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Mechanisms of muscle non-shivering thermogenesis
Vávrová, Anna ; Bardová, Kristina (advisor) ; Galatík, František (referee)
The capacity to regulate body temperature is of great importance for the survival and evolution of organisms. Endotherms possess highly efficient mechanisms for generating heat, including muscle shivering and non-shivering thermogenesis (NST), which occurs predominantly in brown adipose tissue and muscle. The process of muscle NST is a complex one, involving multiple mechanisms. However, it seems likely that the effect of sarcolipin on SERCA protein plays a key role. This occurs when ATP cleavage occurs without Ca2+ pumping into the sarcoendoplasmic reticulum, accompanied by heat generation. Other key proteins of the muscle NST include ryanodine receptors, which regulate calcium concentrations, and phospholamban, which regulates SERCA activity. Mitochondrial activity also plays a crucial role in this process. The ability of muscle NST depends on the ontogenetic stage of the organism and the external conditions to which it is exposed. In addition to thermal homeostasis, these mechanisms also have a major impact on the regulation of whole-body metabolism and may serve as protection against diet-induced obesity. As with other thermogenic mechanisms, muscle NST is an energy-intensive process. Consequently, an understanding of its processes and the ability to regulate them could provide a new avenue in...
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Brown adipose tissue and its positive effects
Máchová, Magdaléna ; Horníková, Daniela (advisor) ; Haasová, Eliška (referee)
Brown adipose tissue (BAT) is a specialized type of adipose tissue that plays an important role in non-shivering thermogenesis which is induced most often after cold acclimation. However, many studies have also highlighted the role of BAT in influencing the cardiovascular system and thus obesity, diabetes mellitus type 2, atherosclerosis, and insulin resistance. BAT has a protective effect against oxidative stress and recent studies suggest that it also has a potential therapeutic relevance for the treatment of cancer and osteoporosis, while it may also play a role in the body's immunomodulatory effects. Key words: brown adipose tissue, non-shivering thermogenesis, cold acclimation, β-adrenergic receptors, therapeutic potential
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Effect of cold on humans from the perspective of physiology and ecology
Chvojková, Anna ; Hora, Martin (advisor) ; Oplt, Pavla Alexia (referee)
This bachelor thesis deals with the issue of cold and its effect on humans. The aim of the thesis is to compare how much different factors such as body proportions, amount of brown adipose tissue (BAT), age or sex influence the physiological response to cold. According to the available literature, the physiological response to cold is mainly dependent on body proportions and the amount of BAT, while factors such as age and sex are not as significantly reflected in the response. The second aim is to inspect whether ecogeographic rules also apply to human populations with a special focus on one Arctic population - the European Sami. Sami have, as predicted by ecogeographic rules, a broad trunk and short limbs, which limits heat loss. The last goal of the thesis is to clarify the possible use of cold exposure in healthcare and sports physiotherapy. Cold therapy could help with the treatment of inflammatory diseases, obesity, depression, or muscle recovery. However, further application of cold therapy in medical practice requires a thorough study of the mechanisms by which cold affects specific diseases and the definition of optimal conditions under which cold therapy is effective.
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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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