Sleep Mechanisms Research Articles

The Role of Interactions along the Brain–Gut–Microbiome Axis in the Regulation of Circadian Rhythms, Sleep Mechanisms, and Their Disorders

The Role of Interactions along the Brain–Gut–Microbiome Axis in the Regulation of Circadian Rhythms, Sleep Mechanisms, and Their Disorders

Developing forebrain synapses are uniquely vulnerable to sleep loss

Sleep is an essential behavior that supports lifelong brain health and cognition. Neuronal synapses are a major target for restorative sleep function and a locus of dysfunction in response to sleep deprivation (SD). Synapse density is highly dynamic during development, becoming stabilized with maturation to adulthood, suggesting sleep exerts distinct synaptic functions between development and adulthood. Importantly, problems with sleep are common in neurodevelopmental disorders including autism spectrum disorder (ASD). Moreover, early life sleep disruption in animal models causes long-lasting changes in adult behavior. Divergent plasticity engaged during sleep necessarily implies that developing and adult synapses will show differential vulnerability to SD. To investigate distinct sleep functions and mechanisms of vulnerability to SD across development, we systematically examined the behavioral and molecular responses to acute SD between juvenile (P21 to P28), adolescent (P42 to P49), and adult (P70 to P100) mice of both sexes. Compared to adults, juveniles lack robust adaptations to SD, precipitating cognitive deficits in the novel object recognition task. Subcellular fractionation, combined with proteome and phosphoproteome analysis revealed the developing synapse is profoundly vulnerable to SD, whereas adults exhibit comparative resilience. SD in juveniles, and not older mice, aberrantly drives induction of synapse potentiation, synaptogenesis, and expression of perineuronal nets. Our analysis further reveals the developing synapse as a putative node of convergence between vulnerability to SD and ASD genetic risk. Together, our systematic analysis supports a distinct developmental function of sleep and reveals how sleep disruption impacts key aspects of brain development, providing insights for ASD susceptibility.

Stress is simultaneously related to sleep and temporomandibular disorders.

This study aimed to clarify the relationship between the oral environment and psychological factors as predictor variables of sleep quality, in addition to inferring the relevant mechanisms of sleep and temporomandibular disorders (TMDs) by analyzing the relationship between TMDs and stress. This cross-sectional study analyzed data from 1,032 participants, comprising 420 men and 612 women, from the 2017 Iwaki Health Promotion Project using multiple regression analysis. The primary endpoints were the scores of each item in the Pittsburgh Sleep Quality Index (PSQI) and its sum. Predictor variables included the number of teeth; TMDs; stress, assessed using the World Health Organization-5 (WHO-5); sleep bruxism; and oral health-related quality of life, assessed using the oral health impact profile-14 (OHIP14). The confounding factors included age, body mass index, and alcohol intake. Multiple regression analysis revealed that TMDs (β value = 0.293, p = 0.034) and stress (β value = 1.3, p < 0.001) were significantly correlated with the PSQI total score. In addition, TMDs were significantly correlated with stress (β value = 0.076, p = 0.007). The significant relationship between sleep and TMDs suggests that mental stress contributes to the development sleep disorders and consequently is associated with the development of TMD symptoms.

Coupling observational study with computational toxicology to elucidate the relationships and potential mechanisms of per-and polyfluoroalkyl substances and sleep

Coupling observational study with computational toxicology to elucidate the relationships and potential mechanisms of per-and polyfluoroalkyl substances and sleep

The Triad of Sleep, Immunity, and Cancer: A Mediating Perspective.

