High- and moderate-intensity training modify LPS-induced ex-vivo interleukin-10 production in obese men in response to an acute exercise bout

Direct assessment of leukocyte signalling and cytokine secretion reveals exercise intensity-dependent reductions in anti-inflammatory cytokine action

Circulating interleukin (IL)-6 and IL-10 concentrations are widely used to evaluate the anti-inflammatory effects of exercise but do not capture cytokine action at the cellular level. Whether and how acute exercise impacts anti-inflammatory cytokine action in humans is unknown. To determine how exercise intensity and pattern impact IL-6 and IL-10 action in blood leukocytes, 16 active adults (eight males/eight females; age: 30 ± 3 years; body mass index: 22.8 ± 2.3 kg/m2;V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ : 51 ± 6 mL/kg/min) completed a no-exercise control condition (CTL) or isocaloric bouts of cycling performed below (moderate continuous exercise; MCE) or above (heavy continuous or heavy intermittent exercise; HCE or HIE, respectively) lactate threshold. Venous blood (before, after, 30 min after and 90 min after exercise) was analysed for immune cell subpopulations, plasma cytokine concentrations, anti-inflammatory cytokine action and monocyte phenotype. Exercise induced rapid leukocytosis (P < 0.001) and increased plasma IL-6 (P < 0.001), IL-10 (P = 0.0145) and tumour necrosis factor-⍺ (TNF-⍺) (P = 0.0338) concentrations in an intensity-dependent manner (HCE and/or HIE vs. CTL). These systemic changes coincided with a diminished ability of IL-10/6 to phosphorylate STAT3 (P < 0.001) and inhibit TNF-⍺ secretion (P = 0.0238) in blood leukocytes following HCE and HIE. Monocyte polarization experiments revealed lower CD80 [MCE (P = 0.0933) and HIE (P = 0.0187) vs. CTL] and a tendency for higher CD163 expression (HCE vs. CTL, P = 0.0985), suggesting that hyporesponsiveness to anti-inflammatory cytokine action does not impede the ability of exercise to promote an anti-inflammatory monocyte phenotype. These findings provide novel insights into the immunomodulatory effects of exercise in humans and highlight the importance of directly measuring cellular cytokine action when evaluating the anti-inflammatory effects of exercise. KEY POINTS: Circulating cytokine concentrations are frequently used to evaluate the anti-inflammatory effects of exercise but may not capture changes in cytokine action occurring at the cellular level. We directly assessed anti-inflammatory cytokine action - measured using a combination of intracellular signalling and cytokine secretion ex vivo - in distinct immune cell subpopulations after acute calorie-matched exercise bouts differing in intensity and pattern. Anti-inflammatory cytokine action was blunted following higher intensity exercise despite corresponding increases in circulating cytokine concentrations and immune cell counts. Changes in cytokine action were not explained by changes in cytokine receptor expression on circulating immune cells. Our findings provide new insights into the immunomodulatory effects of exercise in humans and highlight the importance of directly measuring cellular cytokine action when evaluating the anti-inflammatory effects of exercise.

Effects of pre-sleep protein supplementation on plasma markers of muscle damage and inflammatory cytokines resulting from sprint interval training in trained swimmers

BACKGROUND

Pre-sleep protein has been shown to improve muscle recovery overnight following exercise-induced muscle damage. Whether such an approach affects recovery from sprint interval training (SIT) has yet to be elucidated. This study examined the effects of protein supplementation every night before sleep on early (45 min post-SIT) and late (24 and 48 h after SIT) responses of creatine kinase (CK) and inflammatory cytokines, including interleukin-6 and 10 (IL-6 and IL-10) and tumor necrosis factor-alpha (TNFα).

METHODS

Twenty trained swimmers underwent a 2-week in-water swimming SIT (two sets of 12 × 50-m all-out swims, interspersed by 1:1 recovery between each sprint and 3 min of rest between sets) and were randomized to two intervention groups receiving either 0.5 g kg-1 day-1 protein beverage (PRO) or the same amount of carbohydrate (CHO) preceding going to bed every night. For initial and final training sessions, CK and cytokine responses were analyzed at different time points, including resting, immediately after completion, 45 min post-SIT, and 24 and 48 h after SIT.

