Effects and mechanisms of resveratrol on the amelioration of oxidative stress and hepatic steatosis in KKAy mice

Forkhead box O1 in metabolic dysfunction-associated fatty liver disease: molecular mechanisms and drug research

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a chronic liver disease that progresses from hepatic steatosis to non-alcoholic steatohepatitis, cirrhosis, and liver cancer, posing a huge burden on human health. Existing research has confirmed that forkhead box O1 (FOXO1), as a member of the FOXO transcription factor family, is upregulated in MAFLD. Its activity is closely related to nuclear-cytoplasmic shuttling and various post-translational modifications including phosphorylation, acetylation, and methylation. FOXO1 mediates the progression of MAFLD by regulating glucose metabolism, lipid metabolism, insulin resistance, oxidative stress, hepatic fibrosis, hepatocyte autophagy, apoptosis, and immune inflammation. This article elaborates on the regulatory role of FOXO1 in MAFLD, providing a summary and new insights for the current status of drug research and targeted therapies for MAFLD.

Overexpression of GPX2 gene regulates the development of porcine preadipocytes and skeletal muscle cells through MAPK signaling pathway

Glutathione peroxidase 2 (GPX2) is a selenium-dependent enzyme and protects cells against oxidative damage. Recently, GPX2 has been identified as a candidate gene for backfat and feed efficiency in pigs. However, it is unclear whether GPX2 regulates the development of porcine preadipocytes and skeletal muscle cells. In this study, adenoviral gene transfer was used to overexpress GPX2. Our findings suggest that overexpression of GPX2 gene inhibited proliferation of porcine preadipocytes. And the process is accompanied by the reduction of the p-p38. GPX2 inhibited adipogenic differentiation and promoted lipid degradation, while ERK1/2 was reduced and p-p38 was increased. Proliferation of porcine skeletal muscle cells was induced after GPX2 overexpression, was accompanied by activation in JNK, ERK1/2, and p-p38. Overexpression methods confirmed that GPX2 has a promoting function in myoblastic differentiation. ERK1/2 pathway was activated and p38 was suppressed during the process. This study lays a foundation for the functional study of GPX2 and provides theoretical support for promoting subcutaneous fat reduction and muscle growth.

SIRT1: Harnessing multiple pathways to hinder NAFLD

Non-alcoholic fatty liver disease (NAFLD) encompasses hepatic steatosis, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. It is the primary cause of chronic liver disorders, with a high prevalence but no approved treatment. Therefore, it is indispensable to find a trustworthy therapy for NAFLD. Recently, mounting evidence illustrates that Sirtuin 1 (SIRT1) is strongly associated with NAFLD. SIRT1 activation or overexpression attenuate NAFLD, while SIRT1 deficiency aggravates NAFLD. Besides, an array of therapeutic agents, including natural compounds, synthetic compounds, traditional Chinese medicine formula, and stem cell transplantation, alleviates NALFD via SIRT1 activation or upregulation. Mechanically, SIRT1 alleviates NAFLD by reestablishing autophagy, enhancing mitochondrial function, suppressing oxidative stress, and coordinating lipid metabolism, as well as reducing hepatocyte apoptosis and inflammation. In this review, we introduced the structure and function of SIRT1 briefly, and summarized the effect of SIRT1 on NAFLD and its mechanism, along with the application of SIRT1 agonists in treating NAFLD.

Calorie restriction mimetic, resveratrol, attenuates hepatic ischemia and reperfusion injury through enhancing efferocytosis of macrophages via AMPK/STAT3/S1PR1 pathway

Calorie restriction (CR) mimetic, resveratrol (RSV), has the capacity of promoting phagocytosis. However, its role in hepatic ischemia and reperfusion injury (HIRI) remains poorly understood. This study aimed to investigate the effect of RSV on alleviating HIRI and explore the underlying mechanisms. RSV was intraperitoneally injected in mice HIRI model, while RSV was co-incubated with culture medium for 24 h in RAW 264.7 cells and kupffer cells. Macrophage efferocytosis was assessed by immunostaining of PI and F4/80. The clearance of apoptotic neutrophils in the liver was determined by immunostaining of Ly6-G and cleaved-caspase-3. HE staining, Suzuki's score, serum levels of ALT, AST, TNF-α and IL-1β were analyzed to evaluate HIRI. The efferocytosis inhibitor, Cytochalasin D, was utilized to investigate the effect of RSV on HIRI. Western blot was employed to measure the levels of AMPKα, phospho-AMPKα, STAT3, phospho-STAT3 and S1PR1. SiSTAT3 and inhibitors targeting AMPK, STAT3 and S1PR1, respectively, were used to confirm the involvement of AMPK/STAT3/S1PR1 pathway in RSV-mediated efferocytosis and HIRI. RSV facilitated the clearance of apoptotic neutrophils and attenuated HIRI, which was impeded by Cytochalasin D. RSV boosted macrophage efferocytosis by up-regulating the levels of phospho-AMPKα, phospho-STAT3 and S1PR1, which was reversed by AMPK, STAT3 and S1PR1 inhibitors, respectively. Inhibition of STAT3 suppressed RSV-induced clearance of apoptotic neutrophils and exacerbated HIRI. CR mimetic, RSV, alleviates HIRI by promoting macrophages efferocytosis through AMPK/STAT3/S1PR1 pathway, providing valuable insights into the mechanisms underlying the protective effects of CR on attenuating HIRI.

Anti-Hyperglycemic Effect of the Brown Slime Cap Mushroom Chroogomphus rutilus (Agaricomycetes) Crude Polysaccharide In Vitro and In Vivo

The prevalence of diabetes is increasing worldwide, and it is very important to study new hypoglycemic active substances. In this study, we investigated the hypoglycemic effect of Chroogomphus rutilus crude polysaccharide (CRCP) in HepG2 cells and streptozotocin-induced diabetic mice. A glucose consumption experiment conducted in HepG2 cells demonstrated the in vitro hypoglycemic activity of CRCP. Furthermore, CRCP exhibited significant hypoglycemic effects and effectively ameliorated insulin resistance in insulin resistant HepG2 cells. In high-fat diet and streptozotocin-induced diabetic mice, after 4 weeks of CRCP administration, fasting blood glucose, fasting serum insulin, triglyceride, total cholesterol, low-density lipoprotein cholesterol, glutamate transaminase, alanine transaminase, and insulin resistance index significantly decreased, while high-density lipoprotein cholesterol and insulin sensitivity index (ISI) were markedly increased. Moreover, hematoxylin-eosin (HE) staining and immunofluorescence labeling of tissue sections indicated that CRCP attenuated the pathological damage of liver and pancreas in diabetic mice. These results indicate that CRCP is a potential hypoglycemic agent.

Kaempferol attenuates nonalcoholic fatty liver disease in type 2 diabetic mice via the Sirt1/AMPK signaling pathway

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases with limited treatment options. Moreover, its prevalence is doubled in type 2 diabetes mellitus (T2DM). Kaempferol (KAP) is a flavonoid compound that has been suggested to have beneficial effects on NAFLD, but studies on the mechanism are lacking, especially in the diabetic state. Herein, we investigated the effect of KAP on NAFLD associated with T2DM and its underlying mechanism in vitro and in vivo. The results of in vitro studies indicated that KAP treatment (10-8-10-6 M) significantly reduced lipid accumulation in oleic acid-induced HepG2 cells. Moreover, in the T2DM animal model of db/db mice, we confirmed that KAP (50 mg/kg) significantly reduced lipid accumulation and improved liver injury. Mechanistic studies in vitro and in vivo showed that Sirtuin 1 (Sirt1)/AMP-activated protein kinase (AMPK) signal was involved in KAP regulation of hepatic lipid accumulation. KAP treatment activated Sirt1 and AMPK, upregulated the levels of fatty acid oxidation-related protein proliferator activated receptor gamma coactivator 1α (PGC1α); and downregulated lipid synthesis-related proteins, including acetyl-coA carboxylase (ACC), fatty acid synthase (FASN), and sterol regulatory element-binding protein 1 (SREBP1). Furthermore, the curative effect of KAP on lipid accumulation was abolished by siRNA-mediated knockdown of either Sirt1 or AMPK. Collectively, these findings suggest that KAP may be a potential therapeutic agent for NAFLD associated with T2DM by regulating hepatic lipid accumulation through activation of Sirt1/AMPK signaling.

