High-intensity endurance training improves adiponectin mRNA and plasma concentrations

The 40-min HIIT acutely induced bone formation which was likely through the increases in muscle derived interleukin 6 and adiponectin activation: The 16 weeks of HIIT intervention, longitudinal randomized controlled trial

PURPOSE

There is some controversy regarding cytokines released from adipocytes, particularly adiponectin, leptin, and IL6 that regulate bone remodeling. In addition, IL6 is released from muscle contraction, which might have a distinct role in bone remodeling. Hence, this study investigated whether muscle contraction during a session of 40 min of high intensity interval training (40-min HIIT) and after 16 weeks of HIIT (16-wk HIIT) altered the release of those cytokines and bone remodeling in overweight women.

METHODS

In total, 22 overweight, premenopausal women were randomly assigned to either the exercise or the control group. The exercise participants engaged in the 40-min HIIT session at 80-90 % of their heart rate reserve (HRR) three times weekly for 16 weeks, while the control participants performed their routine daily activities. Blood was drawn after overnight fasting and immediately after completing the 40-min HIIT sessions to investigate the association of adiponectin, leptin, IL6, CTX, and P1NP through the acute effect of the 40-min HIIT sessions. This process was repeated after the 16-wk intervention program to observe the training effect of HIIT on cytokines linkage. The bone mineral density (BMD) levels of the distal tibia, femur, and lumbar spine were determined prior to and after the 16-wk intervention using dual-energy X-ray absorptiometry.

RESULTS

The P1NP level increased by 8.29-20.52 % (95 % CI) and by 2.91-15.54 % after completing the first and last bouts of the 40-min HIIT sessions, respectively. In addition, IL6 increased by 13.39-28.03 % (95 % CI), while serum CTX and adiponectin were unaltered from the acute effect of the 40-min HIIT sessions. There was an association between the increases in P1NP and adiponectin (r = 0.682, p = 0.015); however, the increase in P1NP was mostly associated with the increase in IL6 (r = 0.572, p = 0.054) after completing a 40-min HIIT session. After the 16-wk HIIT program, the resting adiponectin level of the exercise participants increased; however, this was associated with neither bone biomarkers nor BMD. The BMDs of the exercise participants were maintained; however, the tibial BMD of the control participants decreased with an increase in the resting CTX level after 16 weeks.

CONCLUSION

Muscle contraction during the 40-min HIIT session elevated the IL6 level, which might have subsequently enhanced bone formation. Furthermore, the association between acute changes in adiponectin and P1NP suggested the possibility of an increase in the sensitivity of the adiponectin receptor in osteoblasts.

Effects of Exercise Training on Inflammatory and Cardiometabolic Risk Biomarkers in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The interaction between type 2 diabetes mellitus (T2DM) and cardiometabolic morbidity and mortality stems from the progressive nature of inflammation underpinning both diseases. Exercise training is considered an effective treatment strategy for T2DM and cardiometabolic diseases.

OBJECTIVE

The current systematic review and meta-analysis investigated the effects of exercise training on inflammatory and cardiometabolic risk biomarkers in patients with T2DM.

DATA SOURCES

Electronic databases (PubMed/Medline, Embase, Cochrane Library, CINAHL, Google Scholar, Scopus, and Web of Science) were searched for randomized controlled trials (RCTs) from inception to January 2022. We used random effects models to estimate weighted mean differences with 95% confidence intervals.

STUDY SELECTION

Twenty-five RCTs were included (N = 1257 participants; mean age = 52 years). Included studies had moderate to good overall methodological quality (TESTEX = 9 (range 7-13).

RESULTS

Meta-analysis indicated that exercise training significantly increased adiponectin and decreased fasting insulin, homeostatic model assessment for insulin resistance, tumor necrosis factor-α, interleukin-6, and C-reactive protein (ps ≤ 0.05). Subgroup analysis by type of training indicated that aerobic exercise had the most consistent beneficial effects as compared to other types of exercise training; however, there was high heterogeneity among studies.

CONCLUSION

Different types of exercise training increase adiponectin levels and decrease pro-inflammatory cytokines such as TNF-α, IL-6, and CRP, as well as fasting insulin and insulin resistance markers in patients with T2DM. However, these effects were not beneficial for more commonly measured cardiometabolic risk factors (i.e., lipid profiles). Additional relevant clinical trials are required to confirm these results.

TRIAL REGISTRATION

This systematic review and meta-analysis was prospectively registered in the PROSPERO database (CRD42022307396).

Role of adiponectin in osteoarthritis

Osteoarthritis (OA) is a widespread and most common joint disease which leads to social cost increasing accompany with aging population. Surgery is often the final treatment option. The major progression of OA includes cartilage degradation caused by chondrocytes metabolism imbalance. So, the molecular mechanisms of action in chondrocytes may provide insights into treatment methods for OA. Adiponectin is an adipokine with many biological functions in the cell metabolism. Numerous studies have illustrated that adiponectin has diverse biological effects, such as inhibition of cell apoptosis. It regulates various functions in different organs, including muscle, adipose tissue, brain, and bone, and regulates skeletal homeostasis. However, the relationship between adiponectin and cell death in the progression of OA needs further investigation. We elaborate the structure and function and the effect of adiponectin and state the correlation and intersection between adiponectin, autophagy, inflammation, and OA. From the perspective of oxidative stress, apoptosis, pyroptosis, and autophagy, we discuss the possible association between adiponectin, chondrocyte metabolism, and inflammatory factor efforts in OA. What’s more, we summarize the possible treatment methods, including the use of adiponectin as a drug target, and highlight the potential future mechanistic research. In this review, we summarize the molecular pathways and mechanisms of action of adiponectin in chondrocyte inflammation and death and the pathogenesis of OA. We also review the research on adiponectin as a target for treating OA. These studies provide a novel perspective to explore more effective treatment options considering the complex interrelationship between inflammation and metabolism in OA.

