SLEEP AND CYTOKINES

Dietary inflammatory index (DII) and sleep quality, duration, and timing: A systematic review

Sleep has strong inflammatory underpinnings and diet is one of the primary determinants of systemic inflammation. A systematic literature review was conducted to synthesize current research associating dietary inflammatory potential, as measured by the dietary inflammatory index (DII®) or the energy-adjusted DII (E-DII™) and sleep quality and duration. The National Library of Medicine (Medline), Web of Science, and PsycInfo databases were searched through March 2023. Studies must have used the DII/E-DII as the independent variable and sleep outcomes as dependent variables. Study characteristics, based on STROBE guidelines, were scored based on the presence of the recommendation. Out of the initial 14 studies identified, a total of 12 studies were included for data synthesis. In all 12 studies, more anti-inflammatory diets (i.e., low DII/E-DII scores) were associated with better sleep in at least one sleep domain (most often sleep efficiency and wake-after-sleep-onset). Among those studies with more rigorous diet and sleep measurements, such as dietary recalls and actigraphy, associations between DII/E-DII and sleep outcomes were stronger and more consistent compared to studies using primarily subjective assessments. More rigorous measurement of diet and sleep, especially those relating to sleep stage structure, should be considered in future studies with prospective designs.

Does EGFR Signaling Mediate Orexin System Activity in Sleep Initiation?

Sleep-wake cycle disorders are an important symptom of many neurological diseases, including Parkinson's disease, Alzheimer's disease, and multiple sclerosis. Circadian rhythms and sleep-wake cycles play a key role in maintaining the health of organisms. To date, these processes are still poorly understood and, therefore, need more detailed elucidation. The sleep process has been extensively studied in vertebrates, such as mammals and, to a lesser extent, in invertebrates. A complex, multi-step interaction of homeostatic processes and neurotransmitters provides the sleep-wake cycle. Many other regulatory molecules are also involved in the cycle regulation, but their functions remain largely unclear. One of these signaling systems is epidermal growth factor receptor (EGFR), which regulates the activity of neurons in the modulation of the sleep-wake cycle in vertebrates. We have evaluated the possible role of the EGFR signaling pathway in the molecular regulation of sleep. Understanding the molecular mechanisms that underlie sleep-wake regulation will provide critical insight into the fundamental regulatory functions of the brain. New findings of sleep-regulatory pathways may provide new drug targets and approaches for the treatment of sleep-related diseases.

Understanding neuron-glia crosstalk and biological clocks in insomnia

According to the World Health Organization, about one-third of the population experiences insomnia symptoms, and about 10-15% suffer from chronic insomnia, the most common sleep disorder. Sleeping difficulties associated with insomnia are often linked to chronic sleep deprivation, which has a negative health impact partly due to disruption in the internal synchronisation of biological clocks. These are regulated by clock genes and modulate most biological processes. Most studies addressing circadian rhythm regulation have focused on the role of neurons, yet glial cells also impact circadian rhythms and sleep regulation. Chronic insomnia and sleep loss have been associated with glial cell activation, exacerbated neuroinflammation, oxidative stress, altered neuronal metabolism and synaptic plasticity, accelerated age-related processes and decreased lifespan. It is, therefore, essential to highlight the importance of glia-neuron interplay on sleep/circadian regulation and overall healthy brain function. Hence, in this review, we aim to address the main neurobiological mechanisms involved in neuron-glia crosstalk, with an emphasis on microglia and astrocytes, in both healthy sleep, chronic sleep deprivation and chronic insomnia.

Dietary Inflammatory Index and sleep quality and duration among pregnant women with overweight or obesity

STUDY OBJECTIVES

Sleep disturbances, which can worsen during pregnancy, have been linked to inflammatory processes. This study tested the hypothesis that more pro-inflammatory diets during pregnancy are associated with a decrease in sleep quality and shorter sleep duration.

METHODS

The Health in Pregnancy and Postpartum study promoted a healthy lifestyle in pregnant women with pre-pregnancy overweight or obesity (n = 207). Data from <16 weeks and 32 weeks gestation were used. Sleep was measured using BodyMedia's SenseWear® armband. Diet was assessed using two 24-hr dietary recalls. Energy-density Dietary Inflammatory Index (E-DIITM) scores were calculated from micro and macronutrients. Linear mixed-effects models estimated the impact of the E-DII score on sleep parameters.

RESULTS

Women with more pro-inflammatory diets, compared to those with more anti-inflammatory diets, were more likely to be nulliparous (51% vs. 25%, p = 0.03), frequent consumers of fast food (29% vs. 10% consuming on 4-6 days during the previous week, p = 0.01), ever-smokers (21% vs. 6%, p = 0.02), and younger (mean age 29.2 vs. 31.3 years, p = 0.02). For every one-unit increase (i.e., more pro-inflammatory) in the E-DII score, sleep latency increased by 0.69 min (p < 0.01). Among European Americans only, every one-unit higher E-DII was associated with a 2.92-min longer wake-after-sleep-onset (p = 0.02).

CONCLUSION

An E-DII score that is 5 points lower (i.e., more anti-inflammatory) would equate to about 105 min of additional sleep per week among European American women. Anti-inflammatory diets may help to counteract detriments in sleep during pregnancy, especially among European American women. Additional work is needed among African American women.

CLINICAL TRIALS IDENTIFIER

Name: Promoting Health in Pregnancy and Postpartum (HIPP); URL: https://clinicaltrials.gov/ct2/show/NCT02260518; Registration Identifier: NCT02260518.

The Molecular Relationship between Stress and Insomnia

The bi-directional relationship between sleep and stress has been actively researched as sleep disturbances and stress have become increasingly common in society. Interestingly, the brain and underlying neural circuits important for sleep regulation may respond uniquely to stress that leads to post-traumatic stress disorder (PTSD) and stress that does not. In stress that does not lead to PTSD, the hypothalamic-pituitary-adrenal axis (HPA) pathway is activated normally that results in sympathetic nervous system activation that allows the brain and body to return to baseline functioning. However, exposure to stress that leads to PTSD, causes enhanced negative feedback of this same pathway and results in long-term physiological and psychological changes. In this review, how stress regulates glucocorticoid signaling pathways in brain glial cells called astrocytes, and then mediates stress-induced insomnia are examined. Astrocytes are critical sleep regulatory cells and their connections to sleep and stress due to disturbed glucocorticoid signaling provide a novel mechanism to explain how stress leads to insomnia. This review will examine the interactions of stress neurobiology, astrocytes, sleep, and glucocorticoid signaling pathways and will examine the how stress that leads to PTSD and stress that does not impacts sleep-regulatory processes.

Drug-Induced Insomnia and Excessive Sleepiness

Undesirable side effects of insomnia and/or sleepiness may occur with many prescribed drugs, psychotropics as well as non-psychotropics. These central nervous system effects can be explained by the interactions of the drug with any of the numerous neurotransmitters and receptors that are involved in sleep and wakefulness. Also a close - sometimes bidirectional - relationship between disease and (disturbed) sleep/wakefulness is often present e.g. in chronic pain; drug effects may lead this vicious circle in both ways. Besides the importance for health and quality of life, effects on sleep or waking function can be a potential source of non-compliance.

Microglia Are Necessary to Regulate Sleep after an Immune Challenge

Microglia play a critical role in the neuroimmune response, but little is known about the role of microglia in sleep following an inflammatory trigger. Nevertheless, decades of research have been predicated on the assumption that an inflammatory trigger increases sleep through microglial activation. We hypothesized that mice (n = 30) with depleted microglia using PLX5622 (PLX) would sleep less following the administration of lipopolysaccharide (LPS) to induce inflammation. Brains were collected and microglial morphology was assessed using quantitative skeletal analyses and physiological parameters were recorded using non-invasive piezoelectric cages. Mice fed PLX diet had a transient increase in sleep that dissipated by week 2. Subsequently, following a first LPS injection (0.4 mg/kg), mice with depleted microglia slept more than mice on the control diet. All mice were returned to normal rodent chow to repopulate microglia in the PLX group (10 days). Nominal differences in sleep existed during the microglia repopulation period. However, following a second LPS injection, mice with repopulated microglia slept similarly to control mice during the dark period but with longer bouts during the light period. Comparing sleep after the first LPS injection to sleep after the second LPS injection, controls exhibited temporal changes in sleep patterns but no change in cumulative minutes slept, whereas cumulative sleep in mice with repopulated microglia decreased during the dark period across all days. Repopulated microglia had a reactive morphology. We conclude that microglia are necessary to regulate sleep after an immune challenge.

