Cytokines and normal sleep

The role of ATP in sleep-wake regulation: In adenosine-dependent and -independent manner

ATP plays a crucial role as an energy currency in the body's various physiological functions, including the regulation of the sleep-wake cycle. Evidence from genetics and pharmacology demonstrates a strong association between ATP metabolism and sleep. With the advent of new technologies such as optogenetics, genetically encoded biosensors, and novel ATP detection methods, the dynamic changes in ATP levels between different sleep states have been further uncovered. The classic mechanism for regulating sleep by ATP involves its conversion to adenosine, which increases sleep pressure when accumulated extracellularly. However, emerging evidence suggests that ATP can directly bind to P2 receptors and influence sleep-wake regulation through both adenosine-dependent and independent pathways. The outcome depends on the brain region where ATP acts and the expression type of P2 receptors. This review summarizes the experimental evidence on the relationship between ATP levels and changes in sleep states and outlines the mechanisms by which ATP is involved in regulating the sleep-wake cycle through both adenosine-dependent and independent pathways. Hopefully, this review will provide a comprehensive understanding of the current research basis and progress in this field and promote further investigations into the specific mechanisms of ATP in regulating sleep.

Effect of glucocorticoid blockade on inflammatory responses to acute sleep fragmentation in male mice

The association between sleep and the immune-endocrine system is well recognized, but the nature of that relationship is not well understood. Sleep fragmentation induces a pro-inflammatory response in peripheral tissues and brain, but it also activates the hypothalamic-pituitary-adrenal (HPA) axis, releasing glucocorticoids (GCs) (cortisol in humans and corticosterone in mice). It is unclear whether this rapid release of glucocorticoids acts to potentiate or dampen the inflammatory response in the short term. The purpose of this study was to determine whether blocking or suppressing glucocorticoid activity will affect the inflammatory response from acute sleep fragmentation (ASF). Male C57BL/6J mice were injected i.p. with either 0.9% NaCl (vehicle 1), metyrapone (a glucocorticoid synthesis inhibitor, dissolved in vehicle 1), 2% ethanol in polyethylene glycol (vehicle 2), or mifepristone (a glucocorticoid receptor antagonist, dissolved in vehicle 2) 10 min before the start of ASF or no sleep fragmentation (NSF). After 24 h, samples were collected from brain (prefrontal cortex, hypothalamus, hippocampus) and periphery (liver, spleen, heart, and epididymal white adipose tissue (EWAT)). Proinflammatory gene expression (TNF-α and IL-1β) was measured, followed by gene expression analysis. Metyrapone treatment affected pro-inflammatory cytokine gene expression during ASF in some peripheral tissues, but not in the brain. More specifically, metyrapone treatment suppressed IL-1β expression in EWAT during ASF, which implies a pro-inflammatory effect of GCs. However, in cardiac tissue, metyrapone treatment increased TNF-α expression in ASF mice, suggesting an anti-inflammatory effect of GCs. Mifepristone treatment yielded more significant results than metyrapone, reducing TNF-α expression in liver (only NSF mice) and cardiac tissue during ASF, indicating a pro-inflammatory role. Conversely, in the spleen of ASF-mice, mifepristone increased pro-inflammatory cytokines (TNF-α and IL-1β), demonstrating an anti-inflammatory role. Furthermore, irrespective of sleep fragmentation, mifepristone increased pro-inflammatory cytokine gene expression in heart (IL-1β), pre-frontal cortex (IL-1β), and hypothalamus (IL-1β). The results provide mixed evidence for pro- and anti-inflammatory functions of corticosterone to regulate inflammatory responses to acute sleep loss.

Sleep Disorders in Connective Tissue Diseases-Coexisting Diseases or Disease Components?

This comprehensive review examines the complex relationship between sleep disorders and rheumatic diseases, supported by findings from the latest research articles. It encompasses various rheumatic conditions, including rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis. The review reveals the bidirectional relationship between sleep disorders and these diseases, emphasizing their impact on disease progression and quality of life. Conventional and alternative therapeutic interventions for connective tissue diseases are presented, focusing on improving sleep quality and alleviating rheumatic symptoms. The role of pro-inflammatory cytokines and their potential modulation through pharmacological agents is also discussed. In the treatment of sleep disorders, various options are proposed, such as cognitive behavioral therapy for insomnia, physical activity, dietary modifications, and alternative approaches like reflexology and acupuncture. Thus, this review offers a nuanced understanding of the connection between sleep disorders and rheumatic diseases, supported by evidence from diverse studies. Such an approach is particularly important because it enhances sleep quality for overall patient well-being in the holistic management of rheumatic conditions.

Concussion and the Sleeping Brain

BACKGROUND

Emerging research has suggested sleep to be a modifier of the trajectory of concussion recovery in adolescent and adult populations. Despite the growing recognition of the relationship between sleep and concussion, the mechanisms and physiological processes governing this association have yet to be established.

MAIN BODY

Following a concussion, a pathophysiologic cascade of events occurs, characterized by numerous factors including microglia activation, ionic imbalance, and release of excitatory neurotransmitters. Importantly, each of these factors plays a role in the regulation of the sleep-wake cycle. Therefore, dysregulation of sleep following injury may be a function of the diffuse disruption of cerebral functioning in the wake of both axonal damage and secondary physiological events. As the onset of sleep-related symptoms is highly variable following a concussion, clinicians should be aware of when and how these symptoms present. Post-injury changes in sleep have been reported in the acute, sub-acute, and chronic phases of recovery and can prolong symptom resolution, affect neurocognitive performance, and influence mood state. Though these changes support sleep as a modifier of recovery, limited guidance exists for clinicians or their patients in the management of sleep after concussion. This may be attributed to the fact that research has correlated sleep with concussion recovery but has failed to explain why the correlation exists. Sleep is a complex, multifactorial process and the changes seen in sleep that are seen following concussion are the result of interactions amongst numerous processes that regulate the sleep-wake cycle.

