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Deja MA, Piekarska M, Malinowski M, Wiaderkiewicz R, Czekaj P, Machej L, Węglarzy A, Kowalówka A, Kołodziej T, Czech E, Plewka D, Mizia M, Latusek T, Szurlej B. Can human myocardium be remotely preconditioned? The results of a randomized controlled trial. Eur J Cardiothorac Surg 2019; 55:1086-1094. [PMID: 30649238 DOI: 10.1093/ejcts/ezy441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/02/2018] [Accepted: 11/17/2018] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES No experimental study has shown that the myocardium of a remotely preconditioned patient is more resistant to a standardized ischaemic/hypoxic insult. METHODS This was a single-centre randomized (1:1), double-blinded, sham-controlled, parallel-group study. Patients referred for elective coronary bypass surgery were allocated to either remote ischaemic preconditioning (3 cycles of 5-min ischaemia/5-min reperfusion of the right arm using a blood pressure cuff inflated to 200 mmHg) or sham intervention. One hundred and thirty-four patients were recruited, of whom 10 dropped out, and 4 were excluded from the per-protocol analysis. The right atrial trabecula harvested on cannulation for cardiopulmonary bypass was subjected to 60 min of simulated ischaemia and 120 min of reoxygenation in an isolated organ experiment. Postoperative troponin T release and haemodynamics were assessed in an in vivo study. RESULTS The atrial trabeculae obtained from remotely preconditioned patients recovered 41.9% (36.3-48.3) of the initial contraction force, whereas those from non-preconditioned patients recovered 45.9% (39.1-53.7) (P = 0.399). Overall, the content of cleaved poly (ADP ribose) polymerase in the right atrial muscle increased from 9.4% (6.0-13.5) to 19.1% (13.2-23.8) (P < 0.001) after 1 h of ischaemia and 2 h of reperfusion in vitro. The amount of activated Caspase 3 and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells also significantly increased. No difference was observed between the remotely preconditioned and sham-treated myocardium. In the in vivo trial, the area under the curve for postoperative concentration of troponin T over 72 h was 16.4 ng⋅h/ml (95% confidence interval 14.2-18.9) for the remote ischaemic preconditioning and 15.5 ng⋅h/ml (13.4-17.9) for the control group in the intention-to-treat analysis. This translated into an area under the curve ratio of 1.06 (0.86-1.30; P = 0.586). CONCLUSIONS Remote ischaemic preconditioning with 3 cycles of 5-min ischaemia/reperfusion of the upper limb before cardiac surgery does not make human myocardium more resistant to ischaemia/reperfusion injury. CLINICAL TRIAL REGISTRATION NUMBER NCT01994707.
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Affiliation(s)
- Marek A Deja
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland.,Department of Cardiac Surgery, Upper-Silesian Heart Center, Katowice, Poland
| | - Magda Piekarska
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland.,Department of Cardiac Surgery, Upper-Silesian Heart Center, Katowice, Poland
| | - Marcin Malinowski
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland.,Department of Cardiac Surgery, Upper-Silesian Heart Center, Katowice, Poland
| | - Ryszard Wiaderkiewicz
- Department of Histology and Embryology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Piotr Czekaj
- Department of Histology and Embryology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Leszek Machej
- Department of Anesthesia and Intensive Care Nursing, School of Health Sciences, Medical University of Silesia, Katowice, Poland
| | - Andrzej Węglarzy
- Department of Cardiac Anesthesia, Upper-Silesian Heart Center, Katowice, Poland
| | - Adam Kowalówka
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland.,Department of Cardiac Surgery, Upper-Silesian Heart Center, Katowice, Poland
| | - Tadeusz Kołodziej
- Department of Cardiac Surgery, Upper-Silesian Heart Center, Katowice, Poland
| | - Ewa Czech
- Department of Histology and Embryology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Danuta Plewka
- Department of Histology and Embryology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Magdalena Mizia
- 1 Department of Cardiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Tomasz Latusek
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Bartosz Szurlej
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
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Bøtker HE, Hausenloy D, Andreadou I, Antonucci S, Boengler K, Davidson SM, Deshwal S, Devaux Y, Di Lisa F, Di Sante M, Efentakis P, Femminò S, García-Dorado D, Giricz Z, Ibanez B, Iliodromitis E, Kaludercic N, Kleinbongard P, Neuhäuser M, Ovize M, Pagliaro P, Rahbek-Schmidt M, Ruiz-Meana M, Schlüter KD, Schulz R, Skyschally A, Wilder C, Yellon DM, Ferdinandy P, Heusch G. Practical guidelines for rigor and reproducibility in preclinical and clinical studies on cardioprotection. Basic Res Cardiol 2018; 113:39. [PMID: 30120595 PMCID: PMC6105267 DOI: 10.1007/s00395-018-0696-8] [Citation(s) in RCA: 304] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/18/2018] [Accepted: 08/03/2018] [Indexed: 02/07/2023]
Affiliation(s)
- Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, Palle-Juul Jensens Boulevard 99, 8200, Aarhus N, Denmark.
