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Study of the mechanisms of action of phenolic compounds on vascular smooth muscle
Alves Dias, Patrícia Alexandra ; Mladěnka, Přemysl (advisor) ; Kyselovič, Ján (referee) ; Štengl, Milan (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Training Workplace Department of Pharmacology and Toxicology Doctoral Degree Program Pharmacology and Toxicology Candidate Patrícia Alexandra Alves Dias, M.Sc. Supervisor prof. Přemysl Mladěnka, Pharm.D., Ph.D. Advisor assoc. prof. Jana Pourová, Pharm.D., Ph.D. Title of Doctoral Thesis Study of the mechanisms of action of phenolic compounds on the vascular smooth muscle Cardiovascular diseases including hypertension, coronary artery disease, peripheral artery disease, and cerebrovascular disease remain the leading cause of death worldwide. In addition, discouraging estimations have suggested a future increase in the number of cardiovascular patients. Thus, novel treatment modalities are clearly needed to prevent or reverse these epidemic trends. Phenolic compounds contain one or more hydroxyl groups bound to a benzene ring. This class of chemicals includes: a) natural compounds (e.g., dietary polyphenols and small phenolic metabolites) referred to as nutraceuticals due to their claimed health-promoting effects and b) synthetic compounds (e.g., bisphenols) which, on the contrary, have been suggested to negatively affect human health. Even if there are claims that polyphenol-rich diet is associated with cardioprotective effects, important...
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Anthracycline cardiotoxicity and study of new pharmacological cardioprotectants
Pokorná, Zuzana ; Štěrba, Martin (advisor) ; Mičuda, Stanislav (referee) ; Štengl, Milan (referee)
Title: Anthracycline cardiotoxicity and study of new pharmacological cardioprotectants This Ph.D. thesis is a commented collection of 3 original articles published in international journals. The first part deals with cardiotoxicity of proteasome inhibitors (PI) bortezomib and carfilzomib, which are biologically targeted drugs with a suspected risk of cardiotoxicity and heart failure (HF). As PIs are now being combined with anthracycline (ANT) anticancer drugs, which are well known for their damaging impact on the heart, a special attention was paid to this potentially risky combination. In vitro experiments with primary cardiomyocytes yielded different results depending on the employment of either neonatal or adult rat cardiomyocyte model (NVCM and AVCM, respectively). In particular, both PIs significantly increased toxicity of ANTs to NVCM, but not to AVCM, even though they inhibited proteasome activity in AVCM even more effectively. Both PIs administered in maximally tolerated doses in combination with ANT did not have a significant impact on the development of chronic ANT cardiotoxicity and HF in rabbits. Both PIs induced significant but relatively short-lived inhibition of proteasome activity in the heart, which might explain why they did not have a significant impact on a protein homeostasis...
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The role of renal dysfunction in pathophysiology of congestive heart failure progression: preclinical animal studies
Kala, Petr ; Veselka, Josef (advisor) ; Štengl, Milan (referee) ; Štěrba, Martin (referee)
The role of renal dysfunction in pathophysiology of congestive heart failure progression: preclinical animal studies. Abstract The thesis describes effects and pharmacological targets of eicosanoids, especially epoxyeicosatrienoic acids (EETs) that are epoxygenase metabolites of arachidonic acid (AA), in animal model of congestive heart failure (CHF) induced by volume overload via aorto- caval fistula (ACF) in hypertensive transgenic rats (TGR). Our data show that ACF TGR exhibits tissue deficiency of EETs in the left ventricle and kidney, probably mainly caused by increased EETs degradation by soluble epoxide hydrolase (sEH). Treatment by orally active EETs analogue (EET-A) improved the survival rate in ACF TGR compared to placebo. However, after adding EET-A to angiotensin-convertase enzyme inhibitor (ACEi) treatment, the survival of ACF TGR only tended to improve compared with the effects of EET-A or ACEi given alone. The protective effects of EET-A treatment were mediated by improving cardiac parameters and reducing lung congestion, not dominantly by renal mechanisms. We also found that among male (not in female) the combination of sEH inhibitor (sEHi) and ACEi treatment worsened the mortality of ACF TGR compared to ACEi monotherapy. Our data support the notion that targeting the CYP-dependent...