The role of resveratrol in diabetes and obesity associated with insulin resistance

Diabetes mellitus is a significant health problem that is caused by chronic hyperglycaemia as a result of inadequate insulin production or ineffective insulin action in the body. In recent years, many new pharmacological and non-pharmacological therapies have been developed for improving pancreatic insulin secretion and insulin resistance. Resveratrol is a natural and biologically active stilbenoid polyphenol present in various plant species and has the potential to benefit diabetes. The anti-diabetic actions of resveratrol have also been extensively studied in diabetic human and animal models. Moreover, resveratrol might affect insulin sensitivity by regulating visceral fat derivated adipokine levels. The use of resveratrol in combination with anti-diabetic therapies or alone may have significant potential for the management of diabetes mellitus. This review provides an overview of the anti-diabetic action of resveratrol as well as the possible mechanisms that have an effect on insulin secretion and insulin resistance in diabetics.

Polyphenols as potential metabolism mechanisms regulators in liver protection and liver cancer prevention

BACKGROUND

Liver cancer is one of the common malignancies. The dysregulation of metabolism is a driver of accelerated tumourigenesis. Metabolic changes are well documented to maintain tumour growth, proliferation and survival. Recently, a variety of polyphenols have been shown to have a crucial role both in liver disease prevention and metabolism regulation.

METHODS

We conducted a literature search and combined recent data with systematic analysis to comprehensively describe the molecular mechanisms that link polyphenols to metabolic regulation and their contribution in liver protection and liver cancer prevention.

RESULTS

Targeting metabolic dysregulation in organisms prevents and resists the development of liver cancer, which has important implications for identifying new therapeutic strategies for the management and treatment of cancer. Polyphenols are a class of complex compounds composed of multiple phenolic hydroxyl groups and are the main active ingredients of many natural plants. They mediate a broad spectrum of biological and pharmacological functions containing complex lipid metabolism, glucose metabolism, iron metabolism, intestinal flora imbalance, as well as the direct interaction of their metabolites with key cell-signalling proteins. A large number of studies have found that polyphenols affect the metabolism of organisms by interfering with a variety of intracellular signals, thereby protecting the liver and reducing the risk of liver cancer.

CONCLUSION

This review systematically illustrates that various polyphenols, including resveratrol, chlorogenic acid, caffeic acid, dihydromyricetin, quercetin, catechins, curcumin, etc., improve metabolic disorders through direct or indirect pathways to protect the liver and fight liver cancer.

GPX2 Gene Affects Feed Efficiency of Pigs by Inhibiting Fat Deposition and Promoting Muscle Development

GPX2 has been recognized as a potential candidate gene for feed efficiency in pigs. This article aimed to elucidate polymorphism of GPX2 associated with feed efficiency and its related molecular mechanism. In this study, seven single nucleotide polymorphisms (SNP) of GPX2 were found among 383 Duroc pigs. In addition, seven SNPs and ALGA0043483 (PorcineSNP60 BeadChip data in 600 Duroc pigs), which are near the GPX2 gene, were identified in one haplotypes block. Furthermore, associated studies showed that the genotype of GPX2 has significant association with weaning weight and 100 kg BF in Duroc pigs. In addition, the AG had no effect when the backfat became thinner, and the FCR and RFI traits had a tendency to decrease in the G3 + TT combination genotype, accompanied by an increase of GPX2 expression in backfat and muscle tissues. At the cellular level, the adipocyte proliferation and ability of adipogenic differentiation were reduced, and the lipid degradation increased in 3T3-L1 when there was overexpression of GPX2. In contrast, overexpression of the GPX2 gene can promote the muscle cell proliferation and myogenic differentiation in C2C12 cells. In other words, GPX2 has the effect of reducing fat deposition and promoting muscle development, and it is a candidate gene for backfat and feed efficiency.

Progress in the Preclinical and Clinical Study of Resveratrol for Vascular Metabolic Disease

Vascular metabolic dysfunction presents in various diseases, such as atherosclerosis, hypertension, and diabetes mellitus. Due to the high prevalence of these diseases, it is important to explore treatment strategies to protect vascular function. Resveratrol (RSV), a natural polyphenolic phytochemical, is regarded as an agent to regulate metabolic pathways. Many studies have proven that RSV has beneficial effects on improving metabolism in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), which provide new directions to treat vascular metabolic diseases. Herein, we overviewed that RSV could regulate cell metabolism activity by inhibiting glucose uptake, suppressing glycolysis, preventing cells from fatty acid-related damages, reducing lipogenesis, increasing fatty acid oxidation, enhancing lipolysis, elevating uptake and synthesis of glutamine, and increasing NO release. Furthermore, in clinical trials, although the results from different studies remain controversial, we proposed that RSV had better therapeutic effects at high concentrations and for patients with metabolic disorders.

Combined resveratrol and vitamin D treatment ameliorate inflammation-related liver fibrosis, ER stress, and apoptosis in a high-fructose diet/streptozotocin-induced T2DM model

A high fructose diet is a major cause of diabetes and various metabolic disorders, including fatty liver. In this study, we investigated the effects of resveratrol and vitamin D (VitD) treatments on endoplasmic reticulum (ER) stress, oxidative stress, inflammation, apoptosis, and liver regeneration in a rat model of type 2 diabetes mellitus, namely, T2DM Sprague-Dawley rats. This T2DM rat model was created through a combination treatment of a 10% fructose diet and 40 mg/kg streptozotocin (STZ). Resveratrol (1 mg/kg/day) and VitD (170/IU/week) were administered alone and in combination to both the diabetic and control groups. Immunohistochemical staining was performed to evaluate PCNA, NF-κB, TNF-α, IL-6, IL-1β, GRP78, and active caspase-3 in liver tissue. The TUNEL method and Sirius red staining were used to determine apoptosis and fibrosis, respectively. G6PD, 6-PGD, GR, and GST activities were measured to determine oxidative stress status. We found that the expressions of cytokines (TNF-α, IL-6, and IL-1β) correlated with NF-κB activation and were significantly increased in the T2DM rats. Increased GRP78 expression, indicating ER stress, increased in apoptotic cells, enhanced caspase-3 activation, and collagen accumulation surrounding the central vein were observed in the T2DM group compared with the other groups. The combination VitD + resveratrol treatment improved antioxidant defense via increasing G6PD, 6-PGD, GR, and GST activities compared to the diabetic groups. We concluded that the combined administration of resveratrol with VitD ameliorates the adverse effects of T2DM by regulating blood glucose levels, increasing antioxidant defense mechanisms, controlling ER stress, enhancing tissue regeneration, improving inflammation, and reducing apoptosis in liver cells. In conclusion, this study indicates that the combination treatment of resveratrol + VitD can be a beneficial option for preventing liver damage in fructose-induced T2DM.

