Abstract 165: Diacylglycerol kinase α Exacerbates Cardiac Injury After Ischemia/reperfusion In Transgenic Mouse Hearts

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Toshiki Sasaki ◽  
Yasuchika Takeishi ◽  
Tatsuro Kitahara ◽  
Yo Koyama ◽  
Takeshi Niizeki ◽  
...  
Keyword(s):  
At Risk ◽  
Infarct Size ◽  
Systolic Function ◽  
Ischemia Reperfusion ◽  
Cardiac Injury ◽  
Fold Increase ◽  
Left Ventricular Systolic Function ◽  
Left Ventricular ◽  
Area At Risk ◽  
Wild Type Littermate

Background: Activation of the diacylglycerol-protein kinase C (DAG-PKC) cascade has been implicated in cardiac dysfunction after ischemia/reperfusion (I/R). DAG kinase (DGK) terminates DAG signaling by converting it to phosphatidic acid, and thus may act as a regulator of DAG-PKC signaling. It has been reported that α, ϵ, and &#03B6; isoforms of DGK have been identified in the heart. We examined the functional role of DGKα in cardiac injury after I/R. Methods and Results: We generated transgenic mice with cardiac specific overexpression of DGKα (DGKα-TG) using α-myosin heavy chain promoter. Left anterior descending coronary artery was transiently occluded for 30 min and reperfused for 24 hr in DGKα-TG and wild type littermate (WT) mice. After 24 hr, echocardiography was performed, mice were sacrificed, and the hearts were removed. Areas at risk and infarct size were assessed by Evans blue/TTC double staining. Left ventricular chamber dilatation after I/R was more pronounced in DGKα-TG mice than in WT mice (left ventricular end-diastolic dimension: 3.44 +/− 0.41 mm vs. 3.05 +/−0.24 mm, P < 0.01). Left ventricular systolic function was more severely depressed in DGKα-TG mice than in WT mice (left ventricular fractional shortening: 34.3 +/− 3.6% vs. 42.2 +/− 4.0%, P < 0.01). The ratio of infarct size/area at risk at 24 hr after I/R was larger in DGKα-TG mice than in WT mice (17.9 +/− 4.2% vs. 11.3 +/− 3.3%, P < 0.01). The phosphorylation activity of extracellular-signal regulated kinase (ERK) was increased after I/R in WT mouse hearts (2.58 +/−0.52-fold increase, P<0.0001). However in DGKα-TG mice, activation of ERK after I/R was abolished (1.77+/−0.67-fold increase, P<0.01 vs. WT). Conclusion: DGKα exacerbates cardiac injury by inhibiting cardio-protective effect of ERK activation.

scholarly journals Inhibition of Type 2 Sodium-Glucose Transporters and Na+/H+ Exchanger-1 produces similar cardioprotective effects in response to ischemiareperfusion injury

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Bianca S. Blaettner ◽  
Hana E. Baker ◽  
Adam G. Goodwill ◽  
Hannah E. Clark ◽  
Michael C. Kozlowski ◽  
...  
Keyword(s):  
At Risk ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Glucose Transporters ◽  
Left Ventricular ◽  
Area At Risk ◽  
Cardioprotective Effects

Background and Hypothesis: Recent studies indicate that inhibition of Type 2 Sodium-Glucose Transporters (SGLT2i) augments diastolic filling volume and mitigates myocardial ischemic injury. This study tested the hypothesis that inhibition of the Na+/H+ Exchanger-1 (NHE-1) mimics the cardioprotective effects of SGLT2i in response to ischemia-reperfusion injury. Experimental Design or Project Methods: Lean swine (~50 kg) were anesthetized, a thoracotomy performed, and perivascular flow transducers placed around the left anterior descending (LAD) and circumflex coronary (LCX) arteries. A pressure-volume (PV) catheter was then inserted into the left ventricle. Swine received a 15 min infusion of vehicle (DMSO; n = 3), the SGLT2i Canagliflozin (30 µM; n = 3), or the NHE-1 inhibitor Cariporide (1µM; n = 3) prior to a 60 min total occlusion of the LCX and 2-hour reperfusion period. Following reperfusion, the LCX was re-occluded and a 2.5% Patent Blue 5 solution was administered to identify area at risk. The heart was excised, sectioned, and incubated in a 2,3,5-triphenyltetrazolium chloride (TTC) solution. Images were collected and analyzed for area at risk and infarct size. Results: In the vehicle treated group, 2 of the 3 swine studied died prematurely before the completion of the protocol; one at baseline and one during ischemia. Our initial findings support that left ventricular end diastolic volume increases in response to regional myocardial ischemia in swine that received either Canagliflozin or Cariporide. This increase in diastolic volume was associated with an increase in stroke volume (i.e. Frank-Starling effect) and a reduction in myocardial infarct size in both treatment groups. Blood pressure tended to decrease to a similar extent in all groups. Conclusion and Potential Impact: These pilot studies suggest that inhibition of SGLT2 and NHE-1 produces similar functional and protective effects in response to regional ischemia-reperfusion injury. Further experiments are needed to corroborate these findings and examine the extent to which SGLT2i directly modulates NHE-1 activity.

