Cortisol and immunity

A systematic review and meta-analysis of cortisol levels in Plasmodium infections

Malaria has complex interactions with host physiology, including alterations in cortisol levels. Cortisol, a key hormone in the stress response, is known to be dysregulated in various infectious diseases. This systematic review and meta-analysis aimed to elucidate the relationship between Plasmodium infection and cortisol levels, shedding light on the intricate interplay between the parasite and the host's endocrine system. The methodological protocol for assessing cortisol levels in malaria patients was registered in PROSPERO (CRD42024496578), a widely recognized international prospective register of systematic reviews. This registration ensures transparency and minimizes the risk of bias in our research. A comprehensive search strategy was employed across major databases, including Embase, PubMed, Scopus, and Medline, to include studies that reported cortisol levels in infected patients. The qualitative synthesis was undertaken to synthesize the difference in cortisol levels between malaria-infected and uninfected individuals. The meta-analysis employed the random effects model in the quantitative synthesis to calculate the effect estimate. The review included a total of 20 studies, with a substantial number conducted in Africa, followed by Asia and South America. Most included studies (13/20, 65%) reported higher cortisol levels in infected patients than in uninfected patients. The meta-analysis confirmed significantly higher cortisol levels in infected patients compared to uninfected individuals (P < 0.0001, standardized mean difference (SMD): 1.354, 95% confidence interval: 0.913 to 1.795, I2: 88.3%, across 15 studies). Notably, the method for cortisol measurement and the type of blood sample used (serum or plasma) were significant moderators in the analysis, indicating that these factors may influence the observed relationship between Plasmodium infection and cortisol levels. The systematic review and meta-analysis confirmed that Plasmodium infection is associated with increased cortisol levels, highlighting the intricate relationship between the disease and the host stress response. These findings underscore the potential of cortisol as a supplementary biomarker for understanding the pathophysiological impact of malaria. By providing insights into the stress-related mechanisms of malaria, this comprehensive understanding can inform future research and potentially enhance disease management and treatment strategies, particularly in regions heavily burdened by malaria.

Iron/iron oxide-based magneto-electrochemical sensors/biosensors for ensuring food safety: recent progress and challenges in environmental protection

Foodborne diseases have arisen due to the globalization of industry and the increase in urban population, which has led to increased demand for food and has ultimately endangered the quality of food. Foodborne diseases have caused some of the most common public health problems and led to significant social and economic issues worldwide. Food quality and safety are affected by microbial contaminants, growth-promoting feed additives (β-agonists and antibiotics), food allergens, and toxins in different stages from harvesting to storage and marketing of products. Electrochemical biosensors, due to their reduced size and portability, low cost, and low consumption of reagents and samples, can quickly provide valuable quantitative and qualitative information about food contamination. In this regard, using nanomaterials can increase the sensitivity of the assessment. Magnetic nanoparticle (MNP)-based biosensors, especially, are receiving significant attention due to their low-cost production, physicochemical stability, biocompatibility, and eco-friendly catalytic characteristics, along with magnetic, biological, chemical and electronic sensing features. Here, we provide a review on the application of iron-based magnetic nanoparticles in the electrochemical sensing of food contamination. The types of nanomaterials used in order to improve the methods and increase the sensitivity of the methods have been discussed. Then, we stated the advantages and limitations of each method and tried to state the research gaps for each platform/method. Finally, the role of microfluidic and smartphone-based methods in the rapid detection of food contamination is stated. Then, various techniques like label-free and labelled regimes for the sensitive monitoring of food contamination were surveyed. Next, the critical role of antibody, aptamer, peptide, enzyme, DNA, cells and so on for the construction of specific bioreceptors for individual and simultaneous recognition by electrochemical methods for food contamination were discussed. Finally, integration of novel technologies such as microfluidic and smartphones for the identification of food contaminations were investigated. It is important to point out that, in the last part of each sub-section, attained results of different reports for each strategy were compared and advantages/limitations were mentioned.

Cananga odorata Aromatherapy Reduces Anxiety in Unexperienced Patients Hospitalized for Interventional Neuroradiology Procedures: A Randomized Control Trial

The hospitalization and the unfamiliar experiences of patients in interventional radiology procedures cause a moderate to high levels of anxiety. This study was aimed to evaluate the anxiolytic effect of Cananga odorata essential oil (COE) aromatherapy in unexperienced patients hospitalized for interventional neuroradiology (INR) procedures. Forty-four patients admitted for their first INR procedure were randomly divided into COE and placebo control groups. COE or distilled water was dropped onto 2 pieces of mulberry paper and attached to the participant's gown at the shoulder level overnight. The main outcomes were observed from the morning salivary cortisol levels and salivary alpha-amylase activity after intervention. The Thai version of Spielberger State-Trait Anxiety Inventory (STAI) and the vital signs (blood pressure and heart rate) were also assessed before and after COE intervention as the secondary outcome. The demographic and baseline data of both groups did not show any significant difference. After intervention, COE group had a significantly lower salivary alpha-amylase activity than placebo control group. The post-intervention scores of Trait (STAI-T) and State (STAI-S) anxiety were significantly less than those of baseline in both groups. Interestingly, the COE group had a greater percentage reduction on STAI-T after intervention than placebo control group. No significant difference was observed in other outcomes. In addition, the salivary alpha-amylase activity was weak but showed significant correlation with STAI anxiety scores. This study indicates that COE aromatherapy reduces the saliva alpha amylase activity and STAI-T anxiety in unexperienced patients hospitalized for INR procedures.

Measuring stress: a review of the current cortisol and dehydroepiandrosterone (DHEA) measurement techniques and considerations for the future of mental health monitoring

Psychological stress and its inevitable trajectory toward mental health deteriorations such as clinical and major depression has become an unprecedented global burden. The diagnostic procedures involved in the characterization of mental illnesses commonly follow qualitative and subjective measures of stress, often leading to greater socioeconomic burdens due to misdiagnosis and poor understanding of the severity of such illnesses, further fueled by the stigmatization surrounding mental health. In recent years, the application of cortisol and stress hormone measurements has given rise to an alternative, quantifiable approach for the psychological evaluation of stress and depression. This review comprehensively evaluates the current state-of-the-art technology for measuring cortisol and dehydroepiandrosterone (DHEA) and their applications within stress monitoring in humans. Recent advancements in these fields have shown the importance of measuring stress hormones for the characterization of stress manifestation within the human body, and its relevance in mental health decline. Preliminary results from studies considering multimodal approaches toward stress monitoring have showcased promising developments, emphasizing the need for further technological advancement in this field, which consider both neurochemical and physiological biomarkers of stress, for global benefit.

