Naturally Occurring Consecutive Sleep Loss and Day-to-Day Trajectories of Affective and Physical Well-Being.

BACKGROUND: Experimental studies have shown that just 1 night of sleep loss impairs next-day performance, mood, and energy. Yet, little is known about the effects of consecutive sleep loss on daily well-being in participants' own settings. PURPOSE: This study examined whether and how naturally occurring consecutive sleep loss is associated with day-to-day trajectories of affective and physical well-being. METHODS: Participants were adults (N = 1,958) from the Midlife in the United States Study who provided daily diary data for eight consecutive days. Consecutive sleep loss was operationalized as the within-person number of consecutive nights with <6 hr of sleep. Multilevel models evaluated the linear, quadratic, and cubic effects of consecutive sleep loss on daily well-being, after controlling for sociodemographic, health, and daily covariates. RESULTS: Daily negative affect increased and positive affect decreased in curvilinear fashion as the number of consecutive sleep loss increased. For example, daily negative affect increased (linear), but the rate of increase decelerated as the number of consecutive sleep loss increased (quadratic). Results were consistent for the number and severity of physical symptoms. For negative affect and the severity of physical symptoms, cubic effect was also significant such that the rate of increase accelerated again in the days most distal to baseline (no sleep loss). CONCLUSIONS: Consecutive sleep loss was associated with degraded trajectories of daily affective and physical well-being. Making efforts to break the vicious cycle of sleep loss may protect daily well-being in adults whose sleep time is often compromised.

Extending sleep to confirm insufficient sleep syndrome is challenging.

Insufficient sleep syndrome (ISS) is prevalent, but poorly studied. This descriptive study was performed to determine its diagnostic challenges and clinical characteristics in a large (n = 3,461) retrospective sample from a single sleep laboratory. Based on actigraphy, polysomnography and multiple sleep latency tests, we diagnosed "suspected insufficient sleep syndrome" in patients with chronic sleepiness, short time in bed, longer sleep duration during weekends or vacation, and without evidence of other causes of sleepiness. For the diagnosis of "definite insufficient sleep syndrome", we additionally required objectively confirmed resolution of sleepiness with actigraphy-documented extension of time in bed. We diagnosed "suspected insufficient sleep syndrome" in 300 subjects. In 94 subjects, extension of sleep time with consecutive relief of sleepiness was attempted, but only 37 subjects succeeded, often despite being offered several attempts. "Definite insufficient sleep syndrome" was confirmed in 36 patients. In these subjects, mean time in bed after sleep extension was above 8 hr per night and 84 min longer than at baseline. Narcolepsy-like findings were frequently observed before sleep extension, but no sleep onset rapid eye movement sleep on polysomnography. This study indicates that fulfilling the diagnostic criteria of ISS is challenging in clinical practice. It further corroborates the importance of actigraphy and polysomnography for correct diagnosis.

Chronic Sleep Restriction Induces Aß Accumulation by Disrupting the Balance of Aß Production and Clearance in Rats.

Amyloid-ß (Aß) plays an important role in Alzheimer's disease (AD) pathogenesis, and growing evidence has shown that poor sleep quality is one of the risk factors for AD, but the mechanisms of sleep deprivation leading to AD have still not been fully demonstrated. In the present study, we used wild-type (WT) rats to determine the effects of chronic sleep restriction (CSR) on Aß accumulation. We found that CSR-21d rats had learning and memory functional decline in the Morris water maze (MWM) test. Meanwhile, Aß42 deposition in the hippocampus and the prefrontal cortex was high after a 21-day sleep restriction. Moreover, compared with the control rats, CSR rats had increased expression of ß-site APP-cleaving enzyme 1 (BACE1) and sAPPß and decreased sAPPα levels in both the hippocampus and the prefrontal cortex, and the BACE1 level was positively correlated with the Aß42 level. Additionally, in CSR-21d rats, low-density lipoprotein receptor-related protein 1 (LRP-1) levels were low, while receptor of advanced glycation end products (RAGE) levels were high in the hippocampus and the prefrontal cortex, and these transporters were significantly correlated with Aß42 levels. In addition, CSR-21d rats had decreased plasma Aß42 levels and soluble LRP1 (sLRP1) levels compared with the control rats. Altogether, this study demonstrated that 21 days of CSR could lead to brain Aß accumulation in WT rats. The underlying mechanisms may be related to increased Aß production via upregulation of the BACE1 pathway and disrupted Aß clearance affecting brain and peripheral Aß transport.

