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Circadian regulation of the cardiovascular system
Nováková, Jessica ; Bendová, Zdeňka (advisor) ; Galatík, František (referee)
Circadian system consist of the main circadian oscillator and the peripheral oscillators. Their function is to enable the adaptation of living organisms to the diurnal environmental changes. Circadian system regulates rhythmical expression of genes in nearly every cell of the body, thereby affecting both the physiological and behavioural processes of mammals and other animals. This bachelor's thesis summarizes a knowledge from experiments which led to the demonstration of circadian rhytms in cardiovascular system. To introduce the topic, the first discoveries of circadian rhythms in the cardiovascular system are mentioned. Then, we focus on the circadian rhythms in cardiomyocytes, vascular endothelial cells and in vascular smooth muscle cells. Another focal point of my thesis is the role of transcription factor Krüppel-like factor 15. Circadian regulation of the cardiovascular system is important for the proper function of the heart and blood vessels. Circadian disruption can cause severe pathophysiological and cardiovascular conditions, such as ventricular hypertrophy, hypertension, atherosclerosis, myocardial infarction or coronary artery disease. Key words: circadian, clock genes, cardiovascular system, cardiomyocytes, vascular endothelial cells, vascular smooth muscle cells, Krüppel-like factor...
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Excitation-Contraction and Excitation-Transcription Coupling in Vascular Smooth Muscle Cells: Alterations in Experimental Hypertension and Vascular Remodeling
Misárková, Eliška ; Zicha, Josef (advisor) ; Hock, Miroslav (referee)
Vascular smooth muscle cells (VSMCs) express considerable phenotype plasticity. They are able to change their phenotype in vivo if necessary. It is important to know that during this phenotype switch the expression of transport proteins and channels is modified, which results in significant alteration of Ca2+ signaling in smooth muscle cells. In differentiated cells, which represent contractile phenotype, there are dominant rapid, transient events in intracellular Ca2+ concentration (Ca2+ i), while the resting cytosolic Ca2+ i concentration is low. In differentiated cells these Ca2+ i events are mainly caused by two components of the Ca2+ signalling pathways: 1) extracellular Ca2+ influx via L-type voltage-gated Ca2+ channels (L-type VGCC) in plasma membrane, and 2) depletion of intracellular Ca2+ stores via ryanodin receptors located on sarcoplasmic reticulum. Rapid Ca2+ i oscillations are quickly reduced by numerous Ca2+ ATPases of sarco/endoplasmic reticulum and plasma membrane. Proliferating vascular smooth muscle cells are characterized by a long-lasting Ca2+ i oscillations accompanied by sustained elevation of basal intracellular Ca2+ concentration. During phenotype switch from contractile phenotype to proliferative phenotype there is decreased Ca2+ ATPase activity, and store-operated Ca2+...
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Role of perivascular fat tissue in the development of cardiovascular diseases
Čejková, Soňa ; Ždychová, Jana (advisor) ; Pavlišová, Jana (referee)
Abnormal vascular smooth muscle cell (VSMC) proliferation is thought to play an important role in the pathogenesis of atherosclerosis. Adipocytes produce several paracrine bioactive substances that can affect VSMC growth and migration. Our study focused on the ability of epicardial adipocytes to produce bioactive substances together with studying of direct effect of these substances on the VSMC proliferation rate. The gene expression of human cytokines (IL-6, IL-8, IL-18, RANTES and MCP-1) and adipokines (leptin and adiponectin) was measured in primary cell lines of epicardial and visceral adipocytes, both in undifferentiated and mature statuses. Moreover, adipokine production (IL-6, IL-8, MCP-1, VEGF and adiponectin) in conditioned media obtained from above mentioned primary cell cultures of adipocytes was measured by a Luminex assay. The VSMC proliferation rate was measured after co-culturing with CM obtained from primary cell cultures of adipocytes. The epicardial preadipocytes showed an increased expression of IL-8 (3,25-fold, p<0,05) compared with visceral preadipocytes. The expression of the adiponectin in epicardial preadipocytes was markedly decreased in comparison of the expression in visceral preadipocytes (p< 0,0001). Moreover, the gene expression was dependent on the differentiation...