RESULTS

CK concentrations elevated from resting point to 24 and 48 h post-SIT for both PRO and CHO groups (p < 0.05). In both training groups, the peak levels of IL-6 and 10 were observed 45 min post-SIT on both occasions. TNFα levels significantly elevated from rest to immediately after SIT (p < 0.001) and returned to values equivalent to the baseline afterward in both groups and on both occasions. In both groups, swimming SIT also switched the cytokine response 48 hours after exercise to an anti-inflammatory status by decreasing the ratio of IL-6 to IL-10 (p < 0.04) in the last training session.

CONCLUSIONS

Pre-sleep protein ingestion failed to ameliorate blood markers of muscle damage. The late anti-inflammatory profile of cytokines and exercise-induced muscle damage improved after two weeks of swimming SIT with either protein or carbohydrate ingestion before sleep.

Effect of high-intensity interval training compared to moderate-intensity continuous training on body composition and insulin sensitivity in overweight and obese adults: A systematic review and meta-analysis

Objective

To compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on adults with overweight and obesity. Outcomes, including changes in insulin sensitivity, weight, body mass index (BMI), waist circumference, and body fat, were analyzed.

Methods

A systematic literature review was conducted. This review is registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42021281899. Clinical trials involving individuals who are overweight and obese and comparing HIIT with MICT effects on insulin sensitivity, weight, BMI, body fat percentage, and waist circumference were included. PubMed, Web of Science, Embase, and Scopus databases were searched using controlled vocabulary and free-text terms related to HIIT, obesity, and overweight. The search included studies published until September 2022. The Rob2 tool was used to assess the risk of bias. The results were presented through meta-analyses that provided summary estimators and confidence intervals. Subgroup analyses were conducted to assess the effect of the risk of bias on the outcomes. This research did not receive any specific funding.

Results

Of the 2534 articles, 30 met the eligibility criteria. The intervention duration ranged from 4 to 16 weeks. The observed effects for each outcome were as follows: insulin sensitivity (p = 0.02), weight (p = 0.58), BMI (p = 0.53), waist circumference (p = 0.87), body fat percentage (p = 0.07), body fat mass in kilograms (p = 0.39). The level of evidence obtained was moderate except for waist circumference, which was rated as low. Limitations included heterogeneity in training protocols, measurements, and study duration. Additionally, a risk of bias was identified in these studies.

Conclusion

HIIT and MICT did not significantly differ in their effects on weight, BMI, waist circumference, or body fat mass in adults with overweight and obesity. However, a moderate beneficial effect of HIIT was observed on insulin sensitivity. Therefore, further evidence is required to confirm these findings.

The influence of physical activity level and cytomegalovirus serostatus on the cytokine levels of young individuals

The practice of physical activity (PA) is a non-pharmacological variable that alters the immune response through changes in cytokines and cellular immunity. Inversely latent cytomegalovirus (CMV) infection prematurely ages the immune system and contributes to the chronic inflammatory condition in several diseases and in aging. This study aimed to compare the association of the PA level and CMV serostatus on whole blood mitogen-stimulated cytokine production of young individuals. The resting blood samples were collected from 100 volunteers of both sexes assigned to one of six groups according to the degree of PA and CMV serostatus: sedentary CMV- (n = 15), moderate physical activity CMV- (moderate PA CMV -, n = 15), high physical activity CMV- (high PA CMV-, n = 15), sedentary CMV+ (n = 20), moderate physical activity CMV + (moderate PA CMV+, n = 20) and high physical activity CMV + (high PA CMV +, n = 20). The collected peripheral blood got diluted in supplemented RPMI-1640 culture medium and incubated for 48 hours with a 2% concentration of phytohemagglutinin at 37ºC and CO2 at 5%. The supernatants were collected and used for the IL-6, IL-10, TNF-α, and INF-γ analysis by the ELISA method. The IL-10 concentration was higher in the Moderate PA and High PA groups when compared to the sedentary group, regardless of CMV status. The physically active (moderate and high PA) CMV+ individuals presented lower concentrations of IL-6 and TNF-α compared to CMV+ sedentary individuals, and the sedentary CMV+ subjects had a higher concentration of INF-γ compared to Sedentary CMV- subjects (p < 0.05). In summary, it is possible to infer that PA is key to controlling inflammation related to CMV infection. The stimulation of physical exercise is an important factor in controlling many diseases at the populational level.

