Effect of resveratrol on expression of genes involved thermogenesis in mice and humans

Oral supplementation with resveratrol improves hormonal profile and increases expression of genes associated with thermogenesis in oophorectomy mice

Menopause causes important bodily and metabolic changes, which favor the increased occurrence of cardiovascular diseases, obesity, diabetes, and osteoporosis. Resveratrol exerts proven effects on body metabolism, improving glucose and lipid homeostasis and reducing inflammation and oxidative stress in various organs and tissues. Accordingly, this study evaluates the effects of resveratrol supplementation on the expression of markers associated with thermogenesis in brown adipose tissue, and on the body, metabolic and hormonal parameters of female mice submitted to bilateral oophorectomy. Eighteen female mice were randomized into three groups: G1: control (CONTROL), G2: oophorectomy (OOF), and G3: oophorectomy + resveratrol (OOF + RSV); the animals were kept under treatment for twelve weeks, being fed a standard diet and treated with resveratrol via gavage. Body, biochemical, hormonal, and histological parameters were measured; in addition to the expression of markers associated with thermogenesis in brown adipose tissue. The results showed that animals supplemented with resveratrol showed reduced body weight and visceral adiposity, in addition to glucose, total cholesterol, and triglyceride levels; decreased serum FSH levels and increased estrogen levels were observed compared to the OOF group and mRNA expression of PRDM16, UCP1, and SIRT3 in brown adipose tissue. The findings of this study suggest the important role of resveratrol in terms of improving body, metabolic, and hormonal parameters, as well as modulating markers associated with thermogenesis in brown adipose tissue of female mice submitted to oophorectomy.

Hydrogen Sulfide and Irisin, Potential Allies in Ensuring Cardiovascular Health

Irisin is a myokine secreted under the influence of physical activity and exposure to low temperatures and through different exogenous stimuli by the cleavage of its precursor, fibronectin type III domain-containing protein 5 (FNDC5). It is mainly known for maintaining of metabolic homeostasis, promoting the browning of white adipose tissue, the thermogenesis process, and glucose homeostasis. Growing experimental evidence suggests the possible central role of irisin in the regulation of cardiometabolic pathophysiological processes. On the other side, hydrogen sulfide (H2S) is well recognized as a pleiotropic gasotransmitter that regulates several homeostatic balances and physiological functions and takes part in the pathogenesis of cardiometabolic diseases. Through the S-persulfidation of cysteine protein residues, H2S is capable of interacting with crucial signaling pathways, exerting beneficial effects in regulating glucose and lipid homeostasis as well. H2S and irisin seem to be intertwined; indeed, recently, H2S was found to regulate irisin secretion by activating the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)/FNDC5/irisin signaling pathway, and they share several mechanisms of action. Their involvement in metabolic diseases is confirmed by the detection of their lower circulating levels in obese and diabetic subjects. Along with the importance of metabolic disorders, these modulators exert favorable effects against cardiovascular diseases, preventing incidents of hypertension, atherosclerosis, heart failure, myocardial infarction, and ischemia-reperfusion injury. This review, for the first time, aims to explore the role of H2S and irisin and their possible crosstalk in cardiovascular diseases, pointing out the main effects exerted through the common molecular pathways involved.

Natural compounds as obesity pharmacotherapies

Obesity has become a serious global public health problem, affecting over 988 million people worldwide. Nevertheless, current pharmacotherapies have proven inadequate. Natural compounds have garnered significant attention due to their potential antiobesity effects. Over the past three decades, ca. 50 natural compounds have been evaluated for the preventive and/or therapeutic effects on obesity in animals and humans. However, variations in the antiobesity efficacies among these natural compounds have been substantial, owing to differences in experimental designs, including variations in animal models, dosages, treatment durations, and administration methods. The feasibility of employing these natural compounds as pharmacotherapies for obesity remained uncertain. In this review, we systematically summarized the antiobesity efficacy and mechanisms of action of each natural compound in animal models. This comprehensive review furnishes valuable insights for the development of antiobesity medications based on natural compounds.

Resveratrol for the Management of Human Health: How Far Have We Come? A Systematic Review of Resveratrol Clinical Trials to Highlight Gaps and Opportunities

Resveratrol has long been proposed as being beneficial to human health across multiple morbidities, yet there is currently no conclusive clinical evidence to advocate its recommendation in any healthcare setting. A large cohort with high-quality clinical data and clearly defined biomarkers or endpoints are required to draw meaningful conclusions. This systematic review compiles every clinical trial conducted using a defined dose of resveratrol in a purified form across multiple morbidities to highlight the current 'state-of-play' and knowledge gaps, informing future trial designs to facilitate the realisation of resveratrol's potential benefits to human health. Over the last 20 years, there have been almost 200 studies evaluating resveratrol across at least 24 indications, including cancer, menopause symptoms, diabetes, metabolic syndrome, and cardiovascular disease. There are currently no consensus treatment regimens for any given condition or endpoint, beyond the fact that resveratrol is generally well-tolerated at a dose of up to 1 g/day. Additionally, resveratrol consistently reduces inflammatory markers and improves aspects of a dysregulated metabolism. In conclusion, over the last 20 years, the increasing weight of clinical evidence suggests resveratrol can benefit human health, but more large, high-quality clinical trials are required to transition this intriguing compound from health food shops to the clinic.

Antiobesity pathways of pterostilbene and resveratrol: a comprehensive insight

It may not always be possible for obese individuals to limit energy intake or to provide and/or maintain greater energy expenditure through exercise and physical activity. Therefore, the search for effective methods for obesity continues. Recently, the anti-obesity effect of stilbenes has attracted attention. In this review, aim was evaluating the effect of pterostilbene and resveratrol against obesity and the possible mechanisms in this effect. Dietary phytochemicals can induce body weight loss by increasing basal metabolic rate and thermogenesis and/or altering lipid metabolism. Stilbenes are products of the plant phenylpropanoid pathway. Very important mechanisms for the anti-obesity impact belonging to resveratrol as well as pterostilbene include thermogenic activation in brown adipose tissue alongside the browning of white adipose tissue. Considering nutrition and dietary habits, which have an important place in lifestyle changes for both the prevention and the treatment of obesity, pterostilbene and resveratrol, which are polyphenols and stilbenes, are seen as promising. However, optimal dose, duration, mechanism, long-term safety, side effects, combination, elucidation of genomic interactions, and lifestyle modifications should be considered.

