Cytokine-induced sickness behavior

Serum Albumin and Prealbumin in Calorically Restricted, Nondiseased Individuals: A Systematic Review

PURPOSE

Undernutrition is often suspected in patients when serum albumin or prealbumin levels are low. We asked whether these measures are indeed low in undernourished people if no inflammatory illness is present.

METHODS

We did a systematic review to identify otherwise healthy subjects who were severely nutrient-deprived due to poor access to food or unwillingness to eat. We excluded children and pregnant women. We tabulated available measures of nutrient intake, anthropometry, serum albumin and prealbumin, and, when available, changes in these measures during nutritional intervention.

RESULTS

In otherwise healthy subjects, serum albumin and prealbumin levels remained normal despite marked nutrient deprivation until the extremes of starvation, that is, body mass index <12 or more than 6 weeks of starvation.

CONCLUSIONS

In these otherwise healthy subjects, serum albumin and prealbumin levels are not "markers of nutritional status." The "markers" failed to identify subjects with severe protein-calorie malnutrition until extreme starvation. That is, they failed to identify healthy individuals who would benefit from nutrition support, becoming abnormal only when starvation was already obvious. In contrast, serum albumin and prealbumin levels are known to fall promptly with injury or illness regardless of nutrient intake. They are negative acute-phase reactants. When these measures are low in sick patients, this cannot be assumed to reflect nutritional deprivation. Decisions about nutrition support should be based on evidence of meaningful benefit from this treatment rather than on assessment of "nutritional markers."

Metabolic Risk Factors of Sporadic Alzheimer's Disease: Implications in the Pathology, Pathogenesis and Treatment

Alzheimer's disease (AD), the major cause of dementia among the elderly world-wide, manifests in familial and sporadic forms, and the latter variety accounts for the majority of the patients affected by this disease. The etiopathogenesis of sporadic AD is complex and uncertain. The autopsy studies of AD brain have provided limited understanding of the antemortem pathogenesis of the disease. Experimental AD research with transgenic animal or various cell based models has so far failed to explain the complex and varied spectrum of AD dementia. The review, therefore, emphasizes the importance of AD related risk factors, especially those with metabolic implications, identified from various epidemiological studies, in providing clues to the pathogenesis of this complex disorder. Several metabolic risk factors of AD like hypercholesterolemia, hyperhomocysteinemia and type 2 diabetes have been studied extensively both in epidemiology and experimental research, while much less is known about the role of adipokines, pro-inflammatory cytokines and vitamin D in this context. Moreover, the results from many of these studies have shown a degree of variability which has hindered our understanding of the role of AD related risk factors in the disease progression. The review also encompasses the recent recommendations regarding clinical and neuropathological diagnosis of AD and brings out the inherent uncertainty and ambiguity in this area which may have a distinct impact on the outcome of various population-based studies on AD-related risk factors.

Sick man walking: Perception of health status from body motion

An ability to detect subtle signs of sickness in others would be highly beneficial, as it would allow for behaviors that help us avoid contagious pathogens. Recent findings suggest that both animals and humans are able to detect distinctive odor signals of individuals with activated innate immune responses. This study tested whether an innate immune response affects a person's walking speed and whether other people perceive that person as less healthy. 43 subjects watched films of persons who were experiencing experimental immune activation, and rated the walking individuals in the films with respect to health, tiredness, and sadness. Furthermore, the walking speed in the films was analyzed. After LPS injections, participants walked more slowly and were perceived as less healthy and more tired as compared to when injected with placebo. There was also a trend for the subjects to look sadder after LPS injection than after placebo. Furthermore, there were strong associations between walking speed and the appearance of health, tiredness, and sadness. These findings support the notion that walking speed is affected by an activated immune response, and that humans may be able to detect very early signs of sickness in others by merely observing their gait. This ability is likely to aid both a "behavioral immune system", by providing more opportunities for adaptive behaviors such as avoidance, and the anticipatory priming of biochemical immune responses.

Histone Deacetylase Inhibitor Trichostatin A Ameliorated Endotoxin-Induced Neuroinflammation and Cognitive Dysfunction

Excessive production of cytokines by microglia may cause cognitive dysfunction and long-lasting behavioral changes. Activating the peripheral innate immune system stimulates cytokine secretion in the central nervous system, which modulates cognitive function. Histone deacetylases (HDACs) modulate cytokine synthesis and release. Trichostatin A (TSA), an HDAC inhibitor, is documented to be anti-inflammatory and neuroprotective. We investigated whether TSA reduces lipopolysaccharide- (LPS-) induced neuroinflammation and cognitive dysfunction. ICR mice were first intraperitoneally (i.p.) injected with vehicle or TSA (0.3 mg/kg). One hour later, they were injected (i.p.) with saline or Escherichia coli LPS (1 mg/kg). We analyzed the food and water intake, body weight loss, and sucrose preference of the injected mice and then determined the microglia activation and inflammatory cytokine expression in the brains of LPS-treated mice and LPS-treated BV-2 microglial cells. In the TSA-pretreated mice, microglial activation was lower, anhedonia did not occur, and LPS-induced cognitive dysfunction (anorexia, weight loss, and social withdrawal) was attenuated. Moreover, mRNA expression of HDAC2, HDAC5, indoleamine 2,3-dioxygenase (IDO), TNF-α, MCP-1, and IL-1β in the brain of LPS-challenged mice and in the LPS-treated BV-2 microglial cells was lower. TSA diminished LPS-induced inflammatory responses in the mouse brain and modulated the cytokine-associated changes in cognitive function, which might be specifically related to reducing HDAC2 and HDAC5 expression.

Investigating neural mechanisms of change of cognitive behavioural therapy for chronic fatigue syndrome: a randomized controlled trial

BACKGROUND

Chronic fatigue syndrome (CFS) is characterized by profound and disabling fatigue with no known somatic explanation. Cognitive behavioral therapy (CBT) has proven to be a successful intervention leading to a reduction in fatigue and disability. Based on previous neuroimaging findings, it has been suggested that central neural mechanisms may underlie CFS symptoms and play a role in the change brought on by CBT. In this randomized controlled trial we aim to further investigate the neural mechanisms that underlie fatigue in CFS and their change by CBT.

METHODS/DESIGN

We will conduct a randomized controlled trial in which we collect anatomical and functional magnetic resonance imaging (MRI) measures from female CFS patients before and after CBT (N = 60) or waiting list (N = 30) and compare these with measures from age and education matched healthy controls (N = 30). By including a large treatment group we will also be able to compare patients that benefit from CBT with those that do not. In addition, to further investigate the role of endocrine and immune biomarkers in CFS, we will determine cortisol and cytokine concentrations in blood, hair and/or saliva.

DISCUSSION

This project creates an unique opportunity to enhance our understanding of CFS symptoms and its change by CBT in terms of neuroanatomical, neurofunctional, endocrinological and immunological mechanisms and can help to further improve future treatments strategies.

TRIAL REGISTRATION

Dutch Trial Register #15852. Registered 9 December 2013 ( http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4311 ).