The evolutionarily conserved miRNA-137 targets the neuropeptide hypocretin/orexin and modulates the wake to sleep ratio

The hypocretin (Hcrt, also known as orexin) neuropeptides regulate sleep and wake stability, and disturbances of Hcrt can lead to sleep disorders. MicroRNAs (miRNAs) are short noncoding RNAs that fine-tune protein expression levels, and miRNA-based therapeutics are emerging. We report a functional interaction between miRNA (miR-137) and Hcrt. We demonstrate that intracellular miR-137 levels in Hcrt neurons regulate Hcrt expression with downstream effects on wakefulness. Specifically, lowering of miR-137 levels increased wakefulness in mice. We further show that the miR-137:Hcrt interaction is conserved across mice and humans, that miR-137 also regulates sleep–wake balance in zebrafish, and that the MIR137 locus is genetically associated with sleep duration in humans. Together, our findings reveal an evolutionarily conserved sleep–wake regulatory role of miR-137.

Hypocretin (Hcrt), also known as orexin, neuropeptide signaling stabilizes sleep and wakefulness in all vertebrates. A lack of Hcrt causes the sleep disorder narcolepsy, and increased Hcrt signaling has been speculated to cause insomnia, but while the signaling pathways of Hcrt are relatively well-described, the intracellular mechanisms that regulate its expression remain unclear. Here, we tested the role of microRNAs (miRNAs) in regulating Hcrt expression. We found that miR-137, miR-637, and miR-654-5p target the human HCRT gene. miR-137 is evolutionarily conserved and also targets mouse Hcrt as does miR-665. Inhibition of miR-137 specifically in Hcrt neurons resulted in Hcrt upregulation, longer episodes of wakefulness, and significantly longer wake bouts in the first 4 h of the active phase. IL-13 stimulation upregulated endogenous miR-137, while Hcrt mRNA decreased both in vitro and in vivo. Furthermore, knockdown of miR-137 in zebrafish substantially increased wakefulness. Finally, we show that in humans, the MIR137 locus is genetically associated with sleep duration. In conclusion, these results show that an evolutionarily conserved miR-137:Hcrt interaction is involved in sleep–wake regulation.

Neuroinflammation, Sleep, and Circadian Rhythms

Molecules involved in innate immunity affect sleep and circadian oscillators and vice versa. Sleep-inducing inflammatory molecules are activated by increased waking activity and pathogens. Pathologies that alter inflammatory molecules, such as traumatic brain injury, cancer, cardiovascular disease, and stroke often are associated with disturbed sleep and electroencephalogram power spectra. Moreover, sleep disorders, such as insomnia and sleep disordered breathing, are associated with increased dysregulation of inflammatory processes. Inflammatory molecules in both the central nervous system and periphery can alter sleep. Inflammation can also modulate cerebral vascular hemodynamics which is associated with alterations in electroencephalogram power spectra. However, further research is needed to determine the interactions of sleep regulatory inflammatory molecules and circadian clocks. The purpose of this review is to: 1) describe the role of the inflammatory cytokines interleukin-1 beta and tumor necrosis factor-alpha and nucleotide-binding domain and leucine-rich repeat protein-3 inflammasomes in sleep regulation, 2) to discuss the relationship between the vagus nerve in translating inflammatory signals between the periphery and central nervous system to alter sleep, and 3) to present information about the relationship between cerebral vascular hemodynamics and the electroencephalogram during sleep.

Sleep Disturbance and Alzheimer's Disease: The Glial Connection

Poor quality and quantity of sleep are very common in elderly people throughout the world. Growing evidence has suggested that sleep disturbances could accelerate the process of neurodegeneration. Recent reports have shown a positive correlation between sleep deprivation and amyloid-β (Aβ)/tau aggregation in the brain of Alzheimer's patients. Glial cells have long been implicated in the progression of Alzheimer's disease (AD) and recent findings have also suggested their role in regulating sleep homeostasis. However, how glial cells control the sleep-wake balance and exactly how disturbed sleep may act as a trigger for Alzheimer's or other neurological disorders have recently gotten attention. In an attempt to connect the dots, the present review has highlighted the role of glia-derived sleep regulatory molecules in AD pathogenesis. Role of glia in sleep disturbance and Alzheimer's progression.

Assessment of Stress Salivary Markers, Perceived Stress, and Shift Work in a Cohort of Fishermen: A Preliminary Work

Due to work-related stress, today, work itself represents a daily challenge that must be faced in many occupations. While, in the past, the scientific community has focused on the helping professions, since, an increasing number of professions have since been investigated. Therefore, different approaches exist in order to assess this disorder, representing a scientific field wherein biological and psychological dimensions both need to be evaluated. In this paper, we consider three biological salivary markers: interleukin 1 beta (IL-1β), cortisol, and melatonin. The choice derives from recent contributions to the literature in which the interplay between these markers has been verified. Briefly, such interplay could explain how the central nervous, endocrine, and immune systems communicate with each other, supporting a holistic concept of person. In 30 marine fishermen from the Apulia region of Italy, perceived stress was measured using the Professional Stress Scale (PSS) and sleep disturbances were assessed through the Pittsburgh Sleep Quality Index (PSQI). Salivary markers were collected at 8:00 a.m. and 2:00 p.m. Those subjects reporting sleep disturbance and having altered scores in two PSS subclasses, home-work conflict and self-esteem, presented inverted salivary melatonin and cortisol nictemeral rhythms (with regard to melatonin levels at 8:00 a.m., those workers reporting values higher than the median showed 64.1% versus 48.6% home-work conflict with respect to cortisol levels, subjects having an inverted circadian rhythm showed 69.9% versus 52.5% home-work conflict, and these values resulted 47.7% versus 25.3% when the self-esteem was considered). As regards melatonin, PSQI score is statistically different in the two groups of subjects as identified by median melatonin at 8:00 a.m.; specifically, the subjects who had mean values higher than the median shared higher PSQI scores (10.8 versus 9.8). The same subjects reported more frequent home-work conflict and more sleep disorders. We found a negative correlation between IL-1β at 8:00 a.m. and Cortdiff (the difference between cortisol at 8:00 a.m.-cortisol at 2:00 p.m.), and that high IL-1β at 8:00 a.m. was associated with low Cortdiff. Based on our results we would like to propose this approach in health surveillance, in order to prevent mental and/or physical disorders, however our study is surely preliminary. The interesting perspectives and hypotheses cited in this paper, in which the roles of IL-1β and norepinephrine appear central and important, could remain hypothetical if not supported by more robust observation in order to produce, truly, new knowledge. In the future we will deepen this study with a larger sample, and if these results will be confirmed, this approach could allow preventing, not only mental and physical disorders, but also immuno-mediated diseases, and, perhaps, cancer.

Developing a Novel Measurement of Sleep in Rheumatoid Arthritis: Study Proposal for Approach and Considerations

The development of novel digital endpoints (NDEs) using digital health technologies (DHTs) may provide opportunities to transform drug development. It requires a multidisciplinary, multi-study approach with strategic planning and a regulatory-guided pathway to achieve regulatory and clinical acceptance. Many NDEs have been explored; however, success has been limited. To advance industry use of NDEs to support drug development, we outline a theoretical, methodological study as a use-case proposal to describe the process and considerations when developing and obtaining regulatory acceptance for an NDE to assess sleep in patients with rheumatoid arthritis (RA). RA patients often suffer joint pain, fatigue, and sleep disturbances (SDs). Although many researchers have investigated the mobility of joint functions using wearable technologies, the research of SD in RA has been limited due to the availability of suitable technologies. We proposed measuring the improvement of sleep as the novel endpoint for an anti-TNF therapy and described the meaningfulness of the measure, considerations of tool selection, and the design of clinical validation. The recommendations from the FDA patient-focused drug development guidance, the Clinical Trials Transformation Initiative (CTTI) pathway for developing novel endpoints from DHTs, and the V3 framework developed by the Digital Medicine Society (DiMe) have been incorporated in the proposal. Regulatory strategy and engagement pathways are also discussed.