Phytochemicals targeting NAFLD through modulating the dual function of forkhead box O1 (FOXO1) transcription factor signaling pathways

Literature evidence reveals that natural compounds are potential candidates for ameliorating obesity-associated non-alcoholic fatty liver disease (NAFLD) by targeting forkhead box O1 (FOXO1) transcription factor. FOXO1 has a dual and complex role in regulating both increase and decrease in lipid accumulation in hepatocytes and adipose tissues (AT) at different stages of NAFLD. In insulin resistance (IR), it is constitutively expressed, resulting in increased hepatic glucose output and lipid metabolism irregularity. The studies on different phytochemicals indicate that dysregulation of FOXO1 causes disturbance in cellular nutrients homeostasis, and the natural entities have an enduring impact on the mitigation of these abnormalities. The current review communicates and evaluates certain phytochemicals through different search engines, targeting FOXO1 and its downstream cellular pathways to find lead compounds as potential therapeutic agents for treating NAFLD and related metabolic disorders. The findings of this review confirm that polyphenols, flavonoids, alkaloids, terpenoids, and anthocyanins are capable of modulating FOXO1 and associated signaling pathways, and they are potential therapeutic agents for NAFLD and related complications. HIGHLIGHTS: • FOXO1 has the potential to be targeted by novel drugs from natural sources for the treatment of NAFLD and obesity. • FOXO1 regulates cellular autophagy, inflammation, oxidative stress, and lipogenesis through alternative mechanisms. • Phytochemicals treat NAFLD by acting on FOXO1 or SREBP1c and PPARγ transcription factor signaling pathways.

Protective Effects of Resveratrol and Apigenin Dietary Supplementation on Serum Antioxidative Parameters and mRNAs Expression in the Small Intestines of Diquat-Challenged Pullets

Poultry as a large-scale intensive farming is vulnerable to oxidative stress. Resveratrol and apigenin are recognized to have many beneficial bioactive functions. This study tested the hypothesis that dietary resveratrol and apigenin supplementation alleviates oxidative stress in the small intestine of diquat-challenged pullets. A total of 200 healthy pullets were randomly divided into four treatment groups: control group fed with a basal diet (CON), diquat group fed with a basal diet (DIQ), resveratrol group fed with a basal diet containing 500 mg/kg resveratrol (RES), and an apigenin group fed with a basal diet containing 500 mg/kg apigenin (API) and injected intraperitoneally with either 1 ml of saline (CON) or 8 mg/kg body weight of diquat (DIQ, RES, and API) to induce oxidative stress. The day of the injection was considered as day 0. The results indicated that resveratrol and apigenin were able to decrease the malondialdehyde (MDA) level and upregulate total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) levels in serum on day 1 and 10 after being diquat-challenged. In addition, resveratrol increased mRNA expression of NQO1 (NAD(P)H dehydrogenase quinone 1) and HO-1 (heme oxygenase-1) in ileum and jejunum on day 10, while apigenin upregulated nuclear factor erythroid 2-related factor 2 (NRF2), NQO1, and HO-1 in ileum and jejunum on day 10. Both resveratrol and apigenin increased the mRNA expression of CLAUDIN-1 in ileum and jejunum on day 1 and that of ZO-1 (zonula occludens-1) in ileum on day 10 post-diquat-injection. These findings indicate that dietary supplementation with resveratrol and apigenin attenuates oxidative stress involving NRF2 signaling pathways in diquat-challenged pullets to some extent. These observations are valuable for the chicken industry and resveratrol and apigenin applications in animal husbandry.

Saikokeishikankyoto extract alleviates muscle atrophy in KKAy mice

Sarcopenic obesity is associated with increased visceral fat and decreased muscle mass, resulting in decreased insulin sensitivity, increased production of inflammatory cytokines, and oxidative stress. In this study, we first evaluated the effects of herbal medicines on the transcriptional activity of the Sirtuin 1 (sirt1) promoter in vitro as an indicator of their therapeutic effect. Our data suggested that hot water Saikokeishikankyoto (SKK) extracts increased sirt1 transcriptional activity in vitro, identifying it as a candidate therapeutic for evaluation in the KKAy type 2 diabetic obesity mouse model. These in vivo evaluations revealed that SKK treatment increased the wet weight and muscle fiber content in cross sections of the gastrocnemius muscle (GA) and restored motor function in these animals. In addition, SKK treatment reduced tumor necrosis factor-α (TNFα) expression in the sera and suppressed Atrogin1 and MuRF1 transcription in the GA samples. This treatment also increased sirt1 expression in these tissues. These results suggest that SKK inhibits skeletal muscle atrophy and improves motor function in KKAy mice by suppressing inflammation. In actual clinical practice, SKK is expected to inhibit muscle atrophy and improve motor dysfunction in sarcopenic obesity.

Therapeutic Effects of Resveratrol on Nonalcoholic Fatty Liver Disease Through Inflammatory, Oxidative Stress, Metabolic, and Epigenetic Modifications

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing around the world, in association with the progressive elevation in overweight and obesity. The accumulation of lipids in NAFLD patients contributes to the development of insulin resistance, inflammation and oxidative stress in hepatocytes, and alteration of blood lipids and glycaemia. There are currently no effective pharmacological therapies for NAFLD, although lifestyle and dietary modifications targeting weight reduction are among the prevailing alternative approaches. For this reason, new approaches should be investigated. The natural polyphenol resveratrol represents a potential new treatment for management of NAFLD due to anti-inflammatory and antioxidant properties. Although preclinical trials have demonstrated promising results of resveratrol against NALFD, the lack of conclusive results creates the need for more trials with larger numbers of patients, longer time courses, and standardized protocols.

Hepatoprotective and therapeutic effects of resveratrol: A focus on anti-inflammatory and anti- oxidative activities

Being the most essential organ in the body, the liver performs critical functions. Hepatic disorders, such as alcoholic liver disease, hepatic steatosis, liver fibrosis, non-alcoholic fatty liver disease, hepatocellular carcinoma and hepatic failure, have an impact on the biochemical and physiological functions of the body. The main representative of the flavonoid subgroup of flavones, Resveratrol (RES), exhibits suitable pharmacological activities for treating various liver diseases, such as fatty hepatitis, liver steatosis, liver cancer and liver fibrosis. According to various studies, grapes and red wine are good sources of RES. RES has various health properties; it is anti-inflammatory, anti-apoptotic, anti-oxidative and hepatoprotective against several hepatic diseases and hepatoxicity. Therefore, we performed a thorough research and created a summary of the distinct targets of RES in various stages of liver diseases. We concluded that RES inhibited liver inflammation essentially by causing a significant decrease in the expression of various pro-inflammatory cytokines like TNF-α, IL-1α, IL-1β, and IL-6. It also inhibits the transcription factor nuclear NF-κB that brings about the inflammatory cascade. RES also inhibits the PI3K/Akt/mTOR pathway to induce apoptosis. Additionally, it reduces oxidative stress in hepatic tissue by markedly reducing MDA and NO contents, and significantly increasing the levels of CAT, SOD and reduced GSH, in addition to AST and ALT, against toxic chemicals like CC14, As2O3 and TTA. Due to its anti-oxidant, anti-inflammatory and anti-fibrotic properties, RES reduces liver injury markers. RES is safe natural antioxidant that provides pharmacological rectification of the hepatoxicity of toxic chemicals.

Foresight regarding drug candidates acting on the succinate-GPR91 signalling pathway for non-alcoholic steatohepatitis (NASH) treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, and it is a liver manifestation of metabolic syndrome, with a histological spectrum from simple steatosis to non-alcoholic steatohepatitis (NASH). NASH can evolve into progressive liver fibrosis and eventually lead to liver cirrhosis. The pathological mechanism of NASH is multifactorial, involving a series of metabolic disorders and changes that trigger low-level inflammation in the liver and other organs. In the pathogenesis of NASH, the signal transduction pathway involving succinate and the succinate receptor (G-protein-coupled receptor 91, GPR91) regulates inflammatory cell activation and liver fibrosis. This review describes the mechanism of the succinate-GPR91 signalling pathway in NASH and summarizes the drugs that act on this pathway, with the aim of providing a new approach to NASH treatment.

