Immunologic mediators as parameters of the reaction to strenuous exercise

Long-Distance Trail Running Induces Inflammatory-Associated Protein, Lipid, and Purine Oxidation in Red Blood Cells

Ultra-endurance exercise places extreme physiological demands on oxygen transport, yet its impact on red blood cells (RBCs) remains underexplored. We conducted a multi-omics analysis of plasma and RBCs from endurance athletes before and after a 40-km trail race (MCC) and a 171-km ultramarathon (UTMB®). Ultra-running led to oxidative stress, metabolic shifts, and inflammation-driven RBC damage, including increased acylcarnitines, kynurenine accumulation, oxidative lipid and protein modifications, reduced RBC deformability, enhanced microparticle release, and decreased hematocrit - hallmarks of accelerated RBC aging and clearance. Post-race interleukin-6 strongly correlated with kynurenine elevation, mirroring inflammatory responses in severe infections. These findings challenge the assumption that RBC damage in endurance exercise is primarily mechanical, revealing systemic inflammation and metabolic remodeling as key drivers. This study underscores RBCs as both mediators and casualties of extreme exercise stress, with implications for optimizing athlete recovery, endurance training, and understanding inflammation-linked RBC dysfunction in clinical settings. Teaser Marathon running imparts molecular damage to red blood cells, the effects of which are exacerbated by increased distances of ultramarathons.

Physiology and Pathophysiology of Marathon Running: A narrative Review

BACKGROUND

Marathon training and running have many beneficial effects on human health and physical fitness; however, they also pose risks. To date, no comprehensive review regarding both the benefits and risks of marathon running on different organ systems has been published.

MAIN BODY

The aim of this review was to provide a comprehensive review of the benefits and risks of marathon training and racing on different organ systems. A predefined search strategy including keywords (e.g., marathon, cardiovascular system, etc.) and free text search was used. Articles covering running regardless of sex, age, performance level, and event type (e.g., road races, mountain marathons) were considered, whereas articles examining only cycling, triathlon, stress-tests or other sports were excluded. In total, we found 1021 articles in PubMed, Scopus, and Google Scholar, of which 329 studies were included in this review. Overall, marathon training offers several benefits for different organ systems and reduces all-cause mortality. As such, it improves cardiovascular risk factors, leads to favorable cardiac adaptations, enhances lung function, and improves quality of life in chronic kidney disease patients. It also enhances gastrointestinal mobility and reduces the risk of specific tumors such as colorectal cancer and hepatocellular carcinoma. Marathon training enhances bone health and skeletal muscle metabolism. It further positively affects hematopoiesis and cytotoxic abilities of natural killer cells, and may act neuroprotective on a long-term basis. After a marathon, changes in biomarkers suggesting pathological events in certain organ systems such as cardiovascular, renal, gastrointestinal, liver, hematological, immune, musculoskeletal, central nervous, and endocrine systems can often be observed. Mostly, these changes are limited to 1-3 days post-race and usually normalize within a week. Moreover, marathon running poses the risk of serious adverse events such as sudden cardiac death or acute liver failure. Concerning lung function, a decrease after a marathon race was observed. Acute kidney injury, as well as electrolyte imbalances, are relatively common amongst marathon finishers. Many runners complain of gastrointestinal symptoms during or after long-distance running. Many runners suffer from running-related musculoskeletal injuries often impairing performance. A marathon is often accompanied by an acute inflammatory response with transient immunosuppression, making runners susceptible to infections. Also, hormonal alterations such as increased cortisol levels or decreased testosterone levels immediately after a race are observed. Disturbances in sleep patterns are commonly found in marathon runners leading up to or directly after the race.

CONCLUSION

All in all, marathon training is generally safe for human health and individual organ systems. Considering the high popularity of marathon running, these findings supply athletes, coaches, sports scientists, and sports medicine practitioners with practical applications. Further large-scale studies examining long-term effects on the cardiovascular, renal, and other system are needed.

Neurological mechanism-based analysis of the role and characteristics of physical activity in the improvement of depressive symptoms

Depression is a common mental disorder characterized by a high prevalence and significant adverse effects, making the searching for effective interventions an urgent priority. In recent years, physical activity (PA) has increasingly been recognized as a standard adjunctive treatment for mental disorders owing to its low cost, easy application, and high efficiency. Epidemiological data shows positive preventive and therapeutic effects of PA on mental illnesses such as depression. This article systematically describes the prophylactic and therapeutic effects of PA on depression and its biological basis. A comprehensive literature analysis reveals that PA significantly improves depressive symptoms by upregulating the expression of "exerkines" such as irisin, adiponectin, and BDNF to positively impacting neuropsychiatric conditions. In particular, lactate could also play a critical role in the ameliorating effects of PA on depression due to the findings about protein lactylation as a novel protein post-transcriptional modification. The literature also suggests that in terms of brain structure, PA may improve hippocampal volume, basal ganglia (neostriatum, caudate-crustal nucleus) and PFC density in patients with MDD. In summary, this study elucidates the multifaceted positive effects of PA on depression and its potential biological mechanisms with a particular emphasis on the roles of various exerkines. Future research may further investigate the effects of different types, intensities, and durations of PA on depression, as well as how to better integrate PA interventions into existing treatment strategies to achieve optimal outcomes in mental health interventions.

Myokines May Be the Answer to the Beneficial Immunomodulation of Tailored Exercise-A Narrative Review

Exercise can regulate the immune function, activate the activity of immune cells, and promote the health of the organism, but the mechanism is not clear. Skeletal muscle is a secretory organ that secretes bioactive substances known as myokines. Exercise promotes skeletal muscle contraction and the expression of myokines including irisin, IL-6, BDNF, etc. Here, we review nine myokines that are regulated by exercise. These myokines have been shown to be associated with immune responses and to regulate the proliferation, differentiation, and maturation of immune cells and enhance their function, thereby serving to improve the health of the organism. The aim of this article is to review the effects of myokines on intrinsic and adaptive immunity and the important role that exercise plays in them. It provides a theoretical basis for exercise to promote health and provides a potential mechanism for the correlation between muscle factor expression and immunity, as well as the involvement of exercise in body immunity. It also provides the possibility to find a suitable exercise training program for immune system diseases.

Pathophysiology of Physical Exercise in Kidney Patients: Unveiling New Players - The Role of Myokines

BACKGROUND

Chronic kidney disease (CKD) is a progressive systemic condition characterized by numerous complications. Among these, alterations in skeletal muscle physiology, such as sarcopenia, are particularly significant, as they are associated with poor outcomes and reduced quality of life.

SUMMARY

Various interventions, including pharmacological approaches and lifestyle modifications have been investigated to slow CKD progression and prevent or treat its complications. Physical exercise, in particular, has emerged as a promising intervention with multiple beneficial effects. These include improvements in physical functioning, increased muscle mass, modulation of metabolic abnormalities, and reduced cardiovascular risk. However, the pathophysiology of physical exercise in patients with kidney disease is complex and remains only partially understood. A crucial advancement in understanding this phenomenon has been the identification of myokines - molecules expressed and released by skeletal muscle in response to physical activity. These myokines can exert both paracrine and systemic effects, influencing not only skeletal muscle physiology but also other processes such as energy metabolism and lipid regulation.

KEY MESSAGES

The interplay among skeletal muscle, physical activity, and myokines may act as a pivotal regulator in various physiological processes, including aging, as well as in pathological conditions like cachexia and sarcopenia, frequently observed in CKD patients at different stages, including patients on dialysis. Despite the potential importance of this relationship, only a limited number of studies have explored the relationship between exercise and myokine, and the effect of this interaction on experimental models or individuals with kidney disease. In the following sections, we review and discuss this topic.

