Reperfusion injury: fact or myth?

The Effect of Resveratrol on Sphingosine-1 and Oxidative/ Nitrosative Stress in an Experimental Heart Ischemia Reperfusion Model

Objectives: Resveratrol (RSV) is a natural polyphenolic compound showing significant antioxidant effects. In this study, we aimed to investigate the effects of resveratrol on the sphingosine-1-phosphate (S1P) and oxidative stress biomarkers in hearth ischemia-reperfusion (I/R).

Materials and Methods: The biochemical and histopathological effects of RSV on cardiac ischemia-reperfusion injury were investigated through ELISA- and light microscope.

Results: We observed statistically significant differences between the treatment group and the control group in terms of malondialdehyde (MDA) level, catalase (CAT) and superoxide dismutase (SOD) activities (p<0.05). Histopathologically, we also observed decreased Polymorphonuclear Leucocyte (PMNL) infiltration, myocardial edema, miyositolysis in the treatment group compared to the I/R and sham groups.

Conclusion: Resveratrol may play an important role in cardiac I/R injury through its anti-inflammatory and antioxidant effects which were biochemically and histopathologically confirmed in the present study.

Korean Red Ginseng enhances cardiac hemodynamics on doxorubicin-induced toxicity in rats

Background

Korean Red Ginseng (KRG) has been known to possess many ginsenosides. These ginsenosides are used for curing cardiovascular problems. The present study show the protective potential of KRG against doxorubicin (DOX)–induced myocardial dysfunction, by assessing electrocardiographic, hemodynamic, and biochemical parameters and histopathological findings.

Methods

Animals were fed a standard chow and adjusted to their environment for 3 days before the experiments. Next, the rats were equally divided into five groups (n = 9, each group). The animals were administered with KRG (250 and 500 mg/kg) for 10 days and injected with DOX (20 mg/kg, subcutaneously, twice at a 24-h interval) on the 8th and 9th day. Electrocardiography and echocardiography were performed to study hemodynamics. Plasma levels of superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde were measured. In addition, the dose of troponin I and activity of myeloperoxidase in serum and cardiac tissue were analyzed, and the histopathological findings were evaluated using light microscopy.

Results

Administration of KRG at a dose of 250 and 500 mg/kg recovered electrocardiographic changes, ejection fraction, fractional shortening, left ventricular systolic pressure, the maximal rate of change in left ventricle contraction (+dP/dt_max), and left ventricle relaxation (-dP/dt_max). In addition, KRG treatment significantly normalized the oxidative stress markers in plasma, dose dependently. In addition, the values of troponin I and myeloperoxidase were ameliorated by KRG treatment, dose dependently. And, KRG treatment showed better histopathological findings when compared with the DOX control group.

Conclusion

These mean that KRG mitigates myocardial damage by modulating the hemodynamics, histopathological abnormality, and oxidative stress related to DOX-induced cardiomyopathy in rats. The results of the present study show protective effects of KRG on cardiac toxicity.

Blood-Air Interface during Cardiopulmonary Bypass

The aim of this study was to compare the systemic blood activation with open and closed perfusion management during cardiopulmonary bypass. In 30 patients undergoing coronary artery bypass grafting, we prospectively studied systemic blood activation, blood loss and the need for donor blood. In 15 patients we used an open venous reservoir consisting of a hard shell venous reservoir with an integrated cardiotomy filter. In another 15 patients we used a totally closed venous reservoir consisting of a collapsible venous reservoir, no coronary suction, modified vent and cell saver. Venous blood samples were collected pre, post and 24 hours postoperatively. Sex, age and perfusion times were identical in both groups. There were no statistically significant differences in concentrations of FXIIa and C3a, amount of blood loss and need for donor blood. Interleukin-6 and Elastase levels showed trends toward a lesser inflammatory reaction in closed venous reservoir patients. Modification of perfusion management with optimized air management does not seem to be an effective strategy in reducing the inflammatory response and influencing the coagulation system in this small cohort.

Cyclosporine A in Reperfused Myocardial Infarction: The Multicenter, Controlled, Open-Label CYCLE Trial

BACKGROUND

Whether cyclosporine A (CsA) has beneficial effects in reperfused myocardial infarction (MI) is debated.

OBJECTIVES

This study investigated whether CsA improved ST-segment resolution in a randomized, multicenter phase II study.

