Metformin Alleviates Hepatic Steatosis and Insulin Resistance in a Mouse Model of High-Fat Diet-Induced Nonalcoholic Fatty Liver Disease by Promoting Transcription Factor EB-Dependent Autophagy

Ginsenoside CK and retinol on UVA-induced photoaging exert the synergistic effect through antioxidant and antiapoptotic mechanisms

Retinol and retinoids can effectively intervene skin aging process, but usually induce skin intolerance. In this study, we aimed to determine the synergistic anti-aging effects of retinol and two retinol derivatives-hydroxypinacolone retinoate (HPR) and retinol palmitate (VAPA) combined with ginsenoside CK in terms of preventing and treating the UVA radiation-induced skin aging. We found that the combination formulation of retinol and ginsenoside CK alleviated the inhibition of photoaging proliferation of HaCaT cells caused by UVA, and reduced the proportion of senescence. Additionally, the combination of retinol, HPR, VAPA with ginsenoside CK significantly down-regulated the expression of P53 and P21, up-regulated P63 in UVA irradiated cells, and had potential anti-apoptotic activity. Ginsenoside CK intervention also inhibited the degradation of collagen and elastin by reducing the expression of matrix metalloproteinases, and significantly alleviated oxidative stress. Further transcriptomic and molecular docking studies suggested that ginsenoside CK may play an anti-photoaging role by binding to the active pocket of AKR1C1 and AKR1C2 proteins. Zebrafish experiment showed that retinol combined with ginsenoside CK had the effect of reducing skin toxicity. In conclusion, our results show that retinol, HPR and VAPA combined with ginsenoside CK have good anti-aging and irritation-reducing effects in vitro and in vivo.

Investigating the Effects of Gossypetin on Liver Health in Diet-Induced Pre-Diabetic Male Sprague Dawley Rats

The rising prevalence of non-alcoholic fatty liver disease among patients with type 2 diabetes mellitus has emerged as a global health challenge. Gossypetin (GTIN) is a natural flavonoid which has recently demonstrated antihyperglycaemic, antioxidant, and anti-inflammatory effects. Despite these findings, no studies have investigated its effects on liver health in the pre-diabetic state. Hence, this study aimed to investigate the effects of GTIN on liver health in diet-induced pre-diabetic male rats in the presence and absence of dietary intervention and to compare these effects with those of metformin (MET). Following 20 weeks of pre-diabetes induction, the animals were divided into six groups (n = 6) as follows: non-pre-diabetic (NPD) control, pre-diabetic (PD) control, and PD groups treated with GTIN (15 mg/kg body weight (bw)) or metformin (500 mg/kg bw) on either a normal diet or a high-fat, high-carbohydrate diet for 12 weeks. The results showed that the PD group had significantly higher liver triglycerides (TAG), liver weights, sterol regulatory binding element regulatory protein-1c (SREBP-1c), malondialdehyde (MDA) levels, and liver injury enzyme levels, along with decreased liver superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, and plasma bilirubin levels in comparison to NPD. Histologically, there was an increased lipid droplet accumulation and structural disarray in the PD group. GTIN treatment significantly reduced liver TAGs, liver weights, and plasma SREBP-1c levels, as well as improved liver SOD and GPx activity while decreasing liver MDA levels and liver injury enzymes in comparison to the PD control. Notably, GTIN treatment increased plasma bilirubin levels. Liver histology in the GTIN-treated groups revealed decreased lipid droplet accumulation and improved tissue integrity. Similar results were observed for the liver parameters in the MET-treated groups. The findings of this study may suggest that GTIN and MET exhibit therapeutic effects on liver health in diet-induced pre-diabetes in both the presence and absence of diet intervention. Dietary intervention may confer beneficial effects on liver health, with the most favorable therapeutic outcomes observed through a combination of treatment with dietary intervention. Additionally, GTIN may exhibit greater hepatoprotective effects than MET in rats without dietary intervention.

L-carnitine attenuates autophagic flux, apoptosis, and necroptosis in rats with dexamethasone-induced non-alcoholic steatohepatitis

BACKGROUND

UpToDate, no drugs have been approved to treat nonalcoholic steatohepatitis, the advanced stage of the most prevalent liver disease, non-alcoholic fatty liver disease. The present study was conducted to explore the potential influences of L-carnitine on the pathomechanisms of hepatic injury that mediate progression to non-alcoholic steatohepatitis in dexamethasone-toxified rats.

