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Cox OH, Gianonni-Guzmán MA, Cartailler JP, Cottam MA, McMahon DG. Transcriptomic Plasticity of the Circadian Clock in Response to Photoperiod: A Study in Male Melatonin-Competent Mice. J Biol Rhythms 2024:7487304241265439. [PMID: 39096022 DOI: 10.1177/07487304241265439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Seasonal daylength, or circadian photoperiod, is a pervasive environmental signal that profoundly influences physiology and behavior. In mammals, the central circadian clock resides in the suprachiasmatic nuclei (SCN) of the hypothalamus where it receives retinal input and synchronizes, or entrains, organismal physiology and behavior to the prevailing light cycle. The process of entrainment induces sustained plasticity in the SCN, but the molecular mechanisms underlying SCN plasticity are incompletely understood. Entrainment to different photoperiods persistently alters the timing, waveform, period, and light resetting properties of the SCN clock and its driven rhythms. To elucidate novel candidate genes for molecular mechanisms of photoperiod plasticity, we performed RNA sequencing on whole SCN dissected from mice raised in long (light:dark [LD] 16:8) and short (LD 8:16) photoperiods. Fewer rhythmic genes were detected in mice subjected to long photoperiod, and in general, the timing of gene expression rhythms was advanced 4-6 h. However, a few genes showed significant delays, including Gem. There were significant changes in the expression of the clock-associated gene Timeless and in SCN genes related to light responses, neuropeptides, gamma aminobutyric acid (GABA), ion channels, and serotonin. Particularly striking were differences in the expression of the neuropeptide signaling genes Prokr2 and Cck, as well as convergent regulation of the expression of 3 SCN light response genes, Dusp4, Rasd1, and Gem. Transcriptional modulation of Dusp4 and Rasd1 and phase regulation of Gem are compelling candidate molecular mechanisms for plasticity in the SCN light response through their modulation of the critical NMDAR-MAPK/ERK-CREB/CRE light signaling pathway in SCN neurons. Modulation of Prokr2 and Cck may critically support SCN neural network reconfiguration during photoperiodic entrainment. Our findings identify the SCN light response and neuropeptide signaling gene sets as rich substrates for elucidating novel mechanisms of photoperiod plasticity. Data are also available at http://circadianphotoperiodseq.com/, where users can view the expression and rhythmic properties of genes across these photoperiod conditions.
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Affiliation(s)
- Olivia H Cox
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee
| | | | - Jean-Philippe Cartailler
- The Vanderbilt Creative Data Solutions Shared Resource, Vanderbilt University, Nashville, Tennessee
| | - Matthew A Cottam
- The Vanderbilt Creative Data Solutions Shared Resource, Vanderbilt University, Nashville, Tennessee
| | - Douglas G McMahon
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee
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2
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Bjerrum LB, Nordhus IH, Sørensen L, Wulff K, Bjorvatn B, Flo-Groeneboom E, Visted E. Acute effects of light during daytime on central aspects of attention and affect: A systematic review. Biol Psychol 2024; 192:108845. [PMID: 38981576 DOI: 10.1016/j.biopsycho.2024.108845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/29/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024]
Abstract
Light regulates both image- and various non-image forming responses in humans, including acute effects on attention and affect. To advance the understanding of light's immediate effects, this systematic review describes the acute effects of monochromatic/narrow bandwidth and polychromatic white light during daytime on distinct aspects of attention (alertness, sustained attention, working memory, attentional control and flexibility), and measures of affect (self-report measures, performance-based tests, psychophysiological measures) in healthy, adult human subjects. Original, peer-reviewed (quasi-) experimental studies published between 2000 and May 2024 were included according to predefined inclusion and exclusion criteria. Study quality was assessed, and results were synthesized across aspects of attention and affect and grouped according to light interventions; monochromatic/narrowband-width or polychromatic white light (regular white, bright white, and white with high correlated color temperature (CCT)). Results from included studies (n = 62) showed that alertness and working memory were most affected by light. Electroencephalographic markers of alertness improved the most with exposure to narrow bandwidth long-wavelength light, regular white, and white light with high CCT. Self-reported alertness and measures of working memory improved the most with bright white light. Results from studies testing the acute effects on sustained attention and attentional control and flexibility were inconclusive. Performance-based and psychophysiological measures of affect were only influenced by narrow bandwidth long-wavelength light. Polychromatic white light exerted mixed effects on self-reported affect. Studies were strongly heterogeneous in terms of light stimuli characteristics and reporting of light stimuli and control of variables influencing light's acute effects.
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Affiliation(s)
| | | | - Lin Sørensen
- Department of Biological and Medical Psychology, University of Bergen, Norway
| | - Katharina Wulff
- Department of Molecular Biology, Umeå University, Sweden; Wallenberg Centre for Molecular Medicine, Umeå University, Sweden
| | - Bjørn Bjorvatn
- Department of Global Public Health and Primary Care, University of Bergen, Norway; Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Norway
| | | | - Endre Visted
- Department of Clinical Psychology, University of Bergen, Norway
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Cox OH, Gianonni-Guzmán MA, Cartailler JP, Cottam MA, McMahon DG. Gene expression plasticity of the mammalian brain circadian clock in response to photoperiod. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.16.580759. [PMID: 38586021 PMCID: PMC10996532 DOI: 10.1101/2024.02.16.580759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Seasonal daylength, or circadian photoperiod, is a pervasive environmental signal that profoundly influences physiology and behavior. In mammals, the central circadian clock resides in the suprachiasmatic nuclei (SCN) of the hypothalamus where it receives retinal input and synchronizes, or entrains, organismal physiology and behavior to the prevailing light cycle. The process of entrainment induces sustained plasticity in the SCN, but the molecular mechanisms underlying SCN plasticity are incompletely understood. Entrainment to different photoperiods persistently alters the timing, waveform, period, and light resetting properties of the SCN clock and its driven rhythms. To elucidate novel molecular mechanisms of photoperiod plasticity, we performed RNAseq on whole SCN dissected from mice raised in Long (LD 16:8) and Short (LD 8:16) photoperiods. Fewer rhythmic genes were detected in Long photoperiod and in general the timing of gene expression rhythms was advanced 4-6 hours. However, a few genes showed significant delays, including Gem . There were significant changes in the expression clock-associated gene Timeless and in SCN genes related to light responses, neuropeptides, GABA, ion channels, and serotonin. Particularly striking were differences in the expression of the neuropeptide signaling genes Prokr2 and Cck , as well as convergent regulation of the expression of three SCN light response genes, Dusp4 , Rasd1 , and Gem . Transcriptional modulation of Dusp4 and Rasd1, and phase regulation of Gem, are compelling candidate molecular mechanisms for plasticity in the SCN light response through their modulation of the critical NMDAR-MAPK/ERK-CREB/CRE light signaling pathway in SCN neurons. Modulation of Prokr2 and Cck may critically support SCN neural network reconfiguration during photoperiodic entrainment. Our findings identify the SCN light response and neuropeptide signaling gene sets as rich substrates for elucidating novel mechanisms of photoperiod plasticity.
