Delayed reperfusion of the ischemic heart (I/R) is known to impair the recovery of cardiac function and produce a wide variety of myocardial defects, including ultrastructural damage, metabolic alterations, subcellular Ca2+-handling abnormalities, activation of proteases, and changes in cardiac gene expression. Although I/R injury has been reported to induce the formation of reactive oxygen species (ROS), inflammation, and intracellular Ca2+ overload, the generation of oxidative stress is considered to play a critical role in the development of cardiac dysfunction. Increases in the production of superoxide, hydroxyl radicals, and oxidants, such as hydrogen peroxide and hypochlorous acid, occur in hearts subjected to I/R injury. In fact, mitochondria are a major source of the excessive production of ROS in I/R hearts due to impairment in the electron transport system as well as activation of xanthine oxidase and NADPH oxidase. Nitric oxide synthase, mainly present in the endothelium, is also activated due to I/R injury, leading to the production of nitric oxide, which, upon combination with superoxide radicals, generates nitrosative stress. Alterations in cardiac function, sarcolemma, sarcoplasmic reticulum Ca2+-handling activities, mitochondrial oxidative phosphorylation, and protease activation due to I/R injury are simulated upon exposing the heart to the oxyradical-generating system (xanthine plus xanthine oxidase) or H2O2. On the other hand, the activation of endogenous antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, and the concentration of a transcription factor (Nrf2), which modulates the expression of various endogenous antioxidants, is depressed due to I/R injury in hearts. Furthermore, pretreatment of hearts with antioxidants such as catalase plus superoxide dismutase, N-acetylcysteine, and mercaptopropionylglycerine has been observed to attenuate I/R-induced subcellular Ca2+ handling and changes in Ca2+-regulatory activities; additionally, it has been found to depress protease activation and improve the recovery of cardiac function. These observations indicate that oxidative stress is intimately involved in the pathological effects of I/R injury and different antioxidants attenuate I/R-induced subcellular alterations and improve the recovery of cardiac function. Thus, we are faced with the task of developing safe and effective antioxidants as well as agents for upregulating the expression of endogenous antioxidants for the therapy of I/R injury.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

An excessive increase in reactive oxygen species (ROS) levels is one of the main causes of mitochondrial dysfunction. However, when ROS levels are maintained in balance with antioxidant mechanisms, ROS fulfill the role of signaling molecules and modulate various physiological processes. Recent advances in mitochondrial bioenergetics research have revealed a significant interplay between mitochondrial peroxiredoxins (PRDXs) and monoamine oxidase-A (MAO-A) in regulating ROS levels. Both proteins are associated with hydrogen peroxide (H2O2), MAO-A as a producer and PRDXs as the primary antioxidant scavengers of H2O2. This review focuses on the currently available knowledge on the function of these proteins and their interaction, highlighting their importance in regulating oxidative damage, apoptosis, and metabolic adaptation in the heart. PRDXs not only scavenge excess H2O2, but also act as regulatory proteins, play an active role in redox signaling, and maintain mitochondrial membrane integrity. Overexpression of MAO-A is associated with increased oxidative damage, leading to mitochondrial dysfunction and subsequent progression of cardiovascular diseases (CVD), including ischemia/reperfusion injury and heart failure. Considering the central role of oxidative damage in the pathogenesis of many CVD, targeting PRDXs activation and MAO-A inhibition may offer new therapeutic strategies aimed at improving cardiac function under conditions of pathological load related to oxidative damage. Keywords: Mitochondria, Peroxiredoxin, Monoamine oxidase-A, Reactive oxygen species, Cardioprotective signaling.

• MeSH
• lidé MeSH
• monoaminoxidasa * metabolismus   MeSH
• oxidační stres MeSH
• peroxiredoxiny * metabolismus   MeSH
• reaktivní formy kyslíku * metabolismus   MeSH
• signální transdukce * MeSH
• srdeční mitochondrie metabolismus   enzymologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Extracellular potassium concentration might modify electrophysiological properties in the border zone of ischemic myocardium. We evaluated the depolarization and repolarization characteristics across the ischemic-normal border under [K+] variation. Sixty-four-lead epicardial mapping was performed in 26 rats ([K+] 2.3-6.4 mM) in a model of acute ischemia/reperfusion. The animals with [K+] < 4.7 mM (low-normal potassium) had an ischemic zone with ST-segment elevation and activation delay, a border zone with ST-segment elevation and no activation delay, and a normal zone without electrophysiological abnormalities. The animals with [K+] >4.7 mM (normal-high potassium) had only the ischemic and normal zones and no transitional area. Activation-repolarization intervals and local conduction velocities were inversely associated with [K+] in linear regression analysis with adjustment for the zone of myocardium. The reperfusion extrasystolic burden (ESB) was greater in the low-normal as compared to normal-high potassium animals. Ventricular tachycardia/fibrillation incidence did not differ between the groups. In patch-clamp experiments, hypoxia shortened action potential duration at 5.4 mM but not at 1.3 mM of [K+]. IK(ATP) current was lower at 1.3 mM than at 5.4 mM of [K+]. We conclude that the border zone formation in low-normal [K+] was associated with attenuation of IK(ATP) response to hypoxia and increased reperfusion ESB.

• MeSH
• akční potenciály * fyziologie   MeSH
• draslík * krev   metabolismus   MeSH
• ischemická choroba srdeční * patofyziologie   krev   metabolismus   MeSH
• krysa rodu rattus MeSH
• potkani Wistar MeSH
• reperfuzní poškození myokardu krev   patofyziologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Experimental and clinical studies have clearly demonstrated significant sex differences in myocardial structure and function, both under physiological and pathological conditions. The best example are significant sex differences in the cardiac tolerance to ischemia/reperfusion injury: pre-menopausal adult female hearts are more resistant as compared to the male myocardium. The importance of these findings is supported by the fact that the number of studies dealing with this issue increased significantly in recent years. Detailed molecular and cellular mechanisms responsible for sex differences are yet to be elucidated; however, it has been stressed that the differences cannot be explained only by the effect of estrogens. In recent years, a promising new hypothesis has been developed, suggesting that mitochondria may play a significant role in the sex differences in cardiac tolerance to oxygen deprivation. However, one is clear already today: sex differences are so important that they should be taken into consideration in the clinical practice for the selection of the optimal diagnostic and therapeutic strategy in the treatment of ischemic heart disease. The present review attempts to summarize the progress in cardiovascular research on sex-related differences in cardiac tolerance to oxygen deprivation during the last 40 years, i.e. from the first experimental observation. Particular attention was paid to the sex-related differences of the normal heart, sex-dependent tolerance to ischemia-reperfusion injury, the role of hormones and, finally, to the possible role of cardiac mitochondria in the mechanism of sex-dependent differences in cardiac tolerance to ischemia/reperfusion injury. Key words: Female heart, Cardiac hypoxic tolerance, Ischemia-reperfusion injury, Sex differences.

• MeSH
• kyslík metabolismus   MeSH
• lidé MeSH
• myokard metabolismus   patologie   MeSH
• pohlavní dimorfismus * MeSH
• reperfuzní poškození myokardu metabolismus   patofyziologie   MeSH
• sexuální faktory MeSH
• srdeční mitochondrie metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The aim of the study was to examine the potential role of mitochondrial permeability transition pore (mPTP) in the cardioprotective effect of chronic continuous hypoxia (CH) against acute myocardial ischemia/reperfusion (I/R) injury. Adult male Wistar rats were adapted to CH for 3 weeks, while their controls were kept under normoxic conditions. Subsequently, they were subjected to I/R insult while being administered with mPTP inhibitor, cyclosporin A (CsA). Infarct size and incidence of ischemic and reperfusion arrhythmias were determined. Our results showed that adaptation to CH as well as CsA administration reduced myocardial infarct size in comparison to the corresponding control groups. However, administration of CsA did not amplify the beneficial effect of CH, suggesting that inhibition of mPTP opening contributes to the protective character of CH.

• MeSH
• chronická nemoc MeSH
• cyklosporin * farmakologie   MeSH
• hypoxie * metabolismus   MeSH
• infarkt myokardu metabolismus   patologie   prevence a kontrola   MeSH
• krysa rodu rattus MeSH
• potkani Wistar * MeSH
• přechodový pór mitochondriální permeability * metabolismus   MeSH
• reperfuzní poškození myokardu * metabolismus   prevence a kontrola   patologie   MeSH
• srdeční mitochondrie metabolismus   účinky léků   patologie   MeSH
• transportní proteiny mitochondriální membrány metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The cardioprotective effect of ischemic preconditioning (IPC) and ischemic postconditioning (IPoC) in adult hearts is mediated by nitric oxide (NO). During the early developmental period, rat hearts exhibit higher resistance to ischemia-reperfusion (I/R) injury, contain higher levels of serum nitrates, and their resistance cannot be further increased by IPC or IPoC. NOS blocker (L-NAME) lowers their high resistance. Wistar rat hearts (postnatal Days 1 and 10) were perfused according to Langendorff and exposed to 40 min of global ischemia followed by reperfusion with or without IPoC. NO and reactive oxygen species donors (DEA-NONO, SIN-1) and L-NAME were administered. Tolerance to ischemia decreased between Days 1 and 10. DEA-NONO (low concentrations) significantly increased tolerance to I/R injury on both Days 1 and 10. SIN-1 increased tolerance to I/R injury on Day 10, but not on Day 1. L-NAME significantly reduced resistance to I/R injury on Day 1, but actually increased resistance to I/R injury on Day 10. Cardioprotection by IPoC on Day 10 was not affected by either NO donors or L-NAME. It can be concluded that resistance of the neonatal heart to I/R injury is NO dependent, but unlike in adult hearts, cardioprotective interventions, such as IPoC, are most likely NO independent.

• MeSH
• donory oxidu dusnatého farmakologie   MeSH
• ischemické přivykání metody   MeSH
• ischemický postconditioning * metody   MeSH
• krysa rodu rattus MeSH
• molsidomin farmakologie   analogy a deriváty   MeSH
• myokard metabolismus   MeSH
• NG-nitroargininmethylester * farmakologie   MeSH
• novorozená zvířata * MeSH
• oxid dusnatý * metabolismus   MeSH
• potkani Wistar * MeSH
• reperfuzní poškození myokardu * prevence a kontrola   metabolismus   MeSH
• srdce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Ischemická choroba srdeční je hlavní příčinou morbidity a mortality ve vyspělých zemích. Je proto pochopitelné, že zájem experimentálních a klinických kardiologů se v průběhu uplynulých 45 let soustředil na studium možného snížení rozsahu ischemického postižení srdečního svalu. Bylo zjištěno, že klíčovou roli v určení rozsahu ischemicko/reperfuzního (I/R) poškození hraje porucha funkce mitochondrií, zvláště pak otevření mitochondriálního póru (mPTP). Adaptace na chronickou hypoxii dlouhodobě významně zvyšuje odolnost srdečního svalu k I/R poškození; tento protektivní efekt je doprovázen stabilizací hypoxií-indukovaného faktoru 1alfa (HIF-1alfa). Cílem projektu je proto zjistit, zda stabilizace HIF-1alfa je klíčovým mechanismem zvýšené odolnosti srdce k I/R poškození a analyzovat vliv geneticky a funkčně změněných hladin HIF-1alfa na funkci mitochondrií, především pak na pravděpodobnost otevření mPTP póru při I/R poškození. Očekávané výsledky by měly přispět k objasnění mechanismů, které se uplatňují v protekci ischemického myokardu.; Ischemic heart disease is the leading cause of mortality in developed countries. It is, therefore, not surprising that both experimental and clinical cardiologists have been focused on effective protection of the heart against ischemia/reperfusion (I/R) injury. It is widely accepted that mitochondrial dysfunction, mainly mitochondrial permeability transition pore (mPTP) opening, plays a major role in cardiac I/R injury. Adaptation to chronic hypoxia is a natural stimulus conferring a long-lasting cardioprotection against I/R. Its cardioprotective effects are associated with stabilization of hypoxia-inducible factor 1alpha (HIF-1alpha). The aim of the present study is, therefore, to determine whether HIF-1alpha stabilization is the key mechanism increasing myocardial tolerance to I/R injury and to analyze the effect of genetically and functionally modified HIF-1alpha levels on mitochondrial function and mPTP opening during I/R injury. These results should contribute to the clarification of mechanisms participating in the protection of the ischemic heart.

• Klíčová slova
• infarkt myokardu, kardioprotekce, myocardial infarction, cardioprotection, Mitochondrie, Mitochondria, chronická hypoxie, hypoxií-indukovaný faktor 1alfa, chronic hypoxia, hypoxia-inducible factor 1alpha,

• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

While 3-N-butylphthalide (NBP) has demonstrated notable cardioprotective effects, its precise role in mitigating myocardial arrhythmia following ischemia/reperfusion (IR) injury in diabetes remains unclear. This study aimed to explore the potential mechanisms through which NBP mitigates reperfusion-induced myocardial arrhythmia in diabetic rats, with a particular focus on mitochondrial function and biogenesis, endoplasmic reticulum (ER) stress, and oxidative/inflammatory responses. Sixty Sprague-Dawley rats were divided into non-diabetic and diabetic groups, subjected to in-vivo myocardial IR injury, and treated with NBP (100 mg/kg, intraperitoneally) through different modalities: preconditioning, postconditioning, or a combination of both. Electrocardiography (ECG) was employed to assess the incidence and severity of arrhythmia. Fluorometric, Western blotting and ELISA analyses were utilized to measure the mitochondrial, ER stress, and cellular outcomes. Treatment of non-diabetic rats with NBP in preconditioned, postconditioned, and combined approaches significantly reduced cardiotroponin-I and the frequency and severity of arrhythmias induced by IR injury. However, only the combined preconditioning plus postconditioning approach of NBP had protective and antiarrhythmic effects in diabetic rats, in an additive manner. Moreover, the NBP combined approach improved mitochondrial function and upregulated the expression of PGC-1?, Sirt1, and glutathione while concurrently downregulating ER stress and oxidative and pro-inflammatory-related proteins in diabetic rats. In conclusion, the combined approach of NBP treatment was effective in mitigating myocardial arrhythmia in diabetic rats. This approach coordinates interactions within the mitochondria-endoplasmic reticulum network and inhibits oxidative and inflammatory mediators, offering a promising strategy for managing myocardial arrhythmia in diabetic patients. Key words: Myocardial Infarction, Mitochondria, Arrhythmia, Reperfusion, Diabetes, Ischemia.

• MeSH
• antiarytmika farmakologie   terapeutické užití   MeSH
• benzofurany * farmakologie   terapeutické užití   MeSH
• experimentální diabetes mellitus * metabolismus   farmakoterapie   komplikace   MeSH
• krysa rodu rattus MeSH
• oxidační stres * účinky léků   MeSH
• potkani Sprague-Dawley * MeSH
• reperfuzní poškození myokardu * metabolismus   farmakoterapie   prevence a kontrola   MeSH
• srdeční arytmie * etiologie   prevence a kontrola   metabolismus   farmakoterapie   MeSH
• srdeční mitochondrie metabolismus   účinky léků   MeSH
• stres endoplazmatického retikula * účinky léků   MeSH
• zánět metabolismus   farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