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Role of Potassium Channels in the Regulation of Vascular Smooth Muscle Tone
Bencze, Michal ; Zicha, Josef (advisor) ; Moravec, Jan (referee)
In smooth muscle cells, potassium channels play an important role in the regulation of the membrane potential of smooth muscle cells, which is closely related to vascular tone. Four different types of K+ channels have been described in vascular smooth muscle cells. Voltagegated K+ channels (KV), which can be open by depolarization. Calcium-activated potassium channels (KCa), from the same gene family, are voltage dependent, and can be activated also by elevated concentration of intracellular Ca2+. Inward rectifying channels (KIR) display negative slope conductance. These channels amplify potassium flow and function as an extracellular K+ sensor. ATP-sensitive K+ channels (KATP) channels provide a link between cell metabolism and membrane potential. Function of K+ channels is also important in endothelium, which produces many vasodilatators and vasoconstrictors. Abnormal expression profile of K+ channels is part of vascular cell membrane remodeling.
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Current possibilities of influence long-term patency of coronary artery bypass grafts
Skalský, Ivo ; Rohn, Vilém (advisor) ; Adamec, Miloš (referee) ; Němec, Petr (referee)
The main complication of aortocoronary reconstruction with vein grafts is restenosis in the course of time. The aim was to assess the effect of a periadventitial polyester system releasing sirolimus on intimal hyperplasia of autologous grafts. The controlled-release system comprises a polyester mesh coated with a sirolimus-eluting copolymer of L lactic acid and ε-caprolactone system designed to be wrapped around an autologous venous graft during its implantation. In vitro sirolimus release and its effects on smooth muscle and endothelial cells were assessed. In vitro, the copolymer-coated polyester mesh released sirolimus over a period of 6 weeks. Mesh-eluted sirolimus inhibited the growth of smooth muscle and endothelial cells in seven-day in vitro experiments. After seven days of sirolimus release from the mesh, smooth muscle and endothelial cell counts decreased by 29% and 75%, respectively, with the cells maintaining high viability. We implanted v. jugularis ext. into a. carotis communis in rabbits. The vein graft was either intact, or was wrapped with a pure polyester mesh, or with a sirolimus-releasing mesh. Three and six weeks after surgery, the veins were subjected to standard histological staining and the thicknesses of the tunica intima, the media and the intima-media complex were...
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Role of Potassium Channels in the Regulation of Vascular Smooth Muscle Tone
Bencze, Michal ; Zicha, Josef (advisor) ; Moravec, Jan (referee)
In smooth muscle cells, potassium channels play an important role in the regulation of the membrane potential of smooth muscle cells, which is closely related to vascular tone. Four different types of K+ channels have been described in vascular smooth muscle cells. Voltagegated K+ channels (KV), which can be open by depolarization. Calcium-activated potassium channels (KCa), from the same gene family, are voltage dependent, and can be activated also by elevated concentration of intracellular Ca2+. Inward rectifying channels (KIR) display negative slope conductance. These channels amplify potassium flow and function as an extracellular K+ sensor. ATP-sensitive K+ channels (KATP) channels provide a link between cell metabolism and membrane potential. Function of K+ channels is also important in endothelium, which produces many vasodilatators and vasoconstrictors. Abnormal expression profile of K+ channels is part of vascular cell membrane remodeling.
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Role of perivascular fat tissue in the development of cardiovascular diseases
Čejková, Soňa ; Ždychová, Jana (advisor) ; Pavlišová, Jana (referee)
Abnormal vascular smooth muscle cell (VSMC) proliferation is thought to play an important role in the pathogenesis of atherosclerosis. Adipocytes produce several paracrine bioactive substances that can affect VSMC growth and migration. Our study focused on the ability of epicardial adipocytes to produce bioactive substances together with studying of direct effect of these substances on the VSMC proliferation rate. The gene expression of human cytokines (IL-6, IL-8, IL-18, RANTES and MCP-1) and adipokines (leptin and adiponectin) was measured in primary cell lines of epicardial and visceral adipocytes, both in undifferentiated and mature statuses. Moreover, adipokine production (IL-6, IL-8, MCP-1, VEGF and adiponectin) in conditioned media obtained from above mentioned primary cell cultures of adipocytes was measured by a Luminex assay. The VSMC proliferation rate was measured after co-culturing with CM obtained from primary cell cultures of adipocytes. The epicardial preadipocytes showed an increased expression of IL-8 (3,25-fold, p<0,05) compared with visceral preadipocytes. The expression of the adiponectin in epicardial preadipocytes was markedly decreased in comparison of the expression in visceral preadipocytes (p< 0,0001). Moreover, the gene expression was dependent on the differentiation...
