Molecular basis of alcoholic fatty liver disease: From incidence to treatment

Liquid Chromatography/Tandem Mass Spectrometry Analysis of Sophora flavescens Aiton and Protective Effects against Alcohol-Induced Liver Injury and Oxidative Stress in Mice

In this study, we investigated the hepatoprotective effects of an ethanol extract of Sophora flavescens Aiton (ESF) on an alcohol-induced liver disease mouse model. Alcoholic liver disease (ALD) was caused by the administration of ethanol to male C57/BL6 mice who were given a Lieber-DeCarli liquid diet, including ethanol. The alcoholic fatty liver disease mice were orally administered ESF (100 and 200 mg/kg bw/day) or silymarin (50 mg/kg bw/day), which served as a positive control every day for 16 days. The findings suggest that ESF enhances hepatoprotective benefits by significantly decreasing serum levels of aspartate transaminase (AST) and alanine transaminase (ALT), markers for liver injury. Furthermore, ESF alleviated the accumulation of triglyceride (TG) and total cholesterol (TC), increased serum levels of superoxide dismutase (SOD) and glutathione (GSH), and improved serum alcohol dehydrogenase (ADH) activity in the alcoholic fatty liver disease mice model. Cells and organisms rely on the Kelch-like ECH-associated protein 1- Nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2) system as a critical defensive mechanism in response to oxidative stress. Therefore, Nrf2 plays an important role in ALD antioxidant responses, and its level is decreased by increased reactive oxidation stress (ROS) in the liver. ESF increased Nrf2, which was decreased in ethanol-damaged livers. Additionally, four polyphenol compounds were identified through a qualitative analysis of the ESF using LC-MS/MS. This study confirmed ESF's antioxidative and hangover-elimination effects and suggested the possibility of using Sophora flavescens Aiton (SF) to treat ALD.

The Role of Oxidative Stress in Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Preclinical Studies

Alcoholic Fatty Liver Disease (AFLD) is characterized by the accumulation of lipids in liver cells owing to the metabolism of ethanol. This process leads to a decrease in the NAD+/NADH ratio and the generation of reactive oxygen species. A systematic review and meta-analysis were conducted to investigate the role of oxidative stress in AFLD. A total of 201 eligible manuscripts were included, which revealed that animals with AFLD exhibited elevated expression of CYP2E1, decreased enzymatic activity of antioxidant enzymes, and reduced levels of the transcription factor Nrf2, which plays a pivotal role in the synthesis of antioxidant enzymes. Furthermore, animals with AFLD exhibited increased levels of lipid peroxidation markers and carbonylated proteins, collectively contributing to a weakened antioxidant defense and increased oxidative damage. The liver damage in AFLD was supported by significantly higher activity of alanine and aspartate aminotransferase enzymes. Moreover, animals with AFLD had increased levels of triacylglycerol in the serum and liver, likely due to reduced fatty acid metabolism caused by decreased PPAR-α expression, which is responsible for fatty acid oxidation, and increased expression of SREBP-1c, which is involved in fatty acid synthesis. With regard to inflammation, animals with AFLD exhibited elevated levels of pro-inflammatory cytokines, including TNF-a, IL-1β, and IL-6. The heightened oxidative stress, along with inflammation, led to an upregulation of cell death markers, such as caspase-3, and an increased Bax/Bcl-2 ratio. Overall, the findings of the review and meta-analysis indicate that ethanol metabolism reduces important markers of antioxidant defense while increasing inflammatory and apoptotic markers, thereby contributing to the development of AFLD.

Transcriptome and proteomics conjoint analysis reveal anti-alcoholic liver injury effect of Dianhong Black Tea volatile substances

Dianhong Black Tea, a fermented tea containing various bioactive ingredients, has been found to have a significant role in alleviating alcoholic liver injury (ALI). One of its main unique components, Dianhong Black Tea volatile substances (DBTVS), may have potential anti-ALI effects. However, its effects and underlying molecular mechanisms are still unknown. In this study, we aimed to investigate the potential of DBTVS as an anti-ALI agent using alcohol-fed rats. We assessed the effect of DBTVS on ALI by analyzing serum transaminase and lipid levels, as well as conducting hematoxylin-eosin and oil red O staining. Additionally, GC-MS was used to detect the components of DBTVS, while transcriptome, proteomics analysis, Western blot, and molecular docking were employed to uncover the underlying mechanisms. Our results demonstrated that DBTVS significantly reduced serum ALT and AST levels and improved lipid metabolism disorders. Moreover, we identified 14 components in DBTVS, with five of them exhibiting strong binding affinity with key proteins. These findings suggested that DBTVS could be a promising agent for the prevention and treatment of ALI. Its potential therapeutic effects may be attributed to its ability to regulate lipid metabolism through the PPAR signaling pathway.

Are silymarin and N-acetylcysteine able to prevent liver damage mediated by multiple factors? Findings against ethanol plus LPS-induced liver injury in mice

This study investigated the effect of N-acetylcysteine (NAC) and silymarin (SIL) in the liver of mice exposed to ethanol and lipopolysaccharides (LPS). Mice were divided into four groups (n = 6): naive, vehicle, NAC (200 mg/kg), and SIL (200 mg/kg). Treatments were given orally (po) once daily for 10 days. Liver injury was induced by administration of ethanol (30%, po) for 10 days, once daily, followed by a single administration of LPS (2 mg/kg, ip) 24 h before euthanasia. After the treatment period, animals were euthanized, and liver and blood samples were collected. NAC, but not SIL, prevented the increase in oxalacetic glutamic transaminase (OGT) and pyruvic glutamic transaminase (PGT) serum levels. NAC and SIL did not restore levels of reduced glutathione or hepatic malonaldehyde. The treatments with NAC or SIL showed no difference in the activity of glutathione S-transferase, superoxide dismutase, and catalase compared to vehicle group. Myeloperoxidase and N-acetylglucosaminidase activities are increased, as well as the IL-6 and IL-10 levels in the liver. The treatment with NAC, but not SIL, reduced the N-acetylglucosamines activity and the IL-6 and IL-10 amount in the liver. Histological findings revealed microsteatosis in the vehicle group, which was not prevented by SIL but was partially reduced in animals receiving NAC. Unlike other liver injury models, NAC (200 mg/kg) or SIL (200 mg/kg) did not positively affect antioxidant patterns in liver tissue of animals exposed to ethanol plus LPS, but NAC treatment displays anti-inflammatory properties in this model.

Total saponins from Panax japonicus attenuate acute alcoholic liver oxidative stress and hepatosteatosis by p62-related Nrf2 pathway and AMPK-ACC/PPARα axis in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Panax japonicus (T. Nees) C.A. Mey. (PJ) has been used as a tonic traditional Chinese medicine (TCM) for years. Based on its meridian tropism in liver, spleen, and lung, PJ was popularly used to enhance the function of these organs. It is originally recorded with detoxicant effect on binge drink in Ben Cao Gang Mu Shi Yi, a persuasive Chinese materia medica. And binge dink has a close relationship with alcoholic liver disease (ALD). Hence, it's meaningful to investigate whether PJ exerts liver protection against binge drink toxicity.

AIM OF THE STUDY

This investigation was carried out not only to emphasize the right recognition of total saponins from PJ (SPJ), but also to study on its sober-up effectiveness and defensive mechanism against acute alcoholic liver injury in vivo and in vitro.

MATERIALS AND METHODS

SPJ constituents were verified by HPLC-UV analysis. In vivo, acute alcoholic liver oxidative stress and hepatosteatosis were established by continuous ethanol gavage to C57BL/6 mice for 3 days. SPJ was pre-administered for 7 days to investigate its protective efficacy. Loss of righting reflex (LORR) assay was employed to assess anti-inebriation effect of SPJ. Transaminases levels and hematoxylin and eosin (H&E) staining were measured to indicate the alcoholic liver injury. Antioxidant enzymes were measured to evaluate the oxidative stress degree in liver. Measurement of hepatic lipid accumulation was based on Oil Red O staining. Levels of inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA). In vitro, HepG2 cells were treated with ethanol for 24 h, and SPJ was pre-administered for 2 h. 2,7-dichlorofluorescein diacetate (DCFH-DA) was used as a probe to indicate reactive oxygen species (ROS) generation. Nrf2 activation was verified by the favor of specific inhibitor, ML385. The nuclear translocation of Nrf2 was indicated with immunofluorescence analysis. Proteins expressions of related pathways were determined by Western blotting.