Silent Information Regulator T1 in Aqueous Humor of Patients with Age-Related Macular Degeneration

Purpose:

The purpose of this study is to compare the aqueous humor level of Silent Information Regulator T1 (SIRT1) between patients with Age-related Macular Degeneration (AMD) and cataract patients.

Materials and Methods:

Aqueous humor level of SIRT1 was measured by enzyme-linked immunosorbent assay in 13 patients with wet-type AMD (n=13, AMD group) and 13 patients with cataracts (cataract group). In addition, the thickness of each retinal layer was determined by optical coherence tomography.

Results:

The aqueous humor level of SIRT1 was significantly lower in the AMD group than in the cataract group (p=0.007). In the AMD group, the SIRT1 level was positively correlated with the thickness of the retinal ganglion cell layer (r=0.31) and the inner nuclear layer (r=0.76).

Conclusion:

The aqueous level of SIRT1 decreased as the ganglion cell layer and inner nuclear layer became thinner, suggesting that reduction of SIRT1 activity might be involved in the pathogenesis of this disease.

The Effect of Resveratrol on the Cardiovascular System from Molecular Mechanisms to Clinical Results

Cardiovascular diseases are the leading causes of death worldwide. The cardioprotective effects of natural polyphenols such as resveratrol (3,5,4-trihydroxystilbene) have been extensively investigated throughout recent decades. Many studies of RES have focused on its favorable effects on pathological conditions related to cardiovascular diseases and their risk factors. The aim of this review was to summarize the wide beneficial effects of resveratrol on the cardiovascular system, including signal transduction pathways of cell longevity, energy metabolism of cardiomyocytes or cardiac remodeling, and its anti-inflammatory and antioxidant properties. In addition, this paper discusses the significant preclinical and human clinical trials of recent years with resveratrol on cardiovascular system. Finally, we present a short overview of antiviral and anti-inflammatory properties and possible future perspectives on RES against COVID-19 in cardiovascular diseases.

Beneficial Effects of Resveratrol in Mouse Gastrocnemius: A Hint to Muscle Phenotype and Proteolysis

We hypothesized that the phenolic compound resveratrol mitigates muscle protein degradation and loss and improves muscle fiber cross-sectional area (CSA) in gastrocnemius of mice exposed to unloading (7dI). In gastrocnemius of mice (female C57BL/6J, 10 weeks) exposed to a seven-day period of hindlimb immobilization with/without resveratrol treatment, markers of muscle proteolysis (tyrosine release, systemic troponin-I), atrophy signaling pathways, and muscle phenotypic features and function were analyzed. In gastrocnemius of unloaded mice treated with resveratrol, body and muscle weight and function were attenuated, whereas muscle proteolysis (tyrosine release), proteolytic and apoptotic markers, atrophy signaling pathways, and myofiber CSA significantly improved. Resveratrol treatment of mice exposed to a seven-day period of unloading prevented body and muscle weight and limb strength loss, while an improvement in muscle proteolysis, proteolytic markers, atrophy signaling pathways, apoptosis, and muscle fiber CSA was observed in the gastrocnemius muscle. These findings may have potential therapeutic implications in the management of disuse muscle atrophy in clinical settings.

The transcription factors CREBH, PPARa, and FOXO1 as critical hepatic mediators of diet-induced metabolic dysregulation

The liver is a critical mediator of lipid and/or glucose homeostasis and is a primary organ involved in dynamic changes during feeding and fasting. Additionally, hepatic-centric pathways are prone to dysregulation during pathophysiological states including metabolic syndrome (MetS) and non-alcoholic fatty liver disease. Omics platforms and GWAS have elucidated genes related to increased risk of developing MetS and related disorders, but mutations in these metabolism-related genes are rare and cannot fully explain the increasing prevalence of MetS-related pathologies worldwide. Complex interactions between diet, lifestyle, environmental factors, and genetic predisposition jointly determine inter-individual variability of disease risk. Given the complexity of these interactions, researchers have focused on master regulators of metabolic responses incorporating and mediating the impact of multiple environmental cues. Transcription factors are DNA binding, terminal executors of signaling pathways that modulate the cellular responses to complex metabolic stimuli and are related to the control of hepatic lipid and glucose homeostasis. Among numerous hepatic transcription factors involved in regulating metabolism, three emerge as key players in transducing nutrient sensing, which are dysregulated in MetS-related perturbations in both clinical and preclinical studies: cAMP Responsive Element Binding Protein 3 Like 3 (CREB3L3), Peroxisome Proliferator Activated Receptor Alpha (PPAR), and Forkhead Box O1 (FOXO1). Additionally, these three transcription factors appear to be amenable to dietary and/or nutrient-based therapies, being potential targets of nutritional therapy. In this review we aim to describe the activation, regulation, and impact of these transcription factors in the context of metabolic homeostasis. We also summarize their perspectives in MetS and nutritional therapies.

Curcumin and Resveratrol Improve Muscle Function and Structure through Attenuation of Proteolytic Markers in Experimental Cancer-Induced Cachexia

Muscle wasting and cachexia are prominent comorbidities in cancer. Treatment with polyphenolic compounds may partly revert muscle wasting. We hypothesized that treatment with curcumin or resveratrol in cancer cachectic mice may improve muscle phenotype and total body weight through attenuation of several proteolytic and signaling mechanisms in limb muscles. In gastrocnemius and soleus muscles of cancer cachectic mice (LP07 adenocarcinoma cells, N = 10/group): (1) LC-induced cachexia, (2) LC-cachexia+curcumin, and (3) LC-cachexia + resveratrol, muscle structure and damage (including blood troponin I), sirtuin-1, proteolytic markers, and signaling pathways (NF-κB and FoxO3) were explored (immunohistochemistry and immunoblotting). Compared to nontreated cachectic mice, in LC-cachexia + curcumin and LC-cachexia + resveratrol groups, body and muscle weights (gastrocnemius), limb muscle strength, muscle damage, and myofiber cross-sectional area improved, and in both muscles, sirtuin-1 increased, while proteolysis (troponin I), proteolytic markers, and signaling pathways were attenuated. Curcumin and resveratrol elicited beneficial effects on fast- and slow-twitch limb muscle phenotypes in cachectic mice through sirtuin-1 activation, attenuation of atrophy signaling pathways, and proteolysis in cancer cachectic mice. These findings have future therapeutic implications as these natural compounds, separately or in combination, may be used in clinical settings of muscle mass loss and dysfunction including cancer cachexia.

Phloroglucinol prevents albumin glycation as well as diminishes ROS production, glycooxidative damage, nitrosative stress and inflammation in hepatocytes treated with high glucose

The treatment of diabetes mellitus aftermaths became one of medicine's most significant therapeutical and financial issues in the XXI century. Most of which are related to protein glycation and oxidative stress caused by long lasting periods of hyperglycemia. Thus, even within a venerable one, searching for new drugs, displaying anti-glycation and anti-oxidative properties seem useful as an additive therapy of diabetes. In this paper, we assessed the anti-glycating properties of phloroglucinol, a drug discovered in the XIX century and still used in many countries for its antispasmodic action. Herewith, we present its effect on protein glycation, glycoxidation, and oxidative damage in an albumin glycation/oxidation model and HepG2 cells treated with high glucose concentrations. The phloroglucinol showed the strongest and the widest protective effect within all analyzed antiglycating (aminoguanidine, pioglitazone) and anti-oxidative (vitamin C, GSH) agents. To the very best of our knowledge, this is the first study showing the properties of phloroglucinol in vitro what once is proven in other models might deepen its clinical applications.

