Ceramide in the antiapoptotic effect of ischemic preconditioning

2004 ◽  
Vol 286 (1) ◽  
pp. H246-H251 ◽  
Author(s):  
Laurent Argaud ◽  
Annie-France Prigent ◽  
Lara Chalabreysse ◽  
Joseph Loufouat ◽  
Michel Lagarde ◽  
...  
Keyword(s):  
Infarct Size ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Kinase Assay ◽  
Control Group ◽  
Blue Dye ◽  
Triphenyltetrazolium Chloride ◽  
Antiapoptotic Effect ◽  
Ceramide Production

Although the mechanism by which ischemic preconditioning (PC) inhibits myocardial apoptosis during ischemia-reperfusion is unclear, evidence indicates a role for the secondary messenger ceramide. We investigated in vivo whether PC may affect ceramide and sn-1,2-diacylglycerol (DAG) production, and attenuate apoptosis during ischemia. Rabbits underwent 30 min of ischemia, followed by 4 h of reperfusion. Before this, they received either no intervention (control group) or one episode of 5 min of ischemia, followed by 5 min of reperfusion (PC group), or an intravenous administration of the sphingomyelinase inhibitor D609. Myocardial content of ceramide and DAG was measured using the DAG kinase assay at different time points of the experiment. Apoptosis was detected and quantified by a sandwich enzyme immunoassay. Both AR and infarct size were measured using blue dye injection and triphenyltetrazolium chloride staining. Control hearts exhibited a peak of ceramide production at 5 min of the prolonged ischemia, with a mean value averaging 64 ± 5 ng/mg tissue ( P < 0.05 vs. 48 ± 4 ng/mg at baseline). In contrast, ischemic PC and D609 prevented ceramide increase during the prolonged ischemia. Myocardial DAG content was increased only in PC hearts at 30 min of ischemia. Preconditioned and D609 groups developed less apoptosis, as well as a limited infarct size, compared with the control group. These results suggest that the antiapoptotic effect of PC may be due to a reduced ceramide production during sustained ischemia in the rabbit heart.

Increased mitochondrial calcium coexists with decreased reperfusion injury in postconditioned (but not preconditioned) hearts

2008 ◽  
Vol 294 (1) ◽  
pp. H386-H391 ◽  
Author(s):  
Laurent Argaud ◽  
Odile Gateau-Roesch ◽  
Lionel Augeul ◽  
Elisabeth Couture-Lepetit ◽  
Joseph Loufouat ◽  
...  
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Control Group ◽  
Blue Dye ◽  
Mitochondrial Calcium ◽  
Area At Risk ◽  
Triphenyltetrazolium Chloride ◽  
Pore Opening

Ca2+ is the main trigger for mitochondrial permeability transition pore opening, which plays a key role in cardiomyocyte death after ischemia-reperfusion. We investigated whether a reduced accumulation of mitochondrial Ca2+ might explain the attenuation of lethal reperfusion injury by postconditioning. Anesthetized New Zealand White rabbits underwent 30 min of ischemia, followed by either 240 (infarct size protocol) or 60 (mitochondria protocol) min of reperfusion. They received either no intervention (control), preconditioning by 5-min ischemia and 5-min reperfusion, postconditioning by four cycles of 1-min reperfusion and 1-min ischemia at the onset of reflow, or pharmacological inhibition of the transition pore opening by N-methyl-4-isoleucine-cyclosporin (NIM811; 5 mg/kg iv) given at reperfusion. Area at risk and infarct size were assessed by blue dye injection and triphenyltetrazolium chloride staining. Mitochondria were isolated from the risk region for measurement of 1) Ca2+ retention capacity (CRC), and 2) mitochondrial content of total (atomic absorption spectrometry) and ionized (potentiometric technique) calcium concentration. CRC averaged 0.73 ± 0.16 in control vs. 4.23 ± 0.17 μg Ca2+/mg proteins in shams ( P < 0.05). Postconditioning, preconditioning, or NIM811 significantly increased CRC ( P < 0.05 vs. control). In the control group, total and free mitochondrial calcium significantly increased to 2.39 ± 0.43 and 0.61 ± 0.10, respectively, vs. 1.42 ± 0.09 and 0.16 ± 0.01 μg Ca2+/mg in sham ( P < 0.05). Surprisingly, whereas total and ionized mitochondrial Ca2+ decreased in preconditioning, it significantly increased in postconditioning and NIM811 groups. These data suggest that retention of calcium within mitochondria may explain the decreased reperfusion injury in postconditioned (but not preconditioned) hearts.