Cytotoxic chemotherapy increases sleep and sleep fragmentation in non-tumor-bearing mice

Sleep disruption ranks among the most common complaints of breast cancer patients undergoing chemotherapy. Because of the complex interactions among cancer, treatment regimens, and life-history traits, studies to establish a causal link between chemotherapy and sleep disruption are uncommon. To investigate how chemotherapy acutely influences sleep, adult female c57bl/6 mice were ovariectomized and implanted with wireless biotelemetry units. EEG/EMG biopotentials were collected over the course of 3days pre- and post-injection of 13.5mg/kg doxorubicin and 135mg/kg cyclophosphamide or the vehicle. We predicted that cyclophosphamide+doxorubicin would disrupt sleep and increase central proinflammatory cytokine expression in brain areas that govern vigilance states (i.e., hypothalamus and brainstem). The results largely support these predictions; a single chemotherapy injection increased NREM and REM sleep during subsequent active (dark) phases; this induced sleep was fragmented and of low quality. Mice displayed marked increases in low theta (5-7Hz) to high theta (7-10Hz) ratios following chemotherapy treatment, indicating elevated sleep propensity. The effect was strongest during the first dark phase following injection, but mice displayed disrupted sleep for the entire 3-day duration of post-injection sleep recording. Vigilance state timing was not influenced by treatment, suggesting that acute chemotherapy administration alters sleep homeostasis without altering sleep timing. qPCR analysis revealed that disrupted sleep was accompanied by increased IL-6 mRNA expression in the hypothalamus. Together, these data implicate neuroinflammation as a potential contributor to sleep disruption after chemotherapy.

Discovery of a novel site of opioid action at the innate immune pattern-recognition receptor TLR4 and its role in addiction

Opioids have historically, and continue to be, an integral component of pain management. However, despite pharmacokinetic and dynamic optimization over the past 100 years, opioids continue to produce many undesirable side effects such as tolerance, reward, and dependence. As such, opioids are liable for addiction. Traditionally, opioid addiction was viewed as a solely neuronal process, and while substantial headway has been made into understanding the molecular and cellular mechanisms mediating this process, research has however, been relatively ambivalent to how the rest of the central nervous system (CNS) responds to opioids. Evidence over the past 20 years has clearly demonstrated the importance of the immunocompetent cells of the CNS (glia) in many aspects of opioid pharmacology. Particular focus has been placed on microglia and astrocytes, who in response to opioids, become activated and release inflammatory mediators. Importantly, the mechanism underlying immune activation is beginning to be elucidated. Evidence suggests an innate immune pattern-recognition receptor (toll-like receptor 4) as an integral component underlying opioid-induced glial activation. The subsequent proinflammatory response may be viewed akin to neurotransmission creating a process termed central immune signaling. Translationally, we are beginning to appreciate the importance of central immune signaling as it contributes to many behavioral actions of addiction including reward, withdrawal, and craving. As such, the aim of this chapter is to review and integrate the neuronal and central immune signaling perspective of addiction.

Dysregulation of energy balance by trichothecene mycotoxins: Mechanisms and prospects

Trichothecenes are toxic metabolites produced by fungi that constitute a worldwide hazard for agricultural production and both animal and human health. More than 40 countries have introduced regulations or guidelines for food and feed contamination levels of the most prevalent trichothecene, deoxynivalenol (DON), on the basis of its ability to cause growth suppression. With the development of analytical tools, evaluation of food contamination and exposure revealed that a significant proportion of the human population is chronically exposed to DON doses exceeding the provisional maximum tolerable daily dose. Accordingly, a better understanding of trichothecene impact on health is needed. Upon exposure to low or moderate doses, DON and other trichothecenes induce anorexia, vomiting and reduced weight gain. Several recent studies have addressed the mechanisms by which trichothecenes induce these symptoms and revealed a multifaceted action targeting gut, liver and brain and causing dysregulation in neuroendocrine signaling, immune responses, growth hormone axis, and central neurocircuitries involved in energy homeostasis. Newly identified trichothecene toxicosis biomarkers are just beginning to be exploited and already open up new questions on the potential harmful effects of chronic exposure to DON at apparently asymptomatic very low levels. This review summarizes our current understanding of the effects of DON and other trichothecenes on food intake and weight growth.

A review of the neuro- and systemic inflammatory responses in post concussion symptoms: Introduction of the "post-inflammatory brain syndrome" PIBS

Post-concussion syndrome is an aggregate of symptoms that commonly present together after head injury. These symptoms, depending on definition, include headaches, dizziness, neuropsychiatric symptoms, and cognitive impairment. However, these symptoms are common, occurring frequently in non-head injured controls, leading some to question the existence of post-concussion syndrome as a unique syndrome. Therefore, some have attempted to explain post-concussion symptoms as post-traumatic stress disorder, as they share many similar symptoms and post-traumatic stress disorder does not require head injury. This explanation falls short as patients with post-concussion syndrome do not necessarily experience many key symptoms of post-traumatic stress disorder. Therefore, other explanations must be sought to explain the prevalence of post-concussion like symptoms in non-head injury patients. Many of the situations in which post-concussion syndrome like symptoms may be experienced such as infection and post-surgery are associated with systemic inflammatory responses, and even neuroinflammation. Post-concussion syndrome itself has a significant neuroinflammatory component. In this review we examine the evidence of neuroinflammation in post-concussion syndrome and the potential role systemic inflammation plays in post-concussion syndrome like symptoms. We conclude that given the overlap between these conditions and the role of inflammation in their etiologies, a new term, post-inflammatory brain syndromes (PIBS), is necessary to describe the common outcomes of many different inflammatory insults. The concept of post-concussion syndrome is in its evolution therefore, the new term post-inflammatory brain syndromes provides a better understanding of etiology of its wide-array of symptoms and the wide array of conditions they can be seen in.

Corticosterone primes the neuroinflammatory response to DFP in mice: potential animal model of Gulf War Illness

Gulf War Illness (GWI) is a multi‐symptom disorder with features characteristic of persistent sickness behavior. Among conditions encountered in the Gulf War (GW) theater were physiological stressors (e.g., heat/cold/physical activity/sleep deprivation), prophylactic treatment with the reversible AChE inhibitor, pyridostigmine bromide (PB), the insect repellent, N,N‐diethyl‐meta‐toluamide (DEET), and potentially the nerve agent, sarin. Prior exposure to the anti‐inflammatory glucocorticoid, corticosterone (CORT), at levels associated with high physiological stress, can paradoxically prime the CNS to produce a robust proinflammatory response to neurotoxicants and systemic inflammation; such neuroinflammatory effects can be associated with sickness behavior. Here, we examined whether CORT primed the CNS to mount neuroinflammatory responses to GW exposures as a potential model of GWI. Male C57BL/6 mice were treated with chronic (14 days) PB/ DEET, subchronic (7–14 days) CORT, and acute exposure (day 15) to diisopropyl fluorophosphate (DFP), a sarin surrogate and irreversible AChE inhibitor. DFP alone caused marked brain‐wide neuroinflammation assessed by qPCR of tumor necrosis factor‐α, IL6, chemokine (C‐C motif) ligand 2, IL‐1β, leukemia inhibitory factor, and oncostatin M. Pre‐treatment with high physiological levels of CORT greatly augmented (up to 300‐fold) the neuroinflammatory responses to DFP. Anti‐inflammatory pre‐treatment with minocycline suppressed many proinflammatory responses to CORT+DFP. Our findings are suggestive of a possible critical, yet unrecognized interaction between the stressor/environment of the GW theater and agent exposure(s) unique to this war. Such exposures may in fact prime the CNS to amplify future neuroinflammatory responses to pathogens, injury, or toxicity. Such occurrences could potentially result in the prolonged episodes of sickness behavior observed in GWI. Gulf War (GW) veterans were exposed to stressors, prophylactic medicines and, potentially, nerve agents in theater. Subsequent development of GW Illness, a persistent multi‐symptom disorder with features characteristic of sickness behavior, may be caused by priming of the CNS resulting in exaggerated neuroinflammatory responses to pathogens/insults. Nerve agent, diisopropyl fluorophosphate (DFP), produced a neuroinflammatory response that was exacerbated by pre‐treatment with levels of corticosterone simulating heightened stressor conditions. While prophylactic treatments reduced DFP‐induced neuroinflammation, this effect was negated when those treatments were combined with corticosterone.