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Schöllhorn I, Stefani O, Blume C, Cajochen C. Seasonal Variation in the Responsiveness of the Melanopsin System to Evening Light: Why We Should Report Season When Collecting Data in Human Sleep and Circadian Studies. Clocks Sleep 2023; 5:651-666. [PMID: 37987395 PMCID: PMC10660855 DOI: 10.3390/clockssleep5040044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/07/2023] [Accepted: 10/09/2023] [Indexed: 11/22/2023] Open
Abstract
It is well known that variations in light exposure during the day affect light sensitivity in the evening. More daylight reduces sensitivity, and less daylight increases it. On average days, we spend less time outdoors in winter and receive far less light than in summer. Therefore, it could be relevant when collecting research data on the non-image forming (NIF) effects of light on circadian rhythms and sleep. In fact, studies conducted only in winter may result in more pronounced NIF effects than in summer. Here, we systematically collected information on the extent to which studies on the NIF effects of evening light include information on season and/or light history. We found that more studies were conducted in winter than in summer and that reporting when a study was conducted or measuring individual light history is not currently a standard in sleep and circadian research. In addition, we sought to evaluate seasonal variations in a previously published dataset of 72 participants investigating circadian and sleep effects of evening light exposure in a laboratory protocol where daytime light history was not controlled. In this study, we selectively modulated melanopic irradiance at four different light levels (<90 lx). Here, we aimed to retrospectively evaluate seasonal variations in the responsiveness of the melanopsin system by combining all data sets in an exploratory manner. Our analyses suggest that light sensitivity is indeed reduced in summer compared to winter. Thus, to increase the reproducibility of NIF effects on sleep and circadian measures, we recommend an assessment of the light history and encourage standardization of reporting guidelines on the seasonal distribution of measurements.
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Affiliation(s)
- Isabel Schöllhorn
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4002 Basel, Switzerland; (I.S.); (O.S.)
- Research Cluster Molecular and Cognitive Neurosciences (MCN), University of Basel, 4001 Basel, Switzerland
| | - Oliver Stefani
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4002 Basel, Switzerland; (I.S.); (O.S.)
- Research Cluster Molecular and Cognitive Neurosciences (MCN), University of Basel, 4001 Basel, Switzerland
- Lucerne University of Applied Sciences and Arts, Engineering and Architecture, Technikumstrasse 21, 6048 Horw, Switzerland
| | - Christine Blume
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4002 Basel, Switzerland; (I.S.); (O.S.)
- Research Cluster Molecular and Cognitive Neurosciences (MCN), University of Basel, 4001 Basel, Switzerland
- Department of Biomedicine, University of Basel, 4001 Basel, Switzerland
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4002 Basel, Switzerland; (I.S.); (O.S.)
- Research Cluster Molecular and Cognitive Neurosciences (MCN), University of Basel, 4001 Basel, Switzerland
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Eto T, Higuchi S. Review on age-related differences in non-visual effects of light: melatonin suppression, circadian phase shift and pupillary light reflex in children to older adults. J Physiol Anthropol 2023; 42:11. [PMID: 37355647 DOI: 10.1186/s40101-023-00328-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 06/15/2023] [Indexed: 06/26/2023] Open
Abstract
Physiological effects of light exposure in humans are diverse. Among them, the circadian rhythm phase shift effect in order to maintain a 24-h cycle of the biological clock is referred to as non-visual effects of light collectively with melatonin suppression and pupillary light reflex. The non-visual effects of light may differ depending on age, and clarifying age-related differences in the non-visual effects of light is important for providing appropriate light environments for people of different ages. Therefore, in various research fields, including physiological anthropology, many studies on the effects of age on non-visual functions have been carried out in older people, children and adolescents by comparing the effects with young adults. However, whether the non-visual effects of light vary depending on age and, if so, what factors contribute to the differences have remained unclear. In this review, results of past and recent studies on age-related differences in the non-visual effects of light are presented and discussed in order to provide clues for answering the question of whether non-visual effects of light actually vary depending on age. Some studies, especially studies focusing on older people, have shown age-related differences in non-visual functions including differences in melatonin suppression, circadian phase shift and pupillary light reflex, while other studies have shown no differences. Studies showing age-related differences in the non-visual effects of light have suspected senile constriction and crystalline lens opacity as factors contributing to the differences, while studies showing no age-related differences have suspected the presence of a compensatory mechanism. Some studies in children and adolescents have shown that children's non-visual functions may be highly sensitive to light, but the studies comparing with other age groups seem to have been limited. In order to study age-related differences in non-visual effects in detail, comparative studies should be conducted using subjects having a wide range of ages and with as much control as possible for intensity, wavelength component, duration, circadian timing, illumination method of light exposure, and other factors (mydriasis or non-mydriasis, cataracts or not in the older adults, etc.).
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Affiliation(s)
- Taisuke Eto
- Research Fellow of the Japan Society for the Promotion of Science, Kodaira, Japan
- Department of Sleep-Wake Disorders, National Center of Neurology and Psychiatry, National Institute of Mental Health, Kodaira, Japan
| | - Shigekazu Higuchi
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, Fukuoka, Japan.
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Kalita E, Panda M, Prajapati VK. The interplay between circadian clock and viral infections: A molecular perspective. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 137:293-330. [PMID: 37709380 DOI: 10.1016/bs.apcsb.2023.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
The circadian clock influences almost every aspect of mammalian behavioral, physiological and metabolic processes. Being a hierarchical network, the circadian clock is driven by the central clock in the brain and is composed of several peripheral tissue-specific clocks. It orchestrates and synchronizes the daily oscillations of biological processes to the environment. Several pathological events are influenced by time and seasonal variations and as such implicate the clock in pathogenesis mechanisms. In context with viral infections, circadian rhythmicity is closely associated with host susceptibility, disease severity, and pharmacokinetics and efficacies of antivirals and vaccines. Leveraging the circadian molecular mechanism insights has increased our understanding of clock infection biology and proposes new avenues for viral diagnostics and therapeutics. In this chapter, we address the molecular interplay between the circadian clock and viral infections and discuss the importance of chronotherapy as a complementary approach to conventional medicines, emphasizing the significance of virus-clock studies.
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Affiliation(s)
- Elora Kalita
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Mamta Panda
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, India..
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Sanjita Devi H, Rajiv C, Mondal G, Khan ZA, Devi SD, Bharali R, Chattoraj A. Influence of photoperiod variations on the mRNA expression pattern of melatonin bio-synthesizing enzyme genes in the pineal organ and retina: A study in relation to the serum melatonin profile in the tropical carp Catla catla. JOURNAL OF FISH BIOLOGY 2022; 101:1569-1581. [PMID: 36205436 DOI: 10.1111/jfb.15234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Surface-dwelling C. catla were exposed to different photoperiods (8L:16D, 12L:12D, 12D:12L and 16L:8D) and the mRNA level profile of enzymes involved in melatonin synthesis was evaluated in the pineal gland and retina. Furthermore, a comparative analysis of the serum melatonin profile with the mRNA level was also performed. The results indicated diurnal variations in the transcripts of tph1, aanat and hiomt in the pineal organ and retina, and these variations change with the change in lighting regime. The serum melatonin profile showed rhythmicity in the natural photoperiod, but the serum melatonin level increased proportionally with increasing daylength. In short photoperiods, the peak value (though lower than in long photoperiods) of melatonin maintains a longer duration in serum. Moreover, the comparative analysis revealed a similar profile of mRNA of pineal aanat1 and aanat2 with serum melatonin under the same lighting conditions. This indicates that serum melatonin is produced by the pineal gland. Our results specify the importance of day length and the timing of onset or offset of the dark for maintaining the oscillating levels of serum melatonin and mRNA levels of melatonin biosynthesizing enzyme genes in the pineal organ and retina as well. The findings in this study highlight the distinctive pattern of mRNA levels in the pineal organ and retina under different photoperiods. The pineal melatonin biosynthesizing enzyme genes showed a similar pattern with serum melatonin levels while the retinal genes changed dramatically with photoperiod. We also revealed a light-dependent transcriptional regulation of pineal aanat genes in C. catla. Moreover, our results suggest that ALAN and skyglow can influence the levels of serum melatonin and its biosynthesis, resulting in desynchronization of the entire biological clock as well as the overall physiology of the animal.
