linear local dynamic block that was identified with a recursive least-square method (RARX). RARX block was designed with fundamental Matlab Simulink blocks that support real-time operation. Introduced was online estimation of model output, which offers a great manner of instant model validation. Two modes of operation with online validation were tested. In the first mode, the operating point for selected excitation level was identified online. In the second mode, the operating point was measured in preceding experiments. Both procedures resulted in satisfying second-order models that will be used in the adaptive controller design.

  5. Effectiveness of daily eccentric contractions induced via kilohertz frequency transcutaneous electrical stimulation on muscle atrophy.

    PubMed

    Tanaka, Minoru; Nakanishi, Ryosuke; Murakami, Shinichiro; Fujita, Naoto; Kondo, Hiroyo; Ishihara, Akihiko; Roy, Roland R; Fujino, Hidemi

    2016-01-01

    The effects of daily repeated bouts of concentric, isometric, or eccentric contractions induced by high frequency (kilohertz) transcutaneous electrical stimulation in ameliorating atrophy of the soleus muscle in hindlimb unloaded rats were determined. Five groups of male rats were studied: control, hindlimb unloaded for 2 weeks (HU), or HU plus two daily bouts of concentric, isometric, or eccentric high-frequency electrical stimulation-induced contractions of the calf musculature. Soleus mass and fiber size were smaller, the levels of phosphorylated Akt1 and FoxO3a lower, and atrogin-1 and ubiquitinated proteins higher in the HU, and the HU plus concentric or isometric contraction groups than in the control group. In contrast, daily bouts of eccentric contractions maintained these values at near control levels and all measures were significantly different from all other HU groups. These results indicate that daily bouts of eccentric contractions induced by high-frequency stimulation inhibited the ubiquitin-proteasome catabolic pathway and enhanced the Akt1/FoxO3a anabolic pathway that resulted in a prevention of the atrophic response of the soleus muscle to chronic unloading.

  6. Traction in smooth muscle cells varies with cell spreading

    NASA Technical Reports Server (NTRS)

    Tolic-Norrelykke, Iva Marija; Wang, Ning

    2005-01-01

    Changes in cell shape regulate cell growth, differentiation, and apoptosis. It has been suggested that the regulation of cell function by the cell shape is a result of the tension in the cytoskeleton and the distortion of the cell. Here we explore the association between cell-generated mechanical forces and the cell morphology. We hypothesized that the cell contractile force is associated with the degree of cell spreading, in particular with the cell length. We measured traction fields of single human airway smooth muscle cells plated on a polyacrylamide gel, in which fluorescent microbeads were embedded to serve as markers of gel deformation. The traction exerted by the cells at the cell-substrate interface was determined from the measured deformation of the gel. The traction was measured before and after treatment with the contractile agonist histamine, or the relaxing agonist isoproterenol. The relative increase in traction induced by histamine was negatively correlated with the baseline traction. On the contrary, the relative decrease in traction due to isoproterenol was independent of the baseline traction, but it was associated with cell shape: traction decreased more in elongated than in round cells. Maximum cell width, mean cell width, and projected area of the cell were the parameters most tightly coupled to both baseline and histamine-induced traction in this study. Wide and well-spread cells exerted larger traction than slim cells. These results suggest that cell contractility is controlled by cell spreading.

  7. Mechanical forces and their second messengers in stimulating cell growth in vitro

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.

    1992-01-01

    Mechanical forces play an important role in modulating the growth of a number of different tissues including skeletal muscle, smooth muscle, cardiac muscle, bone, endothelium, epithelium, and lung. As interest increases in the molecular mechanisms by which mechanical forces are transduced into growth alterations, model systems are being developed to study these processes in tissue culture. This paper reviews the current methods available for mechanically stimulating tissue cultured cells. It then outlines some of the putative 'mechanogenic' second messengers involved in altering cell growth. Not surprisingly, many mechanogenic second messengers are the same as those involved in growth factor-induced cell growth. It is hypothesized that from an evolutionary standpoint, some second messenger systems may have initially evolved for unicellular organisms to respond to physical forces such as gravity and mechanical perturbation in their environment. As multicellular organisms came into existence, they appropriated these mechanogenic second messenger cascades for cellular regulation by growth factors.