RESULTS

Oleanane-type saponins are the most abundant constituents of SPJ. In this acute model, SPJ released inebriation of mice in a dose dependent manner. It decreased levels of serum ALT and AST, and hepatic TG. Besides, SPJ inhibited CYP2E1 expression and reduced MDA level in liver, with upregulations of antioxidant enzymes GSH, SOD and CAT. p62-related Nrf2 pathway was activated by SPJ with downstream upregulations of GCLC and NQO1 in liver. AMPK-ACC/PPARα axis was upregulated by SPJ to alleviate hepatic lipidosis. Hepatic IL-6 and TNF-α levels were downregulated by SPJ, which indicated a regressive lipid peroxidation in liver. In HepG2 cells, SPJ reduced ethanol-exposed ROS generation. Activated p62-related Nrf2 pathway was verified to contribute to the alleviation of alcohol-induced oxidative stress in hepatic cells.

CONCLUSION

This attenuation of hepatic oxidative stress and steatosis suggested the therapeutic value of SPJ for ALD.

Indole-3-acetamide from gut microbiota activated hepatic AhR and mediated the remission effect of Lactiplantibacillus plantarum P101 on alcoholic liver injury in mice

Alcoholic liver disease is a prevalent condition resulting from excessive alcohol consumption, characterized by hepatic lipid accumulation and inflammation. This study delved into the protective effects and mechanisms of L. plantarum P101 on alcoholic liver injury in mice. As a result, L. plantarum P101 intervention reduced ALT and AST release, indicative of hepatocyte injury alleviation, while enhancing the activity of the antioxidant enzymes SOD and CAT. A reduction in pro-inflammatory cytokine TNF-α and an increase in anti-inflammatory cytokine IL-10 levels were observed in the L. plantarum P101-intervened mouse liver, signifying reduced inflammation within the mice. Furthermore, L. plantarum P101 intervention altered the gut microbial composition, primarily marked by an increase in Bacteroidota abundance, along with significant enrichment of beneficial bacteria, including Coprostanoligenes, Blautia and Lactiplantibacillus. Correlation analysis unveiled connections between serum tryptophan metabolites and the altered gut microbiota genera, suggesting that gut microbiota-driven effects may extend to extraintestinal organs through their metabolites. Intriguingly, serum indole-3-acetamide (IAM) was elevated by L. plantarum P101-regulated gut microbiota. Subsequently, the role of IAM in ameliorating alcoholic injury was explored using HepG2 cells, where it bolstered cell viability and attenuated EtOH-induced oxidative damage. Concomitantly, IAM activated the gene and protein expression of AhR in cells. Likewise, hepatic AhR expression in mice subjected to L. plantarum P101 significantly up-regulated, possibly instigated by gut microbiota-mediated IAM. Collectively, L. plantarum P101 orchestrates a modulation of gut microbiota and its metabolites, particularly IAM, to activate AhR, thereby alleviating alcoholic liver injury.

Effect of natural polysaccharides on alcoholic liver disease: A review

In this study, we systematically collected relevant literature in the past five years on the intervention of natural polysaccharides in alcoholic liver disease (ALD) and reviewed the pharmacological activities and potential mechanisms of action. Natural polysaccharides are effective in preventing liver tissue degeneration, inhibiting the alcohol-induced expression of inflammatory factors, inactivation of antioxidant enzymes, and abnormal hepatic lipid deposition. Natural polysaccharides regulate the expression of proteins, such as tight junction proteins, production of small molecule metabolites, and balance of intestinal flora in the intestinal tract to alleviate ALD. Natural polysaccharides also exert therapeutic effects by modulating inflammatory, oxidative, lipid metabolism, and other pathways in the liver. Natural polysaccharides also inhibit alcohol-induced intestinal abnormalities by regulating intestinal flora and feeding back into the liver via the gut-liver axis. However, existing research on natural polysaccharides has many shortcomings: for example, most of the natural polysaccharides for testing are total polysaccharides or crude polysaccharides, progress in research on in vivo metabolic processes and mechanisms is slow, and the degree of industrialisation is insufficient. Finally, we discuss the difficulties in studying natural polysaccharides and future directions to provide a theoretical basis for their development and application.

Pathogenesis of Alcoholic Fatty Liver a Narrative Review

Alcohol effect hepatic lipid metabolism through various mechanisms, leading synergistically to an accumulation of fatty acids (FA) and triglycerides. Obesity, as well as dietary fat (saturated fatty acids (FA) versus poly-unsaturated fatty acids (PUFA)) may modulate the hepatic fat. Alcohol inhibits adenosine monophosphate activated kinase (AMPK). AMPK activates peroxisome proliferator activated receptor a (PPARα) and leads to a decreased activation of sterol regulatory element binding protein 1c (SRABP1c). The inhibition of AMPK, and thus of PPARα, results in an inhibition of FA oxidation. This ß-oxidation is further reduced due to mitochondrial damage induced through cytochrome P4502E1 (CYP2E1)-driven oxidative stress. Furthermore, the synthesis of FAs is stimulated through an activation of SHREP1. In addition, alcohol consumption leads to a reduced production of adiponectin in adipocytes due to oxidative stress and to an increased mobilization of FAs from adipose tissue and from the gut as chylomicrons. On the other side, the secretion of FAs via very-low-density lipoproteins (VLDL) from the liver is inhibited by alcohol. Alcohol also affects signal pathways such as early growth response 1 (Egr-1) associated with the expression of tumour necrosis factor α (TNF α), and the mammalian target of rapamycin (mTOR) a key regulator of autophagy. Both have influence the pathogenesis of alcoholic fatty liver. Alcohol-induced gut dysbiosis contributes to the severity of ALD by increasing the metabolism of ethanol in the gut and promoting intestinal dysfunction. Moreover, pathogen-associated molecular patterns (PAMPS) via specific Toll-like receptor (TLR) bacterial overgrowth leads to the translocation of bacteria. Endotoxins and toxic ethanol metabolites enter the enterohepatic circulation, reaching the liver and inducing the activation of the nuclear factor kappa-B (NFκB) pathway. Pro-inflammatory cytokines released in the process contribute to inflammation and fibrosis. In addition, cellular apoptosis is inhibited in favour of necrosis.

HMGA2 knockdown alleviates the progression of nonalcoholic fatty liver disease (NAFLD) by downregulating SNAI2 expression

Non-alcoholic fatty liver disease (NAFLD) is a complex disease that is considered as the next major health epidemic with alarmingly increasing global prevalence. To explore the pathogenesis of NAFLD, data from GSE118892 were analyzed. High mobility group AT-hook 2 (HMGA2), a member of the high mobility group family, is declined in liver tissues of NAFLD rats. However, its role in NAFLD remains unknown. This study attempted to identify the multiple roles of HMGA2 in NAFLD process. NAFLD was induced in rats using a high-fat diet (HFD). In vivo, HMGA2 knockdown using adenovirus system attenuated liver injury and liver lipid deposition, accompanied by decreased NAFLD score, increased liver function, and decreased CD36 and FAS, indicating the deceleration of NAFLD progression. Moreover, HMGA2 knockdown restrained liver inflammation by decreasing the expression of related inflammatory factors. Importantly, HMGA2 knockdown attenuated liver fibrosis via downregulating the expression of fibrous proteins, and inhibiting the activation of TGF-β1/SMAD signaling pathway. In vitro, HMGA2 knockdown relieved palmitic acid (PA)-induced hepatocyte injury and attenuated TGF-β1-induced liver fibrosis, consistent with in vivo findings. Strikingly, HMGA2 activated the transcription of SNAI2, which was evidenced by the dual luciferase assays. Moreover, HMGA2 knockdown largely downregulated SNAI2 levels. Indeed, SNAI2 overexpression effectively blocked the inhibitory effect of HMGA2 knockdown on NAFLD. Totally, our findings reveal that HMGA2 knockdown alleviates the progression of NAFLD by directly regulating the transcription of SNAI2. HMGA2 inhibition may emerge as a potential therapeutic target for NAFLD.

Pathogenic mechanisms and regulatory factors involved in alcoholic liver disease

Alcoholism is a widespread and damaging behaviour of people throughout the world. Long-term alcohol consumption has resulted in alcoholic liver disease (ALD) being the leading cause of chronic liver disease. Many metabolic enzymes, including alcohol dehydrogenases such as ADH, CYP2E1, and CATacetaldehyde dehydrogenases ALDHsand nonoxidative metabolizing enzymes such as SULT, UGT, and FAEES, are involved in the metabolism of ethanol, the main component in alcoholic beverages. Ethanol consumption changes the functional or expression profiles of various regulatory factors, such as kinases, transcription factors, and microRNAs. Therefore, the underlying mechanisms of ALD are complex, involving inflammation, mitochondrial damage, endoplasmic reticulum stress, nitrification, and oxidative stress. Moreover, recent evidence has demonstrated that the gut-liver axis plays a critical role in ALD pathogenesis. For example, ethanol damages the intestinal barrier, resulting in the release of endotoxins and alterations in intestinal flora content and bile acid metabolism. However, ALD therapies show low effectiveness. Therefore, this review summarizes ethanol metabolism pathways and highly influential pathogenic mechanisms and regulatory factors involved in ALD pathology with the aim of new therapeutic insights.

