Increased concentrations of interleukin 1-beta in whole blood cultures supernatants after 12 weeks of moderate endurance exercise

Immunology of Physical Exercise: Is Equus caballus an Appropriate Animal Model for Human Athletes?

Domestic horses routinely participate in vigorous and various athletic activities. This enables the horse to serve as a model for studying athletic physiology and immunology in other species, including humans. For instance, as a model of physical efforts, such as endurance rides (long-distance running/aerobic exercise) and races (anaerobic exercise), the horse can be useful in evaluating post-exercise response. Currently, there has been significant interest in finding biomarkers, which characterize the advancement of training and adaptation to physical exercise in the horse. The parallels in cellular responses to physical exercises, such as changes in receptor expression and blood cell activity, improve our understanding of the mechanisms involved in the body's response to intense physical activity. This study focuses on the changes in levels of the pro- and anti-inflammatory cytokines and cellular response in the context of post-exercise immune response. Both the direction of changes in cytokine levels and cellular responses of the body, such as proliferation and expression of surface markers on lymphocytes, monocytes and neutrophils, show cross-functional similarities. This review reveals that horses are robust research models for studying the immune response to physical exercise in human athletes.

Interpreting 'anti-inflammatory' cytokine responses to exercise: focus on interleukin-10

Circulating concentrations of canonically pro- and anti-inflammatory cytokines are commonly measured when evaluating the anti-inflammatory effects of exercise. An important caveat to interpreting systemic cytokine concentrations as evidence for the anti-inflammatory effects of exercise is the observed dissociation between circulating cytokine concentrations and cytokine function at the tissue/cellular level. The dichotomization of cytokines as pro- or anti-inflammatory also overlooks the context dependence of cytokine function, which can vary depending on the physiological state being studied, the cytokine's cellular source/target, and magnitude of cytokine responses. We re-evaluate our current understanding of anti-inflammatory cytokine responses to exercise by highlighting nuances surrounding the interpretation of altered systemic cytokine concentrations as evidence for changes in inflammatory processes occurring at the tissue/cellular level. We highlight the lesser known pro-inflammatory and immunostimulatory actions of the prototypical anti-inflammatory cytokine, interleukin (IL)-10, including the potentiation of interferon gamma production during endotoxaemia, CD8⁺ T cell activation in tumour bearing rodents and cancer patients in vivo, and CD8⁺ T lymphocyte and natural killer cell activation in vitro. IL-10's more well-established anti-inflammatory actions can also be blunted following exercise training and under chronic inflammatory states such as type 2 diabetes (T2D) independently of circulating IL-10 concentrations. The resistance to IL-10's anti-inflammatory action in T2D coincides with blunted STAT3 phosphorylation and can be restored with small-molecule activators of IL-10 signalling, highlighting potential therapeutic avenues for restoring IL-10 action. We posit that inferences based on altered circulating cytokine concentrations alone can miss important functional changes in cytokine action occurring at the tissue/cellular level.

Changes in the levels of IL-1β, cortisol and chromogranin A in saliva of subjects with occupational fatigue

Changes in the levels of interleukin-1β (IL-1β), cortisol and chromogranin A (CgA) in saliva of subjects with occupational fatigue were investigated. Doctors in the Emergency Department were selected as research subjects. Saliva was collected before work (after full rest) and after work (≥24 h). Electroencephalogram (EEG) was performed. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of IL-1β, cortisol and CgA in saliva. In order to obtain permission for human specimens, the study was approved by the Ethics Committee of the Affiliated Hospital of Hebei University of Engineering and registered for clinical trials (registration no. ChiC-TR-DCD-14005746). As there were only 4 subjects in this study without fatigue waves in EEG, and the number of these subjects was not sufficient to constitute a control group, the comparison of the contents of IL-1β, cortisol and CgA of all subjects before and after working for 18 h was just a confirmation of the statistical results of 43 cases with fatigue waves in the EEG. According to the results, there was no change in the contents of IL-1β and cortisol in the saliva of subjects with occupational fatigue before and after fatigue, whereas, there was a significant change in the content of CgA before and after fatigue. However, there was no correlation between the content of CgA and fatigue. The results of the present study revealed that IL-1β, cortisol and CgA indicators are not suitable diagnostic markers for occupational fatigue.

