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Gu G, Hou D, Jiao G, Wu W, Zhou H, Wang H, Chen Y. Ortho-silicic Acid Plays a Protective Role in Glucocorticoid-Induced Osteoporosis via the Akt/Bad Signal Pathway In Vitro and In Vivo. Biol Trace Elem Res 2023; 201:843-855. [PMID: 35314965 DOI: 10.1007/s12011-022-03201-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 03/11/2022] [Indexed: 01/21/2023]
Abstract
Glucocorticoid-induced osteoporosis (GIOP) has been the most common form of secondary osteoporosis. Glucocorticoids (GCs) can induce osteocyte and osteoblast apoptosis. Plenty of research has verified that silicon intake would positively affect bone. However, the effects of silicon on GIOP are not investigated. In this study, we assessed the impact of ortho-silicic acid (OSA) on Dex-induced apoptosis of osteocytes by cell apoptosis assays. The apoptosis-related genes, cleaved-caspase-3, Bcl-2, and Bax, were detected by western blotting. Then, we evaluated the possible role of OSA on osteogenesis and osteoclastogenesis with Dex using Alizarin red staining and tartrate-resistant acid phosphatase (TRAP) staining. We also detected the related genes by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting. We then established the GIOP mouse model to evaluate the potential role of OSA in vivo. We found that OSA showed no cytotoxic on osteocytes below 50 μM and prevented MLO-Y4 from Dex-induced apoptosis. We also found that OSA promoted osteogenesis and inhibited osteoclastogenesis with Dex. OSA had a protective effect on GIOP mice via the Akt signal pathway in vivo. In the end, we verified the Akt/Bad signal pathway in vitro, which showed the same results. Our finding demonstrated that OSA could protect osteocytes from apoptosis induced by GCs both in vitro and in vivo. Also, it promoted osteogenesis and inhibited osteoclastogenesis with the exitance of Dex. In conclusion, OSA has the potential value as a therapeutic agent for GIOP.
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Affiliation(s)
- Guanghui Gu
- Qilu Hospital of Shandong University, Jinan, Shandong, China
- Department of Spine Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Dehui Hou
- Qilu Hospital of Shandong University, Jinan, Shandong, China
- Department of Spine Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Guangjun Jiao
- Department of Spine Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Wenliang Wu
- Department of Spine Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Hongming Zhou
- Department of Spine Surgery, Linyi Central Hospital, Linyi, Shandong, China
| | - Hongliang Wang
- Department of Spine Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Yunzhen Chen
- Department of Spine Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China.
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Mitochondrial Glucocorticoid Receptors and Their Actions. Int J Mol Sci 2021; 22:ijms22116054. [PMID: 34205227 PMCID: PMC8200016 DOI: 10.3390/ijms22116054] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 05/27/2021] [Accepted: 05/29/2021] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are membrane organelles present in almost all eukaryotic cells. In addition to their well-known role in energy production, mitochondria regulate central cellular processes, including calcium homeostasis, Reactive Oxygen Species (ROS) generation, cell death, thermogenesis, and biosynthesis of lipids, nucleic acids, and steroid hormones. Glucocorticoids (GCs) regulate the mitochondrially encoded oxidative phosphorylation gene expression and mitochondrial energy metabolism. The identification of Glucocorticoid Response Elements (GREs) in mitochondrial sequences and the detection of Glucocorticoid Receptor (GR) in mitochondria of different cell types gave support to hypothesis that mitochondrial GR directly regulates mitochondrial gene expression. Numerous studies have revealed changes in mitochondrial gene expression alongside with GR import/export in mitochondria, confirming the direct effects of GCs on mitochondrial genome. Further evidence has made clear that mitochondrial GR is involved in mitochondrial function and apoptosis-mediated processes, through interacting or altering the distribution of Bcl2 family members. Even though its exact translocation mechanisms remain unknown, data have shown that GR chaperones (Hsp70/90, Bag-1, FKBP51), the anti-apoptotic protein Bcl-2, the HDAC6- mediated deacetylation and the outer mitochondrial translocation complexes (Tom complexes) co-ordinate GR mitochondrial trafficking. A role of mitochondrial GR in stress and depression as well as in lung and hepatic inflammation has also been demonstrated.
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Dubinin MV, Talanov EY, Tenkov KS, Starinets VS, Belosludtseva NV, Belosludtsev KN. The Effect of Deflazacort Treatment on the Functioning of Skeletal Muscle Mitochondria in Duchenne Muscular Dystrophy. Int J Mol Sci 2020; 21:E8763. [PMID: 33228255 PMCID: PMC7699511 DOI: 10.3390/ijms21228763] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/17/2020] [Accepted: 11/17/2020] [Indexed: 01/10/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe hereditary disease caused by a lack of dystrophin, a protein essential for myocyte integrity. Mitochondrial dysfunction is reportedly responsible for DMD. This study examines the effect of glucocorticoid deflazacort on the functioning of the skeletal-muscle mitochondria of dystrophin-deficient mdx mice and WT animals. Deflazacort administration was found to improve mitochondrial respiration of mdx mice due to an increase in the level of ETC complexes (complexes III and IV and ATP synthase), which may contribute to the normalization of ATP levels in the skeletal muscle of mdx animals. Deflazacort treatment improved the rate of Ca2+ uniport in the skeletal muscle mitochondria of mdx mice, presumably by affecting the subunit composition of the calcium uniporter of organelles. At the same time, deflazacort was found to reduce the resistance of skeletal mitochondria to MPT pore opening, which may be associated with a change in the level of ANT2 and CypD. In this case, deflazacort also affected the mitochondria of WT mice. The paper discusses the mechanisms underlying the effect of deflazacort on the functioning of mitochondria and contributing to the improvement of the muscular function of mdx mice.
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MESH Headings
- Adenine Nucleotide Translocator 2/genetics
- Adenine Nucleotide Translocator 2/metabolism
- Adenosine Triphosphate/biosynthesis
- Animals
- Calcium/metabolism
- Calcium Channels/genetics
- Calcium Channels/metabolism
- Peptidyl-Prolyl Isomerase F/genetics
- Peptidyl-Prolyl Isomerase F/metabolism
- Electron Transport Complex III/genetics
- Electron Transport Complex III/metabolism
- Electron Transport Complex IV/genetics
- Electron Transport Complex IV/metabolism
- Gene Expression Regulation/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/genetics
- Mitochondria, Muscle/metabolism
- Mitochondrial Proton-Translocating ATPases/genetics
- Mitochondrial Proton-Translocating ATPases/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Duchenne/drug therapy
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Pregnenediones/pharmacology
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Affiliation(s)
- Mikhail V. Dubinin
- Department of Biochemistry, Cell Biology and Microbiology, Mari State University, pl. Lenina 1, 424001 Yoshkar-Ola, Russia; (K.S.T.); (V.S.S.); (K.N.B.)
| | - Eugeny Yu. Talanov
- Laboratory of Mitochondrial Transport, Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (E.Y.T.); (N.V.B.)
| | - Kirill S. Tenkov
- Department of Biochemistry, Cell Biology and Microbiology, Mari State University, pl. Lenina 1, 424001 Yoshkar-Ola, Russia; (K.S.T.); (V.S.S.); (K.N.B.)
| | - Vlada S. Starinets
- Department of Biochemistry, Cell Biology and Microbiology, Mari State University, pl. Lenina 1, 424001 Yoshkar-Ola, Russia; (K.S.T.); (V.S.S.); (K.N.B.)
- Laboratory of Mitochondrial Transport, Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (E.Y.T.); (N.V.B.)
| | - Natalia V. Belosludtseva
- Laboratory of Mitochondrial Transport, Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (E.Y.T.); (N.V.B.)
| | - Konstantin N. Belosludtsev
- Department of Biochemistry, Cell Biology and Microbiology, Mari State University, pl. Lenina 1, 424001 Yoshkar-Ola, Russia; (K.S.T.); (V.S.S.); (K.N.B.)
- Biophotonics Center, Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov st. 38, 119991 Moscow, Russia
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Skeletal Muscle Response to Deflazacort, Dexamethasone and Methylprednisolone. Cells 2019; 8:cells8050406. [PMID: 31052442 PMCID: PMC6562646 DOI: 10.3390/cells8050406] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/07/2019] [Accepted: 04/23/2019] [Indexed: 12/27/2022] Open
Abstract
Glucocorticoids represent some of the most prescribed drugs that are widely used in the treatment of neuromuscular diseases, but their usage leads to side effects such as muscle atrophy. However, different synthetic glucocorticoids can lead to different muscle effects, depending upon its chemical formulation. Here, we intended to demonstrate the muscle histologic and molecular effects of administering different glucocorticoids in equivalency and different dosages. Methods: Seventy male Wistar rats distributed into seven groups received different glucocorticoids in equivalency for ten days or saline solution. The study groups were: Control group (CT) saline solution; dexamethasone (DX) 1.25 or 2.5 mg/kg/day; methylprednisolone (MP) 6.7 or 13.3mg/kg/day; and deflazacort (DC) 10 or 20 mg/kg/day. At the end of the study, the animals were euthanized, and the tibialis anterior and gastrocnemius muscles were collected for metachromatic ATPase (Cross-sectional area (CSA) measurement), Western blotting (protein expression of IGF-1 and Ras/Raf/MEK/ERK pathways) and RT-PCR (MYOSTATIN, MuRF-1, Atrogin-1, REDD-1, REDD-2, MYOD, MYOG and IRS1/2 genes expression) experiments. Results: Muscle atrophy occurred preferentially in type 2B fibers in all glucocorticoid treated groups. DC on 10 mg/kg/day was less harmful to type 2B fibers CSA than other doses and types of synthetic glucocorticoids. In type 1 fibers CSA, lower doses of DC and DX were more harmful than high doses. DX had a greater effect on the IGF-1 pathway than other glucocorticoids. MP more significantly affected P-ERK1/2 expression, muscle fiber switching (fast-to-slow), and expression of REDD1 and MyoD genes than other glucocorticoids. Compared to DX and MP, DC had less of an effect on the expression of atrogenes (MURF-1 and Atrogin-1) despite increased MYOSTATIN and decreased IRS-2 genes expression. Conclusions: Different glucocorticoids appears to cause muscle atrophy affecting secondarily different signaling mechanisms. MP is more likely to affect body/muscles mass, MEK/ERK pathway and fiber type transition, DX the IGF-1 pathway and IRS1/2 expression. DC had the smallest effect on muscle atrophic response possibly due a delayed timing on atrogenes response.
