The impact of one session resistance exercise on plasma adiponectin and RBP4 concentration in trained and untrained healthy young men

Acute and Chronic Effects of Strength Training on Plasma Levels of Adipokines in Man

Adipose tissue is specialized cells that produce and release adipokines. Exercise may modulate adipokine production in adipocytes. The aim of this longitudinal study was to evaluate the acute and chronic effects of strength training (ST) on plasma levels of adiponectin, leptin, and resistin. Twelve untrained young male participants (23.42±2.67 years) were selected. The training protocol consisted of 3 exercises, with 3 sets of 65% of 1RM (one-repetition maximum) with pause of 90 s between sets with duration of 5 s/repetition (2 s conc/3 s ecc), 3 times a week for 10 weeks. Blood was collected at four time points: before and after the first ST session and before and after the last ST session. The comparisons between adipokine levels before and after the same training session showed acute changes, while the comparisons between levels before or after the first session versus before or after the last session revealed chronic alterations. ST increased adiponectin levels after the first exercise session in comparison to levels before this session [50 952 (46 568-51 894) pg/mL vs. 52 981 (49 901-54 467) pg/mL, p=0.019]. Similar differences were observed for resistin levels, which were higher after the last session compared to before [4 214.4 (±829) pg/mL vs. pre-S30 2 251.3 (±462.2) pg/mL, p=0.0008] and in the comparison between after the last and after the first ST sessions [4 214.4 (±829.0) pg/mL vs. 1 563.7 (±284.8) pg/mL, p=0.004]. Leptin levels acutely changed in the last training session. ST produced acute and chronic changes in plasma adipokines.

Exerkines and long-term synaptic potentiation: Mechanisms of exercise-induced neuroplasticity

Physical exercise may improve cognitive function by modulating molecular and cellular mechanisms within the brain. We propose that the facilitation of long-term synaptic potentiation (LTP)-related pathways, by products induced by physical exercise (i.e., exerkines), is a crucial aspect of the exercise-effect on the brain. This review summarizes synaptic pathways that are activated by exerkines and may potentiate LTP. For a total of 16 exerkines, we indicated how blood and brain exerkine levels are altered depending on the type of physical exercise (i.e., cardiovascular or resistance exercise) and how they respond to a single bout (i.e., acute exercise) or multiple bouts of physical exercise (i.e., chronic exercise). This information may be used for designing individualized physical exercise programs. Finally, this review may serve to direct future research towards fundamental gaps in our current knowledge regarding the biophysical interactions between muscle activity and the brain at both cellular and system levels.

The effect of combined exercises on the plasma levels of retinol-binding protein 4 and its relationship with insulin resistance and hepatic fat content in postmenopausal women with nonalcoholic fatty liver disease

BACKGROUND

Evidence suggests increased serum levels of retinol-binding protein 4 (RBP4) in postmenopausal women with nonalcoholic fatty liver disease (NAFLD). This study investigated the effect of combined exercises on the plasma levels of RBP4 and its relationship with insulin resistance and hepatic fat content in these women.

METHODS

This quasi-experimental study randomly assigned 24 women with fatty liver and a mean age of 56.18±4.58 years to an experimental group and a control group. The experimental group participated in ten-week incremental endurance-resistance training as combined exercises three sessions a week. Fatty liver was diagnosed with ultrasound, RBP4 levels were measured and insulin resistance was determined using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Between-group data were analyzed using ANCOVA, within-group data using the dependent t-test and Wilcoxon test and relationships between RBP4 and variables using Spearman and Pearson correlation coefficients.

RESULTS

Ten weeks of combined exercises significantly decreased RBP4 levels (P=0.000), HOMA-IR (P=0.011) and hepatic fat levels (P=0.000) in the experimental group compared to in the controls. The posttest showed significant correlations between RBP4 levels and hepatic fat levels (P=0.002) and no correlations between RBP4 levels and insulin resistance (P=0.116).

CONCLUSIONS

Combined exercises significantly reduced serum levels of RBP4 in postmenopausal women with fatty liver. RBP4 was not related to insulin resistance and effects of RBP4 on hepatic fat regulation were independent of the effects of insulin resistance.

Acute moderate-intensity exercise increases total antioxidant capacity and anti-inflammatory responses in competitive cyclists: The role of adiponectin

High-intensity exercise can elicit acute changes in the biochemical and physiological processes in the body of an athlete, including increased oxidative stress and inflammation. The purpose of this study was to explore the effect of acute moderate-intensity exercise on total antioxidant capacity (TAC) and serum levels of anti-inflammatory adiponectin (APN), and inflammatory markers in competitive cyclists. Ten male cyclists (age 15–26 years, body mass index 19.4–24.7 kg/m2) participated in this study. Each subject performed the maximal oxygen uptake test (VO2peak) and completed a 10-min cycling exercise at a workload of 50% of the peak of VO2peak. Blood samples were collected on three different occasions: after an overnight fasting and at the exercise workloads of 50% and 100% VO2peak. We measured APN, TAC, inflammatory markers as well as assessed nutrient and energy intake for each participant. Baseline concentration of serum APN (10.92 µg/mL) significantly increased at 50% and at 100% VO2peak. In addition, TAC also increased after acute exercise (0.079 vs 0.093 nmol/µL). The concentration of APN at 50% VO2peak positively correlated with the CRP ( r = 0.640, p = 0.046) and negatively correlated with TNF-α ( r = −0.696, p = 0.025). This test showed that short (10 min) and medium-intensity (50% VO2peak) exercise activity in trained athletes evoked beneficial antioxidant and anti-inflammatory responses. Importantly, this response correlates with the increase in APN levels thereby showing that highly trained individuals have beneficial responses originating from adipose tissue. Our observations show that a short training at moderate activity can be an important preservative strategy during the recovery training period.

Therapeutic Approaches to Nonalcoholic Fatty Liver Disease: Exercise Intervention and Related Mechanisms

Exercise training ameliorates nonalcoholic fatty liver disease (NAFLD) as well as obesity and metabolic syndrome. Although it is difficult to eliminate the effects of body weight reduction and increased energy expenditure-some pleiotropic effects of exercise training-a number of studies involving either aerobic exercise training or resistance training programs showed ameliorations in NAFLD that are independent of the improvements in obesity and insulin resistance. In vivo studies have identified effects of exercise training on the liver, which may help to explain the "direct" or "independent" effect of exercise training on NAFLD. Exercise training increases peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression, improves mitochondrial function and leads to reduced hepatic steatosis, inflammation, fibrosis, and tumor genesis. Crosstalk between the liver and adipose tissue, skeletal muscle and the microbiome is also a possible mechanism for the effect of exercise training on NAFLD. Although numerous studies have reported benefits of exercise training on NAFLD, the optimal duration and intensity of exercise for the prevention or treatment of NAFLD have not been established. Maintaining adherence of patients with NAFLD to exercise training regimes is another issue to be resolved. The use of comprehensive analytical approaches to identify biomarkers such as hepatokines that specifically reflect the effect of exercise training on liver functions might help to monitor the effect of exercise on NAFLD, and thereby improve adherence of these patients to exercise training. Exercise training is a robust approach for alleviating the pathogenesis of NAFLD, although further clinical and experimental studies are required.

Excess Blood Flow Response to Acute Resistance Exercise in Individuals Who are Obese or Nonobese

Lipford, GF, Evans, RK, Acevedo, EO, Wolfe, LG, and Franco, RL. Excess blood flow response to acute resistance exercise in individuals who are obese or nonobese. J Strength Cond Res 31(11): 3120-3127, 2017-Resistance exercise (RE) is a commonly recommended treatment option for obese individuals. However, little is known regarding alterations in vasodilatory responses to RE, which could impair exercise tolerance. No studies to date have compared microvascular vasodilatory capacity, assessed by excess blood flow (EBF), responses in individuals who are obese or nonobese following acute RE. The purpose of the study was to evaluate EBF before and up to 24-hour after a single RE bout in obese (n = 18, 38.1 ± 7.64% body fat) and nonobese (n = 10, 23.6 ± 4.03% body fat) individuals who volunteered to participate. Each subject completed a leg flexion and knee extension one repetition maximum (1RM) test, and subsequently completed 4 sets of 8 repetitions at 85% of 1RM. Excess blood flow, adiponectin, and tumor necrosis factor α (TNF-α) were evaluated at baseline (PRE-RE), immediately after (POST-RE), and 1 (POST-1) and 24 (POST-24) hours after exercise. A repeated-measures analysis of variance revealed a significant interaction for EBF between the 2 groups (p = 0.029). The estimated marginal means plot suggested that obese individuals had a significant increase in POST-RE EBF in comparison with PRE-RE EBF (428.54 ± 261.59 vs. 547.00 ± 311.15 ml/100 ml/min·s; p = 0.046). In addition, EBF significantly decreased at POST-24 in comparison with POST-RE in the obese individuals (547.00 ± 311.15 vs. 389.33 ± 252.32 ml/100 ml/min·s; p = 0.011). Changes in EBF were not related to adiponectin or TNF-α. An acute bout of RE resulted in an opposite EBF response between nonobese and obese individuals immediately after RE. Furthermore, only the obese individuals displayed a significant increase in EBF immediately after RE, which was significantly reduced 24 hours after the RE bout. Microvascular vasodilatory capacity may alter the adaptive exercise response associated with RE, requiring alterations to frequency, intensity, and/or duration that are specific to populations of various body composition profiles.

Exercise-induced changes in inflammatory processes: Implications for thrombogenesis in cardiovascular disease

Sedentary lifestyle is a risk factor and a strong predictor for chronic disease and premature death. Low-grade inflammation has been proved a key player in the pathogenesis of cardiovascular disease. Inflammatory processes have been also involved in maintaining the balance between coagulation and fibrinolysis. In addition, an inverse linear dose-response relation between physical activity and mortality risks has also been reported. However, the favorable effects of structured exercise programs and the independent contribution of physical activity to cardiovascular risk are still under investigation. In response to heavy exercise, interleukin-6 (IL-6) is secreted by contracting skeletal muscles, followed by an acute reactant release of C-reactive protein (CRP). Both CRP and IL-6 can stimulate monocyte tissue factor production, provoke platelet hyperreactivity, promote fibrinogen biosynthesis, and enhance microparticle formation and erythrocyte aggregability, thus triggering prothrombotic state. By contrast, regular exercise and physical activity are protective against all-cause mortality through suppressing pro-inflammatory cytokine production, enhancing anti-inflammatory mediators and antioxidant development, and promoting fibrinolytic activity. Low-load resistance exercise also plays an advantageous role in thrombogenesis by reducing inflammatory processes and potentiating fibrinolytic features. In the present review article, we provide an overview of the impact of different modes and intensities of physical activity on vascular inflammation and thrombogenesis.

Effect of endurance training on retinol-binding protein 4 gene expression and its protein level in adipose tissue and the liver in diabetic rats induced by a high-fat diet and streptozotocin

AIMS/INTRODUCTION

The present study was designed to investigate from which tissues the decrease in retinol-binding protein 4 (RBP4) expression could contribute to the improvement of serum RBP4 and insulin resistance (IR) after endurance training.

MATERIALS AND METHODS

Male 7-week-old Wistar rats were randomly assigned into four groups including control (C), trained (T), diabetic control (DC) and trained diabetic (TD). At 8 weeks-of-age, diabetes was induced by a high-fat diet and intraperitoneal injection of low-dose streptozotocin (STZ; 35 mg/kg). Rats in the T and TD groups carried out a 7-week exercise program on a motorized treadmill (15-20 m/min for 20 min/day for 5 weeks), whereas the C and DC remained sedentary in their cages. Tissues gene expression and protein levels of RBP4 were assessed by using real-time polymerase chain reaction and western blot, respectively, while serum RBP4 was measured using an enzyme-linked immunosorbent assay kit.

RESULTS

Exercise significantly improved IR and reduced serum concentration of RBP4 in the TD group. This reduction of serum RBP4 was accompanied by decreased RBP4 protein expression in visceral fat tissue. In contrast, exercise had no significant effect on RBP4 expression in liver and subcutaneous fat tissue in the TD group. Exercise also significantly decreased RBP4 gene expression in visceral fat tissue and muscle, whereas the effect of exercise on liver RBP4 messenger ribonucleic acid expression was not significant.

CONCLUSIONS

The present study showed that the mechanism for RBP4 reducing the effect of endurance training could involve decreased RBP4 messenger ribonucleic acid expression and its protein level in adipose tissue in STZ-induced diabetic rats.

Changes of serum retinol binding protein 4 levels following 8 weeks moderate aerobic exercise

Purpose

The purpose of this study was to examine the effects of 8 weeks moderate intensity aerobic exercise on serum retinol binding protein 4 (RBP4) levels in female athletes.

Methods

Twenty female karate athletics were randomly assigned to one of the exercise group (n = 10) or control group (n = 10). The training group performed endurance training 3 days a week for 8 weeks at an intensity corresponding to 50-60% individual maximum oxygen consumption for 45 min.

Results

Body mass and body mass index increased (P < 0.05) after 8 weeks aerobic exercise compared to the control group. For waist to hip ratio (WHR), body fat percentage and maximal oxygen consumption there were no significant differences between the exercise group and the control group. There were virtually no changes in body fat percentage, fasting glucose, insulin, insulin resistance and RBP4 levels after 8 weeks training.

Conclusion

Serum RBP4 level was not affected by 8-week moderate aerobic exercise in female athletes.

The association of carotid intima media thickness with retinol binding protein-4 and total and high molecular weight adiponectin in type 2 diabetic patients

BACKGROUND

The aim of this study was to investigate whether carotid intima media thickness (CIMT) is associated with serum level of retinol- binding protein-4 (RBP4) and total and high molecular weight (HMW) adiponectin in type 2 diabetes (T2DM) without clinical symptom of atherosclerotic disease.

METHOD

101 type 2 diabetic patients (mean age, 53.63 ± 8.42 years) and 42 body mass index (BMI) matched control (mean age 50.1 ± 8.4) were recruited. The CIMT was assessed by using B-mode ultrasonography, while serum levels of RBP4 and total and HMW adiponectin were measured by using enzyme linked immunosorbant assay (ELISA). Linear regression analysis was performed with CIMT as dependent variable and adipokines and cardio metabolic risk factors as independent variables.

RESULT

The CIMT was higher in diabetic group compared to control group (p <0.05). The mean concentration of RBP4 and total and HMW adiponectin did not differ between two groups.Age (B = 0.44 P <0.05), blood pressure (B = 0.37 P = <0.05), waist circumference (B = -0.21 P <0.05) and TG (B = 0.1 P <0.05) were identified as independent predictors for CIMT in diabetic group, while RBP4 and adiponectin were not associated with CIMT neither in diabetic group nor in control group.

CONCLUSION

In conclusion, the present study showed that serum levels of RBP4 or total and HMW adiponectin were not potential predictors of CIMT in type 2 diabetic patients who exposed to this risk factor at least for nine years.

Time course responses of serum GH, insulin, IGF-1, IGFBP1, and IGFBP3 concentrations after heavy resistance exercise in trained and untrained men

To investigate the effect of heavy resistance exercise on IGF-1 system, 19 healthy trained men and 15 healthy untrained men volunteered to participate in this study. The subjects were randomly divided into experimental and control groups. Subjects of experimental groups were forced to perform a heavy resistance exercise with the intensity of 70-80% of 1RM in selected movements. The blood samples were taken from all subjects four times; before (T1), immediately after (T2), 5 (T3), and 8 (T4) hours after exercise. Analysis of data showed that a session of heavy resistance exercise induced significant increase in GH at T2 (P < 0.05) and a significant decrease in insulin at T4 (P < 0.05) and a significant decrease in IGFBP3 at T4 (P < 0.05) in trained group. In untrained group, no significant change in any of the variables was observed. However, the procedure of response in variables was almost similar in two experimental groups. Although, the exercise did not appreciably affect IGF-1 levels, it decreased in all groups at length of time after exercise. In addition, the exercise did not have any notable effect on IGFBP1 levels over time. In conclusion, the findings of this study indicate that the intense resistance exercise can lead to changes in blood concentrations of IGF-1 system components which are observable in blood circulation over time and the amounts of changes depend on subjects' fitness levels and exercise variables.