Plant-Derived Nutraceuticals Involved in Body Weight Control by Modulating Gene Expression

Obesity is the most prevalent health problem in the Western world, with pathological body weight gain associated with numerous co-morbidities that can be the main cause of death. There are several factors that can contribute to the development of obesity, such as diet, sedentary lifestyle, and genetic make-up. Genetic predispositions play an important role in obesity, but genetic variations alone cannot fully explain the explosion of obesity, which is why studies have turned to epigenetics. The latest scientific evidence suggests that both genetics and environmental factors contribute to the rise in obesity. Certain variables, such as diet and exercise, have the ability to alter gene expression without affecting the DNA sequence, a phenomenon known as epigenetics. Epigenetic changes are reversible, and reversibility makes these changes attractive targets for therapeutic interventions. While anti-obesity drugs have been proposed to this end in recent decades, their numerous side effects make them not very attractive. On the other hand, the use of nutraceuticals for weight loss is increasing, and studies have shown that some of these products, such as resveratrol, curcumin, epigallocatechin-3-gallate, ginger, capsaicin, and caffeine, can alter gene expression, restoring the normal epigenetic profile and aiding weight loss.

Light-emitting diode (LED) photobiomodulation regulates thermogenesis and lipogenesis markers in adipose tissue and improves anthropometric and metabolic parameters in obese mice

To evaluate the effects of Light-Emitting Diode (LED) irradiation on the expression of thermogenesis and lipogenesis-associated markers in adipose tissue and metabolic parameters of obese mice. Twenty-four male mice were divided into four groups: i) ST fed standard diet; ii) HCD fed hyperglycemic diet; iii) LED + I fed hyperglycemic diet and irradiated with LED in the interscapular region; iv) LED + A fed hyperglycemic diet and irradiated with LED in the abdominal region. The first phase of the study comprehended the induction of obesity for 12 weeks. Next, the animals were submitted to six irradiation sessions (days 1, 3, 7, 10, 14, and 21) using a 660-nm LED (5.77 J/cm² at 48,1 mW/cm²). Anthropometric, biochemical, and histological parameters and the expression of thermogenesis and lipogenesis-associated markers were assessed in adipose tissue. There was diminished weight gain between the HCD and LED + A groups (ST: 0.37 ± 0.65; HCD: 3.10 ± 0.89; LED + I: -1.26 ± 0.83; LED + A: -2.07 ± 1.27 g; p < 0.018). There was a 33.3% and 23.8% reduction in epidydimal adipose tissue weight and a 25% and 10.7% in the visceral adiposity for the LED + I and LED + A groups, respectively, when compared with HCD. There was a decreased accumulation of fat droplets in adipose tissue in LED + A and LED + I groups. Additionally, LED irradiation was associated with increased mRNA expression of uncoupling protein 1 (UCP1) in the brown adipose tissue (ST: 2.27 ± 0.19; HCD: 1.54 ± 0.12; LED + I: 2.44 ± 0.22; p = 0.014) and decreased fatty acid synthetase (FAS) expression in epidydimal adipose tissue (ST: 0.79 ± 0.13; HCD: 1.59 ± 0.13; LED + A: 0.85 ± 0.04; p = 0.0008). LED treatment improved anthropometric parameters, possibly associated with the histological alterations, thermogenesis and lipogenesis markers in white adipose tissue, and expression modulation in brown adipose tissue.

Irisin enhances longevity by boosting SIRT1, AMPK, autophagy and telomerase

Ageing is characterised by the accumulation of molecular and cellular damage through time, leading to a decline in physical and mental abilities. Currently, society has experienced a rapid increase in life expectancy, which has led to an increase in age-associated diseases. Therefore, it is crucial to study the process of ageing to guarantee the best conditions in the final stages of life. In recent years, interest has increased in a myokine known as irisin, which is secreted during physical exercise. This polypeptide hormone is produced by various organs, mainly muscle, and once it is released into the blood, it performs a wide variety of functions that are involved in metabolic control and may be relevant during some of the diseases associated with ageing. The aim of this review is to highlight the recent studies of irisin, such as its mechanism of expression, blood release, distribution, tissue target and participation in various cellular metabolic reactions and the relationship with key anti-ageing pathways such as adenosine monophosphate-activated protein kinase, silent information regulator T 1, autophagy and telomerase. In conclusion, irisin is a key player during the ageing process and it could be a novel target molecule for the therapeutic approach to boost longevity pathways. However, more research will be necessary to use this promising hormone for this gain.

Potential of enhancing anti-obesogenic agriceuticals by applying sustainable fertilizers during plant cultivation

Overweight and obesity are two of the world's biggest health problems. They are associated with excessive fat accumulation resulting from an imbalance between energy consumed and energy expended. Conventional therapies for obesity commonly include synthetic drugs and surgical procedures that can lead to serious side effects. Therefore, developing effective, safe, and readily available new treatments to prevent and treat obesity is highly relevant. Many plant extracts have shown anti-obesogenic potential. These plant extracts are composed of different agriceuticals such as fibers, phenolic acids, flavonoids, anthocyanins, alkaloids, lignans, and proteins that can manage obesity by suppressing appetite, inhibiting digestive enzymes, reducing adipogenesis and lipogenesis, promoting lipolysis and thermogenesis, modulating gut microbiota and suppressing obesity-induced inflammation. These anti-obesogenic agriceuticals can be enhanced in plants during their cultivation by applying sustainable fertilization strategies, improving their capacity to fight the obesity pandemic. Biofertilization and nanofertilization are considered efficient, eco-friendly, and cost-effective strategies to enhance plant growth and development and increase the content of nutrients and bioactive compounds, representing an alternative to overproducing the anti-obesogenic agriceuticals of interest. However, further research is required to study the impact of anti-obesogenic plant species grown using these agricultural practices. This review presents the current scenario of overweight and obesity; recent research work describing different plant species with significant effects against obesity; and several reports exhibiting the potential of the biofertilization and nanofertilization practices to enhance the concentrations of bioactive molecules of anti-obesogenic plant species.

The Role and Regulatory Mechanism of Brown Adipose Tissue Activation in Diet-Induced Thermogenesis in Health and Diseases

Brown adipose tissue (BAT) has been considered a vital organ in response to non-shivering adaptive thermogenesis, which could be activated during cold exposure through the sympathetic nervous system (SNS) or under postprandial conditions contributing to diet-induced thermogenesis (DIT). Humans prefer to live within their thermal comfort or neutral zone with minimal energy expenditure created by wearing clothing, making shelters, or using an air conditioner to regulate their ambient temperature; thereby, DIT would become an important mechanism to counter-regulate energy intake and lipid accumulation. In addition, there has been a long interest in the intriguing possibility that a defect in DIT predisposes one to obesity and other metabolic diseases. Due to the recent advances in methodology to evaluate the functional activity of BAT and DIT, this updated review will focus on the role and regulatory mechanism of BAT biology in DIT in health and diseases and whether these mechanisms are applicable to humans.

The role of irisin in metabolic flexibility: beyond adipose tissue browning

Metabolic flexibility is the ability to adapt to physiological and environmental changes in metabolic demand. Irisin was originally discovered as an exercise-induced myokine involved in fat browning. In this review, we summarize emerging evidence for the role of irisin in regulating glucose metabolism and insulin sensitivity in skeletal muscle, neuroplasticity and satiety in central nervous system, β cell function and insulin secretion in the pancreas, bone remodeling, and adipose tissue function, which together orchestrate whole-body metabolic flexibility. Irisin is a key communicating mediator between skeletal muscle and other organs, and its manipulation could be a promising therapeutic strategy for treating obesity and related metabolic disorders. Teaser: This review summarizes recent progress in manipulating metabolic flexibility with irisin, and discusses its potential application as a drug target to treat obesity and related metabolic disorders.

Neutrophil extracellular traps (NETs) modulate inflammatory profile in obese humans and mice: adipose tissue role on NETs levels

BACKGROUND

Neutrophil extracellular traps (NETs) are a recently discovered neutrophil defense mechanism which modulates several inflammatory conditions contributing to metabolic profile alterations. Therefore, the present study aimed to evaluate the production of NETs in obese patients and mice, verifying the possible mechanisms associated with the release of NETs by the adipose tissue.

METHODS AND RESULTS

The present study investigated NETs production in human adipose tissue and also showing the neutrophils using intravital microscopy in mouse epididymal adipose tissue. Blood and white adipose tissues were obtained from eutrophic and obese individuals and from mice. Lipid, glycemic and leukocyte profiles were evaluated, as well as the levels of NETs and its markers. Bioinformatics and proteomics analyses were performed and the identified key proteins were measured. The main findings showed that the inflammatory markers interleukin-8 (IL-8), heat shock protein 90 (HSP90) and the E1 heat shock protein family (HSPE1) can be modulated by the NETs levels in obesity. Obesity has also been associated with increased cholesterol, glucose intolerance, ionic calcium and NETs. We also observed an increase in catalase and a decreased superoxide dismutase activity. Bioinformatics and proteomics analyses revealed that IL-8, HSP90 and HSPE1 were associated with obesity, inflammation and NETs release.

CONCLUSIONS

In conclusion, the present study shows an increase in NETs production during obesity associated with important inflammatory markers in adipose.

Food phenolics stimulate adipocyte browning via regulating gut microecology

Fat browning has piqued the interest of researchers as a potential target for treating obesity and related metabolic disorders. Recruitment of brown adipocytes leads to enhanced energy dissipation and reduced adiposity, thus facilitating the maintenance of metabolic homeostasis. Evidence is increasing to support the crucial roles of polyphenols and gut microecology in turning fat "brown". However, it is not clear whether the intestinal microecology is involved in polyphenol-mediated regulation of adipose browning, so this concept is worthy of exploration. In this review, we summarize the current knowledge, mostly from studies with murine models, supporting the concept that the effects of food phenolics on brown fat activation and white fat browning can be attributed to their regulatory actions on gut microecology, including microbial community profile, gut metabolites, and gut-derived hormones. Furthermore, the potential underlying pathways involved are also discussed. Basically, understanding gut microecology paves the way to determine the underlying roles and mechanisms of food phenolics in adipose browning.

Anthocyanin oligomers stimulate browning in 3T3-L1 white adipocytes via activation of the β3-adrenergic receptor and ERK signaling pathway

Microbial fermentation of grape-skin extracts is found to synthesize anthocyanin oligomers (AO), which are more active than the monomeric anthocyanins that are effective for some metabolic diseases such as diabetes and obesity. This study investigated the functional role of AO in 3T3-L1 white adipocyte metabolism, with a focus on inducing browning. To achieve this, we determined the expressions of core genes and protein markers responsible for browning and lipid metabolism in response to AO treatment of 3T3-L1 white adipocytes. AO exposure significantly increases the expressions of beige-specific genes (Cidea, Cited1, Ppargc1α, Prdm16, Tbx1, Tmem26, and Ucp1) and brown-fat signature proteins (UCP1, PRDM16, and PGC-1α), and suppresses the expressions of lipogenic marker proteins while enhancing the protein levels of lipolysis in white adipocytes. The mechanistic study revealed stimulation of white fat browning via activation of the β3-AR/PKA/p38 axis and ERK/CREB signaling pathway subsequent to AO treatment. In conclusion, our current findings indicate the beneficial effects of AO for the treatment of obesity with interesting properties such as regulating the browning of adipocytes and increasing thermogenic activity. Although further research based on animal models or clinical trials remains, AO treatment can bring more insights into the treatment of obesity and metabolic syndrome.

