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Lunde PK, Manfra O, Støle TP, Lunde M, Martinsen M, Carlson CR, Louch WE. Polyarginine Cell-Penetrating Peptides Bind and Inhibit SERCA2. Cells 2023; 12:2358. [PMID: 37830576 PMCID: PMC10571751 DOI: 10.3390/cells12192358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023] Open
Abstract
Cell-penetrating peptides (CPPs) are short peptide sequences that have the ability to cross the cell membrane and deliver cargo. Although it is critical that CPPs accomplish this task with minimal off-target effects, such actions have in many cases not been robustly screened. We presently investigated whether the commonly used CPPs TAT and the polyarginines Arg9 and Arg11 exert off-target effects on cellular Ca2+ homeostasis. In experiments employing myocytes and homogenates from the cardiac left ventricle or soleus muscle, we observed marked inhibition of Ca2+ recycling into the sarcoplasmic reticulum (SR) following incubation with polyarginine CPPs. In both tissues, the rate of SR Ca2+ leak remained unchanged, indicating that protracted Ca2+ removal from the cytosol stemmed from inhibition of the SR Ca2+ ATPase 2 (SERCA2). No such inhibition occurred following treatment with TAT, or in preparations from the SERCA1-expressing extensor digitorum longus muscle. Experiments in HEK cells overexpressing individual SERCA isoforms confirmed that polyarginine incubation specifically inhibited the activity of SERCA2a and 2b, but not SERCA1 or 3. The attenuation of SERCA2 activity was not dependent on the presence of phospholamban, and ELISA-based analyses rather revealed direct interaction between the polyarginines and the actuator domain of the protein. Surface plasmon resonance experiments confirmed strong binding within this region of SERCA2, and slow dissociation between the two species. Based on these observations, we urge caution when employing polyarginine CPPs. Indeed, as SERCA2 is expressed in diverse cell types, the wide-ranging consequences of SERCA2 binding and inhibition should be anticipated in both experimental and therapeutic settings.
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Affiliation(s)
| | | | | | | | | | - Cathrine Rein Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway; (P.K.L.); (O.M.); (T.P.S.); (M.L.); (M.M.); (W.E.L.)
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Gallagher H, Hendrickse PW, Pereira MG, Bowen TS. Skeletal muscle atrophy, regeneration, and dysfunction in heart failure: Impact of exercise training. JOURNAL OF SPORT AND HEALTH SCIENCE 2023; 12:557-567. [PMID: 37040849 PMCID: PMC10466197 DOI: 10.1016/j.jshs.2023.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/30/2022] [Accepted: 02/20/2023] [Indexed: 05/31/2023]
Abstract
This review highlights some established and some more contemporary mechanisms responsible for heart failure (HF)-induced skeletal muscle wasting and weakness. We first describe the effects of HF on the relationship between protein synthesis and degradation rates, which determine muscle mass, the involvement of the satellite cells for continual muscle regeneration, and changes in myofiber calcium homeostasis linked to contractile dysfunction. We then highlight key mechanistic effects of both aerobic and resistance exercise training on skeletal muscle in HF and outline its application as a beneficial treatment. Overall, HF causes multiple impairments related to autophagy, anabolic-catabolic signaling, satellite cell proliferation, and calcium homeostasis, which together promote fiber atrophy, contractile dysfunction, and impaired regeneration. Although both wasting and weakness are partly rescued by aerobic and resistance exercise training in HF, the effects of satellite cell dynamics remain poorly explored.
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Affiliation(s)
- Harrison Gallagher
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Paul W Hendrickse
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Marcelo G Pereira
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - T Scott Bowen
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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Song T, Manoharan P, Millay DP, Koch SE, Rubinstein J, Heiny JA, Sadayappan S. Dilated cardiomyopathy-mediated heart failure induces a unique skeletal muscle myopathy with inflammation. Skelet Muscle 2019; 9:4. [PMID: 30678732 PMCID: PMC6345027 DOI: 10.1186/s13395-019-0189-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/10/2019] [Indexed: 02/02/2023] Open
Abstract
Background Skeletal muscle myopathy and exercise intolerance are diagnostic hallmarks of heart failure (HF). However, the molecular adaptations of skeletal muscles during dilated cardiomyopathy (DCM)-mediated HF are not completely understood. Methods Skeletal muscle structure and function were compared in wild-type (WT) and cardiac myosin binding protein-C null mice (t/t), which develop DCM-induced HF. Cardiac function was examined by echocardiography. Exercise tolerance was measured using a graded maximum treadmill running test. Hindlimb muscle function was assessed in vivo from measurements of plantar flexor strength. Inflammatory status was evaluated from the expression of inflammatory markers and the presence of specific immune cell types in gastrocnemius muscles. Muscle regenerative capacityat days 3, 7, and 14 after eccentric contraction-induced injury was determined from the number of phenotypically new and adult fibers in the gastrocnemius, and functional recovery of plantar flexion torque. Results t/t mice developed DCM-induced HF in association with profound exercise intolerance, consistent with previous reports. Compared to WT, t/t mouse hearts show significant hypertrophy of the atria and ventricles and reduced fractional shortening, both systolic and diastolic. In parallel, the skeletal muscles of t/t mice exhibit weakness and myopathy. Compared to WT, plantar flexor muscles of t/t null mice produce less peak isometric plantar torque (Po), develop torque more slowly (+ dF/dt), and relax more slowly (− dF/dt, longer half-relaxation times,1/2RT). Gastrocnemius muscles of t/t mice have a greater number of fibers with smaller diameters and central nuclei. Oxidative fibers, both type I and type IIa, show significantly smaller cross-sectional areas and more central nuclei. These fiber phenotypes suggest ongoing repair and regeneration under homeostatic conditions. In addition, the ability of muscles to recover and regenerate after acute injury is impaired in t/t mice. Conclusions Our studies concluded that DCM-induced HF induces a unique skeletal myopathy characterized by decreased muscle strength, atrophy of oxidative fiber types, ongoing inflammation and damage under homeostasis, and impaired regeneration after acute muscle injury. Furthermore, this unique myopathy in DCM-induced HF likely contributes to and exacerbates exercise intolerance. Therefore, efforts to develop therapeutic interventions to treat skeletal myopathy during DCM-induced HF should be considered. Electronic supplementary material The online version of this article (10.1186/s13395-019-0189-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Taejeong Song
- Heart Lung Vascular Institute, Division of Cardiology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Palanikumar Manoharan
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, 240 Albert Sabin Way, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Sheryl E Koch
- Heart Lung Vascular Institute, Division of Cardiology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Jack Rubinstein
- Heart Lung Vascular Institute, Division of Cardiology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Judith A Heiny
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Sakthivel Sadayappan
- Heart Lung Vascular Institute, Division of Cardiology, University of Cincinnati, Cincinnati, OH, 45267, USA. .,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA.