The Influence of Metabolism on Immune Response: A Journey to Understand Immunometabolism in the Context of Viral Infection

In recent years, the emergence of the concept of immunometabolism has shed light on the pivotal role that cellular metabolism plays in both the activation of immune cells and the development of immune programs. The antiviral response, a widely distributed defense mechanism used by infected cells, serves to not only control infections but also to attenuate their deleterious effects. The exploration of the role of metabolism in orchestrating the antiviral response represents a burgeoning area of research, especially considering the escalating incidence of viral outbreaks coupled with the increasing prevalence of metabolic diseases. Here, we present a review of current knowledge regarding immunometabolism and the antiviral response during viral infections. Initially, we delve into the concept of immunometabolism by examining its application in the field of cancer-a domain that has long spearheaded inquiries into this fascinating intersection of disciplines. Subsequently, we explore examples of immune cells whose activation is intricately regulated by metabolic processes. Progressing with a systematic and cellular approach, our aim is to unravel the potential role of metabolism in antiviral defense, placing significant emphasis on the innate and canonical interferon response.

ANGPTL4, IL-6 and TNF-α as regulators of lipid metabolism during a marathon run

The aim of the study was to reveal whether marathon running influences regulators of lipid metabolism i.e. angiopoietin-like protein 4 (ANGPTL4), interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α). Plasma concentration of ANGPTL4, IL-6, TNF-α and lipids were determined in samples collected from 11 male runners before the marathon, immediately after the run and at 90 min of recovery. Plasma ANGPTL4 increased during exercise from 55.5 ± 13.4 to 78.1 ± 15.0 ng/ml (P < 0.001). This was accompanied by a significant increase in IL-6, TNF-α, free fatty acids (FFA) and glycerol (Gly) and a decrease in triacylglycerols (TG). After 90 min of recovery ANGPTL4 and TG did not differ from the exercise values, while plasma IL-6, TNF-α, FFA and Gly concentration were significantly lower. The exercise-induced increase in plasma concentration of ANGPTL4 correlated positively with the rise in plasma IL-6, TNF-α, FFA and Gly and negatively with the duration of the run. The increase in plasma IL-6 and TNF-α correlated positively with the rise in Gly. Summarizing, marathon running induced an increase in plasma ANGPTL4 and the value was higher in faster runners. The increase in plasma FFA, IL-6 and TNF-α concentration during a marathon run may be involved in plasma ANGPTL4 release, which could be a compensatory mechanism against FFA-induced lipotoxicity and oxidative stress. All of the analyzed cytokines may stimulate lipolysis during exercise.

Acute and chronic effects of physical exercise on IgA and IgG levels and susceptibility to upper respiratory tract infections: a systematic review and meta-analysis

This systematic review and meta-analysis aimed at evaluating acute and chronic effects of physical exercise on IgA and IgG levels, as well as its relationship with the susceptibility to develop upper respiratory tract infections (URTI). This systematic review and meta-analysis was conducted and reported in accordance with PRISMA statement. A systematic search of PubMed, Web of Science, and EMBASE was performed in July 2020. This systematic review and meta-analysis included studies in which participants performed acute exercise or chronic physical training and were subjected to analyses of URTI incidence and concentrations of IgA and IgG. The selected studies for systematic review were divided into the following three groups: (I) trials that evaluated the effects of acute exercise in sedentary subjects, (II) trials that evaluated the effects of acute exercise in athletes/trained individuals, and (III) trials that evaluated the effects of chronic physical training on the incidence of URTI, as well as on the levels of IgA and IgG. Acute exercise increases the IgA levels in trained subjects but does not affect its levels in untrained subjects. Such increase in IgA levels induced by acute exercise is greater in trained individual that performed ultramarathon. On the other hand, chronic physical training reduces IgA levels in both trained and untrained subjects, does not change IgA levels in non-military subjects, besides from not affecting IgG levels. The present systematic review and meta-analysis indicates that acute exercise positively influences IgA levels in trained individuals, being this effect pronounced when a strenuous exercise such as ultramarathon is executed. Chronic physical training, in turn, does not affect IgG levels.

Histone Deacetylases as Modulators of the Crosstalk Between Skeletal Muscle and Other Organs

Skeletal muscle plays a major role in controlling body mass and metabolism: it is the most abundant tissue of the body and a major source of humoral factors; in addition, it is primarily responsible for glucose uptake and storage, as well as for protein metabolism. Muscle acts as a metabolic hub, in a crosstalk with other organs and tissues, such as the liver, the brain, and fat tissue. Cytokines, adipokines, and myokines are pivotal mediators of such crosstalk. Many of these circulating factors modulate histone deacetylase (HDAC) expression and/or activity. HDACs form a numerous family of enzymes, divided into four classes based on their homology to their orthologs in yeast. Eleven family members are considered classic HDACs, with a highly conserved deacetylase domain, and fall into Classes I, II, and IV, while class III members are named Sirtuins and are structurally and mechanistically distinct from the members of the other classes. HDACs are key regulators of skeletal muscle metabolism, both in physiological conditions and following metabolic stress, participating in the highly dynamic adaptative responses of the muscle to external stimuli. In turn, HDAC expression and activity are closely regulated by the metabolic demands of the skeletal muscle. For instance, NAD+ levels link Class III (Sirtuin) enzymatic activity to the energy status of the cell, and starvation or exercise affect Class II HDAC stability and intracellular localization. SUMOylation or phosphorylation of Class II HDACs are modulated by circulating factors, thus establishing a bidirectional link between HDAC activity and endocrine, paracrine, and autocrine factors. Indeed, besides being targets of adipo-myokines, HDACs affect the synthesis of myokines by skeletal muscle, altering the composition of the humoral milieu and ultimately contributing to the muscle functioning as an endocrine organ. In this review, we discuss recent findings on the interplay between HDACs and circulating factors, in relation to skeletal muscle metabolism and its adaptative response to energy demand. We believe that enhancing knowledge on the specific functions of HDACs may have clinical implications leading to the use of improved HDAC inhibitors for the treatment of metabolic syndromes or aging.

Dynamic Metabolic Response, Clotting Times and Peripheral Indices of Central Fatigue in Horse Competing in a 44 Km Endurance Race

A deep knowledge on metabolic response of athlete horse to exercise is of paramount importance for the development of optimal training programs to attain equilibrium between good performance and animal welfare. This study investigated the dynamic change of metabolic, clotting times and peripheral indices of central fatigue in horses competing in an official 44 km endurance race.  From 6 horses blood samples were collected at rest (T_PRE), within 5 minutes from the end of race (T_PE5), after 30, 60 minutes after the end of race (T_PE30 and T_PE60) to investigate the values of blood lactate, glucose, platelets (PLTs), serum leucine, isoleucine, valine, tryptophan, the ratio between tryptophan and branched-chain amino acids (BCAAs) levels (Try/BCAAs), total proteins, non-esterified fatty acids, plasma thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time and fibrinogen (Fb). Lactate, PLTs, non-esterified fatty acids, BCAAs and Try/BCAAs showed higher values at T_PE5, T_PE30and T_PE60than T_PRE(P < .0001); glucose showed lower values at T_PE5, T_PE30and T_PE60than T_PRE(P < .0001). Higher TT values were found at T_PE5, T_PE30and T_PE60than T_PRE, and at T_PE5than T_PE30 and T_PE60(P < .0001); Fb was higher at T_PE5than T_PRE, T _PE30and T_PE60(P < .0001). This survey confirms that horses performing prolonged physical exercise experienced glycolysis, lipid mobilization and amino acid metabolism to provide substrates as fuel for muscle contraction.

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.