Liver Injury Traceability: Spatiotemporally Monitoring Oxidative Stress Processes by Unit-Emitting Carbon Dots

Exploring the etiology of liver injury is critical to fundamental science and precise treatment, which has not yet been achieved by molecule imaging techniques. Herein, we manage to conquer this challenge by spatiotemporally monitoring oxidative stress processes using the proposed unit-emitting carbon dots (UE-C-dots) as fluorescent probes. We discover and reveal that the UE-C-dots can specifically determine hypochlorous acid (HClO) molecules, one of the important reactive oxygen/nitrogen species (ROS/RNS) in liver injury, by an excited state oxidation mechanism. Other ROS/RNS do not interfere with the assay even if their concentrations are 1000 times higher than that of HClO due to the lowest unoccupied molecular orbital level mismatch. Real-time tomographic imaging demonstrates that different stimuli cause distinctly different HClO bursts in both temporal and spatial dimensionalities. Therefore, the measurement and analysis of temporal information substantially extend our understanding on the relationships of hepatic oxidative stress and corresponding physiological/pathological behaviors.

Hif-2α regulates lipid metabolism in alcoholic fatty liver disease through mitophagy

BACKGROUND

Disordered lipid metabolism plays an essential role in both the initiation and progression of alcoholic fatty liver disease (AFLD), and fatty acid β-oxidation is increasingly considered as a crucial factor for controlling lipid metabolism. Hif-2α is a member of the Hif family of nuclear receptors, which take part in regulating hepatic fatty acid β-oxidation. However, its functional role in AFLD and the underlying mechanisms remain unclear.

RESULTS

Hif-2α was upregulated in EtOH-fed mice and EtOH-treated AML-12 cells. Inhibition or silencing of Hif-2α led to increased fatty acid β-oxidation and BNIP3-dependent mitophagy. Downregulation of Hif-2α activates the PPAR-α/PGC-1α signaling pathway, which is involved in hepatic fatty acid β-oxidation, by mediating BNIP3-dependent mitophagy, ultimately delaying the progression of AFLD.

CONCLUSIONS

Hif-2α induces liver steatosis, which promotes the progression of AFLD. Here, we have described a novel Hif-2α-BNIP3-dependent mitophagy regulatory pathway interconnected with EtOH-induced lipid accumulation, which could be a potential therapeutic target for the prevention and treatment of AFLD.

Integrated strategy of network pharmacology, molecular docking, HPLC-DAD and mice model for exploring active ingredients and pharmacological mechanisms of Penthorum chinense Pursh against alcoholic liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Penthorum chinense Pursh (PCP, Saxifragaceae) is an edible plant and frequently-used Chinese herbal medicine, and is commonly used as Miao medicine in China. It showed well effect on alcoholic liver injury (ALI), but studies on its active ingredients and mechanisms against ALI remain at the starting stage.

AIM OF THE STUDY

This work aims to explore the active ingredients and pharmacological mechanisms of PCP against ALI.

MATERIALS AND METHODS

First, network pharmacology was applied to decipher the potential active ingredients and pharmacological mechanisms of PCP against ALI by ingredient identification, ADMET evaluation, target identification, network construction and analysis, protein-protein interaction (PPI) analysis, and gene enrichment analysis. Second, molecular docking was used to explore the interaction between key active ingredient and hub protein of PCP against ALI. Then, the ingredient analysis of PCP aqueous extract and semiquantitative analysis of key active ingredient were carried out on HPLC-DAD. Subsequently, mice with ALI were used to investigate the therapeutic effect or verify the predicted mechanisms of PCP or key active ingredient against ALI by analyzing body weight, liver index, ALT and AST activities in serum and liver tissues, oxidation related indices (SOD activity, GSH level and MDA level) in liver tissues, histopathology of liver tissues (oil red O, hematoxylin-eosin and DAB-TUNEL staining), and changes of related proteins (PI3K, Akt, p-Akt, Bax and Bcl-2) in liver tissues with the aid of Western blot.

RESULTS

Network pharmacology showed that the active ingredients and related genes of PCP against ALI comprised 10 ingredients and 52 genes. Based on the result of ingredient analysis of PCP aqueous extract, quercitrin was identified as the key active ingredient of PCP against ALI. PPI analysis indicated that AKT1 was the hub gene of PCP against ALI, and molecular docking suggested that there were good interaction between quercetin and Akt1 protein. Gene enrichment analysis showed that the pivotal molecular mechanism of PCP against ALI might be to inhibit hepatocyte apoptosis via activation of PI3K-Akt signaling pathway. PCP and quercitrin showed anti-ALI effect by offsetting weight loss and increase of liver index, and reversing the imbalance of oxidative stress and histopathological changes of liver tissues (abnormal fatty acid metabolism, hepatic cord swelling and inflammatory cell infiltration) in mice with ALI. PCP caused the decrease of DAB-TUNEL-positive cells, upregulated the anti-apoptotic proteins (PI3K, Akt and p-Akt) levels and the ratio of p-Akt/Akt, and downregulated pro-apoptotic protein (Bax) level and the ratio of Bax/Bcl-2 in liver tissues of mice with ALI, indicating that the mechanism of PCP against ALI involved in inhibiting hepatocyte apoptosis via activation of PI3K-Akt signaling pathway.

CONCLUSION

PCP and quercitrin showed well anti-ALI effect. The key active ingredient of PCP against ALI was identified as quercitrin. The underlying pharmacological mechanisms of PCP against ALI may be related to PI3K-Akt signaling pathway-mediated inhibition of hepatocyte apoptosis. This work provided new evidence to support the application of PCP in treatment of ALI, and a research basis for the research and development of functional foods or drugs against ALI from PCP.

Ginsenoside Rc Modulates SIRT6-NRF2 Interaction to Alleviate Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a serious worldwide health problem. Ginsenoside Rc is a major active ingredient isolated from Panax ginseng, whose pharmacological effects counteract oxidative stress, inflammation, and lipid accumulation. However, it is still unclear whether ginsenoside Rc might exert beneficial effects on alcohol-induced liver injury. To this aim, mice primary hepatocytes (MPHs) were challenged with alcohol to test ginsenoside Rc's effects on their intracellular alcohol metabolism. C57BL/6J mice or SIRT6alb-/- mice were chronically fed a diet with added alcohol or given a single gavage of alcohol with or without ginsenoside Rc. Analyses of alcohol metabolism, oxidative stress, inflammation, lipid metabolism, and RNaseq expression were conducted to explore potential targets exploited by ginsenoside Rc to protect against ALD. Our results showed that ginsenoside Rc attenuated alcohol-induced liver injury by regulating oxidative stress, inflammation, and lipid accumulation both in vivo and in vitro. Ginsenoside Rc did increase the deacetylase activity of SIRT6, thereby lowering acetylated NRF2 levels, which elevated NRF2's stability, and subsequently exerting an antioxidant effect. In keeping with this, the hepatic knockout of SIRT6 almost abolished the hepatoprotective effects of ginsenoside Rc against ALD. Therefore, our results suggest that ginsenoside Rc attenuated hepatocytes' damage and oxidative stress in ALD by up-regulating the SIRT6/NRF2 pathway. Hence, ginsenoside Rc may be a promising drug to treat or relieve ALD.

Croton urucurana Baill. Ameliorates Metabolic Associated Fatty Liver Disease in Rats

Background: Metabolic associated fatty liver disease (MAFLD) affects a quarter of the worldwide population, but no drug therapies have yet been developed. Croton urucurana Baill. (Euphorbiaceae) is a medicinal species, that is, widely distributed in Brazil. It is used in popular medicine to treat gastrointestinal, cardiovascular, and endocrine system diseases. However, its hepatoprotective and lipid-lowering effects have not yet been scientifically investigated.

Aim of the study: The present study investigated the effects of an extract of C. urucurana in a rat model of MAFLD that was associated with multiple risk factors, including hypertension, smoking, and dyslipidemia.

Material and Methods: The phytochemical composition of C. urucurana was evaluated by liquid chromatography-mass spectrometry. Spontaneously hypertensive rats received a 0.5% cholesterol-enriched diet and were exposed to cigarette smoke (9 cigarettes/day for 10 weeks). During the last 5 weeks, the animals were orally treated with vehicle (negative control [C-] group), C. urucurana extract (30, 100, and 300 mg/kg), or simvastatin + enalapril (two standard reference drugs that are commonly used to treat dyslipidemia and hypertension, respectively). One group of rats that were not exposed to these risk factors was also evaluated (basal group). Blood was collected for the analysis of cholesterol, triglyceride, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels. The liver and feces were collected for lipid quantification. The liver was also processed for antioxidant and histopathological analysis.