Adipose and Skeletal Muscle Expression of Adiponectin and Liver Receptor Homolog-1 With Weight Loss and Aerobic Exercise

Context

Adiponectin is an adipokine mainly secreted by adipocytes that regulates the metabolism of lipids and glucose. Liver receptor homolog-1 (LRH-1), also named NR5A2, is a nuclear receptor that regulates lipid metabolism and homeostasis.

Objective

The purpose of this study was to compare adiponectin and LRH-1 messenger RNA (mRNA) expression in adipose tissue and LRH-1 expression in skeletal muscle between men and women at baseline and to study the effects of aerobic exercise (AEX) training or weight loss (WL) on their expression.

Methods

This hospital and university setting study included 62 overweight and obese men (n = 23) and women (n = 39) older than 45 years, of whom 41 completed 6 months of WL (n = 21) or AEX (n = 20). Outcomes included abdominal and gluteal adipose tissue and skeletal muscle gene expression.

Results

Adiponectin and LRH-1 mRNA expression in adipose tissue and LRH-1 mRNA expression in skeletal muscle is higher in women than in men (P < .05). Adiponectin mRNA expression in gluteal and abdominal adipose tissue did not change significantly after AEX or WL. LRH-1 mRNA expression increased both in adipose tissue and skeletal muscle after AEX (P < .05) and the change in muscle LRH-1 was different between the groups (P < .05). Adiponectin was positively correlated to LRH-1 in adipose tissue (P < .001). The change in maximal oxygen consumption related to the change in LRH-1 mRNA (r = 0.43; P = .01).

Conclusion

LRH-1, as a nuclear reporter, may activate adiponectin mRNA expression in adipose tissue and increases after AEX.

Comparative Efficacy of 5 Exercise Types on Cardiometabolic Health in Overweight and Obese Adults: A Systematic Review and Network Meta-Analysis of 81 Randomized Controlled Trials

BACKGROUND

Although regular exercise is recommended for preventing and treating overweight/obesity, the most effective exercise type for improving cardiometabolic health in individuals with overweight/obesity remains largely undecided. This network meta-analysis aimed to evaluate and rank the comparative efficacy of 5 exercise modalities on cardiometabolic health measures in individuals with overweight/obesity.

METHODS

A database search was conducted in MEDLINE, Embase, Scopus, and Web of Science from inception up to September 2020. The review focused on randomized controlled trials involving exercise interventions consisting of continuous endurance training, interval training, resistance training, combined aerobic and resistance training (combined training), and hybrid-type training. Exercise interventions aimed to improve somatometric variables, body composition, lipid metabolism, glucose control, blood pressure, cardiorespiratory fitness, and muscular strength. The Cochrane risk of bias tool was used to evaluate eligible studies. A random-effects network meta-analysis was performed within a frequentist framework. The intervention ranking was carried out using a Bayesian model where mean and SD were equal to the respective frequentist estimates.

RESULTS

A total of 4331 participants (59% female; mean age: 38.7±12.3 years) from 81 studies were included. Combined training was the most effective modality and hybrid-type training the second most effective in improving cardiometabolic health-related outcomes in these populations suggesting a higher efficacy for multicomponent exercise interventions compared to single-component modalities, that is, continuous endurance training, interval training, and resistance training. A subgroup analysis revealed that the effects from different exercise types were mediated by gender.

CONCLUSIONS

These findings corroborate the latest guidelines on exercise for individuals with overweight/obesity highlighting the importance of a multicomponent exercise approach to improve cardiometabolic health. Physicians and healthcare professionals should consider prescribing multicomponent exercise interventions to adults with overweight/obesity to maximize clinical outcomes.

REGISTRATION

URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42020202647.

Physiological Changes and Pathological Pain Associated with Sedentary Lifestyle-Induced Body Systems Fat Accumulation and Their Modulation by Physical Exercise

A sedentary lifestyle is associated with overweight/obesity, which involves excessive fat body accumulation, triggering structural and functional changes in tissues, organs, and body systems. Research shows that this fat accumulation is responsible for several comorbidities, including cardiovascular, gastrointestinal, and metabolic dysfunctions, as well as pathological pain behaviors. These health concerns are related to the crosstalk between adipose tissue and body systems, leading to pathophysiological changes to the latter. To deal with these health issues, it has been suggested that physical exercise may reverse part of these obesity-related pathologies by modulating the cross talk between the adipose tissue and body systems. In this context, this review was carried out to provide knowledge about (i) the structural and functional changes in tissues, organs, and body systems from accumulation of fat in obesity, emphasizing the crosstalk between fat and body tissues; (ii) the crosstalk between fat and body tissues triggering pain; and (iii) the effects of physical exercise on body tissues and organs in obese and non-obese subjects, and their impact on pathological pain. This information may help one to better understand this crosstalk and the factors involved, and it could be useful in designing more specific training interventions (according to the nature of the comorbidity).

The Role of Exercise Training on Low-Grade Systemic Inflammation in Adults with Overweight and Obesity: A Systematic Review

Low-grade systemic inflammation leads to critical alterations of several tissues and organs that can promote the appearance of non-communicable diseases, a risk that is increased in adults with obesity. Exercise training may counteract low-grade systemic inflammation, but there is a lack of consensus on how cytokines are modulated by training in adults with obesity. This study aimed of examining the effects of exercise training on circulating pro- and anti-inflammatory cytokines in adults with overweight and obesity, and whether exercise-induced fat mass reduction could mediate that effect. The search was conducted on Medline (Pubmed), SPORTDiscus and Web of Science databases from January 1998 to August 2021, using keywords pertaining to inflammation, exercise, and obesity. A total of 27 studies were selected, in which the circulating concentration levels of cytokines were analyzed. Endurance training (ET) decreased circulating CRP, IL-6 and TNF-α levels. TNF-α was reduced after resistance and concurrent training (CT), while IL-10 increased after resistance training (RT). Changes in IL-10 and CRP coincided with fat mass reduction, while decreased TNF-α levels were concomitant with changes in IL-6 and IL-10. Exercise training may reduce systemic low-grade inflammation profile in adults with overweight and obesity.

Perivascular adipose tissue and microvascular endothelial dysfunction in obese mice: Beneficial effects of aerobic exercise in adiponectin receptor (AdipoR1) and peNOSSer1177

In the present study, we aim to investigate the effects of aerobic physical training on perivascular adipose tissue (PVAT)-induced microvascular dysfunction of the femoral artery in obese mice. Microvascular reactivity was evaluated in control sedentary (c-SD), obese sedentary (o-SD) and obese trained (o-TR) male mice (C57BL6/JUnib), in the absence (PVAT-) or the presence (PVAT+) of femoral artery PVAT. We also analyzed protein expression, vascular nitric oxide (NO) production and reactive oxygen species (ROS) generation in PVAT. The blood glucose, triglycerides and total cholesterol levels were increased in the o-SD group, when compared with the c-SD group. The maximal responses and the potency to acetylcholine (ACh) were decreased in PVAT+ compared with PVAT- rings in the o-SD group, accompanied by a decrease in vascular protein expression of peNOS_Ser1177 , Cu/Zn-SOD, leptin receptor (Ob-R) and adiponectin receptor (AdipoR1). The protein expression of leptin increased and that of adiponectin decreased in PVAT. Additionally, vascular NO production was reduced and ROS generation was enhanced in PVAT in the o-SD group. Aerobic exercise training was effective for normalizing ACh relaxation response, vascular NO production and ROS generation in the o-TR group. It partially re-established the vascular protein expression of peNOS_Ser1177 and the PVAT leptin; normalized the vascular Cu/Zn-SOD and AdipoR1 protein expressions. In obese sedentary mice, the presence of PVAT is involved in the process of microvascular dysfunction of the femoral artery in a pathway associated with increased inflammation and ROS generation. The aerobic exercise training normalized the vascular response, the NO production and/or bioavailability and oxidative stress, with improved vascular expressions of Cu/Zn-SOD, peNOS_ser1177 , and AdipoR1.

Effect of different types of regular exercise on physical fitness in adults with overweight or obesity: Systematic review and meta-analyses

This systematic review examined the effect of exercise training interventions on physical fitness in adults with overweight or obesity and compared the effectiveness of different types of exercise training. Four electronic databases were searched. Articles were included if they described randomized controlled trials of exercise training interventions and their effect on maximal oxygen consumption or muscle strength in adults with overweight or obesity. Changes in outcome parameters were analyzed using random effects meta-analyses for different training types (aerobic, resistance, combined aerobic plus resistance, and high-intensity interval training). Eighty-eight articles satisfied the inclusion criteria of which 66 (3964 participants) could be included in the meta-analyses. All training types increased VO_2max (mean difference 3.82 ml/min/kg (95% CI 3.17, 4.48), P < 0.00001; I² = 48%). In direct comparisons, resistance training was less effective in improving VO_2max than aerobic training, HIIT was slightly more effective than aerobic training, and no difference between aerobic and combined aerobic plus resistance training was found. For muscle strength benefits, incorporation of resistance exercise in the training program is indicated. Exercise training increases VO_2max and muscle strength in adults with overweight or obesity. Differences between training types should be weighed with other needs and preferences when health professionals advise on exercise training to improve physical fitness.

Self-Selected Motivational Music on the Performance and Perceived Exertion of Runners

ABSTRACT

Clark, JC, Baghurst, T, and Redus, BS. Self-selected motivational music on the performance and perceived exertion of runners. J Strength Cond Res 35(6): 1656-1661, 2021-Music is used by athletes and exercisers to improve performance outcomes, but it is less known whether its properties can enhance performance at maximal intensity. This study measured subjects' performance time, average heart rate, and rating of perceived exertion (RPE) on a 1.5-mile running trial when listening to self-selected motivational music vs. no music. Subjects were 17 runners (male = 8, female = 9) who completed 2, 1.5-mile time trials in a repeated-measures randomized crossover design. For the music trial, subjects were asked to select and listen to a motivational song, which was scored by the subject for its motivational quotient using the Brunel Music Rating Inventory-2. Subjects improved mean performance time by 10 seconds and increased average heart rate by 4.5 b·min-1 in the motivational music condition, but neither were significantly different (p = 0.09, 0.10). However, the music condition significantly lowered subjects' RPE by 0.5 points (p = 0.02). That motivational music improved performance time, although not significant, is noteworthy considering the significantly lower RPE reported. Therefore, ergogenic qualities of motivational music may elicit a greater performance from experienced runners while simultaneously lowering perception of effort when working at maximal intensity.

What exercise prescription is optimal to improve body composition and cardiorespiratory fitness in adults living with obesity? A network meta-analysis

Current international guidelines recommend people living with obesity should be prescribed a minimum of 300 min of moderately intense activity per week for weight loss. However, the most efficacious exercise prescription to improve anthropometry, cardiorespiratory fitness (CRF) and metabolic health in this population remains unknown. Thus, this network meta-analysis was conducted to assess and rank comparative efficacy of different exercise interventions on anthropometry, CRF and other metabolic risk factors. Five electronic databases were searched for randomized controlled trials (RCTs) that compared different exercise modalities to improve anthropometry, CRF and/or metabolic health in adults living with obesity. RCTs were evaluated using the Cochrane risk of bias tool. A random effects network meta-analysis was performed within a frequentist framework. Of the 6663 articles retrieved, 45 studies with a total 3566 participants were included. Results reveal that while any type of exercise intervention is more effective than control, weight loss induced is modest. Interventions that combine high-intensity aerobic and high-load resistance training exert beneficial effects that are superior to any other exercise modality at decreasing abdominal adiposity, improving lean body mass and increasing CRF. Clinicians should consider this evidence when prescribing exercise for adults living with obesity, to ensure optimal effectiveness.