Why It Is Important to Consider the Effects of Analgesics on Sleep: A Critical Review

We review the known physiological mechanisms underpinning all of pain processing, sleep regulation, and pharmacology of analgesics prescribed for chronic pain. In particular, we describe how commonly prescribed analgesics act in sleep-wake neural pathways, with potential unintended impact on sleep and/or wake function. Sleep disruption, whether pain- or drug-induced, negatively impacts quality of life, mental and physical health. In the context of chronic pain, poor sleep quality heightens pain sensitivity and may affect analgesic function, potentially resulting in further analgesic need. Clinicians already have to consider factors including efficacy, abuse potential, and likely side effects when making analgesic prescribing choices. We propose that analgesic-related sleep disruption should also be considered. The neurochemical mechanisms underlying the reciprocal relationship between pain and sleep are poorly understood, and studies investigating sleep in those with specific chronic pain conditions (including those with comorbidities) are lacking. We emphasize the importance of further work to clarify the effects (intended and unintended) of each analgesic class to inform personalized treatment decisions in patients with chronic pain. © 2021 American Physiological Society. Compr Physiol 11:1-31, 2021.

Experimental diffuse brain injury and a model of Alzheimer's disease exhibit disease-specific changes in sleep and incongruous peripheral inflammation

Elderly populations (≥65 years old) have the highest risk of developing Alzheimer's disease (AD) and/or obtaining a traumatic brain injury (TBI). Using translational mouse models, we investigated sleep disturbances and inflammation associated with normal aging, TBI and aging, and AD. We hypothesized that aging results in marked changes in sleep compared with adult mice, and that TBI and aging would result in sleep and inflammation levels similar to AD mice. We used female 16-month-old wild-type (WT Aged) and 3xTg-AD mice, as well as a 2-month-old reference group (WT Adult), to evaluate sleep changes. WT Aged mice received diffuse TBI by midline fluid percussion, and blood was collected from both WT Aged (pre- and post-TBI) and 3xTg-AD mice to evaluate inflammation. Cognitive behavior was tested, and tissue was collected for histology. Bayesian generalized additive and mixed-effects models were used for analyses. Both normal aging and AD led to increases in sleep compared with adult mice. WT Aged mice with TBI slept substantially more, with fragmented shorter bouts, than they did pre-TBI and compared with AD mice. However, differences between WT Aged and 3xTg-AD mice in immune cell populations and plasma cytokine levels were incongruous, cognitive deficits were similar, and cumulative sleep was not predictive of inflammation or behavior for either group. Our results suggest that in similarly aged individuals, TBI immediately induces more profound sleep alterations than in AD, although both diseases likely include cognitive impairments. Unique pathological sleep pathways may exist in elderly individuals who incur TBI compared with similarly aged individuals who have AD, which may warrant disease-specific treatments in clinical settings.

Disease characteristics and neuropathological changes associated with cognitive dysfunction in obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common sleep-disordered breathing disease that often leads to many comorbidities (e.g., cognitive dysfunction), which adversely affect the quality of life for patients with OSA. Thus far, the underlying mechanisms of this dysfunction remain unclear. Many studies have focused on OSA-related characteristics, including intermittent hypoxemia and sleep fragmentation. There is increasing emphasis on neuroimaging studies to explore underlying relationships between neuropathological changes and cognitive dysfunction. This article reviews recent research progress concerning cognitive dysfunction associated with OSA to reveal potential mechanisms that contribute to this dysfunction.

Influence of Skin Subjective Symptoms on Sleep Quality in Patients with Cutaneous Disorders: A Study of 2871 Subjects

Introduction

Previous studies showed more sleep disturbance (SD) in patients with cutaneous disorders (CD). During CD, unpleasant subjective symptoms [USS], such as itch, pain and others (tingling, burning, or tightness) have a negative influence on sleep quality. This study aims to evaluate the prevalence of SD in CD patients and to identify the influence of itch, pain and other unpleasant sensations on SD.

Materials and Methods

An international, anonymized real-life survey was conducted with individuals [18−75 years], with physician-confirmed CD, or without CD. The 25 items covered sociodemographic characteristics, feeling of overall sleep quality and skin unpleasant sensations. Severity of SD and unpleasant sensations were assessed using a 10-cm Visual Analogue Scale (VAS).

Results

From 3834 analyzed questionnaires, 2871 (67.3%) were in the CD group and 863 (32.7%) in the control group. Patients with CD had significantly more SD (71.2% vs 32.7% in the control group, p<0.0001). CD patients without any reported unpleasant sensation were at higher risk for SD than control subjects (OR 1,362 [95% CI 1.975–2.405] p=0.0013). SS were highly associated with SD (OR 1.641 [95% CI 1.393–1.933] p<0.0001). Pruritus, pain and intermediate sensations were significant predictors of SD, with odds ratios of 1.670, 1.625 and 1.326, respectively. VAS sleep scores were strongly associated with pruritus (r: 0.25, p<0.0001) and pain (r: 0.25 p<0.0001) severity ratings.

Discussion

SD is a common problem for patients with CD. Patients with subjective symptoms suffer more from SD, suggesting that they are aggravating factors, but are likely not the only reason for SD in CD patients. We found that during CD, intermediate sensations also contribute to SD. Despite some limitations and the potential bias due to the study design, our results confirm for the first time on an international level the influence of subjective symptoms on sleep quality in patients with CD.

Longitudinal Changes in Sleep: Associations with Shifts in Circulating Cytokines and Emotional Distress in a Cancer Survivor Population

BACKGROUND

Sleep disturbances are associated with numerous mood disorders. Similarly, anxiety and depression are associated with modulation of the psychoneuroimmune (PNI) axis. This study hypothesized that changes in both monitored and self-reported measures of sleep would relate to changes in circulating cytokine levels in an emotionally distressed population of cervical cancer survivors.

METHODS

Biospecimens, patient-reported outcome (PRO) measures, and actigraphy were collected from cervical cancer survivors enrolled in a biobehavioral clinical trial. Longitudinal changes over a 4-month period were examined. Sleep time measured by actigraphy and PRO were analyzed for correlative changes with emotional distress and serum cytokines (n = 71).

RESULTS

Longitudinal change in the actigraph measure of sleep time was inversely associated with changes in depression and anxiety (test for linear trend, p = 0.02 and p = 0.05 respectively), as well as acute-phase response/pro-inflammatory cytokines (test for linear trend, p = 0.003, interleukin (IL)-2; 0.022, IL-1β; 0.0002, IL-6; and 0.049, tumor necrosis factor α). Conversely, changes in self-reported sleep problems were related to an increase in depression and anxiety (p = 0.001 and p = 0.01 respectively), the T helper 2 (Th2) cytokine IL-5 (p = 0.027), and the counter-regulatory cytokine IL-10 (0.016).

CONCLUSION

This study showed that an increase in sleep time or decrease in sleep problems corresponded with a reduction in self-reported emotional distress and attenuation of pro-inflammatory, Th2, and counter-regulatory cytokines. Our results support sleep measurement as a meaningful biobehavioral variable in cancer survivorship. This study also indicates that sleep investigators should be aware that choice of methodology might influence concordance with different classes of immune parameters.

Molecular links between endocrine, nervous and immune system during chronic stress

INTRODUCTION

The stress response is different in various individuals, however, the mechanisms that could explain these distinct effects are not well known and the molecular correlates have been considered one at the time. Particular harmful conditions occur if the subject, instead to cope the stressful events, succumb to them, in this case, a cascade reaction happens that through different signaling causes a specific reaction named "sickness behaviour." The aim of this article is to review the complex relations among important molecules belonging to Central nervous system (CNS), immune system (IS), and endocrine system (ES) during the chronic stress response.

METHODS

After having verified the state of art concerning the function of cortisol, norepinephrine (NE), interleukin (IL)-1β and melatonin, we describe as they work together.

RESULTS

We propose a speculative hypothesis concerning the complex interplay of these signaling molecules during chronic stress, highlighting the role of IL-1β as main biomarker of this effects, indeed, during chronic stress its increment transforms this inflammatory signal into a nervous signal (NE), in turn, this uses the ES (melatonin and cortisol) to counterbalance again IL-1β. During cortisol resistance, a vicious loop occurs that increments all mediators, unbalancing IS, ES, and CNS networks. This IL-1β increase would occur above all when the individual succumbs to stressful events, showing the Sickness Behaviour Symptoms. IL-1β might, through melatonin and vice versa, determine sleep disorders too.

CONCLUSION

The molecular links here outlined could explain how stress plays a role in etiopathogenesis of several diseases through this complex interplay.

Sleep Disturbance during Infection Compromises Tfh Differentiation and Impacts Host Immunity

Although the influence of sleep quality on the immune system is well documented, the mechanisms behind its impact on natural host immunity remain unclear. Meanwhile, it has been suggested that neuroimmune interactions play an important role in this phenomenon. To evaluate the impact of stress-induced sleep disturbance on host immunity, we used a murine model of rapid eye movement sleep deprivation (RSD) integrated with a model of malaria blood-stage infection. We demonstrate that sleep disturbance compromises the differentiation of T follicular helper cells, increasing host susceptibility to the parasite. Chemical inhibition of glucocorticoid (Glcs) synthesis showed that abnormal Glcs production compromised the transcription of Tfh-associated genes resulting in impaired germinal center formation and humoral immune response. Our data demonstrate that RSD-induced abnormal activation of the hypothalamic-pituitary-adrenal axis drives host susceptibility to infection. Understanding the impact of sleep quality in natural resistance to infection may provide insights for disease management.

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REM sleep deprivation (RSD) worsens malaria induced by Plasmodium yoelii infection

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RSD decreases germinal center formation and impairs specific antibody production

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Exacerbated glucocorticoid production impairs T lymphocyte differentiation

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The relationship between sleep and immunity is a target for malaria management

Sleep, circadian rhythm, and gut microbiota

From asthma and heart disease to diabetes and obesity, the human microbiome plays a role in the pathogenesis of each chronic health condition plaguing today's society. Recent work has shown that the gut microbiota and its metabolites exhibit diurnal rhythmicity which predominantly respond to the feeding/fasting cycle. Persistent jet lag, an obesogenic diet, and clock gene deficiency can dampen the oscillatory nature of gut bacterial composition, which can subsequently be rescued by time restricted feeding. Contrastingly, gut microbial metabolites influence central and hepatic clock gene expression and sleep duration in the host and regulate body composition through circadian transcription factors. Both sleep fragmentation and short sleep duration are associated with gut dysbiosis which may be due to activation of the HPA-axis. Metabolic disturbances associated with sleep loss may in fact be mediated through the overgrowth of specific gut bacteria. Reciprocally, the end products of bacterial species which grow in response to sleep loss are able to induce fatigue. Furthermore, probiotic supplementation has been found to improve subjective sleep quality. Sleep quality and duration may be an important target for supporting healthy gut microbiota composition, but the cyclic nature of this relationship should not be overlooked.

Evolutionarily conserved regulation of sleep by epidermal growth factor receptor signaling

The genetic bases for most human sleep disorders and for variation in human sleep quantity and quality are largely unknown. Using the zebrafish, a diurnal vertebrate, to investigate the genetic regulation of sleep, we found that epidermal growth factor receptor (EGFR) signaling is necessary and sufficient for normal sleep levels and is required for the normal homeostatic response to sleep deprivation. We observed that EGFR signaling promotes sleep via mitogen-activated protein kinase/extracellular signal-regulated kinase and RFamide neuropeptide signaling and that it regulates RFamide neuropeptide expression and neuronal activity. Consistent with these findings, analysis of a large cohort of human genetic data from participants of European ancestry revealed that common variants in genes within the EGFR signaling pathway are associated with variation in human sleep quantity and quality. These results indicate that EGFR signaling and its downstream pathways play a central and ancient role in regulating sleep and provide new therapeutic targets for sleep disorders.

Machine Learning to Understand the Immune-Inflammatory Pathways in Fibromyalgia

Fibromyalgia (FM) is a chronic syndrome characterized by widespread musculoskeletal pain, and physical and emotional symptoms. Although its pathophysiology is largely unknown, immune-inflammatory pathways may be involved. We examined serum interleukin (IL)-6, high sensitivity C-reactive protein (hs-CRP), CXCL-8, and IL-10 in 67 female FM patients and 35 healthy women while adjusting for age, body mass index (BMI), and comorbid disorders. We scored the Fibromyalgia Severity Score, Widespread Pain Index (WPI), Symptom Severity Scale (SSS), Hospital Anxiety (HADS-A), and Depression Scale and the Perceived Stress Scale (PSS-10). Clinical rating scales were significantly higher in FM patients than in controls. After adjusting for covariates, IL-6, IL-10, and CXCL-8 were lower in FM than in HC, whereas hs-CRP did not show any difference. Binary regression analyses showed that the diagnosis FM was associated with lowered IL-10, quality of sleep, aerobic activities, and increased HADS-A and comorbidities. Neural networks showed that WPI was best predicted by quality of sleep, PSS-10, HADS-A, and the cytokines, while SSS was best predicted by PSS-10, HADS-A, and IL-10. Lowered levels of cytokines are associated with FM independently from confounders. Lowered IL-6 and IL-10 signaling may play a role in the pathophysiology of FM.

Interleukin-1 receptor accessory proteins are required for normal homeostatic responses to sleep deprivation

Interleukin-1β (IL1) is a sleep regulatory substance. The IL1/IL1 type 1 receptor complex requires a receptor accessory protein (AcP) to signal. There are three isoforms of AcP. In the current experiments, mice lacking a neuron-specific isoform, called AcPb knockout (AcPb KO), or mice lacking AcP + AcPb isoforms (AcP KO) or wild-type (WT) mice were used. Spontaneous sleep and sleep responses to sleep deprivation (SD) between zeitgeber time (ZT) 20-ZT4 and ZT8-ZT16 were characterized. Furthermore, somatosensory cortical protein extracts were examined for phosphorylated (p) proto-oncogene tyrosine-protein kinase sarcoma (Src) and p38MAPK levels at ZT4 and ZT16 and after SD. Spontaneous sleep was similar in the three strains, except rapid eye movement sleep (REMS) duration between ZT12-ZT16 was greater in AcP KO than WT mice. After SD at ZT4, only WT mice had non-REMS (NREMS) rebounds. All mouse strains lacked an NREMS rebound after SD at ZT16. All strains after both SD periods had REMS rebounds. AcPb KO mice, but not AcP KO mice, had greater EEG delta wave (0.5-4 Hz) power during NREMS than WT mice. p-Src was very low at ZT16 but high at ZT4, whereas p-p38MAPK was low at ZT4 and high at ZT16. p-p38MAPK levels were not sensitive to SD. In contrast, p-Src levels were less after SD at the P = 0.08 level of significance in the strains lacking AcPb. We conclude that AcPb is required for NREMS responses to sleep loss, but not for SD-induced EEG delta wave or REMS responses.NEW & NOTEWORTHY Interleukin-1β (IL1), a well-characterized sleep regulatory substance, requires an IL1 receptor accessory protein (AcP); one of its isoforms is neuron-specific (called AcPb). We showed that in mice, AcPb is required for nonrapid eye movement sleep responses following 8 h of sleep loss ending 4 h after daybreak but did not affect rapid eye movement sleep rebound. Sleep loss reduced phosphorylation of proto-oncogene tyrosine-protein kinase sarcoma but not of the less sensitive p38MAPK, downstream IL1 signaling molecules.