  8. Role of muscle stem cells during skeletal regeneration.

    PubMed

    Abou-Khalil, Rana; Yang, Frank; Lieu, Shirley; Julien, Anais; Perry, Jaselle; Pereira, Catia; Relaix, Frédéric; Miclau, Theodore; Marcucio, Ralph; Colnot, Céline

    2015-05-01

    Although the importance of muscle in skeletal regeneration is well recognized clinically, the mechanisms by which muscle supports bone repair have remained elusive. Muscle flaps are often used to cover the damaged bone after traumatic injury yet their contribution to bone healing is not known. Here, we show that direct bone-muscle interactions are required for periosteum activation and callus formation, and that muscle grafts provide a source of stem cells for skeletal regeneration. We investigated the role of satellite cells, the muscle stem cells. Satellite cells loss in Pax7(-/-) mice and satellite cell ablation in Pax7(Cre) (ERT) (2/) (+) ;DTA(f/f) mice impaired bone regeneration. Although satellite cells did not contribute as a large source of cells endogenously, they exhibited a potential to contribute to bone repair after transplantation. The fracture healing phenotype in Pax7(Cre) (ERT) (2/) (+) ;DTA(f/f) mice was associated with decreased bone morphogenetic proteins (BMPs), insulin-like growth factor 1, and fibroblast growth factor 2 expression that are normally upregulated in response to fracture in satellite cells. Exogenous rhBMP2 improved bone healing in Pax7(Cre) (ERT) (2/) (+) ;DTA(f/f) mice further supporting the role of satellite cells as a source of growth factors. These results provide the first functional evidence for a direct contribution of muscle to bone regeneration with important clinical implications as it may impact the use of muscle flaps, muscle stem cells, and growth factors in orthopedic applications.

  9. Satellite cells from dystrophic muscle retain regenerative capacity.

    PubMed

    Boldrin, Luisa; Zammit, Peter S; Morgan, Jennifer E

    2015-01-01

    Duchenne muscular dystrophy is an inherited disorder that is characterized by progressive skeletal muscle weakness and wasting, with a failure of muscle maintenance/repair mediated by satellite cells (muscle stem cells). The function of skeletal muscle stem cells resident in dystrophic muscle may be perturbed by being in an increasing pathogenic environment, coupled with constant demands for repairing muscle. To investigate the contribution of satellite cell exhaustion to this process, we tested the functionality of satellite cells isolated from the mdx mouse model of Duchenne muscular dystrophy. We found that satellite cells derived from young mdx mice contributed efficiently to muscle regeneration within our in vivo mouse model. To then test the effects of long-term residence in a dystrophic environment, satellite cells were isolated from aged mdx muscle. Surprisingly, they were as functional as those derived from young or aged wild type donors. Removing satellite cells from a dystrophic milieu reveals that their regenerative capacity remains both intact and similar to satellite cells derived from healthy muscle, indicating that the host environment is critical for controlling satellite cell function.

  10. Skeletal muscle protein synthesis in neonatal pigs is stimulated by A-ketoisocaproic acid, but not by norleucine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In neonatal pigs, skeletal muscle protein synthesis is stimulated when plasma leucine is increased within the physiological postprandial range. We previously have shown that valine and isoleucine were not able to stimulate protein synthesis when their plasma concentrations were elevated within the ...

  11. Endogenous mesenchymal stromal cells in bone marrow are required to preserve muscle function in mdx mice.

    PubMed

    Fujita, Ryo; Tamai, Katsuto; Aikawa, Eriko; Nimura, Keisuke; Ishino, Saki; Kikuchi, Yasushi; Kaneda, Yasufumi

