Remifentanil but not sufentanil induces cardioprotection in human ischemic heart muscle in vitro.

BACKGROUND: Previous studies on animal models have suggested that δ-opioid receptor (OR) signaling is the primary pathway responsible for opioids' cardioprotective effect. We hypothesize that the µ-OR's activation protects the human heart muscle. METHODS: We performed the experiments on muscular trabeculae obtained from the right atrial appendages of 104 consecutive patients subjected to coronary artery bypass surgery. Two trabeculae from each patient were studied simultaneously and exposed to 60 min of hypoxia with subsequent 60 min of reoxygenation. Remifentanil (5 µM or 50 µM) or sufentanil (40 µM or 400 µM) was used from the time of reoxygenation. Trabeculae contractility was assessed as the maximal amplitude of the contraction at baseline, after 60 min of hypoxia, during reoxygenation, and after norepinephrine application. RESULTS: During reperfusion, the application of remifentanil improved cardiomyocytes' function as compared to the control group (time from reperfusion: 15 min: 39.8% vs. 21.7%, p = 0.01; 30 min: 41.4% vs. 21.8%, p = 0.01; 60 min: 42.7% vs. 26.9%, p = 0.04; after norepinephrine: 64.7% vs. 43.2%, p = 0.03). The application of sufentanil did not influence cardiomyocyte function as can be seen when comparing the results of the experimental and control group. CONCLUSIONS: Remifentanil, but not sufentanil, induces a cardioprotective effect on human right atria muscle in in vitro conditions, manifested as the increased amplitude of their contraction during reperfusion after 60 min of ischemia.

Opioidergic conditioning of the human heart muscle in nitric oxide-dependent mechanism.

BACKGROUND: Opioidergic conditioning is well documented to trigger cardioprotection against ischemia/ reperfusion (I/R) injury. Previous studies on animal models have suggested that nitric oxide (NO) mediates the beneficial effect of opioids, but the role of NO in humans seems to be controversial. OBJECTIVES: The aim of the study was to assess the influence of NO modulators on opioid-induced cardioprotection in the human myocardium. MATERIAL AND METHODS: Trabeculae of the human right atria were electrically driven in an organ bath and subjected to simulated I/R injury. The non-selective inhibitor of nitric oxide synthase (NOS) - N-methyl-l-arginine (LNMMA), the donor of NO - S-Nitroso-N-acetylpenicillamine (SNAP) or morphine (in the amount of 10-4 M) were used at the time of re-oxygenation. The additional trabecula was subjected to the hypoxia protocol only (control). The contractility of the myocardium was assessed as the maximal force of a contraction (Amax), the rate of rise of the force of a contraction (Slope L) and the cardiac muscle relaxation - as the rate of decay of the force of a contraction (Slope T). RESULTS: The application of 100 µM LNMMA resulted in the decrease of Amax, Slope L and Slope T during the re-oxygenation period as compared to control. The application of 10-4 M morphine and/or 100 µM SNAP resulted in a partial reversal of the detrimental influence of LNMMA. CONCLUSIONS: At the re-oxygenation period, the blockade of NO synthesis has a deleterious effect on the systolic and diastolic function of the human myocardium as well as attenuates the beneficial effect of morphine conditioning.

Ischemic conditioning of human heart muscle depends on opioid-receptor system.

BACKGROUND: Despite progress in the invasive treatment of ischemic heart disease, the ability to limit ischemia-reperfusion (I/R) injury remains largely unrealized. Ischemic pre-conditioning (IPC) and post-conditioning (POC) induce the protective mechanisms of resistance against I/R injury. Stimulation of opioid receptors mimic the protective effect of IPC or POC in an animal models. We tested the hypothesis, that IPC and POC provide cardioprotection in opioid-dependent mechanism in human myocardium. METHODS: Human atrial trabeculae were subjected to I/R injury. To achieve IPC, single hypoxia period preceded the applied lethal hypoxia, to achieve POC triple hypoxia periods followed lethal hypoxia. Naloxone was used at the onset of lethal hypoxia in IPC protocol, and at the time of re-oxygenation in POC protocol. Contractive function of the myocardium was assessed as maximal force of contraction (Amax), rate of rise of force of contraction (+dV/dT) and diastolic parameter - rate of decay of force of contraction (-dV/dT). RESULTS: Co-application of naloxone with IPC or POC resulted in decrease of Amax, +dV/dT and -dV/dT during re-oxygenation period as compared to IPC or POC only. CONCLUSIONS: Naloxone abrogates beneficial effect of IPC and POC. IPC and POC in humans provide cardioprotection in opioid receptor system dependent mechanism.

