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Author Rahman, S.A.; St Hilaire, M.A.; Gronfier, C.; Chang, A.-M.; Santhi, N.; Czeisler, C.A.; Klerman, E.B.; Lockley, S.W.
Title Functional decoupling of melatonin suppression and circadian phase resetting in humans Type Journal Article
Year 2018 Publication The Journal of Physiology Abbreviated Journal J Physiol
Volume 596 Issue 11 Pages 2147-2157
Keywords Human Health
Abstract KEY POINTS: There is assumed to be a monotonic association between melatonin suppression and circadian phase resetting induced by light exposure. We tested the association between melatonin suppression and phase resetting in humans. Sixteen young healthy participants received nocturnal bright light ( approximately 9500 lux) exposure of continuous or intermittent patterns, and different durations ranging from 12 min to 6.5 h. Intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every bright light stimulus in an intermittent exposure pattern induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest that phase shifts and melatonin suppression are functionally independent such that one cannot be used as a proxy measure of the other. ABSTRACT: Continuous experimental light exposures show that, in general, the conditions that produce greater melatonin suppression also produce greater phase shift, leading to the assumption that one can be used as a proxy for the other. We tested this association in 16 healthy individuals who participated in a 9-day inpatient protocol by assessing melatonin suppression and phase resetting in response to a nocturnal light exposure (LE) of different patterns: (i) dim-light control (<3 lux; n = 6) or (ii) two 12-min intermittent bright light pulses (IBL) separated by 36 min of darkness ( approximately 9500 lux; n = 10). We compared these results with historical data from additional LE patterns: (i) dim-light control (<3 lux; n = 11); (ii) single continuous bright light exposure of 12 min (n = 9), 1.0 h (n = 10) or 6.5 h (n = 6); or (iii) an IBL light pattern consisting of six 15-min pulses with 1.0 h dim-light recovery intervals between them during a total of 6.5 h (n = 7). All light exposure groups had significantly greater phase-delay shifts than the dim-light control condition (P < 0.0001). While a monotonic association between melatonin suppression and circadian phase shift was observed, intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every IBL stimulus induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest unique specificities in how light-induced phase shifts and melatonin suppression are mediated such that one cannot be used as a proxy measure of the other.
Address Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3751 ISBN Medium
Area Expedition Conference
Notes (down) PMID:29707782 Approved no
Call Number GFZ @ kyba @ Serial 1887
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Author Madahi, P.-G.; Ivan, O.; Adriana, B.; Diana, O.; Carolina, E.
Title Constant light during lactation programs circadian and metabolic systems Type Journal Article
Year 2018 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 35 Issue 8 Pages 1153-1167
Keywords Animals
Abstract Exposure to light at night is a disruptive condition for the adult circadian system, leading to arrhythmicity in nocturnal rodents. Circadian disruption is a risk factor for developing physiological and behavioral alterations, including weight gain and metabolic disease. During early stages of development, the circadian system undergoes a critical period of adjustment, and it is especially vulnerable to altered lighting conditions that may program its function, leading to long-term effects. We hypothesized that during lactation a disrupted light-dark cycle due to light at night may disrupt the circadian system and in the long term induce metabolic disorders. Here we explored in pups, short- and long-term effects of constant light (LL) during lactation. In the short term, LL caused a loss of rhythmicity and a reduction in the immunopositive cells of VIP, AVP, and PER1 in the suprachiasmatic nucleus (SCN). In the short term, the affection on the circadian clock in the pups resulted in body weight gain, loss of daily rhythms in general activity, plasma glucose and triglycerides (TG). Importantly, the DD conditions during development also induced altered daily rhythms in general activity and in the SCN. Exposure to LD conditions after lactation did not restore rhythmicity in the SCN, and the number of immunopositve cells to VIP, AVP, and PER1 remained reduced. In the long term, daily rhythmicity in general activity was restored; however, daily rhythms in glucose and TG remained disrupted, and daily mean levels of TG were significantly increased. Present results point out the programming role played by the LD cycle during early development in the function of the circadian system and on metabolism. This study points out the risk represented by exposure to an altered light-dark cycle during early stages of development. ABBREVIATIONS: AVP: arginine vasopressin peptide; CRY: cryptochrome; DD: constant darkness; DM: dorsomedial; LD: light-dark cycle; LL: constant light; NICUs: neonatal intensive care units; P: postnatal days; PER: period; S.E.M.: standard error of the mean; SCN: suprachiasmatic nucleus; TG: triglycerides; VIP: vasointestinal peptide; VL: ventrolateral; ZT: zeitgeber time.
Address a Facultad de Medicina , Universidad Nacional Autonoma de Mexico, UNAM , Mexico City , Mexico
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0742-0528 ISBN Medium
Area Expedition Conference
Notes (down) PMID:29688088 Approved no
Call Number GFZ @ kyba @ Serial 1884
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Author Garcia-Saenz, A.; Sanchez de Miguel, A.; Espinosa, A.; Valentin, A.; Aragones, N.; Llorca, J.; Amiano, P.; Martin Sanchez, V.; Guevara, M.; Capelo, R.; Tardon, A.; Peiro-Perez, R.; Jimenez-Moleon, J.J.; Roca-Barcelo, A.; Perez-Gomez, B.; Dierssen-Sotos, T.; Fernandez-Villa, T.; Moreno-Iribas, C.; Moreno, V.; Garcia-Perez, J.; Castano-Vinyals, G.; Pollan, M.; Aube, M.; Kogevinas, M.
Title Evaluating the Association between Artificial Light-at-Night Exposure and Breast and Prostate Cancer Risk in Spain (MCC-Spain Study) Type Journal Article
Year 2018 Publication Environmental Health Perspectives Abbreviated Journal Environ Health Perspect
Volume 126 Issue 4 Pages 047011
Keywords Human Health; Remote Sensing; Adult; Aged; Aged, 80 and over; Breast Neoplasms/*epidemiology/etiology; Case-Control Studies; Circadian Rhythm; Female; Humans; Incidence; Light/*adverse effects; Lighting/*adverse effects; Male; Middle Aged; Prostatic Neoplasms/*epidemiology/etiology; Risk Factors; Spain/epidemiology; Young Adult
Abstract BACKGROUND: Night shift work, exposure to light at night (ALAN) and circadian disruption may increase the risk of hormone-dependent cancers. OBJECTIVES: We evaluated the association of exposure to ALAN during sleeping time with breast and prostate cancer in a population based multicase-control study (MCC-Spain), among subjects who had never worked at night. We evaluated chronotype, a characteristic that may relate to adaptation to light at night. METHODS: We enrolled 1,219 breast cancer cases, 1,385 female controls, 623 prostate cancer cases, and 879 male controls from 11 Spanish regions in 2008-2013. Indoor ALAN information was obtained through questionnaires. Outdoor ALAN was analyzed using images from the International Space Station (ISS) available for Barcelona and Madrid for 2012-2013, including data of remotely sensed upward light intensity and blue light spectrum information for each geocoded longest residence of each MCC-Spain subject. RESULTS: Among Barcelona and Madrid participants with information on both indoor and outdoor ALAN, exposure to outdoor ALAN in the blue light spectrum was associated with breast cancer [adjusted odds ratio (OR) for highest vs. lowest tertile, OR=1.47; 95% CI: 1.00, 2.17] and prostate cancer (OR=2.05; 95% CI: 1.38, 3.03). In contrast, those exposed to the highest versus lowest intensity of outdoor ALAN were more likely to be controls than cases, particularly for prostate cancer. Compared with those who reported sleeping in total darkness, men who slept in “quite illuminated” bedrooms had a higher risk of prostate cancer (OR=2.79; 95% CI: 1.55, 5.04), whereas women had a slightly lower risk of breast cancer (OR=0.77; 95% CI: 0.39, 1.51). CONCLUSION: Both prostate and breast cancer were associated with high estimated exposure to outdoor ALAN in the blue-enriched light spectrum. https://doi.org/10.1289/EHP1837.
Address IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0091-6765 ISBN Medium
Area Expedition Conference
Notes (down) PMID:29687979; PMCID:PMC6071739 Approved no
Call Number GFZ @ kyba @ Serial 3044
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Author Sanders, D.; Gaston, K.J.
Title How ecological communities respond to artificial light at night Type Journal Article
Year 2018 Publication Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology Abbreviated Journal J Exp Zool A Ecol Integr Physiol
Volume 329 Issue 8-9 Pages 394-400
Keywords Ecology
Abstract Many ecosystems worldwide are exposed to artificial light at night (ALAN), from streetlights and other sources, and a wide range of organisms has been shown to respond to this anthropogenic pressure. This raises concerns about the consequences for major ecosystem functions and their stability. However, there is limited understanding of how whole ecological communities respond to ALAN, and this cannot be gained simply by making predictions from observed single species physiological, behavioral, or ecological responses. Research needs to include an important building block of ecological communities, namely the interactions between species that drive ecological and evolutionary processes in ecosystems. Here, we summarize current knowledge about community responses to ALAN and illustrate different pathways and their impact on ecosystem functioning and stability. We discuss that documentation of the impact of ALAN on species interaction networks and trait distributions provides useful tools to link changes in community structure to ecosystem functions. Finally, we suggest several approaches to advance research that will link the diverse impact of ALAN to changes in ecosystems.
Address Wissenschaftskolleg zu Berlin, Institute for Advanced Study, Berlin, Germany
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2471-5638 ISBN Medium
Area Expedition Conference
Notes (down) PMID:29656458 Approved no
Call Number GFZ @ kyba @ Serial 1857
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Author Buonfiglio, D.; Parthimos, R.; Dantas, R.; Cerqueira Silva, R.; Gomes, G.; Andrade-Silva, J.; Ramos-Lobo, A.; Amaral, F.G.; Matos, R.; Sinesio, J.J.; Motta-Teixeira, L.C.; Donato, J.J.; Reiter, R.J.; Cipolla-Neto, J.
Title Melatonin Absence Leads to Long-Term Leptin Resistance and Overweight in Rats Type Journal Article
Year 2018 Publication Frontiers in Endocrinology Abbreviated Journal Front Endocrinol (Lausanne)
Volume 9 Issue Pages 122
Keywords Human health
Abstract Melatonin (Mel), a molecule that conveys photoperiodic information to the organisms, is also involved in the regulation of energy homeostasis. Mechanisms of action of Mel in the energy balance remain unclear; herein we investigated how Mel regulates energy intake and expenditure to promote a proper energy balance. Male Wistar rats were assigned to control, control + Mel, pinealectomized (PINX) and PINX + Mel groups. To restore a 24-h rhythm, Mel (1 mg/kg) was added to the drinking water exclusively during the dark phase for 13 weeks. After this treatment period, rats were subjected to a 24-h fasting test, an acute leptin responsiveness test and cold challenge. Mel treatment reduced food intake, body weight, and adiposity. When challenged to 24-h fasting, Mel-treated rats also showed reduced hyperphagia when the food was replaced. Remarkably, PINX rats exhibited leptin resistance; this was likely related to the capacity of leptin to affect body weight, food intake, and hypothalamic signal-transducer and activator of transcription 3 phosphorylation, all of which were reduced. Mel treatment restored leptin sensitivity in PINX rats. An increased hypothalamic expression of agouti-related peptide (Agrp), neuropeptide Y, and Orexin was observed in the PINX group while Mel treatment reduced the expression of Agrp and Orexin. In addition, PINX rats presented lower UCP1 protein levels in the brown adipose tissue and required higher tail vasoconstriction to get a proper thermogenic response to cold challenge. Our findings reveal a previously unrecognized interaction of Mel and leptin in the hypothalamus to regulate the energy balance. These findings may help to explain the high incidence of metabolic diseases in individuals exposed to light at night.
Address Department of Physiology and Biophysics, Institute of Biomedical Sciences-I, University of Sao Paulo (USP), Sao Paulo, Brazil
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-2392 ISBN Medium
Area Expedition Conference
Notes (down) PMID:29636725; PMCID:PMC5881424 Approved no
Call Number NC @ ehyde3 @ Serial 2093
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