The impact of high-intensity interval training on postprandial glucose and insulin: A systematic review and meta-analysis

AIMS

We performed a systematic review and meta-analysis to investigate the effects of high-intensity interval training (HIIT) on postprandial glucose (PPG) and insulin (PPI) versus non-exercise control and moderate-intensity continuous training (MICT) in participants with both normal and impaired glucose.

METHODS

The PubMed, Scopus, and Web of Science electronic databases were searched up to October 2021 for randomized trials evaluating HIIT versus control and/or versus MICT on glucose and insulin AUC using oral glucose tolerance testing. Subgroup analyses based on intervention duration (short-duration < 8 weeks, moderate-duration ≥ 8 weeks), baseline glucose levels (normal glucose and impaired glucose) and type of HIIT (L-HIIT and SIT) were also conducted across included studies.

RESULTS

A total of 25 studies involving 870 participants were included in the current meta-analysis. HIIT effectively reduced glucose [-0.37 (95% CI -0.60 to -0.13), p = 0.002] and insulin [-0.36 (95% CI -0.68 to -0.04), p = 0.02] AUC when compared with a CON group. Reductions in glucose AUC were significant for those with impaired glucose at baseline (p = 0.03), but not for those with normal glucose levels (p = 0.11) and following moderate-duration (p = 0.01), but not short-duration interventions (p = 0.18). However, there were no differences in glucose (p = 0.76) or insulin (p = 0.43) AUC between HIIT and MICT intervention arms.

CONCLUSIONS

Our results demonstrated that both HIIT and MICT are effective for reducing postprandial glycemia and insulinemia, particularly by moderate-duration interventions, and in those with impaired glucose.

Impact of 12-Week Moderate-Intensity Aerobic Training on Inflammasome Complex Activation in Elderly Women

Aging often associates with a chronic low-grade inflammatory status that can be consequent to the activation of Toll-like receptors (TLRs) and the downstream NLR family pyrin domain containing 3 (NLRP3) inflammasome and causes a chronic secretion of pro-inflammatory cytokines. Since exercise has known anti-inflammatory effects, we investigated the effect of Nordic walking training on inflammasome activation and downstream effectors in elderly women. A population of elderly women was divided into EXP (n = 29) that completed 12 weeks of the moderate-intensity aerobic training program and CTRL (n = 29), performing no activity. Blood samples were taken before and after the first (T1-pre and T1-post, respectively) and last (T2-pre and T2-post, respectively) exercise unit. Inflammasome activation status was assessed by whole blood NLRP3 and TLR4 expression by RT-qPCR. Serum levels of IL-1β, IL-6, TNFα, and IL-18 cytokines were assayed by multiplex fluorescent beads-based immunoassays or ELISA. NLRP3 and TLR4 levels were reduced 2 folds between T1-pre and T2-pre and induced at T2-post, compared to T2-pre, by 2.6- and 2.9-fold, respectively. A single exercise bout elicited a 1. 38-, 1. 5-, and 1.36-fold rise of IL-1β, TNFα, and IL-6 concentration, respectively, although not significant, at the beginning of the training (T1-pre vs. T1-post), a 1.4-fold decrease for IL-1β and TNFα at the end of the training (T1-pre vs. T2-pre), and a 2-, 1.8- and 1.26-fold increase after the last exercise session (T2-pre vs. T2-post) for the three cytokines. When stratifying the population based on BMI in normal weight (NW) and overweight (OW), NLRP3 and TLR4 expression was affected only in NW. As for inflammatory cytokines, IL-1β was modulated in NW at the beginning of the training, whereas in OW at the end of the training; for TNFα, this time-dependent modulation was significant only in OW. Applied aerobic training affected the resting expression of inflammasome constituents (NLRP3 and TLR4) and levels of downstream effectors (IL-1β, TNFα, and IL-6). However, at the end of the program, participants acquire an acute inflammatory response to exercise that was absent at baseline. Future studies would have to define the molecular mechanisms associated with, and how to potentiate, the exercise-associated inflammatory response.