Continuous Protein Supplementation Reduces Acute Exercise-Induced Stress Markers in Athletes Performing Marathon

The aim of this study was to determine the changes in endurance performance and metabolic, hormonal, and inflammatory markers induced by endurance stress (marathon race) in a combined strategy of training and dietary protein supplementation. The study was designed as a randomised controlled trial consisting of regular endurance training without and with a daily intake of a soy protein-based supplement over a three-month period in 2 × 15 (10 males and 5 females per group) endurance-trained adults. Body composition (body mass, BMI, and fat mass) was determined, and physical fitness was measured by treadmill ergometry at baseline and after 3 months of intervention; changes in exercise-induced stress and inflammatory markers (CK, myoglobin, interleukin-6, cortisol, and leukocytes) were also determined before and after a marathon competition; eating behaviour was documented before and after intervention by a three-day diet diary. Although no significant influence on endurance performance was observed, the protein supplementation regime reduced the exercise-induced muscle stress response. Furthermore, a protein intake of ≥20% of total energy intake led to a lower-level stress reaction after the marathon race. In conclusion, supplementary protein intake may influence exercise-induced muscle stress reactions by changing cellular metabolism and inflammatory pathways.

Effect of Various Exercise Regimens on Selected Exercise-Induced Cytokines in Healthy People

Different forms of physical activity—endurance, resistance or dynamic power—stimulate cytokine release from various tissues to the bloodstream. Receptors for exercise-induced cytokines are present in muscle tissue, adipose tissue, liver, brain, bones, cardiovascular system, immune system, pancreas, and skin. They have autocrine, paracrine and endocrine activities. Many of them regulate the myocyte growth and differentiation necessary for muscle hypertrophy and myogenesis. They also modify energy homeostasis, lipid, carbohydrate, and protein metabolism, regulate inflammation and exchange information (crosstalk) between remote organs. So far, interleukin 6 and irisin have been the best studied exercise-induced cytokines. However, many more can be grouped into myokines, hepatokines and adipomyokines. This review focuses on the less known exercise-induced cytokines such as myostatin, follistatin, decorin, brain-derived neurotrophic factor, fibroblast growth factor 21 and interleukin 15, and their relation to various forms of exercise, i.e., acute vs. chronic, regular training in healthy people.

Acute and Chronic Catabolic Responses to

Given the wide variety of conditioning program trainings employed, the present study compared the catabolic effects induced by CrossFit^® and resistance training in moderately trained subjects. Twenty males joined either the CrossFit^® group (n = 10; 30 min/day of “workout of the day”) or the resistance training (RT) group (n = 10; 30 min/day of resistance exercises) thrice a week, for 8 weeks. Salivary levels of cortisol, interleukin 1-beta (IL-1β), and uric acid were assessed via enzyme-linked immunosorbent assays before (PRE) and 30-min after (POST) SESSION 1 and SESSION 24. Variables’ percentual changes were computed as (POST-PRE)/PRE*100 in each session (Δ%). CrossFit^® acutely increased cortisol levels in both sessions, with a significant decrease in Δ%cortisol from SESSION 1 to 24. In the RT group, cortisol values decreased in both sessions, only acutely. A significant decrease in IL-1β levels was registered acutely in both groups, in both sessions, whereas Δ%IL-1β was not different between the two groups. While uric acid levels increased in both groups acutely, a chronic downregulation of Δ%uric acid, from SESSION 1 to 24, was appreciated for the RT group only. Overall, CrossFit^® appeared to induce more intense effects than the RT program as to the investigated catabolic responses.

Impact of knee joint loading on fragmentation of serum cartilage oligomeric matrix protein

The aim of the study was to examine the effect of mechanical knee joint loading on the fragmentation pattern of serum cartilage oligomeric matrix protein (COMP). Ten healthy men ran with knee orthoses that were passive or active (+30.9 N·m external flexion moments) on a treadmill (30 minute; v = 2.2 m/s). Lower-limb mechanics, serum COMP levels, and fragmentation patterns (baseline; 0, 0.5, 1, 2 hours postrunning) were analyzed. Running with active orthoses enhanced knee flexion moments, ankle dorsiflexion, and knee flexion angles (P < .05). There was an increase in serum COMP (+25%; pre: 8.9 ± 2.4 U/l; post: 10.7 ± 1.9 U/l, P = .001), COMP pentamer/tetramer (+88%; 1.88 ± 0.81, P = .007), trimer (+209%; 3.09 ± 2.65, P = .005), and monomer (+78%; 1.78 ± 0.85, P = .007) after running with passive orthoses and in serum COMP (+41%; pre: 8.5 ± 2.7 U/l; post: 11.3 ± 2.1 U/l, P < .001), COMP pentamer/tetramer (+57%; 1.57 ± 0.39, P = .007), trimer (+86%; 1.86 ± 0.47, P = .005), and monomer (+19%; 1.19 ± 0.34, P = .114) after running with active orthoses. Increased fragmentation might indicate COMP release from cartilage while running. Interestingly, 0.5 h up to 2 hours after running with passive orthoses, trimer (0.5 hour: 2.73 ± 3.40, P = .029; 2 hours: 2.33 ± 2.88, P = .037), and monomer (0.5 hour: 2.23 ± 2.33, P = .007; 1 hour: 2.55 ± 1.96, P = .012; 2 hours: 2.65 ± 2.50, P = .009) increased while after running with active orthoses, pentamer/tetramer (1 hour: 0.79 ± 0.28, P = .029), and trimer (1 hour: 0.63 ± 0.14, P = .005; 2 hours: 0.68 ± 0.34, P = .047) decreased. It seems that COMP degradation and clearance vary depending on joint loading characteristics.

Training Program Intensity Induces an Acute Phase Response in Clinically Healthy Horses

Physiological and hematochemical changes associated with exercise have been extensively investigated in equine species. It is known that stress elevates circulating levels of acute phase proteins (APPs). This survey evaluated whether horses trained with different training programs exhibit changes in APP levels after exercise event. Twenty Saddle Italian horses (11 geldings and 9 females, 9 ± 1 years old, body weight of 425 ± 35 kg) were divided into two equal groups according to the intensity of training programs they were subjected: group A was subjected to an intense training program, group B was subjected to a moderate training program. At the end of the training period, horses were subjected to a simulated exercise event (show jumping course of 400 m length with 12 obstacles). From horses, blood samples were collected at rest conditions (T_REST) and after 12 and 24 hour from the end of exercise (T_{12 h} and T_{24 h}); the concentration of serum amyloid A (SAA), haptoglobin, albumin, total proteins, iron, and fibrinogen was assessed. The circulating levels of SAA, fibrinogen, and iron were influenced by simulated exercise event (P < .01), starting from 12 hour after the end of exercise, suggesting the onset of an acute phase-like response, and it would seem that training program intensity the horses underwent also affected the degree of response, although only SAA values were significantly different between groups (P < .001). The findings obtained suggest that jumping exercise induces an acute phase response; however, further studies are advocated to better evaluate mechanisms by which exercise activates this response in the athletic horse.

The Impact of Resveratrol Supplementation on Inflammation Induced by Acute Exercise in Rats: Il6 Responses to Exercise

Severe physical activity leads to a sharp increase in free radicals, an oxidative stress, inflammation, and tissue damage. Resveratrol as one of the antioxidants can be effective in preventing the effects of oxidative stress. Therefore, the present study was aimed to evaluate the effect of trans-resveratrol supplementation and training exercise on inflammation-related factors. Sixty-four male Wistar rats were divided into six groups, each group consisting of 16 animals: 1) excursive + trans-resveratrol, 2) exercise group, 3) trans-resveratrol group, and 4) control group. Following the familiarization sessions, a more consistent protocol with an intensity of 65% vo2 max was performed for 12 weeks. Afterward, half of the mice in each group received acute exercise training with an intensity of 70-75% of vo2 max at the age of 20 weeks, until reaching the disability level. Finally, the levels of inflammatory markers were measured using special kits. Our findings depicted that inflammatory factors such as CPR, TNF-α, IL-6, and IL-7 were not affected by endurance protocol (P > 0.05), whereas, they were significantly increased by acute exercise training (P > 0.05). Additionally, we found that RES supplements led to a decrease in CPR and IL-6 levels, while not affecting TNF-α and IL-17 levels. According to available evidence, RES appears to have anti-inflammatory and protective effects during exercise by reducing inflammatory factors. Further studies are required to clarify the role of trans-resveratrol supplementation after exercise training.

The Physiological Effect of n-3 Polyunsaturated Fatty Acids (n-3 PUFAs) Intake and Exercise on Hemorheology, Microvascular Function, and Physical Performance in Health and Cardiovascular Diseases; Is There an Interaction of Exercise and Dietary n-3 PUFA Intake?

Physical activity has a beneficial effect on systemic hemodynamics, physical strength, and cardiac function in cardiovascular (CV) patients. Potential beneficial effects of dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs), such as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid on hemorheology, vascular function, inflammation and potential to improve physical performance as well as other CV parameters are currently investigated. Recent meta-analysis suggests no effect of n-3 PUFA supplementation on CV function and outcomes of CV diseases. On the other hand, some studies support beneficial effects of n-3 PUFAs dietary intake on CV and muscular system, as well as on immune responses in healthy and in CV patients. Furthermore, the interaction of exercise and dietary n-3 PUFA intake is understudied. Supplementation of n-3 PUFAs has been shown to have antithrombotic effects (by decreasing blood viscosity, decreasing coagulation factor and PAI-1 levels and platelet aggregation/reactivity, enhancing fibrinolysis, but without effects on erythrocyte deformability). They decrease inflammation by decreasing IL-6, MCP-1, TNFα and hsCRP levels, expression of endothelial cell adhesion molecules and significantly affect blood composition of fatty acids. Treatment with n-3 PUFAs enhances brachial artery blood flow and conductance during exercise and enhances microvascular post-occlusive hyperemic response in healthy humans, however, the effects are unknown in cardiovascular patients. Supplementation of n-3 PUFAs may improve anaerobic endurance and may modulate oxygen consumption during intense exercise, may increase metabolic capacity, enhance endurance capacity delaying the onset of fatigue, and improving muscle hypertrophy and neuromuscular function in humans and animal models. In addition, n-3 PUFAs have anti-inflammatory and anti-nociceptive effects and may attenuate delayed-onset muscle soreness and muscle stiffness, and preserve joint mobility. On the other hand, effects of n-3 PUFAs were variably observed in men and women and they vary depending on dietary protocol, type of supplementation and type of sports activity undertaken, both in healthy and cardiovascular patients. In this review we will discuss the physiological effects of n-3 PUFA intake and exercise on hemorheology, microvascular function, immunomodulation and inflammation and physical performance in healthy persons and in cardiovascular diseases; elucidating if there is an interaction of exercise and diet.

Exercise and Vitamin D Supplementation Modify Spleen Morphology in Lean, but not, in Monosodium-Glutamate-Obese Rats

We evaluated the effect of exercise and vitamin D supplementation on histological aspects of the spleens of lean and obese rats. Male Wistar rats received neonatal administration of monosodium glutamate (MSG; 4g/Kg), while Control (CON) rats received an equimolar solution. At 30 days of age, CON and MSG rats were subdivided into Exercised (E) or Sedentary (S) groups and Vitamin D (VD; 12µg/Kg) supplemented or non-supplemented (NS) groups. At the 86th day of life, rats were euthanized, and their body weights and adiposity were evaluated. Spleens were submitted to histomorphometric analysis of the white pulp (WP), germinal center (GC) and lymphatic nodule (LN). Data are presented as mean ± SEM (p<0.05). MSG treatment promoted a reduction in spleen weight, increased LN thickness and WP area, but reduced GC occupation, compared to spleens of CON-lean rats (p<0.05). Exercise and VD did not provoke changes in the spleens of MSG-obese rats. In CON-lean rats, E and VD induced augmentation of LN thickness. VD supplementation increased the WP area, while E reduced GC area occupation in spleens of CON-lean rats (p<0.05). In conclusion, exercise and VD supplementation increased LN thickness and WP area, but had the opposite effect on the GC in spleens of CON-lean rats. However, neither exercise nor VD supplementation prevented the development of morphological abnormalities in the spleens of MSG-obese rats.

The compelling link between physical activity and the body's defense system

This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators: (1) acute and chronic effects of exercise on the immune system, (2) clinical benefits of the exercise-immune relationship, (3) nutritional influences on the immune response to exercise, and (4) the effect of exercise on immunosenescence. These scientific discoveries can be organized into distinctive time periods: 1900-1979, which focused on exercise-induced changes in basic immune cell counts and function; 1980-1989, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and increased risk of upper respiratory tract infections; 1990-2009, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and 2010 to the present, when technological advances in mass spectrometry allowed system biology approaches (i.e., metabolomics, proteomics, lipidomics, and microbiome characterization) to be applied to exercise immunology studies. The future of exercise immunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the personalized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases.

REDD1 induction regulates the skeletal muscle gene expression signature following acute aerobic exercise

The metabolic stress placed on skeletal muscle by aerobic exercise promotes acute and long-term health benefits in part through changes in gene expression. However, the transducers that mediate altered gene expression signatures have not been completely elucidated. Regulated in development and DNA damage 1 (REDD1) is a stress-induced protein whose expression is transiently increased in skeletal muscle following acute aerobic exercise. However, the role of this induction remains unclear. Because REDD1 altered gene expression in other model systems, we sought to determine whether REDD1 induction following acute exercise altered the gene expression signature in muscle. To do this, wild-type and REDD1-null mice were randomized to remain sedentary or undergo a bout of acute treadmill exercise. Exercised mice recovered for 1, 3, or 6 h before euthanization. Acute exercise induced a transient increase in REDD1 protein expression within the plantaris only at 1 h postexercise, and the induction occurred in both cytosolic and nuclear fractions. At this time point, global changes in gene expression were surveyed using microarray. REDD1 induction was required for the exercise-induced change in expression of 24 genes. Validation by RT-PCR confirmed that the exercise-mediated changes in genes related to exercise capacity, muscle protein metabolism, neuromuscular junction remodeling, and Metformin action were negated in REDD1-null mice. Finally, the exercise-mediated induction of REDD1 was partially dependent upon glucocorticoid receptor activation. In all, these data show that REDD1 induction regulates the exercise-mediated change in a distinct set of genes within skeletal muscle.

Physical activity and autoimmune diseases: Get moving and manage the disease

Physical activity, by definition, is any skeletal muscle body movement that results in energy expenditure. In the last few decades, a plethora of scientific evidences have accumulated and confirmed the beneficial role of physical activity as a modifiable risk factor for a wide variety of chronic diseases including cardiovascular diseases (CVDs), diabetes mellitus and cancer, among others. Autoimmune diseases are a heterogeneous group of chronic diseases, which occur secondary to loss of self-antigen tolerance. With the advent of biological therapies, better outcomes have recently been noted in the management of autoimmune diseases. Nonetheless, recent research highlights the salient role of modifiable behaviors such as physical inactivity on various aspects of the immune system and autoimmune diseases. Physical activity leads to a significant elevation in T-regulatory cells, decreased immunoglobulin secretion and produces a shift in the Th1/Th2 balance to a decreased Th1 cell production. Moreover, physical activity has been proven to promote the release of IL-6 from muscles. IL-6 released from muscles functions as a myokine and has been shown to induce an anti-inflammatory response through IL-10 secretion and IL-1β inhibition. Physical activity has been shown to be safe in most of autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), inflammatory bowel diseases (IBD), as well as others. Additionally, the incidence of RA, MS, IBD and psoriasis has been found to be higher in patients less engaged in physical activity. As a general trend, patients with autoimmune diseases tend to be less physically active as compared to the general population. Physically active RA patients were found to have a milder disease course, better cardiovascular disease (CVD) profile, and improved joint mobility. Physical activity decreases fatigue, enhances mood, cognitive abilities and mobility in patients with MS. In SLE patients, enhanced quality of life and better CVD profile were documented in more physically active patients. Physically active patients with type 1 diabetes mellitus have a decreased risk of autonomic neuropathy and CVD. Both fibromyalgia and systemic sclerosis patients report decreased disease severity, pain, as well as better quality of life with more physical activity. Further, SSc patients improve their grip strength, finger stretching and mouth opening with increased level of exercise. The purpose of this paper is to review the clinical evidence regarding the safety, barriers to engagement, and impact of physical activity on autoimmune diseases.

