Resveratrol attenuates against high-fat-diet-promoted non-alcoholic fatty liver disease in rats mainly by targeting the miR-34a/SIRT1 axis

This study evaluated if miR-34a/SIRT1 signalling mediates the anti-hepatosteatotic effect of resveratrol (RSV) in high-fat-diet (HFD)-fed rats. Rats were divided into seven groups (n = 6/each) as control, control + miR-34a agomir negative control, HFD, HFD + miR-34a, HFD + RSV, HFD + RSV + Ex-527 (a SIRT1 inhibitor), and HFD + RSV + miR-34a agomir. After 8 weeks, RSV suppressed dyslipidemia, lowered fasting glucose and insulin levels, improved insulin sensitivity, and prevented hepatic lipid accumulation. These effects were associated with hepatic downregulation of SREBP1 and SREBP2, upregulation of PPARα, and acetylation of Nrf2 (activation) and NF-κβ p65 (inhibition). Also, RSV reduced the transcription of miR-34a and increased the nuclear localisation of SIRT1 in the livers, muscles, and adipose tissues of HFD-fed rats. All these effects were prevented by EX-527 and miR-34a agmir. In conclusion, RSV prevents HFD-induced insulin resistance and hepatic steatosis by suppressing miR-34a-induced activation of SIRT1.

Ameliorative effects of aqueous extract from rosemary on oxidative stress and inflammation pathways caused by a high-fat diet in C57BL/6 mice

Rosemary is an herb exhibits biological properties, attenuates inflammation, oxidative stress, and improves lipid profile. Here, we evaluated the effects of rosemary aqueous extract (RE) on mice fed with a high-fat diet (HFD). Male C57BL/6 mice were administered a control diet or HFD for 10 weeks. The treated groups received RE in the diet at different concentrations: 25, 250, and 500 mg/100 g. After 10 weeks, serum concentrations of glucose, lipid, insulin, leptin, adiponectin, and cytokines were evaluated and the oxygen radical absorbance capacity was determined. Histological analysis was performed to determine the concentrations of triacylglycerides (TG), total cholesterol, cytokines, and antioxidant enzymes as well as the expression of genes involved in lipid metabolism, oxidative stress, and inflammation. The dietary RE ameliorated HFD-induced weight gain, adipose tissue weight, glucose intolerance, and insulin, leptin, and free fatty acid levels. Reduction in hepatic TG deposition was observed. The levels of inflammatory cytokines decreased, and the expression of genes involved in lipid metabolism increased. RE mitigated oxidative stress and reduced the production of reactive oxygen species in HepG2 and 3T3-L1 cells. Therefore, RE is a potential therapeutic agent for the prevention of inflammation and oxidative stress outcomes associated with obesity.

Does Resveratrol Improve Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)?

Metabolic dysfunction-associated steatotic liver disease (MASLD) is influenced by a variety of factors, including environmental and genetic factors. The most significant outcome is the alteration of free fatty acid and triglyceride metabolism. Lipotoxicity, impaired autophagy, chronic inflammation, and oxidative stress, as well as coexisting insulin resistance, obesity, and changes in the composition of gut microbiota, are also considered crucial factors in the pathogenesis of MASLD. Resveratrol is a polyphenolic compound that belongs to the stilbene subgroup. This review summarises the available information on the therapeutic effects of resveratrol against MASLD. Resveratrol has demonstrated promising antisteatotic, antioxidant, and anti-inflammatory activities in liver cells in in vitro and animal studies. Resveratrol has been associated with inhibiting the NF-κB pathway, activating the SIRT-1 and AMPK pathways, normalizing the intestinal microbiome, and alleviating intestinal inflammation. However, clinical studies have yielded inconclusive results regarding the efficacy of resveratrol in alleviating hepatic steatosis or reducing any of the parameters found in MASLD in human patients. The lack of homogeneity between studies, low bioavailability of resveratrol, and population variability when compared to animal models could be the reasons for this.

Korean red ginseng formula attenuates non-alcoholic fatty liver disease in oleic acid-induced HepG2 cells and high-fat diet-induced rats

Objective

Non-alcoholic fatty liver disease (NAFLD) is the leading chronic liver disease. We have developed a Korean Red Ginseng Formula (KRGF) containing extracts of Korean Red Ginseng (KRG), Crataegus Fructus, and Cassiae Semen. In this study, our aims were to investigate the therapeutic potential and underpinning mechanisms of KRGF in NAFLD complicated by hyperlipidemia.

Methods

In the in vitro assays, HepG2 cells were treated with KRGF for 24 h in the presence or absence of oleic acid (OA). To assess the in vivo protective effect of KRGF against NAFLD, rats fed a high-fat diet (HFD) were given intragastric administration for 30 days.

