The Impact of Moderate-Intensity Continuous or High-Intensity Interval Training on Adipogenesis and Browning of Subcutaneous Adipose Tissue in Obese Male Rats

High-intensity interval training improves cardiomyocyte contractile function and myofilament sensitivity to intracellular Ca2+ in obese rats

High-intensity interval training (HIIT) has shown significant results in addressing adiposity and risk factors associated with obesity. However, there are no studies that investigate the effects of HIIT on contractility and intracellular Ca2+ handling. The purpose of this study was to explore the impact of HIIT on cardiomyocyte contractile function and intracellular Ca2+ handling in rats in which obesity was induced by a saturated high-fat diet (HFD). Male Wistar rats were initially randomized into a standard diet and a HFD group. The experimental protocol spanned 23 weeks, comprising the induction and maintenance of obesity (15 weeks) followed by HIIT treatment (8 weeks). Performance was assessed using the maximum oxygen consumption test (V ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{max}}}}$ ). Evaluation encompassed cardiac, adipose and skeletal muscle histology, as well as contractility and intracellular Ca2+ handling. HIIT resulted in a reduction in visceral area, an increase inV ̇ O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{max}}}}$ , and an augmentation of gastrocnemius fibre diameter in obese subjects. Additionally, HIIT led to a decrease in collagen fraction, an increase in percentage shortening, and a reduction in systolic Ca2+/percentage shortening and systolic Ca2+/maximum shortening rates. HIIT induces physiological cardiac remodelling, enhancing the contractile function of cardiomyocytes and improving myofilament sensitivity to Ca2+ in the context of obesity. This approach not only enhances cardiorespiratory and physical performance but also reduces visceral area and prevents interstitial fibrosis.

Years of endurance exercise training remodel abdominal subcutaneous adipose tissue in adults with overweight or obesity

Abnormalities in the structure and metabolic function of abdominal subcutaneous adipose tissue (aSAT) underlie many obesity-related health complications. Endurance exercise improves cardiometabolic health in adults with overweight or obesity, but the effects of endurance training on aSAT are unclear. We included male and female participants who were regular exercisers with overweight or obesity who exercised for >2 years, and cross-sectionally compared them with well-matched non-exercisers with overweight or obesity. Here we show aSAT from exercisers has a higher capillary density, lower Col6a abundance and fewer macrophages compared with non-exercisers. This is accompanied by a greater abundance of angiogenic, ribosomal, mitochondrial and lipogenic proteins. The abundance of phosphoproteins involved in protein translation, lipogenesis and direct regulation of transcripts is also greater in aSAT collected from exercisers. Exploratory ex vivo experiments demonstrate greater angiogenic capacity and higher lipid-storage capacity in samples cultured from aSAT collected from exercisers versus non-exercisers. Regular exercise may play a role in remodelling aSAT structure and proteomic profile in ways that may contribute to preserved cardiometabolic health.

Lactate coordinated with exercise promoted the browning of inguinal white adipose tissue

Lactate, an important exercise metabolite, induces white adipose tissue browning by upregulated uncoupling protein 1 (UCP1) expression. However, the function of lactate during browning of inguinal white adipose tissue (iWAT) caused by exercise is unclear. Here, we considered lactate as an exercise supplement and investigated the effects of chronic pre-exercise lactate administration on energy metabolism and adipose tissue browning. C57B/L6 male mice (5 weeks of age) were divided into six groups. We evaluated the changes in blood lactate levels in each group of mice after the intervention. Energy expenditure was measured after the intervention immediately by indirect calorimetry. The marker protein levels and gene expressions were determined by western-blot and quantitative real-time PCR. HIIT significantly decreased adipose tissue weight while increased energy expenditure and the expression of UCP1 in iWAT; however, these regulations were inhibited in the DCA+HIIT group. Compared with the MICT and LAC groups, long-term lactate injection before MICT led to lower WAT weight to body weight ratios and higher energy expenditure in mice. Furthermore, the marker genes of browning in iWAT, such as Ucp1 and Pparγ, were significantly increased in the LAC+MICT group than in the other groups, and the expression of monocarboxylate transporter-1 (Mct1) mRNA was also significantly increased. Lactate was involved in exercise-mediated browning of iWAT, and its mechanism might be the increased of lactate transport through MCT1 or PPARγ upregulation induced by exercise. These findings suggest exogenous lactate may be a new exercise supplement to regulate metabolism.

Effect of high-intensity interval training on self-care and anxiety-like behaviors in naive rats

Self-care behavior covers individual's health, life and well-being to maintain the necessary activities. The aim of this study is to examine the self-care and possible anxiolytic effects of high-intensity interval exercise (HIIT). Eight-week-old Wistar Albino male rats were divided into Control (n = 8), and Exercise (n = 8). Rat exercised for 38 min a day, 5 days a week, for 8 weeks The animals were then subjected to open field test and splash test, and the behaviors were video recorded. Student t test and Shapiro-Wilk test were used as statistical tests. In the exercise group, spray-induced grooming behavior increased significantly in terms of duration and frequency (p < 0.05), but no significant difference was observed in the latency of grooming (p > 0.05). In the open-field test, the total distance traveled, which is a locomotor activity parameter, did not change between the groups. Anxiolytic-like behaviors such as total rearing behavior, unsupported rearing, central time, and central region entries increased remarkably in the exercise group vs. control (p < 0.0001). Freezing as an anxiogenic behavior decreased in the exercise group positively (p < 0.0001). Intermittent high-intensity exercise improved and increased self-care behaviors. Further, the present study shows that HIIT has beneficial effects on different aspects of behaviors such as exploratory behaviors, increasing anxiolytic behaviors, and reducing anxiogenic behavior. The present study is a preclinical study that will pave the way for new studies.

Is Physical Activity an Efficient Strategy to Control the Adverse Effects of Persistent Organic Pollutants in the Context of Obesity? A Narrative Review

Obesity affects nearly 660 million adults worldwide and is known for its many comorbidities. Although the phenomenon of obesity is not fully understood, science regularly reveals new determinants of this pathology. Among them, persistent organic pollutants (POPs) have been recently highlighted. Mainly lipophilic, POPs are normally stored in adipose tissue and can lead to adverse metabolic effects when released into the bloodstream. The main objective of this narrative review is to discuss the different pathways by which physical activity may counteract POPs' adverse effects. The research that we carried out seems to indicate that physical activity could positively influence several pathways negatively influenced by POPs, such as insulin resistance, inflammation, lipid accumulation, adipogenesis, and gut microbiota dysbiosis, that are associated with the development of obesity. This review also indicates how, through the controlled mobilization of POPs, physical activity could be a valuable approach to reduce the concentration of POPs in the bloodstream. These findings suggest that physical activity should be used to counteract the adverse effects of POPs. However, future studies should accurately assess its impact in specific situations such as bariatric surgery, where weight loss promotes POPs' blood release.

Impacts of an 8-week regimen of aged garlic extract and aerobic exercise on the levels of Fetuin-A and inflammatory markers in the liver and visceral fat tissue of obese male rats

BACKGROUND & AIMS

Obesity-induced chronic low-grade systemic inflammation is linked to the development of numerous diseases. Fetuin-A is known to affect inflammation and insulin resistance in obesity conditions. Free fatty acid (FFA)-induced proinflammatory cytokine expression in adipocytes occurs only in the presence of both Fetuin-A and toll-like receptor 4 (TLR4) and removing either of them prevented FFA-induced insulin resistance. Aged garlic extract (AGE) and exercise training have anti-inflammatory effects; however, the impact of AGE on Fetuin-A is unknown. We examined the effects of AGE with or without aerobic training (AT) on Fetuin-A and inflammatory markers.

