Abstract 13498: Reperfusion Therapy With Rapamycin Prevents Myocardial Ischemic Injury, Through Activation of AKT and ERK

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Scott M Filippone ◽  
Sean K Roh ◽  
Fadi N Salloum ◽  
Rakesh C Kukreja ◽  
Anindita Das
Keyword(s):  
Infarct Size ◽  
Map Kinases ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Reperfusion Therapy ◽  
Tunel Staining ◽  
Coronary Artery Ligation ◽  
Myocardial Infarct Size ◽  
Artery Ligation ◽  
Tetrazolium Chloride

Background: The selective inhibitor of mammalian target of rapamycin (mTOR), rapamycin (RAPA), has been shown to exert preconditioning-like cardioprotective effects against ischemia/reperfusion (I/R) injury. Two distinct mTOR complexes (mTORC1 and mTORC2) differentially regulate cardiomyocyte apoptosis and tissue damage following myocardial infarction. We hypothesized that reperfusion therapy with RAPA would reduce myocardial infarct size through differential modulation of mTOR complexes and MAP kinases. Methods and Results: Adult C57BL mice were subjected to 30 min of ischemia via left anterior descending coronary artery ligation followed by reperfusion for 24 hr. RAPA (0.25 mg/kg) or 10% DMSO (volume-matched control) was administered via intra-cardiac injection at the onset of reperfusion. Post I/R survival (90%) and cardiac function (fractional shortening, FS: 26.9±2.6%) were improved in RAPA-treated mice compared to control (survival: 60%, FS:16.7±3.2%). Additionally, RAPA caused significant reduction in myocardial infarct size (Fig. 1A), measured by tetrazolium chloride staining, and apoptosis (Fig. 1B) in peri-infarct regions, assessed by TUNEL staining. Western blot analysis revealed that RAPA restored Akt473 phosphorylation (target of mTORC2), but reduced ribosomal protein S6 phosphorylation (target of mTORC1) following I/R injury (Fig. 1C). The protective effect of RAPA was associated with increased phosphorylation of ERK1/2 and decreased phosphorylation of P38 (Fig. 1D). RAPA also attenuated pro-apoptotic protein Bax, in concert with increased pro-survival Bcl2 to Bax ratio (Fig. 1E). Conclusion: Reperfusion therapy with RAPA protects hearts against I/R injury by selective activation of mTORC2 and ERK with concurrent inhibition of mTOC1 and P38. We propose that RAPA could be a novel treatment strategy to modulate mTOR complexes and MAP kinase signaling for attenuation of reperfusion injury in the heart.

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 14045: Reperfusion Therapy With Recombinant Human Relaxin (Serelaxin) Attenuates Myocardial Inflammasome Formation and Ischemic Injury in Mice via eNOS-dependent Mechanism

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Juan Valle Raleigh ◽  
Adolfo G Mauro ◽  
Carlo Marchetti ◽  
Jun He ◽  
Stefano Toldo ◽  
...  
Keyword(s):  
Infarct Size ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion ◽  
Ischemic Injury ◽  
Reperfusion Therapy ◽  
Coronary Artery Ligation ◽  
Myocardial Infarct Size ◽  
Caspase 1 ◽  
Anti Inflammatory ◽  
Dependent Mechanism

Background: The preconditioning-like infarct-sparing and anti-inflammatory effects of the peptide hormone relaxin following ischemic injury have been studied in the heart. Whether reperfusion therapy with recombinant human relaxin (serelaxin, SRLX) reduces myocardial infarct size and attenuates NLRP3 inflammasome formation/caspase-1 activation and subsequent loss of functional myocardium following ischemia/reperfusion (I/R) injury is unknown. Methods and Results: After baseline echocardiography, adult male C57BL (WT) or eNOS knockout (KO) mice underwent myocardial infarction (MI) by coronary artery ligation for 30 minutes followed by 24 h reperfusion. Mice were treated with either SRLX (10 μg/Kg; sc) or saline 5 minutes before reperfusion. SRLX improved survival at 24 h post MI in WT mice (79%) as compared with controls (42%), whereas there was no difference in survival between SRLX- and saline-treated eNOS KO mice. Moreover, SRLX significantly reduced infarct size, measured with TTC staining, and preserved LV fractional shortening (FS) and end-systolic diameter (LVESD) in WT mice as compared with controls. Interestingly, cardiac caspase-1 activity was markedly reduced in SRLX-treated mice compared with controls at 24 h post MI (Figure A-D). Genetic deletion of eNOS abolished the infarct-sparing and anti-inflammatory effects of SRLX as well as functional preservation. SRLX plasma levels were assessed 5 min. after treatment using ELISA and the results demonstrate therapeutic levels comparable to plasma relaxin during the first trimester of pregnancy (Figure E). Conclusion: Reperfusion therapy with SRLX attenuates myocardial I/R injury and NLRP3 inflammasome formation via eNOS-dependent mechanism. We propose that SRLX possesses an anti-inflammatory effect preventing caspase-1 activation and inflammatory complications following MI, which may shed some light on the mechanism behind the survival benefit observed in the RELAX-AHF trial.

