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Circadian disruption

Melissa A Wren-Dail, Robert T Dauchy, Tara G Ooms, Kate C Baker, David E Blask, Steven M Hill, Lynell M Dupepe, Rudolf P Bohm
Environmental enrichment (EE) gives laboratory animals opportunities to engage in species-specific behaviors. However, the effects of EE devices on normal physiology and scientific outcomes must be evaluated. We hypothesized that the spectral transmittance (color) of light to which rats are exposed when inside colored enrichment devices (CED) affects the circadian rhythms of various plasma markers. Pair-housed male Crl:SD rats were maintained in ventilated racks under a 12:12-h light:dark environment (265.0 lx; lights on, 0600); room lighting intensity and schedule remained constant throughout the study...
2016: Comparative Medicine
Clara Bien Peek, Daniel C Levine, Jonathan Cedernaes, Akihiko Taguchi, Yumiko Kobayashi, Stacy J Tsai, Nicolle A Bonar, Maureen R McNulty, Kathryn Moynihan Ramsey, Joseph Bass
Circadian clocks are encoded by a transcription-translation feedback loop that aligns energetic processes with the solar cycle. We show that genetic disruption of the clock activator BMAL1 in skeletal myotubes and fibroblasts increased levels of the hypoxia-inducible factor 1α (HIF1α) under hypoxic conditions. Bmal1(-/-) myotubes displayed reduced anaerobic glycolysis, mitochondrial respiration with glycolytic fuel, and transcription of HIF1α targets Phd3, Vegfa, Mct4, Pk-m, and Ldha, whereas abrogation of the clock repressors CRY1/2 stabilized HIF1α in response to hypoxia...
October 19, 2016: Cell Metabolism
Gregory D M Potter, Debra J Skene, Josephine Arendt, Janet E Cade, Peter J Grant, Laura J Hardie
Circadian (∼ 24 hour) timing systems pervade all kingdoms of life, and temporally optimize behaviour and physiology in humans. Relatively recent changes to our environments, such as the introduction of artificial lighting, can disorganize the circadian system, from the level of the molecular clocks that regulate the timing of cellular activities to the level of synchronization between our daily cycles of behaviour and the solar day. Sleep/wake cycles are intertwined with the circadian system, and global trends indicate that these too are increasingly subject to disruption...
October 20, 2016: Endocrine Reviews
Aurore Woller, Hélène Duez, Bart Staels, Marc Lefranc
To maintain energy homeostasis despite variable energy supply and consumption along the diurnal cycle, the liver relies on a circadian clock synchronized to food timing. Perturbed feeding and fasting cycles have been associated with clock disruption and metabolic diseases; however, the mechanisms are unclear. To address this question, we have constructed a mathematical model of the mammalian circadian clock, incorporating the metabolic sensors SIRT1 and AMPK. The clock response to various temporal patterns of AMPK activation was simulated numerically, mimicking the effects of a normal diet, fasting, and a high-fat diet...
October 18, 2016: Cell Reports
Ruth C Travis, Angela Balkwill, Georgina K Fensom, Paul N Appleby, Gillian K Reeves, Xiao-Si Wang, Andrew W Roddam, Toral Gathani, Richard Peto, Jane Green, Timothy J Key, Valerie Beral
BACKGROUND: It has been proposed that night shift work could increase breast cancer incidence. A 2007 World Health Organization review concluded, mainly from animal evidence, that shift work involving circadian disruption is probably carcinogenic to humans. We therefore aimed to generate prospective epidemiological evidence on night shift work and breast cancer incidence. METHODS: Overall, 522 246 Million Women Study, 22 559 EPIC-Oxford, and 251 045 UK Biobank participants answered questions on shift work and were followed for incident cancer...
December 2016: Journal of the National Cancer Institute
Eunjoo Cho, Euna Lee, Eun Young Kim
The circadian clock system enables organisms to anticipate the rhythmic environmental changes and to manifest behavior and physiology at advantageous times of day. Transcriptional/translational feedback loop (TTFL) is the basic feature of eukaryotic circadian clock and is based on the rhythmic association of circadian transcriptional activator and repressor. In Drosophila, repression of dCLOCK/CYCLE (dCLK/CYC) mediated transcription by PERIOD (PER) is critical for inducing circadian rhythms of gene expression...