METHODS

Forty healthy male Sprague Dawley rats were randomly assigned to normal diet (ND) (n = 8) or high-fat diet (HFD) groups (n = 32) and fed for 9 weeks. After 9 weeks ND group continued normal diet, and the HFD group was randomly assigned to the HFD, HFD + AGE (600 mg/kg, once daily), HFD + AT (5 days/week), and HFD + AGE + AT groups that were continued for 8 weeks (n = 8). The significance of differences among groups was assessed using one-way analysis of variance followed by the post-hoc Tukey test. Statistically significant differences were considered for p < 0.05.

RESULTS

AGE, AT, and AGE + AT significantly decreased body weight, plasma Fetuin-A, HOMA-IR, mRNA and protein levels of Fetuin-A and NFƙB in the liver and mRNA and Protein levels of Fetuin-A, TLR4 and NFƙB in visceral adipose tissue (VAT) compared to HFD. However, only AGE + AT significantly decreased TLR4 protein levels in the liver.

CONCLUSION

Although AT and AGE reduce Fetuin-A and inflammatory markers, a combination of the two may be more effective at lowering inflammation.

Exercise-regulated white adipocyte differentitation: An insight into its role and mechanism

White adipocytes play a key role in the regulation of fat mass amount and energy balance. An appropriate level of white adipocyte differentiation is important for maintaining metabolic homeostasis. Exercise, an important way to improve metabolic health, can regulate white adipocyte differentiation. In this review, the effect of exercise on the differentiation of white adipocytes is summarized. Exercise could regulate adipocyte differentiation in multiple ways, such as exerkines, metabolites, microRNAs, and so on. The potential mechanism underlying the role of exercise in adipocyte differentiation is also reviewed and discussed. In-depth investigation of the role and mechanism of exercise in white adipocyte differentiation would provide new insights into exercise-mediated improvement of metabolism and facilitate the application of exercise-based strategy against obesity.

Contribution of High-Intensity Interval Exercise in the Fasted State to Fat Browning: Potential Roles of Lactate and β-Hydroxybutyrate

PURPOSE

Fat browning contributes to energy consumption and may have metabolic benefits against obesity; however, the potential roles of lactate and β-hydroxybutyrate (β-HB) in fat browning remain unclear. We investigated the roles of a single bout of aerobic exercise that increases lactate and β-HB levels in the fasted state on the regulation of fat browning in rats and humans.

METHODS

Male Sprague-Dawley rats were exposed to 24-h fasting and/or a single bout moderate-intensity aerobic exercise (40 min): sedentary (CON), exercise (ND-EX), fasting (FAST), and exercise + fasting (F-EX). Adult men ( n = 13) were randomly assigned into control with food intake (CON), exercise with intensity at onset of blood lactate accumulation in the fasted state (F-OBLA), and high-intensity interval exercise in the fasted state (F-HIIE) until each participant expended 350 kcal of energy. For evaluating the effects of exercise intensity in rats, we conducted another set of animal experiment, including groups of sedentary fed control, fasting control, and exercise with moderate-intensity or HIIE for 40 min after a 24-h fasting.

RESULTS

Regardless of fasting, single bout of exercise increases the concentration of lactate and β-HB in rats, but the exercise in the fasted state increases the β-HB level more significantly in rats and humans. F-EX-activated fat browning (AMPK-SirT1-PGC1α pathway and PRDM16) and thermogenic factor (UCP1) in white fat of rats. In rats and humans, exercise in the fasted state increased the blood levels of fat browning-related adipomyokines. In particular, compared with F-OBLA, F-HIIE more efficiently increases free fatty acid as well as blood levels of fat browning adipomyokines in humans, which was correlated with blood levels of lactate and β-HB. In rats that performed exercise with different intensity, the higher plasma lactate and β-HB levels, and higher expression of p-AMPK, UCP1, and PRDM16 in white adipose tissue of HIIE group than those of moderate-intensity group, were observed.

CONCLUSIONS

A single bout of aerobic exercise in the fasted state significantly induced fat browning-related pathways, free fatty acid, and adipomyokines, particularly F-HIIE in human. Although further evidence for supporting our results is required in humans, aerobic exercise in the fasted state with high intensity that increase lactate and β-HB may be a modality of fat browning.

Differential remodeling of subcutaneous white and interscapular brown adipose tissue by long-term exercise training in aged obese female mice

Obesity exacerbates aging-induced adipose tissue dysfunction. This study aimed to investigate the effects of long-term exercise on inguinal white adipose tissue (iWAT) and interscapular brown adipose tissue (iBAT) of aged obese mice. Two-month-old female mice received a high-fat diet for 4 months. Then, six-month-old diet-induced obese animals were allocated to sedentarism (DIO) or to a long-term treadmill training (DIOEX) up to 18 months of age. In exercised mice, iWAT depot revealed more adaptability, with an increase in the expression of fatty acid oxidation genes (Cpt1a, Acox1), and an amelioration of the inflammatory status, with a favorable modulation of pro/antiinflammatory genes and lower macrophage infiltration. Additionally, iWAT of trained animals showed an increment in the expression of mitochondrial biogenesis (Pgc1a, Tfam, Nrf1), thermogenesis (Ucp1), and beige adipocytes genes (Cd137, Tbx1). In contrast, iBAT of aged obese mice was less responsive to exercise. Indeed, although an increase in functional brown adipocytes genes and proteins (Pgc1a, Prdm16 and UCP1) was observed, few changes were found on inflammation-related and fatty acid metabolism genes. The remodeling of iWAT and iBAT depots occurred along with an improvement in the HOMA index for insulin resistance and in glucose tolerance. In conclusion, long-term exercise effectively prevented the loss of iWAT and iBAT thermogenic properties during aging and obesity. In iWAT, the long-term exercise program also reduced the inflammatory status and stimulated a fat-oxidative gene profile. These exercise-induced adipose tissue adaptations could contribute to the beneficial effects on glucose homeostasis in aged obese mice.

Swimming in cold water upregulates genes involved in thermogenesis and the browning of white adipose tissues

The purpose of this study was to investigate whether there is an interacting effect of six weeks of swimming in cold water on the gene expression of browning markers in adipose tissue in rodents. Twenty male Wistar rats were randomly divided into four groups: Control (C, 25 °C), Cold Exposure (CE, 4 °C), Swimming in tepid Water (STW, 30 °C), and Swimming in Cold Water (SCW, 15 °C). The swimming included 2-3 min intervals, 1 min rest, until exhaustion, three days a week for six weeks, with 3 to 6% of bodyweight overload. Rats from CE were exposed to cold for 2 h per day, five days per week. After the experimental protocol, interscapular brown (BAT) and inguinal subcutaneous white (WAT) fat tissues were excised, weighed, and processed for beiging and mitochondrial biogenesis markers gene expression. The experimental protocols resulted in an apparent increase in the number of brown adipocytes (per mm²) in the adipose deposits compared to the C group; substantial changes were observed in the SCW group. Compared to other groups, cold exposure alone increased significantly serum norepinephrine, and also β₂-adrenergic receptor expression was upregulated in the adipocytes compared to the C group. The STW group increased the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) coactivator-1 alpha (PGC-1α), β₂-adrenergic receptor, and CCAAT/enhancer-binding proteins-α(c/EBP-α) in WAT in comparison with the C group(p < 0.05). In both adipocytes, the SCW intervention significantly upregulated the expression of PGC-1α, PPAR-γ, and c/EBP-α genes in comparison with the C and CE groups. In addition, the expression of TFAM and UCP1 was upregulated substantially in the SCW group compared to other groups. Our data demonstrate that swim training and cold exposure present additive effects in the expression of genes involved in the beiging process and mitochondrial biogenesis markers in BAT and WAT. In addition, it seems that the upregulation of these genes is related to the activation of β₂-adrenergic receptors.