Authentic tart cherry juice reduces markers of inflammation in overweight and obese subjects: a randomized, crossover pilot study

Subclinical inflammation is frequently noted in chronic diseases such as diabetes, cardiovascular disease (CVD) and obesity. Accumulating epidemiological evidence demonstrates that diets rich in vegetables and fruits, e.g., cherries, may significantly reduce the risk of chronic disease, in part, via antioxidant and anti-inflammatory activities. In this randomized, placebo-controlled crossover study, we recruited 10 at-risk participants (38.1 ± 12.5 years; 8 females, 2 males) with BMI >25.0 kg m-2 (32.2 ± 4.6 kg m-2; 5 obese, 5 overweight) to consume 240 mL (8 ounces) daily of either 100% tart cherry juice (TCJ) or an alternate placebo beverage, for 4 weeks with a 2-week intervening washout period before switching to the alternate beverage for four weeks. Fasting blood samples were collected at the beginning and end of each arm for measurement of biomarkers of inflammation. The erythrocyte sedimentation rate (ESR), an indicator of chronic inflammation, was significantly (p < 0.05) lower with TCJ than with the placebo beverage, which increased ESR by 19%. Mean baseline hsCRP, an indicator of acute inflammation, was 7.0 ± 5.2 mg L-1 and consumption of TCJ did not affect hsCRP levels. The chemokine MCP-1 and cytokine TNF-alpha were lower in participants after consuming TCJ compared to those consuming the placebo beverage. Plasma IL-6 and IL-l0 were not different between treatments. Collectively, the data suggest that authentic 100% TCJ may reduce biomarkers of inflammation often noted in chronic disease and may be a preferable dietary selection compared to artificially flavored beverages with added sugars.

Sleep and Orofacial Pain

Sleep and pain share a bidirectional relationship. Therefore, it is important for practitioners managing patients experiencing either sleep and/or pain issues to recognize and understand this complex association from a neurobiological perspective involving neuroanatomic and neurochemical processes. Accounting for the influence of pain on the various aspects of sleep and understanding its impact on various orofacial pain disorders assists in developing a prudent management approach. Screening for sleep disorders benefits practitioners in identifying these individuals. Instituting evidence-based multidisciplinary management strategies using both behavioral and pharmacologic strategies enhances the delivery of appropriate care.

Vitamin D in SLE: a role in pathogenesis and fatigue? A review of the literature

Fatigue is a common, disabling problem that is highly prevalent in patients with systemic lupus erythematous (SLE). More recently, vitamin D status has been established as a potential contributor to SLE pathogenesis and manifestations, in particular fatigue. This review summarizes the literature regarding the role of vitamin D in SLE, and provides an overview of the recent literature examining the association between vitamin D and fatigue in patients with SLE. Finally, the role of vitamin D supplementation in the treatment of SLE-related fatigue is considered.

Characterization of sleep-pattern and neuro-immune-endocrine markers at 24 hour post-injection of a single low dose of lipopolysaccharide in male Wistar rats

The long-term effect of immune system activation by a low dose of lipopolysaccharide on neuro-immune-endocrine regulation is unclear. Sleep, neurotransmitter concentrations, TNF-α, and corticosterone levels were evaluated in male Wistar rats implanted with conventional sleep recordings. In this work, we found that REM sleep was reduced in the first 4 h post-injection, without affecting the total sleep time, while adrenaline concentration was reduced in the hippocampus at 24 h post-injection of LPS. Our results demonstrated that, although the acute immune response was not evident 24 h after the injection of LPS, it was able to promote the reduction of AD in the hippocampus, which may explain in part the depressive behavior reported in rodents following LPS administration.

Effects of binge alcohol consumption on sleep and inflammation in healthy volunteers

Objective

Alcohol is a hypnotic that modifies immune function, specifically the cytokines interferon gamma (IFN-γ) and interleukin 2 (IL-2). We evaluated the association between unscheduled napping and acute alcohol-induced augmentation of IFN-γ and IL-2 expression.

Methods

In this prospective, observational pilot study, volunteers completed questionnaires on sleep quality, alcohol use, and hangover characteristics. Actigraph recordings began three nights before and continued for four nights after study initiation. Napping was recorded by actigraphy and self-reporting. A weight-based dose of 100-proof vodka was consumed, and the blood alcohol content (BAC) and phytohemagglutinin-M stimulated cytokine level were measured before and 20 minutes, 2 hours, and 5 hours after binge consumption.

Results

Ten healthy volunteers participated (mean age, 34.4 ± 2.3 years; mean body mass index, 23.9 ± 4.6 kg/m²; 60% female). The mean 20-minute BAC was 137.7 ± 40.7 mg/dL. Seven participants took an unscheduled nap. The ex vivo IFN-γ and IL-2 levels significantly increased at all time points after binge consumption in the nappers, but not in the non-nappers.

Conclusion

Augmented IFN-γ and IL-2 levels are associated with unscheduled napping after binge alcohol consumption. Further studies are needed to clarify the associations among alcohol consumption, sleep disruption, and inflammatory mediators.

Novel TNF receptor-1 inhibitors identified as potential therapeutic candidates for traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) begins with the application of mechanical force to the head or brain, which initiates systemic and cellular processes that are hallmarks of the disease. The pathological cascade of secondary injury processes, including inflammation, can exacerbate brain injury-induced morbidities and thus represents a plausible target for pharmaceutical therapies. We have pioneered research on post-traumatic sleep, identifying that injury-induced sleep lasting for 6 h in brain-injured mice coincides with increased cortical levels of inflammatory cytokines, including tumor necrosis factor (TNF). Here, we apply post-traumatic sleep as a physiological bio-indicator of inflammation. We hypothesized the efficacy of novel TNF receptor (TNF-R) inhibitors could be screened using post-traumatic sleep and that these novel compounds would improve functional recovery following diffuse TBI in the mouse.

METHODS

Three inhibitors of TNF-R activation were synthesized based on the structure of previously reported TNF CIAM inhibitor F002, which lodges into a defined TNFR1 cavity at the TNF-binding interface, and screened for in vitro efficacy of TNF pathway inhibition (IκB phosphorylation). Compounds were screened for in vivo efficacy in modulating post-traumatic sleep. Compounds were then tested for efficacy in improving functional recovery and verification of cellular mechanism.

RESULTS

Brain-injured mice treated with Compound 7 (C7) or SGT11 slept significantly less than those treated with vehicle, suggesting a therapeutic potential to target neuroinflammation. SGT11 restored cognitive, sensorimotor, and neurological function. C7 and SGT11 significantly decreased cortical inflammatory cytokines 3 h post-TBI.

CONCLUSIONS

Using sleep as a bio-indicator of TNF-R-dependent neuroinflammation, we identified C7 and SGT11 as potential therapeutic candidates for TBI.

A Review of the Health Benefits of Cherries

Increased oxidative stress contributes to development and progression of several human chronic inflammatory diseases. Cherries are a rich source of polyphenols and vitamin C which have anti-oxidant and anti-inflammatory properties. Our aim is to summarize results from human studies regarding health benefits of both sweet and tart cherries, including products made from them (juice, powder, concentrate, capsules); all referred to as cherries here. We found 29 (tart 20, sweet 7, unspecified 2) published human studies which examined health benefits of consuming cherries. Most of these studies were less than 2 weeks of duration (range 5 h to 3 months) and served the equivalent of 45 to 270 cherries/day (anthocyanins 55–720 mg/day) in single or split doses. Two-thirds of these studies were randomized and placebo controlled. Consumption of cherries decreased markers for oxidative stress in 8/10 studies; inflammation in 11/16; exercise-induced muscle soreness and loss of strength in 8/9; blood pressure in 5/7; arthritis in 5/5, and improved sleep in 4/4. Cherries also decreased hemoglobin A1C (HbA1C), Very-low-density lipoprotein (VLDL) and triglycerides/high-density lipoprotein (TG/HDL) in diabetic women, and VLDL and TG/HDL in obese participants. These results suggest that consumption of sweet or tart cherries can promote health by preventing or decreasing oxidative stress and inflammation.