METHODS

Male Wistar rats were allocated as follows: dexamethasone group, rats received dexamethasone (8 mg/kg/day, intraperitoneally) for 6 days; DEXA-LCAR300, DEXA-LCAR500, and DEXA-MET groups, rats administered L-carnitine (300 or 500 mg/kg/day, IP) or metformin (500 mg/kg/day, orally) one week prior to dexamethasone injection (8 mg/kg/day, IP) and other six days alongside dexamethasone administration. Two groups of age-matched normal rats received either the drug vehicle (the control group) or the higher dose of L-carnitine (the drug-control group). At the end of the experiment, sets of biochemical, histological, and immunohistochemical examinations were performed.

RESULTS

L-carnitine (mainly at the dose of 500 mg/kg/day) markedly abolished dexamethasone-induced alterations in glucose tolerance, hepatic histological features, and serum parameters of hepatic function and lipid profile. Moreover, it significantly ameliorated dexamethasone-induced elevations of hepatic oxidative stress, SREBP-1 and p-MLKL protein levels, and nuclear FOXO1, LC3, P62, and caspase-3 immunohistochemical expression. Furthermore, it markedly diminished dexamethasone-induced suppression of hepatic Akt phosphorylation and Bcl2 immunohistochemical expression. The effects of L-carnitine (500 mg/kg/day) were comparable to those of metformin in most assessments and better than its corresponding lower dose.

CONCLUSION

These findings introduce L-carnitine as a potential protective drug that may mitigate the rate of disease progression in non-alcoholic fatty liver disease patients with early stages or those at the highest risks.

Metformin Protects Against Acute Kidney Injury Induced by Lipopolysaccharide via Up-Regulating the MCPIP1/SIRT1 Pathway

In the present study, we aimed to explore the effect and underlying mechanism of metformin on lipopolysaccharide (LPS)-induced acute kidney injury (AKI). A total of 24 BALB/C mice were randomly divided into four groups: control group, LPS group and metformin group (50 or 100 mg/kg). The histological changes and cell apoptosis in kidney tissues were detected by hematoxylin-eosin staining and terminal-deoxynucleotidyl transferase-mediated nick end labeling assay, respectively. Enzyme-linked immunosorbent assay was applied to determine serum levels of blood urea nitrogen (BUN), kidney injury molecule-1 (Kim-1), creatinine (Cre), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). Western blotting analysis were carried out to confirm the expressions of monocyte chemotactic protein-inducible protein 1 (MCPIP1), silent information regulator sirtuin 1 (SIRT1), and NF-κB p65 (acetyl K310). Compared with the control group, the mice in LPS group had glomerular capillary dilatation, renal interstitial edema, tubular cell damage and apoptosis. The serum levels of BUN, KIM-1, Cre, TNF-α, and IL-1β in LPS group were significantly higher than those in control group. Moreover, LPS also elevated the expressions of MCPIP1 and NF-κB p65 (acetyl K310) but decreased the expression of SIRT1 in kidney tissues. However, metformin distinctly decreased LPS-induced renal dysfunction, the serum levels of BUN, KIM-1, Cre, TNF-α, and IL-1β. In addition, metformin markedly increased the expressions of MCPIP1 and SIRT1 but decreased the expression of NF-κB p65 (acetyl K310) in kidney tissues. Metformin prevented LPS-induced AKI by up-regulating the MCPIP1/SIRT1 signaling pathway and subsequently inhibiting NF-κB-mediated inflammation response.

Empagliflozin add-on therapy is superior to metformin monotherapy in diabetic patients with NAFLD: An open-label, single-center, pilot clinical trial

Background

The prevalence of non-alcoholic fatty liver disease (NAFLD), which is characterized by hepatic steatosis, inflammation, and advanced fibrosis, is high among type-2 diabetes mellitus (T2DM) patients. Empagliflozin (EMPA), a sodium-glucose cotransporter-2 inhibitor, has been well established to improve glycemic status in T2DM. However, evidence of the desirable effects of EMPA, when added to the standard treatment in diabetics with coexisting NAFLD, has yet to be determined.