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Affiliation(s)
| | - Chongtham Rajiv
- Department of Biotechnology, Government of India, Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Imphal, India
| | - Gopinath Mondal
- Department of Biotechnology, Government of India, Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Imphal, India
| | - Zeeshan Ahmad Khan
- Department of Biotechnology, Government of India, Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Imphal, India
| | - Sijagurumayum Dharmajyoti Devi
- Department of Biotechnology, Government of India, Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Imphal, India
| | - Rupjyoti Bharali
- Department of Biotechnology, Gauhati University, Guwahati, India
| | - Asamanja Chattoraj
- Biological Rhythm Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, India
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Pearson JA, Voisey AC, Boest-Bjerg K, Wong FS, Wen L. Circadian Rhythm Modulation of Microbes During Health and Infection. Front Microbiol 2021; 12:721004. [PMID: 34512600 PMCID: PMC8430216 DOI: 10.3389/fmicb.2021.721004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/05/2021] [Indexed: 12/11/2022] Open
Abstract
Circadian rhythms, referring to 24-h daily oscillations in biological and physiological processes, can significantly regulate host immunity to pathogens, as well as commensals, resulting in altered susceptibility to disease development. Furthermore, vaccination responses to microbes have also shown time-of-day-dependent changes in the magnitude of protective immune responses elicited in the host. Thus, understanding host circadian rhythm effects on both gut bacteria and viruses during infection is important to minimize adverse effects on health and identify optimal times for therapeutic administration to maximize therapeutic success. In this review, we summarize the circadian modulations of gut bacteria, viruses and their interactions, both in health and during infection. We also discuss the importance of chronotherapy (i.e., time-specific therapy) as a plausible therapeutic administration strategy to enhance beneficial therapeutic responses.
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Affiliation(s)
- James Alexander Pearson
- Diabetes Research Group, Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Alexander Christopher Voisey
- Diabetes Research Group, Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Kathrine Boest-Bjerg
- Diabetes Research Group, Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - F. Susan Wong
- Diabetes Research Group, Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Li Wen
- Section of Endocrinology, Internal Medicine, School of Medicine, Yale University, New Haven, CT, United States
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Lai KY, Sarkar C, Ni MY, Gallacher J, Webster C. Exposure to light at night (LAN) and risk of obesity: A systematic review and meta-analysis of observational studies. ENVIRONMENTAL RESEARCH 2020; 187:109637. [PMID: 32497902 DOI: 10.1016/j.envres.2020.109637] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/18/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND There is emerging evidence of the association between light at night (LAN) exposure and weight gain. OBJECTIVE We aim to conduct a systematic review and meta-analysis of observational studies on the association between LAN exposure and risk of obesity in human subjects. METHODS Peer-reviewed observational studies were systematically searched from MEDLINE (EBSCO), Academic Search Complete (EBSCO), CINAHL Plus (EBSCO) and PubMed up to December 24, 2019. Random-effects models were developed to estimate the associations between LAN exposure and weight-related outcomes of overweight and obesity as measured by body mass index (BMI), waist circumference, waist-hip-ratio and waist-to-height-ratio. The I2 statistic was used to assess the degree of heterogeneity across studies. The National Toxicology Program's Office of Health Assessment and Translation (OHAT) risk of bias rating tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guideline were respectively employed to assess the risk of bias and to appraise the quality of the generated evidence. RESULTS A total of 12 studies (three with longitudinal and nine of cross-sectional design) published between 2003 and 2019 were included for systematic review, while seven of them fulfilling the inclusion/exclusion criteria were included in the meta-analysis. A higher LAN exposure was significantly associated with 13% higher odds of overweight (BMI≥25 kg/m2) (Summary Odds Ratio; SOR: 1.13, 95% CI: 1.10-1.16) with low heterogeneity (I2 = 27.27%), and 22% higher odds of obesity (BMI≥30 kg/m2) (SOR: 1.22, 95% CI: 1.07-1.38) with substantial heterogeneity (I2 = 85.96%). Stratifying analyses by the levels of measurement of LAN exposures (macro-, meso- and micro-levels) and time of LAN measurement (including before and while sleeping) consistently produced robust estimates, with higher exposure to LAN being positively associated with poorer weight outcomes. Assessment of risk of bias identified substantial detection bias for exposure, with over half of the pooled studies employing subjective LAN measures. The overall evidence of the association between LAN exposure and risk of obesity was rated as 'moderate' as per the GRADE guideline. CONCLUSIONS Exposure to LAN was reported to be a significant risk factor for overweight and obesity. Prospectively designed future studies with objectively measured multi-level LAN exposures and weight outcomes are required.
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Affiliation(s)
- Ka Yan Lai
- Healthy High Density Cities Lab, HKUrbanLab, The University of Hong Kong, Knowles Building, Pokfulam Road, Pokfulam, Hong Kong Special Administrative Region, China
| | - Chinmoy Sarkar
- Healthy High Density Cities Lab, HKUrbanLab, The University of Hong Kong, Knowles Building, Pokfulam Road, Pokfulam, Hong Kong Special Administrative Region, China; School of Public Health, The University of Hong Kong, Patrick Manson Building, Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, China.
| | - Michael Y Ni
- Healthy High Density Cities Lab, HKUrbanLab, The University of Hong Kong, Knowles Building, Pokfulam Road, Pokfulam, Hong Kong Special Administrative Region, China; School of Public Health, The University of Hong Kong, Patrick Manson Building, Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, China; The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - John Gallacher
- Department of Psychiatry, Oxford University, Warneford Hospital, Oxford, UK
| | - Chris Webster
- Healthy High Density Cities Lab, HKUrbanLab, The University of Hong Kong, Knowles Building, Pokfulam Road, Pokfulam, Hong Kong Special Administrative Region, China
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Lee SI, Kinoshita S, Noguchi A, Eto T, Ohashi M, Nishimura Y, Maeda K, Motomura Y, Awata Y, Higuchi S. Melatonin suppression during a simulated night shift in medium intensity light is increased by 10-minute breaks in dim light and decreased by 10-minute breaks in bright light. Chronobiol Int 2020; 37:897-909. [PMID: 32326827 DOI: 10.1080/07420528.2020.1752704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Exposure to light at night results in disruption of endogenous circadian rhythmicity and/or suppression of pineal melatonin, which can consequently lead to acute or chronic adverse health problems. In the present study, we investigated whether exposure to very dim light or very bright light for a short duration influences melatonin suppression, subjective sleepiness, and performance during exposure to constant moderately bright light. Twenty-four healthy male university students were divided into two experimental groups: Half of them (mean age: 20.0 ± 0.9 years) participated in an experiment for short-duration (10 min) light conditions of medium intensity light (430 lx, medium breaks) vs. very dim light (< 1 lx, dim breaks) and the other half (mean age: 21.3 ± 2.5 years) participated in an experiment for short-duration light conditions of medium intensity light (430 lx, medium breaks) vs. very bright light (4700 lx, bright breaks). Each simulated night shift consisting of 5 sets (each including 50-minute night work and 10-minute break) was performed from 01:00 to 06:00 h. The subjects were exposed to medium intensity light (550 lx) during the night work. Each 10-minute break was conducted every hour from 02:00 to 06:00 h. Salivary melatonin concentrations were measured, subjective sleepiness was assessed, the psychomotor vigilance task was performed at hourly intervals from 21:00 h until the end of the experiment. Compared to melatonin suppression between 04:00 and 06:00 h in the condition of medium breaks, the condition of dim breaks significantly promoted melatonin suppression and the condition of bright breaks significantly diminished melatonin suppression. However, there was no remarkable effect of either dim breaks or bright breaks on subjective sleepiness and performance of the psychomotor vigilance task. Our findings suggest that periodic exposure to light for short durations during exposure to a constant light environment affects the sensitivity of pineal melatonin to constant light depending on the difference between light intensities in the two light conditions (i.e., short light exposure vs. constant light exposure). Also, our findings indicate that exposure to light of various intensities at night could be a factor influencing the light-induced melatonin suppression in real night work settings.