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Hortemo KH, Lunde PK, Anonsen JH, Kvaløy H, Munkvik M, Rehn TA, Sjaastad I, Lunde IG, Aronsen JM, Sejersted OM. Exercise training increases protein O-GlcNAcylation in rat skeletal muscle. Physiol Rep 2016; 4:4/18/e12896. [PMID: 27664189 PMCID: PMC5037911 DOI: 10.14814/phy2.12896] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 07/19/2016] [Indexed: 11/24/2022] Open
Abstract
Protein O-GlcNAcylation has emerged as an important intracellular signaling system with both physiological and pathophysiological functions, but the role of protein O-GlcNAcylation in skeletal muscle remains elusive. In this study, we tested the hypothesis that protein O-GlcNAcylation is a dynamic signaling system in skeletal muscle in exercise and disease. Immunoblotting showed different protein O-GlcNAcylation pattern in the prototypical slow twitch soleus muscle compared to fast twitch EDL from rats, with greater O-GlcNAcylation level in soleus associated with higher expression of the modulating enzymes O-GlcNAc transferase (OGT), O-GlcNAcase (OGA), and glutamine fructose-6-phosphate amidotransferase isoforms 1 and 2 (GFAT1, GFAT2). Six weeks of exercise training by treadmill running, but not an acute exercise bout, increased protein O-GlcNAcylation in rat soleus and EDL There was a striking increase in O-GlcNAcylation of cytoplasmic proteins ~50 kDa in size that judged from mass spectrometry analysis could represent O-GlcNAcylation of one or more key metabolic enzymes. This suggests that cytoplasmic O-GlcNAc signaling is part of the training response. In contrast to exercise training, postinfarction heart failure (HF) in rats and humans did not affect skeletal muscle O-GlcNAcylation level, indicating that aberrant O-GlcNAcylation cannot explain the skeletal muscle dysfunction in HF Human skeletal muscle displayed extensive protein O-GlcNAcylation that by large mirrored the fiber-type-related O-GlcNAcylation pattern in rats, suggesting O-GlcNAcylation as an important signaling system also in human skeletal muscle.
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Affiliation(s)
- Kristin Halvorsen Hortemo
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Per Kristian Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | | | - Heidi Kvaløy
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Morten Munkvik
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Tommy Aune Rehn
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ida Gjervold Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Bjørknes College, Oslo, Norway
| | - Ole M Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
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Muscle fatigue resistance in the rat hindlimbin vivofrom low dietary intakes of tuna fish oil that selectively increase phospholipidn-3 docosahexaenoic acid according to muscle fibre type. Br J Nutr 2015; 114:873-84. [DOI: 10.1017/s0007114515002512] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AbstractDietary fish oil (FO) modulates muscle O2consumption and contractile function, predictive of effects on muscle fatigue. High doses unattainable through human diet and muscle stimulation parameters used engender uncertainty in their physiological relevance. We tested the hypothesis that nutritionally relevant FO doses can modulate membrane fatty acid composition and muscle fatigue. Male Sprague–Dawley rats were randomised to control (10 % olive oil (OO) by weight) or low or moderate FO diet (LowFO and ModFO) (HiDHA tuna fish oil) for 15 weeks (LowFO: 0·3 % FO, 9·7 % OO, 0·25 % energy as EPA+DHA; ModFO: 1·25 % FO, 8·75 % OO, 1·0 % energy as EPA+DHA). Hindlimb muscle function was assessed under anaesthesiain vivousing repetitive 5 s burst sciatic nerve stimulation (0·05 ms, 7–12 V, 5 Hz, 10 s duty cycle, 300 s). There were no dietary differences in maximum developed muscle force. Repetitive peak developed force fell to 50 % within 62 (sem10) s in controls and took longer to decline in FO-fed rats (LowFO 110 (sem15) s; ModFO 117 (sem14) s) (P<0·05). Force within bursts was better sustained with FO and maximum rates of force development and relaxation declined more slowly. The FO-fed rats incorporated higher muscle phospholipid DHA-relative percentages than controls (P<0·001). Incorporation of DHA was greater in the fast-twitch gastrocnemius (Control 9·3 (sem0·8) %, LowFO 19·9 (sem0·4), ModFO 24·3 (sem1·0)) than in the slow-twitch soleus muscle (Control 5·1 (sem0·2), LowFO 14·3 (sem0·7), ModFO 18·0 (sem1·4)) (P<0·001), which was comparable with the myocardium, in line with muscle fibre characteristics. The LowFO and ModFO diets, emulating human dietary and therapeutic supplement intake, respectively, both elicited muscle membrane DHA enrichment and fatigue resistance, providing a foundation for translating these physiological effects to humans.