Objective

The main objective of the current study is to explore the benefits of EMPA on hepatic fat content in patients with T2DM and NAFLD, who received metformin (MET) monotherapy.

Methods

In this open-label clinical trial study, 60 patients with T2DM and NAFLD were assigned to either the MET + EMPA or MET group in an up-titrated manner for 24 weeks. Anthropometric characteristics, blood glucose indices, lipid profile, liver enzymes, and steatosis grades were measured at baseline and 24 weeks after the intervention.

Results

The results showed that in patients with a mean age of 53.26 ± 7.64 who received MET+ EMPA, all the parameters had a greater decrease than the MET group. In addition, the reduction of FBS, BS, HbA1C, TG, and ALT had a statistically significant difference between the two groups after 24 weeks follow-up (p < 0.05). Notably, in the MET+ EMPA group, there was a substantial improvement in steatosis grades based on the fibroscan and ultrasound modality results.

Conclusion

The EMPA add-on therapeutic schedule in uncontrolled T2DM patients with NAFLD significantly ameliorated steatosis stages, liver function, anthropometric features, and biochemical parameters.

Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?

Metformin is a widely employed drug in type 2 diabetes. In addition to warranting good short- and long-term glycemic control, metformin displays many intriguing properties as protection against cardiovascular and neurodegenerative diseases, anti-tumorigenic and longevity promotion. In addition to being a low-cost drug, metformin is generally well tolerated. However, despite the enthusiastic drive to aliment these novel studies, many contradictory results suggest the importance of better elucidating the complexity of metformin action in different tissues/cells to establish its possible employment in neurodegenerative diseases. This review summarises recent data identifying lysosomal-dependent processes and lysosomal targets, such as endosomal Na+/H+ exchangers, presenilin enhancer 2 (PEN2), the lysosomal pathway leading to AMP-activated protein kinase (AMPK) activation, and the transcription factor EB (TFEB), modulated by metformin. Lysosomal dysfunctions resulting in autophagic and lysosomal acidification and biogenesis impairment appear to be hallmarks of many inherited and acquired neurodegenerative diseases. Lysosomes are not yet seen as a sort of cellular dump but are crucial in determining key signalling paths and processes involved in the clearance of aggregated proteins. Thus, the possibility of pharmacologically modulating them deserves great interest. Despite the potentiality of metformin in this context, many additional important issues, such as dosing, should be addressed in the future.

Role of β-cell autophagy in β-cell physiology and the development of diabetes

Elucidating the molecular mechanism of autophagy was a landmark in understanding not only the physiology of cells and tissues, but also the pathogenesis of diverse diseases, including diabetes and metabolic disorders. Autophagy of pancreatic β-cells plays a pivotal role in the maintenance of the mass, structure and function of β-cells, whose dysregulation can lead to abnormal metabolic profiles or diabetes. Modulators of autophagy are being developed to improve metabolic profile and β-cell function through the removal of harmful materials and rejuvenation of organelles, such as mitochondria and endoplasmic reticulum. Among the known antidiabetic drugs, glucagon-like peptide-1 receptor agonists enhance the autophagic activity of β-cells, which might contribute to the profound effects of glucagon-like peptide-1 receptor agonists on systemic metabolism. In this review, the results from studies on the role of autophagy in β-cells and their implication in the development of diabetes are discussed. In addition to non-selective (macro)autophagy, the role and mechanisms of selective autophagy and other minor forms of autophagy that might occur in β-cells are discussed. As β-cell failure is the ultimate cause of diabetes and unresponsiveness to conventional therapy, modulation of β-cell autophagy might represent a future antidiabetic treatment approach, particularly in patients who are not well managed with current antidiabetic therapy.

Cell Death in Liver Disease and Liver Surgery

Cell death is crucial for maintaining tissue balance and responding to diseases. However, under pathological conditions, the surge in dying cells results in an overwhelming presence of cell debris and the release of danger signals. In the liver, this gives rise to hepatic inflammation and hepatocellular cell death, which are key factors in various liver diseases caused by viruses, toxins, metabolic issues, or autoimmune factors. Both clinical and in vivo studies strongly affirm that hepatocyte death serves as a catalyst in the progression of liver disease. This advancement is characterized by successive stages of inflammation, fibrosis, and cirrhosis, culminating in a higher risk of tumor development. In this review, we explore pivotal forms of cell death, including apoptosis, pyroptosis, and necroptosis, examining their roles in both acute and chronic liver conditions, including liver cancer. Furthermore, we discuss the significance of cell death in liver surgery and ischemia-reperfusion injury. Our objective is to illuminate the molecular mechanisms governing cell death in liver diseases, as this understanding is crucial for identifying therapeutic opportunities aimed at modulating cell death pathways.