The effects of physical activity on adipokines in individuals with overweight/obesity across the lifespan: A narrative review

This narrative review summarizes current knowledge on the effects of physical activity (PA) on adipokine levels in individuals with overweight and obesity. Approximately 90 investigations including randomized control, cross-sectional and longitudinal studies that reported on the effects of a single session of PA (acute) or long-term PA (chronic) on adipokine levels in individuals with overweight/obesity were reviewed. The findings support the notion that there is consensus on the benefits of chronic exercise training-regardless of the mode (resistance vs. aerobic), intensity and cohort (healthy vs. diabetes)-on adipokine levels (such as tumour necrosis factor-alpha, interleukin-6, adiponectin, visfatin, omentin-1 and leptin). However, several confounding factors (frequency, intensity, time and type of exercise) can alter the magnitude of the effects of an acute exercise session. Available evidence suggests that PA, as a part of routine lifestyle behaviour, improves obesity complications by modulating adipokine levels. However, additional research is needed to help identify the most effective interventions to elicit the most beneficial changes in adipokine levels in individuals with overweight/obesity.

Interplay between hormones and exercise on hippocampal plasticity across the lifespan

The hippocampus is a brain structure known to play a central role in cognitive function (namely learning and memory) as well as mood regulation and affective behaviors due in part to its ability to undergo structural and functional changes in response to intrinsic and extrinsic stimuli. While structural changes are achieved through modulation of hippocampal neurogenesis as well as alterations in dendritic morphology and spine remodeling, functional (i.e., synaptic) changes can be noted through the strengthening (i.e., long-term potentiation) or weakening (i.e., long-term depression) of the synapses. While age, hormone homeostasis, and levels of physical activity are some of the factors known to module these forms of hippocampal plasticity, the exact mechanisms through which these factors interact with each other at a given moment in time are not completely understood. It is well known that hormonal levels vary throughout the lifespan of an individual and it is also known that physical exercise can impact hormonal homeostasis. Thus, it is reasonable to speculate that hormone modulation might be one of the various mechanisms through which physical exercise differently impacts hippocampal plasticity throughout distinct periods of an individual's life. The present review summarizes the potential relationship between physical exercise and different types of hormones (namely sex, metabolic, and stress hormones) and how this relationship may mediate the effects of physical activity during three distinct life periods, adolescence, adulthood, and senescence. Overall, the vast majority of studies support a beneficial role of exercise in maintaining hippocampal hormonal levels and consequently, hippocampal plasticity, cognition, and mood regulation.

Exercise improves adiposopathy, insulin sensitivity and metabolic syndrome severity independent of intensity

NEW FINDINGS

What is the central question of this study? What are the effects of work-matched continuous versus high-intensity interval training for 2 weeks on adiposopathy and cardiometabolic risk in obese adults with prediabetes? What is the main finding and its importance? Independent of intensity, short-term exercise improves adiposopathy and insulin sensitivity. While both exercise intensities reduced fasting leptin concentrations and metabolic syndrome severity, only interval training elevated total adiponectin. In contrast to previous work, neither condition altered high-molecular weight adiponectin. Collectively, these data suggest that short-term exercise can improve adipokine profiles, which may aid in reducing cardiometabolic risk prior to clinically meaningful weight loss in adults with prediabetes.

ABSTRACT

Individuals with prediabetes who are overweight and obese are at an increased risk of developing endocrine disruption of fat tissue, known as adiposopathy. While short-term exercise improves adipokine profiles, the effects of exercise intensity when matched for energy expenditure on adiposopathy are unknown. We hypothesized that high-intensity exercise would elicit greater changes in adiposopathy compared to moderate exercise. Twenty-eight overweight and obese adults (age: 60.9 ± 8.4 years; BMI: 33.0 ± 5.4 kg m-2 ) with prediabetes were randomized to twelve 60-min sessions of either moderate-continuous (CONT; n = 14) or high-intensity interval (INT; n = 14) exercise training. Total and high molecular weight (HMW) adiponectin and leptin were collected to assess adiposopathy (ratio of total adiponectin to leptin; A/L). Insulin sensitivity (SIIS ) was determined using a 75 g oral glucose tolerance test before and after training. Cardiometabolic risk factors were measured and a z-score was calculated to determine metabolic syndrome (MetS) severity. CONT and INT increased A/L (P < 0.01) and decreased leptin (P < 0.01) and MetS severity (P = 0.04). Neither intervention altered circulating levels of HMW adiponectin (P = 0.76) and only INT increased total adiponectin levels (P = 0.02). Both intensities increased insulin sensitivity (P < 0.01), which was associated with improvements in A/L (r = 0.47, P = 0.01). Additionally, increases in A/L tended to relate to decreased MetS severity (r = -0.36, P = 0.09). Short-term exercise intensity, when matched for energy expenditure, does not differentially affect improvements in adiposopathy in overweight and obese adults with prediabetes. Further, 12 bouts of exercise improved insulin sensitivity and MetS severity, suggesting that improving adipokine profiles may aid in reducing cardiometabolic risk.

Physical Activity Alters Inflammation in Older Adults by Different Intensity Levels

PURPOSE

To examine the influence of reallocating time spent at different objectively measured physical activity (PA) behaviors on markers of systemic inflammation in older women with different levels of metabolic risk.

METHODS

Accelerometer-based monitoring of PA was conducted in a population of community-dwelling older women (n = 111; age, 65-70 yr) for determination of daily sedentary time, time in light PA (LPA) and moderate-to-vigorous PA (MVPA). Blood samples were collected for the assessment of the systemic inflammatory markers C-reactive protein (CRP), fibrinogen, and adiponectin. Metabolic risk was assessed by standardized procedures based on definitions for the metabolic syndrome. Data were analyzed by linear regression models based on isotemporal substitution analysis.

RESULTS

Reallocating 30 min of sedentary time with either time in LPA (β = -0.47; P < 0.05) or MVPA (β = -0.42; P < 0.05) was related to reduced fibrinogen level, whereas no corresponding effect was evident when shifting time in LPA with time in MVPA, while holding sedentary time constant. In contrast, reallocating a 30-min period in sedentary (β = -0.70; P < 0.01) or LPA (β = -0.71; P < 0.01) with MVPA was associated with a significant reduction in CRP level, whereas no impact on CRP was observed when a period of sedentary behavior was replaced with LPA. Importantly, all significant influences on fibrinogen and CRP by displacement of different PA behaviors remained after adjustment for metabolic risk status among participants. No significant associations with adiponectin were observed.

CONCLUSIONS

Altogether, this work supports the existence of different intensity thresholds mediating beneficial effects of PA on important clinical markers of systemic inflammation in older women across different stages of disease prevention.

Impact of Exercise on Inflammatory Mediators of Metabolic and Vascular Insulin Resistance in Type 2 Diabetes

The development of obesity is cornerstone in the etiology of metabolic and vascular insulin resistance and consequently exacerbates glycemic control. Exercise is an efficacious first-line therapy for type 2 diabetes that improves insulin action through, in part, reducing hormone mediated inflammation. Together, improving the coordination of skeletal muscle metabolism with vascular delivery of glucose will be required for optimizing type 2 diabetes and cardiovascular disease treatment.

Accumulated or continuous exercise for glycaemic regulation and control: a systematic review with meta-analysis

OBJECTIVE

To compare the effectiveness of accumulating exercise in multiple bouts of at least 10 min throughout a day with exercise completed in a single bout (continuous or interval), or no exercise, on glycaemic control and regulation in inactive people without diagnosed glycaemic dysfunction.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Seven electronic databases were searched: CINAHL (EBSCO), Cochrane Library, EMBASE (Ovid), MEDLINE 1948-(Ovid), SCOPUS (Elsevier), SPORTDiscus (EBSCO) and Web of Science (ISI) with no restrictions on date and included all titles indexed up to February 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Articles reporting insufficiently active adults (19 to 64 years) without metabolic dysfunction, measuring glycaemic control or regulation following at least 6 weeks of aerobic exercise.

RESULTS

Only one study compared accumulated exercise to single-bout exercise with no significant effect on fasting glucose (95% CI: -0.04 to 0.24 mmol·L-1) or fasting insulin (95% CI: -1.79 to 9.85 pmol·L-1) reported 48 hours after the final bout. No studies compared accumulated exercise with no-exercise. Compared with no-exercise, single-bout exercise reduces insulin resistance (mean difference (MD): -0.53 pmol·L-1; 95% CI: -0.93 to -0.13). Insulin resistance was clearly reduced with moderate-intensity (-0.68 (-1.28 to -0.09)) but not with high-intensity (-0.38 (-1.20 to 0.44)) exercise. Single-bout exercise was not statistically more beneficial than no-exercise for glycated haemoglobin (HbA1c) (MD: -0.11 %; 95% CI: -0.24 to 0.02) in metabolically healthy individuals.

SUMMARY/CONCLUSION

The glycaemic response to accumulated exercise or single-bout exercise might not be different, however exercise intensity might influence the mechanisms generating the response.

PROSPERO REGISTRATION NUMBER

CRD42015025042.

Exercise training-induced effects on the abdominal subcutaneous adipose tissue phenotype in humans with obesity

Rodent studies have indicated that physical exercise may improve adipose tissue function. We investigated the effects of a 12-wk supervised, progressive exercise training program on adipocyte morphology and abdominal subcutaneous adipose tissue function in metabolically well-phenotyped subjects with obesity. Men with obesity ( n = 21) participated in a 12-wk supervised, progressive, combined exercise training program consisting of aerobic exercise (30 min at 70% of maximal power output 2 times/wk) and resistance exercise (3 × 10 repetitions at 60% of 1 repeated maximum 1 time/wk), with adjustment of exercise intensity every 4 wk. At baseline and after intervention, abdominal subcutaneous adipose tissue biopsies were collected to determine 1) adipocyte morphology, 2) gene expression of markers for lipolysis, inflammation, browning, adipokines, and mitochondrial biogenesis/function, 3) protein expression of mitochondrial oxidative phosphorylation (OXPHOS) complexes, and 4) ex vivo basal and β2-adrenergic stimulated lipolysis. The exercise training program, which increased maximal aerobic capacity ( P < 0.001) and muscle strength ( P < 0.001), slightly reduced adipose tissue mass (~0.7 kg, P = 0.021) but did not affect abdominal subcutaneous adipocyte size ( P = 0.744), adipose tissue gene expression of markers for mitochondrial biogenesis and function, browning, lipolysis, inflammation and adipokines, total OXPHOS protein content ( P = 0.789), or β2-adrenergic sensitivity of lipolysis ( P = 0.555). A 12-wk supervised, progressive exercise training program did not alter abdominal subcutaneous adipocyte morphology and adipose tissue gene/protein expression of markers related to adipose tissue function or β2-adrenergic sensitivity of lipolysis in male subjects with obesity.

NEW & NOTEWORTHY Studies that investigated the effects of exercise training on adipose tissue function in well-phenotyped humans are scarce. We demonstrate that 12 wk of supervised exercise training improved physical fitness and peripheral insulin sensitivity but did not alter abdominal subcutaneous adipocyte morphology, adipose tissue gene and protein expression of markers related to adipose tissue function, or β2-adrenergic receptor-mediated lipolysis in men with obesity. A prolonged and/or more intense training program may be required to improve human adipose tissue function.

A Systematic Review of the Effect of Lifestyle Interventions on Adipose Tissue Gene Expression: Implications for Carcinogenesis

OBJECTIVE

The mechanisms driving the associations between body weight and physical activity levels and multiple types of cancer are not yet well understood. The purpose of this review was to examine the effects of lifestyle interventions on proposed biomarkers of lifestyle and cancer risk at the level of adipose tissue in humans.

METHODS

Embase, MEDLINE, and CINAHL were searched by using keywords relating to exercise or diet interventions, adipose tissue biology, and outcomes of interest. Eligible studies included randomized clinical trials of exercise and/or dietary interventions in humans compared with control or other interventions, reporting the collection of subcutaneous abdominal adipose tissue.

RESULTS

Nineteen studies met criteria for inclusion. Eight studies modified dietary intake, five altered exercise levels, and six studies used a combination of both. Change in subcutaneous adipose tissue gene expression was most commonly observed with dietary weight loss, with a pattern of decrease in leptin, tumor necrosis factor alpha, and interleukin 6, along with an increase in adiponectin. There was limited change with exercise-only interventions or study arms.

CONCLUSIONS

Interventions leading to weight loss result in an altered gene expression of adipokines and inflammatory markers in subcutaneous adipose tissue, while less change in gene expression was noted with exercise alone.

Positive association between the changes in chemerin and adiponectin levels after weight reduction

PURPOSE

Adiponectin and chemerin have been reported their associations with insulin resistance and chronic inflammation. However, the relationship between adiponectin and chemerin themselves has not been fully elucidated. Therefore, we investigated the effects of changes in adiponectin and chemerin levels after a weight intervention.

MATERIALS AND METHODS

We recruited 136 healthy overweight or obese subjects from 2006 to 2009 and provided all participants lifestyle modification therapy with diet consultations over 16 weeks. We assigned the participants to take orlistat or sibutramine or to a no prescription group. We analyzed the data using paired t-tests, Pearson's partial correlation analysis, and stepwise multiple linear regression analysis.

RESULTS

∆ in chemerin was positively correlated with ∆ in adiponectin (r = 0.29, p < 0.01), and these trends were similar in the insulin-resistant (r = 0.35, p = 0.03) and insulin-sensitive (r = 0.27, p < 0.01) groups. In multiple regression analyses, Δadiponectin, ΔQUICKI (quantitative insulin-sensitivity check index), Δglucose, and ΔDBP were significantly associated with Δchemerin in the insulin-resistant group, and initial chemerin level, ΔQUICKI, ΔBMI (body mass index), and taking orlistat were associated with Δchemerin in the insulin-sensitive group.

CONCLUSIONS

Changes in chemerin levels were positively associated with changes in adiponectin levels. The association between these changes might be related to chemerin's dual inflammatory and anti-inflammatory effects or insulin resistance and insulin sensitivity enhancing effects, depending on the metabolic conditions. Additional studies are needed to clarify the mechanisms that underlie the effects of adiponectin and chemerin.

Effects of age and exercise training on coronary microvascular smooth muscle phenotype and function

Coronary microvascular function and blood flow responses during acute exercise are impaired in the aged heart but can be restored by exercise training. Coronary microvascular resistance is directly dependent on vascular smooth muscle function in coronary resistance arterioles; therefore, we hypothesized that age impairs contractile function and alters the phenotype of vascular smooth muscle in coronary arterioles. We further hypothesized that exercise training restores contractile function and reverses age-induced phenotypic alterations of arteriolar smooth muscle. Young and old Fischer 344 rats underwent 10 wk of treadmill exercise training or remained sedentary. At the end of training or cage confinement, contractile responses, vascular smooth muscle proliferation, and expression of contractile proteins were assessed in isolated coronary arterioles. Both receptor- and non-receptor-mediated contractile function were impaired in coronary arterioles from aged rats. Vascular smooth muscle shifted from a differentiated, contractile phenotype to a secretory phenotype with associated proliferation of smooth muscle in the arteriolar wall. Expression of smooth muscle myosin heavy chain 1 (SM1) was decreased in arterioles from aged rats, whereas expression of phospho-histone H3 and of the synthetic protein ribosomal protein S6 (rpS6) were increased. Exercise training improved contractile responses, reduced smooth muscle proliferation and expression of rpS6, and increased expression of SM1 in arterioles from old rats. Thus age-induced contractile dysfunction of coronary arterioles and emergence of a secretory smooth muscle phenotype may contribute to impaired coronary blood flow responses, but arteriolar contractile responsiveness and a younger smooth muscle phenotype can be restored with late-life exercise training. NEW & NOTEWORTHY Aging impairs contractile function of coronary arterioles and induces a shift of the vascular smooth muscle toward a proliferative, noncontractile phenotype. Late-life exercise training reverses contractile dysfunction of coronary arterioles and restores a young phenotype to the vascular smooth muscle.

The effect of exercise interventions on inflammatory biomarkers in healthy, physically inactive subjects: a systematic review

BACKGROUND

Increases in physical activity ameliorate low-grade systemic inflammation in disease populations such as type 2 diabetes mellitus and coronary artery disease. The effects of aerobic and resistance training (RT) on inflammatory biomarker profiles in non-disease, physically inactive individuals are unknown.

METHODS

A systematic review of randomized controlled trials measuring the effect of aerobic and resistance exercise on pro-inflammatory biomarkers in healthy, inactive adult populations was conducted. The available peer-reviewed literature was searched from January 1990 to June 2016 using the electronic databases PubMed and Scopus. A narrative synthesis of review findings was constructed with discussion of the impact of aerobic, resistance and combined training on C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-8, interleukin-1β and tumour necrosis factor-α.

RESULTS

The initial search revealed 1596 potentially relevant studies. Application of the study eligibility criteria led to the full-text review of 54 articles with 11 studies deemed suitable for inclusion. Review of related articles and the reference lists of the 54 full-text articles led to the inclusion of 2 additional studies. The review revealed inconsistent findings relating to the effect of aerobic training and RT on CRP and IL-6. Studies of older-aged adults (>65 years old) demonstrated the greatest and most consistent reduction in inflammatory biomarkers post-training intervention.

CONCLUSIONS

A paucity of evidence exists relating to the effect of exercise training on inflammatory markers in non-disease, physically inactive adults. The available evidence suggests potential for the greatest benefit to be seen in older populations and with higher intensity aerobic exercise.

Exercise Training Attenuates the Dysregulated Expression of Adipokines and Oxidative Stress in White Adipose Tissue

Obesity-induced inflammatory changes in white adipose tissue (WAT), which caused dysregulated expression of inflammation-related adipokines involving tumor necrosis factor-α and monocyte chemoattractant protein-1, contribute to the development of insulin resistance. Moreover, current literature reports state that WAT generates reactive oxygen species (ROS), and the enhanced production of ROS in obese WAT has been closely associated with the dysregulated expression of adipokines in WAT. Therefore, the reduction in excess WAT and oxidative stress that results from obesity is thought to be one of the important strategies in preventing and improving lifestyle-related diseases. Exercise training (TR) not only brings about a decrease in WAT mass but also attenuates obesity-induced dysregulated expression of the adipokines in WAT. Furthermore, some reports indicate that TR affects the generation of oxidative stress in WAT. This review outlines the impact of TR on the expression of inflammation-related adipokines and oxidative stress in WAT.

Influence to high-intensity intermittent and moderate-intensity continuous exercise on indices of cardio-inflammatory health in men

The aim of this study was to evaluate the influence to acute exercises performed in different intensities with volume equalized (5 km) on indices of cardio-inflammatory health. Twelve physically active male subjects (age, 23.22±5.47 years; height, 174.75±5.80 m; weight, 75.13±6.61 kg; maximal oxygen uptake, 52.92 mL/kg/min), after determination of peak oxygen uptake (VO_2Peak) and the speed associated with VO_2Peak (sVO_2Peak), completed two randomly experimental trials: high-intensity intermittent exercise (HIIE: 1:1 at 100% sVO_2Peak) and moderate-intensity continuous exercise (MICE: 70% sVO_2Peak). Brain-derived neurotrophic factor (BDNF), adiponectin and plasminogen inhibitor-1 (PAI-1) data were analyzed pre, immediately, and 60 min after the exercise session. Statistical analysis comparisons between moments and between HIIE and MICE were performed using a mixed model and statistical and significance was set at <5%. PAI-1 presented an effect for time from pre to immediately after exercise moment (P<0.018) and from immediately to 60 min after exercise moment (P<0.001) only in MICE. BDNF presented an effect for time from pre to immediately after exercise to HIIE (P<0.022) and from immediately to 60 min after exercise to MICE (P<0.034). HIIE promotes BDNF increase and that there is negative correlation between PAI-1 concentrations and BDNF in both protocols in healthy sportsmen, favoring an anti-atherogenic profile.

Addition of Exercise Increases Plasma Adiponectin and Release from Adipose Tissue

INTRODUCTION

Adiponectin is an adipose tissue-derived anti-inflammatory protein that is down-regulated in obesity. The effects of caloric restriction and exercise-induced weight loss on adiponectin are not clear.

PURPOSE

To determine whether addition of aerobic exercise training to caloric restriction has additive effects over caloric restriction alone on circulating adiponectin concentrations and adiponectin release from abdominal and gluteal adipose tissue.

METHODS

Overweight or obese (body mass index, 25-40 kg·m(-2); waist >88 cm) postmenopausal women were randomized to 20-wk caloric restriction with and without aerobic exercise (CR + EX, n = 48; and CR, n = 22). Blood samples were collected for measuring plasma adiponectin concentration, and abdominal and gluteal subcutaneous adipose tissue biopsies were performed in a subgroup to determine in vitro adiponectin release, before and after the interventions.

RESULTS

The interventions elicited similar amounts of weight loss (CR + EX, -11.3 ± 4.6 kg; CR,-11.2 ± 3.4 kg) and fat loss (CR + EX, -8.0 ± 3.5 kg; CR, -7.4 ± 2.7 kg). The two groups had differential changes in plasma adiponectin concentrations (for interaction, P = 0.014); CR + EX increased (6.9 ± 3.9 to 8.5 ± 4.9 μg·mL(-1); P = 0.0001), whereas CR did not alter (6.4 ± 4.4 to 6.5 ± 4.5 μg·mL(-1); P = 0.42) plasma adiponectin. Likewise, adiponectin release from abdominal and gluteal subcutaneous adipose tissue increased with CR + EX (P = 0.0076 and P = 0.089, respectively) but did not change with CR (P = 0.13 and P = 0.95, respectively).

CONCLUSION

Despite similar reductions in body weight and fat mass, the addition of aerobic exercise to caloric restriction increased plasma adiponectin concentrations, which may be partly explained by increased adiponectin release from abdominal and gluteal subcutaneous adipose tissue.

Evidence of a causal relationship between high serum adiponectin levels and increased cardiovascular mortality rate in patients with type 2 diabetes

BACKGROUND

Despite its beneficial role on insulin resistance and atherosclerosis, adiponectin has been repeatedly reported as an independent positive predictor of cardiovascular mortality.

METHODS

A Mendelian randomization approach was used, in order to evaluate whether such counterintuitive association recognizes a cause-effect relationship. To this purpose, single nucleotide polymorphism rs822354 in the ADIPOQ locus which has been previously associated with serum adiponectin at genome-wide level, was used as an instrument variable. Our investigation was carried out in the Gargano Heart Study-prospective design, comprising 356 patients with type 2 diabetes, in whom both total and high molecular weight (HMW) adiponectin were measured and cardiovascular mortality was recorded (mean follow-up = 5.4 ± 2.5 years; 58 events/1922 person-year).

RESULTS

The A allele of rs822354 was associated with both total and HMW adiponectin [β (SE) = 0.10 (0.042), p = 0.014 and 0.17 (0.06), p = 0.003; respectively]. In a Poisson model comprising age, sex, smoking habits, BMI, HbA1c, total cholesterol, HDL-cholesterol, triglycerides, insulin therapy and hypertension, both rs822354 (IRR = 1.94, 95 % CI 1.23-3.07; p = 0.005), as well as the genetic equivalent of total adiponectin change (IRR = 1.07, 95 % CI 1.02-1.12; p = 0.003) were significantly associated with cardiovascular mortality. The observed genetic effect was significantly greater than that exerted by the genetic equivalent change of serum adiponectin (p for IRR heterogeneity = 0.012). In the above-mentioned adjusted model, very similar results were obtained when HMW, rather than total, adiponectin was used as the exposure variable of interest.

CONCLUSIONS

Our data suggest that the paradoxical association between high serum adiponectin levels and increased cardiovascular mortality rate is based on a cause-effect relationship, thus pointing to an unexpected deleterious role of adiponectin action/metabolism on atherosclerotic processes.

Efeito do treinamento concorrente e destreinamento sobre o biomarcador anti-inflamatório e níveis de condicionamento físico em crianças obesas

OBJETIVO: Examinar o efeito de 12 semanas de (3 dias/sem) de treinamento concorrente e 4 semanas de destreinamento nas concentrações séricas de adiponectina e níveis de condicionamento físico em meninos obesos sem intervenção dietética. MÉTODOS: vinte e quatro meninos saudáveis, 11-13 anos de idade com índice de massa corporal > 28 participaram voluntariamente do estudo. Estes foram divididos em dois grupos, experimental (n= 12) e controle (n=12). RESULTADOS: Concentrações de adiponectina após 12 semanas tiveram declínio significativo em ambos os grupos em comparação com o nível basal (p < 0,05). VO2 pico, flexibilidade, força, endurance de abdominais e agilidade aumentaram significativamente no grupo experimental comparado com o grupo controle (p < 0.05). Foi evidenciado que após destreinamento de 4 semanas, a adiponectina sérica não se alterou significativamente no grupo experimental e que condicionamento físico benéfico foi gradualmente diminuído. CONCLUSÃO: Nossos resultados sugerem que os efeitos benéficos do exercício físico no condicionamento são temporários. Uma vez que o processo de adaptação é reversível, parece que as concentrações de adiponectina foram inevitavelmente afetadas pelas alterações morfológicas e hormonais que ocorreram durante a puberdade em meninos.

Changes in body weight, C-reactive protein, and total adiponectin in non-obese women after 12 months of a small-volume, home-based exercise program

OBJECTIVE

Our objective was to evaluate the effects of small-volume, home-based exercise combined with slight caloric restriction on the inflammatory markers C-reactive protein and adiponectin.

METHODS

In total, 54 women were randomly assigned to one of two groups for exercise intervention: the control or home-based exercise groups. Weight, waist and hip circumferences, and inflammatory markers were measured at baseline and after 6 and 12 months. Women allocated to the home-based exercise group received a booklet explaining the physical exercises to be practiced at home at least 3 times per week, 40 minutes per session, at low-to-moderate intensity. All participants received dietary counseling aimed at reducing caloric intake by 100-300 calories per day, with a normal distribution of macro-nutrients (26-28% of energy as fat). Clinicaltrials.gov: NCT01206413 RESULTS: The home-based exercise group showed a significantly greater reduction in weight and body mass index at six months, but no difference between groups was observed thereafter. With regard to the inflammatory markers, a greater but non-statistically significant reduction was found for C-reactive protein in the home-based exercise group at six months; however, this difference disappeared after adjusting for weight change. No differences in adiponectin were found at the 6- or 12-month follow-up.

CONCLUSION

Small-volume, home-based exercise did not promote changes in inflammatory markers independent of weight change.

The role of adiponectin in cancer: a review of current evidence

Excess body weight is associated not only with an increased risk of type 2 diabetes and cardiovascular disease (CVD) but also with various types of malignancies. Adiponectin, the most abundant protein secreted by adipose tissue, exhibits insulin-sensitizing, antiinflammatory, antiatherogenic, proapoptotic, and antiproliferative properties. Circulating adiponectin levels, which are determined predominantly by genetic factors, diet, physical activity, and abdominal adiposity, are decreased in patients with diabetes, CVD, and several obesity-associated cancers. Also, adiponectin levels are inversely associated with the risk of developing diabetes, CVD, and several malignancies later in life. Many cancer cell lines express adiponectin receptors, and adiponectin in vitro limits cell proliferation and induces apoptosis. Recent in vitro studies demonstrate the antiangiogenic and tumor growth-limiting properties of adiponectin. Studies in both animals and humans have investigated adiponectin and adiponectin receptor regulation and expression in several cancers. Current evidence supports a role of adiponectin as a novel risk factor and potential diagnostic and prognostic biomarker in cancer. In addition, either adiponectin per se or medications that increase adiponectin levels or up-regulate signaling pathways downstream of adiponectin may prove to be useful anticancer agents. This review presents the role of adiponectin in carcinogenesis and cancer progression and examines the pathophysiological mechanisms that underlie the association between adiponectin and malignancy in the context of a dysfunctional adipose tissue in obesity. Understanding of these mechanisms may be important for the development of preventive and therapeutic strategies against obesity-associated malignancies.