Pharmacological Postconditioning Research Articles

Protective effects of fructose-1,6-bisphosphate postconditioning on myocardial ischemia-reperfusion injury in patients undergoing valve replacement：a randomized, double-blind, placebo-controlled clinical trial.

Pharmacological postconditioning can protect against myocardial ischaemia-reperfusion injury during cardiac surgery with extracorporeal circulation. The aim of this study was to observe the protective effects of fructose-1, 6-bisphosphate (FDP) postconditioning on myocardial ischaemia-reperfusion injury in patients undergoing cardiac valve replacement with extracorporeal circulation. Patients undergoing elective mitral valve replacement and/or aortic valve replacement were divided into normal saline postconditioning group (NS group) and FDP postconditioning group (FDP group). The primary outcome was the plasma concentration of creatine kinase-MB (CK-MB). The secondary outcomes were the plasma concentrations of lactate dehydrogenase (LDH), creatine kinase (CK), high-sensitivity C-reactive protein (hs-CRP), alpha-hydroxybutyrate dehydrogenase (α-HBDH) and cardiac troponin I (cTnI), the spontaneous cardiac rhythm recovery profile, the extracorporeal circulation time and duration of surgery, ICU and postoperative hospitalization. Forty patients were randomly assigned to receive intervention and included in the analysis. The serum concentrations of CK-MB, LDH, CK, cTnI, α-HBDH and hs-CRP at T1∼4 were lower in the FDP group than in the NS group (P < 0.001). Compared with the NS group, the dosage of dopamine administered 1∼90min after cardiac resuscitation, the spontaneous cardiac rhythm recovery time and the incidence of ventricular fibrillation were lower in the FDP group (P < 0.001, P < 0.001 and P = 0.040, respectively). The values of ST- changes were increased more significantly in the NS group than in the FDP group （median [standard deviation] 1.3 [0.3] mm vs 0.7 [0.2] mm）(P < 0.001). Compared with the NS group, the time of recovery of ST-segment deviations was shorter in the FDP group（50.3 [12.3] min vs 34.6 [6.9] min） (P < 0.001). The fructose-1, 6-bisphosphate postconditioning could improve both myocardial ischaemia-reperfusion injury and the spontaneous cardiac rhythm recovery during cardiac valve surgery with extracorporeal circulation.

Four to seven year follow-up of pharmacological postconditioning with mangafodipir as an adjunct to primary PCI in ST-segment elevation myocardial infarction.

Adverse left ventricular remodelling (AR) develops over time in approximately 30 % of patients with a history of coronary artery disease. AR manifests as a structural change in the left ventricle (LV) in terms of increased volumes and reduced left ventricular ejection fraction (LVEF). Manganese dipyridoxyl diphosphate (mangafodipir) has demonstrated interesting cardioprotective features in acute myocardial ischemia. Pharmacological postconditioning (PP) with mangafodipir as an adjunct to primary percutaneous coronary intervention may possibly reduce the development of AR over time in ST-elevation myocardial infarction (STEMI). The aim of this four to seven year follow-up study is to investigate the potential benefits of PP with mangafodipir in STEMI patients. Thirteen out of the initial twenty patients that were included in the primary study of Karlsson et al. were followed up between April and June 2017. The study group underwent review of the hospital records, a clinical examination with ECG and blood sample analysis before cardiac magnetic resonance examination of the patient. LVEF, left ventricular diastolic volume, left ventricular end systolic volume, LV mass and myocardial strain in all directions were computed. The PP group showed a decrease in LV volume, mass and higher LVEF at follow-up (p < 0.05) while the individual response of the placebo group showed features that are seen in AR. Although there was no difference in myocardial strain, measurement for the PP-group was higher in absolute terms. Pharmacological postconditioning with mangafodipir in STEMI demonstrated cardioprotective features compared to the placebo group at follow-up. This article is protected by copyright. All rights reserved.

