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1.
Curr Opin Ophthalmol ; 31(6): 508-513, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33009084

RESUMO

PURPOSE OF REVIEW: The aim of this article is to summarize up-to-date research on the effects of obstructive sleep apnea (OSA) on retinal vascular conditions. RECENT FINDINGS: OSA is associated with the development of diabetic retinopathy, retinal vein occlusion, and central serous chorioretinopathy. The severity of OSA and biomarkers such as the apnea-hypopnea index (AHI) correlate with the severity of retinal disease. Dysregulation of circadian locomotor output cycles kaput (CLOCK) genes that govern circadian rhythm is associated with development of proliferative retinal disease. SUMMARY: OSA and retinal vascular disease have a high cost burden on the healthcare system. OSA creates systemic changes and hypoxic conditions that may incite or exacerbate retinal vascular diseases. Retinal changes may be the first clinical manifestation of otherwise undiagnosed OSA, so it is important to refer patients with new-onset retinal vascular disease for appropriate sleep testing.


Assuntos
Oftalmopatias/complicações , Apneia Obstrutiva do Sono , Biomarcadores , Ritmo Circadiano , Humanos , Polissonografia , Doenças Retinianas/complicações , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/etiologia , Apneia Obstrutiva do Sono/fisiopatologia
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 714-717, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018087

RESUMO

Early and noninvasive identification of heart failure progression is an important adjunct to successful and timely intervention. Severity of heart failure (HF) was assessed by Left Ventricular Ejection Fraction (LVEF). In this paper, we explore the circadian (24-hour) heart rate variability (HRV) features from ''normal" (EF >50%), "at-risk" (EF <40%), and "border-line" (40% ≤ EF ≤ 50%) patient data to determine whether HRV features can predict the stage of heart failure. All coronary artery disease (CAD) 24-hour circadian heart rate data were fitted by a cosinor analysis algorithm. Hourly HRV features from time- and frequency-domains were then extracted from all 24-hour patient data. A one-way ANOVA test was performed followed by a Tukey post-hoc multiple comparison test to investigate the differences among the three groups. The results showed a statistically significant difference between the three groups when using the normalized high frequency (HF Norm), low frequency peak (LF Peak), and the normalized very-low frequency (VLF Norm) for the 05:00-06:00 and 18:00-19:00 time periods. These results highlight a possible link between the circadian variation of sympathetic and parasympathetic nervous system activity and LVEF for CAD patients. The results could be useful in differentiating the various degrees of LVEF by using only noninvasive HRV features derived over a 24-hour period.Clinical relevance- The proposed method could be clinically useful to estimate the extent of LVEF associated with the severity of heart failure by recording the circadian variation of the heart rate in CAD patients. However, further clinical trials on a larger cohort of patients and controls are required.


Assuntos
Doença da Artéria Coronariana , Ritmo Circadiano , Frequência Cardíaca , Ventrículos do Coração , Humanos , Volume Sistólico , Função Ventricular Esquerda
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3384-3387, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018730

RESUMO

Vagus nerve stimulation (VNS) is a neurostimulation therapy for epilepsy and severe depression and has been recently shown to be effective for other conditions. Despite its demonstrated safety and efficacy, long-term and off-target effects of VNS remain to be fully determined. One of the complications reported in epilepsy is stimulation-induced sleep abnormalities. As epilepsy itself can impact sleep quality, contribution of VNS alone in such off-target effects remain mainly unknown. In this study, we analyzed data from long-term VNS experiments in rats to characterize effects of VNS on circadian rhythms derived from heart rate and heart rate variability (HRV). We have also explored possible sex differences in long-term effects of VNS on intrinsic biological rhythms. Compared with control animals, significant VNS-induced changes in circadian rhythms were observed particularly in female rats over 24h and 6h light cycles (1PM-7PM). These findings enhance our understanding of VNS contribution and biological sex role on sleep difficulties reported by using VNS therapy.