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.

Placenta Peptide Can Protect Mitochondrial Dysfunction through Inhibiting ROS and TNF-α Generation, by Maintaining Mitochondrial Dynamic Network and by Increasing IL-6 Level during Chronic Fatigue

Background: Level of fatigue is related to the metabolic energy available to tissues and cells, mainly through mitochondrial respiration, as well fatigue is the most common symptom of poorly functioning mitochondria. Hence, dysfunction of these organelles may be the cause of the fatigue seen in Chronic fatigue (CF). Placenta has been used for treatment of fatigue and various disease, moreover peptides has known protect mitochondrial viability, and alleviate fatigue. These properties of placenta and peptides may link with its effect on mitochondria; therefore, it is highly important to investigate the effectiveness of placenta peptide on fatigue and mitochondrial dysfunction. Methods: After administration of sheep placenta peptide (SPP) for 1 month, mice's were forced to swim till exhaustion for 90 min to induce chronic fatigue. Electron microscopic examination of skeletal muscle mitochondrial structure, tissue Malondialdehyde (MDA), mitochondrial SOD and serum inflammatory cytokines level were investigated in order to determine the potential effect of SPP on mitochondria during CF. Rat skeletal muscle (L6 cell) were also treated with different concentration of SPP to determine the effect of SPP on cell viability using Thiazoyl blue tetrazolium assay. Results: Our finding revealed that forced swimming induced fatigue model can cause mitochondrial damage through Reactive oxygen species (ROS) mediated lipid peroxidation and Tumor Necrosis factor alpha (TNF-α) elevation. Whereas SPP protected fatigue induced mitochondrial dysfunction through preventing ROS and TNF-α generation, by maintaining mitochondrial dynamic network and by increasing serum IL-6 level. Conclusion: SPP can protect damage in mitochondrial components which will allow proper functioning of mitochondria that will in turn inhibit progression of chronic fatigue. Therefore, SPP may represent a novel therapeutic advantage for preventing mitochondrial dysfunction in patients with chronic fatigue.

Effects of G-trainer, cycle ergometry, and stretching on physiological and psychological recovery from endurance exercise

The purpose of this study was to compare the effectiveness of 3 treatment modes (Anti-Gravity Treadmill [G-trainer], stationary cycling [CompuTrainer], and static stretching) on the physiological and psychological recovery after an acute bout of exhaustive exercise. In a crossover design, 12 aerobically trained men (21.3 ± 2.3 years, 72.1 ± 8.1 kg, 178.4 ± 6.3 cm, (Equation is included in full-text article.): 53.7 ± 6.3 ml·kg·min) completed a 29-km stationary cycling time trial. Immediately after the time trial, subjects completed 30 minutes of G-trainer or CompuTrainer (40% (Equation is included in full-text article.)) or static stretching exercises. A significant time effect was detected for plasma lactate (p = 0.010) and serum cortisol (p = 0.039) after exercise. No treatment or treatment by time interaction was identified for lactate or cortisol, respectively. No main effects for time, treatment, or treatment by time interaction were identified for interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α). No differences were observed among treatments in skeletal muscle peak power output, mean power output, time to peak power, and rate to fatigue at 24 hours postexercise bout. Finally, no significant changes in mood status were observed after exercise and between treatment groups. When compared with stationary cycling and static stretching, exercise recovery performed on the G-trainer was unable to reduce systemic markers of stress and inflammation, blood lactate, or improve anaerobic performance and psychological mood states after an exhaustive bout of endurance exercise. Further research is warranted that includes individualized recovery modalities to create balances between the stresses of training and competition.

Cold applications for recovery in adolescent athletes: a systematic review and meta analysis

Recovery and regeneration modalities have been developed empirically over the years to help and support training programmes aimed at maximizing athletic performance. Professional athletes undergo numerous training sessions, characterized by differing modalities of varying volumes and intensities, with the aim of physiological adaptation leading to improved performance. Scientific support to athletes focuses on improving the chances of a training programme producing the largest adaptive response. In competition it is mainly targeted at maximizing the chances of optimal performance and recovery when high performance levels are required repeatedly in quick succession (e.g. heats/finals). In recent years, a lot of emphasis has been put on recovery modalities. In particular, emphasis has been placed on the need to reduce the delayed onset of muscle soreness (DOMS) typically evident following training and competitive activities inducing a certain degree of muscle damage. One of the most used recovery modalities consists of cold-water immersion and/or ice/cold applications to muscles affected by DOMS. While the scientific literature has provided a rationale for such modalities to reduce pain in athletes and recreationally active adults, it is doubtful if this rationale is appropriate to aid training with adolescent athletes. In particular, since these methods have been suggested to potentially impair the muscle remodeling process leading to muscle hypertrophy. While this debate is still active in the literature, many coaches adopt such practices in youth populations, simply transferring what they see in elite sportspeople directly; without questioning the rationale, safety or effectiveness as well as the potential for such activity to reduce the adaptive potential of skeletal muscle remodeling in adolescent athletes. The aim of this review was to assess the current knowledge base on the use of ice/cold applications for recovery purposes in adolescent athletes in order to provide useful guidelines for sports scientists, medical practitioners, physiotherapists and coaches working with such populations as well as developing research questions for further research activities in this area. Based on the current evidence, it seems clear that evidence for acute benefits of such interventions are scarce and more work is needed to ascertain the physiological implications on a pre or peri-pubertal population.

The effect of turmeric (Curcumin) supplementation on cytokine and inflammatory marker responses following 2 hours of endurance cycling

BACKGROUND

Endurance exercise induces IL-6 production from myocytes that is thought to impair intracellular defence mechanisms. Curcumin inhibits NF-κB and activator protein 1, responsible for cytokine transcription, in cell lines. The aim of this study was to investigate the effect of curcumin supplementation on the cytokine and stress responses following 2 h of cycling.

METHODS

Eleven male recreational athletes (35.5 ± 5.7 years; Wmax 275 ± 6 W; 87.2 ± 10.3 kg) consuming a low carbohydrate diet of 2.3 ± 0.2 g/kg/day underwent three double blind trials with curcumin supplementation, placebo supplementation, and no supplementation (control) to observe the response of serum interleukins (IL-6, IL1-RA, IL-10), cortisol, c-reactive protein (CRP), and subjective assessment of training stress. Exercise was set at 95% lactate threshold (54 ± 7% Wmax) to ensure that all athletes completed the trial protocol.

RESULTS

The trial protocol elicted a rise in IL-6 and IL1-RA, but not IL-10. The supplementation regimen failed to produce statistically significant results when compared to placebo and control. IL-6 serum concentrations one hour following exercise were (Median (IQR): 2.0 (1.8-3.6) Curcumin; 4.8 (2.1-7.3) Placebo; 3.5 (1.9-7.7) Control). Differences between supplementation and placebo failed to reach statistical significance (p = 0.18) with the median test. Repeated measures ANOVA time-trial interaction was at p = 0.06 between curcumin supplementation and placebo. A positive correlation (p = 0.02) between absolute exercise intensity and 1 h post-exercise for IL-6 concentration was observed. Participants reported "better than usual" scores in the subjective assessment of psychological stress when supplementing with curcumin, indicating that they felt less stressed during training days (p = 0.04) compared to placebo even though there was no difference in RPE during any of the training days or trials.

CONCLUSION

The limitations of the current regimen and trial involved a number of factors including sample size, mode of exercise, intensity of exercise, and dose of curcumin. Nevertheless these results provide insight for future studies with larger samples, and multiple curcumin dosages to investigate if different curcumin regimens can lead to statistically different interleukin levels when compared to a control and placebo.

A subcutaneous adipose tissue-liver signalling axis controls hepatic gluconeogenesis

The search for effective treatments for obesity and its comorbidities is of prime importance. We previously identified IKK-ε and TBK1 as promising therapeutic targets for the treatment of obesity and associated insulin resistance. Here we show that acute inhibition of IKK-ε and TBK1 with amlexanox treatment increases cAMP levels in subcutaneous adipose depots of obese mice, promoting the synthesis and secretion of the cytokine IL-6 from adipocytes and preadipocytes, but not from macrophages. IL-6, in turn, stimulates the phosphorylation of hepatic Stat3 to suppress expression of genes involved in gluconeogenesis, in the process improving glucose handling in obese mice. Preliminary data in a small cohort of obese patients show a similar association. These data support an important role for a subcutaneous adipose tissue–liver axis in mediating the acute metabolic benefits of amlexanox on glucose metabolism, and point to a new therapeutic pathway for type 2 diabetes.

The drug amlexanox is known to improve obesity-related metabolic dysfunction in mice. Here the authors show that this effect is mediated by interleukin-6 secreted from subcutaneous adipocytes, which then inhibits gluconeogenesis in the liver by phosphorylating the hepatic transcription factor Stat3.

Effect of obesity and exercise on the expression of the novel myokines, Myonectin and Fibronectin type III domain containing 5

Metabolic dysfunction in skeletal muscle is a major contributor to the development of type 2 diabetes. Endurance exercise training has long been established as an effective means to directly restore skeletal muscle glucose and lipid uptake and metabolism. However, in addition to the direct effects of skeletal muscle on glucose and lipids, there is renewed interest in the ability of skeletal muscle to coordinate metabolic activity of other tissues, such as adipose tissue and liver. The purpose of this study was to examine the effects of endurance exercise on the expression level of two novel muscle-derived secreted factors, or myokines, Myonectin and Fibronectin type III domain containing 5 (FNDC5), the precursor for Irisin. Methods. We performed immunoblot analysis and quantitative real-time PCR analysis of Myonectin and FNDC5 in the diaphragm muscles of obese Zucker rat (OZR) and lean Zucker rat (LZR) with 9 weeks of aerobic training on a motorized treadmill. Results. We show that myonectin gene expression is increased in the OZR model of obesity and decreases with exercise in both lean and obese Zucker rats. Conversely, myonectin protein concentration was elevated with exercise. Similarly, FNDC5 mRNA levels are significantly higher in the OZR, however exercise training had no effect on the expression level of FNDC5 in either the LZR or OZR. We did not observe any difference in muscle protein content of Irisin with obesity or exercise. Conclusion. Our data shows that exercise training does not increase either FNDC5 or myonectin gene expression, indicating that increased transcriptional regulation of these myokines is not induced by exercise. However, our data also indicates a yet to be explored disconnect between myonectin gene expression and protein content. Further, this report highlights the importance of verifying reference genes when completing gene expression analysis. We found that many commonly used reference genes varied significantly by obesity and/or exercise and would have skewed the results of this study if used to normalize gene expression data. The unstable reference genes include: beta-Actin, beta-2-microglobulin, Non-POU domain containing, octamer-binding, Peptidylprolyl isomerase H, 18S ribosomal RNA, TATA box binding protein and Transferrin receptor.

Effects of anatabine and unilateral maximal eccentric isokinetic muscle actions on serum markers of muscle damage and inflammation

The purpose of this study was to examine the effects of anatabine supplementation in conjunction with unilateral, maximal eccentric isokinetic muscle actions on serum markers of muscle damage and pro-inflammatory cytokines in humans. Seventeen men (mean ± S.D. age = 22.4 ± 3.2 yrs) participated in this double-blinded, placebo-controlled, crossover study. Participants were randomly assigned to two 10-day conditions (anatabine and placebo) separated by a 2-4 week washout period. After seven days of supplementation, blood was sampled immediately prior to PRE, immediately following POST, and 24, 48, and 72 h after 6 sets of 10 repetitions of unilateral, maximal eccentric isokinetic forearm flexion exercise. Concentrations of serum creatine kinase, lactate dehydrogenase, myoglobin, high sensitivity c-reactive protein, and TNF-α were measured. Creatine kinase, myoglobin, and lactate dehydrogenase increased (P<0.05), while high sensitivity c-reactive protein and TNF-α did not change (P>0.05) after the eccentric exercise during both conditions. Lactate dehydrogenase was higher (P<0.05) during the anatabine condition. The primary findings of this study were two-fold: (a) anatabine had no beneficial effects on traditional markers of muscle damage (creatine kinase, lactate dehydrogenase, and myoglobin) compared to placebo after the eccentric exercise protocol, and (b) the eccentric exercise protocol did not elicit increase in the pro-inflammatory cytokines (c-reactive protein and TNF-α). Future studies are needed to examine the effects of anatabine on naturally-occurring inflammation that is common with aging or obesity. Furthermore, additional research is needed to examine the relationship between muscle damage and inflammation after eccentric exercises of different modes, durations, and intensities.

Effect of acute exercise on prostate cancer cell growth

Physical activity is associated with reduced risk of several cancers, including aggressive prostate cancer. The mechanisms mediating the effects are not yet understood; among the candidates are modifications of endogenous hormone levels. Long-term exercise is known to reduce serum levels of growth stimulating hormones. In contrast, the endocrine effects of acute endurance exercise include increased levels of mitogenic factors such as GH and IGF-1. It can be speculated that the elevation of serum growth factors may be detrimental to prostate cancer progression into malignancy. The incentive of the current study is to evaluate the effect of acute exercise serum on prostate cancer cell growth. We designed an exercise intervention where 10 male individuals performed 60 minutes of bicycle exercise at increasing intensity. Serum samples were obtained before (rest serum) and after completed exercise (exercise serum). The established prostate cancer cell line LNCaP was exposed to exercise or rest serum. Exercise serum from 9 out of 10 individuals had a growth inhibitory effect on LNCaP cells. Incubation with pooled exercise serum resulted in a 31% inhibition of LNCaP growth and pre-incubation before subcutaneous injection into SCID mice caused a delay in tumor formation. Serum analyses indicated two possible candidates for the effect; increased levels of IGFBP-1 and reduced levels of EGF. In conclusion, despite the fear of possible detrimental effects of acute exercise serum on tumor cell growth, we show that even the short-term effects seem to add to the overall beneficial influence of exercise on neoplasia.

Interleukin-6: possible biological roles during exercise

Interleukin-6 (IL-6) is a multifunctional cytokine that exerts its modulatory effects on cells that express membrane bound IL-6 receptors; however, IL-6 in a complex with soluble IL-6R can bind to any cell that express glycoprotein 130 (gp130). Thus, all cell types may respond to the pro- as well as anti-inflammatory properties of IL-6. Since the first report of acute exercise-induced increase in plasma IL-6 in the early 1990s, scientists have tried to elucidate the factors that influence the magnitude of change of plasma IL-6, as well as the possible biological roles of this cytokine. Evidence suggests that exercise intensity and duration as well as the form of contraction (e.g., eccentric or concentric) and muscle damage all influence IL-6 response to acute exercise. However, data on training status and performance on plasma IL-6 concentration changes during exercise are more inconclusive, as discussed in this review. In the last decade, most of the studies have focused on IL-6 as an 'energy sensor' possibly secreted by skeletal muscle that activates glycogenolysis in the liver and lipolysis in fat tissue in order to provide muscle with the growing energy demands during exercise.

Collagen catabolism through Coll2-1 and Coll2-1NO2 and myeloperoxidase activity in marathon runners

To determine the influence of marathon on the serum levels of two markers of cartilage degradation, Coll2-1 and its nitrated form, Coll2-1NO₂, and of a marker of neutrophils activation, the myeloperoxidase (MPO).

Coll2-1, Coll2-1NO₂, total and active MPO were measured in 98 marathon runners without joint pain and with an average age of 47 years. Sera were taken at rest right before the departure and within 30 min after the marathon. The subjects were submitted to a questionnaire concerning their physical activity and their life style.

The levels of Coll2-1, Coll2-1NO₂ and active MPO were not affected by age, body mass index, sex or performance. The levels of total MPO were higher in female than in male (p < 0.05), but were not affected by the other parameters. After the marathon, Coll2-1 and Coll2-1NO₂ concentrations were slightly but systematically decreased. The total and active MPO concentrations were increased by 2 to 3-fold in comparison to the pre-marathon values (p < 0.001 for total and active MPO). The active MPO/total MPO ratio was significantly enhanced after the marathon (p < 0.001). The variation of total MPO during the marathon was negatively correlated with the training time per week (r = −0.34; p = 0.009).

The serum levels of Coll2-1 and Coll2-1NO₂ were slightly decreased by marathon, indicating that intensive running could reduce cartilage catabolism. Furthermore, Coll2-1NO₂ was not correlated with the total and active MPO indicating that Coll2-1 nitration did not result of a systemic oxidative phenomenon but reflects local changes.

Inflammatory response to strenuous muscular exercise in man

Based on the humoral and cellular changes occurring during strenuous muscular work in humans, the concept of inflammatory response to exercise (IRE) is developed. The main indices of IRE consist of signs of an acute phase response, leucocytosis and leucocyte activation, release of inflammatory mediators, tissue damage and cellular infiltrates, production of free radicals, activation of complement, and coagulation and fibrinolytic pathways. Depending on exercise intensity and duration, it seems likely that muscle and/or associated connective tissue damage, contact system activation due to shear stress on endothelium and endotoxaemia could be the triggering mechanisms of IRE. Although this phenomenon can be considered in most cases as a physiological process associated with tissue repair, exaggerated IRE could have physiopathological consequences. On the other hand, the influence of several factors such as age, sex, training, hormonal status, nutrition, anti-inflammatory drugs, and the extent to which IRE could be a potential risk for subjects undergoing intense physical training require further study.

Efeito do exercício no sistema imune: resposta, adaptação e sinalização celular

INTRODUÇÃO: Durante o último século, o homem tornou-se menos ativo fisicamente, adotando hábitos cada vez mais sedentários. Isto promoveu aumento na incidência de doenças crônicas tais como doenças cardiovasculares, diabetes do tipo 2 e síndrome metabólica. A prática de atividade física pode influenciar o estado de higidez alterando estados metabólicos e também o sistema imunológico. OBJETIVO: Revisar na literatura estudos que abordem os efeitos promovidos pelo exercício físico no desenvolvimento da resposta imunológica e suas possíveis vias de transdução de sinais. MÉTODOS: Foram consultadas as bases de dados SciELO e PubMed. RESULTADOS: A literatura disponível mostra que durante a prática de exercício, várias subpopulações de leucócitos são alteradas de acordo com a intensidade e duração da atividade desempenhada. Exercícios de intensidade moderada estimulam uma resposta pró-inflamatória, enquanto aqueles de alta intensidade tendem a promover respostas anti-inflamatórias visando diminuir os danos na musculatura esquelética. Tais alterações são vistas em células apresentadoras de antígeno (como macrófagos e células dendríticas), neutrófilos, células natural killers (NK) e em moléculas de superfície como os receptores do tipo Toll (TLR) e do complexo principal de histocompatibilidade de classe II (MHC II), além das modificações promovidas em todo o repertório de citocinas. CONCLUSÃO: O estado atual do conhecimento permite considerar que as alterações no sistema imune são dependentes dos parâmetros inerentes ao exercício e que para que todas estas alterações ocorram, algumas cascatas de sinalização celular são acionadas, dando origem a um complexo processo de fosforilação/desfosforilação que culmina em ativação de fatores de transcrição, tradução de RNAm, síntese proteica e proliferação celular.

Can a standard dose of eicosapentaenoic acid (EPA) supplementation reduce the symptoms of delayed onset of muscle soreness?

Background

Unaccustomed exercise can result in delayed onset of muscle soreness (DOMS) which can affect athletic performance. Although DOMS is a useful tool to identify muscle damage and remodelling, prolonged symptoms of DOMS may be associated with the over-training syndrome. In order to reduce the symptoms of DOMS numerous management strategies have been attempted with no significant effect on DOMS-associated cytokines surge. The present study aimed to investigate the acute and chronic effects of a 2 × 180 mg per day dose of eicosapentaenoic acid (EPA) on interleukin-6 (IL-6) mediated inflammatory response and symptoms associated with DOMS.

Methods

Seventeen healthy non-smoking females (age 20.4 ± 2.1 years, height 161.2 ± 8.3 cm and mass 61.48 ± 7.4 kg) were randomly assigned to either placebo (N = 10) or EPA (N = 7). Serum IL-6, isometric and isokinetic (concentric and eccentric) strength, and rating of perceived exertion (RPE) were recorded on four occasions: i-prior to supplementation, ii-immediately after three weeks of supplementation (basal effects), iii-48 hours following a single bout of resistance exercise (acute training response effects), and iv-48 hours following the last of a series of three bouts of resistance exercise (chronic training response effects).

Results

There was only a group difference in the degree of change in circulating IL-6 levels. In fact, relative to the first baseline, by the third bout of eccentric workout, the EPA group had 103 ± 60% increment in IL-6 levels whereas the placebo group only had 80 ± 26% incremented IL-6 levels (P = 0.020). We also describe a stable multiple linear regression model which included measures of strength and not IL-6 as predictors of RPE scale.

Conclusion

The present study suggests that in doubling the standard recommended dose of EPA, whilst this may still not be beneficial at ameliorating the symptoms of DOMS, it counter intuitively appears to enhance the cytokine response to exercise. In a context where previous in vitro work has shown EPA to decrease the effects of inflammatory cytokines, it may in fact be that the doses required in vivo is much larger than current recommended amounts. An attempt to dampen the exercise-induced cytokine flux in fact results in an over-compensatory response of this system.

