Failure of Pharmacological Agents to Affect the Infarct Size/Area at Risk in The Canine Left Ventricle

1985 ◽  
Vol 69 (s12) ◽  
pp. 30P-30P
Author(s):  
M.J. Main ◽  
M.I.M. Noble ◽  
A.J. Drake-Holland ◽  
J. Hynd ◽  
K. Isted
Keyword(s):  
At Risk ◽  
Left Ventricle ◽  
Infarct Size ◽  
Area At Risk ◽  
Pharmacological Agents

Abstract 212: Cd4+ T-cell Activation By T-cell Receptor Engagement Contributes To Myocardial Ischemia-reperfusion Injury

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Ulrich Hofmann ◽  
Denise Mathes ◽  
Johannes Weirather ◽  
Niklas Beyersdorf ◽  
Thomas Kerkau ◽  
...  
Keyword(s):  
At Risk ◽  
T Cells ◽  
T Cell ◽  
Infarct Size ◽  
T Cell Receptor ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cell Receptor ◽  
Area At Risk ◽  
Infarct Area

Background: We have recently shown that CD4 + but not CD8 + T-cells contribute to ischemia-reperfusion injury of the myocardium. We therefore hypothesized that CD4 + T-cells become activated by autoantigen recognition via their T-cell receptor during reperfusion. Methods and Results: Infarct size as percent of the area-at-risk was determined by combined Evans` blue and triphenyltetrazolium (TTC) staining after 30 minutes of in vivo ischemia followed by 24 hours reperfusion in mice. After 24 hours of reperfusion there was a significantly increased population of CD4 + T-cells which expressed the surface protein CD40L in comparison to sham operated mice [n≥7; p<0.05; WT 10.8 ± 0.2% vs. sham 6.4 ± 0.5%]. CD40L is typically expressed in T-cells activated by T-cell receptor engagement. OT-II mice carry a transgenic T-cell receptor with specificity for an ovalbumin-derived peptide. These mice have a limited T-cell receptor repertoire, dominated by specificity for the irrelevant antigen ovalbumin. After 30 minutes of ischemia and 24 hours of reperfusion OT-II mice showed significantly reduction in infarct size [n≥4; p= 0.02; infarct/area at risk: OTII mice 38.9 ± 2.4% vs. WT mice 63.7 ± 6.6 % ]. Administration of a CD40L blocking antibody to wildtype mice also reduced infarct size when compared to administration of isotype-matched antibodies [n≥6; p = 0.03; infarct/ area at risk: anti-CD154 treatment 60.4 ± 3.4% vs. control 75.3 ± 4.1%]. CD4 + CD25 + Foxp3 + T-cells (natural T-regulatory cells) have a low activation threshold and constitute a T-cell subset with reactivity against autoantigens. Depletion of these cells by diphtheria-toxin application in a mouse model expressing the diphtheria-toxin receptor under the Foxp3 promotor also resulted in a significant reduction of infarct size when compared to diphtheria-toxin treated wildtype mice [n≥4; p=0.03; infarct/ area at risk: T reg -depleted DEREG mice 51.9± 3% vs. WT littermates 72.3± 2%]. Conclusion: Our results indicate that CD4 + T-cells that have been activated by an MHC class II/ T-cell receptor dependent mechanism, presumably by autoantigen recognition, contribute to myocardial ischemia-reperfusion injury.

P3391Cholesterol crystals in culprit coronary artery with acute myocardial infarction and their relation to myocardial salvage

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T Nunohiro ◽  
S Kuwasaki ◽  
T Fukushima ◽  
S Furudono ◽  
H Suenaga ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
At Risk ◽  
Coronary Artery ◽  
Infarct Size ◽  
Myocardial Salvage ◽  
Area At Risk ◽  
Risk Area ◽  
Contrast Enhanced ◽  
Delayed Enhancement Imaging