The triadic interplay between sleep, immunity, and cancer represents a growing area of biomedical research with significant clinical implications. This review synthesizes the current knowledge on how sleep influences immune function, the immune system's role in cancer dynamics, and the direct connections between sleep patterns and cancer risk. After a comprehensive overview of the interrelationships among these three domains, the mechanisms of sleep in immune function are described, detailing how sleep regulates the immune system, the effects of sleep duration and quality on immune responses, and the underlying molecular and cellular mechanisms. Also, the complex relationship between immunity and cancer is explored, highlighting the immune system's role in cancer prevention and progression, immune surveillance, tumor microenvironment, and the implications of immunodeficiency and immune modulation on cancer risk. The direct connections between sleep and cancer are then described, presenting epidemiological evidence linking sleep patterns to cancer risk, biological mechanisms that influence cancer development, and the role of sleep disorders in cancer prognosis. The mediating role of sleep between immunity and cancer is highlighted, proposing hypothesized pathways, summarizing evidence from experimental and clinical studies, and evaluating the impact of sleep interventions on immune function and cancer outcomes. This review concludes by discussing the clinical implications and future directions, emphasizing the potential for sleep-based interventions in cancer prevention and treatment, the integration of sleep management in oncology and immunotherapy, and outlining a future research agenda. This agenda includes understanding the mechanisms of the sleep-immunity-cancer interplay, conducting epidemiological studies on sleep and cancer risk, assessing the impact of sleep management in cancer treatment protocols, exploring sleep and tumor microenvironment interactions, and considering policy and public health implications. Through a detailed examination of these interconnected pathways, this review underscores the critical importance of sleep in modulating immune function and cancer outcomes, advocating for interdisciplinary research and clinical strategies to harness this knowledge for improved health outcomes.

UP165, standardized corn leaf extract and its active component 6-methoxybenzoxazolinone induce non-rapid eye movement sleep through melatonergic and GABAergic mechanisms

The aim of this study was to investigate the sleep-promoting effects of corn leaf extract (UP165) and its active component 6-methoxybenzoxazolinone (6-MBOA), along with the underlying mechanisms in rodent models. Sleep activity in UP165 was measured by measuring sleep duration in the pentobarbital induced sleep model, and sleep quality was evaluated through electroencephalogram (EEG) analysis. In addition, the sleep mechanism was analyzed through an in vivo sleep study co-administrated with receptor antagonists. The administrations of both UP165 and 6-MBOA effectively increased sleep duration, demonstrating a 3-fold increase sleep time at 100 mg/kg UP165 and a 2.3-fold increase at 280 μg/kg 6-MBOA compared to those of the control group. The sleep-promoting effect of UP165 was also observed in the caffeine-induced insomnia model, resulting in a 71.6% increase in sleep duration. The UP165-mediated increase in sleep time was attributed to enhanced non-rapid eye movement (NREM) sleep, specifically an increase in the δ-wave sleep measured by EEG. Mechanism analysis with co-administration of competitive antagonists in vivo revealed that UP165 and 6-MBOA enhanced sleep duration through binding to gamma-aminobutyric acid type A (GABAA) and melatonin receptors. Oral administration of UP165 for 4 weeks effectively increased both gene expression and protein levels of GABAA, melatonin 1A, and melatonin 1B receptors. High-dose administration of UP165 significantly decreased the blood level of corticosterone, while concurrently increased GABA, serotonin, and melatonin levels in brain. This study highlights the potential of UP165 and 6-MBOA as edible-grade natural ingredients for sleep promotion.

The Connection Between Mental Performance and Sleep

Although our understanding of sleep physiology is growing, and many of the mechanisms of sleep have been explained, studies have focused on the effect of sleep on learning and memory processes due to the increase in sleep after learning. However, it is still unclear what kind of information processing occurs in the brain during sleep and what effects of information processing-related events are transferred from wakefulness to sleep. Research on information processing during sleep suggests that sleep has a positive impact on memory function. However, it is unclear whether specific sleep stages, such as NREM and REM, are exclusively dedicated to certain types of memory, such as semantic or event memory. When evaluating the research and approaches discussed above, it can be concluded that information processing occurs during sleep. However, it is important to note the limitations of studying information processing during sleep due to the challenges of conducting research in this state. Despite spending a third of our lives asleep, our understanding of the benefits of sleep remains limited. It is a fact that information processing occurs during sleep. It is a fact that information processing occurs during sleep. However, studies investigating this phenomenon are limited. Research on sleep, memory, and information processing can help us understand learning, consciousness, and memory processes during sleep, as well as the function of sleep neurophysiology.