METHODS

The authors randomly assigned 410 patients from 31 cardiac care units, age 63 ± 12 years, with large ST-segment elevation MI within 6 h of symptom onset, Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 to 1 in the infarct-related artery, and committed to primary percutaneous coronary intervention, to 2.5 mg/kg intravenous CsA (n = 207) or control (n = 203) groups. The primary endpoint was incidence of ≥70% ST-segment resolution 60 min after TIMI flow grade 3. Secondary endpoints included high-sensitivity cardiac troponin T (hs-cTnT) on day 4, left ventricular (LV) remodeling, and clinical events at 6-month follow-up.

RESULTS

Time from symptom onset to first antegrade flow was 180 ± 67 min; a median of 5 electrocardiography leads showed ST-segment deviation (quartile [Q]1 to Q3: 4 to 6); 49.8% of MIs were anterior. ST-segment resolution ≥70% was found in 52.0% of CsA patients and 49.0% of controls (p = 0.55). Median hs-cTnT on day 4 was 2,160 (Q1 to Q3: 1,087 to 3,274) ng/l in CsA and 2,068 (1,117 to 3,690) ng/l in controls (p = 0.85). The 2 groups did not differ in LV ejection fraction on day 4 and at 6 months. Infarct site did not influence CsA efficacy. There were no acute allergic reactions or nonsignificant excesses of 6-month mortality (5.7% CsA vs. 3.2% controls, p = 0.17) or cardiogenic shock (2.4% CsA vs. 1.5% controls, p = 0.33).

CONCLUSIONS

In the CYCLE (CYCLosporinE A in Reperfused Acute Myocardial Infarction) trial, a single intravenous CsA bolus just before primary percutaneous coronary intervention had no effect on ST-segment resolution or hs-cTnT, and did not improve clinical outcomes or LV remodeling up to 6 months. (CYCLosporinE A in Reperfused Acute Myocardial Infarction [CYCLE]; NCT01650662; EudraCT number 2011-002876-18).

Ginseng total saponin attenuates myocardial injury via anti-oxidative and anti-inflammatory properties

Background

Ginseng total saponin (GTS) contains various ginsenosides. These ginsenosides are widely used for treating cardiovascular diseases in Asian communities. The aim of this study was to study the effects of GTS on cardiac injury after global ischemia and reperfusion (I/R) in isolated guinea pig hearts.

Methods

Animals were subjected to normothermic ischemia for 60 minutes, followed by 120 minutes of reperfusion. GTS significantly increased aortic flow, coronary flow, and cardiac output. Moreover, GTS significantly increased left ventricular systolic pressure and the maximal rate of contraction (+dP/dt_max) and relaxation (−dP/dt_max). In addition, GTS has been shown to ameliorate electrocardiographic changes such as the QRS complex, QT interval, and RR interval.

Results

GTS significantly suppressed the biochemical parameters (i.e., lactate dehydrogenase, creatine kinase-MB fraction, and cardiac troponin I levels) and normalized the oxidative stress markers (i.e., malondialdehyde, glutathione, and nitrite). In addition, GTS also markedly inhibits the expression of interleukin-1β (IL-1β), IL-6, and nuclear factor-κB, and improves the expression of IL-10 in cardiac tissue.

Conclusion

These data indicate that GTS mitigates myocardial damage by modulating the biochemical and oxidative stress related to cardiac I/R injury.

Cardiovascular effects of resveratrol and atorvastatin treatments in an H2O2-induced stress model

Oxidative stress has been implicated in the pathophysiology of several types of cardiovascular disease (CVD). Statins are widely used to inhibit the progression of atherosclerosis and reduce the incidence of CVD. Certain over-the-counter products, including resveratrol, show similar effects to statins and may thus be used in conjunction with statins for the treatment of the majority of patients with CVD. The aim of the present study was to evaluate the effects of atorvastatin, resveratrol and resveratrol + atorvastatin (R+A) pretreatment on myocardial contractions and vascular endothelial functions in the presence of H₂O₂ as an experimental model of oxidative stress in rats. Four groups were established and referred to as the control, atorvastatin, resveratrol and R+A groups. Atorvastatin (40 mg/kg, per oral) and/or resveratrol (30 mg/kg, intraperitoneal) treatments were administered for 14 days. On the 15th day, the thoracic aortas and hearts of the rats were dissected and placed into isolated organ baths. Vascular responses to cumulative doses of H₂O₂ (1×10⁻⁸–1×10⁻⁴ M H₂O₂) with and without N (G)-nitro-L-arginine methyl ester (L-NAME) incubation were measured. In addition, myocardial electrical stimulation (ES) responses to various H₂O₂ concentrations (1×10⁻⁷–1×10⁻⁵ M H₂O₂) were evaluated. In the control and atorvastatin groups, H₂O₂ application caused a significant dose-dependent decrease in the ES-induced contractions in the myocardial tissue of rats. In the resveratrol and R+A groups, H₂O₂ application did not significantly affect myocardial contraction at any dose. In all groups, incubation with L-NAME caused a significant augmentation in the H₂O₂ response, revealing that this effect was mediated via the vascular endothelium. In conclusion, pretreatment with R+A for CVD appears to be superior to pretreatment with either agent alone.