Assuntos
Epilepsia , Estimulação do Nervo Vago , Animais , Ritmo Circadiano , Epilepsia/terapia , Feminino , Frequência Cardíaca , Masculino , Ratos
4.
Rev Med Suisse ; 16(707): 1745-1747, 2020 Sep 23.
Artigo em Francês | MEDLINE | ID: mdl-32969610

RESUMO

Circadian rhythmicity generated by the biological clock structures the functioning of human beings over a period of almost 24 hours. This clock is entrained daily by internal and external cues among which light is the most powerful. Several disturbances, whether clinical or biological, observed in bipolar disorders are suggestive of a disruption of the circadian rhythm. Thus, treatments that modulate the biological clock have been developed. So far, the results of light therapy are not unanimous and invite us to better specify the treatment modalities. Dark therapy is a promising intervention that is still not much studied nowadays and therefore opens up great prospects for research in the future.


Assuntos
Transtorno Bipolar/psicologia , Escuridão , Luz , Fotoperíodo , Relógios Biológicos/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Humanos
5.
PLoS Genet ; 16(8): e1009003, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866139

RESUMO

Sensory systems rely on neuromodulators, such as serotonin, to provide flexibility for information processing as stimuli vary, such as light intensity throughout the day. Serotonergic neurons broadly innervate the optic ganglia of Drosophila melanogaster, a widely used model for studying vision. It remains unclear whether serotonin modulates the physiology of interneurons in the optic ganglia. To address this question, we first mapped the expression patterns of serotonin receptors in the visual system, focusing on a subset of cells with processes in the first optic ganglion, the lamina. Serotonin receptor expression was found in several types of columnar cells in the lamina including 5-HT2B in lamina monopolar cell L2, required for spatiotemporal luminance contrast, and both 5-HT1A and 5-HT1B in T1 cells, whose function is unknown. Subcellular mapping with GFP-tagged 5-HT2B and 5-HT1A constructs indicated that these receptors localize to layer M2 of the medulla, proximal to serotonergic boutons, suggesting that the medulla neuropil is the primary site of serotonergic regulation for these neurons. Exogenous serotonin increased basal intracellular calcium in L2 terminals in layer M2 and modestly decreased the duration of visually induced calcium transients in L2 neurons following repeated dark flashes, but otherwise did not alter the calcium transients. Flies without functional 5-HT2B failed to show an increase in basal calcium in response to serotonin. 5-HT2B mutants also failed to show a change in amplitude in their response to repeated light flashes but other calcium transient parameters were relatively unaffected. While we did not detect serotonin receptor expression in L1 neurons, they, like L2, underwent serotonin-induced changes in basal calcium, presumably via interactions with other cells. These data demonstrate that serotonin modulates the physiology of interneurons involved in early visual processing in Drosophila.


Assuntos
Receptor 5-HT1B de Serotonina/genética , Receptores 5-HT1 de Serotonina/genética , Receptores 5-HT2 de Serotonina/genética , Neurônios Serotoninérgicos/metabolismo , Serotonina/metabolismo , Animais , Ritmo Circadiano/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Regulação da Expressão Gênica/genética , Interneurônios/metabolismo , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Neurotransmissores/genética , Receptores de Serotonina/genética , Serotonina/genética , Percepção Visual/genética
6.
Artigo em Russo | MEDLINE | ID: mdl-32929935

RESUMO

An important problem of modern fabrication is the lowered labor productivity and occupational safety due to fatigue. In many cases, it is the result of sleep deprivation, circadian rhythm disruption or the type of the procedures. The effective way to restore fatigue-induced functionality is a short-term daytime sleep. The term «power nap¼ has been introduced to emphasize its positive effect on some cognitive functions. This review considers the effects of short-term daytime sleep of various duration on memory consolidation. Short-term daytime sleep for up to 30 minutes between 1 p.m and 3 p.m can be recommended to improve the effectiveness of the intellectual work. These measures are intended to improve declarative memory without subsequent sleep inertia.