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Rehn TA, Munkvik M, Lunde PK, Sjaastad I, Sejersted OM. Intrinsic skeletal muscle alterations in chronic heart failure patients: a disease-specific myopathy or a result of deconditioning? Heart Fail Rev 2013; 17:421-36. [PMID: 21996779 DOI: 10.1007/s10741-011-9289-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Chronic heart failure (CHF) patients frequently experience impaired exercise tolerance due to skeletal muscle fatigue. Studies suggest that this in part is due to intrinsic alterations in skeletal muscle of CHF patients, often interpreted as a disease-specific myopathy. Knowledge about the mechanisms underlying these skeletal muscle alterations is of importance for the pathophysiological understanding of CHF, therapeutic approach and rehabilitation strategies. We here critically review the evidence for skeletal muscle alterations in CHF, the underlying mechanisms of such alterations and how skeletal muscle responds to training in this patient group. Skeletal muscle characteristics in CHF patients are very similar to what is reported in response to chronic obstructive pulmonary disease (COPD), detraining and deconditioning. Furthermore, skeletal muscle alterations observed in CHF patients are reversible by training, and skeletal muscle of CHF patients seems to be at least as trainable as that of matched controls. We argue that deconditioning is a major contributor to the skeletal muscle dysfunction in CHF patients and that further research is needed to determine whether, and to what extent, the intrinsic skeletal muscle alterations in CHF represent an integral part of the pathophysiology in this disease.
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Affiliation(s)
- T A Rehn
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevaal, Oslo, Norway.
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Copp SW, Hirai DM, Ferguson SK, Holdsworth CT, Musch TI, Poole DC. Effects of chronic heart failure on neuronal nitric oxide synthase-mediated control of microvascular O2 pressure in contracting rat skeletal muscle. J Physiol 2012; 590:3585-96. [PMID: 22687613 DOI: 10.1113/jphysiol.2012.235929] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Chronic heart failure (CHF) impairs nitric oxide (NO)-mediated regulation of the skeletal muscle microvascular O(2) delivery/V(O(2)) ratio (which sets the microvascular O(2) pressure, PO(2)mv). Given the pervasiveness of endothelial dysfunction in CHF, this NO-mediated dysregulation is attributed generally to eNOS. It is unknown whether nNOS-mediated PO(2)mv regulation is altered in CHF. We tested the hypothesis that CHF impairs nNOS-mediated PO(2)mv control. In healthy and CHF (left ventricular end diastolic pressure (LVEDP): 6 ± 1 versus 14 ± 1 mmHg, respectively, P < 0.05) rats spinotrapezius muscle blood flow (radiolabelled microspheres), PO(2)mv (phosphorescence quenching), and V(O(2)) (Fick calculation) were measured before and after 0.56 mg kg(-1)i.a. of the selective nNOS inhibitor S-methyl-l-thiocitrulline (SMTC). In healthy rats, SMTC increased baseline PO(2)mv ( CONTROL 29.7 ± 1.4, SMTC: 34.4 ± 1.9 mmHg, P < 0.05) by reducing V(O(2)) (↓20%) without any effect on blood flow and speeded the mean response time (MRT, time to reach 63% of the overall kinetics response, CONTROL 24.2 ± 2.0, SMTC: 18.5 ± 1.3 s, P < 0.05). In CHF rats, SMTC did not alter baseline PO(2)mv ( CONTROL 25.7 ± 1.6, SMTC: 28.6 ± 2.1 mmHg, P > 0.05), V(O(2)) at rest, or the MRT (CONTROL: 22.8 ± 2.6, SMTC: 21.3 ± 3.0 s, P > 0.05). During the contracting steady-state, SMTC reduced blood flow (↓15%) and V(O(2)) (↓15%) in healthy rats such that PO(2)mv was unaltered ( CONTROL 19.8 ± 1.7, SMTC: 20.7 ± 1.8 mmHg, P > 0.05). In marked contrast, in CHF rats SMTC did not change contracting steady-state blood flow, V(O(2)), or PO(2)mv ( CONTROL 17.0 ± 1.4, SMTC: 17.7 ± 1.8 mmHg, P > 0.05). nNOS-mediated control of skeletal muscle microvascular function is compromised in CHF versus healthy rats. Treatments designed to ameliorate microvascular dysfunction in CHF may benefit by targeting improvements in nNOS function.
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Affiliation(s)
- Steven W Copp
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506-5802, USA
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Munkvik M, Lunde PK, Aronsen JM, Birkeland JAK, Sjaastad I, Sejersted OM. Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure. PLoS One 2011; 6:e22695. [PMID: 21799933 PMCID: PMC3143175 DOI: 10.1371/journal.pone.0022695] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 07/04/2011] [Indexed: 01/08/2023] Open
Abstract
During isometric contractions, slow twitch soleus muscles (SOL) from rats with chronic heart failure (chf) are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic) contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf) if left ventricle end diastolic pressure was >15 mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off) at 30 Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (F(max)) and the concentrations of ATP and CrP were not different in the two groups. During stimulation, F(max) and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue.
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Affiliation(s)
- Morten Munkvik
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Per Kristian Lunde
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jon Arne Kro Birkeland
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
- Department of Cardiology, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Ole M. Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
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Hinkle RT, Lefever FR, Dolan ET, Reichart DL, Zwolshen JM, Oneill TP, Maloney KG, Mattson JP, Ferreira LF, Musch TI, Poole DC, Isfort RJ. Treatment with a corticotrophin releasing factor 2 receptor agonist modulates skeletal muscle mass and force production in aged and chronically ill animals. BMC Musculoskelet Disord 2011; 12:15. [PMID: 21235761 PMCID: PMC3025927 DOI: 10.1186/1471-2474-12-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 01/14/2011] [Indexed: 11/17/2022] Open
Abstract
Background Muscle weakness is associated with a variety of chronic disorders such as emphysema (EMP) and congestive heart failure (CHF) as well as aging. Therapies to treat muscle weakness associated with chronic disease or aging are lacking. Corticotrophin releasing factor 2 receptor (CRF2R) agonists have been shown to maintain skeletal muscle mass and force production in a variety of acute conditions that lead to skeletal muscle wasting. Hypothesis We hypothesize that treating animals with a CRF2R agonist will maintain skeletal muscle mass and force production in animals with chronic disease and in aged animals. Methods We utilized animal models of aging, CHF and EMP to evaluate the potential of CRF2R agonist treatment to maintain skeletal muscle mass and force production in aged animals and animals with CHF and EMP. Results In aged rats, we demonstrate that treatment with a CRF2R agonist for up to 3 months results in greater extensor digitorum longus (EDL) force production, EDL mass, soleus mass and soleus force production compared to age matched untreated animals. In the hamster EMP model, we demonstrate that treatment with a CRF2R agonist for up to 5 months results in greater EDL force production in EMP hamsters when compared to vehicle treated EMP hamsters and greater EDL mass and force in normal hamsters when compared to vehicle treated normal hamsters. In the rat CHF model, we demonstrate that treatment with a CRF2R agonist for up to 3 months results in greater EDL and soleus muscle mass and force production in CHF rats and normal rats when compared to the corresponding vehicle treated animals. Conclusions These data demonstrate that the underlying physiological conditions associated with chronic diseases such as CHF and emphysema in addition to aging do not reduce the potential of CRF2R agonists to maintain skeletal muscle mass and force production.