Assessing sleep in primary brain tumor patients using smart wearables and patient-reported data: Feasibility and interim analysis of an observational study.

Sleep-wake disturbances are common and disabling in primary brain tumor (PBT) patients but studies exploring longitudinal data are limited. This study investigates the feasibility and relationship between longitudinal patient-reported outcomes (PROs) and physiologic data collected via smart wearables. Fifty-four PBT patients ≥ 18 years wore Fitbit smart-wearable devices for 4 weeks, which captured physiologic sleep measures (eg, total sleep time, wake after sleep onset [WASO]). They completed PROs (sleep hygiene index, PROMIS sleep-related impairment [SRI] and Sleep Disturbance [SD], Morningness-Eveningness Questionnaire [MEQ]) at baseline and 4 weeks. Smart wearable use feasibility (enrollment/attrition, data missingness), clinical characteristics, test consistency, PROs severity, and relationships between PROs and physiologic sleep measures were assessed. The majority (72%) wore their Fitbit for the entire study duration with 89% missing < 3 days, no participant withdrawals, and 100% PRO completion. PROMIS SRI/SD and MEQ were all consistent/reliable (Cronbach's alpha 0.74-0.92). Chronotype breakdown showed 39% morning, 56% intermediate, and only 6% evening types. Moderate-severe SD and SRI were reported in 13% and 17% at baseline, and with significant improvement in SD at 4 weeks (P = .014). Fitbit-recorded measures showed a correlation at week 4 between WASO and SD (r = 0.35, P = .009) but not with SRI (r = 0.24, P = .08). Collecting sleep data with Fitbits is feasible, PROs are consistent/reliable, > 10% of participants had SD and SRI that improved with smart wearable use, and SD was associated with WASO. The skewed chronotype distribution, risk and impact of sleep fragmentation mechanisms warrant further investigation. NCT04 669 574.

Improvement of sleep duration and quality through GABAA receptor by whey protein hydrolysate containing DIQK as the main active compound

This study characterized the sleep activity, sleep mechanism, and active peptides of whey protein hydrolysates selected through behavioral analysis of fruit flies (Drosophila melanogaster). Sleep-inducing whey protein (WP) hydrolysate was selected through fruit fly behavior analysis, and sleep activity was measured using a pentobarbital model and electroencephalographic analysis. The mechanism of action was confirmed using a γ-aminobutyric acid (GABA) receptor antagonist, and the active peptide was identified using liquid chromatography-mass spectrometry. Whey protein hydrolysate, prepared using Alcalase and Prozyme (WP-AP), increased sleep time in a dose-dependent manner. The WP-AP significantly increased not only sleep time but also slow-wave sleep and showed an insomnia-alleviating effect in a caffeine-induced insomnia mouse model. In addition, the gene and protein expression levels of GABA subtype A receptors increased in the brains of mice orally administered with WP-AP. Through peptide analysis, the mixture of DIQK, VPPF peptide, and GABA contained in WP-AP was estimated to exhibit sleep activity, and due to its high content, DIQK was speculated to be the main sleep-inducing ingredient. These results indicate that WP-AP has the potential to be used as a new ingredient to improve sleep quality.

Energy-efficient indoor hybrid deployment strategy for 5G mobile small-cell base stations using JAFR Algorithm