Results: The main constituents of the C. urucurana extract were flavonoids, glycosides, and alkaloids. The model successfully induced MAFLD, reflected by increases in AST and ALT levels, and induced oxidative stress in the C- group. Treatment with the C. urucurana extract (300 mg/kg) and simvastatin + enalapril decreased plasma and hepatic lipid levels. In contrast to simvastatin + enalapril treatment, C. urucurana reduced AST and ALT levels. Massive lesions were observed in the liver in the C- group, which were reversed by treatment with the C. urucurana extract (300 mg/kg).

Conclusion:C. urucurana extract exerted promising hepatoprotective and lipid-lowering effects in a preclinical rat model of MAFLD.

Diallyl disulfide ameliorates ethanol-induced liver steatosis and inflammation by maintaining the fatty acid catabolism and regulating the gut-liver axis

Diallyl disulfide (DADS) has been suggested to possess hepatoprotection against alcoholic liver disease (ALD) by a couple of pilot studies, while the underlying mechanisms remain largely unknown. This study aimed to investigate the hepatoprotective effects of DADS against ethanol-induced liver steatosis and early inflammation by using the chronic-plus-binge mice model and cultured J774A.1 macrophages and AML12 hepatocytes. We found that DADS significantly attenuated ethanol-induced elevation of serum aminotransferase activities, accumulation of liver triglyceride, hepatocytes apoptosis, oxidative stress, infiltration of macrophages and neutrophils, and proinflammatory polarization of macrophages in mice livers. In addition, chronic-plus-binge drinking induced apparent intestinal mucosa damage and disturbance of gut microbiota, endotoxemia, and activation of hepatic NF-κB signaling and NLRP3 inflammasome, which was inhibited by DADS. In vitro studies using cocultured AML12/J774A.1 cells showed that DADS suppressed ethanol/LPS-induced cell injury and inflammatory activation of macrophages. Furthermore, DADS ameliorated ethanol-induced decline of peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase 1 (CPT1), and phosphorylated AMP-activated protein kinase (AMPK) protein levels in mice liver and AML12 cells. These results demonstrate that DADS could prevent ethanol-induced liver steatosis and early inflammation by regulating the gut-liver axis and maintaining fatty acid catabolism.

Glial cell line-derived neurotrophic factor contributes to alcoholic-induced liver injury by regulating the NF-κB pathway

BACKGROUND

Alcoholic liver disease (ALD) is associated with high morbidity and mortality worldwide. The pathogenesis of ALD is not completely understood. Although accumulating evidence suggests an important role of glial cell line-derived neurotrophic factor (GDNF) in several diseases, there are no data concerning its role in ALD. This study compared patients with ALD with control subjects and used a mouse model and a cell culture model to investigate the function of GDNF in ALD and its mechanism of action in hepatocyte injury.

METHODS

Serum levels of GDNF were measured in 25 patients with ALD and 25 healthy control subjects. A 4-week Lieber-DeCarli ethanol (EtOH) liquid diet combined with the Gao-Binge model was used in the mouse study. Mouse primary hepatocytes and Huh-7 cells were used for cell experiments. The parameters of liver injury, inflammatory cytokines, and lipid metabolism were measured.

RESULTS

Patients with alcoholic hepatitis had higher serum GDNF than control subjects. Expression of GDNF mRNA and protein was markedly increased in mice in the chronic-plus-binge ALD mouse model. The level of GDNF mRNA was upregulated in primary hepatic stellate cells isolated from ethanol-fed mouse liver. Ethanol induced GDNF expression in LX2 cells. The levels of inflammatory cytokines (tumor necrosis factor α, interleukin 1β, and monocyte chemotactic protein 1) were significantly increased after GDNF stimulation in primary hepatocytes and Huh-7 cells. After GDNF stimulation, levels of both p-AKT and p-NF-κB were significantly increased in primary hepatocytes and Huh-7 cells. The NF-κB activity induced by GDNF was significantly decreased by an NF-κB inhibitor, which limited hepatocyte injury and inflammation.

CONCLUSIONS

The concentration of GDNF is increased in the circulation of ALD patients. GDNF promotes alcohol-induced liver injury and inflammation via the activation of NF-κB, which mediates hepatocyte injury and inflammatory cytokine expression. Based on these findings, GDNF is a potential therapeutic target for preventing or ameliorating liver injury in ALD.

D-Mannose Regulates Hepatocyte Lipid Metabolism via PI3K/Akt/mTOR Signaling Pathway and Ameliorates Hepatic Steatosis in Alcoholic Liver Disease

This study investigated the protective properties and mechanisms of D-mannose against hepatic steatosis in experimental alcoholic liver disease (ALD). Drinking-water supplementation of D-mannose significantly attenuated hepatic steatosis in a standard mouse ALD model established by chronic-binge ethanol feeding, especially hepatocyte lipid deposition. This function of D-mannose on lipid accumulation in hepatocytes was also confirmed using ethanol-treated primary mouse hepatocytes (PMHs) with a D-mannose supplement. Meanwhile, D-mannose regulated lipid metabolism by rescuing ethanol-mediated reduction of fatty acid oxidation genes (PPARα, ACOX1, CPT1) and elevation of lipogenic genes (SREBP1c, ACC1, FASN). PI3K/Akt/mTOR signaling pathway was involved in this effect of D-mannose on lipid metabolism since PI3K/Akt/mTOR pathway inhibitors or agonists could abolish this effect in PMHs. Overall, our findings suggest that D-mannose exhibits its anti-steatosis effect in ALD by regulating hepatocyte lipid metabolism via PI3K/Akt/mTOR signaling pathway.

Chronic alcohol exposure induces hepatocyte damage by inducing oxidative stress, SATB2 and stem cell‐like characteristics, and activating lipogenesis

Alcohol is a risk factor for hepatocellular carcinoma (HCC). However, the molecular mechanism by which chronic alcohol consumption contributes to HCC is not well understood. The purpose of the study was to demonstrate the effects of chronic ethanol exposure on the damage of human normal hepatocytes. Our data showed that chronic exposure of hepatocytes with ethanol induced changes similar to transformed hepatocytes that is, exhibited colonies and anchorage‐independent growth. These damaged hepatocytes contained high levels of reactive oxygen species (ROS) and showed induction of the SATB2 gene. Furthermore, damaged hepatocytes gained the phenotypes of CSCs which expressed stem cell markers (CD133, CD44, CD90, EpCAM, AFP and LGR5), and pluripotency maintaining factors (Sox‐2, POU5F1/Oct4 and KLF‐4). Ethanol exposure also induced Nanog, a pluripotency maintaining transcription factor that functions in concert with Oct4 and SOX‐2. Furthermore, ethanol induced expression of EMT‐related transcription factors (Snail, Slug and Zeb1), N‐Cadherin, and inhibited E‐cadherin expression in damaged hepatocytes. Ethanol enhanced recruitment of SATB2 to promoters of Bcl‐2, Nanog, c‐Myc, Klf4 and Oct4. Ethanol also induced activation of the Wnt/TCF‐LEF1 pathway and its targets (Bcl‐2, Cyclin D1, AXIN2 and Myc). Finally, ethanol induced hepatocellular steatosis, SREBP1 transcription, and modulated the expression of SREBP1c, ACAC, ACLY, FASN, IL‐1β, IL‐6, TNF‐α, GPC3, FLNB and p53. These data suggest that chronic alcohol consumption may contribute towards the development of HCC by damaging normal hepatocytes with the generation of inflammatory environment, induction of SATB2, stem cell‐like characteristics, and cellular steatosis.

The Study of Yin-Chen-Hao-Tang Preventing and Treating Alcoholic Fatty Liver Disease through PPAR Signaling Pathway Based on Network Pharmacology and RNA-Seq Transcriptomics

BACKGROUND

Alcoholic fatty liver disease (AFLD) is the first stage of the alcoholic liver disease course. Yin-Chen-Hao-Tang (YCHT) has a good clinical effect on the treatment of AFLD, but its molecular mechanism has not been elucidated. In this study, we tried to explore the molecular mechanism of YCHT in improving hepatocyte steatosis in AFLD mice through network pharmacology and RNA sequencing (RNA-Seq) transcriptomics.