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Affiliation(s)
- Sang-Il Lee
- Department of Human Science, Faculty of Design, Kyushu University , Fukuoka, Japan.,Division of Human Environmental Systems, Faculty of Engineering, Hokkaido University , Sapporo, Japan
| | - Saki Kinoshita
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Anna Noguchi
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Taisuke Eto
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Michihiro Ohashi
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Yuki Nishimura
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan.,Occupational Stress and Health Management Research Group, National Institute of Occupational Safety and Health , Kawasaki, Japan
| | - Kaho Maeda
- Ground Facilities Department, Japan Aerospace Exploration Agency , Tsukuba, Japan
| | - Yuki Motomura
- Department of Human Science, Faculty of Design, Kyushu University , Fukuoka, Japan
| | - Yasuhiro Awata
- Ground Facilities Department, Japan Aerospace Exploration Agency , Tsukuba, Japan
| | - Shigekazu Higuchi
- Department of Human Science, Faculty of Design, Kyushu University , Fukuoka, Japan
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11
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Khan ZA, Yumnamcha T, Mondal G, Devi SD, Rajiv C, Labala RK, Sanjita Devi H, Chattoraj A. Artificial Light at Night (ALAN): A Potential Anthropogenic Component for the COVID-19 and HCoVs Outbreak. Front Endocrinol (Lausanne) 2020; 11:622. [PMID: 33013700 PMCID: PMC7511708 DOI: 10.3389/fendo.2020.00622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/30/2020] [Indexed: 12/18/2022] Open
Abstract
The origin of the coronavirus disease 2019 (COVID-19) pandemic is zoonotic. The circadian day-night is the rhythmic clue to organisms for their synchronized body functions. The "development for mankind" escalated the use of artificial light at night (ALAN). In this article, we tried to focus on the possible influence of this anthropogenic factor in human coronavirus (HCoV) outbreak. The relationship between the occurrences of coronavirus and the ascending curve of the night-light has also been delivered. The ALAN influences the physiology and behavior of bat, a known nocturnal natural reservoir of many Coronaviridae. The "threatened" and "endangered" status of the majority of bat species is mainly because of the destruction of their proper habit and habitat predominantly through artificial illumination. The stress exerted by ALAN leads to the impaired body functions, especially endocrine, immune, genomic integration, and overall rhythm features of different physiological variables and behaviors in nocturnal animals. Night-light disturbs "virus-host" synchronization and may lead to mutation in the genomic part of the virus and excessive virus shedding. We also proposed some future strategies to mitigate the repercussions of ALAN and for the protection of the living system in the earth as well.
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Affiliation(s)
- Zeeshan Ahmad Khan
- Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
| | - Thangal Yumnamcha
- Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
| | - Gopinath Mondal
- Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
| | - Sijagurumayum Dharmajyoti Devi
- Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
| | - Chongtham Rajiv
- Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
| | - Rajendra Kumar Labala
- Distributed Information Sub-centre, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
- Biological Rhythm Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, India
| | - Haobijam Sanjita Devi
- Biological Rhythm Laboratory, Animal Resources Programme, Institute of Bioresources and Sustainable Development, Department of Biotechnology, Government of India, Imphal, India
| | - Asamanja Chattoraj
- Biological Rhythm Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, India
- *Correspondence: Asamanja Chattoraj ;
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Summer-winter difference in 24-h melatonin rhythms in subjects on a 5-workdays schedule in Siberia without daylight saving time transitions. Physiol Behav 2019; 212:112686. [DOI: 10.1016/j.physbeh.2019.112686] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 08/07/2019] [Accepted: 09/19/2019] [Indexed: 11/17/2022]
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Wahl S, Engelhardt M, Schaupp P, Lappe C, Ivanov IV. The inner clock-Blue light sets the human rhythm. JOURNAL OF BIOPHOTONICS 2019; 12:e201900102. [PMID: 31433569 PMCID: PMC7065627 DOI: 10.1002/jbio.201900102] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/02/2019] [Accepted: 08/18/2019] [Indexed: 05/06/2023]
Abstract
Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24-hour cycle. Short wavelengths, perceived as blue color, are the strongest synchronizing agent for the circadian system that keeps most biological and psychological rhythms internally synchronized. Circadian rhythm is important for optimum function of organisms and circadian sleep-wake disruptions or chronic misalignment often may lead to psychiatric and neurodegenerative illness. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion, the hormone that is produced by the pineal gland and plays crucial role in circadian rhythm entrainment. While the exposure to blue is important for keeping organism's wellbeing, alertness, and cognitive performance during the day, chronic exposure to low-intensity blue light directly before bedtime, may have serious implications on sleep quality, circadian phase and cycle durations. This rises inevitably the need for solutions to improve wellbeing, alertness, and cognitive performance in today's modern society where exposure to blue light emitting devices is ever increasing.
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Affiliation(s)
- Siegfried Wahl
- Institute for Ophthalmic ResearchUniversity of TuebingenTuebingenGermany
- Carl Zeiss Vision International GmbHAalenGermany
| | - Moritz Engelhardt
- Institute for Ophthalmic ResearchUniversity of TuebingenTuebingenGermany
| | | | | | - Iliya V. Ivanov
- Institute for Ophthalmic ResearchUniversity of TuebingenTuebingenGermany
- Carl Zeiss Vision International GmbHAalenGermany
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Lok R, Woelders T, Gordijn MCM, Hut RA, Beersma DGM. White Light During Daytime Does Not Improve Alertness in Well-rested Individuals. J Biol Rhythms 2018; 33:637-648. [PMID: 30191761 PMCID: PMC6236585 DOI: 10.1177/0748730418796036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Broad-spectrum light applied during the night has been shown to affect alertness in a
dose-dependent manner. The goal of this experiment was to investigate whether a similar
relationship could be established for light exposure during daytime. Fifty healthy
participants were subjected to a paradigm (0730-1730 h) in which they were intermittently
exposed to 1.5 h of dim light (<10 lux) and 1 h of experimental light (24-2000 lux).
The same intensity of experimental light was used throughout the day, resulting in groups
of 10 subjects per intensity. Alertness was assessed with subjective and multiple
objective measures. A significant effect of time of day was found in all parameters of
alertness (p < 0.05). Significant dose-response relationships between
light intensity and alertness during the day could be determined in a few of the
parameters of alertness at some times of the day; however, none survived correction for
multiple testing. We conclude that artificial light applied during daytime at intensities
up to 2000 lux does not elicit significant improvements in alertness in non-sleep-deprived
subjects.
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Affiliation(s)
- Renske Lok
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
| | - Tom Woelders
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
| | - Marijke C M Gordijn
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands.,Chrono@Work, Groningen, the Netherlands
| | - Roelof A Hut
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
| | - Domien G M Beersma
- University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands
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Seasonal Variation in Bright Daylight Exposure, Mood and Behavior among a Group of Office Workers in Sweden. J Circadian Rhythms 2018; 16:2. [PMID: 30210562 PMCID: PMC5853818 DOI: 10.5334/jcr.153] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The purpose of the study was to investigate seasonal variation in mood and behavior among a group of office workers in Sweden (56°N). Thirty subjects participated in this longitudinal study. The subjects kept a weekly log that included questionnaires for ratings of psychological wellbeing and daily sleep-activity diaries where they also noted time spent outdoors. The lighting conditions in the offices were subjectively evaluated during one day, five times over the year. There was a seasonal variation in positive affect and in sleep-activity behavior. Across the year, there was a large variation in the total time spent outdoors in daylight. The subjects reported seasonal variation concerning the pleasantness, variation and strength of the light in the offices and regarding the visibility in the rooms. Finally, the subjects spent most of their time indoors, relying on artificial lighting, which demonstrates the importance of the lighting quality in indoor environments.
