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1.
Social Jetlag and Related Risks for Human Health: A Timely Review.
Caliandro, R, Streng, AA, van Kerkhof, LWM, van der Horst, GTJ, Chaves, I
Nutrients. 2021;(12)
Abstract
The term social jetlag is used to describe the discrepancy between biological time, determined by our internal body clock, and social times, mainly dictated by social obligations such as school or work. In industrialized countries, two-thirds of the studying/working population experiences social jetlag, often for several years. Described for the first time in 2006, a considerable effort has been put into understanding the effects of social jetlag on human physiopathology, yet our understanding of this phenomenon is still very limited. Due to its high prevalence, social jetlag is becoming a primary concern for public health. This review summarizes current knowledge regarding social jetlag, social jetlag associated behavior (e.g., unhealthy eating patterns) and related risks for human health.
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2.
Nocturnal Hypertension and Heart Failure: Mechanisms, Evidence, and New Treatments.
Kario, K, Williams, B
Hypertension (Dallas, Tex. : 1979). 2021;(3):564-577
Abstract
Heart failure (HF) is a common condition with an increasing prevalence. Despite a variety of evidence-based treatments for patients with HF with reduced ejection fraction, morbidity and mortality rates remain high. Furthermore, there are currently no treatments that have yet been shown to reduce complication and death rates in patients who have HF with preserved ejection fraction. Hypertension is a common comorbidity in patients with HF, contributing to disease development and prognosis. For example, hypertension is closely associated with the development of left ventricular hypertrophy, which an important precursor of HF. In particular, nighttime blood pressure (BP) appears to be an important, modifiable risk factor. Both nighttime BP and an abnormal circadian pattern of nighttime BP dipping have been shown to predict development of HF and the occurrence of cardiovascular events, independent of office BP. Key mechanisms for this association include sodium handling/salt sensitivity and increased sympathetic activation. These pathogenic mechanisms are targeted by several new treatment options, including sodium-glucose cotransporter 2 inhibitors, angiotensin receptor neprilysin inhibitors, mineralocorticoid receptor antagonists, and renal denervation. All of these could form part of antihypertensive strategies designed to control nighttime BP and contribute to the goal of achieving perfect 24-hour BP management. Nevertheless, additional research is needed to determine the effects of reducing nighttime BP and improving the circadian BP profile on the rate of HF, other cardiovascular events, and mortality.
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3.
Circadian Rhythms in Legumes: What Do We Know and What Else Should We Explore?
Kugan, HM, Rejab, NA, Sahruzaini, NA, Harikrishna, JA, Baisakh, N, Cheng, A
International journal of molecular sciences. 2021;(9)
Abstract
The natural timing devices of organisms, commonly known as biological clocks, are composed of specific complex folding molecules that interact to regulate the circadian rhythms. Circadian rhythms, the changes or processes that follow a 24-h light-dark cycle, while endogenously programmed, are also influenced by environmental factors, especially in sessile organisms such as plants, which can impact ecosystems and crop productivity. Current knowledge of plant clocks emanates primarily from research on Arabidopsis, which identified the main components of the circadian gene regulation network. Nonetheless, there remain critical knowledge gaps related to the molecular components of circadian rhythms in important crop groups, including the nitrogen-fixing legumes. Additionally, little is known about the synergies and trade-offs between environmental factors and circadian rhythm regulation, especially how these interactions fine-tune the physiological adaptations of the current and future crops in a rapidly changing world. This review highlights what is known so far about the circadian rhythms in legumes, which include major as well as potential future pulse crops that are packed with nutrients, particularly protein. Based on existing literature, this review also identifies the knowledge gaps that should be addressed to build a sustainable food future with the reputed "poor man's meat".
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4.
Gut microbiota as a transducer of dietary cues to regulate host circadian rhythms and metabolism.