The early function of cortisol in liver during Aeromonas hydrophila infection: Dynamics of the transcriptome and accessible chromatin landscapes

In China, channel catfish (Ictalurus punctatus) is an important aquaculture species; however, haemorrhagic disease (Aeromonas hydrophila induced disease) in these fish has caused tremendous economic loss due to high morbidity and mass mortality in the breeding industry. The role of cortisol in bacterial diseases, particularly in the acute phase, remains unclear. In this study, liver transcriptome (RNA-seq) and chromatin accessibility (ATAC-seq) analyses were employed to investigate the early functional role of cortisol in Aeromonas hydrophila-stimulated responses. Our experiments confirmed that A. hydrophila infection can initially significantly increase serum cortisol levels at 1 h after infection. At this time point, the increased serum cortisol levels can significantly regulate A. hydrophila-regulated genes by affecting both transcriptome and chromatin accessibility. Cross-analysis of RNA-seq and ATAC-seq revealed that a certain gene group (92 target_DEGs) was regulated at an early time point by cortisol. KEGG enrichment analysis revealed that the top three pathways according to target_DEGs were cancer, glutathione metabolism, and the Notch signalling pathway. The protein-protein interaction analysis of target_DEGs revealed that they may be primarily involved in cell proliferation, CD8⁺ T cell function, glutathione synthesis, and activation of the NF-κB signalling pathway. This suggests that after the emergence of immune stress, the early regulation of cortisol is positive against the immune response. It is possible that in this situation, the animal is attempting to avoid dangerous situations and risks and then cope with the imbalance produced by the stressor to ultimately restore homeostasis. Our results will contribute to future research on fish and provide valuable insight regarding the mechanism of immune regulation by cortisol and the study of bacterial haemorrhagic disease in channel catfish.

Determination of salivary cortisol and salivary pH level in gaming teenagers - A cross-sectional study

Introduction

Internet gaming disorder and cybervictimization has a disproportionate increase during the COVID 19 pandemic. Teenagers and adolescents have high risk for addiction to online gaming. Online gaming increases the stress level of the users affecting the general and the oral health. The study aims to determine the salivary cortisol and salivary pH among the gaming teenagers.

Materials and methods

The cross-sectional study recruited 45 gaming teenagers with the mean age of 15.5 years. The participants were stratified according to the type of online gaming played as mind, aggressive and betting gaming. Their salivary pH and salivary cortisol were assessed. The collected data was analyzed using SPSS version 23.

Results

The mean salivary pH was found to be less among females playing aggressive games (7.11 ± 0.30) and males playing mind games (7.24 ± 0.16). Salivary cortisol level was found to be statistically high in males (6.66 ± 1.33) and females (7.82 ± 0.66) playing aggressive games. The sub-group analysis of salivary pH and cortisol for gender showed a significant difference in the mean salivary cortisol level (p < 0.05) with no difference in the salivary pH (p > 0.05). Based on the number of hours spent in online gaming, there was a significant increase in the mean salivary cortisol level among the participants playing >3 h (p < 0.05).

Conclusion

Salivary cortisol is high among individuals playing aggressive games compared to mind and betting games. Also, salivary cortisol is high in females compared to males with no change in salivary pH.

Comprehensive Characterization of the Regulatory Landscape of Adrenocortical Carcinoma: Novel Transcription Factors and Targets Associated with Prognosis

We reconstructed a transcriptional regulatory network for adrenocortical carcinoma (ACC) using transcriptomic and clinical data from The Cancer Genome Atlas (TCGA)-ACC cohort. We investigated the association of transcriptional regulatory units (regulons) with overall survival, molecular phenotypes, and immune signatures. We annotated the ACC regulons with cancer hallmarks and assessed single sample regulon activities in the European Network for the Study of Adrenal Tumors (ENSAT) cohort. We found 369 regulons associated with overall survival and subdivided them into four clusters: RC1 and RC2, associated with good prognosis, and RC3 and RC4, associated with worse outcomes. The RC1 and RC3 regulons were highly correlated with the 'Steroid Phenotype,' while the RC2 and RC4 regulons were highly correlated with a molecular proliferation signature. We selected two regulons, NR5A1 (steroidogenic factor 1, SF-1) and CENPA (Centromeric Protein A), that were consistently associated with overall survival for further downstream analyses. The CENPA regulon was the primary regulator of MKI-67 (a marker of proliferation KI-67), while the NR5A1 regulon is a well-described transcription factor (TF) in ACC tumorigenesis. We also found that the ZBTB4 (Zinc finger and BTB domain-containing protein 4) regulon, which is negatively associated with CENPA in our transcriptional regulatory network, is also a druggable anti-tumorigenic TF. We anticipate that the ACC regulons may be used as a reference for further investigations concerning the complex molecular interactions in ACC tumors.

Polymorphonuclear leucocyte phagocytic function, γδ T-lymphocytes and testosterone as separate stress-responsive markers of prolonged, high-intensity training programs

Excessive exercise with limited recovery may lead to detrimental states of overreaching or the overtraining syndrome. Chronic maladaptation in endocrine and immune mechanisms occur with the incidence of these states. Exercise-induced cortisol and testosterone responses have been proposed as biomarkers of overreaching, with blunted responses following intensified-training periods. Yet, limited information on the effects of overreaching in immunity is available. Healthy individuals completed a 30-min running protocol (the RPE_TP) before and after a 12-day intensified-training period. Blood and saliva were collected before, after and 30min after RPE_TP at pre-training and post-training. Plasma and salivary cortisol and testosterone, leucocyte proliferation and polymorphonuclear leucocyte phagocytic activity were examined. Plasma and salivary cortisol were acutely unaffected pre-training (-14% and 0%, p ​> ​0.05) and post-training (-14% and +46%, p ​> ​0.05). Comparing pre-training with post-training, blunted responses were observed in plasma testosterone (43%-19%, p ​< ​0.05) and salivary testosterone (55%-24%, p ​> ​0.05). No acute or resting changes in total leucocyte counts or most leucocyte subsets occurred pre-training or post-training. Yet, a 194% acute elevation in γδ T-lymphocyte number occurred pre-training (p ​< ​0.05), and average resting concentrations were 174% higher post-training. Baseline phagocytic activity was 47% lower post-training (p ​< ​0.05). Intensified training was detrimental, significantly reducing phagocytic activity. Testosterone blunted post-training, indicating an excessive training-related hypothalamic-pituitary gonadal dysfunction. The γδ T-lymphocytes sensitivity to exercise was noted, rendering it as a potential stress-responsive cellular marker. The usefulness of the RPE_TP to track the onset of overreaching is proposed.

Waistline to the gumline: Relationship between obesity and periodontal disease-biological and management considerations

Obesity is a pandemic and periodontitis is the sixth most prevalent disease in the world. These two noncommunicable diseases share several risk determinants. Epidemiologic evidence from the last 2 decades has established an increase in periodontitis prevalence in obese and overweight individuals. Biologic mechanisms potentially linking obesity and periodontal disease are adiposity-associated hyperinflammation, microbial dysbiosis, altered immune response, specific genetic polymorphisms, and increased stress. However, because of the lack of longitudinal interventional studies and randomized clinical trials, there is insufficient evidence to determine the cause-effect relationship between these two diseases. Despite this, the negative impact of obesity on oral health is well established. Several logistic and physiologic complications are associated with treating obese patients in a dental setting, and it requires an interprofessional team approach. Oral health care professionals need to be aware of the specific management considerations while rendering for this cohort, including modified practice facility and equipment, tailored supportive periodontal therapy, and heightened precaution during conscious sedation and surgical procedures.