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Usmanovich A, Rustemovic R, Iskhakovic A, Evgenyevic A, Nikolaevic S. Foot-shock Stimulation Decreases the Inhibitory Action of ATP on Contractility and End-plate Current of Frog Sartorius Muscle. INT J PHARMACOL 2018. [DOI: 10.3923/ijp.2018.1198.1202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Sreetama SC, Chandra G, Van der Meulen JH, Ahmad MM, Suzuki P, Bhuvanendran S, Nagaraju K, Hoffman EP, Jaiswal JK. Membrane Stabilization by Modified Steroid Offers a Potential Therapy for Muscular Dystrophy Due to Dysferlin Deficit. Mol Ther 2018; 26:2231-2242. [PMID: 30166241 PMCID: PMC6127637 DOI: 10.1016/j.ymthe.2018.07.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 07/15/2018] [Accepted: 07/24/2018] [Indexed: 11/16/2022] Open
Abstract
Mutations of the DYSF gene leading to reduced dysferlin protein level causes limb girdle muscular dystrophy type 2B (LGMD2B). Dysferlin facilitates sarcolemmal membrane repair in healthy myofibers, thus its deficit compromises myofiber repair and leads to chronic muscle inflammation. An experimental therapeutic approach for LGMD2B is to protect damage or improve repair of myofiber sarcolemma. Here, we compared the effects of prednisolone and vamorolone (a dissociative steroid; VBP15) on dysferlin-deficient myofiber repair. Vamorolone, but not prednisolone, stabilized dysferlin-deficient muscle cell membrane and improved repair of dysferlin-deficient mouse (B6A/J) myofibers injured by focal sarcolemmal damage, eccentric contraction-induced injury or injury due to spontaneous in vivo activity. Vamorolone decreased sarcolemmal lipid mobility, increased muscle strength, and decreased late-stage myofiber loss due to adipogenic infiltration. In contrast, the conventional glucocorticoid prednisolone failed to stabilize dysferlin deficient muscle cell membrane or improve repair of dysferlinopathic patient myoblasts and mouse myofibers. Instead, prednisolone treatment increased muscle weakness and myofiber atrophy in B6A/J mice—findings that correlate with reports of prednisolone worsening symptoms of LGMD2B patients. Our findings showing improved cellular and pre-clinical efficacy of vamorolone compared to prednisolone and better safety profile of vamorolone indicates the suitability of vamorolone for clinical trials in LGMD2B.
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Affiliation(s)
- Sen Chandra Sreetama
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Goutam Chandra
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Jack H Van der Meulen
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Mohammad Mahad Ahmad
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Peter Suzuki
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Shivaprasad Bhuvanendran
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Kanneboyina Nagaraju
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Binghamton University, Binghamton, NY 13902, USA
| | - Eric P Hoffman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Binghamton University, Binghamton, NY 13902, USA
| | - Jyoti K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA; Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA.
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7
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Rocha Arrieta YC, Rojas M, Vasquez G, Lopez J. The Lymphocytes Stimulation Induced DNA Release, a Phenomenon Similar to NETosis. Scand J Immunol 2017; 86:229-238. [PMID: 28805301 DOI: 10.1111/sji.12592] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 07/30/2017] [Indexed: 12/23/2022]
Abstract
The release of DNA into the extracellular milieu by neutrophil during a process called NETosis has been postulated as an additional source of autoantigens; a process believed to be important in the pathogenesis of some autoimmune disease, such as systemic lupus erythematosus (SLE). However, it is not established if the B and T cells undergo the release of DNA to the extracellular milleu, in response to different stimuli. In this study, it was observed that the treatment of B and T cells with PMA, ionomycin and the serum from patients with SLE induced the extracellular DNA presence in B and T cells. These findings suggest that the phenomenon were similar to those observed in neutrophil's Etosis; B and T cells also released their DNA into the extracellular milieu. The findings express that serum from patients with SLE and SLEDAI ≤ 8 triggers the release of extracellular DNA in neutrophils, B and T cells, that suggested the presence of soluble factors in the serum that favoured this phenomenon.
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Affiliation(s)
- Y C Rocha Arrieta
- Grupo de Inmunodeficiencias Primarias/Lab 530-531, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - M Rojas
- Unidad de Citometría/Lab 420, Instituto de Investigaciones Médicas, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.,Grupo de Inmunología Celular e Inmunogenética/Lab 510-511, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - G Vasquez
- Grupo de Inmunología Celular e Inmunogenética/Lab 510-511, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - J Lopez
- Grupo de Inmunodeficiencias Primarias/Lab 530-531, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
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8
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Johnstone VPA, Viola HM, Hool LC. Dystrophic Cardiomyopathy-Potential Role of Calcium in Pathogenesis, Treatment and Novel Therapies. Genes (Basel) 2017; 8:genes8040108. [PMID: 28338606 PMCID: PMC5406855 DOI: 10.3390/genes8040108] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/16/2017] [Accepted: 03/21/2017] [Indexed: 01/06/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is caused by defects in the DMD gene and results in progressive wasting of skeletal and cardiac muscle due to an absence of functional dystrophin. Cardiomyopathy is prominent in DMD patients, and contributes significantly to mortality. This is particularly true following respiratory interventions that reduce death rate and increase ambulation and consequently cardiac load. Cardiomyopathy shows an increasing prevalence with age and disease progression, and over 95% of patients exhibit dilated cardiomyopathy by the time they reach adulthood. Development of the myopathy is complex, and elevations in intracellular calcium, functional muscle ischemia, and mitochondrial dysfunction characterise the pathophysiology. Current therapies are limited to treating symptoms of the disease and there is therefore an urgent need to treat the underlying genetic defect. Several novel therapies are outlined here, and the unprecedented success of phosphorodiamidate morpholino oligomers (PMOs) in preclinical and clinical studies is overviewed.
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Affiliation(s)
- Victoria P A Johnstone
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Helena M Viola
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Livia C Hool
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
- Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia.
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Tsompos C, Panoulis C, Toutouzas K, Zografos G, Papalois A. The Acute Effect of the Antioxidant Drug U-74389G on Red Blood Cell Distribution Width Levels During Hypoxia Reoxygenation Injury in Rats. Folia Med (Plovdiv) 2016; 57:235-42. [PMID: 27180351 DOI: 10.1515/folmed-2015-0044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 02/09/2016] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED The AIM of this experimental study was to evaluate the effect of the antioxidant drug "U-74389G" in a rat model of hypoxia reoxygenation (HR) using the previously established protocol. Effects of treatment were evaluated by mean red blood cell distribution width (RDW) levels. MATERIALS AND METHODS 40 rats of a mean weight of 231.875 g were employed in the study. RDW levels were determined at 60 min (groups A and C) and at 120 min (groups B and D) after starting the reoxygenation. Groups A and B received no drugs, whereas rats from groups C and D were administered with U-74389G. RESULTS demonstrated that U-74389G administration significantly decreased the RDW levels by 4.96% + 2.27% (p = 0.0175). Reoxygenation time non-significantly decreased the RDW levels by 0.27% + 2.41% (p = 0.8889). Together, U-74389G administration and reoxygenation time non-significantly decreased the RDW levels by 2.54% + 1.39% (p = 0.0679). CONCLUSIONS U-74389G administration particulary in concert without reperfusion declines the RDW levels even within the short - time context of 1.5 hours reperfusion.
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Affiliation(s)
- Constantinos Tsompos
- Department of Obstetrics & Gynecology, Mesologi County Hospital, Etoloakarnania, Greece
| | | | | | - George Zografos
- Department of Surgery, Ippokrateion General Hospital, Athens University, Attiki, Greece
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Gong H, Liu L, Ni CX, Zhang Y, Su WJ, Lian YJ, Peng W, Zhang JP, Jiang CL. Dexamethasone rapidly inhibits glucose uptake via non-genomic mechanisms in contracting myotubes. Arch Biochem Biophys 2016; 603:102-9. [PMID: 27246478 DOI: 10.1016/j.abb.2016.05.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 12/31/2022]
Abstract
Glucocorticoids (GCs) are a class of steroid hormones that regulate multiple aspects of glucose homeostasis. In skeletal muscle, it is well established that prolonged GC excess inhibits glucose uptake and utilization through glucocorticoid receptor (GR)-mediated transcriptional changes. However, it remains obscure that whether the rapid non-genomic effects of GC on glucose uptake are involved in acute exercise stress. Therefore, we used electric pulse stimulation (EPS)-evoked contracting myotubes to determine whether the non-genomic actions of GC were involved and its underlying mechanism(s). Pretreatment with dexamethasone (Dex, 10 μM) significantly prevented contraction-stimulated glucose uptake and glucose transporter 4 (Glut4) translocation within 20 min in C2C12 myotubes. Neither GC nuclear receptor antagonist (RU486) nor protein synthesis inhibitor (cycloheximide, Chx) affected the rapid inhibition effects of Dex. AMPK and CaMKII-dependent signaling pathways were associated with the non-genomic effects of Dex. These results provide evidence that GC rapidly suppresses glucose uptake in contracting myotubes via GR-independent non-genomic mechanisms. AMPK and CaMKII-mediated Glut4 translocation may play a critical role in GC-induced rapid inhibition of glucose uptake.
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Affiliation(s)
- Hong Gong
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Lei Liu
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Chen-Xu Ni
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, People's Republics of China
| | - Yi Zhang
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Wen-Jun Su
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Yong-Jie Lian
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Wei Peng
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Jun-Ping Zhang
- Department of Pharmacy, Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Chun-Lei Jiang
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, Shanghai 200433, People's Republic of China.
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Matthews E, Brassington R, Kuntzer T, Jichi F, Manzur AY. Corticosteroids for the treatment of Duchenne muscular dystrophy. Cochrane Database Syst Rev 2016; 2016:CD003725. [PMID: 27149418 PMCID: PMC8580515 DOI: 10.1002/14651858.cd003725.pub4] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy of childhood. Untreated, this incurable disease, which has an X-linked recessive inheritance, is characterised by muscle wasting and loss of walking ability, leading to complete wheelchair dependence by 13 years of age. Prolongation of walking is a major aim of treatment. Evidence from randomised controlled trials (RCTs) indicates that corticosteroids significantly improve muscle strength and function in boys with DMD in the short term (six months), and strength at two years (two-year data on function are very limited). Corticosteroids, now part of care recommendations for DMD, are largely in routine use, although questions remain over their ability to prolong walking, when to start treatment, longer-term balance of benefits versus harms, and choice of corticosteroid or regimen.We have extended the scope of this updated review to include comparisons of different corticosteroids and dosing regimens. OBJECTIVES To assess the effects of corticosteroids on prolongation of walking ability, muscle strength, functional ability, and quality of life in DMD; to address the question of whether benefit is maintained over the longer term (more than two years); to assess adverse events; and to compare efficacy and adverse effects of different corticosteroid preparations and regimens. SEARCH METHODS On 16 February 2016 we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, EMBASE, CINAHL Plus, and LILACS. We wrote to authors of published studies and other experts. We checked references in identified trials, handsearched journal abstracts, and searched trials registries. SELECTION CRITERIA We considered RCTs or quasi-RCTs of corticosteroids (e.g. prednisone, prednisolone, and deflazacort) given for a minimum of three months to patients with a definite DMD diagnosis. We considered comparisons of different corticosteroids, regimens, and corticosteroids versus placebo. DATA COLLECTION AND ANALYSIS The review authors followed standard Cochrane methodology. MAIN RESULTS We identified 12 studies (667 participants) and two new ongoing studies for inclusion. Six RCTs were newly included at this update and important non-randomised cohort studies have also been published. Some important studies remain unpublished and not all published studies provide complete outcome data. PRIMARY OUTCOME MEASURE one two-year deflazacort RCT (n = 28) used prolongation of ambulation as an outcome measure but data were not adequate for drawing conclusions. SECONDARY OUTCOME MEASURES meta-analyses showed that corticosteroids (0.75 mg/kg/day prednisone or prednisolone) improved muscle strength and function versus placebo over six months (moderate quality evidence from up to four RCTs). Evidence from single trials showed 0.75 mg/kg/day superior to 0.3 mg/kg/day on most strength and function measures, with little evidence of further benefit at 1.5 mg/kg/day. Improvements were seen in time taken to rise from the floor (Gowers' time), timed walk, four-stair climbing time, ability to lift weights, leg function grade, and forced vital capacity. One new RCT (n = 66), reported better strength, function and quality of life with daily 0.75 mg/kg/day prednisone at 12 months. One RCT (n = 28) showed that deflazacort stabilised muscle strength versus placebo at two years, but timed function test results were too imprecise for conclusions to be drawn.One double-blind RCT (n = 64), largely at low risk of bias, compared daily prednisone (0.75 mg/kg/day) with weekend-only prednisone (5 mg/kg/weekend day), finding no overall difference in muscle strength and function over 12 months (moderate to low quality evidence). Two small RCTs (n = 52) compared daily prednisone 0.75 mg/kg/day with daily deflazacort 0.9 mg/kg/day, but study methods limited our ability to compare muscle strength or function. ADVERSE EFFECTS excessive weight gain, behavioural abnormalities, cushingoid appearance, and excessive hair growth were all previously shown to be more common with corticosteroids than placebo; we assessed the quality of evidence (for behavioural changes and weight gain) as moderate. Hair growth and cushingoid features were more frequent at 0.75 mg/kg/day than 0.3 mg/kg/day prednisone. Comparing daily versus weekend-only prednisone, both groups gained weight with no clear difference in body mass index (BMI) or in behavioural changes (low quality evidence for both outcomes, one study); the weekend-only group had a greater linear increase in height. Very low quality evidence suggested less weight gain with deflazacort than with prednisone at 12 months, and no difference in behavioural abnormalities. Data are insufficient to assess the risk of fractures or cataracts for any comparison.Non-randomised studies support RCT evidence in showing improved functional benefit from corticosteroids. These studies suggest sustained benefit for up to 66 months. Adverse effects were common, although generally manageable. According to a large comparative longitudinal study of daily or intermittent (10 days on, 10 days off) corticosteroid for a mean period of four years, a daily regimen prolongs ambulation and improves functional scores over the age of seven, but with a greater frequency of side effects than an intermittent regimen. AUTHORS' CONCLUSIONS Moderate quality evidence from RCTs indicates that corticosteroid therapy in DMD improves muscle strength and function in the short term (twelve months), and strength up to two years. On the basis of the evidence available for strength and function outcomes, our confidence in the effect estimate for the efficacy of a 0.75 mg/kg/day dose of prednisone or above is fairly secure. There is no evidence other than from non-randomised trials to establish the effect of corticosteroids on prolongation of walking. In the short term, adverse effects were significantly more common with corticosteroids than placebo, but not clinically severe. A weekend-only prednisone regimen is as effective as daily prednisone in the short term (12 months), according to low to moderate quality evidence from a single trial, with no clear difference in BMI (low quality evidence). Very low quality evidence indicates that deflazacort causes less weight gain than prednisone after a year's treatment. We cannot evaluate long-term benefits and hazards of corticosteroid treatment or intermittent regimens from published RCTs. Non-randomised studies support the conclusions of functional benefits, but also identify clinically significant adverse effects of long-term treatment, and a possible divergence of efficacy in daily and weekend-only regimens in the longer term. These benefits and adverse effects have implications for future research and clinical practice.