Systemic lipopolysaccharide-mediated alteration of cortical neuromodulation involves increases in monoamine oxidase-A and acetylcholinesterase activity

BACKGROUND

Lipopolysaccharide (LPS)-mediated sickness behaviour is known to be a result of increased inflammatory cytokines in the brain. Inflammatory cytokines have been shown to mediate increases in brain excitation by loss of GABAA-mediated inhibition through receptor internalization or inactivation. Inflammatory pathways, reactive oxygen species and stress are also known to increase monoamine oxidase-A (MAO-A) and acetylcholinesterase (ACh-E) activity. Given that neuromodulator actions on neural circuits largely depend on inhibitory pathways and are sensitive to alteration in corresponding catalytic enzyme activities, we assessed the impact of systemic LPS on neuromodulator-mediated shaping of a simple cortical network.

METHODS

Extracellular field recordings of evoked postsynaptic potentials in adult mouse somatosensory cortical slices were used to evaluate effects of a single systemic LPS challenge on neuromodulator function 1 week later. Neuromodulators were administered transiently as a bolus (100 μl) to the bath perfusate immediately upstream of the recording site to mimic phasic release of neuromodulators and enable assessment of response temporal dynamics.

RESULTS

Systemic LPS administration resulted in loss of both spontaneous and evoked inhibition as well as alterations in the temporal dynamics of neuromodulator effects on a paired-pulse paradigm. The effects on neuromodulator temporal dynamics were sensitive to the Monoamine oxidase-A (MAO-A) antagonist clorgyline (for norepinephrine and serotonin) and the ACh-E inhibitor donepezil (for acetylcholine). This is consistent with significant increases in total MAO and ACh-E activity found in hemi-brain samples from the LPS-treated group, supporting the notion that systemic LPS administration may lead to longer-lasting changes in inhibitory network function and enzyme (MAO/ACh-E) activity responsible for reduced neuromodulator actions.

CONCLUSIONS

Given the significant role of neuromodulators in behavioural state and cognitive processes, it is possible that an inflammatory-mediated change in neuromodulator action plays a role in LPS-induced cognitive effects and could help define the link between infection and neuropsychiatric/degenerative conditions.

Preoperative and early postoperative quality of life after major surgery - a prospective observational study

BACKGROUND

Changes in health-related quality of life (HRQoL) several days after surgery have rarely been investigated. We aimed to estimate the perioperative change of HRQoL, to identify patients with clinically relevant decrease in postoperative HRQoL and to establish factors associated with this decrease in HRQoL at day 30 after major surgery.

METHODS

Patients scheduled for major surgery at a university hospital were enrolled. Based on the HRQoL SF-12 questionnaire, the preoperative physical component summary (PCS) score, preoperative mental component summary (MCS) score, and postoperative PCS and MCS scores at day 30 were recorded. Minimal clinically important difference (MCID) was defined as those with a decrease of at least one half of the standard deviation (SD) of preoperative PCS or MCS scores. Differences between the groups with or without decreased HRQoL were investigated using univariate comparisons. A multiple logistic regression model was performed to evaluate the predictive value of potential perioperative variables.

RESULTS

The mean ± SD preoperative PCS score was 38.5 ± 10.6, postoperative score was 35.1 ± 7.8 (p = .004) in 85 patients. Thirty-five patients (41.2%) had a clinically relevant decrease of the postoperative PCS score. A normal to high preoperative exercise metabolic capacity measured with metabolic equivalent of task (MET) (p = .01) was a predictor of the decrease in postoperative PCS. The mean preoperative MCS scores (p = .395) were 42.2 (SD 12.8) preoperative, and 43.45 (SD 12.4) postoperative, respectively.

CONCLUSIONS

Major surgery decreases postoperative PCS scores of HRQoL at 30 days. A normal to high exercise capacity was a predictor of a clinically relevant decrease of postoperative PCS scores.

TRIAL REGISTRATION

07-107 (Ethical Committee NAC of Geneva University Hospitals).

Early postnatal respiratory viral infection alters hippocampal neurogenesis, cell fate, and neuron morphology in the neonatal piglet

Respiratory viral infections are common during the neonatal period in humans, but little is known about how early-life infection impacts brain development. The current study used a neonatal piglet model as piglets have a gyrencephalic brain with growth and development similar to human infants. Piglets were inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) to evaluate how chronic neuroinflammation affects hippocampal neurogenesis and neuron morphology. Piglets in the neurogenesis study received one bromodeoxyuridine injection on postnatal day (PD) 7 and then were inoculated with PRRSV. Piglets were sacrificed at PD 28 and the number of BrdU+ cells and cell fate were quantified in the dentate gyrus. PRRSV piglets showed a 24% reduction in the number of newly divided cells forming neurons. Approximately 15% of newly divided cells formed microglia, but this was not affected by sex or PRRSV. Additionally, there was a sexual dimorphism of new cell survival in the dentate gyrus where males had more cells than females, and PRRSV infection caused a decreased survival in males only. Golgi impregnation was used to characterize dentate granule cell morphology. Sholl analysis revealed that PRRSV caused a change in inner granule cell morphology where the first branch point was extended further from the cell body. Males had more complex dendritic arbors than females in the outer granule cell layer, but this was not affected by PRRSV. There were no changes to dendritic spine density or morphology distribution. These findings suggest that early-life viral infection can impact brain development.

Measuring sickness behavior in the context of pancreatic cancer

Sickness behavior has been widely recognized as a symptom cluster that is associated with pro-inflammatory cytokine activation resulting from diverse conditions. The symptoms that comprise sickness behavior overlap substantially with major depressive disorder (MDD), which raises questions about the relationship between these two constructs, both of which occur frequently in patients with cancer. The construct of sickness behavior, while well-established in animal research, has rarely been applied to studies examining cytokines and depression in humans, perhaps because no reliable or validated measure of sickness behavior has been developed. We developed a version of a sickness behavior measure (the Sickness Behavior Inventory or SBI) and conducted a preliminary examination of its scale properties. Specifically, we hypothesized that a measure of sickness behavior would be significantly associated with five biomarkers of immune functioning (serum IL-6, TNF-α, IL-1b, IL-4, IL-10) in a human sample. The sample was comprised of four groups: individuals with pancreatic cancer and MDD (n = 16), individuals with pancreatic cancer and who did not have a diagnosis of MDD (n =2 6), individuals without cancer who had MDD (n = 7), and individuals who did not have cancer or MDD (n = 25). The SBI demonstrated moderate reliability (Cronbach's alpha = .66), and total scores were significantly correlated with IL-6 (rs = .26, p = .03), but not with other markers of immune functioning. Factor analysis supported a 3-factor model of sickness behavior with different associations between the three SBI factors and cytokines. These results highlight the need to further refine symptom measurement to better understand the relationships among immune functioning, cancer, depression, and sickness behavior.