    2015-03-01

    The physiological role of "endogenous" bone marrow (BM) mesenchymal stromal cells (MSCs) in tissue regeneration is poorly understood. Here, we show the significant contribution of unique endogenous BM-MSC populations to muscle regeneration in Duchenne muscular dystrophy (DMD) mice (mdx). Transplantation of BM cells (BMCs) from 10-week-old mdx into 3-4-week-old mdx mice increased inflammation and fibrosis and reduced muscle function compared with mdx mice that received BMCs from 10-week-old wild-type mice, suggesting that the alteration of BMC populations in mdx mice affects the progression of muscle pathology. Two distinct MSC populations in BM, that is, hematopoietic lineage (Lin)(-) /ckit(-) /CD106(+) /CD44(+) and Lin(-) /ckit(-) /CD106(+) /CD44(-) cells, were significantly reduced in 10-week-old mdx mice in disease progression. The results of a whole-transcriptome analysis indicated that these two MSC populations have distinct gene expression profiles, indicating that the Lin(-) /ckit(-) /CD106(+) /CD44(+) and Lin(-) /ckit(-) /CD106(+) /CD44(-) MSC populations are proliferative- and dormant-state populations in BM, respectively. BM-derived Lin(-) /CD106(+) /CD44(+) MSCs abundantly migrated to damaged muscles and highly expressed tumor necrosis factor-alpha-stimulated gene/protein-6 (TSG-6), an anti-inflammatory protein, in damaged muscles. We also demonstrated that TSG-6 stimulated myoblast proliferation. The injection of Lin(-) /ckit(-) /CD106(+) /CD44(+) MSCs into the muscle of mdx mice successfully ameliorated muscle dysfunction by decreasing inflammation and enhancing muscle regeneration through TSG-6-mediated activities. Thus, we propose a novel function of the unique endogenous BM-MSC population, which countered muscle pathology progression in a DMD model.

  12. Dynamic Foot Stimulation Attenuates Soleus Muscle Atrophy Induced by Hindlimb Unloading in Rats

    NASA Technical Reports Server (NTRS)

    Kyparos, Antonios; Feeback, Daniel L.; Layne, Charles S.; Martinez, Daniel A.; Clarke, Mark S. F.

    2004-01-01

    Unloading-induced myofiber atrophy is a phenomenon that occurs in the aging population, bed-ridden patients and astronauts. The objective of this study was to determine whether or not dynamic foot stimulation (DFS) applied to the plantar surface of the rat foot can serve as a countermeasure to the soleus muscle atrophy normally observed in hindlimb unloaded (HU) rats. Thirty mature adult (6-month-old) male Wistar rats were randomly assigned into ambulatory control (AMB), hindlimb unloaded alone (HU), or hindlimb unloaded with the application of DFS (HU+DFS) groups. A dynamic pattern of pressure was applied to the right foot of each HU animal using a specially fabricated boot containing an inflatable air bladder connected to a solenoid air pump controlled by a laptop computer. The anti-atrophic effects of DFS were quantified morphometrically in frozen cross-sections of soleus muscle stained using the metachromatic-ATPase fiber typing technique. Application of DFS during HU significantly counteracted the atrophic response observed in the soleus by preventing approximately 85% of the reduction in Type I myofiber cross-sectional area (CSA) observed during HU. However, DFS did not protect type II fibers of the soleus from HU-induced atrophy or any fiber type in the soleus muscle of the contralateral control leg of the DFS-treated HU animals. These results illustrate that the application of DFS to the rat foot is an effective countermeasure to soleus muscle atrophy induced by HU.

  13. Spatial factors and muscle spindle input influence the generation of neuromuscular responses to stimulation of the human foot

    NASA Astrophysics Data System (ADS)

    Layne, Charles S.; Forth, Katharine E.; Abercromby, Andrew F. J.

    2005-05-01

    Removal of the mechanical pressure gradient on the soles leads to physiological adaptations that ultimately result in neuromotor degradation during spaceflight. We propose that mechanical stimulation of the soles serves to partially restore the afference associated with bipedal loading and assists in attenuating the negative neuromotor consequences of spaceflight. A dynamic foot stimulus device was used to stimulate the soles in a variety of conditions with different stimulation locations, stimulation patterns and muscle spindle input. Surface electromyography revealed the lateral side of the sole elicited the greatest neuromuscular response in ankle musculature, followed by the medial side, then the heel. These responses were modified by preceding stimulation. Neuromuscular responses were also influenced by the level of muscle spindle input. These results provide important information that can be used to guide the development of a "passive" countermeasure that relies on sole stimulation and can supplement existing exercise protocols during spaceflight.