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Affiliation(s)
- Emma Matthews
- National Hospital for Neurology and NeurosurgeryMRC Centre for Neuromuscular DiseasesQueen SquareLondonUK
| | - Ruth Brassington
- National Hospital for Neurology and NeurosurgeryMRC Centre for Neuromuscular DiseasesQueen SquareLondonUK
| | - Thierry Kuntzer
- CHU Vaudois and University of LausanneNerve‐Muscle Unit, Service of NeurologyLausanneSwitzerland1011
| | - Fatima Jichi
- Joint Research Office, University College LondonUCL School of Life & Medical SciencesGower StreetLondonUKWC1E 6BT
| | - Adnan Y Manzur
- Great Ormond Street Hospital for Children NHS TrustDubowitz Neuromuscular CentreGreat Ormond StreetLondonUKWC1N 3JH
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Shimizu-Motohashi Y, Asakura Y, Motohashi N, Belur NR, Baumrucker MG, Asakura A. Pregnancy-induced amelioration of muscular dystrophy phenotype in mdx mice via muscle membrane stabilization effect of glucocorticoid. PLoS One 2015; 10:e0120325. [PMID: 25775477 PMCID: PMC4361742 DOI: 10.1371/journal.pone.0120325] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 01/20/2015] [Indexed: 12/16/2022] Open
Abstract
Duchenne muscular dystrophy (DMD), the most common and severe type of dystrophinopathy, is an X-linked recessive genetic disease caused by the absence of dystrophin, which leads to fragility and vulnerability of the sarcolemma to mechanical stretching with increased membrane permeability. Currently, glucocorticoids such as prednisolone are the only medication available for DMD. However, molecular pathways responsible for this effect are still unclear. In addition, it remains unclear whether sex-related factors, including pregnancy and the postpartum period, affect the phenotype of dystrophinopathy. Here, we report the amelioration of muscle membrane permeability in the diaphragm muscle of pregnant and postpartum, but not in nulliparous, mdx mice, an animal model for DMD, during the physiological surge of corticosterone, the most abundant glucocorticoid in rodents. Cultures of single muscle fibers and myotubes isolated from mdx mouse diaphragm demonstrate resistance to hypo-osmotic shock when treated with corticosterone but not with estradiol or progesterone. This corticosterone-mediated resistance was diminished by an antagonist of corticosterone, indicating that the glucocorticoid-glucocorticoid receptor axis plays a role in this membrane stabilization effect on muscle. Moreover, subcutaneous injection of corticosterone into mdx mice showed decreased membrane permeability. This is the first report to demonstrate that pregnancy-related resistance to muscle fiber damage in mdx mice due to the membrane stabilization effect of corticosterone. We also propose that this membrane stabilization effect is exerted through annexin A1 up-regulation as the molecular mechanisms of glucocorticoid effects on DMD muscle. Furthermore, single muscle fiber culture studies provide a sensitive chemical screening platform for muscular dystrophies.
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Affiliation(s)
- Yuko Shimizu-Motohashi
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Yoko Asakura
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Norio Motohashi
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Nandkishore R. Belur
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Michael G. Baumrucker
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Atsushi Asakura
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, United States of America
- * E-mail:
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13
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Corticosteroid Treatment Impact on Spinal Deformity in Duchenne Muscular Dystrophy. INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:965235. [PMID: 27382620 PMCID: PMC4897302 DOI: 10.1155/2014/965235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 08/24/2014] [Indexed: 01/03/2023]
Abstract
Duchenne muscular dystrophy is a progressive disease with loss of ambulation at around 9-10 years of age, followed, if untreated, by development of scoliosis, respiratory insufficiency, and death in the second decade of life. This review highlights the natural history of the disease, in particular, with regard to the development of the spinal deformity and how this complication has been modified by surgical interventions and overall by corticosteroid treatment. The beneficial effect of corticosteroids may have also an impact on the clinical trial design of the new emerging causative therapies.
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14
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Ismail HM, Dorchies OM, Perozzo R, Strosova MK, Scapozza L, Ruegg UT. Inhibition of iPLA2 β and of stretch-activated channels by doxorubicin alters dystrophic muscle function. Br J Pharmacol 2014; 169:1537-50. [PMID: 23849042 DOI: 10.1111/bph.12188] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 02/28/2013] [Accepted: 03/15/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Chronic elevation in intracellular Ca(2+) concentration participates in death of skeletal muscle from mdx mice, a model for Duchenne muscular dystrophy (DMD). Candidate pathways mediating this Ca(2+) overload involve store-operated channels (SOCs) and stretch-activated channels (SACs), which are modulated by the Ca(2+) -independent form of PL A2 (iPLA2 ). We investigated the effect of doxorubicin (Dox), a chemotherapeutic agent reported to inhibit iPLA2 in other systems, on the activity of this enzyme and on the consequences on Ca(2+) handling and muscle function in mdx mice. EXPERIMENTAL APPROACH Effects of Dox on iPLA2 activity, reactive oxygen species production and on Ca(2+) influx were investigated in C2C12 and mdx myotubes. The mechanism of Dox-mediated iPLA2 inhibition was evaluated using purified 6x histidine-tagged enzyme. Aequorin technology was used to assess Ca(2+) concentrations underneath the plasma membrane. Isolated muscles were exposed to fatigue protocols and eccentric contractions to evaluate the effects of Dox on muscle function. KEY RESULTS Dox at 1-30 μM inhibited iPLA2 activity in cells and in the purified enzyme. Dox also inhibited SAC- but not SOC-mediated Ca(2+) influx in myotubes. Stimulated elevations of Ca(2+) concentrations below the plasmalemma were also blocked. Exposure of excised muscle to Dox was not deleterious to force production and promoted recovery from eccentric contractions. CONCLUSIONS AND IMPLICATIONS Dox showed efficacy against targets known to play a role in the pathology of DMD, namely iPLA2 and SAC. The potent SAC inhibitory effect of Dox is a novel finding that can explain partly the cardiomyopathy seen in chronic anthracycline treatment.
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Affiliation(s)
- H M Ismail
- Pharmacology, Geneva-Lausanne School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva, Switzerland
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15
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An HT, Kim J, Yoo S, Ko J. Small leucine zipper protein (sLZIP) negatively regulates skeletal muscle differentiation via interaction with α-actinin-4. J Biol Chem 2013; 289:4969-79. [PMID: 24375477 DOI: 10.1074/jbc.m113.515395] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The small leucine zipper protein (sLZIP) plays a role in transcriptional regulation in various types of cells. However, the role of sLZIP in myogenesis is unknown. We identified α-actinin-4 (ACTN4) as a sLZIP-binding protein. ACTN4 functions as a transcriptional regulator of myocyte enhancer factor (MEF)2, which plays a critical role in expression of muscle-specific genes during skeletal muscle differentiation. We found that ACTN4 translocates to the nucleus, induces myogenic gene expression, and promotes myotube formation during myogenesis. The myogenic process is controlled by an association between myogenic factors and MEF2 transcription factors. ACTN4 increased expression of muscle-specific proteins via interaction with MEF2. However, sLZIP decreased myogenic gene expression and myotube formation during myogenesis via disruption of the association between ACTN4 and MEF2. ACTN4 increased the promoter activities of myogenic genes, whereas sLZIP abrogated the effect of ACTN4 on transcriptional activation of myogenic genes in myoblasts. The C terminus of sLZIP is required for interaction with the C terminus of ACTN4, based on deletion mutant analysis, and sLZIP plays a role in regulation of MEF2 transactivation via interaction with ACTN4. Our results indicate that sLZIP negatively regulates skeletal muscle differentiation via interaction with ACTN4 and that sLZIP can be used as a therapeutic target molecule for treatment of muscle hypertrophy and associated diseases.
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Affiliation(s)
- Hyoung-Tae An
- From the Division of Life Sciences, Korea University, Seoul 136-701, South Korea
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16
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Hoffman EP, Reeves E, Damsker J, Nagaraju K, McCall JM, Connor EM, Bushby K. Novel approaches to corticosteroid treatment in Duchenne muscular dystrophy. Phys Med Rehabil Clin N Am 2013; 23:821-8. [PMID: 23137739 DOI: 10.1016/j.pmr.2012.08.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although prednisone has never been formally approved for use in Duchenne muscular dystrophy (DMD) by regulatory agencies, its efficacy has been confirmed in trials dating from the 1980s. There is a strong need for optimization of both specific type of glucocorticoid (eg, prednisone, vs deflazacort or others) and the dosing regimen. Ideally an optimized regimen would maximize efficacy while minimizing side-effect profiles. A new trial, FOR-DMD, aims to address this gap in knowledge. In parallel, there has been progress in the area of "dissociative steroids," drugs that are able to better separate efficacy and side effects, providing a broader therapeutic window.