Neurobehavioral burden of multiple sclerosis with nanotheranostics

Multiple sclerosis (MS) is a chronic demyelinating neurological disorder affecting people worldwide; women are affected more than men. MS results in serious neurological deficits along with behavioral compromise, the mechanisms of which still remain unclear. Behavioral disturbances such as depression, anxiety, cognitive impairment, psychosis, euphoria, sleep disturbances, and fatigue affect the quality of life in MS patients. Among these, depression and psychosis are more common than any other neurological disorders. In addition, depression is associated with other comorbidities. Although anxiety is often misdiagnosed in MS patients, it can induce suicidal ideation if it coexists with depression. An interrelation between sleep abnormalities and fatigue is also reported among MS patients. In addition, therapeutics for MS is always a challenge because of the presence of the blood-brain barrier, adding to the lack of detailed understanding of the disease pathology. In this review, we tried to summarize various behavioral pathologies and their association with MS, followed by its conventional treatment and nanotheranostics.

Comparison of Anorectic Potencies of the Trichothecenes T-2 Toxin, HT-2 Toxin and Satratoxin G to the Ipecac Alkaloid Emetine

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Anorectic effects of natural toxins were compared in the mouse.

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Parenteral and oral T-2 and HT-2 toxin exposure caused prolonged anorexia.

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Emetine was more potent when delivered orally as compared to parenterally.

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Emetine's effects were less than T-2 and HT-2 toxin and more transient.

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Parental and intranasal delivery satratoxin G caused transient anorectic effects.

Trichothecene mycotoxins, potent translational inhibitors that are associated with human food poisonings and damp-building illnesses, are of considerable concern to animal and human health. Food refusal is a hallmark of exposure of experimental animals to deoxynivalenol (DON) and other Type B trichothecenes but less is known about the anorectic effects of foodborne Type A trichothecenes (e.g., T-2 toxin, HT-2 toxin), airborne Type D trichothecenes (e.g., satratoxin G [SG]) or functionally analogous metabolites that impair protein synthesis. Here, we utilized a well-described mouse model of food intake to compare the anorectic potencies of T-2 toxin, HT-2 toxin, and SG to that of emetine, a medicinal alkaloid derived from ipecac that inhibits translation. Intraperitoneal (IP) administration with T-2 toxin, HT-2 toxin, emetine and SG evoked anorectic responses that occurred within 0.5 h that lasted up to 96, 96, 3 and 96 h, respectively, with lowest observed adverse effect levels (LOAELs) being 0.1, 0.1, 2.5 and 0.25 mg/kg BW, respectively. When delivered via natural routes of exposure, T-2 toxin, HT-2 toxin, emetine (oral) and SG (intranasal) induced anorectic responses that lasted up to 48, 48, 3 and 6 h, respectively with LOAELs being 0.1, 0.1, 0.25, and 0.5 mg/kg BW, respectively. All four compounds were generally much more potent than DON which was previously observed to have LOAELs of 1 and 2.5 mg/kg BW after IP and oral dosing, respectively. Taken together, these anorectic potency data will be valuable in discerning the relative risks from trichothecenes and other translational inhibitors of natural origin.

Diet, behavior and immunity across the lifespan

It is increasingly appreciated that perinatal events can set an organism on a life-long trajectory for either health or disease, resilience or risk. One early life variable that has proven critical for optimal development is the nutritional environment in which the organism develops. Extensive research has documented the effects of both undernutrition and overnutrition, with strong links evident for an increased risk for obesity and metabolic disorders, as well as adverse mental health outcomes. Recent work has highlighted a critical role of the immune system, in linking diet with long term health and behavioral outcomes. The present review will summarize the recent literature regarding the interactions of diet, immunity, and behavior.

Undernutrition, the acute phase response to infection, and its effects on micronutrient status indicators

Infection and undernutrition are prevalent in developing countries and demonstrate a synergistic relation. Undernutrition increases infection-related morbidity and mortality. The acute phase response (APR) is an innate, systemic inflammatory reaction to a wide array of disruptions in a host's homeostasis, including infection. Released from immune cells in response to deleterious stimuli, proinflammatory cytokines act on distant tissues to induce behavioral (e.g., anorexia, weakness, and fatigue) and systemic effects of the APR. Cytokines act to increase energy and protein requirements to manifest fever and support hepatic acute phase protein (APP) production. Blood concentrations of glucose and lipid are augmented to provide energy to immune cells in response to cytokines. Additionally, infection decreases intestinal absorption of nutrients and can cause direct loss of micronutrients. Traditional indicators of iron, zinc, and vitamin A status are altered during the APR, leading to inaccurate estimations of deficiency in populations with a high or unknown prevalence of infection. Blood concentrations of APPs can be measured in nutrition interventions to assess the time stage and severity of infection and correct for the APR; however, standardized cutoffs for nutrition applications are needed. Protein-energy malnutrition leads to increased gut permeability to pathogens, abnormal immune cell populations, and impaired APP response. Micronutrient deficiencies cause specific immune impairments that affect both innate and adaptive responses. This review describes the antagonistic interaction between the APR and nutritional status and emphasizes the need for integrated interventions to address undernutrition and to reduce disease burden in developing countries.

Bacillus Calmette-Guérin vaccine induces a selective serotonin reuptake inhibitor (SSRI)-resistant depression like phenotype in mice

Preclinical studies have shown that administration of Bacillus Calmette-Guérin (BCG) vaccine induces depression-like behaviors in mice; however, the effect of antidepressant drug treatment has not been reported earlier. In the present study, we induced depression-like behavior by administering BCG vaccine to BALB/c mice. BCG treatment produced robust serum sickness as shown by a decrease in body weight, reduced spontaneous locomotor activity and reduced voluntary wheel running activity. BCG treatment also elevated plasma IL6 and IFNγ levels and produced a marked activation of lung IDO activity. At a time point when serum sickness-related behaviors had fully recovered (i.e., day 14) BCG-treated mice showed a significant increase in immobility in the forced swim test (FST) and tail suspension test (TST) indicative of a pro-depressant phenotype. We observed significant increase in [(3)H]PK11195 binding in cortex and hippocampus regions of BGC-treated mice in comparison to saline-treated mice indicating prominent neuroinflammation. Pharmacological evaluation of FST behavior in BCG-treated mice demonstrated selective resistance to the selective serotonin reuptake inhibitors (SSRIs) fluoxetine and escitalopram. In contrast the tricyclic antidepressant imipramine, the dual serotonin/norepinephrine reuptake inhibitor (SNRI) duloxetine, and the dual dopamine/norepinephrine reuptake inhibitor (DNRI) nomifensine retained antidepressant efficacy in these mice. The lack of efficacy with acute treatment with SSRIs could not be explained either by differences in drug exposure or serotonin transporter (SERT) occupancy. Our results demonstrate that BCG-vaccine induced depression like behavior is selectively resistant to SSRIs and could potentially be employed to evaluate novel therapeutic agents being developed to treat SSRI-resistance in humans.

Kinetic characteristics of euflammation: the induction of controlled inflammation without overt sickness behavior

We found recently that controlled progressive challenge with subthreshold levels of E. coli can confer progressively stronger resistance to future reinfection-induced sickness behavior to the host. We have termed this type of inflammation "euflammation". In this study, we further characterized the kinetic changes in the behavior, immunological, and neuroendocrine aspects of euflammation. Results show euflammatory animals only display transient and subtle sickness behaviors of anorexia, adipsia, and anhedonia upon a later infectious challenge which would have caused much more severe and longer lasting sickness behavior if given without prior euflammatory challenges. Similarly, infectious challenge-induced corticosterone secretion was greatly ameliorated in euflammatory animals. At the site of E.coli priming injections, which we termed euflammation induction locus (EIL), innate immune cells displayed a partial endotoxin tolerant phenotype with reduced expression of innate activation markers and muted inflammatory cytokine expression upon ex vivo LPS stimulation, whereas innate immune cells outside EIL displayed largely opposite characteristics. Bacterial clearance function, however, was enhanced both inside and outside EIL. Finally, sickness induction by an infectious challenge placed outside the EIL was also abrogated. These results suggest euflammation could be used as an efficient method to "train" the innate immune system to resist the consequences of future infectious/inflammatory challenges.