October 19, 2016: BMB Reports
Huan Wang, Hui Chen
OBJECTIVE: Circadian rhythm disruption is shown to be the cause of various health disorders. CLOCK and BMAL1, two core circadian transcription factors, were associated with the regulation of glucose homeostasis. This study evaluated the association between single nucleotide polymorphisms in CLOCK and BMAL1 gene and insulin resistance (IR) in hypertensive patients. DESIGN AND METHOD: We collected 334 outpatients with essential hypertension (EH), who have not taken any antihypertensive agents or stopped the medications for at least a week for this case-control study...
September 2016: Journal of Hypertension
Asadur Rahman, Yui Takeshige, Yoshihide Fujisawa, Hirofumi Hitomi, Daisuke Nakano, Akira Nishiyama
OBJECTIVE: Disrupted circadian rhythm of blood pressure is associated with cardiovascular events in metabolic syndrome and obesity. Experiments were conducted to examine the effects of sodium-glucose co-transporter 2 (SGLT2) inhibitors on circadian rhythm of blood pressure in a genetic model of obese metabolic syndrome (SHR/NDmcr-cp (+/+) (SHRcp)) and salt-treated obese Otsuka Long Evans Tokushima Fatty (OLETF) rats. DESIGN AND METHOD: Luseogliflozin (10 mg/kg/day, p...
September 2016: Journal of Hypertension
L Müller, D Weinert
In a natural environment, social abilities of an animal are important for its survival. Particularly, it must recognize its own social rank and the social rank of a conspecific and have a good social memory. While the role of the circadian system for object and spatial recognition and memory is well known, the impact of the social rank and circadian disruptions on social recognition and memory were not investigated so far. In the present study, individual recognition of social rank and social memory performance of Djungarian hamsters revealing different circadian phenotypes were investigated...
October 13, 2016: Behavioural Processes
Karen Spruyt, Wiebe Braam, Marcel Smits, Leopold Mg Curfs
AIMS: Individuals with Smith-Magenis syndrome (SMS) are reported to have a disrupted circadian rhythm. Our aim was to examine problematic sleeping in those attending our sleep clinic for the first time. METHODS: At intake, caregivers of 50 children and nine adults with SMS were surveyed about the sleep pattern and potential melatonin administration. Sampling of salivary melatonin levels was performed. RESULTS: At intake, exogenous melatonin was used by 16 children (27...
October 14, 2016: CNS Neuroscience & Therapeutics
Valeriy A Poroyko, Alba Carreras, Abdelnaby Khalyfa, Ahamed A Khalyfa, Vanessa Leone, Eduard Peris, Isaac Almendros, Alex Gileles-Hillel, Zhuanhong Qiao, Nathaniel Hubert, Ramon Farré, Eugene B Chang, David Gozal
Chronic sleep fragmentation (SF) commonly occurs in human populations, and although it does not involve circadian shifts or sleep deprivation, it markedly alters feeding behaviors ultimately promoting obesity and insulin resistance. These symptoms are known to be related to the host gut microbiota. Mice were exposed to SF for 4 weeks and then allowed to recover for 2 weeks. Taxonomic profiles of fecal microbiota were obtained prospectively, and conventionalization experiments were performed in germ-free mice...
October 14, 2016: Scientific Reports
Amandine Chaix, Amir Zarrinpar, Satchidananda Panda
Circadian clocks are cell-autonomous timing mechanisms that organize cell functions in a 24-h periodicity. In mammals, the main circadian oscillator consists of transcription-translation feedback loops composed of transcriptional regulators, enzymes, and scaffolds that generate and sustain daily oscillations of their own transcript and protein levels. The clock components and their targets impart rhythmic functions to many gene products through transcriptional, posttranscriptional, translational, and posttranslational mechanisms...
October 10, 2016: Journal of Cell Biology
Lone Baandrup, Ole Bernt Fasmer, Birte Yding Glenthøj, Poul Jørgen Jennum
BACKGROUND: Patients with severe mental illness often suffer from disruptions in circadian rest-activity cycles, which might partly be attributed to ongoing psychopharmacological medication. Benzodiazepines are frequently prescribed for prolonged periods despite recommendations of only short-term usage. Melatonin, a naturally occurring nocturnal hormone, has the potential to stabilize disrupted circadian rhythmicity. Our aim was to investigate how prolonged-release melatonin affects rest-activity patterns in medicated patients with severe mental illness and if benzodiazepine dose reduction is associated with changes in circadian rhythm parameters...