Assuntos
Consolidação da Memória , Ritmo Circadiano , Humanos , Memória , Sono , Privação do Sono
7.
Cochrane Database Syst Rev ; 9: CD010054, 2020 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-32888198

RESUMO

BACKGROUND: Beta-blockers are commonly used in the treatment of hypertension. We do not know whether the blood pressure (BP) lowering efficacy of beta-blockers varies across the day. This review focuses on the subclass of beta-blockers with partial agonist activity (BBPAA). OBJECTIVES: To assess the degree of variation in hourly BP lowering efficacy of BBPAA over a 24-hour period in adults with essential hypertension. SEARCH METHODS: The Cochrane Hypertension Information Specialist searched the following databases for relevant studies up to June 2020: the Cochrane Hypertension Specialised Register; CENTRAL; 2020, Issue 5; MEDLINE Ovid; Embase Ovid; the World Health Organization International Clinical Trials Registry Platform; and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions. SELECTION CRITERIA: We sought to include all randomised and non-randomised trials that assessed the hourly effect of BBPAA by ambulatory monitoring, with a minimum follow-up of three weeks. DATA COLLECTION AND ANALYSIS: Two review authors independently selected the included trials and extracted the data. We assessed the certainty of the evidence using the GRADE approach. Outcomes included in the review were end-point hourly systolic and diastolic blood pressure (SBP and DBP) and heart rate (HR), measured using a 24-hour ambulatory BP monitoring (ABPM) device. MAIN RESULTS: Fourteen non-randomised baseline controlled trials of BBPAA met our inclusion criteria, but only seven studies, involving 121 participants, reported hourly ambulatory BP data that could be included in the meta-analysis. Beta-blockers studied included acebutalol, pindolol and bopindolol. We judged most studies at high or unclear risk of bias for selection bias, attrition bias, and reporting bias. We judged the overall certainty of the evidence to be very low for all outcomes. We analysed and presented data by each hour post-dose. Very low-certainty evidence showed that hourly mean reduction in BP and HR visually showed an attenuation over time. Over the 24-hour period, the magnitude of SBP lowering at each hour ranged from -3.68 mmHg to -17.74 mmHg (7 studies, 121 participants), DBP lowering at each hour ranged from -2.27 mmHg to -9.34 mmHg (7 studies, 121 participants), and HR lowering at each hour ranged from -0.29 beats/min to -10.29 beats/min (4 studies, 71 participants). When comparing between three 8-hourly time intervals that correspond to day, evening, and night time hours, BBPAA was less effective at lowering BP and HR at night, than during the day and evening. However, because we judged that these outcomes were supported by very low-certainty evidence, further research is likely to have an important impact on the estimate of effect and may change the conclusion. AUTHORS' CONCLUSIONS: There is insufficient evidence to draw general conclusions about the degree of variation in hourly BP-lowering efficacy of BBPAA over a 24-hour period, in adults with essential hypertension. Very low-certainty evidence showed that BBPAA acebutalol, pindolol, and bopindolol lowered BP more during the day and evening than at night. However, the number of studies and participants included in this review was very small, further limiting the certainty of the evidence. We need further and larger trials, with accurate recording of time of drug intake, and with reporting of standard deviation of BP and HR at each hour.


Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Ritmo Circadiano/fisiologia , Hipertensão/tratamento farmacológico , Acebutolol/uso terapêutico , Agonistas Adrenérgicos beta/uso terapêutico , Adulto , Viés , Pressão Sanguínea/fisiologia , Ensaios Clínicos Controlados como Assunto , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Pindolol/análogos & derivados , Pindolol/uso terapêutico , Fatores de Tempo
8.
Nan Fang Yi Ke Da Xue Xue Bao ; 40(6): 822-827, 2020 Jun 30.
Artigo em Chinês | MEDLINE | ID: mdl-32895204

RESUMO

OBJECTIVE: To investigate the changes of functional connectivity (FC) in the suprachiasmatic nucleus (SCN) of patients with bipolar disorder and perform a cluster analysis of patients with bipolar disorder based on FC. METHODS: The study recruited 138 patients with bipolar disorder (BD) diagnosed according to the 4th edition of Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) and 150 healthy control subjects. All the participants underwent resting-state functional magnetic resonance brain scans. DPARSF software was used to generate the FC diagram of the SCN. Based on the FC data, principal components analysis (PCA) and k-means in scikit-learn 0.20.1 were used for cluster analysis of the patients with bipolar disorder. RESULTS: Compared with the healthy controls, the patients showed enhanced functional connections between the SCN and the paraventricular nucleus and between the SCN and the dorsomedial hypothalamus nucleus. Based on these FC values, the optimal cluster of unsupervised k-means machine learning for bipolar disorder was 2, and the Silhouette coefficient was 0.49. CONCLUSIONS: Patients with bipolar disorder have changes in the FC of the SCN, and the FC of the rhythm pathway can divide bipolar disorder into two subtypes, suggesting that biological rhythm is one of the potential biomarkers of bipolar disorder.


