The role of exercise-induced myokines in muscle homeostasis and the defense against chronic diseases

Impact of aerobic exercise on levels of IL-4 and IL-10: results from two randomized intervention trials

The mechanisms whereby regular exercise reduces chronic inflammation remain unclear. We investigated whether regular aerobic exercise alters basal levels of interleukin (IL)‐10 and IL‐4 in two randomized trials of physical activity. The Alberta Physical Activity and Breast Cancer Prevention Trial (ALPHA, n = 320) and the Breast Cancer and Exercise Trial in Alberta (BETA, n = 400) were two‐center, two‐armed randomized trials in inactive, healthy, postmenopausal women. Both trials included an exercise intervention prescribed five times/week and no dietary changes. In ALPHA, the exercise group was prescribed 225 min/week versus no activity in the controls. BETA examined dose‐response effects comparing 300 (HIGH) versus 150 (MODERATE) min/week. Plasma concentrations of IL‐10 and IL‐4 were measured at baseline, 6, and 12 months. Intention‐to‐treat (ITT) analysis was performed using linear mixed models adjusted for baseline biomarker concentrations. Circulating anti‐inflammatory cytokine levels decreased among all groups, with percent change ranging from −3.4% (controls) to −8.2% (HIGH) for IL‐4 and −1.6% (controls) to −7.5% (HIGH) for IL‐10. No significant group differences were found for IL‐4 (ALPHA P = 0.54; BETA P = 0.32) or IL‐10 (ALPHA P = 0.84; BETA P = 0.68). Some evidence for moderation of the effect of exercise by baseline characteristics was found for IL‐10 but not for IL‐4. Results from these two large randomized aerobic exercise intervention trials suggest that aerobic exercise does not alter IL‐10 or IL‐4 in a manner consistent with chronic disease and cancer prevention.

Habitual physical activity is associated with the maintenance of neutrophil migratory dynamics in healthy older adults

BACKGROUND

Dysfunctional neutrophils with advanced age are a hallmark of immunosenescence. Reduced migration and bactericidal activity increase the risk of infection. It remains unclear why neutrophil dysfunction occurs with age. Physical activity and structured exercise have been suggested to improve immune function in the elderly. The aim of this study was to assess a comprehensive range of neutrophil functions and determine their association with habitual physical activity.

METHOD

Physical activity levels were determined in 211 elderly (67±5years) individuals by 7-days of accelerometry wear. Twenty of the most physically active men and women were matched for age and gender to twenty of the least physically active individuals. Groups were compared for neutrophil migration, phagocytosis, oxidative burst, cell surface receptor expression, metabolic health parameters and systemic inflammation. Groups were also compared against ten young participants (23±4years).

RESULTS

The most active group completed over twice as many steps/day as the least active group (p<0.001), had lower BMI's (p=0.007) and body fat percentages (p=0.029). Neutrophils migrated towards IL-8 better in the most active group compared to the least active (p<0.05) and was comparable to that of the young (p>0.05). These differences remained after adjusting for BMI, body fat and plasma metabolic markers which were different between groups. Correlations revealed that steps/day, higher adiponectin and lower insulin were positively associated with migratory ability (p<0.05). There was no difference in expression of the chemokine receptors CXCR1 or CXCR2 (p>0.05 for both). CD11b was higher in the most active group compared to the least active (p=0.048). No differences between activity groups or young controls were observed for neutrophil phagocytosis or oxidative burst in response to Escherichia coli (p>0.05). The young group had lower concentrations of IL-6, IL-8, MCP-1, CRP, IL-10 and IL-13 (p<0.05 for all) with no differences between the two older groups.

CONCLUSION

These data suggest that impaired neutrophil migration, but not bactericidal function, in older adults may be, in part, the result of reduced physical activity. A 2-fold difference in physical activity is associated with better preserved neutrophil migratory dynamics in healthy older people. As a consequence increasing habitual physical activity may be beneficial for neutrophil mediated immunity.

Weight loss improves biomarkers endothelial function and systemic inflammation in obese postmenopausal Saudi women

BACKGROUND

Although postmenopausal associated disorders are important public health problems worldwide, to date limited studies evaluated the endothelial function and systemic inflammation response to weight loss in obese postmenopausal women.

OBJECTIVE

This study was done to evaluate the endothelial function and systemic inflammation response to weight loss in obese postmenopausal Saudi women.

MATERIAL AND METHODS

Eighty postmenopausal obese Saudi women (mean age 52.64±6.13 year) participated in two groups: Group (A) received aerobic exercise on treadmill and diet whereas, group (B) received no intervention. Markers of inflammation and endothelial function were measured before and after 3 months at the end of the study.

RESULTS

The values of body mass index(BMI), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), inter-cellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1) and plasminogen activator inhibitor-1 activity (PAI-1:Ac) were significantly decreased in group (A), while changes were not significant in group (B). Also, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) after treatment.

CONCLUSION

Weight loss ameliorates inflammatory cytokines and markers of endothelial function in obese postmenopausal Saudi women.

Cytokine Signaling in Skeletal Muscle Wasting

Skeletal muscle wasting occurs in a variety of diseases including diabetes, cancer, Crohn's disease, chronic obstructive pulmonary disease (COPD), disuse, and denervation. Tumor necrosis factor α (TNF-α) is involved in mediating the wasting effect. To date, a causal relationship between TNF-α signaling and muscle wasting has been established in animal models. However, results from clinical trials are conflicting. This is partly due to the fact that other factors such as TNF-like weak inducer of apoptosis (TWEAK) and interleukin 6 (IL-6) are also involved in skeletal muscle wasting. Because muscle wasting is often associated with physical inactivity and reduced food intake, therapeutic interventions will be most effective when multiple approaches are used in conjunction with nutritional support and exercise.

The correlation of resistance exercise-induced myostatin with insulin resistance and plasma cytokines in healthy young men

PURPOSE

This study was designed to examine the correlation of resistance exercise (RE)-induced myostatin (MSTN) with insulin resistance and plasma cytokines in healthy young men.

METHODS

Twenty-four healthy men were randomly divided into RE (n = 12) and control (n = 12) group. After a session of familiarization, one repetition maximum (1-RM) was calculated. Circuit RE program involved 3 sets of 15 repetitions at 55 % of 1-RM. Blood samples were collected before and 24 h after the exercise. Paired t test, independent t test, and Pearson's correlation were used for analyzing data.

RESULTS

A significant decrease in plasma level of MSTN, glucose, insulin, interleukin-6 (IL-6), and homeostasis model assessment of insulin resistance (HOMA-IR) and a significant increase in plasma interleukin-10 (IL-10) were found in RE group 24 h post-exercise versus pre-exercise (p < 0.05). Furthermore, except plasma IL-10, a significant decrease in metabolic variables was found in RE group versus control group (p < 0.05). A significantly positive correlation of plasma MSTN with HOMA-IR and plasma IL-6 and a significantly negative correlation of plasma MSTN with plasma IL-10 were found in RE group versus control group (p < 0.05).