Chronic sleep restriction promotes brain inflammation and synapse loss, and potentiates memory impairment induced by amyloid-ß oligomers in mice.

It is increasingly recognized that sleep disturbances and Alzheimer's disease (AD) share a bidirectional relationship. AD patients exhibit sleep problems and alterations in the regulation of circadian rhythms; conversely, poor quality of sleep increases the risk of development of AD. The aim of the current study was to determine whether chronic sleep restriction potentiates the brain impact of amyloid-ß oligomers (AßOs), toxins that build up in AD brains and are thought to underlie synapse damage and memory impairment. We further investigated whether alterations in levels of pro-inflammatory mediators could play a role in memory impairment in sleep-restricted mice. We found that a single intracerebroventricular (i.c.v.) infusion of AßOs disturbed sleep pattern in mice. Conversely, chronically sleep-restricted mice exhibited higher brain expression of pro-inflammatory mediators, reductions in levels of pre- and post-synaptic marker proteins, and exhibited increased susceptibility to the impact of i.c.v. infusion of a sub-toxic dose of AßOs (1pmol) on performance in the novel object recognition memory task. Sleep-restricted mice further exhibited an increase in brain TNF-α levels in response to AßOs. Interestingly, memory impairment in sleep-restricted AßO-infused mice was prevented by treatment with the TNF-α neutralizing monoclonal antibody, infliximab. Results substantiate the notion of a dual relationship between sleep and AD, whereby AßOs disrupt sleep/wake patterns and chronic sleep restriction increases brain vulnerability to AßOs, and point to a key role of brain inflammation in increased susceptibility to AßOs in sleep-restricted mice.

Chronic sleep loss alters the inflammatory response and BDNF expression in C57BL/6J mice.

Although adequate sleep is imperative for proper physiological function, over one-third of US adults obtain insufficient sleep. The current research investigated the impact of chronic sleep restriction (CSR) on inflammatory markers and hippocampal BDNF mRNA, following an immune insult in both male and female mice. Patterns of cytokine expression were different when the study was done in males vs. females, indicating potential sex differences in the inflammatory response following CSR. Further, CSR led to suppressed hippocampal BDNF expression in males, an effect not observed in females. These data suggest a complex interaction between chronic sleep loss, inflammation, and sex that warrants further exploration.

Dynamics of recovery sleep from chronic sleep restriction.

Sleep loss is common in our 24/7 society with many people routinely sleeping less than they need. Sleep debt is a term describing the difference between the amount of sleep needed, and the amount of sleep obtained. Sleep debt can accumulate over time, resulting in poor cognitive performance, increased sleepiness, poor mood, and a higher risk for accidents. Over the last 30 years, the sleep field has increasingly focused attention on recovery sleep and the ways we can recover from a sleep debt faster and more effectively. While there are still many unanswered questions and debates about the nature of recovery sleep, such as the exact components of sleep important for recovery of function, the amount of sleep needed to recover and the impacts of prior sleep history on recovery, recent research has revealed several important attributes about recovery sleep: (1) the dynamics of the recovery process is impacted by the type of sleep loss (acute versus chronic), (2) mood, sleepiness, and other aspects of cognitive performance recover at different rates, and (3) the recovery process is complex and dependent on the length of recovery sleep and the number of recovery opportunities available. This review will summarize the current state of the literature on recovery sleep, from specific studies of recovery sleep dynamics to napping, "banking" sleep and shiftwork, and will suggest the next steps for research in this field. This paper is part of the David F. Dinges Festschrift Collection. This collection is sponsored by Pulsar Informatics and the Department of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania.