In the context of 5th-generation (5G) mobile communication technology, deploying indoor small-cell base stations (SBS) to serve visitors has become common. However, indoor SBS is constrained by factors such as service capacity, signal interference, and structural layout. Merchants within large buildings frequently host diverse activities to attract visitors, significantly increasing indoor traffic and crowd-gathering phenomenon. Consequently, SBS faces challenges of excessive energy consumption, compromised communication quality, and an inability to provide service to all visitors. Merchants aim to deploy SBS that can effectively curtail energy consumption costs while fulfilling visitor needs. However, due to the intermittent nature of high footfall situations, employing additional fixed SBS is not economically viable. Therefore, we address the challenge of maintaining service quality and mitigating energy consumption of SBS during footfall fluctuations by proposing an SBS model with a dynamic sleep mechanism. We simulate the internal structure of a three-dimensional (3D) building and the footfall over time. Within this model, we leverage the flexibility of mobile small-cell base stations (MSBS) to seamlessly traverse service regions. We compute the transmission power and location of SBS and MSBS based on energy efficiency (EE), combining their strengths to tackle the challenge. This approach maintains SBS communication quality while curbing energy consumption. We attain the optimal hybrid deployment strategy by enhancing the adaptive differential evolution with optional external archive (JADE) algorithm and incorporating the final fitness formula, the adaptive ranking mutation operator strategy, and the disorder replacement strategy (DRS) in it to form the proposed joint adaptive fusion with ranking (JAFR) algorithm. Our comparative simulation experiments demonstrate the effectiveness of JAFR in addressing the challenges against conventional methods, recent differential evolution algorithms, and mobile base station (MBS) deployment approaches posed by this model. The results indicate that the JAFR algorithm yields superior SBS deployment strategies in most cases.

Sleep Onset, Melatonin, and Cortisol Levels on Vegetarian and Non-Vegetarian Communities in Denpasar, Bali

Background. Sleep is a basic human need. Sleep disorders have become a concern in the health sector in recent decades. The type of food we consume considerably influences sleep biochemistry, including melatonin. Melatonin can trigger sleep by suppressing wake-promoting signals or neuronal firing in the Supra Chiasmatic Nucleus. The most explainable effect of melatonin's role in regulating sleep mechanisms is reducing sleep onset latency. The hormone cortisol is said to be a stress hormone as the end product of the Hypothalamic Pituitary Axis (HPA), which can disrupt sleep. No research has analyzed the differences in levels of these hormones and sleep onset in vegetarian and non-vegetarian groups. The study analyzed differences in melatonin, cortisol and sleep onset levels in vegetarian and non-vegetarian communities. Methods. This research was an analytical observational study using a cross-sectional method. The research was carried out after obtaining approval from the ethics commission. All subjects had their blood levels of melatonin and cortisol checked and sleep onset assessed using a sleep tool. The data collected was then analyzed for differences between the two groups. Results. This study involved 76 subjects from vegetarian (38) and non-vegetarian (38) groups. For the characteristics of the two groups, most of the subjects were less than 45 years old, married, had postgraduate education, and worked as private employees. Body weight was mainly average in both groups, but there was more overweight and obesity in the non-vegetarian group, namely 22.9% overweight compared to 21.1% in the vegetarian group. Obese in the non-vegetarian group was 15.8% compared to 7.9% in the vegetarian group, although this difference was not statistically significant (p=0.471). Cortisol levels in the non-vegetarian group were higher than those in the vegetarian group, although not statistically significant (p=0.779). Melatonin levels were higher in the vegetarian group, but this was not statistically significant (p=398). Most of the vegetarian group's sleep onset was less than 20 minutes, unlike the non-vegetarian group, whose sleep onset was more than 20 minutes. This condition is statistically significant with a p-value &lt;0.001. Conclusion. Cortisol or stress hormone levels were higher in the non-vegetarian group than in the vegetarian group. In contrast, melatonin or sleep hormone levels were higher in the vegetarian group, although neither condition was statistically significant. Clinically, the onset of sleep in the two groups was significantly different, where the vegetarian group had a faster onset of sleep than the non-vegetarian group. Keywords: melatonin levels, cortisol, sleep onset, vegetarian, non-vegetarian

Temporal cluster-based organization of sleep spindles underlies motor memory consolidation.