Results

KRGF exerted protective effects against NAFLD by reducing lipid accumulation and steatosis in OA-stimulated HepG2 cells and HFD-fed rats. In HFD-fed rats, KRGF effectively decreased triglyceride levels in both blood and liver tissue and modulated the expression of key regulators of lipogenesis and fatty acid oxidation. KRGF downregulated the expression of lipogenesis factors, namely C/EBPα, FAS, SREBP-1c, and PPARγ, while upregulating the expression of PPARα and CPT-1, thus promoting fatty acid oxidation. Additionally, KRGF intensified the phosphorylation of AMPK and ACC, which are two enzymes that suppress fatty acid synthesis and promote fatty acid oxidation. KRGF effectively decreased total cholesterol (TC) levels in both blood and liver tissue, and it modulated the expression of major enzymes related to TC metabolism, namely apoB, ACAT2, CYP7A1, and HMGCR.

Conclusion

In conclusion, KRGF mitigated NAFLD complicated by hyperlipidemia by modulating triglyceride and cholesterol metabolism, suggesting its potential for future development in the treatment of NAFLD.

Si-Ni-San reduces lipid droplet deposition associated with decreased YAP1 in metabolic dysfunction-associated fatty liver disease

ETHNOPHARMACOLOGICAL RELEVANCE

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide. However, its complex pathogenesis and lack of effective drugs for treating it present significant challenges. Si-Ni-San (SNS) is one of the representative formulas for treating patients with MAFLD in traditional Chinese medicine (TCM) clinics. According to our previous work, SNS reduces lipid droplet (LD) deposition in livers of mice with MAFLD.

AIM OF THE STUDY

To elucidate the mechanism of SNS in reducing LD deposition in MAFLD.

MATERIALS AND METHODS

First, LD areas were detected with Oil red O staining in HepG2 cells induced by oleic acid (OA). Cell Counting Kit-8 (CCK-8) assay was used to test cell viability after treatment with different concentrations of SNS serum. The expression of Yes-associated protein 1 (YAP1) was monitored by Western blot. Second, C57BL/6 mice were fed a high-fat diet (HFD) for 12 weeks and gavaged with SNS decoction during the 11th and 12th weeks. Then, the weight of the body and the liver was examined. LD numbers and their locations in the liver were detected by triglyceride (TG) assay and hematoxylin and eosin staining (H&E). The expression levels of YAP1 and perilipin2 (PLIN2) were detected using Western blot and immunohistochemistry (IHC) in liver tissues. Finally, active ingredients of SNS decoction and SNS serum were identified by liquid chromatography-mass spectrometry (LC-MS). Finally, molecular docking was performed between the compounds in SNS and YAP1 to analyze their active interaction.

RESULTS

Cellular experiments showed that SNS serum reduced LD vacuoles and YAP1 expression in OA-induced HepG2 cells. Animal experiments confirmed that LD vacuoles, PLIN2 expression (3.16-fold), and YAP1 expression (2.50-fold) were increased in the HFD group compared with the normal diet (ND) group. SNS reduced LD vacuoles, TG content (0.84-fold), PLIN2 expression (0.33-fold), and YAP1 expression (0.27-fold) compared with the normal saline (NS) group in Yap1^Flox mice with MAFLD. In SNS, baicalein-6-glucuronide, desoxylimonin, galangin-7-glucoside, glycyrrhizic-acid, licoricesaponin-K2, and nobiletin showed a high binding effect with YAP1. Knockout of hepatocyte YAP1 reduced LD vacuoles, TG content (0.40-fold), and PLIN2 expression (0.62-fold) in mice. Meanwhile, SNS reduced LD vacuoles, TG content (0.70-fold), and PLIN2 expression (0.19-fold) in Yap1^LKO mice with MAFLD. The effect of SNS in reducing TG and PLIN2 was diminished in Yap1^LKO mice compared with Yap1^Flox mice.

CONCLUSION

SNS reduced LD deposition and YAP1 expression in MAFLD liver cells both in vivo and in vitro. YAP1 was highly expressed in livers with MAFLD, and knockout of hepatocellular YAP1 reduced LD deposition in mice. SNS reduced LD deposition associated with decreased YAP1 in MAFLD liver cells.

Synergistic activation of AMPK by AdipoR1/2 agonist and inhibitor of EDPs-EBP interaction recover NAFLD through enhancing mitochondrial function in mice

Nonalcoholic fatty liver disease (NAFLD), especially nonalcoholic steatohepatitis (NASH), is a common hepatic manifestation of metabolic syndrome. However, there are no effective therapy to treat this devastating disease. Accumulating evidence suggests that the generation of elastin-derived peptides (EDPs) and the inhibition of adiponectin receptors (AdipoR)1/2 plays essential roles in hepatic lipid metabolism and liver fibrosis. We recently reported that the AdipoR1/2 dual agonist JT003 significantly degraded the extracellular matrix (ECM) and ameliorated liver fibrosis. However, the degradation of the ECM lead to the generation of EDPs, which could further alter liver homeostasis negatively. Thus, in this study, we successfully combined AdipoR1/2 agonist JT003 with V14, which acted as an inhibitor of EDPs-EBP interaction to overcome the defect of ECM degradation. We found that combination of JT003 and V14 possessed excellent synergistic benefits on ameliorating NASH and liver fibrosis than either alone since they compensate the shortage of each other. These effects are induced by the enhancement of the mitochondrial antioxidant capacity, mitophagy, and mitochondrial biogenesis via AMPK pathway. Furthermore, specific suppression of AMPK could block the effects of the combination of JT003 and V14 on reduced oxidative stress, increased mitophagy and mitochondrial biogenesis. These positive results suggested that this administration of combination of AdipoR1/2 dual agonist and inhibitor of EDPs-EBP interaction can be recommended alternatively for an effective and promising therapeutic strategy for the treatment of NAFLD and NASH related fibrosis.

