Towards a unified model of neuroendocrine-immune interaction

IL-6 after wake-up in human males: Exposure to red versus blue light and the interplay with cortisol

Light is essential in shaping human circadian rhythms, including that of the hormone cortisol. While cortisol is known to influence secretion of the cytokine IL-6, the influence of light itself on IL-6 remains unclear. Thus, this study investigated the effects of two light conditions - red and blue - on IL-6 concentrations and the cortisol awakening response in blood. The interplay between cortisol and IL-6 was explored as well. The between-subject experiment was conducted with 71 healthy adult men (aged M red = 24.30, SD = 3.56; M blue = 24.40, SD = 3.51) in a standardized sleep laboratory setting with 60-min light exposure post-awakening at 05:00 a.m. Two mixed models, with light condition and time across measurement points as factors, were calculated. In the one for cortisol, chronotype was introduced as a covariate. Mean cortisol concentrations did not differ between exposure to red vs. blue light (p = 0.443), but overall cortisol output (area under the curve with respect to ground; AUCG) and sensitivity (area under the curve with respect to increase; AUCI) were greater in the blue-light condition (p = 0.050 and p < 0.001, respectively). Additionally, chronotype significantly influenced cortisol concentrations (p = 0.035). As for IL-6, a main effect of time was obtained, with increasing concentrations over time (p = 0.002). Total IL-6 secretion was greater under blue-light exposure (p <. 001), but mean IL-6 concentrations (p = 0.230) and IL-6 sensitivity (p = 0.777) did not differ between the red- and blue-light condition. Mean and total cortisol and IL-6 concentrations were significantly negatively correlated (p = 0.021 and p < 0.001, respectively) during the red-light exposure. In the blue-light condition, cortisol sensitivity was significantly negatively correlated with IL-6 sensitivity (p = 0.034). Overall, blue light seemed to have exerted a greater influence on cortisol and IL-6. For cortisol, this effect might be moderated by chronotype. Additionally, cortisol and IL-6 seem to interact under light exposure. However, these effects were mixed and could not be found consistently across mean secretion, AUCg and AUCi.

Possible roles of neuropeptide/transmitter and autoantibody modulation in emotional problems and aggression

The theoretical foundations of understanding psychiatric disorders are undergoing changes. Explaining behaviour and neuroendocrine cell communication leaning towards immunology represents a different approach compared to previous models for understanding complex central nervous system processes. One such approach is the study of immunoglobulins or autoantibodies, and their effect on peptide hormones in the neuro-endocrine system. In the present review, we provide an overview of the literature on neuropeptide/transmitter and autoantibody modulation in psychiatric disorders featuring emotional problems and aggression, including associated illness behaviour. Finally, we discuss the role of psycho-immunology as a growing field in the understanding of psychiatric disorders, and that modulation and regulation by IgG autoAbs represent a relatively new subcategory in psycho-immunology, where studies are currently being conducted.

Sleep and Immune System Crosstalk: Implications for Inflammatory Homeostasis and Disease Pathogenesis

Background

Sleep and immune function are interconnected aspects of health that mutually impact each other in disease development and inflammatory homeostasis. Different aspects of immunology are regulated by different sleep characteristics, impacting on specific aspects of immune function including cytokine production and T-cell activity. Ongoing disruptions of sleep have been linked to heightened inflammation and are suspected in the pathogenesis and disease course of a range of life-style-related illnesses, including diabetes and neurodegenerative diseases.

Summary

This review provides a comprehensive overview of knowledge on the interaction of sleep with the immune system, its modulation of inflammatory balance, and the pathogenesis of many diseases. It emphasizes how sleep deficiency compromises immune function by means of a systemic, low-grade inflammatory response, while adequate sleep promotes intense immune responses and thus enables efficient pathogen clearance and the maintenance of immune memory. The mutual influence of sleep on the immune system underlines its critical involvement in health preservation and the course of disease.

Key Message

Sleep plays an indispensable role in immune health, mediating the efficiency of immune responses and the course of the regulation of inflammation. Chronic sleep deprivation can result in a low-grade inflammation that substantially contributes to the onset and exacerbation of metabolic and neurodegenerative disorders. The intimate linkage between sleep and immune function can be one strategic approach to therapy, improving health outcomes by leveraging this sleep-immune connection.

Night shift work, sleep duration and endometrial cancer risk: A pooled analysis from the Epidemiology of Endometrial Cancer Consortium (E2C2)

Data on the role of circadian related factors in the etiology of endometrial cancer are scarce. We collected individual data on night shift work or daily sleep duration from 7,207 cases and 22,027 controls participating in 11 studies from the Epidemiology of Endometrial Cancer Consortium (E2C2). Main analyses were performed among postmenopausal women: 6,335 endometrial cancer cases and 18,453 controls. Using individual data, study-specific odd ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated with logistic regression and pooled analyses were conducted using random-effects meta-analyses. A non-significant inverse association was observed between endometrial cancer and night shift work (OR=0.89, 95%CI=0.72-1.09; I2=0.0%, Pheterogeneity=0.676). Associations did not vary by shift type (permanent or rotating), or duration of night work. Categorizations of short (<7h) or long (≥9h) sleep duration were not associated with endometrial cancer risk (ORshort=1.02, 95%CI=0.95-1.10; I2=55.3%, Pheterogeneity=0.022; ORlong=0.93, 95%CI=0.81-1.06; I2=11.5%, Pheterogeneity=0.339). No associations were observed per 1-h increment of sleep (OR=0.98, 95%CI=0.95-1.01; I2=46.1%, Pheterogeneity=0.063), but an inverse association was identified among obese women (OR=0.93, 95%CI=0.89-0.98 per 1-h increment; I2=12.7%, Pheterogeneity=0.329). Overall, these pooled analyses provide evidence that night shift work and sleep duration are not strong risk factors for endometrial cancer in postmenopausal women.

Physical activity and sleep relate to antibody maintenance following naturalistic infection and/or vaccination in older adults

Health behaviours such as being physically active and having good quality sleep have been associated with decreased susceptibility to infection and stronger antibody responses to vaccination. Less is known about how such factors might influence the maintenance of immunity following naturalistic infection and/or prior vaccination, particularly among older adults who may have formed initial antibodies some time ago. This analysis explored antibody levels against a range of common infectious diseases in 104 older adults (60 women) aged 65+ years, and whether these relate to self-reported physical activity (PA) and sleep. PA and sleep were measured subjectively through standardized questions. Antibody levels to a range of common pathogens, including pneumococcal (Pn) and meningococcal (Men) serotypes, Haemophilus influenza type b, diphtheria, and tetanus were assayed using Multiplex technology. Higher PA at baseline related to higher antibody levels against three Pn serotypes and MenY, and higher PA at one month with higher levels against six Pn serotypes. Longer time in bed related to higher antibody levels against Pn4, and longer sleep related to higher levels against Pn19f. More difficulty staying awake in the day related to lower antibodies against Pn19a, Pn19f, MenA and MenY, and more frequent daytime napping related to lower levels against three Pn serotypes and MenY. Using clinically protective antibody thresholds as an outcome showed similar results for PA, but effects for sleep became non-significant, with the exception of time in bed. This extends beyond existing literature demonstrating associations between PA and sleep and peak antibody response to vaccination to antibody maintenance. Longitudinal research with objective measures of health behaviours is warranted.