  14. Myogenic progenitors and imaging single-cell flow analysis: a model to study commitment of adult muscle stem cells.

    PubMed

    Trapecar, Martin; Kelc, Robi; Gradisnik, Lidija; Vogrin, Matjaz; Rupnik, Marjan Slak

    2014-12-01

    Research on skeletal muscles suffers from a lack of appropriate human models to study muscle formation and regeneration on the regulatory level of single cells. This hampers both basic understanding and the development of new therapeutic approaches. The use of imaging multicolour flow cytometry and myogenic stem cells can help fill this void by allowing researchers to visualize and quantify the reaction of individual cultured cells to bioactives or other physiological impulses. As proof of concept, we subjected human CD56+ satellite cells to reference bioactives follistatin and Malva sylvestris extracts and then used imaging multicolor flow cytometry to visualize the stepwise activation of myogenic factors MyoD and myogenin in individual cells. This approach enabled us to evaluate the potency of these bioactives to stimulate muscle commitment. To validate this method, we used multi-photon confocal microscopy to confirm the potential of bioactives to stimulate muscle differentiation and expression of desmin. Imaging multicolor flow cytometry revealed statistically significant differences between treated and untreated groups of myogenic progenitors and we propose the utilization of this concept as an integral part of future muscle research strategies.

  15. Transcriptional networks that regulate muscle stem cell function.

    PubMed

    Punch, Vincent G; Jones, Andrew E; Rudnicki, Michael A

    2009-01-01

    Muscle stem cells comprise different populations of stem and progenitor cells found in embryonic and adult tissues. A number of signaling and transcriptional networks are responsible for specification and survival of these cell populations and regulation of their behavior during growth and regeneration. Muscle progenitor cells are mostly derived from the somites of developing embryos, while satellite cells are the progenitor cells responsible for the majority of postnatal growth and adult muscle regeneration. In resting muscle, these stem cells are quiescent, but reenter the cell cycle during their activation, whereby they undergo decisions to self-renew, proliferate, or differentiate and fuse into multinucleated myofibers to repair damaged muscle. Regulation of muscle stem cell activity is under the precise control of a number of extrinsic signaling pathways and active transcriptional networks that dictate their behavior, fate, and regenerative potential. Here, we review the networks responsible for these different aspects of muscle stem cell biology and discuss prevalent parallels between mechanisms regulating the activity of embryonic muscle progenitor cells and adult satellite cells.

  16. Lymphatic Muscle Cells in Rat Mesenteric Lymphatic Vessels of Various Ages

    PubMed Central

    Bridenbaugh, Eric A.; Nizamutdinova, Irina Tsoy; Jupiter, Daniel; Nagai, Takashi; Thangaswamy, Sangeetha; Chatterjee, Victor

    2013-01-01

    Abstract Background Recent studies on aging-associated changes in mesenteric lymph flow in situ demonstrated predominance of the severe negative chronotropic effect of aging on the contractility of aged mesenteric lymphatic vessels (MLV). At the same time, contraction amplitude of the aged vessels was only slightly diminished by aging and can be rapidly stimulated within 5–15 minutes. However, the detailed quantitative evaluation of potential aging-associated changes in muscle cells investiture in MLV has never been performed. Methods and Results In this study we, for the first time, performed detailed evaluation of muscle cells investiture in MLV in reference to the position of lymphatic valve in different zones of lymphangion within various age groups (3-mo, 9-mo and 24-mo Fischer-344 rats). Using visual and quantitative analyses of the images of MLV immunohistochemically labeled for actin, we confirmed that the zones located close upstream (pre-valve zones) and above lymphatic valves (valve zones) possess the lowest investiture of lymphatic muscle cells. Most of the high muscle cells investiture zones exist downstream to the lymphatic valve (post-valve zones). The muscle cells investiture of these zones is not affected by aging, while pre-valve and valve zones demonstrate significant aging-associated decrease in muscle cells investiture. Conclusions The low muscle cells investiture zones in lymphatic vessels consist of predominantly longitudinally oriented muscle cells which are positioned in pre-valve and valve zones and connect adjacent lymphangions. These cells may provide important functional impact on the biomechanics of the lymphatic valve gating and electrical coupling between lymphangions, while their aging-associated changes may delimit adaptive reserves of aged lymphatic vessels. PMID:23531183