SHORT CONCLUSION

The assessment and management of sleep by identifying and considering the biological, sociological, and psychological interactions of this multifactorial process will allow for clinicians to address the dynamic nature of changes in sleep following concussion.

Association of Tumor Necrosis Factor-Alpha, Interleukin-1β, Interleukin-8, and Interferon-γ with Obstructive Sleep Apnea in Both Children and Adults: A Meta-Analysis of 102 Articles

Background: Cytokines may have a significant impact on sleep regulation. In this meta-analysis, we present the serum/plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, IL-1β, and interferon-gamma (IFN-γ) in both children and adults with obstructive sleep apnea (OSA) in comparison to controls. Methods: Four electronic databases were systematically searched (PubMed, Web of Science, Scopus, and Cochrane Library) through 19 October 2023, without any restrictions on language, date, age, and sex. We used Review Manager version 5.3 to perform meta-analysis and presented the data as standardized mean difference (SMD) and 95% confidence interval (CI) values to evaluate the relationships between the levels of cytokines and OSA. Results: A total of 102 articles (150 independent studies) were included in the meta-analysis. The pooled SMDs in adults were 1.42 (95%CI: 1.11, 1.73; p < 0.00001), 0.85 (95%CI: 0.40, 1.31; p = 0.0002), 0.69 (95%CI: 0.22, 1.16; p = 0.004), and 0.39 (95%CI: -0.37, 1.16; p = 0.31) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. The pooled SMDs in children were 0.84 (95%CI: 0.35, 1.33; p = 0.0008), 0.60 (95%CI: 0.46, 0.74; p < 0.00001), 0.25 (95%CI: -0.44, 0.93; p = 0.49), and 3.70 (95%CI: 0.75, 6.65; p = 0.01) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. Conclusions: The levels of proinflammatory cytokines of TNF-α, IL-8, and IL-1β in adults, and TNF-α, IL-8, and IFN-γ in children with OSA, are significantly higher than those in controls.

Association of insomnia with incident chronic cognitive impairment in older adults with type 2 diabetes mellitus: A prospective study of the Hong Kong Diabetes Register

AIMS

To examine the risk association of insomnia with incident chronic cognitive impairment in older adults with type 2 diabetes mellitus (T2D).

METHODS

Between July 2010 and June 2015, patients with T2D aged ≥60 years enrolled in the Hong Kong Diabetes Register completed the Insomnia Severity Index (ISI) questionnaire. Patients were considered having insomnia if they had ISI score > 14. We prospectively followed up the cohort and censored outcome through reviewing diagnoses and clinical notes entered by attending physicians in electronic medical record to identify incident cases of mild cognitive impairment and dementia.

RESULTS

After excluding shift workers and those with established chronic cognitive impairment at baseline, we included 986 patients with T2D in this study (58.3 % men, mean age ± standard deviation: 62.5 ± 2.6 years, disease duration of diabetes: 10.7 ± 8.2 years, HbA1c: 7.4 ± 1.3 %, insulin users: 28.7 %, insomnia: 9.1 %). After a median follow-up of 7.6 (interquartile range = 2.0) years, 41 (4.2 %) developed chronic cognitive impairment. Using Cox regression analysis, insomnia (hazard ratio, HR 2.909, p = 0.012) and HbA1c ≥ 7 % (HR 2.300, p = 0.038) were positively associated with incident chronic cognitive impairment while insulin use (HR 0.309, p = 0.028) showed negative association.

CONCLUSIONS

Insomnia, suboptimal glycemic control and non-insulin use are independent risk factors for incident chronic cognitive impairment in older adults with T2D.

Weight Loss and Sleep, Current Evidence in Animal Models and Humans

Sleep is a vital process essential for survival. The trend of reduction in the time dedicated to sleep has increased in industrialized countries, together with the dramatic increase in the prevalence of obesity and diabetes. Short sleep may increase the risk of obesity, diabetes and cardiovascular disease, and on the other hand, obesity is associated with sleep disorders, such as obstructive apnea disease, insomnia and excessive daytime sleepiness. Sleep and metabolic disorders are linked; therefore, identifying the physiological and molecular pathways involved in sleep regulation and metabolic homeostasis can play a major role in ameliorating the metabolic health of the individual. Approaches aimed at reducing body weight could provide benefits for both cardiometabolic risk and sleep quality, which indirectly, in turn, may determine an amelioration of the cardiometabolic phenotype of individuals. We revised the literature on weight loss and sleep, focusing on the mechanisms and the molecules that may subtend this relationship in humans as in animal models.

Do Sleep Disturbances have a Dual Effect on Alzheimer's Disease?

Sleep disturbances and Alzheimer's disease have deleterious effects on various physiological and cognitive functions including synaptic plasticity, oxidative stress, neuroinflammation, and memory. In addition, clock genes expression is significantly altered following sleep disturbances, which may be involved in the pathogenesis of Alzheimer's disease. In this review article, we aimed to discuss the role of sleep disturbances and Alzheimer's disease in the regulation of synaptic plasticity, oxidative stress, neuroinflammation, and clock genes expression. Also, we aimed to find significant relationships between sleep disturbances and Alzheimer's disease in the modulation of these mechanisms. We referred to the controversial effects of sleep disturbances (particularly those related to the duration of sleep deprivation) on the modulation of synaptic function and neuroinflammation. We aimed to know that, do sleep disturbances have a dual effect on the progression of Alzheimer's disease? Although numerous studies have discussed the association between sleep disturbances and Alzheimer's disease, the new point of this study was to focus on the controversial effects of sleep disturbances on different biological functions, and to evaluate the potential dualistic role of sleep disturbances in the pathogenesis of Alzheimer's disease.

Narcolepsy-Like Sleepiness: A Symptom of Immediate-Type Reactions in Food-Allergic Children

BACKGROUND

It has been reported that sometimes children fall asleep and can barely be woken up during allergic reactions on food ingestion. Nevertheless, to date, there is scarce data on narcolepsy-like sleepiness as a symptom of allergic reactions.

