Chronic continuous normobaric hypoxia (CNH) increases cardiac tolerance to ischemia/reperfusion injury in vivo and this effect is mediated via µ and delta2 opioid receptors (ORs) activation. CNH has also been shown to be cardioprotective in isolated rat heart. In this study, we hypothesize that this cardioprotective effect of CNH is mediated by activation of µ and delta2 ORs and preservation of mitochondrial function. Hearts from rats adapted to CNH (12 % oxygen) for 3 weeks were extracted, perfused in the Langendorff mode and subjected to 45 min of global ischemia and 30 min of reperfusion. Intervention groups were pretreated for 10 min with antagonists for different OR types: naloxone (300 nmol/l), the selective delta OR antagonist TIPP(psi) (30 nmol/l), the selective delta1 OR antagonist BNTX (1 nmol/l), the selective delta2 OR antagonist naltriben (1 nmol/l), the selective peptide µ OR antagonist CTAP (100 nmol/l) and the selective delta OR antagonist nor-binaltorphimine (3 nmol/l). Creatine kinase activity in coronary effluent and cardiac contractile function were monitored to assess cardiac injury and functional impairment. Additionally, cardiac tissue was collected to measure ATP and to isolate mitochondria to measure respiration rate and calcium retention capacity. Adaptation to CNH decreased myocardial creatine kinase release during reperfusion and improved the postischemic recovery of contractile function. Additionally, CNH improved mitochondrial state 3 and uncoupled respiration rates, ADP/O, mitochondrial transmembrane potential and calcium retention capacity and myocardial ATP level during reperfusion compared to the normoxic group. These protective effects were completely abolished by naloxone, TIPP(psi), naltriben, CTAP but not BNTX or nor-binaltorphimine. These results suggest that cardioprotection associated with adaptation to CNH is mediated by µ and delta2 opioid receptors activation and preservation of mitochondrial function.

• MeSH
• hypoxie patofyziologie   MeSH
• krysa rodu rattus MeSH
• narkotika - antagonisté farmakologie   MeSH
• orgánové kultury - kultivační techniky MeSH
• potkani Wistar MeSH
• receptory opiátové delta antagonisté a inhibitory   fyziologie   MeSH
• receptory opiátové mu antagonisté a inhibitory   fyziologie   MeSH
• reperfuzní poškození myokardu patofyziologie   prevence a kontrola   MeSH
• srdeční mitochondrie účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Cardiac sensitivity to oxygen deprivation changes significantly during ontogenetic development. However, the mechanisms for the higher tolerance of the immature heart, possibilities of protection, and the potential impact of perinatal hypoxia on cardiac tolerance to oxygen deprivation in adults have not yet been satisfactorily clarified. The hypoxic tolerance of an isolated rat heart showed a triphasic pattern: significant decrease from postnatal day 1 to 7, followed by increase to the weaning period, and final decline to adulthood. We have observed significant ontogenetic changes in mitochondrial oxidative phosphorylation and mitochondrial membrane potential, as well as in the role of the mitochondrial permeability transition pores in myocardial injury. These results support the hypothesis that cardiac mitochondria are deeply involved in the regulation of cardiac tolerance to oxygen deprivation during ontogenetic development. Ischemic preconditioning failed to increase tolerance to oxygen deprivation in the highly tolerant hearts of newborn rats. Chronic hypoxic exposure during early development may cause in-utero or neonatal programming of several genes that can change the susceptibility of the adult heart to ischemia-reperfusion injury; this effect is sex dependent. These results would have important clinical implications, since cardiac sensitivity in adult patients may be significantly affected by perinatal hypoxia in a sex-dependent manner.