Assuntos
Transtorno Bipolar , Encéfalo , Ritmo Circadiano , Humanos , Imagem por Ressonância Magnética , Neuroimagem
9.
Nat Commun ; 11(1): 4643, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938935

RESUMO

Time-restricted feeding (TRF) improves metabolism independent of dietary macronutrient composition or energy restriction. To elucidate mechanisms underpinning the effects of short-term TRF, we investigated skeletal muscle and serum metabolic and transcriptomic profiles from 11 men with overweight/obesity after TRF (8 h day-1) and extended feeding (EXF, 15 h day-1) in a randomised cross-over design (trial registration: ACTRN12617000165381). Here we show that muscle core clock gene expression was similar after both interventions. TRF increases the amplitude of oscillating muscle transcripts, but not muscle or serum metabolites. In muscle, TRF induces rhythmicity of several amino acid transporter genes and metabolites. In serum, lipids are the largest class of periodic metabolites, while the majority of phase-shifted metabolites are amino acid related. In conclusion, short-term TRF in overweight men affects the rhythmicity of serum and muscle metabolites and regulates the rhythmicity of genes controlling amino acid transport, without perturbing core clock gene expression.


Assuntos
Aminoácidos/sangue , Ritmo Circadiano/genética , Jejum , Lipídeos/sangue , Músculo Esquelético/metabolismo , Adulto , Relógios Circadianos/genética , Estudos Cross-Over , Expressão Gênica , Humanos , Metabolismo dos Lipídeos , Masculino , Músculo Esquelético/fisiologia , Sobrepeso/dietoterapia , Sobrepeso/metabolismo
10.
Nat Commun ; 11(1): 4410, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32879310

RESUMO

The hypothalamic suprachiasmatic (SCN) clock contains several neurochemically defined cell groups that contribute to the genesis of circadian rhythms. Using cell-specific and genetically targeted approaches we have confirmed an indispensable role for vasoactive intestinal polypeptide-expressing SCN (SCNVIP) neurons, including their molecular clock, in generating the mammalian locomotor activity (LMA) circadian rhythm. Optogenetic-assisted circuit mapping revealed functional, di-synaptic connectivity between SCNVIP neurons and dorsomedial hypothalamic neurons, providing a circuit substrate by which SCNVIP neurons may regulate LMA rhythms. In vivo photometry revealed that while SCNVIP neurons are acutely responsive to light, their activity is otherwise behavioral state invariant. Single-nuclei RNA-sequencing revealed that SCNVIP neurons comprise two transcriptionally distinct subtypes, including putative pacemaker and non-pacemaker populations. Altogether, our work establishes necessity of SCNVIP neurons for the LMA circadian rhythm, elucidates organization of circadian outflow from and modulatory input to SCNVIP cells, and demonstrates a subpopulation-level molecular heterogeneity that suggests distinct functions for specific SCNVIP subtypes.


Assuntos
Ritmo Circadiano/fisiologia , Neurônios/metabolismo , Núcleo Supraquiasmático , Animais , Mapeamento Encefálico , Relógios Circadianos/fisiologia , Locomoção/fisiologia , Camundongos , Optogenética/métodos , Núcleo Supraquiasmático/citologia , Núcleo Supraquiasmático/metabolismo
11.
Nat Commun ; 11(1): 4411, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32879313

RESUMO

The glymphatic system is a network of perivascular spaces that promotes movement of cerebrospinal fluid (CSF) into the brain and clearance of metabolic waste. This fluid transport system is supported by the water channel aquaporin-4 (AQP4) localized to vascular endfeet of astrocytes. The glymphatic system is more effective during sleep, but whether sleep timing promotes glymphatic function remains unknown. We here show glymphatic influx and clearance exhibit endogenous, circadian rhythms peaking during the mid-rest phase of mice. Drainage of CSF from the cisterna magna to the lymph nodes exhibits daily variation opposite to glymphatic influx, suggesting distribution of CSF throughout the animal depends on time-of-day. The perivascular polarization of AQP4 is highest during the rest phase and loss of AQP4 eliminates the day-night difference in both glymphatic influx and drainage to the lymph nodes. We conclude that CSF distribution is under circadian control and that AQP4 supports this rhythm.