Nocellara Del Belice (Olea europaea L. Cultivar): Leaf Extract Concentrated in Phenolic Compounds and Its Anti-Inflammatory and Radical Scavenging Activity

Olea europaea L. is a plant belonging to the Oleaceae family, widely grown around the Mediterranean Basin and its leaves are a source of phenolic compounds with antioxidant and anti-inflammatory capacity. Among these, oleuropein and luteolin-7-O-glucoside represent two major polyphenolic compounds in olive-leaf extract. Herein, a polystyrene resin was used to recover the polyphenolic fraction from the acetone-water leaf extract from Nocellara del Belice cultivar, which showed the higher level of analysed bioactive compounds, compared to Carolea cultivar. The antioxidant activity of the extract concentrated in phenolic compounds (OLECp) was evaluated through a classical assay and electron paramagnetic resonance (EPR) for DPPH and hydroxyl radicals scavenging. Thus, the anti-inflammatory activity and the potential beneficial effects in reducing lipid accumulation in an in vitro model of NAFLD using McA-RH7777 cells exposed to oleic acid (OA) were evaluated. Nile Red and Oil Red O have been used to stain the lipid accumulation, while the inflammatory status was assessed by Cytokines Bioplex Assay. OLECp (TPC: 92.93 ± 9.35 mg GAE/g, TFC: 728.12 ± 16.04 mg RE/g; 1 g of extract contains 315.250 mg of oleuropein and 17.44 mg of luteolin-7-O-glucoside) exerted a good radical scavenging capability (IC₅₀: 2.30 ± 0.18 mg/mL) with a neutralizing power against DPPH and hydroxyl radicals, as confirmed by the decreased signal area of the EPR spectra. Moreover, OLECp at concentration of 25, 50 and 100 μg/mL counteracted the intracellular inflammatory status, as result of decreased intracellular lipid content. Our results highlighted the multiple properties and applications of an O. europaea extract concentrated in polyphenols, and the possibility to formulate novel nutraceuticals with antioxidant properties, destined to ameliorate human health.

Topical administration of pterostilbene accelerates burn wound healing in diabetes through activation of the HIF1α signaling pathway

Impaired wound healing is one of a variety of severe diabetic complications and involves many factors, including consistent oxidative stress, prolonged inflammation, impaired angiogenesis, and delayed re-epithelialization. Despite the severe negative impacts that impaired wound healing has on patients' lives, detailed mechanisms and effective therapies are still not fully developed. In this study, we aim to investigate the potential effects and mechanisms of topical administration of pterostilbene and resveratrol on burn wound healing in diabetes. Our in vitro experiments in human umbilical vein endothelial cells showed that long term exposure of hyperglycemia induces oxidative stress and suppression of hypoxia inducible factor1α (HIF1α) signaling pathway, and pterostilbene treatment completely, while resveratrol treatment partly, reversed this effect. Further in vivo experiments in diabetic rats showed that topical administration of pterostilbene exhibited stronger efficacy than resveratrol in normalizing oxidative stress, HIF1α activity, and accelerating burn wound healing in diabetes. We conclude that topical administration of pterostilbene accelerates burn wound healing in diabetes through activation of the HIF1α signaling pathway; thus, pterostilbene may be a potential candidate for clinical treatment of burn wound healing in diabetes.

Modulation of Oxidative Stress-Induced Senescence during Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is characterized by disturbed lipid metabolism and increased oxidative stress. These conditions lead to the activation of different cellular response mechanisms, including senescence. Cellular senescence constitutes an important response to injury in the liver. Recent findings show that chronic oxidative stress can induce senescence, and this might be a driving mechanism for NAFLD progression, aggravating the disturbance of lipid metabolism, organelle dysfunction, pro-inflammatory response and hepatocellular damage. In this context, the modulation of cellular senescence can be beneficial to ameliorate oxidative stress-related damage during NAFLD progression. This review focuses on the role of oxidative stress and senescence in the mechanisms leading to NAFLD and discusses the possibilities to modulate senescence as a therapeutic strategy in the treatment of NAFLD.