Selective social buffering of behavioral and endocrine responses and Fos induction in the prelimbic cortex of infants exposed to a novel environment

In mammals, the presence of the mother can reduce or "buffer" stress responses of her young in threatening conditions. We compared the effect of the mother, a familiar littermate, and an unfamiliar adult male on three classes of response shown by guinea pig pups in a novel environment: short latency active behaviors, particularly vocalizing; slower developing passive behaviors that appear mediated by inflammatory mechanisms; and hypothalamic-pituitary-adrenal activity. We also examined Fos induction in the prelimbic cortex, a region hypothesized to mediate buffering effects. Only the mother significantly suppressed all classes of behavior. The greatest selectivity was observed for passive behavioral responses. Contrary to expectations, the adult male reduced plasma cortisol levels of pups as effectively as did the mother. The presence of the male also resulted in increased Fos induction in the prelimbic cortex and high levels of social interaction. Maternal buffering was not associated with prelimbic activity. These results confirm the ability of the mother to reduce active behavioral and HPA responses and suggest a specific maternal buffering effect on the later developing passive behavioral responses. The findings also demonstrate an unexpected ability of adult males to reduce HPA responses and raise the possibility that different social partners buffer HPA activity through different underlying processes.

Sick in the Head? Pathogen Concerns Bias Implicit Perceptions of Mental Illness

Biases against the mentally ill are historically and cross-culturally pervasive, suggesting they may have an evolutionary basis. The prevailing view is that people seek to distance themselves from the mentally ill because they are perceived as dangerous, violent, and incompetent. However, because of similarities between sickness behaviors and symptoms of some mental disorders, it was hypothesized that mental illness stigma could be partially explained as a function of behavioral immune system biases designed to avoid potential sources of contagion. In two experiments, it was found that mental illness was implicitly associated more with disease than danger. In Experiment 1, this implicit association was exacerbated among people who have had their biological immune system activated by a recent illness. In Experiment 2, experimentally priming disease salience increased implicit association between mental illness and disease. Implications for the evolutionary origins of prejudice and the prevention of mental illness stigma are discussed.

Cerebrospinal fluid markers of neuroinflammation in delirium: a role for interleukin-1β in delirium after hip fracture

OBJECTIVE

Exaggerated central nervous system (CNS) inflammatory responses to peripheral stressors may be implicated in delirium. This study hypothesised that the IL-1β family is involved in delirium, predicting increased levels of interleukin-1β (IL-1β) and decreased IL-1 receptor antagonist (IL-1ra) in the cerebrospinal fluid (CSF) of elderly patients with acute hip fracture. We also hypothesised that Glial Fibrillary Acidic Protein (GFAP) and interferon-γ (IFN-γ) would be increased, and insulin-like growth factor 1 (IGF-1) would be decreased.

METHODS

Participants with acute hip fracture aged >60 (N=43) were assessed for delirium before and 3-4 days after surgery. CSF samples were taken at induction of spinal anaesthesia. Enzyme-linked immunosorbent assays (ELISA) were used for protein concentrations.

RESULTS

Prevalent delirium was diagnosed in eight patients and incident delirium in 17 patients. CSF IL-1β was higher in patients with incident delirium compared to never delirium (incident delirium 1.74 pg/ml (1.02-1.74) vs. prevalent 0.84 pg/ml (0.49-1.57) vs. never 0.66 pg/ml (0-1.02), Kruskal-Wallis p=0.03). CSF:serum IL-1β ratios were higher in delirious than non-delirious patients. CSF IL-1ra was higher in prevalent delirium compared to incident delirium (prevalent delirium 70.75 pg/ml (65.63-73.01) vs. incident 31.06 pg/ml (28.12-35.15) vs. never 33.98 pg/ml (28.71-43.28), Kruskal-Wallis p=0.04). GFAP was not increased in delirium. IFN-γ and IGF-1 were below the detection limit in CSF.

CONCLUSION

This study provides novel evidence of CNS inflammation involving the IL-1β family in delirium and suggests a rise in CSF IL-1β early in delirium pathogenesis. Future larger CSF studies should examine the role of CNS inflammation in delirium and its sequelae.

Fasting Induces IL-1 Resistance and Free-Fatty Acid-Mediated Up-Regulation of IL-1R2 and IL-1RA

OBJECTIVE

Weight-loss is a near societal obsession and many diet programs use significant calorie restriction including fasting/short term starvation to generate rapid effects. Fasting is also a well-recognized cause of immunosuppression especially within the innate immune system. In this study, we sought to determine if the IL-1 arm of the neuroimmune system was down-regulated by a 24 h fast and how fasting might generate this effect.

DESIGN

Mice were allowed ad libitum access to food or had food withheld for 24 h. Expression of the endogenous IL-1 antagonists, IL-1 receptor type 2 (IL-1R2), and IL-1 receptor antagonist (IL-1RA) was determined as were sickness behaviors before and after IL-1β administration.

RESULTS

Fasting markedly increased gene expression of IL-1R2 (83-fold in adipose tissue, 9.5-fold in liver) and IL-1RA (68-fold in liver). Fasted mice were protected from IL-1β-induced weight-loss, hypoglycemia, loss of locomotor, and social anxiety. These protections were coupled to a large positive interaction of fasting and IL-1β on IL-1R2 gene expression in adipose tissue and liver (2.6- and 1.6-fold, respectively). Fasting not only increased IL-1RA and IL-1R2 protein 2.5- and 3.2-fold, respectively, in liver but also increased IL-1R2 1.8-fold in adipose tissue. Fasting, in turn, triggered a 2.4-fold increase in plasma free-fatty acids (FFAs) and a 2.1-fold increase in plasma corticosterone. Inhibition, of glucocorticoid action with mifepristone did not impact fasting-dependent IL-1R2 or IL-1RA gene expression. Administration of the FFA, palmitate, to mice increased liver IL-1R2 and IL-1RA gene expression by 14- and 11-fold, respectively.

CONCLUSION

These findings indicate that fasting augments expression of endogenous IL-1 antagonists inducing IL-1 resistance. Fasting-induced increases in plasma FFAs appears to be a signal that drives immunosuppression during fasting/short term starvation.

Effect of acute and regular exercise on growth hormone secretagogue receptor-1a expression in human lymphocytes, T cell subpopulation and monocytes

The orexigenic peptide hormone ghrelin exerts potent inhibitory effects on pro-inflammatory cytokine release via the growth hormone secretagogue receptor-1a (GHS-R1a) on T cells and monocytes. As such, ghrelin is a promising therapeutic agent for the treatment of inflammatory conditions, but these effects depend on the availability of GHS-R1a. The aim of this study was to determine the effect of acute exercise on GHS-R1a expression on circulating CD14+ monocytes, total lymphocytes and CD3+ T cells. Nine male club-standard cyclists cycled for 1h at 75% V̇O2peak (EX) or rested (REST) in a randomised cross-over design. Compared with the equivalent times in REST, the concentration of circulating GHS-R1a+ lymphocytes and monocytes was higher in EX at immediately and 1 and 2h post-exercise (all p<.05). The concentration of CD3+GHS-R1a+ cells was higher in EX than in REST immediately post-exercise only (258 (203)cellsμl(-1) vs. 62 (42)cellsμl(-1), p<.05). Density of GHS-R1a receptor expression was unaffected by trial or time. Comparison of active participants at rest with 7 age-, sex- and BMI-matched sedentary controls revealed a higher concentration of GHS-R1a+ lymphocytes in active males (p<.05). These findings suggest a preferential recruitment of specific cell subpopulations expressing GHS-R1a into the peripheral circulation with acute and regular exercise. Given that the anti-inflammatory effects of ghrelin depend on the availability of GHS-R1a, the preferential recruitment of subpopulations with high anti-inflammatory potential found here add a novel aspect to the potential mechanisms by which exercise acts to reduce pro-inflammatory cytokine levels.