Assuntos
Aquaporina 4/metabolismo , Líquido Cefalorraquidiano/metabolismo , Ritmo Circadiano/fisiologia , Sistema Glinfático/metabolismo , Animais , Astrócitos/metabolismo , Encéfalo/metabolismo , Cisterna Magna/metabolismo , Linfonodos/metabolismo , Camundongos
12.
J Int Med Res ; 48(9): 300060520958594, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: covidwho-788437

RESUMO

OBJECTIVE: Coronavirus disease 2019 (COVID-19) shows a wide range of severity, ranging from an asymptomatic presentation to a severe illness requiring intensive care unit admission. Identification of a strategy to manage the severity of this disease will not only help to reduce its case fatality but also help to remove some of the burden from the already overwhelmed health care systems. While successful management of symptoms in general is important, identifying measures to modify the severity of the illness is a key factor in the fight against this pandemic. METHODS: This paper presents a short literature review to suggest a new treatment modality for COVID-19. RESULTS: COVID-19 is less severe and rarely fatal in children than in adults, which could be caused by greater fluctuations of plasma epinephrine in children. Our literature survey endorses this hypothesis according to both the epidemiological and immunological findings. CONCLUSION: Application of epinephrine pulses with a specific amplitude may be considered an intervention to minimize the severity of COVID-19.


Assuntos
Linfócitos T CD8-Positivos/efeitos dos fármacos , Ritmo Circadiano/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/epidemiologia , Epinefrina/uso terapêutico , Pandemias , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/epidemiologia , Adulto , Fatores Etários , Doenças Assintomáticas , Biomarcadores/sangue , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Criança , Ritmo Circadiano/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Esquema de Medicação , Epinefrina/sangue , Epinefrina/imunologia , Humanos , Imunidade Inata/efeitos dos fármacos , Modelos Imunológicos , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Prognóstico , Índice de Gravidade de Doença
13.
Nat Commun ; 11(1): 4706, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32943618

RESUMO

Yeast physiology is temporally regulated, this becomes apparent under nutrient-limited conditions and results in respiratory oscillations (YROs). YROs share features with circadian rhythms and interact with, but are independent of, the cell division cycle. Here, we show that YROs minimise energy expenditure by restricting protein synthesis until sufficient resources are stored, while maintaining osmotic homeostasis and protein quality control. Although nutrient supply is constant, cells sequester and store metabolic resources via increased transport, autophagy and biomolecular condensation. Replete stores trigger increased H+ export which stimulates TORC1 and liberates proteasomes, ribosomes, chaperones and metabolic enzymes from non-membrane bound compartments. This facilitates translational bursting, liquidation of storage carbohydrates, increased ATP turnover, and the export of osmolytes. We propose that dynamic regulation of ion transport and metabolic plasticity are required to maintain osmotic and protein homeostasis during remodelling of eukaryotic proteomes, and that bioenergetic constraints selected for temporal organisation that promotes oscillatory behaviour.


Assuntos
Metabolismo Energético/fisiologia , Células Eucarióticas/fisiologia , Proteostase/fisiologia , Autofagia/fisiologia , Reatores Biológicos , Ritmo Circadiano , Glicogênio/metabolismo , Resposta ao Choque Térmico , Ionomicina , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Metabolômica , Chaperonas Moleculares , Concentração Osmolar , Pressão Osmótica , Oxigênio/metabolismo , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteoma , Proteômica , Ribossomos , Leveduras/fisiologia
14.
Rev Med Suisse ; 16(706): 1684-1688, 2020 Sep 16.
Artigo em Francês | MEDLINE | ID: mdl-32936549

RESUMO

When should antihypertensive treatments be administered ? The concept of chronotherapy has been attractive for several years, in connection with the importance of circadian variations in blood pressure. The "too" promising results of the Hygia study argue in its favour. Yet experts caution us about the methodology and results of this study. Vesperal administration of routine anti-hypertensive treatments in all patients is not recommended to date, with a non-negligible risk of excessively lowering the nocturnal blood pressure in some patients (increase of ischemic risk in target organ damage) and on the other hand reducing therapeutic adherence by increasing the number of drug doses. Chronotherapy will therefore only be fully effective if patients are willing to adhere to it.