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.

Application of Salivary Biomarkers in the Diagnosis of Fibromyalgia

Fibromyalgia (FM) is a highly prevalent syndrome that impairs the quality of life of the patients; however, its diagnosis is complex and mainly centered on pain symptoms. The study of salivary biomarkers has proven highly useful for the diagnosis and prognosis of numerous diseases. The objective of this review was to gather published data on the utilization of salivary biomarkers to facilitate and complement the diagnosis of FM. Salivary biomarkers used in FM diagnosis include cortisol; calgranulin; and the enzymes α-amylase, transaldolase, and phosphoglycerate mutase. Increased serum levels of C-reactive protein, cytokines interleukin 1-β, interleukin 6, interleukin 8, interleukin 10, interleukin 17, tumor necrosis factor α, and various chemokines may serve as salivary biomarkers, given observations of their increased serum levels in patients with FM. Further research is warranted to study in depth the role and performance of biomarkers currently used in FM diagnosis/prognosis and to identify novel salivary biomarkers for this disease.

Selective detection of complex gas mixtures using point contacts: concept, method and tools

Of all modern nanosensors using the principle of measuring variations in electric conductance, point-contact sensors stand out in having a number of original sensor properties not manifested by their analogues. The nontrivial nature of point-contact sensors is based on the unique properties of Yanson point contacts used as the sensing elements. The quantum properties of Yanson point contacts enable the solution of some of the problems that could not be solved using conventional sensors measuring conductance. In the present paper, we demonstrate this by showing the potential of quantum point-contact sensors to selectively detect components of a gas mixture in real time. To demonstrate the high efficiency of the proposed approach, we analyze the human breath, which is the most complex of the currently known natural gas mixtures with extremely low concentrations of its components. Point-contact sensors allow us to obtain a spectroscopic profile of the mixture. This profile contains information about the complete set of energy interactions occurring in the point contact/breath system when the breath constituents adsorb to and desorb from the surface of the point-contact conduction channel. With this information we can unambiguously characterize the analyzed system, since knowing the energy parameters is key to successfully identifying and modeling the physicochemical properties of various quantum objects. Using the point-contact spectroscopic profile of a complex gas mixture it is possible to get a functional dependence of the concentration of particular breath components on the amplitude of the sensor output signal. To demonstrate the feasibility of the proposed approach, we analyze the point-contact profiles from the breath of several patients and compare them with the concentrations of serotonin and cortisol in the body of each patient. The obtained results demonstrate that the proposed methodology allows one to get an effective calibration function for a non-invasive analysis of the level of serotonin and cortisol in the human body using the point-contact breath test. The present study indicates some necessary prerequisites for the design of fast detection methods using differential sensor analysis in real time, which can be implemented in various areas of science and technology, among which medicine is one of the most important.

Circadian Rhythm Disruption and Sepsis in Severe Trauma Patients

BACKGROUND

Circadian rhythms are important regulators of immune functions. Admission to an intensive care unit may impact molecular clock activity and host response. Our objective was to assess and compare the immune circadian rhythms in trauma patients who develop and in those who do not develop sepsis.

METHODS

Blood samples were collected from severe trauma patients within 4 days after admission, with collections taking place every 4 h over a 24-h period. Cortisol and cytokines were measured with immunoassays. Whole-blood expression of 3 clock genes (Bmal1, Per2, and Per3) was studied by reverse transcription quantitative polymerase chain reaction. Neutrophils, monocytes, and lymphocytes were analyzed by flow cytometry. Patients with and without sepsis were compared with the cosinor mixed model to estimate mesors, amplitudes, and acrophases.

RESULTS

Thirty-eight patients were enrolled in the study, and 13 developed at least 1 septic episode. The septic patients had higher levels of cortisol than the nonseptic patients (mesor at 489 nmol/L vs. 405 nmol/L, P < 0.05) and delayed acrophases (22 h vs. 15 h, P < 0.05). They also had lower lymphocyte counts (mesor at 785 vs. 1,012 cells/μL, P < 0.05), higher neutrophil counts (mesor at 7,648 vs. 7,001 cells/μL, P < 0.05), and monocyte counts (mesor at 579 vs. 473 cells/μL, P < 0.05) than the nonseptic patients. Although no amplitude difference was identified, the acrophases were significantly different between the 2 groups for lymphocytes, interleukin 10 and tumor necrosis factor.

CONCLUSION

We demonstrated that all trauma patients had impaired circadian rhythms of cortisol, cytokines, leukocytes, and clock genes. Early circadian disruption was associated with the occurrence of sepsis and might be a marker of sepsis severity.

An Improved Label-Free Indirect Competitive SPR Immunosensor and Its Comparison with Conventional ELISA for Ractopamine Detection in Swine Urine

Ractopamine (RCT) is banned for use in animals in many countries, and it is urgent to develop efficient methods for specific and sensitive RCT detection. A label-free indirect competitive surface plasmon resonance (SPR) immunosensor was first developed with a primary antibody herein and then improved by a secondary antibody for the detection of RCT residue in swine urine. Meanwhile, a pre-incubation process of RCT and the primary antibody was performed to further improve the sensitivity. With all the key parameters optimized, the improved immunosenor can attain a linear range of 0.3-32 ng/mL and a limit of detection (LOD) of 0.09 ng/mL for RCT detection with high specificity. Furthermore, the improved label-free SPR immunosenor was compared thoroughly with a conventional enzyme-linked immunosorbent assay (ELISA). The SPR immunosensor showed advantages over the ELISA in terms of LOD, reagent consumption, analysis time, experiment automation, and so on. The SPR immunosensor can be used as potential method for real-time monitoring and screening of RCT residue in swine urine or other samples. In addition, the design using antibody pairs for biosensor development can be further referred to for other small molecule detection.

Comparison of the effects of acute exercise after overnight fasting and breakfast on energy substrate and hormone levels in obese men

[Purpose] We compared the effects of acute aerobic exercise following overnight fasting and breakfast on energy substrate and hormone levels in obese male college students. [Subjects and Methods] This crossover study recruited 10 obese male college students with a body mass index >25 kg/m² or >20% body fat. One week post-recruitment, the subjects exercised in the morning after an overnight fast. At 2 weeks, they exercised post-breakfast. Energy substrate (glucose, free fatty acid) and metabolic hormone (insulin, growth hormone, and cortisol) levels were measured immediately before and after exercise and at 60 min post-exercise. [Results] We observed interaction effects between the measurement time and exercise treatment for glucose; significant differences between measurement times and between exercise treatments for free fatty acids; interaction effects between the measurement time and exercise treatment for insulin and significant differences in the measurement time; significance differences between measurement times and between exercise treatments for growth hormone; and significant differences between measurement times and between exercise treatments for cortisol. [Conclusion] Morning exercise following an overnight fast can be more effective in reducing body fat than post-prandial exercise. However, increased cortisol levels following exercise after overnight fasting may negatively affect long-term weight loss in obese men.

