Resveratrol increases brown adipose tissue thermogenesis markers by increasing SIRT1 and energy expenditure and decreasing fat accumulation in adipose tissue of mice fed a standard diet

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.

Molecular Regulation of Thermogenic Mechanisms in Beige Adipocytes

Adipose tissue is conventionally recognized as a metabolic organ responsible for storing energy. However, a proportion of adipose tissue also functions as a thermogenic organ, contributing to the inhibition of weight gain and prevention of metabolic diseases. In recent years, there has been significant progress in the study of thermogenic fats, particularly brown adipose tissue (BAT). Despite this progress, the mechanism underlying thermogenesis in beige adipose tissue remains highly controversial. It is widely acknowledged that beige adipose tissue has three additional thermogenic mechanisms in addition to the conventional UCP1-dependent thermogenesis: Ca2+ cycling thermogenesis, creatine substrate cycling thermogenesis, and triacylglycerol/fatty acid cycling thermogenesis. This paper delves into these three mechanisms and reviews the latest advancements in the molecular regulation of thermogenesis from the molecular genetic perspective. The objective of this review is to provide readers with a foundation of knowledge regarding the beige fats and a foundation for future research into the mechanisms of this process, which may lead to the development of new strategies for maintaining human health.

The Effects of Antioxidant Supplementation on the Pathologic Mechanisms of Metabolic Syndrome and Cardiovascular Disease Development

In people with obesity, diabetes, and hypertension, lipid and glucose metabolism and oxidative stress generation interact. This condition, known as a "metabolic syndrome" (MetS), presents a global challenge and appears to be the underlying mechanism for the development of cardiovascular diseases (CVDs). This review is designed based on evidence indicating the pathogenic mechanisms of MetS. In detail, we will look at the mechanisms of oxidative stress induction in MetS, the effects of elevated oxidative stress levels on the condition's pathophysiology, and matters related to endothelial function. According to different components of the MetS pathophysiological network, the effects of antioxidants and endothelial dysfunction are reviewed. After considering the strategic role of oxidative stress in the pathophysiology of MetS and its associated CVDs, oxidative stress management by antioxidant supplementation seems an appropriate therapeutic approach.

Guanidinoacetic acid ameliorates hepatic steatosis and inflammation and promotes white adipose tissue browning in middle-aged mice with high-fat-diet-induced obesity

Guanidinoacetic acid (GAA) is a naturally occurring amino acid derivative that plays a critical role in energy metabolism. In recent years, a growing body of evidence has emerged supporting the importance of GAA in metabolic dysfunction. Hence, we aimed to investigate the effects of GAA on hepatic and adipose tissue metabolism, as well as systemic inflammatory responses in obese middle-aged mice models and attempted to explore the underlying mechanism. We found that dietary supplementation of GAA inhibited inguinal white adipose tissue (iWAT) hypertrophy in high-fat diet (HFD)-fed mice. In addition, GAA supplementation observably decreased the levels of some systemic inflammatory factors, including IL-4, TNF-α, IL-1β, and IL-6. Intriguingly, GAA supplementation ameliorated hepatic steatosis and lipid deposition in HFD-fed mice, which was revealed by decreased levels of TG, TC, LDL-C, PPARγ, SREBP-1c, FASN, ACC, FABP1, and APOB and increased levels of HDL-C in the liver. Moreover, GAA supplementation increased the expression of browning markers and mitochondrial-related genes in the iWAT. Further investigation showed that dietary GAA promoted the browning of the iWAT via activating the AMPK/Sirt1 signaling pathway and might be associated with futile creatine cycling in obese mice. These results indicate that GAA has the potential to be used as an effective ingredient in dietary interventions and thus may play an important role in ameliorating and preventing HFD-induced obesity and related metabolic diseases.

Physiological Approaches Targeting Cellular and Mitochondrial Pathways Underlying Adipose Organ Senescence

The adipose organ is involved in many metabolic functions, ranging from the production of endocrine factors to the regulation of thermogenic processes. Aging is a natural process that affects the physiology of the adipose organ, leading to metabolic disorders, thus strongly impacting healthy aging. Cellular senescence modifies many functional aspects of adipose tissue, leading to metabolic alterations through defective adipogenesis, inflammation, and aberrant adipocytokine production, and in turn, it triggers systemic inflammation and senescence, as well as insulin resistance in metabolically active tissues, leading to premature declined physiological features. In the various aging fat depots, senescence involves a multiplicity of cell types, including mature adipocytes and immune, endothelial, and progenitor cells that are aging, highlighting their involvement in the loss of metabolic flexibility, one of the common features of aging-related metabolic disorders. Since mitochondrial stress represents a key trigger of cellular senescence, and senescence leads to the accumulation of abnormal mitochondria with impaired dynamics and hindered homeostasis, this review focuses on the beneficial potential of targeting mitochondria, so that strategies can be developed to manage adipose tissue senescence for the treatment of age-related metabolic disorders.

Acteoside improves adipocyte browning by CDK6-mediated mTORC1-TFEB pathway

Adipocyte browning increases energy expenditure by thermogenesis, which has been considered a potential strategy against obesity and its related metabolic diseases. Phytochemicals derived from natural products with the ability to improve adipocyte thermogenesis have aroused extensive attention. Acteoside (Act), a phenylethanoid glycoside, exists in various medicinal or edible plants and has been shown to regulate metabolic disorders. Here, the browning effect of Act was evaluated by stimulating beige cell differentiation from the stromal vascular fraction (SVF) in the inguinal white adipose tissue (iWAT) and 3 T3-L1 preadipocytes, and by converting the iWAT-SVF derived mature white adipocytes. Act improves adipocyte browning by differentiation of the stem/progenitors into beige cells and by direct conversion of mature white adipocytes into beige cells. Mechanistically, Act inhibited CDK6 and mTOR, and consequently relieved phosphorylation of the transcription factor EB (TFEB) and increased its nuclear retention, leading to induction of PGC-1α, a driver of mitochondrial biogenesis, and UCP1-dependent browning. These data thus unveil a CDK6-mTORC1-TFEB pathway that regulates Act-induced adipocyte browning.