[Chronic sleep restriction in rats leads to a weakening of compensatory reactions in response to acute sleep deprivation]. / Khronicheskoe ogranichenie sna u krys privodit k oslableniyu kompensatornykh reaktsii v otvet na ostruyu deprivatsiyu sna.

OBJECTIVE: To identify features in the compensatory mechanisms of sleep regulation in response to acute sleep deprivation after chronic sleep restriction in rats. MATERIAL AND METHODS: Male Wistar rats 7-8 months old underwent 5-day sleep restriction: 3 h of sleep deprivation and 1 h of sleep opportunity repeating throughout each day. Six-hour acute total sleep deprivation was performed at the beginning of daylight hours on the 3rd day after sleep restriction. Polysomnogramms were recorded throughout the day before chronic sleep restriction, on the 2nd recovery day after chronic sleep restriction and after acute sleep deprivation. The control group was not subjected to chronic sleep restriction. RESULTS: The animals after chronic sleep restriction had the compensatory increase in total sleep time in response to acute sleep deprivation weaker than in control animals. Animals after sleep restriction had the compensatory increase in the time of slow-wave sleep (SWS) only in the first 6 hours after acute sleep deprivation, whereas in control animals the period of compensation of SWS lasted 12 hours. A compensatory increase in slow-wave activity (SWA) was observed in both groups of animals, but in animals experiencing chronic sleep restriction the amplitude of SWA after acute sleep deprivation was less than in control animals. A compensatory increase in REM sleep in sleep restricted animals occurred immediately after acute sleep deprivation and coincides with a compensatory increase in SWS and SWA, whereas in control conditions these processes are spaced in time. CONCLUSION: Compensatory reactions in response to acute sleep deprivation (sleep homeostasis) are weakened in animals subjected to chronic sleep restriction, as the reaction time and amplitude are reduced.

Involvement of Paired Immunoglobulin-Like Receptor B in Cognitive Dysfunction Through Hippocampal-Dependent Synaptic Plasticity Impairments in Mice Subjected to Chronic Sleep Restriction.

Sleep loss is often associated with cognitive dysfunction. Alterations in the structure and function of synapses in the hippocampus are thought to underlie memory storage. Paired immunoglobulin-like receptor B (PirB) plays a negative role in various neurological diseases by inhibiting axon regeneration and synaptic plasticity. However, the contributions of PirB to the mechanisms underlying the changes in synaptic plasticity after sleep loss that ultimately promote deficits in cognitive function have not been well elucidated. Here, we showed that chronic sleep restriction (CSR) mice displayed cognitive impairment and synaptic deficits accompanied by upregulation of PirB expression in the hippocampus. Mechanistically, PirB caused the dysregulation of actin through the RhoA/ROCK2/LIMK1/cofilin signalling pathway, leading to abnormal structural and functional plasticity, which in turn resulted in cognitive dysfunction. PirB knockdown alleviated synaptic deficits and cognitive impairment after CSR by inhibiting the RhoA/ROCK2/LIMK1/cofilin signalling pathway. Moreover, we found that fasudil, a widely used ROCK2 inhibitor, could mimic the beneficial effect of PirB knockdown and ameliorate synaptic deficits and cognitive impairment, further demonstrating that PirB induced cognitive dysfunction after CSR via the RhoA/ROCK2/LIMK1/cofilin signalling pathway. Our study sheds new light on the role of PirB as an important mediator in modulating the dysfunction of synaptic plasticity and cognitive function via the RhoA/ROCK2/LIMK1/cofilin signalling pathway, which indicated that hippocampal PirB is a promising therapeutic target for counteracting cognitive impairment after CSR. This illustration depicts the signalling pathway by PirB in mediating cognitive impairment and synaptic deficits in CSR mice. In the hippocampus of CSR mice, the expression level of PirB was significantly increased. In addition, CSR increases RhoA and ROCK2 levels and reduces levels of both LIMK1 and cofilin phosphorylation. PirB knockdown reverses cognitive impairment and synaptic plasticity disorders caused by CSR through the RhoA/ROCK2/LIMK1/cofilin signalling pathway.