Pathophysiology of NAFLD and NASH in Experimental Models: The Role of Food Intake Regulating Peptides

Obesity, diabetes, insulin resistance, sedentary lifestyle, and Western diet are the key factors underlying non-alcoholic fatty liver disease (NAFLD), one of the most common liver diseases in developed countries. In many cases, NAFLD further progresses to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and to hepatocellular carcinoma. The hepatic lipotoxicity and non-liver factors, such as adipose tissue inflammation and gastrointestinal imbalances were linked to evolution of NAFLD. Nowadays, the degree of adipose tissue inflammation was shown to directly correlate with the severity of NAFLD. Consumption of higher caloric intake is increasingly emerging as a fuel of metabolic inflammation not only in obesity-related disorders but also NAFLD. However, multiple causes of NAFLD are the reason why the mechanisms of NAFLD progression to NASH are still not well understood. In this review, we explore the role of food intake regulating peptides in NAFLD and NASH mouse models. Leptin, an anorexigenic peptide, is involved in hepatic metabolism, and has an effect on NAFLD experimental models. Glucagon-like peptide-1 (GLP-1), another anorexigenic peptide, and GLP-1 receptor agonists (GLP-1R), represent potential therapeutic agents to prevent NAFLD progression to NASH. On the other hand, the deletion of ghrelin, an orexigenic peptide, prevents age-associated hepatic steatosis in mice. Because of the increasing incidence of NAFLD and NASH worldwide, the selection of appropriate animal models is important to clarify aspects of pathogenesis and progression in this field.

Effect of advanced chelate technology based trace minerals on growth performance, mineral digestibility, tibia characteristics, and antioxidant status in broiler chickens

Background

Compared to the corresponding source of inorganic trace minerals (TM), chelated supplements are characterized by better physical heterogeneity and chemical stability and appear to be better absorbed in the gut due to possibly decreased interaction with other feed components.

Methods

This study was designed in broiler chickens to determine the effects of replacing inorganic trace minerals (TM) with an advanced chelate technology based supplement (Bonzachicken) on growth performance, mineral digestibility, tibia bone quality, and antioxidant status. A total of 625 male 1-day-old broiler chickens were allocated to 25 pens and assigned to 5 dietary treatments in a completely randomized design. Chelated TM (CTM) supplement was compared at 3 levels to no TM (NTM) or inorganic TM. A corn–soy-based control diet was supplemented with inorganic TM at the commercially recommended levels (ITM), i.e., iron, zinc, manganese, copper, selenium, iodine, and chromium at 80, 92, 100, 16, 0.3, 1.2, and 0.1 mg/kg, respectively, and varying concentration of CTM, i.e., match to 25, 50, and 100% of the ITM (diets CTM25, CTM50, and CTM100, respectively).

Results

Diets CTM50 and CTM100 increased average daily gain (ADG), European performance index (EPI), and tibia length compared to the NTM diet (P < 0.05). Broilers fed the CTM100 diet had lowest overall FCR and serum malondialdehyde level and highest EPI, tibia ash, zinc, manganese, and copper contents, and serum total antioxidant capacity (P < 0.05). The apparent ileal digestibilities of phosphorus and zinc were lower in the ITM group compared with the CTM25 and CTM50 groups (P < 0.05). Broiler chickens fed any of the diets, except diet CTM25, exhibited higher serum glutathione peroxidase and superoxide dismutase activities than those fed the NTM diet, where the best glutathione peroxidase activity was found for CTM100 treatment (P < 0.05).

Conclusions

These results indicate that while CTM supplementation to 25 and 50% of the commercially recommended levels could support growth performance, bone mineralization, and antioxidant status, a totally replacing ITM by equivalent levels of CTM could also improve performance index and glutathione peroxidase activity of broiler chickens under the conditions of this study.

Toxicokinetics of methylmercury in diabetic KK-Ay mice and C57BL/6 mice

We compared the toxicokinetics of methylmercury (MeHg) in KK-Ay type 2 diabetic mice and C57BL/6J mice to evaluate how metabolic changes associated with diabetes affect MeHg toxicokinetics. A single dose of MeHg (0.2, 1, or 5 mg mercury/kg) was administered orally to 12-week-old KK-Ay and C57BL/6J male mice. Total mercury concentrations in plasma, blood cells, whole blood, and tissues (brain, kidneys, liver, and pancreas) were measured after 4, 7, 11, and 14 days. The volume of distribution/bioavailability and the elimination rate constant per day were higher in KK-Ay mice, while the terminal elimination half-life was lower in almost all samples of KK-Ay mice. The area under the curve was lower in all blood and almost all tissue samples from KK-Ay mice. Total clearance/bioavailability was lower in all blood and tissue samples of KK-Ay mice at all MeHg doses. These results indicate that MeHg is more rapidly absorbed by, and eliminated from, the blood cells, brain, liver, kidney, and pancreas of KK-Ay mice under the experimental conditions. Different patterns of tissue-to-plasma and tissue-to-whole blood partition coefficients suggest that notable differences in MeHg transfer between plasma and blood cells affect its distribution in tissues of the two mouse strains. These findings are useful to understand the selective distribution of MeHg to target organs and the sensitivity to MeHg in pathological states.

Satellite Cells and Markers of Muscle Regeneration during Unloading and Reloading: Effects of Treatment with Resveratrol and Curcumin

We hypothesized that treatment with pharmacological agents known to increase sirtuin-1 activity (resveratrol and curcumin) may enhance muscle regeneration. In limb muscles of mice (C57BL/6J, 10 weeks) exposed to reloading for seven days following a seven-day period of hindlimb immobilization with/without curcumin or resveratrol treatment, progenitor muscle cell numbers (FACS), satellite cell subtypes (histology), early and late muscle regeneration markers, phenotype and morphometry, sirtuin-1 activity and content, and muscle function were assessed. Treatment with either resveratrol or curcumin in immobilized muscles elicited a significant improvement in numbers of progenitor, activated, quiescent, and total counts of muscle satellite cells, compared to non-treated animals. Treatment with either resveratrol or curcumin in reloaded muscles compared to non-treated mice induced a significant improvement in the CSA of both hybrid (curcumin) and fast-twitch fibers (resveratrol), sirtuin-1 activity (curcumin), sirtuin-1 content (resveratrol), and counts of progenitor muscle cells (resveratrol). Treatment with the pharmacological agents resveratrol and curcumin enhanced the numbers of satellite cells (muscle progenitor, quiescent, activated, and total satellite cells) in the unloaded limb muscles but not in the reloaded muscles. These findings have potential clinical implications as treatment with these phenolic compounds would predominantly be indicated during disuse muscle atrophy to enhance the muscle regeneration process.

Protective Effects of Crocetin on Arsenic Trioxide-Induced Hepatic Injury: Involvement of Suppression in Oxidative Stress and Inflammation Through Activation of Nrf2 Signaling Pathway in Rats

Purpose

Arsenic trioxide (ATO) has been shown to induce hepatic injury. Crocetin is a primary constituent of saffron, which has been verified to have antioxidant and anti-inflammatory effects. In the current experiment, we evaluated the efficacy of crocetin against ATO-induced hepatic injury and explored the potential molecular mechanisms in rats.

Methods

Rats were pretreated with 25 or 50 mg/kg crocetin 6 h prior to treating with 5 mg/kg ATO to induce hepatic injury daily for 7 days.

Results

Treatment with crocetin attenuated ATO-induced body weight loss, decreases in food and water consumption, and improved ATO-induced hepatic pathological damage. Crocetin significantly inhibited ATO-induced alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) increases. Crocetin prevented ATO-induced liver malondialdehyde (MDA) and reactive oxygen species (ROS) levels. Crocetin abrogated the ATO-induced decrease of catalase (CAT) and superoxide dismutase (SOD) activity. Crocetin was found to significantly restore the protein levels of interleukin 6 (IL-6), interleukin 1β (IL-1β), and tumor necrosis factor-alpha (TNF-α). Furthermore, crocetin promoted the expression of nuclear factor erythroid 2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADP(H): quinone oxidoreductase 1 (NQO1).