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.

scholarly journals Nrf2 Deficiency Unmasks the Significance of Nitric Oxide Synthase Activity for Cardioprotection

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Ralf Erkens ◽  
Tatsiana Suvorava ◽  
Thomas R. Sutton ◽  
Bernadette O. Fernandez ◽  
Monika Mikus-Lelinska ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
De Novo ◽  
Ischemia Reperfusion Injury ◽  
Systolic Function ◽  
Ischemia Reperfusion ◽  
Systolic Dysfunction ◽  
Left Ventricular ◽  
Early Reperfusion ◽  
Myocardial Ischemia Reperfusion

The transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a key master switch that controls the expression of antioxidant and cytoprotective enzymes, including enzymes catalyzing glutathione de novo synthesis. In this study, we aimed to analyze whether Nrf2 deficiency influences antioxidative capacity, redox state, NO metabolites, and outcome of myocardial ischemia reperfusion (I/R) injury. In Nrf2 knockout (Nrf2 KO) mice, we found elevated eNOS expression and preserved NO metabolite concentrations in the aorta and heart as compared to wild types (WT). Unexpectedly, Nrf2 KO mice have a smaller infarct size following myocardial ischemia/reperfusion injury than WT mice and show fully preserved left ventricular systolic function. Inhibition of NO synthesis at onset of ischemia and during early reperfusion increased myocardial damage and systolic dysfunction in Nrf2 KO mice, but not in WT mice. Consistent with this, infarct size and diastolic function were unaffected in eNOS knockout (eNOS KO) mice after ischemia/reperfusion. Taken together, these data suggest that eNOS upregulation under conditions of decreased antioxidant capacity might play an important role in cardioprotection against I/R. Due to the redundancy in cytoprotective mechanisms, this fundamental antioxidant property of eNOS is not evident upon acute NOS inhibition in WT mice or in eNOS KO mice until Nrf2-related signaling is abrogated.

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.

Effects of Endotoxin on Neutrophil-Mediated Ischemia/Reperfusion Injury in the Rat Heart In Vivo

2001 ◽  
Vol 226 (4) ◽  
pp. 320-327 ◽  
Author(s):  
Brian P. Lipton ◽  
Joseph B. Delcarpio ◽  
Kathleen H. McDonough
Keyword(s):  
At Risk ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Isolated Heart ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Necrotic Area ◽  
Area At Risk

We have previously shown that a nonlethal dose of lipopolysaccharide (LPS) decreases L-selectin expression of neutrophils (PMNs), thereby preventing PMN-mediated reperfusion injury in the isolated heart. In the present study we determined whether or not that dose of LPS would protect hearts during in vivo ischemia and reperfusion by preventing PMN-induced reperfusion injury. Rats receiving saline vehicle showed marked myocardial injury (necrotic area/area at risk = 82% ± 2%) and significant depression in left ventricular function as assessed in the isolated isovolumic heart preparation at constant flow rates of 5, 10, 15, and 20 ml/min. The administration of LPS (100 μg/kg body wt) 7 hr prior to ischemia resulted in a reduction in myocardial damage (necrotic area/area at risk = 42% ± 3%) and preservation of function. Myocardial function was similar to that of sham ischemic saline- and LPS-treated rats. Moreover, PMN infiltration as determined by histology was quantitatively more severe in hearts of saline-treated rats than in hearts of LPS-treated rats. Isolated hearts from vehicle- and LPS-treated animals undergoing sham ischemia in vivo recovered to the same extent after in vitro ischemia/reperfusion, suggesting that LPS did not induce protection by altering intrinsic properties of the heart. Our results indicate that LPS-induced protection of the heart from in vivo PMN-mediated ischemia/reperfusion injury may be due to decreased L-selectin expression of PMNs in LPS-treated animals.