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Souman JL, Tinga AM, te Pas SF, van Ee R, Vlaskamp BN. Acute alerting effects of light: A systematic literature review. Behav Brain Res 2018; 337:228-239. [DOI: 10.1016/j.bbr.2017.09.016] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/01/2017] [Accepted: 09/07/2017] [Indexed: 10/18/2022]
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Abstract
Diurnal preference, or chronotype, determined partly by genetics and modified by age, activity, and the environment, defines the time of day at which one feels at his/her best, when one feels sleepy, and when one would prefer to start his/her day. Chronotype affects the phase relationship of an individual's circadian clock with the environment such that morning types have earlier-phased circadian rhythms than evening types. The phases of circadian rhythms are synchronized to the environment on a daily basis, undergoing minor adjustments of phase each day. Light is the most potent time cue for phase-shifting circadian rhythms, but the timing and amount of solar irradiation vary dynamically with season, especially with increasing distance from the equator. There is evidence that chronotype is modified by seasonal change, most likely due to the changes in the light environment, but interindividual differences in photoperiod responsiveness mean that some people are more affected than others. Differences in circadian light sensitivity due to endogenous biological reasons and/or previous light history are responsible for the natural variation in photoperiod responsiveness. Modern lifestyles that include access to artificial light at night, temperature-controlled environments, and spending much less time outdoors offer a buffer to the environmental changes of the seasons and may contribute to humans becoming less responsive to seasons.
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Affiliation(s)
- Nyambura Shawa
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa,
| | - Dale E Rae
- Health through Physical Activity, Lifestyle and Sport Research Centre, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Laura C Roden
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa,
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Akiyama T, Katsumura T, Nakagome S, Lee SI, Joh K, Soejima H, Fujimoto K, Kimura R, Ishida H, Hanihara T, Yasukouchi A, Satta Y, Higuchi S, Oota H. An ancestral haplotype of the human PERIOD2 gene associates with reduced sensitivity to light-induced melatonin suppression. PLoS One 2017. [PMID: 28650999 PMCID: PMC5484468 DOI: 10.1371/journal.pone.0178373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Humans show various responses to the environmental stimulus in individual levels as “physiological variations.” However, it has been unclear if these are caused by genetic variations. In this study, we examined the association between the physiological variation of response to light-stimulus and genetic polymorphisms. We collected physiological data from 43 subjects, including light-induced melatonin suppression, and performed haplotype analyses on the clock genes, PER2 and PER3, exhibiting geographical differentiation of allele frequencies. Among the haplotypes of PER3, no significant difference in light sensitivity was found. However, three common haplotypes of PER2 accounted for more than 96% of the chromosomes in subjects, and 1 of those 3 had a significantly low-sensitive response to light-stimulus (P < 0.05). The homozygote of the low-sensitive PER2 haplotype showed significantly lower percentages of melatonin suppression (P < 0.05), and the heterozygotes of the haplotypes varied their ratios, indicating that the physiological variation for light-sensitivity is evidently related to the PER2 polymorphism. Compared with global haplotype frequencies, the haplotype with a low-sensitive response was more frequent in Africans than in non-Africans, and came to the root in the phylogenetic tree, suggesting that the low light-sensitive haplotype is the ancestral type, whereas the other haplotypes with high sensitivity to light are the derived types. Hence, we speculate that the high light-sensitive haplotypes have spread throughout the world after the Out-of-Africa migration of modern humans.
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Affiliation(s)
- Tokiho Akiyama
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
- Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa, Japan
| | - Takafumi Katsumura
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Shigeki Nakagome
- Department of Mathematical Analysis and Statistical Inference, The Institute of Statistical Mathematics, Tachikawa, Tokyo, Japan
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
| | - Sang-il Lee
- Department of Human Science, Faculty of Design, Kyushu University, Minami-ku Fukuoka, Japan
| | - Keiichiro Joh
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Science, Faculty of Medicine, Saga University, Nabeshima, Saga, Japan
| | - Hidenobu Soejima
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Science, Faculty of Medicine, Saga University, Nabeshima, Saga, Japan
| | - Kazuma Fujimoto
- Department of Internal Medicine, Faculty of Medicine, Saga University, Nabeshima, Saga, Japan
| | - Ryosuke Kimura
- Department of Human Biology and Anatomy, Faculty of Medicine, University of the Ryukyus, Nishihara-cho, Okinawa, Japan
| | - Hajime Ishida
- Department of Human Biology and Anatomy, Faculty of Medicine, University of the Ryukyus, Nishihara-cho, Okinawa, Japan
| | - Tsunehiko Hanihara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
- Department of Biological Structure, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan
| | - Akira Yasukouchi
- Department of Human Science, Faculty of Design, Kyushu University, Minami-ku Fukuoka, Japan
| | - Yoko Satta
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa, Japan
| | - Shigekazu Higuchi
- Department of Human Science, Faculty of Design, Kyushu University, Minami-ku Fukuoka, Japan
- * E-mail: (SH); (HO)
| | - Hiroki Oota
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
- Department of Biological Structure, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan
- * E-mail: (SH); (HO)
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Adamsson M, Laike T, Morita T. Annual variation in daily light exposure and circadian change of melatonin and cortisol concentrations at a northern latitude with large seasonal differences in photoperiod length. J Physiol Anthropol 2016; 36:6. [PMID: 27435153 PMCID: PMC4952149 DOI: 10.1186/s40101-016-0103-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 07/05/2016] [Indexed: 01/17/2023] Open
Abstract
Background Seasonal variations in physiology and behavior have frequently been reported. Light is the major zeitgeber for synchronizing internal circadian rhythms with the external solar day. Non-image forming effects of light radiation, for example, phase resetting of the circadian rhythms, melatonin suppression, and acute alerting effects, depend on several characteristics of the light exposure including intensity, timing and duration, spectral composition and previous light exposure, or light history. The aim of the present study was to report on the natural pattern of diurnal and seasonal light exposure and to examine seasonal variations in the circadian change of melatonin and cortisol concentrations for a group of Swedish office workers. Methods Fifteen subjects participated in a field study that was carried out in the south of Sweden. Ambulatory equipment was used for monthly measurements of the daily exposure to light radiation across the year. The measurements included illuminance and irradiance. The subjects collected saliva samples every 4 h during 1 day of the monthly measuring period. Results The results showed that there were large seasonal differences in daily amount of light exposure across the year. Seasonal differences were observed during the time periods 04:00–08:00, 08:00–12:00, 12:00–16:00, 16:00–20:00, and 20:00–24:00. Moreover, there were seasonal differences regarding the exposure pattern. The subjects were to a larger extent exposed to light in the afternoon/evening in the summer. During the winter, spring, and autumn, the subjects received much of the daily light exposure in the morning and early afternoon. Regarding melatonin, a seasonal variation was observed with a larger peak level during the winter and higher levels in the morning at 07:00. Conclusions This study adds to the results from other naturalistic studies by reporting on the diurnal and seasonal light exposure patterns for a group living at a northern latitude of 56° N, with large annual variations in photoperiod length. It seems to be seasonal variation in the lighting conditions, both concerning intensities as well as regarding the pattern of the light exposure to which people living at high latitudes are exposed which may result in seasonal variation in the circadian profile of melatonin.
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Affiliation(s)
- Mathias Adamsson
- School of Engineering, Jönköping University, P.O. Box 1026, SE-551 11, Jönköping, Sweden.
| | - Thorbjörn Laike
- Department of Architecture and Built Environment, Lund University, P.O. Box 118, SE-221 00, Lund, Sweden
| | - Takeshi Morita
- Department of Environmental Science, Fukuoka Women's University, 1-1-1 Kasumigaoka, Higashi-ku, Fukuoka, Japan
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Gubin DG, Weinert D. Deterioration of temporal order and circadian disruption with age 2: Systemic mechanisms of aging-related circadian disruption and approaches to its correction. ADVANCES IN GERONTOLOGY 2016. [DOI: 10.1134/s2079057016010057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Higuchi S, Lee SI, Kozaki T, Harada T, Tanaka I. Late circadian phase in adults and children is correlated with use of high color temperature light at home at night. Chronobiol Int 2016; 33:448-52. [PMID: 27010525 DOI: 10.3109/07420528.2016.1152978] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Light is the strongest synchronizer of human circadian rhythms, and exposure to residential light at night reportedly causes a delay of circadian rhythms. The present study was conducted to investigate the association between color temperature of light at home and circadian phase of salivary melatonin in adults and children. Twenty healthy children (mean age: 9.7 year) and 17 of their parents (mean age: 41.9 years) participated in the experiment. Circadian phase assessments were made with dim light melatonin onset (DLMO). There were large individual variations in DLMO both in adults and children. The average DLMO in adults and in children were 21:50 ± 1:12 and 20:55 ± 0:44, respectively. The average illuminance and color temperature of light at eye level were 139.6 ± 82.7 lx and 3862.0 ± 965.6 K, respectively. There were significant correlations between color temperature of light and DLMO in adults (r = 0.735, p < 0.01) and children (r = 0.479, p < 0.05), although no significant correlations were found between illuminance level and DLMO. The results suggest that high color temperature light at home might be a cause of the delay of circadian phase in adults and children.