Tumor necrosis factor alpha in sleep regulation

This review details tumor necrosis factor alpha (TNF) biology and its role in sleep, and describes how TNF medications influence sleep/wake activity. Substantial evidence from healthy young animals indicates acute enhancement or inhibition of endogenous brain TNF respectively promotes and inhibits sleep. In contrast, the role of TNF in sleep in most human studies involves pathological conditions associated with chronic elevations of systemic TNF and disrupted sleep. Normalization of TNF levels in such patients improves sleep. A few studies involving normal healthy humans and their TNF levels and sleep are consistent with the animal studies but are necessarily more limited in scope. TNF can act on established sleep regulatory circuits to promote sleep and on the cortex within small networks, such as cortical columns, to induce sleep-like states. TNF affects multiple synaptic functions, e.g., its role in synaptic scaling is firmly established. The TNF-plasticity actions, like its role in sleep, can be local network events suggesting that sleep and plasticity share biochemical regulatory mechanisms and thus may be inseparable from each other. We conclude that TNF is involved in sleep regulation acting within an extensive tightly orchestrated biochemical network to niche-adapt sleep in health and disease.

Genetic and neuronal regulation of sleep by neuropeptide VF

Sleep is an essential and phylogenetically conserved behavioral state, but it remains unclear to what extent genes identified in invertebrates also regulate vertebrate sleep. RFamide-related neuropeptides have been shown to promote invertebrate sleep, and here we report that the vertebrate hypothalamic RFamide neuropeptide VF (NPVF) regulates sleep in the zebrafish, a diurnal vertebrate. We found that NPVF signaling and npvf-expressing neurons are both necessary and sufficient to promote sleep, that mature peptides derived from the NPVF preproprotein promote sleep in a synergistic manner, and that stimulation of npvf-expressing neurons induces neuronal activity levels consistent with normal sleep. These results identify NPVF signaling and npvf-expressing neurons as a novel vertebrate sleep-promoting system and suggest that RFamide neuropeptides participate in an ancient and central aspect of sleep control.

Signs of enhanced sleep and sleep-associated memory processing following the anti-inflammatory antibiotic minocycline in men

Pro-inflammatory cytokines can promote sleep and neuronal processes underlying memory formation. However, this has mainly been revealed in animal studies. In this double-blind, placebo-controlled within-subject designed study, we examined how changes in the balance between pro- and anti-inflammatory signalling affect sleep and sleep-associated memory consolidation in humans. After learning declarative memory tasks (word pairs, texts) and a procedural memory task (finger tapping) in the evening, 21 healthy young men orally received either 200 mg of the anti-inflammatory antibiotic minocycline or placebo shortly before nocturnal sleep. Sleep was allowed between 23:00 and 07:00 h and recorded polysomnographically. Retrieval of memories was tested two days later. Because of outliers or missing data, final sample size was reduced to n = 14-19. Our data suggest that rather than weakening sleep as expected based on animal studies, the anti-inflammatory agent promoted sleep and memory consolidation. Specifically, minocycline increased slow-wave activity (0.68-4.0 Hz) during non-rapid eye movement sleep stage 2 and selectively enhanced episodic aspects in memory (i.e. memory for the temporal order of events in the texts). In combination with previous results, our findings indicate that, in humans, reducing pro-inflammatory signalling can act towards deepening non-rapid eye movement sleep and enhancing its memory forming efficacy.

Associations of Self-Reported Sleep Quality with Circulating Interferon Gamma-Inducible Protein 10, Interleukin 6, and High-Sensitivity C-Reactive Protein in Healthy Menopausal Women

Introduction

Sleep disturbance is very common in menopausal women and poor sleep quality has been linked to systemic inflammation. However, the impact of poor sleep quality on health outcomes of menopausal women remains unclear. This study evaluated the relationships between sleep quality and inflammation in menopausal women.

Participants and design

This cross-sectional study enrolled 281 healthy women aged 45 to 60 years. The Pittsburgh Sleep Quality Index (PSQI) was used to measure quality of sleep. Multiplex assays were used to measure the levels of 9 cytokines in morning fasting plasma samples. Other variables measured in this study included clinical characteristics and high-sensitivity C-reactive protein (hs-CRP).

Setting

The study was performed at a medical center.

Results

The 281 participants comprised 79 (28%) perimenopausal women and 202 (72%) postmenopausal women. Global PSQI scores were positively correlated with plasma hs-CRP levels (P = 0.012) and were marginally associated with interferon gamma-inducible protein-10 (IP10), interleukin 6 (IL6), and macrophage inflammatory protein-1beta (MIP-1β) levels. After adjusting for age, body mass index, menopause duration, and follicle stimulating hormone, multiple linear regression analysis revealed that high PSQI scores and sleep efficiency < 65% were associated with elevated plasma levels of hs-CRP, IP10, and IL6. In addition, sleep duration < 5 hours was associated with high hs-CRP levels.

Conclusion

Our data show that poor sleep quality and low sleep efficiency are associated with elevated levels of circulating inflammatory factors IP10, IL6 and hs-CRP and that short sleep duration is associated with high levels of hs-CRP in menopausal women. These findings provide novel evidence that poor sleep quality is linked to low-grade systemic inflammation in menopausal women.

Vedolizumab Therapy Is Associated with an Improvement in Sleep Quality and Mood in Inflammatory Bowel Diseases

INTRODUCTION

Poor sleep, depression, and anxiety are common in patients with inflammatory bowel diseases (IBD) and associated with increased risk of relapse and poor outcomes. The effectiveness of therapies in improving such psychosocial outcomes is unclear but is an important question to examine with increasing selectivity of therapeutic agents.

METHODS

This prospective cohort enrolled patients with moderate-to-severe CD or UC starting biologic therapy with vedolizumab or anti-tumor necrosis factor α agents (anti-TNF). Sleep quality, depression, and anxiety were measured using validated short-form NIH PROMIS questionnaires assessing sleep and mood quality over the past 7 days. Disease activity was assessed using validated indices. Improvement in sleep and mood scores from baseline was assessed, and regression models were used to identify determinants of sleep quality.

RESULTS

Our study included 160 patients with IBD (49 anti-TNF, 111 Vedolizumab) among whom half were women and the mean age was 40.2 years. In the combined cohort, we observed a statistically significant and meaningful decrease in mean scores from baseline (52.8) by week 6 (49.8, p = 0.002). Among vedolizumab users, sleep T-score improved from baseline (53.6) by week 6 (50.7) and persisted through week 54 (46.5, p = 0.009). Parallel reductions in depression and anxiety were also noted (p < 0.05 by week 6). We observed no difference in improvement in sleep, depression, and anxiety between vedolizumab and anti-TNF use at week 6.

CONCLUSIONS

Both vedolizumab and anti-TNF biologic therapies were associated with improvement in sleep and mood quality in IBD.

Poor sleep quality is associated with greater circulating pro-inflammatory cytokines and severity and frequency of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) symptoms in women

OBJECTIVE

Poor sleep quality has been linked to inflammatory processes and worse disease outcomes in the context of many chronic illnesses, but less is known in conditions such as chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). This study examines the relationships between sleep quality, pro-inflammatory cytokines, and CFS/ME symptoms.

METHODS

Sixty women diagnosed with CFS/ME were assessed using the Pittsburgh Sleep Quality Index (PSQI), Fatigue Symptom Inventory (FSI) and Center for Disease Control and Prevention (CDC)-based CFS/ME symptom questionnaires. Circulating plasma pro-inflammatory cytokine levels were measured by ELISA. Multiple regression analyses examined associations between sleep, cytokines and symptoms, controlling for age, education, and body mass index.

RESULTS

Poor sleep quality (PSQI global score) was associated with greater pro-inflammatory cytokine levels: interleukin-1β (IL-1β) (β=0.258, p=0.043), IL-6 (β=0.281, p=0.033), and tumor necrosis factor-alpha (TNF-α) (β=0.263, p=0.044). Worse sleep quality related to greater fatigue severity (β=0.395, p=0.003) and fatigue-related interference with daily activities (β=0.464, p<0.001), and more severe and frequent CDC-defined core CFS/ME symptoms (β=0.499, p<0.001, and β=0.556, p<0.001, respectively).