Circadian characteristics of permissive and suppressive effects of cortisol and their role in homeostasis and the acute inflammatory response

In this work we explore a semi-mechanistic model that considers cortisol's permissive and suppressive effects through the regulation of cytokine receptors and cytokines respectively. Our model reveals the proactive role of cortisol during the resting period and its reactive character during the body's activity phase. Administration of an acute LPS dose during the night, when cortisol's permissive effects are higher than suppressive, leads to increased cytokine levels compared to LPS administration at morning when cortisol's suppressive effects are higher. Interestingly, our model presents a hysteretic behavior where the relative predominance of permissive or suppressive effects results not only from cortisol levels but also from the previous states of the model. Therefore, for the same cortisol levels, administration of an inflammatory stimulus at cortisol's ascending phase, that follows a time period where cytokine receptor expression is elevated ultimately sensitizing the body for the impending stimulus, leads to higher cytokine expression compared to administration of the same stimulus at cortisol's descending phase.

Pathogenesis and treatment of HIV infection: the cellular, the immune system and the neuroendocrine systems perspective

Infections with HIV represent a great challenge for the development of strategies for an effective cure. The spectrum of diseases associated with HIV ranges from opportunistic infections and cancers to systemic physiological disorders like encephalopathy and neurocognitive impairment. A major progress in controlling HIV infection has been achieved by highly active antiretroviral therapy (HAART). However, HAART does neither eliminate the virus reservoirs in form of latently infected cells nor does it completely reconstitute immune reactivity and physiological status. Furthermore, the failure of the STEP vaccine trial and the only marginal efficacies of the RV144 trial together suggest that the causal relationships between the complex sets of viral and immunological processes that contribute to protection or disease pathogenesis are still poorly understood. Here, we provide an up-to-date overview of HIV-host interactions at the cellular, the immune system and the neuroendocrine systems level. Only by integrating this multi-level knowledge one will be able to handle the systems complexity and develop new methodologies of analysis and prediction for a functional restoration of the immune system and the health of the infected host.

Stress- and aging-associated modulation of macrophage functions

Effects of environmental (cold) stress and aging on cells in monocyte/macrophage lineage were investigated. We demonstrated that immune suppressive states seen in acute cold-stressed mice (8-10 weeks of age) is attributable to FcγRII(bright) suppressor macrophages. Serum corticosterone levels were markedly increased in acute cold-stressed mice. In addition, expression of glucocorticoids (GC) receptor mRNA was observed in FcγRII(bright) cells from these mice. The increase of FcγRII(bright) cells in peritoneal exudate cells caused by acute cold stress was inhibited by adrenalectomy or administration of a saturating amount of the GC antagonist RU 38486 (mifepristone). On the contrary, administration of the GC agonist, dexamethasone, markedly increased the proportion of FcγRII(bright) cells in peritoneal exudate cells of control mice. These results suggest that the generation of FcγRII(bright) suppressor cells of monocyte/macrophage lineage by acute cold stress was mediated by action of GC through the GC receptor. We likewise found that the proportion of FcγRII(bright) suppressor macrophages is increased in aged mice (22-24 months of age). Meanwhile, activated macrophages which function as antigen presenting cells were decreased in aged rats. Both the basal corticosterone concentrations in serum and the expression of mRNA for GC receptor in peritoneal macrophages increased significantly in aged animals, suggesting that these populational and functional changes of macrophages in aged animals were mediated, in part, by the increased basal levels of GC. This is probably being responsible for immunosenescence.

Major depressive disorder, generalised anxiety disorder, and their comorbidity: associations with cortisol in the Vietnam Experience Study

OBJECTIVES

The aim of these analyses was to examine the association of cortisol, dehydroepiandrosterone sulphate (DHEAS), and the cortisol:DHEAS ratio with the diagnoses of major depressive disorder (MDD), generalised anxiety disorder (GAD), and their comorbidity.

DESIGN

This was a cross-sectional study.

METHODS

Participants were 4256 Vietnam era US army veterans. From military service files, telephone interviews, and a medical examination, occupational, socio-demographic, and health data were collected. One-year prevalence of MDD and GAD was determined through a diagnostic interview schedule based on the DSM-IV criteria. Contemporary morning fasted cortisol and DHEAS concentrations were determined. Analyses of covariance were run, first with adjustment for age and then additionally adjusting for a range of candidate confounders.

RESULTS

In fully adjusted analyses, there was evidence of lower basal cortisol levels in individuals with MDD and co-morbid MDD and GAD than those with GAD alone or no diagnosis.

CONCLUSION

This suggests that MDD and its comorbidity can also be characterised by low as well as high cortisol levels. A profitable line of future research might be to examine cortisol and DHEAS levels in more representative samples including older participants and women with and without MDD, GAD, and other psychiatric diagnoses.

Stress conditioning in mice: alterations in immunity and tumor growth

The neuroendocrine and autonomic nervous systems are known regulators of brain-immune interaction. However, the functional significance of this interaction under stress is not fully understood. We investigated the effect of a stress paradigm by applying electric foot shock followed by three reminders, on behavior, immune parameters, and lymphoma tumor growth. Male C3H mice were divided into two groups: Group 1-exposed to electric foot shock followed by three reminders, and Group 2-untreated (controls). Sets of mice underwent the elevated plus maze, staircase, and hot plate tests. After foot shock, natural killer (NK) cell activity, and lymphocyte proliferation were measured. In addition, sets of mice were either vaccinated twice with B-cell lymphoma 38C-13 immunoglobulin for determination of anti-idiotype (Id) antibodies in sera, or inoculated with tumor cells and monitored for tumor development and survival time. Mice exposed to electric foot shock followed by the three reminders had higher NK cell activity, levels of anti-Id antibodies, and a higher proliferation rate of splenocytes in response to mitogens, than the control mice. The exposed mice also showed attenuated tumor growth. Thus, the stress paradigm inhibited tumor development and lead to some immune changes that were not accompanied by behavioral changes.

Paired hormone response elements predict caveolin-1 as a glucocorticoid target gene

Glucocorticoids act in part via glucocortocoid receptor binding to hormone response elements (HREs), but their direct target genes in vivo are still largely unknown. We developed the criterion that genomic occurrence of paired HREs at an inter-HRE distance less than 200 bp predicts hormone responsiveness, based on synergy of multiple HREs, and HRE information from known target genes. This criterion predicts a substantial number of novel responsive genes, when applied to genomic regions 10 kb upstream of genes. Multiple-tissue in situ hybridization showed that mRNA expression of 6 out of 10 selected genes was induced in a tissue-specific manner in mice treated with a single dose of corticosterone, with the spleen being the most responsive organ. Caveolin-1 was strongly responsive in several organs, and the HRE pair in its upstream region showed increased occupancy by glucocorticoid receptor in response to corticosterone. Our approach allowed for discovery of novel tissue specific glucocorticoid target genes, which may exemplify responses underlying the permissive actions of glucocorticoids.

The periparturient relaxation of immunity in Merino ewes infected with Trichostrongylus colubriformis: endocrine and body compositional responses

The temporal association between the periparturient rise in worm egg count of grazing Merino ewes to infection with Trichostrongylus colubriformis and the underlying causal mechanisms was investigated in an experiment that incorporated two levels of pregnancy (pregnant or unmated), two levels of infection (infected with 6000 T. colubriformis L(3)/week or uninfected) and, following lambing, three levels of lactation (non-lactating/"dry", early-weaned 2 days after parturition, or suckled). In addition to parasitological and host immune responses reported in a previous paper (Beasley et al., 2010), a range of endocrine and body compositional changes were monitored from day -50 to day 42, relative to the midpoint of lambing (day 0). By day -19, pregnant ewes had begun to mobilise fat and eye muscle, and after 42 days of suckling had lost 31% and 8%, respectively, of their existing depots. In comparison to non-pregnant (dry) ewes, the endocrine profiles of late-pregnant ewes were characterised by low levels of cortisol and prolactin and high levels of progesterone and oestradiol. Lactating ewes had lower levels of cortisol and leptin and higher levels of prolactin compared to both dry and early-weaned ewes. The mobilisation of fat and protein reserves throughout lactation in suckled ewes was closely associated with leptin and cortisol profiles, and provided strong evidence of an underlying nutritional basis for the periparturient relaxation of immunity. Both leptin and cortisol concentrations were also associated with both parasite burden and the immune status of the ewe. It is suggested that lower blood cortisol levels in suckled ewes contribute to a Th1 biased immune response that leads to an increased susceptibility to gastrointestinal nematodes. The results provide a detailed characterisation of the physiology underlying the periparturient relaxation of immunity to T. colubriformis, from which further investigations will aim to expose potential causal factors.

Stress and immunity in wild vertebrates: timing is everything

Stress has profound effects on vertebrate immunity, but most studies have considered stress-immune interactions in terms of wild animals enduring demanding, but predictable activities (e.g., immune alterations during breeding). A growing biomedical literature, however, indicates that stress may not be obligatorily immunosuppressive; in response to transient, unpredictable stressors, immune activity can be enhanced, especially in body areas requiring immune protection. Also, immune sensitivity to stressors is not fixed throughout life; oftentimes, glucocorticoid (GC) insensitivity can be induced. Further GC sensitivity can be programmed early in life; greater exposure to stressors prior to maturity heightens GC effects on immunity in adulthood. In the present paper, I review the cellular and molecular mechanisms that link stress responses to immune adjustments over short time scales in domesticated species then I attempt to place stress-immune interactions in a naturalistic, organismal context. When, how and why stressors affect immunity in wild animals remains practically unstudied.

Effects of stress, mimicked by administration of corticosterone in drinking water, on the expression of chicken cytokine and chemokine genes in lymphocytes

In this study, we identify molecular mediators that participate in the regulation of the immune response during corticosterone-induced stress in chickens. At 7 weeks of age, 120 chickens were exposed for 1 week to corticosterone treatment. Cytokine and chemokine mRNA expression levels were evaluated in peripheral blood and splenic lymphocytes. Expression levels of interleukin (IL)-1beta, IL-6, IL-18 and transforming growth factor (TGF)-beta4 mRNA were significantly up-regulated in lymphocytes 3 h after first treatment with corticosterone. TGF-beta4 and IL-18 remained elevated 1 week post-initial treatment. Compared with controls, corticosterone-treated birds showed greater expression levels of chemokine (CC) mRNA, particularly for CCLi2, CCL5 (RANTES), CCL16 and CXCLi1, in peripheral and splenic lymphocytes 3 h post-initial exposure. CCLi2 mRNA was highly expressed in splenocytes at all time-points. Administration of corticosterone significantly increased circulating corticosterone concentrations and decreased total lymphocyte counts at 3, 24 h and 1 week post-initiation of corticosterone treatment. There was a positive correlation between plasma corticosterone concentrations and CCL5 and CCL16 mRNA at 3 h post-initial administration. At 1 week post-initial treatment, corticosterone concentrations correlated positively with CCL5 and negatively with IL-18 mRNA level. Conditions associated with significant changes in corticosterone levels might therefore affect the immune response by increasing pro-inflammatory responses, leading to potential modulation of the Th1/Th2 balance.

Distributions of glucocorticoid receptor gene polymorphisms in a Chinese Han population and associations with outcome after major trauma

AIM

To investigate in a Chinese population the occurrence of polymorphisms Bcl I, N363S and ER22/23EK in the glucocorticoid receptor and their association with outcome of trauma.

METHODS

In all, 266 healthy volunteers and 95 victims of major trauma were recruited. The presence of glucocorticoid receptor polymorphisms (ER22/23EK, N363S and Bcl I) was sought by restriction fragment length polymorphism analysis. The injured group were monitored as to respiratory, renal, hepatic, cardiovascular, haematological and central nervous functions. The association was determined between polymorphisms and the development of multiple organ dysfunction syndrome and sepsis after trauma.

RESULTS

Only the Bcl I polymorphism was identified. The frequency of its G allele was 23.5% among volunteers and 26.3% among casualties. There were no significant differences in MOD score or sepsis rate between participants classified according to genotype.

CONCLUSIONS

Only the Bcl I polymorphism of the glucocorticoid receptor gene is common in the Chinese Han population; it may not influence the development of complications following major trauma.

High resolution melting (HRM) analysis for the detection of ER22/23EK, BclI, and N363S polymorphisms of the glucocorticoid receptor gene

Polymorphisms in the glucocorticoid receptor (GR) gene have been associated with altered sensitivity to glucocorticoids. We designed a high-resolution melting (HRM) assay to detect, simultaneously, the three most intriguing GR polymorphisms, selected on the bases of clinical relevance and frequencies in caucasian population as described in literature. HRM enables the detection of ER22/23EK and N363S genotypes but fails to discriminate homozygous mutant for the BclI polymorphism from wild-type samples, however a simple spike experiment leads to a clear discrimination between these genotypes. The analyses were performed on a cohort of 70 healthy Caucasian subjects. The method was validated by restriction fragment length polymorphisms; HRM results were found to be in 100% concordance with those observed with the restriction enzymes. We also employed this method on a population of 40 Crohn Disease patients; the analysis demonstrated a significantly higher frequency of the BclI polymorphism in patients than in healthy volunteers. This is, at now, the less expensive and time-and work-saving method to detect GR mutations, providing precision, fast screening and high throughput capabilities.