Isoflurane Mimics Ischemic Preconditioning via Activation of KATPChannels 

1997 ◽  
Vol 87 (2) ◽  
pp. 361-370 ◽  
Author(s):  
Judy R. Kersten ◽  
Todd J. Schmeling ◽  
Paul S. Pagel ◽  
Garrett J. Gross ◽  
David C. Warltier
Keyword(s):  
Infarct Size ◽  
Ischemic Preconditioning ◽  
Myocardial Infarct ◽  
Myocardial Infarct Size ◽  
Protective Effects ◽  
Hemodynamic Effects ◽  
Area At Risk ◽  
Triphenyltetrazolium Chloride ◽  
Anesthetized Dogs

Background The authors tested the hypothesis that isoflurane directly preconditions myocardium against infarction via activation of K(ATP) channels and that the protection afforded by isoflurane is associated with an acute memory phase similar to that of ischemic preconditioning. Methods Barbiturate-anesthetized dogs (n = 71) were instrumented for measurement of systemic hemodynamics. Myocardial infarct size was assessed by triphenyltetrazolium chloride staining. All dogs were subjected to a single prolonged (60 min) left anterior descending coronary artery (LAD) occlusion followed by 3 h of reperfusion. Ischemic preconditioning was produced by four 5-min LAD occlusions interspersed with 5-min periods of reperfusion before the prolonged LAD occlusion and reperfusion. The actions of isoflurane to decrease infarct size were examined in dogs receiving 1 minimum alveolar concentration (MAC) isoflurane that was discontinued 5 min before prolonged LAD occlusion. The interaction between isoflurane and ischemic preconditioning on infarct size was evaluated in dogs receiving isoflurane before and during preconditioning LAD occlusions and reperfusions. To test whether the cardioprotection produced by isoflurane can mimic the acute memory of ischemic preconditioning, isoflurane was discontinued 30 min before prolonged LAD occlusion and reperfusion. The mechanism of isoflurane-induced cardioprotection was evaluated in two final groups of dogs pretreated with glyburide in the presence or absence of isoflurane. Results Myocardial infarct size was 25.3 +/- 2.9% of the area at risk during control conditions. Isoflurane and ischemic preconditioning produced significant (P &lt; 0.05) and equivalent reductions in infarct size (ischemic preconditioning alone, 9.6 +/- 2.0; isoflurane alone, 11.8 +/- 2.7; isoflurane and ischemic preconditioning, 5.1 +/- 1.9%). Isoflurane-induced reduction of infarct size also persisted 30 min after discontinuation of the anesthetic (13.9 +/- 1.5%), independent of hemodynamic effects during LAD occlusion. Glyburide alone had no effect on infarct size (28.3 +/- 3.9%), but it abolished the protective effects of isoflurane (27.1 +/- 4.6%). Conclusions Isoflurane directly preconditions myocardium against infarction via activation of K(ATP) channels in the absence of hemodynamic effects and exhibits acute memory of preconditioning in vivo.

