Isoflurane Preconditions Myocardium against Infarction via  Release of Free Radicals

2002 ◽  
Vol 96 (4) ◽  
pp. 934-940 ◽  
Author(s):  
Jost Müllenheim ◽  
Dirk Ebel ◽  
Jan Fräβdorf ◽  
Benedikt Preckel ◽  
Volker Thämer ◽  
...  

Background Isoflurane exerts cardioprotective effects that mimic the ischemic preconditioning phenomenon. Generation of free radicals is implicated in ischemic preconditioning. The authors investigated whether isoflurane-induced preconditioning may involve release of free radicals. Methods Sixty-one alpha-chloralose-anesthetized rabbits were instrumented for measurement of left ventricular (LV) pressure (tip-manometer), cardiac output (ultrasonic flowprobe), and myocardial infarct size (triphenyltetrazolium staining). All rabbits were subjected to 30 min of occlusion of a major coronary artery and 2 h of subsequent reperfusion. Rabbits of all six groups underwent a treatment period consisting of either no intervention for 35 min (control group, n = 11) or 15 min of isoflurane inhalation (1 minimum alveolar concentration end-tidal concentration) followed by a 10-min washout period (isoflurane group, n = 12). Four additional groups received the radical scavenger N-(2-mercaptoproprionyl)glycine (MPG; 1 mg. kg-1.min-1) or Mn(III)tetrakis(4-benzoic acid)porphyrine chloride (MnTBAP; 100 microg.kg-1.min-1) during the treatment period with (isoflurane + MPG; n = 11; isoflurane + MnTBAP, n = 9) or without isoflurane inhalation (MPG, n = 11; MnTBAP, n = 7). Results Hemodynamic baseline values were not significantly different between groups (LV pressure, 97 +/- 17 mmHg [mean +/- SD]; cardiac output, 228 +/- 61 ml/min). During coronary artery occlusion, LV pressure was reduced to 91 +/- 17% of baseline and cardiac output to 94 +/- 21%. After 2 h of reperfusion, recovery of LV pressure and cardiac output was not significantly different between groups (LV pressure, 83 +/- 20%; cardiac output, 86 +/- 23% of baseline). Infarct size was reduced from 49 +/- 17% of the area at risk in controls to 29 +/- 19% in the isoflurane group (P = 0.04). MPG and MnTBAP themselves had no effect on infarct size (MPG, 50 +/- 14%; MnTBAP, 56 +/- 15%), but both abolished the preconditioning effect of isoflurane (isoflurane + MPG, 50 +/- 24%, P = 0.02; isoflurane + MnTBAP, 55 +/- 10%, P = 0.001). Conclusion Isoflurane-induced preconditioning depends on the release of free radicals.

1999 ◽  
Vol 91 (5) ◽  
pp. 1437-1437 ◽  
Author(s):  
Wolfgang G. Toller ◽  
Judy R. Kersten ◽  
Paul S. Pagel ◽  
Douglas A. Hettrick ◽  
David C. Warltier

Background Recent evidence indicates that volatile anesthetics exert protective effects during myocardial ischemia and reperfusion. The authors tested the hypothesis that sevoflurane decreases myocardial infarct size by activating adenosine triphosphate-sensitive potassium (K(ATP)) channels and reduces the time threshold of ischemic preconditioning necessary to protect against infarction. Methods Barbiturate-anesthetized dogs (n = 75) were instrumented for measurement of aortic and left ventricular pressures and maximum rate of increase of left ventricular pressure and were subjected to a 60-min left anterior descending (LAD) coronary artery occlusion followed by 3-h reperfusion. In four separate groups, dogs received vehicle or the K(ATP) channel antagonist glyburide (0.1 mg/kg intravenously), and 1 minimum alveolar concentration sevoflurane (administered until immediately before coronary artery occlusion) in the presence or absence of glyburide. In three additional experimental groups, sevoflurane was discontinued 30 min (memory) before the 60-min LAD occlusion or a 2-min LAD occlusion as an ischemic preconditioning stimulus was used with or without subsequent sevoflurane (with memory) pretreatment. Regional myocardial perfusion and infarct size were measured with radioactive microspheres and triphenyltetrazolium staining, respectively. Results Vehicle (23 +/- 1% of the area at risk; mean +/- SEM) and glyburide (23 +/- 2%) alone produced equivalent effects on myocardial infarct size. Sevoflurane significantly (P < 0.05) decreased infarct size (13 +/- 2%). This beneficial effect was abolished by glyburide (21 +/- 3%). Neither the 2-min LAD occlusion nor sevoflurane followed by 30 min of memory were protective alone, but together, sevoflurane enhanced the effects of the brief ischemic stimulus and profoundly reduced infarct size (9 +/- 2%). Conclusion Sevoflurane reduces myocardial infarct size by activating K(ATP) channels and reduces the time threshold for ischemic preconditioning independent of hemodynamic effects in vivo.