Down-regulating insulin-like growth factor-1 receptor reduces amyloid-ß deposition in mice cortex induced by chronic sleep restriction.

OBJECTIVE: Insufficient sleep affects cognitive function, but the underlying mechanism and potential protective ways are yet to be fully understood. This study aimed to explore the influence of chronic sleep restriction (CSR) on the insulin-like growth factor-1 (IGF-1) signaling pathway, and whether down-regulating IGF-1 signaling pathway would modulate amyloid-ß (Aß) peptides metabolism and its cortical deposition after CSR. Methods 8-week IGF-1R+/- mice and wild-type (WT) C57BL/6 (C57) mice were divided into four groups: IGF-1R+/- CSR (MUSR), IGF-1R+/- control (MUCO), C57 CSR (C57SR) and C57 control (C57CO). CSR model was established by application of slowly rotating drum for 2 months. Body weight and Lee's index were measured. The level of IGF-1 in plasma was measured by enzyme linked immunosorbent assay (ELISA). Aß accumulation was detected by immunofluorescence. The expressions of amyloid precursor protein (APP), ß-site amyloid precursor protein-cleaving enzyme-1 (BACE-1) and C99 were detected using western-blot (WB). Results Two-way ANOVA showed genotypic effect was significant on body weight and Lee's index. Neither treatment effect nor interaction reached significant difference on body weight and Lee's index. The level of IGF-1 in plasma was significantly decreased in C57SR compared with C57CO. Besides, compared with C57CO, Aß was markedly accumulated in frontal cortex, in parallel with increased expressions of BACE-1 and C99, and with no difference of APP in C57SR group. Further, no significant changes of Aß, BACE-1, C99 and APP were detected in MUSR compared with MUCO. Conclusions This study showed that CSR could induce the decrease of circulating IGF-1 in mice. By using the IGF-1R+/- mice, we found that down-regulating IGF-1R could reduce Aß deposition in mice frontal cortex after CSR via inhibiting BACE-1 protein expression and activity, which were independent of the changes of body weight and Lee's index. These findings indicate that the blockage of IGF-1 signaling pathway might be a protection mechanism for alleviating the impact of CSR.

Impact of chronic sleep restriction on sleep continuity, sleep structure, and neurobehavioral performance.

Chronic sleep restriction (CSR) has been associated with adverse effects including cognitive impairment and increased risk of diabetes and cardiovascular disease. Yet, sleep restriction therapy is an essential component of most behavioral treatments for insomnia. Moreover, little is known about the impact of CSR on sleep continuity and structure in healthy people whose need for sleep is satiated. We investigated the impact of CSR on sleep continuity and structure in nine healthy participants. They had 4 nights of sleep extension, 2 nights of post-extension sleep, 21 nights of CSR (5/5.6-hour time-in-bed), and 9 nights of recovery sleep. Compared to postextension sleep, during CSR sleep duration was reduced by 95.4 ±â€…21.2 min per night, Slow-Wave Activity was significantly increased, and sleep was more consolidated. During recovery, sleep duration was increased by 103.3 ±â€…23.8 min compared to CSR, and the CSR-induced increase in Slow-Wave Activity persisted, particularly after the 5-hour exposure. Yet, we found that sustained vigilant attention was not fully recovered even after nine nights of recovery sleep. Our results suggest that CSR improves traditional metrics of sleep quality and may have a persistent impact on sleep depth, which is consistent with the reported benefits on sleep continuity and structure of sleep restriction therapy. However, these improvements in traditional metrics of sleep quality were associated with deterioration rather than improvement in neurobehavioral performance, demonstrating that sleep duration should be included in assessments of sleep quality. These results have implications for the long-term use of sleep restriction in the behavioral treatment of insomnia. Clinical Trial Registration: Impact of Chronic Circadian Disruption vs. Chronic Sleep Restriction on Metabolism (https://clinicaltrials.gov/ct2/show/; #NCT02171273).