The effects of gut microbiota on CNS function in humans

The role of the gastrointestinal microbiota in human brain development and function is an area of increasing interest and research. Preclinical models suggest a role for the microbiota in broad aspects of human health, including mood, cognition, and chronic pain. Early human studies suggest that altering the microbiota with beneficial bacteria, or probiotics, can lead to changes in brain function, as well as subjective reports of mood. As the mechanisms of bidirectional communication between the brain and microbiota are better understood, it is expected that these pathways will be harnessed to provide novel methods to enhance health and treat disease.

Effects of oral exposure to naturally-occurring and synthetic deoxynivalenol congeners on proinflammatory cytokine and chemokine mRNA expression in the mouse

The foodborne mycotoxin deoxynivalenol (DON) induces a ribotoxic stress response in mononuclear phagocytes that mediate aberrant multi-organ upregulation of TNF-α, interleukins and chemokines in experimental animals. While other DON congeners also exist as food contaminants or pharmacologically-active derivatives, it is not known how these compounds affect expression of these cytokine genes in vivo. To address this gap, we compared in mice the acute effects of oral DON exposure to that of seven relevant congeners on splenic expression of representative cytokine mRNAs after 2 and 6h. Congeners included the 8-ketotrichothecenes 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), fusarenon X (FX), nivalenol (NIV), the plant metabolite DON-3-glucoside (D3G) and two synthetic DON derivatives with novel satiety-inducing properties (EN139528 and EN139544). DON markedly induced transient upregulation of TNF-α IL-1β, IL-6, CXCL-2, CCL-2 and CCL-7 mRNA expressions. The two ADONs also evoked mRNA expression of these genes but to a relatively lesser extent. FX induced more persistent responses than the other DON congeners and, compared to DON, was: 1) more potent in inducing IL-1β mRNA, 2) approximately equipotent in the induction of TNF-α and CCL-2 mRNAs, and 3) less potent at upregulating IL-6, CXCL-2, and CCL-2 mRNAs. EN139528's effects were similar to NIV, the least potent 8-ketotrichothecene, while D3G and EN139544 were largely incapable of eliciting cytokine or chemokine mRNA responses. Taken together, the results presented herein provide important new insights into the potential of naturally-occurring and synthetic DON congeners to elicit aberrant mRNA upregulation of cytokines associated with acute and chronic trichothecene toxicity.

Association between adjuvant regional radiotherapy and cognitive function in breast cancer patients treated with conservation therapy

Although protracted cognitive impairment has been reported to occur after radiotherapy even when such therapy is not directed to brain areas, the mechanism remains unclear. This study investigated whether breast cancer patients exposed to local radiotherapy showed lower cognitive function mediated by higher plasma interleukin (IL)-6 levels than those unexposed. We performed the Wechsler Memory Scale-Revised (WMS-R) and measured plasma IL-6 levels for 105 breast cancer surgical patients within 1 year after the initial therapy. The group differences in each of the indices of WMS-R were investigated between cancer patients exposed to adjuvant regional radiotherapy (n = 51) and those unexposed (n = 54) using analysis of covariance. We further investigated a mediation effect by plasma IL-6 levels on the relationship between radiotherapy and the indices of WMS-R using the bootstrapping method. The radiotherapy group showed significantly lower Immediate Verbal Memory Index and Delayed Recall Index (P = 0.001, P = 0.008, respectively). Radiotherapy exerted an indirect effect on the lower Delayed Recall Index of WMS-R through elevation of plasma IL-6 levels (bootstrap 95% confidence interval = −2.6626 to −0.0402). This study showed that breast cancer patients exposed to adjuvant regional radiotherapy in conservation therapy might have cognitive impairment even several months after their treatment. The relationship between the therapy and the cognitive impairment could be partially mediated by elevation of plasma IL-6 levels.

Ecological momentary assessment of sleep, symptoms, and mood during chemotherapy for breast cancer

OBJECTIVE

This study examined the association of sleep before and during a chemotherapy (CT) cycle for breast cancer with symptoms and mood during a CT cycle.

METHODS

Twenty women undergoing CT for breast cancer completed the Pittsburgh Sleep Quality Index (PSQI) 1 h prior to a CT infusion. For 3 weeks following infusion, participants estimated sleep efficiency, minutes to sleep (sleep latency), number of nocturnal awakenings (sleep fragmentation (SF)), and sleep quality (SQ) each morning and rated symptoms (nausea, fatigue, numbness, and difficulty thinking) and mood three times daily (morning, afternoon, and evening) via ecological momentary assessments using automated handheld computers.

RESULTS

The results showed that disturbed sleep (PSQI score > 5) prior to CT infusion was associated with greater fatigue, and more negative and anxious mood throughout the 3-week CT cycle, and good pre-CT infusion sleep (PSQI score < 5) buffered anxious mood in the first days following infusion. Time-lagged analyses controlling for mood/symptom ratings reported the previous evening revealed that longer sleep latency and greater SF were associated with greater daytime fatigue; poorer SQ and greater SF were antecedents of worse morning negative mood, and greater SF was associated with feeling more passive and drowsy. No evening symptom or mood ratings were related to subsequent SQ.

CONCLUSIONS

These findings suggest that disturbed sleep before and after a CT infusion exacerbates fatigue, and negative, anxious, and drowsy mood during a CT cycle. Reducing sleep disturbance may be an important way to improve quality of life during CT.

The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain

Low-dose naltrexone (LDN) has been demonstrated to reduce symptom severity in conditions such as fibromyalgia, Crohn's disease, multiple sclerosis, and complex regional pain syndrome. We review the evidence that LDN may operate as a novel anti-inflammatory agent in the central nervous system, via action on microglial cells. These effects may be unique to low dosages of naltrexone and appear to be entirely independent from naltrexone's better-known activity on opioid receptors. As a daily oral therapy, LDN is inexpensive and well-tolerated. Despite initial promise of efficacy, the use of LDN for chronic disorders is still highly experimental. Published trials have low sample sizes, and few replications have been performed. We cover the typical usage of LDN in clinical trials, caveats to using the medication, and recommendations for future research and clinical work. LDN may represent one of the first glial cell modulators to be used for the management of chronic pain disorders.