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Bueno CR, Ferreira JCB, Pereira MG, Bacurau AVN, Brum PC. Aerobic exercise training improves skeletal muscle function and Ca2+ handling-related protein expression in sympathetic hyperactivity-induced heart failure. J Appl Physiol (1985) 2010; 109:702-9. [DOI: 10.1152/japplphysiol.00281.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The cellular mechanisms of positive effects associated with aerobic exercise training on overall intrinsic skeletal muscle changes in heart failure (HF) remain unclear. We investigated potential Ca2+ abnormalities in skeletal muscles comprising different fiber compositions and investigated whether aerobic exercise training would improve muscle function in a genetic model of sympathetic hyperactivity-induced HF. A cohort of male 5-mo-old wild-type (WT) and congenic α2A/α2C adrenoceptor knockout (ARKO) mice in a C57BL/6J genetic background were randomly assigned into untrained and trained groups. Exercise training consisted of a 8-wk running session of 60 min, 5 days/wk (from 5 to 7 mo of age). After completion of the exercise training protocol, exercise tolerance was determined by graded treadmill exercise test, muscle function test by Rotarod, ambulation and resistance to inclination tests, cardiac function by echocardiography, and Ca2+ handling-related protein expression by Western blot. α2A/α2CARKO mice displayed decreased ventricular function, exercise intolerance, and muscle weakness paralleled by decreased expression of sarcoplasmic Ca2+ release-related proteins [α1-, α2-, and β1-subunits of dihydropyridine receptor (DHPR) and ryanodine receptor (RyR)] and Ca2+ reuptake-related proteins [sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)1/2 and Na+/Ca2+ exchanger (NCX)] in soleus and plantaris. Aerobic exercise training significantly improved exercise tolerance and muscle function and reestablished the expression of proteins involved in sarcoplasmic Ca2+ handling toward WT levels. We provide evidence that Ca2+ handling-related protein expression is decreased in this HF model and that exercise training improves skeletal muscle function associated with changes in the net balance of skeletal muscle Ca2+ handling proteins.
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Affiliation(s)
- C. R. Bueno
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - J. C. B. Ferreira
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - M. G. Pereira
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - A. V. N. Bacurau
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - P. C. Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
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Munkvik M, Lunde PK, Sejersted OM. Causes of fatigue in slow-twitch rat skeletal muscle during dynamic activity. Am J Physiol Regul Integr Comp Physiol 2009; 297:R900-10. [PMID: 19625691 DOI: 10.1152/ajpregu.91043.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle fatigue is most often studied in vitro at room temperature and is classically defined as a decline in maximum force production or power output, exclusively linked to repeated isometric contractions. However, most muscles shorten during normal use, and we propose that both the functional correlate of fatigue, as well as the fatigue mechanism, will be different during dynamic contractions compared with static contractions. Under isoflurane anesthesia, fatigue was induced in rat soleus muscles in situ by isotonic shortening contractions at 37 degrees C. Muscles were stimulated repeatedly for 1 s at 30 Hz every 2 s for a total of 15 min. The muscles were allowed to shorten isotonically against a load corresponding to one-third of maximal isometric force. Maximal unloaded shortening velocity (V(0)), maximum force production (F(max)), and isometric relaxation rate (-dF/dt) was reduced after 100 s but returned to almost initial values at the end of the stimulation protocol. Likewise, ATP and creatine phosphate (CrP) were reduced after 100 s, but the level of CrP was partially restored to initial values after 15 min. The rate of isometric force development, the velocity of shortening, and isotonic shortening were also reduced at 100 s, but in striking contrast, did not recover during the remainder of the stimulation protocol. The regulatory myosin light chain (MLC2s) was dephosphorylated after 100 s and did not recover. Although metabolic changes may account for the changes of F(max), -dF/dt, and V(0), dephosphorylation of MLC2s may be involved in the fatigue seen as sustained slower contraction velocities and decreased muscle shortening.
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Affiliation(s)
- Morten Munkvik
- Institute for Experimental Medical Research, Oslo Univ. Hospital, Ullevål, Kirkeveien 166, N-0407 Oslo, Norway.
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12
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Rehn TA, Borge BA, Lunde PK, Munkvik M, Sneve ML, Grøndahl F, Aronsen JM, Sjaastad I, Prydz K, Kolset SO, Wiig H, Sejersted OM, Iversen PO. Temporary fatigue and altered extracellular matrix in skeletal muscle during progression of heart failure in rats. Am J Physiol Regul Integr Comp Physiol 2009; 297:R26-33. [PMID: 19339678 DOI: 10.1152/ajpregu.90617.2008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Patients with congestive heart failure (CHF) experience increased skeletal muscle fatigue. The mechanism underlying this phenomenon is unknown, but a deranged extracellular matrix (ECM) might be a contributing factor. Hence, we examined ECM components and regulators in a rat postinfarction model of CHF. At various time points during a 3.5 mo-period after induction of CHF in rats by left coronary artery ligation, blood, interstitial fluid (IF), and muscles were sampled. Isoflurane anesthesia was employed during all surgical procedures. IF was extracted by wicks inserted intermuscularly in a hind limb. We measured cytokines in plasma and IF, whereas matrix metalloproteinase (MMP) activity and collagen content, as well as the level of glycosaminoglycans and hyaluronan were determined in hind limb muscle. In vivo fatigue protocols of the soleus muscle were performed at 42 and 112 days after induction of heart failure. We found that the MMP activity and collagen content in the skeletal muscles increased significantly at 42 days after induction of CHF, and these changes were time related to increased skeletal muscle fatigability. These parameters returned to sham levels at 112 days. VEGF in IF was significantly lower in CHF compared with sham-operated rats at 3 and 10 days, but no difference was observed at 112 days. We conclude that temporary alterations in the ECM, possibly triggered by VEGF, are related to a transient development of skeletal muscle fatigue in CHF.