Sleep benefits motor memory consolidation, which is mediated by sleep spindle activity and associated memory reactivations during non-rapid eye movement (NREM) sleep. However, the particular role of NREM2 and NREM3 sleep spindles and the mechanisms triggering this memory consolidation process remain unclear. Here, simultaneous electroencephalographic and functional magnetic resonance imaging (EEG-fMRI) recordings were collected during night-time sleep following the learning of a motor sequence task. Adopting a time-based clustering approach, we provide evidence that spindles iteratively occur within clustered and temporally organized patterns during both NREM2 and NREM3 sleep. However, the clustering of spindles in trains is related to motor memory consolidation during NREM2 sleep only. Altogether, our findings suggest that spindles' clustering and rhythmic occurrence during NREM2 sleep may serve as an intrinsic rhythmic sleep mechanism for the timed reactivation and subsequent consolidation of motor memories, through synchronized oscillatory activity within a subcortical-cortical network involved during learning.

Pengaruh Pemberian Aromaterapi Lavender Terhadap Kualitas Tidur Lansia di UPT RPS Lanjut Usia Budhi Dharma Yogyakarta

Background: Aging is a natural process, one that will occur in all human systems and is characterized by progressive degeneration of both physical and psychic systems that will impact the quality of sleep. In older age these sleep mechanisms occur longer because of inability to start sleep, to maintain sleep, to get up early or to wake up with discomfort. One way to overcome the problem of sleep disorders is to use complementary therapy with aromatherapy. The effect of personal aromatherapy can be soothing and relaxing. Among the frequent aromatherapy is that lavender scent is commonly used to lower stress levels, headaches, burns, or lesions, muscle relaxant, and improve sleep quality. The purpose of this study is to understand the effects lavender's scent on the quality of sleep in the aged budhi dharma Yogyakarta. Methods: this type of research is an experimental quantitative study using pre exam design (one group pre test and post design test). Research is conducted on the upt RPS of the elderly budhi dharma yogykarta. The study's population is 60-76 years old and lives in homes of 61 people. The number of samples was 17 respondents with a total sampling technique. The instrument of this study uses the Pittsburgh sleep quality index (PSQI) questionnaire. Data analysis method Paired t-test specimen. Results: studies show that there is a significant difference in the quality of sleep for a respondents after lavender aromatherapy is given. This is proven by the independent t test, on the acquisition of p-value sleep quality 0,000 or 0.05.Conclusion: it may be concluded that there was a significant impact on the quality of sleep of the respondents after lavender aromatherapy was administered.

The interactions along the microbiota-gut-brain axis in the regulation of circadian rhythms, sleep mechanisms and disorders

The bidirectional relationship between cerebral structures and the gastrointestinal tract involving the microbiota embraces the scientific concept of the microbiota-gut-brain axis. The gut microbiome plays an important role in many physiological and biochemical processes of the human body, in the immune response and maintenance of homeostasis, as well as in the regulation of circadian rhythms. There is a relationship between the higher prevalence of a number of neurological disorders, sleep disorders and changes in the intestinal microbiota, which actualizes the study of the complex mechanisms of such correlation for the development of new treatment and prevention strategies. Environmental factors associated with excessive light exposure can aggravate the gut dysbiosis of intestinal microflora, and as a result, lead to sleep disturbances. This review examines the integrative mechanisms of sleep regulation associated with the gut microbiota (the role of neurotransmitters, short-chain fatty acids, unconjugated bile acids, bacterial cell wall components, cytokines). Taking into account the influence of gut dysbiosis as a risk factor in the development of various diseases, the authors systematize key aspects and modern scientific data on the importance of microflora balance to ensure optimal interaction along the microbiota-gut-brain axis in the context of the regulatory role of the sleep-wake cycle and its disorders.