Infection as a stressor: a cytokine-mediated activation of the hypothalamo-pituitary-adrenal axis?

Infections are associated with increased plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone. Hypothalamo-pituitary-adrenal (HPA) responses have also been observed with immunological stimuli that are not infective. Although such responses have been suggested to be mediated by ACTH secreted by lymphocytes, adrenocortical activation by immunological stimuli requires a functional pituitary. The most likely mechanism by which immunological stimuli activate the HPA axis involves production of cytokines by lymphocytes. The prime candidate is interleukin 1 (IL-1), because IL-1 production follows activation of the immune system and IL-1 administration is a potent activator of the HPA axis. However, other cytokines, such as tumour necrosis factor, may also be involved. Most immunological stimuli and IL-1 also activate both peripheral and central noradrenergic neurons. IL-1-induced activation of the HPA axis in vivo depends upon secretion of corticotropin-releasing factor (CRF), an intact pituitary, and the ventral noradrenergic bundle which innervates the CRF-containing neurons in the paraventricular nucleus (PVN) of the hypothalamus. Besides elevating body temperature, administration of IL-1 elicits a number of behavioural responses in rats and mice, including anorexia, increased sleep time, decreased investigation of novel objects and other animals, increased defensive withdrawal and other behaviours characteristic of sickness. Some of these responses can be reversed by CRF-antagonists and mimicked by CRF administration. Thus, endogenous production of IL-1 can account for a range of physiological and behavioural responses characteristic of sickness. Nevertheless, definitive evidence that IL-1 mediates these responses in sick animals is lacking.

Salivary cortisol and DHEA levels in the Korean population: age-related differences, diurnal rhythm, and correlations with serum levels

PURPOSE

The primary objective of this study was to examine the changes of basal cortisol and DHEA levels present in saliva and serum with age, and to determine the correlation coefficients of steroid concentrations between saliva and serum. The secondary objective was to obtain a standard diurnal rhythm of salivary cortisol and DHEA in the Korean population.

MATERIALS AND METHODS

For the first objective, saliva and blood samples were collected between 10 and 11 AM from 359 volunteers ranging from 21 to 69 years old (167 men and 192 women). For the second objective, four saliva samples (post-awakening, 11 AM, 4 PM, and bedtime) were collected throughout a day from 78 volunteers (42 women and 36 men) ranging from 20 to 40 years old. Cortisol and DHEA levels were measured using a radioimmunoassay (RIA).

RESULTS

The morning cortisol and DHEA levels, and the age- related steroid decline patterns were similar in both genders. Serum cortisol levels significantly decreased around forty years of age (p < 0.001, when compared with people in their 20s), and linear regression analysis with age showed a significant declining pattern (slope=-2.29, t=-4.297, p < 0.001). However, salivary cortisol levels did not change significantly with age, but showed a tendency towards decline (slope=-0.0078, t=-0.389, p=0.697). The relative cortisol ratio of serum to saliva was 3.4-4.5% and the ratio increased with age (slope=0.051, t=3.61, p < 0.001). DHEA levels also declined with age in saliva (slope=-0.007, t=-3.76, p < 0.001) and serum (slope=-0.197 t=-4.88, p < 0.001). In particular, DHEA levels in saliva and serum did not start to significantly decrease until ages in the 40s, but then decreased significantly further at ages in the 50s (p < 0.001, when compared with the 40s age group) and 60s (p < 0.001, when compared with the 50 age group). The relative DHEA ratio of serum to saliva was similar throughout the ages examined (slop=0.0016, t=0.344, p=0.73). On the other hand, cortisol and DHEA levels in saliva reflected well those in serum (r=0.59 and 0.86, respectively, p < 0.001). The highest salivary cortisol levels appeared just after awakening (about two fold higher than the 11 AM level), decreased throughout the day, and reached the lowest levels at bedtime (p < 0.001, when compared with PM cortisol levels). The highest salivary DHEA levels also appeared after awakening (about 1.5 fold higher than the 11 AM level) and decreased by 11 AM (p < 0.001). DHEA levels did not decrease further until bedtime (p=0.11, when compared with PM DHEA levels).

CONCLUSION

This study showed that cortisol and DHEA levels change with age and that the negative slope of DHEA was steeper than that of cortisol in saliva and serum. As the cortisol and DHEA levels in saliva reflected those in serum, the measurement of steroid levels in saliva provide a useful and practical tool to evaluate adrenal functions, which are essential for clinical diagnosis.

Effects of arginine-vasopressin and parathyroid hormone-related protein (1-34) on cell proliferation and production of YKL-40 in cultured chondrocytes from patients with rheumatoid arthritis and osteoarthritis

OBJECTIVE

Both arg-vasopressin (AVP) and parathyroid hormone-related protein (PTHrP) may act as proinflammatory hormones. In addition, they have been suggested to be involved in the pathophysiology of rheumatoid arthritis (RA). We therefore investigated the effects of AVP and PTHrP (1-34) on cell proliferation and secretion of the glycoprotein YKL-40 in human chondrocytes derived from healthy subjects as well as from patients with RA or osteoarthritis (OA).

METHOD

Primary cultures of human chondrocytes were incubated with AVP (1-100 pmol/l) or PTHrP (1-34) (0.1-100 nmol/l). Cell proliferation was measured as [3H]thymidine incorporation. Intracellular cAMP and YKL-40 in cell medium were determined by commercially available kits.

RESULTS

AVP and PTHrP (1-34) increased proliferation in chondrocytes derived from healthy donors as well as from RA and OA patients. PTHrP (1-34), but not AVP, increased intracellular levels of cAMP. PTHrP (1-34) did not change the amount of YKL-40 in chondrocytes from healthy subjects or patients with OA. AVP tended to decrease the secretion of YKL-40 from healthy chondrocytes. Both PTHrP (1-34) and AVP increased YKL-40 secretion from RA chondrocytes. In contrast, AVP decreased the secretion of YKL-40 in chondrocytes from patients with OA.

CONCLUSION

AVP and PTHrP (1-34) stimulated proliferation in human chondrocytes derived from healthy subjects as well as from patients with RA or OA. However, the effects of AVP and PTHrP (1-34) on YKL-40 secretion varied depending on the origin of the chondrocytes.