| | - Derek Hausenloy
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
- The National Institute of Health Research, University College London Hospitals Biomedial Research Centre, Research and Development, London, UK
- National Heart Research Institute Singapore, National Heart Centre, Singapore, Singapore
- Yon Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, 8 College Road, Singapore, 169857, Singapore
| | - Ioanna Andreadou
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece
| | - Salvatore Antonucci
- Department of Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35121, Padua, Italy
| | - Kerstin Boengler
- Institute for Physiology, Justus-Liebig University Giessen, Giessen, Germany
| | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Soni Deshwal
- Department of Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35121, Padua, Italy
| | - Yvan Devaux
- Cardiovascular Research Unit, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Fabio Di Lisa
- Department of Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35121, Padua, Italy
| | - Moises Di Sante
- Department of Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35121, Padua, Italy
| | - Panagiotis Efentakis
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece
| | - Saveria Femminò
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - David García-Dorado
- Experimental Cardiology, Vall d'Hebron Institut de Recerca (VHIR), Hospital Universitari Vall d'Hebron, Pg. Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Zoltán Giricz
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
- Pharmahungary Group, Szeged, Hungary
| | - Borja Ibanez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), IIS-Fundación Jiménez Díaz, CIBERCV, Madrid, Spain
| | - Efstathios Iliodromitis
- Second Department of Cardiology, Faculty of Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Nina Kaludercic
- Department of Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Via Ugo Bassi 58/B, 35121, Padua, Italy
| | - Petra Kleinbongard
- Institute for Pathophysiology, West German Heart and Vascular Center, University of Essen Medical School, Essen, Germany
| | - Markus Neuhäuser
- Department of Mathematics and Technology, Koblenz University of Applied Science, Remagen, Germany
- Institute for Medical Informatics, Biometry, and Epidemiology, University Hospital Essen, Essen, Germany
| | - Michel Ovize
- Explorations Fonctionnelles Cardiovasculaires, Hôpital Louis Pradel, Lyon, France
- UMR, 1060 (CarMeN), Université Claude Bernard, Lyon1, Villeurbanne, France
| | - Pasquale Pagliaro
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Michael Rahbek-Schmidt
- Department of Cardiology, Aarhus University Hospital, Palle-Juul Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Marisol Ruiz-Meana
- Experimental Cardiology, Vall d'Hebron Institut de Recerca (VHIR), Hospital Universitari Vall d'Hebron, Pg. Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | | | - Rainer Schulz
- Institute for Physiology, Justus-Liebig University Giessen, Giessen, Germany
| | - Andreas Skyschally
- Institute for Pathophysiology, West German Heart and Vascular Center, University of Essen Medical School, Essen, Germany
| | - Catherine Wilder
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Peter Ferdinandy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
- Pharmahungary Group, Szeged, Hungary
| | - Gerd Heusch
- Institute for Pathophysiology, West German Heart and Vascular Center, University of Essen Medical School, Essen, Germany.