Exercise-induced cytokine changes in antigen stimulated whole-blood cultures compared to serum

Strenuous exercise is followed by an elevation of many cytokines with inflammation regulating properties. Since most cytokines act at pico- or nanomolar concentrations many investigations failed to detect their concentrations in vivo. Hence, the aim of this study was to evaluate the significance of cytokine measurements (IL-1β, TNF-α, IL-1ra, IL-6, CCL2 and CXCL8) in a stimulated whole-blood culture (sWBC) compared to serum with respect to their exercise-induced kinetics and detection rates. 40 male volunteers (age: 25,5±4,3years, BMI: 24,00±2,24, VO₂peak: 46,9±4,1mL/kg×min) performed 60min of intensive bicycle exercise (80% VO₂peak). Blood samples were taken before and for up to 24h after exercise. All cytokines were determined by a multiplex ELISA. There were weak to moderate correlations between cytokines in sWBC and serum. While exercise did not affect pro-inflammatory cytokines in serum, in sWBC only IL-1β was increased 1.2-fold at 3h (p<0,05). All other cytokines increased both in sWBC and serum. The detection rate was superior in sWBC vs serum for most cytokines. Exercise-induced cytokine kinetics in sWBC do not reflect systemic changes. Both approaches provide a synergistic insight into inflammatory processes on the cytokine level.

A model of human whole blood lymphokine release for in vitro and ex vivo use

Endotoxin (lipopolysaccharide, LPS) inducible cytokine release by human whole blood is increasingly used to model inflammatory responses in vitro, to detect the presence of pyrogenic contaminations as well as to monitor disease states or immunomodulatory treatments ex vivo. However, the LPS-stimulated blood model primarily allows the assessment of monocyte responses. Here, a whole blood model was established which allows assessment of lymphocyte responses. Four different superantigens, namely staphylococcal enterotoxin A and B (SEA, SEB), toxic shock syndrome toxin-1 (TSST-1) or streptococcal exotoxin A (SPEA) were tested with respect to the induction of lymphokine release. All superantigens were capable of inducing significant amounts of the lymphokines interferon-gamma (IFNgamma), interleukin 2 (IL-2), IL-4, IL-5, IL-13 and tumor necrosis factor beta (TNFbeta) after 72 h of incubation. Concentration-dependencies and kinetics were determined. Blood from 160 healthy donors was used to assess the variability of SEB-inducible lymphokine release. Interindividual differences were more pronounced compared to LPS-inducible monokine release. However, the individual response was maintained when blood from six donors was tested once a week for 8 weeks, suggesting that the individual response represents a donor characteristic. The model appears to be suitable for the evaluation of immunomodulatory agents in vitro as well as ex vivo.

Antioxidants attenuate the plasma cytokine response to exercise in humans

Exercise increases plasma TNF-alpha, IL-1beta, and IL-6, yet the stimuli and sources of TNF-alpha and IL-1beta remain largely unknown. We tested the role of oxidative stress and the potential contribution of monocytes in this cytokine (especially IL-1beta) response in previously untrained individuals. Six healthy nonathletes performed two 45-min bicycle exercise sessions at 70% of Vo(2 max) before and after a combination of antioxidants (vitamins E, A, and C for 60 days; allopurinol for 15 days; and N-acetylcysteine for 3 days). Blood was drawn at baseline, end-exercise, and 30 and 120 min postexercise. Plasma cytokines were determined by ELISA and monocyte intracellular cytokine level by flow cytometry. Before antioxidants, TNF-alpha increased by 60%, IL-1beta by threefold, and IL-6 by sixfold secondary to exercise (P < 0.05). After antioxidants, plasma IL-1beta became undetectable, the TNF-alpha response to exercise was abolished, and the IL-6 response was significantly blunted (P < 0.05). Exercise did not increase the percentage of monocytes producing the cytokines or their mean fluorescence intensity. We conclude that in untrained humans oxidative stress is a major stimulus for exercise-induced cytokine production and that monocytes play no role in this process.

Production of monokines in patients under polysulphone haemodiafiltration is influenced by the ultrafiltration flow rate

BACKGROUND

Chronic haemodialysis patients show various clinical signs of immunodeficiency and there is growing evidence that a dysregulated monocyte cytokine production is heavily involved in this deficiency. The production of monokines in vitro has been proposed to correlate closely with the in vivo immune status and to be of high clinical relevance in cuprophane haemodialysis. Even though it is well known that the biocompatibility of dialyser membranes has a significant impact on immune functions, little is known about the influence of the ultrafiltration flow rate (UFR). The aim of this study was to investigate the potential long-term effects of UFR on the production of interleukin-10 (IL-10), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in an intra-individual study design.

