Serum from exercising humans suppresses t-cell cytokine production

Host characteristics associated with serologic inflammatory biomarkers in women

BACKGROUND

There is growing evidence that exposure to low-grade inflammation may be associated with adverse health outcomes.

METHODS

We conducted a cross-sectional study within the California Teachers Study prospective cohort, among female participants who had completed a questionnaire that asked about their health behaviors (e.g., diabetes, physical activity, body mass index, medication use) and who had donated blood within a year of their questionnaire. 822 women with stored serum were evaluated for 16 immune biomarkers. In addition, four immune pathways were constructed: Th1, pro-inflammatory/macrophage activation, B-cell activation, and T-cell activation. Odds ratios (ORs) and 95% confidence intervals (CI) for the association between host characteristics and immune biomarkers were assessed using logistic regression models.

RESULT

Compared to women of a normal BMI, obese women (>30 kg/m2) were positively associated with sTNFR2, CD27, IL6, CXCL13, sIL-2Rα, and IL6Ra levels above the median, with odds ratios ranging from 1.5 to 6.0. The pro-inflammatory/macrophage activation pathway was positively associated with diabetes (OR = 2.12, 95% CI = 1.14-3.95), fueled by individual associations between diabetes and sTNF-R2, TNFα and sCD27. Physical activity was inversely associated with sTNF-R2, TNFα, CXCL13, IL6, IL10, and IFN-γ levels, particularly for the highest category of activity (5.88+ hours/week) (ORs = 0.32-0.69). In pathway-based analyses, the Th1 pathway which includes decreased levels of IL4 and IL10 was positively associated with elevated physical activity (OR = 1.5). In contrast, the pro-inflammatory, B- and T-cell activation pathways were positively associated with higher BMI (OR ranging from 1.6 to 3) and inversely associated with increasing levels of physical activity.

CONCLUSIONS

Several host characteristics were associated with circulating levels of immune biomarkers, including markers of inflammation. Further understanding of associations between immune marker profiles with human disease are warranted.

The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

Exercise training and de-training effects on serum leptin and TNF-α in high fat induced diabetic rats

BACKGROUND

Adipocytokines, which are secreted by the adipose tissue, contribute to the pathogenesis of obesity-related complications. To evaluate this assumption, we investigated the effects of aerobic exercise training (AET), resistance exercise training (RET), and 4 weeks of de-training on serum leptin and TNF-α levels in diabetic rats.

METHOD

36 Wistar rats were divided into normal diet (ND) (control, RET, AET) and high-fat diet (HFD) + STZ (control, RET, AET) groups. Serum insulin, leptin, and TNF-α levels were assessed by commercial ELISA kits. Also fasting blood glucose (FBG), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) levels were measured by the colorimetric kits.

RESULTS

Diabetes induction increased body weight (BW) and FBG, and decreased insulin compared to the ND rats' groups (p < 0.001). 12-weeks of AET and RET programs in the trained diabetic rats led to a decrease in TG, LDL-C, leptin, TNF-α, and FBG, and an increase in insulin compared to the HFD + STZ-C group (p < 0.001). Besides, there was no difference between AET and RET in improving the variables studied (p > 0.05). Also, de-training led to increased BW, TG, leptin, and TNF-α compared to the end of the exercise training (p < 0.05). The correlation between the variables studied was established at different stages of the study (p < 0.05), and only BW was not correlated with insulin during exercise training and de-training (p > 0.05).

CONCLUSION

These findings indicate that both AET and RET are useful in reducing levels of serum adipocytokines (TNF-α, leptin) in diabetic and non-diabetic rats. At the same time, 4 weeks of de-training was sufficient to lose the metabolic adaptations.

Immunoregulation induced by autologous serum collected after acute exercise in obese men: a randomized cross-over trial

In this study, we evaluated the effects of autologous serum collected after two types of exercise on the in vitro inflammatory profile and T cell phenotype of resting peripheral blood mononuclear cells (PBMCs) in obese men. Serum samples and PBMCs were obtained from eight obese men who performed two exercise bouts—high intensity interval exercise (HIIE) and exhaustive exercise session to voluntary fatigue—in a randomized cross-over trial. Pre-exercise PBMCs were incubated with 50% autologous serum (collected before and after each exercise bout) for 4 h. In vitro experiments revealed that post-HIIE serum reduced the histone H4 acetylation status and NF-κB content of PBMCs and suppressed the production of both TNF-α and IL-6 by PBMCs, while increasing IL-10 production. Post-exhaustive exercise serum induced histone H4 hyperacetylation and mitochondrial depolarization in lymphocytes and increased TNF-α production. In vitro post-HIIE serum incubation resulted in an increase in the frequencies of CD4 + CTLA-4 + and CD4 + CD25+ T cells expressing CD39 and CD73. Post-exhaustive exercise serum decreased the frequency of CD4 + CD25 + CD73+ T cells but increased CD4 + CD25-CD39 + T cell frequency. Both post-exercise serums increased the proportions of CD4 + PD-1 + and CD8 + PD-1+ T cells. Blood serum factors released during exercise altered the immune response and T cell phenotype. The type of exercise impacted the immunomodulatory activity of the post-exercise serum on PBMCs.

The Effect of Exercise and Psychological Stress on Anti- and Proinflammatory Cytokines

BACKGROUND/AIMS

Research evidence regarding immune system responses and adaptations to psychological or physical stresses is controversial. This study aimed to investigate the effect of 8-week psychological stress and exercise activity (chronic adaptation) and the acute response of possibly adapted rats to psychological stress and exercise considering IFN-γ, IL-4, and IL-4/IFN-γ.

METHODS

Thirty-two rats were divided into 4 groups of 8 animals including control, exercise, psychological stress, and combination of exercise with psychological stress. IL-4 and IFN-γ cytokines were measured pre-experiment (preEX), immediately postexercise (IpostEX), and 72-h postexperiment protocol (72hpostEX).

RESULTS

There were no significant differences between the study groups regarding IFN-γ, IL-4, and IL-4/IFN-γ in preEX (p > 0.05), IpostEX (p > 0.05), and 72hpostEX (p > 0.05). However, IL-4 increased significantly in IpostEX compared with preEX in exercise (p = 0.012) and combination of exercise with psychological stress (p = 0.03) groups.

CONCLUSIONS

Exercise and combination of exercise and psychological stress induce similar acute response to IL-4 in chronic trained and stressed rats. Also, exercise may induce an acute synergistic effect with psychological stress on IL-4.

Autologous serum collected 1 h post-exercise enhances natural killer cell cytotoxicity

Natural Killer cells are cytotoxic lymphocytes that recognize and eliminate tumor cells. Exercise enhances NK cell cytotoxic activity (NKCA), yet the underlying mechanisms are not fully understood. Exercise-induced shifts in NK-cell subsets has been proposed as one mechanism. Alternatively, exercise alters stress hormone and cytokine levels, which are also known to affect NKCA.

AIM

Determine the role(s) of exercise-induced shifts in the proportions of NK-cell subsets found in the blood, and changes in serum IL-2, IL-6, IL-12, IFN-γ, TNF-α and cortisol, on exercise-induced changes in NKCA.

METHODS

Twelve adults cycled 30 min at 115% of their lactate threshold power. Peripheral blood mononuclear cells (PBMCs) and serum were isolated from blood collected pre-, post-, and 1 h post-exercise. To investigate the effect of shifts in NK-cell subsets, pre-, post- and 1 h post-exercise NK cells were incubated with target cells (K562 and U266) in the presence of autologous pre-exercise serum. The effects of hormones and cytokines released during exercise were determined by incubating pre-exercise PBMCs with tumor target cells (K562 and U266) in the presence of pre-, post-, and 1 h post-exercise serum. NKCA and phenotypes were assessed by flow cytometry.

RESULTS

Although exercise mobilized high-differentiated NK cell subsets (NKG2A-/KIR+), NKCA per cell was not altered post-exercise in the presence of pre-exercise serum. Conversely, 1 h post-exercise serum significantly increased the cytotoxicity of pre-exercise NK cells against HLA-expressing target cells (U266). This increase associated with lower levels of cortisol, and occurred when serum contained higher levels of IFN-γ.

CONCLUSIONS

Exercise-induced shifts in NK-cell subsets did not fully explain changes in NKCA. Rather, factors present in serum during exercise recovery enhanced NKCA against target cells. Our results suggest lower cortisol and higher IFN-γ levels may explain exercise-induced changes in NKCA.

Acute bouts of exercise induce a suppressive effect on lymphocyte proliferation in human subjects: A meta-analysis

OBJECTIVE

Lymphocyte proliferative responses are commonly used to assess immune function in clinical settings, yet it is unclear how proliferative capacity is altered by exercise. This analysis aims to quantitatively assess the proliferative response of lymphocytes following an acute bout of exercise.

METHODS

Electronic databases were searched for articles containing the keywords "exercise" OR "acute" OR "aerobic" OR "resistance training" OR "immune function" AND "proliferation" AND "lymphocyte." Initial results yielded 517 articles of which 117 were reviewed in full. Twenty-four articles met the inclusion criteria. Calculated standardized mean difference (SMD) and corresponding standard errors (SE) were integrated using random-effect models.

RESULTS

Analyses uncovered evidence for suppression of proliferative capacity following acute exercise in general (SMD=-0.18, 95% CI: -0.21, -0.16) with long duration, high intensity exercise exhibiting a moderate suppressive effect (SMD=-0.55, 95% CI: -0.86, -0.24). Discordant proliferative responses for long duration, high intensity exercise in competitive versus non-competitive settings were identified with enhanced proliferation (SMD=0.46, 95% CI: 0.03, 0.89) observed following competitive events and a large suppressive effect detected for similar activities outside of a competitive environment (SMD: -1.28, 95% CI: -1.61, -0.96) (p=0.02).

CONCLUSION

Evidence suggests lymphocyte proliferation is suppressed following acute bouts of exercise, with exercise lasting longer than one hour having a greater magnitude of effect regardless of exercise intensity. Variations in observed effect sizes across intensity, duration, and competitive environment further highlight our need to acknowledge the impact of study designs in advancing our understanding of exercise immunology.

Leukocytosis, muscle damage and increased lymphocyte proliferative response after an adventure sprint race

The effect of an adventure sprint race (ASR) on T-cell proliferation, leukocyte count and muscle damage was evaluated. Seven young male runners completed an ASR in the region of Serra do Espinhaço, Brazil. The race induced a strong leukocytosis (6.22±2.04×10³ cells/mm³ before vs 14.81±3.53×10³ cells/mm³ after the race), marked by a significant increase of neutrophils and monocytes (P<0.05), but not total lymphocytes, CD3⁺CD4⁺ or CD3⁺CD8⁺ cells. However, the T-cell proliferative response to mitogenic stimulation was increased (P=0.025) after the race, which contradicted our hypothesis that ASR, as a high-demand competition, would inhibit T-cell proliferation. A positive correlation (P=0.03, r=0.79) was observed between the proliferative response of lymphocytes after the race and the time to complete the race, suggesting that the proliferative response was dependent on exercise intensity. Muscle damage was evident after the race by increased serum levels of aspartate amino transferase (24.99±8.30 vs 50.61±15.76 U/L, P=0.003). The results suggest that humoral factors and substances released by damaged muscle may be responsible for lymphocyte activation, which may be involved in muscle recovery and repair.

Functional genomics in the study of mind-body therapies

BACKGROUND

Mind-body therapies (MBTs) are used throughout the world in treatment, disease prevention, and health promotion. However, the mechanisms by which MBTs exert their positive effects are not well understood. Investigations into MBTs using functional genomics have revolutionized the understanding of MBT mechanisms and their effects on human physiology.

METHODS

We searched the literature for the effects of MBTs on functional genomics determinants using MEDLINE, supplemented by a manual search of additional journals and a reference list review.

RESULTS

We reviewed 15 trials that measured global or targeted transcriptomic, epigenomic, or proteomic changes in peripheral blood. Sample sizes ranged from small pilot studies (n=2) to large trials (n=500). While the reliability of individual genes from trial to trial was often inconsistent, genes related to inflammatory response, particularly those involved in the nuclear factor-kappa B (NF-κB) pathway, were consistently downregulated across most studies.

CONCLUSION

In general, existing trials focusing on gene expression changes brought about by MBTs have revealed intriguing connections to the immune system through the NF-κB cascade, to telomere maintenance, and to apoptotic regulation. However, these findings are limited to a small number of trials and relatively small sample sizes. More rigorous randomized controlled trials of healthy subjects and specific disease states are warranted. Future research should investigate functional genomics areas both upstream and downstream of MBT-related gene expression changes-from epigenomics to proteomics and metabolomics.

Changes in transcriptional output of human peripheral blood mononuclear cells following resistance exercise

Various types of exercise alter the population of circulating peripheral blood mononuclear cells (PBMCs) and change their transcriptional output. This work examines changes in PBMC populations and transcription in response to resistance exercise training (RET), and identify key transcriptional changes in PBMCs that may play a role in altering peripheral tissues in response to RET. Ten resistance-trained men (20-24 years), performed an acute bout of RET for ~30 min following a 12 h fast. Venous blood was sampled at rest, immediately following exercise, and at 2 h post-exercise and analyzed for total and differential leukocytes and global gene expression using Affymetrix Genechips. Results showed elevated leukocytes, monocytes, lymphocytes, and lactate values immediately post-exercise (P < 0.05) over baseline. At 2 h post-exercise, leukocytes, and granulocytes remained elevated (P < 0.05), whereas lymphocytes were lower than (P < 0.05) baseline values. Initial microarray results showed the greatest transcriptional changes in pathways related to immune response, inflammation, and cellular communication. The change in PBMC population (2 h time point) correlated with a dramatic decrease in the expression of CD160, and XCL1, markers of lymphocyte populations. At the 2 h recovery time point upregulation of matrix metalloproteinase 9, orosomucoid 1, dishevelled-associated activator of morphogenesis 2, and arginase 1 suggest an induction in muscle damage and repair during this time frame. These results demonstrate that an acute bout of RET disrupts cellular homeostasis, induces a transient redistribution of certain leukocytes, and results in transcriptional changes in PBMCs translating into systemic changes in response to RET.

Effects of resistance training on the inflammatory response

Resistance training (RT) is associated with reduced risk of low grade inflammation related diseases, such as cardiovascular disease and type 2 diabetes. The majority of the data studying cytokines and exercise comes from endurance exercise. In contrast, evidence establishing a relationship between RT and inflammation is more limited. This review focuses on the cytokine responses both following an acute bout, and after chronic RT. In addition, the effect of RT on low grade systemic inflammation such as individuals at risk for type 2 diabetes is reviewed. Cytokines are secreted proteins that influence the survival, proliferation, and differentiation of immune cells and other organ systems. Cytokines function as intracellular signals and almost all cells in the body either secrete them or have cytokine receptors. Thus, understanding cytokine role in a specific physiological situation such as a bout of RT can be exceedingly complex. The overall effect of long term RT appears to ameliorate inflammation, but the specific effects on the inflammatory cytokine, tumor necrosis factor alpha are not clear, requiring further research. Furthermore, it is critical to differentiate between chronically and acute Interleukin-6 levels and its sources. The intensity of the RT and the characteristics of the training protocol may exert singular cytokine responses and as a result different adaptations to exercise. More research is needed in the area of RT in healthy populations, specifically sorting out gender and age RT acute responses. More importantly, studies are needed in obese individuals who are at high risk of developing low grade systemic inflammatory related diseases. Assuring adherence to the RT program is essential to get the benefits after overcoming the first acute RT responses. Hence RT could be an effective way to prevent, and delay low grade systemic inflammatory related diseases.

Mind-Body Medicine and Immune System Outcomes: A Systematic Review

This study is a systematic review of mind-body interventions that used immune outcomes in order to: 1) characterize mind-body medicine studies that assessed immune outcomes, 2) evaluate the quality of mind-body medicine studies measuring immune system effects, and 3) systematically evaluate the evidence for mind-body interventions effect on immune system outcomes using existing formal tools. 111 studies with 4,777 subjects were reviewed. The three largest intervention type categories were Relaxation Training (n=25), Cognitive Based Stress Management (n=22), and Hypnosis (n=21). Half the studies were conducted with healthy subjects (n=51). HIV (n=18), cancer (n=13) and allergies (n=7) were the most prominent conditions examined in the studies comprising of non-healthy subjects. Natural killer cell and CD4 T lymphocyte measures were the most commonly studied outcomes. Most outcome and modality categories had limited or inconclusive evidence. Relaxation training had the strongest scientific evidence of a mind-body medicine affecting immune outcomes. Immunoglobulin A had the strongest scientific evidence for positive effects from mind-body medicine. Issues for mind-body medicine studies with immune outcomes are discussed and recommendations are made to help improve future clinical trials.