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Mechanism of cardioprotection elicited by cold acclimation
Csomová, Martina ; Žurmanová, Jitka (advisor) ; Holzerová, Kristýna (referee)
Myocardial infarction is the most common cause of death and disability worldwide. The term myocardial infarction refers to the death of cardiac cells, cardiomyocytes, caused by ischaemia resulting from a perfusion imbalance between the supply and demand for oxygen and nutrients. Recently, cold acclimatization has been found to reduce infarct size after ischemia/reperfusion (I/R) injury, but the mechanism is not fully clarified. Cold acclimatization elicits a thermoregulatory response by activating nontalamic thymogenesis associated with brown adipose tissue (BAT) activation. Cold-stimulated adrenergic signaling increases the expression of mitochondrial uncoupling protein 1 (UCP1), a key factor for heat production. Activated BAT increases metabolic turnover and thus likely contributes to the protection of the heart from myocardial infarction. In this work, I simulate I/R injury by establishing a hypoxic- reoxygenation (H/R) protocol in isolated adult cardiomyocytes. The aim of this work was to introduce different approaches to assess the viability of isolated cardiomyocytes and compare their utility, to investigate the effect of different cold adaptations on cardiomyocyte viability during the H/R protocol using the Cytation 5 multidetector, and subsequently to determine the effect of inhibitors of...
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Characterization of epicardial, pericardial, and perivascular adipose tissue in humans and mice
Rybová, Aneta ; Bardová, Kristina (advisor) ; Kuneš, Jaroslav (referee)
Heart-associated adipose tissue plays an important role in the physiology of the cardiovascular system. Not only does it serve as a protection against mechanical and thermal stress, but it also provides energy for the cardiomyocytes. On the other hand, it can also act as a tissue that promotes a proinflammatory state around the heart, which can result in the development of cardiovascular diseases. Information from the study of epicardial, perivascular or paracardial and other adipose tissue surrounding the heart and large vessels may be used in the prevention of pathological conditions of the heart that are associated with the presence of this adipose tissue.
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An effect of cold showers on physical characteristics of adults
ANDERLOVÁ, Štěpánka
The bachelor thesis is focused on the behavior of brown adipose tissue (BAT) when activated by cold exposure. Non-shaking thermogenesis then takes place in this tissue, during which heat is generated. For this reason, it is possible to activate BAT with a cold shower, during which a given thermogenesis takes place, and to monitor the impact on the change in the physical charakteristics of an adult. The cold showers research involved 48 students aged 19-26 who took a shower with cold water several times a week. One group was taking cold showers for 11 months, the other for three months. Their body composition was measured with a Bodystat device and skin folds was measured at four parts of the body using a caliper, always at the beginning and at the end of the research. The measured data were processed and evaluated. An important result can be found in experimental groups, where with increasing number of cold showers there was an increase in adipose tissue, even though the result is not statistically significant.
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Utilization of energy substrates in white and brown adipose tissue in metabolic syndrome
Seďová, Karolína ; Škop, Vojtěch (advisor) ; Šilhavý, Jan (referee)
1 Abstrakt Hnědá tuková tkáň je unikátní termoregulační orgán, její funkcí je přeměňovat energii ve formě protonového gradientu na energii tepelnou a zároveň snižovat efektivitu metabolismu. Její funkce se zdá být nadějí v léčbě metabolického syndromu a komplikací s ním spojených. Efekt hnědé tukové tkáně v léčbě MS však stále není objasněn a proto jsme chirurgicky odstranili tuto tkáň u potkanů, kteří trpí metabolickým syndromem, abychom objasnili důsledky extirpace na parametry metabolického syndromu. V této práci jsme sledovali aktivitu interskapulární tukové tkáně na parametry metabolického syndromu. Srovnávali jsme parametry mezi kmeny HHTg potkanů a kontrolním kmenem potkanů Wistar a pozorovali jsme nižší hmotnost potkanů kmene HHTg přes projevy ostatních parametrů metabolického syndromu, jako je dyslipidémie, inzulinová rezistence tukové tkáně, vyšší hodnoty NEMK v krvi. Zjistili jsme, že tito potkani mají významně vyšší aktivitu iBAT, jak v inkorporaci palmitátu do lipidů, tak ve spalování lipidů ve formě CO2 a zejména v nižším věku. Tato zjištění nás vedla k hypotéze, že iBAT by mohla mít zásadní vliv na parametry MS u neobézních potkanů. Extirpací iBAT u mladých potkanů, ani u potkanů v pokročilejším věku však neměla zásadní vliv na metabolismus ani na hmotnost. Dokonce došlo ke zlepšení některých...
