Cited by 338Sleep and Wakefulness ResearchCircadian rhythm and melatoninSleep and Work-Related Fatigue

IL-6 and its circadian secretion in humans

Vgontzas, A.N., Bixler, E.O., Lin, H.-M., Prolo, P., Trakada, G., Chrousos, G.P.·2005·Neuroimmunomodulation

Abstract

Interleukin-6 (IL-6) is a pleiotropic cytokine produced by numerous types of immune and nonimmune cells and is involved in many pathophysiologic mechanisms in humans. Many studies suggest that IL-6 is a putative ‘sleep factor’ and its circadian secretion correlates with sleep/sleepiness. IL-6 is elevated in disorders of excessive daytime sleepiness such as narcolepsy and obstructive sleep apnea. It correlates positively with body mass index and may be a mediator of sleepiness in obesity. Also the secretion of this cytokine is stimulated by total acute or partial short-term sleep loss reflecting the increased sleepiness experienced by sleep-deprived individuals. Studies that evaluated the 24-hour secretory pattern of IL-6 in healthy young adults suggest that IL-6 is secreted in a biphasic circadian pattern with two nadirs at about 08.00 and 21.00, and two zeniths at about 19.00 and 05.00 h. In contrast, following sleep deprivation or in disorders of sleep disturbance, e.g., insomnia, IL-6 peaks during the day and, based on the level of stress system activity, i.e., cortisol secretion, contributes to either sleepiness and deep sleep (low cortisol) or feelings of tiredness and fatigue and poor sleep (high cortisol). In order to address concerns about the potential impact of differences of IL-6 levels between the beginning and the end of the 24-hour blood-drawing experiment, we proceeded with a cosinor analysis of ‘detrended’ data in young and old healthy individuals. This new analysis did not affect the biphasic circadian pattern of IL-6 secretion in young adults, while it augmented the flattened circadian pattern in old individuals in whom the difference was greater. Finally, IL-6 appears to be somnogenic in rats and exhibits a diurnal rhythm that follows the sleep/wake cycle in these animals. We conclude that IL-6 is a mediator of sleepiness and its circadian pattern reflects the homeostatic drive for sleep.

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Crossref · 10.1159/000084844

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Authors
Vgontzas, A. N., Bixler, E. O., Lin, H.-M., Prolo, P., Trakada, G., & Chrousos, G. P.
Affiliations
  • Pennsylvania State University (US)
  • University of California, Los Angeles (US)
  • National Institutes of Health (US)
Venue
Neuroimmunomodulation
Publisher
S. Karger AG
Published
2005
Volume
12
Issue
3
Pages
131-140
ISSN
  • 1021-7401 (ISSN-L)
  • 1423-0216
OpenAlex
W1970138464
Cited by
338
References
47
Citations by year
2026: 9 · 2025: 18 · 2024: 10 · 2023: 20 · 2022: 14 · 2021: 7 · 2020: 19 · 2019: 22 · 2018: 12 · 2017: 19 · 2016: 16 · 2015: 14 · 2014: 10 · 2013: 17 · 2012: 20
FWCI
1.96
Type
journal article
Language
en
Open access
closed
Locations
  • NeuroImmunoModulation (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Sleep and Wakefulness Research
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
Keywords
interleukin-6, circadian rhythm, sleepiness, sleep deprivation, narcolepsy, obstructive sleep apnea, obesity, insomnia, cortisol, aging, cosinor analysis, sleep homeostasis, rats
MeSH terms
Aging, Animals, Circadian Rhythm, Homeostasis, Humans, Hydrocortisone, Sleep, Sleep Wake Disorders, Species Specificity, Interleukin-6, Up-Regulation

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