Adaptive sleep scheduling in heterogeneous WSN using GWO for energy efficiency

Wireless Sensor Networks are instrumental in various domains, including environmental monitoring, healthcare, and industrial automation. Despite their ubiquity, the energy constraints of sensor nodes remain a pivotal concern. This research delves into energy conservation in WSNs by implementing Adaptive Sleep Scheduling using the Grey Wolf Optimizer (GWO) in the context of heterogeneous networks. Heterogeneous WSNs, characterized by nodes with diverse computational capacities and energy reservoirs, pose unique challenges for optimizing energy efficiency. The conventional static sleep scheduling strategies prove inadequate in accommodating this heterogeneity, often leading to suboptimal energy consumption. In this context, the application of GWO, an optimization algorithm inspired by the social behavior of grey wolves, offers a novel and promising approach to address the energy efficiency challenge. Heterogeneous WSNs necessitate tailored energy management strategies to optimize the utilization of resources. The disparity in the capabilities of sensor nodes, in terms of processing power and energy reserves, demands an adaptive solution for sleep scheduling to minimize energy consumption while maintaining the necessary data collection and transmission capabilities. This research demonstrates the significance of integrating GWO-based adaptive sleep scheduling in heterogeneous WSNs through extensive simulations and in-depth analysis. The proposed approach is compared with the LEACH, E-LEACH, and DEEC. The results show due to the use of GWO in adaptive sleep mechanisms in Heterogenous WSNs nodes die late as compared to other algorithms and energy consumption is also slow. So, in all one can say, GWO is a better approach in terms of energy efficiency and lifetime. quantity demand and investment in research and development, while the other model focuses on a more realistic relationship between the quantity demand and the price.

Optimization of Communication Base Station Battery Configuration Considering Demand Transfer and Sleep Mechanism under Uncertain Interruption Duration

In the communication power supply field, base station interruptions may occur due to sudden natural disasters or unstable power supplies. This work studies the optimization of battery resource configurations to cope with the duration uncertainty of base station interruption. We mainly consider the demand transfer and sleep mechanism of the base station and establish a two-stage stochastic programming model to minimize battery configuration costs and operational costs. To transform the uncertainty expression in the first stage into a deterministic model, we design the K-Means-SAA algorithm to accelerate problem-solving and to compare it with the SAA algorithm. The case study results indicate that the proposed two-stage stochastic programming model can save 17.02% of the total cost compared to the expected value model. The proposed demand transfer and sleep mechanism can reduce the total cost by 41.92% compared to no mechanism. The results of numerical experiments and sensitivity analysis also verify the superiority of the designed algorithm in terms of running efficiency and solving time. Therefore, the model and algorithm proposed in this work provide valuable application guidance for large-scale base station configuration optimization of battery resources to cope with interruptions in practical scenarios.

The role and mechanisms of sleep on memory consolidation

In addition to its physiological functions, sleep also has a consolidating effect on memory, and current research has found sleep could promote the consolidation of declarative, procedural, and emotional memory. Possible mechanisms of sleep-enhanced memory include the the systemic consolidation theory, dual-process theory, the synaptic homeostasis theory, and the sequence hypothesis. In the future, more research need to examine the neural mechanisms of sleep-enhanced memory consolidation, and the use of simultaneous EEG-MRI will be a meaningful attempt to help us better understand the specific neural processes of sleep-enhanced memory consolidation.

Sleep fragmentation affects glymphatic system through the different expression of AQP4 in wild type and 5xFAD mouse models

AbstractBackgroundSleep is an important physiological process, during which extracellular metabolic wastes, such as amyloid and tau protein, are cleared via paravascular pathway. Changes in the timing and structure of sleep occur across the lifespan. Increased sleep fragmentation and reductions in slow wave sleep (SWS) represent the hallmark signs of age‐related changes in sleep. The origin of sleep disturbances in AD is thought to be multifactorial. In the aging brain, the impairment of glymphatic pathway function slows the clearance of interstitial Aβ, rendering the aging brain vulnerable to neurodegenerative disease. Several authors have independently shown that glymphatic flux depends upon the expression and perivascular localization of the astroglial water channel aquaporin‐4 (AQP4).MethodIn this study, we performed and validated a mouse model of AD and chronic sleep fragmentation, a sleep disorder that mimics more correctly a real condition of intermittent and continuous awakening. We analyzed the effect of sleep fragmentation in wild type and 5xFAD mice. All the animals underwent to behavioral studies to analyze anxiety and spatial and working memory. We had validated sleep fragmentation and its effect through EEG and biomolecular analysis, by observing all the macro‐areas implied in sleep regulation.ResultWe noticed that sleep fragmentation induces a general acceleration of AD progression in 5xFAD mice, while in wild type mice it affects cognitive behaviors in particular learning and memory. Both these events may be correlated to AQP4 modulation, a crucial player of the glymphatic system activity. In particular, sleep fragmentation differentially affects AQP4 expression according to the stage of the disease, with an up‐regulation in younger animals, while such change cannot be detected in older ones. Moreover, in wild type mice sleep fragmentation affects cognitive behaviors, in particular learning and memory, by compromising the glymphatic system through the decrease of AQP4.ConclusionNevertheless, an in‐depth study is needed to better understand the mechanism by which AQP4 is modulated and whether it could be considered a risk factor for the disease development in wild type mice. If our hypotheses are going to be confirmed, AQP4 modulation may represent the convergence point between AD and sleep disorder pathogenic mechanisms