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Affiliation(s)
- Eric P Hoffman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
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17
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Baudy AR, Reeves EKM, Damsker JM, Heier C, Garvin LM, Dillingham BC, McCall J, Rayavarapu S, Wang Z, Vandermeulen JH, Sali A, Jahnke V, Duguez S, DuBois D, Rose MC, Nagaraju K, Hoffman EP. Δ-9,11 modification of glucocorticoids dissociates nuclear factor-κB inhibitory efficacy from glucocorticoid response element-associated side effects. J Pharmacol Exp Ther 2012; 343:225-32. [PMID: 22743576 DOI: 10.1124/jpet.112.194340] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glucocorticoids are standard of care for many inflammatory conditions, but chronic use is associated with a broad array of side effects. This has led to a search for dissociative glucocorticoids--drugs able to retain or improve efficacy associated with transrepression [nuclear factor-κB (NF-κB) inhibition] but with the loss of side effects associated with transactivation (receptor-mediated transcriptional activation through glucocorticoid response element gene promoter elements). We investigated a glucocorticoid derivative with a Δ-9,11 modification as a dissociative steroid. The Δ-9,11 analog showed potent inhibition of tumor necrosis factor-α-induced NF-κB signaling in cell reporter assays, and this transrepression activity was blocked by 17β-hydroxy-11β-[4-dimethylamino phenyl]-17α-[1-propynyl]estra-4,9-dien-3-one (RU-486), showing the requirement for the glucocorticoid receptor (GR). The Δ-9,11 analog induced the nuclear translocation of GR but showed the loss of transactivation as assayed by GR-luciferase constructs as well as mRNA profiles of treated cells. The Δ-9,11 analog was tested for efficacy and side effects in two mouse models of muscular dystrophy: mdx (dystrophin deficiency), and SJL (dysferlin deficiency). Daily oral delivery of the Δ-9,11 analog showed a reduction of muscle inflammation and improvements in multiple muscle function assays yet no reductions in body weight or spleen size, suggesting the loss of key side effects. Our data demonstrate that a Δ-9,11 analog dissociates the GR-mediated transcriptional activities from anti-inflammatory activities. Accordingly, Δ-9,11 analogs may hold promise as a source of safer therapeutic agents for chronic inflammatory disorders.
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Affiliation(s)
- Andreas R Baudy
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
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18
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Crewther BT, Cook C, Cardinale M, Weatherby RP, Lowe T. Two Emerging Concepts for Elite Athletes. Sports Med 2011; 41:103-23. [DOI: 10.2165/11539170-000000000-00000] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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19
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Crewther BT, Heke T, Keogh JWL. The Effects of Training Volume and Competition on the Salivary Cortisol Concentrations of Olympic Weightlifters. J Strength Cond Res 2011; 25:10-5. [DOI: 10.1519/jsc.0b013e3181fb47f5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Banerjee B, Sharma U, Balasubramanian K, Kalaivani M, Kalra V, Jagannathan NR. Effect of creatine monohydrate in improving cellular energetics and muscle strength in ambulatory Duchenne muscular dystrophy patients: a randomized, placebo-controlled 31P MRS study. Magn Reson Imaging 2010; 28:698-707. [PMID: 20395096 DOI: 10.1016/j.mri.2010.03.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 02/24/2010] [Accepted: 03/05/2010] [Indexed: 11/18/2022]
Abstract
Randomized, placebo-controlled single blinded study was carried out to evaluate the effect of oral creatine supplementation on cellular energetics, manual muscle test (MMT) score and functional status in steroid-naive, ambulatory boys suffering with Duchenne muscular dystrophy (DMD; n=33). Eighteen patients received creatine monohydrate (Cr; 5 g/day for 8 weeks), while 15 received placebo (500 mg of vitamin C). Phosphorus metabolite ratios were determined from the right calf muscle of patients using phosphorus magnetic resonance spectroscopy ((31)P MRS) both prior to (baseline) and after supplementation of Cr or placebo. In addition, metabolite ratios were determined in normal calf muscle of age and sex matched controls (n=8). Significant differences in several metabolite ratios were observed between controls and DMD patients indicating a lower energy state in these patients. Analysis using analysis of covariance adjusted for age and stature showed that the mean phosphocreatine (PCr)/inorganic phosphate (Pi) ratio in patients treated with Cr (4.7; 95% CI; 3.9-5.6) was significantly higher (P=.03) compared to the placebo group (3.3; 95% CI; 2.5-4.2). The mean percentage increase in PCr/Pi ratio was also more in patients <7 years of age compared to older patients after Cr supplementation indicating variation in therapeutic effect with the age. In the placebo group, significant reduction in PCr/Pi (P=.0009), PCr/t-ATP (P=.05) and an increase in phosphodiester (PDE)/PCr ratios was observed after supplementation. Further, in the placebo group, patients <7 years showed reduction of PCr/t-ATP and Pi/t-ATP compared to older patients (>7 years), after supplementation. These results imply that the significant difference observed in PCr/Pi ratio between the Cr and the placebo groups after supplementation may be attributed to a decrease of PCr in the placebo group and an increase in PCr in the Cr group. Changes in MMT score between the two groups was significant (P=.04); however, no change in functional scale (P=.19) was observed. Parents reported subjective improvement on Cr supplementation versus worsening in placebo (P=.02). Our results indicated that Cr was well tolerated and oral Cr significantly improved the muscle PCr/Pi ratio and preserved the muscle strength in short term. However, this study provides no evidence that creatine will prove beneficial after long-term treatment, or have any positive effect on patient lifespan.
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Affiliation(s)
- Bidisha Banerjee
- Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
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21
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Itagaki K, Menconi M, Antoniu B, Zhang Q, Gonnella P, Soybel D, Hauser C, Hasselgren PO. Dexamethasone stimulates store-operated calcium entry and protein degradation in cultured L6 myotubes through a phospholipase A(2)-dependent mechanism. Am J Physiol Cell Physiol 2010; 298:C1127-39. [PMID: 20107037 DOI: 10.1152/ajpcell.00309.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Muscle wasting in various catabolic conditions is at least in part regulated by glucocorticoids. Increased calcium levels have been reported in atrophying muscle. Mechanisms regulating calcium homeostasis in muscle wasting, in particular the role of glucocorticoids, are poorly understood. Here we tested the hypothesis that glucocorticoids increase intracellular calcium concentrations in skeletal muscle and stimulate store-operated calcium entry (SOCE) and that these effects of glucocorticoids may at least in part be responsible for glucocorticoid-induced protein degradation. Treatment of cultured myotubes with dexamethasone, a frequently used in vitro model of muscle wasting, resulted in increased intracellular calcium concentrations determined by fura-2 AM fluorescence measurements. When SOCE was measured by using calcium "add-back" to muscle cells after depletion of intracellular calcium stores, results showed that SOCE was increased 15-25% by dexamethasone and that this response to dexamethasone was inhibited by the store-operated calcium channel blocker BTP2. Dexamethasone treatment stimulated the activity of calcium-independent phospholipase A(2) (iPLA(2)), and dexamethasone-induced increase in SOCE was reduced by the iPLA(2) inhibitor bromoenol lactone (BEL). In additional experiments, treatment of myotubes with the store-operated calcium channel inhibitor gadolinium ion or BEL reduced dexamethasone-induced increase in protein degradation. Taken together, the results suggest that glucocorticoids increase calcium concentrations in myocytes and stimulate iPLA(2)-dependent SOCE and that glucocorticoid-induced muscle protein degradation may at least in part be regulated by increased iPLA(2) activity, SOCE, and cellular calcium levels.
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Affiliation(s)
- Kiyoshi Itagaki
- Dept. of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Interaction of hydrocortisone with ATP and adenosine on nerve-mediated contractions of frog skeletal muscle. Eur J Pharmacol 2009; 607:54-9. [PMID: 19239911 DOI: 10.1016/j.ejphar.2009.02.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 02/10/2009] [Indexed: 11/24/2022]
Abstract
The inhibitory effects of ATP and adenosine on the nerve-mediated contractile responses of isolated sartorius muscle of the frog, Rana ridibunda, evoked by electrical field stimulation (EFS) were studied using pharmacological organ-bath technique. The effects of hydrocortisone applied in vitro and in vivo on contractility of sartorius muscle were also examined. ATP (100 microM) significantly reduced the amplitude of contraction to EFS of sartorius muscle, while pyridoxalphosphate-6-azonphenyl-2',4'-disulfonic acid (PPADS; 10 microM), a P2 receptor antagonist, abolished inhibitory effect of ATP. A similar inhibitory effect of adenosine (100 microM) was fully antagonized by 8-(p-sulfophenyl)-theophylline (8-SPT, 100 microM), a P1 receptor antagonist. Incubation of the tissue with hydrocortisone (10 microM) caused a slight, but significant, decrease of muscle contractions. After incubation of muscle preparations with both hydrocortisone and ATP, no inhibition of muscle contractility was registered. A single injection of hydrocortisone (100 mg/kg) 12 h prior to experiments to frogs did not significantly change the nerve-mediated contractility of isolated sartorius muscle; however, it abolished the inhibitory action of ATP without changing inhibitory activity of adenosine. After treatment of frogs with hydrocortisone for 14 days (100 mg/kg/day), both ATP and adenosine retained their inhibitory action on EFS-induced contractions of the muscle, and their effects were antagonized by PPADS and 8-SPT, respectively. It is concluded that hydrocortisone has antagonistic actions against the inhibitory effects of ATP at the frog neuromuscular junction, although this effect is lost following long-term treatment with hydrocortisone.
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Prior sprint cycling did not enhance training adaptation, but resting salivary hormones were related to workout power and strength. Eur J Appl Physiol 2009; 105:919-27. [DOI: 10.1007/s00421-008-0978-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2008] [Indexed: 10/21/2022]
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24
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Mavrogeni S, Papavasiliou A, Douskou M, Kolovou G, Papadopoulou E, Cokkinos DV. Effect of deflazacort on cardiac and sternocleidomastoid muscles in Duchenne muscular dystrophy: a magnetic resonance imaging study. Eur J Paediatr Neurol 2009; 13:34-40. [PMID: 18406648 DOI: 10.1016/j.ejpn.2008.02.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 11/04/2007] [Accepted: 02/11/2008] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To evaluate the involvement of cardiac and sternocleidomastoid muscles by magnetic resonance imaging (MRI) measurement of T2 relaxation time and the left ventricular systolic function in patients with Duchenne muscular dystrophy (DMD) on treatment with deflazacort and compare them with DMD patients without treatment. SUBJECTS Seventeen patients with DMD (aged 17-22 years) on treatment with deflazacort for at least 7 years and 17 boys with DMD of younger age (12-15 years) without steroid treatment. All patients were free of cardiac or respiratory symptoms and had normal ECG and Holter monitor examination. METHODS T2 relaxation time of the myocardium (H), left (SCM-L) and right sternocleidomastoid (SCM-R) muscles and left ventricular systolic function were evaluated by magnetic resonance imaging (MRI) in two groups of DMD patients. Myocardial and sternocleidomastoid muscles T2 relaxation time was calculated using 16 TEs (10-85 msec) and TR at least 2000 ms and T2 maps were created. RESULTS DMD on deflazacort had higher T2 relaxation time values of the heart and of both sternocleidomastoid muscles (T2H median (range): 47 (41-48) vs. 33 (31-37)ms, p<0.001, T2 SCM-L median (range): 35 (30-37) vs. 23 (20-26)ms, p<0.001, T2 SCM-R median (range): 35 (32-37) vs. 23 (20-27)ms, p<0.001) and left ventricular systolic function (LVEDV median (range): 95 (75-120) vs. 90 (80-105)ml, p=0.03, LVESV median (range): 45 (38-55) vs. 47 (41-51)ml, p=0.81(NS), LVEF median (range): 53% (51-57) vs. 48% (42-51), p<0.001) compared to DMD without treatment. CONCLUSIONS DMD patients on deflazacort are characterized by better preservation of the T2 relaxation time of myocardium and sternocleidomastoid muscles and better LV systolic function. The duration of this beneficial effect needs to be studied prospectively.