Choi, H, Rao, MC, Chang, EB
Nature reviews. Gastroenterology & hepatology. 2021;(10):679-689
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Abstract
Certain members of the gut microbiota exhibit diurnal variations in relative abundance and function to serve as non-canonical drivers of host circadian rhythms and metabolism. Also known as microbial oscillators, these microorganisms entrain upon non-photic cues, primarily dietary, to modulate host metabolism by providing input to both circadian clock-dependent and clock-independent host networks. Microbial oscillators are generally promoted by plant-based, low-fat (lean) diets, and most are abolished by low-fibre, high-sugar, high-fat (Western) diets. The changes in microbial oscillators under different diets then affect host metabolism by altering central and peripheral host circadian clock functions and/or by directly affecting other metabolic targets. Here, we review the unique role of the gut microbiota as a non-photic regulator of host circadian rhythms and metabolism. We describe genetic, environmental, dietary and other host factors such as sex and gut immunity that determine the composition and behaviour of microbial oscillators. The mechanisms by which these oscillators regulate host circadian gene expression and metabolic state are further discussed. Because of the gut microbiota's unique role as a non-photic driver of host metabolism and circadian rhythms, the development and clinical application of novel gut microbiota-related diagnostics and therapeutics hold great promise for achieving and maintaining metabolic health.
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The importance of 24-h metabolism in obesity-related metabolic disorders: opportunities for timed interventions.
Andriessen, C, Schrauwen, P, Hoeks, J
International journal of obesity (2005). 2021;(3):479-490
Abstract
Various metabolic processes in the body oscillate throughout the natural day, driven by a biological clock. Circadian rhythms are also influenced by time cues from the environment (light exposure) and behaviour (eating and exercise). Recent evidence from diurnal- and circadian-rhythm studies indicates rhythmicity in various circulating metabolites, insulin secretion and -sensitivity and energy expenditure in metabolically healthy adults. These rhythms have been shown to be disturbed in adults with obesity-related metabolic disturbances. Moreover, eating and being (in)active at a time that the body is not prepared for it, as in night-shift work, is related to poor metabolic outcomes. These findings indicate the relevance of 24-h metabolism in obesity-related metabolic alterations and have also led to novel strategies, such as timing of food intake and exercise, to reinforce the circadian rhythm and thereby improving metabolic health. This review aims to deepen the understanding of the influence of the circadian system on metabolic processes and obesity-related metabolic disturbances and to discuss novel time-based strategies that may be helpful in combating metabolic disease.
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6.
Transcriptome and Degradome Profiling Reveals a Role of miR530 in the Circadian Regulation of Gene Expression in Kalanchoë marnieriana.
Hu, Z, Nie, Z, Yan, C, Huang, H, Ma, X, Wang, Y, Ye, N, Tuskan, GA, Yang, X, Yin, H
Cells. 2021;(6)
Abstract
Crassulacean acid metabolism (CAM) is an important photosynthetic pathway for plant adaptation to dry environments. CAM plants feature a coordinated interaction between mesophyll and epidermis functions that involves refined regulations of gene expression. Plant microRNAs (miRNAs) are crucial post-transcription regulators of gene expression, however, their roles underlying the CAM pathway remain poorly investigated. Here, we present a study characterizing the expression of miRNAs in an obligate CAM species Kalanchoë marnieriana. Through sequencing of transcriptome and degradome in mesophyll and epidermal tissues under the drought treatments, we identified differentially expressed miRNAs that were potentially involved in the regulation of CAM. In total, we obtained 84 miRNA genes, and eight of them were determined to be Kalanchoë-specific miRNAs. It is widely accepted that CAM pathway is regulated by circadian clock. We showed that miR530 was substantially downregulated in epidermal peels under drought conditions; miR530 targeted two tandem zinc knuckle/PLU3 domain encoding genes (TZPs) that were potentially involved in light signaling and circadian clock pathways. Our work suggests that the miR530-TZPs module might play a role of regulating CAM-related gene expression in Kalanchoë.
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7.