The Importance of Animal Models in Biomedical Research: Current Insights and Applications

Animal research is considered a key element in advance of biomedical science. Although its use is controversial and raises ethical challenges, the contribution of animal models in medicine is essential for understanding the physiopathology and novel treatment alternatives for several animal and human diseases. Current pandemics’ pathology, such as the 2019 Coronavirus disease, has been studied in primate, rodent, and porcine models to recognize infection routes and develop therapeutic protocols. Worldwide issues such as diabetes, obesity, neurological disorders, pain, rehabilitation medicine, and surgical techniques require studying the process in different animal species before testing them on humans. Due to their relevance, this article aims to discuss the importance of animal models in diverse lines of biomedical research by analyzing the contributions of the various species utilized in science over the past five years about key topics concerning human and animal health.

Comparison of moderate-intensity continuous training and high-intensity interval training effects on the Ido1-KYN-Ahr axis in the heart tissue of rats with occlusion of the left anterior descending artery

Myocardial infarction (MI) affects many molecular pathways in heart cells, including the Ido1-KYN-Ahr axis. This pathway has recently been introduced as a valuable therapeutic target in infarction. We examined the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on the axis in the heart tissue of male Wistar rats with occluded left anterior descending (OLAD). Thirty rats (age 10-12 weeks, mean weight 275 ± 25 g) were divided into five groups with 6 animals: Control (Ct) group, MICT group, rats with OLAD as MI group, rats with OLAD treated with MICT (MIMCT group) and rats with OLAD treated with HIIT (MIHIIT group). Rats performed the training protocols for 8 weeks, 5 days a week. HIIT included 7 sets of 4 min running with an intensity of 85-90% VO₂max and 3 min of recovery activation between sets. MICT included continuous running at the same distance as HIIT with an intensity of 50-60% VO₂max for 50 min. The expressions of Ahr, Cyp1a1, and Ido1 were assayed by real-time PCR. Malondialdehyde (MDA) and Kynurenine levels, and AHR, CYP1A1, and IDO1 proteins were detected using ELISA. Data were analyzed using the ANOVA and MANOVA tests. Compared to the CT group, MI caused an increase in all studied factors, but only statistically significant (P < 0.05) for MDA and IDO1. With a greater effect of HIIT, both protocols significantly lowered the proteins expressions in the MIHIIT and MIMCT groups, compared with the MI group (P < 0.001). In healthy rats, only AHR protein significantly decreased in the MICT group compared to the Ct group (P < 0.05). HIIT and MICT protocols significantly reduced the gene and protein expression of Cyp1a1 (P < 0.05) and Ido1 (P < 0.01), and HIIT had a greater effect. In conclusion, both protocols were effective at reducing the levels of Ido1-Kyn-Ahr axis components and oxidative stress in the infarcted heart tissue and HIIT had a higher significant effect.

Exercise intervention mitigates zebrafish age-related sarcopenia via alleviating mitochondrial dysfunction

Sarcopenia is a common disorder that leads to a progressive decrease in skeletal muscle function in elderly people. Exercise effectively prevents or delays the onset and progression of sarcopenia. However, the molecular mechanisms underlying how exercise intervention improves skeletal muscle atrophy remain unclear. In this study, we found that 21-month-old zebrafish had a decreased swimming ability, reduced muscle fibre cross-sectional area, unbalanced protein synthesis, and degradation, increased oxidative stress, and mitochondrial dysfunction, which suggests zebrafish are a valuable model for sarcopenia. Eight weeks of exercise intervention attenuated these pathological changes in sarcopenia zebrafish. Moreover, the effects of exercise on mitochondrial dysfunction were associated with the activation of the AMPK/SIRT1/PGC-1α axis and 15-PGDH downregulation. Our results reveal potential therapeutic targets and indicators to treat age-related sarcopenia using exercise intervention.

The effects of camelina sativa oil and high-intensity interval training on liver function and metabolic outcomes in male type 2 diabetic rats

Objectives

The purpose of this study was to evaluate the independent and combined effects of camelina sativa oil and high-intensity interval training (HIIT) on liver function, and metabolic outcomes in streptozotocin-induced diabetic rats.

Methods

Forty male Wistar rats were randomly assigned to five equal groups (8 per group): Normal control (NC), diabetic control (DC), diabetic + camelina sativa oil (300 mg/kg by oral gavage per day; D + CSO), diabetic + HIIT (running on a treadmill 5 days/week for 8 weeks; D + HIIT), diabetic + camelina sativa oil + HIIT (D + CSO +  HIIT).

Results

In all three intervention groups (D + CSO, D + HIIT, and D + CSO + HIIT) compared to the DC, hepatic TNF-α, MDA, and histopathology markers, decreased and hepatic PGC-1α, and PPAR-γ increased (p < 0.05). However, the effect of D + CSO was greater than D + HIIT alone. Hepatic TG decreased significantly in D + HIIT and D + CSO + HIIT compared to other groups (p < 0.001). Fasting plasma glucose in all three intervention groups (D + CSO, D + HIIT, and D + CSO + HIIT) and HOMA-IR in D + CSO and D + CSO + HIIT were decreased compared to DC (p < 0.001). Only hepatic TAC and fasting plasma insulin remained unaffected in the three diabetic groups (p < 0.001). Overall, D + CSO + HIIT had the largest effect on all outcomes.

Conclusions

At the doses and treatment duration used in the current study, combination of CSO and HIIT was beneficial for reducing liver function and metabolic outcomes other than CSO and HIIT alone.

Mitochondrial Stress in Metabolic Inflammation: Modest Benefits and Full Losses

Energy intake and metabolic balance are the pillars of health preservation. Overnutrition causes nonspecific, persistently low inflammatory state known as metabolic inflammation. This condition contributes to the pathophysiology of various metabolic disorders, such as atherosclerosis, obesity, diabetes mellitus, and metabolic syndrome. The mitochondria maintain the balance of energy metabolism. Excessive energy stress can lead to mitochondrial dysfunction, which promotes metabolic inflammation. The inflammatory environment further impairs mitochondrial function. Accordingly, excellent organism design keeps the body metabolically healthy in the context of mitochondrial dysfunction, and moderate mitochondrial stress can have a beneficial effect. This review summarises the research progress on the multifaceted characterisation of mitochondrial dysfunction and its role in metabolic inflammation.

Effects of two workload-matched high intensity interval training protocols on regulatory factors associated with mitochondrial biogenesis in the soleus muscle of diabetic rats

Aims: High intensity interval training (HIIT) improves mitochondrial characteristics. This study compared the impact of two workload-matched high intensity interval training (HIIT) protocols with different work:recovery ratios on regulatory factors related to mitochondrial biogenesis in the soleus muscle of diabetic rats. Materials and methods: Twenty-four Wistar rats were randomly divided into four equal-sized groups: non-diabetic control, diabetic control (DC), diabetic with long recovery exercise [4-5 × 2-min running at 80%-90% of the maximum speed reached with 2-min of recovery at 40% of the maximum speed reached (DHIIT1:1)], and diabetic with short recovery exercise (5-6 × 2-min running at 80%-90% of the maximum speed reached with 1-min of recovery at 30% of the maximum speed reached [DHIIT2:1]). Both HIIT protocols were completed five times/week for 4 weeks while maintaining equal running distances in each session. Results: Gene and protein expressions of PGC-1α, p53, and citrate synthase of the muscles increased significantly following DHIIT1:1 and DHIIT2:1 compared to DC (p ˂ 0.05). Most parameters, except for PGC-1α protein (p = 0.597), were significantly higher in DHIIT2:1 than in DHIIT1:1 (p ˂ 0.05). Both DHIIT groups showed significant increases in maximum speed with larger increases in DHIIT2:1 compared with DHIIT1:1. Conclusion: Our findings indicate that both HIIT protocols can potently up-regulate gene and protein expression of PGC-1α, p53, and CS. However, DHIIT2:1 has superior effects compared with DHIIT1:1 in improving mitochondrial adaptive responses in diabetic rats.

Skeletal Muscle Mitochondrial and Perilipin Content in a Cohort of Obese Subjects Undergoing Moderate and High Intensity Training

Obesity is a complex condition characterized by abnormal and excessive fat accumulation, resulting in an increased risk for severe health problems. Skeletal muscles play a major role in movement and fat catabolism, but the insulin resistance that comes with obesity makes it difficult to fulfill these tasks. In this study, we analyse two types of training protocols, moderate intensity continuous training (MICT) versus high intensity interval training (HIIT), in a cohort of obese subjects to establish which muscle adaptations favour fat consumption in response to exercise. Mitochondria play a role in fat oxidation. We found protein upregulation of mitochondrial biomarkers, TOMM20 and Cox-4, in HIIT but not in MICT, without detecting any shifts in fibre composition phenotype of the vastus lateralis in both training groups. Interestingly, both MICT and HIIT protocols showed increased protein levels of perilipin PLIN2, which is involved in the delivery and consumption of fats. HIIT also augmented perilipin PLIN5. Perilipins are involved in fat storage in skeletal muscles and their upregulation, along with the analysis of circulatory lipid profiles reported in the present study, suggest important adaptations induced by the two types of training protocols that favour fat consumption and weight loss in obese subjects.

The effectiveness of high-intensity interval training on body composition of rodent models of obesity: A systematic review and meta-analysis

The present systematic review was compiled to analyze the effectiveness of High-intensity interval training (HIIT) protocols on the body composition of rodents with obesity. Databases were searched until February 2021 for experimental trials in rodents with a minimum duration of four weeks of HIIT and endpoints associated with obesity. The data were analyzed by meta-analysis performed for comparisons of body composition. Sensitivity analysis was performed to investigate the consistency of individual researches. Of all of the 524 studies found, only 14 were included. The analysis showed a significant reduction in body weight ([CI 95%: -8.35; -1.98] P ≤ 0.01), adiposity index ([IC 95%: -1.04; -0.80] P ≤ 0.01), and fat pads ([IC 95%: -0.59; -0.06] P ≤ 0.01). HIIT performed on treadmill or water was effective to reduce body weight (P < 0.05). In conclusion, HIIT attenuated both body weight and adiposity induced either by HFD (high-fat diet) or by GOM (genetic obese model), thereby inducing positive changes in body composition.

A promising drug combination of mangiferin and glycyrrhizic acid ameliorates disease severity of rheumatoid arthritis by reversing the disturbance of thermogenesis and energy metabolism

BACKGROUND

Activation of immune system in rheumatoid arthritis (RA) consumes amount of energy, and the energy metabolic signals may be a potential target for RA therapy. Baihu-Guizhi decoction (BHGZD) achieves satisfactory therapeutic effects in RA in clinics by recovering the adjacent articular cartilage and bone destruction, and abnormal articular temperature. However, its pharmacological material basis and molecular mechanisms have not been fully elucidated.

PURPOSE

This study focused on exploring the potential acting mechanism of BHGZD against RA, and identifying its main bioactive compounds (BACs) of the combination of mangiferin and glycyrrhizic acid.

METHODS

Key putative targets of BHGZD acting on adjuvant-induced arthritis (AIA)-M rats were screened by the transcriptomic profiling of the whole blood cells and synovium tissues collected from rats in normal control, AIA-M model and AIA-M-BHGZD treatment groups. Then, BACs of BHGZD against RA were identified using Ultra Performance Liquid Chromatography-Mass spectrum/Mass spectrum, molecular docking, surface plasmon resonance and pharmacokinetic analysis. In vivo experiments based on AIA-M rats and in vitro experiments based on 3T3-L1 preadipocytes were performed to verify the pharmacological effects of BACs against RA and the corresponding mechanisms.

RESULTS

PKA-ADCY5-PPARγ-PGC 1α-UCP1-PRDM16 signal axis was demonstrated to be the candidate targets of BHGZD against RA and was involved in maintaining the balance of thermogenesis and energy metabolism, according to the transcriptional regulatory network analysis based on "herbs-putative targets-disease interaction network". Then, mangiferin from Rhizoma Anemarrhenae and glycyrrhizic acid from Radix Glycytthizae were identified as the main BACs of BHGZD against RA due to their highly accumulation in the blood in vivo, strong binding affinities with the two candidate targets of BHGZD against RA-ADCY5 and PPARγ, as well as the in vivo and in vitro strong regulation effects on energy metabolism disturbance.

CONCLUSIONS

These findings offer evidence that the combination of mangiferin and glycyrrhizic acid from BHGZD may be a promising candidate drug for RA therapy, and also provide an important reference for the development and modernization of traditional Chinese formulae.

Irisin is an Effector Molecule in Exercise Rehabilitation Following Myocardial Infarction (Review)

Background: Regular exercise is an effective non-pharmacological therapy for treatment and prevention of cardiovascular disease (CVD). The therapeutic benefits of exercise are mediated partly through improved vascular and increase in metabolic health. Release of exercise-responsive myokines, including irisin, is associated with beneficial effects of exercise in CVD patients.

Observations: The present review provides an overview of the role of exercise in cardiac rehabilitation of patients with myocardial infarction (MI). Further, the role of irisin as a motion-responsive molecule in improving vascular and metabolic health is explored. Possible mechanism of cardioprotective effect of irisin-mediated exercise on myocardial infarction are also summarized in this review.

Conclusion and significance of the review: Irisin is associated with reduced inflammation, antioxidant properties, and anti-apoptotic effect, implying that it is a potential key mediator of the beneficial effects of exercise on vascular and metabolic health. The findings show that irisin is a promising therapeutic target for treatment of patients with cardiovascular disease, particularly post-MI. Further research should be conducted to elucidate the potential mechanisms of cardioprotective effects of irisin and explored whether irisin induced by exercise exerts rehabilitation effects post-MI.

Exercise-Induced Browning of White Adipose Tissue and Improving Skeletal Muscle Insulin Sensitivity in Obese/Non-obese Growing Mice: Do Not Neglect Exosomal miR-27a

Exercise is considered as a favorable measure to prevent and treat childhood obesity. However, the underlying mechanisms of exercise-induced beneficial effects and the difference between obese and non-obese individuals are largely unclear. Recently, miR-27a is recognized as a central upstream regulator of proliferator-activated receptor γ (PPAR-γ) in contributing to various physiological and pathological processes. This study aims to explore the possible cause of exercise affecting white adipose tissue (WAT) browning and reversing skeletal muscle insulin resistance in obese/non-obese immature bodies. For simulating the process of childhood obesity, juvenile mice were fed with a basal diet or high-fat diet (HFD) and took 1 or 2 h swimming exercise simultaneously for 10 weeks. The obese animal model was induced by the HFD. We found that exercise hindered HFD-induced body fat development in growing mice. Exercise modified glucolipid metabolism parameters differently in the obese/non-obese groups, and the changes of the 2 h exercise mice were not consistent with the 1 h exercise mice. The level of serum exosomal miR-27a in the non-exercise obese group was increased obviously, which was reduced in the exercise obese groups. Results from bioinformatics analysis and dual-luciferase reporter assay showed that miR-27a targeted PPAR-γ. Exercise stimulated WAT browning; however, the response of obese WAT lagged behind normal WAT. In the HFD-fed mice, 2 h exercise activated the IRS-1/Akt/GLUT-4 signaling pathway in the skeletal muscles. In summary, our findings confirmed that exercise-induced beneficial effects are associated with exercise duration, and the response of obese and non-obese bodies is different. Exosomal miR-27a might be a crucial node for the process of exercise-induced browning of WAT and improving skeletal muscle insulin sensitivity.

Comparison of visceral fat lipolysis adaptation to high-intensity interval training in obesity-prone and obesity-resistant rats

BACKGROUND/OBJECTIVES

Visceral obesity is one of the key features of metabolic syndrome. High-intensity interval training (HIIT) could effectively reduce visceral fat, but its effects show strong heterogeneity in populations with different degrees of obesity. The mechanism may be related to the differential adaptation to training between obesity phenotypes, namely obesity prone (OP) and obesity resistant (OR). The aim of the present study was to compare adaptive changes of visceral adipose lipolysis adaptation to HIIT between OP and OR animals and further explore the upstream pathway.

METHODS

OP and OR Sprague Dawley rats were established after feeding a high-fat diet for 6 weeks; they were then divided into HIIT (H-OP and H-OR) and control (C-OP and C-OR) groups. After 12 weeks of HIIT or a sedentary lifestyle, animals were fasted for 12 h and then sacrificed for histology as well as gene and protein analysis. Visceral adipocytes were isolated without fasting for catecholamine stimulation and β3-adrenergic receptor (β3-AR) blockade in vitro to evaluate the role of upstream pathways.

RESULTS

After training, there were no differences in weight loss or food intake between OP and OR rats (P > 0.05). However, the visceral fat mass, adipocyte volume, serum triglycerides and liver lipids of OP rats decreased by more than those of OR rats (P < 0.05). Meanwhile, the cell lipolytic capacity and the increase in the expression of β3-AR were higher in the OP compared with OR groups (P < 0.05). Although training did not increase sympathetic nervous system activity (P > 0.05), the cell sensitivity to catecholamine increased significantly in the OP compared with OR groups (P < 0.05). Following blocking β3-AR, the increased sensitivity disappeared.

CONCLUSION

With HIIT, OP rats lost more visceral fat than OR rats, which was related to stronger adaptive changes in lipolysis. Increased β3-AR expression mediated this adaptation.

Strength training alters the tissue fatty acids profile and slightly improves the thermogenic pathway in the adipose tissue of obese mice

Obesity is a disease characterized by the exacerbated increase of adipose tissue. A possible way to decrease the harmful effects of excessive adipose tissue is to increase the thermogenesis process, to the greater energy expenditure generated by the increase in heat in the body. In adipose tissue, the thermogenesis process is the result of an increase in mitochondrial work, having as substrate H⁺ ions, and which is related to the increased activity of UCP1. Evidence shows that stress is responsible for increasing the greater induction of UCP1 expression via β-adrenergic receptors. It is known that physical exercise is an important implement for sympathetic stimulation promoting communication between norepinephrine/epinephrine with membrane receptors. Thus, the present study investigates the influence of short-term strength training (STST) on fatty acid composition, lipolysis, lipogenesis, and browning processes in the subcutaneous adipose tissue (sWAT) of obese mice. For this, Swiss mice were divided into three groups: lean control, obesity sedentary, and obese strength training (OBexT). Obese animals were fed a high-fat diet for 14 weeks. Trained obese animals were submitted to 7 days of strength exercise. It was demonstrated that STST sessions were able to reduce fasting glycemia. In the sWAT, the STST was able to decrease the levels of the long-chain fatty acids profile, saturated fatty acid, and palmitic fatty acid (C16:0). Moreover, it was showed that STST did not increase protein levels responsible for lipolysis, the ATGL, ABHD5, pPLIN1, and pHSL. On the other hand, the exercise protocol decreased the expression of the lipogenic enzyme SCD1. Finally, our study demonstrated that the STST increased browning process-related genes such as PGC-1α, PRDM16, and UCP1 in the sWAT. Interestingly, all these biomolecular mechanisms have been observed independently of changes in body weight. Therefore, it is concluded that short-term strength exercise can be an effective strategy to initiate morphological changes in sWAT.

Dietary Intervention Associated With Moderate-Intensity Continuous Training Leads to Changes in the Inflammatory Profile in Visceral Adipose Tissue but Not in Skeletal Muscle in Diet-Induced Obese Rats

This study aimed to determine the concentrations of inflammatory markers in visceral adipose tissue (VAT) and skeletal muscle, and changes in body mass and adipocyte size in diet-induced obese rats after moderate-intensity continuous training (MICT) and/or dietary intervention. After 8 weeks of obesity induction through a high-fat diet (HFD) consumption, twenty diet-induced obese male Wistar rats were divided into four groups as follows: (i) control rats fed with HFD (HFD-SED), (ii) obese rats fed with HFD and submitted to MICT (HFD-MICT), (iii) obese rats that were submitted to a nutritional intervention by switching HFD to chow diet (CD-SED), and (iv) obese rats that were submitted to MICT and nutritional intervention (CD-MICT). All the animals in the training groups were submitted to MICT, with an intensity of 50–85% of Vmax, 60 min/day, 3 days/week for 8 weeks. Gastrocnemius muscle (GAST) and mesenteric adipose tissue (mWAT) were collected to quantify tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and IL-10 using ELISA. The body mass was recorded before and after the experimental protocols, and the adipocyte morphology was assessed using histological analysis. The results showed that HFD-SED had higher body mass, higher concentrations of inflammatory markers in mWAT, and higher increase in adipocyte size. The CD-SED and CD-MICT groups presented with reduced body mass, relative weight of mWAT, and adipocyte size. Moreover, the inflammatory markers in mWAT were reduced after dietary intervention (TNF-α), MICT (IL-10 and TNF-α), or both interventions combined (IL-6 and TNF-α). In contrast, there was no reduction in GAST-relative weight or concentrations of inflammatory markers for any treatment. Finally, we concluded that 8 weeks of dietary intervention alone and combined with MICT were effective in reducing some of the deleterious effects caused by obesity.

Insulin and cancer: a tangled web

For a century, since the pioneering work of Otto Warburg, the interwoven relationship between metabolism and cancer has been appreciated. More recently, with obesity rates rising in the U.S. and worldwide, epidemiologic evidence has supported a link between obesity and cancer. A substantial body of work seeks to mechanistically unpack the association between obesity, altered metabolism, and cancer. Without question, these relationships are multifactorial and cannot be distilled to a single obesity- and metabolism-altering hormone, substrate, or factor. However, it is important to understand the hormone-specific associations between metabolism and cancer. Here, we review the links between obesity, metabolic dysregulation, insulin, and cancer, with an emphasis on current investigational metabolic adjuncts to standard-of-care cancer treatment.

Distinct Effects of High-Fat and High-Phosphate Diet on Glucose Metabolism and the Response to Voluntary Exercise in Male Mice

The prevalence of metabolic diseases is rapidly increasing and a principal contributor to this is diet, including increased consumption of energy-rich foods and foods with added phosphates. Exercise is an effective therapeutic approach to combat metabolic disease. While exercise is effective to combat the detrimental effects of a high-fat diet on metabolic health, the effects of exercise on a high-phosphate diet have not been thoroughly investigated. Here, we investigated the effects of a high-fat or high-phosphate diet in the presence or absence of voluntary exercise on metabolic function in male mice. To do this, mice were fed a low-fat, normal-phosphate diet (LFPD), a high-phosphate diet (HPD) or a high-fat diet (HFD) for 6 weeks and then subdivided into either sedentary or exercised (housed with running wheels) for an additional 8 weeks. An HFD severely impaired metabolic function in mice, increasing total fat mass and worsening whole-body glucose tolerance, while HPD did not induce any notable effects on glucose metabolism. Exercise reverted most of the detrimental metabolic adaptations induced by HFD, decreasing total fat mass and restoring whole-body glucose tolerance and insulin sensitivity. Interestingly, voluntary exercise had a similar effect on LFPD and HPD mice. These data suggest that a high-phosphate diet does not significantly impair glucose metabolism in sedentary or voluntary exercised conditions.

Biological Response of Irisin Induced by Different Types of Exercise in Obese Subjects: A Non-Inferiority Controlled Randomized Study

Simple Summary

Among healthy male and female obese individuals undergoing a 12-week aerobic exercise program with either moderate intensity endurance or high-intensity interval training for losing weight, a reduction of circulating irisin was observed. Irisin is an important adipo-myokine implicated in the regulation of energy metabolism and cardiovascular health. Sex differences in the circulating levels of this biomarker have been previously reported and are likely related to the different anthropometric features between the sexes. A sex-specific modulation of circulating irisin levels should be further explored to tailor sex-specific training approaches for improving the cardiovascular health of obese subjects.

Abstract

Background: Weight loss through physical exercise is warranted among obese individuals. Recently, a greater benefit in cardiorespiratory fitness was achievable with high-intensity interval training (HIIT) as compared with moderate intensity continuous training. The beneficial effect of training on CV health might be related to a specific modulation of circulating irisin, an adypo-myokine implicated in the regulation of energy expenditure. Methods: The present study investigates the circulating plasma levels of irisin at baseline and in response to 12-week of training program either with HIIT or moderate-intensity continuous training (MICT) among young female and male obese subjects. Clinical, anthropometric, and training characteristics for each participant were available. A sex-disaggregated data for circulating plasma levels of irisin pre- and post-training are provided as well as an adjusted multivariate linear regression model to identify the determinants of post-training irisin levels. Results: Data from a total of 32 obese healthy individuals (47% female, mean age 38.7 years, mean BMI 35.6 kg/m²), randomized in a 1:1 manner to HIIT or MICT were analyzed. Circulating plasma levels of irisin similarly and significantly decreased in both MICT and HIIT interventional groups. Females had higher post-exercise irisin levels than males (6.32 [5.51–6.75] vs. 4.97 [4.57–5.72] μg/mL, p = 0.001). When stratified by an interventional group, a statistically significant difference was observed only for the MICT group (male, 4.76 [4.20–5.45] μg/mL vs. female 6.48 [4.88–6.84] μg/mL p = 0.03). The circulating post-training level of irisin was independently associated with post-training fat-free mass (β −0.34, 95% confidence interval, CI −0.062, −0.006, p = 0.019) in a model adjusted confounders. When female sex was added into the adjusted model, it was retained as the only factor independently associated with irisin levels (β 1.22, 95% CI, 0.50, 1.93, p = 0.002). Conclusions: In obese healthy subjects, circulating irisin levels were reduced in response to 12-weeks of exercise involving either HIIT or MICT. A sex-specific differences in circulating irisin levels at baseline and as biological response to chronic exercise was described. Sex-specific biological response of irisin to exercise should be further explored to tailor sex-specific training approaches for improving the cardiovascular health of obese healthy subjects.

Sestrin2 ablation attenuates the exercise-induced browning of white adipose tissue in C57BL/6J mice

AIM

With exercise, white adipose tissues (WAT) are readily convertible to a "brown-like" state, altering from lipid-storing to energy-catabolizing function, which counteracts obesity and increases insulin sensitivity. Sestrin2 (SESN2) is a stress-inducible protein that can regulate the cold-induced increase of uncoupling protein 1 (UCP1), which is paramount for the thermogenic capacity of brown-like WAT. This study aimed to elucidate the necessity of SESN2 in mediating exercise-induced browning of WAT.

METHODS

We used 8-week, male wild-type and SESN2 knockout C57BL/6J mice to explore the potential role of SESN2 in the exercise-induced WAT browning process. Over a 3-week intervention (sedentary versus treadmill exercise, normal chow versus 60% high-fat diet), we examined the exercise-induced alterations of the browning phenotype in different depots of white fat. In vitro, 3T3-L1 pre-adipocytes and primary adipocytes were used to determine the potential mechanism.

RESULTS

Our data revealed that SESN2 was required for the exercise-induced subcutaneous WAT (scWAT) browning. This may be mediated by higher fibronectin type III domain containing 5 (FNDC5) contents in scWAT locally, rather than skeletal muscle FNDC5 expression and circulating serum irisin levels. SESN2 ablation significantly impaired the exercise-improved glucose metabolism, where browning of scWAT may serve as an essential pathway. Moreover, SESN2 ablation significantly attenuated the exercise-promoted respiratory exchange ratio and indexes of energy metabolism (oxygen uptake and energy expenditure).

CONCLUSION

Taken together, our results provided evidence that SESN2 is a key integrating factor in driving the diverse metabolic benefits conferred by aerobic exercise.

Browning of white adipocytes by gold nanocluster mediated electromagnetic induction heating hyperthermia

Browning of white adipose tissue (WAT) is becoming an attractive therapeutic target for obesity. Great efforts have been made to develop effective approaches to induce browning. Unfortunately, the current methods suffer from a series of disadvantages, such as low efficiency, unsatisfactory stability, and side effects. Herein, we report a new approach to induce browning of 3T3-L1 white adipocytes based on electromagnetic induction heating (EIH) hyperthermia. In particular, adipocyte-targeting aptamer modified gold nanoclusters (Apt-AuNCs) were employed as the mediators of EIH. Apt-AuNCs had good biocompatibility and excellent targeting performance with white adipocytes. After Apt-AuNCs/EIH treatment, adipocytes with characteristic multilocular and small lipid droplets increased, and the content of triglycerides reduced effectively. Apt-AuNCs/EIH treatment also significantly increased the mitochondrial activity in adipocytes. Meanwhile, the mRNA levels of key genes that are involved in browning, for example UCP1, PRDM16, PPARγ, and PGC-1α, were upregulated. Finally, the induction mechanism of Apt-AuNCs/EIH on browning of white adipocytes was explained by the synergistic effects of EIH hyperthermia and pharmacological action of AuNCs. To the best of our knowledge, this is the first attempt on induction of browning by metal nanocluster-mediated EIH hyperthermia, thus providing an interesting and efficient channel for obesity treatment.

Adipocyte Biology from the Perspective of In Vivo Research: Review of Key Transcription Factors

Obesity and type 2 diabetes are both significant contributors to the contemporary pandemic of non-communicable diseases. Both disorders are interconnected and associated with the disruption of normal homeostasis in adipose tissue. Consequently, exploring adipose tissue differentiation and homeostasis is important for the treatment and prevention of metabolic disorders. The aim of this work is to review the consecutive steps in the postnatal development of adipocytes, with a special emphasis on in vivo studies. We gave particular attention to well-known transcription factors that had been thoroughly described in vitro, and showed that the in vivo research of adipogenic differentiation can lead to surprising findings.

Exercise-Mediated Browning of White Adipose Tissue: Its Significance, Mechanism and Effectiveness

As a metabolic organ, adipose tissue plays an important role in regulating metabolism. In adults, most adipose tissue is white adipose tissue (WAT), and excessive expansion of WAT will lead to obesity. It is worth noting that exercise can reduce the fat mass. There is also a lot of evidence that exercise can promote the browning of WAT, which is beneficial for metabolic homeostasis. Multiple factors, including reactive oxygen species (ROS), metabolites, nervous system, exerkines and lipolysis can facilitate exercise-mediated browning of WAT. In this review, the roles and the underlying mechanisms of exercise-mediated browning of WAT are summarized. The effects of different styles of exercise on the browning of WAT are also discussed, with the aim to propose better exercise strategies to enhance exercise-mediated browning of WAT, so as to promote metabolic health. Finally, the different reactivity of WAT at different anatomical sites to exercise-mediated browning is reviewed, which may provide potential suggestion for people with different fat loss needs.

Exercise Intervention Mitigates Pathological Liver Changes in NAFLD Zebrafish by Activating SIRT1/AMPK/NRF2 Signaling

Non-alcoholic fatty liver disease (NAFLD) is a common disease that causes serious liver damage. Exercise is recognized as a non-pharmacological tool to improve the pathology of NAFLD. However, the antioxidative effects and mechanisms by which exercise ameliorates NAFLD remain unclear. The present study conducted exercise training on zebrafish during a 12-week high-fat feeding period to study the antioxidant effect of exercise on the liver. We found that swimming exercise decreased lipid accumulation and improved pathological changes in the liver of high-fat diet-fed zebrafish. Moreover, swimming alleviated NOX4-derived reactive oxygen species (ROS) overproduction and reduced methanedicarboxylic aldehyde (MDA) levels. We also examined the anti-apoptotic effects of swimming and found that it increased the expression of antiapoptotic factor bcl2 and decreased the expression of genes associated with apoptosis (caspase3, bax). Mechanistically, swimming intervention activated SIRT1/AMPK signaling-mediated lipid metabolism and inflammation as well as enhanced AKT and NRF2 activation and upregulated downstream antioxidant genes. In summary, exercise attenuates pathological changes in the liver induced by high-fat diets. The underlying mechanisms might be related to NRF2 and mediated by SIRT1/AMPK signaling.

A Novel Identified Peptide Hormone "Metabolitin" Attenuates Lipid Absorption in the Small Intestine of Diabetic Mice with Nonalcoholic Fatty Liver Disease by Regulating Neurotensin and AMPK Signaling Pathway

AIM

The purpose of this study was to explore the effect of a novel identified peptide hormone "metabolitin" on lipid absorption in the small intestine of mice with type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD) and potential mechanisms.

METHODS

T2DM was induced in mice by 4-6 weeks of high-fat diets followed by intraperitoneal injection of 35 mg/kg STZ. NAFLD was induced in diabetic mice by a month of high-fat diets. Oral administration of 4 pmol/g or 12 pmol/g metabolitin every two days was performed during one-month high-fat diets. Triglyceride (TG) and total cholesterol (TC) detection and Oil Red O staining were performed to evaluate lipid absorption. The neurotensin (NT) levels in the intestinal tissues and serum were determined by ELISA. Lipogenesis- and lipolysis-related proteins, AMP-activated protein kinase (AMPK), and p-AMPK were examined by Western blot analysis.

RESULTS

It was found that glucose tolerance test (GTT), insulin tolerance test (ITT), TG, and TC indicated lower levels in the serum of NAFLD/T2DM mice receiving 4 pmol/g and 12 pmol/g metabolitin compared to the mice receiving normal saline (P < 0.05). No significant difference was noted in the TC level of the feces among mice with different diets (P > 0.05), but compared to NAFLD/T2DM mice with normal saline, the mice administrated with 4 pmol/g and 12 pmol/g metabolitin revealed much higher TG levels in the feces (P < 0.05). The results of Oil Red O staining revealed that the intestinal epithelial cells of NAFLD/T2DM mice receiving 12 pmol/g metabolitin indicated resistance to lipid absorption and the area of staining was smaller than that of NAFLD/T2DM mice with normal saline (P < 0.05). The NAFLD/T2DM mice receiving 4 pmol/g and 12 pmol/g metabolitin showed a higher extent of p-AMPK concomitant with lower levels of NT in the serum and small intestine than the mice with normal saline (P < 0.05). Western blot analysis also suggested that NAFLD/T2DM mice receiving 4 pmol/g and 12 pmol/g metabolitin revealed lower expressions in fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase-1 (SCD-1), and sterol regulatory element-binding transcription factor-1 (SREBP1) proteins and higher expressions in carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor alpha (PPARα), and fatty acid translocase (CD36) proteins than NAFLD/T2DM mice with normal saline (P < 0.05).

CONCLUSION

According to the data we observed, oral administration of metabolitin could attenuate lipid absorption in the small intestine of NAFLD/T2DM mice, which may be a novel therapeutic approach for NAFLD/T2DM.

Dietary Intervention, When Not Associated With Exercise, Upregulates Irisin/FNDC5 While Reducing Visceral Adiposity Markers in Obese Rats

Obesity is an epidemic disease and the expansion of adipose tissue, especially visceral fat, promotes the secretion of factors that lead to comorbidities such as diabetes and cardiovascular diseases. Thus, diet and exercise have been proposed as an intervention to reverse these complications. An adipocytokine, known as irisin, mediates the beneficial effects of exercise. It has been proposed as a therapeutic potential in controlling obesity. In view of the above, this paper attempts to determine the modulation of irisin, visceral adiposity and biochemical markers in response to dietary intervention and aerobic exercise. To do this, 52 diet-induced obese male Wistar rats were divided into the following four groups: high-fat diet and exercise (HFD-Ex); HFD-Sedentary (HFD-Sed); chow-diet and exercise (CD-Exercise); and CD-Sed. The exercise-trained group performed a treadmill protocol for 60 min/day, 3 days/week for 8 weeks. Body mass (BM), body fat (BF), fat mass (FM), and fat-free mass (FFM) were analyzed. Mesenteric (MES), epididymal (EPI), and retroperitoneal (RET) adipose tissue was collected and histological analysis was performed. Biochemical irisin, triglycerides, glucose, insulin and inflammatory markers were determined and, FNDC5 protein expression was analyzed. In this study, the diet was the most important factor in reducing visceral adiposity in the short and long term. Exercise was an important factor in preserving muscle mass and reducing visceral depots after a long term. Moreover, the combination of diet and exercise can enhance these effects. Diet and exercise exclusively were the factors capable of increasing the values of irisin/FNDC5, however it did not bring cumulative effects of both interventions. Prescriptions to enhance the obesity treatments should involve reducing visceral adiposity by reducing the fat content in the diet associated with aerobic exercise.