scholarly journals Reperfusion Therapy with Rapamycin Attenuates Myocardial Infarction through Activation of AKT and ERK

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Scott M. Filippone ◽  
Arun Samidurai ◽  
Sean K. Roh ◽  
Chad K. Cain ◽  
Jun He ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Infarct Size ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Mammalian Target Of Rapamycin ◽  
Reperfusion Therapy ◽  
Myocardial Infarct Size ◽  
Ribosomal Protein S6 ◽  
Cardioprotective Effects ◽  
Fractional Shortening

Prompt coronary reperfusion is the gold standard for minimizing injury following acute myocardial infarction. Rapamycin, mammalian target of Rapamycin (mTOR) inhibitor, exerts preconditioning-like cardioprotective effects against ischemia/reperfusion (I/R) injury. We hypothesized that Rapamycin, given at the onset of reperfusion, reduces myocardial infarct size through modulation of mTOR complexes. Adult C57 male mice were subjected to 30 min of myocardial ischemia followed by reperfusion for 1 hour/24 hours. Rapamycin (0.25 mg/kg) or DMSO (7.5%) was injected intracardially at the onset of reperfusion. Post-I/R survival (87%) and cardiac function (fractional shortening, FS:28.63±3.01%) were improved in Rapamycin-treated mice compared to DMSO (survival: 63%, FS:17.4±2.6%). Rapamycin caused significant reduction in myocardial infarct size (IS:26.2±2.2%) and apoptosis (2.87±0.64%) as compared to DMSO-treated mice (IS:47.0±2.3%; apoptosis:7.39±0.81%). Rapamycin induced phosphorylation of AKT S473 (target of mTORC2) but abolished ribosomal protein S6 phosphorylation (target of mTORC1) after I/R. Rapamycin induced phosphorylation of ERK1/2 but inhibited p38 phosphorylation. Infarct-limiting effect of Rapamycin was abolished with ERK inhibitor, PD98059. Rapamycin also attenuated Bax and increased Bcl-2/Bax ratio. These results suggest that reperfusion therapy with Rapamycin protects the heart against I/R injury by selective activation of mTORC2 and ERK with concurrent inhibition of mTORC1 and p38.

Abstract 289: Cardiac-Specific Ectonucleoside Triphosphate Diphosphohydrolase 1 Overexpression Affords Protection from Myocardial Infarction and Reperfusion Injury

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Zhaobin Xu ◽  
Debra G Wheeler ◽  
Shouvik D Mahamud ◽  
Karen M Dwyer ◽  
Simon C Robson ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Myocardial Infarct Size ◽  
Area At Risk ◽  
Tetrazolium Chloride ◽  
Myocardial Ischemia Reperfusion

Background: During myocardial stress, extracellular levels of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) increase. These extracellular ATP and ADP levels are modulated via hydrolysis by ectonucleoside triphosphate diphosphohydrolase 1 (ENTDP-1/CD39) to adenosine monophosphate (AMP) subsequently converted by ecto-5'-nucleotidase (CD73) to the anti-thrombotic, cardioprotective nucleoside, adenosine. Previous data demonstrated significantly smaller infarcts in mice globally overexpressing CD39. The current objective was to determine whether tissue specific overexpression of CD39 in the heart would reduce myocardial ischemia/reperfusion injury. Methods: Myocardial ischemia/reperfusion (I/R) injury was evaluated in transgenic mice overexpressing human CD39 driven by the α-MHC promoter. I/R injury was induced by ligation of the left anterior descending (LAD) artery for 60 min followed by 24 hours of reperfusion. Myocardial infarct size was determined by staining with triphenyl tetrazolium chloride (TTC) and the area-at-risk was delineated by perfusion with 5% Phthalo Blue. Results: Expression of CD39 in the heart tissue was confirmed by Western blot analysis. In response to 60 minutes of ischemia followed by 24 hours of reperfusion, α-MHC CD39-OE animals displayed a marked reduction in infarct size (WT: 31.68%±4.64 vs TG: 6.14%± 2.48, N=5/group, P<0.01), relative to wild-type controls (Figure). Conclusions: Overexpression of CD39 in cardiac tissue alone significantly attenuates myocardial ischemic injury.