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Anthracycline Cardiotoxicity and Study of New Pharmacological Cardioprotectants
Pokorná, Zuzana ; Štěrba, Martin (advisor) ; Červenka, Luděk (referee) ; Štengl, Milan (referee)
Title: Anthracycline cardiotoxicity and study of new pharmacological cardioprotectants This Ph.D. thesis is a commented collection of 3 original articles published in international journals. The first part deals with cardiotoxicity of proteasome inhibitors (PI) bortezomib and carfilzomib, which are biologically targeted drugs with a suspected risk of cardiotoxicity and heart failure (HF). As PIs are now being combined with anthracycline (ANT) anticancer drugs, which are well known for their damaging impact on the heart, a special attention was paid to this potentially risky combination. In vitro experiments with primary cardiomyocytes yielded different results depending on the employment of either neonatal or adult rat cardiomyocyte model (NVCM and AVCM, respectively). In particular, both PIs significantly increased toxicity of ANTs to NVCM, but not to AVCM, even though they inhibited proteasome activity in AVCM even more effectively. Both PIs administered in maximally tolerated doses in combination with ANT did not have a significant impact on the development of chronic ANT cardiotoxicity and HF in rabbits. Both PIs induced significant but relatively short-lived inhibition of proteasome activity in the heart, which might explain why they did not have a significant impact on a protein homeostasis...
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Myocardial Electrophysiology in Health and Disease
Jarkovská, Dagmar ; Štengl, Milan (advisor) ; Stankovičová, Tatiana (referee) ; Bébarová, Markéta (referee)
This dissertation consists of three parts describing electrophysiological and contractile changes of the myocardium in sepsis, acidosis, and propofol-induced anaesthesia. The first part is focused on heart rate variability analysis in a clinically relevant porcine model of sepsis/septic shock. Heart rate variability showed fast decrease few hours after sepsis induction which preceded changes in clinical parameters commonly used for sepsis diagnosis. The same fast kinetics of heart rate variability were demonstrated in progressive septic shock and in sepsis without serious multiorgan failure. Based on these results, it seems that heart rate variability could represent an early diagnostic tool in patients threatened with sepsis. In the second part of this thesis acidosis and its effects on the cardiovascular system are analysed. Metabolic and hypercapnic acidoses were examined in domestic pigs using hemodynamic in vivo measurements and in vitro experiments focused on electrophysiology and contractility of the heart. Both types of acidosis affected circulation and reduced myocardial contractility; hence it could limit therapeutic use of hypercapnic acidosis. The thesis is completed by a study of the effect of propofol, an anaesthetic used in two above mentioned studies. In rat ventricular tissue in...
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The impact of positive inotropic and antiarrhythmic drugs on cardiovascular system
Kočková, Radka ; Linhart, Aleš (advisor) ; Janoušek, Jan (referee) ; Štengl, Milan (referee)
Heart rate changes mediate the embryotoxic effect of antiarrhythmic drugs in the chick embryo A significant increase in cardiovascular medication use during pregnancy has occurred in recent years but only limited evidence on its safety profile is available. We hypothesized that drug-induced bradycardia is the leading mechanism of developmental toxicity. We tested metoprolol, carvedilol, or ivabradine for embryotoxicity and their acute effect on chick embryonic model. We used video microscopy and ultrasound biomicroscopy. Significant dose-dependent mortality was achieved in embryos injected with carvedilol and ivabradine. In ED4 embryos, metoprolol, carvedilol and ivabradine reduced the heart rate by 33%, 27%, and 55%, respectively, compared to controls (6%). In ED8 embryos this effect was more pronounced with a heart rate reduction by 71%, 54%, 53%, respectively (controls 36%). Cardiac output decreased in all tested groups but only proved significant in the metoprolol group in ED8 embryos. The number of -adrenergic receptors showed a downward tendency during embryonic development but a negative chronotropic effect of tested drugs was increasingly pronounced with embryonic maturity. This effect was associated with reduced cardiac output in chick embryos, probably leading to premature death....