Alpha/beta interferon receptor signaling amplifies early proinflammatory cytokine production in the lung during respiratory syncytial virus infection

Type I interferons (IFNs) are produced early upon virus infection and signal through the alpha/beta interferon (IFN-α/β) receptor (IFNAR) to induce genes that encode proteins important for limiting viral replication and directing immune responses. To investigate the extent to which type I IFNs play a role in the local regulation of inflammation in the airways, we examined their importance in early lung responses to infection with respiratory syncytial virus (RSV). IFNAR1-deficient (IFNAR1^−/−) mice displayed increased lung viral load and weight loss during RSV infection. As expected, expression of IFN-inducible genes was markedly reduced in the lungs of IFNAR1^−/− mice. Surprisingly, we found that the levels of proinflammatory cytokines and chemokines in the lungs of RSV-infected mice were also greatly reduced in the absence of IFNAR signaling. Furthermore, low levels of proinflammatory cytokines were also detected in the lungs of IFNAR1^−/− mice challenged with noninfectious innate immune stimuli such as selected Toll-like receptor (TLR) agonists. Finally, recombinant IFN-α was sufficient to potentiate the production of inflammatory mediators in the lungs of wild-type mice challenged with innate immune stimuli. Thus, in addition to its well-known role in antiviral resistance, type I IFN receptor signaling acts as a central driver of early proinflammatory responses in the lung. Inhibiting the effects of type I IFNs may therefore be useful in dampening inflammation in lung diseases characterized by enhanced inflammatory cytokine production.

IMPORTANCE The initial response to viral infection is characterized by the production of interferons (IFNs). One group of IFNs, the type I IFNs, are produced early upon virus infection and signal through the IFN-α/β receptor (IFNAR) to induce proteins important for limiting viral replication and directing immune responses. Here we examined the importance of type I IFNs in early responses to respiratory syncytial virus (RSV). Our data suggest that type I IFN production and IFNAR receptor signaling not only induce an antiviral state but also serve to amplify proinflammatory responses in the respiratory tract. We also confirm this conclusion in another model of acute inflammation induced by noninfectious stimuli. Our findings are of relevance to human disease, as RSV is a major cause of infant bronchiolitis and polymorphisms in the IFN system are known to impact disease severity.

Sociality and sickness: have cytokines evolved to serve social functions beyond times of pathogen exposure?

During pathogen exposure or some forms of stress, proinflammatory processes induce an array of motivated and behavioral adjustments termed "sickness behaviors". Although withdrawal from social interactions is a commonly observed sickness behavior, the relation between social behavior and sickness is much more complex. Sickness can suppress or stimulate social behavior. Sickness can serve as a social cue. Stressors that are social in nature can induce sickness behaviors, and sickness behavior can be readily suppressed by meaningful social stimuli. The nature, context, and timing of these effects together suggest that cytokine-induced behavior may play a role in mediating social interactions in various non-pathological conditions.

Dental caries and growth in school-age children

BACKGROUND AND OBJECTIVE

Dental caries in young children is commonly untreated and represents a public health problem. Dental caries in children is reported to affect their anthropometric outcomes, but the evidence is conflicting. Some studies found no association, whereas others found that caries was associated with underweight or overweight. The objective was to assess the relationship between dental caries status and height and weight in 6- to 8-year-old Saudi children with high caries prevalence.

METHODS

This study was a cross-sectional survey in schoolchildren aged 6 to 8 years attending military primary schools in Jeddah, Saudi Arabia. Caries status was assessed by using the dmft (decayed, missing, filled, teeth [primary teeth]) index. Height and weight were assessed by using z scores of height-for-age (HAZ), weight-for-age (WAZ), and BMI-for-age (BAZ) calculated by World Health Organization standardized procedures. Relationships between caries and HAZ, WAZ, and BAZ were assessed by using regression models.

RESULTS

A total of 417 of the 436 eligible schoolchildren with complete data were included, with a response rate of 95.6%. Their mean dmft index was 5.7 ± 4.2. There was an inverse linear relationship between caries status and children's HAZ, WAZ, and BAZ and significantly lower anthropometric outcomes for children at each consecutive group with higher levels of caries. The associations remained significant after adjusting for dental, social, and demographic variables.

CONCLUSIONS

The inverse linear association between dental caries and all anthropometric outcomes suggests that higher levels of untreated caries are associated with poorer growth in Saudi schoolchildren.

A role for orexin in cytotoxic chemotherapy-induced fatigue

Fatigue is the most common symptom related to cytotoxic chemotherapeutic treatment of cancer. Peripheral inflammation associated with cytotoxic chemotherapy is likely a causal factor of fatigue. The neural mechanisms by which cytotoxic chemotherapy associated inflammation induces fatigue behavior are not known. This lack of knowledge hinders development of interventions to reduce or prevent this disabling symptom. Infection induced fatigue/lethargy in rodents is mediated by suppression of hypothalamic orexin activity. Orexin is critical for maintaining wakefulness and motivated behavior. Though there are differences between infection and cytotoxic chemotherapy in some symptoms, both induce peripheral inflammation and fatigue. Based on these similarities we hypothesized that cytotoxic chemotherapy induces fatigue by disrupting orexin neuron activity. We found that a single dose of a cytotoxic chemotherapy cocktail (cyclophosphamide, adriamycin, 5-fluorouracil - CAF) induced fatigue/lethargy in mice and rats as evidenced by a significant decline in voluntary locomotor activity measured by telemetry. CAF induced inflammatory gene expression - IL-1R1 (p<0.001), IL-6 (p<0.01), TNFα (p<0.01), and MCP-1 (p<0.05) - in the rodent hypothalamus 6-24h after treatment during maximum fatigue/lethargy. CAF decreased orexin neuron activity as reflected by decreased nuclear cFos localization in orexin neurons 24h after treatment (p<0.05) and by decreased orexin-A in cerebrospinal fluid 16 h after treatment (p<0.001). Most importantly, we found that central administration of 1 μg orexin-A restored activity in CAF-treated rats (p<0.05). These results demonstrate that cytotoxic chemotherapy induces hypothalamic inflammation and that suppression of hypothalamic orexin neuron activity has a causal role in cytotoxic chemotherapy-induced fatigue in rodents.

Comparison of tissue damages caused by endoscopic lumbar discectomy and traditional lumbar discectomy: a randomised controlled trial

OBJECTIVES

This study aimed to compare the clinical efficacies of percutaneous endoscopic lumbar discectomy (PELD) and traditional open lumbar discectomy (OD).

METHODS

The pre-operative and post-operative blood loss, hospital stays and wound sizes of the patients in the two groups were recorded. Enzyme-Linked immunosorbent assay was used to measure the changes of interleukin-6 (IL-6), C-reactive protein (CRP) and creatine phosphokinase (CPK) pre-operation and 1 h, 6 h, 12 h, 24 h and 48 h after corresponding surgery. Visual Analog Scale and Modified MacNab Criteria were used to assess post-operative results.

RESULTS

Patients in the PELD group had less blood loss (p < 0.01), shorter hospitalization hours (p < 0.01) and smaller surgical wounds (p < 0.01) than the patients underwent traditional OD surgery. MacNab evaluated that the levels of satisfaction were above 90% in both groups post-operative six months. There was no significant difference in pain index between the two groups (p > 0.05). Furthermore, the levels of CRP, CPK and IL-6 in the PELD group were all lower than those in the OD group with a significant difference (p < 0.01).

CONCLUSION

The PELD had less damage to human tissues than the traditional OD. PELD has a clear promotional value in clinical.

Getting nervous about immunity

Twenty-five years ago, immunologists and neuroscientists had little science of mutual interest. This is no longer the case. Neuroscientists now know that the first formally defined cytokine, IL-1, activates a discrete population of hypothalamic neurons. This interaction leads to the release of glucocorticoids from the adrenal gland, a hormone that has a long history in immunoregulation. Immunologists have been surprised to learn that lymphoid cells synthesize acetylcholine, the first formally recognized neurotransmitter. This neurotransmitter suppresses the synthesis of TNF. These discoveries blur the distinction of neuroscience and immunology as distinct disciplines. There are now 37 formally recognized cytokines and their receptors, and at least 60 classical neurotransmitters plus over 50 neuroactive peptides. These findings explain why both immunologists and neuroscientists are getting nervous about immunity and highlight a real need to apply integrative physiological approaches in biomedical research.