Behavioral and Molecular Consequences of Chronic Sleep Restriction During Development in Fragile X Mice.

Sleep is critical for brain development and synaptic plasticity. In male wild-type mice, chronic sleep restriction during development results in long-lasting impairments in behavior including hypoactivity, decreased sociability, and increased repetitive behavior. Disordered sleep is characteristic of many neurodevelopmental disorders. Moreover, the severity of behavioral symptoms is correlated with the degree of disordered sleep. We hypothesized that chronic developmental sleep restriction in a mouse model of fragile X syndrome (FXS) would exacerbate behavioral phenotypes. To test our hypothesis, we sleep-restricted Fmr1 knockout (KO) mice for 3 h per day from P5 to P52 and subjected mice to behavioral tests beginning on P42. Contrary to our expectations, sleep restriction improved the hyperactivity and lack of preference for social novelty phenotypes in Fmr1 KO mice but had no measurable effect on repetitive activity. Sleep restriction also resulted in changes in regional distribution of myelin basic protein, suggesting effects on myelination. These findings have implications for the role of disrupted sleep in the severity of symptoms in FXS.

[Modeling of chronic sleep restriction for translational studies]. / Sozdanie modeli khronicheskogo nedosypaniya dlya translyatsionnykh issledovanii.

OBJECTIVE: To develop of a chronic sleep restriction model in rats by repeated sleep deprivation using an orbital shaker and to determine whether this model leads to disturbances in sleep homeostatic mechanisms. MATERIAL AND METHODS: Male Wistar rats (7-8 months old) underwent sleep restriction for five consecutive days: 3 h of sleep deprivation and 1 h of sleep opportunity repeating throughout each day. Polysomnograms were recorded telemetrically throughout the day before sleep restriction (baseline), on the 1st, 3rd, 5th day of sleep restriction and 2 days after the end of sleep restriction (recovery period). RESULTS: During the period of sleep restriction, the total amount of slow-wave sleep (SWS) and rapid eye movement (REM) sleep decreased by 61% and 55%, respectively, compared to baseline. On the first day of recovery, amount of SWS increased mainly in the dark (active) phase of the day, while REM sleep increased in both light and dark phases; there was no marked rebound of daily SWS amount, while REM sleep increased by 30% from baseline. On the first day of recovery, an elevation of EEG beta and sigma power in sleep states was observed mainly in the light phase of the day. The loss of deep SWS throughout the sleep restriction period increased from 50% on 1st day to 75% on 5th day. The level of deep SWS remained below the baseline by 15-20% on the two subsequent days of recovery. The findings suggest that homeostatic mechanisms of SWS are persistently impaired after 5-day chronic sleep restriction. Besides, a decline of wakefulness accompanied by an increase of SWS in the active phase of the recovery period indicates a disruption in circadian rhythm. CONCLUSION: The proposed model leads to the disruption of sleep homeostatic mechanisms, which, in turn, impede compensation of SWS loss caused by chronic insufficient sleep.

Chronic Sleep Restriction While Minimizing Circadian Disruption Does Not Adversely Affect Glucose Tolerance.

Insufficient sleep, which has been shown to adversely affect metabolism, is generally associated with prolonged exposure to artificial light at night, a known circadian disruptor. There is growing evidence suggesting that circadian disruption adversely affects metabolism, yet few studies have attempted to evaluate the adverse metabolic effects of insufficient sleep while controlling for circadian disruption. We assessed postprandial glucose and insulin responses to a standard breakfast meal in healthy adults (n = 9) who underwent 3 weeks of chronic sleep restriction (CSR) in a 37-day inpatient study while minimizing circadian disruption by maintaining the same duration of light exposure each study day. We compared these results to findings from an earlier inpatient study which used a forced desynchrony (FD) protocol to assess the influence of 3 weeks of CSR combined with recurrent circadian disruption (RCD) on glycemic control in healthy adults (n = 21). CSR combined with RCD resulted in significantly elevated postprandial plasma glucose levels (p < 0.0001), while CSR with minimized circadian disruption had no adverse glycemic effects after 3 weeks of exposure (EXP). These results suggest that one mechanism by which sleep restriction impacts metabolism may be via concurrent circadian disruption.