Anabolic Bone Stimulus Requires a Pre-Exercise Meal and 45-Minute Walking Impulse of Suprathreshold Speed-Enhanced Momentum to Prevent or Mitigate Postmenopausal Osteoporosis within Circadian Constraints.
Zheng, Q, Kernozek, T, Daoud-Gray, A, Borer, KT
Nutrients. 2021;(11)
Abstract
Osteoporosis currently afflicts 8 million postmenopausal women in the US, increasing the risk of bone fractures and morbidity, and reducing overall quality of life. We sought to define moderate exercise protocols that can prevent postmenopausal osteoporosis. Our previous findings singled out higher walking speed and pre-exercise meals as necessary for suppression of bone resorption and increasing of markers of bone formation. Since both studies were amenable to alternate biomechanical, nutritional, and circadian interpretations, we sought to determine the relative importance of higher speed, momentum, speed-enhanced load, duration of impulse, and meal timing on osteogenic response. We hypothesized that: (1) 20 min of exercise one hour after eating is sufficient to suppress bone resorption as much as a 40-min impulse and that two 20 min exercise bouts separated by 7 h would double the anabolic effect; (2) early morning exercise performed after eating will be as effective as mid-day exercise for anabolic outcome; and (3) the 08:00 h 40-min. exercise uphill would be as osteogenic as the 40-min exercise downhill. Healthy postmenopausal women, 8 each, were assigned to a no-exercise condition (SED) or to 40- or 20-min exercise bouts, spaced 7 h apart, for walking uphill (40 Up and 20 Up) or downhill (40 Down and 20 Down) to produce differences in biomechanical variables. Exercise was initiated at 08:00 h one hour after eating in 40-min groups, and also 7 h later, two hours after the midday meal, in 20-min groups. Measurements were made of CICP (c-terminal peptide of type I collagen), osteocalcin (OC), and bone-specific alkaline phosphatase (BALP), markers of bone formation, and of the bone resorptive marker CTX (c-terminal telopeptide of type 1 collagen). The osteogenic ratios CICP/CTX, OC/CTX, and BALP/CTX were calculated. Only the 40-min downhill exercise of suprathreshold speed-enhanced momentum, increased the three osteogenic ratios, demonstrating the necessity of a 40-min, and inadequacy of a 20-min, exercise impulse. The failure of anabolic outcome in 40-min uphill exercise was attributed to a sustained elevation of PTH concentration, as its high morning elevation enhances the CTX circadian rhythm. We conclude that postmenopausal osteoporosis can be prevented or mitigated in sedentary women by 45 min of morning exercise of suprathreshold speed-enhanced increased momentum performed shortly after a meal while walking on level ground, or by 40-min downhill, but not 40-min uphill, exercise to avoid circadian PTH oversecretion. The principal stimulus for the anabolic effect is exercise, but the prerequisite for a pre-exercise meal demonstrates the requirement for nutrient facilitation.
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8.
Association of sleep and circadian patterns and genetic risk with incident type 2 diabetes: a large prospective population-based cohort study.