Stress and traumatic brain injury: An inherent bi-directional relationship with temporal and synergistic complexities

Traumatic brain injury (TBI) and stress are prevalent worldwide and can both result in life-altering health problems. While stress often occurs in the absence of TBI, TBI inherently involves some element of stress. Furthermore, because there is pathophysiological overlap between stress and TBI, it is likely that stress influences TBI outcomes. However, there are temporal complexities in this relationship (e.g., when the stress occurs) that have been understudied despite their potential importance. This paper begins by introducing TBI and stress and highlighting some of their possible synergistic mechanisms including inflammation, excitotoxicity, oxidative stress, hypothalamic-pituitary-adrenal axis dysregulation, and autonomic nervous system dysfunction. We next describe different temporal scenarios involving TBI and stress and review the available literature on this topic. In doing so we find initial evidence that in some contexts stress is a highly influential factor in TBI pathophysiology and recovery, and vice versa. We also identify important knowledge gaps and suggest future research avenues that will increase our understanding of this inherent bidirectional relationship and could one day result in improved patient care.

Potential effects of shift work on skin autoimmune diseases

Shift work is associated with systemic chronic inflammation, impaired host and tumor defense and dysregulated immune responses to harmless antigens such as allergens or auto-antigens. Thus, shift workers are at higher risk to develop a systemic autoimmune disease and circadian disruption with sleep impairment seem to be the key underlying mechanisms. Presumably, disturbances of the sleep-wake cycle also drive skin-specific autoimmune diseases, but epidemiological and experimental evidence so far is scarce. This review summarizes the effects of shift work, circadian misalignment, poor sleep, and the effect of potential hormonal mediators such as stress mediators or melatonin on skin barrier functions and on innate and adaptive skin immunity. Human studies as well as animal models were considered. We will also address advantages and potential pitfalls in animal models of shift work, and possible confounders that could drive skin autoimmune diseases in shift workers such as adverse lifestyle habits and psychosocial influences. Finally, we will outline feasible countermeasures that may reduce the risk of systemic and skin autoimmunity in shift workers, as well as treatment options and highlight outstanding questions that should be addressed in future studies.

Pro- and anti-inflammatory cytokines Interleukin-6 and Interleukin-10 predict therapy outcome of female patients with posttraumatic stress disorder

PTSD patients show alterations of the immune system, mainly a 'low-grade inflammation'. Psychotherapeutic treatments are meant to reduce symptom burden of PTSD patients but 30-50% of PTSD patients do not benefit from psychotherapy. Therefore, in this study, the predictive effect of cytokine levels on therapy outcome are investigated. Pro- (IL-6) and anti-inflammatory (IL-10) cytokines in female PTSD patients (N = 17) were assessed under acute stress during a Trier social stress test (TSST) before therapeutic treatment. The predictive effects of IL-6 and IL-10 on therapy outcome (SCL_GSI, BDI) after an inpatient psychotherapeutic treatment at the University Medical Center Carl Gustav Carus, Technische Universität Dresden was investigated. Areas under the curve with respect to ground (AUC_G) and increase (AUC_I) for IL-6 and IL-10 levels during the TSST were calculated and used as predictors in regression analyses with pre-treatment scores. Models including all three predictors show good model fits (R² = 0.255 to 0.744). Models including AUC_G and AUC_I scores show superior fits compared with models including pre-treatment scores alone (ΔR² = 0.196 to 0.444). IL-6 AUC_G and AUC_I scores are significant predictors for post-treatment SCL-GSI and BDI (β = -0.554 to 0.853), whereas IL-10 AUC_G significantly predicts SCL-GSI and BDI (β = -0.449 to -0.509). Therefore, pro- and anti-inflammatory IL-6 and IL-10 levels under acute stress before therapy predict therapy outcome of female PTSD patients regarding general symptom burden and depressive symptoms. Future studies should further address the link between inflammation and therapy outcome, especially underlying mechanisms and influencing factors.

Effect of Spore-Forming Probiotics on the Poultry Production: A Review

Due to the bad aspects associated with the use of antibiotics, the pressure on poultry production prompted the efforts to find out suitable growth-promoting and disease-preventing alternatives. Although many cost-effective alternatives have been developed, currently, one of the most auspicious alternatives for poultry feed is spore-forming probiotics, which can exert more beneficial effects as compared to normal probiotics, because of their ability to withstand the harsh external and internal conditions which result in increased viability. Many studies have already used spore-forming probiotics to improve different parameters of poultry production. Our laboratory has recently isolated a spore-forming bacterial strain, which has the potential to be used as a probiotic. So, to provide a detailed understanding, the current review aimed to collect valuable references to describe the mechanism of action of spore-forming probiotics and their effect on all the key aspects of poultry production.

The inflammatory immune system after wake up in healthy male individuals: A highly standardized and controlled study

This study investigates the effects of two light conditions on innate proinflammatory IL-6 cytokines and the cortisol awakening response. The between-subject experiment was conducted with 55 healthy adult-males (aged M bright = 24.40, SD = 4.58; M dim = 25.47, SD = 4.96) in a standardized sleep laboratory setting with 60-min light exposure post-awakening. Cortisol significantly increased with bright light exposure as compared to dim light (significant interaction effect). As for IL-6, the main effects of time and light condition were significant, however, the interaction effect between light and time was insignificant. Results replicate stimulatory effects of bright light on cortisol. In general, IL-6 concentrations decreased in both light conditions; however, bright light graphically showed higher concentrations 45-90 min after exposure in comparison to dim light, thus bright light has a potential stimulatory effect on IL-6 production.

Later sleep timing and social jetlag are related to increased inflammation in a population with a high proportion of OSA: findings from the Cleveland Family Study

STUDY OBJECTIVES

To examine the association between sleep midpoint and inflammation in a population with a large proportion of individuals diagnosed with obstructive sleep apnea syndrome (OSAS), a group that is already prone to increased inflammation.

METHODS

Subjects from the Cleveland Family Study underwent overnight polysomnography and completed surveys on sleep habits. Morning and evening blood samples were collected and assayed for proinflammatory biomarkers interleukin (IL)-1, IL-6, and tumor necrosis factor α (TNF-α). Linear regression models were used, adjusting for potential confounders and sleep duration.

RESULTS

The study population included 587 adults (52.3% with OSAS). Mean ± standard deviation weekday sleep midpoint was 3.52 ± 2.09 (3:31 am) and weekend sleep midpoint was 4.46 ± 1.69 (4:28 am). The Mean difference between weekday and weekend sleep midpoint (social jetlag) was 0.94 ± 2.08 hours. After adjusting for OSA severity, greater social jetlag was associated with higher levels of the inflammatory cytokine IL-1 (beta: 0.435 pg/mL, 95% confidence interval [CI]: 0.091 to 0.779). Additionally, later timing of sleep during both the weekdays and the weekends was associated with increased levels of IL-6 (weekday beta: 0.182 pg/mL; 95% CI: 0.013 to 0.350; and weekend beta: 0.188 pg/mL; 95% CI: 0.004 to 0.373). No trends were observed with TNF-α and any sleep exposure.

CONCLUSIONS

Later sleep timing was associated with elevated levels of IL-6 while increased social jetlag was associated with elevated levels of IL-1. Our results indicate that later sleep schedules and increased social jetlag may lead to higher inflammation, even after controlling for OSA severity.

CITATION

Girtman KL, Baylin A, O'Brien LM, Jansen EC. Later sleep timing and social jetlag are related to increased inflammation in a population with a high proportion of OSA: findings from the Cleveland Family Study. J Clin Sleep Med. 2022;18(9):2179-2187.

The Role of Chicken Prolactin, Growth Hormone and Their Receptors in the Immune System

Prolactin (PRL) and growth hormone (GH) exhibit important roles in the immune system maintenance. In poultry, PRL mainly plays its roles in nesting, hatching, and reproduction, while GH is primarily responding to body weight, fat formation and feed conversion. In this review, we attempt to provide a critical overview of the relationship between PRL and GH, PRLR and GHR, and the immune response of poultry. We also propose a hypothesis that PRL, GH and their receptors might be used by viruses as viral receptors. This may provide new insights into the pathogenesis of viral infection and host immune response.