The Influence of Antioxidants on Oxidative Stress-Induced Vascular Aging in Obesity

Obesity is a worldwide trend that is growing in incidence very fast. Adipose tissue dysfunction caused by obesity is associated with the generation of oxidative stress. Obesity-induced oxidative stress and inflammation play a key role in the pathogenesis of vascular diseases. Vascular aging is one of the main pathogenesis mechanisms. The aim of this study is to review the effect of antioxidants on vascular aging caused by oxidative stress in obesity. In order to achieve this aim, this paper is designed to review obesity-caused adipose tissue remodeling, vascular aging generated by high levels of oxidative stress, and the effects of antioxidants on obesity, redox balance, and vascular aging. It seems that vascular diseases in obese individuals are complex networks of pathological mechanisms. In order to develop a proper therapeutic tool, first, there is a need for a better understanding of interactions between obesity, oxidative stress, and aging. Based on these interactions, this review suggests different lines of strategies that include change in lifestyle to prevent and control obesity, strategies for adipose tissue remodelling, oxidant-antioxidant balance, inflammation suppression, and strategies against vascular aging. Some antioxidants support different lines of these strategies, making them appropriate for complex conditions such as oxidative stress-induced vascular diseases in obese individuals.

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.

Influence of Polyphenols on Adipose Tissue: Sirtuins as Pivotal Players in the Browning Process

Adipose tissue (AT) can be classified into two different types: (i) white adipose tissue (WAT), which represents the largest amount of total AT, and has the main function of storing fatty acids for energy needs and (ii) brown adipose tissue (BAT), rich in mitochondria and specialized in thermogenesis. Many exogenous stimuli, e.g., cold, exercise or pharmacological/nutraceutical tools, promote the phenotypic change of WAT to a beige phenotype (BeAT), with intermediate characteristics between BAT and WAT; this process is called "browning". The modulation of AT differentiation towards WAT or BAT, and the phenotypic switch to BeAT, seem to be crucial steps to limit weight gain. Polyphenols are emerging as compounds able to induce browning and thermogenesis processes, potentially via activation of sirtuins. SIRT1 (the most investigated sirtuin) activates a factor involved in mitochondrial biogenesis, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), which, through peroxisome proliferator-activated receptor γ (PPAR-γ) modulation, induces typical genes of BAT and inhibits genes of WAT during the transdifferentiation process in white adipocytes. This review article aims to summarize the current evidence, from pre-clinical studies to clinical trials, on the ability of polyphenols to promote the browning process, with a specific focus on the potential role of sirtuins in the pharmacological/nutraceutical effects of natural compounds.

Browning of Adipocytes: A Potential Therapeutic Approach to Obesity

The increasing prevalence of overweight and obesity suggests that current strategies based on diet, exercise, and pharmacological knowledge are not sufficient to tackle this epidemic. Obesity results from a high caloric intake and energy storage, the latter by white adipose tissue (WAT), and when neither are counterbalanced by an equally high energy expenditure. As a matter of fact, current research is focused on developing new strategies to increase energy expenditure. Against this background, brown adipose tissue (BAT), whose importance has recently been re-evaluated via the use of modern positron emission techniques (PET), is receiving a great deal of attention from research institutions worldwide, as its main function is to dissipate energy in the form of heat via a process called thermogenesis. A substantial reduction in BAT occurs during normal growth in humans and hence it is not easily exploitable. In recent years, scientific research has made great strides and investigated strategies that focus on expanding BAT and activating the existing BAT. The present review summarizes current knowledge about the various molecules that can be used to promote white-to-brown adipose tissue conversion and energy expenditure in order to assess the potential role of thermogenic nutraceuticals. This includes tools that could represent, in the future, a valid weapon against the obesity epidemic.

Thermogenic adipose tissue in energy regulation and metabolic health

The ability to generate thermogenic fat could be a targeted therapy to thwart obesity and improve metabolic health. Brown and beige adipocytes are two types of thermogenic fat cells that regulate energy balance. Both adipocytes share common morphological, biochemical, and thermogenic properties. Yet, recent evidence suggests unique features exist between brown and beige adipocytes, such as their cellular origin and thermogenic regulatory processes. Beige adipocytes also appear highly plastic, responding to environmental stimuli and interconverting between beige and white adipocyte states. Additionally, beige adipocytes appear to be metabolically heterogenic and have substrate specificity. Nevertheless, obese and aged individuals cannot develop beige adipocytes in response to thermogenic fat-inducers, creating a key clinical hurdle to their therapeutic promise. Thus, elucidating the underlying developmental, molecular, and functional mechanisms that govern thermogenic fat cells will improve our understanding of systemic energy regulation and strive for new targeted therapies to generate thermogenic fat. This review will examine the recent advances in thermogenic fat biogenesis, molecular regulation, and the potential mechanisms for their failure.

A Novel Mix of Polyphenols and Micronutrients Reduces Adipogenesis and Promotes White Adipose Tissue Browning via UCP1 Expression and AMPK Activation

Background: Obesity is a pandemic disease characterized by excessive severe body comorbidities. Reduction in fat accumulation represents a mechanism of prevention, and the replacement of white adipose tissue (WAT) with brown adipose tissue (BAT) has been proposed as one promising strategy against obesity. In the present study, we sought to investigate the ability of a natural mixture of polyphenols and micronutrients (A5⁺) to counteract white adipogenesis by promoting WAT browning. Methods: For this study, we employed a murine 3T3-L1 fibroblast cell line treated with A5⁺, or DMSO as control, during the differentiation in mature adipocytes for 10 days. Cell cycle analysis was performed using propidium iodide staining and cytofluorimetric analysis. Intracellular lipid contents were detected by Oil Red O staining. Inflammation Array, along with qRT-PCR and Western Blot analyses, served to measure the expression of the analyzed markers, such as pro-inflammatory cytokines. Results: A5⁺ administration significantly reduced lipids' accumulation in adipocytes when compared to control cells (p < 0.005). Similarly, A5⁺ inhibited cellular proliferation during the mitotic clonal expansion (MCE), the most relevant stage in adipocytes differentiation (p < 0.0001). We also found that A5⁺ significantly reduced the release of pro-inflammatory cytokines, such as IL-6 and Leptin (p < 0.005), and promoted fat browning and fatty acid oxidation through increasing expression levels of genes related to BAT, such as UCP1 (p < 0.05). This thermogenic process is mediated via AMPK-ATGL pathway activation. Conclusion: Overall, these results demonstrated that the synergistic effect of compounds contained in A5⁺ may be able to counteract adipogenesis and then obesity by inducing fat browning.

Brown Adipose Tissue Transplantation

The metabolic benefits of brown adipose tissue (BAT) are well known. Increasing the BAT content and/or activity is a proposed therapeutic approach to combat metabolic disease. Activation and induction of endogenous BAT have achieved varying degrees of success in correcting obesity, insulin resistance, and cardiovascular disease, with some limitations. Transplantation of BAT from healthy donors is another approach proven safe and effective in rodent models. In diet-induced models of obesity and insulin resistance, BAT transplants prevent obesity, increase insulin sensitivity, and improve glucose homeostasis and whole-body energy metabolism. In mouse models of insulin-dependent diabetes, subcutaneous transplantation of healthy BAT produces long-term euglycemia without the need for insulin or immunosuppression. Considering the immunomodulatory and anti-inflammatory properties of healthy BAT, transplantation may be a more effective approach to combat metabolic disease in the long term. Here we describe in detail the technique for subcutaneous BAT transplantation.

Bioactive dietary components-Anti-obesity effects related to energy metabolism and inflammation

Obesity is the result of the long-term energy imbalance between the excess calories consumed and the few calories expended. Reducing the intake of energy dense foods (fats, sugars), and strategies such as fasting and caloric restriction can promote body weight loss. Not only energy in terms of calories, but also the specific composition of the diet can affect the way the food is absorbed and how its energy is stored, used or dissipated. Recent research has shown that bioactive components of food, such as polyphenols and vitamins, can influence obesity and its pathologic complications such as insulin resistance, inflammation and metabolic syndrome. Individual micronutrients can influence lipid turnover but for long-term effects on weight stability, dietary patterns containing several micronutrients may be required. At the molecular level, these molecules modulate signaling and the expression of genes that are involved in the regulation of energy intake, lipid metabolism, adipogenesis into white, beige and brown adipose tissue, thermogenesis, lipotoxicity, adipo/cytokine synthesis, and inflammation. Higher concentrations of these molecules can be reached in the intestine, where they can modulate the composition and action of the microbiome. In this review, the molecular mechanisms by which bioactive compounds and vitamins modulate energy metabolism, inflammation and obesity are discussed.

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.

Factors Associated with White Fat Browning: New Regulators of Lipid Metabolism

Mammalian adipose tissue can be divided into white and brown adipose tissue based on its colour, location, and cellular structure. Certain conditions, such as sympathetic nerve excitement, can induce the white adipose adipocytes into a new type of adipocytes, known as beige adipocytes. The process, leading to the conversion of white adipocytes into beige adipocytes, is called white fat browning. The dynamic balance between white and beige adipocytes is closely related to the body’s metabolic homeostasis. Studying the signal transduction pathways of the white fat browning might provide novel ideas for the treatment of obesity and alleviation of obesity-related glucose and lipid metabolism disorders. This article aimed to provide an overview of recent advances in understanding white fat browning and the role of BAT in lipid metabolism.

A Review on Rhubarb-Derived Substances as Modulators of Cardiovascular Risk Factors—A Special Emphasis on Anti-Obesity Action

The currently available anti-obesity therapies encounter many associated risks and side effects often causing the ineffectiveness of treatment. Therefore, various plant-derived substances have been extensively studied as a promising support or even an alternative for existing anti-obesity therapies. This review is dealing with the anti-obesity potential of edible and ethnomedicinal rhubarb species and emerging possible role of the rhubarb-derived extracts or individual compounds in the prevention of obesity and perspectives for their use in an anti-obesity treatment. A special emphasis is put on the most popular edible specimens, i.e., Rheum rhabarbarum L. (garden rhubarb) and Rheum rhaponticum L. (rhapontic rhubarb, Siberian rhubarb); however, the anti-obesity potential of other rhubarb species (e.g., R. officinale, R. palmatum, and R. emodi) is presented as well. The significance of rhubarb-derived extracts and low-molecular specialized rhubarb metabolites of diversified chemical background, e.g., anthraquinones and stilbenes, as potential modulators of human metabolism is highlighted, including the context of cardiovascular disease prevention. The available reports present multiple encouraging rhubarb properties starting from the anti-lipidemic action of rhubarb fibre or its use as purgative medicines, through various actions of rhubarb-derived extracts and their individual compounds: inhibition of enzymes of cholesterol and lipid metabolism, targeting of key molecular regulators of adipogenesis, regulators of cell energy metabolism, the ability to inhibit pro-inflammatory signalling pathways and to regulate glucose and lipid homeostasis contributing to overall in vivo and clinical anti-obesity effects.