Residual, differential neurobehavioral deficits linger after multiple recovery nights following chronic sleep restriction or acute total sleep deprivation.

STUDY OBJECTIVES: The amount of recovery sleep needed to fully restore well-established neurobehavioral deficits from sleep loss remains unknown, as does whether the recovery pattern differs across measures after total sleep deprivation (TSD) and chronic sleep restriction (SR). METHODS: In total, 83 adults received two baseline nights (10-12-hour time in bed [TIB]) followed by five 4-hour TIB SR nights or 36-hour TSD and four recovery nights (R1-R4; 12-hour TIB). Neurobehavioral tests were completed every 2 hours during wakefulness and a Maintenance of Wakefulness Test measured physiological sleepiness. Polysomnography was collected on B2, R1, and R4 nights. RESULTS: TSD and SR produced significant deficits in cognitive performance, increases in self-reported sleepiness and fatigue, decreases in vigor, and increases in physiological sleepiness. Neurobehavioral recovery from SR occurred after R1 and was maintained for all measures except Psychomotor Vigilance Test (PVT) lapses and response speed, which failed to completely recover. Neurobehavioral recovery from TSD occurred after R1 and was maintained for all cognitive and self-reported measures, except for vigor. After TSD and SR, R1 recovery sleep was longer and of higher efficiency and better quality than R4 recovery sleep. CONCLUSIONS: PVT impairments from SR failed to reverse completely; by contrast, vigor did not recover after TSD; all other deficits were reversed after sleep loss. These results suggest that TSD and SR induce sustained, differential biological, physiological, and/or neural changes, which remarkably are not reversed with chronic, long-duration recovery sleep. Our findings have critical implications for the population at large and for military and health professionals.

Effects of six weeks of chronic sleep restriction with weekend recovery on cognitive performance and wellbeing in high-performing adults.

Chronic sleep loss is associated with escalating declines in vigilant attention across days of sleep restriction. However, studies exceeding 2 weeks of chronic sleep loss are scarce, and the cognitive performance outcomes assessed are limited. We assessed the effects of 6 weeks of chronic sleep restriction on a range of cognitive domains in 15 high-performing individuals (38.5 ± 8.2 years, 6 women) confined to small space in groups of 4. Sleep opportunities were limited to 5 h on weekdays and 8 h on weekends. Individual sleep-wake patterns were recorded with actigraphy. Neurobehavioral performance was assessed in evenings with Cognition, a computerized battery of ten tests assessing a range of cognitive domains. There were some small to moderate effects of increasing sleep debt relative to pre-mission baseline, with decreases in accuracy across cognitive domains (standardized ß = -0.121, p = 0.001), specifically on tests of spatial orientation (ß = -0.289, p = 0.011) and vigilant attention (ß = -0.688, p < 0.001), which were not restored by two nights of weekend recovery sleep. Cognitive and subjective decrements occurred despite occasional daytime napping in breach of study protocol, evening testing around the circadian peak, and access to caffeine before 14:00. Sensorimotor speed, spatial learning and memory, working memory, abstraction and mental flexibility, emotion identification, abstract reasoning, cognitive throughput, and risk decision making were not significantly affected by sleep debt. Taken together with modest lower subjective ratings of happiness and healthiness, these findings underline the importance of sufficient sleep, on both an acute and chronic basis, for performance in selected cognitive domains and subjective wellbeing in operationally relevant environments.

The spleen mediates chronic sleep restriction-mediated enhancement of LPS-induced neuroinflammation, cognitive deficits, and anxiety-like behavior.