Signalling pathways in ischaemic postconditioning

2009 ◽  
Vol 101 (04) ◽  
pp. 626-634 ◽  
Author(s):  
Derek Hausenloy
Keyword(s):  
Cell Death ◽  
Infarct Size ◽  
Systolic Function ◽  
Myocardial Infarct ◽  
Left Ventricular Systolic Function ◽  
Left Ventricular ◽  
Myocardial Reperfusion ◽  
Signalling Pathways ◽  
Myocardial Infarct Size ◽  
Ventricular Systolic Function

SummaryCoronary heart disease (CHD) is the leading cause of death globally. Following an acute coronary artery occlusion, timely myocardial reperfusion using either primary percutaneous coronary intervention (PCI) or thrombolytic therapy remains the most effective treatment strategy for reducing myocardial infarct size, preventing left ventricular remodelling, preserving left ventricular systolic function and improving clinical outcomes. However, the full benefits of myocardial reperfusion are not realised, given that the actual process of reperfusing ischaemic myocardium can independently induce cell death – a phenomenon termed lethal reperfusion injury. Ischaemic postconditioning represents an innovative treatment strategy for limiting lethal myocardial reperfusion injury and further reducing myocardial infarct size for those patients undergoing primary PCI. It is achieved by interrupting the normal myocardial reperfusion process, with several intermittent episodes of coronary myocardial ischaemia induced by low-pressure inflations of the angioplasty balloon in the infarct-related coronary artery. Experimental studies demonstrate that this stuttered form of myocardial reperfusion improves myocardial perfusion, maintains endothelial function, attenuates apoptotic cell death, reduces myocardial infarct size, preserves left ventricular systolic function and reduces mortality. The mechanisms underlying the cardioprotective effect of ischaemic postconditioning are the subject of intense investigation. In this article we review the signalling pathways which have been implicated as potential mediators of ischaemic postconditioning, the identification of which have provided novel pharmacological targets of cardioprotection capable of recapitulating the protective benefits of ischaemic postconditioning.

Differential effects of postconditioning on myocardial stunning and infarction: a study in conscious dogs and anesthetized rabbits

2006 ◽  
Vol 291 (3) ◽  
pp. H1345-H1350 ◽  
Author(s):  
Nicolas Couvreur ◽  
Laurence Lucats ◽  
Renaud Tissier ◽  
Alain Bize ◽  
Alain Berdeaux ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Infarct Size ◽  
Myocardial Stunning ◽  
Ischemia Reperfusion ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Segment Length ◽  
Wall Thickening ◽  
Area At Risk

Postconditioning, i.e., brief intermittent episodes of myocardial ischemia-reperfusion performed at the onset of reperfusion, reduces infarct size after prolonged ischemia. Our goal was to determine whether postconditioning is protective against myocardial stunning. Accordingly, conscious chronically instrumented dogs (sonomicrometry, coronary balloon occluder) were subjected to a control sequence (10 min coronary artery occlusion, CAO, followed by coronary artery reperfusion, CAR) and a week apart to postconditioning with four cycles of brief CAR and CAO performed at completion of the 10 min CAO. Three postconditioning protocols were investigated, i.e., 15 s CAR/15 s CAO ( n = 5), 30 s CAR/30 s CAO ( n = 7), and 1 min CAR/1 min CAO ( n = 6). Left ventricular wall thickening was abolished during CAO and similarly reduced during subsequent stunning in control and postconditioning sequences (e.g., at 1 h CAR, 33 ± 4 vs. 34 ± 4%, 30 ± 4 vs. 30 ± 4%, and 33 ± 4 vs. 32 ± 4% for 15 s postconditioning, 30 s postconditioning, and 1 min postconditioning vs. corresponding control, respectively). We confirmed this result in anesthetized rabbits by demonstrating that shortening of left ventricular segment length was similarly depressed after 10 min CAO in control and postconditioning sequences (4 cycles of 30 s CAR/30 s CAO). In additional rabbits, the same postconditioning protocol significantly reduced infarct size after 30 min CAO and 3 h CAR (39 ± 7%, n = 6 vs. 56 ± 4%, n = 7 of the area at risk in postconditioning vs. control, respectively). Thus, contrasting to its beneficial effects on myocardial infarction, postconditioning does not protect against myocardial stunning in dogs and rabbits. Conversely, additional episodes of ischemia-reperfusion with postconditioning do not worsen myocardial stunning.

scholarly journals Neutrophil Extracellular Trap Components Associate with Infarct Size, Ventricular Function, and Clinical Outcome in STEMI