Ischemic preconditioning and morphine attenuate myocardial apoptosis and infarction after ischemia-reperfusion in rabbits: role of δ-opioid receptor

2004 ◽  
Vol 287 (4) ◽  
pp. H1786-H1791 ◽  
Author(s):  
Shinji Okubo ◽  
Yujirou Tanabe ◽  
Kenji Takeda ◽  
Michihiko Kitayama ◽  
Seiyu Kanemitsu ◽  
...  
Keyword(s):  
Infarct Size ◽  
Opioid Receptor ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Control Group ◽  
Apoptotic Cells ◽  
Protective Effects ◽  
Δ Opioid Receptor

We examined whether ischemic preconditioning (IPC) attenuates ischemia-reperfusion injury, in part, by decreasing apoptosis and whether the δ-opioid receptor (DOR) plays a pivotal role in the regulation of apoptosis. Rabbits were subjected to 30-min coronary artery occlusion (CAO) and 180 min of reperfusion. IPC was elicited with four cycles of 5-min ischemia and 10-min reperfusion before CAO. Morphine (0.3 mg/kg iv) was given 15 min before CAO. Naloxone (Nal; 10 mg/kg iv) and naltrindole (Nti; 10 mg/kg iv), the respective nonselective and selective DOR antagonists were given 10 min before either morphine or IPC. Infarct size (%risk area) was reduced from 46 ± 3.8 in control to 11.6 ± 1.0 in IPC and 19.5 ± 3.8 in the morphine group (means ± SE; P < 0.001 vs. control). Nal blocked the protective effects of IPC and morphine, as shown by the increase in infarct size to 38.6 ± 7.2 and 44.5 ± 1.8, respectively. Similarly, Nti blocked IPC and morphine-induced protection. The percentage of apoptotic cells (revealed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay) decreased in IPC (3.6 ± 1.9) and morphine groups (5.2 ± 1.2) compared with control group (12.4 ± 1.6; P < 0.001). Nti pretreatment increased apoptotic cells 11.2 ± 2.2% in IPC and 12.1 ± 0.8% in morphine groups. Nal failed to block inhibition of apoptosis in the IPC group (% of cells: 5.7 ± 1.3 vs. 3.6 ± 1.9 in IPC alone; P > 0.05). These results were also confirmed by nucleosomal DNA laddering pattern. We conclude that IPC reduces lethal injury, in part, by decreasing apoptosis after ischemia-reperfusion and activation of the DOR may play a crucial role in IPC or morphine-induced myocardial protection.

scholarly journals Cardioprotective Effect of Novel Matrix Metalloproteinase Inhibitors

2020 ◽  
Vol 21 (19) ◽  
pp. 6990
Author(s):  
Kamilla Gömöri ◽  
Tamara Szabados ◽  
Éva Kenyeres ◽  
Judit Pipis ◽  
Imre Földesi ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Positive Control ◽  
Matrix Metalloproteinase 2 ◽  
Area At Risk ◽  
Triphenyltetrazolium Chloride

Background: We recently developed novel matrix metalloproteinase-2 (MMP-2) inhibitor small molecules for cardioprotection against ischemia/reperfusion injury and validated their efficacy in ischemia/reperfusion injury in cardiac myocytes. The aim of the present study was to test our lead compounds for cardioprotection in vivo in a rat model of acute myocardial infarction (AMI) in the presence or absence of hypercholesterolemia, one of the major comorbidities affecting cardioprotection. Methods: Normocholesterolemic adult male Wistar rats were subjected to 30 min of coronary occlusion followed by 120 min of reperfusion to induce AMI. MMP inhibitors (MMPI)-1154 and -1260 at 0.3, 1, and 3 µmol/kg, MMPI-1248 at 1, 3, and 10 µmol/kg were administered at the 25th min of ischemia intravenously. In separate groups, hypercholesterolemia was induced by a 12-week diet (2% cholesterol, 0.25% cholic acid), then the rats were subjected to the same AMI protocol and single doses of the MMPIs that showed the most efficacy in normocholesterolemic animals were tested in the hypercholesterolemic animals. Infarct size/area at risk was assessed at the end of reperfusion in all groups by standard Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining, and myocardial microvascular obstruction (MVO) was determined by thioflavine-S staining. Results: MMPI-1154 at 1 µmol/kg, MMPI-1260 at 3 µmol/kg and ischemic preconditioning (IPC) as the positive control reduced infarct size significantly; however, this effect was not seen in hypercholesterolemic animals. MVO in hypercholesterolemic animals decreased by IPC only. Conclusions: This is the first demonstration that MMPI-1154 and MMPI-1260 showed a dose-dependent infarct size reduction in an in vivo rat AMI model; however, single doses that showed the most efficacy in normocholesterolemic animals were abolished by hypercholesterolemia. The further development of these promising cardioprotective MMPIs should be continued with different dose ranges in the study of hypercholesterolemia and other comorbidities.

