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Role of interaction between circadian and immune system in development of obesity and type 2 diabetes mellitus
Honzlová, Petra ; Sumová, Alena (advisor) ; Okuliarová, Monika (referee) ; Vodička, Martin (referee)
Disruptions within the circadian, metabolic, and immune systems contribute to the onset of metabolic illnesses, including type 2 diabetes. This doctoral thesis aimed to examine the mutual interactions between these three systems in relation to the development of metabolic disorders. The circadian system regulates a variety of mammalian physiological processes. On the molecular level, the circadian clock is in individual cells maintained by a complex of interconnected transcription-translation feedback loops. The circadian system is hierarchically organized, consisting of the central circadian clock residing within the suprachiasmatic nuclei (SCN) and of peripheral oscillators found in various organs and tissues, including the pancreas and compartments of the innate immune system such as macrophages and microglia. The central circadian clock synchronizes the peripheral oscillators via multiple pathways, including feeding- related metabolic changes to which some of the peripheral oscillators are highly sensitive. Misaligned feeding can thus induce dyssynchrony between individual peripheral oscillators. Our results show that a reverse restricted feeding (rRF) regimen, when food is available only for a limited time during the resting period of the day, has distinct effects on the circadian clocks in...
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Internal communication within the circadian system and its significance for our health
Honzlová, Petra ; Sumová, Alena (advisor) ; Moravcová, Simona (referee)
Mammalian circadian cycle is generated by hierarchically organized system of internal rhythmical oscillations in clock gene expression (Clock, Bmal1, Per, Cry, Rev-Erb, etc.) which take place in nearly all living cells in our body. The master pacemaker is located in suprachiasmatic nucleus (SCN) in hypothalamus. According to its synchronization to photic and non-photic external stimuli SCN generates signal for entrainment of peripheral clock. Peripheral clock synchronization is maintained via neuronal or hormonal (glucocorticoids, melatonin) pathways, regulation of body temperature or food intake and affects various physiological processes. Desynchronization of central and peripheral clock can be the cause or the manifestation of impaired health condition. Powered by TCPDF (www.tcpdf.org)
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The Circadian System and Sleep in Individuals with ADHD
Nejedlý, Martin ; Skálová, Kateřina (advisor) ; Honzlová, Petra (referee)
Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with sleep disorders and abnormalities of the circadian system. In recent studies, ADHD has been linked to late chronotype and delayed sleep phase disorder, clock gene polymorphisms, geographic variation in solar irradiation, longer sleep latency, and impaired sleep quality. However, research findings in children with ADHD often differ from those in adult patients. A new diagnostic category, ADHD-SOM, has been proposed to describe individuals whose symptoms are partially caused by chronic sleep issues. However, most of the evidence is correlational. The thesis summarizes research on sleep and circadian correlates of ADHD and some of the potential mechanisms explaining these associations. Chronotherapy and sleep interventions are promising methods of adjunctive ADHD treatment.
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Circadian sleep regulation and sleep deprivation
Zeithamlová, Barbora ; Weissová, Kamila (advisor) ; Honzlová, Petra (referee)
The circadian system is designed to generate circadian rhythms and serve as the human inner clock. This is achieved through the molecular mechanism of autonomous transcriptional-translational feedback loops, in which so-called clock genes are involved. Circadian rhythms regulate the timing of physiological and behavioral processes, including sleep. Sleep is important for the proper functioning of the human organism. As a result of desynchronization of circadian rhythm, disturbances of sleep arise which threaten the mental and physical state of man. One of the examples is sleep deprivation which is deffined as a lack of necessary amount of sleep. Besides its negative effect on human health, there had been also reported positive effect in the treatment of symptoms in patients with unipolar depression. Other studies suggest that deprivation causes a reset of the circadian system, correcting the abnormal functioning of the internal clock. These effects have only a short duration, but it appears that they could be stabilized by combining sleep deprivation therapy with other therapeutic approaches. However, it is crucial to understand the exact mechanism that causes the positive effect in sleep deprivation therapy.
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Consequences of desynchronization of the circadian system by constant light
Petrželková, Lucie ; Bendová, Zdeňka (advisor) ; Honzlová, Petra (referee)
The circadian clock exists in every organism and their period is approximately 24 hours. This circadian rhythm is maintained even in a completely non-periodic environment but must be adapted to a precise 24-hour solar cycle using a synchronizer, called zeitgeber. The main controlling organ of the circadian rhythm are the suprachiasmatic nuclei (SCN) in the ventral hypothalamus. There are also peripheral clocks, for example in the liver or lungs. These peripheral clocks operate autonomously but the SCNs synchronize them with their own period and phase. The most important zeitgeber is the light and dark alternation. This bachelor thesis describes the consequences of conditions where there is no regular light and dark alternation and constant light conditions are established instead. Constant light can disturb the circadian rhythm and desynchronize the circadian clocks. This bachelor thesis summarizes the scientific knowledge of desynchronization by the effect of constant light and briefly describes the selected pathologies resulting from the desynchronization of the circadian system. Selected pathologies include ovarian tumour and breast cancer, obesity and insulin resistance, immunosenescense and schizophrenia. Key words constant light, circadian system, suprachiasmatic nucleus
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Interaction between circadian clock and macrophages in the adipose tissue
Honzlová, Petra ; Sumová, Alena (advisor) ; Horáková, Olga (referee)
Well functioning circadian system is crucial component of healthy organism and its disruption can result in impairment of metabolic functions with consequential development of obesity and type 2 diabetes mellitus. Obesity is in general caused by enhanced migration of pro- inflammatory polarized macrophages (M1) into adipose tissue. We have shown, that interaction of this type of macrophages with adipose tissue had significant effect on rhythmic expression of clock genes in adipocytes. We further investigated effect of high fat diet and diet enriched by omega-3 fatty acids on circadian oscillations in WAT and differently polarized macrophages. This diet affected oscillations in adipose tissue and in M0 and M2 polarized macrophages. These results support previous findings of effect of omega-3 fatty acids on metabolism and suggest their effect on circadian system as well. Key words: circadian rhythms, adipose tissue, macrophages, omega-3 fatty acids, high fat diet
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Internal communication within the circadian system and its significance for our health
Honzlová, Petra ; Sumová, Alena (advisor) ; Moravcová, Simona (referee)
Mammalian circadian cycle is generated by hierarchically organized system of internal rhythmical oscillations in clock gene expression (Clock, Bmal1, Per, Cry, Rev-Erb, etc.) which take place in nearly all living cells in our body. The master pacemaker is located in suprachiasmatic nucleus (SCN) in hypothalamus. According to its synchronization to photic and non-photic external stimuli SCN generates signal for entrainment of peripheral clock. Peripheral clock synchronization is maintained via neuronal or hormonal (glucocorticoids, melatonin) pathways, regulation of body temperature or food intake and affects various physiological processes. Desynchronization of central and peripheral clock can be the cause or the manifestation of impaired health condition. Powered by TCPDF (www.tcpdf.org)
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