Pharmacological Postconditioning by Protocatechuic Acid Attenuates Brain Injury in Ischemia–Reperfusion (I/R) Mice Model: Implications of Nuclear Factor Erythroid-2-Related Factor Pathway

Ischemia–reperfusion (I/R) injury often follows cardiovascular aberrations that predispose the patient to be neurological and cognitive abnormalities. Pharmacological postconditioning (pPoCo) aims to mitigate I/R origin cerebral infarction and neurobehavioral impairment. Protocatechuic acid (PCA) is a natural polyphenol possessing anti-oxidant and anti-inflammatory activities. This study investigated the effects of PCA pPoCo using a global I/R mice prototype. Mice were injected PCA (50 and 100 mg/kg) immediately after bilateral common carotid artery occlusion (17 min) followed by 24 h reperfusion. Trigonelline (10 mg/kg) was administered separately before I/R surgery to assess the role of the Nrf2 pathway in PCA and I/R treated mice. Results displayed neurological deficits 24 h post-reperfusion, and I/R triggered sensorimotor and memory deficits that were attenuated by PCA. PCA pPoCo increased antioxidants and Nrf2 expression in the brain against I/R injury. In I/R mice, PCA pPoCo attenuated lipid peroxidation, inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6), and myeloperoxidase activity. Histopathology revealed a decrease in total infarct area (TTC staining) and cortical neuron density by I/R surgery that was attenuated by PCA. Trigonelline antagonized beneficial effects of PCA pPoCo and attenuated Nrf2 pathway in I/R mice model. PCA pPoCo dose-dependently improves neurobehavioral functions against global I/R injury via the Nrf2 mechanism.

Majonoside-R2 Postconditioning Protects Cardiomyocytes Against Hypoxia/Reoxygenation Injury by Attenuating the Expression of HIF1α and Activating RISK Pathway.

Reoxygenation of hypoxic cardiac myocytes can paradoxically induce myocardial injury and affect the recovery processes. Pharmacological postconditioning is an efficient strategy used in clinical practice that protects cardiomyocytes from hypoxia/reoxygenation (HR) injury. Natural products or foods have been known to possess effective cardioprotective properties. Majonoside-R2 (MR2) is a dominant saponin component of Vietnamese ginseng that has several biological effects. In this study, we evaluated the protective effect of MR2 on HR-stimulated cardiomyocytes and investigated the related molecular mechanisms. H9C2 cardiomyocytes were exposed to HR conditions with or without MR2 supplementation. Samples from experimental groups were used to analyze the expression of apoptosis- and activating reperfusion injury salvage kinase (RISK)-related factors in response to HR injury by using enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blotting. Post-treatment, MR2 enhanced cell viability under HR conditions. We found that MR2 suppressed the expression of hypoxia-inducible factor 1-alpha (HIF1α) and transforming growth factor beta 1 (TGFβ1), modulated Akt/GSK3ß/cAMP response element-binding signaling, and regulated gene expression related to apoptosis (B cell lymphoma-extra-large [Bcl-xl], Bcl-2 homologous killer [Bak], Bcl-2 associated X [Bax], and connexin 43 [Cnx43]). Thus, the present findings demonstrate that MR2 protects cardiomyocytes against HR injury by suppressing the expression of HIF1α and activating the RISK pathway.

Neuroprotective potential of Hesperetin pharmacological postconditioning against cerebral ischemic reperfusion injury in mice

Cerebral ischemic reperfusion injury results in neuronal destruction during the period of ischemia due to the deprivation of oxygen and energy. Pharmacological post conditioning is playing road map for neuroprotection. The present study has been designed to investigate the neuroprotective potential of Hesperetin-pharmacological post-conditioning against cerebral ischemic reperfusion injury in mice.