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Affiliation(s)
- Sophie Mavrogeni
- Onassis Cardiac Surgery Center, Pendeli Children's Hospital, Athens, Greece.
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Haller J, Mikics E, Makara GB. The effects of non-genomic glucocorticoid mechanisms on bodily functions and the central neural system. A critical evaluation of findings. Front Neuroendocrinol 2008; 29:273-91. [PMID: 18054070 DOI: 10.1016/j.yfrne.2007.10.004] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 10/02/2007] [Accepted: 10/17/2007] [Indexed: 11/15/2022]
Abstract
Mounting evidence suggests that--beyond the well-known genomic effects--glucocorticoids affect cell function via non-genomic mechanisms. Such mechanisms operate in many major systems and organs including the cardiovascular, immune, endocrine and nervous systems, smooth and skeletal muscles, liver, and fat cells. Non-genomic effects are exerted by direct actions on membrane lipids (affecting membrane fluidity), membrane proteins (e.g. ion channels and neurotransmitter receptors), and cytoplasmic proteins (e.g. MAPKs, phospholipases, protein kinases, etc.). These actions are mediated by the glucocorticoids per se or by the proteins dissociated from the liganded glucocorticoid receptor complex. The MR and GR also activate non-genomic mechanisms in certain cases. Some effects of glucocorticoids are shared by a variety of steroids, whereas others are more selective. Moreover, "ultra-selective" effects-mediated by certain glucocorticoids only-were also shown. Disparate findings suggest that non-genomic mechanisms also show "demand-specificity", i.e. require the coincidence of two or more processes. Some of the non-genomic mechanisms activated by glucocorticoids are therapeutically relevant; moreover, the "non-genomic specificity" of certain glucocorticoids raises the possibility of therapeutic applications. Despite the large body of evidence, however, the non-genomic mechanisms of glucocorticoids are still poorly understood. Criteria for differentiating genomic and non-genomic mechanisms are often loosely applied; interactions between various mechanisms are unknown, and non-genomic mechanism-specific pharmacological (potentially therapeutic) agents are lacking. Nevertheless, the discovery of non-genomic mechanisms is a major breakthrough in stress research, and further insights into these mechanisms may open novel approaches for the therapy of various diseases.
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Affiliation(s)
- József Haller
- Department of Behavioral Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
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Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy of childhood. This incurable disease is characterised by muscle wasting and loss of walking ability leading to complete wheelchair dependence by 13 years of age. Prolongation of walking is one of the major aims of treatment. OBJECTIVES The aim of this review was to assess whether glucocorticoid corticosteroids stabilize or improve muscle strength and walking in boys with DMD. SEARCH STRATEGY This is an update of the Cochrane systematic review first published in 2004 (Manzur 2004). We searched the Cochrane Neuromuscular Disease Group Trials Register (August 2006) using the term 'Duchenne muscular dystrophy'. We also searched MEDLINE (January 1966 to July 2007), EMBASE (January 1980 to August 2006), CINAHL and LILACS (January 1982 to August 2006). We wrote to authors of published studies and other experts in this disease to help identify other trials, checked the references in the identified trials and hand searched the abstracts of relevant journals. SELECTION CRITERIA Types of studies: randomised or quasi-randomised trials. TYPES OF PARTICIPANTS all patients with a definite diagnosis of Duchenne muscular dystrophy. Types of interventions: glucocorticoids such as prednisone, prednisolone, deflazacort or others, with a minimum treatment period of three months. PRIMARY OUTCOME MEASURE prolongation of walking (independent walking without long leg calipers). SECONDARY OUTCOME MEASURES strength outcome measures, manual muscle strength testing using Medical Research Council strength scores, functional outcome measures and adverse events. DATA COLLECTION AND ANALYSIS We identified six randomised controlled trials that met the inclusion criteria for our review, and one of these (Beenakker 2005) is a new addition to this update, as it was published subsequent to our first review (Manzur 2004). Two review authors independently selected the trials for the review and assessed methodological quality. Data extraction and inputting were double-checked. PRIMARY OUTCOME MEASURE data from one small study used prolongation of walking as an outcome measure and did not show significant benefit. SECONDARY OUTCOME MEASURES The meta-analysis of the results from four randomised controlled trials with altogether 249 participants showed that glucocorticoid corticosteroids improved muscle strength and function over six months. Improvements were seen in time taken to rise from the floor (Gowers' time), nine metres walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity. One randomised controlled trial with altogether 28 participants showed that glucocorticoid corticosteroids stabilize muscle strength and function for up to two years. The most effective prednisolone regime appears to be 0.75 mg/kg/day, given in a daily dose regime. Not enough data were available to compare efficacy of prednisone with deflazacort. Adverse effects: Excessive weight gain, behavioural abnormalities, cushingoid appearance and excessive hair growth were all more common with glucocorticoid corticosteroids than placebo. Long-term adverse effects of glucocorticoid therapy could not be evaluated because of the short-term duration of the randomised studies.Non-randomised studies: A number of non-randomised studies with important efficacy and adverse effects data are tabulated and discussed. AUTHORS' CONCLUSIONS There is evidence from randomised controlled studies that glucocorticoid corticosteroid therapy in Duchenne muscular dystrophy improves muscle strength and function in the short-term (six months to two years). The most effective prednisolone regime appears to be 0.75 mg/kg/day, given daily. In the short term, adverse effects were significantly more common but not clinically severe. Long-term benefits and hazards of glucocorticoid treatment cannot be evaluated from the currently published randomised studies. Non-randomised studies support the conclusions of functional benefits but also identify clinically significant adverse effects of long-term treatment. These benefits and adverse effects have implications for future research studies and clinical practice.
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Affiliation(s)
- A Y Manzur
- Hammersmith Hospital, Dubowitz Neuromuscular Centre, Department of Paediatrics, DuCane Road, London, UK, W12 OHS.
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Hasselgren PO, Menconi MJ, Fareed MU, Yang H, Wei W, Evenson A. Novel aspects on the regulation of muscle wasting in sepsis. Int J Biochem Cell Biol 2005; 37:2156-68. [PMID: 16125115 DOI: 10.1016/j.biocel.2005.01.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 11/17/2004] [Accepted: 01/07/2005] [Indexed: 12/18/2022]
Abstract
Muscle wasting in sepsis is associated with increased expression of messenger RNA for several genes in the ubiquitin-proteasome proteolytic pathway, indicating that increased gene transcription is involved in the development of muscle atrophy. Here we review the influence of sepsis on the expression and activity of the transcription factors activator protein-1, nuclear factor-kappaB (NF-kappaB), and CCAAT/enhancer binding protein, as well as the nuclear cofactor p300. These transcription factors may be important for sepsis-induced muscle wasting because several of the genes in the ubiquitin-proteasome proteolytic pathway have multiple binding sites for activating protein-1, nuclear factor-kappaB, and CCAAT/enhancer binding protein in their promoter regions. In addition, the potential role of increased muscle calcium levels for sepsis-induced muscle atrophy is reviewed. Calcium may regulate several mechanisms and factors involved in muscle wasting, including the expression and activity of the calpain-calpastatin system, proteasome activity, CCAAT/enhancer binding protein transcription factors, apoptosis and glucocorticoid-mediated muscle protein breakdown. Because muscle wasting is commonly seen in patients with sepsis and has severe clinical consequences, a better understanding of mechanisms regulating sepsis-induced muscle wasting may help improve the care of patients with sepsis and other muscle-wasting conditions as well.
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Affiliation(s)
- Per-Olof Hasselgren
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
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28
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Liu JMK, Okamura CS, Bogan DJ, Bogan JR, Childers MK, Kornegay JN. Effects of prednisone in canine muscular dystrophy. Muscle Nerve 2005; 30:767-73. [PMID: 15468337 DOI: 10.1002/mus.20154] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Glucocorticoid use may provide short-term functional improvement in boys with Duchenne muscular dystrophy (DMD). We report functional and histopathologic changes following a 4-month course of daily oral prednisone in a canine model of DMD, termed golden retriever muscular dystrophy (GRMD). Muscle extension forces in GRMD dogs treated daily with 1 and 2 mg/kg prednisone measured 2.349 +/- 0.92 and 3.486 +/- 0.67 N/kg, respectively, compared to 1.927 +/- 0.63 N/kg in untreated GRMD controls (p < 0.05 for 2 mg/kg group); GRMD muscle flexion forces measured 0.435 +/- 0.13 and 0.303 +/- 0.08 N/kg, respectively, compared to 0.527 +/- 0.01 N/kg in untreated GRMD controls (p < 0.05 for both groups). Although cranial sartorius hypertrophy and tibiotarsal joint angles also tended to improve, myofiber calcification increased and fetal myosin expression decreased following prednisone. Thus, functional data indicate benefit but histopathologic changes following prednisone treatment in GRMD suggest possible deleterious consequences.
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Affiliation(s)
- Jocelyn M K Liu
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, Missouri, USA
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29
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Basset O, Boittin FX, Dorchies OM, Chatton JY, van Breemen C, Ruegg UT. Involvement of Inositol 1,4,5-Trisphosphate in Nicotinic Calcium Responses in Dystrophic Myotubes Assessed by Near-plasma Membrane Calcium Measurement. J Biol Chem 2004; 279:47092-100. [PMID: 15322099 DOI: 10.1074/jbc.m405054200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In skeletal muscle cells, plasma membrane depolarization causes a rapid calcium release from the sarcoplasmic reticulum through ryanodine receptors triggering contraction. In Duchenne muscular dystrophy (DMD), a lethal disease that is caused by the lack of the cytoskeletal protein dystrophin, the cytosolic calcium concentration is known to be increased, and this increase may lead to cell necrosis. Here, we used myotubes derived from control and mdx mice, the murine model of DMD, to study the calcium responses induced by nicotinic acetylcholine receptor stimulation. The photoprotein aequorin was expressed in the cytosol or targeted to the plasma membrane as a fusion protein with the synaptosome-associated protein SNAP-25, thus allowing calcium measurements in a restricted area localized just below the plasma membrane. The carbachol-induced calcium responses were 4.5 times bigger in dystrophic myotubes than in control myotubes. Moreover, in dystrophic myotubes the carbachol-mediated calcium responses measured in the subsarcolemmal area were at least 10 times bigger than in the bulk cytosol. The initial calcium responses were due to calcium influx into the cells followed by a fast refilling/release phase from the sarcoplasmic reticulum. In addition and unexpectedly, the inositol 1,4,5-trisphosphate receptor pathway was involved in these calcium signals only in the dystrophic myotubes. This surprising involvement of this calcium release channel in the excitation-contraction coupling could open new ways for understanding exercise-induced calcium increases and downstream muscle degeneration in mdx mice and, therefore, in DMD.