CONCLUSIONS

It seems that a circuit RE bout by reducing HOMA-IR and changing plasma cytokines (decreased IL-6 and increased IL-10) can decrease plasma level of MSTN in healthy young men. In other word, the beneficial effect of acute RE may be reflected by changes in MSTN in healthy young individuals.

Moderate-intensity exercise reduces fatigue and improves mobility in cancer survivors: a systematic review and meta-regression

QUESTION

Is there a dose-response effect of exercise on inflammation, fatigue and activity in cancer survivors?

DESIGN

Systematic review with meta-regression analysis of randomised trials.

PARTICIPANTS

Adults diagnosed with cancer, regardless of specific diagnosis or treatment.

INTERVENTION

Exercise interventions including aerobic and/or resistance as a key component.

OUTCOME MEASURES

The primary outcome measures were markers of inflammation (including C-reactive protein and interleukins) and various measures of fatigue. The secondary outcomes were: measures of activity, as defined by the World Health Organization's International Classification of Functioning, Disability and Health, including activities of daily living and measures of functional mobility (eg, 6-minute walk test, timed sit-to-stand and stair-climb tests). Risk of bias was evaluated using the PEDro scale, and overall quality of evidence was assessed using the Grades of Research, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Forty-two trials involving 3816 participants were included. There was very low-quality to moderate-quality evidence that exercise results in significant reductions in fatigue (SMD 0.32, 95% CI 0.13 to 0.52) and increased walking endurance (SMD 0.77, 95% CI 0.26 to 1.28). A significant negative association was found between aerobic exercise intensity and fatigue reduction. A peak effect was found for moderate-intensity aerobic exercise for improving walking endurance. No dose-response relationship was found between exercise and markers of inflammation or exercise duration and outcomes. Rates of adherence were typically high and few adverse events were reported.

CONCLUSIONS

Exercise is safe, reduces fatigue and increases endurance in cancer survivors. The results support the recommendation of prescribing moderate-intensity aerobic exercise to reduce fatigue and improve activity in people with cancer.

REVIEW REGISTRATION

PROSPERO CRD42015019164.

Handgrip Strength Cutoff Points to Identify Mobility Limitation in Community-dwelling Older People and Associated Factors

BACKGROUND

Sarcopenia is defined as a progressive and generalized loss of skeletal muscle mass and strength. The specific threshold of muscle weakness that leads to mobility limitations has not been identified.

OBJECTIVES

To determine the best cutoff point of handgrip strength for identifying mobility limitation and to investigate the factors associated with muscle weakness and mobility limitation in community-dwelling older people.

DESIGN

Transversal study.

SETTING

Cities of Belo Horizonte, Barueri and Santa Cruz in Brazil.

PARTICIPANTS

1374 community-dwelling older people from the Frailty study in Brazilian older people (FIBRA Study).

MEASUREMENTS

Outcomes included muscle weakness determined according to gender-specific handgrip strength cutoff points generated by Receiver Operating Characteristic curves, mobility limitation defined as a gait speed ≤ 0.8 m/s; and a combination of both muscle weakness and mobility limitation. Associated factors included socio-demographic variables, lifestyle, anthropometrics, health conditions, use of health services and disability.

RESULTS

The cutoff points of handgrip strength with the best balancing between sensitivity and specificity for mobility limitation were 25.8 kgf for men (sensitivity 69%, specificity 73%) and 17.4 kgf (sensitivity 60%, specificity 66%) for women. Age and disability in instrumental activities of daily living were associated with all outcomes. Women had greater odds of mobility limitation than men. Physical inactivity, body fat, diabetes, depression, sleeping disturbances, number of medications and occurrence of falls remained as significant associated factors in the final model.

CONCLUSIONS

Handgrip strength can be a useful tool to identify mobility limitation in clinical practice. Interventions to prevent or minimize impacts of sarcopenia should stimulate physical activity and improvement of body composition in addition to the management of chronic diseases and disabilities.

Determinants of change in physical activity during moderate-to-severe COPD exacerbation

BACKGROUND

Data are scarce on patient physical activity (PA) level during exacerbations of chronic obstructive pulmonary disease (eCOPD). The objective of the study was to evaluate the level and determinants of change in PA during an eCOPD.

MATERIALS AND METHODS

We conducted a prospective cohort study with recruitment from emergency departments (EDs) of 16 participating hospitals from June 2008 to September 2010. Data were recorded on socioeconomic characteristics, dyspnea, forced expiratory volume in 1 second (FEV1%), comorbidities, health-related quality of life, factors related to exacerbation, and PA in a stable clinical condition and during the eCOPD episode.

RESULTS

We evaluated 2,487 patients. Common factors related to the change in PA during hospital admission or 7 days after discharge to home from the ED were lower PA at baseline and during the first 24 hours after the index evaluation. Age, quality of life, living alone, length of hospital stay, and use of anticholinergic or systemic corticosteroids in treating the exacerbation were associated with the change in PA among hospitalized patients. Predictors of change among patients not admitted to hospital were baseline FEV1% and dyspnea at rest on ED arrival.

CONCLUSION

Among the patients evaluated in an ED for an eCOPD, the level and change in PA was markedly variable. Factors associated with exacerbation (PA 24 hours after admission, medication during admission, and length of hospital stay) and variables reflecting patients' stable clinical condition (low level of PA, age, quality of life, FEV1%) are predictors of the change in PA during a moderate-to-severe eCOPD.

Wet, volatile, and dry biomarkers of exercise-induced muscle fatigue

Background

The physiological background of exercise-induced muscle fatigue(EIMUF) is only poorly understood. Thus, monitoring of EIMUF by a single or multiple biomarkers(BMs) is under debate.

After a systematic literature review 91 papers were included.

Results

EIMUF is mainly due to depletion of substrates, increased oxidative stress, muscle membrane depolarisation following potassium depletion, muscle hyperthermia, muscle damage, impaired oxygen supply to the muscle, activation of an inflammatory response, or impaired calcium-handling. Dehydration, hyperammonemia, mitochondrial biogenesis, and genetic responses are also discussed. Since EIMUF is dependent on age, sex, degree of fatigue, type, intensity, and duration of exercise, energy supply during exercise, climate, training status (physical fitness), and health status, BMs currently available for monitoring EIMUF have limited reliability. Generally, wet, volatile, and dry BMs are differentiated. Among dry BMs of EIMUF the most promising include power output measures, electrophysiological measures, cardiologic measures, and questionnaires. Among wet BMs of EIMUF those most applicable include markers of ATP-metabolism, of oxidative stress, muscle damage, and inflammation. VO₂-kinetics are used as a volatile BM.

Conclusions

Though the physiology of EIMUF remains to be fully elucidated, some promising BMs have been recently introduced, which together with other BMs, could be useful in monitoring EIMUF. The combination of biomarkers seems to be more efficient than a single biomarker to monitor EIMUF. However, it is essential that efficacy, reliability, and applicability of each BM candidate is validated in appropriate studies.

1α,25(OH)2D3 downregulates gene expression levels of muscle ubiquitin ligases MAFbx and MuRF1 in human myotubes

Clinical trials involving in patients with osteoporosis have reported that activated vitamin D3 (1α,25(OH)2D3, calcitriol) can prevent falling by acting on the skeletal muscles. However, pharmacological mechanisms of 1α,25(OH)2D3 with respect to skeletal muscle hypertrophy or atrophy are still poorly understood. Therefore, we examined changes in the expression of several related genes in human myotubes to test whether 1α,25(OH)2D3 influences hypertrophy and atrophy of skeletal muscle. Myotubes treated with 1α,25(OH)2D3 increased interleukin-6 (IL-6) expression and inhibited expression of tumor necrosis factor alpha (TNF-α), whereas the expression of insulin-like growth factor-1 (IGF-1) that is involved in muscle hypertrophy was not affected. However, 1α,25(OH)2D3 treatment significantly inhibited the expression of muscle atrophy F-box (MAFbx) and muscle RING finger 1 (MuRF1), ubiquitin ligases involved in muscle atrophy. The analysis of pathways using microarray data suggested that 1α,25(OH)2D3 upregulates AKT-1 by inhibiting the expression of protein phosphatase 2 (PP2A), a phosphatase acting on AKT-1, in the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, thereby inhibiting the expression of ubiquitin ligases. Thus, this study showed that 1α,25(OH)2D3 might have an inhibitory effect on the expression of MAFbx and MuRF1 in skeletal muscle and a suppressive effect on muscle degradation in patients with osteoporosis.

Nutrition and Physical Activity in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and it is associated with other medical conditions such as diabetes mellitus, metabolic syndrome, and obesity. The mechanisms of the underlying disease development and progression are not completely established and there is no consensus concerning the pharmacological treatment. In the gold standard treatment for NAFLD weight loss, dietary therapy, and physical activity are included. However, little scientific evidence is available on diet and/or physical activity and NAFLD specifically. Many dietary approaches such as Mediterranean and DASH diet are used for treatment of other cardiometabolic risk factors such as insulin resistance and type-2 diabetes mellitus (T2DM), but on the basis of its components their role in NAFLD has been discussed. In this review, the implications of current dietary and exercise approaches, including Brazilian and other guidelines, are discussed, with a focus on determining the optimal nonpharmacological treatment to prescribe for NAFLD.

Perilipin 5-Driven Lipid Droplet Accumulation in Skeletal Muscle Stimulates the Expression of Fibroblast Growth Factor 21

Perilipin 5 (PLIN5) is a lipid droplet protein and is highly expressed in oxidative tissue. Expression of the PLIN5 gene is regulated by peroxisome proliferator-activated receptor-α, fasting, and exercise. However, the effect of increased muscle PLIN5 expression on whole-body energy homeostasis remains unclear. To examine this, we developed a mouse line with skeletal muscle PLIN5 overexpression (MCK-Plin5). We show that MCK-Plin5 mice have increased energy metabolism and accumulate more intramyocellular triacylglycerol but have normal glucose and insulin tolerance. MCK-Plin5 mice fed high-fat chow manifest lower expression of inflammatory markers in their liver and increased expression of "browning" factors in adipose tissue. This muscle-driven phenotype is, at least in part, mediated by myokines; the MCK-Plin5 mice have 80-fold higher FGF21 gene expression in muscle and increased serum FGF21 concentration. The increase in FGF21 occurs mainly in muscles with a predominance of fast-twitch fibers, suggesting that fiber type-specific lipid storage may be part of the mechanism conferring metabolic protection in MCK-Plin5 mice. In conclusion, upregulating the PLIN5 level in skeletal muscle drives expression of the FGF21 gene in fast-twitch fibers and is metabolically protective. These findings provide insight into the physiology of PLIN5 and the potential contribution of its upregulation during exercise.

Effects of combined aerobic and resistance training on the glycolipid metabolism and inflammation levels in type 2 diabetes mellitus

[Purpose] To investigate the effects of combined aerobic and resistance training on glycolipid metabolism and inflammation levels in type 2 diabetes mellitus patients. [Subjects and Methods] Forty-two diabetes patients were randomized to the conventional therapy group (n = 20) or intensive therapy group (n = 22). The control group contained 20 healthy people. The conventional therapy group received routine drug therapy and diet control, while the intensive therapy group additionally underwent combined aerobic and resistance training for 12 weeks. The oral glucose tolerance test and cardiopulmonary exercise testing were performed. Toll-like receptor 4 and NF-κBp65 protein and mRNA expressions were determined by qPCR and western blotting. ELISA was used to determine the expression levels of interleukin-18, interleukin-33, pentraxin-related protein 3, and human cartilage glycoprotein 39. [Results] After exercise training, the intensive therapy group had significantly lower postprandial blood glucose, postprandial insulin, and glycated hemoglobin level and insulin resistance index than the conventional therapy group. The intensive therapy group had significantly lower toll-like receptor 4 and NF-κBp65 protein and mRNA expressions, and serum interleukin-18 levels but significantly higher serum interleukin-33 levels. [Conclusion] Combined aerobic and resistance training can improve glycolipid metabolism and reduce low-grade inflammation in patients with diabetes mellitus patients.

Exercise attenuates inflammation and limits scar thinning after myocardial infarction in mice

Although exercise mediates beneficial effects in patients after myocardial infarction (MI), the underlying mechanisms as well as the question of whether an early start of exercise after MI is safe or even beneficial are incompletely resolved. The present study analyzed the effects of exercise before and reinitiated early after MI on cardiac remodeling and function. Male C57BL/6N mice were housed sedentary or with the opportunity to voluntarily exercise for 6 wk before MI induction (ligation of the left anterior descending coronary artery) or sham operation. After a 5-day exercise-free phase after MI, mice were allowed to reexercise for another 4 wk. Exercise before MI induced adaptive hypertrophy with moderate increases in heart weight, cardiomyocyte diameter, and left ventricular (LV) end-diastolic volume, but without fibrosis. In sedentary mice, MI induced eccentric LV hypertrophy with massive fibrosis but maintained systolic LV function. While in exercised mice gross LV end-diastolic volumes and systolic function did not differ from sedentary mice after MI, LV collagen content and thinning of the infarcted area were reduced. This was associated with ameliorated activation of inflammation, mediated by TNF-α, IL-1β, and IL-6, as well as reduced activation of matrix metalloproteinase 9. In contrast, no differences in the activation patterns of various MAPKs or adenosine receptor expressions were observed 5 wk after MI in sedentary or exercised mice. In conclusion, continuous exercise training before and with an early reonset after MI ameliorates adverse LV remodeling by attenuating inflammation, fibrosis, and scar thinning. Therefore, an early reonset of exercise after MI can be encouraged.

Physical Activity Protects the Human Brain against Metabolic Stress Induced by a Postprandial and Chronic Inflammation

In recent years, it has become clear that chronic systemic low-grade inflammation is at the root of many, if not all, typically Western diseases associated with the metabolic syndrome. While much focus has been given to sedentary lifestyle as a cause of chronic inflammation, it is less often appreciated that chronic inflammation may also promote a sedentary lifestyle, which in turn causes chronic inflammation. Given that even minor increases in chronic inflammation reduce brain volume in otherwise healthy individuals, the bidirectional relationship between inflammation and sedentary behaviour may explain why humans have lost brain volume in the last 30,000 years and also intelligence in the last 30 years. We review evidence that lack of physical activity induces chronic low-grade inflammation and, consequently, an energy conflict between the selfish immune system and the selfish brain. Although the notion that increased physical activity would improve health in the modern world is widespread, here we provide a novel perspective on this truism by providing evidence that recovery of normal human behaviour, such as spontaneous physical activity, would calm proinflammatory activity, thereby allocating more energy to the brain and other organs, and by doing so would improve human health.

Juvenile idiopathic arthritis and physical activity: possible inflammatory and immune modulation and tracks for interventions in young populations

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease characterized by persistent joint inflammation that manifests as joint pain and swelling and limited range of joint motion. In healthy subjects, the literature reports that physical activity has an anti-inflammatory effect. In JIA patients, exercise could be used as a therapeutic tool to counteract disease-related inflammation and thereby improve clinical symptoms, although transient flare of pain could be the price to pay. Indeed, in patients with a chronic inflammatory disease, physical activity is prone to exacerbate underlying inflammatory stress. Physical activity improves quality of life and symptoms in JIA patients, but the mechanisms of action remain unclear. This review focuses on the mechanisms underlying exercise-induced immune and hormonal changes. Data on the impact of acute and chronic physical activities on the secretion of hormones and other molecules such as miRNA or peptides involved in the inflammatory process in JIA was compiled and summarized, and the key role of the biological effect of muscle-derived interleukin 6 in the exercise-induced modulation of pro/anti-inflammatory balance is addressed. We also go on to review the effect of training and type of exercise on cytokine response. This review highlights the beneficial effect of physical exercise in children with JIA and potential effect of exercise on the balance between pro- and anti-inflammatory response.

Tumor necrosis factor-alpha is a potential diagnostic biomarker for chronic neuropathic pain after spinal cord injury

Neuropathic pain (NP) is one of the most common complications after spinal cord injury (SCI), but no protein biomarkers has ever been introduced into clinical diagnosis. Previous studies implicated that toll-like receptor (TLR) 4 played a critical role in the development of NP in animal SCI models. Here, a total of 140 participants were recruited, 70 of them were SCI-NP subject and the rest 70 controls did not show neuropathic symptoms. TLR4 was upregulated significantly in SCI-NP patients compared with SCI-noNP subjects. Furthermore, we measured the concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), two TLR4 downstream pro-inflammatory cytokines, to assess their diagnostic values. Receiver operating characteristics (ROC) analysis revealed that TNF-α had great potential advantages to predict the progression of neuropathy, the risks of NP were strongly increased in SCI subjects with higher levels of TNF-α (odds ratio: 4.92; 95% confidence interval: 1.89-12.32). These results suggested neuro-immune activation contributed to the development of neuropathic disorder after SCI, and TNF-α could be a potential sensitive diagnostic biomarker for chronic neuropathic pain in SCI patients.

Acute pro- and anti-inflammatory responses to resistance exercise in patients with coronary artery disease: a pilot study

Little is known about the inflammatory effects of resistance exercise in healthy and even less in diseased individuals such as cardiac patients. The purpose of this study was to examine the acute pro- and anti-inflammatory responses during resistance exercise (RE) in patients with coronary artery disease. Eight low risk patients completed two acute RE protocols at low (50% of 1 RM; 2x18 rps) and moderate intensity (75% of 1 RM; 3x8 rps) in random order. Both protocols included six exercises and had the same total load volume. Blood samples were obtained before, immediately after and 60 minutes after each protocol for the determination of lactate, TNFα, INF-γ, IL-6, IL-10, TGF-β1, and hsCRP concentrations. IL-6 and IL-10 levels increased (p < 0.05) immediately after both RE protocols with no differences between protocols. INF-γ was significantly lower (p < 0.05) 60 min after the low intensity protocol, whereas TGF-β1 increased (p < 0.05) immediately after the low intensity protocol. There were no differences in TNF-& and hs-CRP after both RE protocols or between protocols. The above data indicate that acute resistance exercise performed at low to moderate intensity in low risk, trained CAD patients is safe and does not exacerbate the inflammation associated with their disease. Key pointsAcute resistance exercise is safe without exacerbating inflammation in patients with CAD.Both exercise intensities (50 and 75% of 1 RM) elicit desirable pro-and anti-inflammatory responses.With both exercise intensities (50 and 75% of 1 RM) acceptable clinical hemodynamic alterations were observed.

Irisin and Myonectin Regulation in the Insulin Resistant Muscle: Implications to Adipose Tissue: Muscle Crosstalk

Myokines are peptides produced and secreted by the skeletal muscle, with autocrine, paracrine, and endocrine actions. Many of them are overexpressed during physical exercise and appear to contribute to the benefits of exercise to metabolic homeostasis. Irisin, resulting from the cleavage of the membrane protein FNDC5, was shown to induce adipocyte browning, with increased lipid oxidation and thermogenesis. Myonectin was only recently discovered and initial studies revealed a role in fatty acid uptake and oxidation in adipose tissue and liver. However, the mechanisms of their regulation by exercise are not entirely established. Impaired secretion and action of myokines, such as irisin and myonectin, may have a role in the establishment of insulin resistance. On the other hand, several studies have shown that insulin resistance in the skeletal muscle may change myokines expression and secretion. This may have consequences on lipid and glucose metabolism in adipose tissue and lead to a vicious cycle between impaired myokines production and insulin resistance. This review summarizes the current knowledge about the influence of skeletal muscle insulin resistance on the secretion of irisin and myonectin, as well as its impact on adipose tissue metabolism.

Toll-like receptor 4 and tumor necrosis factor-alpha as diagnostic biomarkers for diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes, but currently no protein biomarkers have been introduced into clinical diagnosis, especially among early-stage diabetic patients. Our previous study in animal model showed Toll-like receptor (TLR) 4 and its downstream signaling molecules were associated with DPN. To assess the diagnostic values of TLR4, TNF-α, and IL-6 as biomarkers, here we detected their expressions in peripheral blood from normal controls, type 2 diabetic and DPN subjects. Both TLR4 mRNA and protein expressions increased significantly in DPN compare with both diabetic and control subjects. The protein levels of TNF-α and IL-6 were also raised significantly and correlated with TLR4 expression. Receiver operating characteristics (ROC) analysis suggested TLR4 and TNF-α had great potential advantages to predict the progression of neuropathy, the risks of DPN were increased in subjects with higher TLR4 (odds ratio: 5.27; 95% CI: 1.02-26.40) and TNF-α (odds ratio: 12.67; 95% CI: 2.35-68.22). These findings demonstrated TLR4 and TNF-α could be potential sensitive diagnostic biomarkers for DPN in both general population and type 2 diabetic subjects.

Synergistic effect of interleukin-6 and hyaluronic acid on cell migration and ERK activation in human keratinocytes

Wound healing is initiated and progressed by complex integrated process of cellular, physiologic, and biochemical events, such as inflammation, cell migration and proliferation. Interleukin 6 (IL-6) is a multifunctional cytokine, and it could regulate the inflammatory response of wound healing process in a timely manner. Hyaluronic acid (HA) is an essential component of the extracellular matrix, and contributes significantly to cell proliferation and migration. The purpose of this study was to investigate the effects of IL-6 or/and HA on the cell migration process in human keratinocytes. Combining IL-6 and HA significantly increased the cell migration in scratch based wound healing assay. The phosphorylation of extracellular-signal-regulated kinase (ERK) was significantly increased after 1 hr of IL-6 and HA treatment, but the phosphorylation of p38 mitogen-activated protein kinase (MAPK) was not. We also found that significant increase of the NF-κB translocation from cytoplasm into nucleus after 1 hr of IL-6 or/and HA treatments. This study firstly showed that synergistic effects of combining IL-6 and HA on the cell migration of wound healing by activation of ERK and NF-κB signaling. Further studies might be required to confirm the synergistic effects of HA and IL-6 in the animal model for the development of a novel therapeutic mixture for stimulation of wound healing process.

The fatty acid amide hydrolase in lymphocytes from sedentary and active subjects

PURPOSE

Endocannabinoids (eCB) and interleukin 6 (IL-6) levels change during physical activity, thus suggesting their involvement in the modulation of exercise-related processes like inflammation and energy homeostasis. To investigate whether lifestyle might affect the activity of the eCB-degrading enzyme fatty acid amide hydrolase (FAAH), active and sedentary subjects were enrolled.

METHODS

Plasma IL-6 levels and lymphocyte FAAH activity of eight physically active male subjects (mean ± SEM; age = 39.3 ± 2.9 yr, body mass index = 21.1 ± 0.4 kg·m), usually practicing aerobic exercise (8.1 ± 1.2 h·wk), and eight sedentary subjects (38.8 ± 3.7 yr, body mass index = 23.1 ± 0.8 kg·m) were measured. Also, in vitro effect of IL-6 was tested on FAAH expression and activity and on FAAH promoter activity in lymphocytes from sedentary subjects.

RESULTS

Under resting conditions (at least 12 h from the last exercise), the active group showed plasma IL-6 levels (2.74 ± 0.73 pg·mL) and lymphocyte FAAH activity (215.7 ± 38.5 pmol·min·mg protein) significantly higher than those measured in the sedentary group (0.20 ± 0.02 pg·mL, and 42.0 ± 4.2 pmol·min·mg protein). Increased IL-6 levels paralleled increased FAAH activity, and consistently, the in vitro treatment of lymphocytes from sedentary individuals with 10 ng·mL IL-6 for 48 h significantly increased FAAH expression and activity. Transient transfection experiments showed that IL-6 induced the expression of a reporter gene under the control of a cAMP response element-like region in the human FAAH promoter. A mutation in the same element abolished IL-6 up-regulation, demonstrating that this cytokine regulates FAAH activity at the transcriptional level.

CONCLUSION

IL-6 leads to activation of the FAAH promoter, thus enhancing FAAH activity that modulates the eCB tone in physically active people.

Bedside ultrasound measurement of skeletal muscle

PURPOSE OF REVIEW

Skeletal muscle and lean body mass may be vital to prognosis and functional recovery in chronic and acute illness, particularly in conditions in which muscle atrophy is prevalent. Ultrasound provides a precise and expedient method to measure muscle mass and changes in skeletal muscle at the bedside.

RECENT FINDINGS

Here, we describe the various methodological approaches along with the validation and reliability tests that have been performed in various populations. Current applications of ultrasound in chronic and acute illness as well as its limitations and strengths in quantifying the muscle mass and changes in muscle over time are discussed. To capitalize on the beneficial features of ultrasound for measuring muscle, we describe the work that is needed to optimize the usefulness of ultrasound in chronic disease and acute care.

SUMMARY

Given the precision, practicality, and ease of use, ultrasound is emerging as a highly useful tool in expediently measuring the muscle mass and changes in muscle tissue at the bedside. Ultrasound may be valuable in identifying patients who are at risk of malnutrition, in tracking muscle atrophy for the purpose of calculating nutrient delivery, and in assessing the success or failure of nutrition, pharmacological and rehabilitative interventions that aim to counter muscle atrophy.

Role of exercise training on autonomic changes and inflammatory profile induced by myocardial infarction

The cardiovascular autonomic imbalance in patients after myocardial infarction (MI) provides a significant increase in mortality rate, and seems to precede metabolic, hormonal, and immunological changes. Moreover, the reduction in the parasympathetic function has been associated with inflammatory response in different pathological conditions. Over the years, most of the studies have indicated the exercise training (ET) as an important nonpharmacological tool in the management of autonomic dysfunction and reduction in inflammatory profile after a myocardial infarction. In this work, we reviewed the effects of ET on autonomic imbalance after MI, and its consequences, particularly, in the post-MI inflammatory profile. Clinical and experimental evidence regarding relationship between alterations in autonomic regulation and local or systemic inflammation response after MI were also discussed.

Exercise benefits in chronic graft versus host disease: a murine model study

INTRODUCTION

Chronic graft versus host disease (cGVHD) is a life-threatening complication of allogeneic hematopoietic stem cell transplantation that generates considerable morbidity and compromises the physical capacity of patients. We determined the effects of an exercise training program performed after allogeneic hematopoietic stem cell transplantation on clinical and biological variables in a minor histocompatibility antigen-driven murine model of cGVHD treated with cyclosporine A.

METHODS

Recipient BALB/C female mice (age 8 wk) received bone marrow cells and splenocytes from donor B10.D2 male mice and were randomly assigned to an exercise (n = 11) or control group (n = 12). For approximately 11 wk after transplant, the exercise group completed a moderate-intensity treadmill program. Variables assessed were clinical severity scores, survival, physical fitness, cytokine profile, immune cell reconstitution, molecular markers of muscle exercise adaptations, and histological scores in affected tissues.

RESULTS

Exercise training increased survival (P = 0.011), diminished total clinical severity scores (P = 0.002), improved physical fitness (P = 0.030), and reduced blood IL-4 and tumor necrosis factor α levels (P = 0.03), while increasing circulating B220 (P = 0.008) and CD4 lymphocytes (P = 0.043).

CONCLUSIONS

A moderate-intensity exercise program that mimics widely accepted public health recommendations for physical activity in human adults was well tolerated and positive effects on survival as well as on clinical and biological indicators of cGVHD.