METHODS

Network pharmacological methods were used to analyze the potential therapeutic signaling pathways and targets of YCHT on AFLD. Then, the AFLD mice model was induced and YCHT was administered concurrently. Liver injury was measured by serum alanine aminotransferase (ALT) activity and liver tissue H&E staining, and liver steatosis was determined by serum triglyceride (TG) level and liver tissue Oil Red staining. The molecular mechanism of YCHT on prevention and treatment of mice AFLD was investigated according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the differential expression genes data obtained by liver tissue RNA-Seq. Finally, ethanol-induced AFLD AML12 hepatocyte model was established, YCHT with or without PPARα agonist pemafibrate or PPARγ inhibitor GW9662 was administered, Nile Red fluorescent staining was used to evaluate steatosis levels in AML12 hepatocytes, and qRT-PCR was used to detect PPARα and PPARγ gene expression.

RESULTS

The results of network pharmacology analysis showed that YCHT may exert its pharmacological effect on AFLD through 312 potential targets which are involved in many signaling pathways including the PPAR signaling pathway. AFLD mice experiments results showed that YCHT markedly decreased mice serum ALT activity and serum TG levels. YCHT also significantly improved alcohol-induced hepatic injury and steatosis in mice livers. Furthermore, KEGG pathway enrichment results of RNA-Seq showed that the PPAR signaling pathway should be the most relevant pathway of YCHT in the prevention and treatment of AFLD. AFLD hepatocyte model experiment results showed that YCHT could remarkably reduce hepatocyte steatosis through reducing PPARγ expression and increasing PPARα expression.

CONCLUSIONS

Our study discovered that PPARγ and PPARα are the key targets and the PPAR signaling pathway is the main signaling pathway for YCHT to prevent and treat AFLD.

Camel milk ameliorates inflammatory mechanisms in an alcohol-induced liver injury mouse model

Camel milk (CM) is considered to protect the liver in the practice of traditional medicine in nomadic areas. The purpose of the present study was to investigate the effects of CM on the hepatic biochemical and multiple omics alterations induced by chronic alcoholic liver disease (ALD). An intragastric gavage mice Lieber DeCarli + Gao binge model (NIAAA model) was employed to investigate the inflammatory mechanism of camel milk on the liver tissue of mice. A gut microbiota of the feces of mice and transcriptomic and proteomic analyses of the liver of mice were performed. Analysis of serum and liver biochemical indexes revealed that camel milk not only prevents alcohol-induced colonic dysfunction and lipid accumulation, but also regulates oxidative stress and inflammatory cytokine production to protect against chronic ALD in mouse. The gut microbial community of mice treated with camel milk was more similar to the untreated control group than to the model group, indicating that the intake of camel milk pre- and post-alcohol gavage effectively prevents and alleviates the intestinal microbial disorder caused by chronic alcoholism in mice. Furthermore, the results of the transcriptomic and proteomic analyses of the liver tissue showed that camel milk can improve alcoholic liver injury in mice by regulating inflammatory factors and immune system disruptions. This study provides insights into the molecular mechanism by which camel milk can be developed as a potential functional food with no side effects and against liver injury.

Oxidative Stress-A Key Player in the Course of Alcohol-Related Liver Disease

Oxidative stress is known to be an inseparable factor involved in the presentation of liver disorders. Free radicals interfere with DNA, proteins, and lipids, which are crucial in liver metabolism, changing their expression and biological functions. Additionally, oxidative stress modifies the function of micro-RNAs, impairing the metabolism of hepatocytes. Free radicals have also been proven to influence the function of certain transcriptional factors and to alter the cell cycle. The pathological appearance of alcohol-related liver disease (ALD) constitutes an ideal example of harmful effects due to the redox state. Finally, ethanol-induced toxicity and overproduction of free radicals provoke irreversible changes within liver parenchyma. Understanding the underlying mechanisms associated with the redox state in the course of ALD creates new possibilities of treatment for patients. The future of hepatology may become directly dependent on the effective action against reactive oxygen species. This review summarizes current data on the redox state in the natural history of ALD, highlighting the newest reports on this topic.

Bmal1 Regulates Macrophage Polarize Through Glycolytic Pathway in Alcoholic Liver Disease

Hepatic macrophages play a critical role in inflammation caused by alcohol feeding. During this process, variation of macrophage phenotypes triggers inflammatory responses in a variety of ways. Moreover, there is increasing evidence that Brain and Muscle Arnt-Like Protein-1 (Bmal1) is regarded as a key regulator of macrophage transformation. In our study, Bmal1 was detected to be low expressed in EtOH-fed mice tissue samples and ethanol-induced RAW264.7 cells. After hepatic specific overexpression of Bmal1, M1 macrophage markers were evidently down-regulated, while M2 markers were on the contrary, showing an upward trend. Furthermore, alcoholic liver lesions were also improved in alcohol feeding mice with overexpressed Bmal1. On this basis, we also found that the glycolytic pathway can regulate macrophage polarization. In vitro, blocking of glycolytic pathway can significantly inhibit M1-type polarization. Importantly, glycolysis levels were also restrained after Bmal1 overexpression. What’s more, Bmal1 exerts a negative regulatory effect on glycolysis by interacting with S100A9 protein. Further studies showed that the alleviation of alcoholic liver disease (ALD) by Bmal1 was associated with glycolytic pathway suppression and M1 macrophage polarization. In summary, we demonstrated that Bmal1 is a gene capable of relieving ALD, and this effect may provide new insights for altering macrophage phenotypes to regulate inflammatory responses in ALD.

Nrf2 in Neoplastic and Non-Neoplastic Liver Diseases

Simple Summary

Although the Keap1-Nrf2 pathway represents a powerful cell defense mechanism against a variety of toxic insults, its role in acute or chronic liver damage and tumor development is not completely understood. This review addresses how Nrf2 is involved in liver pathophysiology and critically discusses the contrasting results emerging from the literature. The aim of the present report is to stimulate further investigation on the role of Nrf2 that could lead to define the best strategies to therapeutically target this pathway.

Abstract

Activation of the Keap1/Nrf2 pathway, the most important cell defense signal, triggered to neutralize the harmful effects of electrophilic and oxidative stress, plays a crucial role in cell survival. Therefore, its ability to attenuate acute and chronic liver damage, where oxidative stress represents the key player, is not surprising. On the other hand, while Nrf2 promotes proliferation in cancer cells, its role in non-neoplastic hepatocytes is a matter of debate. Another topic of uncertainty concerns the nature of the mechanisms of Nrf2 activation in hepatocarcinogenesis. Indeed, it remains unclear what is the main mechanism behind the sustained activation of the Keap1/Nrf2 pathway in hepatocarcinogenesis. This raises doubts about the best strategies to therapeutically target this pathway. In this review, we will analyze and discuss our present knowledge concerning the role of Nrf2 in hepatic physiology and pathology, including hepatocellular carcinoma. In particular, we will critically examine and discuss some findings originating from animal models that raise questions that still need to be adequately answered.

Lipophagy: Molecular Mechanisms and Implications in Metabolic Disorders

Autophagy is an intracellular degradation system that breaks down damaged organelles or damaged proteins using intracellular lysosomes. Recent studies have also revealed that various forms of selective autophagy play specific physiological roles under different cellular conditions. Lipid droplets, which are mainly found in adipocytes and hepatocytes, are dynamic organelles that store triglycerides and are critical to health. Lipophagy is a type of selective autophagy that targets lipid droplets and is an essential mechanism for maintaining homeostasis of lipid droplets. However, while processes that regulate lipid droplets such as lipolysis and lipogenesis are relatively well known, the major factors that control lipophagy remain largely unknown. This review introduces the underlying mechanism by which lipophagy is induced and regulated, and the current findings on the major roles of lipophagy in physiological and pathological status. These studies will provide basic insights into the function of lipophagy and may be useful for the development of new therapies for lipophagy dysfunction-related diseases.

Roles of peroxisome proliferator-activated receptor α in the pathogenesis of ethanol-induced liver disease

Alcoholic liver disease (ALD) is a progressively aggravated liver disease with high incidence in alcoholics. Ethanol-induced fat accumulation and the subsequent lipopolysaccharide (LPS)-driven inflammation bring liver from reversible steatosis, to irreversible hepatitis, fibrosis, cirrhosis, and even hepatocellular carcinoma. Peroxisome proliferator-activated receptor α (PPARα) is a member of the nuclear receptor superfamily of ligand-activated transcription factors and plays pivotal roles in the regulation of fatty acid homeostasis as well as the inflammation control in the liver. It has been well documented that PPARα activity and/or expression are downregulated in liver of mice exposed to ethanol, which is thought to be one of the prime contributors to ethanol-induced steatosis, hepatitis and fibrosis. This article summarizes the current evidences from in vitro and animal models for the critical roles of PPARα in the onset and progression of ALD. Importantly, it should be noted that the expression of PPARα in human liver is reported to be similar to that in mice, and PPARα expression is downregulated in the liver of patients with nonalcoholic fatty liver disease (NAFLD), a disease sharing many similarities with ALD. Therefore, clinical trials investigating the expression of PPARα in the liver of ALD patients and the efficacy of strong PPARα agonists for the prevention and treatment of ALD are warranted.