A Molecular Insight into the Role of Antioxidants in Nonalcoholic Fatty Liver Diseases

Nonalcoholic fatty liver disease (NAFLD) defines fat accumulation in the liver, and it is commonly associated with metabolic syndromes like diabetes and obesity. Progressive NAFLD leads to nonalcoholic steatohepatitis (NASH) and ultimately causes cirrhosis and hepatocellular carcinoma, and NASH is currently a frequent cause of liver transplantation. Oxidative stress is often contributed to the progression of NAFLD, and hence, antioxidants such as silymarin, silybin, or silibinin, pentoxifylline, resveratrol, and vitamins A, C, and E are used in clinical trials against NAFLD. Silymarin induces the peroxisome proliferator-activated receptor α (PPARα), a fatty acid sensor, which promotes the transcription of genes that are required for the enzymes involved in lipid oxidation in hepatocytes. Silybin inhibits sterol regulatory element-binding protein 1 and carbohydrate response element-binding protein to downregulate the expression of genes responsible for de novo lipogenesis by activating AMP-activated protein kinase phosphorylation. Pentoxifylline inhibits TNF-α expression and endoplasmic reticulum stress-mediated inflammatory nuclear factor kappa B (NF-κB) activation. Thus, it prevents NAFLD to NASH progression. Resveratrol inhibits methylation at Nrf-2 promoters and NF-κB activity via SIRT1 activation in NAFLD conditions. However, clinically, resveratrol has not shown promising beneficial effects. Vitamin C is beneficial in NAFLD patients. Vitamin E is not effectively regressing hepatic fibrosis. Hence, its combination with antifibrotic agents is used as an adjuvant to produce a synergistic antifibrotic effect. However, to date, none of these antioxidants have been used as a definite therapeutic agent in NAFLD patients. Further, these antioxidants should be studied in NAFLD patients with larger populations and multiple endpoints in the future.

Application of herbs and active ingredients ameliorate non-alcoholic fatty liver disease under the guidance of traditional Chinese medicine

Non-alcoholic fatty liver disease (NAFLD) is a global health problem, and its prevalence has been on the rise in recent years. Traditional Chinese Medicine (TCM) contains a wealth of therapeutic resources and has been in use for thousands of years regarding the prevention of liver disease and has been shown to be effective in the treatment of NAFLD in China. but the molecular mechanisms behind it have not been elucidated. In this article, we have updated and summarized the research and evidence concerning herbs and their active ingredients for the treatment in vivo and vitro models of NAFLD or NASH, by searching PubMed, Web of Science and SciFinder databases. In particular, we have found that most of the herbs and active ingredients reported so far have the effect of clearing heat and dispelling dampness, which is consistent with the concept of dampness-heat syndrome, in TCM theory. we have attempted to establish the TCM theory and modern pharmacological mechanisms links between herbs and monomers according to their TCM efficacy, experiment models, targets of modulation and amelioration of NAFLD pathology. Thus, we provide ideas and perspectives for further exploration of the pathogenesis of NAFLD and herbal therapy, helping to further the scientific connotation of TCM theories and promote the modernization of TCM.

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.

The Emerging Role of Nanomedicine in the Management of Nonalcoholic Fatty Liver Disease: A State-of-the-Art Review

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease that can lead to end-stage liver disease needing a liver transplant. Many pharmacological approaches are used to reduce the disease progression in NAFLD. However, current strategies remain ineffective to reverse the progression of NAFLD completely. Employing nanoparticles as a drug delivery system has demonstrated significant potential for improving the bioavailability of drugs in the treatment of NAFLD. Various types of nanoparticles are exploited in this regard for the management of NAFLD. In this review, we cover the current therapeutic approaches to manage NAFLD and provide a review of recent up-to-date advances in the uses of nanoparticles for the treatment of NAFLD.

Effects of Oral Vitamin C Supplementation on Liver Health and Associated Parameters in Patients With Non-Alcoholic Fatty Liver Disease: A Randomized Clinical Trial

Non-alcoholic fatty liver disease (NAFLD) is now recognized as the most prevalent hepatic disorder worldwide, and an unhealthy lifestyle is the leading risk factor for its occurrence. Vitamin C (VC) has been suggested to protect NAFLD, whereas evidence from randomized controlled trials (RCTs) is sparse. In this study, we aimed to investigate the potential benefits of VC supplementation daily on liver health and associated parameters in patients with NAFLD. In this double-blind, RCT, 84 patients with NAFLD, aged 18-60 years old, were assigned to 12 weeks of oral treatment with either low (250 mg/day, n = 26), medium (1,000 mg/day, n = 30), or high (2,000 mg/day, n = 28) doses of VC supplements. After the intervention, the Medium group had a more significant decrease in aspartate aminotransferase [Medium, -5.00 (-10.25, -1.75) vs. High, -2.50 (-7.75, 0.00), P = 0.02] and alanine aminotransferase [Medium, -8.00 (-18.00, -1.75) vs. High, -3.50 (-13.75, 4.25), P = 0.05; Medium vs. Low, -3.00 (-9.00, 5.50), P = 0.031]. The levels of other indicators of liver health, such as gamma-glutamyl transferase, alkaline phosphatase, total bilirubin, and direct bilirubin were decreased after the intervention but comparable among the three groups and so did the parameters of glucose metabolism, such as fasting insulin, fasting glucose, and homeostasis model assessment for insulin resistance. The plasma level of VC in patients and total adiponectin and high molecular weight (HMW) adiponectin levels were also elevated but not in a dose-dependent manner. Meanwhile, analysis of fecal microbiota composition showed an increase in the alpha diversity (Abundance-based Coverage Estimator (ACE), Shannon, chao1, and Simpson) both in the Low and the Medium groups. A total of 12 weeks of VC supplementation, especially 1,000 mg/day, improved liver health and glucose metabolism in patients with NAFLD. The elevated plasma levels of VC, total and HMW adiponectin, and the improvement of intestinal microbiota may have made some contributions.