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Ragnhild Helseth ◽  
Christian Shetelig ◽  
Geir Øystein Andersen ◽  
Miriam Sjåstad Langseth ◽  
Shanmuganathan Limalanathan ◽  
...  
Keyword(s):  
At Risk ◽  
Clinical Outcome ◽  
Infarct Size ◽  
Left Ventricular ◽  
Clinical Event ◽  
Left Ventricular Ejection ◽  
Myocardial Salvage ◽  
Area At Risk ◽  
Ventricular Ejection Fraction ◽  
Clinical Events

Background. The relevance of neutrophil extracellular traps (NETs) in acute ST-elevation myocardial infarction (STEMI) is unclear. We explored the temporal profile of circulating NET markers and their associations to myocardial injury and function and to adverse clinical events in STEMI patients. Methods and Results. In 259 patients, blood samples were drawn before and after PCI, on day 1, and after 4 months. Double-stranded deoxyribonucleic acid (dsDNA) and myeloperoxidase-DNA (MPO-DNA) were measured in serum by a nucleic acid stain and ELISA. Cardiac magnetic resonance imaging assessed microvascular obstruction (MVO), area at risk, infarct size, myocardial salvage index, left ventricular ejection fraction (LVEF), and change in indexed left ventricular end-diastolic volume (LVEDVi). Clinical events were registered after 12 months. dsDNA and MPO-DNA levels were highest before PCI, with reduced levels thereafter (all p≤0.02). Patients with high vs. low day 1 dsDNA levels (>median; 366 ng/ml) more frequently had MVO, larger area at risk, larger infarct size acutely and after 4 months, and lower myocardial salvage index (all p<0.03). Moreover, they had lower LVEF acutely and after 4 months, and larger change in LVEDVi (all p≤0.014). High day 1 dsDNA levels also associated with risk of having a large infarct size (>75th percentile) and low LVEF (≤49%) after 4 months when adjusted for gender, time from symptoms to PCI, and infarct localization (OR 2.3 and 3.0, both p<0.021), and patients with high day 1 dsDNA levels were more likely to experience an adverse clinical event, also when adjusting for peak troponin T (hazard ratio 5.1, p=0.012). No such observations were encountered for MPO-DNA. Conclusions. High day 1 dsDNA levels after STEMI were associated with myocardial infarct size, adverse left ventricular remodeling, and clinical outcome. Although the origin of dsDNA could be discussed, these observations indicate a potential role for dsDNA in acute myocardial ischemia. This trial is registered with S-08421d, 2008/10614 (Regional Committee for Medical Research Ethics in South-East Norway (2008)).

Abstract 843: Cardiomyocyte Overexpression of the Hydrogen Sulfide Producing Enzyme Cystathioine gamma-Lyase Attenuates Myocardial Ischemia-Reperfusion Injury

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
John W Elrod ◽  
John W Calvert ◽  
Chi-Wing Chow ◽  
Joanna Morrison ◽  
Jeannette E Doeller ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Fold Increase ◽  
Area At Risk ◽  
Physiological Processes ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Background : Hydrogen sulfide (H 2 S) was recently discovered to be an endogenously produced gaseous second messenger capable of modulating many physiological processes. We have previously demonstrated that administration of a H 2 S donor limits the extent of myocardial infarction. This prompted us to investigate the potential of endogenously generated H 2 S in acute cardioprotection utilizing mice with transgenic overexpression of an H 2 S producing enzyme. Methods: Mice with cardiac-specific overexpression of murine cystathionine γ-lyase (αMHC-CGL-Tg) were generated and analyzed for increased enzyme expression and H 2 S production utilizing a H 2 S specific polarographic electrode. αMHC-CGL-Tg and WT mice were then subjected to 45 min of in vivo LCA ischemia and 72 hr reperfusion and infarct size was evaluated using TTC staining. Results: αMHC-CGL-Tg mice displayed an increased level of myocardial CGL RNA, which translated into a (15 fold) increase in protein expression. This increase in CGL enzyme resulted in a significant (2 fold) increase in H 2 S production by myocardial homogenates of αMHC-CGL-Tg mice. αMHC-CGL-Tg mice were found to have a 47% reduction in infarct size per area-at-risk (INF/AAR) as compared to WT littermates. AAR was similar between both groups. Conclusions: This is the first evidence that overexpression of a H 2 S producing enzyme can decrease infarct size following MI-R injury. These findings demonstrate that modulation of endogenous H 2 S production may be of clinical benefit in ischemic disorders and that H 2 S generating enzymes may be viable therapeutic targets.

Sign in / Sign up

Export Citation Format

Share Document