We report the influence of aging on multiple markers of oxidative-nitrosative stress in the heart of adult (6-month), aged (30-month) and very aged (36-month) Fischer 344/NNiaHSd x Brown Norway/BiNia (F344/NXBN) rats. Compared to adult (6-month) hearts, indices of oxidative (superoxide anion [O2*-], 4-hydroxy-2-nonenal [4-HNE]) and nitrosative (protein nitrotyrosylation) stress were 34.1 +/- 28.1%, 186 +/- 28.1% and 94 +/- 5.8% higher, respectively, in 36-month hearts and these findings were highly correlated with increases in left ventricular wall thickness (r > 0.669; r > 0.710 and P
Laboratory of Experimental Cardiology, Institute of Cardiology, Tomsk Scientific Center, Siberian Division, Russian Academy of Medical Sciences, ul. Shevchenko 24, Tomsk, 634050 Russia.
It has been found that in vivo pretreatment of rats with the sigma receptor antagonist DuP 734 (1 mg/kg) resulted in an increase in the heart tolerance to ischemic and reperfusion arrhythmias both in vivo and ex vivo. Administration of DuP 734 (1 mg/liter) directly in the perfusion solution of isolated rat heart 10 min before total ischemia also promoted a decrease in the incidence of reperfusion arrhythmias. The normoxic perfusion of isolated rat heart at a dose of 1 mg/liter had no effect on the action potential. It was concluded that antiarrhythmic effect of DuP 734 might depend on the decrease in the Ca2+ overload but not on K+ and Na+ channel blockade.
The changes of functional state isolated by Lanhendorf old rat hearts with low content of ubiqinone--coenzyme Q (CoQ) under activation of it endogenous synthesis through administration of precursors--4-hydroxybenzoic acid, methionine and modulator vitamin E were studied. The activation of ubiqinone biosynthesis contribute to cardioprotective effect due to reduce the degree of the ischemia-reperfusion injury in old rat heart, namely the restoration of myocardial contractile function and coronary flow as well as decrease the end diastolic pressure and oxygen cost of the heart compared with control group of the animals during ischemia-reperfusion. Thus the results allow to conclude that the activation of KoQ biosynthesis under administration of it precursors has protective effect in the development of the heart postreperfusion damages in aging.
In experiments on anaesthetized dogs with modeling of experimental ischemia (90 min) and reperfusion (180 min) the cardioprotective influence of the preischemic activation of ATP-sensitive potassium (K(ATP)) channels by intravenous introduction of flokalin, a new fluorine-containing opener of these channels was shown. Flokalin was introduced in dose 0.1 mg/kg of animal body weight which practically did not change the parameters of hemodynamic in conditions of normoxia. Thus, the experiments performed about flokalin influence on changes of cardiohemodynamic during ischemia-reperfusion of myocardium showed certain features of ischemia-reperfusion syndrome development under conditions of K(ATP) channels activity stimulation. In our opinion, positive influence offlokalin can be explained by moderate decrease of blood pressure that decreases loading of the damaged heart and allows to preserve cardiac emission in the first period of ischemia. Also, these positive effects can be explained by prevention of the increase of coronal vessel resistance and relative preservation of myocardium contractility indexes by flokalin in the period of reperfusion. All protective properties of flokalin showed above result in diminishing of infarct size of myocardium after ischemia-reperfusion on 37% versus control experiments.
The rhythmoinotropic dependence of the papillary muscles was studied in rats with postinfarction cardiosclerosis after blocking of beta(1)-adrenoreceptors by concor (7 mg/kg daily). The development of postinfarction cardiosclerosis led to a reduction of the postextrasystolic potentiation and of potentiation induced by periods of rest. Preliminary blocking of beta(1)-adrenoreceptors stimulated the postextrasystolic contractions and contractions after periods of rest in the myocardium of rats with postinfarction cardiosclerosis. These results suggest that blocking of beta(1)-adrenoreceptors promotes an improvement of calcium-accumulating function of the cardiomyocyte sarcoplasmatic reticulum in the myocardium of rats with postinfarction cardiosclerosis.
Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Biotechnology Research & Training Center, Indianapolis, IN 46202, USA.
The aging heart undergoes well characterized structural changes associated with functional decline, though the underlying mechanisms are not understood. The aim of this study was to determine to what extent ventricular myocardial protein expression was altered with age and which proteins underwent protein nitration. Fischer 344 x Brown Norway F1 hybrid (FBN) rats of four age groups were used, 4, 12, 24, and 34 months. Differential protein expression was determined by 2-DE and proteins were identified by peptide mass fingerprinting. Altered protein nitration with age was assessed by immunoblotting. Over 1000 protein spots per sample were detected, and 255 were found to be differentially expressed when all aged groups were compared to young rats (4 months) (p0.05). A strong positive correlation between differential protein expression and increasing age (p=0.03, R(2)=0.997) indicated a progressive, rather than abrupt, change with age. Of 46 differentially expressed proteins identified, seventeen have roles in apoptosis, ten in hypertrophy, seven in fibrosis, and three in diastolic dysfunction, aging-associated processes previously reported in both human and FBN rat heart. Protein expression alterations detected here could have beneficial effects on cardiac function; thus, our data indicate a largely adaptive change in protein expression during aging. In contrast, differential protein nitration increased abruptly, rather than progressively, at 24 months of age. Altogether, the results suggest that differential myocardial protein expression occurs in a progressive manner during aging, and that a proteomic-based approach is an effective method for the identification of potential therapeutic targets to mitigate aging-related myocardial dysfunction.
Laboratory of Experimental Cardiology, Institute of Cardiology, Tomsk Research Center, Siberian Division of the Russian Academy of Medical Sciences, Russia.
Preliminary intravenous injection of peptide agonist of delta1-opioid receptors DPDPE (0.5 mg/kg) decreased the incidence of occlusion (10 min) and reperfusion (10 min) arrhythmias in rats. By contrast, delta2-opioid receptor agonist DSLET produced no effect on the incidence of arrhythmias provoked by coronary occlusion and reperfusion. Preliminary injection of selective delta-receptor antagonist ICI 174,864 (2.5 mg/kg) or TIPP[y] (0.5 mg/kg) completely abolished the antiarrhythmic effect of DPDPE. Stimulation of cardiac delta1-opioid receptors with DPDPE added to perfusion saline in concentrations of 0.1 and 0.5 mg/liter decreased the incidence of reperfusion arrhythmias. Addition of DPDPE to perfusion saline in a concentration of 0.1 mg/liter prevented reoxygenation destruction of cardiomyocytes. By contrast, no cardioprotective effect of this peptide was observed at a concentration of 0.5 mg/liter in perfusion saline or when it was injected intravenously. It is concluded that the cardioprotective and antiarrhythmic effects of DPDPE are caused by activation of cardiac delta1-opioid receptors.
Effect of ischemic postconditioning on infarct size in patients with ST-elevation myocardial infarction treated by primary PCI results of the POSTEMI (POstconditioning in ST-Elevation Myocardial Infarction) randomized trial.
Reduction of infarct size by ischemic postconditioning (IPost) has been reported in smaller proof-of-concept clinical studies, but has not been confirmed in other smaller studies. The principle needs to be evaluated in larger groups of ST-elevation myocardial infarction (STEMI) patients before being implemented in clinical practice. This study assessed the effect of ischemic postcoditioning (IPost) on infarct size in patients with STEMI treated by primary percutaneous coronary intervention (PCI).
Patients with first-time STEMI,
Notes
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