An update on brown adipose tissue and obesity intervention: Function, regulation and therapeutic implications

Overweight and obesity have become a world-wide problem. However, effective intervention approaches are limited. Brown adipose tissue, which helps maintain body temperature and contributes to thermogenesis, is dependent on uncoupling protein1. Over the last decade, an in-creasing number of studies have found that activating brown adipose tissue and browning of white adipose tissue can protect against obesity and obesity-related metabolic disease. Brown adipose tissue has gradually become an appealing therapeutic target for the prevention and re-versal of obesity. However, some important issues remain unresolved. It is not certain whether increasing brown adipose tissue activity is the cause or effect of body weight loss or what the risks might be for sympathetic nervous system-dependent non-shivering thermogenesis. In this review, we comprehensively summarize approaches to activating brown adipose tissue and/or browning white adipose tissue, such as cold exposure, exercise, and small-molecule treatment. We highlight the functional mechanisms of small-molecule treatment and brown adipose tissue transplantation using batokine, sympathetic nervous system and/or gut microbiome. Finally, we discuss the causality between body weight loss induced by bariatric surgery, exercise, and brown adipose tissue activity.

Repeated Oral Administration of Flavan-3-ols Induces Browning in Mice Adipose Tissues through Sympathetic Nerve Activation

We previously found increases in uncoupling protein (Ucp)-1 transcription in brown adipose tissue (BAT) of mice following a single oral dose of flavan 3-ol (FL)s, a fraction of catechins and procyanidins. It was confirmed that these changes were totally reduced by co-treatment of adrenaline blockers. According to these previous results, FLs possibly activate sympathetic nervous system (SNS). In this study, we confirmed the marked increase in urinary catecholamine (CA) s projecting SNS activity following a single dose of 50 mg/kg FLs. In addition, we examined the impact of the repeated administration of 50 mg/kg FLs for 14 days on adipose tissues in mice. In BAT, FLs tended to increase the level of Ucp-1 along with significant increase of thermogenic transcriptome factors expressions, such as peroxisome proliferator-activated receptor γ coactivator (PGC)-1α and PR domain-containing (PRDM)1. Expression of browning markers, CD137 and transmembrane protein (TMEM) 26, in addition to PGC-1α were increased in epididymal adipose (eWAT) by FLs. A multilocular morphology with cell size reduction was shown in the inguinal adipose (iWAT), together with increasing the level of Ucp-1 by FLs. These results exert that FLs induce browning in adipose, and this change is possibly produced by the activation of the SNS.

Regulation of Sirt1 on energy metabolism and immune response in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease. Synovial hyperplasia and persistent inflammation serve as its typical pathological manifestations, which ultimately lead to joint destruction and function loss. Both clinical observations and metabolomics studies have revealed the prevalence of metabolic disorders in RA. In inflammatory immune microenvironments, energy metabolism is profoundly changed. Increasingly evidences suggest that this abnormality is involved in the occurrence and development of RA-related inflammation. Unsurprisingly, many energy metabolism sensors have been confirmed with immunoregulatory properties. As a representative, silent information regulator type 1 (Sirt1) controls many aspects of immune cells, such as cell lifespan, polarization, and secretion by functioning as a transcriptional regulator. Because of the profound clinical implication, researches on Sirt1 in the regulation of energy metabolism and immune functions under RA conditions have gradually gained momentum. This signaling balances glycolysis, lipid metabolism and insulin secretion orchestrating with other metabolism sensors, and consequently affects immune milieu through a so-called metabolism-immune feedback mechanism. This article reviews the involvement of Sirt1 in RA by discussing its impacts on energy metabolism and immune functions, and specially highlights the potential of Sirt1-targeting anti-rheumatic regimens. It also provides a theoretical basis for clarifying the mystery about the high incidence of metabolic complications in RA patients and identifying new anti-rheumatic reagents.

Effect of kombucha intake on the gut microbiota and obesity-related comorbidities: A systematic review

Kombucha is a fermented nonalcoholic tea-based beverage produced through a symbiotic culture of bacteria and yeasts. In vitro studies have demonstrated antimicrobial, antioxidant, antiproliferative, and anti-carcinogenic properties of kombucha. However, no systematic reviews have evaluated the effects of kombucha in vivo. Thus, we aimed to evaluate the evidence that exists so far about kombucha consumption on comorbidities associated with obesity as well as on the gut microbiota. The search was conducted in accordance with PRISMA and the protocol was registered in PROSPERO (registration number: CRD42020158917). The MEDLINE/PubMed, Web of Science, LILACS, SciELO, Scopus, and Science Direct databases were used in the search considering the following terms: "kombucha" OR "kombucha tea" OR "kombucha teas" OR "tea, kombucha" OR "teas, kombucha" NOT "review." Fifteen studies were included in this review. The results suggest that kombucha consumption attenuates oxidative stress and inflammation, improves the liver detoxification process, and reduces intestinal dysbiosis. There is evidence that kombucha consumption is beneficial for the control and treatment of obesity and associated comorbidities, as well as for the modulation of the gut microbiota in vivo.