Promising therapeutic use of Baccharis trimera (less.) DC. as a natural hepatoprotective agent against hepatic lesions that are caused by multiple risk factors

ETHNOPHARMACOLOGICAL RELEVANCE

Baccharis trimera (Less.) DC is a perennial subshrub, popularly known as "carqueja," that belongs to the Asteraceae family. Ethnobotanical studies indicate that this species is used for the treatment of diabetes and digestive and liver diseases. However, studies that sought to validate its popular use were conducted using ethanolic extracts of the plant, which does not reflect the ethnomedicinal use of this species in humans.

AIM OF THE STUDY

Non-alcoholic fatty liver disease (NAFLD) is characterized by triglyceride accumulation in the liver that can progress to cirrhosis and hepatocellular carcinoma. Because of the severity of this disease, less toxic and more effective therapeutic agents need to be developed. B. trimera may be a promising therapeutic alternative, but its activity against multiple risk factors for liver disease (e.g., smoking, dyslipidemia, and diabetes mellitus) has not been studied. The present study investigated the effects of an ethnomedicinal form of a B. trimera preparation in a rat model of NAFLD that is associated with multiple risk factors.

MATERIAL AND METHODS

Phytochemical analysis of the ethanolic soluble fraction of B. trimera extract was performed using ultra-performance liquid chromatography coupled to high-resolution mass spectrometry. Streptozotocin was used to induce diabetes in male Wistar rats. The rats received a 0.5% cholesterol-enriched diet and were exposed to cigarette smoke (9 cigarettes/day, 5 days/week, for 4 weeks). In the last 2 weeks, the animals were orally treated with vehicle (negative control group), B. trimera extract (30, 100, and 300 mg/kg), or insulin + simvastatin. One group of rats that was not exposed to these risk factors was also evaluated. Blood was collected for glucose, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) analysis. The liver and feces were collected for lipid quantification. The liver was additionally processed for histopathological analysis.

RESULTS

The model successfully induced NAFLD and increased levels of glucose, AST, and ALT in the negative control group. Treatment with the B. trimera extract (30 and 100 mg/kg) and insulin + simvastatin decreased hepatic and fecal lipids. In contrast to insulin + simvastatin treatment, all three doses of B. trimera effectively reduced AST and ALT levels.

CONCLUSION

B. trimera may be promising as a hepatoprotective agent against hepatic lesions that are caused by multiple risk factors.

Associations among liver disease, serum lipid profile, body mass index, ketonuria, meal skipping, and the alcohol dehydrogenase-1B and aldehyde dehydrogenase-2 genotypes in Japanese men with alcohol dependence

AIM

To elucidate associations among liver disease, lipid profile, body mass index (BMI), ketonuria, and meal skipping under the influence of alcohol dehydrogenase-1B (ADH1B; rs1229984) and aldehyde dehydrogenase-2 (ALDH2; rs671) genotypes in men with alcohol dependence.

METHODS

We investigated the associations among these variables in 1768 Japanese men with alcohol dependence. Serum lipid levels were followed up after abstinence.

RESULTS

The slow-metabolizing ADH1B Arg/Arg genotype and inactive ALDH2 Glu/Lys genotype increased the age- and drinking-adjusted odds ratio or regression coefficient for fatty liver, ketonuria, and serum high-density-lipoprotein cholesterol levels (HDL-C), and decreased these for cirrhosis and serum triglyceride levels (TG). The ADH1B Arg/Arg genotype increased the adjusted regression coefficient for BMI and non-HDL-C. In addition to the positive interlinkage among fatty liver, BMI, and atherogenic dyslipidemia, positive associations were observed of fatty liver with ketonuria and meal skipping, of cirrhosis with the BMI, and of ketonuria with non-HDL-C. Negative associations were observed of cirrhosis with fatty liver, TG, non-HDL-C, and HDL-C, and of ketonuria with BMI and TG. Overall, after admission for 4 or 6 weeks, the TG and HDL-C decreased, and the serum low-density lipoprotein cholesterol levels increased. However, there was no change of the serum low-density lipoprotein in the patients with cirrhosis or of the serum TG in those with fatty liver.

CONCLUSIONS

These associations and the alterations in lipid profile after abstinence serve as useful information for a better understanding of the clinical features of men with alcohol dependence.

Downregulation of mitogen-activated protein kinases (MAPKs) in chronic ethanol-induced fatty liver

Mitogen-activated protein kinases (MAPKs) are versatile proteins that have been suggested to be involved in the regulation of lipid metabolism. This study was designed to investigate the responses of MAPK signaling to chronic ethanol exposure in vivo and in vitro, and try to explore its role in the pathogenesis of alcoholic fatty liver (AFL). Mice were fed with Lieber-Decarli liquid diet (5% ethanol, w/v) for 4 weeks to induce fatty liver, and the chronological changes of MAPK phosphorylation were measured using western blotting. We found that chronic ethanol feeding led to accumulation of triglyceride (TG), decreased phosphorylation of MAPKs, decreased protein level of peroxisomal proliferator activation receptor α (PPARα), and increased protein expression of cytochrome P4502E1 (CYP2E1) in mice liver. In vitro study showed that overexpression of CYP2E1 blunted the response of MAPKs to ethanol, and MAPK phosphatase 1 (MKP-1) knockdown by siRNA led to upregulation of PPARα protein level. Lastly, epidermal growth factor (EGF), a well-known MAPK activator, significantly suppressed chronic ethanol-induced hepatic fat accumulation and decline of PPARα expression in mice liver. Collectively, MAPK suppression, possibly due to the activation of hepatic CYP2E1, may be involved in chronic ethanol-induced hepatic steatosis.

Sarcopoterium spinosum Inhibited the Development of Non-Alcoholic Steatosis and Steatohepatitis in Mice

Non-alcoholic fatty liver disease (NAFLD) is a comorbidity of obesity, which gradually develops from hepatic steatosis into steatohepatitis (NASH) and eventually even into fibrosis or hepatic carcinoma. To date, there has been no specific and effective treatment for NAFLD. Sarcopoterium spinosum extract (SSE) was found to improve insulin sensitivity. Recognizing the intimate link between insulin resistance and NAFLD, the aim of this study was to investigate the effectivity of SSE in the prevention and management of NAFLD at various severities. SSE was given to high-fat diet (HFD)-fed mice (steatosis model) or to mice given a Western diet (WD) in the short or long term (NASH prevention or treatment, respectively). SSE reduced body weight accumulation, improved glucose tolerance and insulin sensitivity and prevented the development of hepatic steatosis. SSE also blocked the progression of liver disease toward NASH in a dose-dependent manner. The expression of genes involved in lipid metabolism, inflammation, and antioxidant machinery was regulated by SSE in both models of steatosis and NASH development. However, SSE failed to reverse the hepatic damage in the advanced model of NASH. In summary, SSE might be considered as a botanical supplement for the prevention and treatment of hepatic steatosis, and for slowing the deterioration toward NASH.

Investigating the effect of Crocus sativus L. petal hydroalcoholic extract on inflammatory and enzymatic indices resulting from alcohol use in kidney and liver of male rats

Background

Studies have shown that consumption of high levels of alcohol causes many negative effects on the liver and kidneys where antioxidant ingredients can be a proper solution to reducing the resulting damages. So, the present study investigated the effect of hydroalcoholic extract of Crocus sativus L. (saffron) petal with antioxidant properties on the changes in inflammatory and enzymatic indices resulting from alcohol use in the male rats’ kidney and liver.

Materials and methods

After preparing the extract, LD₅₀ was determined and high-performance liquid chromatography (HPLC) was employed to specify the type and the rate of the active ingredients of the extract. Then, 36 male Wistar rats were randomly assigned into six groups (n=6). The first group was only administered with normal saline and the second group only received ethyl alcohol 6 mL/kg/day·BW. The third and the fourth groups received ethyl alcohol 6 mL/kg/day·BW plus 167.5 and 335 mg/kg/day·BW saffron petal extract for 8 weeks. The fifth and the sixth groups received ethyl alcohol 6 mL/kg/day·BW for the first 8 weeks and were subsequently gavage fed on saffron extract for 167.5 and 335 mg/kg/day·BW, respectively, during the next 8 weeks. In the beginning and after the termination of the treatment, blood samples were collected from all rats.

Results

The LD₅₀ of the extract was about 670 mg/kg. The HPLC results indicated that the extract contains important antioxidant ingredients. At the end of the study, the serum concentration of the inflammatory indices, renal enzymes, and hepatic enzymes experienced a significant reduction in all of the intervened groups compared to the negative control group (minimum significant difference: P<0.05) except for the treatment group 1.