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Phenotypic plasticity of smooth muscle cells
Misárková, Eliška ; Zicha, Josef (advisor) ; Pácha, Jiří (referee)
Vascular smooth muscle cells display a certain level of phenotype plasticity. Under specific conditions fully differentiated cells are able to undergo dedifferentiation and to restart growth and proliferation. An organ culture method is a useful technique for the analysis of dedifferentiation of vascular smooth muscle cells, because it provides an opportunity for studying the changes in cell phenotype. The aim of this study was to investigate the basic contractile characteristics in rat femoral arteries cultured for different time periods (from one to three days). In addition, the effects of fetal bovine serum (FBS), that contains various growth factors and other biological active molecules, on contractile function were studied. We also tried to attenuate cell dedifferentiation by lowering the calcium influx, because calcium is an important second messenger participating in cell growth and proliferation. To achieve this goal we used cultivation with nifedipine, a voltage-dependent calcium channel inhibitor. The cultivation without FBS slightly decreased arterial contractility, whereas the cultivation with FBS decreased arterial contractility considerably. The major change in contractility of arteries cultivated with FBS occurred approximately within 24 hours of cultivation. The cultivation with...
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Current possibilities of influence long-term patency of coronary artery bypass grafts
Skalský, Ivo ; Rohn, Vilém (advisor) ; Adamec, Miloš (referee) ; Němec, Petr (referee)
The main complication of aortocoronary reconstruction with vein grafts is restenosis in the course of time. The aim was to assess the effect of a periadventitial polyester system releasing sirolimus on intimal hyperplasia of autologous grafts. The controlled-release system comprises a polyester mesh coated with a sirolimus-eluting copolymer of L lactic acid and ε-caprolactone system designed to be wrapped around an autologous venous graft during its implantation. In vitro sirolimus release and its effects on smooth muscle and endothelial cells were assessed. In vitro, the copolymer-coated polyester mesh released sirolimus over a period of 6 weeks. Mesh-eluted sirolimus inhibited the growth of smooth muscle and endothelial cells in seven-day in vitro experiments. After seven days of sirolimus release from the mesh, smooth muscle and endothelial cell counts decreased by 29% and 75%, respectively, with the cells maintaining high viability. We implanted v. jugularis ext. into a. carotis communis in rabbits. The vein graft was either intact, or was wrapped with a pure polyester mesh, or with a sirolimus-releasing mesh. Three and six weeks after surgery, the veins were subjected to standard histological staining and the thicknesses of the tunica intima, the media and the intima-media complex were...
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Excitation-Contraction and Excitation-Transcription Coupling in Vascular Smooth Muscle Cells: Alterations in Experimental Hypertension and Vascular Remodeling
Misárková, Eliška ; Zicha, Josef (advisor) ; Hock, Miroslav (referee)
Vascular smooth muscle cells (VSMCs) express considerable phenotype plasticity. They are able to change their phenotype in vivo if necessary. It is important to know that during this phenotype switch the expression of transport proteins and channels is modified, which results in significant alteration of Ca2+ signaling in smooth muscle cells. In differentiated cells, which represent contractile phenotype, there are dominant rapid, transient events in intracellular Ca2+ concentration (Ca2+ i), while the resting cytosolic Ca2+ i concentration is low. In differentiated cells these Ca2+ i events are mainly caused by two components of the Ca2+ signalling pathways: 1) extracellular Ca2+ influx via L-type voltage-gated Ca2+ channels (L-type VGCC) in plasma membrane, and 2) depletion of intracellular Ca2+ stores via ryanodin receptors located on sarcoplasmic reticulum. Rapid Ca2+ i oscillations are quickly reduced by numerous Ca2+ ATPases of sarco/endoplasmic reticulum and plasma membrane. Proliferating vascular smooth muscle cells are characterized by a long-lasting Ca2+ i oscillations accompanied by sustained elevation of basal intracellular Ca2+ concentration. During phenotype switch from contractile phenotype to proliferative phenotype there is decreased Ca2+ ATPase activity, and store-operated Ca2+...
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