• MeSH
• hypoxie buňky MeSH
• hypoxie embryologie   metabolismus   MeSH
• ischemická choroba srdeční embryologie   etiologie   metabolismus   MeSH
• kardiovaskulární komplikace v těhotenství metabolismus   MeSH
• lidé MeSH
• myokard metabolismus   MeSH
• reperfuzní poškození myokardu etiologie   metabolismus   MeSH
• srdce embryologie   růst a vývoj   MeSH
• srdeční mitochondrie metabolismus   MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Epoxyeicosatrienoic acids (EETs) decrease cardiac ischemia-reperfusion injury; however, the mechanism of their protective effect remains elusive. Here, we investigated the cardioprotective action of a novel EET analog, EET-B, in reperfusion and the role of hypoxia-inducible factor (HIF)-1α in such action of EET-B. Adult male rats were subjected to 30 min of left coronary artery occlusion followed by 2 h of reperfusion. Administration of 14,15-EET (2.5 mg/kg) or EET-B (2.5 mg/kg) 5 min before reperfusion reduced infarct size expressed as a percentage of the area at risk from 64.3 ± 1.3% in control to 42.6 ± 1.9% and 46.0 ± 1.6%, respectively, and their coadministration did not provide any stronger effect. The 14,15-EET antagonist 14,15-epoxyeicosa-5( Z)-enoic acid (2.5 mg/kg) inhibited the infarct size-limiting effect of EET-B (62.5 ± 1.1%). Similarly, the HIF-1α inhibitors 2-methoxyestradiol (2.5 mg/kg) and acriflavine (2 mg/kg) completely abolished the cardioprotective effect of EET-B. In a separate set of experiments, the immunoreactivity of HIF-1α and its degrading enzyme prolyl hydroxylase domain protein 3 (PHD3) were analyzed in the ischemic areas and nonischemic septa. At the end of ischemia, the HIF-1α immunogenic signal markedly increased in the ischemic area compared with the septum (10.31 ± 0.78% vs. 0.34 ± 0.08%). After 20 min and 2 h of reperfusion, HIF-1α immunoreactivity decreased to 2.40 ± 0.48% and 1.85 ± 0.43%, respectively, in the controls. EET-B blunted the decrease of HIF-1α immunoreactivity (7.80 ± 0.69% and 6.44 ± 1.37%, respectively) and significantly reduced PHD3 immunogenic signal in ischemic tissue after reperfusion. In conclusion, EET-B provides an infarct size-limiting effect at reperfusion that is mediated by HIF-1α and downregulation of its degrading enzyme PHD3. NEW & NOTEWORTHY The present study shows that EET-B is an effective agonistic 14,15-epoxyeicosatrienoic acid analog, and its administration before reperfusion markedly reduced myocardial infarction in rats. Most importantly, we demonstrate that increased hypoxia-inducible factor-1α levels play a role in cardioprotection mediated by EET-B in reperfusion likely by mechanisms including downregulation of the hypoxia-inducible factor -1α-degrading enzyme prolyl hydroxylase domain protein 3.

• MeSH
• down regulace MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa genetika   metabolismus   MeSH
• funkce levé komory srdeční účinky léků   MeSH
• infarkt myokardu enzymologie   patologie   patofyziologie   prevence a kontrola   MeSH
• kyselina 8,11,14-eikosatrienová analogy a deriváty   farmakologie   MeSH
• modely nemocí na zvířatech MeSH
• myokard enzymologie   patologie   MeSH
• potkani Sprague-Dawley MeSH
• prolyl-4-hydroxylasy HIF genetika   metabolismus   MeSH
• proteolýza MeSH
• remodelace komor účinky léků   MeSH
• reperfuzní poškození myokardu enzymologie   patologie   patofyziologie   prevence a kontrola   MeSH
• signální transdukce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

• MeSH
• ischemie mozku patofyziologie   MeSH
• lidé MeSH
• mozková hypoxie * patofyziologie   MeSH
• peroxidace lipidů fyziologie   MeSH
• reperfuzní poškození enzymologie   metabolismus   MeSH
• vápník škodlivé účinky   MeSH
• volné radikály terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• abstrakty MeSH
• práce podpořená grantem MeSH

• MeSH
• asfyxie novorozenců etiologie   MeSH
• dítě MeSH
• hypotermie * MeSH
• kojenec MeSH
• lidé MeSH
• management nemoci MeSH
• mozková hypoxie a ischemie * diagnóza   etiologie   prevence a kontrola   MeSH
• nemoci nedonošenců MeSH
• nemoci novorozenců etiologie   MeSH
• novorozenec MeSH
• reperfuzní poškození metabolismus   patologie   MeSH
• směrnice pro lékařskou praxi jako téma MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH

(Pro)renin receptor (PRR) contributes to regulating many physiological and pathological processes; however, the role of PRR-mediated signaling pathways in myocardial ischemia/reperfusion injury (IRI) remains unclear. In this study, we used an in vitro model of hypoxia/reoxygenation (H/R) to mimic IRI and carried out PRR knockdown by siRNA and PRR overexpression using cDNA in H9c2 cells. Cell proliferation activity was examined by MTT and Cell Counting Kit-8 (CCK-8) assays. Apoptosis-related factors, autophagy markers and beta-catenin pathway activity were assessed by real-time PCR and western blotting. After 24 h of hypoxia followed by 2 h of reoxygenation, the expression levels of PRR, LC3B-I/II, Beclin1, cleaved caspase-3, cleaved caspase-9 and Bax were upregulated, suggesting that apoptosis and autophagy were increased in H9c2 cells. Contrary to the effects of PRR downregulation, the overexpression of PRR inhibited proliferation, induced apoptosis, increased the expression of pro-apoptotic factors and autophagy markers, and promoted activation of the beta-catenin pathway. Furthermore, all these effects were reversed by treatment with the beta-catenin antagonist DKK-1. Thus, we concluded that PRR activation can trigger H/R-induced apoptosis and autophagy in H9c2 cells through the beta-catenin signaling pathway, which may provide new therapeutic targets for the prevention and treatment of myocardial IRI.

• MeSH
• apoptóza fyziologie   MeSH
• autofagie fyziologie   MeSH
• beta-katenin metabolismus   MeSH
• buněčné linie MeSH
• hypoxie buňky fyziologie   MeSH
• kardiomyocyty metabolismus   patologie   MeSH
• krysa rodu rattus MeSH
• kyslík metabolismus   MeSH
• receptory buněčného povrchu metabolismus   MeSH
• reperfuzní poškození myokardu metabolismus   patologie   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• asfyxie novorozenců etiologie   MeSH
• dítě MeSH
• hypotermie * MeSH
• informovaný souhlas u nezletilých normy   zákonodárství a právo   MeSH
• kojenec MeSH
• lidé MeSH
• management nemoci MeSH
• mozková hypoxie a ischemie * diagnóza   etiologie   prevence a kontrola   MeSH
• nemoci nedonošenců MeSH
• nemoci novorozenců etiologie   MeSH
• novorozenec MeSH
• reperfuzní poškození metabolismus   patologie   MeSH
• směrnice pro lékařskou praxi jako téma MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH

Adaptation to chronic hypoxia represents a potential cardioprotective intervention reducing the extent of acute ischemia/reperfusion (I/R) injury, which is a major cause of death worldwide. The main objective of this study was to investigate the anti-apoptotic Akt/hexokinase 2 (HK2) pathway in hypoxic hearts subjected to I/R insult. Hearts isolated from male Wistar rats exposed either to continuous normobaric hypoxia (CNH; 10% O2) or to room air for 3 weeks were perfused according to Langendorff and subjected to 10 min of no-flow ischemia and 10 min of reperfusion. The hearts were collected either after ischemia or after reperfusion and used for protein analyses and quantitative fluorescence microscopy. The CNH resulted in increased levels of HK1 and HK2 proteins and the total HK activity after ischemia compared to corresponding normoxic group. Similarly, CNH hearts exhibited increased ischemic level of Akt protein phosphorylated on Ser473. The CNH also strengthened the interaction of HK2 with mitochondria and prevented downregulation of mitochondrial creatine kinase after reperfusion. The Bax/Bcl-2 ratio was significantly lower after I/R in CNH hearts than in normoxic ones, suggesting a lower probability of apoptosis. In conclusion, the Akt/HK2 pathway is likely to play a role in the development of a cardioprotective phenotype of CNH by preventing the detachment of HK2 from mitochondria at reperfusion period and decreases the Bax/Bcl-2 ratio during I/R insult, thereby lowering the probability of apoptosis activation in the mitochondrial compartment.

• MeSH
• hexokinasa metabolismus   MeSH
• krysa rodu rattus MeSH
• myokard enzymologie   patologie   MeSH
• potkani Wistar MeSH
• protoonkogenní proteiny c-akt metabolismus   MeSH
• reperfuzní poškození myokardu enzymologie   patologie   MeSH
• srdeční mitochondrie enzymologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• dietní tuky metabolismus   MeSH
• hypoxie buňky MeSH
• ischemická choroba srdeční prevence a kontrola   MeSH
• ischemické přivykání MeSH
• modely nemocí na zvířatech MeSH
• reperfuzní poškození myokardu metabolismus   prevence a kontrola   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• antagonisté excitačních aminokyselin terapeutické užití   MeSH
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mozková hypoxie a ischemie etiologie   farmakoterapie   patofyziologie   MeSH
• nemoci nedonošenců MeSH
• neuroprotektivní látky terapeutické užití   MeSH
• novorozenec MeSH
• reperfuzní poškození metabolismus   patologie   MeSH
• scavengery volných radikálů terapeutické užití   MeSH
• zánět MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH