Paradoxical sleep deprivation impairs mouse survival after infection with malaria parasites

Shifted levels of sleep and activity under darkness as mechanisms underlying ectoparasite resistance

Parasites harm host fitness and are pervasive agents of natural selection. Host defensive traits in natural populations typically show genetic variation, which may be maintained when parasite resistance imposes fitness costs on the host coupled with variability in parasite prevalence in space and/or time. Previously we demonstrated significant evolutionary responses to artificial selection for increasing behavioral immunity to Gamasodes queenslandicus mites in replicate lines of Drosophila melanogaster . Here, we report transcriptional shifts in metabolic processes between selected and control fly lines based on RNA-seq analyses. We also show decreased starvation resistance and increased use of nutrient reserves in flies from mite-resistant lines. Additionally, mite-resistant lines exhibited increased behavioral activity, reduced sleep and elevated oxygen consumption under conditions of darkness. The link between resistance and sleep was confirmed in an independent panel of D. melanogaster genetic lines exhibiting variable sleep durations, showing a positive correlation between mite resistance and reduced sleep. Experimentally restraining the activity of artificially selected mite-resistant flies during exposure to parasites under dark conditions reduced their resistance advantage relative to control flies. The results suggest that ectoparasite resistance in this system involves increased dark-condition activity and metabolic gene expression at the expense of nutrient reserves and starvation resistance.

The Effects of Acute and Chronic Sleep Deprivation on the Immune Profile in the Rat

BACKGROUND

Acute and chronic sleep deprivation present many health-related problems in modern societies, mainly concerning the immune system. Immune factors, particularly the interleukins, regulate sleep and, therefore, may be altered by sleep deprivation (SD).

OBJECTIVES

We aimed to investigate the possible effects of acute and chronic sleep deprivation on selected cytokines, including interleukins (IL-1β, IL-9, IL-17, and IL-23) and tumor necrosis factor- alpha (TNF-α).

METHODS

The animals were grouped into acute sleep-deprived (SD; for 24 hours) and chronic sleep-deprived (8 hours a day for 10, 20, and 30-days). The SD was induced using the multipleplatforms model. The serum levels of cytokines were measured using commercially available ELISA.

RESULTS

The serum levels of IL-1β were significantly reduced after acute SD, whereas they were increased after 20-days of chronic SD. The IL-9 levels were reduced after acute SD, increased after 10-days of SD, and reduced again after 30-days of SD. Conversely, the levels of IL-23 were not changed after acute SD, reduced after 10 days of SD, and increased after 30-days of SD. Levels of TNF-α were not changed after acute SD, whereas they were increased after 20 and 30- days of SD.

CONCLUSION

In conclusion, both acute and chronic SD distinctly disturb the immune profile, which might result in the emergence of various pathologies presented during sleep deprivation.

Effects of Preoperative Sleep Disorders on Anesthesia Recovery and Postoperative Pain in Patients Undergoing Laparoscopic Gynecological Surgery under General Anesthesia

Sleep disorder dramatically affects people's physical and mental health. Here, we investigated the effect of preoperative sleep disorders on anesthesia recovery and postoperative pain in patients undergoing laparoscopic gynecological surgery under general anesthesia. 120 patients who underwent elective laparoscopic gynecological surgery under general anesthesia in Taizhou Central Hospital from November 2021 to March 2022 were included. According to the score of the Pittsburgh sleep quality index (PSQI), the participating patients were divided into four groups: control group (control group), mild sleep disorder group A (group A), moderate sleep disorder group B (group B), and severe sleep disorder group C (group C), with 30 patients in each group. The changes of mean arterial pressure (MAP) and heart rate (HR) at different time points, operation time, anesthesia time, extubation time, the time when Aldrete score reached 10 points, visual analog score (VAS) serum interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) were compared among different groups. Our study demonstrated that there were no significant differences in MAP and HR among the four groups at the same time points (all P > 0.05). Significant differences in the time of extubation and Aldrete score reaching 10 points had been found among the four groups (all P < 0.001), indicating more sleep disorder induced longer extubation and recovery time. There were significant differences in VAS scores among the four groups at both different and the same time points (all P < 0.001), suggesting more sleep disorders induced more pain in the sufferers. Serum IL-6 levels were significantly higher in the three sleep disorder groups than the control group at 6 h and 24 h after the operation (all P < 0.05), while group C has the highest IL-6 levels as compared to the other group (P = 0.09 and P < 0.001, respectively). At 6 h after operation, serum levels of TNF-α in group C were significantly higher than in the control group (P = 0.044), but no significant differences were found in the other two groups (all P > 0.05). Positive correlation with preoperative PSQI score has been found with the times of extubation, the time of Aldrete score reaching 10 points, the VAS at 1 h, 6 h, and 24 h after operation, the level of serum IL-6 at 1 day before operation and 6 h and 24 h after operation, and the TNF-α at 6 h and 24 h after operation (all P < 0.001). The present study showed that the degree of preoperative sleep disorders could affect the quality of postoperative awakening and pain of patients undergoing laparoscopic gynecological surgery under general anesthesia, which might be associated with the aggravation of inflammatory reactions in the body.

Sleep disruption induces activation of inflammation and heightens risk for infectious disease: Role of impairments in thermoregulation and elevated ambient temperature

Thermoregulation and sleep are tightly coordinated, with evidence that impairments in thermoregulation as well as increases in ambient temperature increase the risk of sleep disturbance. As a period of rest and low demand for metabolic resources, sleep functions to support host responses to prior immunological challenges. In addition by priming the innate immune response, sleep prepares the body for injury or infection which might occur the following day. However when sleep is disrupted, this phasic organization between nocturnal sleep and the immune system becomes misaligned, cellular and genomic markers of inflammation are activated, and increases of proinflammatory cytokines shift from the nighttime to the day. Moreover, when sleep disturbance is perpetuated due to thermal factors such as elevated ambient temperature, the beneficial crosstalk between sleep and immune system becomes further imbalanced. Elevations in proinflammatory cytokines have reciprocal effects and induce sleep fragmentation with decreases in sleep efficiency, decreases in deep sleep, and increases in rapid eye movement sleep, further fomenting inflammation and inflammatory disease risk. Under these conditions, sleep disturbance has additional potent effects to decrease adaptive immune response, impair vaccine responses, and increase vulnerability to infectious disease. Behavioral interventions effectively treat insomnia and reverse systemic and cellular inflammation. Further, insomnia treatment redirects the misaligned inflammatory- and adaptive immune transcriptional profiles with the potential to mitigate risk of inflammation-related cardiovascular, neurodegenerative, and mental health diseases, as well as susceptibility to infectious disease.

Sleep restriction prior to antigen exposure does not alter the T cell receptor repertoire but impairs germinal center formation during a T cell-dependent B cell response in murine spleen

It is well known that sleep promotes immune functions. In line with this, a variety of studies in animal models and humans have shown that sleep restriction following an antigen challenge dampens the immune response on several levels which leads to e.g. worsening of disease outcome and reduction of vaccination efficiency, respectively. However, the inverse scenario with sleep restriction preceding an antigen challenge is only investigated in a few animal models where it has been shown to reduce antigen uptake and presentation as well as pathogen clearance and survival rates. Here, we use injection of sheep red blood cells to investigate the yet unknown effect on a T cell-dependent B cell response in a well-established mouse model. We found that 6 ​h of sleep restriction prior to the antigen challenge does not impact the T cell reaction including the T cell receptor repertoire but dampens the development of germinal centers which correlates with reduced antigen-specific antibody titer indicating an impaired B cell response. These changes concerned a functionally more relevant level than those found in the same experimental model with the inverse scenario when sleep restriction followed the antigen challenge. Taken together, our findings showed that the outcome of the T cell-dependent B cell response is indeed impacted by sleep restriction prior to the antigen challenge which highlights the clinical significance of this scenario and the need for further investigations in humans, for example concerning the effect of sleep restriction preceding a vaccination.

Preoperative REM sleep is associated with complication development after colorectal surgery

BACKGROUND

While total sleep duration and rapid eye movement (REM) sleep duration have been associated with long-term mortality in non-surgical cohorts, the impact of preoperative sleep on postoperative outcomes has not been well studied.

METHODS

In this secondary analysis of a prospective observational cohort study, patients who recorded at least 1 sleep episode using a consumer wearable device in the 7 days before elective colorectal surgery were included. 30-day postoperative outcomes among those who did and did not receive at least 6 h of total sleep, as well as those who did and did not receive at least 1 h of rapid eye movement (REM) sleep, were compared.

RESULTS

34 out of 95 (35.8%) patients averaged at least 6 h of sleep per night, while 44 out of 82 (53.7%) averaged 1 h or more of REM sleep. Patients who slept less than 6 h had similar postoperative outcomes compared to those who slept 6 h or more. Patients who averaged less than 1 h of REM sleep, compared to those who achieved 1 h or more of REM sleep, had significantly higher rates of complication development (29.0% vs. 9.1%, P = 0.02), and return to the OR (10.5% vs. 0%, P = 0.04). After adjustment for confounding factors, increased REM sleep duration remained significantly associated with decreased complication development (increase in REM sleep from 50 to 60 min: OR 0.72, P = 0.009; REM sleep ≥ 1 h: OR 0.22, P = 0.03).

CONCLUSION

In this cohort of patients undergoing elective colorectal surgery, those who developed a complication within 30 days were less likely to average at least 1 h of REM sleep in the week before surgery than those who did not develop a complication. Preoperative REM sleep duration may represent a risk factor for surgical complications; however additional research is necessary to confirm this relationship.

Genes, Environments, and Phenotypic Plasticity in Immunology

For most of its history, immunology has sought to control environmental variation to establish genetic causality. As with all biological traits though, variation among individuals arises by three broad pathways: genetic (G), environmental (E), and the interactive between the two (GxE); and immunity is no different. Here, we review the value of applying the evolutionary frameworks of phenotypic plasticity and reaction norms to immunology. Because standardized laboratory environments are vastly different from the conditions under which populations evolved, we hypothesize that immunology might presently be missing important phenotypic variation and even focusing on dysregulated molecular and cellular processes. Modest adjustments to study designs could make model organism immunology more productive, reproducible, and reflective of human physiology.

Sleep Disturbance during Infection Compromises Tfh Differentiation and Impacts Host Immunity

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

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

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RSD decreases germinal center formation and impairs specific antibody production

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Exacerbated glucocorticoid production impairs T lymphocyte differentiation

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

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.

A bidirectional relationship between sleep and oxidative stress in Drosophila

Although sleep appears to be broadly conserved in animals, the physiological functions of sleep remain unclear. In this study, we sought to identify a physiological defect common to a diverse group of short-sleeping Drosophila mutants, which might provide insight into the function and regulation of sleep. We found that these short-sleeping mutants share a common phenotype of sensitivity to acute oxidative stress, exhibiting shorter survival times than controls. We further showed that increasing sleep in wild-type flies using genetic or pharmacological approaches increases survival after oxidative challenge. Moreover, reducing oxidative stress in the neurons of wild-type flies by overexpression of antioxidant genes reduces the amount of sleep. Together, these results support the hypothesis that a key function of sleep is to defend against oxidative stress and also point to a reciprocal role for reactive oxygen species (ROS) in neurons in the regulation of sleep.

Thermoregulation as a disease tolerance defense strategy

Physiological responses that occur during infection are most often thought of in terms of effectors of microbial destruction through the execution of resistance mechanisms, due to a direct action of the microbe, or are maladaptive consequences of host-pathogen interplay. However, an examination of the cellular and organ-level consequences of one such response, thermoregulation that leads to fever or hypothermia, reveals that these actions cannot be readily explained within the traditional paradigms of microbial killing or maladaptive consequences of host-pathogen interactions. In this review, the concept of disease tolerance is applied to thermoregulation during infection, inflammation and trauma, and we discuss the physiological consequences of thermoregulation during disease including tissue susceptibility to damage, inflammation, behavior and toxin neutralization.