The aim of the study was to clarify the role of the interplay between hypertension and the renin-angiotensin system (RAS) in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. We hypothesized that in the late phase of hypertension with already developed signs of end-organ damage, inappropriate RAS activation could impair cardiac tolerance to I/R injury. Experiments were performed in male Cyp1a1-Ren-2 transgenic rats with inducible hypertension. The early phase of ANG II-dependent hypertension was induced by 5 days and the late phase by the 13 days dietary indole-3-carbinol (I3C) administration. Noninduced rats served as controls. Echocardiography and pressure-volume analysis were performed, angiotensins' levels were measured and cardiac tolerance to ischemia/reperfusion injury was studied. The infarct size was significantly reduced (by 50%) in 13 days I3C-induced hypertensive rats with marked cardiac hypertrophy, this reduction was abolished by losartan treatment. In the late phase of hypertension there are indications of a failing heart, mainly in reduced preload recruitable stroke work (PRSW), but only nonsignificant trends in worsening of some other parameters, showing that the myocardium is in a compensated phase. The influence of the RAS depends on the balance between the vasoconstrictive and the opposed vasodilatory axis. In the initial stage of hypertension, the vasodilatory axis of the RAS prevails, and with the development of hypertension the vasoconstrictive axis of the RAS becomes stronger. We observed a clear effect of AT1 receptor blockade on maximum pressure in left ventricle, cardiac hypertrophy and ANG II levels. In conclusion, we confirmed improved cardiac tolerance to I/R injury in hypertensive hypertrophied rats and showed that, in the late phase of hypertension, the myocardium is in a compensated phase.

• Publikační typ
• časopisecké články MeSH

• Publikační typ
• abstrakt z konference MeSH

Cardiovascular and heart diseases are leading causes of morbidity and mortality. Coronary artery endothelial and vascular dysfunction, inflammation, and mitochondrial dysfunction contribute to progression of heart diseases such as arrhythmias, congestive heart failure, and heart attacks. Classes of fatty acid epoxylipids and their enzymatic regulation by soluble epoxide hydrolase (sEH) have been implicated in coronary artery dysfunction, inflammation, and mitochondrial dysfunction in heart diseases. Likewise, genetic and pharmacological manipulations of epoxylipids have been demonstrated to have therapeutic benefits for heart diseases. Increasing epoxylipids reduce cardiac hypertrophy and fibrosis and improve cardiac function. Beneficial actions for epoxylipids have been demonstrated in cardiac ischemia reperfusion injury, electrical conductance abnormalities and arrhythmias, and ventricular tachycardia. This review discusses past and recent findings on the contribution of epoxylipids in heart diseases and the potential for their manipulation to treat heart attacks, arrhythmias, ventricular tachycardia, and heart failure.

• MeSH
• epoxid hydrolasy antagonisté a inhibitory   metabolismus   MeSH
• epoxidové sloučeniny chemie   metabolismus   MeSH
• infarkt myokardu farmakoterapie   enzymologie   metabolismus   MeSH
• inhibitory enzymů terapeutické užití   MeSH
• komorová tachykardie farmakoterapie   enzymologie   metabolismus   MeSH
• lidé MeSH
• mastné kyseliny metabolismus   MeSH
• nemoci srdce farmakoterapie   enzymologie   metabolismus   MeSH
• rozpustnost MeSH
• srdeční arytmie farmakoterapie   enzymologie   metabolismus   MeSH
• srdeční selhání farmakoterapie   enzymologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH

N6-methyladenosine (m6A) is an abundant mRNA modification affecting mRNA stability and protein expression. It is a highly dynamic process, and its outcomes during postnatal heart development are poorly understood. Here we studied m6A machinery in the left ventricular (LV) myocardium of Fisher344 male and female rats (postnatal days one to ninety; P1-P90) using Western Blot. A downward pattern of target protein levels (demethylases FTO and ALKBH5, methyltransferase METTL3, reader YTHDF2) was revealed in male and female rat LVs during postnatal development. On P1, the FTO protein level was significantly higher in male LVs compared to females.

• MeSH
• krysa rodu rattus MeSH
• myokard * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Mutations of the TMEM70 gene disrupt the biogenesis of the ATP synthase and represent the most frequent cause of autosomal recessive encephalo-cardio-myopathy with neonatal onset. Patient tissues show isolated defects in the ATP synthase, leading to the impaired mitochondrial synthesis of ATP and insufficient energy provision. In the current study, we tested the efficiency of gene complementation by using a transgenic rescue approach in spontaneously hypertensive rats with the targeted Tmem70 gene (SHR-Tmem70ko/ko), which leads to embryonic lethality. We generated SHR-Tmem70ko/ko knockout rats expressing the Tmem70 wild-type transgene (SHR-Tmem70ko/ko,tg/tg) under the control of the EF-1α universal promoter. Transgenic rescue resulted in viable animals that showed the variable expression of the Tmem70 transgene across the range of tissues and only minor differences in terms of the growth parameters. The TMEM70 protein was restored to 16-49% of the controls in the liver and heart, which was sufficient for the full biochemical complementation of ATP synthase biogenesis as well as for mitochondrial energetic function in the liver. In the heart, we observed partial biochemical complementation, especially in SHR-Tmem70ko/ko,tg/0 hemizygotes. As a result, this led to a minor impairment in left ventricle function. Overall, the transgenic rescue of Tmem70 in SHR-Tmem70ko/ko knockout rats resulted in the efficient complementation of ATP synthase deficiency and thus in the successful genetic treatment of an otherwise fatal mitochondrial disorder.

• Publikační typ
• časopisecké články MeSH

Aging attenuates cardiac tolerance to ischemia/reperfusion (I/R) associated with defects in protective cell signaling, however, the onset of this phenotype has not been completely investigated. This study aimed to compare changes in response to I/R and the effects of remote ischemic preconditioning (RIPC) in the hearts of younger adult (3 months) and mature adult (6 months) male Wistar rats, with changes in selected proteins of protective signaling. Langendorff-perfused hearts were exposed to 30 min I/120 min R without or with prior three cycles of RIPC (pressure cuff inflation/deflation on the hind limb). Infarct size (IS), incidence of ventricular arrhythmias and recovery of contractile function (LVDP) served as the end points. In both age groups, left ventricular tissue samples were collected prior to ischemia (baseline) and after I/R, in non-RIPC controls and in RIPC groups to detect selected pro-survival proteins (Western blot). Maturation did not affect post-ischemic recovery of heart function (Left Ventricular Developed Pressure, LVDP), however, it increased IS and arrhythmogenesis accompanied by decreased levels and activity of several pro-survival proteins and by higher levels of pro-apoptotic proteins in the hearts of elder animals. RIPC reduced the occurrence of reperfusion-induced ventricular arrhythmias, IS and contractile dysfunction in younger animals, and this was preserved in the mature adults. RIPC did not increase phosphorylated protein kinase B (p-Akt)/total Akt ratio, endothelial nitric oxide synthase (eNOS) and protein kinase Cε (PKCε) prior to ischemia but only after I/R, while phosphorylated glycogen synthase kinase-3β (GSK3β) was increased (inactivated) before and after ischemia in both age groups coupled with decreased levels of pro-apoptotic markers. We assume that resistance of rat heart to I/R injury starts to already decline during maturation, and that RIPC may represent a clinically relevant cardioprotective intervention in the elder population.

• MeSH
• fosforylace MeSH
• GSK3B genetika   metabolismus   MeSH
• hemodynamika MeSH
• ischemické přivykání * MeSH
• krysa rodu rattus MeSH
• myokard metabolismus   MeSH
• potkani Wistar MeSH
• proteinkinasa C-epsilon genetika   metabolismus   MeSH
• protoonkogenní proteiny c-akt genetika   metabolismus   MeSH
• reperfuzní poškození myokardu metabolismus   patologie   MeSH
• stárnutí MeSH
• synthasa oxidu dusnatého, typ III genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The new antidiabetic drugs, gliflozins, inhibit sodium-glucose transporter-2 in renal proximal tubules promoting glucose and sodium excretion. This leads not only to a significant improvement of glucose control but also to the reduction of blood pressure and body weight in both diabetic patients and experimental models. We examined whether these beneficial effects can also be achieved in a non-diabetic hypertensive model, namely in Ren-2 transgenic rats (TGR). Adult 6-month-old hypertensive TGR and their normotensive controls (Hannover Sprague-Dawley rats), were either untreated or treated with empagliflozin (10 mg/kg/day) for two months. Telemetric blood pressure monitoring, renal parameters as well as cardiac function via echocardiography were analyzed during the experiment. At the end of the study, the contribution of major vasoactive systems to blood pressure maintenance was studied. Metabolic parameters and markers of oxidative stress and inflammation were also analyzed. Empagliflozin had no effect on plasma glucose level but partially reduced blood pressure in TGR. Although food consumption was substantially higher in empagliflozin-treated TGR compared to the untreated animals, their body weight and the amount of epididymal and perirenal fat was decreased. Empagliflozin had no effect on proteinuria, but it decreased plasma urea, attenuated renal oxidative stress and temporarily increased urinary urea excretion. Several metabolic (hepatic triglycerides, non-esterified fatty acids, insulin) and inflammatory (TNF-α, leptin) parameters were also improved by empagliflozin treatment. By contrast, echocardiography did not reveal any effect of empagliflozin on cardiac function. In conclusion, empagliflozin exerted beneficial antihypertensive, anti-inflammatory and metabolic effects also in a non-diabetic hypertensive model.

• MeSH
• adipozita účinky léků   MeSH
• antiflogistika farmakologie   MeSH
• antihypertenziva farmakologie   MeSH
• antioxidancia farmakologie   MeSH
• benzhydrylové sloučeniny farmakologie   MeSH
• energetický metabolismus účinky léků   MeSH
• glukosidy farmakologie   MeSH
• hmotnostní úbytek účinky léků   MeSH
• hypertenze farmakoterapie   genetika   metabolismus   patofyziologie   MeSH
• krevní tlak účinky léků   MeSH
• modely nemocí na zvířatech MeSH
• potkani Sprague-Dawley MeSH
• potkani transgenní MeSH
• renin genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Increased level of C-reactive protein (CRP) is a risk factor for cardiovascular diseases, including myocardial infarction and hypertension. Here, we analyzed the effects of CRP overexpression on cardiac susceptibility to ischemia/reperfusion (I/R) injury in adult spontaneously hypertensive rats (SHR) expressing human CRP transgene (SHR-CRP). Using an in vivo model of coronary artery occlusion, we found that transgenic expression of CRP predisposed SHR-CRP to repeated and prolonged ventricular tachyarrhythmias. Excessive ischemic arrhythmias in SHR-CRP led to a significant reduction in infarct size (IS) compared with SHR. The proarrhythmic phenotype in SHR-CRP was associated with altered heart and plasma eicosanoids, myocardial composition of fatty acids (FAs) in phospholipids, and autonomic nervous system imbalance before ischemia. To explain unexpected IS-limiting effect in SHR-CRP, we performed metabolomic analysis of plasma before and after ischemia. We also determined cardiac ischemic tolerance in hearts subjected to remote ischemic perconditioning (RIPer) and in hearts ex vivo. Acute ischemia in SHR-CRP markedly increased plasma levels of multiple potent cardioprotective molecules that could reduce IS at reperfusion. RIPer provided IS-limiting effect in SHR that was comparable with myocardial infarction observed in naïve SHR-CRP. In hearts ex vivo, IS did not differ between the strains, suggesting that extra-cardiac factors play a crucial role in protection. Our study shows that transgenic expression of human CRP predisposes SHR-CRP to excess ischemic ventricular tachyarrhythmias associated with a drop of pump function that triggers myocardial salvage against lethal I/R injury likely mediated by protective substances released to blood from hypoxic organs and tissue at reperfusion.

• MeSH
• akční potenciály MeSH
• C-reaktivní protein genetika   metabolismus   MeSH
• fibrilace komor etiologie   metabolismus   patofyziologie   MeSH
• hypertenze komplikace   metabolismus   patofyziologie   MeSH
• komorová tachykardie etiologie   metabolismus   patofyziologie   MeSH
• krevní tlak MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myokard metabolismus   patologie   MeSH
• potkani inbrední SHR MeSH
• potkani transgenní MeSH
• reperfuzní poškození myokardu etiologie   metabolismus   patofyziologie   prevence a kontrola   MeSH
• srdeční frekvence MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Experimentální i klinická pozorování prokázala, že struktura a funkce mužského a ženského (resp. samčího a samičího) srdce se významným způsobem liší, a to jak za fyziologických, tak patologických podmínek. Významné pohlavní rozdíly v citlivosti srdečního svalu k ischemii jsou toho nejlepším dokladem: dospělé mužské srdce je ve srovnání s ženským (do menopauzy) podstatně citlivější. Závažnost těchto rozdílů potvrzuje fakt, že množství prací, které se touto problematikou zabývají, v posledních letech strmě stoupá. Detailní molekulární a buněčné mechanismy odpovědné za pohlavní rozdíly na své objasnění teprve čekají; je však zřejmé, že odlišnosti není možno vysvětlit pouze účinkem estrogenů. V posledních letech se objevila nová nadějná hypotéza, jež naznačuje, že na pohlavních rozdílech v odolnosti srdečního svalu k nedostatku kyslíku se mohou výrazným způsobem podílet mitochondrie. Jedno je však jisté: pohlavní rozdíly jsou tak závažné, že by na ně měl být již dnes brán zřetel v klinické praxi při volbě optimálních diagnostických a lé-čebných postupů.

Experimental and clinical studies have clearly demonstrated signifi cant sex differences in myocardial structure and function under normal and pathological conditions. The best examples are signifi cant sex differences in cardiac tolerance to ischemia-reperfusion injury: adult male hearts are more susceptible as compared to pre-menopausal female heart. The importance of these fi ndings is documented by the increasing number of publications on this topic during the last years. Detailed cellular and molecular mechanisms, responsible for sex differences are, unfortunately, still not known; it has been stressed that estrogens are not the only factor involved. Recently, a new hypothesis has been developed, suggesting an important role of cardiac mitochondria. 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.

• Klíčová slova
• pohlavní rozdíly,
• MeSH
• estrogeny MeSH
• ischemická choroba srdeční * etiologie   MeSH
• lidé MeSH
• mitochondrie MeSH
• pohlaví MeSH
• srdce fyziologie   patofyziologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH