Moderate and exhaustive endurance exercise influences the interferon-gamma levels in whole-blood culture supernatants

Effect of 2 weeks rest-pause on oxidative stress and inflammation in female basketball players

Intense exercise leads to increased production of free radicals, resulting in an inflammatory response in athletes. For this reason, it was decided to investigate whether a single intensive exercise until exhaustion applied after a 2-week rest period would result in a violation of the pro-oxidant-antioxidant balance. Twenty-seven trained female basketball players (age: 16.55 ± 0.96 years, body mass: 66.40 ± 13.68 kg, height: 173.45 ± 5.14 cm) were enrolled to the study following the application of inclusion and exclusion criteria. Study was conducted at the end of the competitive training phase. Participants underwent incremental treadmill exercise, with blood samples collected before the test, immediately post-exercise, and after a 3-h restitution period. Total antioxidant capacity (TAC) levels increased significantly after exercise and remained unchanged after 3 h. Concentration of interleukin-10 (IL-10) and creatine kinase (CK) significantly increased after exercise and then decreased. Concentration of interleukin-2 (IL-2) was significantly reduced immediately and 3 h after exercise, while interleukin-13 (IL-13), interleukin-1α (IL-1α), and tryptophan (TRP) decreased 3 h after exercise. No significant changes were observed in other biochemical parameters. Obtained results show an increased antioxidant capacity which reduced oxidative stress and inflammation in response to intense exercise indicating that rested athletes have a high adaptation and elevated tolerance to effort.

Metabolic and immune/inflammatory alterations induced by a triathlon under extreme conditions

Purpose

To investigate the effects of triathlon racing under extreme conditions on metabolic and immune/inflammatory responses.

Methods

Thirteen amateur athletes participated in an extreme triathlon competition (swim – 3.8 km; cycling – 180 km; running – 4 2 km; with a 3,700 m accumulated altitude). Blood samples were collected on three different occasions: pre-competition (baseline), immediately post-competition (IM), and 12 h post-competition (12 h) to evaluate glycemic and lipid profiles, leukocytes count, and cytokines levels in plasma and in whole-blood cell culture supernatant stimulated or not with LPS.

Results

Decreased glucose and triglycerides levels, increased LDL, and a significant leukocytosis were observed at IM and 12 h compared to baseline. In addition, higher serum levels of IL-6, IL-8, and IL-10 were found at IM than in baseline and post-12 h. Whereas increased IL-12p40 levels were observed for 12 h compared to baseline. At baseline, in LPS-stimulated cell culture, IL-6, IL-8, and IL-12p70 were higher, while IL-12p40 levels were lower than non-stimulated cell culture. At IM, IL-12p40 levels were unchanged, while higher levels of other cytokines were found in LPS-stimulated cell culture compared to non-stimulated cell culture. The 12 h results showed higher levels of IL-6, IL-8, and IL-10 in LPS-stimulated cell culture than in non-stimulated cell culture. Additionally, a significant negative correlation between circulating glucose levels and IL-6 was found.

Conclusion

The triathlon competition's performance under extreme conditions has remarkable impacts on the lipid profile and systemic immune/inflammatory responses. For the first time, significant alterations in the cytokine responses of whole blood cell culture to LPS-stimulation in baseline, IM, and 12h were demonstrated.

Sedentary behavior, exercise and COVID-19: immune and metabolic implications in obesity and its comorbidities

Many reports showed a dramatic decrease in the levels of physical activity during the current pandemic of SARS-CoV-2. This has substantial immune and metabolic implications, especially in those at risk or with metabolic diseases including individuals with obesity and Type 2 diabetes. In this study we discussed the route from physical inactivity to immune and metabolic aberrancies; focusing on how insulin resistance could represent an adaptive mechanism to the low physical activity levels and on how such an adaptive mechanism could shift to a pathognomonic feature of metabolic diseases, creating a vicious circle of immune and metabolic aberrancies. We provide a theoretical framework to the severe immunopathology of COVID-19 in patients with metabolic diseases. We finally discuss the idea of exercise as a potential adjuvant against COVID-19 and emphasize how even interrupting prolonged periods of sitting with short time breaks of very light activity could be a feasible strategy to limit the deleterious effects of the outbreak.

The systemic exercise-released chemokine lymphotactin/XCL1 modulates in vitro adult hippocampal precursor cell proliferation and neuronal differentiation

Physical exercise has well-established anti-inflammatory effects, with neuro-immunological crosstalk being proposed as a mechanism underlying the beneficial effects of exercise on brain health. Here, we used physical exercise, a strong positive modulator of adult hippocampal neurogenesis, as a model to identify immune molecules that are secreted into the blood stream, which could potentially mediate this process. Proteomic profiling of mouse plasma showed that levels of the chemokine lymphotactin (XCL1) were elevated after four days of running. We found that XCL1 treatment of primary cells isolated from both the dentate gyrus and the subventricular zone of the adult mice led to an increase in the number of neurospheres and neuronal differentiation in neurospheres derived from the dentate gyrus. In contrast, primary dentate gyrus cells isolated from XCL1 knockout mice formed fewer neurospheres and exhibited a reduced neuronal differentiation potential. XCL1 supplementation in a dentate gyrus-derived neural precursor cell line promoted neuronal differentiation and resulted in lower cell motility and a reduced number of cells in the S phase of the cell cycle. This work suggests an additional function of the chemokine XCL1 in the brain and underpins the complexity of neuro-immune interactions that contribute to the regulation of adult hippocampal neurogenesis.

Effects of exercise on inflammation in patients receiving chemotherapy: a nationwide NCORP randomized clinical trial

Purpose.

A growing body of research suggests that inflammation plays a role in many chemotherapy-related toxicities such as fatigue, anxiety, and neuropathy. Regular exercise can change levels of individual cytokines (e.g., reducing IL-6, increasing IL-10); however, it is not known whether exercise during chemotherapy affects relationships between cytokines (i.e., whether cytokine concentrations change collectively vs. independently). This study assessed how 6 weeks of exercise during chemotherapy affected relationships between changes in concentrations of several cytokines.

Methods.

This is a secondary analysis of a randomized trial studying 6 weeks of moderate-intensity walking and resistance exercise during chemotherapy compared to chemotherapy alone. At pre- and post-intervention, patients provided blood to assess serum concentrations of cytokines IL-1β, IL-6, IL-8, IL-10, and IFN-γ, and receptor sTNFR1. We investigated relationships between cytokines using the correlations between changes in cytokine concentrations from pre- to post-intervention.

Results.

We obtained complete data from 293 patients (149 randomized to exercise). Exercise strengthened the correlation between concentration changes of IL-10 and IL-6 (r=0.44 in exercisers vs. 0.11 in controls; p=0.001). We observed the same pattern for IL-10:IL-1β and IL-10:sTNFR1. Exercise also induced an anti-inflammatory cytokine profile, per reductions in pro-inflammatory IFNγ (p=0.044) and perhaps IL-1β (p=0.099, trend-level significance).

Conclusions.

Our hypothesis-generating work suggests that regular exercise during 6 weeks of chemotherapy may cause certain cytokine concentrations to change collectively (not independently). This work enhances our understanding of relationships between cytokines and complements traditional analyses of cytokines in isolation. Future work should test for replication and relationships to patient outcomes.

Exercise, Immunity, and Illness

It is generally accepted that moderate amounts of exercise improve immune system functions and hence reduce the risk of infection whereas athletes engaged in regular prolonged and/or intensive training have a higher than “normal” incidence of minor infections, especially of the upper respiratory tract (URT, e.g., common cold and influenza). This is likely related to regular acute (and possibly chronic) periods of exercise-induced changes in immune function. URT infections can compromise performance directly if suffered shortly before or during competition or indirectly if suffered at other times via effects on training and/or physiological adaptations. This chapter covers the effects of exercise (acute and chronic), both positive and negative, on immune function and consequent infection risk, and considers the current state-of-the-art for monitoring and assessing this in athletes.

Moderate Exercise Enhances the Production of Interferon-γ and Interleukin-12 in Peripheral Blood Mononuclear Cells

The purpose of this study was to explore the effect of two months moderate exercise on levels of IFN-γ, IL-12, IL-6 and IL-4 in serum and supernatants of in vitro mitogen-activated (PHA for 48 h) whole blood (WB) and peripheral blood mononuclear cells (PBMCs). Sixteen healthy males participated in running program (30 min/day, 5 days/week). Blood samples were collected in three stages; 24 h before to start exercise, 48 h and two months after the last session of the exercise. The samples were analyzed for the cytokines by ELISA. The levels of IFN-γ and IL-12 were increased significantly in activated PBMCs culture after exercise and were back to normal level after two months rest. A significant elevation of IFN-γ/IL-4 ratio was observed in activated PBMCs culture by acting possibly on IFN-γ. The results suggest that short moderate intensity exercise enhances Th1 immune inflammatory and anti-allergic conditions in response to mitogen.

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.

Effect of acute exercise and hypoxia on markers of systemic and mucosal immunity

Purpose

To determine how immune markers are affected by acute hypoxic exercise at the same relative intensity.

Methods

Twelve endurance-trained males (age: 28 ± 4 years, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max: 63.7 ± 5.3 mL/kg/min) cycled for 75 min at 70 % of altitude-specific \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max, once in normoxia (N) and once in hypobaric hypoxia equivalent to 2000 m above sea-level (H). Blood and saliva samples were collected pre-, post- and 2 h post-exercise.

Results

Participants cycled at 10.5 % lower power output in H vs. N, with no significant differences in heart rate (P = 0.10) or rating of perceived exertion (P = 0.21). Post-exercise plasma cortisol was higher in H vs. N [683 (95 % CI 576–810) nmol/l vs. 549 (469–643) nmol/l, P = 0.017]. The exercise-induced decrease in CD4:CD8 ratio was greater in H vs. N (−0.5 ± 0.2 vs. −0.3 ± 0.2, P = 0.019). There were no significant between-trial differences for adrenocorticotropic hormone, plasma cytokines, antigen-stimulated cytokine production, salivary immunoglobulin-A or lactoferrin. However, there was a main trial effect for concentration [F(11) = 5.99, P < 0.032] and secretion [F(11) = 5.01, P < 0.047] of salivary lysozyme, with this being higher in N at every time-point.

Conclusion

Whether the observed differences between H and N are of sufficient magnitude to clinically impair host defence is questionable, particularly as they are transient in nature and since other immune markers are unaffected. As such, acute hypoxic exercise likely does not pose a meaningful additional threat to immune function compared to exercise at sea level, provided that absolute workload is reduced in hypoxia so that relative exercise intensity is the same.

Nutritional and Physical Activity Interventions to Improve Immunity

Physical activity and nutrition are important in a healthy lifestyle with potential benefits to immunity often overlooked. Infection of the upper respiratory tract, and the associated symptoms, are the most frequent presentations to general practitioners and may have significant economic and social impact. In this review, we consider the role of physical activity and nutrition in improving immunity. Evidence suggests that regular moderate activity is particularly beneficial for immune enhancement and reducing the risk of infection. We also discuss some nutritional strategies. Unfortunately, the evidence for many is weak. Avoiding nutritional deficiencies seems the most pragmatic recommendation. This can be achieved with a balanced diet. Including a variety of fruits and vegetables may help ensure adequate intake of essential nutrients with little risk of excess intake of any single nutrient. Supplementation with individual nutrients is generally not recommended. Multinutrients may be beneficial for those with a preexisting deficiency but not if normal dietary intake is sufficient. Further benefit may be gained from some supplements including probiotics, bovine colostrum, and some plant-derived products (Echinacea, black elderberry, and some polyphenols) but only in specific situations/contexts. Individuals should consider their personal needs, use caution, and avoid the indiscriminate use of supplements.

Carbohydrate and glutamine supplementation modulates the Th1/Th2 balance after exercise performed at a simulated altitude of 4500 m

OBJECTIVE

The aim of this study was to evaluate the effect of carbohydrate or glutamine supplementation, or a combination of the two, on the immune system and inflammatory parameters after exercise in simulated hypoxic conditions at 4500 m.

METHODS

Nine men underwent three sessions of exercise at 70% VO2peak until exhaustion as follows: 1) hypoxia with a placebo; 2) hypoxia with 8% maltodextrin (200 mL/20 min) during exercise and for 2 h after; and 3) hypoxia after 6 d of glutamine supplementation (20 g/d) and supplementation with 8% maltodextrin (200 mL/20 min) during exercise and for 2 h after. All procedures were randomized and double blind. Blood was collected at rest, immediately before exercise, after the completion of exercise, and 2 h after recovery. Glutamine, cortisol, cytokines, glucose, heat shock protein-70, and erythropoietin were measured in serum, and the cytokine production from lymphocytes was measured.

RESULTS

Erythropoietin and interleukin (IL)-6 increased after exercise in the hypoxia group compared with baseline. IL-6 was higher in the hypoxia group than pre-exercise after exercise and after 2 h recovery. Cortisol did not change, whereas glucose was elevated post-exercise in the three groups compared with baseline and pre-exercise. Glutamine increased in the hypoxia + carbohydrate + glutamine group after exercise compared with baseline. Heat shock protein-70 increased post-exercise compared with baseline and pre-exercise and after recovery compared with pre-exercise, in the hypoxia + carbohydrate group. No difference was observed in IL-2 and IL-6 production from lymphocytes. IL-4 was reduced in the supplemented groups.

CONCLUSION

Carbohydrate or glutamine supplementation shifts the T helper (Th)1/Th2 balance toward Th1 responses after exercise at a simulated altitude of 4500 m. The nutritional strategies increased in IL-6, suggesting an important anti-inflammatory effect.

Influence of Hydration Status on Changes in Plasma Cortisol, Leukocytes, and Antigen-Stimulated Cytokine Production by Whole Blood Culture following Prolonged Exercise

Elevated antigen-stimulated anti-inflammatory cytokine production appears to be a risk factor for upper respiratory tract illness in athletes. The purpose of this study was to determine the effects of prolonged exercise and hydration on antigen-stimulated cytokine production. Twelve healthy males cycled for 120 min at 60% V˙O2max⁡ on two occasions, either euhydrated or moderately hypohydrated (induced by fluid restriction for 24 h). Blood samples were collected before and after exercise and following 2 h recovery for determination of cell counts, plasma cortisol, and in vitro antigen-stimulated cytokine production by whole blood culture. Fluid restriction resulted in mean body mass loss of 1.3% and 3.9% before and after exercise, respectively. Exercise elicited a significant leukocytosis and elevated plasma cortisol, with no differences between trials. IL-6 production was significantly reduced 2 h postexercise (P < 0.05), while IL-10 production was elevated postexercise (P < 0.05). IFN-γ and IL-2 production tended to decrease postexercise. No significant effect of hydration status was observed for the measured variables. Prolonged exercise appears to result in augmented anti-inflammatory cytokine release in response to antigen challenge, possibly coupled with acute suppression of proinflammatory cytokine production, corresponding with studies using mitogen or endotoxin as stimulant. Moderate hypohydration does not appear to influence these changes.

A half-marathon and a marathon run induce oxidative DNA damage, reduce antioxidant capacity to protect DNA against damage and modify immune function in hobby runners

This study investigated whether a 21.1 km (half-marathon) or a 42.195 km (marathon) run modulates DNA damage, antioxidant capacity in lymphocytes and plasma, and the immune system in healthy hobby runners. Ten and 12 volunteers who completed the Baden-Marathon race in Karlsruhe with a running distance of 21.1 km and 41.195 km, respectively, were assessed 10 days before and immediately after the finish. There was no increase in the levels of endogenous DNA strand breaks immediately after half-marathon or marathon races. A statistically significant increase in the levels of oxidative DNA damage in lymphocytes was found using endonuclease III but not formamidopyrimidine glycolase (Fpg). The resistance of DNA to oxidative damage induced by hydrogen peroxide in isolated lymphocytes was significantly decreased after both races. The levels of plasma antioxidants such as alpha-tocopherol, beta-carotene and lycopene were close to, or higher than, those considered optimal for reducing the risk of cardiovascular diseases and there were no significant changes after the races in antioxidant capacity of LDL (lag-time test) or plasma in ORAC, TEAC or paraoxonase assays. The number and percentage of granulocytes and monocytes able to generate oxidative burst were significantly increased after both races, but the lytic activity of NK cells was significantly increased at the end of the half-marathon; no effect was observed in the marathon runners. Thus, oxidative DNA damage in lymphocytes, decreased the antioxidant capacity to protect lymphocytes against DNA strand breaks and increased the formation of reactive species by phagocytes in well-nourished hobby runners indicating moderate oxidative damage during such high-intensity exercise.

Brief Exercise Increases Peripheral Blood NK Cell Counts without Immediate Functional Changes, but Impairs their Responses to ex vivo Stimulation

Physical as well as psychological stress increases the number of circulating peripheral blood NK cells. Whereas some studies found a positive correlation between exercise and NK cell counts and cytotoxic activity, others showed that, for example, heavy training leads to a decrease in per cell NK cytotoxicity. Thus, the impact of exercise on NK cell function and eventually on altered immunocompetence remains to be elucidated. Here, we investigated whether a single bout of brief exercise, consisting in running up and down 150 stair-steps, affects the number and function of circulating NK cells. NK cells, obtained from 29 healthy donors, before and immediately after brief exercise, were assessed for numbers, phenotype, IFNγ production, degranulation, cytotoxicity, and in vitro response to stimulation with IL-2, IL-2/IL-12, or TLR2 agonists. Running resulted in a sixfold increase in the number of CD3⁻/CD56⁺ NK cells, but decreased the frequency of CD56^bright NK cells about twofold. Brief exercise did not significantly interfere with baseline IFNγ secretion or NK cell cytotoxicity. In vitro stimulation with IL-2 and TLR2 agonists (lipoteichoic acid, and synthetic triacylated lipopeptide Pam3CSK4) enhanced IFNγ-secretion, degranulation, and cytotoxicity mediated by NK cells isolated pre-exercise, but had less effect on NK cells isolated following exercise. There were no differences in response to combined IL-2/IL-12 stimulation. In conclusion, having no obvious impact on baseline NK functions, brief exercise might be used as a simple method to significantly increase the number of CD56^dim NK cell available for in vitro experiments. Nevertheless, the observed impaired responses to stimulation suggest an alteration of NK cell-mediated immunity by brief exercise which is at least in part explained by a concomitant decrease of the circulating CD56^bright NK cell fraction.

Fish oil supplementation augments post-exercise immune function in young males

PURPOSE

Fish oils and related fatty acid components have anti-inflammatory properties, with beneficial effects against various disorders such as cardiovascular disease. A single bout of exercise can alter immune function. However, the effects of fish oil on immune function after a single bout of exercise are currently unknown. This study investigated the effect of supplementation with fish oil on the immune response to an acute bout of endurance exercise.

METHODS

Sixteen male subjects underwent a six week double blind randomised placebo controlled supplementation trial involving two groups (fish oil or placebo oil, 3g/day). They attended for two visits, the first involving a maximal exercise test and the second involving a 1-h bout of endurance exercise on a cycle ergometer at 70% (V)O(2peak). Blood samples were taken pre-supplementation, pre-exercise (post-supplementation), immediately, 1 and 3h post-exercise. Samples were analysed for plasma IL-6, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and cortisol; peripheral blood mononuclear cell (PBMC) IL-2, IL-4 and IFN-γ production; neutrophil phagocytosis/oxidative burst; and natural killer (NK) cell cytotoxic activity.

RESULTS

Post-supplementation EPA concentration was increased (P=0.0127) in the fish oil group. At 3h post-exercise PBMC IL-2 (P=0.0067) and NK cell activity (P=0.0163) was greater in the fish oil compared with the control group. However, PBMC IL-4 and IFN-γ productions, plasma IL-6 and cortisol concentrations, as well as neutrophil activity were unaffected by fish oil supplementation.

CONCLUSION

The current study demonstrates that fish oil supplementation reduces increases PBMC IL-2 production and NK cell cytotoxic activity in the recovery period after exercise.

Exercise-induced increases in inflammatory cytokines in muscle and blood of horses

REASONS FOR PERFORMING STUDY

Studies have demonstrated increases in mRNA expression for inflammatory cytokines following exercise in horses and have suggested those markers of inflammation may play a role in delayed onset muscle soreness. However, measurement of mRNA expression in white blood cells is an indirect method. No studies to date have documented the cytokine response to exercise directly in muscle in horses.

HYPOTHESIS

This study tested the hypothesis that exercise increases cytokine markers of inflammation in blood and muscle.

METHODS

Blood and muscle biopsies were obtained from 4 healthy, unfit Standardbred mares (∼ 500 kg). The randomised crossover experiment was performed with the investigators performing the analysis blind to the treatment. Each horse underwent either incremental exercise test (GXT) or standing parallel control with the trials performed one month apart. During the GXT horses ran on a treadmill (1 m/s increases each min until fatigue, 6% grade). Blood and muscle biopsies were obtained 30 min before exercise, immediately after exercise and at 0.5, 1, 2, 6 and 24 h post GXT or at matched time points during the parallel control trials. Samples were analysed using real time-PCR for measurement of mRNA expression of interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-1 (IL-1). Data were analysed using t tests with the null hypothesis rejected when P < 0.10.

RESULTS

There were no changes (P > 0.10) in IL-1, IL-6, IFN-gamma or TNF-alpha during control. Exercise induced significant increases in IFN-gamma, IL1 and TNF-alpha in blood and significant increases in IFN-gamma, IL-6 and TNF-alpha in muscle. There were no significant changes in mRNA expression of IL-1 in muscle or IL-6 in blood following the GXT. These cytokine markers of inflammation all returned to preGXT levels by 24 h post GXT.

CONCLUSION

High intensity exercise results in a transient increase in the expression of inflammatory cytokines in muscle and blood.

The interactive effect of exercise and immunosuppressant cyclosporin A on immune function in mice

Cyclosporin A (CsA) is an effective immunosuppressive agent and exerts its actions by interfering with the activation of T cells. There is growing evidence that regular exercise improves immune function. However, the effects of exercise on immune functions in patients taking CsA are unclear. Here, we examine the interactive effects of CsA administration and regular exercise on immune function in mice. Forty-eight BALB/c mice were randomly assigned to one of six groups with eight mice per group: 0-Ex (no CsA/no exercise), 0 + Ex (no CsA + exercise), 10-Ex (10 mg kg(-1) day(-1) CsA/no exercise), 10 + Ex (10 mg kg(-1) day(-1) CsA + exercise), 20-Ex (20 mg kg(-1) day(-1) CsA/no exercise), and 20 + Ex (20 mg kg(-1) day(-1) CsA + exercise). The three exercise groups were trained for 8 weeks, three times a week, at approximately 75% maximum oxygen uptake (VO(2max)). Nitric oxide and interferon-gamma secretions by mitogen-activated macrophages and spleen cells, respectively, were higher in exercise groups than in non-exercise groups receiving the same doses of CsA. The results of this study indicate that regular exercise may enhance Type I helper T cell functions in mice receiving 10 or 20 mg kg(-1) day(-1) CsA. Our results demonstrate that moderate regular exercise modulates the immune function of CsA-treated mice. However, whether this exercise-induced immunomodulatory effect is beneficial or detrimental to CsA-treated patients needs to be clarified.

Effect of orange peel and black tea extracts on markers of performance and cytokine markers of inflammation in horses

This study tested the hypothesis that orange peel (O) and decaffeinated black tea (T) extracts would alter markers of exercise performance as well as exercise-induced mRNA expression for the inflammatory cytokines IL-6, TNF-alpha and IFN-gamma. Nine healthy, unfit Standardbred mares (age: 10±4years, ∼450kg) were assigned to three treatment groups in a randomized crossover design where each horse was administered one of the following; placebo (O; 21 water), black tea extract in water (T; 21) or orange peel extract in water (W; 21), via a nasogastric tube. One hour later the horses completed an incremental graded exercise test (GXT) on a treadmill at a fixed 6% grade with measurements and blood samples obtained at rest, at the end of each 1min step of the GXT and at 2 and 5min post-GXT. An additional set of blood samples for Polymerase Chain Reaction (PCR) measurements of mRNA was obtained before exercise and at 5 and 30min and 1, 2, 4 and 24h post-GXT. The GXTs were conducted between 0700 and 1200h not less than 7days apart. There were no differences (P>0.05) in VO2max, respiratory exchange ratio, run time, velocity at VO2max, core body temperature, haematocrit, creatine kinase (CK), plasma lactate concentrations, HR, right ventricular pressure (RVP) or pulmonary artery pressure (PAP) across treatments. A major finding was that orange peel extract significantly reduced post-exercise VO2 recovery time (W = 112±7, O = 86±6, and T = 120±11s). There was a significant difference in plasma total protein concentration (TP) in the O runs compared with water and T. TNF-alpha mRNA expression was lower in the T runs compared with water and O trials. IFN-gamma mRNA expression levels appeared to be lower in both the T and O extract runs compared with the water trials. The mRNA expression of IL-6 was unaltered across treatment groups. These data suggest that orange peel and black tea extracts may modulate the cytokine responses to intense exercise. Orange peel extract reduced post-exercise recovery time and may potentially enhance the ability of horses to perform subsequent bouts of high-intensity exercise.

Effect of prolonged exercise and carbohydrate ingestion on type 1 and type 2 T lymphocyte distribution and intracellular cytokine production in humans

The present study was undertaken to examine the role of the exercise-induced stress hormone response on the regulation of type 1 and type 2 T lymphocyte intracellular cytokine production. Subjects performed 2.5 h of cycling exercise at 65% maximal O2 uptake while ingesting a 6.4% carbohydrate (CHO) solution, 12.8% CHO solution, or a placebo. Peripheral whole blood samples were stimulated and stained for T lymphocyte surface antigens (CD4 and CD8). Cells were then permeabilized, stained for intracellular cytokines, and analyzed using flow cytometry. Exercise resulted in a decrease (P < 0.05) in the number and percentage of IFN-gamma positive CD4+ and CD8+ T lymphocytes. These stimulated cells produced less IFN-gamma immediately postexercise (P < 0.05) and 2-h postexercise (P < 0.05) compared with preexercise. However, CHO ingestion, which attenuated the exercise-induced stress hormone response compared with placebo (P < 0.05), prevented both the decrease in the number and percentage of IFN-gamma-positive CD4+ and CD8+ T lymphocytes and the suppression of IFN-gamma production from stimulated CD4+ and CD8+ T lymphocytes. There was no effect of exercise on the number of, or cytokine production from, IL-4-positive CD4+ or CD8+ T lymphocytes. These data provide support for the role of exercise-induced elevations in stress hormones in the regulation of type 1 T lymphocyte cytokine production and distribution.