Lily bulbs' polyphenols extract ameliorates oxidative stress and lipid accumulation in vitro and in vivo

BACKGROUND

Polyphenols have the potential to reduce the risk of many metabolic disorders. Lily bulbs are rich in polyphenols; however, their effects on lipid metabolism remain unclear. This study aimed to explore the effects of lily bulbs' polyphenols (LBPs) on oxidative stress and lipid metabolism.

RESULTS

A total of 14 polyphenolic compounds in LBPs were identified by high-performance liquid chromatography equipped with diode-array detection mass spectrometry. Total phenolic compound in LBPs was 53.76 ± 1.12 g kg^-1 dry weight. In cellular experiments, LBPs attenuated the disruption of mitochondrial membrane potential, impeded reactive oxygen species production, alleviated oxidative stress, and reduced lipid accumulation in oleic acid induced HepG2 cells. In in vivo studies, LBPs significantly inhibited body weight gain, reduced lipid levels in serum and liver, and improved oxidative damage in a dose-dependent manner in mice fed a high-fat diet. Moreover, LBPs ameliorated hepatic steatosis and suppressed the expression of hepatic-lipogenesis-related genes (SREBP-1c, FAS, ACC1, and SCD-1) and promoted lipolysis genes (SRB1 and HL) and lipid oxidation genes (PPARα and CPT-1) in mice fed a high-fat diet.

CONCLUSION

It was concluded that LBPs are a potential complementary therapeutic alternative in the development of functional foods to curb obesity and obesity-related diseases, such as metabolic syndrome. © 2021 Society of Chemical Industry.

HBV Pre-S1-Derived Myristoylated Peptide (Myr47): Identification of the Inhibitory Activity on the Cellular Uptake of Lipid Nanoparticles

The Myr47 lipopeptide, consisting of hepatitis B virus (HBV) pre-S1 domain (myristoylated 2–48 peptide), is an effective commercialized anti-HBV drug that prevents the interaction of HBV with sodium taurocholate cotransporting polypeptide (NTCP) on human hepatocytes, an activity which requires both N-myristoylation residue and specific amino acid sequences. We recently reported that Myr47 reduces the cellular uptake of HBV surface antigen (HBsAg, subviral particle of HBV) in the absence of NTCP expression. In this study, we analyzed how Myr47 reduces the cellular uptake of lipid nanoparticles (including liposomes (LPs) and HBsAg) without NTCP expression. By using Myr47 mutants lacking the HBV infection inhibitory activity, they could reduce the cellular uptake of LPs in an N-myristoylation-dependent manner and an amino acid sequence-independent manner, not only in human liver-derived cells but also in human non-liver-derived cells. Moreover, Myr47 and its mutants could reduce the interaction of LPs with apolipoprotein E3 (ApoE3) in an N-myristoylation-dependent manner regardless of their amino acid sequences. From these results, lipopeptides are generally anchored by inserting their myristoyl residue into the lipid bilayer and can inhibit the interaction of LPs/HBsAg with apolipoprotein, thereby reducing the cellular uptake of LPs/HBsAg. Similarly, Myr47 would interact with HBV, inhibiting the uptake of HBV into human hepatic cells, while the inhibitory effect of Myr47 may be secondary to its ability to protect against HBV infection.

Knockdown of insulin-like growth factor 2 gene disrupts mitochondrial functions in the liver

Even though insulin-like growth factor 2 (IGF2) has been reported to be overexpressed in nonalcoholic fatty liver disease (NAFLD), its role in the progression of NAFLD and the potential mechanism remain largely unclear. Using in vitro models, we found that IGF2 was the key overexpressed gene in steatosis, suggesting a possible association between IGF2 and NAFLD. Interestingly, loss-of-function experiments revealed that inhibition of IGF2 protein impaired mitochondrial biogenesis and respiration. It additionally disrupted the expression changes of mitochondrial fusion and fission-related proteins necessary in maintaining mitochondrial homeostasis. Consistently, IGF2 knockdown reduced the mitochondrial membrane potential and increased the production of reactive oxygen species. Mechanistically, IGF2 regulates mitochondrial functions by modulating the expression of SIRT1 and its downstream gene PGC1α. This research opens a new frontier on the role of IGF2 in energy metabolism, which potentially participates in the development of NAFLD. As such, IGF2 is a potential therapeutic target against NAFLD.

The Role of Resveratrol in Liver Disease: A Comprehensive Review from In Vitro to Clinical Trials

Many studies have shown that resveratrol has a lot of therapeutic effects on liver disorders. Its administration can significantly increase the survival rate after liver transplantation, reduce fat deposition and ischemia-induced necrosis and apoptosis in Wistar rats. Resveratrol can provide Liver protection against chemical, cholestatic, and alcohol-mediated damage. It can improve glucose metabolism and lipid profile, reduce liver fibrosis, and steatosis. Additionally, it is capable of altering the fatty acid composition of the liver cells. Resveratrol may be a potential treatment option for the management of non-alcoholic fatty liver disease (NAFLD) due to its anti-inflammatory, antioxidant, and calorie-restricting effects. There are also studies that have evaluated the effect of resveratrol on lipid and liver enzyme profiles among patients with metabolic syndrome (MetS) and related disorders. Based on the extent of liver disease worldwide and the need to find new treatment possibilities, this review critically examines current in vitro and in vivo preclinical studies and human clinical studies related to liver protection.

Research progress in use of traditional Chinese medicine monomer for treatment of non-alcoholic fatty liver disease

With the improvement of people's living standards and the change of eating habits, non-alcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. However, there are no effective drugs for the treatment of NAFLD. Therefore, it is urgent to find safe, efficient, and economical anti-NAFLD drugs. Compared with western medicines that possess fast lipid-lowering effect, traditional Chinese medicines (TCM) have attracted increasing attention for the treatment of NAFLD due to their unique advantages such as multi-targets and multi-channel mechanisms of action. TCM monomers have been proved to treat NAFLD through regulating various pathways, including inflammation, lipid production, insulin sensitivity, mitochondrial dysfunction, autophagy, and intestinal microbiota. In particular, peroxisome proliferator-activated receptor α (PPAR-α), sterol regulatory element-binding protein 1c (SREBP-1c), nuclear transcription factor kappa (NF-κB), phosphoinositide 3-kinase (PI3K), sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), p53 and nuclear factor erythroid 2-related factor 2 (Nrf2) are considered as important molecular targets for ameliorating NAFLD by TCM monomers. Therefore, by searching PubMed, Web of Science and SciFinder databases, this paper updates and summarizes the experimental and clinical evidence of TCM monomers for the treatment of NAFLD in the past six years (2015-2020), thus providing thoughts and prospects for further exploring the pathogenesis of NAFLD and TCM monomer therapies.

Veratrilla baillonii Franch Could Alleviate Lipid Accumulation in LO2 Cells by Regulating Oxidative, Inflammatory, and Lipid Metabolic Signaling Pathways

Based on the pathological theory of lipid metabolism and using network pharmacology, this study was designed to investigate the protective effect of water extract of Veratrilla baillonii (WVBF) on non-alcoholic fatty liver disease (NAFLD) model using LO2 cells and to identify the potential mechanism underlying the effect. The components of V. baillonii were identified from the public database of traditional Chinese medicine systems pharmacology database (TCMSP). Cytoscape software was used to construct the related composite target network. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were carried out for critical nodes. The BioGPS database was used to determine the distribution of the target in tissues and organs. Moreover, the inhibitory effect of V. baillonii was further investigated using an in vitro hepatocyte NAFLD model. Fourteen active components were then selected from the 27 known compounds of V. baillonii. The targets of gene enrichment analysis were mainly distributed in the lipid catabolism-related signaling pathway. Network analysis revealed that five target genes of TNF, MAPK8, mTOR, NF-ĸB, and SREBP-1c were key nodes and played important roles in this process. Organ localization analysis indicated that one of the core target site of V. baillonii was liver tissue. The results of the in vitro study revealed that WVBF can alleviate the inflammatory response and lipid accumulation in LO2 hepatocytes by inhibiting oxidative stress and the adipocytokine signaling pathway. Genes and proteins related to the lipid synthesis, such as SREBP-1C, acetyl-CoA carboxylase (ACC), and fatty acid synthase (FASN), were significantly decreased, and PPARα expression is significantly increased with WVBF administration. In conclusion, V. baillonii may regulate local lipid metabolism and attenuate oxidative stress and inflammatory factors through the PPARα/SREBP-1c signaling pathway. The present study also indicates that multiple components of V. baillonii regulate multiple targets and pathways in NAFLD. The findings highlight the potential of V. baillonii as a promising treatment strategy for nonalcoholic fatty liver injury.

Palmitic Acid Promotes Virus Replication in Fish Cell by Modulating Autophagy Flux and TBK1-IRF3/7 Pathway

Palmitic acid is the most common saturated fatty acid in animals, plants, and microorganisms. Studies highlighted that palmitic acid plays a significant role in diverse cellular processes and viral infections. Accumulation of palmitic acid was observed in fish cells (grouper spleen, GS) infected with Singapore grouper iridovirus (SGIV). The fluctuated content levels after viral infection suggested that palmitic acid was functional in virus-cell interactions. In order to investigate the roles of palmitic acid in SGIV infection, the effects of palmitic acid on SGIV induced cytopathic effect, expression levels of viral genes, viral proteins, as well as virus production were evaluated. The infection and replication of SGIV were increased after exogenous addition of palmitic acid but suppressed after knockdown of fatty acid synthase (FASN), of which the primary function was to catalyze palmitate synthesis. Besides, the promotion of virus replication was associated with the down-regulating of interferon-related molecules, and the reduction of IFN1 and ISRE promotor activities by palmitic acid. We also discovered that palmitic acid restricted TBK1, but not MDA5-induced interferon immune responses. On the other hand, palmitic acid decreased autophagy flux in GS cells via suppressing autophagic degradation, and subsequently enhanced viral replication. Together, our findings indicate that palmitic acid is not only a negative regulator of TBK1-IRF3/7 pathway, but also a suppressor of autophagic flux. Finally, palmitic acid promotes the replication of SGIV in fish cells.

Different Phenolic Extracts of Oil Palm Fruits and Caffeic Acid Prevent Palmitic Acid-Induced Lipotoxicity in HepG2 Cells via Improving Mitochondrial Function

Oil palm (Elaeis guineensis Jacq.) fruits are rich in antioxidative phenolic compounds, which exert various health improving effects. This study aimed to comparatively study the protective effects of different phenolic fractions from the fruits treated with or without ultrahigh pressure (UHP) and their most abundant phenolic substance, caffeic acid, against the palmitic acid-induced lipotoxicity in HepG2 cells and to clarify the potential mechanisms. Results showed that the TG accumulation, intracellular reactive oxygen species content, cell apoptosis, and mitochondrial membrane potential depolarization were relieved by the administration of those phenolic fractions and caffeic acid. The protection of insoluble-bound (IB) phenolic fraction was the best, and UHP treatment significantly enhanced its protective effect on lipotoxicity. The lipotoxicity preventive effect may be achieved by alleviating intracellular oxidative stress, downregulating the expression of P-P38, COX-2, and iNOS to relieve inflammation, and downregulating Bax and cytochrome C and upregulating Bcl-2 to suppress the mitochondrial-mediated apoptosis. Therefore, the oil palm fruits phenolic fractions, especially the IB phenolic fraction, might be utilized as dietary antioxidants to relieve the adverse effects of a high-fat diet on the body, and UHP treatment is a potential method to increase this bioactivity.

A Candidate Drug for Nonalcoholic Fatty Liver Disease: A Review of Pharmacological Activities of Polygoni Multiflori Radix

Nonalcoholic fatty liver disease, a type of metabolic syndrome, continues to rise globally. Currently, there is no approved drug for its treatment. Improving lifestyle and exercise can alleviate symptoms, but patients' compliance is poor. More and more studies have shown the potential of Polygoni Multiflori Radix (PMR) in the treatment of NAFLD and metabolic syndrome. Therefore, this paper reviews the pharmacological effects of PMR and its main chemical components (tetrahydroxystilbene glucoside, emodin, and resveratrol) on NAFLD. PMR can inhibit the production of fatty acids and promote the decomposition of triglycerides, reduce inflammation, and inhibit the occurrence of liver fibrosis. At the same time, it maintains an oxidation equilibrium status in the body, to achieve the therapeutic purpose of NAFLD and metabolic syndrome. Although more standardized studies and clinical trials are needed to confirm its efficacy, PMR may be a potential drug for the treatment of NAFLD and its complications. However, the occurrence of adverse reactions of PMR has affected its extensive clinical application. Therefore, it is necessary to further study its toxicity mechanism, enhance efficacy and control toxicity, and even reduce toxicity, which will contribute to the safe clinical use of PMR.

Stability of natural polyphenol fisetin in eye drops Stability of fisetin in eye drops

Fisetin is a polyphenolic compound with anti-inflammatory and antioxidant properties. Inflammation and reactive oxygen species play a major role in the pathophysiology of the dry eye syndrome (DES). Patients with DES undergo symptomatic treatment using eye drops known as artificial tears. Addition of fisetin into the eye drops could result in a better recovery of the eye surface. This experimental study examines the stability of fisetin in selected eye drops (Arufil, Hypromelóza-P, Ocutein, Refresh). Absorption spectra of fisetin were measured in selected eye drops, dimethylsulphoxide (DMSO), deionized water and normal saline solution (NSS) during a period of four weeks. The fisetin absorption maximum was placed at 350 – 390 nm depending on the solvent. Good stability of fisetin solutions were observed in DMSO and deionized water. The highest stability of fisetin in selected eye drops was observed in Hypromelóza-P. Irreversible fisetin structural changes were detected in Arufil, Ocutein, Refresh and NSS. For further clinical evaluation, fisetin solution in Hypromelóza-P could be examined.