Dysfunction of autophagy in high-fat diet-induced non-alcoholic fatty liver disease

ABBREVIATIONS

ACOX1: acyl-CoA oxidase 1; ADH5: alcohol dehydrogenase 5 (class III), chi polypeptide; ADIPOQ: adiponectin, C1Q and collagen domain containing; ATG: autophagy related; BECN1: beclin 1; CRTC2: CREB regulated transcription coactivator 2; ER: endoplasmic reticulum; F2RL1: F2R like trypsin receptor 1; FA: fatty acid; FOXO1: forkhead box O1; GLP1R: glucagon like peptide 1 receptor; GRK2: G protein-coupled receptor kinase 2; GTPase: guanosine triphosphatase; HFD: high-fat diet; HSCs: hepatic stellate cells; HTRA2: HtrA serine peptidase 2; IRGM: immunity related GTPase M; KD: knockdown; KDM6B: lysine demethylase 6B; KO: knockout; LAMP2: lysosomal associated membrane protein 2; LAP: LC3-associated phagocytosis; LDs: lipid droplets; Li KO: liver-specific knockout; LSECs: liver sinusoidal endothelial cells; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAP3K5: mitogen-activated protein kinase kinase kinase 5; MED1: mediator complex subunit 1; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin complex 1; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; NFE2L2: NFE2 like bZIP transcription factor 2; NOS3: nitric oxide synthase 3; NR1H3: nuclear receptor subfamily 1 group H member 3; OA: oleic acid; OE: overexpression; OSBPL8: oxysterol binding protein like 8; PA: palmitic acid; RUBCNL: rubicon like autophagy enhancer; PLIN2: perilipin 2; PLIN3: perilipin 3; PPARA: peroxisome proliferator activated receptor alpha; PRKAA2/AMPK: protein kinase AMP-activated catalytic subunit alpha 2; RAB: member RAS oncogene family; RPTOR: regulatory associated protein of MTOR complex 1; SCD: stearoyl-CoA desaturase; SIRT1: sirtuin 1; SIRT3: sirtuin 3; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SQSTM1/p62: sequestosome 1; SREBF1: sterol regulatory element binding transcription factor 1;SREBF2: sterol regulatory element binding transcription factor 2; STING1: stimulator of interferon response cGAMP interactor 1; STX17: syntaxin 17; TAGs: triacylglycerols; TFEB: transcription factor EB; TP53/p53: tumor protein p53; ULK1: unc-51 like autophagy activating kinase 1; VMP1: vacuole membrane protein 1.

Organelle stress and alterations in interorganelle crosstalk during liver fibrosis

The synchronous functioning and quality control of organelles ensure cell survival and function and are essential for maintaining homeostasis. Prolonged exposure to stressors (viruses, bacteria, parasitic infections, alcohol, drugs) or genetic mutations often disrupt the functional integrity of organelles which plays a critical role in the initiation and progression of several diseases including chronic liver diseases. One of the most important pathologic consequences of chronic liver diseases is liver fibrosis, characterized by tissue scarring due to the progressive accumulation of extracellular matrix components. Left untreated, fibrosis may advance to life-threatening complications such as cirrhosis, hepatic decompensation, and HCC, which collectively accounts for ∼1 million deaths per year worldwide. Owing to the lack of treatment options that can regress or reverse cirrhosis, liver transplantation is currently the only available treatment for end-stage liver disease. However, the limited supply of usable donor organs, adverse effects of lifelong immunosuppressive regimes, and financial considerations pose major challenges and limit its application. Hence, effective therapeutic strategies are urgently needed. An improved understanding of the organelle-level regulation of fibrosis can help devise effective antifibrotic therapies focused on reducing organelle stress, limiting organelle damage, improving interorganelle crosstalk, and restoring organelle homeostasis; and could be a potential clinical option to avoid transplantation. This review provides a timely update on the recent findings and mechanisms covering organelle-specific dysfunctions in liver fibrosis, highlights how correction of organelle functions opens new treatment avenues and discusses the potential challenges to clinical application.