Effect of chronic clenbuterol administration and exercise training on immune function in horses

Effects of longitudinal exercise training and acute intensive exercise (simulated race test) on immune function have not been reported in horses. Clenbuterol, a beta2-adrenergic agonist, is used to manage inflammatory airway disease in horses. This study investigated the interaction of 8 wk of exercise training with or without 12 wk of clenbuterol administration in horses. Twenty-three untrained standardbred mares (10 +/- 3 yr, Mean +/- SE) were used and divided into four experimental groups. Horses given clenbuterol plus exercise (CLENEX; n = 6) and clenbuterol alone (CLEN; n = 6) received 2.4 microg/kg BW of clenbuterol twice daily (in an average volume of 20 mL) on a schedule of 5 d on and 2 d off for 12 wk. The CLENEX group was also aerobically trained 3 d/wk. Mares given exercise alone (EX; n = 5) were aerobically trained for 3 d/wk, and the control group (CON; n = 6) remained sedentary. Both EX and CON horses were administered similar volumes (approximately 20 mL) of molasses twice daily. A simulated race test (SRT) resulted in an elevation in lymphocyte number postexercise (P < 0.05). There was no significant difference after acute exercise in either monocyte or granulocyte number. Acute exercise resulted in a decrease (P < 0.05) in the percentage of CD4+ and an increase (P < 0.05) in the percentage of CD8+ cells. The SRT resulted in a decreased lymphoproliferative response to pokeweed mitogen (P < 0.05). A SRT had no effect on antibody production in response to equine influenza vaccine. The EX group demonstrated greater cortisol concentrations at rest and at all other time points postexercise after completing the training regimen compared with CLENEX horses (P < 0.05). Preexercise (SRT) peripheral blood monocyte number was lower in CLENEX horses than in other treatment groups (P < 0.05). Clenbuterol and exercise training did not significantly affect post-SRT changes in leukocyte numbers. Exercise training resulted in a decrease (P < 0.05) in the percentage of CD8+ cells post-SRT compared with other groups, but the percentage of CD4+ cells was not altered by either clenbuterol or exercise conditioning. Lymphocyte proliferative response was not affected by clenbuterol or exercise treatment. Horses demonstrated responses to bouts of acute exercise as noted with other species, namely humans and rodents.

T-cell function after interleukin-2 therapy in HIV-infected patients is correlated with serum cortisol concentrations

OBJECTIVES

To examine the effects of interleukin (IL)-2 therapy on in-vitro lymphocyte responsiveness in HIV-infected patients and to correlate these data with serum cortisol concentrations.

DESIGN

German prospective study.

METHODS

In adult patients (n = 32) treated with 9 x 10(6) IU/day interleukin-2, lymphocyte transformation tests (LTT), serum cortisol concentrations and CD4 T-cell counts were assessed before, during and after IL-2 therapy.

RESULTS

A significant decrease in responses towards mitogens and recall antigens (P < 0.05) was observed on day 7 after starting a 4- to 5-day IL-2 therapy as compared to baseline. Serum cortisol levels increased (P < 0.0001) reaching a maximum on day 4, and were still elevated on day 7 (P < 0.005). CD4 T-cell counts significantly decreased with a minimum on day 2 before increasing 2.4-fold above baseline on day 7 (P < 0.005 each). A positive correlation (P < 0.05 each) was observed for changes in cortisol levels and in LTT mitogen and antigen reactions (both day 7 - 0), changes in cortisol levels (day 3 - 0) and CD4 cell counts on day 2, and corticotrophin releasing hormone test results and LTT antigen reactions on day 7. LTT responses, cortisol levels and CD4 T-cell counts returned to baseline on day 30.

CONCLUSION

Serum cortisol concentrations are predictive of functional and numerical changes of T cells induced by IL-2 therapy.

Effect of Duration of Cold Stress on Plasma Adrenal and Thyroid Hormone Levels and Immune Responses in Chicken Lines Divergently Selected for Antibody Responses

There is increasing evidence that stress affects various immune processes. Some of these changes are due to hormonal changes involving corticosterone (CORT), triiodothyronine (T3), and thyroxine (T4). Effects of stress depend on the nature of specific stressors (e.g., thermal extremes, diet, pollutants), and stress-modifiers (e.g., genetic make-up, duration and severity of the stressors). We studied the effects of a specific stress (cold stress) with stress-modifiers (duration of stress and genotype of the bird) on immune responses and plasma adrenal and thyroid hormone levels in 3 layer-type chicken lines. Two lines were divergently selected for high (H line) or low (L line) antibody responses to SRBC, and the third line was a randombred control (C) line. Growing chicks (3- to 4-wk-old) of the 3 lines were feed-restricted at 80% of ad libitum consumption, and subjected to cold stress (CS) at 10 degrees C continuously for 7, 5, 3, 1, or 0 d before immunization with keyhole limpet hemocyanin (KLH). Specific antibody titers to KLH, and in vitro lymphocyte proliferation (LP) upon mitogen stimulation were measured. In addition, adrenal and thyroid hormone levels were measured in the plasma samples collected at the end of CS. No significant effect of duration of CS on specific antibody titers was found in the 3 lines. A significant enhancing effect of CS was found on LP. A significant dose-dependent suppressive effect of CS was found on plasma CORT levels. One day of CS had a significant enhancing effect on T3 levels. There was no significant effect of duration of CS on T4 levels. We conclude that CS does not affect specific antibody responses, but may have a modulating effect on cellular immunity and plasma CORT levels, depending on the duration of the stress. The present study suggests an inverse relationship between LP and CORT. This is the first study that reveals an absence of significant differences in adrenal and thyroid hormone levels in the described selection lines.

Association of proinflammatory molecules with apoptotic markers and survival in critically ill multiple organ dysfunction patients

Recent evidence supports the involvement of apoptosis in multiple organ dysfunction (MODS). The authors examined the hypothesis that nitric oxide (NO), interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and cortisol correlate with Fas and Fas ligand (FasL) expression on peripheral blood mononuclear cells and that Fas and FasL, therefore, mediate their association with MODS severity. Thirty-five critically ill adult MODS patients were followed for up to 14 days and were compared to non-MODS matched controls. Fas, FasL, nitrate, cortisol, and IL-6 were elevated in MODS patients (P < 0.05). Nitrate and cortisol correlated with Fas expression (P < 0.05). All factors studied, except for TNF-alpha, correlated with MODS severity (P < 0.05); however, by multivariate analyses, Fas and FasL were independently associated with severity and survival (P < 0.05). The inflammatory molecules studied may mediate the association of apoptotic constituents with MODS severity and survival only in part.

Opposing effects of short- and long-term stress on airway inflammation

Between 20% and 35% of subjects with asthma experience asthma exacerbations during periods of stress. The biological mechanisms underlying these exacerbations are not clearly understood, and the role of psychologic factors in the pathophysiology of asthma remains controversial. We investigated the ability of psychologic stress to modulate airway inflammation and airway hyperresponsiveness (AHR) to methacholine in a murine model of asthma. Animals were exposed to a stressor daily for 3 (short-term stress) or 7 (long-term stress) days. After allergen challenge, AHR was assessed through plethysmography, and bronchoalveolar lavage cells were counted as a measure of inflammation. After short-term stress, inflammatory cell number was decreased compared with unstressed animals, whereas levels of interleukin (IL)-6, IL-9, and IL-13 were increased. Administration of a corticosteroid receptor antagonist, before stress, prevented the decrease in inflammatory cell numbers. In contrast, animals stressed for 7 consecutive days showed a significant increase in inflammatory cell numbers, which was independent of the glucocorticoid response, but no change in cytokine levels. AHR was not altered in stressed animals. Our results indicate that repeated exposure to stress over the long term engages different mechanisms than short-term stress and can exacerbate the chronic inflammatory responses of the airway.