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The role of arachidonic acid metabolites in regulation of blood pressure in experimental models of angiotensin II- dependent hypertension
Jíchová, Šárka ; Červenka, Luděk (advisor) ; Zicha, Josef (referee) ; Štengl, Milan (referee)
Introduction: Two major product groups originate from the arachidonic acid metabolic pathway of cytochromes P450: epoxyeicosatrienoic acid (EETs) and 19 and 20-hydroxyeicosatetraenoic acid (19- and 20-HETE). These metabolites play an important role in the regulation of blood pressure, inflammatory responses, regulation of sodium excretion and other crucial physiological processes. Hypothesis: Our studies were based on the hypothesis that abnormalities in the production and function of these cytochrome P450 metabolites significantly contribute to the pathophysiology of hypertension development, in particular in the angiotensin II-dependent models. Objective: To investigate if the increased bioavailability of the above-mentioned metabolites in the kidney tissue will result in blood pressure reduction in the ANG II - dependent rat model of hypertension. Methods: The two methods to increase the concentration of EETs was chosen. In the first part of the study, we administered a soluble epoxide hydrolase inhibitor cAUCB [cis-4- [4- (3-adamantan-1-yl- ureido) cyclohexyloxy] benzoic acid, at a dose of 26 mg.l-1 administered in drinking water], an enzyme responsible for inactivation of biologically active forms of EETs. In the second series of the experiments we applied a synthetic EET analogue, called...
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Myocardial Electrophysiology in Health and Disease
Jarkovská, Dagmar ; Štengl, Milan (advisor) ; Stankovičová, Tatiana (referee) ; Bébarová, Markéta (referee)
This dissertation consists of three parts describing electrophysiological and contractile changes of the myocardium in sepsis, acidosis, and propofol-induced anaesthesia. The first part is focused on heart rate variability analysis in a clinically relevant porcine model of sepsis/septic shock. Heart rate variability showed fast decrease few hours after sepsis induction which preceded changes in clinical parameters commonly used for sepsis diagnosis. The same fast kinetics of heart rate variability were demonstrated in progressive septic shock and in sepsis without serious multiorgan failure. Based on these results, it seems that heart rate variability could represent an early diagnostic tool in patients threatened with sepsis. In the second part of this thesis acidosis and its effects on the cardiovascular system are analysed. Metabolic and hypercapnic acidoses were examined in domestic pigs using hemodynamic in vivo measurements and in vitro experiments focused on electrophysiology and contractility of the heart. Both types of acidosis affected circulation and reduced myocardial contractility; hence it could limit therapeutic use of hypercapnic acidosis. The thesis is completed by a study of the effect of propofol, an anaesthetic used in two above mentioned studies. In rat ventricular tissue in...
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The impact of positive inotropic and antiarrhythmic drugs on cardiovascular system
Kočková, Radka ; Linhart, Aleš (advisor) ; Janoušek, Jan (referee) ; Štengl, Milan (referee)
Heart rate changes mediate the embryotoxic effect of antiarrhythmic drugs in the chick embryo A significant increase in cardiovascular medication use during pregnancy has occurred in recent years but only limited evidence on its safety profile is available. We hypothesized that drug-induced bradycardia is the leading mechanism of developmental toxicity. We tested metoprolol, carvedilol, or ivabradine for embryotoxicity and their acute effect on chick embryonic model. We used video microscopy and ultrasound biomicroscopy. Significant dose-dependent mortality was achieved in embryos injected with carvedilol and ivabradine. In ED4 embryos, metoprolol, carvedilol and ivabradine reduced the heart rate by 33%, 27%, and 55%, respectively, compared to controls (6%). In ED8 embryos this effect was more pronounced with a heart rate reduction by 71%, 54%, 53%, respectively (controls 36%). Cardiac output decreased in all tested groups but only proved significant in the metoprolol group in ED8 embryos. The number of -adrenergic receptors showed a downward tendency during embryonic development but a negative chronotropic effect of tested drugs was increasingly pronounced with embryonic maturity. This effect was associated with reduced cardiac output in chick embryos, probably leading to premature death....
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