Higher Muscle Damage Triggered by Shorter Inter-Set Rest Periods in Volume-Equated Resistance Exercise

Objectives

The aim of the manuscript was to analyze the effects of two rest periods between volume-equated resistance exercise (RE) on inflammatory responses (cytokines and leukocyte) and muscle damage.

Methods

Ten trained men (26.40 ± 4.73 years, 80.71 ± 8.95 kg, and 176.03 ± 6.11 cm) voluntarily participated in training sessions consisting of five sets of 10 reps performed at 10-RM on (1) the barbell bench press followed by (2) leg press, with either 1- or 3-min rest between sets and exercises. Circulating concentrations of different biomarkers was measured before (Pre), and after 3 h (excepted for cytokines), 6, 12, and 24 h from exercise. The rate of perceived exertion (RPE) was recorded after each set on both planned visits.

Results

We found greater increases triggered by the 1-min rest period in Creatine Kinase (CK), occurring from 12 to 24 h post-exercise compared to the 3-min rest condition. A significant increase in the 1-min rest condition was also observed in the total number of leukocytes, neutrophils, and monocytes. The 1-min rest period also triggered increases compared to baseline in pro-inflammatory cytokines [Interleukin 1 beta (IL-1β), p = 0.004; tumor necrosis factor α (TNF-α), p = 0.01; and granulocyte-macrophage colony-stimulating factor (GM-CSF), p = 0.01], which were more evident after 6 and 12 h post-exercise. Similarly, increases in anti-inflammatory cytokines [Interleukin 5 (IL-5), p = 0.01; Interleukin 6 (IL-6), p = 0.01; and Interleukin 10 (IL-10), p = 0.01] at all time-points were observed.

Conclusion

Our results indicate that a 1-min rest condition in volume-equated RE promoted greater overall muscle tissue damage with a longer duration of the inflammatory processes compared to a 3-min rest.

Type and Intensity as Key Variable of Exercise in Metainflammation diseases: A Review

Monocyte and lymphocyte subpopulations exhibit functions that vary between the anti- and pro-inflammatory spectrum, such as classic CD16- and non-classical CD16+ monocytes, as well as T helper 2 lymphocytes (Th2), the Th1/Th17 lymphocytes ratio, and T regulatory lymphocytes (Treg). Metabolic disease-associated inflammation is accompanied by an imbalance in monocyte and lymphocyte phenotypes and functionality, as well as a stronger proportion of inflammatory subpopulations. These changes appear to be important for the development and progression of diseases like diabetes and cardiovascular disease. On the other hand, the regular practice of physical exercise is an important tool to restore the functionality of monocytes and lymphocytes, and to balance the subtypes ratio. However, key variables regarding exercise prescription, such as the type of exercise, intensity, and volume differentially impact on the acute and chronic immune response in individuals diagnosed with meta inflammation diseases. Here, we discuss the impact of different physical exercise protocols, acutely and chronically, on monocytes and lymphocytes of individuals with metabolic disease-associated inflammation. In this review, we focus on the best effects of different exercise protocols to dose the "exercise pill" in different inflammatory status.

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.