Pharmacological postconditioning with sappanone A ameliorates myocardial ischemia reperfusion injury and mitochondrial dysfunction via AMPK-mediated mitochondrial quality control

Pharmacological postconditioning (PPC), drug intervention before or during the early minutes of reperfusion, could stimulate cardioprotection as ischemic postconditioning. In this study, we examined whether PPC with sappanone A (SA), a homoisoflavanone with potent antioxidant and anti-inflammatory activity, has a protective effect on myocardial ischemia reperfusion injury (MIRI), and explored the underlying mechanism. A MIRI model was established using the Langendorff method. After 30 min of ischemia, isolated rat hearts were treated with SA at the onset of reperfusion to stimulate PPC. The changes in myocardial infarct size, mitochondrial function, mitochondrial biogenesis, mitophagy, and mitochondrial fission and fusion were detected. The results showed that SA postconditioning decreased the myocardial infarct size, inhibited the release of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), and cardiac troponin (cTnI), as well as improved cardiac function, enhanced myocardial ATP content and mitochondrial complex activity, and prevented the loss of mitochondrial membrane potential and opening of mitochondrial permeability transition pore (mPTP). Mechanistically, we found that SA was an AMP-activated protein kinase (AMPK) activator, and SA postconditioning could facilitate mitochondrial biogenesis by increasing mitochondrial DNA (mtDNA) copy number and the expression of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α). In addition, it balanced mitochondrial dynamics by decreasing fission and increasing fusion, and enhanced mitophagy in an AMPK-dependent manner. Moreover, AMPK silencing abolished the cardioprotection of SA postconditioning. Collectively, our study demonstrated that SA postconditioning ameliorated MIRI and mitochondrial dysfunction by regulation of mitochondrial quality control via activating AMPK. This finding provides a new insight into pharmacological action and clinical use of SA.

PND55 Protocatechuic Acid Induced Pharmacological Postconditioning Ameliorates Cerebral Ischemia Reperfusion Injury in MICE By Modulation of Nuclear Factor Erythroid 2-Related Factor Pathway

PND55 Protocatechuic Acid Induced Pharmacological Postconditioning Ameliorates Cerebral Ischemia Reperfusion Injury in MICE By Modulation of Nuclear Factor Erythroid 2-Related Factor Pathway

Dexmedetomidine Provides Cardioprotection During Early or Late Reperfusion Mediated by Different Mitochondrial K+-Channels.

Cardioprotective interventions-such as pharmacological postconditioning-are a promising strategy to reduce deleterious consequences of ischemia and reperfusion injury (I/RI) in the heart, especially as timing and onset of myocardial infarction are unpredictable. Pharmacological postconditioning by treatment with dexmedetomidine (Dex), an α2-adrenoreceptor agonist, during reperfusion protects hearts from I/RI, independently of time point and duration of application during the reperfusion phase. The mitochondrial ATP-sensitive K (mKATP) and mitochondrial large-conductance calcium-sensitive potassium channel (mBKCa) play a pivotal role in mediating this cardioprotective effect. Therefore, we investigated whether Dex-induced cardioprotection during early or late reperfusion is mediated variously by these mitochondrial K-channels. Hearts of male Wistar rats were randomized into 8 groups and underwent a protocol of 15 minutes adaption, 33 minutes ischemia, and 60 minutes reperfusion in an in vitro Langendorff-system. A 10-minute treatment phase was started directly (first subgroup, early reperfusion) or 30 minutes (second subgroup, late reperfusion) after the onset of reperfusion. Control (Con) hearts received vehicle only. In the first subgroup, hearts were treated with 3 nM Dex, 100 µM mKATP-channel blocker 5-hydroxydecanoate (5HD) or 1 µM mBKCa-channel blocker Paxilline (Pax) alone or with respective combinations (5HD + Dex, Pax + Dex). Hearts of the second subgroup received Dex alone (Dex30') or in combination with the respective blockers (5HD + Dex30', Pax + Dex30'). Infarct size was determined with triphenyltetrazoliumchloride staining. Hemodynamic variables were recorded during the whole experiment. During early reperfusion (first subgroup), the infarct size reducing effect of Dex (Con: 57% ± 9%, Dex: 31% ± 7%; P< .0001 versus Con) was completely abolished by 5HD and Pax (52% ± 6%; Pax + Dex: 53% ± 4%; each P< .0001 versus Dex), while both blockers alone had no effect on infarct size (5HD: 54% ± 8%, Pax: 53% ± 11%). During late reperfusion (second subgroup) the protective effect of Dex (Dex30': 33% ± 10%, P< .0001 versus Con) was fully abrogated by Pax (Pax + Dex30': 58% ± 7%, P < .0001 versus Dex30'), whereas 5HD did not block cardioprotection (5HD + Dex30': 36% ± 7%). Between groups and within each group throughout reperfusion no significant differences in hemodynamic variables were detected. Cardioprotection by treatment with Dex during early reperfusion seems to be mediated by both mitochondrial K-channels, whereas during late reperfusion only mBKCa-channels are involved.