Recent Advances in Health Benefits of Stilbenoids

Biological targeting or molecular targeting is the main strategy in drug development and disease prevention. However, the problem of "off-targets" cannot be neglected. Naturally derived drugs are preferred over synthetic compounds in pharmaceutical markets, and the main goals are high effectiveness, lower cost, and fewer side effects. Single-target drug binding may be the major cause of failure, as the pathogenesis of diseases is predominantly multifactorial. Naturally derived drugs are advantageous because they are expected to have multitarget effects, but not off-targets, in disease prevention or therapeutic actions. The capability of phytochemicals to modulate molecular signals in numerous diseases has been widely discussed. Among them, stilbenoids, especially resveratrol, have been well-studied, along with their potential molecular targets, including AMPK, Sirt1, NF-κB, PKC, Nrf2, and PPARs. The analogues of resveratrol, pterostilbene, and hydroxylated-pterostilbene may have similar, if not more, potential biological targeting effects compared with their original counterpart. Furthermore, new targets that have been discussed in recent studies are reviewed in this paper.

Fibronectin type III domain-containing 5 in cardiovascular and metabolic diseases: a promising biomarker and therapeutic target

Cardiovascular and metabolic diseases are the leading causes of death and disability worldwide and impose a tremendous socioeconomic burden on individuals as well as the healthcare system. Fibronectin type III domain-containing 5 (FNDC5) is a widely distributed transmembrane glycoprotein that can be proteolytically cleaved and secreted as irisin to regulate glycolipid metabolism and cardiovascular homeostasis. In this review, we present the current knowledge on the predictive and therapeutic role of FNDC5 in a variety of cardiovascular and metabolic diseases, such as hypertension, atherosclerosis, ischemic heart disease, arrhythmia, metabolic cardiomyopathy, cardiac remodeling, heart failure, diabetes mellitus, and obesity.

A comprehensive insight into the potential effects of resveratrol supplementation on SIRT-1: A systematic review

BACKGROUND AND AIMS

Silent information regulator 1 (Sirt1) involved in histone stability, transcriptional activity, and translocation. This systematic review aimed to summarize the effects of Resveratrol on Sirt1 expression.

MATERIALS AND METHODS

Electronic databases including Scopus, Medline and web of knowledge were searched up to March 2020.

RESULTS

Out of 801 studies identified in our search finally 12 articles included. Totally six studies evaluated the effects of resveratrol on SIRT1 gene expression, and six articles investigate protein expression.

CONCLUSION

The results of the included studies showed that resveratrol supplementation had beneficial effects on protein and gene expression of SIRT1.

Polyphenols as adjunctive treatments in psychiatric and neurodegenerative disorders: Efficacy, mechanisms of action, and factors influencing inter-individual response

The pathophysiology of psychiatric and neurodegenerative disorders is complex and multifactorial. Polyphenols possess a range of potentially beneficial mechanisms of action that relate to the implicated pathways in psychiatric and neurodegenerative disorders. The aim of this review is to highlight the emerging clinical trial and preclinical efficacy data regarding the role of polyphenols in mental and brain health, elucidate novel mechanisms of action including the gut microbiome and gene expression, and discuss the factors that may be responsible for the mixed clinical results; namely, the role of interindividual differences in treatment response and the potentially pro-oxidant effects of some polyphenols. Further clarification as part of larger, well conducted randomized controlled trials that incorporate precision medicine methods are required to inform clinical efficacy and optimal dosing regimens.

Diabetes Mellitus and Cardiovascular Diseases: Nutraceutical Interventions Related to Caloric Restriction

Type 2 diabetes (T2DM) and cardiovascular disease (CVD) are closely associated and represent a key public health problem worldwide. An excess of adipose tissue, NAFLD, and gut dysbiosis establish a vicious circle that leads to chronic inflammation and oxidative stress. Caloric restriction (CR) is the most promising nutritional approach capable of improving cardiometabolic health. However, adherence to CR represents a barrier to patients and is the primary cause of therapeutic failure. To overcome this problem, many different nutraceutical strategies have been designed. Based on several data that have shown that CR action is mediated by AMPK/SIRT1 activation, several nutraceutical compounds capable of activating AMPK/SIRT1 signaling have been identified. In this review, we summarize recent data on the possible role of berberine, resveratrol, quercetin, and L-carnitine as CR-related nutrients. Additionally, we discuss the limitations related to the use of these nutrients in the management of T2DM and CVD.

Activation of Brown Adipose Tissue and Promotion of White Adipose Tissue Browning by Plant-based Dietary Components in Rodents: A Systematic Review

Activation of brown adipose tissue (BAT) and promotion of white adipose tissue (WAT) browning is considered a potential tool to combat obesity and cardiometabolic disorders. The use of plant-based dietary components has become one of the most used strategies for activating BAT and promoting WAT browning in rodents. The main reason is because plant-based dietary components are usually recognized as safe when the dose is properly adjusted, and they can easily be administrated by being added to the diet or dissolved in water. The present systematic review aimed to study the effects of plant-based dietary components on activation of BAT and promotion of WAT browning in rodents. A systematic search of PubMed and Scopus (from 1978 to 2019) identified eligible studies. Studies assessing the effects of plant-based dietary components added to diet and/or water on uncoupling protein 1 (UCP1) expression in BAT and/or WAT were included. Studies that used dietary components of animal origin, did not specify the effects on UCP1, or were conducted in other species different from mice or rats were excluded. Of 3919 studies identified in the initial screening, 146 studies were finally included in the review. We found that tea extract catechins, resveratrol, capsaicin and capsinoids, cacao extract flavanols, and quercetin were the most studied components. Scientific evidence suggests that some of these dietary components activate BAT and promote WAT browning via activation of the AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) pathways. These findings reveal that there is strong scientific evidence supporting the use of plant-based dietary components to activate BAT and promote WAT browning in rodents and thus to potentially combat obesity and cardiometabolic disorders.

Natural Bioactive Compounds as Potential Browning Agents in White Adipose Tissue

The epidemic of overweight and obesity underlies many common metabolic diseases. Approaches aimed to reduce energy intake and/or stimulate energy expenditure represent potential strategies to control weight gain. Adipose tissue is a major energy balancing organ. It can be classified as white adipose tissue (WAT) and brown adipose tissue (BAT). While WAT stores excess metabolic energy, BAT dissipates it as heat via adaptive thermogenesis. WAT also participates in thermogenesis by providing thermogenic fuels and by directly generating heat after browning. Browned WAT resembles BAT morphologically and metabolically and is classified as beige fat. Like BAT, beige fat can produce heat. Human adults have BAT-like or beige fat. Recruitment and activation of this fat type have the potential to increase energy expenditure, thereby countering against obesity and its metabolic complications. Given this, agents capable of inducing WAT browning have recently attracted broad attention from biomedical, nutritional and pharmaceutical societies. In this review, we summarize natural bioactive compounds that have been shown to promote beige adipocyte recruitment and activation in animals and cultured cells. We also discuss potential molecular mechanisms for each compound to induce adipose browning and metabolic benefits.

Natural Extracts to Augment Energy Expenditure as a Complementary Approach to Tackle Obesity and Associated Metabolic Alterations

Obesity is the epidemic of the 21st century. In developing countries, the prevalence of obesity continues to rise, and obesity is occurring at younger ages. Obesity and associated metabolic stress disrupt the whole-body physiology. Adipocytes are critical components of the systemic metabolic control, functioning as an endocrine organ. The enlarged adipocytes during obesity recruit macrophages promoting chronic inflammation and insulin resistance. Together with the genetic susceptibility (single nucleotide polymorphisms, SNP) and metabolic alterations at the molecular level, it has been highlighted that key modifiable risk factors, such as those related to lifestyle, contribute to the development of obesity. In this scenario, urgent therapeutic options are needed, including not only pharmacotherapy but also nutrients, bioactive compounds, and natural extracts to reverse the metabolic alterations associated with obesity. Herein, we first summarize the main targetable processes to tackle obesity, including activation of thermogenesis in brown adipose tissue (BAT) and in white adipose tissue (WAT-browning), and the promotion of energy expenditure and/or fatty acid oxidation (FAO) in muscles. Then, we perform a screening of 20 natural extracts (EFSA approved) to determine their potential in the activation of FAO and/or thermogenesis, as well as the increase in respiratory capacity. By means of innovative technologies, such as the study of their effects on cell bioenergetics (Seahorse bioanalyzer), we end up with the selection of four extracts with potential application to ameliorate the deleterious effects of obesity and the chronic associated inflammation.

Associations of Circulating Irisin with FNDC5 Expression in Fat and Muscle in Type 1 and Type 2 Diabetic Mice

Irisin is an exercise-induced myokine, suggested to exert beneficial effects on metabolism. However, the studies on the regulation of irisin secretion and the expression of its precursor FNDC5 have shown conflicting data. The discrepancies among previous correlation studies in humans are related to the heterogeneity of the study population. The fact that irisin is not only a myokine but also an adipokine leads to the further complexity of the role of irisin in metabolic regulation. In this study, we examined the regulation of FNDC5 expression and irisin in circulation in both type 1 and type 2 diabetic mice, and their potential relationships with metabolic parameters. In streptozotocin (STZ)-induced type 1 diabetic mice, high-fat diet (HFD)-induced obese mice and db/db mice, the circulating irisin as well as FNDC5 gene expression in subcutaneous fat was downregulated. Muscle FNDC5 expression was only significantly lower in STZ mice, and epididymal fat FNDC5 expression was unaltered. It is interesting to note that plasma irisin levels correlated positively with subcutaneous fat FNDC5 expression, but not epididymal fat or muscle. Moreover, both irisin levels and subcutaneous fat FNDC5 correlated negatively with markers of insulin resistance. These results suggest a regulatory role for subcutaneous fat-derived FNDC5/irisin in metabolic disease.

Precision Nutrition to Activate Thermogenesis as a Complementary Approach to Target Obesity and Associated-Metabolic-Disorders

Simple Summary

Regarding the pandemic of obesity and chronic diseases associated to metabolic alterations that occur nowadays worldwide, here, we review the most recent studies related to bioactive compounds and diet derived ingredients with potential effects to augment the systemic energy expenditure. We specifically focus in two processes: the activation of thermogenesis in adipose tissue and the enhancement of the mitochondrial oxidative phosphorylation capacity in muscles. This may provide relevant information to develop diets and supplements to conduct nutritional intervention studies with the objective to ameliorate the metabolic and chronic inflammation in the course of obesity and related disorders.

Abstract

Obesity is associated to increased incidence and poorer prognosis in multiple cancers, contributing to up to 20% of cancer related deaths. These associations are mainly driven by metabolic and inflammatory changes in the adipose tissue during obesity, which disrupt the physiologic metabolic homeostasis. The association between obesity and hypercholesterolemia, hypertension, cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) is well known. Importantly, the retrospective analysis of more than 1000 epidemiological studies have also shown the positive correlation between the excess of fatness with the risk of cancer. In addition, more important than weight, it is the dysfunctional adipose tissue the main driver of insulin resistance, metabolic syndrome and all cause of mortality and cancer deaths, which also explains why normal weight individuals may behave as “metabolically unhealthy obese” individuals. Adipocytes also have direct effects on tumor cells through paracrine signaling. Downregulation of adiponectin and upregulation of leptin in serum correlate with markers of chronic inflammation, and crown like structures (CLS) associated to the adipose tissue disfunction. Nevertheless, obesity is a preventable risk factor in cancer. Lifestyle interventions might contribute to reduce the adverse effects of obesity. Thus, Mediterranean diet interventional studies have been shown to reduce to circulation inflammatory factors, insulin sensitivity and cardiovascular function, with durable responses of up to 2 years in obese patients. Mediterranean diet supplemented with extra-virgin olive oil reduced the incidence of breast cancer compared with a control diet. Physical activity is another important lifestyle factor which may also contribute to reduced systemic biomarkers of metabolic syndrome associated to obesity. In this scenario, precision nutrition may provide complementary approaches to target the metabolic inflammation associated to “unhealthy obesity”. Herein, we first describe the different types of adipose tissue -thermogenic active brown adipose tissue (BAT) versus the energy storing white adipose tissue (WAT). We then move on precision nutrition based strategies, by mean of natural extracts derived from plants and/or diet derived ingredients, which may be useful to normalize the metabolic inflammation associated to “unhealthy obesity”. More specifically, we focus on two axis: (1) the activation of thermogenesis in BAT and browning of WAT; (2) and the potential of augmenting the oxidative capacity of muscles to dissipate energy. These strategies may be particularly relevant as complementary approaches to alleviate obesity associated effects on chronic inflammation, immunosuppression, angiogenesis and chemotherapy resistance in cancer. Finally, we summarize main studies where plant derived extracts, mainly, polyphenols and flavonoids, have been applied to increase the energy expenditure.