OBJECTIVE

To investigate the frequency of narcolepsy-like sleepiness during oral food challenges and characterize this symptom regarding comorbidities, eliciting allergens, and severity of reactions.

METHODS

Children with immediate-type allergic reactions during oral food challenges (89% were double-blind, placebo-controlled) have been analyzed in this study. Narcolepsy-like sleepiness was defined as a somnolent condition during which patients could barely be woken up again, occurring within 2 hours of food intake and which was not due to drug side effects. Logistic generalized estimating equations were used to explore the effect of age, severity of reactions, and eliciting allergens on the occurrence of narcolepsy-like sleepiness.

RESULTS

In 106 (12.5%) of all 848 food-allergic children, narcolepsy-like sleepiness was observed during oral food challenges. Children with eczema had a higher risk of developing narcolepsy-like sleepiness (P = .006). Narcolepsy-like sleepiness occurred most often due to an allergic reaction to hazelnut (P = .009) or other tree nuts (P = .003). Moderate to severe reactions occurred more often than mild reactions (P = .026; odds ratio, 1.521; 95% CI, 1.051-2.202) in children with narcolepsy-like sleepiness.

CONCLUSIONS

We were able to show for the first time that narcolepsy-like sleepiness is a frequently occurring clinical manifestation of immediate-type allergic reactions on food ingestion in childhood. Further research is needed to unravel the underlying mechanisms to gain a deeper insight into this underestimated symptom.

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.

Sleep, neuronal hyperexcitability, inflammation and neurodegeneration: Does early chronic short sleep trigger and is it the key to overcoming Alzheimer's disease?

Evidence links neuroinflammation to Alzheimer's disease (AD); however, its exact contribution to the onset and progression of the disease is poorly understood. Symptoms of AD can be seen as the tip of an iceberg, consisting of a neuropathological build-up in the brain of extracellular amyloid-β (Aβ) plaques and intraneuronal hyperphosphorylated aggregates of Tau (pTau), which are thought to stem from an imbalance between its production and clearance resulting in loss of synaptic health and dysfunctional cortical connectivity. The glymphatic drainage system, which is particularly active during sleep, plays a key role in the clearance of proteinopathies. Poor sleep can cause hyperexcitability and promote Aβ and tau pathology leading to systemic inflammation. The early neuronal hyperexcitability of γ-aminobutyric acid (GABA)-ergic inhibitory interneurons and impaired inhibitory control of cortical pyramidal neurons lie at the crossroads of excitatory/inhibitory imbalance and inflammation. We outline, with a prospective framework, a possible vicious spiral linking early chronic short sleep, neuronal hyperexcitability, inflammation and neurodegeneration. Understanding the early predictors of AD, through an integrative approach, may hold promise for reducing attrition in the late stages of neuroprotective drug development.

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.

Restless Leg Syndrome and Sleep Disorders in Patients with Rheumatoid Arthritis and Its Relation with Anemia Parameters

OBJECTIVES

We aimed to investigate the prevalence of restless legs syndrome (RLS) and sleep disorders in patients with rheumatoid arthritis (RA), and the association of iron deficiency with them.

MATERIALS AND METHODS

The study included 72 patients with RA (59 females, 13 males), and 50 healthy control subjects (57 females, 15 males). Assessments were made using the International RLS Rating Scale, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale, Fatigue Severity Scale (FSS), Beck anxiety and depression index and the SF-36 quality of life scores.

RESULTS

We found that the frequency of RLS in RA patients was 29.1% and 13.8% in healthy control (p = 0.021). RA patients had 44.4% iron deficiency and 5.5% anemia of chronic disease. We found that 52.3% of patients with iron deficiency had RLS. There was an independent relationship between present of RLS and FSS (Beta [β] = 0.317, p = 0.005) and total iron binding capacity (TIBC) (β = 0.244, p = 0.031). There was an independent relationship between RLS severity score and PSQI (β = 0.264, p = 0.025) and social functionality (β = 0.302, p = 0.009).

CONCLUSION

The prevalence of iron deficiency is high in RA in the developing countries. Analysis obtained in patients with RA is suggestive of an association between iron deficiency and increased frequency of RLS. The presence of RLS in patients with RA negatively affects sleep quality, psychiatric status, and quality of life of patients with RA. TIBC value may be a predictive marker for early detection of RLS in patients with RA.

Electroacupuncture: A New Approach for Improved Postoperative Sleep Quality After General Anesthesia

General anesthesia produces a state of drug-induced unconsciousness that is controlled by the extent and duration of administered agents. Whether inhalation or intravenous in formulation, such agents may interfere with normal sleep-wake cycles, impairing postoperative sleep quality and creating complications. Electroacupuncture is a new approach widely applied in clinical practice during recent years. This particular technology helps regulate neurotransmitter concentrations in the brain, lowering norepinephrine and dopamine levels to improve sleep quality. It also alleviates surgical pain that degrades postoperative sleep quality after general anesthesia by downregulating immune activity (SP, NK-1, and COX-1) and upregulating serotonin receptor (5-HT1AR, 5-HT2AR) and endocannabinoid expression levels. However, large-scale, multicenter studies are still needed to determine the optimal duration, frequency, and timing of electroacupuncture for such use.

Cardiorespiratory Alterations in a Newborn Ovine Model of Systemic Inflammation Induced by Lipopolysaccharide Injection

Although it is well known that neonatal sepsis can induce important alterations in cardiorespiratory control, their detailed early features and the mechanisms involved remain poorly understood. As a first step in resolving this issue, the main goal of this study was to characterize these alterations more extensively by setting up a full-term newborn lamb model of systemic inflammation using lipopolysaccharide (LPS) injection. Two 6-h polysomnographic recordings were performed on two consecutive days on eight full-term lambs: the first after an IV saline injection (control condition, CTRL); the second, after an IV injection of 2.5 μg/kg Escherichia coli LPS 0127:B8 (LPS condition). Rectal temperature, locomotor activity, state of alertness, arterial blood gases, respiratory frequency and heart rate, mean arterial blood pressure, apneas and cardiac decelerations, and heart-rate and respiratory-rate variability (HRV and RRV) were assessed. LPS injection decreased locomotor activity (p = 0.03) and active wakefulness (p = 0.01) compared to the CTRL. In addition, LPS injection led to a biphasic increase in rectal temperature (p = 0.01 at ∼30 and 180 min) and in respiratory frequency and heart rate (p = 0.0005 and 0.005, respectively), and to an increase in cardiac decelerations (p = 0.05). An overall decrease in HRV and RRV was also observed. Interestingly, the novel analysis of the representations of the horizontal and vertical visibility network yielded the most statistically significant alterations in HRV structure, suggesting its potential clinical importance for providing an earlier diagnosis of neonatal bacterial sepsis. A second goal was to assess whether the reflexivity of the autonomic nervous system was altered after LPS injection by studying the cardiorespiratory components of the laryngeal and pulmonary chemoreflexes. No difference was found. Lastly, preliminary results provide proof of principle that brainstem inflammation (increased IL-8 and TNF-α mRNA expression) can be shown 6 h after LPS injection. In conclusion, this full-term lamb model of systemic inflammation reproduces several important aspects of neonatal bacterial sepsis and paves the way for studies in preterm lambs aiming to assess both the effect of prematurity and the central neural mechanisms of cardiorespiratory control alterations observed during neonatal sepsis.

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.

Sleep- and time of day-linked RNA transcript expression in wild-type and IL1 receptor accessory protein-null mice

Sleep regulation involves interleukin-1β (IL1) family members, TNF, and circadian clock genes. Previously, we characterized spontaneous sleep and sleep after 8 h of sleep deprivation (SD) ending at zeitgeber time (ZT)4 and ZT16 in wild-type (WT) and IL1 receptor accessory protein (AcP)- and brain-specific AcP (AcPb)-knockout (KO) mice. Here, we applied quantitative reverse transcriptase polymerase chain reaction and Spearman gene pair expression correlation methods to characterize IL1, IL1 receptor 1 (IL1R1), AcP, AcPb, Period 1 (Per1), Clock, adenosine deaminase (Ada), peptidoglycan recognition protein 1 (Pglyrp1), and TNF mRNA expressions under conditions with distinct sleep phenotypes. In WT mice, IL1, IL1R1, AcP, Ada, and Clock mRNAs were higher at ZT4 (mid-sleep period) than at ZT16. mRNA expressions differed substantially in AcP and AcPb KO mice at those times. After SD ending at ZT4, only WT mice had a non-rapid eye movement sleep (NREMS) rebound, and AcPb and IL1R1 mRNA increases were unique to WT mice. In AcPb KO mice, which have spontaneous high EEG slow wave power, AcP and Pglyrp1 mRNAs were elevated relative to WT mice at ZT4. At ZT4, the AcPb KO - WT Spearman correlation difference networks showed high positive correlations between IL1R1 and IL1, Per1, and Clock and high negative correlations between TNF and Pglyrp1 and Ada. At ZT16, the WT mice gene pair expression network was mostly negative, whereas in AcP KO mice, which have substantially more rapid eye movement sleep than WT mice, it was all positive. We conclude that gene pair expression correlations depend on the presence of AcP and AcPb.NEW & NOTEWORTHY Spearman gene pair expression correlations depend upon the presence or absence of interleukin-1 receptor accessory protein and upon sleep phenotype.

Gut microbiome diversity is associated with sleep physiology in humans

The human gut microbiome can influence health through the brain-gut-microbiome axis. Growing evidence suggests that the gut microbiome can influence sleep quality. Previous studies that have examined sleep deprivation and the human gut microbiome have yielded conflicting results. A recent study found that sleep deprivation leads to changes in gut microbiome composition while a different study found that sleep deprivation does not lead to changes in gut microbiome. Accordingly, the relationship between sleep physiology and the gut microbiome remains unclear. To address this uncertainty, we used actigraphy to quantify sleep measures coupled with gut microbiome sampling to determine how the gut microbiome correlates with various measures of sleep physiology. We measured immune system biomarkers and carried out a neurobehavioral assessment as these variables might modify the relationship between sleep and gut microbiome composition. We found that total microbiome diversity was positively correlated with increased sleep efficiency and total sleep time, and was negatively correlated with wake after sleep onset. We found positive correlations between total microbiome diversity and interleukin-6, a cytokine previously noted for its effects on sleep. Analysis of microbiome composition revealed that within phyla richness of Bacteroidetes and Firmicutes were positively correlated with sleep efficiency, interleukin-6 concentrations and abstract thinking. Finally, we found that several taxa (Lachnospiraceae, Corynebacterium, and Blautia) were negatively correlated with sleep measures. Our findings initiate linkages between gut microbiome composition, sleep physiology, the immune system and cognition. They may lead to mechanisms to improve sleep through the manipulation of the gut microbiome.

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.

Sleep and Inflammatory Bowel Disease: An Important Bi-Directional Relationship

Sleep deprivation and lack of sleep are a significant public health concern. Several studies have suggested an intricate relationship between sleep, inflammation, and the immune system. Poor sleep has been described well in subjects with inflammatory bowel disease (IBD) and has been linked to disease activity and shown as a predictor for subclinical inflammation and a risk factor for relapse and poorer outcomes. This review describes the relationship between poor sleep, inflammation, and the immune system. Furthermore, the relationship between sleep and IBD are reviewed. The causes of poor sleep in inflammatory bowel disease patient is discussed. Potential therapeutic interventions for the management of common sleep disturbances are provided.