Conclusion

These findings suggest that crocetin ameliorates ATO-induced hepatic injury in rats. In addition, the effect of crocetin might be related to its role in antioxidant stress, as an anti-inflammatory agent, and in regulating the Nrf2 signaling pathway.

SIRT1-dependent mechanisms and effects of resveratrol for amelioration of muscle wasting in NASH mice

Background

In non-alcoholic steatohepatitis (NASH), muscle wasting was an aggravating factor for the progression of hepatic steatosis. This study explores the potential benefits of chronic treatment with resveratrol, a strong activator of SIRT1 on the muscle wasting of NASH mice.

Methods

In vivo and in vitro study, we evaluate the SIRT1-dependent mechanisms and effects of resveratrol administration for 6 weeks with high-fat-methionine and choline deficient diet-induced NASH mice and palmitate-pretreated C2C12 myoblast cells.

Results

Resveratrol treatment improved grip strength and muscle mass of limbs, increased running distance and time on exercise wheels in NASH mice. There is a negative correlation between muscular SIRT1 activity and 3-nitrotyrosine levels of NASH and NASH-resv mice. The SIRT1-dependent effect of muscle wasting was associated with the suppression of oxidative stress, upregulation of antioxidants, inhibition of protein degradation, activation of autophagy, suppression of apoptotic activity, upregulation of lipolytic genes and the reduction of fatty infiltration in limb muscles of NASH mice. In vitro, resveratrol alleviated palmitate acid-induced oxidative stress, lipid deposition, autophagy dysfunction, apoptotic signals, and subsequently reduced fusion index and myotube formation of C2C12 cells. The beneficial effects of resveratrol were abolished by EX527.

Conclusions

Our study suggests that chronic resveratrol treatment is a potential strategy for amelioration of hepatic steatosis and muscle wasting in NASH mouse model.

Targeting the gut microbiota with resveratrol: a demonstration of novel evidence for the management of hepatic steatosis

Resveratrol is a natural polyphenol that has been reported to reduce the risk of obesity and nonalcoholic fatty liver disease (NAFLD). Recent evidence has demonstrated that the gut microbiota plays an important role in the protection against NAFLD and other metabolic diseases. The present study aimed to investigate the relationship between the gut microbiota and the beneficial effects of resveratrol on the amelioration of NAFLD in mice. We observed marked decreases in body weight and liver steatosis and improved insulin resistance in high-fat diet (HFD)-fed mice treated with resveratrol. Furthermore, we found that resveratrol treatment alleviated NAFLD in HFD-fed mice by improving the intestinal microenvironment, including gut barrier function and gut microbiota composition. On the one hand, resveratrol improved gut intestinal barrier integrity through the repair of intestinal mucosal morphology and increased the expression of physical barrier- and physiochemical barrier-related factors in HFD-fed mice. On the other hand, in HFD-fed mice, resveratrol supplementation modulated the gut bacterial composition. The resveratrol-induced gut microbiota was characterized by a decreased abundance of harmful bacteria, including Desulfovibrio, Lachnospiraceae_NK4A316_group and Alistipes, as well as an increased abundance of short-chain fatty acid (SCFA)-producing bacteria, such as Allobaculum, Bacteroides and Blautia. Moreover, transplantation of the HFDR-microbiota into HFD-fed mice sufficiently decreased body weight, liver steatosis and low-grade inflammation and improved hepatic lipid metabolism. Collectively, resveratrol would provide a potentially dietary intervention strategy against NAFLD through modulating the intestinal microenvironment.

Dietary Garcinol Attenuates Hepatic Pyruvate and Triglyceride Accumulation by Inhibiting P300/CBP-Associated Factor in Mid-to-Late Pregnant Rats

BACKGROUND

Increased hepatic glycolysis and lipogenesis are characteristic of pregnancy.

OBJECTIVES

The present study aimed to investigate the mechanism of garcinol on the amelioration of hepatic pyruvate and triglyceride (TG) accumulation in mid-to-late pregnant rats.

METHODS

Forty Sprague-Dawley pregnant rats (aged 9 wk, n = 10/diet) were fed a basal diet (control) or that diet plus garcinol at 100 ppm (Low Gar), 300 ppm (Mid Gar), or 500 ppm (High Gar) for 14 d. The livers were processed for Western blotting analyses and measuring enzymatic activity and pyruvate and TG concentrations. Hepatocytes from other pregnant Sprague Dawley rats were transfected with P300/CBP associating factor (PCAF) short interfering (si)RNAs; hepatocytes from nonpregnant Sprague-Dawley rats with overexpression of PCAF were treated with garcinol (5 μM). The activity and acetylation of upstream stimulatory factor (USF-1) and glycolytic enzymes were analyzed.

RESULTS

Dietary garcinol significantly decreased (P < 0.05) concentrations of hepatic and plasma TG (27.1-45.8%) and total cholesterol (25.3-49.5%), plasma free fatty acids (24.4-37.8%), and hepatic pyruvate (31.5-43.5%) and lactate (33.4-65.7%) in mid-to-late pregnant rats. Garcinol promoted (P < 0.05) antioxidant capacity in the liver and plasma by 27.4-32.1%. Garcinol downregulated (P < 0.05) lipid synthesis-related enzyme expression by 30.6-85.3% and decreased (P < 0.05) glycolytic enzyme activities by 22.5-74.6% and PCAF activity by 18.6-55.4%. Transfection of PCAF siRNAs to hepatocytes of pregnant rats decreased USF-1 and glycolytic enzyme activities by PCAF; garcinol treatment downregulated (P < 0.05) the acetylation and activities of USF-1 and glycolytic enzymes by 35.6-83.7%.

CONCLUSIONS

Garcinol attenuates hepatic pyruvate and TG accumulation in the liver of mid-to-late pregnant rats, which may be due to downregulating the acetylation of USF-1 and the glycolytic enzymes induced by PCAF in isolated hepatocytes.

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.

Effects of dietary resveratrol supplementation on immunity, antioxidative capacity and intestinal barrier function in weaning piglets

The aim of this study was to investigate effects of dietary supplementation of resveratrol on immunity, antioxidative capacity, intestinal barrier function in weaning piglets. Here, fifty-four 28-day-old Duroc × Landrace × Yorkshire weaning piglets were randomly divided into three dietary treatments and fed with a basal diet or a basal diet supplemented with 150 and 300 mg/kg resveratrol, respectively, for 42 days. The results indicated that resveratrol increased serum immunoglobulin G content. In serum, resveratrol increased glutathione peroxidase enzyme activity and decreased malondialdehyde (MDA) content. In liver, resveratrol not only increased T-AOC and total superoxide dismutase enzyme activities but also decreased MDA content. Meanwhile, the results showed that resveratrol had significantly increased the jejunum villus height and villus height/crypt depth, and decreased the crypt depth in jejunum. Furthermore, the mRNA expressions of IL-10 and ZO-1 were significantly increased in jejunal mucosa. However, there was no significant difference in the mRNA expressions of TNF-α, IL-1β, IL-6, Occludin and Claudin1 between the treatment groups and the control group. Taken together, these results indicated that dietary supplementation of resveratrol could increase antioxidant activity, promote the integrity of intestinal barrier and increase the production of anti-inflammatory cytokines in weaning piglets.