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Affiliation(s)
- Tommy A Rehn
- Institute for Experimental Medical Research, Oslo Univ. Hospital-Ullevaal, N-0407 Oslo, Norway.
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13
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Bellinger AM, Mongillo M, Marks AR. Stressed out: the skeletal muscle ryanodine receptor as a target of stress. J Clin Invest 2008; 118:445-53. [PMID: 18246195 DOI: 10.1172/jci34006] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Over the past century, understanding the mechanisms underlying muscle fatigue and weakness has been the focus of much investigation. However, the dominant theory in the field, that lactic acidosis causes muscle fatigue, is unlikely to tell the whole story. Recently, dysregulation of sarcoplasmic reticulum (SR) Ca(2+) release has been associated with impaired muscle function induced by a wide range of stressors, from dystrophy to heart failure to muscle fatigue. Here, we address current understandings of the altered regulation of SR Ca(2+) release during chronic stress, focusing on the role of the SR Ca(2+) release channel known as the type 1 ryanodine receptor.
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Affiliation(s)
- Andrew M Bellinger
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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14
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McLean L, Young IS, Doherty MK, Robertson DHL, Cossins AR, Gracey AY, Beynon RJ, Whitfield PD. Global cooling: cold acclimation and the expression of soluble proteins in carp skeletal muscle. Proteomics 2007; 7:2667-81. [PMID: 17623276 DOI: 10.1002/pmic.200601004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The common carp (Cyprinus carpio) has a well-developed capacity to modify muscle properties in response to changes in temperature. Understanding the mechanisms underpinning this phenotypic response at the protein level may provide fundamental insights into the molecular basis of adaptive processes in skeletal muscle. In this study, common carp were subjected to a cooling regimen and soluble extracts of muscle homogenates were separated by 1-D SDS-PAGE and 2-DE. Proteins were identified using MALDI-TOF-MS and de novo peptide sequencing using LC-MS/MS. The 2-D gel was populated with numerous protein spots that were fragments of all three muscle isoforms (M1, M2 and M3) of carp creatine kinase (CK). The accumulation of the CK fragments was enhanced when the carp were cooled to 10 degrees C. The protein changes observed in the skeletal muscle of carp subjected to cold acclimation were compared to changes described in a previous transcript analysis study. Genes encoding CK isoforms were downregulated and the genes encoding key proteins of the ubiquitin-proteasome pathway were upregulated. These findings are consistent with a specific cold-induced enhancement of proteolysis of CK.
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MESH Headings
- Acclimatization/physiology
- Animals
- Carps/genetics
- Carps/physiology
- Chromatography, Liquid
- Cold Temperature
- Creatine Kinase/genetics
- Creatine Kinase/isolation & purification
- Creatine Kinase/metabolism
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation, Enzymologic
- Isoenzymes
- Models, Molecular
- Muscle, Skeletal/chemistry
- Muscle, Skeletal/enzymology
- Peptide Mapping
- Proteins/genetics
- Proteins/metabolism
- Sequence Analysis, Protein
- Solubility
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Trypsin/pharmacology
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Affiliation(s)
- Lynn McLean
- Proteomics and Functional Genomics Research Group, Faculty of Veterinary Science, University of Liverpool, Liverpool, UK
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15
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Szigeti GP, Almássy J, Sztretye M, Dienes B, Szabó L, Szentesi P, Vassort G, Sárközi S, Csernoch L, Jóna I. Alterations in the calcium homeostasis of skeletal muscle from postmyocardial infarcted rats. Pflugers Arch 2007; 455:541-53. [PMID: 17558517 DOI: 10.1007/s00424-007-0298-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 04/25/2007] [Accepted: 05/21/2007] [Indexed: 11/29/2022]
Abstract
In chronic heart failure, skeletal muscles develop a weakness that is not associated to an impaired circulatory function but rather to alterations in the skeletal muscle fibers themselves. To understand these changes, the steps in excitation-contraction coupling of rats that underwent a left anterior coronary artery occlusion were studied. About 24 weeks after the myocardial infarction, neither the total amount nor the voltage dependence of intramembrane charge were altered. In contrast, calcium release from the sarcoplasmic reticulum was considerably suppressed, and its voltage dependence shifted toward more positive voltages. Elementary calcium-release events showed altered morphology as the relative proportion of embers increased. Calcium sparks were smaller in amplitude and had larger time-to-peak values. Isolated ryanodine receptors (RyR) displayed an unusual rectification with increased single-channel conductance at positive (cis vs trans) voltages. In addition, the bell-shaped calcium dependence of channel activity was broader, with a slight shift of activation to lower and a larger shift in inactivation to higher calcium concentrations. These data indicate that the number of channels that open during a calcium-release event is decreased and that RyR function is altered; thus, calcium-release is suppressed after a myocardial infarction. These observations give an explanation for the impaired skeletal muscle function in these animals.
