Circadian and Homeostatic Regulation of Human Sleep and Cognitive Performance and Its Modulation by PERIOD3

Nasal solitary chemosensory cells govern daily rhythm in mouse model of allergic rhinitis

BACKGROUND

While the daily rhythm of allergic rhinitis (AR) has long been recognized, the molecular mechanism underlying this phenomenon remains enigmatic.

OBJECTIVE

We aimed to investigate the role of circadian clock in AR development and to clarify the mechanism by which the daily rhythm of AR is generated.

METHODS

AR was induced in mice with ovalbumin. Toluidine blue staining, liquid chromatography-tandem mass spectrometry analysis, real-time quantitative PCR, and immunoblotting were performed with AR and control mice.

RESULTS

Ovalbumin-induced AR is diurnally rhythmic and associated with clock gene disruption in nasal mucosa. In particular, Rev-erbα is generally downregulated and its rhythm retained, but with a near-12-hour phase shift. Furthermore, global knockout of core clock gene Bmal1 or Rev-erbα increases the susceptibility of mice to AR and blunts AR rhythmicity. Importantly, nasal solitary chemosensory cells (SCCs) are rhythmically activated, and inhibition of the SCC pathway leads to attenuated AR and a loss of its rhythm. Moreover, rhythmic activation of SCCs is accounted for by diurnal expression of ChAT (an enzyme responsible for the synthesis of acetylcholine) and temporal generation of the neurotransmitter acetylcholine. Mechanistically, Rev-erbα trans-represses Chat through direct binding to a specific response element, generating a diurnal oscillation in this target gene.

CONCLUSION

SCCs, under the control of Rev-erbα, are a driver of AR rhythmicity; targeting SCCs should be considered as a new avenue for AR management.

Disrupted Circadian Rhythms and Substance Use Disorders: A Narrative Review

Substance use disorder is a major global health concern, with a high prevalence among adolescents and young adults. The most common substances of abuse include alcohol, marijuana, cocaine, nicotine, and opiates. Evidence suggests that a mismatch between contemporary lifestyle and environmental demands leads to disrupted circadian rhythms that impair optimal physiological and behavioral function, which can increase the vulnerability to develop substance use disorder and related problems. The circadian system plays an important role in regulating the sleep-wake cycle and reward processing, both of which directly affect substance abuse. Distorted substance use can have a reciprocal effect on the circadian system by influencing circadian clock gene expression. Considering the detrimental health consequences and profound societal impact of substance use disorder, it is crucial to comprehend its complex association with circadian rhythms, which can pave the way for the generation of novel chronotherapeutic treatment approaches. In this narrative review, we have explored the potential contributions of disrupted circadian rhythms and sleep on use and relapse of different substances of abuse. The involvement of circadian clock genes with drug reward pathways is discussed, along with the potential research areas that can be explored to minimize disordered substance use by improving circadian hygiene.

Greater within- and between-day instability is associated with worse anxiety and depression symptoms

BACKGROUND

Depression and anxiety affect hundreds of millions of people worldwide, and their prevalence increased during the COVID-19 pandemic as social schedules were disrupted. This study explores the associations between anxiety and depression and within- and between-day instability of affective, somatic, and cognitive symptoms during the early pandemic stages.

METHODS

Participants (n = 153, ages 18-77, 72 % female) reported daily levels of affective (anxiety/sadness), somatic (appetite/sleepiness), and cognitive (concentration/energy) symptoms for 14-44 days at five timepoints: 0, 3, 6, 9, and 12 h after awakening. At the end of the study, participants completed validated scales for anxiety (GAD-7) and depression (PHQ-9). Symptom instability was assessed using the Absolute Real Variability (ARV) index. Regression models examined within-day instability (WD-I) and between-day instability (BD-I) with GAD-7 and PHQ-9 scores as outcomes.

RESULTS

Greater instability (both WD-I and BD-I) of affective symptoms correlated with elevated GAD-7 and PHQ-9 scores. For somatic and cognitive symptoms, greater BD-I was associated with higher scores.

LIMITATIONS

The study used retrospective daily data, which could benefit from real-time assessments for improved accuracy.

CONCLUSIONS

This study provides empirical evidence of a connection between greater anxiety and depression severity and increased instability in daily mood and physiological symptoms. The findings underscore the importance of consistent symptom monitoring to understand overall mental health trajectories. Additionally, it highlights the role of daily routines in stabilizing the circadian system, potentially regulating physiological and psychological processes and reducing symptom instability.