Abstract The involvement of cholesterol crystals (CCs) in plaque progression and destabilization of atherosclerotic plaques has been recently recognized. However, little is known about CCs and myocardial salvage in the Acute myocardial infarction (AMI) patients. This study aimed to evaluate the association between the existence of CCs at the site of culprit coronary artery and myocardial salvage index (MSI).To investigate, we applied the diagnostic resources of Optical Coherence Tomography (OCT). Methods This study included 53 AMI patients (90% with STEMI) who underwent primary PCI within 24h of onset. 53 STEMI patients underwent magnetic resonance imaging (CMR) of 5th days and 3 months after PCI. Infarct size was measured on delayed-enhancement imaging, and area at risk was quantified on T2-weighted imaging. MSI was calculated as [area at risk − infarct size] × 100/area at risk. 3 months CMR with contrast-enhanced imaging of late gadolinium enhancement-LGE. Patients were divided 2 groups according to the existence of CCs at the site of culprit coronary artery. Results CCs occurs in 26 of 53 (49%). Acute 5th days risk area (13.5±4.1 vs 12.6±4.9, P=0.48) and 3months infarct size (5.3±3.5 vs 7.0±3.2, P=0.066) were not significant between CCs and no CCs group. But salvage index were significantly lower in patients with CCs group (47.7±17.5% vs 60.1±20.2%, P=0.021) Conclusion Salvage index in patients that CCs were found by the OCT analysis, remain low after AMI. This study demonstrates the potential correlation between the myocardial salvage and vulnerable morphological features of culprit lesion to the presence of CCs with AMI patients.

Responses to coronary artery occlusion in conscious dogs with selective cardiac denervation

1988 ◽  
Vol 255 (3) ◽  
pp. H525-H533 ◽  
Author(s):  
Y. T. Shen ◽  
D. R. Knight ◽  
S. F. Vatner ◽  
W. C. Randall ◽  
J. X. Thomas
Keyword(s):  
At Risk ◽  
Blood Flow ◽  
Coronary Artery ◽  
Infarct Size ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Conscious Dogs ◽  
Wall Thickening ◽  
Area At Risk ◽  
Cardiac Denervation

The extent to which cardiac denervation alters responses to myocardial ischemia remains controversial. This study compared responses to 24-h coronary artery occlusion (CAO) on measurements of wall thickness (ultrasonic crystals), regional myocardial blood flow (microspheres), and infarct size (triphenyltetrazolium chloride technique) in three groups of conscious dogs with 1) selective posterior left ventricular (LV) wall denervation, 2) selective ventricular denervation, or in 3) intact dogs. After CAO, hemodynamic changes were not different among the three groups. Wall thickening in the ischemic zone became akinetic or paradoxical early after CAO and did not recover in any group over the 24-h monitoring period. Blood flow in the area at risk fell similarly in all groups. Infarct size, as a percentage of the area at risk, was 45 +/- 7% in intact, 48 +/- 6% in posterior LV wall-denervated, and 48 +/- 8% in ventricular-denervated group. There was, however, a lower (P less than 0.05) frequency of arrhythmic beats per minute after 3 h of CAO in the ventricular-denervated group (3.2 +/- 1.4) compared with the intact (11.3 +/- 4.1) or posterior wall-denervated (12.6 +/- 3.2) group. An additional group of ventricular-denervated dogs was studied to determine the effects of sequential, brief 2-min CAO at 2, 4, and 8 wk after denervation. Responses of regional wall thickening to CAO were not affected significantly even after 8 wk following ventricular denervation. Thus, in conscious dogs, neither selective ventricular denervation nor selective denervation of the posterior LV wall improved collateral blood flow, affected regional function favorably, or reduced infarct size after CAO.

Microembolization in pigs: effects on coronary blood flow and myocardial ischemic tolerance

1999 ◽  
Vol 277 (2) ◽  
pp. H533-H542 ◽  
Author(s):  
Frank Grund ◽  
Hilchen T. Sommerschild ◽  
Torstein Lyberg ◽  
Knut A. Kirkebøen ◽  
Arnfinn Ilebekk
Keyword(s):  
At Risk ◽  
Blood Flow ◽  
Infarct Size ◽  
Coronary Blood Flow ◽  
Tissue Perfusion ◽  
Ischemic Tolerance ◽  
Common Finding ◽  
Area At Risk ◽  
Maximal Increase ◽  
Time Flow

Coronary microembolization has been reported to increase coronary blood flow (CBF) through adenosine release. Because adenosine may increase ischemic tolerance against infarction, we tested the hypothesis that myocardial microembolization, a common finding in patients with ischemic heart disease, induces cardioprotection. Additionally, because the use of microspheres is a common tool to measure tissue perfusion, the effects of small amounts of microspheres on CBF were examined. Using anesthetized pigs, we measured CBF with a transit time flow probe on the left anterior descending coronary artery (LAD). In six pigs the relationship between the amount of injected microspheres (0–40 × 106, 15 μm in diameter, left atrial injections) and the effect on CBF was examined. Coronary hyperemia occurred, which was linearly related to the amount of microspheres injected: maximal increase in CBF (%) = 2.8 ± 1.5 (SE) + (5.8 ± 0.7 × 10−7× number of injected microspheres). Because injection of 40 × 106microspheres induced a long-lasting hyperemic response, which could be blocked by 8- p-sulfophenyl theophylline, ischemic tolerance was examined in five other pigs after two injections, each of 40 × 106microspheres, at a 30-min interval. Six control pigs had no injections. Ischemic tolerance was evaluated by measuring infarct size (tetrazolium stain) as the percentage of area at risk (fluorescent particles) after 45 min of LAD occlusion followed by 2 h of reperfusion. Pretreatment by microspheres increased infarct size from 60 ± 3% of area at risk in control animals to 84 ± 6% ( P< 0.05). The injection of microspheres induced a significant hyperemic flow response without causing necrosis by itself. We conclude that microembolization, evoking coronary hyperemia, does not improve but reduces myocardial ischemic tolerance against infarction in pigs.

