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The role of cold acclimation in activation of adrenegic and thyrode signalling pathway in rat myocardium
Tibenská, Veronika
Despite advances in research and therapy, cardiovascular diseases are still the leading cause of death worldwide. A closer understanding of the endogenous protective mechanism may improve pharmacological interventions for the treatment of heart diseases. Cold acclimation or hardening has strong potential for reducing cardiovascular risk and the literature shows that it stimulates the β-adrenergic and thyroid systems in tissues. At the same time, the adrenergic system in the heart is one of the main regulators of cardiac activity. However, these signaling pathways have surprisingly not been studied at the protein level in the heart yet, and no studies can be found on the subject matter in current literature. Our results show a reduced infarct size induced by ischemic injury in cold-acclimated rats (CA) at 8 ř C for 5 weeks and then returning to normothermic conditions for 2 weeks (CAR). The aim of this dissertation is to determine, the degree of involvement of the adrenergic system in the myocardium during acclimation after 3 days, 10 days, 5 weeks of CA and subsequent CAR at the level of all three β-adrenergic receptor isoforms (β-ARs) and their signaling pathways. The results show unchanged signaling of β1-AR-Gs-adenylyl cyclase-protein kinase A in the cardioprotective regimes CA and CAR, whose...
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Cold adaptation of snow algae: the role of changes in the composition of fatty acids
Dřízhalová, Marie ; Nedbalová, Linda (advisor) ; Němcová, Yvonne (referee)
Snow algae as typical extremophiles are good model organisms for study of adaptation for life on the boundary of physiological possibilities. So far, it is not clear, how these microorganisms ensure on the molecular level the optimization of photosynthetic processes in conditions around 0 řC, often with very high light intensity. The aim of this work was to find out light and temperature growth optima of two less studied strains and to assess the composition of fatty acids in selected psychrophilic and psychrotrophic strains from the genera Chloromonas and Chlamydomonas (Chlamydomonadales, Chlorophyta) from culture collections UTEX and CCCryo and collections in Europe including the Czech Republic and Slovakia. Using crossed gradients method, this thesis describes optimal temperature and light conditions of two strains of snow algae isolated from sites in the Krkonoše Mountains that are characterized by different ecological conditions. The strain Chloromonas reticulata Luční originates from alpine zone and according to its growth characteristics, it can be classified as psychrotrophic alga requiring high light. The second tested strain was Chloromonas pichinchae Meandry from forest environment, which is also characterized as psychrotrophic, In contrast to previous strain, it grows in a wide range of...
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Ischemia-reperfusion injury in cold acclimated rats
Vebr, Pavel ; Žurmanová, Jitka (advisor) ; Alánová, Petra (referee)
The effect of cold acclimation on body of mammals has been studied for many decades by using relatively low temperatures for acclimation (6-10 řC). The results of these experiments have shown the important role of the adrenergic and thyroid system during acclimation and negative impact on renal system at the same time. In contrast, a recent study on winter swimmers suggests a possibility of positive influence of hardening on cardiovascular system. There is no available study investigating a relationship between cold adaptation and ischemia-reperfusion injury. The aim of this study was to establish a protocol of isolated rat heart and its fixation at our workplace. Furthermore, to find the impact of mild cold acclimation on the ischemia-reperfusion injury of rat. Methods of ex vivo heart perfusion and fixation were successfully established. The effect of 5 weeks long cold acclimation in 10 ± 2 řC on left ventricle ischemia-reperfusion injury was observed. Powered by TCPDF (www.tcpdf.org)
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Cold adaptation mechanisms in microorganisms
Dřízhalová, Marie ; Nedbalová, Linda (advisor) ; Kvíderová, Jana (referee)
On our planet there are vast areas, where the average temperature does not exceed 5 řC. They are also many places, where the temperature often drops below zero. Not every living organism is able to live in these conditions. The ability to survive in cold region and succefully colonize, such presumably adverse environment requires particular evolutionary adaptation. Adaptation to cold environments has evolved independently in different phylogenetic groups. In low temperature environments, organisms has to adapt in a complex way to be able to permanently inhabit these habitats. Since the analysis of cold adaptation in all organisms is a very complex topic, this thesis is focused on microorganisms. Within this group, it is possible to find certain, which are repeated also in unrelated taxa. The general mechanisms include changes in membrane composition, shifts of enzyme temperature optima, production of compounds that prevent the negative effects of low temperature or the formation of resting stages. This thesis summarizes the mechanisms of cold adaptation which have evolved in microorganisms as response to a long-term or temporary survival at low temperatures. Their potential biotechnological applications are also mentioned. keywords: psychrophilic, psychrotolerant, cold adaptation, enzymes,...