A Standardized Aframomum melegueta Seed Extract Regulates Browning of White Adipose Tissue in High-Fat Diet Model Mice

Thermogenesis-mediated energy expenditure is a promising strategy to combat obesity. Aframomum melegueta commonly known as grains of paradise (GP) is a popular spice with medicinal attributes in promoting health. We have demonstrated the thermogenic effects of a standardized A melegueta seed extract (AMSE) containing not <10% 6-paradol in high fat diet-fed (HFD) mice. The 6-week oral ingestion of 20 and 40 mg/kg AMSE significantly limited the weight gain, improved the brown adipose tissue (BAT) activity in HFD mice. Interestingly, AMSE markedly induced the beige adipocytes in epididymal white adipose tissue (eWAT). AMSE treatment led to the upregulation of marker proteins i.e., uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor-gamma-coactivator 1-alpha (PGC-1α), and peroxisome proliferator-activated receptor gamma (PPARγ) in eWAT and BAT. Our findings add to the current understanding of the thermogenic potentials of GP seed extract and report that the extract can stimulate the browning of WATs in addition to enhanced BAT activity. AMSE requires clinical validation to be explored as a dietary supplement/functional ingredient with thermogenic effect in food and beverages.

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.

Can resveratrol modulate sirtuins in obesity and related diseases? A systematic review of randomized controlled trials

PURPOSE

Human sirtuins can be a powerful therapeutic target in preventing and treating obesity and age-related diseases. Some dietary components can modulate sirtuins' activity, such as resveratrol. This systematic review aimed to assess whether resveratrol (RSV), without other interventions, can stimulate sirtuins in the treatment of excess weight and its comorbidities.

METHODS

MEDLINE/Pubmed, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) were used for search eligible articles. Randomized clinical trials assessing RSV supplementation on changes in the sirtuins' gene expression/protein levels was the primary outcome. Other possible changes in cardiometabolic markers were considered the second outcome. Following PRISMA guidelines and using predefined inclusion and exclusion criteria, two reviewers independently and in parallel screened, assessed the studies' quality, and compiled data. Disagreements were resolved by consensus or consulting a third author.

RESULTS

This review included seven randomized control trials. Four articles demonstrated a significant increase in SIRT-1 with different RSV dosages and interventions time. The secondary outcomes showed improvements in insulin sensitivity, lipid profile, metabolic flexibility, total antioxidant capacity, energy expenditure changes, and reduction of ectopic accumulation of fat.

CONCLUSION

Data from RCTs studies showed that RSV supplementation could stimulate SIRT-1 in humans, and therefore contribute to the treatment of excess weight and its comorbidities. However, more research is needed because it was not possible to confirm this effect truly. [PROSPERO registration number: CRD42020205571].

Polyphenols and their anti-obesity role mediated by the gut microbiota: a comprehensive review

Obesity is a global public health problem that results in chronic pathologies such as diabetes, cardiovascular diseases, and cancer. The treatment approach based on energy restriction and promotion of physical activity is ineffective in the long term. Due to the high prevalence of this pathology, complementary treatments such as brown adipose tissue activation (BAT) and white adipose tissue browning (WAT) have been proposed. Dietary polyphenols are plant secondary metabolites that can stimulate browning and thermogenesis of adipose tissue. They have also been shown to prevent body weight gain, and decrease systemic inflammation produced by high-fat diets. Ingested dietary polyphenols that reach the colon are metabolized by the gut microbiota (GM), regulating its composition and generating a great array of metabolites. GM is involved in the production of short chain fatty acids and secondary bile salts that regulate energetic metabolism. The alteration in the composition of GM observed in metabolic diseases such as obesity and type 2 diabetes can be attenuated by polyphenols. Recent studies support the hypothesis that GM would mediate WAT browning and BAT thermogenesis activation induced by polyphenol administration. Together, these results indicate that GM in the presence of polyphenols plays a fundamental role in the control of obesity possible through BAT activation.

Nutritional Regulation of Human Brown Adipose Tissue

The recent identification of brown adipose tissue in adult humans offers a new strategy to increase energy expenditure to treat obesity and associated metabolic disease. While white adipose tissue (WAT) is primarily for energy storage, brown adipose tissue (BAT) is a thermogenic organ that increases energy expenditure to generate heat. BAT is activated upon cold exposure and improves insulin sensitivity and lipid clearance, highlighting its beneficial role in metabolic health in humans. This review provides an overview of BAT physiology in conditions of overnutrition (obesity and associated metabolic disease), undernutrition and in conditions of altered fat distribution such as lipodystrophy. We review the impact of exercise, dietary macronutrients and bioactive compounds on BAT activity. Finally, we discuss the therapeutic potential of dietary manipulations or supplementation to increase energy expenditure and BAT thermogenesis. We conclude that chronic nutritional interventions may represent a useful nonpharmacological means to enhance BAT mass and activity to aid weight loss and/or improve metabolic health.