The "irisin system": From biological roles to pharmacological and nutraceutical perspectives

The scientific interest in irisin, a myokine discovered in 2012, has grown exponentially in recent years. Irisin, which is mainly produced in skeletal muscle, influences the browning process of adipose tissue and lipid and energy metabolism. Recent discoveries highlight that the potential of this hormone may have been underestimated. In the first part of this review, reports on irisin structure and molecules involved in its metabolic pathway are shown. Furthermore, data related to unclear aspects are also reported: distribution, different gene expression of its precursors in different tissues, physiological levels of circulating irisin, and pharmacokinetic and pharmacodynamic profile. The second part of this work focuses on exogenous stimuli and pharmacological agents which regulate the metabolic pathway of irisin and its serum concentration. In addition to physical exercise and exposure to low temperatures, which were early recognized as exogenous stimuli able to promote the production of this myokine, preclinical and clinical evidence demonstrates the ability of natural and synthetic molecules to interfere with this metabolic pathway. Current experimental data on irisin cannot dissolve all doubts related to this interesting molecule, but they certainly underline its potential for therapeutic purposes. Thus, identification of new pharmacological tools able to act on the irisin pathway is a challenging issue for biomedical research.

Recent developments in natural products for white adipose tissue browning

Excess accumulation of white adipose tissue (WAT) causes obesity which is an imbalance between energy intake and energy expenditure. Obesity is a serious concern because it has been the leading causes of death worldwide, including diabetes, stroke, heart disease and cancer. Therefore, uncovering the mechanism of obesity and discovering anti-obesity drugs are crucial to prevent obesity and its complications. Browning, inducing white adipose tissue to brown or beige (brite) fat which is brown-like fat emerging in WAT, becomes an appealing therapeutic strategy for obesity and metabolic disorders. Due to lack of efficacy or intolerable side-effects, the clinical trials that promote brown adipose tissue (BAT) thermogenesis and browning of WAT have not been successful in humans. Obviously, more specific means still need to be developed to activate browning of white adipose tissue. In this review, we summarized seven kinds of natural products (alkaloids, flavonoids, terpenoids, long chain fatty acids, phenolic acids, else and extract) promoting white adipose tissue browning which can ameliorate the metabolic disorders, including obesity, dislipidemia, insulin resistance and diabetes. Since natural products are important drug sources and the browning property plays a significant role in not only obesity treatment but also in type 2 diabetes (T2DM) improvement, natural products of inducing browning may be an irreplaceable drug discovery orientation for obesity, diabetes and even other metabolic disorders.

Dietary polyphenols in lipid metabolism: A role of gut microbiome

Polyphenols are a class of non-essential phytonutrients, which are abundant in fruits and vegetables. Dietary polyphenols or foods rich in polyphenols are widely recommended for metabolic health. Indeed, polyphenols (i.e., catechins, resveratrol, and curcumin) are increasingly recognized as a regulator of lipid metabolism in host. The mechanisms, at least in part, may be highly associated with gut microbiome. This review mainly discussed the beneficial effects of dietary polyphenols on lipid metabolism. The potential mechanisms of gut microbiome are focused on the effect of dietary polyphenols on gut microbiota compositions and how gut microbiota affect polyphenol metabolism. Together, dietary polyphenols may be a useful nutritional strategy for manipulation of lipid metabolism or obesity care.

Grape pomace extract supplementation activates FNDC5/irisin in muscle and promotes white adipose browning in rats fed a high-fat diet

Irisin is a myokine regulated by peroxisome proliferator-activated receptor gamma co-activator-1α (PGC-1α) in the exercising skeletal muscle and released into the bloodstream after cleavage of FNDC5. Circulating irisin can up-regulate UCP-1 expression in white adipose tissue (WAT) promoting the formation of brown-like adipocytes. The aim of this study was to evaluate if supplementation with a grape pomace extract (GPE) could activate the FNDC5/irisin pathway via PGC-1α in rats fed a high fat diet (HFD). For this purpose we characterized the activation of: i. the FNDC5/irisin pathway and AMPK in skeletal muscle and ii. proteins involved in the formation of brown-like cells in epididymal WAT (eWAT). Consumption of the GPE activated the FNDC5/irisin pathway, increased AMPK phosphorylation in skeletal muscle and enhanced irisin plasma levels. In eWAT, the GPE increased the level of proteins involved in WAT browning, i.e. PGC-1α, PPARγ, PRDM16 and UCP-1. The GPE also prevented HFD-induced adipocyte hypertrophy and systemic insulin resistance. Consistently, in L6 myotubes, (-)-epicatechin (EC), a flavonoid abundant in the GPE, prevented palmitate-mediated downregulation of FNDC5/irisin protein expression and secretion, in part via PGC-1α activation. Consumption of the GPE, a winemaking residue rich in bioactive compounds, could be a beneficial strategy to counteract the adverse effects of Western style diets through the promotion of WAT browning.

Induction of Adipose Tissue Browning as a Strategy to Combat Obesity

The ongoing obesity pandemic generates a constant need to develop new therapeutic strategies to restore the energy balance. Therefore, the concept of activating brown adipose tissue (BAT) in order to increase energy expenditure has been revived. In mammals, two developmentally distinct types of brown adipocytes exist; the classical or constitutive BAT that arises during embryogenesis, and the beige adipose tissue that is recruited postnatally within white adipose tissue (WAT) in the process called browning. Research of recent years has significantly increased our understanding of the mechanisms involved in BAT activation and WAT browning. They also allowed for the identification of critical molecules and critical steps of both processes and, therefore, many new therapeutic targets. Several non-pharmacological approaches, as well as chemical compounds aiming at the induction of WAT browning and BAT activation, have been tested in vitro as well as in animal models of genetically determined and/or diet-induced obesity. The therapeutic potential of some of these strategies has also been tested in humans. In this review, we summarize present concepts regarding potential therapeutic targets in the process of BAT activation and WAT browning and available strategies aiming at them.

Recent Advances in Nanoencapsulation of Phytochemicals to Combat Obesity and Its Comorbidities

An increasing epidemic of obesity has become a serious public health concern primarily because it contributes to pathogenesis of many chronic diseases including type 2 diabetes, cardiovascular disease, hepatobiliary disease, obstructive sleep apnea, kidney disease, some types of cancer, among others. Consumption of a variety of phytochemicals has emerged as a promising potential for combating obesity and its comorbidities. However, the generally low aqueous solubility, stability, bioavailability, and target specificity of phytochemicals, along with their side-effects and toxicity seen when used at high doses, have restricted their clinical applications. As a solution, phytochemicals can be encapsulated into nanoparticles to increase their stability and solubility, enhance their bioavailability, protect them from premature degradation in the body, prolong their circulation time, and thus enhance their antiobesity activity. In this perspective, we summarize the problems and limitations of the prominent phytochemicals (epigallocatechin gallate, trans-resveratrol, curcumin, and quercetin), the major biocompatible and biodegradable nanoparticles, and the efficacy of nanoencapsulated forms of these phytochemicals in combating obesity and its comorbidities.

Sirtuins, brain and cognition: A review of resveratrol effects

Sirtuins (SIRTs) are a protein family with high preservation degree among evolutionary scale. SIRTs are histone deacetylases regulatory enzymes of genetic material deeply involved in numerous physiological tasks including metabolism, brain function and aging. Mammals sirtuins comprise seven enzymatic components (SIRT1–SIRT7). The highest studied sirtuin is SIRT1, which plays an essential position in the prevention and evolution of neuro-disorders. Resveratrol (3,5,4-trihydroxystylbene) (RSV) is a polyphenol, which belongs to a family compounds identified as stilbenes, predominantly concentrated in grapes and red wine. RSV is the must studied Sirtuin activator and is used as food supplementary compound. Resveratrol exhibits strong antioxidant activity, reducing free radicals, diminishing quinone-reductase-2 activity and exerting positive regulation of several endogenous enzymes. Resveratrol is also able to inhibit pro-inflammatory factors, reducing the stimulation of the nuclear factor kB (NF-kB) and the release of endogenous cytokines. Resveratrol treatment can modulate multiple signaling pathway effectors related to programmed cell death, cell survival, and synaptic plasticity. In this context, the present review looks over news and the role of Sirtuins activation and resveratrol effects on modulating target genes, cognition and neurodegenerative disorders.

Polyphenols and obesity prevention: critical insights on molecular regulation, bioavailability and dose in preclinical and clinical settings

Obesity represents one of the most important public health challenges of the 21st century and is characterized by a multifactorial etiology in which environmental, behavioral, metabolic, and genetic factors work together. Despite the rapid increase in prevalence of obesity in the last decades, especially in children, it remains a preventable disease. To battle obesity a multisector approach promoting healthier lifestyle in terms of physical activity and nutrition is needed. Specifically, biologically active dietary compounds, as polyphenols, are able to modulate the expression of genes involved in the development and progression of obesity and its comorbidities as demonstrated by multiple studies using different obesity models. However, human studies focusing on the transcriptomic modulation by polyphenols in obese patients are still limited and do not often recapitulate the results obtained in preclinical setting likely due to the underestimation of some variables such as bioavailability, dose and form (native vs. metabolized) of polyphenols used. The aim of this review is to summarize the state-of-art of nutrigenomic in vitro, in vivo and ex vivo studies as well as clinical trials based on dietary polyphenols to fight obesity. We also critical discuss the variables to be considered to fill the gap between preclinical and clinical settings.

Effects of resveratrol and its derivative pterostilbene on brown adipose tissue thermogenic activation and on white adipose tissue browning process

The main function of brown adipose tissue (BAT) is thermogenesis, a process mediated by uncoupling protein 1 (UCP1), which is located in the inner mitochondrial membrane and acts uncoupling oxidative phosphorylation from ATP production, thereby dissipating energy as heat. White adipose tissue can also express UCP1 positive cells due to a process known as browning. This phenomenon could also increase the thermogenic effect in the classical brown adipose depots. BAT thermogenesis depends, among other factors on both, nutritional conditions and food availability. Indeed, some studies have found that BAT recruitment and function are enhanced by some food components. The present study focuses on the effects of resveratrol and pterostilbene, two phenolic compounds belonging to the stilbene group, on BAT thermogenic activation and white adipose tissue browning process. The reported studies, carried out in cell cultures and animal models, show that both resveratrol and pterostilbene induce thermogenic capacity in interscapular BAT by increasing mitochondriogenesis, as well as enhancing fatty acid oxidation and glucose disposal. In addition, resveratrol seems to promote browning by activating peroxisome proliferator-activated receptor (PPAR), while the lack of changes in mitochondrial biogenesis suggests that probably the browning process occurs by direct resveratrol-mediated upregulation of ucp1 mRNA expression.

Resveratrol-induced brown fat-like phenotype in 3T3-L1 adipocytes partly via mTOR pathway

Background

Browning of white adipose tissues (WAT) is recognized as a novel way to combat obesity and its related comorbidities. Thus, a lot of dietary agents contributing to browning of WAT have been identified.

Objective

In this study, we try to explore the mechanism of the browning of WAT induced by resveratrol (Res) in 3T3-L1 adipocytes.

Methods

The levels of cell viability and lipid accumulation were evaluated under different concentrations of Res. Cell signaling pathway analysis was performed to investigate the possible mechanisms of the WAT browning effect of Res in 3T3-L1 cells.