Mechanisms of Isoflurane-induced Myocardial Preconditioning in Rabbits 

1999 ◽  
Vol 90 (3) ◽  
pp. 812-821 ◽  
Author(s):  
Mohamed S. Ismaeil ◽  
Igor Tkachenko ◽  
Kurt A. Gamperl ◽  
Robert F. Hickey ◽  
Brian A. Cason
Keyword(s):  
At Risk ◽  
Potassium Channels ◽  
Infarct Size ◽  
Adenosine Triphosphate ◽  
Ischemic Preconditioning ◽  
Adenosine Receptors ◽  
Coronary Occlusion ◽  
Myocardial Infarct ◽  
Myocardial Infarct Size ◽  
Area At Risk

Background Isoflurane has cardioprotective effects that mimic the ischemic preconditioning phenomenon. Because adenosine triphosphate-sensitive potassium channels and adenosine receptors are implicated in ischemic preconditioning, the authors wanted to determine whether the preconditioning effect of isoflurane is mediated through these pathways. Methods Myocardial infarct size was measured in seven groups of propofol-anesthetized rabbits, each subjected to 30 min of anterolateral coronary occlusion followed by 3 h of reperfusion. Groups differed only in the pretreatments given, and controls received no pretreatment. An ischemia-preconditioned group was pretreated with 5 min of coronary occlusion and 15 min of reperfusion. An isoflurane-preconditioned group was pretreated with 15 min end-tidal isoflurane, 1.1%, and then 15 min of washout. An isoflurane-plus-glyburide group was administered 0.33 mg/kg glyburide intravenously before isoflurane pretreatment. An isoflurane plus 8-(p-sulfophenyl)-theophylline (SPT) group received 7.5 mg/kg SPT intravenously before isoflurane. Additional groups were administered identical doses of glyburide or SPT, but they were not pretreated with isoflurane. Infarct size and area at risk were defined by staining. Data were analyzed by analysis of variance or covariance. Results Infarct size, expressed as a percentage of the area at risk (IS:AR) was 30.2+/-11% (SD) in controls. Ischemic preconditioning and isoflurane preexposure reduced myocardial infarct size significantly, to 8.3+/-5% and 13.4+/-8.2% (P&lt;0.05), respectively. Both glyburide and SPT pretreatment eliminated the preconditioning-like effect of isoflurane (IS:AR = 30.0+/-9.1% and 29.2+/-12.6%, respectively; P = not significant). Neither glyburide nor SPF alone increased infarct size (IS:AR = 33.9+/-7.6% and 31.8+/-12.7%, respectively; P = not significant). Conclusions Glyburide and SPT abolished the preconditioning-like effects of isoflurane but did not increase infarct size when administered in the absence of isoflurane. Isoflurane-induced preconditioning and ischemia-induced preconditioning share similar mechanisms, which include activation of adenosine triphosphate-sensitive potassium channels and adenosine receptors.

scholarly journals Subacute cardiac rubidium-82 positron emission tomography (82Rb-PET) to assess myocardial area at risk, final infarct size, and myocardial salvage after STEMI

2016 ◽  
Vol 25 (3) ◽  
pp. 970-981 ◽  
Author(s):  
Adam Ali Ghotbi ◽  
Andreas Kjaer ◽  
Lars Nepper-Christensen ◽  
Kiril Aleksov Ahtarovski ◽  
Jacob Thomsen Lønborg ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
At Risk ◽  
Infarct Size ◽  
Emission Tomography ◽  
Myocardial Salvage ◽  
Area At Risk ◽  
Myocardial Area ◽  
Positron Emission ◽  
Final Infarct Size ◽  
Rubidium 82

scholarly journals Reduction of myocardial infarction by postischemic administration of the calpain inhibitor A-705253 in comparison to the Na+/H+ exchange inhibitor Cariporide® in isolated perfused rabbit hearts