Sirtuins-Mediated System-Level Regulation of Mammalian Tissues at the Interface between Metabolism and Cell Cycle: A Systematic Review

Sirtuins are a family of highly conserved NAD+-dependent proteins and this dependency links Sirtuins directly to metabolism. Sirtuins' activity has been shown to extend the lifespan of several organisms and mainly through the post-translational modification of their many target proteins, with deacetylation being the most common modification. The seven mammalian Sirtuins, SIRT1 through SIRT7, have been implicated in regulating physiological responses to metabolism and stress by acting as nutrient sensors, linking environmental and nutrient signals to mammalian metabolic homeostasis. Furthermore, mammalian Sirtuins have been implicated in playing major roles in mammalian pathophysiological conditions such as inflammation, obesity and cancer. Mammalian Sirtuins are expressed heterogeneously among different organs and tissues, and the same holds true for their substrates. Thus, the function of mammalian Sirtuins together with their substrates is expected to vary among tissues. Any therapy depending on Sirtuins could therefore have different local as well as systemic effects. Here, an introduction to processes relevant for the actions of Sirtuins, such as metabolism and cell cycle, will be followed by reasoning on the system-level function of Sirtuins and their substrates in different mammalian tissues. Their involvement in the healthy metabolism and metabolic disorders will be reviewed and critically discussed.

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.

Metabolism and Metabolic Disorders and the Microbiome: The Intestinal Microbiota Associated With Obesity, Lipid Metabolism, and Metabolic Health-Pathophysiology and Therapeutic Strategies

Changes in the intestinal microbiome have been associated with obesity and type 2 diabetes, in epidemiological studies and studies of the effects of fecal transfer in germ-free mice. We review the mechanisms by which alterations in the intestinal microbiome contribute to development of metabolic diseases, and recent advances, such as the effects of the microbiome on lipid metabolism. Strategies have been developed to modify the intestinal microbiome and reverse metabolic alterations, which might be used as therapies. We discuss approaches that have shown effects in mouse models of obesity and metabolic disorders, and how these might be translated to humans to improve metabolic health.

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.

Lactococcus lactis and Resveratrol Decrease Body Weight and Increase Benefic Gastrointestinal Microbiota in Mice

BACKGROUND

The microbiome is now known for its important role in whole-body homeostasis. A dysbiosis of the normal microbiota is correlated with metabolic disorders. In this sense, the search for compounds able to modulate the microbiome is needed. Resveratrol, a natural compound found in grapes seems to be a promising candidate.

OBJECTIVE

In this study, our motivation was to evaluate the effects of the association between Resveratrol and Lactococcus lactis, a probiotic, on the composition of the gastrointestinal microbiota and body weight of mice.

METHODS

Twenty female mice were divided into 4 groups: (1) standard diet, (2) standard diet plus Lactococcus lactis, (3) standard diet plus resveratrol, and (4) standard diet plus Lactococcus lactis and resveratrol. At the end of the treatment period, samples of blood, mucus, stomach, and small and large intestines were collected for analysis. Total levels of Immunoglobulin A and Immunoglobulin E, Lac+ and Lac- bacteria and Lactobacillus were measured.

RESULTS

The main results indicate that the association between resveratrol and probiotics was able to decrease mice body weight, as compared to the other groups, in addition to decrease the number of Lac- bacteria and increasing the number of Lac+ bacteria. The levels of secretory IgA were also decreased, compared to the animals treated with only probiotics or resveratrol.

CONCLUSION

We observed potential synergism between Resveratrol and Lactococcus lactis mainly in modulating the stomach and intestinal microbiota.

Control of Adipose Cell Browning and Its Therapeutic Potential

Adipose tissue is the largest endocrine organ in humans and has an important influence on many physiological processes throughout life. An increasing number of studies have described the different phenotypic characteristics of fat cells in adults. Perhaps one of the most important properties of fat cells is their ability to adapt to different environmental and nutritional conditions. Hypothalamic neural circuits receive peripheral signals from temperature, physical activity or nutrients and stimulate the metabolism of white fat cells. During this process, changes in lipid inclusion occur, and the number of mitochondria increases, giving these cells functional properties similar to those of brown fat cells. Recently, beige fat cells have been studied for their potential role in the regulation of obesity and insulin resistance. In this context, it is important to understand the embryonic origin of beige adipocytes, the response of adipocyte to environmental changes or modifications within the body and their ability to transdifferentiate to elucidate the roles of these cells for their potential use in therapeutic strategies for obesity and metabolic diseases. In this review, we discuss the origins of the different fat cells and the possible therapeutic properties of beige fat cells.

Glyburide Regulates UCP1 Expression in Adipocytes Independent of KATP Channel Blockade

Identification of safe and effective compounds to increase or activate UCP1 expression in brown or white adipocytes remains a potent therapeutic strategy to combat obesity. Here we reported that, glyburide, one of the FDA-approved drugs currently used to treat type 2 diabetes, can significantly enhance UCP1 expression in both brown and white adipocytes. Glyburide-fed mice exhibited a clear resistance to high-fat diet-induced obesity, reduced blood triglyceride level, and increased UCP1 expression in brown adipose tissue. Moreover, in situ injection of glyburide to inguinal white adipose tissue remarkably enhanced UCP1 expression and increased thermogenesis. Further mechanistic studies indicated that the glyburide effect in UCP1 expression in adipocytes was KATP channel independent but may involve the regulation of the Ca2+-Calcineurin-NFAT signal pathway. Overall, our findings revealed the significant effects of glyburide in regulating UCP1 expression and thermogenesis in adipocytes, which can be potentially repurposed to treat obesity.

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.

Effects and mechanisms of edible and medicinal plants on obesity: an updated review

In recent years, obesity has become a global public health issue. It is closely associated with the occurrence of several chronic diseases, such as diabetes and cardiovascular diseases. Some edible and medicinal plants show anti-obesity activity, such as fruits, vegetables, spices, legumes, edible flowers, mushrooms, and medicinal plants. Numerous studies have indicated that these plants are potential candidates for the prevention and management of obesity. The major anti-obesity mechanisms of plants include suppressing appetite, reducing the absorption of lipids and carbohydrates, inhibiting adipogenesis and lipogenesis, regulating lipid metabolism, increasing energy expenditure, regulating gut microbiota, and improving obesity-related inflammation. In this review, the anti-obesity activity of edible and medicinal plants was summarized based on epidemiological, experimental, and clinical studies, with related mechanisms discussed, which provided the basis for the research and development of slimming products. Further studies should focus on the exploration of safer plants with anti-obesity activity and the identification of specific anti-obesity mechanisms.

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.

Maternal obesity modulates both the renin-angiotensin system in mice dams and fetal adiposity

Obesity is a chronic multifactorial disease and is currently a public health problem. Maternal obesity during pregnancy is more dangerous as it impairs the health of the mother and future generations. Obesity leads to several metabolic disorders. Since white adipose tissue is an endocrine tissue, obesity often leads to disordered secretion of inflammatory, glycemic, lipid and renin-angiotensin system (RAS) components. The RAS represents a link between obesity and its metabolic consequences. Therefore, our goal was to evaluate the possible changes caused by a high-fat diet in RAS-related receptor expression in the uterus and placenta of pregnant mice and determine the underlying effects of these changes in the fetuses' body composition. Breeding groups were formed after obesity induction by high-fat (HF) diet. Dams and fetuses were euthanized on the 19th day of the gestational period. The HF diet effectively induced obesity, glucose intolerance and insulin resistance in mice. Fetuses born from HF dams showed increased body weight and adiposity. Both results were accompanied by increased AT₁R expression in placenta and uterus together with increased angiotensin-converting enzyme expression in the uterus and a decreased expression of MAS1 in placenta of HF dams. These results suggest a link between RAS, maternal obesity induced by HF diet and the fetuses' body adiposity. This new path now can be more thoroughly explored.

Investigating Anti-Obesity Effects by Oral Administration of Aloe vera Gel Extract (AVGE): Possible Involvement in Activation of Brown Adipose Tissue (BAT)

The aim of this study is to investigate the mechanism of anti-obesity effects of Aloe vera gel extract (AVGE) containing Aloe sterols. Previously, we reported that oral intake of Aloe vera components has an anti-diabetic and anti-obesity effect. This study was designed to assess the role of brown adipose tissue (BAT) in the anti-obesity effect of AVGE. Six-week-old male mice were divided into three groups; STD (standard diet), HFD (60% high fat diet) and AVGE (60% high fat diet with AVGE treatment). During 11 wk of AVGE administration, body weight has been monitored. Tissue samples were obtained to be measured the weight and evaluated the gene expressions. Mice treated with AVGE had suppressed body weight, and liver and fat weight gain. To investigate BAT activation, we measured the expression of mRNA related to BAT thermogenesis. Mice in the AVGE group had higher expression of Ucp1, Adrb3, and Cidea in BAT compared to HFD. Next, to investigate the possibility that AVGE induced hepatic FGF21, which is an important factor for nutrient and energy homeostasis including BAT regulation, in vitro study was conducted. HepG2 cell stimulated by AVGE were highly expressed FGF21. These results suggested that BAT activation partially contributes to mechanism of anti-obesity effect of Aloe sterols in diet-induced obesity (DIO) models. However, further study is needed to determine the predominant mechanism.

Feeding brown fat: dietary phytochemicals targeting non-shivering thermogenesis to control body weight

Excessive adipose accumulation, which is the main driver for the development of secondary metabolic complications, has reached epidemic proportions and combined pharmaceutical, educational and nutritional approaches are required to reverse the current rise in global obesity prevalence rates. Brown adipose tissue (BAT) is a unique organ able to dissipate energy and thus a promising target to enhance BMR to counteract a positive energy balance. In addition, active BAT might support body weight maintenance after weight loss to prevent/reduce relapse. Natural products deliver valuable bioactive compounds that have historically helped to alleviate disease symptoms. Interest in recent years has focused on identifying nutritional constituents that are able to induce BAT activity and thereby enhance energy expenditure. This review provides a summary of selected dietary phytochemicals, including isoflavones, catechins, stilbenes, the flavonoids quercetin, luteolin and resveratrol as well as the alkaloids berberine and capsaicin. Most of the discussed phytochemicals act through distinct molecular pathways e.g. sympathetic nerve activation, AMP-kinase signalling, SIRT1 activity or stimulation of oestrogen receptors. Thus, it might be possible to utilise this multitude of pathways to co-activate BAT using a fine-tuned combination of foods or combined nutritional supplements.

Resveratrol inhibits adipocyte differentiation and cellular senescence of human bone marrow stromal stem cells

Bone marrow adipose tissue (BMAT) is a unique adipose depot originating from bone marrow stromal stem cells (BMSCs) and regulates bone homeostasis and energy metabolism. An increased BMAT volume is observed in several conditions e.g. obesity, type 2 diabetes, osteoporosis and is known to be associated with bone fragility and increased risk for fracture. Therapeutic approaches to decrease the accumulation of BMAT are clinically relevant. In a screening experiment of natural compounds, we identified Resveratrol (RSV), a plant-derived antioxidant mediating biological effects via sirtuin- related mechanisms, to exert significant effects of BMAT formation. Thus, we examined in details the effects RSV on adipocytic and osteoblastic differentiation of tolermerized human BMSCs (hBMSC-TERT). RSV (1.0 μM) enhanced osteoblastic differentiation and inhibited adipocytic differentiation of hBMSC-TERT when compared with control and Sirtinol (Sirtuin inhibitor). Global gene expression profiling and western blot analysis revealed activation of a number of signaling pathways including focal adhesion kinase (FAK). Pharmacological inhibition of FAK using (PF-573228) and AKT inhibitor (LY-294002) (5μM), diminished RSV-induced osteoblast differentiation. In addition, RSV reduced the levels of senescence-associated secretory phenotype (SASP), gene markers associated with senescence (P53, P16, and P21), intracellular ROS levels and increased gene expression of enzymes protecting cells from oxidative damage (HMOX1 and SOD3). In vitro treatment of primary hBMSCs from aged patients characterized with high adipocytic and low osteoblastic differentiation ability with RSV, significantly enhanced osteoblast and decreased adipocyte formation when compared to hBMSCs from young donors. RSV targets hBMSCs and inhibits adipogenic differentiation and senescence-associated phenotype and thus a potential agent for treating conditions of increased BMAT formation.