Exercise Training Protocols to Improve Obesity, Glucose Homeostasis, and Subclinical Inflammation

The global pandemics of obesity and sedentarism are associated with poor quality of life and increased risks for development of inflammatory chronic diseases, including type 2 diabetes, cardiovascular diseases, and cancer. Physical activity is considered as an antidote to counteract the development of chronic sterile inflammatory diseases. Thus, we review the most promising exercise training protocols for promoting weight loss, improving glucose homeostasis, and reducing inflammation. We discuss the advantages and disadvantages of moderate-intensity continuous aerobic training, high-intensity aerobic training, and combined (aerobic + resistance) training. Our aim with this chapter is to provide evidence and guidance for choosing the most appropriate protocols of exercise training according to the goals of the patient.

Immunometabolic responses according to physical fitness status and lifelong exercise during aging: New roads for exercise immunology

Molecules such as cytokines, energetic substrates, and hormones found in the immune cell environment, especially lymphocytes and monocytes, are crucial for directing energy metabolism. In turn, changes in energy metabolism occur in a synchronized manner with the activation of certain signaling pathways, thereby this crosstalk is responsible for determining the functionality of immune cells. The immunometabolism field has grown over time and that is becoming increasingly promising in several populations; here we discuss the mechanisms involved in sedentary and physically active middle-aged individuals and master athletes. In this context, this review shows that the physical activity status and lifelong exercise seems to be good strategies for the promotion of metabolic and functional adaptations in T lymphocytes and monocytes, counteracting inflammatory environments caused by expanded adipose tissue and sedentary behavior, as well as delaying the immunosenescence caused by aging.

Differential effects of whole blood heat treatment on the ex vivo inflammatory profile of untrained and trained men

This study evaluated the effects of heat stress on the ex vivo inflammatory profile in untrained and trained men. Whole blood samples from untrained (UT) and trained (TR) individuals were incubated for 2 h at 37 °C or 40 °C. The whole blood of a subsample of the participants (n = 5 in both TR and UT groups) were stimulated with lipopolysaccharide (LPS, 10 ng/mL) concomitant to heat treatment (37 °C versus 40 °C). Flow cytometry was used to assess the intracellular NF-κB activation in CD4+ T cells and CD14+ monocytes, the expression of Toll-Like Receptor-4 (TLR-4), the frequencies of CD4+CD25-CD39+ and CD4+CD25+CD39+ T cells and monocyte subsets (CD14+CD16-; CD14+CD16+; CD14-CD16+), the mitochondrial membrane potential (MMP) and the reactive oxygen species (ROS) production by lymphocytes and monocytes. The production of interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) by LPS-stimulated whole blood were also evaluated. Heat treatment (40 °C) increased the proportions of CD14+CD16- and CD14+CD16+ monocytes and the lymphocyte MMP in the UT group. The frequencies of CD14-CD16+ monocytes and the activation of NF-κB in CD14+ monocytes decreased in UT and TR groups after heat treatment, while a reduction in CD4+CD25-CD39+ T-cells was observed only in the UT group. Higher TLR-4 and NF-κB activation were found in LPS-stimulated monocytes of UT men concomitant with higher TNF-α production and diminished IL-10 production after heat treatment. TR individuals presented lower NF- κB activation in LPS-stimulated monocytes after heat treatment. Our data suggest that the training status of individuals may impact on the anti-inflammatory response of heat treatment.

Effect of Exercise Intensity on Cell-Mediated Immunity

Moderate-intensity exercise is considered to enhance immune function and to be useful for preventing acute upper respiratory infections and similar conditions. Many people practice low-intensity short-duration exercise with the expectation of a beneficial effect on immunocompetency. However, it is difficult to affirm the existence of definite evidence of such a benefit. In this article, we discuss the effects of low-intensity short-duration exercise on cell-mediated immunity, and contrast them to the effects of high-intensity and long-duration exercise. Whereas high-intensity exercise induces inflammation and reduces cell-mediated immune system function, low-intensity exercise does not appear to have a large effect on either inflammation or cell-mediated immune function. Low-intensity exercises such as walking and yoga, which are helpful to relieve stress, cannot be considered as harmful to the immune system. Although yoga was shown to impose fewer restrictions on breathing and physical strain, the evidence that yoga enhances cell-mediated immunity remains insufficient. Therefore, further studies are needed to examine the exercise mode that may be most effective for improvement of immune functions.