INFLUENCE OF TRIMETAZIDINE AND LEVOCARNITINE ON CLINICAL COURSE, STRUCTURAL AND FUNCTIONAL CHANGES AND MYOCARDIAL FIBROSIS IN PATIENTS WITH MYOCARDIAL INFARCTION

Introduction: Modern strategies of STEMI/NSTEMI management, that include revascularization by coronary stenting, bypass grafting, nowadays are used in 30-40% of urgent patients of such category. The prevalent part of patients is treated by administration of the optimal drug therapy. The aim of the research was to study the influence of trimetazidine and levocarnitine on the clinical course of STEMI/NSTEMI. Materials and methods: 100 patients with STEMI/NSTEMI were included into the research. Depending on the therapy scheme, patients were divided into three groups and the control one. Determination of the key parameters was performed initially after hospitalization and at the day of patient discharge. Results: Promising results were shown while slowing the myocardial fibrosing. Limiting of the infarcted and `stunned` myocardium area resulted in ejection fraction increase, increase of the myocardial reserve, measured by echocardiographic indexes. Conclusions: Decreasing of myocardial fibrosing can be potentiated by the pharmacological postconditioning as well as limiting of the necrotic myocardium area and increase of viable myocardium area. Pharmacological postconditioning is effective and save, that can be proved by the absence of any serious complications.

Effects of resveratrol postconditioning on cerebral ischemia in mice: role of the sirtuin-1 pathway.

Evidence has demonstrated that resveratrol preconditioning exhibits neuroprotection against cerebral ischemia-reperfusion (IR) injury. The current investigation aimed to explore whether pharmacological postconditioning, by administering resveratrol, after a sustained ischemia and prior to prolonged reperfusion abrogates cerebral IR injury. Cerebral IR-induced injury mice model was employed in this study to evaluate the neuroprotective effects of pharmacological postconditioning with resveratrol (30 mg/kg; i.p.) administered 5 min before reperfusion. We administered sirtinol, a SIRT1/2 selective inhibitor (10 mg/kg; i.p.) 10 min before ischemia (17 min) and reperfusion (24 h), to elucidate whether the neuroprotection with resveratrol postconditioning depends on SIRT1 activation. Various biochemical and behavioural parameters and histopathological changes were assessed to examine the effect of pharmacological postconditioning. Infarct size is estimated using TTC staining. It was established that resveratrol postconditioning abrogated the deleterious effects of IR injury expressed with regard to biochemical parameters of oxidative stress (TBARS, SOD, GSH), acetylcholinesterase activity, behavioural parameters (memory, motor coordination), infarct size, and histopathological changes. Sirtinol significantly reversed the effect of resveratrol postconditioning. We conclude that induced neuroprotective benefits of resveratrol postconditioning may be the consequence of SIRT1 activation and resveratrol can be considered, for further studies, as potential agent inducing pharmacological postconditioning in clinical situations.

The Protective Effects of Pharmacologic Postconditioning of Hydroalcoholic Extract of Nigella sativa on Functional Activities and Oxidative Stress Injury During Ischemia-Reperfusion in Isolated Rat Heart.