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Affiliation(s)
- Shigekazu Higuchi
- a Department of Human Science, Faculty of Design , Kyushu University , Fukuoka , Japan.,b Physiological Anthropology Research Center , Kyushu University , Fukuoka , Japan
| | - Sang-il Lee
- a Department of Human Science, Faculty of Design , Kyushu University , Fukuoka , Japan
| | - Tomoaki Kozaki
- a Department of Human Science, Faculty of Design , Kyushu University , Fukuoka , Japan.,b Physiological Anthropology Research Center , Kyushu University , Fukuoka , Japan
| | - Tetsuo Harada
- c Laboratory of Environmental Physiology, Faculty of Education , Kochi University , Kochi , Japan
| | - Ikuo Tanaka
- a Department of Human Science, Faculty of Design , Kyushu University , Fukuoka , Japan
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Wieczorek J, Blazejczyk K, Morita T. Changes in melatonin secretion in tourists after rapid movement to another lighting zone without transition of time zone. Chronobiol Int 2016; 33:220-33. [DOI: 10.3109/07420528.2015.1130050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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23
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Auger RR, Burgess HJ, Emens JS, Deriy LV, Thomas SM, Sharkey KM. Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015: An American Academy of Sleep Medicine Clinical Practice Guideline. J Clin Sleep Med 2015; 11:1199-236. [PMID: 26414986 DOI: 10.5664/jcsm.5100] [Citation(s) in RCA: 206] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 08/19/2015] [Indexed: 01/28/2023]
Abstract
A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confidence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second- and first-tier degree of confidence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insufficient or absent data. Areas where further research is needed are discussed.
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Higuchi S, Nagafuchi Y, Lee SI, Harada T. Influence of light at night on melatonin suppression in children. J Clin Endocrinol Metab 2014; 99:3298-303. [PMID: 24840814 DOI: 10.1210/jc.2014-1629] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CONTEXT The sensitivity of melatonin to light suppression is expected to be higher in children because children have large pupils and pure crystal lenses. However, melatonin suppression by light in children remains unclear. OBJECTIVE We investigated whether light-induced melatonin suppression in children is larger than that in adults. METHODS Thirty-three healthy primary school children (mean age, 9.2 ± 1.5 y) and 29 healthy adults (mean age, 41.6 ± 4.7 y) participated in two experiments. In the first experiment, salivary melatonin concentrations in 13 children and 13 adults were measured at night under a dim light (<30 lux) and a moderately bright light (580 lux) in an experimental facility. Pupil diameters were also measured under dim light and bright light. In the second experiment, melatonin concentrations in 20 children and 16 adults were measured under dim light in the experimental facility and under room light at home (illuminance, 140.0 ± 82.7 lux). RESULTS In experiment 1, the melatonin concentration was significantly decreased by exposure to moderately bright light in both adults and children. Melatonin suppression was significantly larger in children (88.2%; n = 5) than in adults (46.3%; n = 6; P < .01), although the data for some participants were excluded because melatonin concentrations had not yet risen. In experiment 2, melatonin secretion was significantly suppressed by room light at home in children (n = 15; P < .05) but not in adults (n = 11). CONCLUSION We found that the percentage of melatonin suppression by light in children was almost twice that in adults, suggesting that melatonin is more sensitive to light in children than in adults at night.
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Affiliation(s)
- Shigekazu Higuchi
- Department of Human Science (S.H., Y.N., S.L.), Faculty of Design, Kyushu University, Fukuoka 815-8540, Japan; and Laboratory of Environmental Physiology (T.H.), Faculty of Education, Kochi University, Kochi 780-8520, Japan
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van de Werken M, Giménez MC, de Vries B, Beersma DGM, Gordijn MCM. Short-wavelength attenuated polychromatic white light during work at night: limited melatonin suppression without substantial decline of alertness. Chronobiol Int 2013; 30:843-54. [PMID: 23705821 DOI: 10.3109/07420528.2013.773440] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Exposure to light at night increases alertness, but light at night (especially short-wavelength light) also disrupts nocturnal physiology. Such disruption is thought to underlie medical problems for which shiftworkers have increased risk. In 33 male subjects we investigated whether short-wavelength attenuated polychromatic white light (<530 nm filtered out) at night preserves dim light melatonin levels and whether it induces similar skin temperature, alertness, and performance levels as under full-spectrum light. All 33 subjects participated in random order during three nights (at least 1 wk apart) either under dim light (3 lux), short-wavelength attenuated polychromatic white light (193 lux), or full-spectrum light (256 lux). Hourly saliva samples for melatonin analysis were collected along with continuous measurements of skin temperature. Subjective sleepiness and activation were assessed via repeated questionnaires and performance was assessed by the accuracy and speed of an addition task. Our results show that short-wavelength attenuated polychromatic white light only marginally (6%) suppressed salivary melatonin. Average distal-to-proximal skin temperature gradient (DPG) and its pattern over time remained similar under short-wavelength attenuated polychromatic white light compared with dim light. Subjects performed equally well on an addition task under short-wavelength attenuated polychromatic white light compared with full-spectrum light. Although subjective ratings of activation were lower under short-wavelength attenuated polychromatic white light compared with full-spectrum light, subjective sleepiness was not increased. Short-wavelength attenuated polychromatic white light at night has some advantages over bright light. It hardly suppresses melatonin concentrations, whereas performance is similar to the bright light condition. Yet, alertness is slightly reduced as compared with bright light, and DPG shows similarity to the dim light condition, which is a physiological sign of reduced alertness. Short-wavelength attenuated polychromatic white light might therefore not be advisable in work settings that require high levels of alertness.
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Affiliation(s)
- Maan van de Werken
- Department of Chronobiology, Centre for Life Sciences, University of Groningen, Groningen, The Netherlands.
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Kozaki T, Toda N, Noguchi H, Yasukouchi A. Effects of different light intensities in the morning on dim light melatonin onset. J Physiol Anthropol 2011; 30:97-102. [PMID: 21636952 DOI: 10.2114/jpa2.30.97] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The present study evaluated the effects of exposure to light intensity in the morning on dim light melatonin onset (DLMO). The tested light intensities were 750 lux, 150 lux, 3000 lux, 6000 lux and 12,000 lux (horizontal illuminance at cornea), using commercial 5000 K fluorescent lamps. Eleven healthy males aged 21-31 participated in 2-day experiments for each light condition. On the first experimental day (day 1), subjects were exposed to dim light (<30 lux) for 3 h in the morning (09:00-12:00). On the same day, saliva samples were taken in dim light (<30 lux) every 30 min from 21:00 to 01:00 to determine the DLMO phase. The subjects were allowed to sleep from 01:00 to 08:00. On the second experimental day (day 2), the subjects were exposed to experimental light conditions for 3 h in the morning. The experimental schedule after light exposure was the same as on day 1. On comparing day 2 with day 1, significant phase advances of DLMO were obtained at 3000 lux, 6000 lux and 12,000 lux. These findings indicate that exposure to a necessary intensity from an ordinary light source, such as a fluorescent lamp, in the morning within one day affects melatonin secretion.
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Parry BL, Meliska CJ, Sorenson DL, Lopez A, Martínez LF, Hauger RL, Elliott JA. Increased sensitivity to light-induced melatonin suppression in premenstrual dysphoric disorder. Chronobiol Int 2010; 27:1438-53. [PMID: 20795885 PMCID: PMC3038841 DOI: 10.3109/07420528.2010.503331] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Increased sensitivity to light-induced melatonin suppression characterizes some, but not all, patients with bipolar illness or seasonal affective disorder. The aim of this study was to test the hypothesis that patients with premenstrual dysphoric disorder (PMDD), categorized as a depressive disorder in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), have altered sensitivity to 200 lux light during mid-follicular (MF) and late-luteal (LL) menstrual cycle phases compared with normal control (NC) women. As an extension of a pilot study in which the authors administered 500 lux to 8 PMDD and 5 NC subjects, in the present study the authors administered 200 lux to 10 PMDD and 13 NC subjects during MF and LL menstrual cycle phases. Subjects were admitted to the General Clinical Research Center (GCRC) in dim light (<50 lux) to dark (during sleep) conditions at 16:00 h where nurses inserted an intravenous catheter at 17:00 h and collected plasma samples for melatonin at 30-min intervals from 18:00 to 10:00 h, including between 00:00 and 01:00 h for baseline values, between 01:30 and 03:00 h during the 200 lux light exposure administered from 01:00 to 03:00 h, and at 03:30 and 04:00 h after the light exposure. Median % melatonin suppression was significantly greater in PMDD (30.8%) versus NC (-0.2%) women (p = .040), and was significantly greater in PMDD in the MF (30.8%) than in the LL (-0.15%) phase (p = .047). Additionally, in the LL (but not the MF) phase, % suppression after 200 lux light was significantly positively correlated with serum estradiol level (p = .007) in PMDD patients, but not in NC subjects (p > .05).
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Affiliation(s)
- Barbara L Parry
- Department of Psychiatry, University of California, San Diego, La Jolla, California 92093-0804, USA.
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Ishibashi K, Arikura S, Kozaki T, Higuchi S, Yasukouchi A. THERMOREGULATORY EFFECT IN HUMANS OF SUPPRESSED ENDOGENOUS MELATONIN BY PRE-SLEEP BRIGHT-LIGHT EXPOSURE IN A COLD ENVIRONMENT. Chronobiol Int 2010; 27:782-806. [DOI: 10.3109/07420521003794069] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Thorne HC, Jones KH, Peters SP, Archer SN, Dijk DJ. Daily and Seasonal Variation in the Spectral Composition of Light Exposure in Humans. Chronobiol Int 2010; 26:854-66. [DOI: 10.1080/07420520903044315] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Kantermann T, Roenneberg T. Is light-at-night a health risk factor or a health risk predictor? Chronobiol Int 2009; 26:1069-74. [PMID: 19731106 DOI: 10.3109/07420520903223984] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In 2007, the IARC (WHO) has classified "shift-work that involves circadian disruption" as potentially carcinogenic. Ample evidence leaves no doubt that shift-work is detrimental for health, but the mechanisms behind this effect are not well understood. The hormone melatonin is often considered to be a causal link between night shift and tumor development. The underlying "light-at-night" (LAN) hypothesis is based on the following chain of arguments: melatonin is a hormone produced under the control of the circadian clock at night, and its synthesis can be suppressed by light; as an indolamine, it potentially acts as a scavenger of oxygen radicals, which in turn can damage DNA, which in turn can cause cancer. Although there is no experimental evidence that LAN is at the basis of increased cancer rates in shiftworkers, the scenario "light at night can cause cancer" influences research, medicine, the lighting industry and (via the media) also the general public, well beyond shiftwork. It is even suggested that baby-lights, TVs, computers, streetlights, moonlight, emergency lights, or any so-called "light pollution" by urban developments cause cancer via the mechanisms proposed by the LAN hypothesis. Our commentary addresses the growing concern surrounding light pollution. We revisit the arguments of the LAN theory and put them into perspective regarding circadian physiology, physical likelihood (e.g., what intensities reach the retina), and potential risks, specifically in non-shiftworkers.
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Affiliation(s)
- Thomas Kantermann
- Institute for Medical Psychology, University of Munich LMU, Munich, Germany
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Physiology and pharmacology of melatonin in relation to biological rhythms. Pharmacol Rep 2009; 61:383-410. [PMID: 19605939 DOI: 10.1016/s1734-1140(09)70081-7] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 05/01/2009] [Indexed: 01/01/2023]
Abstract
Melatonin is an evolutionarily conserved molecule that serves a time-keeping function in various species. In vertebrates, melatonin is produced predominantly by the pineal gland with a marked circadian rhythm that is governed by the central circadian pacemaker (biological clock) in the suprachiasmatic nuclei of the hypothalamus. High levels of melatonin are normally found at night, and low levels are seen during daylight hours. As a consequence, melatonin has been called the "darkness hormone". This review surveys the current state of knowledge regarding the regulation of melatonin synthesis, receptor expression, and function. In particular, it addresses the physiological, pathological, and therapeutic aspects of melatonin in humans, with an emphasis on biological rhythms.
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Smith MR, Eastman CI. Phase delaying the human circadian clock with blue-enriched polychromatic light. Chronobiol Int 2009; 26:709-25. [PMID: 19444751 DOI: 10.1080/07420520902927742] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The human circadian system is maximally sensitive to short-wavelength (blue) light. In a previous study we found no difference between the magnitude of phase advances produced by bright white versus bright blue-enriched light using light boxes in a practical protocol that could be used in the real world. Since the spectral sensitivity of the circadian system may vary with a circadian rhythm, we tested whether the results of our recent phase-advancing study hold true for phase delays. In a within-subjects counterbalanced design, this study tested whether bright blue-enriched polychromatic light (17000 K, 4000 lux) could produce larger phase delays than bright white light (4100 K, 5000 lux) of equal photon density (4.2x10(15) photons/cm(2)/sec). Healthy young subjects (n = 13) received a 2 h phase delaying light pulse before bedtime combined with a gradually delaying sleep/dark schedule on each of 4 consecutive treatment days. On the first treatment day the light pulse began 3 h after the dim light melatonin onset (DLMO). An 8 h sleep episode began at the end of the light pulse. Light treatment and the sleep schedule were delayed 2 h on each subsequent treatment day. A circadian phase assessment was conducted before and after the series of light treatment days to determine the time of the DLMO and DLMOff. Phase delays in the blue-enriched and white conditions were not significantly different (DLMO: -4.45+/-2.02 versus -4.48+/-1.97 h; DLMOff: -3.90+/-1.97 versus -4.35+/-2.39 h, respectively). These results indicate that at light levels commonly used for circadian phase shifting, blue-enriched polychromatic light is no more effective than the white polychromatic lamps of a lower correlated color temperature (CCT) for phase delaying the circadian clock.
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Affiliation(s)
- Mark R Smith
- Rush University Medical Center, Chicago, Illinois 60612, USA
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Figueiro MG, Bierman A, Bullough JD, Rea MS. A personal light-treatment device for improving sleep quality in the elderly: dynamics of nocturnal melatonin suppression at two exposure levels. Chronobiol Int 2009; 26:726-39. [PMID: 19444752 DOI: 10.1080/07420520902927809] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Light treatment has been used as a non-pharmacological tool to help mitigate poor sleep quality frequently found in older people. In order to increase compliance to non-pharmacological light treatments, new, more efficacious light-delivery systems need to be developed. A prototype personal light-treatment device equipped with low brightness blue light-emitting diodes (LEDs) (peak wavelength near 470 nm) was tested for its effectiveness in suppressing nocturnal melatonin, a measure of circadian stimulation. Two levels of corneal irradiance were set to deliver two prescribed doses of circadian light exposure. Eleven older subjects, between 51 and 80 yrs of age who met the selection criteria, were exposed to a high and a low level of light for 90 min on separate nights from the personal light-treatment device. Blood and saliva samples were collected at prescribed times for subsequent melatonin assay. After 1 h of light exposure, the light-induced nocturnal melatonin suppression level was about 35% for the low-light level and about 60% for the high-light level. The higher level of blue light suppressed melatonin more quickly, to a greater extent over the course of the 90 min exposure period, and maintained suppression after 60 min. The constant exposure of the low-light level resulted in a decrease in nocturnal melatonin suppression for the last sampling time, whereas for the high-light level, suppression continued throughout the entire exposure period. The present study performed with healthy adults suggests that the tested personal light-treatment device might be a practical, comfortable, and effective way to deliver light treatment to those suffering from circadian sleep disorders; however, the acceptance and effectiveness of personal light-treatment devices by older people and by other segments of the population suffering from sleep disorders in a real-life situation need to be directly tested.
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Affiliation(s)
- Mariana G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
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Portaluppi F, Touitou Y, Smolensky MH. Ethical and Methodological Standards for Laboratory and Medical Biological Rhythm Research. Chronobiol Int 2009; 25:999-1016. [PMID: 19005901 DOI: 10.1080/07420520802544530] [Citation(s) in RCA: 294] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Portaluppi F. Consistency and Accuracy of the Medical Subject Headings® Thesaurus for Electronic Indexing and Retrieval of Chronobiologic References. Chronobiol Int 2009; 24:1213-29. [DOI: 10.1080/07420520701791570] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Stevens RG. Light-at-night, circadian disruption and breast cancer: assessment of existing evidence. Int J Epidemiol 2009; 38:963-70. [PMID: 19380369 DOI: 10.1093/ije/dyp178] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Breast cancer incidence is increasing globally for largely unknown reasons. The possibility that a portion of the breast cancer burden might be explained by the introduction and increasing use of electricity to light the night was suggested >20 years ago. METHODS The theory is based on nocturnal light-induced disruption of circadian rhythms, notably reduction of melatonin synthesis. It has formed the basis for a series of predictions including that non-day shift work would increase risk, blind women would be at lower risk, long sleep duration would lower risk and community nighttime light level would co-distribute with breast cancer incidence on the population level. RESULTS Accumulation of epidemiological evidence has accelerated in recent years, reflected in an International Agency for Research on Cancer (IARC) classification of shift work as a probable human carcinogen (2A). There is also a strong rodent model in support of the light-at-night (LAN) idea. CONCLUSION If a consensus eventually emerges that LAN does increase risk, then the mechanisms for the effect are important to elucidate for intervention and mitigation. The basic understanding of phototransduction for the circadian system, and of the molecular genetics of circadian rhythm generation are both advancing rapidly, and will provide for the development of lighting technologies at home and at work that minimize circadian disruption, while maintaining visual efficiency and aesthetics. In the interim, there are strategies now available to reduce the potential for circadian disruption, which include extending the daily dark period, appreciate nocturnal awakening in the dark, using dim red light for nighttime necessities, and unless recommended by a physician, not taking melatonin tablets.
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Affiliation(s)
- Richard G Stevens
- Department of Community Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-6325, USA.
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Bartsch C, Bartsch H, Peschke E. Light, melatonin and cancer: current results and future perspectives 1. BIOL RHYTHM RES 2009. [DOI: 10.1080/09291010802066983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Turner PL, Mainster MA. Circadian photoreception: ageing and the eye's important role in systemic health. Br J Ophthalmol 2008; 92:1439-44. [PMID: 18757473 PMCID: PMC2582340 DOI: 10.1136/bjo.2008.141747] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To analyse how age-related losses in crystalline lens transmittance and pupillary area affect circadian photoreception and compare the circadian performance of phakic and pseudophakic individuals of the same age. METHODS The spectral sensitivity of circadian photoreception peaks in the blue part of the spectrum at approximately 460 nm. Photosensitive retinal ganglion cells send unconscious information about environmental illumination to non-visual brain centres including the human body's master biological clock in the suprachiasmatic nuclei. This information permits human physiology to be optimised and aligned with geophysical day-night cycles using neural and hormonal messengers including melatonin. Age-related transmittance spectra of crystalline lenses and photopic pupil diameter are used with the spectral sensitivity of melatonin suppression and the transmittance spectra of intraocular lenses (IOLs) to analyse how ageing and IOL chromophores affect circadian photoreception. RESULTS Ageing increases crystalline lens light absorption and decreases pupil area resulting in progressive loss of circadian photoreception. A 10-year-old child has circadian photoreception 10-fold greater than a 95-year-old phakic adult. A 45-year-old adult retains only half the circadian photoreception of early youth. Pseudophakia improves circadian photoreception at all ages, particularly with UV-only blocking IOLs which transmit blue wavelengths optimal for non-visual photoreception. CONCLUSIONS Non-visual retinal ganglion photoreceptor responses to bright, properly timed light exposures help assure effective circadian photoentrainment and optimal diurnal physiological processes. Circadian photoreception can persist in visually blind individuals if retinal ganglion cell photoreceptors and their suprachiasmatic connections are intact. Retinal illumination decreases with ageing due to pupillary miosis and reduced crystalline lens light transmission especially of short wavelengths. Inadequate environmental light and/or ganglion photoreception can cause circadian disruption, increasing the risk of insomnia, depression, numerous systemic disorders and possibly early mortality. Artificial lighting is dimmer and less blue-weighted than natural daylight, contributing to age-related losses in unconscious circadian photoreception. Optimal intraocular lens design should consider the spectral requirements of both conscious and unconscious retinal photoreception.
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Affiliation(s)
- P L Turner
- Department of Ophthalmology, University of Kansas School of Medicine, Prairie Village, KS 66208-3444, USA.
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Higuchi S, Ishibashi K, Aritake S, Enomoto M, Hida A, Tamura M, Kozaki T, Motohashi Y, Mishima K. Inter-individual difference in pupil size correlates to suppression of melatonin by exposure to light. Neurosci Lett 2008; 440:23-6. [DOI: 10.1016/j.neulet.2008.05.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 05/07/2008] [Accepted: 05/13/2008] [Indexed: 11/24/2022]
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Higuchi S, Motohashi Y, Ishibashi K, Maeda T. Influence of eye colors of Caucasians and Asians on suppression of melatonin secretion by light. Am J Physiol Regul Integr Comp Physiol 2007; 292:R2352-6. [PMID: 17332164 DOI: 10.1152/ajpregu.00355.2006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This experiment tested effects of human eye pigmentation depending on the ethnicity on suppression of nocturnal melatonin secretion by light. Ten healthy Caucasian males with blue, green, or light brown irises (light-eyed Caucasians) and 11 Asian males with dark brown irises (dark-eyed Asians) volunteered to participate in the study. The mean ages of the light-eyed Caucasians and dark-eyed Asians were 26.4 ± 3.2 and 25.3 ± 5.7 years, respectively. The subjects were exposed to light (1,000 lux) for 2 h at night. The starting time of exposure was set to 2 h before the time of peak salivary melatonin concentration of each subject, which was determined in a preliminary experiment. Salivary melatonin concentration and pupil size were measured before exposure to light and during exposure to light. The percentage of suppression of melatonin secretion by light was calculated. The percentage of suppression of melatonin secretion 2 h after the start of light exposure was significantly larger in light-eyed Caucasians (88.9 ± 4.2%) than in dark-eyed Asians (73.4 ± 20.0%) ( P < 0.01). No significant difference was found between pupil sizes in light-eyed Caucasians and dark-eyed Asians. These results suggest that sensitivity of melatonin to light suppression is influenced by eye pigmentation and/or ethnicity.
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Affiliation(s)
- Shigekazu Higuchi
- Department of Public Health, Akita University School of Medicine, Akita, Japan.
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