Autophagy and diabetes

The current literature findings on autophagy’s beneficial and detrimental roles in diabetes mellitus (DM) and diabetes-related comorbidities were reviewed. The effects of oral hypoglycaemic medicines and autophagy in DM. Autophagy plays an important function in cellular homeostasis by promoting cell survival or initiating cell death in physiological settings was also assessed. Although autophagy protects insulin-target tissues, organelle failure caused by autophagy malfunction influences DM and other metabolic diseases. Endoplasmic reticulum and oxidative stress enhance autophagy levels, making it easier to regulate stress-induced intracellular changes. Evidence suggests that autophagy-caused cell death can occur when autophagy is overstimulated and constitutively activated, which might prevent or develop DM. Even though the precise role of autophagy in DM complications is uncertain, deregulation of the autophagic machinery is strongly linked to beta cell destruction and the aetiology of DM. Thus, improving autophagy dysfunction is a possible therapeutic objective in treating DM and other metabolic disorders.

The potential effect of metformin on fibroblast growth factor 21 in type 2 diabetes mellitus (T2DM)

Fibroblast growth factor 21 (FGF21) is a peptide hormone mainly synthesized and released from the liver. FGF21 acts on FGF21 receptors (FGFRs) and β-Klotho, which is a transmembrane co-receptor. In type 2 diabetes mellitus (T2DM), inflammatory disorders stimulate the release of FGF21 to overcome insulin resistance (IR). FGF21 improves insulin sensitivity and glucose homeostasis. Metformin which is used in the management of T2DM may increase FGF21 expression. Accordingly, the objective of this review was to clarify the metformin effect on FGF21 in T2DM. FGF21 level and expression of FGF2Rs are dysregulated in T2DM due to the development of FGF21 resistance. Metformin stimulates the hepatic expression of FGF21/FGF2Rs by different signaling pathways. Besides, metformin improves the expression of β-Klotho which improves FGF21 sensitivity. In conclusion, metformin advances FGF21 signaling and decreases FGF21 resistance in T2DM, and this might be an innovative mechanism for metformin in the enhancement of glucose homeostasis and metabolic disorders in T2DM patients.

Mechanistic insights of soluble uric acid-induced insulin resistance: Insulin signaling and beyond

Hyperuricemia is a metabolic disease caused by purine nucleotide metabolism disorder. The prevalence of hyperuricemia is increasing worldwide, with a growing trend in the younger populations. Although numerous studies have indicated that hyperuricemia may be an independent risk factor for insulin resistance, the causal relationship between the two is controversial. There are few reviews, however, focusing on the relationship between uric acid (UA) and insulin resistance from experimental studies. In this review, we summarized the experimental models related to soluble UA-induced insulin resistance in pancreas and peripheral tissues, including skeletal muscles, adipose tissue, liver, heart/cardiomyocytes, vascular endothelial cells and macrophages. In addition, we summarized the research advances about the key mechanism of UA-induced insulin resistance. Moreover, we attempt to identify novel targets for the treatment of hyperuricemia-related insulin resistance. Lastly, we hope that the present review will encourage further researches to solve the chicken-and-egg dilemma between UA and insulin resistance, and provide strategies for the pathogenesis and treatment of hyperuricemia related metabolic diseases.

Fagopyrum dibotrys extract alleviates hepatic steatosis and insulin resistance, and alters autophagy and gut microbiota diversity in mouse models of high-fat diet-induced non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a major global health concern with increasing prevalence, with a lack of currently available effective treatment options; thus, the investigation of novel therapeutic approaches is necessary. The study aimed to investigate the outcomes and mechanisms of action of Fagopyrum dibotrys extract (FDE) in a high-fat diet (HFD)-induced mouse model of obesity. The findings showed that FDE supplementation attenuated glucose tolerance, insulin resistance (IR), hepatic steatosis, and abnormal lipid metabolism. In addition, FDE also promoted autophagic activity and inhibited the phosphorylation of transcription factor EB in HFD-fed mice. Furthermore, gut microbiota characterization via 16S rRNA sequencing revealed that the supplementation of FDE increased Bacteroidetes and Verrucomicrobia populations while decreased Firmicutes, thus modifying the gut microbiome. FDE also increased the relative abundance of Akkermansia. Our findings suggest that FDE may protect against HFD-induced NAFLD by activating autophagy and alleviating dysbiosis in the gut microbiome. FDE may be beneficial as a nutraceutical treatment for NAFLD.