Maslinic acid protects against obesity-induced nonalcoholic fatty liver disease in mice through regulation of the Sirt1/AMPK signaling pathway

Maslinic acid is a pentacyclic triterpenoid that is distributed in the peel of olives. Previous studies found that maslinic acid inhibited inflammatory response and antioxidant effects. We investigated whether maslinic acid ameliorates nonalcoholic fatty liver disease in mice with high-fat-diet (HFD)-induced obesity and evaluated the regulation of lipogenesis in hepatocytes. Male C57BL/6 mice fed a normal diet or HFD (60% fat, w/w) were tested for 16 wk. After the fourth week, mice were injected intraperitoneally with maslinic acid for 12 wk. In another experiment, HepG2 cells were treated with oleic acid to induce lipid accumulation or maslinic acid to evaluate lipogenesis. Maslinic acid significantly reduced body weight compared with HFD-fed mice. Maslinic acid reduced liver weight and liver lipid accumulation and improved hepatocyte steatosis. Furthermore, serum glucose, leptin, and free fatty acid concentrations significantly reduced, but the serum adiponectin concentration was higher, in the maslinic acid group than in the HFD group. In liver tissue, maslinic acid suppressed transcription factors involved in lipogenesis and increased adipose triglyceride lipase. In vitro, maslinic acid decreased lipogenesis by activating AMPK. These findings suggest that maslinic acid acts against hepatic steatosis by regulating enzyme activity involved in lipogenesis, lipolysis, and fatty acid oxidation in the liver.-Liou, C.-J., Dai, Y.-W., Wang, C.-L., Fang, L.-W., Huang, W.-C. Maslinic acid protects against obesity-induced nonalcoholic fatty liver disease in mice through regulation of the Sirt1/AMPK signaling pathway.

The therapeutic effects of resveratrol on hepatic steatosis in high-fat diet-induced obese mice by improving oxidative stress, inflammation and lipid-related gene transcriptional expression

So far, the majority of the previous animal studies have focused on the preventive effects of resveratrol (RSV) on non-alcoholic fatty liver disease (NAFLD) rather than the therapeutic effects. In this study, the therapeutic effects of RSV on hepatic oxidative stress (OS), inflammation, and lipid metabolism-related gene expression of obese mice induced by a high-fat diet (HFD) were investigated. Male C57BL/6 mice were fed a HFD for 8 weeks to induce obesity-related NAFLD model. And then, NAFLD mice were treated with daily RSV oral gavage at the dose of 100 mg/kg body weight for an additional 4 weeks. HFD-induced the elevation of serum total cholesterol, high-density lipoprotein cholesterol, glucose, insulin, aspartate aminotransferase and alanine aminotransferase levels, and homeostasis model assessment of insulin resistance, hepatic histology changes, the increases in hepatic triglyceride, malondialdehyde and tumor necrosis factor alpha concentrations, as well as the higher mRNA expression of hepatic toll-like receptor 4 and cluster of differentiation 36 in mice, were restored by RSV. The therapeutic effects of RSV against hepatic steatosis of HFD obese mice were attributed to the reduction of OS, inflammation and free fatty acid uptake.

Resveratrol regulates skeletal muscle fibers switching through the AdipoR1-AMPK-PGC-1α pathway

This study was conducted to investigate the effect and underlying mechanism of Resveratrol (RES) in regulating skeletal muscle fiber-type switching.

Involvement of 5'-Activated Protein Kinase (AMPK) in the Effects of Resveratrol on Liver Steatosis

This review focuses on the role of 5′AMP-activated protein kinase (AMPK) in the effects of resveratrol (RSV) and some RSV derivatives on hepatic steatosis. In vitro studies, performed in different hepatic cell models, have demonstrated that RSV is effective in preventing liver TG accumulation by activating AMPK, due to its phosphorylation. These preventive effects have been confirmed in studies conducted in animal models, such as mice and rats, by administering the phenolic compound at the same time as the diet which induces TG accumulation in liver. The literature also includes studies focused on other type of models, such as animals showing alcohol-induced steatosis or even steatosis induced by administering chemical products. In addition to the preventive effects of RSV on hepatic steatosis, other studies have demonstrated that it can alleviate previously developed liver steatosis, thus its role as a therapeutic tool has been proposed. The implication of AMPK in the delipidating effects of RSV in in vivo models has also been demonstrated.

Effects of Pharmacologic Dose of Resveratrol Supplementation on Oxidative/Antioxidative Status Biomarkers in Nonalcoholic Fatty Liver Disease Patients: A Randomized, Double-Blind, Placebo-Controlled Trial

Purpose: Despite a proposed role for oxidative stress in the pathogenesis of nonalcoholic fatty liver disease (NAFLD), antioxidant approaches have not been sufficiently investigated in human NAFLD management. Resveratrol has been reported to possess a wide range of biological functions, including antioxidant activities. This study aimed to evaluate the effects of resveratrol supplementation on oxidative/anti-oxidative status in patients with NAFLD.

Methods: This randomized, double-blind, placebo-controlled clinical trial was conducted on 60 patients with NAFLD (males and females) aged 20 to 60 years, and body mass index (BMI) of 25-35 kg/m2. Subjects were randomly assigned to receive a daily dose of 600 mg resveratrol (2×300 mg pure trans-resveratrol capsules; n=30) or placebo capsules (n=30) for 12 wk. Fasting blood samples, anthropometric measurements, and dietary intakes were collected for all patients at baseline and at the end of the trial. Oxidative stress was evaluated by measurement of serum malondialdehyde (MDA), oxidized low-density lipoprotein (ox-LDL), total antioxidant capacity (TAC), and erythrocyte superoxide dismutase (SOD) as well as glutathione peroxidase (GSH-Px) activities. Changes in the outcomes were analyzed using analysis of covariance (ANCOVA).

Results: Resveratrol supplementation did not significantly affect neither serum MDA, ox-LDL, and TAC levels, nor erythrocyte SOD and GSH-Px activities, compared to placebo group (All P>0.05). Moreover, changes in serum levels of liver enzymes (ALT, AST, GGT, and ALP) were not significant in neither of the study groups (All P>0.05).

Conclusion: Resveratrol supplementation did not modify oxidative/anti-oxidative status in patients with NAFLD.

Resveratrol alleviates FFA and CCl4 induced apoptosis in HepG2 cells via restoring endoplasmic reticulum stress

Cell apoptosis often induces inflammation and injury in the liver, with endoplasmic reticulum (ER) stress as the most possible reason. Resveratrol (RSV) has been shown to prevent hepatic steatosis and alleviate apoptosis, however, the exact mechanisms underlying the effects still need to be explored. Here we co-cultured HepG2 cells with free fatty acid (FFA) solution (oleic acid: palmitic acid = 2:1) and then exposed to a carbon tetrachloride (CCl4) solution to induce apoptosis. To evaluate the therapeutic effects, RSV (2.5 μM, 5 μM, 10 μM) was added to the cells. Results showed that HepG2 cells co-cultured with FFA exhibited lipid infiltration and were susceptible to apoptosis upon exposure to the CCl4 solution. The expression of molecules related to apoptosis (Caspases, Bcl-2/Bax) and ER stress (GRP78, IRE1, ATF6, PERK, et al.) was all significantly decreased upon RSV treatment. We further inhibited GRP78 by siRNA, results showed that the anti-apoptotic effect of RSV still maintained under GRP78 siRNA condition. Our data demonstrated that lipid accumulated HepG2 cells were susceptible to injury, and RSV could improve apoptosis in FFA and CCl4 stressed cells, which partially via restoring ER function.