Oxidative stress is known to act as the trigger of cardiac damage during ischemia-reperfusion (I/R) injury. Postconditioning (PoC) is employed to minimize the consequences of ischemia at the onset of reperfusion. Regarding the well-known antioxidant properties of Nigella sativa (Ns), the aim of this study was to investigate whether Nigella sativa postconditioning (Ns-PoC) could reduce IRI by lowering the formation of reactive oxygen species (ROS). Isolated rat hearts were perfused with the Langendorff apparatus, which were subjected to 20min of preperfusion, 20min of global ischemia, followed by 40min of reperfusion. At the onset of reperfusion, based on the type of intervention group, a 10-min period of Krebs flow was developed along with the treatment, and then the reperfusion with Krebs solution was conducted for 30 min. Heart rate (HR) and left ventricular pressure (LVP) were recorded by isometric transducers connected to a data acquisition system. Thiobarbituric acid reactive substances (TBARS), 4-hydroxynonenal (4-HNE) levels, total thiol groups (-SH) levels, superoxide anion dismutase (SOD), and catalase (CAT) activities in myocardial tissues were detected to evaluate the oxidative stress damage degree. Ns-PoC significantly improved cardiodynamic parameters including left ventricular developed pressure (LVDP), rate pressure product (RPP), and the maximum up/down rate of the left ventricular pressure (± dp/dt) as well as SH groups, SOD, and CAT activities. Moreover, it decreased MDA and 4-HNE levels during early reperfusion. The results of this study showed that Ns-PoC ameliorated cardiac functions in isolated rat heart during I/R injuries by improving myocardial oxidative stress states, which may be related to the antioxidant effect of Ns.

Influence of Adenosine-5-Triphosphogluconate-Magnesium Trisodium Salt and Levocarnitine on Clinical Course, Structural and Functional Changes and Myocardial Fibrosis in Patients with Myocardial Infarction

Modern strategies of STEMI/NSTEMI management, that include revascularization by coronary stenting, bypass grafting, nowadays are used in 30-40% of urgent patients of such category. The prevalent part of patients is treated by administration of the optimal drug therapy.&#x0D; The objective of the research was to study the influence of adenosine-5-triphosphogluconate-magnesium trisodium salt and levocarnitine on the clinical course of STEMI/NSTEMI.&#x0D; Materials and methods. 100 patients with STEMI/NSTEMI were included into the research. Depending on the therapy scheme, patients were divided into three groups and the control one. Determination of the key parameters was performed initially after hospitalization and at the day of patient discharge.&#x0D; Results. Promising results were shown while slowing the myocardial fibrosing. Limiting of the infarcted and `stunned` myocardium area resulted in ejection fraction increase, increase of the myocardial reserve, measured by echocardiographic indexes.&#x0D; Conclusions. Decreasing of myocardial fibrosing can be potentiated by the pharmacological postconditioning as well as limiting of the necrotic myocardium area and increase of viable myocardium area. Pharmacological postconditioning is effective and save, that can be proved by the absence of any serious complications.

Pulsatile antagonism on bradykinin 2-receptor (BK2R) by icatibant triggers the most effective kinin-dependent post-conditioning on rat hearts.