Conclusion

Based on the current results, the extract has a protective effect in a dosage-dependent way and greater protective roles were documented for higher dosages.

Molecular Understanding of the Cardiomodulation in Myocardial Infarction and the Mechanism of Vitamin E Protections

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Myocardial infarction is a major cause of deaths globally. Modulation of several molecular mechanisms occurs during the initial stages of myocardial ischemia prior to permanent cardiac tissue damage, which involves both pathogenic as well as survival pathways in the cardiomyocyte. Currently, there is increasing evidence regarding the cardioprotective role of vitamin E in alleviating the disease. This fat-soluble vitamin does not only act as a powerful antioxidant; but it also has the ability to regulate several intracellular signalling pathways including HIF-1, PPAR-γ, Nrf-2, and NF-κB that influence the expression of a number of genes and their protein products. Essentially, it inhibits the molecular progression of tissue damage and preserves myocardial tissue viability. This review aims to summarize the molecular understanding of the cardiomodulation in myocardial infarction as well as the mechanism of vitamin E protection.

Emerging Roles of Lipophagy in Health and Disease

The term lipophagy is used to describe the autophagic degradation of lipid droplets, the main lipid storage organelles of eukaryotic cells. Ever since its discovery in 2009, lipophagy has emerged as a significant component of lipid metabolism with important implications for organismal health. This review aims to provide a brief summary of our current knowledge on the mechanisms that are responsible for regulating lipophagy and the impact the process has under physiological and pathological conditions.

Dihydroartemisinin attenuates alcoholic fatty liver through regulation of lipin-1 signaling

Alcoholic liver disease (ALD) is generated from excessive alcohol consumption, characterized by hepatic steatosis. Mechanistically, excessive hepatic lipid accumulation was attributed to the aberrant lipin-1 signaling during the development of alcoholic steatosis in rodent species and human. Dihydroartemisinin (DHA) has been recently identified to relieve hepatocytes necrosis and prevent from hepatic steatosis in alcohol-induced liver diseases; however, the role of DHA in ALD has not been elucidated completely. Therefore, this study was aimed to further identify the potential mechanisms of pharmacological effects of DHA on ALD. Results demonstrated that DHA regulated the expression and nucleocytoplasmic shuttling of lipin-1 in mice with chronic ethanol exposure. Results confirmed that the disruption of lipin-1 signaling abolished the suppression of DHA on alcohol-induced hepatic steatosis. Interestingly, DHA also significantly improved liver injury, and inflammation mediated by lipin-1 signaling in chronic alcohol-fed mice. in vivo experiments further consolidated the concept that DHA protected against hepatocyte lipoapoptosis dependent on the regulation of nucleocytoplasmic shuttling of lipin-1 signaling, resulting in attenuated ratio of Lpin1 β/α. Obvious increases in cell apoptosis were observed in alcohol-treated lipin1β-overexpressed mice. Although DHA attenuated cell apoptosis, overexpression of lipin-1β neutralized DHA action. DHA ameliorated activation of endoplasmic reticulum stress through inhibiting activation of JNK and CHOP, which was abrogated by overexpression of lipin-1β. In summary, DHA significantly improved liver injury, steatosis and hepatocyte lipoapoptosis in chronic alcohol-fed mice via regulation of lipin-1 signaling.

Aldose Reductase Inhibitors of Plant Origin in the Prevention and Treatment of Alcoholic Liver Disease: A Minireview

Alcoholic liver disease (ALD) is caused by heavy alcohol consumption over a long period. Acetaldehyde-mediated toxicity, oxidative stress, and imbalance of lipid metabolism are generally considered involved in the initiation of ALD. There is an increasing requirement for alternative and natural medicine to treat ALD. Recently, aldose reductase (AR) has been reported to be involved in the development of ALD by affecting inflammatory cytokines, oxidative stress, and lipid metabolism. Here, we review the effect of plant-derived AR inhibitors on ALD in rodents. And we conclude that AR inhibitors of plant origin may enhance antioxidant capacity, inhibit lipid peroxidation and inflammatory cytokines expression, and activate AMP-activated protein kinase thereby subsequently suppressing alcohol-induced lipid synthesis in liver to achieve ALD protection. This review reveals that natural AR inhibitor may be potential therapeutic agent for ALD.

Ameliorative effects of autophagy inducer, simvastatin on alcohol-induced liver disease in a rat model

Alcoholic liver disease (ALD) encompasses a variety of liver injuries with various underlying mechanisms but still no effective treatment. So we aimed to monitor the influence of simvastatin on alcohol-induced liver injury and elucidate the underlying mechanisms of its cytoprotective effect. Thirty male albino rats were randomly divided into five equal groups. Group 1 (control): received a standard diet; group 2: received simvastatin (10 mg kg^-1  day ^-1 ) once a day orally for 8 weeks; group 3: received 20% ethanol (7.9 g kg ^-1  day ^-1 ) daily orally for 8 weeks; group 4: received 20% ethanol along with same simvastatin dose daily for 8 weeks; group 5: received 20% ethanol orally for 8 weeks then received the same simvastatin dose for the next 8 weeks. Serum alanine aminotransferase, aspartate aminotransferase, total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were measured. Liver tissue malondialdehyde, reduced glutathione levels, and superoxide dismutase activity were estimated. B-cell lymphoma 2 and C/EBP homologous protein levels were evaluated by enzyme linked immunosorbent assay (ELISA). Light chain 3-II and peroxisome proliferation-activated receptor gamma messenger RNA expression was assessed by real-time polymerase chain reaction. Immunohistochemical staining was performed using anti-rat tumor necrosis factor-alpha antibody. Our results revealed that simvastatin treatment was able to ameliorate alcohol-induced liver damage; the improved biochemical data were confirmed by histopathological evaluation. Simvastatin being an autophagy inducer was able to prevent and reverse alcohol-induced liver changes via induction of autophagy, attenuation of oxidative stress, inflammation, and endoplasmic reticulum stress-induced apoptosis. Therefore, our findings suggest that treatment with simvastatin may be a useful approach in the management strategy of ALD.

Roles of extrahepatic lipolysis and the disturbance of hepatic fatty acid metabolism in TNF-α -induced hepatic steatosis

Our previous study showed that both Kupffer cell eliminator (GdCl₃) and tumor necrosis factor α (TNF-α) receptor antagonist (etanercept) could partially attenuate binge drinking-induced liver steatosis. Herein, we extended the study by directly investigating the roles of TNF-α on the hepatic fat levels in mice and in HepG2 cells, and explored the underlying mechanisms. SPF male ICR mice were exposed to TNF-α (0.166 mg/kg body weight) with or without phenylisopropyl adenosine (PIA, an anti-lipolytic drug) for 1.5, 3, 6, and 24 h. We found that TNF-α treatment resulted in hepatic triglyceride (TG) elevation at 6 h time point, which was blocked by PIA. TNF-α led to the activation of extrahepatic lipolysis demonstrated by the increase of serum free fatty acid (FFA) level, and the increased protein levels of adipose triglyceride lipase (ATGL) and phosphorylated hormone-sensitive lipase (HSL) in mice epididymal adipose tissues, but had no significant effects on the protein levels of sterol regulatory element binding protein 1c (SREBP-1c) and peroxisomal proliferator activation receptor α (PPAR-α) in mice liver. The in vitro study showed TNF-α treatment could not result in elevation of TG in HepG2 cells, although it indeed brought about a slight activation of SREBP-1c. These results support the hypothesis that TNF-α might make a small contribution to ethanol-induced fatty liver by stimulating extrahepatic lipolysis.

Targeting Nrf-2 is a promising intervention approach for the prevention of ethanol-induced liver disease

Alcoholic liver disease (ALD) remains to be a worldwide health problem. It is generally accepted that oxidative stress plays critical roles in the pathogenesis of ALD, and antioxidant therapy represents a logical strategy for the prevention and treatment of ALD. Nuclear factor erythroid-derived 2-like 2 (NFE2L2 or Nrf-2) is essential for the antioxidant responsive element (ARE)-mediated induction of endogenous antioxidant enzymes such as heme oxygenase 1 (HO-1) and glutamate-cysteine ligase [GCL, the rate-limiting enzyme in the synthesis of glutathione (GSH)]. Activation of Nrf-2 pathway by genetic manipulation or pharmacological agents has been demonstrated to provide protection against ALD, which suggests that targeting Nrf-2 may be a promising approach for the prevention and treatment of ALD. Herein, we review the relevant literature about the potential hepatoprotective roles of Nrf-2 activation against ALD.

Baccharis trimera protects against ethanol induced hepatotoxicity in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Baccharis trimera has been traditionally used in Brazil to treat liver diseases.

AIM OF THE STUDY

To evaluate the protective effect of Baccharis trimera in an ethanol induced hepatotoxicity model.

MATERIALS AND METHODS

The antioxidant capacity was evaluated in vitro by the ability to scavenged the DPPH radical, by the quantification of ROS, NO and the transcription factor Nrf2. Hepatotoxicity was induced in animals by administration of absolute ethanol for 2 days (acute) or with ethanol diluted for 28 days (chronic). The biochemical parameters of hepatic function (ALT and AST), renal function (urea and creatinine) and lipid profile (total cholesterol, triglycerides and HDL) were evaluated. In addition to antioxidant defense (SOD, catalase, glutathione), oxidative damage markers (TBARS and carbonylated protein), MMP-2 activity and liver histology.

RESULTS

Baccharis trimera promoted a decrease in ROS and NO, and at low concentrations promoted increased transcription of Nrf2. In the acute experiment it promoted increase of HDL, in the activity of SOD and GPx, besides diminishing TBARS and microesteatosis. Already in the chronic experiment B. trimera improved the hepatic and renal profile, decreased triglycerides and MMP-2 activity, in addition to diminishing microesteatosis.

CONCLUSION

We believe that B. trimera action is possibly more associated with direct neutralizing effects or inhibition of reactive species production pathways rather than the modulation of the antioxidant enzymes activity. Thus it is possible to infer that the biological effects triggered by adaptive responses are complex and multifactorial depending on the dose, the time and the compounds used.

Genetic deletion of the circadian clock transcription factor BMAL1 and chronic alcohol consumption differentially alter hepatic glycogen in mice

Multiple metabolic pathways exhibit time-of-day-dependent rhythms that are controlled by the molecular circadian clock. We have shown that chronic alcohol is capable of altering the molecular clock and diurnal oscillations in several elements of hepatic glycogen metabolism ( 19 , 44 ). Herein, we sought to determine whether genetic disruption of the hepatocyte clock differentially impacts hepatic glycogen content in chronic alcohol-fed mice. Male hepatocyte-specific BMAL1 knockout (HBK) and littermate controls were fed control or alcohol-containing diets for 5 wk to alter hepatic glycogen content. Glycogen displayed a significant diurnal rhythm in livers of control genotype mice fed the control diet. While rhythmic, alcohol significantly altered the diurnal oscillation of glycogen in livers of control genotype mice. The glycogen rhythm was mildly altered in livers of control-fed HBK mice. Importantly, glycogen content was arrhythmic in livers of alcohol-fed HBK mice. Consistent with these changes in hepatic glycogen content, we observed that some glycogen and glucose metabolism genes were differentially altered by chronic alcohol consumption in livers of HBK and littermate control mice. Diurnal rhythms in glycogen synthase (mRNA and protein) were significantly altered by alcohol feeding and clock disruption. Alcohol consumption significantly altered Gck, Glut2, and Ppp1r3g rhythms in livers of control genotype mice, with diurnal rhythms of Pklr, Glut2, Ppp1r3c, and Ppp1r3g further disrupted (dampened or arrhythmic) in livers of HBK mice. Taken together, these findings show that chronic alcohol consumption and hepatocyte clock disruption differentially influence the diurnal rhythm of glycogen and various key glycogen metabolism-related genes in the liver. NEW & NOTEWORTHY We report that circadian clock disruption exacerbates alcohol-mediated alterations in hepatic glycogen. We observed differential responsiveness in diurnal rhythms of glycogen and glycogen metabolism genes and proteins in livers of hepatocyte-specific BMAL1 knockout and littermate control mice fed alcohol. Our findings provide new insights into potential mechanisms by which alcohol alters glycogen, an important energy source for liver and other organs.

Small heterodimer partner deficiency exacerbates binge drinking‑induced liver injury via modulation of natural killer T cell and neutrophil infiltration

Binge drinking among alcohol consumers is a common occurrence, and may result in the development of numerous diseases, including liver disorders. It has previously been reported that natural killer T (NKT) cells induce alcohol‑associated liver injury by promoting neutrophil infiltration. In the present study, the role of the orphan nuclear receptor small heterodimer partner (SHP), which is encoded by the NR0B2 gene, in acute binge drinking‑induced liver injury was investigated. SHP‑knockout (KO) and wild‑type (WT) control mice were intragastrically administered single doses of alcohol. The plasma concentrations of alanine aminotransferase and aspartate aminotransferase in SHP‑KO mice following alcohol treatment were significantly increased compared with WT mice. However, results of oil red O staining and 2',7'‑dichlorodihydrofluorescein diacetate staining indicated that levels of acute binge drinking‑associated hepatic lipid accumulation and oxidative stress were not significantly different between WT and SHP‑KO alcohol‑treated mice. Notably, tumor necrosis factor‑α mRNA expression in the liver of SHP‑KO mice was significantly increased following alcohol administration, compared with WT mice. Furthermore, the mRNA expression levels of C‑C motif chemokine ligand 2, C‑X‑C motif chemokine ligand 2 and interleukin‑4, which are all potent chemoattractants of NKT cells, as well as neutrophil expression levels, were significantly increased in the livers of SHP‑KO mice compared with WT mice following alcohol administration, as determined by reverse transcription‑quantitative polymerase chain reaction and flow cytometry. Enhanced infiltration of NKT cells, determined by flow cytometry, was also demonstrated in the livers of SHP‑KO mice following alcohol administration, compared with WT mice. The results of the present study indicate that SHP may be involved in liver‑associated protective mechanisms, with regards to the attenuation of damage caused by acute binge drinking, via regulation of NKT cell and neutrophil migration to the liver. The modulation of SHP may be a novel therapeutic strategy for the treatment of acute binge drinking‑induced liver injury.

Poly(ADP-Ribose) Polymerase Inhibitor PJ34 Attenuated Hepatic Triglyceride Accumulation in Alcoholic Fatty Liver Disease in Mice

Poly(ADP-ribose) polymerase (PARP) is an NAD-consuming enzyme and its specific role in the pathogenesis of alcoholic fatty liver disease (AFLD) remains elusive. In this study, we applied PJ34 [N-(5,6-dihydro-6-oxo-2-phenanthridinyl)-2-acetamide hydrochloride] to inhibit hepatic PARP activity to examine the corresponding pathologic alteration in AFLD in mice and the underlying molecular mechanism. We found that PJ34 decreased the intracellular triglyceride (TG) content in hepatocytes. Moreover, PJ34 suppressed the gene expression of diglyceride acyltransferases DGAT1 and DGAT2 and elevated intracellular NAD⁺ levels in hepatocytes. These mechanistic observations were validated in alcohol-fed mice injected with PJ34 intraperitoneally. Our results indicate that the PJ34 injection attenuated hepatic TG accumulation in alcohol-fed mice. Furthermore, PJ34 injection lowered the gene expression of hepatic sterol regulatory element binding protein 1c, DGAT1, and DGAT2, whereas PJ34 injection augmented hepatic NAD⁺ levels in alcohol-fed mice. Finally, nicotinamide riboside supplementation alleviated hepatic TG accumulation in alcohol-fed mice. These data indicate that applying PARP-specific inhibitor PJ34 by intraperitoneal injection attenuated hepatic NAD⁺ depletion and TG accumulation in alcohol-fed mice and may be a potential candidate for use in AFLD therapy.

Lipophagy and liver disease: New perspectives to better understanding and therapy

Intracellular lipid droplets (LDs) are remarkably dynamic and complex organelles that enact regulated storage and release of lipids to fulfil their fundamental roles in energy metabolism, membrane synthesis and provision of lipid-derived signaling molecules. The recent finding that LDs can be selectively degraded by the lysosomal pathway of autophagy through a process termed lipophagy has opened up a new understanding of how lipid metabolism regulates cellular physiology and pathophysiology. Many new functions for autophagic lipid metabolism have now been defined in various diseases including liver disease. Lipophagy was originally described in hepatocytes, where it is critical for maintaining cellular energy homeostasis in obesity and metabolic syndrome. In vitro and in vivo studies have demonstrated the selective uptake of LDs by autophagosomes, and inhibition of autophagy has been shown to reduce the β-oxidation of free fatty acids due to the increased accumulation of lipids and LDs. The identification of lipophagy as a new process dedicated to cellular lipid removal has mapped autophagy as an emerging player in cellular lipid metabolism. Pharmacological or genetic modulation of lipophagy might point to possible therapeutic strategies for combating a broad range of liver diseases. This review summarizes recent work focusing on lipophagy and liver disease as well as highlighting challenges and future directions of research. On the other hand, it also offers a glimpse into different strategies that have been used in experimental models to counteract excessive pathological lipophagy in the prevention and treatment of liver disease.