Sickness behaviour after lipopolysaccharide treatment in ghrelin deficient mice

Ghrelin is an orexigenic hormone produced mainly by the gastrointestinal system and the brain. Much evidence also indicates a role for ghrelin in sleep and thermoregulation. Further, ghrelin was recently implicated in immune system modulation. Administration of bacterial lipopolysaccharide (LPS) induces fever, anorexia, and increased non-rapid-eye movement sleep (NREMS) and these actions are mediated primarily by proinflammatory cytokines. Ghrelin reduces LPS-induced fever, suppresses circulating levels of proinflammatory cytokines and reduces the severity and mortality of various models of experimental endotoxemia. In the present study, we determined the role of intact ghrelin signaling in LPS-induced sleep, feeding, and thermoregulatory responses in mice. Sleep-wake activity was determined after intraperitoneal, dark onset administration of 0.4, 2 and 10 μg LPS in preproghrelin knockout (KO) and wild-type (WT) mice. In addition, body temperature, motor activity and changes in 24-h food intake and body weight were measured. LPS induced dose-dependent increases in NREMS, and suppressed rapid-eye movement sleep, electroencephalographic slow-wave activity, motor activity, food intake and body weight in both Ppg KO and WT mice. Body temperature changes showed a biphasic pattern with a decrease during the dark period followed by an increase in the light phase. The effects of the low and middle doses of LPS were indistinguishable between the two genotypes. Administration of 10 μg LPS, however, induced significantly larger changes in NREMS and wakefulness amounts, body temperature, food intake and body weight in the Ppg KO mice. These findings support a role for ghrelin as an endogenous modulator of inflammatory responses and a central component of arousal and feeding circuits.

Diet-induced weight gain produces a graded increase in behavioral responses to an acute immune challenge

Sickness behaviors and fever during infection constitute an adaptive and tightly regulated mechanism designed to efficiently clear the invading pathogen from the body. Recent literature has demonstrated that changes in energy status can profoundly affect the fever response to an acute immune challenge. The purpose of the present study was to investigate whether the exacerbating effect of diet induced obesity (DIO) on the LPS-induced fever response demonstrated previously would generalize to other sickness behaviors and, further, whether incremental changes in body weight would influence these responses. Results showed that DIO male Wistar rats exhibited a higher number of sickness symptoms for a longer period after lipopolysaccharide (LPS) injection (100μg/kg) than lean rats. Similarly, they showed a more prolonged fever and a delayed recovery from LPS-induced suppression of social interaction. No difference in locomotor activity was observed between obese and lean groups. Comparisons among groups that varied in body weight showed that an 11% increase in body weight was sufficient to increase the number and duration of sickness symptoms displayed after an LPS-injection and that the severity of sickness symptoms increased with increasing body weight. Together these data suggest that DIO can have profound effects on multiple behavioral responses to an acute immune challenge placing obese organisms at higher risk of the consequences of prolonged inflammation.

Pain and cognition in multiple sclerosis

There is a high prevalence of pain, depression, and cognitive dysfunction in patients with Multiple Sclerosis (MS). These symptoms affect daily tasks resulting in a significant reduction in quality of life. Pain and cognitive changes have been studied across various animal models of MS. In these models the onset of pain and cognitive dysfunction occur early, and do not coincide with the pattern of motor deficits. This is likely underpinned by a number of different mechanisms including changes in glutamate transmission, glial cell activation, and increased levels of pro-inflammatory cytokines. Changes in pain and cognition have been described as belonging to a cluster of symptoms and have been linked through centrally driven processes. In particular, the overactive immune response can induce a state of "sickness-like behaviours" that can influence both pain and cognition. Investigating the mechanism of inflammatory sickness behaviors in MS could lead to a better understanding of the links between pain and cognition. There are currently few effective treatments for pain and cognition dysfunction in MS. Studying the relationship between these symptoms will allow better management of both symptoms.

C-reactive protein predicts fatigue independently of depression in breast cancer patients prior to chemotherapy

Heightened inflammatory activity has been proposed as a mechanism for the development of cancer-related fatigue (CRF), a common and distressing condition that can negatively affect quality of life. Inflammation is also implicated in the pathogenesis of depression, and depression is a strong predictor of CRF. Thus, the role of the pro-inflammatory cytokine network in CRF may be mediated by depression or both conditions may share similar underlying physiological processes. The current study investigated associations between fatigue, depression and inflammatory cytokine (IFN-γ, IL-6, TNF-α) and CRP concentrations, as well as kynurenine pathway (KP) activation, in 61 breast cancer patients prior to chemotherapy. Changes in inflammatory markers and KP activation over time were also explored, and associations with changes in fatigue and depression were examined. Higher levels of CRP were significantly correlated with fatigue and depression before chemotherapy; nevertheless, CRP predicted fatigue independently of depression. Although greater kynurenine concentrations were associated with increased immune activation, there was no evidence that the KP played a role in fatigue or depression. Furthermore, no relationships emerged between either fatigue or depression and IFN-γ, IL-6, or TNF-α before chemotherapy. Nevertheless, kynurenine levels pre- and post-treatment significantly predicted changes in depression, suggesting that heightened KP activation may contribute to depressive symptoms in patients treated for cancer. In addition, IL-6 significantly covaried with fatigue. These preliminary findings provide some support for the idea that low-grade inflammation contributes to the development of CRF, independently of depression; however, there was no evidence that this is mediated by KP activity.

Antisomnogenic cytokines, quality of life, and chronic rhinosinusitis: a pilot study

OBJECTIVES/HYPOTHESIS

Sleep disturbance, reduced quality of life (QOL), and other components of "sickness behavior" in patients with chronic rhinosinusitis (CRS) are poorly understood. These complex changes in central behavior are due to the effects of immune mediators acting in the brain. We hypothesized that immune mediators that have been associated with CRS are also associated with sickness behavior, somnifacient complaints, and CRS disease-specific QOL.

STUDY DESIGN

Pilot study.

METHODS

Twenty patients with CRS were prospectively enrolled and completed the Pittsburgh Sleep Quality Index (PSQI), disease-specific QOL, and olfactory instruments. Ethmoid mucosa was obtained and reverse transcription-polymerase chain reaction was performed for the cytokines interleukin (IL)-4, -13, and transforming growth factor-β (TGF-β). Average change in crossover threshold was calculated, and differences in gene expression were correlated with sleep quality, CRS-specific QOL, and disease severity.

RESULTS

Patients with CRS reported overall poor sleep quality and poor CRS-specific QOL with significant correlations between them. Increased expression of TGF-β (r = -0.443; P = .050) and IL-4 (r = -0.548; P = .012) correlated with sleep dysfunction, whereas IL-13 expression was linearly associated with worse sleep quality (PSQI scores r = -0.417; P = .075). IL-4 and TGF-β expression was not associated with CRS disease severity or QOL, whereas significantly higher levels of IL-13 expression correlated with worse CRS disease severity and QOL.

CONCLUSIONS

Patients with CRS exhibited behavioral changes commonly referred to as sickness behavior, which include poor sleep quality and reduced QOL. The upregulation of IL-4 and TGF-β may contribute to inflammatory brain-mediated effects on sleep quality, whereas IL-13 may be a pleiotropic signaling molecule influencing sleep, QOL, and CRS disease severity.

LEVEL OF EVIDENCE

2b.