No detrimental effect from chronic exposure to buprenorphine on corticosteroid-binding globulin and corticosensitive immune parameters

Opioid drugs reportedly regulate the immune system via their effects on the hypothalamic- pituitary-adrenal (HPA) axis. The present study was carried out to assess the effects of chronic exposure to buprenorphine on HPA axis activation, corticosteroid-binding globulin (CBG), the main glucocorticoid (GC) carrier, and the immune system. Results show that buprenorphine, delivered by osmotic pump subcutaneously in C57BL/6 male mice during a 10-day period, caused a marked decrease in total corticosterone (CORT) levels at day 1 of exposure. CORT levels then increased with maximal values observed at day 5 of exposure. After day 5, total CORT levels gradually decreased and returned to control values. No significant changes were observed in CBG protein levels and mRNA expression in the liver. Since CBG levels remained unchanged, the percentage of free CORT values in buprenorphine mice did not differ from control values. Thus, the variations observed in the amount of free CORT were related only to changes measured in total CORT. These endocrine changes did not have a significant impact on the immune parameters measured. Total CD(4)+ and CD(8)+ splenic and thymic populations were not modulated by buprenorphine. However, splenocytes from mice exposed to buprenorphine after 5 days exhibited greater proliferation upon anti-TCR monoclonal antibody stimulation than saline-exposed mice. These results indicate that buprenorphine can be safely used because it did not have significant effects on GC availability for immune corticosensitive cells.

Stressed to death: implication of lymphocyte apoptosis for psychoneuroimmunology

Psychological and physical stressors best exemplify the intercommunication of the immune and the nervous systems. It has been shown that stress significantly impacts leukocyte cellularity and immune responses and alters susceptibility to various diseases. While acute stress has been shown to enhance immune responses, chronic stress often leads to immunosuppression. Among many criteria examined upon exposure to chronic stress, the reduction in lymphocyte mitogenic response and lymphocyte cellularity are commonly assessed. We have reported that chronic restraint stress could induce lymphocyte reduction, an effect dependent on endogenous opioids. Interestingly, the effect of endogenous opioids was found to be exerted through increasing the expression of a cell death receptor, Fas, and an increased sensitivity of lymphocytes to apoptosis. Stress-induced lymphocyte reduction was not affected by adrenalectomy. In this review, based on available literature and our recent data, we will discuss the role of the hypothalamic-pituitary-adrenal axis and endogenous opioids and examine the mechanisms by which chronic stress modulates lymphocyte apoptosis.

Influence of restraint stress on ligature-induced periodontitis in rats

The influence of stress on periodontal breakdown in Wistar rats was analyzed during experimental periodontitis, induced by placing silk ligatures around the maxillary right second molar teeth. The rats were divided into three groups with 10 animals in each; the first group was exposed to restraint stress for 12 h d(-1) for a period of 4 wk; the second group was exposed to restraint stress for 2.5 h d(-1) for a period of 4 wk; the third group served as a control group. Ligation for 4 wk resulted in an accelerated periodontal degradation, whereas the restraint stress by itself had no significant effect. Combined stress and ligation resulted in a significantly higher attachment loss and alveolar bone resorption than either treatment alone, while no differences were seen between the two stress regimens. After 4 wk, a reduced body weight was found in both restrained groups of rats and a reduced weight of the thymus in the rats restrained for 12 h d(-1), while no changes were observed in the weight or composition of the suprarenal glands. We conclude that stress alone does not result in periodontal disease but may modulate the pathophysiological processes of already present periodontal inflammation, resulting in accelerated degradation of periodontal tissues.

Acute stress enhances while chronic stress suppresses skin immunity. The role of stress hormones and leukocyte trafficking

Delayed-type hypersensitivity (DTH) reactions are antigen-specific, cell-mediated immune responses that, depending on the antigen, mediate beneficial (resistance to viruses, bacteria, fungi) or harmful (allergic dermatitis, autoimmunity) aspects of immunity. Contrary to the widely held notion that stress is immunosuppressive, we have shown that under certain conditions, stress can enhance immune function. DTH reactions can be studied in rats or mice by challenging the pinnae of previously sensitized animals with antigen. Studies have shown that acute stress administered immediately before antigen exposure significantly enhances skin DTH. In contrast, chronic stress significantly suppresses skin DTH. Stress-induced changes in leukocyte distribution may contribute to these bidirectional effects of stress, since acute stress induces a significant mobilization of leukocytes from the blood to the skin, whereas chronic stress suppresses leukocyte mobilization. In order to identify the hormonal mediators of the observed effects of stress, we first showed that adrenalectomy (ADX) eliminates the stress-induced enhancement of DTH. Acute administration (to ADX animals) of low doses of corticosterone and/or epinephrine significantly enhances skin DTH. In contrast, acute administration of high doses of corticosterone, low doses of dexamethasone, or chronic administration of moderate doses of corticosterone, suppress skin DTH. Thus, the timing and duration of stress may significantly affect the nature (enhancing versus suppressive) of the effects of stress on skin immune function. These results suggest that during acute stress, stress hormones may help enhance immune function by informing the immune system about impending challenges (e.g., wounding or infection) that may be imposed by a stressor (e.g., an aggressor). Thus, during acute stress, the brain may send a warning signal to the immune system, just as it does to other fight/flight systems in the body.

Acute exercise effects on the immune system

PURPOSE

In recent years, health professionals have placed increased attention on the benefits of physical activity for maintaining health in the general population as well as regaining health in many disease states. Conversely, reports of apparent decreases in immune cell function after acute exercise are widespread in the literature. The purpose of this article is to evaluate critically the available data and currently employed methods, with the aim of establishing whether genuine or artefactual alterations of immune function are being reported. During and immediately after exercise, the total number of white blood cells in peripheral blood samples increases, such that the relative proportions of cell types within the leukocyte pool are altered. A number of important areas of discussion arise from these shifts in the number of circulating cells after exercise, not least of which is the artefactual effects they may have on currently employed assays of immune cell function. Recent advances in methodology are beginning to call into question the assumption that acute exercise has any genuine immunosuppressive effect.

CONCLUSION

At present, there is little evidence to suggest that the range of acute exercise intensities and durations recommended by ACSM has a major detrimental effect on the function of individual T- and B-lymphocytes, natural killer cells and neutrophils. Although individual cells may not be as adversely affected as previously supposed, it is unclear whether the numerical content of the circulating population is an important clinical consideration.