Results

We found that Res induced the brown fat-like phenotype by activating protein expressions of brown adipocyte-specific markers, such as peroxisome proliferator-activated receptor gamma (PPAR-γ), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and uncoupling protein 1 (UCP1). Besides, Res reduced lipid accumulation, as shown by Oil Red O staining. The increased small lipid droplets implied that Res-treated 3T3-L1 adipocytes had some features of brown adipocytes. The brown fat-like phenotype in 3T3-L1 adipocytes induced by Res was possibly mediated by activation of mammalian target of rapamycin (mTOR), as brown adipocyte-specific markers were decreased by rapamycin, an inhibitor of mTOR and the MHY1485 treatment, an activator of mTOR, showed the similar effect of Res on browning markers.

Conclusions

Res induced brown-like adipocyte phenotype in 3T3-L1 adipocytes partly via mTOR pathway, which provided new insights into the utilization of Res to prevent obesity and related comorbidities.

Resveratrol and Oxyresveratrol Activate Thermogenesis via Different Transcriptional Coactivators in High-Fat Diet-Induced Obese Mice

Obesity is a global public health issue. Thermogenesis is a novel way to promote anti-obesity by consuming energy as heat rather than storing it as triacylglycerols. The browning program allows mitochondrial biosynthesis and thermogenesis-related gene expression to occur in subcutaneous white adipose tissue, which results in the formation of beige adipose tissue. Some phytochemicals have exerted the capability to activate the fat browning process. Resveratrol and oxyresveratrol are both natural stilbenoids that have been reported for their anti-obesity efficacy. However, the comparison between the two as they relate to thermogenesis as well as the differences in their underlying mechanisms are still not widely discussed. Our result reveals that both resveratrol and oxyresveratrol could elevate the expression of thermogenesis-related protein expression including UCP1 (uncoupling protein-1) and PRDM (PR domain containing 16) via Sirt1/PGC-1α (sirtuin 1/peroxisome proliferation gamma coactivator-1 α) activation. However, it is suggested that the transcriptional factor PPARα (peroxisome proliferator-activator receptor α) was activated by resveratrol (1.38 ± 0.07 fold) but not oxyresveratrol. Conversely, C/EBPβ (CCAAT/enhancer-binding protein β) was upregulated by oxyresveratrol (1.58 ± 0.05 fold) but not by resveratrol. On the other hand, CPT1 (carnitine palmitoyltransferase) was found to be significantly activated at lower concentrations of oxyresveratrol up to 1.89 ± 0.04 fold as compared to high-fat diet, and it could be a leading reason for UCP1 activation. Lastly, adiponectin expression was promoted in all experimental groups (1.53 ± 0.08 and 1.49 ± 0.11-fold in resveratrol (RES) and high oxyresveratrol (HOXY), respectively), which could be an activator for mitochondrial biosynthesis and UCP1 expression.

Oral gallic acid improves metabolic profile by modulating SIRT1 expression in obese mice brown adipose tissue: A molecular and bioinformatic approach

AIMS

The aim of the presente study was to examine the effects of oral gallic acid (GA) administration on the brown adipose tissue of obese mice fed with high-fat diet. New mechanisms and interactions pathways in thermogenesis were accessed through bioinformatics analyses.

MAIN METHODS

Swiss male mice were divided into four groups and fed during 60 days with: standard diet, standard diet combined with gallic acid, high-fat diet and high-fat diet combined with gallic acid. Body weight, food intake, and blood parameters (glucose tolerance test, total-cholesterol, high-density low-c, triglyceride and glucose levels) were evaluated. Brown and subcutaneous white adipose tissue histological analysis were performed. SIRT1 and PGC1-α mRNA expression in the brown adipose tissue were assessed.

KEY FINDINGS

Our main findings showed that the gallic acid improved glucose tolerance and metabolic parameters. These results were accompanied by bioinformatics analyses that evidenced SIRT1 as main target in the thermogenesis process, confirmed as increased SIRT1 mRNA expression was evidenced in the brown adipose tissue.

SIGNIFICANCE

Together, the data suggest that the gallic acid effect in brown adipose tissue may improve body metabolism, glucose homeostasis and increase thermogenesis.

Natural constituents from food sources: potential therapeutic agents against muscle wasting

Skeletal muscle wasting is highly correlated with not only reduced quality of life but also higher morbidity and mortality. Although an increasing number of patients are suffering from various kinds of muscle atrophy and weakness, there is still no effective therapy available, and skeletal muscle is considered as an under-medicated organ. Food provided not only essential macronutrients but also functional substances involved in the modulation of the physiological systems of our body. Natural constituents from commonly consumed dietary plants, either extracts or compounds, have attracted more and more attention to be developed as agents for preventing and treating muscle wasting due to their safety and effectiveness, as well as structural diversity. This review provides an overview of the mechanistic aspects of muscle wasting, and summarizes the extracts and compounds from food sources as potential therapeutic agents against muscle wasting.

Effect of resveratrol on adipokines and myokines involved in fat browning: Perspectives in healthy weight against obesity

Obesity is a globally widespread metabolic disorder, characterized by immoderate fat accumulation in the body. There are different types of body fats such as white adipose tissue (WAT), which stores surplus energy in the body, and brown adipose tissue (BAT) which utilize energy to produce heat during metabolism. BAT acts many beneficial functions in metabolic disorders including type 2 diabetes and obesity. Recent studies have investigated methods for promoting the fat browning process of WAT in obesity because of various reasons such as the improvement of insulin resistance, and weight loss. Among natural polyphenolic compounds, resveratrol has been highlighted due to its anti-oxidant and anti-obesity as well as anti-inflammation and anti-cancer properties. Recent studies have paid a lot of attention to that resveratrol may act as a fat browning activator, involved in the secretion of many myokines and adipokines. Here, we reviewed the role of resveratrol in fat browning and also the association between resveratrol and adipokines/myokines in the fat browning process. Our review may provide novel insight into the role of resveratrol in fat browning, leading to the maintenance of a healthy weight against obesity.