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Kleinbongard P, Gedik N, Kirca M, Stoian L, Frey U, Zandi A, Thielmann M, Jakob H, Peters J, Kamler M, Heusch G. Mitochondrial and Contractile Function of Human Right Atrial Tissue in Response to Remote Ischemic Conditioning. J Am Heart Assoc 2018; 7:e009540. [PMID: 30371229 PMCID: PMC6201459 DOI: 10.1161/jaha.118.009540] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/27/2018] [Indexed: 01/02/2023]
Abstract
Background Remote ischemic preconditioning ( RIPC ) by repeated brief cycles of limb ischemia/reperfusion attenuates myocardial ischemia/reperfusion injury. We aimed to identify a functional parameter reflecting the RIPC -induced protection in human. Therefore, we measured mitochondrial function in right atrial tissue and contractile function of isolated right atrial trabeculae before and during hypoxia/reoxygenation from patients undergoing coronary artery bypass grafting with RIPC or placebo, respectively. Methods and Results One hundred thirty-seven patients under isoflurane anesthesia underwent RIPC (3×5 minutes blood pressure cuff inflation on the left upper arm/5 minutes deflation, n=67) or placebo (cuff uninflated, n=70), and right atrial appendages were harvested before ischemic cardioplegic arrest. Myocardial protection by RIPC was assessed from serum troponin I/T concentrations over 72 hours after surgery. Atrial tissue was obtained for isolation of mitochondria ( RIPC /placebo: n=10/10). Trabeculae were dissected for contractile function measurements at baseline and after hypoxia/reoxygenation (60 min/30 min) and for western blot analysis after hypoxia/reoxygenation ( RIPC /placebo, n=57/60). Associated with cardioprotection by RIPC (26% decrease in the area under the curve of troponin I/T), mitochondrial adenosine diphosphate-stimulated complex I respiration (+10%), adenosine triphosphate production (+46%), and calcium retention capacity (+37%) were greater, whereas reactive oxygen species production (-24%) was less with RIPC than placebo. Contractile function was improved by RIPC (baseline, +7%; reoxygenation, +24%). Expression and phosphorylation of proteins, which have previously been associated with cardioprotection, were not different between RIPC and placebo. Conclusions Cardioprotection by RIPC goes along with improved mitochondrial and contractile function of human right atrial tissue. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT 01406678.
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Affiliation(s)
- Petra Kleinbongard
- Institut für PathophysiologieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Nilguen Gedik
- Institut für PathophysiologieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Mücella Kirca
- Institut für PathophysiologieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Leanda Stoian
- Institut für PathophysiologieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Ulrich Frey
- Klinik für Anästhesiologie und IntensivmedizinUniversitätsklinikum EssenGermany
| | - Afsaneh Zandi
- Herzchirurgie Essen‐HuttropWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Matthias Thielmann
- Klinik für Thorax‐ und Kardiovaskuläre ChirurgieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Heinz Jakob
- Klinik für Thorax‐ und Kardiovaskuläre ChirurgieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Jürgen Peters
- Klinik für Anästhesiologie und IntensivmedizinUniversitätsklinikum EssenGermany
| | - Markus Kamler
- Herzchirurgie Essen‐HuttropWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
| | - Gerd Heusch
- Institut für PathophysiologieWestdeutsches Herz‐ und GefäßzentrumUniversitätsklinikum EssenGermany
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Janjua MB, Makepeace CM, Anastacio MM, Schuessler RB, Nichols CG, Lawton JS. Cardioprotective benefits of adenosine triphosphate-sensitive potassium channel opener diazoxide are lost with administration after the onset of stress in mouse and human myocytes. J Am Coll Surg 2014; 219:803-13. [PMID: 25158912 DOI: 10.1016/j.jamcollsurg.2014.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/28/2014] [Accepted: 05/06/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Adenosine triphosphate-sensitive (KATP) potassium channel opener diazoxide (DZX) maintains myocyte volume and contractility during stress via an unknown mechanism when administered at the onset of stress. This study was performed to investigate the cardioprotective potential of DZX when added after the onset of the stresses of hyperkalemic cardioplegia, metabolic inhibition, and hypo-osmotic stress. STUDY DESIGN Isolated mouse ventricular and human atrial myocytes were exposed to control Tyrode's solution (TYR) for 10 to 20 minutes, test solution for 30 minutes (hypothermic hyperkalemic cardioplegia [CPG], CPG + 100uM diazoxide [CPG+DZX], metabolic inhibition [MI], MI+DZX, mild hypo-osmotic stress [0.9T], or 0.9T + DZX), with DZX added after 10 or 20 minutes of stress, followed by 20 minutes of re-exposure to TYR (±DZX). Myocyte volume (human + mouse) and contractility (mouse) were compared. RESULTS Mouse and human myocytes demonstrated significant swelling during exposure to CPG, MI, and hypo-osmotic stress that was not prevented by DZX when administered either at 10 or 20 minutes after the onset of stress. Contractility after the stress of CPG in mouse myocytes significantly declined when DZX was administered 20 minutes after the onset of stress (p < 0.05 vs TYR). Contractility after hypo-osmotic stress in mouse myocytes was not altered by the addition of DZX. CONCLUSIONS To maintain myocyte volume homeostasis and contractility during stress (hyperkalemic cardioplegia, metabolic inhibition, and hypo-osmotic stress), KATP channel opener diazoxide requires administration at the onset of stress in this isolated myocyte model. These data have potential implications for any future clinical application of diazoxide.
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Affiliation(s)
- M Burhan Janjua
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Carol M Makepeace
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Melissa M Anastacio
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Richard B Schuessler
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO
| | - Jennifer S Lawton
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO.
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Costa JF, Fontes-Carvalho R, Leite-Moreira AF. Myocardial remote ischemic preconditioning: From pathophysiology to clinical application. REVISTA PORTUGUESA DE CARDIOLOGIA (ENGLISH EDITION) 2013. [DOI: 10.1016/j.repce.2013.10.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Costa JF, Fontes-Carvalho R, Leite-Moreira AF. Pré-condicionamento isquémico remoto do miocárdio: dos mecanismos fisiopatológicos à aplicação na prática clínica. Rev Port Cardiol 2013; 32:893-904. [DOI: 10.1016/j.repc.2013.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 12/14/2022] Open
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Deja MA, Malinowski M, Gołba KS, Kajor M, Lebda-Wyborny T, Hudziak D, Domaradzki W, Szurlej D, Bończyk A, Biernat J, Woś S. Diazoxide protects myocardial mitochondria, metabolism, and function during cardiac surgery: a double-blind randomized feasibility study of diazoxide-supplemented cardioplegia. J Thorac Cardiovasc Surg 2009; 137:997-1004, 1004e1-2. [PMID: 19327530 DOI: 10.1016/j.jtcvs.2008.08.068] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 08/06/2008] [Accepted: 08/27/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The study was designed to assess whether diazoxide-mediated cardioprotection might be used in human subjects during cardiac surgery. METHODS Forty patients undergoing coronary artery bypass grafting were randomized to receive intermittent warm blood antegrade cardioplegia supplemented with either diazoxide (100 micromol/L) or placebo (n = 20 in each group). Mitochondria were assessed before and after ischemia and reperfusion in myocardial biopsy specimens. Myocardial oxygen and glucose and lactic acid extraction ratios were measured before ischemia and in the first 20 minutes of reperfusion. Hemodynamic data were collected, and troponin I, creatine kinase-MB, and N-terminal prohormone brain natriuretic peptide levels were measured. All outcomes were analyzed by using mixed-effects modeling for repeated measures. RESULTS No deaths, strokes, or infarcts were observed. Patients received, on average, 36.2 +/- 1.2 mg of diazoxide and 37.3 +/- 1.9 mg of placebo (P = .6). Diazoxide added to cardioplegia prevented mitochondrial swelling (8899 +/- 474 vs 9273 +/- 688 pixels before and after the procedure, respectively; P = .6) compared with that seen in the placebo group (8474 +/- 163 vs 11,357 +/- 759 pixels, P = .004). No oxygen debt was observed in the diazoxide group. Glucose consumption and lactic acid production returned to preischemic values faster in the diazoxide group. The following hemodynamic parameters differed between the diazoxide and placebo groups, respectively, in the postoperative period: cardiac index, 3.0 +/- 0.09 versus 2.6 +/- 0.09 L . min(-1) . m(-2) (P = .002); left cardiac work index, 2.81 +/- 0.07 versus 2.31 +/- 0.07 kg/m(2) (P < .001); oxygen delivery index, 420 +/- 14 versus 377 +/- 13 mL . min(-1) . m(-2) (P = .03); and oxygen extraction ratio, 29.3% +/- 1.1% versus 32.6% +/- 1.1% (P = .02). Postoperative myocardial enzyme levels did not differ, but N-terminal prohormone brain natriuretic peptide levels were lower in the diazoxide group (120 +/- 27 vs 192 +/- 29 pg/mL, P = .04). CONCLUSIONS Supplementing blood cardioplegia with diazoxide is safe and improves myocardial protection during cardiac surgery, possibly through its influence on the mitochondria.