Pharmacological post-conditioning (PC) by intermittent but not continuous administration of exogenous bradykinin (BK) reduces ischemia/reperfusion (I/R) injury via the Reperfusion Injury Salvage Kinase (RISK) pathway activation. We evaluated whether intermittent administration with icatibant (HOE140), a BK2R antagonist, may represent an effective PC strategy, with the advantage of limiting the potential risks of supra-physiologic BK activity. Hearts from male Sprague-Dawley (SD) rats on a Langendorff system were exposed to I/R injury (30/120 min). BK (100 nM) and HOE140 (1 µM) were administered post-ischemically during the first 3 min of reperfusion, under continuous or intermittent infusion (10 s/each). Hearts were randomly assigned to 5 groups: 1) I/R alone (n=5); 2) continuous HOE140 (cHOE n=6); 3) intermittent HOE140 (iHOE n=6); 4) continuous BK (cBK n=6); 5) intermittent BK (iBK n=6). End-diastolic left ventricular pressure (LVEDP), developed left ventricular pressure (dLVP) and coronary flow (CF) were monitored throughout reperfusion. Left ventricular infarct mass (IM) was quantified together with the phosphorylated levels of Akt and GSK3β (RISK pathway kinases) at the end of reperfusion. IM was not significantly changed in cBK or cHOE groups (vs. I/R). Conversely, both iBK and iHOE groups showed a significant limitation in IM (vs. I/R, p<0.05, p<0.01, respectively). Akt and GSK3β phosphorylation levels were higher in iBK and iHOE groups (vs. I/R, p<0.05). When compared to I/R group, both LVEDP values (p<0.05, first 60-min reperfusion), as well as dLVP values (p<0.01) were improved only in iHOE group. CF values did not vary among all groups. In isolated rat hearts, intermittent modulation of the endogenous kallikrein-kinin system by a selective BK2R antagonist mediates PC cardioprotection via RISK signaling.

Neuroprotective effect of pharmacological postconditioning on cerebral ischaemia-reperfusion-induced injury in mice.

To investigate the mechanism of neuroprotection rendered via pharmacological postconditioning in cerebral ischaemia-reperfusion-induced injury in mice. Pharmacological postconditioning is strategy which either involves hindering deleterious pathway or inducing modest stress level which triggers intracellular defence pathway to sustain more vigorous insult leading to conditioning. Hence, in current research we explored the potentiality of CGS21680 (0.5 mg/kg; i.p), an adenosine A2 A receptor agonist and PTEN inhibitor, SF1670 (3 mg/kg; i.p.) to trigger postconditioning after inducing cerebral global ischaemia (17 min) and reperfusion (24 h)-induced injury via occlusion of both carotid arteries. Mice were also given treatment with LY294002 (1.5 mg/kg; i.p.), a PI3K inhibitor and adenosine A2 A receptor antagonist, Istradefylline (2 mg/kg; i.p.), to establish the precise mechanism of postconditioning. Various biochemical and behavioural parameters were assessed to examine the effect of pharmacological postconditioning. Pharmacological postconditioning induced with CGS21680 and SF1670 attenuated the infarction along with improved behavioural and biochemical parameters in comparison with ischaemia-reperfusion control group. The outcome of postconditioning with CGS21680 and SF1670 was significantly reversed by LY294002 and Istradefylline, respectively. The neuroprotective effects of CGS21680 and SF1670 postconditioning on cerebral ischaemia-reperfusion injury may be due to PI3K/Akt pathway activation.

Possible role of ATP-sensitive potassium and MPTP channels in pharmacological postconditioning in mouse brain

Background: Brief episodes of ischemia reperfusion in form of post conditioning when given after prolong ischemia found to be beneficial in various models of I/R injury. Opening of KATP & closing of MPTP has been reported provide cardioprotection against I/R injury.

Role of intra-aortic morphine in post conditioning during valvular surgery with low ejection fraction

BackgroundThe application of cardioplegia does not completely eradicate myocardial ischemia in cardiac/reperfusion injury due to cardiac arrest. Post conditioning is novel strategy of attaining cardioprotection. Pharmacological post conditioning using a drug as morphine administered before reperfusion would protect the heart against ischemia-reperfusion injury. We investigated whether intra-aortic morphine administration has a post conditioning effect on patients with low ejection fraction (EF) undergoing valve surgery. MethodsThis prospective randomized controlled trial in a single center involved one hundred patients scheduled for elective valve surgery were divided into two groups: the Post conditioning group and the Control group. The Post conditioning group (n = 50) received a dose of morphine (0.1 mg/kg) diluted in 20 ml normal saline, injected via a cardioplegia needle into the aortic root with warm hotshot before aortic cross-clamp removal while the control group (n = 50) received the same volume of saline without morphine. Both groups received antegrade warm blood cardioplegia. To assess results EF, fractional shortening (FS), troponin level, ABG, inotropes, postoperative ventilation time, and length of ICU stay were assessed. ResultsPostoperative EF and FS revealed a statistically significant higher readings in the Post conditioning group. A significant reduction in the troponin levels was recorded in the study group than the control group. Duration of postoperative ventilation and length of ICU stay were statistically lesser in the Post conditioning group. ConclusionsMorphine administration immediately with warm hotshot was related to improvement in the cardiopulmonary function, less inotropic drug use, and higher left ventricular EF.