Korean Red Ginseng Induced Cardioprotection against Myocardial Ischemia in Guinea Pig

This study was designed to evaluate the protective effect of Korean red ginseng (KRG) against ischemia/reperfusion (I/R) injury in isolated guinea pig heart. KRG has been shown to possess various ginsenosides, which are the major components of Panax ginseng. These components are known naturally occurring compounds with beneficial effects and free radical scavenging activity. The heart was induced to ischemia for 60 min, followed by 120 min reperfusion. The hearts were randomly allocated into five groups (n=8 for each group): normal control (N/C), KRG control, I/R control, 250 mg/kg KRG group and 500 mg/kg KRG group. KRG significantly increased hemodynamics parameters such as aortic flow, coronary flow and cardiac output. Moreover, KRG significantly increased left ventricular systolic pressure (LVSP), the maximal rate of contraction (+dP/dt_max) and maximal rate of relaxation (-dP/dt_max). Also, treatment of KRG ameliorated electrocardiographic index such as the QRS, QT and RR intervals. Moreover, KRG significantly suppressed the lactate dehydrogenase, creatine kinase-MB fraction and cardiac troponin I and ameliorated the oxidative stress markers such as malondialdehyde and glutathione. KRG was standardized through ultra performance liquid chromatograph analysis for its major ginsenosides. Taken together, KRG has been shown to prevent cardiac injury by normalizing the biochemical and oxidative stress.

Protective ischaemia in patients: preconditioning and postconditioning

Infarct size can be limited by reducing the determinants of infarct size or increasing collateral blood flow by treatment initiated before the ischaemic event. Reperfusion is the definitive treatment for permanently reducing infarct size and restoring some degree of contractile function to the affected myocardium. Innate survival mechanisms in the heart can be stimulated by short, non-lethal periods of ischaemia and reperfusion, applied either before or after the ischaemic event. Preconditioning, a series of transient intervals of ischaemia and reperfusion applied before the lethal 'index' ischaemic event, sets in motion molecular and cellular mechanisms that increase cardiomyocyte survival to a degree that had not hitherto been seen before. The cardioprotective ischaemic-reperfusion protocol applied at onset of reperfusion, termed 'postconditioning' (Postcon), is also associated with significant cardioprotection that can be applied at the point of reperfusion treatment in the catheterization laboratory or operating room. Both preconditioning and Postcon have been successfully applied to the clinical setting and have been found to reduce infarct size and other attributes of post-ischaemic injury. This review will summarize the physiological preclinical data on preconditioning and Postcon that are relevant to their translation to clinical therapeutics and treatment.

Cardioprotective effect of resvaratrol pretreatment on myocardial ischemia–reperfusion induced injury in rats

OBJECTIVE

The major objective of the present study was to examine the cardioprotective effect of resveratrol, an antioxidant presents in red wine, in the rat after ischemia-reperfusion (I/R).

DESIGN

The left coronary artery was in occlusion for 30 min followed by a 120 min reperfusion in anesthetized rats. Animals were pretreated with and without resveratrol before occlusion. The post-ischemic ventricular function (left ventricle maximum systolic pressures and the maximal first derivative of developed pressure) and myocardial infarct size and myocardial nitric oxide (NO) and malonaldehyde (MDA) content were compared.

RESULTS

Resveratrol pretreatment had dramatic cardioprotective effects on post-ischemic ventricular functional recovery and decreasing myocardial infarct size. Resveratrol pretreatment also increased NO and decreased MDA content in myocardium.

CONCLUSIONS

Resveratrol has cardioprotective properties in I/R rats. The cardioprotective effects in the I/R rats may be correlated with its antioxidant activity and upregulation of NO production.

Cardioprotection with resveratrol pretreatment: improved beneficial effects over standard treatment in rat hearts after global ischemia

OBJECTIVE

The major objective of the present study is to evaluate the potential role of resveratrol (RVT), a natural antioxidant found in grapes and red wine, in protecting the myocardium from the deleterious effects of ischemia-reperfusion (I/R) injury using isolated rat hearts.