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Affiliation(s)
- Olivier Basset
- Pharmacology Laboratory, School of Pharmacy, University of Lausanne-Geneva, 1211 Geneva, Switzerland
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30
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Barbato JC, Rashid S, Mulrow PJ, Shapiro JI, Franco-Saenz R. Mechanisms for aldosterone and spironolactone-induced positive inotropic actions in the rat heart. Hypertension 2004; 44:751-7. [PMID: 15466666 DOI: 10.1161/01.hyp.0000144466.11568.7e] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previously, we reported that aldosterone and spironolactone have inotropic effects in the isolated perfused heart. To address the mechanisms underlying these inotropic effects, we examined the effects of aldosterone and spironolactone on isolated cardiac myocyte shortening, intracellular calcium ([Ca+2]i), pHi, and calcium-dependent actinomyosin ATPase activity. Aldosterone significantly increased shortening in cardiac myocytes (8.0+/-1.0 versus 16.0+/-1.3%, P<0.01) but neither diastolic [Ca+2]i (61.0+/-1.1 versus 66.0+/-4.4 nmol/L) nor peak systolic [Ca+2]i (302+/-11 versus 304+/-17 nmol/L) was affected. Spironolactone-increased shortening was also not coupled with changes in peak systolic calcium; however, diastolic calcium was significantly increased by spironolactone. Aldosterone, but not spironolactone, increased pHi from 7.23+/-0.03 to 7.59+/-0.02 (P<0.01); this was completely blocked by coadministration of 100 micromol/L of ethyl-isopropyl amiloride (EIPA), an inhibitor of the Na+/H+ exchanger (P<0.01). Consistent with this finding, aldosterone increased cytosolic sodium concentration ([Na+]i) from 9.2+/-0.15 to 11.4+/-0.2 mmol/L and produced a leftward shift in the pCa ATPase curve (pCa=5.82+/-0.02 versus 6.35+/-0.02, P<0.01) without affecting maximal myosin ATPase activity. Conversely, spironolactone, but not aldosterone, significantly increases maximal actomyosin ATPase activity (837+/-59 versus 355+/-52 nmol inorganic phosphate (P(i)) x min(-1) x g tissue(-1)). Collectively, these data strongly suggest that the inotropic actions of aldosterone and spironolactone are caused by different mechanisms of action. Aldosterone appeared to increase inotropy primarily through increased cytosolic pH, whereas spironolactone increased myosin ATPase calcium sensitivity and diastolic calcium concentration.
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Affiliation(s)
- John C Barbato
- Department of Medicine, Medical College of Ohio, Toledo, OH 43614, USA
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31
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Gaud A, Simon JM, Witzel T, Carre-Pierrat M, Wermuth CG, Ségalat L. Prednisone reduces muscle degeneration in dystrophin-deficient Caenorhabditis elegans. Neuromuscul Disord 2004; 14:365-70. [PMID: 15145337 DOI: 10.1016/j.nmd.2004.02.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Revised: 02/12/2004] [Accepted: 02/20/2004] [Indexed: 11/24/2022]
Abstract
Duchenne muscular dystrophy is a degenerative muscular disease caused by mutations in the dystrophin gene. There is no curative treatment against Duchenne muscular dystrophy. In several countries, the steroid prednisone (or analogs) is prescribed as a palliative treatment. In the model animal Caenorhabditis elegans, mutations of the dys-1 dystrophin-like gene lead to a muscular degenerative phenotype when they are associated with a mild MyoD mutation. This cheap and fast-growing model of dystrophinopathy may be used to screen for molecules able to slow muscle degeneration. In a blind screen of approximately 100 compounds covering a wide spectrum of targets, we found that prednisone is beneficial to the C. elegans dystrophin-deficient muscles. Prednisone reduces by 40% the number of degenerating cells in this animal. This result is a proof-of-principle for the use of C. elegans as a tool in the search for molecules active against the effects of dystrophin-deficiency. Moreover, since C. elegans is not susceptible to inflammation, this suggests that prednisone exerts a direct effect on muscle survival.
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Affiliation(s)
- Aurélie Gaud
- CGMC, CNRS-UMR 5534, Université Lyon1, 43 bld du 11 Novembre, 69622 Villeurbanne cedex, France
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32
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Abstract
BACKGROUND Duchenne muscular dystrophy is the most common muscular dystrophy of childhood. This incurable disease is characterised by muscle wasting and loss of walking ability leading to complete wheelchair dependence by 13 years of age. Prolongation of walking is one of the major aims of treatment. OBJECTIVES The aim of this review was to assess whether glucocorticoid corticosteroids stabilize or improve muscle strength and walking in boys with DMD. SEARCH STRATEGY We searched the Cochrane Neuromuscular Disease Group specialised register (October 2003) using the term 'Duchenne muscular dystrophy'. We also searched MEDLINE (January 1966 to October 2003), EMBASE (January 1980 to October 2003), CINAHL and LILACS (January 1982 to October 2003). We wrote to authors of published studies and other experts in this disease to help identify other trials, checked the references in the identified trials and handsearched the abstracts of relevant journals. SELECTION CRITERIA Types of studies: randomised or quasi-randomised trials. TYPES OF PARTICIPANTS all patients with a definite diagnosis of Duchenne muscular dystrophy. Types of interventions: glucocorticoids such as prednisone, prednisolone, deflazacort or others, with a minimum treatment period of three months. PRIMARY OUTCOME MEASURE prolongation of walking (independent walking without long leg calipers). SECONDARY OUTCOME MEASURES strength outcome measures, manual muscle strength testing using Medical Research Council strength scores, functional outcome measures and adverse events. DATA COLLECTION AND ANALYSIS We identified five randomised controlled trials that met the inclusion criteria for our review. Two reviewers independently selected the trials for the review and assessed methodological quality. Data extraction and inputting were double-checked. PRIMARY OUTCOME MEASURE data from one small study used prolongation of walking as an outcome measure and did not show significant benefit. SECONDARY OUTCOME MEASURES The meta-analysis of the results from three randomised controlled trials showed that glucocorticoid corticosteroids improved muscle strength and function over six months. Improvements were seen in time taken to rise from the floor (Gowers' time), nine metres walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity. One randomised controlled trial showed that glucocorticoid corticosteroids stabilize muscle strength and function for up to two years. The most effective prednisolone regime appears to be 0.75 mg/kg/day. Not enough data were available to compare efficacy of prednisone with deflazacort.Adverse effects: Excessive weight gain, behavioural abnormalities, cushingoid appearance and excessive hair growth were all more common with glucocorticoid corticosteroids than placebo. Long-term adverse effects of glucocorticoid therapy could not be evaluated because of the short-term duration of the randomised studies.Non-randomised studies: a number of non-randomised studies with important efficacy and adverse effects data are tabulated and discussed. REVIEWERS' CONCLUSIONS There is evidence from randomised controlled studies that glucocorticoid corticosteroid therapy in Duchenne muscular dystrophy improves muscle strength and function in the short-term (six months to two years). The most effective prednisolone regime appears to be 0.75 mg/kg/day. In the short term, adverse effects were significantly more common but not clinically severe. Long-term benefits and hazards of glucocorticoid treatment cannot be evaluated from the currently published randomised studies. Non-randomised studies support the conclusions of functional benefits but also indicate clinically significant adverse effects of long-term treatment. These benefits and adverse effects have implications for future research studies and clinical practice.
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Affiliation(s)
- A Y Manzur
- Dubowitz Neuromuscular Centre, Department of Paediatrics, Hammersmith Hospital, DuCane Road, London, UK, W12 OHS
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33
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De Luca A, Pierno S, Liantonio A, Cetrone M, Camerino C, Fraysse B, Mirabella M, Servidei S, Rüegg UT, Conte Camerino D. Enhanced dystrophic progression in mdx mice by exercise and beneficial effects of taurine and insulin-like growth factor-1. J Pharmacol Exp Ther 2003; 304:453-63. [PMID: 12490622 DOI: 10.1124/jpet.102.041343] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A preclinical screening for prompt-to-use drugs that are safer than steroids and beneficial in Duchenne muscular dystrophy was performed. Compounds able to reduce calcium-induced degeneration (taurine or creatine 10% in chow) or to stimulate regeneration [insulin-like growth factor-1 (IGF-1); 50 or 500 microg/kg s.c.] were administered for 4 to 8 weeks to mdx mice undergoing chronic exercise on a treadmill, a protocol to worsen dystrophy progression. alpha-Methyl-prednisolone (PDN; 1 mg/kg) was used as positive control. The effects were evaluated in vivo on forelimb strength and in vitro electrophysiologically on the macroscopic chloride conductance (gCl), an index of degeneration-regeneration events in mdx muscles, and on the mechanical threshold, a calcium-sensitive index of excitation-contraction coupling. The exercise produced a significant weakness and an impairment of gCl, by further decreasing the already low value of degenerating diaphragm (DIA) and fully hampering the increase of gCl typical of regenerating extensor digitorum longus (EDL) mdx muscle. The already negative voltage threshold for contraction of mdx EDL was also slightly worsened. Taurine > creatine > IGF-1 counteracted the exercise-induced weakness. The amelioration of gCl was drug- and muscle-specific: taurine was effective in EDL, but not in DIA muscle; IGF-1 and PDN were fully restorative in both muscles, whereas creatine was ineffective. An acute effect of IGF-1 on gCl was observed in vitro in untreated, but not in IGF-1-treated exercised mdx muscles. Taurine > PDN > IGF-1, but not creatine, significantly ameliorated the negative threshold voltage values of the EDL fibers. The results predict a potential benefit of taurine and IGF-1 for treating human dystrophy.
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MESH Headings
- Animals
- Creatine/therapeutic use
- Disease Progression
- Electrophysiology
- Insulin-Like Growth Factor I/therapeutic use
- Ion Channels/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Muscle Contraction/physiology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Skeletal/physiology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiology
- Muscular Dystrophy, Animal/drug therapy
- Muscular Dystrophy, Animal/pathology
- Muscular Dystrophy, Animal/therapy
- Patch-Clamp Techniques
- Physical Conditioning, Animal/physiology
- Taurine/therapeutic use
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Affiliation(s)
- Annamaria De Luca
- Department of Pharmacobiology, Unit of Pharmacology, University of Bari, Bari, Italy.
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Urbach V, Walsh DE, Mainprice B, Bousquet J, Harvey BJ. Rapid non-genomic inhibition of ATP-induced Cl- secretion by dexamethasone in human bronchial epithelium. J Physiol 2002; 545:869-78. [PMID: 12482892 PMCID: PMC2290723 DOI: 10.1113/jphysiol.2002.028183] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A non-genomic antisecretory role for dexamethasone at low concentrations (0.1 nM to1 microM) is described in monolayers of human bronchial epithelial cells in primary culture and in a continuous cell line (16HBE14o- cells). Dexamethasone produced a rapid decrease of [Ca(2+)](i) (measured with fura-2 spectrofluorescence) to a new steady-state concentration. After 15 min exposure to dexamethasone (1 nM), [Ca(2+)](i) was reduced by 32 +/- 11 nM (n = 7, P < 0.0001) from a basal value of 213 +/- 36 nM (n = 7). We have shown previously that aldosterone (1 nM) also produces a rapid fall in [Ca(2+)](i); however, after the decrease in [Ca(2+)](i) induced by dexamethasone, subsequent addition of aldosterone did not produced any further lowering of [Ca(2+)](i). The rapid response to dexamethasone was insensitive to pretreatment with cycloheximide and unaffected by the glucocorticoid type II and mineralocorticoid receptor antagonists RU486 and spironolactone, respectively. The rapid [Ca(2+)](i) decrease induced by dexamethasone was inhibited by the Ca(2+)-ATPase pump inhibitor thapsigargin (1 microM), the adenylate cyclase inhibitor MDL hydrochloride (500 microM) and the protein kinase A inhibitor Rp-adenosine 3',5'-cyclic monophosphorothioate (200 microM), but was not affected by the protein kinase C inhibitor, chelerythrine chloride (0.1 microM). Treatment of 16HBE14o- cell monolayers with dexamethasone (1 nM) inhibited the large and transient [Ca(2+)](i) increase induced by apical exposure to ATP (10(-4) M). Dexamethasone (1 nM) also reduced by 30 % the Ca(2+)-dependant Cl(-) secretion induced by apical exposure to ATP (measured as the Cl(-)-sensitive short-circuit current across monolayers mounted in Ussing chambers). Our results demonstrate, for the first time, that dexamethasone at low concentrations inhibits Cl(-) secretion in human bronchial epithelial cells. The rapid inhibition of Cl(-) secretion induced by the synthetic glucocorticoid is associated with a rapid decrease in [Ca(2+)](i) via a non-genomic mechanism that does not involve the classical glucocorticoid or mineralocorticoid receptor. Rather, it is a result of rapid non-genomic stimulation of thapsigargin-sensitive Ca(2+)-ATPase, via adenylate cyclase and protein kinase A signalling.