Abstract 300: Topical Application of IcyHot Reduces Myocardial Infarct Size in Rodents by a TRPA1-dependent Mechanism

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Yun Wu ◽  
Yao Lu ◽  
Eric R Gross
Keyword(s):  
Infarct Size ◽  
Transient Receptor Potential ◽  
Ischemia Reperfusion Injury ◽  
Calcium Influx ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Myocardial Infarct Size ◽  
Sprague Dawley ◽  
Area At Risk ◽  
Reactive Aldehydes

Toxic reactive aldehydes are formed during ischemia-reperfusion. The ion channel transient receptor potential ankryin 1 (TRPA1) is irreversibly modified by reactive aldehydes which can cause calcium influx and cell death. Here we tested whether topically applied creams containing a reversible TRPA1 agonist could reduce myocardial infarct size. Male Sprague-Dawley rats 8-10 weeks age were subjected to an in vivo myocardial ischemia-reperfusion model of 30 minutes of left anterior descending (LAD) coronary artery ischemia followed by 2 hours reperfusion. Prior to ischemia, rats were untreated or had 1g of cream applied to the abdomen. The creams tested were IcyHot, Bengay, Tiger Balm, or preparation H (Fig. 1A). Hearts were negatively stained for the area at risk and the infarct size was determined by using TTC staining (Fig. 1B). A subset of rodents prior to receiving IcyHot also received an intravenous bolus of the TRPA1 antagonist TCS-5861528 (1mg/kg) or AP-18 (1mg/kg). Interestingly, both IcyHot and Bengay reduced myocardial infarct size compared to untreated rodents (Fig. 1C and 1D IcyHot: 41±3%*, Bengay: 50±2%* versus control 62±1%, n=6/group, *P<0.001). Both preparation H and Tiger Balm failed to reduce myocardial infarct size (Tiger Balm: 63±2%, preparation H 59±2%). Giving a TRPA1 antagonist prior to IcyHot also blocked the reduction in infarct size. Our additional data also indicates the methyl salicylate (mint) in IcyHot and Bengay is the agent that limits myocardial infarct size. Since IcyHot and Bengay are safely used by humans, targeting TRPA1 by using products such as these could be quickly translatable and widely used to reduce ischemia-reperfusion injury.

scholarly journals The Antioxidant, Anti-Inflammatory and Anti-Apoptotic Activities of the Bauhinia Championii Flavone are Connected with Protection Against Myocardial Ischemia/Reperfusion Injury

2016 ◽  
Vol 38 (4) ◽  
pp. 1365-1375 ◽  
Author(s):  
Jie Jian ◽  
Feifei Xuan ◽  
Feizhang Qin ◽  
Renbin Huang
Keyword(s):  
Myocardial Ischemia ◽  
Caspase 3 ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Tunel Staining ◽  
Myocardial Infarct Size ◽  
Myocardial Ischemia Reperfusion

Background/Aims: Previous studies have demonstrated that Bauhinia championii flavone (BCF) exhibits anti-oxidative, anti-hypoxic and anti-stress properties. This study was designed to investigate whether BCF has a cardioprotective effect against myocardial ischemia/reperfusion (I/R) injuries in rats and to shed light on its possible mechanism. Methods: The model of I/R was established by ligating the left anterior descending coronary artery for 30 min, then reperfusing for 180 min. Hemodynamic changes were continuously monitored. The content of malondialdehyde (MDA) as well as the lactate dehydrogenase (LDH), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were assessed. The release of interleukin-6 (IL-6) was measured by enzyme-linked immunosorbent assay (ELISA). Apoptosis of cardiomyocytes was determined by caspase-3 activity and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The expression of TLR4, NF-κBp65, Bcl-2 and Bax were detected by western blotting. Results: Pretreatment with BCF significantly reduced the serum levels of LDH, MDA and IL-6, but increased the activities of SOD and GSH-Px. It also attenuated myocardial infarct size, reduced the apoptosis rate and preserved cardiac function. Furthermore, BCF inhibited caspase-3 activity and the expression of TLR4, phosphorylated NF-κBp65 and Bax, but enhanced the expression of Bcl-2. Conclusion: These results provide substantial evidence that BCF exerts a protective effect on myocardial I/R injury, which may be attributed to attenuating lipid peroxidation, the inflammatory response and apoptosis.

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