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Affiliation(s)
- Gyula Péter Szigeti
- Department of Physiology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
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16
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Lunde PK, Sejersted OM, Thorud HMS, Tønnessen T, Henriksen UL, Christensen G, Westerblad H, Bruton J. Effects of Congestive Heart Failure on Ca
2+
Handling in Skeletal Muscle During Fatigue. Circ Res 2006; 98:1514-9. [PMID: 16690878 DOI: 10.1161/01.res.0000226529.66545.e5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Skeletal muscle weakness and decreased exercise capacity are major symptoms reported by patients with congestive heart failure (CHF). Intriguingly, these skeletal muscle symptoms do not correlate with the decreased heart function. This suggests that CHF leads to maladaptive changes in skeletal muscles, and as reported most markedly in slow-twitch muscles. We used rats at 6 weeks after infarction to measure expression of key proteins involved in SR Ca
2+
release and uptake in slow-twitch soleus muscles. We also measured force and myoplasmic free [Ca
2+
] ([Ca
2+
]
i
) in intact single fibers of soleus muscles. CHF rats showed clear signs of severe cardiac dysfunction with marked increases in heart weight and left ventricular end-diastolic pressure compared with sham operated rats (Sham). There were small, but significant, changes in the content of proteins involved in cellular Ca
2+
handling in CHF muscles: slight increases in SR Ca
2+
release channels (ie, the ryanodine receptors) and in SR Ca
2+
-ATPase. Tetanic force and [Ca
2+
]
i
were not significantly different between CHF and Sham soleus fibers under resting conditions. However, during the stimulation period there was a decrease in tetanic force without changes in [Ca
2+
]
i
in CHF fibers that was not observed in Sham fibers. The fatigue-induced changes recovered rapidly. We conclude that CHF soleus fibers fatigue more rapidly than Sham fibers because of a reversible fatigue-induced decrease in myofibrillar function.
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Affiliation(s)
- Per Kristian Lunde
- Institute for Experimental Medical Research, Ullevål University Hospital, N-0407 Oslo, Norway.
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17
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Rush JWE, Green HJ, Maclean DA, Code LM. Oxidative stress and nitric oxide synthase in skeletal muscles of rats with post-infarction, compensated chronic heart failure. ACTA ACUST UNITED AC 2005; 185:211-8. [PMID: 16218926 DOI: 10.1111/j.1365-201x.2005.01479.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Involvement of oxidative stress and nitric oxide synthase (NOS) isoforms in skeletal muscle cellular adaptations to chronic heart failure (CHF) is controversial, and possible muscle fibre-type heterogeneity in the oxidative stress and NOS responses to CHF have not been examined. Consequently, we hypothesized that the changes in determinants of elevated oxidative and nitrosylative stress associated with CHF would occur in skeletal muscle and would be similar in predominantly type I slow twitch muscle (soleus) and type II fast twitch muscle (plantaris) of rats. METHODS The purpose of this study was to measure NOS isoforms (endothelial, inducible and neuronal NOS) and antioxidant enzymes (SOD-1, SOD-2, catalase) by protein immunoblot as well as markers of oxidative stress by biochemical assays in soleus and plantaris muscle sections of the rat hind limb. This was performed for control and post-infarction, compensated CHF rats. RESULTS Twelve weeks after coronary artery ligation-induced moderate CHF, soleus exhibited decreased SOD-1, SOD-2 and eNOS, but increased iNOS and nNOS isoforms assessed by immunoblot. This was associated with elevated lipid and DNA oxidative damage assessed by biochemical assays. In contrast, plantaris muscle exhibited no changes in antioxidant enzymes or NOS isoforms, and had lower lipid and DNA oxidative damage. CONCLUSION These observations suggest a heretofore unreported muscle fibre-type-specific response of oxidative stress and NOS isoforms to CHF is of importance in understanding the cellular mechanisms of skeletal muscle dysfunction in CHF.
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MESH Headings
- Adaptation, Physiological
- Animals
- DNA Damage
- Glutathione/blood
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Failure/physiopathology
- Immunoblotting
- Lipid Peroxidation
- Male
- Muscle Fibers, Fast-Twitch/enzymology
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Slow-Twitch/enzymology
- Muscle Fibers, Slow-Twitch/pathology
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Myocardial Infarction/enzymology
- Myocardial Infarction/pathology
- Myocardial Infarction/physiopathology
- Nitric Oxide Synthase/analysis
- Oxidative Stress
- Peptidyl-Dipeptidase A/analysis
- Peptidyl-Dipeptidase A/metabolism
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- J W E Rush
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
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18
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Thorud HMS, Verburg E, Lunde PK, Strømme TA, Sjaastad I, Sejersted OM. Temperature-dependent skeletal muscle dysfunction in rats with congestive heart failure. J Appl Physiol (1985) 2005; 99:1500-7. [PMID: 15932960 DOI: 10.1152/japplphysiol.00807.2004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Abnormalities in the excitation-contraction coupling of slow-twitch muscle seem to explain the slowing and increased fatigue observed in congestive heart failure (CHF). However, it is not known which elements of the excitation-contraction coupling might be affected. We hypothesize that the temperature sensitivity of contractile properties of the soleus muscle might be altered in CHF possibly because of alterations of the temperature sensitivity of intracellular Ca(2+) handling. We electrically stimulated the in situ soleus muscle of anesthetised rats that had 6-wk postinfarction CHF using 1 and 50 Hz and using a fatigue protocol (5-Hz stimulation for 30 min) at 35, 37, and 40 degrees C. Ca(2+) uptake and release were measured in sarcoplasmic reticulum vesicles at various temperatures. Contraction and relaxation rates of the soleus muscle were slower in CHF than in sham at 35 degrees C, but the difference was almost absent at 40 degrees C. The fatigue protocol revealed that force development was more temperature sensitive in CHF, whereas contraction and relaxation rates were less temperature sensitive in CHF than in sham. The Ca(2+) uptake and release rates did not correlate to the difference between CHF and sham regarding contractile properties or temperature sensitivity. In conclusion, the discrepant results regarding altered temperature sensitivity of contraction and relaxation rates in the soleus muscle of CHF rats compared with Ca(2+) release and uptake rates in vesicles indicate that the molecular cause of slow-twitch muscle dysfunction in CHF is not linked to the intracellular Ca(2+) cycling.