Chronic sleep restriction promotes neuroinflammation and cognitive deficits in neurodegenerative and neurobehavioral diseases. The spleens of mice exposed to chronic and repeated psychological stress serve as a reservoir of inflammatory myeloid cells that are released into the blood and brain following secondary acute stress. Here, we tested whether chronic and repeated short-term sleep restriction (CRSR) would exacerbate lipopolysaccharide (LPS)-induced neuroinflammation, cognitive deficits, and anxiety-like behavior in a spleen-dependent manner. LPS was administered to aged mice 14 days after exposure to CRSR consisting of three cycles of 7 days of sleep restriction with 7-day intervals in between. CRSR increased plasma proinflammatory cytokine levels, blood-brain barrier permeability, hippocampal proinflammatory cytokine levels, and transition of microglia to the M1 phenotype 24 h after LPS treatment. This in turn led to cognitive deficits and anxiety-like behavior. Interestingly, removal of the spleen 14 days prior to CRSR abrogated the enhancement of LPS-induced increases in systemic inflammation, neuroinflammation, cognitive deficits, and anxiety-like behavior. These data indicate that the spleen was essential for CRSR-induced exacerbation of LPS-induced brain damage.

Transcriptional alterations of genes related to fertility decline in male rats induced by chronic sleep restriction.

The adverse effects of sleep disorders on male fertility are of increased concern. In this study, a rat model of chronic sleep restriction (CSR) was established using the modified multiplatform method. The effects of CSR on the fertility of male rats were evaluated first based on sexual behavior. Serum hormones, including testosterone (T), prolactin (PRL), luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and sperm parameters (concentration, viability, motility, deformation rate) were measured, and testicular histology was analysed by hematoxylin and eosin staining. The transcriptional differences between CSR rats and control rats were detected by RNA sequencing (RNA-Seq), and DNA methylation was then detected by bisulfite sequencing. After the differentialy expressed genes of CSR rats were sequenced and screened, representative up- and down-regulated genes were randomly sampled to verify the sequencing results by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Finally, functional annotations were completed, including gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomic (KEGG) pathway analyses. The results showed that the sexual behavior of CSR rats did not change when compared with control group rats. The sperm concentration, viability and motility of the CSR rats decreased significantly, while the sperm malformation rate increased significantly. In the KEGG pathway analysis database, some specific differentially expressed genes were screened, which are involved in metabolic pathways, inflammation-related pathways, the renin-angiotensin system, as well as others. However, the aforesaid differentially expressed genes in the testes were not related to their DNA methylation status. CSR could significantly reduce the fertility of male rats, and one of its mechanisms occurs by altering gene expression in the testes, which is not related to their  state of  DNA methylation. The results of this study suggest that CSR could cause male infertility by significantly altering the testicular transcriptome.Abbreviations: CSR: chronic sleep restriction; SD: sleep deprivation; RNA-Seq: RNA sequencing; NGS: next generation sequencing; qRT-PCR: real-time quantitative reverse transcription polymerase chain reaction; KEGG: Kyoto encyclopedia of genes and genomic; NO: nitric oxide; INOS: Inducible nitric oxide synthase; Il6: interleukin-6; Tnf: tumour necrosis factor alpha; Hsd11b1: hydroxysteroid 11-beta dehydrogenase 1; Dnmt3a: DNA methyltransferase 3Ax; PSD: paradoxic sleep deprivation; DNMTs: DNA methyltransferases family; REM: rapid eye movement sleep; PGD: preimplantation genetic diagnosis; PGS: preimplantation genetic screening; ECS: expanded carrier screening; T: testosterone; FSH: follicle stimulating hormone; LH: luteinizing hormone; PRL: prolactin; BC group: Blank Control group; MC group: Model Control group; Hist1h2ba: histone cluster 1 H2ba; Lgr4: leucine-rich repeat-containing G protein-coupled receptor 4; Atrn: attractin ; Ogg1: 8-oxoguanine DNA glycosylase; SNVs: single nucleotide variants ; HPG axis: hypothalamic-pituitary-adrenal axis; Star protein: steroid acute regulatory protein; Dmac2l: distal membrane arm assembly complex 2 like; Esr1: estrogen receptor 1; MAPK pathways: mitogen-activated protein kinase pathways; Sos2: SOS Ras/Rho guanine nucleotide exchange factor 2; Jak2: Janus kinase 2; Pik3cb: phosphatidylinositol-4,5-bisphosphate 3-kinase, and catalytic subunit beta; Kras: KRAS proto-oncogene and GTPase; RRBS: reduced representation bisulfite sequencing; DEGs: differently expressed genes; SPF: Specific Pathogen Free; HE: hematoxylin & eosin; DMR: differentially methylated region; GO Analysis: Gene Ontology analysis; SINE: short interspersed nuclear elements; LINE: long interspersed nuclear elements; LTR: long terminal repeats.