METHODS

In 11 patients previously treated with polysulphone haemodiafiltration, UFR was reduced from 40-46 ml/min to 24-28 ml/min, then to 7-10 ml/min before it was reinstated at 40-46 ml/min for periods of 4 weeks each. Monokine secretion into culture supernatants and mRNA expression (assessed using a novel Taqman PCR technique), were determined in a whole blood assay after lipopolysaccharide stimulation.

RESULTS

Reduction of UFR led to a significant increase in IL-10 secretion and mRNA expression (P=0.012, P=0.001). Conversely, a substantial (but not complete) decrease was observed when UFR returned to initial levels. In contrast, supernatant concentrations of IL-1beta (P=0.04) and IL-6 (P=0.003), and mRNA expression of both monokines (P<0.001, P<0.001) decreased significantly when UFR was reduced. Calculation of the IL-1beta/IL-10 ratio also revealed a decrease when UFR was reduced, with an increase again being observed when the initial degree of UFR was reinstated (P<0.001).

CONCLUSIONS

These results indicate a significant impact of UFR on the production of monokines at both the transcriptional and the protein level. We suggest that middle molecule removal has to be considered as a possible pathophysiological mechanism to explain our findings. Since monokine production in vitro was shown to be closely correlated with the in vivo immune status in patients on cuprophane haemodialysis, further investigations are necessary to clarify the impact of UFR on the immunocompetence of patients under polysulphone haemodiafiltration.

Stress-induced changes in skin barrier function in healthy women

Despite clear exacerbation of several skin disorders by stress, the effect of psychologic or exertional stress on human skin has not been well studied. We investigated the effect of three different stressors, psychologic interview stress, sleep deprivation, and exercise, on several dermatologic measures: transepidermal water loss, recovery of skin barrier function after tape stripping, and stratum corneum water content (skin conductance). We simultaneously measured the effects of stress on plasma levels of several stress-response hormones and cytokines, natural killer cell activity, and absolute numbers of peripheral blood leukocytes. Twenty-five women participated in a laboratory psychologic interview stress, 11 women participated in one night of sleep deprivation, and 10 women participated in a 3 d exercise protocol. The interview stress caused a delay in the recovery of skin barrier function, as well as increases in plasma cortisol, norepinephrine, interleukin-1beta and interleukin-10, tumor necrosis factor-alpha, and an increase in circulating natural killer cell activity and natural killer cell number. Sleep deprivation also decreased skin barrier function recovery and increased plasma interleukin-1beta, tumor necrosis factor-alpha, and natural killer cell activity. The exercise stress did not affect skin barrier function recovery, but caused an increase in natural killer cell activity and circulating numbers of both cytolytic T lymphocytes and helper T cells. In addition, cytokine responses to the interview stress were inversely correlated with changes in barrier function recovery. These results suggest that acute psychosocial and sleep deprivation stress disrupts skin barrier function homeostasis in women, and that this disruption may be related to stress-induced changes in cytokine secretion.

The cytokine response to physical activity and training

Cytokines are soluble glycoproteins that are produced by and mediate communication between and within immune and nonimmune cells, organs and organ systems throughout the body. Pro- and anti-inflammatory mediators constitute the inflammatory cytokines, which are modulated by various stimuli, including physical activity, trauma and infection. Physical activity affects local and systemic cytokine production at different levels, often exhibiting striking similarity to the cytokine response to trauma and infection. The present review examines the cytokine response to short term exercise stress, with an emphasis on the balance between pro- and anti-inflammatory mechanisms and modulation of both innate and specific immune parameters through cytokine regulation. The effects of long term exercise on cytokine responses and the possible impact on various facets of the immune system are also discussed, with reference to both cross-sectional and longitudinal studies of exercise training. Finally, the validity of using exercise as a model for trauma and sepsis is scruti- nised in the light of physiological changes, symptomatology and outcome, and limitations of the model are addressed. Further studies, examining the effect of exercise, trauma and infection on novel cytokines and cytokine systems are needed to elucidate the significance of cytokine regulation by physical activity and, more importantly, to clarify the health implications of short and long term physical activity with respect to overall immune function and resistance to infection.