Dietary Polyphenols Protect Against Oleic Acid-Induced Steatosis in an in Vitro Model of NAFLD by Modulating Lipid Metabolism and Improving Mitochondrial Function

In this study, we aimed to determine the relative effectiveness of common dietary polyphenols or the isoquinoline alkaloid berberine in protecting against molecular mechanisms underlying non-alcoholic fatty liver disease (NAFLD) involving changes to cellular lipid metabolism and bioenergetics. In a model of steatosis using HepG2 hepatocytes, exposure of the cells to 1.5 mM oleic acid (OA) for 24 h caused steatosis and distorted cell morphology, induced the expression of mRNA for enzymes that are involved in lipogenesis and fatty acid oxidation (FAS and CPT1A), and impaired indices of aerobic energy metabolism (PPARγ mRNA expression, mitochondrial membrane potential (MMP), and galactose-supported ATP production). Co-treatment with 10 µM of selected polyphenols all strongly protected against the steatosis and changes in cell morphology. All polyphenols, except cyanidin, inhibited the effects on FAS and PPARγ and further increased CPT1A1 expression, suggesting a shift toward increased β-oxidation. Resveratrol, quercetin, catechin, and cyanidin, however not kuromanin or berberine, ameliorated the decreases in MMP and galactose-derived ATP. Berberine was unique in worsening the decrease in galactose-derived ATP. In further investigations of the mechanisms involved, resveratrol, catechin, and berberine increased SIRT1 enzyme activity and p-AMPKα^Thr172 protein, which are involved in mitochondrial biogenesis. In conclusion, selected polyphenols all protected against steatosis with similar effectiveness, however through different mechanisms that increased aerobic lipid metabolism and mitochondrial function.

Preventive Effect of YGDEY from Tilapia Fish Skin Gelatin Hydrolysates against Alcohol-Induced Damage in HepG2 Cells through ROS-Mediated Signaling Pathways

According to a previous study, YGDEY from tilapia fish skin gelatin hydrolysates has strong free radical scavenging activity. In the present study, the protective effect of YGDEY against oxidative stress induced by ethanol in HepG2 cells was investigated. First, cells were incubated with YGDEY (10, 20, 50, and 100 μM) to assess cytotoxicity, and there was no significant change in cell viability. Next, it was established that YGDEY decreased the production of reactive oxygen species (ROS). Western blot results indicated that YGDEY increased the levels of superoxide dismutase (SOD) and glutathione (GSH) and decreased the expression of gamma-glutamyltransferase (GGT) in HepG2 cells. It was then revealed that YGDEY markedly reduced the expressions of bax and cleaved-caspase-3 (c-caspase-3); inhibited phosphorylation of Akt, IκB-α, p65, and p38; and increased the level of bcl-2. Moreover, the comet assay showed that YGDEY effectively decreased the amount of ethanol-induced DNA damage. Thus, YGDEY protected HepG2 cells from alcohol-induced injury by inhibiting oxidative stress, and this may be associated with the Akt/nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signal transduction pathways. These results demonstrate that YGDEY from tilapia fish skin gelatin hydrolysates protects HepG2 cells from oxidative stress, making it a potential functional food ingredient.

Effect of Resveratrol on Blood Lipid Levels in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis

OBJECTIVE

Few studies have considered the effect of resveratrol on blood lipid levels, and the results of these studies are inconsistent. In this study, the first meta-analysis on the effect of resveratrol on blood lipid levels in patients with type 2 diabetes was conducted.

METHODS

This study used keywords such as type 2 diabetes, total cholesterol, triglyceride (TG), high-density lipoprotein, low-density lipoprotein, and resveratrol and their abbreviations, free words, and related words to search PubMed, Cochrane Library, and Embase. The Cochrane risk of bias tool was used to evaluate the risk of bias, and Review Manager 5.3 and Stata 13.0 were used for data merging and statistical analysis.

RESULTS

Ten randomized controlled trials involving a total of 363 patients with type 2 diabetes were included in the analysis. The results show that longer resveratrol intervention time (≥6 months) can reduce TG levels. But resveratrol increased total cholesterol in patients within obesity range. In type 2 diabetes patients with obesity and in those who took lipid-lowering drugs, resveratrol increased low-density lipoprotein levels.

CONCLUSIONS

Resveratrol can improve TG in patients with type 2 diabetes.

Cichoric Acid Prevents Free-Fatty-Acid-Induced Lipid Metabolism Disorders via Regulating Bmal1 in HepG2 Cells

Cichoric acid (CA), a polyphenol component from Echinacea purpurea, exhibits preventive effects on liver lipid-metabolism disorders in obesity. This research aimed to determine the role of circadian rhythm signaling during the process of CA-attenuated lipid accumulation in hepatocytes. In the current study, CA treatments improved cell morphology changes and hepatic lipid levels, which were triggered by free fatty acids (2:1, oleate: palmitate) in a dose-dependent way. Besides, CA (200 μM) regulated the circadian rhythm expressions of clock genes and the relatively shallow daily oscillations. Moreover, silencing Bmal1 significantly blocked the p-Akt/Akt pathway to 80.1% ± 1.5% and the p-GSK3β/GSK3β pathway to 64.7% ± 2.8% ( p < 0.05). Furthermore, silencing Bmal1 elevated the expressions of FAS and ACC to 122.4% ± 5.6% and 114.9% ± 1.7% in protein levels ( p < 0.05) and to 166.5% ± 18.5% and 131.4% ± 5.5% in mRNA levels ( p < 0.05). Therefore, our results demonstrated that CA has a Bmal1 resistance to lipid accumulation by enhancing the Akt/GSK3β signaling pathways and modulating the downstream expressions related to lipid metabolism, which indicated that CA might be useful as a natural and promising nonalcoholic fatty liver diseases (NAFLD) modulator.