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Affiliation(s)
- H-M Schiøtz Thorud
- Institute for Experimental Medical Research, Ullevaal University Hospital, Oslo, Norway
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19
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Schiøtz Thorud HM, Stranda A, Birkeland JA, Lunde PK, Sjaastad I, Kolset SO, Sejersted OM, Iversen PO. Enhanced matrix metalloproteinase activity in skeletal muscles of rats with congestive heart failure. Am J Physiol Regul Integr Comp Physiol 2005; 289:R389-R394. [PMID: 15802562 DOI: 10.1152/ajpregu.00067.2005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Patients with congestive heart failure (CHF) are prone to increased skeletal muscle fatigue. Elevated circulatory concentrations of tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein-1, which may stimulate matrix metalloproteinase (MMP) activity and, thereby, contribute to skeletal muscle dysfunction, are frequently found in CHF. However, whether skeletal muscle MMP activity is altered in CHF is unknown. Hence, we have used a gelatinase assay to assess the activity of MMP and tissue inhibitors of MMP in single skeletal muscles of rats with CHF 6 wk after induction of myocardial infarction. Sham-operated (Sham) rats were used as controls. We also measured the gene expression and protein contents of MMP-2 and MMP-9 in skeletal muscles of these rats. Plasma MMP activity was nearly seven times higher (P < 0.05) in CHF than in Sham rats. Concomitantly, the MMP activity within single slow- and fast-twitch skeletal muscles of CHF rats increased two- to fourfold compared with Sham animals, whereas tissue inhibitor of MMP activity did not differ (P > 0.05). Preformed MMP-2 and MMP-9 were probably activated in CHF, because neither their gene expression nor protein levels were altered (P > 0.05). Serum concentrations of TNF-alpha and monocyte chemoattractant protein-1 remained unchanged (P > 0.05) between CHF and Sham rats during the 6-wk observation period. We conclude that development of CHF in rats enhances MMP activity, which in turn may distort the normal contractile function of skeletal muscle, thereby contributing to increased skeletal muscle fatigue.
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20
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Vassort G, Lacampagne A. The role of ryanodine receptors and consequences of their alterations during cardiac insufficiency. Exp Clin Cardiol 2005; 10:196-199. [PMID: 19641687 PMCID: PMC2716251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Congestive heart failure (CHF) is a leading cause of death. Although changes to other components contribute, it is generally agreed that much of the contractile deficit is due to reduced Ca(2+) homeostasis that includes alterations in Ca(2+) current and action potential characteristics, together with reduced Ca(2+) transient amplitude. CHF is also associated with progressive skeletal muscle dysfunction. In both cardiac and skeletal muscles, the global increase in myoplasmic Ca(2+) during depolarization, or Ca(2+) transient, appears to consist of the summation of large numbers of local, unitary Ca(2+) release events (ie, Ca(2+) sparks) resulting from the activity of a cluster of ryanodine receptors (RyRs) (ie, RyR1 or RyR2 in skeletal and cardiac muscles, respectively). RyR2 channels from failing hearts have been shown to be hyperphosphorylated by protein kinase A, leading to dissociation of FK506-binding protein 12.6 and altered RyR2 channel function. After reviewing the alterations occurring in cardiomyocytes, the present report summarizes the intrinsic alterations of Ca(2+) homeostasis in rat extensor digitorum longus skeletal muscle. They include a weaker and prolonged Ca(2+) transient that could be attributed to both a lower synchronization of the individual Ca(2+) sparks and a lower synchronization of these events triggered upon depolarization. As in cardiac muscle, these alterations in sarcoplasmic reticulum function are associated with protein kinase A-induced hyperphosphorylation of RyR1 and a concomitant reduction in FK506-binding protein 12. These specific alterations in RyR1-dependent Ca(2+) release could play a significant role in the specific force decrements in skeletal muscle as well as in the remodelling that occurs secondary to CHF.
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Affiliation(s)
- Guy Vassort
- Correspondence: Dr Guy Vassort, INSERM U-637, Physiopathologie Cardiovasculaire, CHU Arnaud de Villeneuve, F-34295 Montpellier, France. Telephone 33-467-41-5248, fax 33-467-41-5242, e-mail
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21
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Kristensen M, Hansen T. Statistical analyses of repeated measures in physiological research: a tutorial. ADVANCES IN PHYSIOLOGY EDUCATION 2004; 28:2-14. [PMID: 14973047 DOI: 10.1152/advan.00042.2003] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Experimental designs involving repeated measurements on experimental units are widely used in physiological research. Often, relatively many consecutive observations on each experimental unit are involved and the data may be quite nonlinear. Yet evidently, one of the most commonly used statistical methods for dealing with such data sets in physiological research is the repeated-measurements ANOVA model. The problem herewith is that it is not well suited for data sets with many consecutive measurements; it does not deal with nonlinear features of the data, and the interpretability of the model may be low. The use of inappropriate statistical models increases the likelihood of drawing wrong conclusions. The aim of this article is to illustrate, for a reasonably typical repeated-measurements data set, how fundamental assumptions of the repeated-measurements ANOVA model are inappropriate and how researchers may benefit from adopting different modeling approaches using a variety of different kinds of models. We emphasize intuitive ideas rather than mathematical rigor. We illustrate how such models represent alternatives that 1) can have much higher interpretability, 2) are more likely to meet underlying assumptions, 3) provide better fitted models, and 4) are readily implemented in widely distributed software products.
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Affiliation(s)
- Michael Kristensen
- August Krogh Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
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22
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Schiøtz Thorud HM, Lunde PK, Nicolaysen G, Nicolaysen A, Helge JW, Nilsson GE, Sejersted OM. Muscle dysfunction during exercise of a single skeletal muscle in rats with congestive heart failure is not associated with reduced muscle blood supply. ACTA ACUST UNITED AC 2004; 181:173-81. [PMID: 15180789 DOI: 10.1111/j.1365-201x.2004.01285.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Inadequate muscle blood flow is a possible explanation for reduced fatigue resistance in patients with congestive heart failure (CHF). METHODS In rats with post-infarction CHF we electrically stimulated the soleus muscle (SOL) in situ with intact blood supply. Contractile properties, blood flow, high-energy phosphates and metabolites were measured during 30 min of intermittent stimulation, and in addition capillarization of SOL was recorded. RESULTS During stimulation, SOL contracted more slowly in rats with CHF compared with sham-operated rats. However, the blood flow in SOL was unaltered and capillary density was maintained in CHF rats. Further, the content of ATP, ADP, AMP, NAD, CrP, P(i) and lactate in SOL was not different between the groups. CONCLUSION The cause of contractile dysfunction in a single exercising skeletal muscle in rats with CHF cannot be explained simply by reduced blood supply. In addition, absence of changes in high-energy phosphates and metabolites indicate that the oxidative metabolism of SOL is intact in rats with CHF.