Effects of prenatal opioid and alcohol exposures on immune and serotonin factors in human placenta

PURPOSE

Opioids and alcohol impact critical serotonin (5-HT) function in the developing placenta and fetus through the actions of immune proinflammatory factors. Yet, possible convergent effects of opioids and alcohol on human placental toll-like receptor 4 (TLR4) activation and subsequent 5-HT homeostasis remain entirely unknown. The purpose of this study was to examine the effect of prenatal exposure to opioids with or without prenatal alcohol exposure (PAE) on the expression of key placental immune and serotonin signaling factors in human placental tissue obtained from a well-characterized prospective cohort.

METHODS

Data were collected from a subset of participants enrolled in the prospective pre-birth Ethanol, Neurodevelopment, Infant, and Child Health (ENRICH-1) cohort. Women were recruited and classified into four study groups: 1) PAE (n = 20); 2) those taking medications for opioid use disorder (MOUD; n = 28), 3) concurrent PAE and MOUD (n = 20); and 4) controls (HC; n = 20) based on prospective, repeated self-report, and biomarker analysis. Placenta samples underwent tissue processing to identify mRNA for TLR4, nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), serotonin transporter (SERT), tryptophan hydroxylase (TPH1), indoleamine 2,3-Dioxygenase 1 (IDO) as well as protein concentrations of TLR4, IL-1β, TNF-α, SERT. To consider the association between study group and mRNA/protein expression of our targets, multivariable regression models were developed with inclusion of a priori selected covariates.

RESULTS

There was a significant negative association between PAE and SERT mRNA (β = -0.01; p < 0.01) and a positive association with TPH1 mRNA expression (β = 0.78; p < 0.05). In addition, there was a negative association between MOUD and TNF-α protein expression (β = -0.12; p < 0.05).

CONCLUSIONS

This study provides the first evidence that PAE may inhibit SERT expression while simultaneously promoting increased TPH1 protein expression in human placenta. This may result in increased 5-HT in fetal circulation known to affect neurodevelopment. Our data suggest that opioids and alcohol may disturb the bidirectional, dynamic interaction between the placental immune and serotonin system. Given the implication for brain development and health across the life-span further investigation of these critical mechanisms in well-defined cohorts is required.

Stress-induced pro- and anti-inflammatory cytokine concentrations in female PTSD and depressive patients

Alterations of the hypothalamus pituitary-axis on one hand and heightened rates of somatic diseases and mortality on the other hand are consistently found for PTSD and MDD patients. A possible link between these factors might be the immune system, in particular pro- and anti-inflammatory cytokines. A 'low-grade inflammation' in PTSD and MDD patients was found, whereas the influence of acute stress and the role of anti-inflammatory cytokines was rarely examined. In this study, 17 female PTSD patients participated in the Trier social stress test while serum cytokine levels (IL-6, IL-10) were assessed. Cytokine levels of PTSD patients were compared with levels of female depressive patients (n = 18) and female healthy controls (n = 18). Group differences were assessed using a 3 (group) x 8 (time: -15, -1, +1, +10, +20, +30, +45, +60 min) ANCOVA for repeated measures with baseline values as covariates. There was no group difference regarding IL-6 levels (p = 0.920) but PTSD patients showed significantly higher levels of IL-10 compared with depressive patients (p < 0.001, d = 0.16) and healthy controls (p = 0.001, d = 0.38). Under acute stress, PTSD patients did not show the widely found elevated IL-6 levels but showed an increase of anti-inflammatory IL-10. Therefore, acute stress seems to promote an imbalance of pro- and anti-inflammatory cytokine levels in PTSD and might indicate a hyperreactive immune response. This should be considered in future studies to further understand the role of the immune system as a link between stress response and somatic diseases.

The relationship between night shift work and breast cancer incidence: A systematic review and meta-analysis of observational studies

The purpose of this study was to investigate the relationship between night shift work and breast cancer (BC) incidence. A search was performed in PubMed, EBSCO, Web of Science, and Cochrane Library databases before June 2021. The exposure factor of this study is night shift work, the primary outcome is the risk of BC. A total of 33 observational studies composed of 4,331,782 participants were included. Night shift work increases the risk of BC in the female population (hazard ratio [HR] = 1.20, 95% confidence interval [Cl] = 1.10–1.31, p < 0.001), especially receptor-positive BC, including estrogen receptor (ER)+ BC (HR = 1.35, p < 0.001), progesterone receptor (PR)+ BC (HR = 1.30, p = 0.003), and human epidermal growth factor receptor 2 (HER2)+ BC (HR = 1.42, p < 0.001), but has no effect on HER2− BC (HR = 1.10, p = 0.515) and ER−/PR− BC (HR = 0.98, p = 0.827). The risk of BC was positively correlated with night shift working duration, frequency, and cumulative times. For women who start night work before menopause, night work will increase the incidence of BC (HR = 1.17, p = 0.020), but for women who start night work after menopause, night work does not affect BC (HR = 1.04, p = 0.293). Night work can increase the incidence of BC in the female population. The effect of long working hours, frequency, and the cumulative number of night shifts on BC is influenced by menopausal status.

Circadian rhythms and cancers: the intrinsic links and therapeutic potentials

The circadian rhythm is an evolutionarily conserved time-keeping system that comprises a wide variety of processes including sleep-wake cycles, eating-fasting cycles, and activity-rest cycles, coordinating the behavior and physiology of all organs for whole-body homeostasis. Acute disruption of circadian rhythm may lead to transient discomfort, whereas long-term irregular circadian rhythm will result in the dysfunction of the organism, therefore increasing the risks of numerous diseases especially cancers. Indeed, both epidemiological and experimental evidence has demonstrated the intrinsic link between dysregulated circadian rhythm and cancer. Accordingly, a rapidly increasing understanding of the molecular mechanisms of circadian rhythms is opening new options for cancer therapy, possibly by modulating the circadian clock. In this review, we first describe the general regulators of circadian rhythms and their functions on cancer. In addition, we provide insights into the mechanisms underlying how several types of disruption of the circadian rhythm (including sleep-wake, eating-fasting, and activity-rest) can drive cancer progression, which may expand our understanding of cancer development from the clock perspective. Moreover, we also summarize the potential applications of modulating circadian rhythms for cancer treatment, which may provide an optional therapeutic strategy for cancer patients.

The contribution of sleep to the neuroendocrine regulation of rhythms in human leukocyte traffic

Twenty-four-hour rhythms in immune parameters and functions are robustly observed phenomena in biomedicine. Here, we summarize the important role of sleep and associated parameters on the neuroendocrine regulation of rhythmic immune cell traffic to different compartments, with a focus on human leukocyte subsets. Blood counts of "stress leukocytes" such as neutrophils, natural killer cells, and highly differentiated cytotoxic T cells present a rhythm with a daytime peak. It is mediated by morning increases in epinephrine, leading to a mobilization of these cells out of the marginal pool into the circulation following a fast, beta2-adrenoceptor-dependent inhibition of adhesive integrin signaling. In contrast, other subsets such as eosinophils and less differentiated T cells are redirected out of the circulation during daytime. This is mediated by stimulation of the glucocorticoid receptor following morning increases in cortisol, which promotes CXCR4-driven leukocyte traffic, presumably to the bone marrow. Hence, these cells show highest numbers in blood at night when cortisol levels are lowest. Sleep adds to these rhythms by actively suppressing epinephrine and cortisol levels. In addition, sleep increases levels of immunosupportive mediators, such as aldosterone and growth hormone, which are assumed to promote T-cell homing to lymph nodes, thus facilitating the initiation of adaptive immune responses during sleep. Taken together, sleep-wake behavior with its unique neuroendocrine changes regulates human leukocyte traffic with overall immunosupportive effects during nocturnal sleep. In contrast, integrin de-activation and redistribution of certain leukocytes to the bone marrow during daytime activity presumably serves immune regulation and homeostasis.

A network meta-analysis of stress mediators in suicide behaviour

Stress homeostatic mediators are the most consistently anomalous biomarkers observed in suicide and may therefore point to a common 'core biology' of stress susceptibility, and suicidal behaviour. Previously reported meta-analyses have demonstrated aberrant levels of stress cortisol and inflammatory cytokines in suicide patients compared to controls, and significant associations between the stress regulator FK506-binding protein 51 (FKBP5) gene and suicidal behaviour. Although these independent studies were investigated as separate entities in suicide, stress mediators interact in a dynamic system, collectively giving rise to system changes physiologically, and ultimately psychologically and behaviourally. It is therefore important to study the dynamic network these stress mediators. Network meta-analysis allows for the simultaneous comparison of more than two biological mediators, and for comparisons to be made between mediators that have not been directly compared before, using previously reported, pooled meta data. Such network approaches may help study the complex biological phenomena of suicide and may provide better prediction of biological risk of suicidal states.

METHODS

This study aimed to establish the comparative relationships between key stress mediators in suicidal patients compared to non-suicidal controls using a random-effects network meta-analysis approach.. The key stress mediators included cortisol, six inflammatory markers (interleukin-6 (IL-6), interleukin-4 (IL-4), interleukin-2 (IL-2), tumour necrosis factor-a (TNF-α), interferon (IFN-y) and transforming growth factor β (TGF-β), and the FKBP5 single nucleotide polymorphism (SNP) allele. Data was derived from three previously published meta-analysis. The study population comprised of 1348 suicidal patients, defined as suicide attempters, completers, or patients with severe suicidal ideation, and 1750 non-suicidal controls, defined as healthy controls and psychiatric patients without suicidal ideation or previous attempts.

RESULTS

Pair-wise indirect effects of stress mediators in suicide compared to controls demonstrated that relative to the effect of the FKBP5 risk SNP allele on suicide risk, the magnitude of differences (suicide vs control) for the levels of IL-2 (SMD -0.72; 95% CI, -0.135 to -0.09 and IL-4 (SMD -0.71; 95% CI, -1.34 to -0.08) were significantly smaller (with 95% confidence intervals not crossing the null). The comparative relationships between stress mediators in suicidal behaviour demonstrates that the dynamic stress network relationship is dysregulated in suicide patients when compared to controls.

CONCLUSIONS

This model suggests that a genetic stress susceptibility with downstream abnormal cortisol stress axis functioning, together with anomalous interactions between the inflammatory system, may be one of the neurobiological correlates of suicide behaviour. This biological state may leave the individual physiologically susceptible and unable to cope with environmental stressors, which is consistent with the stress-diathesis hypothesis of suicide behaviour.

Does exposure to parasites modify relationships between diurnal cortisol and leukocytes among Honduran women?

BACKGROUND

Altered hypothalamic-pituitary-adrenal (HPA) function and related changes in circulating glucocorticoids have been implicated in the pathogenesis of numerous diseases that involve dysregulated immune function. Glucocorticoid hormones have both direct and indirect modulatory effects on both pro- and anti-inflammatory aspects of the immune system, including granulocytic and lymphocytic leukocyte subsets. However, past findings are complicated by inconsistencies across studies in how glucocorticoids and immune markers interact and relate to disease risk. Some incongruencies are likely due to an overreliance on single-unit (e.g., HPA or one immune marker) measures, and a failure to consider ecological exposures that may shape the base levels or correspondence between these systems. Here, we test single-unit and diurnal measures of HPA axis and immune system interactions in a less-industrial ecological setting with relatively high parasite loads.

METHODS

In a sample of 114 Honduran women (mean age = 36 years), morning and evening blood samples were analyzed to quantify granulocytes, lymphocytes, and immunoglobulin-E (IgE). Saliva was collected over 2 days (8 samples per woman) to measure peak cortisol, cumulative cortisol, and slope of decline. These repeated measures of saliva and venous blood were used to investigate associations between single-point and diurnal salivary cortisol and leukocytes, under variable levels of past parasite exposure (proxied by IgE).

RESULTS

Individuals with less of a decline in cortisol (i.e., "flatter" decline) show less of an increase in lymphocytes (2.27% increase in cells/μL/hr; 95% CI: 0.91-7.29; p = .01) across the day compared to those with steeper cortisol decline (7.5% increase in lymphocytes; 95% CI: 5.79-9.34; p < .001). IgE levels did not modify this association. Interestingly, IgE did moderate relationships between measures of cortisol and granulocytes: diurnal cortisol was positively associated with granulocytes, only in individuals with high previous exposure to parasites. There were no consistent relationships between single-unit measures of cortisol, lymphocytes or granulocytes, regardless of past parasite exposure.

DISCUSSION

Results demonstrate that the relationship between HPA function and immune modulation cannot be fully understood without an understanding of local disease ecology. These results highlight the importance of research that seeks to identify etiologies of disease across environmental contexts.

Mathematical Model Shows How Sleep May Affect Amyloid-β Fibrillization

Deposition of amyloid-β (Aβ) fibers in the extracellular matrix of the brain is a ubiquitous feature associated with several neurodegenerative disorders, especially Alzheimer's disease (AD). Although many of the biological aspects that contribute to the formation of Aβ plaques are well addressed at the intra- and intercellular levels in short timescales, an understanding of how Aβ fibrillization usually starts to dominate at a longer timescale despite the presence of mechanisms dedicated to Aβ clearance is still lacking. Furthermore, no existing mathematical model integrates the impact of diurnal neural activity as emanated from circadian regulation to predict disease progression due to a disruption in the sleep-wake cycle. In this study, we develop a minimal model of Aβ fibrillization to investigate the onset of AD over a long timescale. Our results suggest that the diseased state is a manifestation of a phase change of the system from soluble Aβ (sAβ) to fibrillar Aβ (fAβ) domination upon surpassing a threshold in the production rate of sAβ. By incorporating the circadian rhythm into our model, we reveal that fAβ accumulation is crucially dependent on the regulation of the sleep-wake cycle, thereby indicating the importance of good sleep hygiene in averting AD onset. We also discuss potential intervention schemes to reduce fAβ accumulation in the brain by modification of the critical sAβ production rate.

Differences in Diurnal Variation of Immune Responses in Microglia and Macrophages: Review and Perspectives

Biological rhythms, especially those that last close to 24 h, better known as circadian rhythms, are highly regulated phenomena, maintained throughout evolution in various organisms which allow organisms to predict, prepare for, and adapt to environmental changes. One of these phenomena that exhibit biological rhythms is the immune response to external agents. Immune cells (neutrophils, lymphocytes, macrophages, among others), as well as their mediators such as cytokines and chemokines, undergo variations in tissue and blood concentrations during the day. These rhythms are still being elucidated in microglia, the resident macrophages of the central nervous system, but since these cells share a common origin with peripheral macrophages, they are expected to behave similarly. In this review, we will discuss the possible differences in the responses between peripheral macrophages and microglia, their relationship with the circadian clock, and whether these rhythms can influence therapeutic choices.

Network between Cytokines, Cortisol and Occupational Stress in Gas and Oilfield Workers

To test whether gas and oil field work is accompanied by stress and altered immune function, the perception of workplace stress, levels of salivary cortisol, plasma levels, and mononuclear cell production of cytokines were examined in 80 healthy workers recruited among a population of operators on gas and oilfields. Specific questionnaires for determining the perception of anxiety, occupational stress, and subjective symptoms were administered. Salivary cortisol and cytokines plasma levels were evaluated by Elisa and to investigate immune function, both spontaneous and PHA- or LPS-induced expression and production of cytokines were assessed by qRT-PCR. Workers showed medium stress levels at work, with growth and increased motivation for work, and based on salivary cortisol concentrations, were divided into two groups of ≤10 ng/mL (n = 31) or >10 ng/mL (n = 49). Statistically significant higher plasma levels of IL-6, while lower TNFα, were detected in workers with cortisol >10 ng/mL. Also, BMI, DL, JD and Job strain were significantly higher in workers with cortisol >10 ng/mL. Thus, even modest variations of cortisol might have a role in the modulation of immune response and worker’s vulnerability to health imbalance.Thus, the evaluation of immune status, in addition to cortisol levels, could be useful to prevent illnesses; exacerbation of pre-existing conditions; morbidity; and consequent absences from work, with economic repercussions.

The Sleep-Immune Crosstalk in Health and Disease

Sleep and immunity are bidirectionally linked. Immune system activation alters sleep, and sleep in turn affects the innate and adaptive arm of our body's defense system. Stimulation of the immune system by microbial challenges triggers an inflammatory response, which, depending on its magnitude and time course, can induce an increase in sleep duration and intensity, but also a disruption of sleep. Enhancement of sleep during an infection is assumed to feedback to the immune system to promote host defense. Indeed, sleep affects various immune parameters, is associated with a reduced infection risk, and can improve infection outcome and vaccination responses. The induction of a hormonal constellation that supports immune functions is one likely mechanism underlying the immune-supporting effects of sleep. In the absence of an infectious challenge, sleep appears to promote inflammatory homeostasis through effects on several inflammatory mediators, such as cytokines. This notion is supported by findings that prolonged sleep deficiency (e.g., short sleep duration, sleep disturbance) can lead to chronic, systemic low-grade inflammation and is associated with various diseases that have an inflammatory component, like diabetes, atherosclerosis, and neurodegeneration. Here, we review available data on this regulatory sleep-immune crosstalk, point out methodological challenges, and suggest questions open for future research.

Biomarkers as Common Data Elements for Symptom and Self-Management Science

PURPOSE

Biomarkers as common data elements (CDEs) are important for the characterization of biobehavioral symptoms given that once a biologic moderator or mediator is identified, biologically based strategies can be investigated for treatment efforts. Just as a symptom inventory reflects a symptom experience, a biomarker is an indicator of the symptom, though not the symptom per se. The purposes of this position paper are to (a) identify a "minimum set" of biomarkers for consideration as CDEs in symptom and self-management science, specifically biochemical biomarkers; (b) evaluate the benefits and limitations of such a limited array of biomarkers with implications for symptom science; (c) propose a strategy for the collection of the endorsed minimum set of biologic samples to be employed as CDEs for symptom science; and (d) conceptualize this minimum set of biomarkers consistent with National Institute of Nursing Research (NINR) symptoms of fatigue, depression, cognition, pain, and sleep disturbance.

DESIGN AND METHODS

From May 2016 through January 2017, a working group consisting of a subset of the Directors of the NINR Centers of Excellence funded by P20 or P30 mechanisms and NINR staff met bimonthly via telephone to develop this position paper suggesting the addition of biomarkers as CDEs. The full group of Directors reviewed drafts, provided critiques and suggestions, recommended the minimum set of biomarkers, and approved the completed document. Best practices for selecting, identifying, and using biological CDEs as well as challenges to the use of biological CDEs for symptom and self-management science are described. Current platforms for sample outcome sharing are presented. Finally, biological CDEs for symptom and self-management science are proposed along with implications for future research and use of CDEs in these areas.

FINDINGS

The recommended minimum set of biomarker CDEs include pro- and anti-inflammatory cytokines, a hypothalamic-pituitary-adrenal axis marker, cortisol, the neuropeptide brain-derived neurotrophic factor, and DNA polymorphisms.

CONCLUSIONS

It is anticipated that this minimum set of biomarker CDEs will be refined as knowledge regarding biologic mechanisms underlying symptom and self-management science further develop. The incorporation of biological CDEs may provide insights into mechanisms of symptoms, effectiveness of proposed interventions, and applicability of chosen theoretical frameworks. Similarly, as for the previously suggested NINR CDEs for behavioral symptoms and self-management of chronic conditions, biological CDEs offer the potential for collaborative efforts that will strengthen symptom and self-management science.

CLINICAL RELEVANCE

The use of biomarker CDEs in biobehavioral symptoms research will facilitate the reproducibility and generalizability of research findings and benefit symptom and self-management science.

The physiological constellation of deprivation: Immunological strategies and health outcomes

Physiology and behavior are best thought of as two aspects of the same biological process, shaped simultaneously by natural selection. Like behavioral strategies, ecological conditions may affect physiological strategies, leading to changes in immunity and hormonal regulation. These alternate strategies help explain the health correlations of deprivation and provide additional pathways for feedback from early-life experiences.

Sleep Health Promotion: Practical Information for Physical Therapists

Sleep disturbances occur in one third of the US population, and the Centers for Disease Control and Prevention's National Center for Injury Prevention and Control has deemed insufficient sleep to be a public health problem. Knowledge about sleep and skills to screen sleep disorders and to promote sleep health have been recommended for physical therapists. Furthermore, in survey studies, physical therapists overwhelmingly agree that sleep is important for health and poor sleep impairs function. Sleep is critical for the proper functioning of the body, including immune function, tissue healing, pain modulation, cardiovascular health, cognitive function, and learning and memory. Sleep disruptions occur across the life span and in individuals with various conditions that are typically treated by physical therapists. Therefore, the purpose of this perspective paper is to (1) discuss the relevance of sleep to physical therapist practice, (2) recommend tools to screen for the 3 most common sleep disorders, and (3) provide suggestions for how therapists can integrate sleep health in prevention, health promotion, and wellness interventions.

The immunomodulatory role of the hypothalamus-pituitary-gonad axis: Proximate mechanism for reproduction-immune trade offs?

The present review discusses the communication between the hypothalamic-pituitary-gonad (HPG) axis and the immune system of vertebrates, attempting to situate the HPG-immune interaction into the context of life history trade-offs between reproductive and immune functions. More specifically, (i) we review molecular and cellular interactions between hormones of the HPG axis, and, as far as known, the involved mechanisms on immune functions, (ii) we evaluate whether the HPG-immune crosstalk serves as proximate mechanism mediating reproductive-immune trade-offs, and (iii) we ask whether the nature of the HPG-immune interaction is conserved throughout vertebrate evolution, despite the changes in immune functions, reproductive modes, and life histories. In all vertebrate classes studied so far, HPG hormones have immunomodulatory functions, and indications exist that they contribute to reproduction-immunity resource trade-offs, although the very limited information available for most non-mammalian vertebrates makes it difficult to judge how comparable or different the interactions are. There is good evidence that the HPG-immune crosstalk is part of the proximate mechanisms underlying the reproductive-immune trade-offs of vertebrates, but it is only one factor in a complex network of factors and processes. The fact that the HPG-immune interaction is flexible and can adapt to the functional and physiological requirements of specific life histories. Moreover, the assumption of a relatively fixed pattern of HPG influence on immune functions, with, for example, androgens always leading to immunosuppression and estrogens always being immunoprotective, is probably oversimplified, but the HPG-immune interaction can vary depending on the physiological and envoironmental context. Finally, the HPG-immune interaction is not only driven by resource trade-offs, but additional factors such as, for instance, the evolution of viviparity shape this neuroendocrine-immune relationship.

Neuroendocrine-immune circuits, phenotypes, and interactions

Multidirectional interactions among the immune, endocrine, and nervous systems have been demonstrated in humans and non-human animal models for many decades by the biomedical community, but ecological and evolutionary perspectives are lacking. Neuroendocrine-immune interactions can be conceptualized using a series of feedback loops, which culminate into distinct neuroendocrine-immune phenotypes. Behavior can exert profound influences on these phenotypes, which can in turn reciprocally modulate behavior. For example, the behavioral aspects of reproduction, including courtship, aggression, mate selection and parental behaviors can impinge upon neuroendocrine-immune interactions. One classic example is the immunocompetence handicap hypothesis (ICHH), which proposes that steroid hormones act as mediators of traits important for female choice while suppressing the immune system. Reciprocally, neuroendocrine-immune pathways can promote the development of altered behavioral states, such as sickness behavior. Understanding the energetic signals that mediate neuroendocrine-immune crosstalk is an active area of research. Although the field of psychoneuroimmunology (PNI) has begun to explore this crosstalk from a biomedical standpoint, the neuroendocrine-immune-behavior nexus has been relatively underappreciated in comparative species. The field of ecoimmunology, while traditionally emphasizing the study of non-model systems from an ecological evolutionary perspective, often under natural conditions, has focused less on the physiological mechanisms underlying behavioral responses. This review summarizes neuroendocrine-immune interactions using a comparative framework to understand the ecological and evolutionary forces that shape these complex physiological interactions.

Distribution and Cellular Heterogeneity of Bovine Viral Diarrhea Viral Antigen Expression in the Brain of Persistently Infected Calves: A New Perspective

Persistent infection following in utero exposure to bovine viral diarrhea virus (BVDV) early in gestation is a serious cause of morbidity and mortality in cattle industries worldwide. The brain is a primary target of persistent infection. In the current study, the types of cells infected and topography of viral antigen expression were examined in brain sections from 9 BVDV persistently infected crossbred calves, all less than 1 year of age, by immunohistochemical staining using the 15C5 primary monoclonal antibody. BVDV antigen was detected in the brains of all persistently infected calves. A variety of cell types was infected, including neurons, astrocytes, oligodendroglia, blood vessel-associated cells (pericytes, perivascular macrophages, smooth muscle cells), and cells in the leptomeninges (blood vessel-associated cells). Conclusive demonstration of viral antigen in vascular endothelial cells was elusive. The intensity and distribution of viral antigen staining in neurons were highly variable. Viral antigen staining was most consistent and intense in thalamic nuclei, most notably in dorsal and medial nuclear groups, followed by the hippocampus, entorhinal cortex, basal nuclei, and piriform cortex. Staining in other brain areas was often less intense and inconsistent. The variability in the intensity and topography of viral antigen in the brain may explain the heterogeneity in the clinical manifestations of BVDV-induced disease. Additionally, infection of the brain in persistently infected calves may underlie or at least contribute to endocrine disturbances and immunologic deficits that are protean manifestations of BVDV-induced disease.

Relationships between inflammatory cytokine and cortisol responses in firefighters exposed to simulated wildfire suppression work and sleep restriction

The interplay between inflammatory and cortisol responses modulates an appropriate response to a stressor. Exposure to severe stressors, however, may alter the actions and relationships of these responses and contribute to negative health outcomes. Physical work and sleep restriction are two stressors faced by wildland firefighters, yet their influence on the relationship between inflammatory and cortisol responses is unknown. The aim of the present study was to quantify the relationship between the cytokine and cortisol responses to sleep restriction while performing simulated physical wildfire suppression work. Firefighters completed 3 days of simulated physical firefighting work separated by either an 8-h (Control condition; n = 18) or 4-h sleep (Sleep restriction condition; n = 17) opportunity on each of the two nights. Salivary cortisol and inflammatory cytokines (IL-6, IL-8, IL-1β, TNF-α, IL-4, and IL-10) were measured throughout each day. An increase in morning IL-6 was related to a rise (6.2%, P = 0.043) in evening cortisol among firefighters in the sleep restriction condition. Higher morning IL-6 levels were related to increased (5.3%, P = 0.048) daily cortisol levels, but this relationship was not different between conditions. Less pronounced relationships were demonstrated between TNF-α, IL-10, IL-4, and cortisol independent of the sleep opportunity, but relationships did not persist after adjusting for demographic factors and other cytokines. These findings quantify the relationship between cytokine and cortisol responses among wildland firefighters exposed to simulated occupational stressors. Potential disturbances to the IL-6 and cortisol relationship among sleep-restricted firefighters’ supports further investigations into the negative health effects related to possible imbalances between these systems.

Bidirectional psychoneuroimmune interactions in the early postpartum period influence risk of postpartum depression

More than 500,000 U.S. women develop postpartum depression (PPD) annually. Although psychosocial risks are known, the underlying biology remains unclear. Dysregulation of the immune inflammatory response and the hypothalamic-pituitary-adrenal (HPA) axis are associated with depression in other populations. While significant research on the contribution of these systems to the development of PPD has been conducted, results have been inconclusive. This is partly because few studies have focused on whether disruption in the bidirectional and dynamic interaction between the inflammatory response and the HPA axis together influence PPD. In this study, we tested the hypothesis that disruption in the inflammatory-HPA axis bidirectional relationship would increase the risk of PPD. Plasma pro- and anti-inflammatory cytokines were measured in women during the 3rd trimester of pregnancy and on Days 7 and 14, and Months 1, 2, 3, and 6 after childbirth. Saliva was collected 5 times the day preceding blood draws for determination of cortisol area under the curve (AUC) and depressive symptoms were measured using the Edinburgh Postpartum Depression Survey (EPDS). Of the 152 women who completed the EPDS, 18% were depressed according to EDPS criteria within the 6months postpartum. Cortisol AUC was higher in symptomatic women on Day 14 (p=.017). To consider the combined effects of cytokines and cortisol on predicting symptoms of PPD, a multiple logistic regression model was developed that included predictors identified in bivariate analyses to have an effect on depressive symptoms. Results indicated that family history of depression, day 14 cortisol AUC, and the day 14 IL8/IL10 ratio were significant predictors of PPD symptoms. One unit increase each in the IL8/IL10 ratio and cortisol AUC resulted in 1.50 (p=0.06) and 2.16 (p=0.02) fold increases respectively in the development of PPD. Overall, this model correctly classified 84.2% of individuals in their respective groups. Findings suggest that variability in the complex interaction between the inflammatory response and the HPA axis influence the risk of PPD.

Differential acute effects of sleep on spontaneous and stimulated production of tumor necrosis factor in men

Tumor necrosis factor (TNF) is considered a key molecule in the regulation of sleep in health and disease. Conversely, sleep compared to sleep deprivation can modulate TNF release, but overall results are conflicting. In this study we focused on the influence of sleep on spontaneous, i.e., unstimulated TNF production, which might be involved in sleep regulation under normal non-infectious conditions, and on lipopolysaccharide (LPS)-stimulated TNF production, which reflects the capacity of the immune system to respond to a pathogen. To this end, we monitored 10 healthy men during a regular sleep-wake cycle and during 24h of wakefulness while blood was sampled repeatedly to analyze circulating TNF levels in serum as well as intracellular TNF production in monocytes spontaneously and after stimulation with LPS employing whole blood cell cultures. In addition we assessed numbers of monocyte subsets and levels of various hormones in blood. In comparison with nocturnal wakefulness, sleep acutely decreased serum TNF levels, with no parallel decrease in spontaneous monocytic TNF production, but was associated with a striking nighttime increase in the percentage of TNF producing monocytes after stimulation with LPS. The following day circulating TNF showed a reverse pattern with higher levels after regular sleep than after the nocturnal vigil. The mechanisms mediating the differential effects of sleep on circulating TNF (acutely decreased) vs. stimulated monocytic TNF production (acutely increased) remain unclear, although explorative correlational analyses pointed to a regulatory involvement of cortisol, norepinephrine and prolactin. The acute enhancing effect of sleep on LPS stimulated monocytic TNF production adds to the notion that nocturnal sleep favors immune defense to a microbial challenge.