Effects of endogenous cardioprotective mechanisms on ischemia-reperfusion injury.

Ischemic heart disease have been remarked as a leading cause of morbidity and mortality in adults. Early restoration of cardiac perfusion is necessary to restore perfusion of ischemic heart muscle. Effective revascularization reduce mortality by limiting myocardial necrosis at the acute phase of the cardiac infarction. However, reperfusion may induce a cascade of pathophysiological reactions causing the increase of the infarct area of the myocardium This phenomenon known as ischemia-reperfusion injury is responsible for up to 50% of the final infarct size. Sequences of brief episodes of nonlethal ischemia and reperfusion applied before (preconditioning - IPC) or after (postconditioning - POC) the coronary occlusion are well documented to reduce the ischemiareperfusion injury. These phenomena improve cardiac function by mobilizing the molecular and cellular mechanisms limiting reperfusion injury. The mechanisms underlying IPC or POC are still not clarified, but strong experimental evidence suggests that opioids may be the part of the endogenous cardioprotective response to I/R injury. Stimulation of opioid receptors activates related to POC mechanisms affecting protection to the ischemic myocardium, while the use of non-selective opioid receptor antagonist - naloxone reduces this effect. There is no consensus that the subtype of opioid receptor is responsible for the protection of the human heart muscle. Morphine may reduce cardiac preload by peripheral vasodilatation. Numerous studies show a direct cardioprotective effect of the opioid pathway in ischemic conditions. Opioids act via membrane receptors: µ, δ, κ. The predominant subtype in the human cardiac cells are µ- and δ - opioid receptors. It has been hypothetized that opioid receptor activation exerts cardioprotection in human heart muscle pathway what may give insight into the explanation of the protective mechanisms in the acute myocardial infarction.

'Opioidergic postconditioning' of heart muscle during ischemia/reperfusion injury.

BACKGROUND: Ischemic preconditioning and postconditioning are the novel strategies of attaining cardioprotection against ischemia/reperfusion (I/R) injury. Previous studies suggested the role of opioid pathway, however the class of opioid receptors responsible for this effect in humans remains unknown. The aim of the study was to assess the influence of opioids on simulated I/R injury outcomes in the hu-man myocardium. METHODS: Trabeculae of the human right atrium were electrically driven in organ bath and subjected to simulated I/R injury. Morphine (10-4M, 10-5M, 10-6M) or d-opioid receptor agonist DADLE (10-8M, 10-7M, 10-6M) was used at the time of re-oxygenation. Additional trabecula was subjected to hypoxia protocol only (Control). Contractive force of the myocardium was assessed as the maximal force of a contraction (Amax), the rate of rise of the force of a contraction (Slope L) and relaxation as the rate of decay of the force of a contraction (Slope T). RESULTS: Application of morphine 10-4M resulted in increase of Amax, Slope L and Slope T during re-oxygenation period as compared to Control (77.99 ± 1.5% vs. 68.8 ± 2.2%, p < 0.05; 45.72 ± 2.9% vs. 34.12 ± 5.1%, p < 0.05; 40.95 ± 2.5% vs. 32.37 ± 4.3%, p < 0.05). Parameters were not significantly different in the lower morphine concentrations. Application of DADLE 10-6M resulted in decrease of Amax and Slope L as compared to Control (68.13 ± 5.5% vs. 76.62 ± 6.6%, p < 0.05; 28.29 ± 2.2 vs. 34.80 ± 3.9%, p < 0.05). CONCLUSIONS: At re-oxygenation, morphine improves systolic and diastolic function of the human myo-cardium in the dose-dependent manner. Delta-opioid receptor stimulation attenuates systolic function of human heart muscle which remains in contrast to previous reports with animal models of I/R injury. (Cardiol J 2017; 24, 4: 419-425).