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Affiliation(s)
- H-M Schiøtz Thorud
- Institute for Experimental Medical Research, Ullevaal University Hospital, and Centre for Heart Failure Research, University of Oslo, Oslo, Norway
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23
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Dalla Libera L, Ravara B, Volterrani M, Gobbo V, Della Barbera M, Angelini A, Danieli Betto D, Germinario E, Vescovo G. Beneficial effects of GH/IGF-1 on skeletal muscle atrophy and function in experimental heart failure. Am J Physiol Cell Physiol 2003; 286:C138-44. [PMID: 13679302 DOI: 10.1152/ajpcell.00114.2003] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Muscle atrophy is a determinant of exercise capacity in heart failure (CHF). Myocyte apoptosis, triggered by tumor necrosis factor-alpha (TNF-alpha) or its second messenger sphingosine (SPH), is one of the causes of atrophy. Growth hormone (GH) improves hemodynamic and cardiac trophism in several experimental models of CHF, but its effect on skeletal muscle in CHF is not yet clear. We tested the hypothesis that GH can prevent skeletal muscle apoptosis in rats with CHF. CHF was induced by injecting monocrotaline. After 2 wk, 2 groups of rats were treated with GH (0.2 mg.kg(-1).day(-1) and 1.0 mg.kg(-1).day(-1)) subcutaneously. A third group of controls had saline. After 2 additional weeks, rats were killed. Tibialis anterior cross-sectional area, myosin heavy chain (MHC) composition, and a study on myocyte apoptosis and serum levels of TNF-alpha and SPH were carried out. The number of apoptotic nuclei, muscle atrophy, and serum levels of TNF-alpha and SPH were decreased with GH at high but not at low doses compared with CHF rats. Bcl-2 was increased, whereas activated caspases and bax were decreased. The MHC pattern in GH-treated animals was similar to that of controls. Monocrotaline slowed down both contraction and relaxation but did not affect specific tetanic force, whereas absolute force was decreased. GH treatment restored contraction and relaxation to control values and brought muscle mass and absolute twitch and tetanic tension to normal levels. These findings may provide an insight into the therapeutic strategy of GH given to patients with CHF to improve exercise capacity.
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Affiliation(s)
- Luciano Dalla Libera
- Internal Medicine II, Ospedale S. Bortolo, Viale Rodolfi 37, 36100 Vicenza, Italy.
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24
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Ward CW, Reiken S, Marks AR, Marty I, Vassort G, Lacampagne A. Defects in ryanodine receptor calcium release in skeletal muscle from post-myocardial infarct rats. FASEB J 2003; 17:1517-9. [PMID: 12824280 DOI: 10.1096/fj.02-1083fje] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Defective calcium (Ca2+) signaling and impaired contractile function have been observed in skeletal muscle secondary to impaired myocardial function. However, the molecular basis for these muscle defects have not been identified. In this study, we evaluated the alterations of the ryanodine-sensitive Ca2+ release channels (RyR1) by analyzing global and local Ca2+ signaling in a rat postmyocardial infarction (PMI) model of myocardial overload. Ca2+ transients, measured with multiphoton imaging in individual fibers within a whole extensor digitorum longus (EDL) muscle, exhibited significantly reduced amplitude and a prolonged time course in PMI. Spatio-temporal properties of spontaneous Ca2+ sparks in fibers isolated from PMI EDL muscles were also significantly altered. In addition, RyR1 from PMI skeletal muscles were PKA-hyperphosphorylated and depleted of the FK506 binding protein (FKBP12). These data show that PMI skeletal muscles exhibit altered local Ca2+ signaling, associated with hyperphosphorylation of RyR1. The observed changes in Ca2+ signaling may contribute to defective excitation-contraction coupling in muscle that can contribute to the reduced exercise capacity in PMI, out of proportion to the degree of cardiac dysfunction.
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Affiliation(s)
- C W Ward
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, USA
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25
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Reiken S, Lacampagne A, Zhou H, Kherani A, Lehnart SE, Ward C, Huang F, Gaburjakova M, Gaburjakova J, Rosemblit N, Warren MS, He KL, Yi GH, Wang J, Burkhoff D, Vassort G, Marks AR. PKA phosphorylation activates the calcium release channel (ryanodine receptor) in skeletal muscle: defective regulation in heart failure. J Cell Biol 2003; 160:919-28. [PMID: 12629052 PMCID: PMC2173774 DOI: 10.1083/jcb.200211012] [Citation(s) in RCA: 180] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The type 1 ryanodine receptor (RyR1) on the sarcoplasmic reticulum (SR) is the major calcium (Ca2+) release channel required for skeletal muscle excitation-contraction (EC) coupling. RyR1 function is modulated by proteins that bind to its large cytoplasmic scaffold domain, including the FK506 binding protein (FKBP12) and PKA. PKA is activated during sympathetic nervous system (SNS) stimulation. We show that PKA phosphorylation of RyR1 at Ser2843 activates the channel by releasing FKBP12. When FKB12 is bound to RyR1, it inhibits the channel by stabilizing its closed state. RyR1 in skeletal muscle from animals with heart failure (HF), a chronic hyperadrenergic state, were PKA hyperphosphorylated, depleted of FKBP12, and exhibited increased activity, suggesting that the channels are "leaky." RyR1 PKA hyperphosphorylation correlated with impaired SR Ca2+ release and early fatigue in HF skeletal muscle. These findings identify a novel mechanism that regulates RyR1 function via PKA phosphorylation in response to SNS stimulation. PKA hyperphosphorylation of RyR1 may contribute to impaired skeletal muscle function in HF, suggesting that a generalized EC coupling myopathy may play a role in HF.
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Affiliation(s)
- Steven Reiken
- Center for Molecular Cardiology, Box 65, Columbia University College of Physicians and Surgeons, Room 9-401, 630 West 168th Street, New York, NY 10032, USA
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