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Importance of adipose tissue metabolism for whole-body energy balance
Zouhar, Petr ; Flachs, Pavel (advisor) ; Rossmeislová, Lenka (referee) ; Kazdová, Ludmila (referee)
Adipose tissue plays a crucial role in nutrient and energy homeostasis. At the time of worldwide pandemy of obesity and consequent metabolic syndrome, a great effort is made to find new treatments with potential to preserve insulin sensitivity, or even counteract development of obesity and type 2 diabetes. There are three principal possibilities how the adipose tissue biology can contribute to this goal: 1) induction of UCP1-dependent energy dissipation in brown adipose tissue; 2) conversion of white adipose depots to brown-like tissue (i.e. "browning"); and 3) stimulation of UCP1-independent thermogenesis in white adipose tissue. This thesis is based on two published works and one article under preparation. Generaly, it is focused on three different approaches targeting the above mentioned processes in adipose tissue of laboratory mouse: 1) diet supplementation with bile acids; 2) combination treatment of ω-3 polyunsaturated fatty acids and calorie restriction; and 3) cold exposure. In the experiments with administration of bile (specifically chenodeoxycholic) acid to mice, we confirm specific induction of UCP1 in both brown and subcutaneous white adipose tissue, as well as reversion of obesity in the response to the treatment. Nevertheless, most of the acute beneficial effects are mediated by...
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Mitochondrial respiration of brown adipose tissue in development of cold acclimation
Galatík, František ; Žurmanová, Jitka (advisor) ; Holzerová, Kristýna (referee)
Historical experiments regarding the influence of low ambient temperatures were often accompanied with the development of detrimental effects. Our laboratory recently published a protocol of mild cold acclimation (5 weeks in 8 ± 1 řC) which induces cardioprotective phenotype in rats (Rattus norvegicus). An important mechanism of cold acclimation is the activation and increase of brown adipose tissue. Besides the nonshivering thermogenesis brown adipose tissue can produce a multitude of autocrine, paracrine, and endocrine factors which might positively influence whole-body metabolism and function of other important organs. The effect of cold acclimation on brown adipose tissue is not however explored very well. The aim of this work was to asses selected parameters of respiration of isolated brown adipose tissue mitochondria of control rats living in 24 ± 1 řC and compare it with that of rats exposed to 8 ± 1 řC for 1 day, 3 days, 10 days, and 5 weeks. Results of this works were 1) the increase in respiration occurs after the 1-day cold exposure and 2) the highest respiration per 1 mg of mitochondrial protein appears to be after the 10 days of cold exposure. Key-words: Brown adipose tissue, mitochondria, respiration, cold acclimation
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The role adipose tissue in development of insulin resistance and other metabolic disorders in patients with pheochromocytoma
Klímová, Judita ; Petrák, Ondřej (advisor) ; Kříž, Jan (referee) ; Mlíková Seidlerová, Jitka (referee)
Pheochromocytoma and functional paraganglioma (PPGL) are rare neuroendocrine tumors characterized by catecholamines overproduction, which give a rise to disorders of glucose, lipid, and energy metabolism. The role of adipose tissue in these processes remains unclear. Our aim was to determine the gene expression profile in subcutaneous and visceral adipose tissue of patients with PPGL focusing on endocrine functions of adipose tissue, occurrence of brown (BAT) and beige adipose tissue (BeAT), all in connection with other measured metabolic and energy parameters and levels of circulating adipokines. We demonstrate signs of UCP1-dependent norepinephrine induced thermogenesis connected with overexpression of DIO2 in retroperitoneal VAT of PPGL and higher expression of key transcriptional factors of brown/beige adipogenesis, namely PPARGC1α, CEBPB and PRDM16. However, classic murine BAT or BeAT gene signature in VAT of PPGL was not detected. In subcutaneous adipose tissue (SAT) of PPGL we found signs of possible BeAT transformation, however without simultaneously undergoing UCP1-dependent thermogenesis. We also demonstrate that patients with PPGL have higher serum levels of FGF21 compared to healthy controls and these levels do not differ from obese patients. Furthermore, successful tumor removal...