Resveratrol improves glucose uptake in insulin-resistant adipocytes via Sirt1

Insulin resistance serves as "common soil" for promoting the development of metabolic diseases; however, the precise pathological factors leading to insulin resistance are not well clarified. Resveratrol (Res) is a natural polyphenolic compound with anti-inflammatory and antioxidative effects. However, effects and mechanisms of Res on glucose metabolism in adipocytes remain largely unknown. In this study, we show Res treatment significantly increases glucose uptake in insulin-resistant 3T3-L1 adipocytes in vitro. Mechanistically, Res up-regulates the protein level of Sirt1 that improves insulin signaling pathway and promotes cellular membrane Glut4 accumulation. Meanwhile, Sirt1 enhances phosphorylation level of AMPK which elevates p-AKT level. Consequently, the transcription factor FOXO1 translocalizes from nucleus to cytoplasm where protein degradation occurs. Therefore, the gene expression of resistin, a direct transcriptional target of FOXO1, is reduced and insulin sensitivity is improved. Importantly, we recapitulate the similar pattern of related protein changes in epididymal adipose tissues of insulin-resistant mice after Res intervention in vivo, reinforcing the hypothesis of Res being involved in regulation of glucose uptake via Sirt1-AMPK axis. Our findings clarify the beneficial effects of Res on glucose transportation in insulin-resistant adipocytes and involved pathway including Sirt1-AMPK, suggesting its potential therapeutic application in the treatment or prevention of insulin-resistance-related metabolic symptoms.

Effect of dietary resveratrol supplementation on meat quality, muscle antioxidative capacity and mitochondrial biogenesis of broilers

BACKGROUND

The naturally occurring polyphenol resveratrol has been acknowledged with many beneficial biological effects. The aim of this study was to evaluate the influence of dietary resveratrol supplementation on meat quality, muscle antioxidative capacity and mitochondrial biogenesis of broilers. One hundred and eighty 21-day-old male Cobb broilers were randomly assigned to two groups and fed on a 0 mg kg^-1 or 400 mg kg^-1 resveratrol-supplemented diet for 21 days. Then, chickens were slaughtered and pectoralis major muscle (PM) samples were collected for analysis.

RESULTS

The results showed that resveratrol not only tended to increase (P < 0.10) PM pH_24h but also significantly decreased (P < 0.05) PM L*_45min , pH decline, drip loss and lactate content. Meanwhile, PM total antioxidative capacity and catalase activity were significantly increased (P < 0.05) by resveratrol, while malondialdehyde content was decreased (P < 0.10). Moreover, resveratrol significantly increased (P < 0.05) PM peroxisome proliferator-activated receptor γ coactivator 1α and nuclear respiratory factor 1 mRNA levels, along with increased (P < 0.05) citrate synthase activity.

CONCLUSION

Resveratrol can be used as a feed additive to improve meat quality of broilers, which may be associated with improved muscle antioxidative status and mitochondrial biogenesis. © 2017 Society of Chemical Industry.

Involvement of autophagy in the beneficial effects of resveratrol in hepatic steatosis treatment. A comparison with energy restriction

Involvement of autophagy in the liver delipidating effects of resveratrol and energy restriction.

Metabolism and pharmacokinetics of resveratrol and pterostilbene

Beneficial properties of resveratrol and pterostilbene, a dimethyl ether analog of resveratrol, have attracted increasing interest in recent years. Resveratrol and pterostilbene exhibit many pharmacological similarities and both of them are generally considered to be safe for human consumption. Beyond the structural and general bioactivity similarities between them, large amounts of data are now available to reveal the metabolic fate and pharmacological differences between them. Pterostilbene was found to be more metabolically stable and usually exhibited stronger pharmacological activities than that of resveratrol. As a contribution to clarify and compare aspects like metabolic stability and pharmacokinetics of resveratrol and pterostilbene, as well as explain the pharmacological similarities and differences between them, this review presents and compares recent data on the metabolism and pharmacokinetics of resveratrol and pterostilbene. © 2018 BioFactors, 44(1):16-25, 2018.

Resveratrol inhibits age-dependent spontaneous tumorigenesis by SIRT1-mediated post-translational modulations in the annual fish Nothobranchius guentheri

Resveratrol, SIRT1 activator, inhibits carcinogenesis predominantly performed in transgenic animal models, orthotopic cancers of nude mice or different cancer cell lines, but its effects during process of spontaneous tumors using vertebrate models remain untested. Spontaneous liver neoplasm is an age-related disease and is inhibited by resveratrol in the annual fish Nothobranchius guentheri, which indicates that the fish can act as an excellent model to study spontaneous tumorigenesis. Totally, 175 fish were fed with resveratrol and another 175 fish for controls. Treated fish were fed with resveratrol (25 μg/fish/day) from sexual maturity (4-month-old) until they were sacrificed at 6-, 9- and 12-month-old. Immunoblot, immunohistochemistry and co-immunoprecipitation were employed to investigate the underlying mechanisms that resveratrol inhibited age-dependent spontaneous tumorigenesis in the fish. Results showed that resveratrol increased protein level of SIRT1 and alleviated age-associated tumorigenesis in liver. With SIRT1 up-regulation, resveratrol reduced proliferation by deacetylating K-Ras and inactivating K-Ras/PI3K/AKT pathway; and promoted apoptosis through deacetylation and dephosphorylation of FoxOs, up-regulation of DLC1 and interaction between SIRT1 and DLC1, and dephosphorylation of DLC1 in spontaneous neoplasms. We established a novel short-lived fish model for understanding the molecular mechanisms of drugs on age-dependent spontaneous tumorigenesis.

Oxidative stress and food supplementation with antioxidants in therapy dogs

The objective of this study was to evaluate the ability of a long-term antioxidant-supplemented diet to regulate the oxidative stress and general health status of dogs involved in animal-assisted intervention (AAI) programs. Oxidative stress is a consequence of the accumulation of reactive oxygen species (ROS). Exercise-induced oxidative stress can increase muscle fatigue and fiber damage and eventually leads to impairment of the immune system. A randomized, placebo-controlled, crossover clinical evaluation was conducted with 11 healthy therapy dogs: 6 females and 5 males of different breeds and with a mean age of 2.7 ± 0.8 y (mean ± SEM). The dogs were divided into 2 groups, 1 fed a high quality commercial diet without antioxidants (CD) and the other a high quality commercial diet supplemented with antioxidants (SD) for 18 wk. After the first 18 wk, metabolic parameters, reactive oxygen metabolite-derivatives (d-ROMs), and biological antioxidant potential (BAP) levels were monitored and showed a significant reduction of d-ROMs, triglycerides, and creatinine values in the SD group (P < 0.05) and a significant increase in amylase values in the CD group (P < 0.01). At the end of this period, groups were crossed over and fed for another 18 wk. A significant decrease in amylase and glutamate pyruvate transaminase (GPT) values was observed in the CD and SD group, respectively (P < 0.05). In conclusion, a controlled, balanced antioxidant diet may be a valid approach to restoring good cell metabolism and neutralizing excess free radicals in therapy dogs.

Diet-induced non-alcoholic fatty liver disease affects expression of major cytochrome P450 genes in a mouse model

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is associated with impaired liver function, and resveratrol could suppress NAFLD progression. This study examined the effects of NAFLD on the expression of major cytochrome P450 (CYP) subtypes in the liver and whether the expression could be attenuated by resveratrol.

METHODS

C57BL/6 mice (male, 10 weeks of age) were fed a high-fat and high-sucrose (HFHS) diet to induce NAFLD. Major Cyp subtype mRNA expression in the liver was measured by real-time RT-PCR.

KEY FINDINGS

Body and liver weights at 4 and 12 weeks were significantly higher in mice fed the HFHS diet compared with control. The HFHS diet significantly increased the accumulation of cholesterol and triglycerides at 12 weeks. Under this condition, the HFHS diet increased the expression of Cyp1a2 and decreased that of Cyp3a11 at 1 week and thereafter. On the other hand, Cyp1a1, 2b10 and 2c29 mRNA expression levels in the liver were significantly increased at 12 weeks only. Resveratrol (0.05% (w/w) in diet) slightly suppressed lipid accumulation in the liver, but failed to recover impaired Cyp gene expression levels in NAFLD.

CONCLUSIONS

Drug metabolism may be impaired in NAFLD, and each Cyp subtype is regulated in a different manner.