Associations of sleep duration and daytime sleepiness with plasma amyloid beta and cognitive performance in cognitively unimpaired, middle-aged and older African Americans.

Given the established racial disparities in both sleep health and dementia risk for African American populations, we assess cross-sectional and longitudinal associations of self-report sleep duration (SRSD) and daytime sleepiness with plasma amyloid beta (Aβ) and cognition in an African American (AA) cohort. In a cognitively unimpaired sample drawn from the African Americans Fighting Alzheimer's in Midlife (AA-FAiM) study, data on SRSD, Epworth Sleepiness Scale, demographics, and cognitive performance were analyzed. Aβ40, Aβ42, and the Aβ42/40 ratio were quantified from plasma samples. Cross-sectional analyses explored associations between baseline predictors and outcome measures. Linear mixed-effect regression models estimated associations of SRSD and daytime sleepiness with plasma Aβ and cognitive performance levels and change over time. One hundred and forty-seven participants comprised the cross-sectional sample. Baseline age was 63.2 ± 8.51 years. 69.6% self-identified as female. SRSD was 6.4 ± 1.1 hours and 22.4% reported excessive daytime sleepiness. The longitudinal dataset included 57 participants. In fully adjusted models, neither SRSD nor daytime sleepiness is associated with cross-sectional or longitudinal Aβ. Associations with level and trajectory of cognitive test performance varied by measure of sleep health. SRSD was below National Sleep Foundation recommendations and daytime sleepiness was prevalent in this cohort. In the absence of observed associations with plasma Aβ, poorer self-reported sleep health broadly predicted poorer cognitive function but not accelerated decline. Future research is necessary to understand and address modifiable sleep mechanisms as they relate to cognitive aging in AA at disproportionate risk for dementia. Not applicable.

The low ratio of ghrelin in plasma and cerebrospinal fluid might be beneficial to sleep

ObjectiveGhrelin is physiologically important for maintaining sleep rhythm. Cigarette smoking has been demonstrated to significantly increase the risk of insufficient sleep by regulating ghrelin at the central and peripheral levels. No research has been published to study the relationship between active smoking and sleep via ghrelin level in cerebrospinal fluid (CSF). MethodsA total of 139 Chinese males were recruited and divided into active smokers (n = 77) and non-smokers (n = 62). The levels of CSF and plasma ghrelin were measured. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep. ResultsNon-smokers had lower PSQI scores (1.71 ± 1.93) than active smokers (3.70 ± 1.78). Non-smokers have significantly lower plasma ghrelin levels and lower plasma/CSF ghrelin ratio but higher CSF ghrelin than active smokers. Among non-smokers, plasma ghrelin levels were not correlated with PSQI scores (all p > 0.05), CSF ghrelin levels were positively correlated with PSQI scores (r = 0.309, p = 0.019), and the plasma/CSF ghrelin ratio was negatively correlated with PSQI scores (r = −0.346, p = 0.008). ConclusionsThis study is the first to reveal the relationship between cigarette smoking, high CSF ghrelin levels and insufficient sleep, suggesting that maintaining a normal plasma/CSF ghrelin ratio may be the physiological mechanism of healthy sleep, and the insufficient sleep population must quit smoking.