Preconditioning and postconditioning: from bench to bedside

Coronary heart disease (CHD) is the leading cause of death world-wide. Since 1990, more people in the world have diedfrom CHD than from any other disease (World Health Organisation, WHO). “Conditioning” the heart to render it more resistant to the detrimental effects of acute ischaemia-reperfusion injury harnesses the endogenous ability of the heart to protect itself. This can be achieved using various mechanical strategies including the application of brief episodes of ischaemia and reperfusion to either the heart itself (ischaemic preconditioning) or an organ/tissue remote from the heart (remote ischaemic preconditioning) prior to the sustained ischaemic insult. Importantly, this form of protection can be mimicked by pharmacological agents capable of recapitulating the protective effect of IPC(pharmacological preconditioning). Preconditioning-induced cardioprotection is clearly restricted to patients undergoing an anticipated ischaemic insult such as in patients undergoing cardiac surgery. In contrast, the other major form of “conditioning” termed postconditioning can be implemented in patients presenting with an acute myocardial infarction after the onset of the sustained ischaemic insult. In this setting, myocardial reperfusion is interrupted with intermittent short-lived episodes of myocardial ischaemia applied to the heart itself (ischaemic postconditioning) or an organ or tissue remote from the heart (remote ischaemic postconditioning) – an effect which can again be mimicked by pharmacological agents (pharmacological postconditioning).This article will briefly review these various forms of“conditioning” examining the underlying mechanistic pathways and their clinical application.

Adenosine triphosphate postconditioning is associated with better preserved global and regional cardiac function during myocardial ischemia and reperfusion: a speckle tracking imaging-based echocardiologic study.

Effects of ischemic postconditioning (IPostC) and adenosine triphosphate (ATP)-mediated pharmacologic postconditioning (ATP-PPostC) on cardiac function were evaluated by speckle tracking imaging (STI)-based echocardiography. A myocardial I/R model was induced in rabbits by reversible ligation of the left ventricular branch of coronary artery. Rabbits were randomized into three groups: ischemia and reperfusion (IR) (no further intervention), IPostC, and ATP-PPostC groups. Cardiac function was evaluated by conventional and STI-based echocardiography. Myocardial necrosis, apoptosis, and myocardial mRNAs of apoptosis-related proteins (Bcl-2 and Bax) were evaluated. Speckle tracking imaging (STI)-based echocardiography revealed that IPostC and ATP-PPostC were associated with better preserved global and regional cardiac function, as indicated by significantly increased GLSrsys, GLSrd, GLSsys, SrLsys, SrLd, and SLsys in both groups (all P<.5). Subsequent pathologic studies indicate that the percentage of necrotic myocardium and permillage of apoptotic cells were significantly lower in the IPostC and ATP-PPostC groups than in the IR group (all P<.05). Moreover, both IPostC and ATP-PPostC were associated with increased Bcl-2 mRNA levels and reduced Bax mRNA levels. IPostC and ATP-PPostC may exert cardioprotective functions by better preservation of cardiac function during the I/R process and at least partly via attenuation of myocardial apoptosis.

Inhibition of ceramide de novo synthesis as a postischemic strategy to reduce myocardial reperfusion injury.