Activation of Inflammation is Associated with Amyloid-ß Accumulation Induced by Chronic Sleep Restriction in Rats.

Alzheimer's disease (AD) is the most common age-associated neurodegenerative disease featured by progressive learning and memory deficit, and Aß was identified as playing a key role in the process of AD and was theorized to be caused by the imbalance of production and clearance. Increasing evidence suggested an association between sleep deprivation and AD. Our recent study found that chronic sleep restriction (CSR) caused cognitive impairment and Aß accumulation in rats, but the underlining mechanism was unclear. In the present study, we investigated the effects of inflammation on Aß accumulation induced by CSR. We found that CSR significantly increased the expression of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and nitric oxide (NO) in brain, and the inflammatory factors levels were positively correlated with Aß42 deposition. Additionally, the inflammatory factors were correlated with BACE1, LRP-1, and RAGE levels in both the hippocampus and the prefrontal cortex. Furthermore, the plasma levels of IL-1ß, TNF-α, and NO were elevated after CSR, and the concentration of plasma inflammatory mediators were correlated with plasma levels of sLRP1 and sRAGE. These results suggested that the inflammation in brain and plasma might be involved in the CSR-induced Aß accumulation.

Chronic sleep restriction increases soluble hippocampal Aß-42 and impairs cognitive performance.

Currently, over 44 million people worldwide suffer from Alzheimer's disease (AD). A common feature of AD is disrupted sleep. Sleep is essential for many psychological and physiological functions, though 35.3% of adults report getting less than 7 hours per night. The present research examined whether chronic sleep restriction would elevate hippocampal amyloid-beta1-42 expression or alter cognitive ability in adult C57BL/6 mice. Chronic sleep restriction was associated with cognitive impairment and increased hippocampal amyloid-beta. Thus, chronic sleep loss may have a detrimental effect upon cognitive function, in part, via increasing amyloid-beta levels in the hippocampus, even in non-genetically modified mice.

Sinoatrial node remodels in chronic sleep-restricted rats.

Chronic Sleep Restriction (CSR) is known as a risk factor for cardiovascular diseases. However, the structural changes of Sinoatrial (SA) node cells have received less attention. This study aimed to evaluate the effects of CSR on SA node in an animal model using stereological methods. Adult male Sprague-Dawley rats were randomly divided into CSR, grid-floor, and control groups. The CSR procedure was designed such a way that the animals had a full cycle of sleep (6 hours) per day, while they were unable to have a Rapid Eye Movement (REM) sleep during the remaining 18 hours. This was induced by a multiplatform box containing water. The grid-floor animals were placed in the same multiplatform box with a grid-floor covering to prevent falling in water. After 21 days, the right atria were dissected out. Then, the location of the SA node was determined and evaluated by stereological techniques. The total volume of the SA node, the total volume of the main node cells, the volume of the connective tissue, and mean volume of the node cells were respectively enlarged by 60%, 47%, 68%, and 51% in the CSR animals compared to the grid-floor rats (p < 0.05). However, no significant changes were detected in these parameters in the control and grid-floor animals. The population of the main node cells remained constant in all animal groups. In addition, the three-dimensional reconstruction of the SA node in the CSR group showed a hypertrophied appearance. In conclusion, CSR induced hypertrophic changes in the rats' SA node structures without alteration in the number of main node cells.