  17. Isolation and Culture of Satellite Cells from Mouse Skeletal Muscle.

    PubMed

    Musarò, Antonio; Carosio, Silvia

    2017-01-01

    Skeletal muscle tissue is characterized by a population of quiescent mononucleated myoblasts, localized between the basal lamina and sarcolemma of myofibers, known as satellite cells. Satellite cells play a pivotal role in muscle homeostasis and are the major source of myogenic precursors in mammalian muscle regeneration.This chapter describes protocols for isolation and culturing satellite cells isolated from mouse skeletal muscles. The classical procedure, which will be discussed extensively in this chapter, involves the enzymatic dissociation of skeletal muscles, while the alternative method involves isolation of satellite cells from isolated myofibers in which the satellite cells remain in their in situ position underneath the myofiber basal lamina.In particular, we discuss the technical aspect of satellite cell isolation, the methods necessary to enrich the satellite cell fraction and the culture conditions that optimize proliferation and myotube formation of mouse satellite cells.

  18. The muscle satellite cell at 50: the formative years

    PubMed Central

    2011-01-01

    In February 1961, Alexander Mauro described a cell 'wedged' between the plasma membrane of the muscle fibre and the surrounding basement membrane. He postulated that it could be a dormant myoblast, poised to repair muscle when needed. In the same month, Bernard Katz also reported a cell in a similar location on muscle spindles, suggesting that it was associated with development and growth of intrafusal muscle fibres. Both Mauro and Katz used the term 'satellite cell' in relation to their discoveries. Today, the muscle satellite cell is widely accepted as the resident stem cell of skeletal muscle, supplying myoblasts for growth, homeostasis and repair. Since 2011 marks both the 50th anniversary of the discovery of the satellite cell, and the launch of Skeletal Muscle, it seems an opportune moment to summarise the seminal events in the history of research into muscle regeneration. We start with the 19th-century pioneers who showed that muscle had a regenerative capacity, through to the descriptions from the mid-20th century of the underlying cellular mechanisms. The journey of the satellite cell from electron microscope curio, to its gradual acceptance as a bona fide myoblast precursor, is then charted: work that provided the foundations for our understanding of the role of the satellite cell. Finally, the rapid progress in the age of molecular biology is briefly discussed, and some ongoing debates on satellite cell function highlighted. PMID:21849021

  19. Amino acid pools in cultured muscle cells.

    PubMed

    Low, R B; Stirewalt, W S; Rittling, S R; Woodworth, R C

    1984-01-01

    Compartmentalization of cellular amino acid pools occurs in cultures of cardiac and skeletal muscle cells, but the factors involved in this are not clear. We have further defined this problem by analyzing the intracellular free leucine and the transfer-RNA-(tRNA)-bound leucine pool in cultures of skeletal and cardiac muscle incubated with 3H-leucine in the presence and absence of serum and amino acids. Withdrawal of nitrogen substrates caused substantial changes in leucine pool relationships--in particular, a change in the degree to which intracellular free leucine and tRNA-leucine were derived from the culture medium. In separate experiments, the validity of our tRNA measurements was confirmed by measurements of the specific activity of newly synthesized ferritin after iron induction. We discuss the implications of these findings with regard to factors involved in the control of amino acid flux through the cell, as well as with regard to design of experiments using isotopic amino acids to measure rates of amino acid utilization.

  20. Movements elicited by electrical stimulation of muscles, nerves, intermediate spinal cord, and spinal roots in anesthetized and decerebrate cats.

    PubMed

    Aoyagi, Yoichiro; Mushahwar, Vivian K; Stein, Richard B; Prochazka, Arthur

    2004-03-01

    Electrical stimulation offers the possibility of restoring motor function of paralyzed limbs after spinal-cord injury or stroke, but few data are available to compare possible sites of stimulation, such as muscle, nerve, spinal roots, or spinal cord. The aim of this study was to establish some characteristics of stimulation at these sites in the anesthetized and midcollicular decerebrate cat. The hind limb was constrained to move in the sagittal plane against a spring load. Ventral-root stimulation only produced movements down and back; the direction moved systematically backward the more caudal the stimulated roots. In contrast, dorsal-root stimulation only produced movements up and forward. Thus, neither method alone could produce the full range of normal movements. Muscle, nerve, and intraspinal stimulation within the intermediate regions of the gray matter generated discrete, selective movements in a wide range of directions. Muscle stimulation required an order of magnitude more current. Single microwire electrodes located in the spinal gray matter could activate a synergistic group of muscles, and generally had graded recruitment curves, but the direction of movement occasionally changed abruptly as stimulus strength increased. Nerve stimulation produced the largest movements against the spring load (>80% of the passive range of motion) and was the most reproducible from animal to animal. However, recruitment curves with nerve stimulation were quite steep, so fine control of movement might be difficult. The muscle, nerve, and spinal cord all seem to be feasible sites to restore motor function. The pros and cons from this study may be helpful in deciding the best site for a particular application, but further tests are needed in the chronically transected spinal cord to assess the applicability of these results to human patients.