METHODS

Langendorff perfused isolated rat hearts were subjected to 60 min of global ischemia following 60 min of reperfusion. RVT was given according to chronic pretreatment and/or acute treatment protocols. Animals received RVT at the dose of 20 mg/kg via an intragastric tube for 14 days before the experiment and/or at the infusion concentration of 10 microM for 30 min before the onset of ischemia. The myocardial postischemic recovery was compared using hemodynamic data (peak systolic pressure, end diastolic pressure, and +dP/dtmax), coronary flow, biochemical parameters (LDH, CK-MB, cTnI, myoglobin) from coronary effluent, and oxidative stress markers (MDA, GSH, carbonyl) from heart tissue homogenates in each group.

RESULTS

RVT pretreatment and treatment protocols have provided increased preservation in myocardial recovery following global ischemia compared to a non-treated group. Furthermore, the ischemic damage of myocardium was significantly lower in chronic pretreated rats than in the acutely treated group. In contrast, no significant difference was observed in cardioprotective effects of RVT between the only pretreated group, and both the pretreated and treated group throughout reperfusion.

CONCLUSION

The findings from this study indicate that RVT has potent cardioprotective properties against I/R injury in rat hearts. The study also highlighted that the administration of RVT, as pretreatment, has amplified the beneficial effects over the standard treatment.

The effect of a low molecular weight inhibitor of lipid peroxidation on ultrastructural alterations to ischemia-reperfusion in the isolated rat heart

The effects of H290/51, a novel indenoindole derivative inhibitor of lipid peroxidation, on ultrastructural changes during cardiac ischemia-reperfusion injury were investigated. Langendorff-perfused rat hearts were exposed to 30 minutes of global ischemia followed by 20 minutes of reperfusion: Group A: Control hearts with standard buffer perfusion with vehicle added. Group B: H290/51 (10(-6) mol/l) added to buffer throughout stabilisation and reperfusion. In an additional Group C, where hearts were given H290/51, but not subjected to ischemia, the ultrastructure was preserved till the end of reperfusion. Absolute volumes and calculated volume fractions (Vv) of tissue and subcellular components were assessed with quantitative stereologic morphometry. After ischemia the increase in volume of extracellular interstitium was inhibited by H290/51 (247 +/- 80 vs. 159 +/- 50 microl, mean +/- SD, groups A and B, respectively, p<0.05). The Vv (interstitium/myocard) was higher in control hearts (0.318 +/- 0.062 vs. 0.206 +/- 0.067, p<0.05). Vv (cell edema/myocyte) was higher in the control group (0.144 +/- 0.07 vs. 0.083 +/- 0.033, p<0.05). Vv (myocyte/myocard) was higher in group B after ischemia than in the control group (0.622 +/- 0.071 vs. 0.707 +/- 0.052, p<0.05). The decreased Vv (capillary/myocard) after ischemia was inhibited by H290/51. After reperfusion there was no difference between groups. Treatment with H290/51 reduced edema and ensured better preserved sarcolemmal membrane structure during ischemia. The effect was no longer present after reperfusion.

Beneficial effects of astringinin, a resveratrol analogue, on the ischemia and reperfusion damage in rat heart

Oxidative stress plays an important role in the pathogenesis of myocardial ischemia and infarction. Antioxidants might then be beneficial in the prevention of these diseases. Astringinin (3,3',4',5-tetrahydroxystilbene), a resveratrol (3,4',5-trihydroxystilbene) analogue with considerably higher antioxidative activity and free radical scavenging capacity, was introduced to examine its cardioprotective effects in ischemia or ischemia-reperfusion (I/R) rats. In the present study, the left main coronary artery was occluded by the following procedures: (i) 30 min occlusion, (ii) 5 min occlusion followed by 30 min reperfusion, and (iii) 4 h occlusion. Animals were infused with and without astringinin before coronary artery occlusion. Mortality, and the severity of ischemia- and I/R-induced arrhythmias were compared. Pretreatment of astringinin dramatically reduced the incidence and duration of ventricular tachycardia (VT) and ventricular fibrillation (VF) during either ischemia or I/R period. Astringinin at 2.5 x 10(-5) and 2.5 x 10(-4) g/kg completely prevented the mortality of animals during ischemia or I/R. During the same period, astringinin pretreatment also increased nitric oxide (NO) and decreased lactate dehydrogenase (LDH) levels in the carotid blood. In animals subjected to 4 h coronary occlusion, the cardiac infarct size (expressed as a percentage of occluded zone) was reduced from 44.4 + or - 4.1% to 19.1 + or - 2.4% by astringinin (2.5 x 10(-4) g/kg). We conclude that, astringinin is a potent antiarrhythmic agent with cardioprotective activity in ischemic and ischemic-reperfused rat heart. The beneficial effects of astringinin in the ischemic and ischemic-reperfused hearts may be correlated with its antioxidant activity and upregulation of NO production.