Benefits of exercise intervention in reducing neuropathic pain

Peripheral neuropathy is a widespread and potentially incapacitating pathological condition that encompasses more than 100 different forms and manifestations of nerve damage. The diverse pathogenesis of peripheral neuropathy affects autonomic, motor and/or sensory neurons, and the symptoms that typify the condition are abnormal cutaneous sensation, muscle dysfunction and, most notably, chronic pain. Chronic neuropathic pain is difficult to treat and is often characterized by either exaggerated responses to painful stimuli (hyperalgesia) or pain resulting from stimuli that would not normally provoke pain (allodynia). The objective of this review is to provide an overview of some pathways associated with the development of peripheral neuropathy and then discuss the benefits of exercise interventions. The development of neuropathic pain is a highly complex and multifactorial process, but recent evidence indicates that the activation of spinal glial cells via the enzyme glycogen synthase kinase 3 and increases in the production of both pro-inflammatory cytokines and brain derived neurotropic factor are crucial steps. Since many of the most common causes of peripheral neuropathy cannot be fully treated, it is critical to understand that routine exercise may not only help prevent some of those causes, but that it has also proven to be an effective means of alleviating some of the condition’s most distressing symptoms. More research is required to elucidate the typical mechanisms of injury associated with peripheral neuropathy and the exercise-induced benefits to those mechanisms.

Abdominal obesity: causal factor or simply a symptom of obesity-related health risk

BACKGROUND

Abdominal fat (AF) reduction is advocated in the treatment of obesity-related diseases. Nonetheless, recent studies have shown additional beneficial effects against obesity-related health risks, independent of AF reduction. Therefore it is important to determine whether AF plays a causal role in promoting metabolic disorders or is simply a symptom of increased obesity-related health risk factors. Clarification of the primary role of AF in the pathogenesis of obesity-related disease is also important.

OBJECTIVE

This retrospective study was conducted with the objectives of 1) comparison between groups exhibiting equivalent amounts of AF loss that resulted from distinct treatments (exercise and dietary restriction) with respect to degrees of improvement in obesity-related health risk factors and 2) determination of definite differences in the outcomes of obesity-related health risk in subjects receiving identical treatment (exercise) but exhibiting a remarkable difference in AF reduction.

DESIGN

In 66 subjects who completed a 12-week exercise or dietary restriction program, 17 parameters (systolic blood pressure [SBP] and diastolic blood pressure [DBP]; high-sensitivity C-reactive protein [hs-CRP]; leptin, adiponectin, tumor necrosis factor [TNF]-α, interleukin [IL]-6; alanine aminotransferase [ALT], gamma glutamyl transpeptidase [γGT]; lipid profile: high-density lipoprotein cholesterol [HDLC], triglyceride [TG]; fasting plasma glucose [FPG], hemoglobin A1c [HbA1c], homeostasis model assessment of insulin resistance (HOMA-IR); creatinine, uric acid; and maximal aerobic capacity [VO2 max]) were examined as indicators of obesity-related health risk.

RESULTS

Despite equivalent magnitudes of AF reduction (-29.5% versus -30.1%) in subjects in the exercise and dietary restriction groups (objective 1), ten parameters (SBP, DBP, HDLC, HOMA-IR, uric acid, creatinine, hs-CRP, adiponectin, IL-6, and VO2 max) showed significant differences. However, for large AF reduction differences (-30.1% versus -2.8%) between groups of subjects in the same exercise program (objective 2), only creatinine and VO2 max were different.

CONCLUSION

It is likely that AF reduction alone is not directly linked to improvement in obesity-related health risk factors, indicating the need for reexamination of the management for AF reduction (ie, lifestyle modification) rather than simply targeting reduction of AF.

Molecular mechanisms of muscle plasticity with exercise

The skeletal muscle phenotype is subject to considerable malleability depending on use. Low-intensity endurance type exercise leads to qualitative changes of muscle tissue characterized mainly by an increase in structures supporting oxygen delivery and consumption. High-load strength-type exercise leads to growth of muscle fibers dominated by an increase in contractile proteins. In low-intensity exercise, stress-induced signaling leads to transcriptional upregulation of a multitude of genes with Ca(2+) signaling and the energy status of the muscle cells sensed through AMPK being major input determinants. Several parallel signaling pathways converge on the transcriptional co-activator PGC-1α, perceived as being the coordinator of much of the transcriptional and posttranscriptional processes. High-load training is dominated by a translational upregulation controlled by mTOR mainly influenced by an insulin/growth factor-dependent signaling cascade as well as mechanical and nutritional cues. Exercise-induced muscle growth is further supported by DNA recruitment through activation and incorporation of satellite cells. Crucial nodes of strength and endurance exercise signaling networks are shared making these training modes interdependent. Robustness of exercise-related signaling is the consequence of signaling being multiple parallel with feed-back and feed-forward control over single and multiple signaling levels. We currently have a good descriptive understanding of the molecular mechanisms controlling muscle phenotypic plasticity. We lack understanding of the precise interactions among partners of signaling networks and accordingly models to predict signaling outcome of entire networks. A major current challenge is to verify and apply available knowledge gained in model systems to predict human phenotypic plasticity.

Muscle as a secretory organ

Skeletal muscle is the largest organ in the body. Skeletal muscles are primarily characterized by their mechanical activity required for posture, movement, and breathing, which depends on muscle fiber contractions. However, skeletal muscle is not just a component in our locomotor system. Recent evidence has identified skeletal muscle as a secretory organ. We have suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers and exert either autocrine, paracrine, or endocrine effects should be classified as "myokines." The muscle secretome consists of several hundred secreted peptides. This finding provides a conceptual basis and a whole new paradigm for understanding how muscles communicate with other organs such as adipose tissue, liver, pancreas, bones, and brain. In addition, several myokines exert their effects within the muscle itself. Many proteins produced by skeletal muscle are dependent upon contraction. Therefore, it is likely that myokines may contribute in the mediation of the health benefits of exercise.

Lack of exercise is a major cause of chronic diseases

Chronic diseases are major killers in the modern era. Physical inactivity is a primary cause of most chronic diseases. The initial third of the article considers: activity and prevention definitions; historical evidence showing physical inactivity is detrimental to health and normal organ functional capacities; cause versus treatment; physical activity and inactivity mechanisms differ; gene-environment interaction (including aerobic training adaptations, personalized medicine, and co-twin physical activity); and specificity of adaptations to type of training. Next, physical activity/exercise is examined as primary prevention against 35 chronic conditions [accelerated biological aging/premature death, low cardiorespiratory fitness (VO2max), sarcopenia, metabolic syndrome, obesity, insulin resistance, prediabetes, type 2 diabetes, nonalcoholic fatty liver disease, coronary heart disease, peripheral artery disease, hypertension, stroke, congestive heart failure, endothelial dysfunction, arterial dyslipidemia, hemostasis, deep vein thrombosis, cognitive dysfunction, depression and anxiety, osteoporosis, osteoarthritis, balance, bone fracture/falls, rheumatoid arthritis, colon cancer, breast cancer, endometrial cancer, gestational diabetes, pre-eclampsia, polycystic ovary syndrome, erectile dysfunction, pain, diverticulitis, constipation, and gallbladder diseases]. The article ends with consideration of deterioration of risk factors in longer-term sedentary groups; clinical consequences of inactive childhood/adolescence; and public policy. In summary, the body rapidly maladapts to insufficient physical activity, and if continued, results in substantial decreases in both total and quality years of life. Taken together, conclusive evidence exists that physical inactivity is one important cause of most chronic diseases. In addition, physical activity primarily prevents, or delays, chronic diseases, implying that chronic disease need not be an inevitable outcome during life.