The co-application of hypoxic preconditioning and postconditioning abolishes their own protective effect on systolic function in human myocardium.

BACKGROUND: Ischemic preconditioning (IPC) and postconditioning (POC) are well documented to trigger cardioprotection against ischemia/reperfusion (I/R) injury, but the effect oftheir both co-application remains unclear in human heart. The present study sought to assessthe co-application of IPC and POC on fragments of human myocardium in vitro. METHODS: Muscular trabeculae of the human right atrial were electrically driven in the organbath and subjected to simulated I/R injury - hypoxia/re-oxygenation injury in vitro. To achieveIPC of trabeculae the single brief hypoxia period preceded the applied lethal hypoxia, and to achieve POC triple brief hypoxia periods followed the lethal hypoxia. Additional muscular trabeculae were exposed only to the hypoxic stimulation (Control) or were subjected to the non-hypoxic stimulation (Sham). 10 µM norepinephrine (NE) application ended every experiment to assess viability of trabeculae. The contraction force of the myocardium assessed as a maximal amplitude of systolic peak (%Amax) was obtained during the whole experiment's period. RESULTS: Co-application of IPC and POC resulted in decrease in %Amax during the re-oxygentaionperiod and after NE application, as compared to Control (30.35 ± 2.25 vs. 41.89 ± 2.25, 56.26 ± 7.73 vs. 65.98 ± 5.39, respectively). This was in contrary to the effects observed when IPC and POC were applied separately. CONCLUSIONS: The co-application of IPC and POC abolishes the cardioprotection of either intervention alone against simulated I/R injury in fragments of the human right heart atria.

Effects of pantoprazole on dual antiplatelet therapy in stable angina pectoris patients after percutaneous coronary intervention.

BACKGROUND: Our aim was to prospectively assess the potential influence of pantoprazole therapy on the antiplatelet effects of acetylsalicylic acid (ASA) and clopidogrel (CLO) in stable angina pectoris (SAP) patients after percutaneous coronary intervention (PCI). METHODS: Forty-four patients with SAP (CCS I-III) and successful PCI with stent implantation were enrolled into the study. The patients were divided into group proton pump inhibitors (PPI): 23 patients with indications for PPI (F/M = 9/14; age = 64 ± 9; standard therapy + 20 mg pantoprazole) and the control group (group C): 21 patients (F/M = 6/15; age = 64 ± 8; standard therapy). The platelet function analysis in whole blood based on impedance aggregometry (ASPI, COL, ADP, TRAP tests) using Multiplate--V2.02.11 was performed 18-24 h after the PCI + CLO loading dose (600 mg) and 30 days after PCI. RESULTS: Both baseline patient characteristics and clinical outcomes were comparable between the study groups. There were no differences in the mean values of the platelets (PTL) tests measured at the 30(th) day after PCI between both groups (PPI vs. C: ASPI: 24.6 ± 10.0 vs. 42.1 ± 14.8 U, COL: 32.9 ± 8.6 vs. 34.0 ± 7.7 U, ADP: 26.8 ± 12.4 vs. 30.4 ± 8.1 U, TRAP: 78.7 ± 16.6 vs. 78.1 ± 22.6 U, p = ns). The mean delta values of the PTL tests (18-24 h post-PCI/30 days post-PCI) were also comparable between the groups. The PTL aggregometry results were related to time (ADP, ASPI, TRAP vs. time, p = 0.001; COL vs. time, p = 0.03)--the baseline values of ADP, ASPI, COL and TRAP tests were smaller than those measured after the one-month observation. CONCLUSION: Pantoprazole treatment does not impair the efficacy of dual antiplatelet therapy in patients with SAP after PCI.