Resveratrol enhances brown adipose tissue activity and white adipose tissue browning in part by regulating bile acid metabolism via gut microbiota remodeling

OBJECTIVE

Current evidence has linked dietary resveratrol (RSV) intake to the activation of brown adipose tissue (BAT) and induction of white adipose tissue (WAT) browning, which may be a potential means of improving glucose homeostasis. However, the underlying mechanisms remain unclear.

METHODS

A diet containing RSV was fed to db/db mice for 10 weeks, following which the body weight, adipose tissue accumulation, bile acid (BA) profiles, and markers of BA metabolism were analyzed. Oral glucose tolerance testing, immunohistochemistry, and gut microbiota sequencing were also performed.

RESULTS

RSV intervention improved glucose homeostasis in db/db mice, which was linked to the enhanced BAT activity and WAT browning. Moreover, RSV-treated mice exhibited altered plasma and fecal BA compositions and significant remodeling of the gut microbiota, the latter confirmed by a higher level of lithocholic acid (LCA) in the plasma and feces. LCA was identified to be the agonist of Takeda G-protein coupled receptor 5 (TGR5), which mediated the BAT activation and WAT browning by upregulating uncoupling protein 1 (UCP1) expression. Furthermore, depletion of the gut microbiota using antibiotics partially abolished the beneficial effects of RSV against glucose intolerance. Finally, microbiota transplantation experiments demonstrated that the RSV-induced beneficial effects were transferable, indicating that these effects were largely dependent on the gut microbiota.

CONCLUSIONS

These data indicate that RSV administration improves glucose homeostasis by enhancing BAT activation and WAT browning, a mechanism that might partially be mediated by the gut microbiota-BA-TGR5/UCP1 pathway.

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.

Withania somnifera Extract Enhances Energy Expenditure via Improving Mitochondrial Function in Adipose Tissue and Skeletal Muscle

Withania somnifera (WS), commonly known as ashwagandha, possesses diverse biological functions. WS root has mainly been used as an herbal medicine to treat anxiety and was recently reported to have an anti-obesity effect, however, the mechanisms underlying its action remain to be explored. We hypothesized that WS exerts its anti-obesity effect by enhancing energy expenditure through improving the mitochondrial function of brown/beige adipocytes and skeletal muscle. Male C57BL/6J mice were fed a high-fat diet (HFD) containing 0.25% or 0.5% WS 70% ethanol extract (WSE) for 10 weeks. WSE (0.5%) supplementation significantly suppressed the increases in body weight and serum lipids, and lipid accumulation in the liver and adipose tissue induced by HFD. WSE supplementation increased oxygen consumption and enhanced mitochondrial activity in brown fat and skeletal muscle in the HFD-fed mice. In addition, it promoted browning of subcutaneous fat by increasing mitochondrial uncoupling protein 1 (UCP1) expression. Withaferin A (WFA), a major compound of WS, enhanced the differentiation of pre-adipocytes into beige adipocytes and oxygen consumption in C2C12 murine myoblasts. These results suggest that WSE ameliorates diet-induced obesity by enhancing energy expenditure via promoting mitochondrial function in adipose tissue and skeletal muscle, and WFA is a key regulator in this function.

Resveratrol promotes white adipocytes browning and improves metabolic disorders in Sirt1-dependent manner in mice

Obesity has become an epidemic concern in modern society. The chronic obesity is associated with metabolic disorders, such as hyperglycemia, hyperlipidemia, fatty liver, and cadiovascular disease, which cause high risk for mortality. The novel potential strategy to overcome obesity is to "burn out" the extra fat via "browning" of the white adipose tissues. The phytochemical resveratrol (Res) has attracted substantial attention due to its powerful amelioratory effects in metabolic diseases. However, how Res regulates the browning of adipose tissues remains largely elusive. Our data show that the NAD⁺ -dependent deacetylase silent information regulator 1 (Sirt1) mediates Res-induced browning and fat reduction of adipocytes, as well as other Res-improved metabolic phenotypes including hyperglycemina and hyperlipidemia in mice. Interestingly, we found that the major metabolites of Res in vivo (Res-3-O-glucuronide, Res-4'-O-glucuronide, and Res-3-O-sulfate) were much less potent in promoting browning gene expressions and reducing fat content in comparison to Res itself in mouse and human adipocytes in vitro, suggesting the importance and necessarity to enhance the bioavailability of Res in vivo in consideration of therapeutic application. Taken together, our findings clarify the beneficial effects of Res on excess fat utilization via promotion of browning in a Sirt1-dependent manner, suggesting the potential therapeutic application of Res in the treatment of obesity and related metabolic disorders.

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.

The influence of dietary conditions in the effects of resveratrol on hepatic steatosis

Non-alcoholic fatty liver disease (NAFLD) is considered the major cause for the development of chronic liver alterations.