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Energy metabolism and apoptotsis markers in cold heart aclimated rat.
Pospíšilová, Barbora ; Horníková, Daniela (advisor) ; Knytl, Martin (referee)
Cold adaptation and her effects has been known for many decates. Positive or negative impact depends especially on its length and strength. The lower temperature can very often cause the stress for organism. On the other hand in expreriment with long-term adapatation were found positive consequences on cardiovascular system. We found the lack of studies devoted to the energy metabolism and apoptosis in heart tissue during long-term cold adaptation. In this work we used a model with milder conditions of the adaptation (10žC±1), so there wouldn't be damage of the experimental animals. We compared the resuls betwen control, cold and regressive group of rats. In this expreriment we used methods of electrophoresis and Western blot. The target of the work was found if we can find any differences betwen chosen HIF targeted genes. The next goal was to detect the differences betwen chosen pro-apoptotic and anti-apoptotic markers. Keywords: cold adaptation, heart, energetic metabolism, HIF, apoptosis
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The role of the adrenergic system in the process of cold acclimation
Dynybylová, Anna ; Novotný, Jiří (advisor) ; Brabcová, Iveta (referee)
The ability to keep constant body temperature is necessary for mammals. There are effective strategies developed during the evolution - shivering and nonshivering thermogenesis, which start during cold exposure. This thesis is focused on the nonshivering thermogenesis which occurs in brown adipose tissue and is controlled by norepinephrine released from the sympathetic nerves if the cold stress persists for a long time. The principle of the heat production is based on function of the uncoupling protein 1 which disrupts the proton gradient in mitochondria thereby releasing heat the waste product. Similar mechanism of energy dissipation is used not only during cold exposure but also after digestion of high fat diet, which may provide clues for potential therapeutic treatment of obesity and associated metabolic diseases. This study summarizes current knowledge about the role of adrenergic signalling in the process of cold acclimation. Key words: cold acclimation, nonshivering thermogenesis, brown adipose tissue, sympathetic nerve system, uncoupling protein 1 (UCP1), obesity
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The role of beta1 adrenergic receptors in heart of cold acclimated rat
Liptáková, Andrea ; Žurmanová, Jitka (advisor) ; Nováková, Olga (referee)
During cold acclimation the heat production is shifted from shivering to non-shivering thermogenesis, which is mediated by adrenergic signaling. It has also been observed, that cold acclimation may increase the organismal resistence to pathological stimuli and may affect functional parameters of cardiovascular system. However, acute exposure to sever cold is often associated with detrimental effects on the body. We have recently shown that chronic exposure to cold increases the heart's resistance to ischemia-reperfusion injury without negative side effects when mild temperatures are used, however the mechanism of protection is not yet known. The aim of this work was to determine whether: i) if the sensitivity of the heart to ischemia changes already after the first day of cold exposure and does not show any negative effects, ii) if β1-adrenergic signaling plays a role in chronic regimen of cold-induced cardioprotection. The results of this work showed that i) one day of exposure to mild cold did not change the sensitivity of the heart to ischemia and ii) metoprolol treatment reduced the infarct size in the control group, but did not affect the heart of cold-adapted rats. Key words : Heart, rat, beta 1 adrenergic receptors, cold acclimation
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The role of cold acclimation in activation of adrenegic and thyrode signalling pathway in rat myocardium
Tibenská, Veronika ; Žurmanová, Jitka (advisor) ; Babula, Petr (referee) ; Tribulová, Narcisa (referee)
