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Huang J, Ruse RB, Walcott GP, Litovsky S, Bohanan SJ, Gong DW, Kroll MW. Ascending Defibrillation Waveform Significantly Reduces Myocardial Morphological Damage and Injury Current. JACC Clin Electrophysiol 2019; 5:854-862. [PMID: 31320015 DOI: 10.1016/j.jacep.2019.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/19/2019] [Accepted: 04/17/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVES This study tested the hypothesis that a biphasic defibrillation waveform with an ascending first phase (ASC) causes less myocardial damage by pathology and injury current than a standard biphasic truncated exponential (BTE) waveform in a swine model. BACKGROUND Although lifesaving, defibrillation shocks have significant iatrogenic effects that reduce their benefit for patient survival. METHODS An ASC waveform with an 8-ms linear ramp followed by an additional positive 0.5-ms decaying portion with amplitudes of 20 J (ASC 20J) and 25 J (ASC 25J) was used. The control was a 25-J BTE conventional waveform (BTE 25J) RESULTS: The ASC 20J and ASC 25J shocks were both successful in 6 of 6 pigs, but the BTE 25J was successful in only 6 of 14 pigs (p < 0.05). Post-shock ST-segment elevation (injury current) in the right ventricular electrode was significantly greater with BTE 25J than with ASC 20J and ASC 25J. With a blinded pathology reading, hemorrhage, inflammation, thrombi, and necrosis 24 h post-shock were significantly greater with BTE 25J than with ASC 20J and ASC 25J. Troponin levels were also markedly lower at 3, 4, 5, and 6 h post-shock. CONCLUSIONS Defibrillation shocks cause electrophysiological, histological, and biochemical signs of myocardial damage and necrosis. These signs of damage are markedly less for an ASC waveform than for a conventional BTE waveform.
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Affiliation(s)
- Jian Huang
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Gregory P Walcott
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama
| | - Silvio Litovsky
- Department of Medicine, Department of Pathology, University of Alabama at Birmingham, Alabama
| | | | - Da-Wei Gong
- School of Medicine, University of Maryland, Baltimore, Maryland
| | - Mark W Kroll
- Department of Biomedical Engineering, University of Minnesota Crystal Bay, Minnesota; Department of Biomedical Engineering, California Polytechnical University, San Luis Obispo, California.
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Vagus Nerve Attenuates Hepatocyte Apoptosis upon Ischemia-Reperfusion via α7 Nicotinic Acetylcholine Receptor on Kupffer Cells in Mice. Anesthesiology 2017; 125:1005-1016. [PMID: 27560466 DOI: 10.1097/aln.0000000000001309] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hepatic ischemia-reperfusion (HIR) injury is a complication of liver surgery. As much as 50% of hepatocytes undergo apoptosis within the first 24 h of reperfusion. The neurotransmitters of the vagus nerve can activate α7 nicotinic acetylcholine receptor (α7nAChR) on macrophages. The function of Kupffer cells (KCs) determines HIR injury. We hypothesize that the vagus nerve could attenuate HIR-induced hepatocyte apoptosis by activating α7nAChR on KCs. METHODS Hepatic vagotomized C57BL/6J mice, KC-eliminated C57BL/6J mice, and α7nAChR mice were used for HIR. Primary KCs and hepatocytes were subjected to hypoxia/reoxygenation (HR). Liver injury, hepatocyte apoptosis, reactive oxygen species (ROS) production, and soluble CD163 were measured. RESULTS Hepatic vagotomy and α7nAChR caused higher levels of alanine transaminase and liver caspase-3 and -8 activity by HIR. Activating α7nAChR attenuated these changes in wild-type but not in the α7nAChR mice. Furthermore, activating α7nAChR diminished hepatic injury and reduced liver apoptosis by HIR in vagotomized mice. In vitro, activating α7nAChR reduced apoptosis of hepatocytes cocultured with KCs that suffered HR. Similar to the effects by catalase, activating α7nAChR on KCs reduced ROS and H2O2 by HR. The supernatant from KCs, with α7nAChR activated or catalase treated, prevented hepatocyte apoptosis by HR. Finally, KC elimination reduced HIR-induced H2O2 production in mice. Activating α7nAChR significantly attenuated soluble CD163 both in mice by HIR (serum: 240 ± 34 vs. 446 ± 72; mean ± SD; n = 8; P < 0.01) and in KCs by HR (supernatant: 4.23 ± 0.06 vs. 5.60 ± 0.18; n = 3; P < 0.01). CONCLUSIONS The vagus nerve could minimize HIR-induced liver apoptosis through activating α7nAChR on KCs possibly by preventing their excessive ROS production.
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Tsai MS, Huang CH, Tsai CY, Chen HW, Cheng HJ, Hsu CY, Chang WT, Chen WJ. Combination of intravenous ascorbic acid administration and hypothermia after resuscitation improves myocardial function and survival in a ventricular fibrillation cardiac arrest model in the rat. Acad Emerg Med 2014; 21:257-65. [PMID: 24628750 DOI: 10.1111/acem.12335] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 01/23/2023]
Abstract
OBJECTIVES Intravenous (IV) administration of ascorbic acid during cardiopulmonary resuscitation (CPR) was reported to facilitate defibrillation and improves survival in ventricular fibrillation (VF) cardiac arrest. We investigated whether IV administration of ascorbic acid after return of spontaneous circulation (ROSC) can improve outcomes in VF cardiac arrest in a rat model and its interaction with therapeutic hypothermia. METHODS Ventricular fibrillation-induced cardiac arrest followed by CPR and defibrillation was performed in male Wistar rats. After ROSC, the animals were equally randomized to the normothermia (NormoT), hypothermia (HypoT), ascorbic acid (AA+NormoT), and ascorbic acid plus hypothermia (AA+HypoT) groups. The AA+NormoT and AA+HypoT groups received IV ascorbic acid (100 mg/kg). In the HypoT and AA+HypoT groups, therapeutic hypothermia was maintained at 32°C for 2 hours. RESULTS There were 12 rats in each group. Within 4 hours after ROSC, the HypoT, AA+NormoT, and AA+HypoT groups had significantly lower myocardial lipid peroxidation than the NormoT group. Within 4 hours following ROSC, the AA+NormoT group had a significantly better systolic function (dp/dt40 ) than the NormoT group (6887.9 mm Hg/sec, SD ± 1049.7 mm Hg/sec vs. 5953.6 mm Hg/sec, SD ± 1161.9 mm Hg/sec; p < 0.05). The AA+HypoT group also showed a significantly better diastolic function (-dp/dtmax ) than the HypoT group (dp/dt40 : 8524.8, SD ± 1166.7 mm Hg/sec vs. 7399.8 mm Hg/sec, SD ± 1114.5 mmHg/sec; dp/dtmax : -8183.4 mm Hg/sec, SD ± 1359.0 mm Hg/sec vs. -6573.7 mm Hg/sec, SD ± 1110.9 mm Hg/sec; p < 0.05) at the fourth hour following ROSC. Also at 4 hours, there was less myocytolysis in the HypoT, AA+NormoT, and AA+HypoT groups than the NormoT group. The HypoT, AA+NormoT, and AA+HypoT groups had significantly better survival rates and neurologic outcomes than the NormoT group. Compared with only five surviving animals in the NormoT group, there were nine, eight, and 10 in the HypoT, AA+NormoT, and AA+HypoT groups, respectively, with good neurologic outcomes at 72 hours. CONCLUSIONS Intravenous ascorbic acid administration after ROSC in normothermia may mitigate myocardial damage and improve systolic function, survival rate, and neurologic outcomes in VF cardiac arrest of rat. Combination of ascorbic acid and hypothermia showed an additive effect in improving both systolic and diastolic functions after ROSC.
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Affiliation(s)
- Min-Shan Tsai
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
| | - Chien-Hua Huang
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
| | - Chia-Ying Tsai
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
| | - Huei-Wen Chen
- The Graduate Institute of Toxicology; College of Medicine; National Taiwan University; Taipei Taiwan
| | - Hsaio-Ju Cheng
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
| | - Chiung-Yuan Hsu
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
| | - Wei-Tien Chang
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
| | - Wen-Jone Chen
- The Department of Emergency Medicine; National Taiwan University Medical College and Hospital; Taipei Taiwan
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Effects of bone marrow mesenchymal stem cells in a rat model of myocardial infarction. Resuscitation 2012; 83:1391-6. [DOI: 10.1016/j.resuscitation.2012.02.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 02/15/2012] [Accepted: 02/21/2012] [Indexed: 01/14/2023]
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Zhang Y, Lv SJ, Yan H, Wang L, Liang GP, Wan QX, Peng X. Effects of glycine supplementation on myocardial damage and cardiac function after severe burn. Burns 2012; 39:729-35. [PMID: 23036846 DOI: 10.1016/j.burns.2012.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 08/06/2012] [Accepted: 09/05/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Glycine has been shown to participate in protection from hypoxia/reoxygenation injury. However, the cardioprotective effect of glycine after burn remains unclear. This study aimed to explore the protective effect of glycine on myocardial damage in severely burned rats. METHODS Seventy-two Wistar rats were randomly divided into three groups: normal controls (C), burned controls (B), and glycine-treated (G). Groups B and G were given a 30% total body surface area full-thickness burn. Group G was administered 1.5 g/(kg d) glycine and group B was given the same dose of alanine via intragastric administration for 3d. Serum creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST), and blood lactate, as well as myocardial ATP and glutathione (GSH) content, were measured. Cardiac contractile function and histopathological changes were analyzed at 12, 24, 48, and 72 hours. RESULTS Serum CK, LDH, AST, and blood lactate increased, while myocardial ATP and GSH content decreased in both burned groups. Compared with group B, the levels of CK, LDH, and AST significantly decreased, whereas blood lactate as well as myocardial ATP and GSH content increased in group G. Moreover, cardiac contractile function inhibition and myocardial histopathological damage in group G significantly decreased compared with group B. CONCLUSION Myocardial histological structure and function were damaged significantly after burn. Glycine is beneficial to myocardial preservation by improving cardiomyocyte energy metabolism and increasing ATP and GSH abundance.
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Affiliation(s)
- Yong Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burns of PLA, Southwest Hospital, Third Military Medical University, Chongqing 400038, PR China
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Tsai MS, Huang CH, Tsai CY, Hsu CY, Chang WT, Chen WJ. Intravenous ascorbic acid administration following ROSC, with and without hypothermia, both improved myocardial dysfunction and survival in cardiac arrest of ventricular fibrillation. Resuscitation 2012. [DOI: 10.1016/j.resuscitation.2012.08.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Post-cardiac arrest myocardial dysfunction is improved with cyclosporine treatment at onset of resuscitation but not in the reperfusion phase. Resuscitation 2012; 82 Suppl 2:S41-7. [PMID: 22208177 DOI: 10.1016/s0300-9572(11)70150-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AIM OF STUDY Significant myocardial dysfunction and high mortality occur after whole-body ischaemia-eperfusion injuries in the post-cardiac arrest status. The inhibition of mitochondrial permeability transition pore (mPTP) opening during ischaemia-reperfusion can ameliorate injuries in the specific organs. We investigated the effect and therapeutic window of pharmacological inhibition of mPTP opening in cardiac arrest. METHODS Forty male Wistar rats were resuscitated after cardiac arrest induced by 8.5 min of asphyxia. Cyclosporine (10 mg/kg) was administered intravenously at onset of resuscitation in protocol 1 study and administered 3 min after ROSC in protocol 2 with placebo control in both. RESULTS Left ventricular systolic (dP/dt 40), diastolic (maximal negative dP/dt) functions and cardiac output were improved in the group with cyclosporine treatment at onset of resuscitation compared to control group (p < 0.01, respectively). Seventy-two hour survival was better in the group with cyclosporine treatment at onset of resuscitation compared to control (p = 0.046). Left ventricular systolic and diastolic function, cardiac output and 72 h survival were not improved in the group with cyclosporine treatment 3 min after ROSC. The severity of mitochondrial damage under electronic microscopy, mPTP opening, mitochondrial respiratory control ratio and ADP:O ratio were ameliorated in the group with cyclosporine treatment at onset of resuscitation (p< 0.05, respectively) but not in the group with cyclosporine treatment at 3 min after ROSC. CONCLUSIONS Post-cardiac arrest myocardial dysfunction and survival can be improved by cyclosporine treatment at onset of resuscitation, but not by the cyclosporine treatment at 3 min after ROSC.
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Antonelli M, Bonten M, Chastre J, Citerio G, Conti G, Curtis JR, De Backer D, Hedenstierna G, Joannidis M, Macrae D, Mancebo J, Maggiore SM, Mebazaa A, Preiser JC, Rocco P, Timsit JF, Wernerman J, Zhang H. Year in review in Intensive Care Medicine 2011: I. Nephrology, epidemiology, nutrition and therapeutics, neurology, ethical and legal issues, experimentals. Intensive Care Med 2012; 38:192-209. [PMID: 22215044 PMCID: PMC3291847 DOI: 10.1007/s00134-011-2447-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 12/14/2011] [Indexed: 12/29/2022]
Affiliation(s)
- Massimo Antonelli
- Department of Intensive Care and Anesthesiology, Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Rome, Italy.
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Tsai MS, Huang CH, Tsai CY, Chen HW, Lee HC, Cheng HJ, Hsu CY, Wang TD, Chang WT, Chen WJ. Ascorbic acid mitigates the myocardial injury after cardiac arrest and electrical shock. Intensive Care Med 2011; 37:2033-40. [PMID: 21953354 DOI: 10.1007/s00134-011-2362-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 07/31/2011] [Indexed: 10/17/2022]
Abstract
PURPOSE To examine the effects of ascorbic acid (AA) administrated during cardiopulmonary resuscitation (CPR) on the myocardial injury in a rat model of ventricular fibrillation (VF) and electrical shock (ES). METHODS VF was induced in male Wistar rats and left untreated for 5 min, followed by 1 min of CPR, and then one ES of 5 J. At the start of CPR, animals received either intravenous administration of AA (100 mg/kg) or Tempol (30 mg/kg), two antioxidants, or 0.9% saline (VF + ES group). After ES, animals were immediately killed. Myocardial lipoxidation was determined by malondialdehyde (MDA) assay. The histology and ultrastructural changes of myocardium were also evaluated. The mitochondrial permeability transition pore (mPTP) opening was measured based on the mitochondrial swelling rate. The complex activities and respiration of mitochondria were assessed, too. RESULTS Increased myocardial injury and mitochondrial damage in the VF + ES group were noted. AA and Tempol alleviated such damages. Both AA and Tempol improved accelerated mitochondrial swelling; decreased complex activities and respiratory dysfunction occurred in the VF + ES group. The animals receiving AA and Tempol during CPR had better successful resuscitation rates and 72-h survival than the VF + ES group. CONCLUSIONS Intravenous administration of AA and Tempol at the start of CPR may reduce lipid peroxidation and myocardial necrosis, diminish mitochondrial damage, facilitate resuscitation, and improve outcomes after VF + ES.
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Affiliation(s)
- Min-Shan Tsai
- Department of Emergency Medicine, National Taiwan University Hospital, No. 7, Chung-Shan S. Road, Taipei, 100, Taiwan
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Ristagno G, Tantillo S, Sun S, Weil MH, Tang W. Hypothermia improves ventricular myocyte contractility under conditions of normal perfusion and after an interval of ischemia. Resuscitation 2010; 81:898-903. [PMID: 20395031 DOI: 10.1016/j.resuscitation.2010.03.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 02/17/2010] [Accepted: 03/19/2010] [Indexed: 11/18/2022]
Abstract
AIM Recent investigations have reported improved myocardial function during hypothermia following resuscitation from cardiac arrest. The effects of hypothermia on myocyte contractility were investigated under conditions of normal perfusion and after a 10min interval of ischemia. METHODS Ventricular myocytes were obtained from 10 male Sprague-Dawley rats weighing 400+/-50g. The myocytes were randomized to be perfused at: 37 degrees C, 34 degrees C, 32 degrees C, or 30 degrees C. A subsequent set of myocytes was subjected to 10min of ischemia at 37 degrees C, prior to being randomized to reperfusion at: 37 degrees C, 34 degrees C, 32 degrees C or 30 degrees C. Myocyte contractility was expressed as length-shortening percentage. Intracellular Ca(2+) transients were assessed in a separate group of myocytes preloaded with Fura-2/AM. Sensitivity to Ca(2+) was tested by increasing perfusate Ca(2+) content, i.e. 0.5mM, 1mM and 2mM. RESULTS During normal perfusion and following reperfusion after 10min of ischemia, myocyte contractility increased at 34 degrees C compared to 37 degrees C (P<0.01). When the perfusion temperature was decreased to 32 degrees C and 30 degrees C, contractility further increased (P<0.001). Intracellular Ca(2+) transients were greater during perfusion at 34 degrees C compared to those at 37 degrees C (P<0.001) and further increased at 30 degrees C (P<0.001). Increases in extracellular Ca(2+) concentration from 0.5mM to 2mM resulted in greater myocyte contractility during perfusion at 30 degrees C compared to that observed at 37 degrees C (P<0.001). Effects of hypothermia on intracellular Ca(2+) transients and sensitivity to Ca(2+) persisted after ischemia. CONCLUSIONS Hypothermia improved myocyte contractility, intracellular Ca(2+) transients and sensitivity to Ca(2+) under conditions of normal perfusion and following reperfusion after 10min of ischemia.
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Affiliation(s)
- Giuseppe Ristagno
- Weil Institute of Critical Care Medicine, Rancho Mirage, CA 92270, USA
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Huang CH, Chen HW, Tsai MS, Hsu CY, Peng RH, Wang TD, Chang WT, Chen WJ. Antiapoptotic cardioprotective effect of hypothermia treatment against oxidative stress injuries. Acad Emerg Med 2009; 16:872-80. [PMID: 19673708 DOI: 10.1111/j.1553-2712.2009.00495.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The effect of hypothermia on cardiomyocyte injury induced by oxidative stress remains unclear. The authors investigated the effects of hypothermia on apoptosis and mitochondrial dysfunction in cardiomyocytes exposed to oxidative stress. METHODS Cardiomyocytes (H9c2) derived from embryonic rat heart cell culture were exposed to either normothermic (37 degrees C) or hypothermic (31 degrees C) environments before undergoing oxidative stress via treatment with hydrogen peroxide (H(2)O(2)). The degree of apoptosis was determined by annexin V and terminal deoxynucleotidyl transferase (TUNEL) staining. The amount of reactive oxygen species (ROS) was compared after H(2)O(2) exposure between normo- and hypothermic-pretreated groups. Mitochondrial dysfunction in both groups was measured by differential reductase activity and transmembrane potential (DeltaPsim). RESULTS Hydrogen peroxide induced significant apoptosis in both normothermic and hypothermic cardiomyocytes. Hypothermia ameliorated apoptosis as demonstrated by decreased annexin V staining (33 +/- 1% vs. 49 +/- 4%; p < 0.05) and TUNEL staining (27 +/- 17% vs. 80 +/-25%; p < 0.01). The amount of intracellular ROS increased after H(2)O(2) treatment and was higher in the hypothermic group than that in the normothermic group (237.9 +/- 31.0% vs. 146.6 +/- 20.6%; p < 0.05). In the hypothermic group, compared with the normothermic group, after H(2)O(2) treatment mitochondrial reductase activity was greater (72.0 +/- 17.9% vs. 27.0 +/- 13.3%; p < 0.01) and the mitochondria DeltaPsim was higher (101.0 +/- 22.6% vs. 69.7 +/- 12.9%; p < 0.05). Pretreatment of cardiomyocytes with the antioxidant ascorbic acid diminished the hypothermia-induced increase in intracellular ROS and prevented the beneficial effects of hypothermia on apoptosis and mitochondrial function. CONCLUSIONS Hypothermia at 31 degrees C can protect cardiomyocytes against oxidative stress-induced injury by decreasing apoptosis and mitochondrial dysfunction through intracellular ROS-dependent pathways.
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Affiliation(s)
- Chien-Hua Huang
- Department of Emergency Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County
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Individual effect of components of defibrillation waveform on the contractile function and intracellular calcium dynamics of cardiomyocytes. Crit Care Med 2009; 37:2394-401. [PMID: 19531953 DOI: 10.1097/ccm.0b013e3181a02ea1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Although electrical shock is a unique and effective treatment for fatal arrhythmia, it produces myocardial dysfunction closely related to the intensity of shock delivered. The isolated contribution of defibrillator components to postshock contractile impairment is not yet securely established. We sought to evaluate contractile function in cardiomyocytes following electrical shocks with different peak currents, energies, and durations. We hypothesized that peak current may play a more important role than energy in determining postshock dysfunction. Prolongation of the duration may reduce contractile impairment. DESIGN Prospective, randomized, controlled study. SETTING University-affiliated research institute. SUBJECTS Male albino Sprague-Dawley rats. INTERVENTIONS We assigned 324 cardiomyocytes isolated from adult male rats to 11 groups having different waveforms (triangular and square), peak currents (derived from peak voltage gradients of 25 V/cm, 35.4 V/cm, 50 V/cm, 70.7 V/cm, and 100 V/cm), and durations (10 and 20 msecs) of shocks delivered. One single shock was given to each cardiomyocyte, and length shortening and Ca transients were recorded optically with fura-2 loading. MEASUREMENTS AND MAIN RESULTS Increase of peak current and corresponding energy caused more cells to have irregular beating (p < .001) and reduced length shortening (p < .001). This was associated with increased Ca abnormality (p < .05). Increasing peak current independent of energy significantly impaired postshock contractile function (p < .05), whereas the change of energy alone did not. Prolongation of duration independent of energy and peak current reduced postshock contractile impairment (p < .05). CONCLUSIONS Peak current may play a more determinative role in producing postshock contractile dysfunction than does energy.
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Free radicals mediate postshock contractile impairment in cardiomyocytes--translating experimental studies into clinical practice. Crit Care Med 2009; 37:1831; author reply 1831. [PMID: 19373072 DOI: 10.1097/ccm.0b013e3181a0965d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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The role of reactive oxygen species in the heart after electrical stimulation. Crit Care Med 2008; 36:3274-5. [PMID: 19020442 DOI: 10.1097/ccm.0b013e31818bda8d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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