Targeting the lysosome: Mechanisms and treatments for nonalcoholic fatty liver disease

The multiple functions of the lysosome, including degradation, nutrient sensing, signaling, and gene regulation, enable the lysosome to regulate lipid metabolism at different levels. In this review, I summarize the recent studies on lysosomal regulation of lipid metabolism and the alterations of the lysosome functions in the livers affected by nonalcoholic fatty liver disease (NAFLD). NAFLD is a highly prevalent lipid metabolic disorder. The progression of NAFLD leads to nonalcoholic steatohepatitis (NASH) and other severe liver diseases, and thus the prevention and treatments of NAFLD progression are critically needed. Targeting the lysosome is a promising strategy. I also discuss the current manipulations of the lysosome functions in the preclinical studies of NAFLD and propose my perspectives on potential future directions.

Molecular mechanisms of metabolic associated fatty liver disease (MAFLD): functional analysis of lipid metabolism pathways

The metabolic-associated fatty liver disease (MAFLD) is a condition of fat accumulation in the liver in combination with metabolic dysfunction in the form of overweight or obesity and insulin resistance. It is also associated with an increased cardiovascular disease risk, including hypertension and atherosclerosis. Hepatic lipid metabolism is regulated by a combination of the uptake and export of fatty acids, de novo lipogenesis, and fat utilization by β-oxidation. When the balance between these pathways is altered, hepatic lipid accumulation commences, and long-term activation of inflammatory and fibrotic pathways can progress to worsen the liver disease. This review discusses the details of the molecular mechanisms regulating hepatic lipids and the emerging therapies targeting these pathways as potential future treatments for MAFLD.

Advances in metformin for the treatment of non-alcoholic fatty liver disease in children

INTRODUCTION

The increased economic and social burdens for NAFLD worldwide make treating such a disease a significant public health issue. Metformin, a kind of insulin sensitizer generally used to treat type 2 diabetes, has been recently found to have efficacy on children's NAFLD in various areas such as glucolipid metabolism, intestinal bacterial metabolism, oxidative stress, and anti-inflammatory response. This article aims to provide an overview of the possible mechanisms of NAFLD in children and the potential therapeutic application of metformin.

AREAS COVERED

The Cochrane Library, PubMed, Scopus, and EMBASE database was systematically searched on 12 April 2022, using the keywords metformin; non-alcoholic fatty liver disease; and children to identify similar studies. An additional search for recently published research was performed in June 2020.

EXPERT OPINION

Although metformin has been proved to have an excellent therapeutic effect on children's NAFLD; we can still explore its potential impacts and mechanisms from different angles, such as combined medication. At the same time, we should also pay attention to its side effects.

Research progress on the relationship between autophagy and chronic complications of diabetes

Diabetes is a common metabolic disease whose hyperglycemic state can induce diverse complications and even threaten human health and life security. Currently, the treatment of diabetes is restricted to drugs that regulate blood glucose and have certain accompanying side effects. Autophagy, a research hotspot, has been proven to be involved in the occurrence and progression of the chronic complications of diabetes. Autophagy, as an essential organismal defense mechanism, refers to the wrapping of cytoplasmic proteins, broken organelles or pathogens by vesicles, which are then degraded by lysosomes to maintain the stability of the intracellular environment. Here, we review the relevant aspects of autophagy and the molecular mechanisms of autophagy in diabetic chronic complications, and further analyze the impact of improving autophagy on diabetic chronic complications, which will contribute to a new direction for further prevention and treatment of diabetic chronic complications.