Sleep and home parenteral nutrition in adults: A narrative review

Infusions of home parenteral nutrition (HPN) are often cycled at night coinciding with sleep episodes. Adult consumers of HPN are known to experience poor sleep attributed to frequent awakenings and long durations of wakefulness after falling asleep. Consequently, most consumers do not meet recommendations for sleep duration and quality or daytime napping. The primary underlying pathophysiology resulting in sleep problems is nocturia; however, other factors also exist, including disruptions caused by medical equipment (ie, pump alarms), comorbid conditions, dysglycemia, and medication use. Early guidance on sleep is imperative because of the central role of sleep in physical health and wellbeing, including mitigating complications, such as infection risk, gastrointestinal problems, pain sensitivity, and fatigue. Clinicians should routinely inquire about the sleep of their patients and address factors known to perturb sleep. Nonpharmacologic opportunities to mitigate sleep problems include education on healthy sleep practices (ie, sleep hygiene); changes in infusion schedules, volumes, rates, and equipment; and, possibly, behavioral interventions, which have yet to be examined in this population. Addressing comorbid conditions, such as mood disorders, and nutrition deficiencies may also help. Pharmacologic interventions and technological advancement in HPN delivery are also needed. Research on sleep in this population is considered a priority, yet it remains limited at this time.

Sleep Delta power, age, and sex effects in treatment-resistant depression

Electroencephalographic (EEG) deficits in slow wave activity or Delta power (0.5-4 Hz) indicate disturbed sleep homeostasis and are hallmarks of depression. Sleep homeostasis is linked to restorative sleep and potential antidepressant response via non-rapid eye movement (NREM) slow wave sleep (SWS) during which neurons undergo essential repair and rejuvenation. Decreased Low Delta power (0.5-2 Hz) was previously reported in individuals with depression. This study investigated power levels in the Low Delta (0.5-<2 Hz), High Delta (2-4 Hz), and Total Delta (0.5-4 Hz) bands and their association with age, sex, and disrupted sleep in treatment-resistant depression (TRD). Mann-Whitney U tests were used to compare the nightly progressions of Total Delta, Low Delta, and High Delta in 100 individuals with TRD and 24 healthy volunteers (HVs). Polysomnographic parameters were also examined, including Total Sleep Time (TST), Sleep Efficiency (SE), and Wake after Sleep Onset (WASO). Individuals with TRD had lower Delta power during the first NREM episode (NREM1) than HVs. The deficiency was observed in the Low Delta band versus High Delta. Females with TRD had higher Delta power than males during the first NREM1 episode, with the most noticeable sex difference observed in Low Delta. In individuals with TRD, Low Delta power correlated with WASO and SE, and High Delta correlated with WASO. Low Delta power deficits in NREM1 were observed in older males with TRD, but not females. These results provide compelling evidence for a link between age, sex, Low Delta power, sleep homeostasis, and non-restorative sleep in TRD.

Postoperative cognitive dysfunction: spotlight on light, circadian rhythms, and sleep

Postoperative cognitive dysfunction (POCD) is a neurological disorder characterized by the emergence of cognitive impairment after surgery. A growing body of literature suggests that the onset of POCD is closely tied to circadian rhythm disruption (CRD). Circadian rhythms are patterns of behavioral and physiological change that repeat themselves at approximately, but not exactly, every 24 h. They are entrained to the 24 h day by the daily light-dark cycle. Postoperative CRD affects cognitive function likely by disrupting sleep architecture, which in turn provokes a host of pathological processes including neuroinflammation, blood-brain barrier disturbances, and glymphatic pathway dysfunction. Therefore, to address the pathogenesis of POCD it is first necessary to correct the dysregulated circadian rhythms that often occur in surgical patients. This narrative review summarizes the evidence for CRD as a key contributor to POCD and concludes with a brief discussion of how circadian-effective hospital lighting can be employed to re-entrain stable and robust circadian rhythms in surgical patients.

The administration of rhBmal1 reduces sleep deprivation-induced anxiety and cognitive impairment in mice

BACKGROUND

In mammals, circadian rhythms control metabolism, immunological response and reproductive processes. Bmal1 (brain and muscle Arnt-like protein-1) is a key element in the regulation of circadian rhythms.

METHODS

This investigation explores the pathophysiological effects of sleep deprivation in a mouse model as well as the potential underlying mechanisms. A mouse sleep deprivation model was constructed using a modified multi-platform water environment method. The anxiety-like behaviours of mice were assessed by the open field test and elevated plus maze, and the cognitive function of mice was tested by the nest-building test. The expression levels of targeted genes were determined by Western blotting assay and RT-qPCR assay.

RESULTS

We found that sleep deprivation profoundly enhanced anxiety levels and impaired cognitive function in mice. Sleep deprivation also reduced the expression levels of Bmal1 and BDNF (brain-derived neurotrophic factor) and increased oxidative stress in the hippocampus of mice. The intraperitoneal injection of human recombinant rhBmal1 protein alleviated sleep deprivation-induced anxiety and cognitive impairment, restored Bmal1 and BDNF levels, and reduced oxidative stress in the hippocampus of mice.

CONCLUSIONS

rhBmal1 treatment might serve as a potential therapy for mitigating sleep deprivation-related unfavourable symptoms.

The Associations between the Homeostatic and Circadian Sleep Processes and the Neurobehavioral Functioning (NBF) of Individuals with ADHD-A Systematic Review

The objective of the present review was to systematically examine associations between perturbations of the homeostatic or circadian sleep processes and the neurobehavioral functioning (NBF) of individuals with ADHD. Electronic databases were searched for articles published between December 2013 and March 2023. Studies were included if they used objective measures of NBF, used objective or subjective measures of sleep, and focused on individuals with ADHD. Ten studies met these inclusion criteria. Of these, eight studies found perturbations in the interplay between NBF and Process S or Process C, and three studies did not. The quality of the studies was degraded because they failed to address key factors that affect the sleep processes and by the presence of methodological weaknesses. Our review suggests that homeostatic and circadian sleep processes are associated with NBF in individuals with ADHD. However, to confirm the validity of this conclusion, future studies should examine or control for confounders and utilize experimental designs that allow causality to be inferred.

Sleep Patterns, Eating Behavior and the Risk of Noncommunicable Diseases

Sleep is extremely important for the homeostasis of the organism. In recent years, various studies have been carried out to address factors related to sleep patterns and their influence on food choices, as well as on the onset of chronic noncommunicable diseases. The aim of this article is to provide a scientific literature review on the possible role of sleep patterns on eating behavior and the risk of noncommunicable diseases. A search was performed on Medline (PubMed interface) using several keywords (e.g., "Factors Influencing Sleep" OR "Sleep and Chronic Diseases"). Articles published between 2000 and the present date that relate sleep to cyclic metabolic processes and changes in eating behavior were selected. Changes in sleep patterns are increasingly detected today, and these modifications are mainly caused by work and lifestyle conditions as well as a growing dependence on electronic devices. Sleep deprivation and the resultant short sleep duration lead to an increased appetite via an increase in the hunger hormone (ghrelin) and a decrease in the satiety hormone (leptin). Nowadays, sleep is undervalued, and thus often impaired, with consequences for the performance of various body systems. Sleep deprivation alters physiological homeostasis and influences eating behavior as well as the onset of chronic diseases.

Circadian functioning of Locus Cœruleus of the nocturnal rat and diurnal rodent Arvicanthis

The noradrenergic Locus Cœruleus is one of the major arousal structures involved in inducing wakefulness. While brain noradrenaline (NA) amounts display 24-h variations, the origin of NA rhythm is currently unknown. In this study, we tested the hypothesis that NA rhythm could result from its rhythmic synthesis. Therefore, we investigated the 24-h expression profile of NA rate-limiting enzyme, tyrosine hydroxylase (th), in the Locus Cœruleus (LC) of the nocturnal rat and the diurnal rodent Arvicanthis, under 12 h:12 h light/dark (LD) and constant darkness (DD) conditions. In both species, th mRNA levels vary significantly over 24-h. In nocturnal rats, th mRNA profiles show a unimodal rhythm, with peak values in late day in LD, and in the middle of the subjective day in DD. In contrast, th mRNA rhythm in Arvicanthis is characterized by a bimodal profile, with higher levels at the beginning of the day and of the night in LD, and in the middle of the subjective day and night in DD. The rhythmic pattern of th expression may be dependent on a LC clock machinery. Therefore, we investigated the expression of three clock genes, namely bmal1, per1, and per2, and found that their mRNAs display significant variations between day and nighttime points in both species, but in opposite directions. These data show that NA rhythm may be related to circadian expression of th gene in both species, but differs between nocturnal and diurnal rodents. Furthermore, the phase opposition of clock gene expression in the rat compared to Arvicanthis suggests that the clock machinery might be one of the mechanisms involved in th rhythmic expression.

Genomic heterogeneity affects the response to Daylight Saving Time

Circadian clocks control the timing of many physiological events in the 24-h day. When individuals undergo an abrupt external shift (e.g., change in work schedule or travel across multiple time zones), circadian clocks become misaligned with the new time and may take several days to adjust. Chronic circadian misalignment, e.g., as a result of shift work, has been shown to lead to several physical and mental health problems. Despite the serious health implications of circadian misalignment, relatively little is known about how genetic variation affects an individual's ability to entrain to abrupt external changes. Accordingly, we used the one-hour advance from the onset of daylight saving time (DST) as a natural experiment to comprehensively study how individual heterogeneity affects the shift of sleep/wake cycles in response to an abrupt external time change. We found that individuals genetically predisposed to a morning tendency adjusted to the advance in a few days, while genetically predisposed evening-inclined individuals had not shifted. Observing differential effects by genetic disposition after a one-hour advance underscores the importance of heterogeneity in adaptation to external schedule shifts. These genetic differences may affect how individuals adjust to jet lag or shift work as well.

Cognitive brain responses during circadian wake-promotion: evidence for sleep-pressure-dependent hypothalamic activations

The two-process model of sleep-wake regulation posits that sleep-wake-dependent homeostatic processes interact with the circadian timing system to affect human behavior. The circadian timing system is fundamental to maintaining stable cognitive performance, as it counteracts growing homeostatic sleep pressure during daytime. Using magnetic resonance imaging, we explored brain responses underlying working memory performance during the time of maximal circadian wake-promotion under varying sleep pressure conditions. Circadian wake-promoting strength was derived from the ability to sleep during an evening nap. Hypothalamic BOLD activity was positively linked to circadian wake-promoting strength under normal, but not under disproportionally high or low sleep pressure levels. Furthermore, higher hypothalamic activity under normal sleep pressure levels predicted better performance under sleep loss. Our results reappraise the two-process model by revealing a homeostatic-dose-dependent association between circadian wake-promotion and cognition-related hypothalamic activity.

Epidemiology of sleep and sleep disorders in The Netherlands

OBJECTIVE

There is a surging public interest in The Netherlands concerning sleep, sleep disorders and associated health. For a proper perspective, it is necessary to have reliable information on the prevalence of sleep characteristics at the national level. This study set out to assess prevalence rates and key characteristics of sleep and sleep disorders in The Netherlands.

METHODS

In 2012, a nationally representative sample of 2089 individuals, aged 18-70 years, responded to a set of 48 questions, including the Holland Sleep Disorders Questionnaire, a validated questionnaire based on the International Classification of Sleep Disorders.

RESULTS

Prevalence rates were: 32.1% for a general sleep disturbance (GSD), 43.2% for insufficient sleep, 8.2 for insomnia, 5.3% for circadian rhythm sleep disorder, 6.1% for parasomnia, 5.9% for hypersomnolence, 12.5% for restless legs disorder and limb movements during sleep, 7.1% for sleep related breathing disorder, and 12.2% for the presence of comorbidity, ie, the presence of two or more concurrent sleep disorders. In addition, sleep onset time as well as sleep duration showed U-shaped relationships with GSD prevalence rates, with respectively the 22:00-24:00 period and seven to 8 h as optimal associates.

CONCLUSIONS

Sleep disorders and insufficient sleep have a high prevalence. As matter of concern, female adolescents reached the highest prevalence rates for most sleep disorders, insufficient sleep and daytime malfunctioning.

Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation

Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER3 (5/5) ) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER3 (4/4) ). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability.

Sleep ability mediates individual differences in the vulnerability to sleep loss: evidence from a PER3 polymorphism

Sleep deprivation is highly prevalent in our 24/7 society with harmful consequences on daytime functioning on the individual level. Genetically determined, trait-like vulnerability contributes to prominent inter-individual variability in the behavioral responses to sleep loss and adverse circadian phase. We aimed at investigating the effects of differential sleep pressure levels (high vs low) on the circadian modulation of neurobehavioral performance, sleepiness correlates, and nap sleep in individuals genotyped for a polymorphism in the clock gene PERIOD3. Fourteen homozygous long (PER3(5/5)) and 15 homozygous short (PER3(4/4)) allele carriers underwent both a 40-h sleep deprivation and multiple nap protocol under controlled laboratory conditions. We compared genotypes regarding subjective and ocular correlates of sleepiness, unintentional sleep episodes as well as psychomotor vigilance during both protocols. Nap sleep was monitored by polysomnography and visually scored according to standard criteria. The detrimental effects of high sleep pressure on sleepiness correlates and psychomotor vigilance were more pronounced in PER3(5/5) than PER3(4/4) carriers. Under low sleep pressure, both groups showed similar circadian time courses. Concomitantly, nap sleep efficiency and subjective sleep quality across all naps tended to be higher in the more vulnerable PER3(5/5) carriers. In addition, PER3-dependent sleep-loss-related attentional lapses were mediated by sleep efficiency across the circadian cycle. Our data corroborate a greater detrimental impact of sleep deprivation in PER3(5/5) compared to PER3(4/4) carriers. They further suggest that the group with greater attentional performance impairment due to sleep deprivation (PER3(5/5) carriers) is superior at initiating sleep over the 24-h cycle. This higher sleep ability may mirror a faster sleep pressure build-up between the multiple sleep opportunities and thus a greater flexibility in sleep initiation. Finally, our data show that this higher nap sleep efficiency is positively related to attentional failures under sleep loss conditions and might thus be used as a marker for inter-individual vulnerability to elevated sleep pressure.

PERIOD3, circadian phenotypes, and sleep homeostasis

Circadian rhythmicity and sleep homeostasis contribute to sleep phenotypes and sleep-wake disorders, some of the genetic determinants of which are emerging. Approximately 10% of the population are homozygous for the 5-repeat allele (PER3(5/5)) of a variable number tandem repeat polymorphism in the clock gene PERIOD3 (PER3). We review recent data on the effects of this polymorphism on sleep-wake regulation. PER3(5/5) are more likely to show morning preference, whereas homozygosity for the four-repeat allele (PER3(4/4)) associates with evening preferences. The association between sleep timing and the circadian rhythms of melatonin and PER3 RNA in leukocytes is stronger in PER3(5/5) than in PER3(4/4). EEG alpha activity in REM sleep, theta/alpha activity during wakefulness and slow wave activity in NREM sleep are elevated in PER3(5/5). PER3(5/5) show a greater cognitive decline, and a greater reduction in fMRI-assessed brain responses to an executive task, in response to total sleep deprivation. These effects are most pronounced during the late circadian night/early morning hours, i.e., approximately 0-4h after the crest of the melatonin rhythm. We interpret the effects of the PER3 polymorphism within the context of a conceptual model in which higher homeostatic sleep pressure in PER3(5/5) through feedback onto the circadian pacemaker modulates the amplitude of diurnal variation in performance. These findings highlight the interrelatedness of circadian rhythmicity and sleep homeostasis.

What keeps us awake? The role of clocks and hourglasses, light, and melatonin

What is it that keeps us awake? Our assumption is that we consciously control our daily activities including sleep-wake behavior, as indicated by our need to make use of an alarm clock to wake up in the morning in order to be at work on time. However, when we travel across multiple time zones or do shift work, we realize that our intentionally planned timings to rest and to remain active can interfere with an intrinsic regulation of sleep/wake cycles. This regulation is driven by a small region in the anterior hypothalamus of the brain, termed as the "circadian clock". This clock spontaneously synchronizes with the environmental light-dark cycle, thus enabling all organisms to adapt to and anticipate environmental changes. As a result, the circadian clock actively gates sleep and wakefulness to occur in synchrony with the light-dark cycles. Indeed, our internal clock is our best morning alarm clock, since it shuts off melatonin production and boosts cortisol secretion and heart rate 2-3h prior awakening from Morpheus arms. The main reason most of us still use artificial alarm clocks is that we habitually carry on a sleep depth and/or the sleep-wake timing is not ideally matched with our social/work schedule. This in turn can lead hourglass processes, as indexed by accumulated homeostatic sleep need over time, to strongly oppose the clock. To add to the complexity of our sleep and wakefulness behavior, light levels as well as exogenous melatonin can impinge on the clock, by means of their so-called zeitgeber (synchronizer) role or by acutely promoting sleep or wakefulness. Here we attempt to bring a holistic view on how light, melatonin, and the brain circuitry underlying circadian and homeostatic processes can modulate sleep and in particular alertness, by actively promoting awakening/arousal and sleep at certain times during the 24-h day.