The injury caused by myocardial reperfusion after ischemia can be contained by interventions aimed at reducing the inflammation and the oxidative stress that underlie exacerbation of tissue damage. Sphingolipids are a class of structural and signaling lipid molecules; among them, the inflammation mediator ceramide accumulates in the myocardium upon ischemia/reperfusion. Here, we show that, after transient coronary occlusion in mice, an increased de novo ceramide synthesis takes place at reperfusion in the ischemic area surrounding necrosis (area at risk). This correlates with the enhanced expression of the first and rate-limiting enzyme of the de novo pathway, serine palmitoyltransferase (SPT). The intraventricular administration at reperfusion of myriocin, an inhibitor of SPT, significantly protected the area at risk from damage, reducing the infarcted area by 40.9 % relative to controls not treated with the drug. In the area at risk, myriocin downregulated ceramide, reduced the content in other mediators of inflammation and reactive oxygen species, and activated the Nrf2-HO1 cytoprotective response. We conclude that an enhanced ceramide synthesis takes part in ischemia/reperfusion injury and that myriocin treatment can be proposed as a strategy for myocardial pharmacological postconditioning.

Pharmacological postconditioning by sevoflurane during cardiac surgery

Optimization of myocardial protection during cardiac surgery with a long period of anoxia infarction using sevoflurane postconditioning of myocardium. to develop the optimal pharmacological postconditioning protocol with sevoflurane for infarction patients ,undergoing cardiac surgery. Two groups were formedfor this study: CON] 00 (n-32) with aortic cross-clamping time 114±15 min and SEV100 group (n-34), where the myocardium anoxia was 119±22 minutes. According to previously developed in the pilot study Protocol, we added sevofturane in the circuit of extracorporeal circulation in a dose of 2.0 vol. % 20 minutes before removing the clamp from the aorta and the first 20 min of reperfusion in the group SE V100. In the group CON1 00 pharnacological postconditioning wasn't conducted. To assess the adequacy of the cardioprotection against ischemic damage in operated patients, we used the following clinical and laboratory parameters: changing the level of troponin T; the concentration of lactate and glucose as a marker of severity of anaerobic metabolism; concentration of proinflammatory cytokines IL-6, IL-8, TNF-alpha in blood serum as reperfusion injury markers. Also we used the registration of central hemodynamics data: measuring the mean invasive blood pressure; central venous pressure; Cardiac output was measured by the method of transesophageal echocardiography TEEcho-CG, calculated left ventricular ejection fraction by Simpson. We evaluated the clinical course of the perioperative period: incidence ofperioperative myocardial ischemia; the need and the duration ofuse of cardiotonic drugs in the perioperative period; the incidence of reperfusion arrhythmias; the frequency of self-recovery heart rate. According to the results of anaerobic metabolism markers, we can conclude that the period of the myocardium anoxia ofpatients in both groups experienced no significant difference. However; a completely different pattern was observed when comparing the proinflammatory cytokines, such as IL-6, IL-8, TNF-a. This confirms that the group SEV] 00 survived the reperfusion is much better than the group CON100. Instrumental examination also showed that the group ofpatients in which pharmacological postconditioning with sevofturane was held signficantly better suffered ischemia and reperfiision injury compared to control group. Self-recovery heart rate after removing the aorta clamp in the group CON100 was observed in 81%, in group SEV100 same - 93%. Similarly, the frequency of myocardial ischemia episodes on the ECG in reperfusion period was two times lower in the group SEV100 compared with group CON100 - 5.8% and 12.5% respectively. Reperfusion arrhythmia is almost 3 times more frequent in the group CON100 - 21,8%, in the group SEV100, where he conducted pharmacological postconditioning with sevoflurane is 8.8%.. Combined with sevoflurane cardioprotection FPC has a much better resistance to myocardial ischemia-reperfusion injury in patients with myocardial infarction time over 100 minutes than monoprotection with cardioplegic solution "Console ". This method can be recommended as an additional method ofprotection against myocardial ischemia-reperfusion injury.