Assuntos
Anti-Hipertensivos/administração & dosagem , Cronoterapia , Hipertensão/tratamento farmacológico , Pressão Sanguínea , Ritmo Circadiano , Humanos
15.
J Int Med Res ; 48(9): 300060520958594, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32962495

RESUMO

OBJECTIVE: Coronavirus disease 2019 (COVID-19) shows a wide range of severity, ranging from an asymptomatic presentation to a severe illness requiring intensive care unit admission. Identification of a strategy to manage the severity of this disease will not only help to reduce its case fatality but also help to remove some of the burden from the already overwhelmed health care systems. While successful management of symptoms in general is important, identifying measures to modify the severity of the illness is a key factor in the fight against this pandemic. METHODS: This paper presents a short literature review to suggest a new treatment modality for COVID-19. RESULTS: COVID-19 is less severe and rarely fatal in children than in adults, which could be caused by greater fluctuations of plasma epinephrine in children. Our literature survey endorses this hypothesis according to both the epidemiological and immunological findings. CONCLUSION: Application of epinephrine pulses with a specific amplitude may be considered an intervention to minimize the severity of COVID-19.


Assuntos
Linfócitos T CD8-Positivos/efeitos dos fármacos , Ritmo Circadiano/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/epidemiologia , Epinefrina/uso terapêutico , Pandemias , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/epidemiologia , Adulto , Fatores Etários , Doenças Assintomáticas , Biomarcadores/sangue , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Criança , Ritmo Circadiano/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Esquema de Medicação , Epinefrina/sangue , Epinefrina/imunologia , Humanos , Imunidade Inata/efeitos dos fármacos , Modelos Imunológicos , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Prognóstico , Índice de Gravidade de Doença
16.
PLoS Biol ; 18(8): e3000792, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745129

RESUMO

A ubiquitous feature of the circadian clock across life forms is its organization as a network of cellular oscillators, with individual cellular oscillators within the network often exhibiting considerable heterogeneity in their intrinsic periods. The interaction of coupling and heterogeneity in circadian clock networks is hypothesized to influence clock's entrainability, but our knowledge of mechanisms governing period heterogeneity within circadian clock networks remains largely elusive. In this study, we aimed to explore the principles that underlie intercellular period variation in circadian clock networks (clonal period heterogeneity). To this end, we employed a laboratory selection approach and derived a panel of 25 clonal cell populations exhibiting circadian periods ranging from 22 to 28 h. We report that a single parent clone can produce progeny clones with a wide distribution of circadian periods, and this heterogeneity, in addition to being stochastically driven, has a heritable component. By quantifying the expression of 20 circadian clock and clock-associated genes across our clone panel, we found that inheritance of expression patterns in at least three clock genes might govern clonal period heterogeneity in circadian clock networks. Furthermore, we provide evidence suggesting that heritable epigenetic variation in gene expression regulation might underlie period heterogeneity.


Assuntos
Proteínas CLOCK/genética , Relógios Circadianos/genética , Ritmo Circadiano/genética , Epigênese Genética , Redes Reguladoras de Genes , Animais , Proteínas CLOCK/metabolismo , Linhagem Celular Tumoral , Células Clonais , Perfilação da Expressão Gênica , Genes Reporter , Heterogeneidade Genética , Humanos , Padrões de Herança , Luciferases/genética , Luciferases/metabolismo , Camundongos , Células NIH 3T3 , Osteoblastos/citologia , Osteoblastos/metabolismo , Processos Estocásticos
17.
Curr Biol ; 30(16): R930-R931, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32810450

RESUMO

The COVID-19 pandemic [1] resulted in many countries imposing a lockdown, which in turn reduces sunlight exposure and alters daily social schedules. Since these are the main entrainment factors for biological rhythms [2], we hypothesized that the lockdown may have affected sleep and circadian rhythms. We indeed show that participants slept longer and later during lockdown weekdays, and exhibited lower levels of social jetlag. While this may seem to be an overall improvement of sleep conditions, chronotype was also delayed under the lockdown. This signature of a weaker light-dark cycle should be monitored attentively since it may progressively cause disruptive effects on sleep and circadian rhythms, affecting human performance and health [3].