Association of asthma and sleep insufficiency among South Korean adolescents: analysis of web-based self-reported data from the Korean youth risk behavior web-based survey

Objectives: Weekend oversleep or catch-up sleep is common among adolescents, but relatively few data are available with regard to its effects on asthma. Our aim was to investigate whether weekend oversleep is associated with ever having asthma among Korean adolescents. Methods: We analyzed web-based self-reported data from the Korean Youth Risk Behavior Web-based Survey in 25,927 physician-diagnosed adolescent asthma cases and 266,160 non-asthma cases. Self-report questionnaires were used to assess socioeconomic status, health behaviors, psychological factors and sleep patterns. Multiple logistic regression after adjusting for factors was used to determine the association between sleep and asthma. Results: The asthma group slept less (≤5 hours: 23.9% vs. 22.8%) had a later weekend bedtime (≥1:00 AM: 58.1% vs. 57.8%), and an earlier weekend wake time (≤7:00 AM: 18.1% vs. 17.0%) compared to the non-asthma group. After multiple logistic regression, a sleep duration ≤5 hours (odds ratio (OR), 1.09; 95% confidence interval (CI), 1.04-1.14) and weekend "early bird" (weekend wake time ≤7:00 AM: OR, 1.03; 95% CI, 1.00-1.07) were significantly associated with an increased frequency of asthma. Long weekend catch-up sleep (weekend sleep duration minus weekday sleep duration ≥2 hours) was significantly associated with a decreased frequency of asthma (OR, 0.98; 95% CI, 0.94-0.99). Conclusion: Long weekend catch-up sleep, as an indicator of insufficient weekday sleep, is associated with a decreased frequency of asthma in Korean adolescents.

Postoperative sleep disorders and their potential impacts on surgical outcomes

Postoperative sleep disturbance is a common occurrence with significant adverse effects on patients including delayed recovery, impairment of cognitive function, pain sensitivity and cardiovascular events. The development of postoperative sleep disturbance is multifactorial and involves the surgical inflammatory response, the severity of surgical trauma, pain, anxiety, the use of anesthetics and environmental factors such as nocturnal noise and light levels. Many of these factors can be managed perioperatively to minimize the deleterious impact on sleep. Pharmacological and non-pharmacological treatment strategies for postoperative sleep disturbance include dexmedetomidine, zolpidem, melatonin, enhanced recovery after surgery (ERAS) protocol and controlling of environmental noise and light levels. It is likely that a combination of pharmacological and non-pharmacological therapies will have the greatest impact; however, further research is required before their use can be routinely recommended.

Sleep fragmentation delays wound healing in a mouse model of type 2 diabetes

Study Objectives

This study tested the hypothesis that sleep fragmentation (SF) delays wound healing in obese B6.BKS(D)-Leprdb/J (db/db) mice with impaired leptin signaling and type 2 diabetes compared with wild-type C57BL/6J (B6) mice.

Methods

Adult male mice (n = 34) were anesthetized and bilateral full-thickness excisional wounds were created on the back of each mouse. Half of the db/db and B6 mice were housed in SF cages equipped with a bar that moved across the cage floor every 2 min, 12 hr/day for 23 days. The other half of each group of mice was housed in the same room and did not experience SF. The dependent measures were number of days required to achieve wound closure, mRNA expression of four inflammatory mediators, blood glucose, insulin, and corticosterone.

Results

SF in the db/db mice caused a significant delay in wound healing relative to db/db mice with no SF. Days to achieve 50 per cent wound healing were 13.3 ± 0.4 with SF compared with 10.3 ± 0.7 without SF. All B6 mice achieved 50 per cent wound healing within 6 days and complete healing after 16 days. SF caused a significant increase in wound levels of TNF-α mRNA only in the db/db mice and an increase in corticosterone only in the B6 mice.

Conclusions

The delayed wound healing in obese, diabetic mice caused by SF is homologous to delayed wound healing in some patients with type 2 diabetes. The results support the interpretation that altered leptinergic signaling and inflammatory proteins contribute to delayed wound healing.

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.

Association between allergic and nonallergic rhinitis and obstructive sleep apnea

PURPOSE OF REVIEW

Allergic rhinitis and nonallergic rhinitis (NAR) are common disorders, which have been considered as potential risk factors for obstructive sleep apnea (OSA). This review summarizes the proposed underlying pathophysiological mechanisms to provide a better understanding of the relationship between these conditions.

RECENT FINDINGS

In adults, allergic rhinitis and NAR may be considered as symptoms potentiating, rather than risk potentiating factors in the pathophysiology of OSA, whereas in children, these are considered to be independent predictors for sleep-disordered breathing (SDB) and failure of adeno-tonsillectomy, the recommended first-line therapy for children with OSA. Current advances suggest IL-6 may be important in regulating the sleep-wake cycle, and serum soluble IL-6 receptor (sIL-6R) levels may reflect the severity of OSA. Elevated Th17/Treg ratio correlates positively with apnea-hypopnea index of OSA patients, and Th17 and Treg imbalances caused by allergic rhinitis and OSA, respectively, may possibly promote each other, leading to further imbalance. Moreover, obesity is a strong risk factor for OSA, and leptin plays an important role in ventilatory function and upper airway obstruction. The variant trigeminocardiac reflex and nasotrigeminal reflex may also be involved in the association between rhinitis and OSA.

SUMMARY

Allergic rhinitis/NAR and OSA are closely associated, and each condition can be detrimental to the other. Thus, clinicians should pay attention to the potential presence of allergic rhinitis/NAR in OSA patients and vice versa.

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.

Ca2+ -Dependent Hyperpolarization Pathways in Sleep Homeostasis and Mental Disorders

Although we are beginning to understand the neuronal and biochemical nature of sleep regulation, questions remain about how sleep is homeostatically regulated. Beyond its importance in basic physiology, understanding sleep may also shed light on psychiatric and neurodevelopmental disorders. Recent genetic studies in mammals revealed several non-secretory proteins that determine sleep duration. Interestingly, genes identified in these studies are closely related to psychiatric and neurodevelopmental disorders, suggesting that the sleep-wake cycle shares some common mechanisms with these disorders. Here we review recent sleep studies, including reverse and forward genetic studies, from the perspectives of sleep duration and homeostasis. We then introduce a recent hypothesis for mammalian sleep in which the fast and slow Ca²⁺ -dependent hyperpolarization pathways are pivotal in generating the SWS firing pattern and regulating sleep homeostasis, respectively. Finally, we propose that these intracellular pathways are potential therapeutic targets for achieving depolarization/hyperpolarization (D/H) balance in psychiatric and neurodevelopmental disorders.

The role of sleep in pemphigus: a review of mechanisms and perspectives

Pemphigus is an autoimmune bullous disease that causes the development of blisters and erosions on the skin and/or mucosa. Its inflammatory process is mediated by cytokines, which interact with sleep in a bidirectional manner. Pain, a frequent symptom due to pemphigus lesions, is well known to impair sleep quality. Depression is also associated with pemphigus and pro-inflammatory cytokines and may impair sleep. Additionally, a common relationship among other dermatological diseases and sleep has increasingly been described. Poor sleep quality is associated with an increased risk for autoimmune diseases, and insomnia is a comorbidity that has recently been associated with pemphigus. Thus, this review will explore the evidence supporting the likely bidirectional relationship between pemphigus and sleep quality and its possible mechanisms involved. This approach covering both pemphigus and sleep will open a research avenue for future studies focusing on the efficacy of the sleep disorders treatment in patients with pemphigus. In the long term, this may provide relevant information to dermatologists regarding new strategies for the management of pemphigus clinical condition, allowing possibly a better quality of life for the patients.

Interleukin-1 receptor (IL-1R) mediates epilepsy-induced sleep disruption

Background

Sleep disruptions are common in epilepsy patients. Our previous study demonstrates that homeostatic factors and circadian rhythm may mediate epilepsy-induced sleep disturbances when epilepsy occurs at different zeitgeber hours. The proinflammatory cytokine, interleukin-1 (IL-1), is a somnogenic cytokine and may also be involved in epileptogenesis; however, few studies emphasize the effect of IL-1 in epilepsy-induced sleep disruption. We herein hypothesized that IL-1 receptor type 1 (IL-1R1) mediates the pathogenesis of epilepsy and epilepsy-induced sleep disturbances. We determined the role of IL-1R1 by using IL-1R1 knockout (IL-1R1 −/− KO) mice.

Results

Our results elucidated the decrease of non-rapid eye movement (NREM) sleep during the light period in IL-1R −/− mice and confirmed the somnogenic role of IL-1R1. Rapid electrical amygdala kindling was performed to induce epilepsy at the particular zeitgeber time (ZT) point, ZT13. Our results demonstrated that seizure thresholds induced by kindling stimuli, such as the after-discharge threshold and successful kindling rates, were not altered in IL-1R −/− mice when compared to those obtained from the wildtype mice (IL-1R +/+ mice). This result suggests that IL-1R1 is not involved in kindling-induced epileptogenesis. During sleep, ZT13 kindling stimulation significantly enhanced NREM sleep during the subsequent 6 h (ZT13-18) in wildtype mice, and sleep returned to the baseline the following day. However, the kindling-induced sleep alteration was absent in the IL-1R −/− KO mice.

Conclusions

These results indicate that the IL-1 signal mediates epilepsy-induced sleep disturbance, but dose not participate in kindling-induced epileptogenesis.

Impact of Serum Cytokine Levels on EEG-Measured Arousal Regulation in Patients with Major Depressive Disorder and Healthy Controls

BACKGROUND

In major depressive disorder (MDD), findings include hyperstable regulation of brain arousal measured by electroencephalography (EEG) vigilance analysis and alterations in serum levels of cytokines. It is also known that cytokines affect sleep-wake regulation. This study investigated the relationship between cytokines and EEG vigilance in participants with MDD and nondepressed controls, and the influence of cytokines on differences in vigilance between the two groups.

METHODS

In 60 patients with MDD and 129 controls, 15-min resting-state EEG recordings were performed and vigilance was automatically assessed with the VIGALL 2.0 (Vigilance Algorithm Leipzig). Serum levels of the wakefulness-promoting cytokines interleukin (IL)-4, IL-10, IL-13 and somnogenic cytokines tumor necrosis factor-α, interferon-x03B3; and IL-2 were measured prior to the EEG.

RESULTS

Summed wakefulness-promoting cytokines, but not somnogenic cytokines, were significantly associated with the time course of EEG vigilance in the MDD group only. In both groups, IL-13 was significantly associated with the course of EEG vigilance. In MDD compared to controls, a hyperstable EEG vigilance regulation was found, significant for group and group × time course interaction. After controlling for wakefulness-promoting cytokines, differences in vigilance regulation between groups remained significant.

CONCLUSIONS

The present study demonstrated a relationship between wakefulness-promoting cytokines and objectively measured EEG vigilance as an indicator for brain arousal. Altered brain arousal regulation in MDD gives support for future evaluation of vigilance measures as a biomarker in MDD. Since interactions between cytokines and EEG vigilance only moderately differed between the groups and cytokine levels could not explain the group differences in EEG vigilance regulation, cytokines and brain arousal regulation are likely to be associated with MDD in independent ways.

Sleep as spatiotemporal integration of biological processes that evolved to periodically reinforce neurodynamic and metabolic homeostasis: The 2m3d paradigm of sleep

Sleep continues to perplex scientists and researchers. Despite decades of sleep research, we still lack a clear understanding of the biological functions and evolution of sleep. In this review, we will examine sleep from a functional and phylogenetic perspective and describe some important conceptual gaps in understanding sleep. Classical theories of the biology and evolution of sleep emphasize sensory activation, energy balance, and metabolic homeostasis. Advances in electrophysiology, functional neuroimaging, and neuroplasticity allow us to view sleep within the framework of neural dynamics. With this paradigm shift, we have come to realize the importance of neurodynamic homeostasis in shaping the biology of sleep. Evidently, animals sleep to achieve neurodynamic and metabolic homeostasis. We are not aware of any framework for understanding sleep where neurodynamic, metabolic, homeostatic, chronophasic, and afferent variables are all taken into account. This motivated us to propose the two-mode three-drive (2m3d) paradigm of sleep. In the 2m3d paradigm, local neurodynamic/metabolic (N/M) processes switch between two modes-m0 and m1-in response to three drives-afferent, chronophasic, and homeostatic. The spatiotemporal integration of local m0/m1 operations gives rise to the global states of sleep and wakefulness. As a framework of evolution, the 2m3d paradigm allows us to view sleep as a robust adaptive strategy that evolved so animals can periodically reinforce neurodynamic and metabolic homeostasis while remaining sensitive to their internal and external environment.

Sleep and immunomodulatory responses to systemic lipopolysaccharide in mice selectively expressing interleukin-1 receptor 1 on neurons or astrocytes

Sleep-wake behavior is altered in response to immune challenge. Although the precise mechanisms that govern sickness-induced changes in sleep are not fully understood, interleukin-1β (IL-1) is one mediator of these responses. To better understand mechanisms underlying sleep and inflammatory responses to immune challenge, we used two transgenic mouse strains that express IL-1 receptor 1 (IL1R1) only in the central nervous system and selectively on neurons or astrocytes. Electroencephalographic recordings from transgenic and wild-type mice reveal that systemic challenge with lipopolysaccharide (LPS) fragments sleep, suppresses rapid eye movement sleep (REMS), increases non-REMS (NREMS), diminishes NREM delta power, and induces fever in all genotypes. However, the magnitude of REMS suppression is greater in mice expressing IL1R1 on astrocytes compared with mice in which IL1R1 is selectively expressed on neurons. Furthermore, there is a delayed increase in NREM delta power when IL1R1 is expressed on astrocytes. LPS-induced sleep fragmentation is reduced in mice expressing IL1R1 on neurons. Although LPS increases IL-1 and IL-6 in brain of all genotypes, this response is attenuated when IL1R1 is expressed selectively on neurons or on astrocytes. Collectively, these data suggest that in these transgenic mice under the conditions of this study it is neuronal IL1R1 that plays a greater role in LPS-induced suppression of REMS and NREM delta power, whereas astroglial IL1R1 is more important for sleep fragmentation after this immune challenge. Thus, aspects of central responses to LPS are modulated by IL1R1 in a cell type-specific manner.

Sleep and inflammatory markers in different psychiatric disorders

Many psychiatric disorders, like schizophrenia, affective disorders, addictions and different forms of dementia are associated with sleep disturbances. In the etiology and course of those diseases inflammatory processes are regarded to be an increasingly important factor. They are also a frequently discussed element of the pathology of sleep. In this literature review reports on correlations between poor sleep and inflammatory responses in various psychiatric conditions are discussed. The link between schizophrenia, affective disorders and inflammatory cytokines is a complex phenomenon, which has been already confirmed in a number of studies. However, the presence of sleep deficits in those conditions, being a common symptom of depression and psychoses, can be an additional factor having a considerable impact on the immunological processes in mental illnesses. In the analyzed data, a number of studies are presented describing the role of inflammatory markers in sleep disturbances and psychopathological symptoms of affective, psychotic, neurogenerative and other disorders. Also attention is drawn to possible implications for their treatment. Efforts to use, e.g., anti-inflammatory agents in psychiatry in the context of their impact on sleep are reported. The aspect of inflammatory markers in the role of sleep deprivation as the treatment method in major depressive disorder is also discussed. A general conclusion is drawn that the improvement of sleep quality plays a crucial role in the care for psychiatric patients.

Sleep restriction and delayed sleep associate with psychological health and biomarkers of stress and inflammation in women

STUDY OBJECTIVES

Despite strong associations between sleep duration and health, there is no clear understanding of how volitional chronic sleep restriction (CSR) alters the physiological processes that lead to poor health in women. We focused on biochemical and psychological factors that previous research suggests are essential to uncovering the role of sleep in health.

DESIGN

Cross-sectional study.

SETTING

University-based.

PARTICIPANTS

Sixty female participants (mean age, 19.3; SD, 2.1 years).

MEASUREMENTS

We analyzed the association between self-reported volitional CSR and time to go to sleep on a series of sleep and psychological health measures as well as biomarkers of immune functioning/inflammation (interleukin [IL]-1β), stress (cortisol), and sleep regulation (melatonin).

RESULTS

Across multiple measures, poor sleep was associated with decreased psychological health and a reduced perception of self-reported physical health. Volitional CSR was related to increased cortisol and increased IL-1β levels. We separately looked at individuals who experienced CSR with and without delayed sleep time and found that IL-1β levels were significantly elevated in CSR alone and in CSR combined with a late sleep time. Cortisol, however, was only elevated in those women who experienced CSR combined with a late sleep time. We did not observe any changes in melatonin across groups, and melatonin levels were not related to any sleep measures.

CONCLUSIONS

New to our study is the demonstration of how an increase in a proinflammatory process and an increase in hypothalamic-pituitary-adrenal axis activity both relate to volitional CSR, with and without a delayed sleep time. We further show how these mechanisms relate back to psychological and self-reported health in young adult women.