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Affiliation(s)
- V Urbach
- INSERM U454, CHU A. de Villeneuve, 34295 Montpellier Cedex 05, France.
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35
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Rogers KM, Bonar CA, Estrella JL, Yang S. Inhibitory effect of glucocorticoid on coronary artery endothelial function. Am J Physiol Heart Circ Physiol 2002; 283:H1922-8. [PMID: 12384470 DOI: 10.1152/ajpheart.00364.2002] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute and chronic stresses are implicated in cardiovascular diseases including coronary artery disease. The present study was designed to examine the direct effects of the stress hormone cortisol on nitric oxide (NO) release and endothelial NO synthase (eNOS) expression in cultured bovine coronary artery endothelial cells (BCAEC). Nitrate, nitrite, and NO (NO(x)) were measured by the chemiluminescence method. At 24 h after treatment, cortisol (1 nM-10 microM) produced a dose-dependent decrease in NO(x) release, which was attenuated in the presence of the 11beta-hydroxysteroid dehydrogenase inhibitor carbenoxolone (3 microM). In accordance, eNOS protein levels were significantly decreased by cortisol in a dose-dependent manner. Cortisol pretreatment significantly increased the rate of eNOS protein degradation in the presence of cycloheximide. In addition, cortisol pretreatment decreased ATP-induced intracellular Ca(2+) elevation and NO(x) release in BCAEC. The presence of glucocorticoid receptors in BCAEC was demonstrated by Western blot. The results suggest that cortisol, through activation of glucocorticoid receptors, suppresses NO(x) release in BCAEC by downregulating eNOS proteins and inhibiting intracellular Ca(2+) mobilization. Decreased NO(x) is likely to result in an increase in contraction of coronary arteries, leading to a decrease in coronary blood flow.
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Affiliation(s)
- Kestrel M Rogers
- Department of Chemistry, California State University, San Bernardino, CA 92407, USA
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36
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Ruegg UT, Nicolas-Métral V, Challet C, Bernard-Hélary K, Dorchies OM, Wagner S, Buetler TM. Pharmacological control of cellular calcium handling in dystrophic skeletal muscle. Neuromuscul Disord 2002; 12 Suppl 1:S155-61. [PMID: 12206810 DOI: 10.1016/s0960-8966(02)00095-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Duchenne muscular dystrophy arises due to the lack of the cytoskeletal protein dystrophin. In Duchenne muscular dystrophy muscle, the lack of dystrophin is accompanied by alterations in the dystrophin-glycoprotein complex. We and others have found that the absence of dystrophin in cells of the Duchenne muscular dystrophy animal model, the mdx mouse, leads to elevated Ca(2+) influx and cytosolic Ca(2+) concentrations when exposed to stress. We have also shown that alpha-methylprednisolone, the only drug used successfully in the therapy of Duchenne muscular dystrophy, and creatine lowered cytosolic Ca(2+) levels in mdx myotubes. It is likely that chronic elevation of [Ca(2+)] in the cytosol in response to stress is an initiating event for apoptosis and/or necrosis in Duchenne muscular dystrophy or mdx muscle and that alterations in mitochondrial function and metabolism are involved. Other cellular signalling pathways (e.g. nitric oxide) might also be affected.
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Affiliation(s)
- Urs T Ruegg
- Pharmacology Group, School of Pharmacy, University of Lausanne/BEP, CH-1015 Lausanne, Switzerland.
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37
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Courdier-Fruh I, Barman L, Briguet A, Meier T. Glucocorticoid-mediated regulation of utrophin levels in human muscle fibers. Neuromuscul Disord 2002; 12 Suppl 1:S95-104. [PMID: 12206803 DOI: 10.1016/s0960-8966(02)00089-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies on transgenic mice indicate that upregulation of utrophin protein may offer a potential treatment strategy for Duchenne muscular dystrophy. We have analyzed the effect of the glucocorticoid 6alpha-methylprednisolone-21 sodium succinate on utrophin protein levels, using a cell-based assay with differentiated human myotubes, derived from biopsies of healthy individuals or Duchenne muscular dystrophy patients. We found that within 5-7 days 6alpha-methylprednisolone-21 sodium succinate increases utrophin protein up to approximately 40% in both normal and dystrophin-deficient myotubes compared to untreated control cultures. When analyzed in promoter-reporter assays 6alpha-methylprednisolone-21 sodium succinate activated a utrophin promoter A-fragment but did not activate a utrophin promoter B-fragment. Surprisingly, endogenous levels of utrophin mRNA in 6alpha-methylprednisolone-21 sodium succinate-treated muscle cells were unaltered indicating that the utrophin-inducing effect of glucocorticoids may be a result of post-transcriptional mechanisms. We have also analyzed 66 glucocorticoids for their effect on utrophin protein levels and found that glucocorticoids in general are able to induce utrophin protein in human myotubes.
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Affiliation(s)
- Isabelle Courdier-Fruh
- MyoContract Pharmaceutical Research Ltd., Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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38
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Barbato JC, Mulrow PJ, Shapiro JI, Franco-Saenz R. Rapid effects of aldosterone and spironolactone in the isolated working rat heart. Hypertension 2002; 40:130-5. [PMID: 12154102 DOI: 10.1161/01.hyp.0000025879.29822.24] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic administration of aldosterone promotes myocardial fibrosis in rats. The Randomized Aldactone Evaluation Study reported that the aldosterone antagonist spironolactone improved outcome in patients with congestive heart failure, suggesting a deleterious effect of aldosterone in the heart. Aldosterone has been shown to have rapid nongenomic effects in different tissues including the heart. However, the hemodynamic actions of aldosterone and spironolactone are not well characterized. In this study, we examined the hemodynamic effects of aldosterone and its receptor antagonist, spironolactone, in the isolated rat heart by use of the Langendorff-Neely technique. Perfusion with 10 nmol/L aldosterone increased contractility by 45% within 2 to 4 minutes (P<0.01). Similar to the aldosterone effect, 10 nmol/L spironolactone increased contractility by 41% (P<0.01). Furthermore, 100-fold molar excess of spironolactone did not block the aldosterone effect. Perfusion of aldosterone plus spironolactone resulted in the highest increase in contractility 106% (P<0.01). The threshold response for aldosterone occurred within physiological concentrations (0.5 to 1 nmol/L), and maximal contractility was achieved with 10 nmol/L aldosterone. For spironolactone, the threshold and maximal contractile responses occurred at concentrations readily achieved with clinical dosing, 0.1 to 0.5 nmol/L and 1.0 nmol/L, respectively. These data demonstrate that aldosterone and spironolactone have rapid, positive inotropic actions on the myocardium. Moreover, addition of spironolactone to aldosterone increased contractility beyond the maximal responses elicited by each agent when perfused alone, thus suggesting different pathways of action. Furthermore, the intrinsic inotropic effects of spironolactone might be relevant to the apparent beneficial effect this compound has in patients with congestive heart failure.
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Affiliation(s)
- John C Barbato
- Department of Medicine, Medical College of Ohio, Toledo 43614-5804, USA
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39
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Buetler TM, Renard M, Offord EA, Schneider H, Ruegg UT. Green tea extract decreases muscle necrosis in mdx mice and protects against reactive oxygen species. Am J Clin Nutr 2002; 75:749-53. [PMID: 11916763 DOI: 10.1093/ajcn/75.4.749] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Duchenne muscular dystrophy is a severe X-linked congenital disorder characterized by lethal muscle wasting caused by the absence of the structural protein dystrophin. OBJECTIVE Because generation of reactive oxygen species appears to play an important role in the pathogenesis of this disease, we tested whether antioxidant green tea extract could diminish muscle necrosis in the mdx mouse dystrophy model. DESIGN A diet supplemented with 0.01% or 0.05% green tea extract was fed to dams and neonates for 4 wk beginning on the day of birth. Muscle necrosis and regeneration were determined in stained cryosections of soleus and elongator digitorum longus muscles. Radical scavenging by green tea extract was determined in differentiated cultured C2C12 cells treated with tert-butylhydroperoxide, with the use of 2',7'-dichlorofluorescin diacetate as a radical detector. RESULTS This feeding regimen significantly and dose-dependently reduced necrosis in the fast-twitch muscle elongator digitorum longus but at the doses tested had no effect on the slow-twitch soleus muscle. Green tea extract concentration-dependently decreased oxidative stress induced by tert-butylhydroperoxide treatment of cultured mouse C2C12 myotubes. The lower effective dose tested in mdx mice corresponds to approximately equal to 1.4 L (7 cups) green tea/d in humans. CONCLUSION Green tea extract may improve muscle health by reducing or delaying necrosis in mdx mice by an antioxidant mechanism.
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Affiliation(s)
- Timo M Buetler
- Pharmacology Group, School of Pharmacy, University of Lausanne, Switzerland
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40
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Abstract
Duchenne muscular dystrophy is the most common and most severe form of childhood muscular dystrophies, resulting in early loss of ambulation between the ages of 7 and 13 years and death in the teens and twenties. Despite the phenomenal advances made in the understanding of the molecular genetics of the disease, no definitive cure has been found. Of all of the therapeutic drugs studied in Duchenne muscular dystrophy, only prednisone seems to have the potential for providing interim functional improvement for boys with Duchenne muscular dystrophy while they wait for a cure with gene or cell therapy. There is still no consensus regarding recommending corticosteroids as standard therapy for boys. This is an evidence-based review of all of the studies of corticosteroids (prednisone, deflazacort, and oxandrolone) in Duchenne muscular dystrophy. From this review, it is clear that until a definitive treatment for Duchenne muscular dystrophy is available, the use of deflazacort and prednisone with judicious dietary control and close clinical monitoring for side effects seems the best intervention for interim preservation of function in such a common devastating disorder of young growing boys.
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Affiliation(s)
- Brenda L Y Wong
- Division of Child Neurology, Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA.
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41
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Passaquin AC, Renard M, Kay L, Challet C, Mokhtarian A, Wallimann T, Ruegg UT. Creatine supplementation reduces skeletal muscle degeneration and enhances mitochondrial function in mdx mice. Neuromuscul Disord 2002; 12:174-82. [PMID: 11738360 DOI: 10.1016/s0960-8966(01)00273-5] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The mdx mouse serves as animal model for Duchenne muscular dystrophy. Energy status in muscles of mdx mice is impaired and we have demonstrated recently that the energy precursor creatine exerts beneficial effects on mdx skeletal muscle cells in culture. Here we show that feeding a creatine-enriched diet to new-born mdx mice strongly reduced the first wave of muscle necrosis four weeks after birth. Necrosis of the fast-twitch muscle extensor digitorum longus was inhibited by 63+/-14% (P<0.0001) while necrosis of the slow-twitch soleus muscle was not significantly decreased. In addition, using chemically skinned muscle fibres, we found that mitochondrial respiration capacity was decreased by about 25% in mdx-derived fibres and that long-term creatine-feeding restored respiration to wild-type levels. These results provide evidence that creatine supplementation in mdx mice improves muscle health and may provide a scientific basis for its use as adjuvant therapy in Duchenne muscular dystrophy.