2004 ◽  
Vol 100 (3) ◽  
pp. 555-561 ◽  
Author(s):  
Dirk Ebel ◽  
Jost Müllenheim ◽  
Hendrik Südkamp ◽  
Thomas Bohlen ◽  
Jan Ferrari ◽  
...  

Background Short administration of volatile anesthetics preconditions myocardium and protects the heart against the consequences of subsequent ischemia. Activation of tyrosine kinase is implicated in ischemic preconditioning. The authors investigated whether desflurane-induced preconditioning depends on activation of tyrosine kinase. Methods Sixty-four rabbits were instrumented for measurement of left ventricular pressure, cardiac output, and myocardial infarct size (IS). All rabbits were subjected to 30 min of occlusion of a major coronary artery and 2 h of subsequent reperfusion. Rabbits underwent a treatment period consisting of either no intervention for 35 min (control group, n = 12) or 15 min of 1 minimum alveolar concentration desflurane inhalation followed by a 10-min washout period (desflurane group, n = 12). Four additional groups received the tyrosine kinase inhibitor genistein (5 mg/kg) or lavendustin A (1.3 mg/kg) at the beginning of the treatment period with (desflurane-genistein group, n = 11; desflurane-lavendustin A group, n = 12) or without desflurane inhalation (genistein group, n = 9; lavendustin A group, n = 8). Results Hemodynamic values were similar in all groups during baseline (left ventricular pressure, 87 +/- 14 mmHg (mean +/- SD]; cardiac output, 198 +/- 47 ml/min), during coronary artery occlusion (left ventricular pressure, 78 +/- 12 mmHg; cardiac output, 173 +/- 39 ml/min), and after 2 h of reperfusion (left ventricular pressure, 59 +/- 17; cardiac output, 154 +/- 43 ml/min). IS in the control group was 55 +/- 10% of the area at risk. The tyrosine inhibitors had no effect on IS (genistein group, 56 +/- 13%; lavendustin A group, 49 +/- 13%; each P = 1.0 vs. control group). Desflurane preconditioning reduced IS to 40 +/- 15% (P = 0.04 vs. control group). Tyrosine kinase inhibitor administration had no effect on IS reduction (desflurane-genistein group, 44 +/- 13%; desflurane-lavendustin A group, 44 +/- 16%; each P = 1.0 vs. desflurane group). Conclusion Desflurane-induced preconditioning does not depend on tyrosine kinase activation.


2001 ◽  
Vol 94 (4) ◽  
pp. 630-636 ◽  
Author(s):  
Jost Müllenheim ◽  
Jan Fräßdorf ◽  
Benedikt Preckel ◽  
Volker Thämer ◽  
Wolfgang Schlack

Background Ketamine blocks KATP channels in isolated cells and abolishes the cardioprotective effect of ischemic preconditioning in vitro. The authors investigated the effects of ketamine and S(+)-ketamine on ischemic preconditioning in the rabbit heart in vivo. Methods In 46 alpha-chloralose-anesthetized rabbits, left ventricular pressure (tip manometer), cardiac output (ultrasonic flow probe), and myocardial infarct size (triphenyltetrazolium staining) at the end of the experiment were measured. All rabbits were subjected to 30 min of occlusion of a major coronary artery and 2 h of subsequent reperfusion. The control group underwent the ischemia-reperfusion program without preconditioning. Ischemic preconditioning was elicited by 5-min coronary artery occlusion followed by 10 min of reperfusion before the 30 min period of myocardial ischemia (preconditioning group). To test whether ketamine or S(+)-ketamine blocks the preconditioning-induced cardioprotection, each (10 mg kg(-1)) was administered 5 min before the preconditioning ischemia. To test any effect of ketamine itself, ketamine was also administered without preconditioning at the corresponding time point. Results Hemodynamic baseline values were not significantly different between groups [left ventricular pressure, 107 +/- 13 mmHg (mean +/- SD); cardiac output, 183 +/- 28 ml/min]. During coronary artery occlusion, left ventricular pressure was reduced to 83 +/- 14% of baseline and cardiac output to 84 +/- 19%. After 2 h of reperfusion, functional recovery was not significantly different among groups (left ventricular pressure, 77 +/- 19%; cardiac output, 86 +/- 18%). Infarct size was reduced from 45 +/- 16% of the area at risk in controls to 24 +/- 17% in the preconditioning group (P = 0.03). The administration of ketamine had no effect on infarct size in animals without preconditioning (48 +/- 18%), but abolished the cardioprotective effects of ischemic preconditioning (45 +/- 19%, P = 0.03). S(+)-ketamine did not affect ischemic preconditioning (25 +/- 11%, P = 1.0). Conclusions Ketamine, but not S(+)-ketamine blocks the cardioprotective effect of ischemic preconditioning in vivo.


2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Jingyuan Li ◽  
Negar Motayagheni ◽  
Neusha Barakati ◽  
Mansoureh Eghbali

The prevalence of coronary artery disease in late pregnancy (LP) has increased recently due to significant changes in women’s lifestyle patterns (age, stress, smoking, diabetes and chronic hypertension). Myocardial infarction during LP and the peripartum is associated with significant maternal mortality and morbidity compared to non pregnant women for unclear reasons. We have recently demonstrated that cardiac vulnerability to I/R injury drastically increases in LP rodents, leading to myocardial infarct size ~4 fold greater than in non-pregnant controls. We also discovered that administration of intralipid (an emulsion of soy bean oil, egg yolk phospholipids and glycerol) at reperfusion resulted in ~60% reduction in infarct size of the heart in LP rat subjected to I/R injury. However, the molecular mechanisms underlying intralipid-induced cardioprotection in late pregnancy is not clear. Here we hypothesized that intralipid protects the heart in late pregnancy by regulating the levels of specific microRNAs. The left anterior descending coronary artery was occluded in LP rats (21-22 days of pregnancy) for 45 min followed by 3 hr of reperfusion. One single bolus of PBS (control group) or 20% intralipid (intralipid group) was applied through the femoral vein 5 min before the reperfusion. The hearts of control and intralipid groups were used for microRNA microarray analysis (Ocean Ridge Biosciences). MicroRNA-microarray analysis identified MiR122 as a novel micro-RNA which its expression was strikingly upregulated more than 10 fold in the heart of LP rats in intralipid group compared to control group. miR122 regulates apoptosis in cardiomyocytes subjected to hypoxia/reoxygenation since miR122-overexpression resulted in reduced apoptosis, whereas knockdown of miR122 enhanced apoptosis. Pyruvate kinase isoform M2 (PKM2), which is known to regulate cell apoptosis in the liver, is a direct target of miR122. Our data show that PKM2 and caspase 3 are two targets of miR122 since the expression of PKM2 and capase-3 in the heats subjected to I/R was significantly lower in intralipid group compared to control group in LP. In conclusion intralipid protects the heart in late pregnancy against ischemia/reperfusion injury via inducing miR122 by targeting PKM2.


1989 ◽  
Vol 257 (6) ◽  
pp. H1798-H1803 ◽  
Author(s):  
N. Uemura ◽  
D. R. Knight ◽  
Y. T. Shen ◽  
J. Nejima ◽  
M. V. Cohen ◽  
...  

Effects of permanent left circumflex coronary artery occlusion (CAO) were examined in conscious purebred beagles and mongrel dogs, instrumented with miniature left ventricular (LV) pressure gauges, wall thickness gauges in the ischemic zone, catheters in left atrium and aorta, and snares around the left circumflex coronary artery. Blood flow was measured using the radioactive microsphere technique before CAO and at 5 min, 1, 3, and 24 h after CAO. Although CAO reduced myocardial blood flow similarly in beagles and mongrels, significantly less (P less than 0.05) recovery of myocardial blood flow was observed over the following 24-h period in beagles. Infarct size, as determined by triphenyltetrazolium chloride and expressed as percentage of area at risk, was larger (P less than 0.05) in beagles (62.0 +/- 5.1%) than mongrels (42.5 +/- 4.2%). Thus beagles do not tolerate ischemia as well as mongrel dogs and possess fewer functional coronary collaterals resulting in larger infarcts after CAO.


Author(s):  
Hilde Karlsen ◽  
Harald Arne Bergan ◽  
Per Steinar Halvorsen ◽  
Kjetil Sunde ◽  
Eirik Qvigstad ◽  
...  

Abstract Background The effectiveness of adrenaline during resuscitation continues to be debated despite being recommended in international guidelines. There is evidence that the β-adrenergic receptor (AR) effects of adrenaline are harmful due to increased myocardial oxygen consumption, post-defibrillation ventricular arrhythmias and increased severity of post-arrest myocardial dysfunction. Esmolol may counteract these unfavourable β-AR effects and thus preserve post-arrest myocardial function. We evaluated whether a single dose of esmolol administered prior to adrenaline preserves post-arrest cardiac output among successfully resuscitated animals in a novel, ischaemic cardiac arrest porcine model. Methods Myocardial infarction was induced in 20 anaesthetized pigs by inflating a percutaneous coronary intervention (PCI) balloon in the circumflex artery 15 min prior to induction of ventricular fibrillation. After 10 min of untreated VF, resuscitation with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) was initiated and the animals were randomized to receive an injection of either 1 mg/kg esmolol or 9 mg/ml NaCl, prior to adrenaline. Investigators were blinded to allocation. Successful defibrillation was followed by a 1-h high-flow VA-ECMO before weaning and an additional 1-h stabilization period. The PCI-balloon was deflated 40 min after inflation. Cardiac function pre- and post-arrest (including cardiac output) was assessed by magnetic resonance imaging (MRI) and invasive pressure measurements. Myocardial injury was estimated with MRI, triphenyl tetrazolium chloride (TTC) staining and serum concentrations of cardiac troponin T. Results Only seven esmolol and five placebo-treated pigs were successfully resuscitated and available for post-arrest measurements (p = 0.7). MRI revealed severe but similar reductions in post-arrest cardiac function with cardiac output 3.5 (3.3, 3.7) and 3.3 (3.2, 3.9) l/min for esmolol and control (placebo) groups, respectively (p = 0.7). The control group had larger left ventricular end-systolic and end-diastolic ventricular volumes compared to the esmolol group (75 (65, 100) vs. 62 (53, 70) ml, p = 0.03 and 103 (86, 124) vs. 87 (72, 91) ml, p = 0.03 for control and esmolol groups, respectively). There were no other significant differences in MRI characteristics, myocardial infarct size or other haemodynamic measurements between the two groups. Conclusions We observed similar post-arrest cardiac output with and without a single dose of esmolol prior to adrenaline administration during low-flow VA-ECMO in an ischaemic cardiac arrest pig model.


1995 ◽  
Vol 269 (4) ◽  
pp. H1460-H1466 ◽  
Author(s):  
R. D. Lasley ◽  
P. J. Konyn ◽  
J. O. Hegge ◽  
R. M. Mentzer

The accumulation of adenosine during a brief coronary occlusion has been proposed to mediate the infarct size-limiting effect of ischemic preconditioning. The purpose of this study was to compare the effects of ischemic preconditioning and a transient adenosine infusion on myocardial interstitial fluid (ISF) adenosine levels and infarct size. Microdialysis fibers (10.0 mm length) were placed in the left ventricular myocardium of pentobarbital sodium-anesthetized rabbits to estimate ISF adenosine. Ischemic preconditioning was induced by 5 min of coronary artery occlusion and 10 min of reperfusion before 45 min of occlusion. Adenosine preconditioning was induced with 5 min of intravenous adenosine infusion (140 micrograms.kg-1.min-1) followed by a 10-min washout before the prolonged occlusion. Myocardial infarct size was determined by triphenyltetrazolium chloride staining after 3 h of reperfusion. Five minutes of ischemia and 5 min of adenosine infusion produced comparable increases in dialysate adenosine levels (from 0.19 +/- 0.02 to 0.69 +/0- 0.11 and 0.28 +/- 0.10 to 0.71 +/- 0.18 microM, respectively) that decreased to baseline before the prolonged ischemia; however, ischemic-preconditioned hearts exhibited elevated dialysate adenosine levels for the first 5 min of reperfusion. Ischemic-preconditioned hearts exhibited significantly reduced dialysate adenosine concentrations for the first 20 min of the prolonged occlusion (P < 0.05 vs. control), and infarct size was reduced from 41 +/- 6 to 10 +/- 4% of risk area. Adenosine preconditioning had no effect on dialysate adenosine levels during prolonged ischemia but did reduce infarct size to 25 +/- 5% of risk area. These results indicate that a transient increase in ISF adenosine can reduce myocardial infarct size, but adenosine alone does not fully replicate the protective effects of ischemic preconditioning.


1996 ◽  
Vol 270 (5) ◽  
pp. H1744-H1756 ◽  
Author(s):  
M. Kitakaze ◽  
T. Minamino ◽  
K. Node ◽  
K. Komamura ◽  
Y. Shinozaki ◽  
...  

We tested the hypothesis that the opening of ATP-sensitive K+ channels contributes to activation of ectosolic 5'-nucleotidase and the infarct size-limiting effect of ischemic preconditioning. In open-chest dogs, the left anterior descending coronary artery was occluded four times for 5 min each, separated by a 5-min period of reperfusion (ischemic preconditioning, n = 8). After this procedure, the coronary artery was occluded for 90 min, followed by 6 h of reperfusion. Infarct size was smaller in this group than in the group (control, n = 8) with a 45 min interval instead of the ischemic preconditioning procedure (40.1 +/- 3.9 vs. 6.4 +/- 1.9%). Glibenclamide blunted the infarct size-limiting effect of ischemic preconditioning (infarct size, 37.3 +/- 5.8%; n = 7), and transient exposures to cromakalim and nicorandil mimicked it [infarct size, 10.1 +/- 3.1 (n = 7) and 11.1 +/- 2.7% (n = 8), respectively]. Ectosolic and cytosolic 5'-nucleotidase activity increased in the ischemic preconditioning group compared with that in the control group; this preconditioning-induced increase in 5'-nucleotidase activity was blunted by glibenclamide (n = 5) and mimicked by cromakalim (n = 5) and nicorandil (n = 5). The infarct size-limiting effect due to cromakalim and nicorandil was blunted by alpha,beta-methyleneadenosine 5'-diphosphate, an inhibitor of ectosolic 5'-nucleotidase [infarct size, 37.7 +/- 5.6 (n = 9) and 36.8 +/- 4.8% (n = 7), respectively] and 8-sulfophenyltheophylline (infarct size with cromakalim, 44.7 +/- 4.6%; n = 7). We conclude that activation of ectosolic 5'-nucleotidase due to the openers of ATP-sensitive K+ channels contributes to the infarct size- limiting effect of ischemic preconditioning.


1999 ◽  
Vol 276 (6) ◽  
pp. H2029-H2034 ◽  
Author(s):  
Sharon L. Hale ◽  
Robert A. Kloner

This study tests whether combining regional hypothermia and ischemic preconditioning (IP) provides greater myocardial protection during prolonged coronary artery occlusion (CAO) than either intervention alone, and whether increasing the duration of IP from 5 to 7 min extends the window of protection to include a 2-h CAO. Anesthetized rabbits were randomized to four groups ( n = 8 rabbits/group): control (C), hypothermia alone (H), IP alone for two 7-min episodes (IP7), and IP plus hypothermia (H + IP7). To compare differences in IP for 5 versus 7 min, additional rabbits ( n = 6) received one 5-min episode of ischemia (IP5). All rabbits got 2 h of CAO and 3 h of reperfusion. In comparison with the infarct size in the control group (72 ± 4% of the risk zone), infarct size was significantly reduced in H (50 ± 7%), IP7 (49 ± 5%), and H + IP7 (42 ± 6%) (all P < 0.05 vs. control group). IP5 failed to confer protection (67 ± 5% of the risk zone). Therefore, IP can protect against a 2-h CAO if the IP regimen is increased from 5 to 7 min. The combination therapy significantly improved regional myocardial blood flow in the previously ischemic region to a greater extent than either treatment alone.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jichun Han ◽  
Dong Wang ◽  
Bacui Yu ◽  
Yanming Wang ◽  
Huanhuan Ren ◽  
...  

The generation of reactive oxygen species (ROS) is a major cause of heart injury induced by ischemia-reperfusion. The left ventricular developed pressure (LVDP) and the maximum up/down rate of left ventricular pressure (±dp/dtmax⁡) were documented by a physiological recorder. Myocardial infarct size was estimated macroscopically using 2,3,5-triphenyltetrazolium chloride staining. Coronary effluent was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK) release to assess the degree of cardiac injury. The levels of C-reactive protein (CRP), interleukin-8 (IL-8), tumor necrosis factor-α(TNF-α), and interleukin-6 (IL-6) were analyzed to determine the inflammation status of the myocardial tissue. Cardiomyocyte apoptosis analysis was performed using the In Situ Cell Death Detection Kit, POD. Accordingly, licochalcone B pretreatment improved the heart rate (HR), increased LVDP, and decreased CK and LDH levels in coronary flow. SOD level and GSH/GSSG ratio increased, whereas the levels of MDA, TNF-α, and CRP and activities of IL-8 and IL-6 decreased in licochalcone B-treated groups. The infarct size and cell apoptosis in hearts from licochalcone B-treated group were lower than those in hearts from the I/R control group. Therefore, the cardioprotective effects of licochalcone B may be attributed to its antioxidant, antiapoptotic, and anti-inflammatory activities.


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