The bidirectional interactions between psoriasis and obstructive sleep apnea

Psoriasis is a chronic inflammatory skin disorder which can impair general routine activities and has been closely related to poor quality of life. Pruritus and scratching are frequently observed, occurring mainly during sleep and precipitating nighttime arousals. Indeed, sleep quality has been shown to be negatively affected in psoriatic patients, in a close relationship with stress exposure and immune response. Although psoriasis is known to impair sleep, leading to insomnia, its association with obstructive sleep apnea (OSA) is controversial. Similarly, OSA is considered a multifactorial inflammatory disease, characterized by intermittent hypoxia, sleep fragmentation and autonomic dysfunction, with important outcomes on the cardiovascular and metabolic systems. Importantly, immunological activities and pro-inflammatory cytokines play a prominent role in both OSA and psoriasis. Currently it is not clear whether OSA is a risk factor for psoriasis development or if psoriasis is a possible predictor of OSA. Thus, our main purpose is to provide an overview of this intriguing relationship and show the current link between psoriasis and OSA in a bidirectional relationship.

Sleep, Hansen's disease and the immune system--a not so harmonic triad

Hansen's disease is one of the oldest skin diseases in the world characterized by a spectrum of clinical manifestations that are associated with stigmatization and poor quality of life. It is also considered a model disease for investigating the human immune system because of its association with immune reactions, which are thought to be a reflection of the host's immunological response, promoting intense cellular activity or humoral secretion. This relationship between the cellular and microbial components of skin and their regulation by local immune responses may be modulated by a currently neglected behavior: sleep. Recent studies have demonstrated that sleep deprivation may aggravate the progression of chronic dermatological diseases, which in turn can lead to a non-restorative sleep pattern. Indeed, sleep is essential for immune and skin integrity. Thus, we propose here a hypothesis linking Hansen's disease, sleep and immunity in a bidirectional relationship. Hansen's disease patients may demonstrate a worse sleep quality than the general population through the modulation of immunological environment; and sleep restriction, a hallmark of modern society, being a possible predictor of the disease progression.

Using an innovative multiple regression procedure in a cancer population (Part II): fever, depressive affect, and mobility problems clarify an influential symptom pair (pain-fatigue/weakness) and cluster (pain-fatigue/weakness-sleep problems)

Background

Most patients with advanced cancer experience symptom pairs or clusters among pain, fatigue, and insomnia. However, only combinations where symptoms are mutually influential hold potential for identifying patient subgroups at greater risk, and in some contexts, interventions with “cross-over” (multisymptom) effects. Improved methods to detect and interpret interactions among symptoms, signs, or biomarkers are needed to reveal these influential pairs and clusters. I recently created sequential residual centering (SRC) to reduce multicollinearity in moderated regression, which enhances sensitivity to detect these interactions.

Methods

I applied SRC to moderated regressions of single-item symptoms that interact to predict outcomes from 268 palliative radiation outpatients. I investigated: 1) the hypothesis that the interaction, pain × fatigue/weakness × sleep problems, predicts depressive affect only when fever presents, and 2) an exploratory analysis, when fever is absent, that the interaction, pain × fatigue/weakness × sleep problems × depressive affect, predicts mobility problems. In the fever context, three-way interactions (and derivative terms) of the four symptoms (pain, fatigue/weakness, fever, sleep problems) are tested individually and simultaneously; in the non-fever context, a single four-way interaction (and derivative terms) is tested.

Results

Fever interacts separately with fatigue/weakness and sleep problems; these comoderators each magnify the pain–depressive affect relationship along the upper or full range of pain values. In non-fever contexts, fatigue/weakness, sleep problems, and depressive affect comagnify the relationship between pain and mobility problems.

Conclusion

Different mechanisms contribute to the pain × fatigue/weakness × sleep problems interaction, but all depend on the presence of fever, a sign/biomarker/symptom of proinflammatory sickness behavior. In non-fever contexts, depressive affect is no longer an outcome representing malaise from the physical symptoms of sickness, but becomes a fourth symptom of the interaction. In outpatient subgroups at heightened risk, single interventions could potentially relieve multiple symptoms when fever accompanies sickness malaise and in non-fever contexts with mobility problems. SRC strengthens insights into symptom pairs/clusters.

Using an innovative multiple regression procedure in a cancer population (Part 1): detecting and probing relationships of common interacting symptoms (pain, fatigue/weakness, sleep problems) as a strategy to discover influential symptom pairs and clusters

Background

The majority of patients with advanced cancer experience symptom pairs or clusters among pain, fatigue, and insomnia. Improved methods are needed to detect and interpret interactions among symptoms or diesease markers to reveal influential pairs or clusters. In prior work, I developed and validated sequential residual centering (SRC), a method that improves the sensitivity of multiple regression to detect interactions among predictors, by conditioning for multicollinearity (shared variation) among interactions and component predictors.

Materials and methods

Using a hypothetical three-way interaction among pain, fatigue, and sleep to predict depressive affect, I derive and explain SRC multiple regression. Subsequently, I estimate raw and SRC multiple regressions using real data for these symptoms from 268 palliative radiation outpatients.

Results

Unlike raw regression, SRC reveals that the three-way interaction (pain × fatigue/weakness × sleep problems) is statistically significant. In follow-up analyses, the relationship between pain and depressive affect is aggravated (magnified) within two partial ranges: 1) complete-to-some control over fatigue/weakness when there is complete control over sleep problems (ie, a subset of the pain–fatigue/weakness symptom pair), and 2) no control over fatigue/weakness when there is some-to-no control over sleep problems (ie, a subset of the pain–fatigue/weakness–sleep problems symptom cluster). Otherwise, the relationship weakens (buffering) as control over fatigue/weakness or sleep problems diminishes.

Conclusion

By reducing the standard error, SRC unmasks a three-way interaction comprising a symptom pair and cluster. Low-to-moderate levels of the moderator variable for fatigue/weakness magnify the relationship between pain and depressive affect. However, when the comoderator variable for sleep problems accompanies fatigue/weakness, only frequent or unrelenting levels of both symptoms magnify the relationship. These findings suggest that a countervailing mechanism involving depressive affect could account for the effectiveness of a cognitive behavioral intervention to reduce the severity of a pain, fatigue, and sleep disturbance cluster in a previous randomized trial.