October 13, 2016: BMC Psychiatry
Barbra A Dickerman, Sarah C Markt, Markku Koskenvuo, Christer Hublin, Eero Pukkala, Lorelei A Mucci, Jaakko Kaprio
PURPOSE: Sleep disruption and shift work have been associated with cancer risk, but epidemiologic evidence for prostate cancer remains limited. We aimed to prospectively investigate the association between midlife sleep- and circadian-related parameters and later prostate cancer risk and mortality in a population-based cohort of Finnish twins. METHODS: Data were drawn from the Older Finnish Twin Cohort and included 11,370 twins followed from 1981 to 2012. Over the study period, 602 incident cases of prostate cancer and 110 deaths from prostate cancer occurred...
October 12, 2016: Cancer Causes & Control: CCC
Cinthia García-Luna, Paulina Soberanes-Chavez, Patricia de Gortari
Feeding patterns are important factors in obesity evolvement. Time-restricted feeding schedules (tRF) during resting phase change energy homeostasis regulation, disrupting the circadian release of metabolism-regulating hormones, such as leptin, insulin and corticosterone and promoting body weight gain. Thyroid (HPT) and adrenal (HPA) axes exhibit a circadian regulation and are involved in energy expenditure, thus studying their parameters in tRF paradigms will elucidate their role in energy homeostasis impairments under such conditions...
October 11, 2016: Journal of Endocrinology
Zsolt Nagy, Alexa Marta, Henriett Butz, Istvan Liko, Karoly Racz, Attila Patocs
Peripheral clocks are set by different nervous, hormonal and metabolic stimuli, and regulate the circadian expression of several genes. We investigated whether a peripheral clock could be induced in the human adrenocortical cell line H295R and whether glucocorticoid receptor isoforms (GRα and GRß) are involved in this clock system. After synchronization of cells with serum shock, the rhythmic oscillation of clock genes PER1, PER2, REV-ERBα, and ARNTL was confirmed. In addition, H295R cells even without serum shock showed rhythmic expression of PER1, PER2, CRY1 and ARNTL...
October 7, 2016: Steroids
Andrew Korenevsky, Yulia Milyutina, Ljudmila Kozina, Alexander Arutjunyan
Industrial xenobitics, as well as endogenous damaging factors, such as L-homocysteine, are a well-known source of reactive oxygen species that disrupt biological processes. Among many others, luteinizing hormone releasing hormone synthesis and secretion mediated by a variety of neurotransmitters, which are under control of the hypothalamus and pineal gland, may be put in peril by reactive oxygen species. Their formation can be one of the reasons for the reproductive function shutdown in ageing as the generic response to the damaging factors independent of their nature...
October 6, 2016: Current Aging Science
Thaíse Campos Mondin, Taiane de Azevedo Cardoso, Luciano Dias de Mattos Souza, Karen Jansen, Pedro Vieira da Silva Magalhães, Flávio Kapczinski, Ricardo Azevedo da Silva
BACKGROUND: It is known that sleep disturbance has been considered a trait-marker of mood disorders. However, the role of disruptions in biological rhythms, such as eating, activity, and social patterns, needs to be better understood. AIM: To assess the differences in biological rhythms in subjects with bipolar disorder, major depressive disorder, and healthy controls. We also tested the association between disruptions of biological rhythms and circadian preferences...
September 30, 2016: Journal of Psychiatric Research
Lonnele J Ball, Oxana Palesh, Lance J Kriegsfeld
Most physiological processes in the brain and body exhibit daily (circadian) rhythms coordinated by an endogenous master clock located in the suprachiasmatic nucleus of the hypothalamus that are essential for normal health and functioning. Exposure to sunlight during the day and darkness at night optimally entrains biological rhythms to promote homeostasis and human health. Unfortunately, a major consequence of the modern lifestyle is increased exposure to sun-free environments during the day and artificial lighting at night...
October 2016: Endocrine Reviews
Erica L Schoeller, Daniel D Clark, Sandeepa Dey, Nathan V Cao, Sheila J Semaan, Ling W Chao, Alexander S Kauffman, Lisa Stowers, Pamela L Mellon
Circadian rhythms synchronize physiological processes with the light-dark cycle and are regulated by a hierarchical system initiated in the suprachiasmatic nucleus (SCN), a hypothalamic region that receives direct photic input. The SCN then entrains additional oscillators in the periphery. Circadian rhythms are maintained by a molecular transcriptional feedback loop, of which BMAL1 is a key member. Disruption of circadian rhythms by deletion of the BMAL1 gene (Bmal1 KO) induces a variety of disease states, including infertility in males, due to unidentified mechanisms...
October 5, 2016: Endocrinology
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