CONCLUSIONS

Results underscore the importance of managing sleep-related difficulties in this patient population. Further research is needed to identify the etiology of sleep disruptions in CFS/ME and mechanistic factors linking sleep quality to symptom severity and inflammatory processes.

Clinical relevance of midline fluid percussion brain injury: Acute deficits, chronic morbidities and the utility of biomarkers

BACKGROUND

After 30 years of characterisation and implementation, fluid percussion injury (FPI) is firmly recognised as one of the best-characterised reproducible and clinically relevant models of TBI, encompassing concussion through diffuse axonal injury (DAI). Depending on the specific injury parameters (e.g. injury site, mechanical force), FPI can model diffuse TBI with or without a focal component and may be designated as mild-to-severe according to the chosen mechanical forces and resulting acute neurological responses. Among FPI models, midline FPI may best represent clinical diffuse TBI, because of the acute behavioural deficits, the transition to late-onset behavioural morbidities and the absence of gross histopathology.

REVIEW

The goal here was to review acute and chronic physiological and behavioural deficits and morbidities associated with diffuse TBI induced by midline FPI. In the absence of neurodegenerative sequelae associated with focal injury, there is a need for biomarkers in the diagnostic, prognostic, predictive and therapeutic approaches to evaluate outcomes from TBI.

CONCLUSIONS

The current literature suggests that midline FPI offers a clinically-relevant, validated model of diffuse TBI to investigators wishing to evaluate novel therapeutic strategies in the treatment of TBI and the utility of biomarkers in the delivery of healthcare to patients with brain injury.

Stress and Withdrawal from Chronic Ethanol Induce Selective Changes in Neuroimmune mRNAs in Differing Brain Sites

Stress is a strong risk factor in alcoholic relapse and may exert effects that mimic aspects of chronic alcohol exposure on neurobiological systems. With the neuroimmune system becoming a prominent focus in the study of the neurobiological consequences of stress, as well as chronic alcohol exposure proving to be a valuable focus in this regard, the present study sought to compare the effects of stress and chronic ethanol exposure on induction of components of the neuroimmune system. Rats were exposed to either 1 h exposure to a mild stressor (restraint) or exposure to withdrawal from 15 days of chronic alcohol exposure (i.e., withdrawal from chronic ethanol, WCE) and assessed for neuroimmune mRNAs in brain. Restraint stress alone elevated chemokine (C–C motif) ligand 2 (CCL2), interleukin-1-beta (IL-1β), tumor necrosis factor alpha (TNFα) and toll-like receptor 4 (TLR4) mRNAs in the cerebral cortex within 4 h with a return to a control level by 24 h. These increases were not accompanied by an increase in corresponding proteins. Withdrawal from WCE also elevated cytokines, but did so to varying degrees across different cytokines and brain regions. In the cortex, stress and WCE induced CCL2, TNFα, IL-1β, and TLR4 mRNAs. In the hypothalamus, only WCE induced cytokines (CCL2 and IL-1β) while in the hippocampus, WCE strongly induced CCL2 while stress and WCE induced IL-1β. In the amygdala, only WCE induced CCL2. Finally—based on the previously demonstrated role of corticotropin-releasing factor 1 (CRF1) receptor inhibition in blocking WCE-induced cytokine mRNAs—the CRF1 receptor antagonist CP154,526 was administered to a subgroup of stressed rats and found to be inactive against induction of CCL2, TNFα, or IL-1β mRNAs. These differential results suggest that stress and WCE manifest broad neuroimmune effects in brain depending on the cytokine and brain region, and that CRF inhibition may not be a relevant mechanism in non-alcohol exposed animals. Overall, these effects are complex in terms of their neuroimmune targets and neuroanatomical specificity. Further investigation of the differential distribution of cytokine induction across neuroanatomical regions, individual cell types (e.g., neuronal phenotypes and glia), severity of chronic alcohol exposure, as well as across differing stress types may prove useful in understanding differential mechanisms of induction and for targeting select systems for pharmacotherapeutic intervention in alcoholism.

Resolvins AT-D1 and E1 differentially impact functional outcome, post-traumatic sleep, and microglial activation following diffuse brain injury in the mouse

Traumatic brain injury (TBI) is induced by mechanical forces which initiate a cascade of secondary injury processes, including inflammation. Therapies which resolve the inflammatory response may promote neural repair without exacerbating the primary injury. Specific derivatives of omega-3 fatty acids loosely grouped as specialized pro-resolving lipid mediators (SPMs) and termed resolvins promote the active resolution of inflammation. In the current study, we investigate the effect of two resolvin molecules, RvE1 and AT-RvD1, on post-traumatic sleep and functional outcome following diffuse TBI through modulation of the inflammatory response. Adult, male C57BL/6 mice were injured using a midline fluid percussion injury (mFPI) model (6-10min righting reflex time for brain-injured mice). Experimental groups included mFPI administered RvE1 (100ng daily), AT-RvD1 (100ng daily), or vehicle (sterile saline) and counterbalanced with uninjured sham mice. Resolvins or saline were administered daily for seven consecutive days beginning 3days prior to TBI to evaluate proof-of-principle to improve outcome. Immediately following diffuse TBI, post-traumatic sleep was recorded for 24h post-injury. For days 1-7 post-injury, motor outcome was assessed by rotarod. Cognitive function was measured at 6days post-injury using novel object recognition (NOR). At 7days post-injury, microglial activation was quantified using immunohistochemistry for Iba-1. In the diffuse brain-injured mouse, AT-RvD1 treatment, but not RvE1, mitigated motor and cognitive deficits. RvE1 treatment significantly increased post-traumatic sleep in brain-injured mice compared to all other groups. RvE1 treated mice displayed a higher proportion of ramified microglia and lower proportion of activated rod microglia in the cortex compared to saline or AT-RvD1 treated brain-injured mice. Thus, RvE1 treatment modulated post-traumatic sleep and the inflammatory response to TBI, albeit independently of improvement in motor and cognitive outcome as seen in AT-RvD1-treated mice. This suggests AT-RvD1 may impart functional benefit through mechanisms other than resolution of inflammation alone.

Sleep-disordered breathing in patients with cystic fibrosis

OBJECTIVE

To test the hypothesis that disease severity in patients with cystic fibrosis (CF) is correlated with an increased risk of sleep apnea.

METHODS

A total of 34 CF patients underwent clinical and functional evaluation, as well as portable polysomnography, spirometry, and determination of IL-1β levels.

RESULTS

Mean apnea-hypopnea index (AHI), SpO2 on room air, and Epworth Sleepiness Scale score were 4.8 ± 2.6, 95.9 ± 1.9%, and 7.6 ± 3.8 points, respectively. Of the 34 patients, 19 were well-nourished, 6 were at nutritional risk, and 9 were malnourished. In the multivariate model to predict the AHI, the following variables remained significant: nutritional status (β = -0.386; p = 0.014); SpO2 (β = -0.453; p = 0.005), and the Epworth Sleepiness Scale score (β = 0.429; p = 0.006). The model explained 51% of the variation in the AHI.

CONCLUSIONS

The major determinants of sleep apnea were nutritional status, SpO2, and daytime sleepiness. This knowledge not only provides an opportunity to define the clinical risk of having sleep apnea but also creates an avenue for the treatment and prevention of the disease.

Effects of an interleukin-1 receptor antagonist on human sleep, sleep-associated memory consolidation, and blood monocytes

Pro-inflammatory cytokines like interleukin-1 beta (IL-1) are major players in the interaction between the immune system and the central nervous system. Various animal studies report a sleep-promoting effect of IL-1 leading to enhanced slow wave sleep (SWS). Moreover, this cytokine was shown to affect hippocampus-dependent memory. However, the role of IL-1 in human sleep and memory is not yet understood. We administered the synthetic IL-1 receptor antagonist anakinra (IL-1ra) in healthy humans (100mg, subcutaneously, before sleep; n=16) to investigate the role of IL-1 signaling in sleep regulation and sleep-dependent declarative memory consolidation. Inasmuch monocytes have been considered a model for central nervous microglia, we monitored cytokine production in classical and non-classical blood monocytes to gain clues about how central nervous effects of IL-1ra are conveyed. Contrary to our expectation, IL-1ra increased EEG slow wave activity during SWS and non-rapid eye movement (NonREM) sleep, indicating a deepening of sleep, while sleep-associated memory consolidation remained unchanged. Moreover, IL-1ra slightly increased prolactin and reduced cortisol levels during sleep. Production of IL-1 by classical monocytes was diminished after IL-1ra. The discrepancy to findings in animal studies might reflect species differences and underlines the importance of studying cytokine effects in humans.