Exhaustive exercise increases inflammatory response via Toll like receptor-4 and NF-κBp65 pathway in rat adipose tissue

Cytokines (IL-6, IL-10, and TNF-α) are increased after exhaustive exercise in the retroperitoneal adipose tissue (RPAT) and mesenteric adipose tissue (MEAT). An exhaustive acute exercise protocol induces inflammation in adipose tissue that lasts 6 h after the exercise has ended. It is well-established that this protocol increases circulating plasma levels of non-esterified fatty acids (NEFAs) and lipopolysaccharides (LPS), compounds that are important in stimulating signaling via toll like receptor-4 (TLR-4) in different type cells. In the present study, we investigated the regulation of TLR-4 and DNA-binding of nuclear factor-κBp65 (NF-κBp65) in different depots of adipose tissue in rats after exhaustive exercise. Rats were killed by decapitation immediately (E0 group, n=6), 2 (E2 group, n=6), and 6 h (E6 group, n=6) after the exhaustive exercise, which consisted of running on a treadmill (approximately 70% V(O2max) ) for 50 min and then running at an elevated rate that increased at 1 m/min, until exhaustion. The control group (C group, n=6) was not subjected to exercise. In RPAT, TLR-4, MYD-88, and IkBα increased in the E2 group after exercise. MYD-88 and TRAF6 remained increased in the E6 group in comparison with the control group. DNA-binding of NF-κBp65 was not altered. In MEAT, TLR-4, MYD-88, TRAF6, and DNA-binding of NF-κBp65 were increased only in the E6 group. In conclusion, we have shown that increases in pro-inflammatory cytokines in adipose tissue pads after exhaustive exercise may be mediated via TLR-4 signaling, leading to increases in NF-κBp65 binding to DNA in MEAT.

Source and kinetics of interleukin-6 in humans during exercise demonstrated by a minimally invasive model

The objective of this study was to use a novel and non-invasive model to explore whether: (1) exercise-induced increases in systemic levels of interleukin-6 (IL-6) and other cytokines can be ascribed to local production in working muscle; and (2) how acute release of retained blood from an exercised limb impacts on metabolites in the systemic circulation. On two experimental days, at least 3 weeks apart, six healthy moderately trained male subjects performed one-legged knee-extensor exercise for 2 h at 60% of their maximal workload. On one occasion venous outflow from the exercised leg was inhibited for 18 min by inflating a cuff around the thigh as proximally as possible immediately following exercise. On the control occasion venous outflow was not inhibited. Venous blood samples were collected from an arm vein at 2-min intervals after exercise. During inhibition of venous outflow from the exercised leg systemic plasma levels of IL-6 decreased within minutes to near pre-exercise levels, whereas plasma glucose levels increased to higher levels than without the cuff. After release of the cuff, systemic levels of IL-6 increased rapidly to match levels on the control occasion. On release of the cuff, plasma levels of free fatty acids (FFAs) declined more than without the cuff. In conclusion, the observed increase in systemic IL-6 plasma concentrations during exercise can be attributed to release from the working limb. Other potential sources of IL-6 outside the working limb do not contribute significantly to the increase in plasma IL-6 levels during exercise.

The response of circulating levels of the interleukin-6/interleukin-6 receptor complex to exercise in young men

The formation of an interleukin-6/IL-6 receptor (IL-6/IL-6R) complex increases the biological activity and half-life of IL-6, with its response to exercise currently unknown. The aim of the present study was to determine the response of circulating levels of the IL-6/IL-6R complex to exercise. Nine healthy male participants performed 1h of cycling exercise at a workload required to elicit 90% lactate threshold. Venous blood samples were taken at rest, immediately post-exercise and after 1.5 h rest. Hemoglobin concentration and hematocrit were measured to estimate changes in plasma volume during exercise. The concentrations of IL-6, sIL-6R and the IL-6/IL-6R complex were measured via ELISA and corrected for changes in plasma volume. A single bout of acute exercise resulted in a 5-fold increase (P<0.05) in IL-6 and a 1.2-fold increase (P<0.05) in sIL-6R immediately after exercise. These returned to baseline at 1.5 h after the cessation of exercise. There was a 2.1-fold increase (P<0.05) in the levels of the IL-6/IL-6R complex post-exercise with levels remaining 1.8 times elevated (P<0.05) after 1.5 h rest. The present study has demonstrated, for the first time, that circulating levels of the IL-6/IL-6R complex are increased in response to acute exercise in young males.

Contractile C2C12 myotube model for studying exercise-inducible responses in skeletal muscle

Adequate exercise leads to a vast variety of physiological changes in skeletal muscle as well as other tissues/organs and is also responsible for maintaining healthy muscle displaying enhanced insulin-responsive glucose uptake via GLUT4 translocation. We generated highly developed contractile C(2)C(12) myotubes by manipulating intracellular Ca(2+) transients with electric pulse stimulation (EPS) that is endowed with properties similar to those of in vivo skeletal muscle in terms of 1) excitation-induced contractile activity as a result of de novo sarcomere formation, 2) activation of both the AMP kinase and stress-activated MAP kinase cascades, and 3) improved insulin responsiveness as assessed by GLUT4 recycling. Tbc1d1, a Rab-GAP implicated in exercise-induced GLUT4 translocation in skeletal muscle, also appeared to be phosphorylated on Ser(231) after EPS-induced contraction. In addition, a switch in myosin heavy-chain (MHC) expression from "fast type" to "slow type" was observed in the C(2)C(12) myotubes endowed with EPS-induced repetitive contractility. Taking advantage of these highly developed contractile C(2)C(12) myotubes, we identified myotube-derived factors responsive to EPS-evoked contraction, including the CXC chemokines CXCL1/KC and CXCL5/LIX, as well as IL-6, previously reported to be upregulated in contracting muscles in vivo. Importantly, animal treadmill experiments revealed that exercise significantly increased systemic levels of CXCL1/KC, perhaps derived from contracting muscle. Taken together, these results confirm that we have established a specialized muscle cell culture model allowing contraction-inducible cellular responses to be explored. Utilizing this model, we identified contraction-inducible myokines potentially linked to the metabolic alterations, immune responses, and angiogenesis induced by exercise.

Drosophila ATF-2 regulates sleep and locomotor activity in pacemaker neurons

Stress-activated protein kinases such as p38 regulate the activity of transcription factor ATF-2. However, the physiological role of ATF-2, especially in the brain, is unknown. Here, we found that Drosophila melanogaster ATF-2 (dATF-2) is expressed in large ventral lateral neurons (l-LN(v)s) and also, to a much lesser extent, in small ventral lateral neurons, the pacemaker neurons. Only l-LN(v)s were stained with the antibody that specifically recognizes phosphorylated dATF-2, suggesting that dATF-2 is activated specifically in l-LN(v)s. The knockdown of dATF-2 in pacemaker neurons using RNA interference decreased sleep time, whereas the ectopic expression of dATF-2 increased sleep time. dATF-2 knockdown decreased the length of sleep bouts but not the number of bouts. The ATF-2 level also affected the sleep rebound after sleep deprivation and the arousal threshold. dATF-2 negatively regulated locomotor activity, although it did not affect the circadian locomotor rhythm. The degree of dATF-2 phosphorylation was greater in the morning than at night and was enhanced by forced locomotion via the dp38 pathway. Thus, dATF-2 is activated by the locomotor while it increases sleep, suggesting a role for dATF-2 as a regulator to connect sleep with locomotion.

Response of plasma IL-6 and its soluble receptors during submaximal exercise to fatigue in sedentary middle-aged men

The pleiotropic cytokine interleukin-6 (IL-6) has been demonstrated to increase during exercise. Little is known regarding the response of the soluble IL-6 receptors (sIL-6R and sgp130) during such exercise. The aim of the current study was to investigate the response of plasma IL-6, sIL-6R and sgp130 during fatiguing submaximal exercise in humans. Twelve participants underwent an incremental exercise test to exhaustion and one week later performed a submaximal exercise bout (96 +/- 6% lactate threshold) to volitional exhaustion. Blood samples taken at rest and immediately post exercise were analyzed for IL-6, sIL-6R and sgp130. IL-6 increased (P < 0.01) by 8.4 +/- 8.9 pg ml(-1) (75.7%) during the exercise period. sIL-6R and sgp130 also increased (P < 0.05) by 2.7 +/- 3.9 ng ml(-1) (9.6%) and 37.7 +/- 55.6 ng ml(-1) (9.6%), respectively. The current study is the first investigation to demonstrate that alongside IL-6, acute exercise stress results in an increase in both sIL-6R and sgp130.