  1. After-effects of stretch on the responses of cat soleus muscle spindles to static fusimotor stimulation.

    PubMed

    Proske, U; Morgan, D L

    1985-01-01

    Mammalian muscle spindles show persistent after-effects following conditioning stretch or fusimotor stimulation. Most previous observations have been carried out on primary endings of spindles and using dynamic fusimotor stimulation. We report here observations on after-effects produced either by conditioning stretch or by static fusimotor stimulation on the responses of primary and secondary endings to a slow test stretch during which a brief burst of static fusimotor stimulation is applied. We find that the response to the test burst is large if the muscle is kept short after conditioning but it becomes depressed if the muscle is held stretched for 3 s following conditioning. We attribute these effects to the presence of stable cross-bridges between actin and myosin filaments in intrafusal fibres. We conclude that, qualitatively, after-effects using static fusimotor testing are the same as with dynamic fusimotor testing and this must be taken into account when providing an explanation for the phenomenon.

  2. Role of cyclic GMP in cells with the properties of smooth muscle cultured from the rat myometrium

    SciTech Connect

    Krall, J.F.; Morin, A.

    1986-11-01

    Cells growing in culture with previously described properties of rat uterine smooth muscle accumulated /sup 45/Ca/sup 2 +/ from the medium. Ca/sup 2 +/ uptake by these cells was stimulated by the addition to the medium of 8-bromo-cGMP but not by 8-bromo-cAMP. Ca/sup 2 +/ uptake was also stimulated by carbachol and by the nitro-vasodilator nitroprusside. Although cholinergic agonists have been shown previously to stimulate contraction but not cGMP synthesis in the rat myometrium, both carbachol and nitroprusside stimulated cGMP production by the cultured cells. These results suggested the cells had cholinergic receptor-medicated functions that reflected some neurotransmitter-sensitive properties of uterine smooth muscle in situ. When determined by a specific radioligand binding assay, subcellular fractions of the cultured cells bound muscarinic cholinergic agonists and antagonists with affinities expected of the muscarinic receptor. The cells were also sensitive to the ..beta..-adrenergic catecholamine agonist isoproterenol, which stimulated cAMP production but not Ca/sup 2 +/ uptake. Carbachol failed to inhibit isoproterenol-dependent cAMP production, which is an important property of the cholinergic receptor in uterine smooth muscle in situ. These results suggest some but not all acetylcholine-sensitive properties of uterine smooth muscle may be retained in cell culture.

  3. Brain and muscle Arnt-like 1 promotes skeletal muscle regeneration through satellite cell expansion

    SciTech Connect

    Chatterjee, Somik; Yin, Hongshan; Nam, Deokhwa; Li, Yong; Ma, Ke

    2015-02-01

    Circadian clock is an evolutionarily conserved timing mechanism governing diverse biological processes and the skeletal muscle possesses intrinsic functional clocks. Interestingly, although the essential clock transcription activator, Brain and muscle Arnt-like 1 (Bmal1), participates in maintenance of muscle mass, little is known regarding its role in muscle growth and repair. In this report, we investigate the in vivo function of Bmal1 in skeletal muscle regeneration using two muscle injury models. Bmal1 is highly up-regulated by cardiotoxin injury, and its genetic ablation significantly impairs regeneration with markedly suppressed new myofiber formation and attenuated myogenic induction. A similarly defective regenerative response is observed in Bmal1-null mice as compared to wild-type controls upon freeze injury. Lack of satellite cell expansion accounts for the regeneration defect, as Bmal1{sup −/−} mice display significantly lower satellite cell number with nearly abolished induction of the satellite cell marker, Pax7. Furthermore, satellite cell-derived primary myoblasts devoid of Bmal1 display reduced growth and proliferation ex vivo. Collectively, our results demonstrate, for the first time, that Bmal1 is an integral component of the pro-myogenic response that is required for muscle repair. This mechanism may underlie its role in preserving adult muscle mass and could be targeted therapeutically to prevent muscle-wasting diseases. - Highlights: • Bmal1 is highly inducible by muscle injury and myogenic stimuli. • Genetic ablation of Bmal1 significantly impairs muscle regeneration. • Bmal1 promotes satellite cell expansion during muscle regeneration. • Bmal1-deficient primary myoblasts display attenuated growth and proliferation.