Environmental disruption of the circadian clock leads to altered sleep and immune responses in mouse

In mammals, one of the most salient outputs of the circadian (daily) clock is the timing of the sleep-wake cycle. Modern industrialized society has led to a fundamental breakdown in the relationship between our endogenous timekeeping systems and the solar day, disrupting normal circadian rhythms. We have argued that disrupted circadian rhythms could lead to changes in allostatic load, and the capacity of organisms to respond to other environmental challenges. In this set of studies, we apply a model of circadian disruption characterized in our lab in which mice are housed in a 20h long day, with 10h of light and 10h of darkness. We explored the effects of this environmental disruption on sleep patterns, to establish if this model results in marked sleep deprivation. Given the interaction between circadian, sleep, and immune systems, we further probed if our model of circadian disruption also alters the innate immune response to peripheral bacterial endotoxin challenge. Our results demonstrate that this model of circadian disruption does not lead to marked sleep deprivation, but instead affects the timing and quality of sleep. We also show that while circadian disruption does not lead to basal changes in the immune markers we explored, the immune response is affected, both in the brain and the periphery. Together, our findings further strengthen the important role of the circadian timing system in sleep regulation and immune responses, and provide evidence that disrupting the circadian clock increases vulnerability to further environmental stressors, including immunological challenges.

Paradoxical sleep deprivation impairs mouse survival after infection with malaria parasites

Background

Parasitic diseases like malaria are a major public health problem in many countries and disrupted sleep patterns are an increasingly common part of modern life. The aim of this study was to assess the effects of paradoxical sleep deprivation (PSD) and sleep rebound (RB) on malarial parasite infection in mice.

Methods

After PSD, one group was immediately infected with parasites (PSD). The two other PSD rebound groups were allowed to sleep normally for either 24 h (24 h RB) or 48 h (48 h RB). After the recovery periods, mice were inoculated with parasites.

Results

The PSD group was the most affected by parasites presenting the higher death rate (0.02), higher number of infected cells (p < 0.01), and decrease in body weight (p < 0.04) compared to control and 48 h RB groups. The 24 h RB group was also different from control group in survival (p < 0.03), number of infected cells (p < 0.05) and body weight (p < 0.04). After 48 hours of sleep rebound animals were allowed to restore their response to parasitic infection similar to normal sleep animals.

Conclusions

These results suggest that PSD is damaging to the immune system and leads to an increased infection severity of malaria parasites; only 48 hours of recovery sleep was sufficient to return the mice infection response to baseline values.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-015-0690-7) contains supplementary material, which is available to authorized users.

Polysomnographic characteristics in nonmalignant chronic pain populations: A review of controlled studies

Sleep and pain are critical homeostatic systems that interact in a bidirectional manner. Complaints of sleep disturbance are ubiquitous among patients with chronic pain disorders, and conversely, patients with persistent insomnia symptoms commonly report suffering from chronic pain. Sleep deprivation paradigms demonstrate that partial or complete sleep loss induce hyperalgesia, possibly due to shared mechanistic pathways including neuroanatomic and molecular substrates. Further, chronic pain conditions and sleep disturbances are intertwined through comorbidities, which together cause detrimental psychological and physical consequences. This critical review examines 29 polysomnography studies to evaluate whether nonmalignant chronic pain patients, as compared to controls, show differences in objective measures of sleep continuity and sleep architecture. Whereas these controlled studies did not reveal a consistent pattern of objective sleep disturbances, alterations of sleep continuity were commonly reported. Alterations of sleep architecture such as increases in light sleep or decreases in slow-wave sleep were less commonly reported and findings were mixed and also inconsistent. Methodological flaws were identified, which complicated interpretation and limited conclusions; hence, recommendations for future research are suggested. Knowledge of abnormalities in the sleep process has implications for understanding the pathophysiology of chronic pain conditions, which might also direct the development of novel intervention strategies.

The effects of dexamethasone on sleep in young children with acute lymphoblastic leukemia

PURPOSE

Corticosteroids, which are a mainstay in the treatment of acute lymphoblastic leukemia (ALL), have a well-documented adverse effect on sleep. We sought to characterize the effects of dexamethasone on sleep over an entire 28-day treatment cycle using actigraphy, an objective measure of sleep.

METHODS

The sleep of 25 children aged 2-9 years (mean 4.5 years) with ALL treated with dexamethasone were evaluated during maintenance chemotherapy using a within-subject experimental design, actigraphy, and standardized questionnaires to assess sleep, sleep problems, and fatigue.

RESULTS

During the five days of dexamethasone treatment, sleep time increased during the night (535 vs. 498 min; p = 0.004) and daytime napping increased the following day (14 vs. 0 min; p = 0.002), and the number of wake episodes during the night was lower (14 vs. 20; p =  ≤ 0.001). However, when assessed individually, sleep-onset time, efficiency, and wake after sleep onset during the night were unchanged during dexamethasone treatment; when the cumulative effect of all of these factors was assessed, there was a statistically and clinically significant increase in nighttime sleep duration during dexamethasone treatment.

CONCLUSIONS

During the five days of treatment with dexamethasone, an increase in nighttime sleep as well as daytime napping was observed in young children with ALL. The increases in sleep duration return to baseline one day after the discontinuation of dexamethasone.

Influence of JuA in evoking communication changes between the small intestines and brain tissues of rats and the GABAA and GABAB receptor transcription levels of hippocampal neurons

ETHNOPHARMACOLOGICAL RELEVANCE

Jujuboside A (JuA) is a main active ingredient of semen ziziphi spinosae, which can significantly reduce spontaneous activity in mammals, increase the speed of falling asleep, prolong the sleeping time as well as improve the sleeping efficiency. In this study, the mechanism and the pathway of the sedative and hypnotic effect of JuA were investigated.

MATERIALS AND METHODS

After being treated with JuA (in vitro), the rat׳s small intestine tissues cultures were used to stimulate the brain tissues. Then 27 cytokine levels were detected in the two kinds of tissue culture via liquid protein chip technology; In addition, the cultured hippocampal neurons of rat were treated with JuA, and γ-aminobutyric acid (GABA) receptor subunits (GABAAα1, GABAAα5, GABAAβ1 and GABABR1) mRNAs were evaluated by Real-time PCR.

RESULTS

The levels of IL-1α, MIP-1α, IL-1β and IL-2 were reduced significantly after 3h of treating the small intestine tissues with JuA (200µl/ml), and the concentration change rates, in order, were -59.3%, -3.59%, -50.1% and -49.4%; these cytokines were transmitted to brain tissues 2h later, which could lead to significant levels of reduction of IL-1α, IFN-γ, IP-10 and TNF-α; the concentration change rates were -62.4%, -25.7%, -55.2% and -38.5%, respectively. Further, the intercellular communication network diagram was mapped out, which could suggest the mechanism and the pathway of the sedative and hypnotic effect of JuA. The results also indicated that JuA (50µl/ml) increased significantly GABAAα1 receptor mRNAs and reduced GABABR1, mRNAs in hippocampal neurons after 24h of stimulation; however, all the mRNA transcription levels of GABAAα1,GABAAα5, GABAAβ1 and GABABR1 receptors increased significantly after 48h.

CONCLUSION

JuA performed its specific sedative and hypnotic effect through not only adjusting GABA receptors subunit mRNAs expression, but also down-regulating the secretion of relevant inflammation cytokines on the intestinal mucosal system to affect the intercellular cytokine network between nerve cells in the brain. This mechanism is similar to that of melatonin.