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Non-shivering thermogenesis - UCP1 and other alternative mechanisms
Kružíková, Nikola ; Zouhar, Petr (advisor) ; Tauchmannová, Kateřina (referee)
Adaptive thermogenesis is a natural mechanism by which endothermic organisms increase their basal metabolic rate to maintain stable body temperature. During acute exposure to subthermoneutral temperatures, the first reaction of organism is shivering which is gradually replaced by nonshivering thermogenesis. Nonshivering thermogenesis in mammals is associated with a UCP1 protein located in the inner mitochondrial membrane in adipose cells. In active mode, UCP1 uncouples respiratory chain from ATP synthesis and by that significantly increases metabolic rate. Apart from UCP1, some alternative mechanisms of nonshivering thermogenesis were suggested - namely: sarcolipin uncoupling ATP hydrolysis from pumping calcium ions through SERCA pump in skeletal muscle, phosphocreatine hydrolysis in adipose tissue or futile cycling of triacylglycerols and fatty acids reesterification. However, to date, there is rather indirect and not generally accepted evidence that these mechanisms contribute significantly to adaptive nonshivering thermogenesis. Better understanding of the nonshivering thermogenesis processes would be of great clinical importance as it could allow identification of potential targets for pharmacological manipulation of energy expenditure and thus provide novel methods for reducing obesity and...
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Maturation of brown adipose tissue
Csomová, Martina ; Žurmanová, Jitka (advisor) ; Mančíková, Andrea (referee)
Brown adipose tissue (BAT) is activated under the influence of the adrenergic system and thyroid hormones in response to a cold stimulus. It's main task is to cover the body heat loss and maintain the stability of the internal environment . BAT is in most cases found in new-borns accounting for 5% of the whole body. Cells found in BAT contain a high number of mitochondria with high respiratory capacity but low ATP-synthase activity which allows the production of heat instead of ATP in process of glucose oxidation. The result is non-shivering thermogenesis. The task of my work is to summarize the current knowledge about the development of BAT and to point out the markers for its characterization. The work will also include differences in adipose tissue maturation in selected model organisms. Key words: brown adipose tissue, white adipose tissue, beige adipose tissue, non-shivering thermogenesis, uncoupling protein 1
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Thyroid hormones, their importance and exposure to cold
Špínová, Šárka ; Žurmanová, Jitka (advisor) ; Krulová, Magdaléna (referee)
Thyroid hormones are essential mainly for prenatal development and they maintain the homeostasis of many organs and body processes in adulthood. Therefore, the correct function of the regulatory axis between the hypothalamus, pituitary gland and thyroid gland is very important. Lack of these hormones is manifested, for example, by the formation of goiter, cretenism and bradycardia, excess in weight loss, ophthalmopathy, excessive sweating, tachycardia and also goiter formation. A serious problem is also the mutation of thyroid hormone receptors in target tissues. It causes nervous system disorders, hearing, vision, digestive system, incorrect cardiac function, delayed growth and mental development. Thyroid hormones are essential for the formation and activation of brown adipose tissue. This, together with the shivering thermogenesis of skeletal muscle, is involved in facultative thermogenesis, helping homoeothermic mammals to maintain a constant body core temperature. In addition, brown adipose tissue is an important endocrine organ that secretes active substances called batokines upon cold activation. Batokines have beneficial effects in the treatment of obesity, diabetes and cardiovascular disease. So we can assume that cold adaptation could effectively help in the treatment of civilization...
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