The TOTUM-63 Supplement and High-Intensity Interval Training Combination Limits Weight Gain, Improves Glycemic Control, and Influences the Composition of Gut Mucosa-Associated Bacteria in Rats on a High Fat Diet

Obesity and prediabetes are the two strongest risk factors of type 2 diabetes. It has been reported that TOTUM-63, a polyphenol-rich plant extract, has beneficial effects on body weight (BW) and insulin resistance in mice fed a high fat diet (HFD). The study aim was to determine whether high-intensity interval training (HIIT) and/or TOTUM-63 supplementation improved body composition and glycemic control and gut microbiota composition in a Western diet-induced obesity rat model. Wistar rats received a standard diet (CTRL; control; n = 12) or HFD (HFD; n = 48) for 16 weeks. Then, HFD rats were divided in four groups: HFD, HFD + TOTUM-63 (T63), HFD + HIIT (HIIT), and HFD + HIIT +T63 (HIIT + T63). Training was performed 4 days/week for 12 weeks. TOTUM-63 was included in diet composition (2%). The HIIT + T63 combination significantly limited BW gain, without any energy intake modulation, and improved glycemic control. BW variation was correlated with increased α-diversity of the colon mucosa microbiota in the HIIT + T63 group. Moreover, the relative abundance of Anaeroplasma, Christensenellaceae and Oscillospira was higher in the HIIT + T63 group. Altogether, these results suggest that the HIIT and TOTUM-63 combination could be proposed for the management of obesity and prediabetes.

Impact of acute exercise on immediate and following early post-exercise FGF-21 concentration in adults: systematic review and meta-analysis

PURPOSE/OBJECTIVE

The aim of this study was to quantify circulating fibroblast growth factor 21 (FGF-21) changes during and immediately after acute exercise and, based on body weight, to identify the subgroups exhibiting the largest response.

METHODS

The PubMed, Web of Science, and Cochrane Library electronic databases were searched up to December 2019 for studies published in English peer-reviewed journals. Studies that evaluated the effects of acute exercise on FGF-21 concentrations immediately after and 1 and 3 h post-exercise in adults were included. Random effects models were used for analyses, with data reported as standardized mean difference (SMD) and 95% confidence interval, and the risk of heterogeneity was evaluated. Subgroup analysis of subjects with normal weight and obesity/overweight was performed.

RESULTS

A total of seven studies involving 125 participants (age 35.95 (21-64) years and BMI 25.89 (21.30-35.46) kg/m²) were included. Overall, acute exercise increased FGF-21 (d = 0.18; 95% CI 0.01 to 0.35, p = 0.02) and this remained for 1 h post-exercise FGF-21 (d = 0.59; 95% CI 0.33 to 0.86, p = 0.001). Three hours after exercise, FGF-21 was restored to near baseline values (d = - 0.05; 95% CI - 0.34 to 0.22, p = 0.68). Acute exercise raised FGF-21 concentrations in normal weight participants (d = 0.57, p = 0.001) and tended to increase in overweight and obese participants (d = 0.79, p = 0.05) 1 h post-exercise.

CONCLUSION

Acute exercise increases circulating FGF-21, irrespective of body weight.

Resistance exercise training induces subcutaneous and visceral adipose tissue browning in Swiss mice

Aerobic exercise training (AER) may promote several adaptations in white adipose tissue (WAT), including a phenotypic change known as browning. The present study aimed at assessing if resistance exercise training (RES) would be as efficient as AER in inducing a brown-like adipocyte reprogramming in WAT. Thirty Swiss male mice were randomly divided into 3 groups with 10 animals each: 1) sedentary (SED), 2) AER, and 3) RES. After the adaptation training, an incremental test was performed at the beginning of each week to adjust training load. Mice were submitted to 8 wk of AER or RES. After the experimental period, inguinal and retroperitoneal WAT (iWAT and rpWAT) and brown adipose tissue (BAT) were collected. The prescription of AER and RES was effective in increasing the performance of both groups. Also, RES presented a lower body weight than AER/SED. AER and RES reduced the area of iWAT and rpWAT adipocytes and the lipid area of BAT, induced an increase of vascular endothelial growth factor (VEGF) and cluster of differentiation 31 (CD31) and uncoupling protein 1 (UCP-1), and increased the expression of selective genes of brown and beige phenotype in adipocytes after 8 wk. In general, we demonstrated here that AER and RES training similarly induced the browning of iWAT and rpWAT.NEW & NOTEWORTHY Aerobic exercise training (AER) induces the browning of white adipose tissue, turning adipocytes multilocular, highly vascularized and expressing uncoupling protein 1 (UCP-1). The current study compared the efficiency of resistance to aerobic exercise training to promote a brown-like phenotype. Our results suggest that both types of training similarly induce subcutaneous and visceral adipose tissue browning.

Human white-fat thermogenesis: Experimental and meta-analytic findings

White adipose tissue (WAT) thermogenic activity may play a role in whole-body energy balance and two of its main regulators are thought to be environmental temperature (T_env) and exercise. Low T_env may increase uncoupling protein one (UCP1; the main biomarker of thermogenic activity) in WAT to regulate body temperature. On the other hand, exercise may stimulate UCP1 in WAT, which is thought to alter body weight regulation. However, our understanding of the roles (if any) of T_env and exercise in WAT thermogenic activity remains incomplete. Our aim was to examine the impacts of low T_env and exercise on WAT thermogenic activity, which may alter energy homeostasis and body weight regulation. We conducted a series of four experimental studies, supported by two systematic reviews and meta-analyses. We found increased UCP1 mRNA (p = 0.03; but not protein level) in human WAT biopsy samples collected during the cold part of the year, a finding supported by a systematic review and meta-analysis (PROSPERO review protocol: CRD42019120116). Additional clinical trials (NCT04037371; NCT04037410) using Positron Emission Tomography/Computed Tomography (PET/CT) revealed no impact of low T_env on human WAT thermogenic activity (p > 0.05). Furthermore, we found no effects of exercise on UCP1 mRNA or protein levels (p > 0.05) in WAT biopsy samples from a human randomized controlled trial (Clinical trial: NCT04039685), a finding supported by systematic review and meta-analytic data (PROSPERO review protocol: CRD42019120213). Taken together, the present experimental and meta-analytic findings of UCP1 and SUV_max, demonstrate that cold and exercise may play insignificant roles in human WAT thermogenic activity. Abbreviations: WAT:White adipose tissue; T_env: Environmental temperature; UCP1: Uncoupling protein one; BAT: Brown adipose tissue; BMI:Body mass index; mRNA: Messenger ribonucleic acid; RCT: Randomized controlled trial; WHR: Waist-to-hip ratio; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-analyses; PET/CT: Positron Emission Tomography and Computed Tomography; REE: Resting energy expenditure; ¹⁸F-FDG: F¹⁸ fludeoxyglucose; VO₂peak:Peak oxygen consumption; 1RM: One repetition maximum; SUV_max: Maximum standardized uptake value; Std: Standardized mean difference.