Adrenal steroids modulate the immune response during Brucella abortus infection by a mechanism that depends on the regulation of cytokine production

Human brucellosis is a protean disease with a diversity of clinical signs and symptoms resulting from infection with Brucella species. Recent reports suggest a cross-regulation between adrenal steroids (cortisol and dehydroepiandrosterone [DHEA]) and the immune system. Monocytes and macrophages are the main replication niche for Brucella. Therefore, we investigated the role of adrenal hormones on the modulation of the immune response mediated by macrophages in B. abortus infection. Cortisol treatment during B. abortus infection significantly inhibits cytokine, chemokine, and MMP-9 secretion. In contrast, DHEA treatment had no effect. However, DHEA treatment increases the expression of costimulatory molecules (CD40, CD86), the adhesion molecule CD54, and major histocompatibility complex class I (MHC-I) and MHC-II expression on the surface of B. abortus-infected monocytes. It is known that B. abortus infection inhibits MHC-I and MHC-II expression induced by gamma interferon (IFN-γ) treatment. DHEA reverses B. abortus downmodulation of the MHC-I and -II expression induced by IFN-γ. Taken together, our data indicate that DHEA immune intervention may positively affect monocyte activity during B. abortus infection.

Altered IL-2, IL-6 and IL-8 serum levels in schizophrenia patients with tardive dyskinesia

Immune deregulation has been postulated to be one of the mechanisms underlying the pathogenesis of tardive dyskinesia (TD). We hypothesized that interleukins would have a link with TD in schizophrenia patients. In this study, the serum IL-2, IL-6 and IL-8 levels were examined by enzyme-linked immunosorbent assay (ELISA) in schizophrenia patients with TD (n=48) and without TD (n=45), and healthy controls (n=44). The psychopathological symptoms of schizophrenia were assessed by the Positive and Negative Syndrome Scale (PANSS). The severity of TD was evaluated using Abnormal Involuntary Movement Scale (AIMS). The results showed that serum IL-2, IL-6 and IL-8 levels were significantly different among schizophrenia patients with TD and without TD and normal controls. Moreover, IL-2 level was significantly correlated with PANSS positive subscale and general subscale in patients with TD and without TD. In addition, IL-2 level was positively correlated with AIMS score in TD patients. The results supported that immune disturbance is related to the schizophrenia patients, especially to the patients with TD and ILs might play an important role in the pathophysiology of schizophrenia patients with TD.

Ocular Mucosal Immunity

Mucosal immunity defends the ocular surface against antigenic challenge and microbial invasion. The principal effector site is the lacrimal gland, where immunoglobulin A (IgA) antibodies are produced. Nasal-associated lymphoid tissue and posterior cervical lymph nodes function as major inductive sites for tear IgA responses. Neural connections and systemic hormones maintain the integrity and function of the ocular surface. Neuroenzyme activities in the lacrimal gland are influenced by ocular infections, leading to reduced expression of acetylcholine and modulation of receptors on acinar cells and on plasma cells, thereby decreasing fluid and immunoglobulin secretion. T lymphocyte-dependent responses result in production of interleukin-4 in lacrimal glands, thereby influencing cholinergic enzyme activity affecting immune processes and lacrimal physiology. Furthermore, neuropeptides released into lymphoid structures or inflamed tissues are chemotactic for antigen-presenting cells and affect their interactions with T cells. Thus, in developing therapeutic approaches for treating dry-eye conditions and vaccination strategies to elicit protective ocular mucosal immune responses, the entire lacrimal functional unit should be considered.

Rheumatoid arthritis and the biological clock

Rheumatoid arthritis (RA) is an autoimmune disease of unknown cause and a chronic and progressive inflammatory disorder ensuing in genetically predisposed subjects, characterized by synovitis causing joint destruction, as well as inflammation in body organ systems, leading to anatomical alteration and functional disability. Immune competent cells, deregulated synoviocytes and cytokines play a key role in the pathophysiological mechanisms. The immune system function shows time-related variations related to the influence of the neuroendocrine system and driven by the circadian clock circuitry. Immune processes and symptom intensity in RA are characterized by oscillations during the day following a pattern of circadian rhythmicity. A cross-talk between inflammatory and circadian pathways is involved in RA pathogenesis and underlies the mutual actions of disruption of the circadian clock circuitry on immune system function as well as of inflammation on the function of the biological clock. Modulation of molecular processes and humoral factors mediating in RA the interplay between the biological clock and the immune response and underlying the rhythmic fluctuations of pathogenic processes and symptomatology could represent a promising therapeutic strategy in the future.

Increased plasma level of tumor necrosis factor α in patients with narcolepsy in Taiwan

BACKGROUND

Narcolepsy is a neuropsychiatric disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and abnormal rapid eye movement (REM) sleep. Tumor necrosis factor α (TNF α) and its cognate receptors have been reported to be involved in the pathophysiology of narcolepsy in addition to the HLA antigen system. Our study aimed to determine if the TNF-α system was associated with narcolepsy in our patients.

METHODS

We first measured the plasma level of TNF α in 56 narcoleptic patients and 53 control subjects using a highly sensitive enzyme-linked immunosorbent assay. We next determined the genotype of three single nucleotide polymorphisms (SNPs) (T-1031C, C-863A, and C-857T) at the promoter region of the TNF-α gene and one missense SNP (T587G, M196R) at the exon 6 of the tumor necrosis factor receptor 2 gene, TNFR2, in a sample of 75 narcoleptic patients and 201 control subjects by direct sequencing analysis.

RESULTS

We found a significant elevation of plasma level of TNF α in patients with narcolepsy compared with the control subjects (4.64pg/mL vs 1.06pg/mL; P=.0013). However, we did not find significant differences between these two groups in the allelic and genotypic distributions of the investigated polymorphisms.

CONCLUSIONS

Our study suggests that an increased TNF-α level was associated with narcolepsy in our patients, and that chronic inflammation due to various factors might have led to the increased TNF-α levels found in our patients.

The involvement of PDGF/VEGF related factor in regulation of immune and neuroendocrine in Chinese mitten crab Eriocheir sinensis

Members of the platelet-derived growth factor/vascular endothelial growth factor (PDGF/VEGF) family have been implicated in cell proliferation, cell differentiation, and cell migration, vascular development, angiogenesis and neural development. In the present study, a novel PDGF/VEGF related factor gene was cloned and identified in Chinese mitten crab Eriocheir sinensis (designated as EsPVF1). The full-length cDNA of EsPVF1 was of 1173 bp, consisting a 5' untranslated region (UTR) of 54 bp, a 3' UTR of 1131 bp with a poly (A) tail, and an open reading frame (ORF) of 588 bp encoding 196 amino acid residues. A signal peptide of 20 amino acid residues, a PDGF/VEGF homology growth factor domain of 81 amino acids, and a typical cysteine knot motif (CXCXC) were identified in the deduced amino acid sequence of EsPVF1. By fluorescent quantitative real-time PCR, the EsPVF1 mRNA was detected ubiquitously in the select tissues of hemocytes, gonad, heart, muscle, hepatopancreas and gill, with the high abundance in hemocytes and gonad. The mRNA expression level of EsPVF1 was up-regulated and reached the highest at 24 h after Vibrio anguillarum challenge, while it was induced at 3 h, 6 h, 12 h, 24 h and 48 h compared with the untreated group after Pichia pastoris GS115 challenge. Tissue injury also induced the mRNA expression of EsPVF1 in hemocytes of crabs, and the expression level increased obviously at 8 h. The cDNA fragment encoding mature peptide of EsPVF1 was recombined and expressed in Escherichia coli BL21 (DE3) pLysS. Biogenic amine in hemolymph pre-incubated with recombinant protein of EsPVF1 (rEsPVF1) was detected by fluorimetric method. Norepinephrine and dopamine in hemolymph incubated with rEsPVF1 were higher than that in the blank group. Therefore, EsPVF1 could significantly provoke the release of norepinephrine and dopamine. The results collectively indicated that EsPVF1 was involved in regulation of the immune response and neuroendocrine system in crabs.

Effects of Cortisol Administered through Slow-Release Implants on Innate Immune Responses in Rainbow Trout (Oncorhynchus mykiss)

Cortisol is a key hormone in the fish stress response with a well-known ability to regulate several physiological functions, including energy metabolism and the immune system. However, data concerning cortisol effects on fish innate immune system using a more controlled increase in cortisol levels isolated from any other stress related signaling is scarce. The present study describes the effect of doses of cortisol corresponding to acute and chronic levels on the complement and lysozyme activity in plasma of the rainbow trout (Oncorhynchus mykiss). We also evaluated the effects of these cortisol levels (from intraperitoneally implanted hydrocortisone) on the mRNA levels quantified by RT-qPCR of selected key immune-related genes in the liver, head kidney, and spleen. For that purpose, 60 specimens of rainbow trout were divided in to two groups: a control group injected with a coconut oil implant and another group injected with the same implant and cortisol (50 μg cortisol/g body weight). Our results demonstrate the role of cortisol as a modulator of the innate immune response without the direct contribution of other stress axes. Our results also show a relationship between the complement and lysozyme activity in plasma and mRNA levels in liver, supporting the important role of this organ in producing these immune system proteins after a rise of cortisol in the fish plasma.

Human immune deficiency virus (HIV) infection and the hypothalamic pituitary adrenal axis

The hypothalamic pituitary adrenal (HPA) axis is the most common of the endocrine lines/axis' to be affected by HIV infection. There are multiple factors that contribute to this HPA axis dysregulation. Direct invasion of the various organs in the axis can be either by opportunistic infections or infiltrative diseases. The soluble factors or cytokines released during viral infection and the chronic inflammatory state that follows, also contribute to these alterations. The actions of these cytokines released by the immune response can both activate the HPA axis and cause a glucocorticoid resistant state. Further, many of the anti-retroviral and other medications used to treat HIV infection can contribute to HPA axis dysfunction. While the diagnosis and treatment of endocrine dysfunction is the same as in any other patient, management pathways may be quite different. While some may be adaptive responses, life threatening adrenal insufficiency can also be present. It is important the latter be picked up expeditiously and treated promptly to avoid mortality.

Crosstalk between the circadian clock circuitry and the immune system

Various features, components, and functions of the immune system present daily variations. Immunocompetent cell counts and cytokine levels present variations according to the time of day and the sleep-wake cycle. Moreover, different immune cell types, such as macrophages, natural killer cells, and lymphocytes, contain a circadian molecular clockwork. The biological clocks intrinsic to immune cells and lymphoid organs, together with inputs from the central pacemaker of the suprachiasmatic nuclei via humoral and neural pathways, regulate the function of cells of the immune system, including their response to signals and their effector functions. Consequences of this include, for example, the daily variation in the response to an immune challenge (e.g., bacterial endotoxin injection) and the circadian control of allergic reactions. The circadian-immune connection is bidirectional, because in addition to this circadian control of immune functions, immune challenges and immune mediators (e.g., cytokines) were shown to have strong effects on circadian rhythms at the molecular, cellular, and behavioral levels. This tight crosstalk between the circadian and immune systems has wide-ranging implications for disease, as shown by the higher incidence of cancer and the exacerbation of autoimmune symptoms upon circadian disruption.

Astakine 2--the dark knight linking melatonin to circadian regulation in crustaceans

Daily, circadian rhythms influence essentially all living organisms and affect many physiological processes from sleep and nutrition to immunity. This ability to respond to environmental daily rhythms has been conserved along evolution, and it is found among species from bacteria to mammals. The hematopoietic process of the crayfish Pacifastacus leniusculus is under circadian control and is tightly regulated by astakines, a new family of cytokines sharing a prokineticin (PROK) domain. The expression of AST1 and AST2 are light-dependent, and this suggests an evolutionarily conserved function for PROK domain proteins in mediating circadian rhythms. Vertebrate PROKs are transmitters of circadian rhythms of the suprachiasmatic nucleus (SCN) in the brain of mammals, but the mechanism by which they function is unknown. Here we demonstrate that high AST2 expression is induced by melatonin in the brain. We identify RACK1 as a binding protein of AST2 and further provide evidence that a complex between AST2 and RACK1 functions as a negative-feedback regulator of the circadian clock. By DNA mobility shift assay, we showed that the AST2-RACK1 complex will interfere with the binding between BMAL1 and CLK and inhibit the E-box binding activity of the complex BMAL1-CLK. Finally, we demonstrate by gene knockdown that AST2 is necessary for melatonin-induced inhibition of the complex formation between BMAL1 and CLK during the dark period. In summary, we provide evidence that melatonin regulates AST2 expression and thereby affects the core clock of the crustacean brain. This process may be very important in all animals that have AST2 molecules, i.e. spiders, ticks, crustaceans, scorpions, several insect groups such as Hymenoptera, Hemiptera, and Blattodea, but not Diptera and Coleoptera. Our findings further reveal an ancient evolutionary role for the prokineticin superfamily protein that links melatonin to direct regulation of the core clock gene feedback loops.

Most living organisms are able to sense the time and in particular time of day by their internal clocks. So-called clock proteins control these internal clockworks. BMAL1 and CLK are two important clock proteins, which together form a complex that serves as a transcription factor and controls the production of diurnal proteins. These diurnal proteins, in turn, inhibit the formation of clock proteins so that the concentration of the different proteins in the cell oscillates back and forth throughout the day. External factors may affect the balance of clock proteins, and one such important factor is light. Melatonin is a darkness hormone produced in the brain of most animals during the night, and here we show that melatonin controls the formation of a protein named AST2 in crayfish. AST2 belongs to a group of proteins found in many arthropods, such as spiders, scorpions, crustaceans, and some insects, whose function has been unknown until now. Now we demonstrate that AST2 is induced by melatonin at night and then functions in the internal biological clock by preventing BMAL1 and CLK to form a complex. In this way, AST2 acts as a link between melatonin and the internal biological clock.

Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation

Shift work that includes a nighttime rotation has become an unavoidable attribute of today's 24-h society. The related disruption of the human circadian time organization leads in the short-term to an array of jet-lag-like symptoms, and in the long-run it may contribute to weight gain/obesity, metabolic syndrome/type II diabetes, and cardiovascular disease. Epidemiologic studies also suggest increased cancer risk, especially for breast cancer, in night and rotating female shift workers. If confirmed in more controlled and detailed studies, the carcinogenic effect of night and shift work will constitute additional serious medical, economic, and social problems for a substantial proportion of the working population. Here, we examine the possible multiple and interconnected cancer-promoting mechanisms as a consequence of shift work, i.e., repeated disruption of the circadian system, pineal hormone melatonin suppression by exposure to light at night, sleep-deprivation-caused impairment of the immune system, plus metabolic changes favoring obesity and generation of proinflammatory reactive oxygen species.