2008 ◽  
Vol 389 (12) ◽  
Author(s):  
Christiane Neuhof ◽  
Verena Fabiunke ◽  
Maria Speth ◽  
Achim Möller ◽  
Hans Fritz ◽  
...  
Keyword(s):  
At Risk ◽  
Infarct Size ◽  
Left Ventricular ◽  
Staining Procedure ◽  
Calpain Inhibitor ◽  
Perfusion Fluid ◽  
Area At Risk ◽  
Infarcted Area ◽  
Exchange Inhibitor ◽  
Significant Difference

Abstract The calpain inhibitor A-705253 and the Na+/H+-exchange inhibitor Cariporide® were studied in isolated perfused rabbit hearts subjected to 60 min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid solely or in combination at the beginning of reperfusion. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were performed. Myocardial infarct size and area at risk (transiently not perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 72.7±4.0% of the area at risk in untreated controls, but was significantly smaller in the presence of the inhibitors. The largest effect was observed with 10-6 M A-705253, which reduced the infarcted area to 49.2±4.1% of the area at risk, corresponding to a reduction of 33.6%. Cariporide® at 10-6 M reduced the infarct size to the same extent. The combination of both inhibitors, however, did not further improve cardioprotection. No significant difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, heart rate, or in the release of lactate dehydrogenase and creatine kinase from heart muscle.

Remifentanil Preconditioning Confers Cardioprotection via  Cardiac κ- and δ-Opioid Receptors

2005 ◽  
Vol 102 (2) ◽  
pp. 371-378 ◽  
Author(s):  
Ye Zhang ◽  
Michael G. Irwin ◽  
Tak Ming Wong ◽  
Mai Chen ◽  
Chun-Mei Cao
Keyword(s):  
At Risk ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Infarct Size ◽  
Ischemic Preconditioning ◽  
Katp Channel ◽  
Area At Risk ◽  
Mitochondrial Katp Channel ◽  
Ringer’S Solution ◽  
Kinase C

Background Remifentanil preconditioning (RPC) reduces the infarct size in anesthetized rat hearts, and this effect seems to be mediated by all three types of opioid receptors (ORs). Because there is evidence of only kappa- and delta- but not mu-ORs in the rat heart, the authors investigated whether RPC confers cardioprotection via cardiac kappa- and delta-OR as well as via extracardiac mu-OR agonist activity. The authors also investigated the involvement of signaling mechanisms, namely protein kinase C and mitochondrial adenosine triphosphate-sensitive potassium (KATP) channels. Methods The hearts of male Sprague-Dawley rats weighing 190-210 g were removed, mounted on a Langendorff apparatus, and perfused retrogradely at 100 cm H2O with Krebs-Ringer's solution. All hearts were subjected to 30 min of ischemia and 2 h of reperfusion. The study consisted of three series of experiments on the effect of ischemic preconditioning or RPC (10, 50, and 100 ng/ml remifentanil) after blockade of OR subtypes (delta-OR antagonist naltrindol, kappa-OR antagonist nor-binaltorphimine, and mu-OR antagonist CTOP). The involvement of protein kinase C or the KATP channel in the cardioprotection of RPC was also investigated using specific blockers in each group. RPC was produced by three cycles of 5-min perfusion of remifentanil in Krebs-Ringer's solution interspersed with a 5-min reperfusion with Krebs solution only. Infarct size, as a percentage of the area at risk, was determined by 2,3,5-triphenyltetrazolium staining. Results Infarct size as a percentage of the area at risk was significantly reduced after RPC from 51.9 +/- 5.0% (control, n = 8) to 36.2 +/- 10.0% (100 ng/ml RPC, n = 8, P &lt; 0.01). This effect was stopped by pretreatment with naltrindol (52.3 +/- 5.2%) and nor-binaltorphimine (43.5 +/- 6.0%) but not CTOP (37.1 +/- 6.0%). Chelerythrine and GF109203X, both protein kinase C inhibitors, abolished the effects of RPC or ischemic preconditioning on infarct size as a percentage of area at risk. 5-Hydroxydecanoate (a selective mitochondrial KATP channel blocker) also abolished the cardioprotection of RPC and IPC, but HMR-1098 (a selective inhibitor of the sarcolemmal KATP channel) did not. Conclusion Cardiac delta- and kappa- but not mu-ORs mediate the cardioprotection produced by RPC. Both protein kinase C and the mitochondrial KATP channel were involved in this effect.

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