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Urbach V, Harvey BJ. Rapid and non-genomic reduction of intracellular [Ca(2+)] induced by aldosterone in human bronchial epithelium. J Physiol 2001; 537:267-75. [PMID: 11711579 PMCID: PMC2278946 DOI: 10.1111/j.1469-7793.2001.0267k.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
1. Using a Ca(2+) imaging system and fura-2 AM (5 microM) we showed that exposure of polarised monolayers of human bronchial epithelial cells (16HBE14o- cell line) to aldosterone produced a fast intracellular [Ca(2+)] ([Ca(2+)](i)) decrease, in 70 % of cells. Exposure to aldosterone (1 nM) reduced the [Ca(2+)](i) by 39 +/- 9 nM (n = 282, P < 0.0001) within 10 min, from a basal [Ca(2+)](i) of 131 +/- 19 nM (n = 282). 2. The effect of aldosterone on [Ca(2+)](i) was not affected by inhibitors of the classical genomic pathway, cycloheximide (1 microM) or spironolactone (10 microM). The aldosterone-induced [Ca(2+)](i) decrease was inhibited by thapsigargin (1 microM), pertussis toxin (24 h at 200 ng ml(-1)), the adenylate cyclase inhibitors 2',3'-dideoxyadenosine (200 microM) and MDL-12,330A hydrochloride (500 microM), and the protein kinase A inhibitor R(P)-adenosine 3',5'-cyclic monophosphorothioate (200 microM). In addition, treatment of 16HBE14o- monolayers with aldosterone (1 nM) inhibited by approximately 30 % the large and transient [Ca(2+)](i) increase induced by apical exposure to uridine triphosphate (UTP, 0.1 mM), a known secretagogue in airway epithelia. 3. Our results demonstrate for the first time that in human bronchial epithelial cells, aldosterone decreases [Ca(2+)](i) levels via a non-genomic mechanism. The hormone-induced changes to [Ca(2+)](i) involve stimulation of thapsigargin-sensitive Ca(2+)-ATPase, via G-protein-, adenylate cyclase- and protein kinase A-coupled signalling pathways.
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Affiliation(s)
- V Urbach
- INSERM U454, CHU Arnaud de Villeneuve, 34295 Montpellier, France.
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Estrada M, Liberona JL, Miranda M, Jaimovich E. Aldosterone- and testosterone-mediated intracellular calcium response in skeletal muscle cell cultures. Am J Physiol Endocrinol Metab 2000; 279:E132-9. [PMID: 10893332 DOI: 10.1152/ajpendo.2000.279.1.e132] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fast nongenomic steroid actions in several cell types seem to be mediated by second messengers such as intracellular calcium ([Ca(2+)](i)) and inositol 1,4,5-trisphosphate (IP(3)). We have shown the presence of both slow calcium transients and IP(3) receptors associated with cell nuclei in cultured skeletal muscle cells. The effect of steroids on [Ca(2+)](i) was monitored in Fluo 3-acetoxymethyl ester-loaded myotubes by either confocal microscopy or fluorescence microscopy, with the use of out-of-focus fluorescence elimination. The mass of IP(3) was determined by radioreceptor displacement assay. [Ca(2+)](i) changes after either aldosterone (10-100 nM) or testosterone (50-100 nM) were observed; a relatively fast (<2 min) calcium transient, frequently accompanied by oscillations, was evident with both hormones. A slow rise in [Ca(2+)](i) that reached its maximum after a 30-min exposure to aldosterone was also observed. Calcium responses seem to be fairly specific for aldosterone and testosterone, because several other steroid hormones do not induce detectable changes in fluorescence, even at 100-fold higher concentrations. The mass of IP(3) increased transiently to reach two- to threefold the basal level 45 s after addition of either aldosterone or testosterone, and the IP(3) transient was more rapid than the fast calcium signal. Spironolactone, an inhibitor of the intracellular aldosterone receptor, or cyproterone acetate, an inhibitor of the testosterone receptor, had no effect on the fast [Ca(2+)](i) signal or in the increase in IP(3) mass. These signals could mean that there are distinct nongenomic pathways for the action of these two steroids in skeletal muscle cells.
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Affiliation(s)
- M Estrada
- Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 6530499, Chile
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te Pas MF, de Jong PR, Verburg FJ. Glucocorticoid inhibition of C2C12 proliferation rate and differentiation capacity in relation to mRNA levels of the MRF gene family. Mol Biol Rep 2000; 27:87-98. [PMID: 11092555 DOI: 10.1023/a:1007120921064] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The muscle regulatory factors (MRF) gene family regulate muscle fibre development. Several hormones and drugs also affect muscle development. Glucocorticoids are the only drugs reported to have a beneficial effect on muscle degenerative disorders. We investigated the glucocorticoid-related effects on C2C12 myoblast proliferation rate, morphological differentiation, and subsequent mRNA expression patterns of the MRF genes. C2C12 cells were incubated with the glucocorticoids dexamethasone or alpha-methyl-prednisolone. Both glucocorticoids showed comparable effects. Glucocorticoid treatment of C2C12 cells during the proliferative phase reduced the proliferation rate of the cells dose dependently, especially during the third and fourth day of culture, increased MyoD1, myf-5, and MRF4 mRNA levels, and reduced myogenin mRNA level, compared to untreated control cells. Thus, the mRNA level of proliferation-specific MyoD1 and myf-5 expression does not seem to associate with C2C12 myoblast proliferation rate. Glucocorticoid treatment of C2C12 cells during differentiation reduced the differentiation capacity dose dependently, which is accompanied by a dose dependent reduction of myogenin mRNA level, and increased MyoD1, myf-5, and MRF4 mRNA levels compared to untreated control cells. Therefore, we conclude that glucocorticoid treatment reduces differentiation of C2C12 myoblasts probably through reduction of differentiation-specific myogenin mRNA level, while inducing higher mRNA levels of proliferation-associated MRF genes.
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Affiliation(s)
- M F te Pas
- Institute for Animial Science and Health, Department of Animal Breeding and Genetics, Lelystad, The Netherlands.
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45
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Ouyang M, Wang S. Dexamethasone attenuates the depressor response induced by neuropeptide Y microinjected into the nucleus tractus solitarius in rats. Br J Pharmacol 2000; 129:865-70. [PMID: 10696083 PMCID: PMC1571908 DOI: 10.1038/sj.bjp.0703122] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/1999] [Revised: 11/19/1999] [Accepted: 11/30/1999] [Indexed: 11/09/2022] Open
Abstract
An investigation was made of the effect of dexamethasone (Dex) injection into the nucleus tractus solitarius (NTS) on the cardiovascular response to neuropeptide Y in rats. Dex (39 pmol) injected into the NTS inhibited the hypotension and bradycardia caused by NPY (5 pmol) with a short latency (10 min) and a long duration of action (up to 4 h). The rapid inhibition by Dex (39 pmol) of the cardiovascular response to NPY was not blocked by pretreatment with the glucocorticoid receptor blocker, RU38486 (47 or 117 pmol respectively), but was reversed by bicuculline (30 pmol). Microiontophoresis of NPY (0.01 mM, pH 6.5) into the NTS increased the spontaneous firing of the majority (68.4%) of baroreflex-excited cells, but decreased the firing of most (73.7%) baroreflex-inhibited cells. In contrast, Dex (0.02 M, pH 6.5) decreased the spontaneous firing of the majority of baroreflex-excited cells (42.1% of normal response) and decreased the inhibition of baroreflex-inhibited cells (47.5% of normal response). The responses of the majority of baroreceptive cells to NPY were blocked by iontophoretic administration of Dex. Dex (200 microM) increased the delayed rectifier outward K+ current by 31.4+/-1.1% (n=5), whereas NPY alone, at a concentration of 1.5 microM, inhibited the current by 28.6+/-0.8% (n=5). In the presence of Dex (200 microM), addition of NPY (1.5 microM) had no effect on the current. In conclusion, NTS-administered-Dex attenuated the cardiovascular response to NPY injected into the same area via a rapid membrane effect, which was mediated by an action on GABA(A) receptors and on the delayed rectifier outward K(+) channel.
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Affiliation(s)
- Ming Ouyang
- Department of Physiology, Norman Bethune University of Medical Sciences, Changchun 130021, Jilin, China
| | - Shao Wang
- Department of Physiology, Norman Bethune University of Medical Sciences, Changchun 130021, Jilin, China
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46
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te Pas MF, de Jong PR, Verburg FJ, Duin M, Henning RH. Gender related and dexamethasone induced differences in the mRNA levels of the MRF genes in rat anterior tibial skeletal muscle. Mol Biol Rep 1999; 26:277-84. [PMID: 10634511 DOI: 10.1023/a:1007042414993] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Muscle formation and postnatal growth is under the control of the muscle regulatory factors (MRF) gene family, consisting of four genes: MyoD1, myogenin, myf-5, and myf-6. Muscle mass is also known to be affected by specific drugs, like glucocorticoids. Glucocorticoids have also been characterized as muscle atrophying agents. However, glucocorticoids are also the only drugs reported to have a beneficial effect on the treatment of muscle degenerative disorders. Since muscle mass relates to gender, this may be partially caused by gender. The aim of this study is to investigate gender-related basal and dexamethasone-induced expression of the MRF genes. Gender-specific MRF mRNA levels were investigated in anterior tibial muscles of the rat. Myogenin, myf-5, and myf-6 mRNA level was significantly higher in female rats than in male rats. Since muscle mass is usually higher in males, we conclude that the development of gender-related differences in muscle mass is not primarily under the control of the mRNA levels of the MRF genes. Male rats treated with dexamethasone for 14 days (1 mg per kg body weight) showed increased levels of MyoD1, myogenin and myf-5 compared to control male rats. Female rats treated with dexamethasone showed decreased expression of myf-6 compared to control female rats. These results suggest that dexamethasone increase satellite cell-specific MRF activity in male muscle tissue, which is suggested to be associated with muscle hypertrophy, while maintenance of muscle tissue is affected in female muscle tissue. Therefore, we conclude that both basal and dexamethasone-induced MRF gene mRNA levels are regulated gender-specific.
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Affiliation(s)
- M F te Pas
- Department of Animal Breeding and Genetics, DLO Institute for Animal Science and Health, Lelystad, The Netherlands.
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47
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Vandebrouck C, Imbert N, Duport G, Cognard C, Raymond G. The effect of methylprednisolone on intracellular calcium of normal and dystrophic human skeletal muscle cells. Neurosci Lett 1999; 269:110-4. [PMID: 10430517 DOI: 10.1016/s0304-3940(99)00418-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Clinical trials have shown that a glucocorticoid, the methyiprednisolone (PDN), has a beneficial effect on muscle strength and function in Duchenne muscular dystrophy (DMD) patients. The aim of this study was to test if the effect of PDN could be mediated via a possible action on intracellular calcium. The intracellular calcium activity, at rest and during calcium mobilizing drug superfusion protocols was recorded in normal and dystrophic human cocultured muscle cells. PDN (10 microM) pretreatment induced an elevation of the resting calcium concentration of 51, 34 and 38% in proliferating normal myoblasts, DMD myoblasts and DMD myotubes, respectively, while normal myotubes resting [Ca2+]i was not altered.
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Affiliation(s)
- C Vandebrouck
- Laboratoire de Biomembranes et Signalisation Cellulaire, CNRS UMR 6558, Université de Poitiers, Poitiers, France.
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