AIM: The transcriptional factor HIF-1α is recognized for its contribution to cardioprotection against acute ischemia/reperfusion injury. Adaptation to chronic hypoxia (CH) is known to stabilize HIF-1α and increase myocardial ischemic tolerance. However, the precise role of HIF-1α in mediating the protective effect remains incompletely understood. METHODS: Male wild-type (WT) mice and mice with partial Hif1a deficiency (hif1a +/-) were exposed to CH for 4 weeks, while their respective controls were kept under normoxic conditions. Subsequently, their isolated perfused hearts were subjected to ischemia/reperfusion to determine infarct size, while RNA-sequencing of isolated cardiomyocytes was performed. Mitochondrial respiration was measured to evaluate mitochondrial function, and western blots were performed to assess mitophagy. RESULTS: We demonstrated enhanced ischemic tolerance in WT mice induced by adaptation to CH compared with their normoxic controls and chronically hypoxic hif1a +/- mice. Through cardiomyocyte bulk mRNA sequencing analysis, we unveiled significant reprogramming of cardiomyocytes induced by CH emphasizing mitochondrial processes. CH reduced mitochondrial content and respiration and altered mitochondrial ultrastructure. Notably, the reduced mitochondrial content correlated with enhanced autophagosome formation exclusively in chronically hypoxic WT mice, supported by an increase in the LC3-II/LC3-I ratio, expression of PINK1, and degradation of SQSTM1/p62. Furthermore, pretreatment with the mitochondrial division inhibitor (mdivi-1) abolished the infarct size-limiting effect of CH in WT mice, highlighting the key role of mitophagy in CH-induced cardioprotection. CONCLUSION: These findings provide new insights into the contribution of HIF-1α to cardiomyocyte survival during acute ischemia/reperfusion injury by activating the selective autophagy pathway.

• MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa * metabolismus   genetika   MeSH
• fyziologická adaptace fyziologie   MeSH
• hypoxie * metabolismus   MeSH
• infarkt myokardu * metabolismus   patologie   genetika   MeSH
• kardiomyocyty metabolismus   patologie   MeSH
• mitofagie * fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Muscarinic acetylcholine receptors are metabotropic G-protein coupled receptors. Muscarinic receptors in the cardiovascular system play a central role in its regulation. Particularly M2 receptors slow down the heart rate by reducing the impulse conductivity through the atrioventricular node. In general, activation of muscarinic receptors has sedative effects on the cardiovascular system, including vasodilation, negative chronotropic and inotropic effects on the heart, and cardioprotective effects, including antifibrillatory effects. First, we review the signaling of individual subtypes of muscarinic receptors and their involvement in the physiology and pathology of the cardiovascular system. Then we review age and disease-related changes in signaling via muscarinic receptors in the cardiovascular system. Finally, we review molecular mechanisms involved in cardioprotection mediated by muscarinic receptors leading to negative chronotropic and inotropic and antifibrillatory effects on heart and vasodilation, like activation of acetylcholine-gated inward-rectifier K+-currents and endothelium-dependent and -independent vasodilation. We relate this knowledge with well-established cardioprotective treatments by vagal stimulation and muscarinic agonists. It is well known that estrogen exerts cardioprotective effects against atherosclerosis and ischemia-reperfusion injury. Recently, some sex hormones and neurosteroids have been shown to allosterically modulate muscarinic receptors. Thus, we outline possible treatment by steroid-based positive allosteric modulators of acetylcholine as a novel pharmacotherapeutic tactic. Keywords: Muscarinic receptors, Muscarinic agonists, Allosteric modulation, Cardiovascular system, Cardioprotection, Steroids.

• MeSH
• agonisté muskarinových receptorů farmakologie   MeSH
• kardiotonika farmakologie   terapeutické užití   MeSH
• lidé MeSH
• receptory muskarinové * metabolismus   MeSH
• vazodilatace fyziologie   účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH