Sleep function: Toward elucidating an enigma

Slumber under pressure: REM sleep and stress response

Sleep, a state of reduced responsiveness and distinct brain activity, is crucial across the animal kingdom. This review explores the potential adaptive functions of REM sleep in adapting to stress, emphasizing its role in memory consolidation, emotional regulation, and threat processing. We further explore the underlying neural mechanisms linking stress responses to REM sleep. By synthesizing current findings, we propose that REM sleep allows animals to "rehearse" or simulate responses to danger in a secure, offline state, while also maintaining emotional balance. Environmental factors, such as predation risk and social dynamics, further influence REM sleep. This modulation may enhance survival by optimizing stress responses while fulfilling physiological needs in animals. Insights into REM sleep's role in animals may shed light on human sleep in the context of modern stressors and sleep disruptions. This review also explores the complex interplay between stress, immunity, sleep disruptions-particularly involving REM sleep-and their evolutionary underpinnings.

Does vestibular stimulation modify circadian rhythms and sleep? A systematic review

INTRODUCTION

Circadian rhythms and sleep processes are essential in human and their disruption affect health in many ways. They share anatomical-functional pathways with the vestibular system making vestibular stimulation an interesting tool that has yet to prove its efficacy at reducing such disruptions. This review aims at evaluating the effects of different types of vestibular stimulations on circadian rhythms and sleep.

METHODS

It followed PRISMA recommendations and was registered to PROSPERO (CRD42024492913). The databases PubMed and ScienceDirect were searched until January 2024 for articles published between 1950 and 2023 to collect articles fitting the scope of the review.

RESULTS

Among the ninety-six screened studies, a total of twelve studies were included. A significant beneficial effect of vestibular stimulation was shown on a circadian rhythm and in eight out of eleven studies evaluating sleep. Among the twelve studies, three showed a high risk of bias, two induced some concerns and the seven left showed a low risk of bias.

CONCLUSION

Vestibular stimulation appears as a promising technique to improve both circadian rhythms and sleep.

The role of sleep traits in prostate, endometrial, and epithelial ovarian cancers: An observational and Mendelian randomisation study

Background

Sleep traits may influence cancer risk; however, their associations with prostate (PCa), endometrial (ECa), and epithelial ovarian (EOCa) cancer remain unclear.

Methods

We conducted an observational analysis using the UK Biobank cohort and a two-sample Mendelian randomisation (MR) analysis to investigate the association of six sleep traits-duration, chronotype, insomnia, daytime napping, daytime sleepiness, and snoring-with PCa, ECa, and EOCa risk. Cox proportional hazards models were used for the observational analysis, while the inverse variance-weighted (IVW) method was applied in MR, with multiple sensitivity analyses. A Bonferroni correction accounted for multiple testing.

Results

Among 8,608 PCa, 1,079 ECa, and 680 EOCa incident diagnoses (median follow-up: 6.9 years), snoring was associated with reduced EOCa risk (HR=0.78, 95%CI: 0.62-0.98), while daytime sleepiness was associated with increased EOCa risk (HR=1.23, 95%CI: 1.03-1.47). However, these associations were not confirmed in MR. MR suggested higher odds of PCa (OR IVW =1.05, 95%CI: 1.01-1.11) and aggressive PCa (OR IVW =1.10, 95%CI: 1.02-1.19) for evening compared to morning chronotype. None of the findings survived multiple testing correction.

Conclusion

Sleep traits were not associated with PCa, ECa, or EOCa risk, but evening chronotype may increase PCa risk. Further research is needed to verify this association and investigate potential underlying mechanisms.

Impact

The proposed results have potential utility in reproductive cancer prevention.

What is already known on this topic

Sleep traits have been implicated in cancer risk, but their associations with prostate, endometrial, and epithelial ovarian cancer remain unclear.

What this study adds

This study found suggestive evidence that an evening chronotype may be associated with an increased risk of overall and aggressive prostate cancer.

How this study might affect research practice or policy

Further research is needed to confirm the potential association between chronotype and prostate cancer risk, which could inform personalised cancer prevention strategies.

Diet, Eating Habits, and Lifestyle Factors Associated with Adequate Sleep Duration in Children and Adolescents Living in 5 Mediterranean Countries: The DELICIOUS Project

Background/Objectives: Sleep is a fundamental physiological function that plays a crucial role in maintaining health and well-being. The aim of this study was to assess dietary and lifestyle factors associated with adequate sleep duration in children and adolescents living in five Mediterranean countries. Methods: Parents of children and adolescents taking part in an initial survey for the DELICIOUS project were examined to assess their children's dietary and eating habits (i.e., meal routines), as well as other lifestyle behaviors (i.e., physical activity levels, screen time, etc.) potentially associated with adequate sleep duration (defined as 8-10 h according to the National Sleep Foundation). The youth healthy eating index (Y-HEI) was used to assess the diet quality of children and adolescents. Multivariate logistic regression analyses were performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs), indicating the level of association between variables. Results: A total of 2011 individuals participated in the survey. The adolescents and children of younger parents reported being more likely to have inadequate sleep duration. Among eating behaviors, having breakfast (OR = 2.23, 95% CI: 1.62, 3.08) and eating at school (OR = 1.33, 95% CI: 1.01, 1.74) were associated with adequate sleep duration. In contrast, children eating alone, screen time, and eating outside of the home were less likely to have adequate sleep duration, although these findings were only significant in the unadjusted model. After adjusting for covariates, a better diet quality (OR = 1.63, 95% CI: 1.24, 2.16), including higher intake of fruits, meat, fish, and whole grains, was associated with adequate sleep duration. Conclusions: Adequate sleep duration seems to be highly influenced by factors related to individual lifestyles, family and school eating behaviors, as well as diet quality.

Association between sleep timing shifts and dietary quality in Korean high school girls during COVID-19: a cross-sectional study

BACKGROUND/OBJECTIVES

Owing to coronavirus disease 2019 (COVID-19), the shift from offline to online classes has caused significant changes in high school students' daily habits, including sleep patterns and dietary intake. This study explored the association between sleep schedule fluctuations and dietary quality among high school girls during the COVID-19 pandemic. This study examined the association between bedtime, wake-up time, and adolescent dietary quality during the weekly online/offline school period among 517 high school girls in Incheon, South Korea.

SUBJECTS/METHODS

The participants were divided into 2 groups: normal sleepers (n = 244), who maintained normal sleep schedules defined as a midpoint between bedtime and wake-up time before 5:30 a.m., during in-person and online classes; and late sleepers (n = 273), who maintained a normal sleep schedule during in-person classes but exhibited late sleep patterns defined as a midpoint after 5:30 a.m., during online classes.

RESULTS

Shorter sleep duration was characteristic of late sleepers with circadian rhythm disruption, who also displayed poorer dietary quality, including higher consumption of caffeinated beverages and street food and never consuming breakfast. Among the 5 constituent factors, disrupted sleep timing was associated with lower Nutrition Quotient for Adolescents scores in total, moderation, and environment. This association persisted independent of the grade level, even after adjusting for school grade. These findings highlight the significant effect of sleep patterns on dietary habits.

CONCLUSION

This study highlights the significant relationship between disrupted circadian rhythms and poor dietary quality among high-school girls. These findings reveal the need for interventions to promote healthy sleep patterns as a strategy to improve the dietary quality and overall health of adolescents.

Myelin: A possible proton capacitor for energy storage during sleep and energy supply during wakefulness

There are several physiological reasons why biological organisms sleep. One key one concerns brain metabolism. In our article we discuss the role of metabolism in myelin, based on the recent discovery that myelin contains mitochondrial components that enable the production of adenosine triphosphate (ATP) via oxidative phosphorylation (OXPHOS). These mitochondrial components in myelin probably originate from vesiculation of the mitochondrial membranes in form from mitochondrial derived vesicles (MDVs). We hypothesize that myelin acts as a proton capacitor, accumulating energy in the form of protons during sleep and converting it to ATP via OXPHOS during wakefulness. Empirical evidence supporting our hypothesis is discussed, including data on myelin metabolic activity, MDVs, and allometric scaling between white matter volume and sleep duration in mammals.

The night's watch: Exploring how sleep protects against neurodegeneration

Sleep loss is often regarded as an early manifestation of neurodegenerative diseases given its common occurrence and link to cognitive dysfunction. However, the precise mechanisms by which sleep disturbances contribute to neurodegeneration are not fully understood, nor is it clear why some individuals are more susceptible to these effects than others. This review addresses critical unanswered questions in the field, including whether sleep disturbances precede or result from neurodegenerative diseases, the functional significance of sleep changes during the preclinical disease phase, and the potential role of sleep homeostasis as an adaptive mechanism enhancing resilience against cognitive decline and neurodegeneration.

Evaluating sleep's role in type 2 diabetes mellitus: Evidence from NHANES

Background

Evidence is limited regarding the relationship between sleep factors (self-reported sleep disorder diagnosis, subjective sleep difficulties, and sleep duration), sleep patterns, and risk of type 2 diabetes mellitus (T2D). Thus, this study aims to investigate the relationship between sleep factors, sleep patterns, and the risk of T2D using data from the National Health and Nutrition Examination Survey (NHANES).

Methods

A total of 14,652 individuals aged ≥18 years from the NHANES (2005-2014) were enrolled with complete data on sleep factors, T2D, and covariates. Information on self-reported sleep disorder diagnosis, subjective sleep difficulties, and sleep duration was collected during in-home visits by trained interviewers using the Computer-Assisted Personal Interviewing system. The sleep pattern was derived from scoring three mentioned factors: no self-reported sleep disorder diagnosis, no subjective sleep difficulties, and sleep duration of 7-9 h were classified as low-risk (score 0), while the presence of self-reported sleep disorder diagnosis, subjective sleep difficulties, or sleep duration <7 or >9 h were classified as high-risk (score 1). Cumulative scores range from 0 to 3, with 0 indicating a healthy sleep pattern, 1 an intermediate sleep pattern, and 2-3 a poor sleep pattern, respectively. Weighted logistic regression was conducted to assess the association of sleep factors and sleep patterns with the risk of T2D.

Results

Self-reported sleep disorder diagnosis (odds ratio (OR) = 1.32, P = 0.01), subjective sleep difficulties (OR = 1.29, P = 0.001), and sleep deprivation (<7 h; OR = 1.20, P = 0.01) were significantly positive with T2D. Poor sleep pattern also significantly increased T2D risk (OR = 1.52, P < 0.0001). Moreover, subgroup analyses stratified by age and BMI (body mass index) further confirmed that the positive association between sleep patterns and T2D was consistent and robust across groups.

Conclusion

Our findings indicate that poorer sleep patterns are associated with an increased risk of T2D. These results emphasize the importance of sleep management in T2D prevention. Further prospective studies are needed to investigate the causal or bidirectional relationship between sleep and T2D risk, as well as the underlying molecular mechanisms.

Quadratic associations between sleep and multimorbidity among the older population in China: Evidence from CLHLS 2011 to 2018

OBJECTIVES

To investigate the relationship between sleep and multimorbidity, including the associations between sleep duration and multimorbidity, as well as between sleep quality and multimorbidity.

METHODS

Using data from the three latest waves of the Chinese Longitudinal Health Longevity Study (2011, 2014, and 2018), a binary panel regression was conducted to investigate the quadratic relationship between sleep duration and multimorbidity. Subsequently, quadratic fitting and robustness analysis were further utilized to strengthen the verification of this relationship.

RESULTS

From 2011 to 2018, the prevalence of multimorbidity increased, with average rates of 0.309, 0.345, and 0.367, respectively. Meanwhile, sleep duration was 7.45, 7.34, and 7.39, but sleep quality showed a declining trend with scores of 3.70, 3.63, and 3.47, respectively. Furthermore, the regression analysis revealed that the odds ratios (OR) for the relationship between sleep duration and multimorbidity, and between the square of sleep duration and multimorbidity were 0.734, with 95 % CI = [0.6272, 0.8582] and 1.016, with 95 % CI = [1.0058, 1.0262], respectively. From the quadratic relationship, it is evident that the multimorbidity among older Chinese adults initially decreases and then increases with long sleep durations.

CONCLUSIONS

The multimorbidity was significantly different among individuals with different sleep duration. A U-shaped relationship was observed between sleep duration and multimorbidity, whereby both short and excessive sleep durations were associated with higher rates of multimorbidity. Additionally, a negative association was found between sleep quality and multimorbidity, indicating that higher sleep quality was linked to lower rates of multimorbidity.

Are ICU Bedspaces Based in Evidence, and Do They Support Patient Sleep? A Narrative Review

Objective: This narrative review summarizes some of the evidence guiding current intensive care unit (ICU) design, focussing on environmental factors impacting on sleep, and compares available evidence and recommendations to current ICU designs and builds. Background: The importance of sleep for recovery after illness is well known. However, hospitalized patients frequently experience poor and disrupted sleep. This is especially true for patients admitted to the ICU. There are many factors negatively impacting on ICU patients' ability to sleep. Some relate to their illness or pre-existing sleep problems; others relate to patient care activities. While the ICU bedspace may facilitate 24h care, there is growing awareness of the detrimental impact the bedspace environment (especially suboptimal lighting and excessive sound/noise) has on sleep quality, and important questions raised regarding how this may impact on recovery and health outcomes. Multiple guidelines and recommendations exist to guide ICU bedspace design. However, questions have been raised whether contemporary ICUs are evidence-based, and whether the available evidence is effectively translated into the built ICU. Methods: A comprehensive literature review was conducted, exploring the evidence supporting current ICU bedspace design and the impact of ICU design and environmental factors on patient sleep. Results and conclusion: This review summarizes the impact of the ICU bedspace environment on patient outcomes and describes features of the ICU bedspace design that may not adhere to best evidence and contribute to poor sleep. Suggestions on how ICU bedspaces can be improved to optimize sleep are provided.

Association between migraine severity and sleep quality: a nationwide cross-sectional study

Background

Migraine is a primary headache disorder that affects more than 1 billion individuals globally and imposes a significant disability burden on society. Although migraine patients commonly experience poor sleep quality, the relationship between migraine and sleep is not yet fully understood. This study therefore aimed to determine the association between sleep quality and migraine severity.

Methods

A comparative cross-sectional study was conducted with 1,399 participants across all regions of Saudi Arabia from August to October 2023 using standardized questionnaires. Participants were categorized into patients with migraine and non-migraine patients, according to the International Headache Society (IHS) criteria. This study utilized The Migraine Disability Assessment Scale (MIDAS) and Pittsburgh Sleep Quality Index (PSQI) to evaluate migraine severity and sleep quality, respectively.

Results

The prevalence of migraine was 25%, while poor sleep quality was evident in 42.4% of the patients. No significant difference in PSQI scores was observed between patients with migraine and non-migraine patients (p = 0.821). Migraine patients with poor sleep quality showed significantly higher MIDAS scores than those with good sleep quality (10.37 vs. 6.58; p = 0.002), while patients with migraine with higher levels of disability had higher PSQI scores than those with lower levels of disability, although the difference was not statistically significance (7.61 vs. 6.81, p = 0.053). A significant positive correlation was found between the PSQI and MIDAS scores (r = 0.179, p < 0.001). MIDAS was also significantly positively correlated with the following PSQI components: subjective sleep quality (p = 0.047), sleep latency (p < 0.001), sleep disturbance (p < 0.001), and daytime dysfunction (p < 0.001).

Conclusion

These findings suggest a notable correlation between poor sleep quality and increased migraine severity, emphasizing the importance of addressing sleep disturbance as a potential strategy to mitigate migraine severity and improve patient outcomes.

Identification and validation of diagnostic genes IFI44 and IRF9 in insomnia-associated autoimmune uveitis

Objective

Insomnia is increasingly recognized as a significant factor in the development of various autoimmune diseases, including autoimmune uveitis (AU). We investigated insomnia-associated genes that may contribute to AU pathogenesis and sought to identify potential biomarkers for insomnia-associated AU.

Methods

Microarray data related to insomnia and AU were downloaded from the Gene Expression Omnibus (GEO) database and analyzed. The GEO2R tool was used to identify differentially expressed genes (DEGs) that were common between insomnia and AU. Weighted gene co-expression network analysis (WGCNA), protein-protein interaction (PPI), functional enrichment, and CMap analyses were then performed to identify pathogenic genes, underlying mechanisms, and potential therapeutic drugs for insomnia-associated AU. Least absolute shrinkage and selection operator regression was employed to screen for candidate biomarkers, and their diagnostic performance was evaluated using receiver operating characteristic (ROC) curves and quantitative polymerase chain reaction (qPCR). Finally, molecular docking was applied to verify binding activities.

Results

We identified 138 up-regulated and 85 down-regulated DEGs that were common to insomnia and AU. PPI network analysis highlighted 10 key genes, CMap analysis identified 30 compounds, and WGCNA revealed 54 key genes and 30 compounds. Intersection of the above-mentioned key genes and compounds identified six genes and five compounds. After verification by qPCR and ROC curve analysis, IFI44 and IRF9 were confirmed as hub genes. Finally, two compounds were selected based on docking scores of less than -7 kcal/mol.

Conclusion

Our study demonstrated involvement of the viral response in both insomnia and AU and identified the diagnostic significance of IFI44 and IRF9 in these conditions. These findings provide novel insights for future diagnostic and therapeutic strategies to treat insomnia-associated AU.

Physical activity and happiness of college students: chain mediating role of exercise attitude and sleep quality

Introduction

This study explores the role of physical activity, exercise attitude, and sleep quality in college students' happiness, aiming to provide a theoretical basis for improving college students' mental health.

Methods

The study employed a whole group sampling method, utilizing a physical activity level scale, exercise attitude scale, sleep quality scale, and happiness scale. A questionnaire survey was conducted with 1,308 college students from four universities in China.

Results

The analysis yielded three key findings: (1) Physical activity significantly improves college students' happiness, and this improvement can be achieved through direct and indirect effects. (2) Positive exercise attitude plays an important mediating role between physical activity and happiness, and a high level of exercise attitude can enhance happiness. In addition, the effect of physical activity on happiness is most significant through exercise attitude. (3) Although sleep quality did not significantly mediate the relationship between physical activity and happiness alone, it played a positive role in the chain mediation path of "physical activity → exercise attitude → sleep quality → happiness."

Discussion

The discovery of the chain mediation path shows that physical activity not only affects happiness, but also indirectly affects college students' happiness through the combined effects of psychological and physiological factors.

Sleep-wake patterns of fencing athletes: a long-term wearable device study

Objective

Sleep is the most efficient means of recovery for athletes, guaranteeing optimal athletic performance. However, many athletes frequently experience sleep problems. Our study aims to describe the sleep-wake patterns of fencing athletes and determine whether factors, such as sex, competitive level and training schedules, could affect the sleep-wake rhythm.

Methods

Sleep data from 23 fencing athletes were collected using the Huawei Band 6, monitoring key sleep parameters such as bedtime, wake time, duration of deep and light sleep, wake periods, REM sleep duration, and nap duration. During this period, athletes were required to wear the band continuously for 24 hours daily, except bathing, charging, and competition times.

Results

Athletes averaged 7.97 hours of sleep per night, with significant differences observed in wake time (p = 0.015) and midpoint of sleep (p = 0.048) between high-level and low-level athletes, as well as a higher frequency of naps among high-level (χ2 = 11.97, p = 0.001) and female (χ2 = 3.88, p = 0.049) athletes. Nap duration was negatively correlated with night sleep duration (r =  - 0.270, p < 0.001). Athletes were observed for changes in sleep-wake patterns from Monday to Sunday. On Mondays, Wednesdays, and Fridays, when there was no morning training, the athletes' wake-up time and the midpoint of sleep were shifted significantly backward, and there were significant differences in sleep parameters between training days and rest days.

Conclusion

The sleep patterns of athletes differ according to level and gender. The sleep-wake patterns of athletes are influenced by training schedules, indicating the presence of sleep rhythm disruption.

Association between weight-adjusted waist index and obstructive sleep apnea among adults in the United States: data from NHANES (2005-2008 and 2015-2018)

OBJECTIVE

We aimed to examine the relationship between the weight-adjusted waist index (WWI) and obstructive sleep apnea (OSA), a condition often caused by obesity, which remains unclear.

METHODS

In this cross-sectional study, we analyzed data from the National Health and Nutrition Examination Survey among adults in the United States (US) aged 20 to 65 years, covering the periods 2005 to 2008 and 2015 to 2018. The study included 8278 participants; we used multivariate logistic regression, restricted cubic splines, and subgroup analyses to explore the relationship between WWI and OSA.

RESULTS

After adjusting for all covariates, each unit increase in WWI was associated with a 30% increase in OSA prevalence (odds ratio = 1.30, 95% confidence interval: 1.20-1.40).

CONCLUSIONS

These findings suggest that WWI, an index reflecting abdominal obesity, can provide important insights into OSA risk assessment. Its strong association with OSA highlights its potential utility in predicting OSA prevalence, particularly among diverse subpopulations. The WWI was associated with a higher prevalence of OSA among US adults and may serve as a valuable tool for risk assessment, early screening, and intervention strategies in clinical practice.

Dose-response relationship between leisure-time physical activity and metabolic syndrome in short sleep US adults: evidence from a nationwide investigation

Metabolic syndrome (MetS) and short sleep are prevalent health concerns in the United States, yet the relationship between leisure-time physical activity (LTPA) and MetS among individuals with short sleep duration remains unclear. This cross-sectional study analyzed data from 8999 US adults aged 20 years and older in the National Health and Nutrition Examination Survey. Short sleep duration was defined as less than 7 h per night, and MetS was diagnosed based on criteria from the American Endocrine Society and the American Society of Clinical Endocrinology. Weighted regression analyses revealed a significant inverse association between LTPA and MetS, with higher LTPA levels linked to lower MetS (OR (95% CI): 0.990 (0.984, 0.997), p = 0.003). Participants who achieved the World Health Organization's recommended LTPA levels had a substantially lower MetS compared to those with no LTPA (OR (95% CI): 0.624 (0.527, 0.738), p = 0.001). Stratified analyses showed that this protective effect varied across demographic subgroups, and a threshold effect was observed at 2000 MET-min/week, beyond which further LTPA did not significantly enhance protection against MetS. These findings highlight the importance of regular LTPA that is negatively associated with MetS among individuals with inadequate sleep, emphasizing the need for targeted health promotion efforts in this population.

Sleep loss-induced oncogenic pathways are mediated via the neuron-specific interleukin-1 receptor accessory protein (AcPb)

Interleukin-1β (IL1), a pleiotropic cytokine, is involved in sleep regulation, tumor ontogeny, and immune responses. IL1 receptor adaptor proteins, including the IL1 receptor accessory protein (AcP), and its neuron-specific isoform, AcPb, are required for IL1 signaling. The AcPb isoform is resultant from alternate splicing of the AcP transcript. Our previous studies using AcPb null (AcPb-/-) mice characterized its participation in sleep regulation and emergent neuronal/glial network properties. Here, we investigated the impact of acute sleep disruption (SD) on brain cancer-related pathways in wild-type (WT) and AcPb-/- mice, employing RNA sequencing methods. In WT mice, SD increased AcPb mRNA levels, but not AcP mRNA, confirming prior similar work in rats. Transcriptome and pathway enrichment analyses demonstrated significant alterations in cancer, immune, and viral disease-related pathways in WT mice after SD, which were attenuated in AcPb-/- mice including multiple upregulated Src phosphorylation-signaling-dependent genes associated with cancer progression and metastasis. Our RNAseq findings, were analyzed within the context of The Cancer Genome Atlas Program (TCGA) data base; revealing an upregulation of sleep- and cancer-linked genes (e.g., IL-17B, IL-17RA, LCN2) across various tumors, including brain tumors, compared to normal tissues. Sleep-linked factors, identified through TCGA analyses, significantly impact patient prognosis and survival, particularly in low-grade glioma (LGG) and glioblastoma multiforme (GBM) patients. Overall, our findings suggest that SD promotes a pro-tumor environment through AcPb-modulated pathways.

Relationships between orofacial pain and sleep: Analysis of UK biobank and genome-wide association studies data

Background/purpose

Orofacial pain is common in dental practices. This study aimed to explore relationships between orofacial pain and sleep using the UK Biobank dataset and, based on epidemiological associations, to investigate the causal association using genome-wide association studies data.

Materials and methods

First, a cross-sectional study was conducted with 196,490 participants from UK Biobank. Information on pain conditions and sleep traits was collected. Multivariable models were used to explore the relationships with odds ratio (OR). Second, Mendelian randomization analyses were conducted using data for orofacial pain, including temporomandibular joint disorders-related pain (n = 377,277) and atypical facial pain (n = 331,749), and sleep traits, including sleep duration (n = 446,118), short sleep (n = 411,934), long sleep (n = 339,926), snoring (n = 359,916), ease of getting up (n = 385,949), insomnia (n = 453,379), daytime dozing (n = 452,071), daytime napping (n = 452,633), and chronotype (n = 403,195).

Results

The cross-sectional study confirmed the bidirectionality between pain and sleep. Participants experiencing pain all over the body showed a significant association with an unhealthy sleep pattern (OR = 1.18, P < 0.001) and other sleep traits (P < 0.05). Risks of chronic orofacial pain were associated with sleep duration in a non-linear relationship (P = 0.032). The Mendelian randomization analyses indicated that long sleep was causally associated with temporomandibular joint disorders-related pain (OR = 6.77, P = 0.006).

Conclusion

The relationship between pain and sleep is bidirectional. Long sleep is found to be causally associated with chronic orofacial pain.

Sleep induced by mechanosensory stimulation provides cognitive and health benefits in Drosophila

STUDY OBJECTIVES

Sleep is a complex phenomenon regulated by various factors, including sensory input. Anecdotal observations have suggested that gentle rocking helps babies fall asleep, and experimental studies have verified that rocking promotes sleep in both humans and mice. Recent studies have expanded this understanding, demonstrating that gentle vibration also induces sleep in Drosophila. Natural sleep serves multiple functions, including learning and memory, synaptic downscaling, and reduction of harmful substances associated with neurodegenerative diseases. Here, we investigated whether vibration-induced sleep (VIS) provides similar cognitive and health benefits in Drosophila.

METHODS

We administered gentle vibration to flies that slept very little due to a forced activation of wake-promoting neurons and investigated how the vibration influenced learning and memory in the courtship conditioning paradigm. Additionally, we examined the effects of VIS on synaptic downscaling by counting synaptic varicosities of select neurons. Finally, we determined whether vibration could induce sleep in Drosophila models of Alzheimer's disease (AD) and suppress the accumulation of Amyloid β (Aβ) and Tubulin Associated Unit (TAU).

RESULTS

VIS enhanced performance in a courtship conditioning paradigm and reduced the number of synaptic varicosities in select neurons. Moreover, vibration improved sleep in Drosophila models of AD, reducing Aβ and TAU levels.

CONCLUSIONS

Mechanosensory stimulation offers a promising noninvasive avenue for enhancing sleep, potentially providing associated cognitive and health benefits.

The effect of group size on sleep in a neotropical bat, Artibeus jamaicensis

Sleep is associated with many costs, but is also important to survival, with a lack of sleep impairing cognitive function and increasing mortality. Sleeping in groups could alleviate sleep-associated costs, or could introduce new costs if social sleeping disrupts sleep. Working with the Jamaican fruit bat (Artibeus jamaicensis), we aimed to: (1) describe sleep architecture, (2) assess how sleeping in groups affects sleep, and (3) quantify total sleep time and identify rapid eye movement (REM) sleep using behavioral indicators that complement physiological evidence of sleep. Twenty-five adult bats were captured in Panama and recorded sleeping in an artificial roost enclosure. Three bats were fitted with an electromyograph and accelerometer and video recorded sleeping alone in controlled laboratory settings. The remaining 22 bats were assigned to differing social configurations (alone, dyad, triad, and tetrad) and video recorded sleeping in an outdoor flight cage. We found that sleep was highly variable among individuals (ranging from 2 h 53 min to 9 h 39 min over a 12-h period). Although we did not detect statistically significant effects and our sample size was limited, preliminary trends suggest that male bats may sleep longer than females, and individuals sleeping in groups may sleep longer than individuals sleeping alone. We also found a high correspondence between total sleep time quantified visually and quantified using actigraphy (with a 2-min immobility threshold) and identified physiological correlates of behaviorally-defined REM. These results serve as a starting point for future work on the ecology and evolution of sleep in bats and other wild mammals.

Alterations in Circadian Rhythms, Sleep, and Physical Activity in COVID-19: Mechanisms, Interventions, and Lessons for the Future

Although the world is acquitting from the throes of COVID-19 and returning to the regularity of life, its effects on physical and mental health are prominently evident in the post-pandemic era. The pandemic subjected us to inadequate sleep and physical activities, stress, irregular eating patterns, and work hours beyond the regular rest-activity cycle. Thus, perturbing the synchrony of the regular circadian clock functions led to chronic psychiatric and neurological disorders and poor immunological response in several COVID-19 survivors. Understanding the links between the host immune system and viral replication machinery from a clock-infection biology perspective promises novel avenues of intervention. Behavioral improvements in our daily lifestyle can reduce the severity and expedite the convalescent stage of COVID-19 by maintaining consistent eating, sleep, and physical activity schedules. Including dietary supplements and nutraceuticals with prophylactic value aids in combating COVID-19, as their deficiency can lead to a higher risk of infection, vulnerability, and severity of COVID-19. Thus, besides developing therapeutic measures, perpetual healthy practices could also contribute to combating the upcoming pandemics. This review highlights the impact of the COVID-19 pandemic on biological rhythms, sleep-wake cycles, physical activities, and eating patterns and how those disruptions possibly contribute to the response, severity, and outcome of SARS-CoV-2 infection.

Sleep and diurnal alternative polyadenylation sites associated with human APA-linked brain disorders

Disruption of sleep and circadian rhythms are a comorbid feature of many pathologies, and can negatively influence many health conditions, including neurodegenerative disease, metabolic illness, cancer, and various neurological disorders. Genetic association studies linking sleep and circadian disturbances with disease susceptibility have mainly focused on changes in gene expression due to mutations, such as single-nucleotide polymorphisms. The interaction between sleep and/or circadian rhythms with the use of Alternative Polyadenylation (APA) has been largely undescribed, particularly in the context of other disorders. APA generates transcript isoforms by utilizing various polyadenylation sites (PASs) from the same gene affecting its mRNA translation, stability, localization, and subsequent function. Here we identified unique APAs expressed in rat brain over time-of-day, immediately following sleep deprivation, and the subsequent recovery period. From these data, we performed a secondary analysis of these sleep- or time-of-day associated PASs with recently described APA-linked human brain disorder susceptibility genes.

Influence of sedentary behavior and physical activity in leisure and work on sleep duration: data from NHANES 2017-2018

OBJECTIVE

To evaluate the association between sedentary behavior (SB), moderate to vigorous physical activity (MVPA), and sleep duration.

METHODS

Data from the 2017-2018 National Health and Nutrition Examination Survey (NHANES) was analyzed. SB was assessed based on the average daily sitting time, while MVPA was estimated by the frequency and duration of leisure and work-related activities. The ratio of time spent in MVPA to time in SB was analyzed, and a thresholds of ≥ 1.0, 2.5 and 10 min of MVPA per sedentary hour was used to determine sufficiency for mitigating the effects of a sedentary lifestyle. Sleep duration was measured by the average hours slept on weekdays and weekends, classified according to National Sleep Foundation guidelines. The measures of SB, MVPA, and sleep were self-reported. Descriptive statistics were used to characterize the sample, and multivariate logistic regression was applied to assess the associations between movement behaviors and sleep duration.

RESULTS

The study included 5,533 participants, with 51.8% women, predominantly aged 26-64 years (66.1%). Insufficient physical activity was reported by 59.6% at work and 62.5% during leisure time. Recommended sleep duration was observed in 84.4% of the sample. Adjusted multivariate analysis revealed that individuals engaging in ≥ 2.5 min of MVPA during leisure-time for each sedentary hour were 38.9% less likely to experience short-term sleep (OR:0.72;95%CI:0.53-0.97). Conversely, those who performed the same amount of MVPA at work were 57.0% more likely to have short-term sleep (OR:1.57;95%CI:1.16-2.12).

CONCLUSION

Meeting the MVPA threshold during leisure-time reduces the likelihood of short-term sleep, while higher MVPA levels at work increase the likelihood of short-term sleep.

Combined association between dietary antioxidant quality score and leisure-time physical activity on sleep pattern in cancer survivors: a cross-sectional study of National Health and Nutrition Examination Surveys database

This study aimed to explore the combined association between the dietary antioxidant quality score (DAQS) and leisure-time physical activity on sleep patterns in cancer survivors. Data of cancer survivors were extracted from the National Health and Nutrition Examination Surveys database in 2007-2014 in this cross-sectional study. Weighted multivariable logistic regression models were used to estimate OR and 95 % CI for the association of DAQS and leisure-time physical activity on sleep patterns. The combined association was also assessed in subgroups of participants based on age and use of painkillers and antidepressants. Among the eligible participants, 1133 had unhealthy sleep patterns. After adjusting for covariates, compared with low DAQS level combined with leisure-time physical activity level < 600 MET·min/week, high DAQS level combined with leisure-time physical activity ≥ 600 MET·min/week was associated with lower odds of unhealthy sleep patterns (OR = 0·41, 95 % CI: 0·23, 0·72). Additionally, the association of high DAQS level combined with high leisure-time physical activity with low odds of unhealthy sleep patterns was also significant in < 65 years old (OR = 0·30, 95 % CI: 0·13, 0·70), non-painkiller (OR = 0·39, 95 % CI: 0·22, 0·71), non-antidepressant (OR = 0·49, 95 % CI: 0·26, 0·91) and antidepressant (OR = 0·11, 95 % CI: 0·02, 0·50) subgroups. DAQS and leisure-time physical activity had a combined association on sleep patterns in cancer survivors. However, the causal associations of dietary nutrient intake and physical activity with sleep patterns in cancer survivors need further clarification.

Auditory circuits: Watchmen of the sleeping brain

A new study shows that glutamatergic neurons of the pontine central gray (PCG) play a key role in mediating rapid sound-induced awakenings from sleep by relaying short-latency auditory information to multiple arousal centers in the brain.

Tapeworm infection affects sleep-like behavior in three-spined sticklebacks

Sleep is a complex and conserved biological process that affects several body functions and behaviors. Evidence suggests that there is a reciprocal interaction between sleep and immunity. For instance, fragmented sleep can increase the probability of parasitic infections and reduce the ability to fight infections. Moreover, viral and bacterial infections alter the sleep patterns of infected individuals. However, the effects of macro-parasitic infections on sleep remain largely unknown, and measuring sleep in non-model organisms remains challenging. In this study, we investigated whether macro-parasite infections could alter sleep-like behavior of their hosts. We experimentally infected three-spined sticklebacks (Gasterosteus aculeatus), a freshwater fish, with the tapeworm Schistocephalus solidus and used a hidden Markov model to characterize sleep-like behavior in sticklebacks. One to four days after parasite exposure, infected fish showed no difference in sleep-like behavior compared with non-exposed fish, and fish that were exposed-but-not-infected only showed a slight reduction in sleep-like behavior during daytime. Twenty-nine to 32 days after exposure, infected fish showed more sleep-like behavior than control fish, while exposed-but-not-infected fish showed overall less sleep-like behavior. Using brain transcriptomics, we identified immune- and sleep-associated genes that potentially underlie the observed behavioral changes. These results provide insights into the complex association between macro-parasite infection, immunity, and sleep in fish and may thus contribute to a better understanding of reciprocal interactions between sleep and immunity.

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.

Objective sleep enhancement in Parkinson's disease: A sham-controlled trial of low-frequency repetitive transcranial magnetic stimulation over the right dorsolateral prefrontal cortex

INTRODUCTION

Parkinson's disease (PD) is often accompanied by sleep disturbances, impacting patients' quality of life. While repetitive transcranial magnetic stimulation (rTMS) shows promise in improving self-reported sleep quality, its effects on objective sleep architecture in PD remain understudied. Sleep disturbances, including rapid eye movement (REM) and slow-wave sleep disturbances, correlate with cognitive decline and motor symptoms. This study investigated the effect of low-frequency rTMS targeting the right dorsolateral prefrontal cortex (DLPFC) modifying objective sleep architecture and explored symptom improvement mechanisms in PD patients.

METHODS

In this randomized, double-blind, sham-controlled trial, 67 PD patients received 10 consecutive days of 1-Hz rTMS over the right DLPFC. Polysomnography assessed sleep microstructure, while electroencephalogram recordings evaluated power spectral density and sleep spindle activity. Clinical scales measured sleep quality, motor symptoms, and cognition at baseline, post-treatment, and 3 months post-rTMS.

RESULTS

The rTMS group exhibited improvements in sleep quality, motor symptoms, and cognition post-treatment, persisting at the 3-month follow-up. There was a notable increase in the REM sleep proportion post-rTMS. The rTMS group exhibited elevated low-frequency (0.5-2 Hz) slow-wave electroencephalogram spectral density during non-REM sleep. Cognitive enhancement correlated with increased lower delta power, while motor symptom progression correlated with spindle frequency and slow-wave sleep percentage changes.

CONCLUSION

Low-frequency rTMS targeting the right DLPFC holds promise for improving clinical symptoms and modulating sleep architecture in PD. These findings suggest a link between symptom improvement and sleep structure enhancement, highlighting the need for further investigation into the therapeutic potential of rTMS in PD management.

Sleep and diurnal alternative polyadenylation sites associated with human APA-linked brain disorders

Disruption of sleep and circadian rhythms are a comorbid feature of many pathologies, and can negatively influence many health conditions, including neurodegenerative disease, metabolic illness, cancer, and various neurological disorders. Genetic association studies linking sleep and circadian disturbances with disease susceptibility have mainly focused on changes in gene expression due to mutations, such as single-nucleotide polymorphisms. The interaction between sleep and/or circadian rhythms with the use of Alternative Polyadenylation (APA) has been largely undescribed, particularly in the context of other disorders. APA is a process that generates various transcript isoforms of the same gene affecting its mRNA translation, stability, localization, and subsequent function. Here we identified unique APAs expressed in rat brain over time-of-day, immediately following sleep deprivation, and the subsequent recovery period. From these data, we performed a secondary analysis of these sleep- or time-of-day associated PASs with recently described APA-linked human brain disorder susceptibility genes.

The abnormalities of brain function in females with primary insomnia: a resting-state functional magnetic resonance imaging study

Background

The neuropathologic mechanism of primary insomnia (PI) of females remains unclear. This study aims to investigate the features of amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) in females with PI using functional magnetic resonance imaging (fMRI), and then explore the abnormalities of functional connectivity (FC).

Materials and methods

A total of 39 female PI patients and 31 female healthy controls (HC) were enrolled in the study. The sleep condition was assessed using the Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI), and their depressive symptom was evaluated using the Hamilton Depression Scale (HAMD-24). The rs-fMRI was once conducted for every subject. ReHo, ALFF, and ROI-based FC were used to analyze the changes of brain function.

Results

ALFF values were increased in the Cerebelum_4_5_L, as well as decreased ALFF in the bilateral Frontal_Sup_Medial (SFGmed), Angular_L (ANG.L), Parietal_Inf_R (IPL.R), SupraMarginal_R (SMG.R), and Postcentral_R (PoCG.R). ReHo values were increased in the Temporal_Pole_Mid_R (TPOsup.R), as well as decreased ReHo in the Insula_R (INS.R), Frontal_Inf_Oper_R (ORBinf.R), Putamen_R (PUT.R), Rolandic_Oper_R (ROL.R), bilateral Cingulum_Post (PCG), bilateral Frontal_Sup_Medial (SFGmed), bilateral anterior cingulate and paracingulate gyri (ACG), and the bilateral precuneus (PCUN). Across the entire brain, there was a decline in the FC between Angular_R and Frontal_Sup_Medial_L.

Conclusion

Alterations in brain regions of female patients with PI involved multiple functional networks, including the default mode network, the salience network, the central executive network, and the limbic network. Reduced coordination between functional networks may be an important mechanism for insomnia and may lead to reduced cognitive function and decision-making ability.

NLRP3-mediated autophagy dysfunction links gut microbiota dysbiosis to tau pathology in chronic sleep deprivation

Emerging evidence indicates that sleep deprivation (SD) can lead to Alzheimer's disease (AD)-related pathological changes and cognitive decline. However, the underlying mechanisms remain obscure. In the present study, we identified the existence of a microbiota-gut-brain axis in cognitive deficits resulting from chronic SD and revealed a potential pathway by which gut microbiota affects cognitive functioning in chronic SD. Our findings demonstrated that chronic SD in mice not only led to cognitive decline but also induced gut microbiota dysbiosis, elevated NLRP3 inflammasome expression, GSK-3β activation, autophagy dysfunction, and tau hyperphosphorylation in the hippocampus. Colonization with the "SD microbiota" replicated the pathological and behavioral abnormalities observed in chronic sleep-deprived mice. Remarkably, both the deletion of NLRP3 in NLRP3 -/- mice and specific knockdown of NLRP3 in the hippocampus restored autophagic flux, suppressed tau hyperphosphorylation, and ameliorated cognitive deficits induced by chronic SD, while GSK-3β activity was not regulated by the NLRP3 inflammasome in chronic SD. Notably, deletion of NLRP3 reversed NLRP3 inflammasome activation, autophagy deficits, and tau hyperphosphorylation induced by GSK-3β activation in primary hippocampal neurons, suggesting that GSK-3β, as a regulator of NLRP3-mediated autophagy dysfunction, plays a significant role in promoting tau hyperphosphorylation. Thus, gut microbiota dysbiosis was identified as a contributor to chronic SD-induced tau pathology via NLRP3-mediated autophagy dysfunction, ultimately leading to cognitive deficits. Overall, these findings highlight GSK-3β as a regulator of NLRP3-mediated autophagy dysfunction, playing a critical role in promoting tau hyperphosphorylation.

Sleep induced by mechanosensory stimulation provides cognitive and health benefits in Drosophila

Study Objectives

Sleep is a complex phenomenon regulated by various factors, including sensory input. Anecdotal observations have suggested that gentle rocking helps babies fall asleep, and experimental studies have verified that rocking promotes sleep in both humans and mice. Recent studies have expanded this understanding, demonstrating that gentle vibration also induces sleep in Drosophila. Natural sleep serves multiple functions, including learning and memory, synaptic downscaling, and clearance of harmful substances associated with neurodegenerative diseases. Here, we investigated whether vibration-induced sleep provides similar cognitive and health benefits in Drosophila.

Methods

We administered gentle vibration to flies that slept very little due to a forced activation of wake-promoting neurons and investigated how the vibration influenced learning and memory in the courtship conditioning paradigm. Additionally, we examined the effects of VIS on synaptic downscaling by counting synapse numbers of select neurons. Finally, we determined whether vibration could induce sleep in Drosophila models of Alzheimer's disease (AD) and promote the clearance of Amyloid b (Ab) and Tubulin Associated Unit (TAU).

Results

Vibration-induced sleep enhanced performance in a courtship conditioning paradigm and reduced the number of synapses in select neurons. Moreover, vibration improved sleep in Drosophila models of AD, promoting the clearance of Ab and TAU.

Conclusions

Mechanosensory stimulation offers a promising non-invasive avenue for enhancing sleep, potentially providing associated cognitive and health benefits.

Relationship between dietary diversity and sleep quality: a Chinese community-based study

OBJECTIVES

The objective of this study was to examine the association between dietary diversity and sleep quality among Chinese middle-aged and older adults.

METHODS

The Lifestyle and Healthy Aging of Chinese Square Dancer Study is a prospective, community-based cohort study that enrolled participants aged 45 years and above from 2020 to 2021. Using the semiquantitative food frequency questionnaire to investigate the diets of study participants, and using the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. Dietary diversity was assessed using two scoring methods covering ten food groups and 66 food items, respectively: the dietary diversity score (DDS) and the food variety score (FVS). The higher scores of DDS and FVS indicated greater dietary diversity and higher dietary quality. Logistic regression analysis explored the associations between these scores and sleep quality.

RESULTS

A total of 2409 individuals with completed information on PSQI and FFQ were included in this study, of whom 767 (31.8%) had poor sleep quality. Participants with higher DDS were associated with an 18% lower odds of poor sleep quality compared to those with low DDS (OR = 0.82, 95% CI, 0.68-0.98). Participants in the highest quartile of the FVS had a 32% lower odds of poor sleep quality than those in the lowest quartile (OR = 0.68, 95% CI, 0.52-0.89).

CONCLUSIONS

There was a positive correlation between higher FVS and DDS with better sleep quality. Therefore, ensuring a diverse diet may be beneficial for maintaining good sleep quality among middle-aged and older adults.

Genetic evidence for the causal effects of C-reactive protein on self-reported habitual sleep duration

Inflammatory responses to acute stimuli are proposed to regulate sleep, but the relationship between chronic inflammation and habitual sleep duration is elusive. Here, we study this relation using genetically predicted level of chronic inflammation, indexed by CRP and IL6 signaling, and self-reported sleep duration. By Mendelian randomization analysis, we show that elevated CRP level within <10 mg/L has a homeostatic effect that facilitates maintaining 7-8 h sleep duration per day - making short-sleepers sleep longer (p = 2.42 × 10-2) and long-sleepers sleep shorter (1.87 × 10-7); but it is not associated with the overall sleep duration (p = 0.17). This homeostatic effect replicated in an independent CRP dataset. We observed causal effects of the soluble interleukin 6 receptor and gp130 on overall sleep duration (p = 1.62 × 10-8, p = 2.61 × 10-58, respectively), but these effects disappeared when CRP effects were accounted for in the model. Using polygenic score analysis, we found that the homeostatic effect of CRP on sleep duration stems primarily from the genetic variants within the CRP gene region: when genetic variants outside of this region were used to predict CRP levels, the opposite direction of effect was observed. In conclusion, we show that elevated CRP level may causally facilitate maintaining an optimal sleep duration that is beneficial to health, thus updating our current knowledge of immune regulation on sleep.

Sleep Patterns in Patients After Solid Organ Transplantation Including Gender and Age Differences. Survey Results From One Transplantation Centre in Poland

INTRODUCTION

Sleep plays a crucial role in maintaining health. Transplant patients are exposed to numerous stressors and are at risk of sleep disturbances. The aim of this study was to assess the sleep patterns of transplant patients.

METHODS

An anonymous paper survey was carried out among patients from one transplant center in Poland. Respondents were asked about the quality and quantity of sleep and the overall impact of the transplantation on their night rest. Data were collected from June to November 2023.

RESULTS

Data were obtained from 212 respondents (122 males and 90 females), aged 48.38 ± 13.68. The positive impact of transplantation on sleep hygiene was indicated by 57.4% of respondents, 28.9% observed no impact, and 13.6% rated the impact as negative. Our study showed that sleep is more satisfying in males than in females (62.8% of males and 46.7% of females). The analysis revealed that 38.9% of females need 30 minutes more than men to fall asleep. Additionally, females tend to get up half an hour later compared to men. About 71.9% of males declared good well-being the next day compared to 62.2% of females. Furthermore females declared more sleepiness the next day. The study also showed that older transplant recipients (over 50 years-of-age) report more frequent awakenings at night.

CONCLUSIONS

The data collected showed differences in sleep patterns according to gender and age. Females and older patients should be screened for sleep disturbances during post-transplantation care.

Sleep loss impairs blood-brain barrier function: Cellular and molecular mechanisms

Sleep is a physiological process that preserves the integrity of the neuro-immune-endocrine network to maintain homeostasis. Sleep regulates the production and secretion of hormones, neurotransmitters, cytokines and other inflammatory mediators, both at the central nervous system (CNS) and at the periphery. Sleep promotes the removal of potentially toxic metabolites out of the brain through specialized systems such as the glymphatic system, as well as the expression of specific transporters in the blood-brain barrier. The blood-brain barrier maintains CNS homeostasis by selectively transporting metabolic substrates and nutrients into the brain, by regulating the efflux of metabolic waste products, and maintaining bidirectional communication between the periphery and the CNS. All those processes are disrupted during sleep loss. Brain endothelial cells express the blood-brain barrier phenotype, which arises after cell-to-cell interactions with mural cells, like pericytes, and after the release of soluble factors by astroglial endfeet. Astroglia, pericytes and brain endothelial cells respond differently to sleep loss; evidence has shown that sleep loss induces a chronic low-grade inflammatory state at the CNS, which is associated with blood-brain barrier dysfunction. In animal models, blood-brain barrier dysfunction is characterized by increased blood-brain barrier permeability, decreased tight junction protein expression and pericyte detachment from the capillary wall. Blood-brain barrier dysfunction may promote defects in brain clearance of potentially neurotoxic metabolites and byproducts of neural physiology, which may eventually contribute to neurodegenerative diseases. This chapter aims to describe the cellular and molecular mechanisms by which sleep loss modifies the function of the blood-brain barrier.

Effect of a nutraceutical combination on sleep quality among people with impaired sleep: a randomised, placebo-controlled trial

In this randomised, placebo-controlled trial, adults with impaired sleep (Pittsburgh Sleep Quality Index ≥ 5) were randomly assigned using a minimization algorithm to receive a formulation containing L-theanine plus lemon balm, valerian, and saffron extracts, or placebo, during 6 weeks. Objective sleep quality parameters were measured using an actigraphy device. We enrolled and randomised 64 individuals, 31 from the active group and 27 from the placebo group completed the 6 week follow-up. Mean sleep efficiency remained unmodified in the active group, and increased by 3% in the placebo group, the between-group difference in the change was not statistically significant (p = 0.49). Total sleep time also improved more with placebo (13.0 vs. 1.33 min, p = 0.66). Time wake after sleep onset (WASO) decreased more in the active group (4.6% vs. 2.4%), but the difference was not significant (p = 0.33). Mean PSQI decreased by 3.11 points (32.3%) in the active group, and by 3.86 points (39.5%) in the placebo group (p = 0.41). SF-36 increased more with placebo (+ 18.3 in active, + 32.1 in placebo, p = 0.68). Salivary cortisol remained unchanged in both groups. No serious adverse events were reported. Among adults with impaired sleep, a nutraceutical combination did not improve objective or subjective sleep parameters more than a placebo infusion.

Effectiveness of Brain Gym Exercises Over Cognitive Behavioural Therapy in Improving Sleep Quality Among Healthcare University Students: A Comparative Study

Background More than half of healthcare university students are believed to experience inadequate sleep. The application of brain gym exercises is a relatively new concept that has shown potential for addressing a variety of cognitive and perceptual deficits. Nevertheless, its use in managing sleep disorders is still in the early stages. Though cognitive behavioral therapy (CBT) is still the standard treatment for sleep management, recent research suggests that brain gym exercises may help with sleep disorders like insomnia. Independent studies have demonstrated the efficacy of CBT and brain gym activities in treating sleep disorders. Yet, there remains a paucity of studies directly comparing these two methods in treating individuals with sleep disturbances. Aim and objectives To ascertain the effectiveness of brain gym exercises over cognitive behavioral therapy in improving sleep quality among healthcare university students. Method The experimental study comparing brain gym exercises and cognitive behavioral therapy interventions was conducted in Wardha, Maharashtra, India, from March 2023 to December 2023, with 60 subjects selected after considering inclusion and exclusion criteria. The protocol was administered for 4 weeks for 30 minutes per day. The baseline outcome measures were the insomnia severity index (ISI) and the Pittsburgh sleep quality index (PSQI). The outcome measure was used before and after 4 weeks of interventions to evaluate the outcome of the protocol. The software used in the analysis was SPSS 27.0 version and GraphPad Prism 7.0 version, and p<0.05 was considered as the level of significance. Result Post-treatment, evidence was observed for ISI (20.55, P = 0.0001) and PSQI (18.09, P = 0.0001) in Group A. Post-rehabilitation evidence was observed in Group B for ISI (19, P=0.0001) and PSQI (16.64, P=0.0001). The findings revealed a significantly higher mean difference between Group A and Group B, showing a considerable improvement in outcome measure scores within Group A relative to Group B. Conclusion The statistical analysis demonstrates a notable improvement in the pre-and post-scores of the ISI and PSQI following four weeks of brain gym exercises. In comparison, cognitive behavioral therapy showed comparatively less effectiveness in addressing insomnia. The observed improvement in sleep quality among students highlights that brain gym exercises have the potential to be a non-pharmacological alternative for managing mild to moderate insomnia.

Lateralized brunt of sleep deprivation on white matter injury in a rat model of Alzheimer's disease

Sleep disturbance is a recognized risk factor for Alzheimer's disease (AD), but the underlying micro-pathological evidence remains limited. To bridge this gap, we established an amyloid-β oligomers (AβO)-induced rat model of AD and subjected it to intermittent sleep deprivation (SD). Diffusion tensor imaging (DTI) and transmission electron microscopy were employed to assess white matter (WM) integrity and ultrastructural changes in myelin sheaths. Our findings demonstrated that SD exacerbated AβO-induced cognitive decline. Furthermore, we found SD aggravated AβO-induced asymmetrical impairments in WM, presenting with reductions in tract integrity observed in commissural fibers and association fasciculi, particularly the right anterior commissure, right corpus callosum, and left cingulum. Ultrastructural changes in myelin sheaths within the hippocampus and corpus callosum further confirmed a lateralized effect. Moreover, SD worsened AβO-induced lateralized disruption of the brain structural network, with impairments in critical nodes of the left hemisphere strongly correlated with cognitive dysfunction. This work represents the first identification of a lateralized impact of SD on the mesoscopic network and cognitive deficits in an AD rat model. These findings could deepen our understanding of the complex interplay between sleep disturbance and AD pathology, providing valuable insights into the early progression of the disease, as well as the development of neuroimaging biomarkers for screening early AD patients with self-reported sleep disturbances. Enhanced understanding of these mechanisms may pave the way for targeted interventions to alleviate cognitive decline and improve the quality of life for individuals at risk of or affected by AD.

The effect of anxiety on sleep disorders in medical students: a moderated mediation model

The relationship between anxiety and sleep disorders is a key research topic in the academic community. However, evidence on the mechanism through which anxiety influences sleep disorders remains limited. The purpose of this study was to investigate the roles of flourishing and neuroticism in the mechanism through which anxiety influences sleep disorders in medical students. We constructed a moderated mediation model and tested the mediating role of flourishing and the moderating role of neuroticism in medical college students. The results showed that: (1) anxiety was significantly and positively related to sleep disorders and significantly and negatively related to flourishing; flourishing was significantly and negatively related to sleep disorders; neuroticism was significantly and positively related to sleep disorders; (2) flourishing had a mediation effect on the relationship between anxiety and sleep disorders; (3) neuroticism moderated the process through which flourishing mediated the effect of anxiety on sleep disorders. Our research expands the literature on the mechanism underlying the effects of anxiety on sleep disorders and provides insights into the potential prevention and intervention of sleep and emotional problems in medical students.

Examining the prevalence of sleep disturbances in patients seeking physical therapy services

OBJECTIVE

The purpose of this study was to assess the prevalence of sleep disturbances in adults seeking physical therapy services.

METHODS

Participants were issued an electronic survey to provide demographic information and the following questionnaires: Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Sleep Hygiene Index (SHI), Insomnia Severity Index (ISI), STOP-BANG (obstructive sleep apnea (OSA) risk), and restless leg syndrome (RLS) risk. Percentages were calculated to describe prevalence of sleep disturbances, and Spearman's correlations were used to identify associations between pain and sleep questionnaires.

RESULTS

Eighty-eight participants (47.9 ± 15.8 years, 68 females) completed the survey. Seventy-eight percent (n = 69) scored >5 on the PSQI; 32% (n = 28) scored ≥10 on the ESS; 52% (n = 46) scored ≥16 on the SHI; 51% (n = 45) scored ≥10 on the ISI; 28% (n = 25) had intermediate or high risk of OSA; and 40% (n = 35) indicated possible RLS. Pain level was significantly associated with PSQI (r(86) = 0.277, p = .009) and ISI (r(86) = 0.268, p = .012).

CONCLUSIONS

There was a higher prevalence of sleep disturbances in adults seeking physical therapy services than in the general population. Increased pain severity was associated with poorer sleep quality and increased insomnia symptoms. This study highlights the need to screen patients for sleep disturbances.

The glymphatic system and Amyotrophic lateral sclerosis

The glymphatic system and the meningeal lymphatic vessels provide a pathway for transport of solutes and clearance of toxic material from the brain. Of specific relevance to ALS, this is applicable for TDP-43 and glutamate, both major elements in disease pathogenesis. Flow is propelled by arterial pulsation, respiration, posture, as well as the positioning and proportion of aquaporin-4 channels (AQP4). Non-REM slow wave sleep is the is key to glymphatic drainage which discontinues during wakefulness. In Parkinson's disease and Alzheimer's disease, sleep impairment is known to predate the development of characteristic clinical features by several years and is associated with progressive accumulation of toxic proteinaceous products. While sleep issues are well described in ALS, consideration of preclinical sleep impairment or the potential of a failing glymphatic system in ALS has rarely been considered. Here we review how the glymphatic system may impact ALS. Preclinical sleep impairment as an unrecognized major risk factor for ALS is considered, while potential therapeutic options to improve glymphatic flow are explored.

Glymphatic system dysfunction in middle-aged and elderly chronic insomnia patients with cognitive impairment evidenced by diffusion tensor imaging along the perivascular space (DTI-ALPS)

BACKGROUND

Chronic insomnia impairs the glymphatic system and may lead to cognitive impairment and dementia in elderly population. The diffusion tensor image analysis along the perivascular space (DTI-ALPS) has been proposed as a non-invasive method to measure the activity of human brain glymphatic. We aim to explore whether glymphatic function is impaired in middle-aged and elderly chronic insomnia individuals and to identify the relationships between glymphatic dysfunction and cognitive impairment.

METHODS

A total of 33 chronic insomnia patients (57.36 ± 5.44 years, 30 females) and 20 age- and sex-matched healthy controls (57.95 ± 5.78 years, 16 females) were prospectively enrolled between May 2022 and January 2023. All participants completed MRI screening, cognition and sleep assessments, and DTI-ALPS index analysis.

RESULTS

Our findings revealed that the DTI-ALPS index was significantly difference among the chronic insomnia patients with impaired cognition group (1.32 ± 0.14), with normal cognition group (1.46 ± 0.09), and healthy controls (1.61 ± 0.16) (p = 0.0012, p < 0.0001, p = 0.0008, respectively). Mini-Mental State Examination (MMSE) scores of chronic insomnia patients with cognitive impairment were positively correlated with the DTI-ALPS index (Partial correlation analyses after correction for age, sex, education level and duration of chronic insomnia: r = 0.78, p = 0.002). DTI-ALPS had moderate accuracy in distinguishing chronic insomnia patients with cognitive impairment from those with normal cognition.

DATA CONCLUSION

The glymphatic system dysfunction is involved in chronic insomnia among middle-aged and elderly individuals, and it has been found to be correlated with cognitive decline.

Restless nights when sick: ectoparasite infections alter rest-activity cycles of diurnal fish hosts

Circadian rhythms are timekeeping mechanisms responsible for an array of biological processes. Disruption of such cycles can detrimentally affect animal health. Circadian rhythms are critical in the co-evolution of host–parasite systems, as synchronization of parasite rhythms to the host can influence infection dynamics and transmission potential. This study examines the circadian rhythms in behaviour and activity of a model fish species (Poecilia reticulata) in isolation and in shoals, both when uninfected and infected with an ectoparasite (Gyrodactylus turnbulli). Additionally, the rhythmical variance of parasite activity under different light conditions as well as rhythmical variance in parasite transmissibility was explored. Overall, infection alters the circadian rhythm of fish, causing nocturnal restlessness. Increased activity of gyrodactylids on the host's skin at night could potentially contribute to this elevated host activity. Whilst migration of gyrodactylids across the host's skin may have caused irritation to the host resulting in nocturnal restlessness, the disruption in guppy activity rhythm caused by the expression of host innate immunity cannot be excluded. We discuss the wider repercussions such behavioural responses to infection have for host health, the implications for animal behaviour studies of diurnal species as well as the application of chronotherapeutic approaches to aquaculture.

The glymphatic system and multiple sclerosis: An evolving connection

Multiple sclerosis (MS) is a complex autoimmune disorder that affects the central nervous system, resulting in demyelination and an array of neurological manifestations. Recently, there has been significant scientific interest in the glymphatic system, which operates as a waste-clearance system for the brain. This article reviews the existing literature, and explores potential links between the glymphatic system and MS, shedding light on its evolving significance in the context of MS pathogenesis. The authors consider the pathophysiological implications of glymphatic dysfunction in MS, the impact of disrupted sleep on glymphatic function, and the bidirectional relationship between MS and sleep disturbances. By offering an understanding of the intricate interplay between the glymphatic system and MS, this review provides valuable insights which may lead to improved diagnostic techniques and more effective therapeutic interventions.

Comprehensive assessment of sleep duration, insomnia, and brain structure within the UK Biobank cohort

STUDY OBJECTIVES

To assess for associations between sleeping more than or less than recommended by the National Sleep Foundation (NSF), and self-reported insomnia, with brain structure.

METHODS

Data from the UK Biobank cohort were analyzed (N between 9K and 32K, dependent on availability, aged 44 to 82 years). Sleep measures included self-reported adherence to NSF guidelines on sleep duration (sleeping between 7 and 9 hours per night), and self-reported difficulty falling or staying asleep (insomnia). Brain structural measures included global and regional cortical or subcortical morphometry (thickness, surface area, volume), global and tract-related white matter microstructure, brain age gap (difference between chronological age and age estimated from brain scan), and total volume of white matter lesions.

RESULTS

Longer-than-recommended sleep duration was associated with lower overall grey and white matter volumes, lower global and regional cortical thickness and volume measures, higher brain age gap, higher volume of white matter lesions, higher mean diffusivity globally and in thalamic and association fibers, and lower volume of the hippocampus. Shorter-than-recommended sleep duration was related to higher global and cerebellar white matter volumes, lower global and regional cortical surface areas, and lower fractional anisotropy in projection fibers. Self-reported insomnia was associated with higher global gray and white matter volumes, and with higher volumes of the amygdala, hippocampus, and putamen.

CONCLUSIONS

Sleeping longer than recommended by the NSF is associated with a wide range of differences in brain structure, potentially indicative of poorer brain health. Sleeping less than recommended is distinctly associated with lower cortical surface areas. Future studies should assess the potential mechanisms of these differences and investigate long sleep duration as a putative marker of brain health.

Analysis of the correlation between immune cell characteristics and insomnia: a Mendelian randomization study

Insomnia, recognized as a prevalent sleep disorder, has garnered extensive attention within the realm of public health. Recent studies indicate a close interaction between the immune system and sleep; however, the specific mechanism remains not yet fully understood. Based on the publicly available Genome-Wide Association Study (GWAS) data, we used two-sample Mendelian randomization (MR) analyses to investigate the associations between 731 immune cell traits and insomnia risk. Five MR analysis methods and a comprehensive sensitivity analysis were used to evaluate the reliability of the results. In this study, we identified that 14 immune characteristics among four immune profiles [median fluorescence intensity (MFI), relative cell count (RC), absolute cell count (AC), and morphological parameters (MP)] demonstrated a significant causal association with insomnia. Specifically, eight immune cell characteristics were associated with an increased risk of insomnia, including CD11c+ monocyte% (P < 0.001), CD11c+ HLA DR++ monocyte% (P = 0.004), CD86+ plasmoid dendritic cell (DC) AC (P < 0.001), CD33br HLA DR+ CD14dim AC (P < 0.001), CD8dim AC (P = 0.002), CCR2 on CD14+ CD16- monocyte (P < 0.001), CD39 on monocyte (P < 0.001), and SSC-A on myeloid DC (P < 0.001). Six immune cell characteristics demonstrated protective effects against insomnia, including PB/PC %B cell (P < 0.001), CM CD4+% CD4+ (P < 0.001), T-cell AC (P < 0.001), BAFF-R on IgD- CD38br (P < 0.001), CD16-CD56 on HLA DR+ NK cells (P < 0.001), and CD14 on CD33br HLA DR+ CD14dim (P < 0.001). Our study established the correlation between immune cell characteristics and insomnia, offering a novel theoretical foundation for the concept of sleep-immune cross talk.NEW & NOTEWORTHY This study investigated the association between 731 immune cell characteristics and insomnia using Mendelian randomization, revealing that 14 immune cell characteristics across four groups of immune traits (MFI, RC, AC, and MP) have a significant and causal association with insomnia risk. Our results contribute to the understanding of the sleep-immune cross talk doctrine and offer a new theoretical basis for immune modulation in treating insomnia.

Identification of sleep and circadian alternative polyadenylation sites associated with APA-linked human brain disorders

Sleep and circadian rhythm disruptions are comorbid features of many pathologies and can negatively influence numerous health conditions, including degenerative diseases, metabolic illnesses, cancer, and various neurological disorders. Genetic association studies linking sleep and circadian disturbances with disease susceptibility have mainly focused on changes in gene expression due to mutations, such as single-nucleotide polymorphisms. Thus, associations between sleep and/or circadian rhythm and alternative polyadenylation (APA), particularly in the context of other health challenges, are largely undescribed. APA is a process that generates various transcript isoforms from the same gene, resulting in effects on mRNA translation, stability, localization, and subsequent function. Here, we have identified unique APAs in rat brain that exhibit time-of-day-dependent oscillations in expression as well as APAs that are altered by sleep deprivation and the subsequent recovery period. Genes affected by APA usage include Mapt/Tau, Ntrk2, Homer1A, Sin3band Sorl. Sorl1 has two APAs which cycle with a 24 h period, one additional APA cycles with a 12 h period and one more that is reduced during recovery sleep. Finally, we compared sleep- or circadian-associated APAs with recently described APA-linked brain disorder susceptibility genes and found 46 genes in common.

Exercise leads to better sleep in children with inflammatory bowel disease

BACKGROUND

The aim of our study was to investigate the effect of an exercise program on health-related quality of life (HRQoL) and sleep quality in children with inflammatory bowel disease (IBD) in remission.

METHODS

A total of 42 pediatric IBD patients in remission were recruited to participate in a 6-month-long home-based exercise program. Their mean age was 15.3 years (with a range of ± 2.08 years) and there were 25 boys. With regard to disease type, 22 had Crohn's disease (CD), 18 had ulcerative colitis (UC), and two had unclassified inflammatory bowel disease (IBD-U). Prior to starting the program, and after its completion, HRQoL was assessed using the IMPACT III questionnaire, and sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Patients also wore a triaxial accelerometer for 5 consecutive days before and after the completion of the exercise program to assess physical activity (PA) objectively.

RESULTS

Study participants experienced no significant increase in their IMPACT III score (from 147.6 ± 2.7 to 149.6 ± 2.7, p = 0.106) following the completion of the exercise program. The prevalence of impaired sleep quality (PSQI > 5) decreased significantly from 30.9 to 23.8% (p = 0.027). At the baseline, participants' time spent in light PA (LPA) correlated positively with their IMPACT III score (coefficient (coef.) 0.398, p = 0.013). Following the completion of the resistance training program, the changes in the IMPACT III score correlated positively with time spent in moderate-to-vigorous PA (MVPA) (coef. 0.329, p = 0.047) and negatively with changes in PSQI score (coef. -0.493, p = 0.001).

CONCLUSION

The number of children with impaired sleep quality decreased significantly following the completion of a 6-month-long home-based resistance training program but improvements in HRQoL scores did not reach statistical significance.