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Affiliation(s)
- Marek A Deja
- Second Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland.
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8
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Al-Dadah AS, Voeller RK, Schuessler RB, Damiano RJ, Lawton JS. Maintenance of myocyte volume homeostasis during stress by diazoxide is cardioprotective. Ann Thorac Surg 2007; 84:857-62. [PMID: 17720390 DOI: 10.1016/j.athoracsur.2007.04.103] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 04/20/2007] [Accepted: 04/24/2007] [Indexed: 11/16/2022]
Abstract
BACKGROUND We previously demonstrated that myocyte swelling and reduced contractility secondary to hyperkalemic cardioplegia and hyposmotic stress are attenuated by the addition of diazoxide, an adenosine triphosphate-sensitive potassium channel (K(ATP)) opener. The goal of this study was to investigate the effect of diazoxide on myocyte swelling and reduced contractility after metabolic inhibition and to attempt to summarize the potential mechanisms involved. METHODS Isolated rabbit myocytes were perfused with Tyrode's control solution for 20 minutes, followed by test solution for 20 minutes. Test solutions included (1) Tyrode's control, (2) a metabolic inhibition solution containing sodium cyanide and 2-deoxyglucose, (3) metabolic inhibition plus diazoxide, (4) metabolic inhibition plus diazoxide plus HMR1098 (a sarcolemmal K(ATP)-channel blocker), or (5) metabolic inhibition plus diazoxide plus 5-hydroxydeconoate (a mitochondrial K(ATP)-channel blocker). Myocytes were then reexposed to Tyrode's solution for 20 minutes. Volume measurements were taken every 5 minutes. Contractility was recorded using edge-detection software at baseline and at 10 and 20 minutes of reexposure to Tyrode's solution. RESULTS Simulated ischemia (metabolic inhibition) caused significant myocyte swelling and associated reduced contractility. The addition of diazoxide abolished myocyte swelling and attenuated the associated reduced contractility. Observations with diazoxide were unchanged by the addition of HMR 1098 or 5-hydroxydeconoate. CONCLUSIONS Diazoxide, with or without either K(ATP)-channel blocker, attenuated the significant myocyte swelling and reduced contractility secondary to metabolic inhibition. These data suggest a role for diazoxide, independent of the K(ATP) channel, in myocyte volume homeostasis. In addition, the prevention of myocyte swelling resulted in improved contractility, consistent with previous data and the hypothesis that myocyte swelling may participate in the phenomenon of myocardial stunning.
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Affiliation(s)
- Ashraf S Al-Dadah
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Chambers DJ. Invited commentary. Ann Thorac Surg 2006; 81:1416. [PMID: 16564283 DOI: 10.1016/j.athoracsur.2006.01.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 01/09/2006] [Accepted: 01/13/2006] [Indexed: 10/24/2022]
Affiliation(s)
- David J Chambers
- The Rayne Institute, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Campus, London, SE1 7EH, United Kingdom.
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