Despite advances in research and therapy, cardiovascular diseases are still the leading cause of death worldwide. A closer understanding of the endogenous protective mechanism may improve pharmacological interventions for the treatment of heart diseases. Cold acclimation or hardening has strong potential for reducing cardiovascular risk and the literature shows that it stimulates the β-adrenergic and thyroid systems in tissues. At the same time, the adrenergic system in the heart is one of the main regulators of cardiac activity. However, these signaling pathways have surprisingly not been studied at the protein level in the heart yet, and no studies can be found on the subject matter in current literature. Our results show a reduced infarct size induced by ischemic injury in cold-acclimated rats (CA) at 8 ř C for 5 weeks and then returning to normothermic conditions for 2 weeks (CAR). The aim of this dissertation is to determine, the degree of involvement of the adrenergic system in the myocardium during acclimation after 3 days, 10 days, 5 weeks of CA and subsequent CAR at the level of all three β-adrenergic receptor isoforms (β-ARs) and their signaling pathways. The results show unchanged signaling of β1-AR-Gs-adenylyl cyclase-protein kinase A in the cardioprotective regimes CA and CAR, whose...
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The effect of cold stress on the immune system in the presence of infection
Kratochvílová, Anna ; Krulová, Magdaléna (advisor) ; Filipp, Dominik (referee)
Although the relationship between the effects of cold and infection has been studied for a long time, the mechanisms contributing to this phenomenon have not yet been discovered. While short-term exposure to cold triggers a stress response and the production of proinflammatory cytokines, long-term cold exposure induces adaptation and anti- inflammatory shift. The role of cold adaptation in the development and the process of the organism's response to infection remains an unresolved issue. In this diploma thesis, we focused on determining the effect of cold stress or cold adaptation on the immune system of rats which was stimulated by ligands of Toll-like receptors (TLRs). The obtained results showed the importance of γδT lymphocytes and their cytokine production in the process of cold adaptation. To determine how cold adaptation affects the response to infectious agents, we studied changes in the proportion of different immune cell populations in rats treated with the TLR2/6 ligand Pam2CSK4. We determined significant changes in the activation of myeloid cells and B lymphocytes, but also in the population of γδT lymphocytes. Our obtained results suggested the importance of γδT lymphocytes and the protective effect of cold adaptation. Key words: immune system, cold stress, cold adaptation, infection,...
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The role of beta1 adrenergic receptors in heart of cold acclimated rat
Liptáková, Andrea ; Žurmanová, Jitka (advisor) ; Nováková, Olga (referee)
During cold acclimation the heat production is shifted from shivering to non-shivering thermogenesis, which is mediated by adrenergic signaling. It has also been observed, that cold acclimation may increase the organismal resistence to pathological stimuli and may affect functional parameters of cardiovascular system. However, acute exposure to sever cold is often associated with detrimental effects on the body. We have recently shown that chronic exposure to cold increases the heart's resistance to ischemia-reperfusion injury without negative side effects when mild temperatures are used, however the mechanism of protection is not yet known. The aim of this work was to determine whether: i) if the sensitivity of the heart to ischemia changes already after the first day of cold exposure and does not show any negative effects, ii) if β1-adrenergic signaling plays a role in chronic regimen of cold-induced cardioprotection. The results of this work showed that i) one day of exposure to mild cold did not change the sensitivity of the heart to ischemia and ii) metoprolol treatment reduced the infarct size in the control group, but did not affect the heart of cold-adapted rats. Key words : Heart, rat, beta 1 adrenergic receptors, cold acclimation
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