Assuntos
Ritmo Circadiano , Infecções por Coronavirus/complicações , Pneumonia Viral/complicações , Quarentena/psicologia , Sono/fisiologia , Adulto , Argentina , Infecções por Coronavirus/epidemiologia , Humanos , Síndrome do Jet Lag/etiologia , Pessoa de Meia-Idade , Pandemias , Fotoperíodo , Pneumonia Viral/epidemiologia , Quarentena/métodos , Inquéritos e Questionários , Fatores de Tempo
18.
Nat Commun ; 11(1): 3794, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32732906

RESUMO

Defective rhythmic metabolism is associated with high-fat high-caloric diet (HFD) feeding, ageing and obesity; however, the neural basis underlying HFD effects on diurnal metabolism remains elusive. Here we show that deletion of BMAL1, a core clock gene, in paraventricular hypothalamic (PVH) neurons reduces diurnal rhythmicity in metabolism, causes obesity and diminishes PVH neuron activation in response to fast-refeeding. Animal models mimicking deficiency in PVH neuron responsiveness, achieved through clamping PVH neuron activity at high or low levels, both show obesity and reduced diurnal rhythmicity in metabolism. Interestingly, the PVH exhibits BMAL1-controlled rhythmic expression of GABA-A receptor γ2 subunit, and dampening rhythmicity of GABAergic input to the PVH reduces diurnal rhythmicity in metabolism and causes obesity. Finally, BMAL1 deletion blunts PVH neuron responses to external stressors, an effect mimicked by HFD feeding. Thus, BMAL1-driven PVH neuron responsiveness in dynamic activity changes involving rhythmic GABAergic neurotransmission mediates diurnal rhythmicity in metabolism and is implicated in diet-induced obesity.


Assuntos
Fatores de Transcrição ARNTL/genética , Ritmo Circadiano/fisiologia , Obesidade/patologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Receptores de GABA-A/metabolismo , Animais , Ritmo Circadiano/genética , Dieta Hiperlipídica , Metabolismo Energético/fisiologia , Comportamento Alimentar/fisiologia , Camundongos , Camundongos Knockout , Neurônios/fisiologia , Obesidade/genética , Núcleo Hipotalâmico Paraventricular/citologia
19.
Artigo em Inglês | MEDLINE | ID: mdl-32791108

RESUMO

Gut microbes exhibit diurnal rhythmicity, and disruptions in this rhythmicity potentially impact host health. In this issue of Cell Host & Microbe, Reitmeier et al. (2020) employ timestamped gut microbiome sequencing data from human subjects coupled with machine learning to identify microbial rhythmicity patterns that predict Type 2 Diabetes incidence.


Assuntos
Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Microbiota , Ritmo Circadiano , Humanos
20.
Proc Biol Sci ; 287(1933): 20201001, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32811311

RESUMO

Arctic regions are highly impacted by climate change and are characterized by drastic seasonal changes in light intensity and duration with extended periods of permanent light or darkness. Organisms use cyclic variations in light to synchronize daily and seasonal biological rhythms to anticipate cyclic variations in the environment, to control phenology and to maintain fitness. In this study, we investigated the diel biological rhythms of the Arctic scallop, Chlamys islandica, during the autumnal equinox and polar night. Putative circadian clock genes and putative light perception genes were identified in the Arctic scallop. Clock gene expression oscillated in the three tissues studied (gills, muscle, mantle edge). The oscillation of some genes in some tissues shifted from daily to tidal periodicity between the equinox and polar night periods and was associated with valve behaviour. These results are the first evidence of the persistence of clock gene expression oscillations during the polar night and might suggest that functional clockwork could entrain rhythmic behaviours in polar environments.


Assuntos
Relógios Circadianos/genética , Pectinidae/fisiologia , Animais , Regiões Árticas , Ritmo Circadiano , Escuridão , Luz
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