Berberrubine, a Main Metabolite of Berberine, Alleviates Non-Alcoholic Fatty Liver Disease via Modulating Glucose and Lipid Metabolism and Restoring Gut Microbiota

Non-alcoholic fatty liver disease (NAFLD) is a major public health problem in many countries. Berberine (BBR) is an effective therapeutic agent in alleviating NAFLD. Berberrubine (BRB) is one of the main active metabolites of BBR, which shows significant anti-obesity and antihypoglycemic effects. However, whether BRB is responsible for the in vivo therapeutic effect and the underlying mechanism of BRB on NAFLD have not been elucidated. In this study, the ability of BRB to ameliorate NAFLD, together with its molecular mechanism, was investigated. The results showed that BRB treatments could significantly improve hepatic steatosis and insulin resistance in high-fat diet (HFD)–fed mice and oleic acid (OA)–treated HepG2 cells. Meanwhile, BBR and BRB treatment similarly prevented lipid accumulation by regulating the protein expression of ATGL, GK, PPARα, CPT-1, ACC1, FAS, and CD36. In addition, compared with BBR, BRB could maintain glucose homeostasis via GLUT2, GSK3β, and G6Pase in HFD-fed mice. Furthermore, the components of the gut microbiota in mice were analyzed by 16S rRNA gene sequencing. BBR and BRB treatment could greatly modify the structure and composition of gut microbiota. At the genus level, BBR and BRB treatment decreased Lactobacillus and Romboutsia, while BBR increased beneficial bacteria, such as Akkermansia and Bacteroides, and BRB increased beneficial bacteria, such as Ileibacterium and Mucispirillum. Altogether, both BRB and BBR were active in alleviating NAFLD in vivo and BRB might be used as a functional material to treat NAFLD clinically.

Role of TFEB in Autophagy and the Pathogenesis of Liver Diseases

The transcription factor EB (TFEB) is a master regulator of lysosomal function and autophagy. Mechanistic target of rapamycin (mTOR)-mediated phosphorylation on TFEB is known to regulate TFEB subcellular localization and activity at the lysosomal surface. Recent studies have shown that TFEB also plays a critical role in physiological processes such as lipid metabolism, and dysfunction of TFEB has been observed in the pathogenesis of several diseases. Owing to its ability to improve disease status in murine models, TFEB has attracted attention as a therapeutic target for diseases. In this review, we will present the regulation of TFEB and its role in the pathogenesis of liver diseases, particularly non-alcoholic fatty liver disease (NAFLD).

Atherosclerosis and Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a common disease defined by excess fat deposition in the liver. The course of NAFLD is not fully understood, however, some pathogenic mechanisms have been identified. Accumulation of fat in liver cells is associated with insulin resistance, central obesity, triglyceride accumulation in the liver and hepatic fatty acid metabolism dysregulation that cause steatosis. The other process leads to hepatocyte inflammation and necrosis, which leads to severe hepatic disease; non-alcoholic steatohepatitis. Many clinical studies have underlined the link between NAFLD and atherosclerosis. NAFLD may alter the balance lipid-glucose metabolism as well as increase the risk of hypertension and systemic inflammation. This results in a greater risk of vascular events. The present review considers the link between NAFLD and atherosclerosis.

The Beneficial Additive Effect of Silymarin in Metformin Therapy of Liver Steatosis in a Pre-Diabetic Model

The combination of plant-derived compounds with anti-diabetic agents to manage hepatic steatosis closely associated with diabetes mellitus may be a new therapeutic approach. Silymarin, a complex of bioactive substances extracted from Silybum marianum, evinces an antioxidative, anti-inflammatory, and hepatoprotective activity. In this study, we investigated whether metformin (300 mg/kg/day for four weeks) supplemented with micronized silymarin (600 mg/kg/day) would be effective in mitigating fatty liver disturbances in a pre-diabetic model with dyslipidemia. Compared with metformin monotherapy, the metformin-silymarin combination reduced the content of neutral lipids (TAGs) and lipotoxic intermediates (DAGs). Hepatic gene expression of enzymes and transcription factors involved in lipogenesis (Scd-1, Srebp1, Pparγ, and Nr1h) and fatty acid oxidation (Pparα) were positively affected, with hepatic lipid accumulation reducing as a result. Combination therapy also positively influenced arachidonic acid metabolism, including its metabolites (14,15-EET and 20-HETE), mitigating inflammation and oxidative stress. Changes in the gene expression of cytochrome P450 enzymes, particularly Cyp4A, can improve hepatic lipid metabolism and moderate inflammation. All these effects play a significant role in ameliorating insulin resistance, a principal background of liver steatosis closely linked to T2DM. The additive effect of silymarin in metformin therapy can mitigate fatty liver development in the pre-diabetic state and before the onset of diabetes.