  4. Brain-controlled muscle stimulation for the restoration of motor function

    PubMed Central

    Ethier, Christian; Miller, Lee E

    2014-01-01

    Loss of the ability to move, as a consequence of spinal cord injury or neuromuscular disorder, has devastating consequences for the paralyzed individual, and great economic consequences for society. Functional Electrical Stimulation (FES) offers one means to restore some mobility to these individuals, improving not only their autonomy, but potentially their general health and well-being as well. FES uses electrical stimulation to cause the paralyzed muscles to contract. Existing clinical systems require the stimulation to be preprogrammed, with the patient typically using residual voluntary movement of another body part to trigger and control the patterned stimulation. The rapid development of neural interfacing in the past decade offers the promise of dramatically improved control for these patients, potentially allowing continuous control of FES through signals recorded from motor cortex, as the patient attempts to control the paralyzed body part. While application of these ‘Brain Machine Interfaces’ (BMIs) has undergone dramatic development for control of computer cursors and even robotic limbs, their use as an interface for FES has been much more limited. In this review, we consider both FES and BMI technologies and discuss the prospect for combining the two to provide important new options for paralyzed individuals. PMID:25447224

  5. Brain-controlled muscle stimulation for the restoration of motor function.

    PubMed

    Ethier, Christian; Miller, Lee E

    2015-11-01

    Loss of the ability to move, as a consequence of spinal cord injury or neuromuscular disorder, has devastating consequences for the paralyzed individual, and great economic consequences for society. Functional electrical stimulation (FES) offers one means to restore some mobility to these individuals, improving not only their autonomy, but potentially their general health and well-being as well. FES uses electrical stimulation to cause the paralyzed muscles to contract. Existing clinical systems require the stimulation to be preprogrammed, with the patient typically using residual voluntary movement of another body part to trigger and control the patterned stimulation. The rapid development of neural interfacing in the past decade offers the promise of dramatically improved control for these patients, potentially allowing continuous control of FES through signals recorded from motor cortex, as the patient attempts to control the paralyzed body part. While application of these 'brain-machine interfaces' (BMIs) has undergone dramatic development for control of computer cursors and even robotic limbs, their use as an interface for FES has been much more limited. In this review, we consider both FES and BMI technologies and discuss the prospect for combining the two to provide important new options for paralyzed individuals.

  6. Dissemination of Walker 256 carcinoma cells to rat skeletal muscle

    SciTech Connect

    Ueoka, H.; Hayashi, K.; Namba, T.; Grob, D.

    1986-03-05

    After injection of 10/sup 6/ Walker 256 carcinoma cells labelled with /sup 125/I-5-iodo-2'-deoxyuridine into the tail vein, peak concentration in skeletal muscle was 46 cells/g at 60 minutes, which was lower than 169202, 1665, 555, 198 and 133 cells/g, respectively, at 30 or 60 minutes in lung, liver, spleen, kidney and heart. Because skeletal muscle constitutes 37.4% of body weight, the total number of tumor cells was 2323 cells, which was much greater than in spleen, kidney and heart with 238, 271, and 85 cells, respectively, and only less than in lung and liver, at 222857 and 11700 cells, respectively. The total number in skeletal muscle became greater than in liver at 4 hours and than in lung at 24 hours. Ten minutes after injection of 7.5 x 10/sup 6/ Walker 256 carcinoma cells into the abdominal aorta of rats, a mean of 31 colony-forming cells were recovered from the gastrocnemius, while 10