Li, ZH, Zhang, PD, Chen, Q, Gao, X, Chung, VCH, Shen, D, Zhang, XR, Zhong, WF, Huang, QM, Liu, D, et al
European journal of endocrinology. 2021;(5):765-774
Abstract
OBJECTIVE To examine the association of incident type 2 diabetes (T2D) risk with sleep factors, genetic risk, and their combination effects. DESIGN Large prospective population-based cohort study. METHODS This population-based prospective cohort study included 360 403 (mean (s.d.) age: 56.6 (8.0) years) participants without T2D at baseline from the UK Biobank. Genetic risk was categorised as high (highest quintile), intermediate (quintiles: 2-4), and low (lowest quintile) based on a polygenic risk score for T2D. Sleep scores, including long or short sleep duration, insomnia, snoring, late chronotype, and excessive daytime sleepiness, were categorized as an unfavourable, intermediate, or favourable sleep and circadian pattern. RESULTS During a median follow-up of 9.0 years, 13 120 incident T2D cases were recorded. Among the participants with an unfavourable sleep and circadian pattern, 6.96% (95% CI: 6.68-7.24%) developed T2D vs 2.37% (95% CI: 2.28-2.46%) of participants with a favourable sleep and circadian pattern (adjusted hazard ratio (HR): 1.53, 95% CI: 1.45-1.62). Of participants with a high genetic risk, 5.53% (95% CI: 5.36-5.69%) developed T2D vs 2.01% (95% CI: 1.91-2.11%) of participants with a low genetic risk (adjusted HR: 2.89, 95% CI: 2.72-3.07). The association with sleep and circadian patterns was independent of genetic risk strata. Participants in the lowest quintile with an unfavourable sleep and circadian pattern were 3.97-fold more likely to develop T2D than those in the lowest quintile with a favourable sleep and circadian pattern. CONCLUSIONS Sleep and circadian patterns and genetic risk were independently associated with incident T2D. These results indicate the benefits of adhering to a healthy sleep and circadian pattern in entire populations, independent of genetic risk.
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9.
A Timely Call to Arms: COVID-19, the Circadian Clock, and Critical Care.
Haspel, J, Kim, M, Zee, P, Schwarzmeier, T, Montagnese, S, Panda, S, Albani, A, Merrow, M
Journal of biological rhythms. 2021;(1):55-70
Abstract
We currently find ourselves in the midst of a global coronavirus disease 2019 (COVID-19) pandemic, caused by the highly infectious novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we discuss aspects of SARS-CoV-2 biology and pathology and how these might interact with the circadian clock of the host. We further focus on the severe manifestation of the illness, leading to hospitalization in an intensive care unit. The most common severe complications of COVID-19 relate to clock-regulated human physiology. We speculate on how the pandemic might be used to gain insights on the circadian clock but, more importantly, on how knowledge of the circadian clock might be used to mitigate the disease expression and the clinical course of COVID-19.
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10.
Activity-rest circadian pattern and academic achievement, executive function, and intelligence in children with obesity.
Migueles, JH, Martinez-Nicolas, A, Cadenas-Sanchez, C, Esteban-Cornejo, I, Muntaner-Mas, A, Mora-Gonzalez, J, Rodriguez-Ayllon, M, Madrid, JA, Rol, MA, Hillman, CH, et al
Scandinavian journal of medicine & science in sports. 2021;(3):653-664
Abstract
This study aimed to analyze the associations of activity-rest pattern indicators with academic achievement, executive function, and intelligence and to explore whether these associations are mediated by the total gray matter volume among children with overweight/obesity. Ninety-five children (10 ± 1 year, 37 girls) with overweight/obesity (based on the World Obesity Federation body mass index cutoff points) were included in this cross-sectional study. Hip- and wrist-worn ActiGraph GT3X + accelerometers were used to assess the activity-rest pattern. Interdaily stability (IS), intradaily variability (IV), the mean value of the lowest 5 hours (L5), and the mean value of the maximum 10 hours (M10) of activity and their respective timing (TL5, TM10) were used as indicators of the activity-rest pattern throughout the day. Chronotype and social jetlag were used as indicators of circadian preference. Academic achievement, executive function, and intelligence were assessed with standardized tests. Gray matter volume was acquired by magnetic resonance imaging (MRI). IS was positively associated with executive function (β = 0.244, P = .014). IV was negatively associated with mathematics and academic applications (β: -0.211 to -0.238, P's ≤ .026). Later TM10 in the day was related to lower writing, academic skills, and intelligence (β: -0.229 to -0.271, P's ≤ .025). None of the associations found were mediated by gray matter volume. A non-fragmented and stable activity-rest pattern and earlier physical activity in the day were associated with better academic achievement, executive function, and intelligence in children with overweight/obesity. Further studies are required to corroborate or contrast our findings.