Cardioprotective effect of rosuvastatin in vivo is dependent on inhibition of geranylgeranyl pyrophosphate and altered RhoA membrane translocation

2007 ◽  
Vol 292 (6) ◽  
pp. H3158-H3163 ◽  
Author(s):  
Aliaksandr Bulhak ◽  
Joy Roy ◽  
Ulf Hedin ◽  
Per-Ove Sjöquist ◽  
John Pernow
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardioprotective Effect ◽  
Control Group ◽  
Geranylgeranyl Pyrophosphate ◽  
Rhoa Protein ◽  
Coa Reductase

Hydroxymethyl glutaryl (HMG)-coenzyme A (CoA) reductase inhibitors (statins) protect the myocardium against ischemia-reperfusion injury via a mechanism unrelated to cholesterol lowering. Statins may inhibit isoprenylation and thereby prevent activation of proteins such as RhoA. We hypothesized that statins protect the myocardium against ischemia-reperfusion injury via a mechanism involving inhibition of geranylgeranyl pyrophosphate synthesis and translocation of RhoA to the plasma membrane. Sprague-Dawley rats were given either the HMG-CoA reductase inhibitor rosuvastatin, geranylgeranyl pyrophosphate dissolved in methanol, the combination of rosuvastatin and geranylgeranyl pyrophosphate, rosuvastatin and methanol, or distilled water (control) by intraperitoneal injection for 48 h before ischemia-reperfusion. Animals were anesthetized and either subjected to 30 min of coronary artery occlusion followed by 2 h of reperfusion whereat infarct size was determined, or the expression of RhoA protein was determined in cytosolic and membrane fractions of nonischemic myocardium. There were no significant differences in hemodynamics between the control group and the other groups before ischemia or during ischemia and reperfusion. The infarct size was 80 ± 3% of the area at risk in the control group. Rosuvastatin reduced infarct size to 64 ± 2% ( P < 0.001 vs. control). Addition of geranylgeranyl pyrophosphate (77 ± 2%, P < 0.01 vs. rosuvastatin) but not methanol (65 ± 2%, not significant vs. rosuvastatin) abolished the cardioprotective effect of rosuvastatin. Geranylgeranyl pyrophosphate alone did not affect infarct size per se (84 ± 2%). Rosuvastatin increased the cytosol-to-membrane ratio of RhoA protein in the myocardium ( P < 0.05 vs. control). These changes were abolished by addition of geranylgeranyl pyrophosphate. We conclude that the cardioprotection and the increase of the RhoA cytosol-to-membrane ratio induced by rosuvastatin in vivo are blocked by geranylgeranyl pyrophosphate. The inhibition of geranylgeranyl pyrophosphate formation and subsequent modulation of cytosol/membrane-bound RhoA are of importance for the protective effect of statins against myocardial ischemia-reperfusion injury.

scholarly journals Comparative Effects of Verapamil, Nicardipine, and Nitroglycerin on Myocardial Ischemia/Reperfusion Injury

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Hitoshi Yui ◽  
Uno Imaizumi ◽  
Hisashi Beppu ◽  
Mitsuhiro Ito ◽  
Munetaka Furuya ◽  
...  
Keyword(s):  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Rabbit Model ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Control Group ◽  
Area At Risk ◽  
Group A

The aim of this experiment was to establish whether verapamil, nicardipine, and nitroglycerin have (1) infarct size-limiting effects and (2) antiarrhythmic effects inin vivorabbit hearts during ischemia/reperfusion. Rabbits received regional ischemia by 30 min of left anterior descending coronary artery occlusion followed by 3 hours of reperfusion under ketamine and xylazine anesthesia. The animals were randomly assigned to the following 4 treatment groups: a control group, a verapamil group, a nicardipine group, and a nitroglycerin group. A continuous infusion of verapamil, nicardipine, or nitroglycerin was initiated 5 min prior to ischemia. Infarct size/area at risk decreased in verapamil, and nitroglycerin. The incidence of ischemia-induced arrhythmia decreased in nicardipine, verapamil and nitroglycerin. The incidence of reperfusion-induced arrhythmias decreased in verapamil and nitroglycerin. From the present experimental results, verapamil and nitroglycerin rather than nicardipine did afford significant protection to the heart subjected to ischemia and reperfusion in a rabbit model.

Abstract 411: Endogenous miRNA Induced By Ischemic Preconditioning Reduces Myocardial Infarct Size following Ischemia/Reperfusion In Mice

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Chang Yin ◽  
Fadi N Salloum ◽  
Rakesh C Kukreja
Keyword(s):  
Infarct Size ◽  
Ischemic Preconditioning ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Protective Role ◽  
Coronary Artery Ligation ◽  
Myocardial Infarct Size ◽  
Artery Ligation ◽  
Buffer Control

BACKGROUND: Due to its short length (~24 nt) and non-coding nature, microRNA (miRNA) used to be regarded as “evolutionary transcriptional debris”. Recent evidence suggests that miRNA is a novel regulator for transcription and translation. It is known that brief episodes of ischemia during ischemic preconditioning (IPC) trigger complex genetic pro-survival program that results in modulation of several key proteins involved in protection against I/R injury. We hypothesized that miRNA synthesized during IPC is the potential mediator of such protection. METHODS / RESULTS : Hearts were isolated from 3 groups (n = 6/group) of adult ICR mice and subjected to the following treatments in Langendorff mode: 120 min of perfusion with Krebs-Henseleit buffer (control); 30 min global ischemia followed by 1 hr reperfusion (I/R); 2 cycles of 30 sec ischemia and 90 sec reperfusion followed by 30 min ischemia and 1 hr reperfusion (IPC). Infarct size (IS) was measured by triphenyl tetrazolium staining. IPC in the Langendorff model reduced IS from 29.7 ± 2.1% in the I/R hearts to 9.1 ± 1.8 % in the IPC group. This protection was associated with a significant induction of miRNA-1 (162 ± 13%), miRNA-21 (118 ± 6%), and miRNA-24 (46 ± 12%). To test its protective role, miRNA was extracted from 6 hearts following the IPC protocol; and then injected in vivo into the left ventricle wall in another group of 6 mice. Forty-eight hrs later, these mice were subjected to I/R injury in vivo by left coronary artery ligation for 30 min followed by reperfusion for 24 hr. In addition, a subset of mice was treated with miRNA inhibitors (methylated antisense miRNA) in conjunction with miRNA from IPC hearts. The results show that miRNA extracted from the IPC hearts reproduced a protective phenotype with significantly lower infarction (18.8 ± 2.5 %) in vivo as compared to saline-treated control (37.5 ± 2.2%). This protective effect was totally abolished by specific inhibitors of miRNA-1 and miRNA-21 (IS: 43.7 ± 2.1%). CONCLUSION : miRNA extracted from preconditioned hearts shows a protective role against I/R injury. The detection of miRNA in preconditioned hearts offers a novel strategy in cardioprotection. Further studies are needed to identify the gene targets by which miRNA generate protective phenotype.

Abstract 13914: Ischemic Preconditioning Induces MG53 Secretion From the Heart Through H 2 O 2 /PKC-delta Signaling

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Dan Shan ◽  
Yan Zhang ◽  
Rui-ping Xiao
Keyword(s):  
Ischemic Preconditioning ◽  
Cell Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Embryonic Stem ◽  
Underlying Mechanism ◽  
Neonatal Rat ◽  
Control Group ◽  
Systemic Delivery

Introduction: Ischemic heart disease is the leading cause of morbidity and mortality worldwide. Ischemic preconditioning (IPC) is the most powerful intrinsic protection against cardiac ischemia/reperfusion (I/R) injury. Previous studies have shown that a multifunctional TRIM family protein, MG53 (or TRIM72), not only plays an essential role in IPC-mediated cardioprotection, but also as a myokine/cardiokine, can be secreted from the heart and skeletal muscle in response to metabolic stress in addition to its intracellular actions. Hypothesis: We hypothesized that IPC-mediated cardioprotection is causally related to MG53 secretion and figured out the underlying mechanism. Methods and Results: Using proteomic analysis in conjunction with genetic and pharmacological approaches, we examined MG53 secretion in response to IPC and explored the underlying mechanism using rodents in in vivo , isolated perfused hearts, and cultured neonatal rat ventricular cardiomyocytes. IPC profoundly increased perfusate MG53 levels in mouse hearts by 5.50 ± 0.32 and 4.26 ± 0.40 folds from baseline over 0-60 and 60-120 min of reperfusion, respectively. Mechanistically, IPC-induced MG53 secretion is dependent on H 2 O 2 -evoked, Src-mediated phosphorylation of PKC-δ-Y311. Functionally, systemic delivery of recombinant human MG53 proteins (rhMG53) to mimic elevated circulating MG53 not only restored IPC function in MG53-deficient mice, but also protected rodent hearts from I/R injury even in the absence of IPC. Treatment of rhMG53 overtly decreased the infarct size (IF/AAR) induced by I/R compared to the BSA-treated control group (11.9 ± 1.8% vs 27.3 ± 2.0%, P <0.01), and reduced the mortality from 44.7% to 5.3% in rats. Moreover, H 2 O 2 augmented MG53 secretion, and MG53 knockdown exacerbated H 2 O 2 -induced cell injury in human embryonic stem cell-derived cardiomyocytes. Conclusions: In conclusion, IPC and oxidative stress can trigger MG53 secretion from the heart via an H 2 O 2 -PKC-δ-dependent mechanism, and secreted MG53 acts as an essential factor conveying IPC-induced cardioprotection against ischemia/reperfusion injury. Recombinant MG53 proteins can be developed into a novel treatment for various diseases of human heart in which the endogenous MG53 is low.

scholarly journals Smaller infarct after preconditioning does not predict extent of early functional improvement of reperfused heart

1999 ◽  
Vol 277 (5) ◽  
pp. H1754-H1761 ◽  
Author(s):  
Michael V. Cohen ◽  
Xi-Ming Yang ◽  
James M. Downey
Keyword(s):  
Infarct Size ◽  
Ischemic Preconditioning ◽  
Coronary Occlusion ◽  
Recovery Of Function ◽  
Systolic Function ◽  
Functional Improvement ◽  
Segment Length ◽  
Control Group ◽  
Triphenyltetrazolium Chloride ◽  
Ecg Leads

We evaluated the ability of ischemic preconditioning to restore function to salvaged myocardium in rabbits. Although ischemic preconditioning reduces infarct size, few investigators studying recovery of function after coronary occlusions lasting ≥30 min have reported any mechanical benefit in preconditioned hearts. However, because myocardial function was seldom evaluated beyond 5 h after reperfusion stunning may have masked the benefit. Accordingly, rabbits were chronically instrumented with a pneumatic occluder around a branch of the left coronary artery, a pair of 1-mm ultrasonic crystals in the myocardial territory destined to become ischemic, and electrocardiogram (ECG) leads. One week after surgery the ECG and segment length tracing were recorded at rest, during 30-min occlusion and 1 h of reflow, and again at 24, 48, and 72 h. In ischemically preconditioned rabbits, 5-min coronary occlusion and 10-min reperfusion preceded the long occlusion. The beginning and end of systole were determined by recording the first and second heart sounds with a hand-held precordial microphone. Postmortem infarct size was measured with triphenyltetrazolium chloride. During the 30-min coronary occlusion all segments became nearly akinetic or bulged during systole. After 60 min of reflow there was little return of function in either group. Between 24 and 72 h there was minimal recovery in the control group (segment shortening equals 13.3 ± 4.1% of baseline), whereas function was much better in preconditioned hearts (44.2 ± 7.4% of baseline, P < 0.02). Infarct size as a percentage of risk zone was much smaller in preconditioned hearts (10.2 ± 1.4 vs. 29.7 ± 1.8%, P < 0.001). Thus there is a gradual recovery of systolic function of reperfused myocardium after a coronary occlusion. Although early mechanical recovery is significantly better after preconditioning, it is much less than would be predicted by the reduction of infarct size.

Speckle tracking imaging improves in vivo assessment of EPO-induced myocardial salvage early after ischemia-reperfusion in rats

2010 ◽  
Vol 298 (6) ◽  
pp. H1679-H1686 ◽  
Author(s):  
Frederic Treguer ◽  
Erwan Donal ◽  
Sophie Tamareille ◽  
Nehmat Ghaboura ◽  
Geneviève Derumeaux ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Infarct Size ◽  
Rat Model ◽  
Speckle Tracking ◽  
Ischemia Reperfusion ◽  
Control Group ◽  
Myocardial Salvage ◽  
Speckle Tracking Imaging ◽  
Triphenyltetrazolium Chloride ◽  
Conventional Echocardiography

A noninvasive assessment of infarct size and transmural extension of myocardial infarction (TEMI) is fundamental in experimental models of ischemia-reperfusion. Conventional echocardiography parameters are limited in this purpose. This study was designed to examine whether speckle tracking imaging can be used in a rat model of ischemia-reperfusion to accurately detect the reduction of infarct size and TEMI induced by erythropoietin (EPO) as early as 24 h after reperfusion. Rats were randomly assigned to one of three groups: myocardial infarction (MI)-control group, 45 min ischemia followed by 24 h of reperfusion; MI-EPO group, similar surgery with a single bolus of EPO administered at the onset of reperfusion; and sham-operated group. Short-axis two-dimensional echocardiography was performed after reperfusion. Global radial (GSr) and circumferential (GScir) strains were compared with infarct size and TEMI assessed after triphenyltetrazolium chloride staining. As a result, ejection fraction, shortening fraction, GSr, and GScir significantly correlated to infarct size, whereas only GSr and GScir significantly correlated to TEMI. EPO significantly decreased infarct size (30.8 ± 3.5 vs. 56.2 ± 5.7% in MI-control, P < 0.001) and TEMI (0.37 ± 0.05 vs. 0.77 ± 0.05 in MI-control, P < 0.001). None of the conventional echocardiography parameters was significantly different between the MI-EPO and MI-control groups, whereas GSr was significantly higher in the MI-EPO group (29.1 ± 4.7 vs. 16.4 ± 3.3% in MI-control; P < 0.05). Furthermore, GScir and GSr appeared to be the best parameters to identify a TEMI >0.75 24 h after reperfusion. In conclusion, these findings demonstrate the usefulness of speckle tracking imaging in the early evaluation of a cardioprotective strategy in a rat model of ischemia-reperfusion.

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