Decreased interleukin-1 receptor antagonist response following moderate exercise in patients with colorectal carcinoma after primary treatment

Clinical and experimental studies have shown that a moderately increased physical activity level may have beneficial effects in terms of exercise conditioning, resistance to infection and decreased relative risk of cancer. Modulation of the innate and adaptive components of the immune system with a shift of cytokines and their antagonists to a more pro- and less anti-inflammatory response was found to be a prominent feature in non-tumor patients and healthy volunteers. As quantitative data concerning the cytokine/antagonist response following exercise are not available for tumor patients, we compared the effects of a post-operative rehabilitation program with moderate exercise (ME) intensity (0.55-0.65 x maximal aerobic power) with a program with low exercise (LE) intensity (0.30-0.40 x maximal aerobic power) in patients with curatively treated colorectal carcinoma (UICC II and III) measuring pro- (IL-1beta, IL-6, tumour necrosis factor (TNF)) and anti-inflammatory cytokines (IL-1 receptor antagonist, sTNF receptors I and II). Twenty-three patients participated in this prospective trial, N = 13 in the ME group, N = 10 in the LE group. Exercise was performed daily 30-40 min for 2 weeks. Basal (circulating) and LPS-stimulated (phasic) cytokine and antagonist response was determined before exercise and after 1 and 2 weeks using appropriate ELISA tests. The LPS-stimulated interleukin-1 receptor antagonist (IL-1ra) response in the ME group gradually decreased from 31,532.6 (160.0-70,028.0) to 18,033.0 pg/ml (5040.0-52,570.0) after one and to 22,892.0 pg/ml (6376.0-34,726.0) after 2 weeks (P < 0.05) with a concomitant decrease of the corresponding IL-1ra/IL-6 and IL-1ra/IL-1beta ratio: 2.51-1.41 and 4.1-3.1, respectively. In contrast, in the LE group LPS-stimulated cytokines and antagonists did not significantly change during exercise. Circulating cytokines and antagonists remained unchanged in both groups. In providing quantitative data in patients with curatively-treated colorectal cancer, we demonstrated that a short-term rehabilitation program with moderate exercise leads to a decreased LPS-induced antagonist response with a shift to a more pro-inflammatory state (decreased antagonist/cytokine ratio). Whether this change of the phasic immune response to moderate exercise may be clinically beneficial (decreased rates of infection, relapses and/or second tumours) is possible, but has to be investigated in long-term studies.

Does training affect mRNA transciption for cytokine production in circulating leucocytes?

Physical exertion is a stimulus for the upregulation of cytokine production including IL-1beta, IL-1ra, IL-2, IL-4, IL-6, IL-10 and TNF-alpha in horses. To investigate that hypothesis, we initiated training of 5 stall-rested Thoroughbreds. Blood samples were drawn before and weekly during training. The relative transcription of mRNA within the leucocytes was measured using real time TaqMan quantitative PCR. The training protocol was walking (3 min), trotting (3 min) and cantering/galloping (6 min) increasing in intensity weekly (6 to 12 m/s) and culminating in an intense exercise period. Comparisons of mRNA concentrations were made using a repeated measures ANOVA on ranks and a Student-Newman-Keuls pair-wise multiple comparison (P<0.05). The training programme or intense exercise bout did not affect IL-2, IL-4, IL-6 and IL-10. IL1-beta and TNF-alpha transcription increased on Day 23. TNF-alpha peaked on Day 23 and IL1-beta on Day 30. Neither demonstrated a response to intense exercise. IL-1ra decreased significantly on Day 9; rose significantly from Day 9 to Days 16 and 23; remained significantly elevated through Days 30 and 37 over Day 9, and rose very slightly after intense exercise on Day 56. Alterations in leukocyte cytokine responses may influence susceptibility to infectious disease, metabolic responses to exercise or exercised induced syndromes.

Exercise-induced change in type 1 cytokine-producing CD8+ T cells is related to a decrease in memory T cells

In response to exercise, both CD4(+) and CD8(+) T cells are mobilized to the blood, but the levels of these cells decline below preexercise values in the postexercise period. T cells are functionally polarized, depending on the cytokines they produce. Type 1 cells produce, e.g., interferon (INF)-gamma, whereas type 2 produce, e.g., interleukin (IL)-4. It was recently demonstrated that exercise induces a decrease in the percentage of type 1 T cells. The present study further investigated the mechanisms underlying the exercise-induced shift in the balance between type 1 and type 2 cytokine-producing cells. Seven healthy men performed 1.5 h of treadmill running with blood samples drawn before exercise, at the end of exercise, and 2 h after exercise. Intracellular expression of IFN-gamma, IL-2, and IL-4 was detected in CD4(+) and CD8(+) T cells after stimulation with phorbol 12-myristate 13-acetate and ionomycin. Intracellular expression of IFN-gamma within CD8(+) cells was decreased in the postexercise period compared with values obtained immediately after exercise, whereas the expression of IL-2 and IL-4 did not change within the CD4(+) and CD8(+) cell populations. The decrease in IFN-gamma-producing CD8(+) T cells postexercise was negatively correlated with a decrease in percentage of memory T cells within the CD8(+) cells (r = -0.94; P < or = 0.002). In conclusion, this study demonstrates that the exercise-induced change in type 1 cytokine-producing T cells is related to a decline in memory cells.

Immunomodulatory action of chronic exercise on macrophage and lymphocyte cytokine production in mice

This study was designed to evaluate the effects of 8-week voluntary running exercise on cytokine production of macrophages and lymphocytes. Seven-week-old-male BALB/c inbred mice were divided into two groups: a group given voluntary exercise (exercise group, n=32), and the other, a non-exercise group (control group, n=32). Exercise consisted of spontaneous running in wheels for 3 days per week over 8 weeks. The levels of nitric oxide (NO2-) and interleukin (IL)-1 beta production by lipopolysaccharide (LPS)-stimulated peritoneal macrophages from the exercise group was significantly higher than that in the control group (P < 0.05-P < 0.01). In the exercise group, stimulation indices by concanavalin A (Con A) was significantly higher than they were in the control group (P < 0.05-P < 0.001). When compared with the control group, the exercise group showed a significant (P < 0.05) increase in the splenic lymphocyte production of IL-2 stimulated by Con A (449.5 +/- 28.2 and 853.7 +/- 116.0 pg 4 x 10(5) cells(-1) 48 h(-1) for the control group and the exercise group, respectively). IL-4 production of splenocytes stimulated by Con A in the exercise group (37.6 +/- 5.1 pg 4 x 10(5) cells(-1) 48 h(-1)) was higher than that in the control group (30.9 +/- 3.9 pg 4 x 10(5) cells(-1) 48 h(-1)); however, the difference was not statistically significant. These results suggest that 8-week voluntary running exercise effectively enhanced macrophage and lymphocyte functions in mice.

Effect of adrenergic blockade on lymphocyte cytokine production at rest and during exercise

To examine the effect of exercise and adrenergic blockade on lymphocyte cytokine production, six men ingested either a placebo (control) or an alpha- (prazosin hydrochloride) and beta-adrenoceptor antagonist (timolol malate) capsule (blockade, or BLK) 2 h before performing 19 +/- 1 min of supine bicycle exercise at 78 +/- 3% peak pulmonary uptake. Blood was collected before and after exercise, stimulated with phorbol 12-myristate 13-acetate and ionomycin, and surface stained for T (CD3(+)) and natural killer [NK (CD3(-)CD56(+))] lymphocyte surface antigens. Cells were permeabilized, stained for the intracellular cytokines interleukin (IL)-2 and interferon (IFN)-gamma, and analyzed using flow cytometry. BLK had no effect on the resting concentration of stimulated cytokine-positive T and NK lymphocytes or the amount of cytokine they were producing. Exercise resulted in an increase (P < 0.05) in the concentration of stimulated T and NK lymphocytes producing cytokines in the circulation, but these cells produced less (P < 0.05) cytokine post- compared with preexercise. BLK attenuated (P < 0.05) the elevation in the concentration of lymphocytes producing cytokines during exercise; however, BLK did not affect the amount of IL-2 and IFN-gamma produced. These results suggest that adrenergic stimulation contributes to the exercise-induced increase in the concentration of lymphocytes in the circulation; however, it does not appear to be responsible for the exercise-induced suppression in cytokine production.

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.

Special feature for the Olympics: effects of exercise on the immune system: exercise effects on systemic immunity

Heavy exertion has acute and chronic influences on systemic immunity. In the resting state, the immune systems of athletes and non-athletes are more similar than disparate with the exception of NK cell activity, which tends to be elevated in athletes. Many components of the immune system exhibit adverse change after prolonged, heavy exertion. These immune changes occur in several compartments of the immune system and body (e.g. the skin, upper respiratory tract mucosal tissue, lung, blood and muscle). Although still open to interpretation, most exercise immunologists believe that during this 'open window' of impaired immunity (which may last between 3 and 72 h, depending on the immune measure) viruses and bacteria may gain a foothold, increasing the risk of subclinical and clinical infection. The infection risk may be amplified when other factors related to immune function are present, including exposure to novel pathogens during travel, lack of sleep, severe mental stress, malnutrition or weight loss.