Septic shock: desperately seeking treatment

Septic shock results from the dysregulation of the innate immune response following infection. Despite major advances in fundamental and clinical research, patients diagnosed with septic shock still have a poor prognostic outcome, with a mortality rate of up to 50%. Indeed, the reasons leading to septic shock are still poorly understood. First postulated 30 years ago, the general view of septic shock as an acute and overwhelming inflammatory response still prevails today. Recently, the fact that numerous clinical trials have failed to demonstrate any positive medical outcomes has caused us to question our fundamental understanding of this condition. New and sophisticated technologies now allow us to accurately profile the various stages and contributory components of the inflammatory response defining septic shock, and many studies now report a more complex inflammatory response, particularly during the early phase of sepsis. In addition, novel experimental approaches, using more clinically relevant animal models, to standardize and stratify research outcomes are now being argued for. In the present review, we discuss the most recent findings in relation to our understanding of the underlying mechanisms involved in septic shock, and highlight the attempts made to improve animal experimental models. We also review recent studies reporting promising results with two vastly different therapeutic approaches influencing the renin-angiotensin system and applying mesenchymal stem cells for clinical intervention.

Skeletal muscle predicts ventilator-free days, ICU-free days, and mortality in elderly ICU patients

INTRODUCTION

As the population ages, the number of injured elderly is increasing. We sought to determine if low skeletal muscle mass adversely affected outcome in elderly patients following trauma.

METHODS

Patients ≥ 65 years of age with an admission abdominal computed tomography scan and requiring intensive care unit (ICU) stay at a Level I trauma center in 2009-2010 were reviewed. Muscle cross-sectional area at the 3rd lumbar vertebra was quantified and muscle index, a normalized measure of muscle mass, was calculated and related to clinical parameters including ventilator-free days, ICU-free days, and mortality. Using previously established sex-specific, muscle index cut-points, patients were then categorized as sarcopenic or non-sarcopenic and differences in clinical outcomes between these two groups were also compared. We also examined muscle index as a continuous variable relative to the same clinical outcomes.

RESULTS

There were 149 severely injured elderly patients (median age 79 years) enrolled in this study of which 71% were sarcopenic. Of the patients who were sarcopenic, 9% were underweight, 44% normal weight, and 47% overweight/obese as per body mass index (BMI) classifications. The overall mortality rate was 27% and univariate analysis demonstrated higher mortality among those who were sarcopenic (32% vs. 14%, P = 0.018). After controlling for age, sex, and injury severity, multiple logistic regression demonstrated that increased muscle index was significantly associated with decreased mortality (OR per unit muscle index = 0.93, 95% CI: 0.875-0.997, P = 0.025). In addition, multivariate linear regression showed that sarcopenia, but not muscle index, was associated with decreased ventilator-free (P = 0.004) and ICU-free days (P = 0.002). Neither BMI, serum albumin nor total adipose tissue on admission were indicative of survival, ventilator-free or ICU-free days.

CONCLUSIONS

Sarcopenia is highly prevalent in the elderly population with traumatic injuries. Traditional measures of nutritional assessment, such as BMI and serum albumin, do not accurately predict outcome in the injured elderly. Sarcopenia, however, represents a potential new predictor for mortality, discharge disposition, and ICU utilization. Measurement of muscularity allows for the early identification of at-risk patients who may benefit from aggressive and multidisciplinary nutritional and rehabilitative strategies.

Land-based versus aquatic resistance therapeutic exercises for older women with sarcopenic obesity: study protocol for a randomised controlled trial

BACKGROUND

Sarcopenic obesity is a health condition that combines excess adipose tissue and loss of muscle mass and strength. Sarcopenic obesity predisposes to more functional disabilities than obesity or sarcopenia alone. Progressive resistance exercises are recommended for older people as a potential treatment for sarcopenia and also for obesity. However, there is a lack of evidence indicating which programmes are best applied to older people, and no studies have investigated their effects on sarcopenic obese people. The aims of this protocol study are to investigate and compare the efficacy of land-based and aquatic resistance exercise programmes on improving muscle performance, functional capacity and quality of life of older women with sarcopenic obesity.

METHODS/DESIGN

This is a protocol study for a parallel randomised controlled clinical trial. Eligible participants are older women (≥65 years) with a body mass index ≥30 kg/m 2 and hand grip strength ≤21 kg force. A total sample of 36 participants will be randomly allocated to one of the intervention groups in blocks of three: land-based, aquatic or control. Each intervention group will undergo 2-week sessions of a 10-week therapeutic exercise programme for strength, power and endurance training of the lower-limb muscles. Participants in the control group will not participate in any strengthening activity for lower limbs and will receive telephone calls once a week. Baseline and final evaluation of outcomes will encompass muscle performance of the lower limbs assessed by an isokinetic dynamometer; functional tests of usual walking speed, maximal walking speed (shuttle walking test), stair speed and the Short Physical Performance Battery; and health-related quality of life (Medical Outcomes Study Short Form Questionnaire - SF-36). Data collectors will be blinded to randomisation and will not be in touch with participants during the interventions.

DISCUSSION

This study is the first randomised controlled trial designed to evaluate resistance exercises in older patients with sarcopenic obesity. If our hypothesis proves correct, both intervention programmes will be effective, with the land-based exercises conferring better results in muscle performance.

TRIAL REGISTRATION

Registro Brasileiro de Ensaios Clínicos: RBR-9p5q67.

The effect of physical activity on mediators of inflammation

Being physically active and undertaking exercise on a regular basis are critical lifestyle behaviours which protect against the development of numerous chronic metabolic conditions. One of the key mechanisms by which physical activity exerts favourable health effects appears to be due to its capacity to reduce chronic low-grade inflammation. Single bouts of exercise have a potent anti-inflammatory influence with recent advances describing important effects of acute exercise on inflammatory mediators produced within skeletal muscle (myokines), adipose tissue (adipokines) and leucocytes. The accumulated effects of physical activity or exercise training on systemic inflammation have been studied widely within epidemiological research; however, information from intervention trials is still emerging. Current data suggest that the most marked improvements in the inflammatory profile are conferred with exercise performed at higher intensities, with combined aerobic and resistance exercise training potentially providing the greatest benefit. The purpose of this review is to describe recent advances in our understanding surrounding the acute and chronic effects of physical activity on key mediators of inflammation. Within this, particular attention is given to the interleukin-6 system owing to its apparent centrality in mediating the anti-inflammatory effects of exercise.

Exercise and the aging endothelium

The endothelium plays a critical role in the maintenance of cardiovascular health by producing nitric oxide and other vasoactive materials. Aging is associated with a gradual decline in this functional aspect of endothelial regulation of cardiovascular homeostasis. Indeed, age is an independent risk factor for cardiovascular diseases and is in part an important factor in the increased exponential mortality rates from vascular disease such as myocardial infarction and stroke that occurs in the ageing population. There are a number of mechanisms suggested to explain age-related endothelial dysfunction. However, recent scientific studies have advanced the notion of oxidative stress and inflammation as the two major risk factors underlying aging and age-related diseases. Regular physical activity, known to have a favorable effect on cardiovascular health, can also improve the function of the ageing endothelium by modulating oxidative stress and inflammatory processes, as we discuss in this paper.

Skeletal muscle: an endocrine organ

Tropism and efficiency of skeletal muscle depend on the complex balance between anabolic and catabolic factors. This balance gradually deteriorates with aging, leading to an age-related decline in muscle quantity and quality, called sarcopenia: this condition plays a central role in physical and functional impairment in late life. The knowledge of the mechanisms that induce sarcopenia and the ability to prevent or counteract them, therefore, can greatly contribute to the prevention of disability and probably also mortality in the elderly. It is well known that skeletal muscle is the target of numerous hormones, but only in recent years studies have shown a role of skeletal muscle as a secretory organ of cytokines and other peptides, denominated myokines (IL6, IL8, IL15, Brain-derived neurotrophic factor, and leukaemia inhibitory factor), which have autocrine, paracrine, or endocrine actions and are deeply involved in inflammatory processes. Physical inactivity promotes an unbalance between these substances towards a pro-inflammatory status, thus favoring the vicious circle of sarcopenia, accumulation of fat - especially visceral - and development of cardiovascular diseases, type 2 diabetes mellitus, cancer, dementia and depression, according to what has been called "the diseasome of physical inactivity".

A comparison of sex-specific immune signatures in Gulf War illness and chronic fatigue syndrome

Background

Though potentially linked to the basic physiology of stress response we still have no clear understanding of Gulf War Illness (GWI), a debilitating condition presenting complex immune, endocrine and neurological symptoms. Here we compared male (n = 20) and female (n = 10) veterans with GWI separately against their healthy counterparts (n = 21 male, n = 9 female) as well as subjects with chronic fatigue syndrome/ myalgic encephalomyelitis (CFS/ME) (n = 12 male, n = 10 female).

Methods

Subjects were assessed using a Graded eXercise Test (GXT) with blood drawn prior to exercise, at peak effort (VO2 max) and 4-hours post exercise. Using chemiluminescent imaging we measured the concentrations of IL-1a, 1b, 2, 4, 5, 6, 8, 10, 12 (p70), 13, 15, 17 and 23, IFNγ, TNFα and TNFβ in plasma samples from each phase of exercise. Linear classification models were constructed using stepwise variable selection to identify cytokine co-expression patterns characteristic of each subject group.

Results

Classification accuracies in excess of 80% were obtained using between 2 and 5 cytokine markers. Common to both GWI and CFS, IL-10 and IL-23 expression contributed in an illness and time-dependent manner, accompanied in male subjects by NK and Th1 markers IL-12, IL-15, IL-2 and IFNγ. In female GWI and CFS subjects IL-10 was again identified as a delineator but this time in the context of IL-17 and Th2 markers IL-4 and IL-5. Exercise response also differed between sexes: male GWI subjects presented characteristic cytokine signatures at rest but not at peak effort whereas the opposite was true for female subjects.

Conclusions

Though individual markers varied, results collectively supported involvement of the IL-23/Th17/IL-17 axis in the delineation of GWI and CFS in a sex-specific way.

NF-κB pathway activators as potential ageing biomarkers: targets for new therapeutic strategies

Chronic inflammation is a major biological mechanism underpinning biological ageing process and age-related diseases. Inflammation is also the key response of host defense against pathogens and tissue injury. Current opinion sustains that during evolution the host defense and ageing process have become linked together. Thus, the large array of defense factors and mechanisms linked to the NF-κB system seem to be involved in ageing process. This concept leads us in proposing inductors of NF-κB signaling pathway as potential ageing biomarkers. On the other hand, ageing biomarkers, represented by biological indicators and selected through apposite criteria, should help to characterize biological age and, since age is a major risk factor in many degenerative diseases, could be subsequently used to identify individuals at high risk of developing age-associated diseases or disabilities. In this report, some inflammatory biomarkers will be discussed for a better understanding of the concept of biological ageing, providing ideas on eventual working hypothesis about potential targets for the development of new therapeutic strategies and improving, as consequence, the quality of life of elderly population.

Muscle wasting in cancer

Skeletal muscle loss appears to be the most significant clinical event in cancer cachexia and is associated with a poor outcome. With regard to such muscle loss, despite extensive study in a range of models, there is ongoing debate as to whether a reduction in protein synthesis, an increase in degradation or a combination of both is the more relevant. Each model differs in terms of key mediators and the pathways activated in skeletal muscle. Certain models do suggest that decreased synthesis accompanied by enhanced protein degradation via the ubiquitin proteasome pathway (UPP) is important. Murine models tend to involve rapid development of cachexia and may represent more acute muscle atrophy rather than the chronic wasting observed in humans. There is a paucity of human data both at a basic descriptive level and at a molecular/mechanism level. Progress in treating the human form of cancer cachexia can only move forwards through carefully designed large randomised controlled clinical trials of specific therapies with validated biomarkers of relevance to underlying mechanisms. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.

Effects of chronic swimming training and oestrogen therapy on coronary vascular reactivity and expression of antioxidant enzymes in ovariectomized rats

The aim of this study was to evaluate the effects of swimming training (SW) and oestrogen replacement therapy (ERT) on coronary vascular reactivity and the expression of antioxidant enzymes in ovariectomized rats. Animals were randomly assigned to one of five groups: sham (SH), ovariectomized (OVX), ovariectomized with E2 (OE2), ovariectomized with exercise (OSW), and ovariectomized with E2 plus exercise (OE2+SW). The SW protocol (5×/week, 60 min/day) and/or ERT were conducted for 8 weeks; the vasodilator response to bradykinin was analysed (Langendorff Method), and the expression of antioxidant enzymes (SOD-1 and 2, catalase) and eNOS and iNOS were evaluated by Western blotting. SW and ERT improved the vasodilator response to the highest dose of bradykinin (1000 ng). However, in the OSW group, this response was improved at 100, 300 and 1000 ng when compared to OVX (p<0,05). The SOD-1 expression was increased in all treated/trained groups compared to the OVX group (p<0,05), and catalase expression increased in the OSW group only. In the trained group, eNOS increased vs. OE2, and iNOS decreased vs. SHAM (p<0,05). SW may represent an alternative to ERT by improving coronary vasodilation, most likely by increasing antioxidant enzyme and eNOS expression and augmenting NO bioavailability.