Role of Oxidative Stress in Pathophysiology of Nonalcoholic Fatty Liver Disease

Combined Metabolic Activators Decrease Liver Steatosis by Activating Mitochondrial Metabolism in Hamsters Fed with a High-Fat Diet

Although the prevalence of non-alcoholic fatty liver disease (NAFLD) continues to increase, there is no effective treatment approved for this condition. We previously showed, in high-fat diet (HFD)-fed mice, that the supplementation of combined metabolic activators (CMA), including nicotinamide riboside (NAD+ precursor) and the potent glutathione precursors serine and N-acetyl-l-cysteine (NAC), significantly decreased fatty liver by promoting fat oxidation in mitochondria. Afterwards, in a one-day proof-of-concept human supplementation study, we observed that this CMA, including also L-carnitine tartrate (LCT), resulted in increased fatty acid oxidation and de novo glutathione synthesis. However, the underlying molecular mechanisms associated with supplementation of CMA have not been fully elucidated. Here, we demonstrated in hamsters that the chronic supplementation of this CMA (changing serine for betaine) at two doses significantly decreased hepatic steatosis. We further generated liver transcriptomics data and integrated these data using a liver-specific genome-scale metabolic model of liver tissue. We systemically determined the molecular changes after the supplementation of CMA and found that it activates mitochondria in the liver tissue by modulating global lipid, amino acid, antioxidant and folate metabolism. Our findings provide extra evidence about the beneficial effects of a treatment based on this CMA against NAFLD.

Supplementation with a Specific Combination of Metabolic Cofactors Ameliorates Non-Alcoholic Fatty Liver Disease, Hepatic Fibrosis, and Insulin Resistance in Mice

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) have emerged as the leading causes of chronic liver disease in the world. Obesity, insulin resistance, and dyslipidemia are multifactorial risk factors strongly associated with NAFLD/NASH. Here, a specific combination of metabolic cofactors (a multi-ingredient; MI) containing precursors of glutathione (GSH) and nicotinamide adenine dinucleotide (NAD+) (betaine, N-acetyl-cysteine, L-carnitine and nicotinamide riboside) was evaluated as effective treatment for the NAFLD/NASH pathophysiology. Six-week-old male mice were randomly divided into control diet animals and animals exposed to a high fat and high fructose/sucrose diet to induce NAFLD. After 16 weeks, diet-induced NAFLD mice were distributed into two groups, treated with the vehicle (HFHFr group) or with a combination of metabolic cofactors (MI group) for 4 additional weeks, and blood and liver were obtained from all animals for biochemical, histological, and molecular analysis. The MI treatment reduced liver steatosis, decreasing liver weight and hepatic lipid content, and liver injury, as evidenced by a pronounced decrease in serum levels of liver transaminases. Moreover, animals supplemented with the MI cocktail showed a reduction in the gene expression of some proinflammatory cytokines when compared with their HFHFr counterparts. In addition, MI supplementation was effective in decreasing hepatic fibrosis and improving insulin sensitivity, as observed by histological analysis, as well as a reduction in fibrotic gene expression (Col1α1) and improved Akt activation, respectively. Taken together, supplementation with this specific combination of metabolic cofactors ameliorates several features of NAFLD, highlighting this treatment as a potential efficient therapy against this disease in humans.

Capillin protects against non-alcoholic steatohepatitis through suppressing NLRP3 inflammasome activation and oxidative stress

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is an extreme form of non-alcoholic fatty liver disease. The present study concentrated on the role of Capillin, a polyacetylene compound isolated from Artemisia capillaris Thunb., in NASH development.

MATERIALS AND METHODS

Palmitic acid (PA) was treated with FL83B hepatocytes, and high-fat diet was given to mouse to construct the NASH model in vivo. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, flow cytometry, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were carried out to measure the viability and apoptosis of FL83B hepatocytes. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to measure the mRNA expressions of infiltration markers (Cd11c, Ccr2, and Ly6c), fibrosis genes (Tgfβ1, Col1a1, and Timp1), and alpha-smooth muscle actin (α-SMA). Western blot, immunofluorescence, and Enzyme-linked immunosorbent assay (ELISA) were implemented to examine the proteins of Caspase-3, Bcl2, Nrf2, HO-1, NLRP3, ASC, and Caspase-1, the ROS level, and oxidative stress markers (MDA, GSH-ST, SOD, and GSH-Px), and the lipid peroxidation level, respectively. Moreover, HE staining was manipulated to observe the histopathological changes in liver tissue.

RESULTS

Capillin hampered PA-mediated hepatocytes apoptosis and enhanced cell viability. Furthermore, Capillin suppressed PA-mediated oxidative stress in hepatocytes, promoted Nrf2/HO-1 expression, and repressed NLRP3-ASC-Caspase1 inflammasome. The in vivo studies indicated that Capillin vigorously improves liver fat accumulation, oxidative stress, and liver injury in NASH mice. Mechanistically, Capillin repressed NLRP3-ASC-Caspase1 inflammasome and up-regulated the Nrf2-HO-1 pathway in the liver.

CONCLUSION

Capillin ameliorates hepatocyte injury by dampening oxidative stress and repressing NLRP3 inflammasome in NASH mice.

Lipid Disorders in NAFLD and Chronic Kidney Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver dysfunction and is characterized by exaggerated lipid accumulation, inflammation and even fibrosis. It has been shown that NAFLD increases the risk of other chronic diseases, particularly chronic kidney disease (CKD). Lipid in excess could lead to liver and kidney lesions and even end-stage disease through diverse pathways. Dysregulation of lipid uptake, oxidation or de novo lipogenesis contributes to the toxic effects of ectopic lipids which promotes the development and progression of NAFLD and CKD via triggering oxidative stress, apoptosis, pro-inflammatory and profibrotic responses. Importantly, dyslipidemia and release of pro-inflammatory cytokines caused by NAFLD (specifically, nonalcoholic steatohepatitis) are considered to play important roles in the pathological progression of CKD. Growing evidence of similarities between the pathogenic mechanisms of NAFLD and those of CKD has attracted attention and urged researchers to discover their common therapeutic targets. Here, we summarize the current understanding of molecular aberrations underlying the lipid metabolism of NAFLD and CKD and clinical evidence that suggests the relevance of these pathways in humans. This review also highlights the orchestrated inter-organ cross-talk in lipid disorders, as well as therapeutic options and opportunities to counteract NAFLD and CKD.

Chromium picolinate balances the metabolic and clinical markers in nonalcoholic fatty liver disease: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is a complicated disease and is considered as a severe global health problem affecting 30% of adults worldwide. The present study aimed to evaluate changes in oxidative stress, adipokines, liver enzyme, and body composition following treatment with chromium picolinate (CrPic) among patients with NAFLD.

PARTICIPANTS AND METHODS

The current randomized, double-blind, placebo-controlled study was conducted on 46 NAFLD patients with the age range of 20-65 years. Patients were randomly classified into two groups, receiving either 400 µg CrPic tablets in two divided doses of 200 µg (23 patients) or placebo (23 patients) daily for 12 weeks. The participants' body composition and biochemical parameters were evaluated at the baseline and after 12 weeks.

RESULTS

Serum levels of liver enzymes reduced significantly only in the CrPic group (P < 0.05 for all), but not between the groups after the intervention. Besides, there were significant differences between the study groups regarding body weight and body fat mass, total antioxidant capacity, superoxide dismutase, malondialdehyde, leptin, and adiponectin post-intervention (P = 0.017, P = 0.032, P = 0.003, P = 0.023, P = 0.012, P = 0.003, and P = 0.042, respectively). However, glutathione peroxidase and resistin levels did not differ significantly between groups (P = 0.127 and P = 0.688, respectively).

DISCUSSION AND CONCLUSION

This study showed that consuming 400 µg/day of CrPic for 12 weeks in patients with NAFLD causes a significant change in leptin, adiponectin, oxidative stress (expect glutathione peroxidase), and body weight, compared to baseline. Nevertheless, it does not affect liver enzymes. Therefore, the CrPic supplementation may improve adipokines, some anthropometric indices, and oxidative stress in patients with NAFLD.

Oxidative Stress and Localization Status of Hepatocellular Transporters: Impact on Bile Secretion and Role of Signaling Pathways

Significance: Most hepatopathies are primarily or secondarily cholestatic in nature. Oxidative stress (OS) is a frequent trait among them, and impairs the machinery to generate bile by triggering endocytic internalization of hepatocellular transporters, thus causing cholestasis. This is critical, since it leads to accelerated transporter degradation, which could explain the common post-transcriptional downregulation of transporter expression in human cholestatic diseases. Recent Advances: The mechanisms involved in OS-induced hepatocellular transporter internalization are being revealed. Filamentous actin (F-actin) cytoskeleton disorganization and/or detachment of crosslinking actin proteins that afford transporter stability have been characterized as causal factors. Activation of redox-sensitive signaling pathways leading to changes in phosphorylation status of these structures is involved, including Ca²⁺-mediated activation of "classical" and "novel" protein kinase C (PKC) isoforms or redox-signaling cascades downstream of NADPH oxidase. Critical Issues: Despite the well-known occurrence of hepatocellular transporter internalization in human hepatopathies, the cholestatic implications of this phenomenon have been overlooked. Accordingly, no specific treatment has been established in the clinical practice for its prevention/reversion. Future Directions: We need to improve our knowledge on the pro-oxidant triggering factors and the multiple signaling pathways that mediate this oxidative injury in each cholestatic hepatopathy, so as to envisage tailor-made therapeutic strategies for each case. Meanwhile, administration of antioxidants or heme oxygenase-1 induction to elevate the hepatocellular levels of the endogenous scavenger bilirubin are promising alternatives that need to be re-evaluated and implemented. They may complement current treatments in cholestasis aimed to enhance transcriptional carrier expression, by providing membrane stability to the newly synthesized carriers. Antioxid. Redox Signal. 35, 808-831.

"Bioelectrical impedance analysis in managing sarcopenic obesity in NAFLD"

INTRODUCTION

Sarcopenic obesity and its association with nonalcoholic fatty liver disease (NAFLD) is under-recognized by many healthcare providers in Western medicine due to the lack of awareness and diagnostic guidelines. The result is delayed recognition and treatment, which leads to further health deterioration and increased healthcare costs. Sarcopenic obesity is characterized by the presence of increased fat mass in combination with muscle catabolism related to chronic inflammation and/or inactivity. Previous research has recommended evaluating body composition and physical function performance to adequately diagnose sarcopenic obesity. Body composition analysis can be performed by imaging applications through magnetic resonance imaging, computed tomography, and dual-energy x-ray absorptiometry. Due to the cost of each device and radiation exposure for patients as evidenced in all three modalities, bioelectrical impedance analysis offers a noninvasive approach capable of providing quick and reliable estimates of lean body and fat mass.

METHODS AND RESULTS

This review analyzes the current evidence-based literature, indicating a lower skeletal muscle mass and increased visceral adipose tissue correlation to the advancement of fibrosis in fatty liver disease.

CONCLUSION

Given the substantial promising research conducted in predominantly Asian populations regarding body tissue distribution and NAFLD, additional prospective research is needed to extend these findings in Western populations.

Hepatic NF-κB-Inducing Kinase and Inhibitor of NF-κB Kinase Subunit α Promote Liver Oxidative Stress, Ferroptosis, and Liver Injury

Drug-induced hepatotoxicity limits development of new effective medications. Drugs and numerous endogenous/exogenous agents are metabolized/detoxified by hepatocytes, during which reactive oxygen species (ROS) are generated as a by-product. ROS has broad adverse effects on liver function and integrity, including damaging hepatocyte proteins, lipids, and DNA and promoting liver inflammation and fibrosis. ROS in concert with iron overload drives ferroptosis. Hepatic nuclear factor kappa B (NF-κB)-inducing kinase (NIK) is aberrantly activated in a broad spectrum of liver disease. NIK phosphorylates and activates inhibitor of NF-κB kinase subunit alpha (IKKα), and the hepatic NIK/IKKα cascade suppresses liver regeneration. However, the NIK/IKKα pathway has not been explored in drug-induced liver injury. Here, we identify hepatic NIK as a previously unrecognized mediator for acetaminophen (APAP)-induced acute liver failure. APAP treatment increased both NIK transcription and NIK protein stability in primary hepatocytes as well as in liver in mice. Hepatocyte-specific overexpression of NIK augmented APAP-induced liver oxidative stress in mice and increased hepatocyte death and mortality in a ROS-dependent manner. Conversely, hepatocyte-specific ablation of NIK or IKKα mitigated APAP-elicited hepatotoxicity and mortality. NIK increased lipid peroxidation and cell death in APAP-stimulated primary hepatocytes. Pretreatment with antioxidants or ferroptosis inhibitors blocked NIK/APAP-induced hepatocyte death. Conclusion: We unravel a previously unrecognized NIK/IKKα/ROS/ferroptosis axis engaged in liver disease progression.

Dietary patterns and risk of non-alcoholic fatty liver disease in adults: A prospective cohort study

BACKGROUND AND AIMS

Prospective cohort studies linking dietary patterns and non-alcoholic fatty liver disease (NAFLD) are limited, especially in Asian populations. This study aimed to prospectively investigate the association between dietary patterns and risk of NAFLD in a general Chinese adult population.

METHODS

This study included a total of 17,360 participants free from NAFLD at baseline. Dietary patterns at baseline were identified with factor analysis based on responses to a validated 100-item food frequency questionnaire. NAFLD was diagnosed by abdominal ultrasound after excluding other causes related to chronic liver disease. Cox proportional regression models were used to assess the association between dietary patterns and risk of NAFLD.

RESULTS

During a median follow-up of 4.2 years, 4034 NAFLD cases were documented. Three main dietary patterns were extracted: sugar rich dietary pattern, vegetable rich dietary pattern, and animal food dietary pattern. After adjusting for age, sex, body mass index, smoking, alcohol, education, occupation, income, physical activity, total energy intake, personal and family history of disease, depressive symptoms, dietary supplement use, inflammation markers, and each other dietary pattern score, comparing the highest with the lowest quartiles of dietary pattern scores, the multivariable hazard ratios (95% confidence interval) of NAFLD were 1.11 (1.01, 1.23) for sugar rich dietary pattern, 0.96 (0.86, 1.07) for vegetable rich dietary pattern, and 1.22 (1.10, 1.36) for animal food dietary pattern. Further adjustment for waist circumference instead of body mass index provided similar results.

CONCLUSION

Dietary patterns rich in animal foods or sugar were associated with a higher risk of NAFLD among Chinese adults, whereas a vegetable rich dietary pattern was not associated.

The Protective Role of the Heme Catabolic Pathway in Hepatic Disorders

Significance: As the central metabolic organ, the liver is exposed to a variety of potentially cytotoxic, proinflammatory, profibrotic, and carcinogenic stimuli. To protect the organism from these deleterious effects, the liver has evolved a number of defense systems, which include antioxidant substrates and enzymes, anti-inflammatory tools, enzymatic biotransformation systems, and metabolic pathways. Recent Advances: One of the pivotal systems that evolved during phylogenesis was the heme catabolic pathway. Comprising the important enzymes heme oxygenase and biliverdin reductase, this complex pathway has a number of key functions including enzymatic activities, but also cell signaling, and DNA transcription. It further generates two important bile pigments, biliverdin and bilirubin, as well as the gaseous molecule carbon monoxide. These heme degradation products have potent antioxidant, immunosuppressive, and cytoprotective effects. Recent data suggest that the pathway participates in the regulation of metabolic and hormonal processes implicated in the pathogenesis of hepatic and other diseases. Critical Issues: This review discusses the impact of the heme catabolic pathway on major liver diseases, with particular focus on the involvement of cellular targeting and signaling in the pathogenesis of these conditions. Future Directions: To utilize the biological consequences of the heme catabolic pathway, several unique therapeutic strategies have been developed. Research indicates that pharmaceutical, nutraceutical, and lifestyle modifications positively affect the pathway, delivering potentially long-term clinical benefits. However, further well-designed studies are needed to confirm the clinical benefits of these approaches. Antioxid. Redox Signal. 35, 734-752.

The Mitochondrial Trigger in an Animal Model of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the leading liver chronic disease featuring hepatic steatosis. Mitochondrial β-oxidation participates in the derangement of lipid metabolism at the basis of NAFLD, and mitochondrial oxidative stress contributes to the onset of the disease. We evaluated the presence and effects of mitochondrial oxidative stress in the liver from rats fed a high-fat plus fructose (HF-F) diet inducing NAFLD. Supplementation with dehydroepiandrosterone (DHEA), a multitarget antioxidant, was tested for efficacy in delaying NAFLD. A marked mitochondrial oxidative stress was originated by all diets, as demonstrated by the decrease in Superoxide Dismutase 2 (SOD2) and Peroxiredoxin III (PrxIII) amounts. All diets induced a decrease in mitochondrial DNA content and an increase in its oxidative damage. The diets negatively affected mitochondrial biogenesis as shown by decreased peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α), mitochondrial transcription factor A (TFAM), and the COX-IV subunit from the cytochrome c oxidase complex. The reduced amounts of Beclin-1 and lipidated LC3 II form of the microtubule-associated protein 1 light chain 3 (LC3) unveiled the diet-related autophagy's decrease. The DHEA supplementation did not prevent the diet-induced changes. These results demonstrate the relevance of mitochondrial oxidative stress and the sequential dysfunction of the organelles in an obesogenic diet animal model of NAFLD.

Dietary Patterns Influence Target Gene Expression through Emerging Epigenetic Mechanisms in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) refers to the pathologic buildup of extra fat in the form of triglycerides in liver cells without excessive alcohol intake. NAFLD became the most common cause of chronic liver disease that is tightly associated with key aspects of metabolic disorders, including insulin resistance, obesity, diabetes, and metabolic syndrome. It is generally accepted that multiple mechanisms and pathways are involved in the pathogenesis of NAFLD. Heredity, sedentary lifestyle, westernized high sugar saturated fat diet, metabolic derangements, and gut microbiota, all may interact on a on genetically susceptible individual to cause the disease initiation and progression. While there is an unquestionable role for gene-diet interaction in the etiopathogenesis of NAFLD, it is increasingly apparent that epigenetic processes can orchestrate many aspects of this interaction and provide additional mechanistic insight. Exciting research demonstrated that epigenetic alterations in chromatin can influence gene expression chiefly at the transcriptional level in response to unbalanced diet, and therefore predispose an individual to NAFLD. Thus, further discoveries into molecular epigenetic mechanisms underlying the link between nutrition and aberrant hepatic gene expression can yield new insights into the pathogenesis of NAFLD, and allow innovative epigenetic-based strategies for its early prevention and targeted therapies. Herein, we outline the current knowledge of the interactive role of a high-fat high-calories diet and gene expression through DNA methylation and histone modifications on the pathogenesis of NAFLD. We also provide perspectives on the advancement of the epigenomics in the field and possible shortcomings and limitations ahead.

Oxidative stress and cardiometabolic biomarkers in patients with non-alcoholic fatty liver disease

Oxidative stress is assumed to be the underlying feature of non-alcoholic fatty liver disease (NAFLD). To our knowledge, the mutual involvement of redox status homeostasis parameters [i.e., advanced oxidation protein products (AOPP), pro-oxidant-antioxidant balance (PAB), total oxidant status (TOS), total antioxidant status (TAS) and oxidative-stress index (OSI)] and cardiometabolic biomarkers in subjects with NAFLD has not been examined yet. Accordingly, we aimed to investigate this potential relationship. A total of 122 subjects with NAFLD were compared with 56 participants without NAFLD. The diagnosis of NAFLD was confirmed by abdominal ultrasound. Anthropometric and biochemical parameters were measured. OSI, Castelli’s Risk Index I (CRI-I) and Castelli’s Risk Index II (CRI-II) were calculated. Univariate and multivariate binary logistic regression analysis were used to test the predictions of oxidative stress and cardiometabolic markers, respectively for NAFLD. Principal component analysis (PCA) was applied to explore its mutual effect on NAFLD status. Significant positive associations of CRI-I, CRI-II, high sensitivity C-reactive protein (hsCRP) and AOPP with NAFLD were found. PCA analysis extracted 3 significant factors: Oxidative stress-cardiometabolic related factor (i.e., triglycerides, AOPP, HDL-c and HbA1c)-explained 36% of variance; Pro-oxidants related factor (i.e., TOS and PAB)-explained 17% of variance; and Antioxidants related factor (i.e., TAS)-explained 15% of variance of the tested parameters. Moreover, binary logistic regression analysis revealed significant predictive ability of Oxidative stress-cardiometabolic related factor (p < 0.001) and Pro-oxidants related factor (p < 0.05) for NAFLD status. In addition to oxidative stress (i.e., determined by higher AOPP levels), dyslipidemia (i.e., determined by higher lipid indexes: CRI-I and CRI-II) and inflammation (determined by higher hsCRP) are independently related to NAFLD status. The mutual involvement of pro-oxidants (i.e., TOS and PAB), or the joint involvement of pro-oxidants (i.e., AOPP) and cardiometabolic parameters (i.e., HbA1c, triglycerides and HDL-c) can differentiate subjects with NAFLD from those individuals without this metabolic disorder. New studies are needed to validate our results in order to find the best therapeutic approach for NAFLD.

Cisd2 Preserves the Youthful Pattern of the Liver Proteome during Natural Aging of Mice

Cisd2 (CDGSH iron sulfur domain 2) is a pro-longevity gene that extends the lifespan and health span of mice, ameliorates age-associated structural damage and limits functional decline in multiple tissues. Non-alcoholic fatty liver disease (NAFLD), which plays an important role in age-related liver disorders, is the most common liver disease worldwide. However, no medicines that can be used to specifically and effectively treat NAFLD are currently approved for this disease. Our aim was to provide pathological and molecular evidence to show that Cisd2 protects the liver from age-related dysregulation of lipid metabolism and protein homeostasis. This study makes four major discoveries. Firstly, a persistently high level of Cisd2 protects the liver from age-related fat accumulation. Secondly, proteomics analysis revealed that Cisd2 ameliorates age-related dysregulation of lipid metabolism, including lipid biosynthesis and β-oxidation, in mitochondria and peroxisomes. Thirdly, Cisd2 attenuates aging-associated oxidative modifications of proteins. Finally, Cisd2 regulates intracellular protein homeostasis by maintaining the functionality of molecular chaperones and protein synthesis machinery. Our proteomics findings highlight Cisd2 as a novel molecular target for the development of therapies targeting fatty liver diseases, and these new therapies are likely to help prevent subsequent malignant progression to cirrhosis and hepatocellular carcinoma.

The effect of anthocyanins supplementation on liver enzymes among patients with metabolic disorders: A systematic review and meta-analysis of randomized clinical trials

The present study aims to summarize and quantitatively examine the available evidence on the effectiveness of anthocyanin supplementation on liver enzymes among patients with metabolic disorders, by employing a systematic review and meta-analytic approach. Online databases including PubMed/Medline, Scopus, ISI Web of Science, and Cochrane Library were searched up to June 2020 for randomized controlled trials (RCTs) that examined the effect of anthocyanin supplementation on serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among patients with metabolic disorders. To estimate the overall effect of anthocyanin supplementation, we employed the random-effects model. In total, 12 RCTs were included in the systematic review. Pooled analysis did not show any significant changes in ALT (WMD: -0.92 U/L, 95% CI: -4.19 to 2.35, p = .58; I²  = 91.3%) and AST (WMD: -1.22 U/L, 95% CI: -3.43 to 0.99, p = .28; I²  = 87.0) concentrations after supplementation with anthocyanin. The dose and duration of supplementation were the potential sources of heterogeneity among most of the trials. However, subgroup analysis showed that the effect is not statistically significant in all subgroups. Overall, in our study, anthocyanin does not have any effect on liver enzyme levels significantly. However, future high-quality studies are still needed to confirm the results.

Live Combined B. subtilis and E. faecium Alleviate Liver Inflammation, Improve Intestinal Barrier Function, and Modulate Gut Microbiota in Mice with Non-Alcoholic Fatty Liver Disease

Background

Non-alcoholic fatty liver disease (NAFLD) is a chronic, progressive liver disease with an increasing incidence rate. This study investigated the protective effects of live combined Bacillus subtilis and Enterococcus faecium (LCBE) on NAFLD, and its possible mechanisms.

Material/Methods

Five-week-old C57BL/6 mice were randomly divided into 3 groups: chow, HFD, and HFD+LCBE groups. The levels of serum biochemical markers, glucose tolerance, insulin, the inflammatory cytokines IL-1β, IL-6, and TNF-α, LPS, and histological staining were measured using commercial kits. qPCR was used to examine the mRNA expression levels of inflammatory cytokines in the liver. Western blotting was used to determine the protein levels of TLR4, NF-κB p65, PPAR-α, and CPT-1 in the liver, and occludin and Claudin1 in the intestine. The intestinal flora of the mice was analyzed by high-throughput sequencing of the V3–V4 region of 16S rDNA.

Results

LCBE significantly lowered the body weight, liver/body weight ratio, and serum glucose level, and increased the serum insulin level in NAFLD mice. In addition, LCBE treatment improved the liver function and lipid profile, decreased the levels of LPS and inflammatory cytokines, and downregulated the expression of TLR4 and NF-κB p65. Moreover, LCBE enhanced the intestinal barrier function by increasing the expression of occludin and Claudin1. Furthermore, LCBE modulated the composition of the gut microbiota by reducing the Firmicutes to Bacteroidetes ratio, and the proportion of inflammation-related and LPS-producing bacteria, thus re-arranging the structure of the gut microbiota.

Conclusions

LCBE protects against NAFLD by alleviating inflammation, restoring the intestinal barrier, and modulating gut microbiota composition.

Antioxidant Role of Kaempferol in Prevention of Hepatocellular Carcinoma

Reactive oxygen species (ROS) are noxious to cells because their increased level interacts with the body's defense mechanism. These species also cause mutations and uncontrolled cell division, resulting in oxidative stress (OS). Prolonged oxidative stress is responsible for incorrect protein folding in the endoplasmic reticulum (ER), causing a stressful condition, ER stress. These cellular stresses (oxidative stress and ER stress) are well-recognized biological factors that play a prominent role in the progression of hepatocellular carcinoma (HCC). HCC is a critical global health problem and the third leading cause of cancer-related mortality. The application of anti-oxidants from herbal sources significantly reduces oxidative stress. Kaempferol (KP) is a naturally occurring, aglycone dietary flavonoid that is present in various plants (Crocus sativus, Coccinia grandis, Euphorbia pekinensis, varieties of Aloe vera, etc.) It is capable of interacting with pleiotropic proteins of the human body. Efforts are in progress to develop KP as a potential candidate to prevent HCC with no adverse effects. This review emphasizes the molecular mechanism of KP for treating HCC, targeting oxidative stress.

Impact of dietary compositions and patterns on the prevalence of nonalcoholic fatty liver disease in Japanese men: a cross-sectional study

BACKGROUND

This study aimed to examine the impact of dietary compositions and patterns on nonalcoholic fatty liver disease (NAFLD) morbidity in Japanese men.

METHODS

We conducted a cross-sectional study of 281 individuals who underwent comprehensive medical examinations during health screening. Dietary intake was assessed using a semi-quantitative food frequency questionnaire, and factor analysis was performed to detect dietary patterns. NAFLD was diagnosed by the presence of fatty liver on abdominal ultrasonography in nondrinkers (< 30 g/day), and patients were categorized into control (n = 192) and NAFLD groups (n = 89).

RESULTS

Compared with the control group, the NAFLD group consumed fewer mushrooms. Three dietary patterns were identified, namely, a healthy pattern, a western pattern, and a snack pattern. The score of healthy pattern was negatively correlated with the risk of NAFLD. Compared with the lowest tertile of the healthy pattern, the middle tertile was associated with a lower risk of NAFLD after adjusting for age, physical activity, and smoking (odds ratio: 0.47, 95% confidence interval: 0.25-0.91). After further adjustments for body mass index, the middle tertile was associated with a lower risk of NAFLD (odds ratio: 0.46, 95% confidence interval: 0.23-0.92).

CONCLUSIONS

A healthy dietary pattern comprising frequent intake of seaweeds, vegetables, mushrooms, pulses, and potatoes and starches was associated with a lower risk of NAFLD in Japanese men. In our opinion, this healthy pattern closely resembles the Japanese Washoku diet, indicating that adherence to Washoku may help prevent NAFLD.

3,4-dihydroxytoluene, a metabolite of rutin, suppresses the progression of nonalcoholic fatty liver disease in mice by inhibiting p300 histone acetyltransferase activity

3,3',4',5,7-Pentahydroxyflavone-3-rhamnoglucoside (rutin) is a flavonoid with a wide range of pharmacological activities. Dietary rutin is hardly absorbed because the microflora in the large intestine metabolize rutin into a variety of compounds including quercetin and phenol derivatives such as 3,4-dihydroxyphenolacetic acid (DHPAA), 3,4-dihydroxytoluene (DHT), 3,4-hydroxyphenylacetic acid (HPAA) and homovanillic acid (HVA). We examined the potential of rutin and its metabolites as novel histone acetyltransferase (HAT) inhibitors. DHPAA, HPAA and DHT at the concentration of 25 μM significantly inhibited in vitro HAT activity with DHT having the strongest inhibitory activity. Furthermore, DHT was shown to be a highly efficient inhibitor of p300 HAT activity, which corresponded with its high degree of inhibition on intracellular lipid accumulation in HepG2 cells. Docking simulation revealed that DHT was bound to the p300 catalytic pocket, bromodomain. Drug affinity responsive target stability (DARTS) analysis further supported the possibility of direct binding between DHT and p300. In HepG2 cells, DHT concentration-dependently abrogated p300-histone binding and induced hypoacetylation of histone subunits H3K9, H3K36, H4K8 and H4K16, eventually leading to the downregulation of lipogenesis-related genes and attenuating lipid accumulation. In ob/ob mice, administration of DHT (10, 20 mg/kg, iv, every other day for 6 weeks) dose-dependently improved the NAFLD pathogenic features including body weight, liver mass, fat mass, lipid accumulation in the liver, and biochemical blood parameters, accompanied by the decreased mRNA expression of lipogenic genes in the liver. Our results demonstrate that DHT, a novel p300 histone acetyltransferase inhibitor, may be a potential preventive or therapeutic agent for NAFLD.

Rho-Kinase as a Therapeutic Target for Nonalcoholic Fatty Liver Diseases

Nonalcoholic fatty liver disease (NAFLD) is a major public health problem and the most common form of chronic liver disease, affecting 25% of the global population. Although NAFLD is closely linked with obesity, insulin resistance, and type 2 diabetes mellitus, knowledge on its pathogenesis remains incomplete. Emerging data have underscored the importance of Rho-kinase (Rho-associated coiled-coil-containing kinase [ROCK]) action in the maintenance of normal hepatic lipid homeostasis. In particular, pharmacological blockade of ROCK in hepatocytes or hepatic stellate cells prevents the progression of liver diseases such as NAFLD and fibrosis. Moreover, mice lacking hepatic ROCK1 are protected against obesity-induced fatty liver diseases by suppressing hepatic de novo lipogenesis. Here we review the roles of ROCK as an indispensable regulator of obesity-induced fatty liver disease and highlight the key cellular pathway governing hepatic lipid accumulation, with focus on de novo lipogenesis and its impact on therapeutic potential. Consequently, a comprehensive understanding of the metabolic milieu linking to liver dysfunction triggered by ROCK activation may help identify new targets for treating fatty liver diseases such as NAFLD.

Ferulic acid attenuates non-alcoholic steatohepatitis by reducing oxidative stress and inflammation through inhibition of the ROCK/NF-κB signaling pathways

Ferulic acid (FA) is a natural polyphenol compound existing in many plants. The purpose of this study was to investigate the effect of FA on non-alcoholic steatohepatitis (NASH) induced by high-cholesterol and high-fat diet (HCHF) and its possible mechanism. Rats were fed HCHF for 12 weeks to establish NASH model. FA improved liver coefficients and had no effect on body weight changes. FA could reduce serum alanine transferase (ALT) and aspartate transferase (AST) activities. FA attenuated the increase of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein (LDL) levels caused by NASH, improved the liver pathological damage induced by NASH, and inhibited the progression of liver fibrosis. FA prevented the production of reactive oxygen species (ROS) and the increase of malondialdehyde (MDA) levels, and attenuated the decrease in superoxide dismutase (SOD) activity. Meanwhile, FA significantly restored the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α). In addition, we also found that FA inhibited the activity of ROCK and the activation of NF-κB signaling pathway in the liver of NASH rats. Overall, FA has a hepatoprotective anti-oxidative stress and anti-inflammatory effects in NASH rats, and its mechanism may be related to the inhibition of ROCK/NF-κB signaling pathway.

Antioxidant activity of Hydroxytyrosol and Vitamin E reduces systemic inflammation in children with paediatric NAFLD

BACKGROUND

The rise in paediatric non-alcoholic fatty liver disease (NAFLD) is particularly alarming. We recently reported that Hydroxytyrosol (HXT) and Vitamin E (VitE) may improve oxidative stress, insulin resistance, and steatosis in children with biopsy-proven NAFLD.

AIM

Here, we investigated if HXT+VitE may reduce systemic inflammation in the above-mentioned patients.

METHODS

This study analysed the plasma levels of IL (interleukin)-6, IL-1β, IL-10, tumour necrosis factor (TNF)-α, 4‑hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2'deoxyguanosine (8-OHdG) in children enrolled in the HXT+VitE trial (ClinicalTrials.gov, NCT02842567).

RESULTS

Changes in markers of systemic inflammation were found in both placebo (Pla) and HXT+VitE. In particular, after four months, the levels of IL-1β and TNF-α were reduced in both groups, while IL-6 decreased, and IL-10 increased significantly only in the group treated with HXT+VitE. Children treated with HXT+VitE showed a significant decrease of 4-HNE and 8-OHdG that correlated with the improvement of triglyceride levels. Noticeably, only the 8-OHdG decrease correlated with steatosis amelioration and with the increase of IL-10 levels.

CONCLUSION

The treatment with HXT and VitE reduced the NAFLD-related systemic inflammation in children, mainly by an increase of IL-10 circulating levels that occurred in response to DNA damage recovery, ultimately improving steatosis and hypertriglyceridemia.

Analytical and Omics-Based Advances in the Study of Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a significant clinical issue, affecting 1-1.5 million patients annually, and remains a major challenge during drug development-toxicity and safety concerns are the second-highest reason for drug candidate failure. The future prevalence of DILI can be minimized by developing a greater understanding of the biological mechanisms behind DILI. Both qualitative and quantitative analytical techniques are vital to characterizing and investigating DILI. In vitro assays are capable of characterizing specific aspects of a drug's hepatotoxic nature and multiplexed assays are capable of characterizing and scoring a drug's association with DILI. However, an even deeper insight into the perturbations to biological pathways involved in the mechanisms of DILI can be gained through the use of omics-based analytical techniques: genomics, transcriptomics, proteomics, and metabolomics. These omics analytical techniques can offer qualitative and quantitative insight into genetic susceptibilities to DILI, the impact of drug treatment on gene expression, and the effect on protein and metabolite abundance. This review will discuss the analytical techniques that can be applied to characterize and investigate the biological mechanisms of DILI and potential predictive biomarkers.

Cadmium chloride induces non-alcoholic fatty liver disease in rats by stimulating miR-34a/SIRT1/FXR/p53 axis

Cadmium (Cd) is associated with non-alcoholic fatty liver disease (NAFLD). The hepatic activation of p53/miR-43a-induced suppression of SIRT1/FXR axis plays a significant role in the development of NAFLD. In this study, we have investigated CdCl₂-induced NAFLD in rats involves activation of miR34a/SIRT1/FXR axis. Adult male rats were divided into 4 groups (n-8/each) as a control, CdCl₂ (10 mg/l), CdCl₂ + miR-34a antagomir (inhibitor), and CdCl₂ + SRT1720 (a SIRT1 activator) for 8 weeks, daily. With no effect on fasting glucose and insulin levels, CdCl₂ significantly reduced rats' final body, fat pads, and liver weights, and food intake. Concomitantly, it increased the circulatory levels of liver markers (ALT, AST, and γ-GTT), increased the serum and hepatic levels of total cholesterol and triglycerides coincided with increased hepatic lipid accumulation. Besides, it increased the mRNA and protein levels of SREBP1, SREBP2, FAS, and HMGCOA reductase but reduced mRNA levels of PPARα, CPT1, and CPT2. Interestingly, CdCl₂ also increased mRNA levels of miR34 without altering mRNA levels of SIRT1 but with a significant reduction in protein levels of SIRT1. These effects were associated with increased total protein levels of p53 and acetylated protein of p53, and FXR. Of note, suppressing miR-34a with a specific anatomic or activating SIRT1 by SRT1720 completely prevented all these effects and reduced hepatic fat accumulations in the livers of rats. In conclusion, CdCl₂ induced NAFLD by increasing the transcription of miR-34a which in turn downregulates SIRT1 at the translational level.

Peroxisomal footprint in the pathogenesis of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a form of fatty liver disease where benign hepatic steatosis leads to chronic inflammation in the steatotic liver of a patient without any history of alcohol abuse. Mechanisms underlying the progression of hepatic steatosis to NASH have long been investigated. This review outlines the potential role of peroxisomal dysfunctions in exacerbating the disease in NASH. Loss of peroxisomes as well as impaired peroxisomal functions have been demonstrated to occur in inflammatory conditions including NASH. Because peroxisomes and mitochondria co-operatively perform many metabolic functions including O₂ and lipid metabolisms, a compromised peroxisomal biogenesis and function can potentially contribute to defective lipid and reactive oxygen species metabolism which in turn can lead the progression of disease in NASH. Impaired peroxisomal biogenesis and function may be due to the decreased expression of peroxisomal proliferator-activated receptor-α (PPAR-α), the major transcription factor of peroxisomal biogenesis. Recent studies indicate that the reduced expression of PPAR-α in NASH is correlated with the activation of the toll-like receptor-4 pathway (TLR-4). Further investigations are required to establish the mechanistic connection between the TLR-4 pathway and PPAR-α-dependent impaired biogenesis/function of peroxisomes in NASH.

microRNA profiles of serum exosomes derived from children with nonalcoholic fatty liver

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a chronic disease caused by excessive fat accumulation in the liver in addition to alcohol consumption and other pathological factors. The incidence of NAFLD is rapidly growing, currently affecting 25% of the world population. Exosomes are extracellular vesicles containing a variety of biological molecules, including microRNAs (miRNAs).

OBJECTIVE

To monitor the expression of exosomal microRNAs in the NAFLD.

METHODS

In this study, five nonalcoholic fatty liver patients were included in the disease group, and five simple obesity patients were included in the control group. Exosomes from NAFLD patient serum were collected, and exosomal miRNAs were extracted. Exosomes were isolated and then confirmed by electron microscopy, nanoparticle tracking analysis (NTA) and western blotting. High-throughput sequencing methods were used to determine the expression profile of exosome-derived miRNAs.

RESULTS

The sequencing results revealed that a total of 2588 miRNAs were identified. The expression of 80 miRNAs significantly differed between the NAFLD and control groups, including 30 upregulated and 50 downregulated miRNAs. miR-122-5p, miR-27a, and miR-335-5p may play an important role in NAFLD. Finally, GO and KEGG analyses were applied to explore the function of miRNA targets.

CONCLUSIONS

Collectively, this study identified some key exosomal miRNAs and pathways in NAFLD that might be used as molecular targets or diagnostic biomarkers for NAFLD.

Commentary: Novel strategies and new tools to curtail the health effects of pesticides

BACKGROUND

Flaws in the science supporting pesticide risk assessment and regulation stand in the way of progress in mitigating the human health impacts of pesticides. Critical problems include the scope of regulatory testing protocols, the near-total focus on pure active ingredients rather than formulated products, lack of publicly accessible information on co-formulants, excessive reliance on industry-supported studies coupled with reticence to incorporate published results in the risk assessment process, and failure to take advantage of new scientific opportunities and advances, e.g. biomonitoring and "omics" technologies.

RECOMMENDED ACTIONS

Problems in pesticide risk assessment are identified and linked to study design, data, and methodological shortcomings. Steps and strategies are presented that have potential to deepen scientific knowledge of pesticide toxicity, exposures, and risks. We propose four solutions: (1) End near-sole reliance in regulatory decision-making on industry-supported studies by supporting and relying more heavily on independent science, especially for core toxicology studies. The cost of conducting core toxicology studies at labs not affiliated with or funded directly by pesticide registrants should be covered via fees paid by manufacturers to public agencies. (2) Regulators should place more weight on mechanistic data and low-dose studies within the range of contemporary exposures. (3) Regulators, public health agencies, and funders should increase the share of exposure-assessment resources that produce direct measures of concentrations in bodily fluids and tissues. Human biomonitoring is vital in order to quickly identify rising exposures among vulnerable populations including applicators, pregnant women, and children. (4) Scientific tools across disciplines can accelerate progress in risk assessments if integrated more effectively. New genetic and metabolomic markers of adverse health impacts and heritable epigenetic impacts are emerging and should be included more routinely in risk assessment to effectively prevent disease.

CONCLUSIONS

Preventing adverse public health outcomes triggered or made worse by exposure to pesticides will require changes in policy and risk assessment procedures, more science free of industry influence, and innovative strategies that blend traditional methods with new tools and mechanistic insights.

Intervention by picroside II on FFAs induced lipid accumulation and lipotoxicity in HepG2 cells

Background

Accumulation of free fatty acids (FFAs) in hepatocytes is a hallmark of liver dysfunction and non-alcoholic fatty liver disease (NAFLD). Excessive deposition of FFAs alters lipid metabolism pathways increasing the oxidative stress and mitochondrial dysfunction. Attenuating hepatic lipid accumulation, oxidative stress, and improving mitochondrial function could provide potential targets in preventing progression of non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH). Earlier studies with Picrorhiza kurroa extract have shown reduction in hepatic damage and fatty acid infiltration in several experimental models and also clinically in viral hepatitis. Thus, the effect of P. kurroa's phytoactive, picroside II, needed mechanistic investigation in appropriate in vitro liver cell model.

Objective(s)

To study the effect of picroside II on FFAs accumulation, oxidative stress and mitochondrial function with silibinin as a positive control in in vitro NAFLD model.

Materials and methods

HepG2 cells were incubated with FFAs-1000μM in presence and absence of Picroside II-10 μM for 20 hours.

Results

HepG2 cells incubated with FFAs-1000μM lead to increased lipid accumulation. Picroside II-10μM attenuated FFAs-induced lipid accumulation (33%), loss of mitochondrial membrane potential (ΔΨm), ATP depletion, and production of reactive oxygen species (ROS). A concomitant increase in cytochrome C at transcription and protein levels was observed. An increase in expression of MnSOD, catalase, and higher levels of tGSH and GSH:GSSG ratios underlie the ROS salvaging activity of picroside II.

Conclusion

Picroside II significantly attenuated FFAs-induced-lipotoxicity. The reduction in ROS, increased antioxidant enzymes, and improvement in mitochondrial function underlie the mechanisms of action of picroside II. These findings suggest a need to develop an investigational drug profile of picroside II for NAFLD as a therapeutic strategy. This could be evaluated through the fast-track path of reverse pharmacology.

PPARs as Metabolic Sensors and Therapeutic Targets in Liver Diseases

Carbohydrates and lipids are two components of the diet that provide the necessary energy to carry out various physiological processes to help maintain homeostasis in the body. However, when the metabolism of both biomolecules is altered, development of various liver diseases takes place; such as metabolic-associated fatty liver diseases (MAFLD), hepatitis B and C virus infections, alcoholic liver disease (ALD), and in more severe cases, hepatocelular carcinoma (HCC). On the other hand, PPARs are a family of ligand-dependent transcription factors with an important role in the regulation of metabolic processes to hepatic level as well as in other organs. After interaction with specific ligands, PPARs are translocated to the nucleus, undergoing structural changes to regulate gene transcription involved in lipid metabolism, adipogenesis, inflammation and metabolic homeostasis. This review aims to provide updated data about PPARs’ critical role in liver metabolic regulation, and their involvement triggering the genesis of several liver diseases. Information is provided about their molecular characteristics, cell signal pathways, and the main pharmacological therapies that modulate their function, currently engaged in the clinic scenario, or in pharmacological development.

Regulation of hepatic fibrosis by carcinoembryonic antigen-related cell adhesion molecule 1

OBJECTIVE

NAFLD is a complex disease marked by cellular abnormalities leading to NASH. NAFLD patients manifest low hepatic levels of CEACAM1, a promoter of insulin clearance. Consistently, Cc1^-/- null mice displayed spontaneous hyperinsulinemia/insulin resistance and steatohepatitis. Liver-specific reconstitution of Ceacam1 reversed these metabolic anomalies in 8-month-old Cc1^-/-xliver+ mice fed a regular chow diet. The current study examined whether it would also reverse progressive hepatic fibrosis in mice fed a high-fat (HF) diet.

METHODS

3-Month-old mice were fed a high-fat diet for 3-5 months, and metabolic and histopathological analysis were conducted to evaluate their NASH phenotype.

RESULTS

Reconstituting CEACAM1 to Cc1^-/- livers curbed diet-induced liver dysfunction and NASH, including macrovesicular steatosis, lobular inflammation, apoptosis, oxidative stress, and chicken-wire bridging fibrosis. Persistence of hepatic fibrosis in HF-fed Cc1^-/- treated with nicotinic acid demonstrated a limited role for lipolysis and adipokine release in hepatic fibrosis caused by Ceacam1 deletion.

CONCLUSIONS

Restored metabolic and histopathological phenotype of HF-fed Cc1^{-/-xliver+xliver+} assigned a critical role for hepatic CEACAM1 in preventing NAFLD/NASH including progressive hepatic fibrosis.

Neutral sphingomyelinase-2 and cardiometabolic diseases

Sphingolipids, in particular ceramides, play vital role in pathophysiological processes linked to metabolic syndrome, with implications in the development of insulin resistance, pancreatic ß-cell dysfunction, type 2 diabetes, atherosclerosis, inflammation, nonalcoholic steatohepatitis, and cancer. Ceramides are produced by the hydrolysis of sphingomyelin, catalyzed by different sphingomyelinases, including neutral sphingomyelinase 2 (nSMase2), whose dysregulation appears to underlie many of the inflammation-related pathologies. In this review, we discuss the current knowledge on the biochemistry of nSMase2 and ceramide production and its regulation by inflammatory cytokines, with particular reference to cardiometabolic diseases. nSMase2 contribution to pathogenic processes appears to involve cyclical feed-forward interaction with proinflammatory cytokines, such as TNF-α and IL-1ß, which activate nSMase2 and the production of ceramides, that in turn triggers the synthesis and release of inflammatory cytokines. We elaborate these pathogenic interactions at the molecular level and discuss the potential therapeutic benefits of inhibiting nSMase2 against inflammation-driven cardiometabolic diseases.

Oxidative stress in obesity-associated hepatocellular carcinoma: sources, signaling and therapeutic challenges

Obesity affects more than 650 million individuals worldwide and is a well-established risk factor for the development of hepatocellular carcinoma (HCC). Oxidative stress can be considered as a bona fide tumor promoter, contributing to the initiation and progression of liver cancer. Indeed, one of the key events involved in HCC progression is excessive levels of reactive oxygen species (ROS) resulting from the fatty acid influx and chronic inflammation. This review provides insights into the different intracellular sources of obesity-induced ROS and molecular mechanisms responsible for hepatic tumorigenesis. In addition, we highlight recent findings pointing to the role of the dysregulated activity of BCL-2 proteins and protein tyrosine phosphatases (PTPs) in the generation of hepatic oxidative stress and ROS-mediated dysfunctional signaling, respectively. Finally, we discuss the potential and challenges of novel nanotechnology strategies to prevent ROS formation in obesity-associated HCC.

Zonisamide Therapy Reduces Metabolic Consequences and Diminishes Nonalcoholic Fatty Liver Disease in Patients with Epilepsy

Antiepileptic drugs that can reduce aberrant metabolism are beneficial for patients. Zonisamide (ZNS) is a chemical with antiepileptic and antioxidant activities. Here, we evaluate the efficacy of ZNS therapy on reducing obesity and decreasing risks of vascular diseases and hepatic steatosis. Clinical and metabolic indicators including body weight, body mass index (BMI), serum lipid profiles, glycated hemoglobin (HbA1c), homocysteine, and an inflammatory marker, high-sensitivity C-reactive protein (hs-CRP), were assessed at baseline and at the end of 12 and 24 weeks of treatment. Nonalcoholic fatty liver disease was evaluated using the hepatic steatosis index (HSI). A body weight reduction of ≥5% was observed in 24.6% and 32.8% of patients after 12 and 24 weeks of ZNS treatment, respectively. After adjusting for age, sex, time, and the corresponding dependent variable at baseline, the generalized estimating equation analysis revealed that the body weight, BMI, serum levels of HbA1c, triglycerides, hs-CRP, and the index for HSI were significantly declined. These results suggest that ZNS provides benefits in patients with obesity and metabolic syndrome at high vascular risk.

CYP2E1 in Alcoholic and Non-Alcoholic Liver Injury. Roles of ROS, Reactive Intermediates and Lipid Overload

CYP2E1 is one of the fifty-seven cytochrome P450 genes in the human genome and is highly conserved. CYP2E1 is a unique P450 enzyme because its heme iron is constitutively in the high spin state, allowing direct reduction of, e.g., dioxygen, causing the formation of a variety of reactive oxygen species and reduction of xenobiotics to toxic products. The CYP2E1 enzyme has been the focus of scientific interest due to (i) its important endogenous function in liver homeostasis, (ii) its ability to activate procarcinogens and to convert certain drugs, e.g., paracetamol and anesthetics, to cytotoxic end products, (iii) its unique ability to effectively reduce dioxygen to radical species causing liver injury, (iv) its capability to reduce compounds, often generating radical intermediates of direct toxic or indirect immunotoxic properties and (v) its contribution to the development of alcoholic liver disease, steatosis and NASH. In this overview, we present the discovery of the enzyme and studies in humans, 3D liver systems and genetically modified mice to disclose its function and clinical relevance. Induction of the CYP2E1 enzyme either by alcohol or high-fat diet leads to increased severity of liver pathology and likelihood to develop ALD and NASH, with subsequent influence on the occurrence of hepatocellular cancer. Thus, fat-dependent induction of the enzyme might provide a link between steatosis and fibrosis in the liver. We conclude that CYP2E1 has many important physiological functions and is a key enzyme for hepatic carcinogenesis, drug toxicity and liver disease.

Dimethyl fumarate reduces oxidative stress, inflammation and fat deposition by modulation of Nrf2, SREBP-1c and NF-κB signaling in HFD fed mice

Nonalcoholic fatty liver disease (NAFLD) occurs due to lipid metabolic disorders, which is associated with hepatic oxidative stress and inflammation. There is no definitive drug treatment for this disease. Accordingly, the present study aimed to evaluate the effects of dimethyl fumarate (DMF) as one of the superior effective drugs that induces a transcription factor of nuclear factor erythroid 2-related factor 2 (Nrf2) on development of NAFLD in mice. The metabolic disturbance in High-fat diet (HFD)-treated animals was associated with hyperlipidemia, increased activity levels of hepatic enzymes in serum, hyperglycemia, hyperinsulinemia, oxidative stress and inflammation. DMF supplementation had anti-inflammatory, antioxidant, anti-lipogenic and molecular compatibility effects induced by HFD in mice. In comparison to the HFD group, the DMF therapy could significantly suppress the sterol regulatory element binding protein-1 c (SREBP-1c) gene and protein levels, as well as upregulate the Nrf2 gene and protein levels. Additionally, the anti-inflammatory activity was observed for the DMF by inhibiting the nuclear factor kappa B (NF-κB) level. DMF reduces the development of NAFLD induced by HFD in mice through the modulation of transcription factors Nrf2, SREBP-1c and NF-κB. Thus, DMF can be considered as an effective candidate in the treatment of human NAFLD.

Antioxidant and Antisteatotic Activities of Fucoidan Fractions from Marine and Terrestrial Sources

Fucoidan is a fucose-rich sulfated polysaccharide typically found in the cell wall of marine algae but also recently isolated from terrestrial sources. Due to a variety of biological activities, including antioxidant properties, fucoidan exhibits an attractive therapeutic potential against a wide array of metabolic diseases associated with oxidative stress. We used FTIR, 1H NMR and 13C NMR spectroscopy to investigate the structural features of a fucoidan fraction extracted from the brown alga Cystoseira compressa (CYS). The antioxidant potential of CYS was measured by DPPH, ABTS and FRAP assays, which revealed a radical scavenging capacity that was confirmed in in vitro cellular models of hepatic and endothelial cells. The same antioxidant effects were observed for another fucoidan fraction previously identified in the terrestrial tree Eucalyptus globulus (EUC). Moreover, in hepatic cells, CYS and EUC exhibited a significant antisteatotic action, being able to reduce intracellular triglyceride content through the regulation of key genes of hepatic lipid metabolism. EUC exerted stronger antioxidant and antisteatotic effects as compared to CYS, suggesting that both marine and terrestrial sources should be considered for fucoidan extraction and therapeutic applications.

Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests

The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of β-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. "Dynamic" liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope 13C. Hepatocellular metabolization of the substrate will generate 13CO2, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of 13CO2 are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. 13C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, 13C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. 13C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of 13C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.

Supplementation of cumin seed powder prevents oxidative stress, hyperlipidemia and non-alcoholic fatty liver in high fat diet fed rats

The present investigation was an attempt to evaluate the hypoglycemic, lipid-lowering, antioxidant and hepatoprotective effects of cumin (Cuminum cyminum family: Apiaceae) supplementation in high fat (HF) diet fed rats. Male Wistar rats were divided into four groups, such as control, control+ cumin, HF and HF+ cumin. Oral glucose tolerance test, plasma lipids, oxidative stress parameters, antioxidant enzymes activities, and liver dysfunction marker enzyme activities were evaluated. Additionally, histological staining of liver tissue was performed to evaluate the inflammatory cells infiltration, iron deposition and fibrosis. The current investigation demonstrated that 1% (w/w) supplementation of cumin powder significantly reduced HF diet-induced glucose intolerance, epididymal and mesenteric fat wet weights and lipid parameters like triglycerides, total cholesterol and low-density lipoproteins. Oxidative stress-related biomarkers including thiobarbituric acid reactive substances (TBARS), nitric oxide (NO) and advanced oxidation protein product (APOP) were also reduced by cumin supplementation. Moreover, HF-diet increased the activity of hepatic biomarker enzymes such as alanine transaminase (ALT) and alkaline phosphatase (ALP) activities which were significantly reduced by cumin powder supplementation. On the other hand, cumin powder supplementation was able to restore the reduced glutathione level with parallel augmentation of the antioxidant enzymes activities such as superoxide dismutase (SOD) and catalase in liver of HF diet-fed rats. Additionally, histological assessments confirmed that cumin powder supplementation also normalized the fat droplet deposition and inflammatory cells infiltration in the liver of HF diet-fed rats. This study suggests that cumin powder supplementation ameliorates dyslipidemia, oxidative stress and hepatic damage in HF diet-fed rats.

Caveolin-1 Alleviates Acetaminophen-Induced Fat Accumulation in Non-Alcoholic Fatty Liver Disease by Enhancing Hepatic Antioxidant Ability via Activating AMPK Pathway

Non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for acute liver injury caused by overuse of acetaminophen (APAP). Caveolin-1 (CAV1), a regulator of hepatic energy metabolism and oxidative stress, was found to have a protective effect against NAFLD in our previous study. However, it remains unclear whether CAV1 has a protective effect against APAP-induced hepatotoxicity in NAFLD. The aim of this study was to determine whether CAV1 inhibits oxidative stress through the AMPK/Nrf2/HO-1 pathway to protect the liver from fat accumulation exacerbated by APAP in NAFLD. In this study, seven-week-old C57BL/6 male mice (18–20 g) were raised under similar conditions for in vivo experiment. In vitro, L02 cells were treated with A/O (alcohol and oleic acid mixture) for 48 h, and APAP was added at 24 h for further incubation. The results showed that the protein expression of the AMPK/Nrf2 pathway was enhanced after CAV1 upregulation. The effects of CAV1 on fat accumulation, ROS, and the AMPK/Nrf2 anti-oxidative pathway were reduced after the application of CAV1-siRNA. Finally, treatment with compound C (an AMPK inhibitor) prevented CAV1 plasmid-mediated alleviation of oxidative stress and fat accumulation and reduced the protein level of Nrf2 in the nucleus, demonstrating that the AMPK/Nrf2/HO-1 pathway was involved in the protective effect of CAV1. These results indicate that CAV1 exerted a protective effect against APAP-aggravated lipid deposition and hepatic injury in NAFLD by inhibiting oxidative stress. Therefore, the upregulation of CAV1 might have clinical benefits in reducing APAP-aggravated hepatotoxicity in NAFLD.

Green Tea and Epigallocatechin Gallate (EGCG) for the Management of Nonalcoholic Fatty Liver Diseases (NAFLD): Insights into the Role of Oxidative Stress and Antioxidant Mechanism

Nonalcoholic fatty liver diseases (NAFLD) represent a set of liver disorders progressing from steatosis to steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma, which induce huge burden to human health. Many pathophysiological factors are considered to influence NAFLD in a parallel pattern, involving insulin resistance, oxidative stress, lipotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory cascades, fibrogenic reaction, etc. However, the underlying mechanisms, including those that induce NAFLD development, have not been fully understood. Specifically, oxidative stress, mainly mediated by excessive accumulation of reactive oxygen species, has participated in the multiple NAFLD-related signaling by serving as an accelerator. Ameliorating oxidative stress and maintaining redox homeostasis may be a promising approach for the management of NAFLD. Green tea is one of the most important dietary resources of natural antioxidants, above which epigallocatechin gallate (EGCG) notably contributes to its antioxidative action. Accumulative evidence from randomized clinical trials, systematic reviews, and meta-analysis has revealed the beneficial functions of green tea and EGCG in preventing and managing NAFLD, with acceptable safety in the patients. Abundant animal and cellular studies have demonstrated that green tea and EGCG may protect against NAFLD initiation and development by alleviating oxidative stress and the related metabolism dysfunction, inflammation, fibrosis, and tumorigenesis. The targeted signaling pathways may include, but are not limited to, NRF2, AMPK, SIRT1, NF-κB, TLR4/MYD88, TGF-β/SMAD, and PI3K/Akt/FoxO1, etc. In this review, we thoroughly discuss the oxidative stress-related mechanisms involved in NAFLD development, as well as summarize the protective effects and underlying mechanisms of green tea and EGCG against NAFLD.

Exposure to Plasma From Non-alcoholic Fatty Liver Disease Patients Affects Hepatocyte Viability, Generates Mitochondrial Dysfunction, and Modulates Pathways Involved in Fat Accumulation and Inflammation

Changes of lipidic storage, oxidative stress and mitochondrial dysfunction may be involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Although the knowledge of intracellular pathways has vastly expanded in recent years, the role and mechanisms of circulating triggering factor(s) are debated. Thus, we tested the hypothesis that factors circulating in the blood of NAFLD patients may influence processes underlying the disease. Huh7.5 cells/primary human hepatocytes were exposed to plasma from 12 NAFLD patients and 12 healthy subjects and specific assays were performed to examine viability, H₂O₂ and mitochondrial reactive oxygen species (ROS) release, mitochondrial membrane potential and triglycerides content. The involvement of NLRP3 inflammasome and of signaling related to peroxisome-proliferator-activating-ligand-receptor-γ (PPARγ), sterol-regulatory-element-binding-protein-1c (SREBP-1c), nuclear-factor-kappa-light-chain-enhancer of activated B cells (NF-kB), and NADPH oxidase 2 (NOX2) was evaluated by repeating the experiments in the presence of NLRP3 inflammasome blocker, MCC950, and through Western blot. The results obtained shown that plasma of NAFLD patients was able to reduce cell viability and mitochondrial membrane potential by about 48 and 24% (p < 0.05), and to increase H₂O₂, mitochondrial ROS, and triglycerides content by about 42, 19, and 16% (p < 0.05), respectively. An increased expression of SREBP-1c, PPARγ, NF-kB and NOX2 of about 51, 121, 63, and 46%, respectively, was observed (p < 0.05), as well. Those effects were reduced by the use of MCC950. Thus, in hepatocytes, exposure to plasma from NAFLD patients induces a NAFLD-like phenotype by interference with NLRP3-inflammasome pathways and the activation of intracellular signaling related to SREBP-1c, PPARγ, NF-kB and NOX2.

Links between metabolic syndrome and metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a chronic condition characterized by hepatic fat accumulation combined with underlying metabolic dysregulation. Having evolved from the previous term of nonalcoholic fatty liver disease (NAFLD), the term MAFLD more closely implicates the presence of overweight/obesity, type 2 diabetes, or metabolic dysregulation as essential pathogenic factors, leading to better identification of individuals with this metabolic liver disease. Low-grade inflammation, increased oxidative stress, mitochondrial dysfunction, and intestinal dysbiosis are also involved in its pathogenesis. MAFLD is not only associated with liver-related complications, but also with adverse cardiometabolic outcomes. Further studies are needed to assess whether the newly proposed definition of MAFLD is more accurate than the NAFLD in predicting the adverse liver-related and extrahepatic outcomes.

Alleviative effects of total flavones of Glycyrrhiza uralensis Fisch on oxidative stress and lipid metabolism disorder induced by high-fat diet in intestines of Tilapia (Oreochromis niloticus)

Total flavones of Glycyrrhiza uralensis Fisch (GTF) are main components of Glycyrrhiza uralensis Fisch, which have anti-oxidation and lipid-lowering effects. However, its protective effects on the intestinal tissue of tilapia (Oreochromis niloticus) are unknown. The aims of the study were to evaluate the protective effects of GTF on the intestinal tissue of tilapia after high-fat diet (HFD) feeding. Tilapia (initial weight 30 ± 1 g) received diets containing four doses of GTF (0.05, 0.1, 0.5, and 1.0 g/kg diet) for 90 days. The intestinal tissues were collected to determine biochemical parameter, gene expression and protein level. The results showed that the HFD reduced antioxidant indexes and increased the fat level, lipid oxidation products in the intestinal tissue relative to the control. Adding GTF to the HFD resulted in an increase of antioxidant indexes, fat level and lipid oxidation products decreased after 60, 90 days. In the HFD group, mRNA level of fatty acid transport protein 1 (FATP1) was increased at 60 day and then decreased at 90 day. The mRNA levels of fatty acid binding protein 1 (FABP1) and sterol regulatory element binding protein 1c (SREBP 1c) were significantly increased at 60 or 90 day after HFD feeding. The mRNA levels of acetate coenzyme A carboxylase (ACCA) peroxisome proliferator-activated receptor γ (PPAR-γ) and PPAR-α were decreased significantly at 30, 60 and/or 90 days after HFD feeding. Western blotting results also showed that nuclear factor (NF)-κβ C-Rel (NF-κβ C-Rel) and mitogen-activated protein kinase 8 (MAPK8) protein expression in intestinal tissue increased after consumption of the HFD. However, adding GTF to the HFD reversed the changes of genes related to fatty acid synthesis and metabolism, and the level of NF-κβ c-Rel and MAPK8 at different degrees. Overall, these results indicated that GTF promoted decomposition and metabolism of fatty acids in intestinal tissue, alleviated oxidative stress damage caused by the HFD, and had certain protective effects on the intestinal tissue of tilapia.

Exploring the Changes of Peroxisomal Polarity in the Liver of Mice with Nonalcoholic Fatty Liver Disease

Peroxisome proliferator-activated receptor alpha (PPAR-a) is a crucial nuclear transcription regulator of lipid metabolism, which is closely associated with the initiation and development of nonalcoholic fatty liver disease (NAFLD). Because PPAR-a can directly decide the level of peroxisomal metabolic enzymes, its changes might directly cause variations in peroxisomal polarity. Therefore, we developed a new two-photon fluorescence imaging probe, PX-P, in which the triphenylamine and cyanide moieties can real-time sense peroxisomal polarity changes. Using PX-P, we observed a prominent decrease in the peroxisomal polarity in the liver of mice with NAFLD for the first time. More importantly, we discovered that intracellular excessive peroxynitrite (ONOO^-) and hydrogen peroxide (H₂O₂) underwent nitrification and oxidation, respectively, with various sites of PPAR-a. Interestingly, the key site of PPAR-a was nitrated by a low concentration of ONOO^- rather than being oxidized by the high level of H₂O₂. These drastically reduced the activity of PPAR-a, accelerating the occurrence of NAFLD. Moreover, through activating PPARs with pioglitazone, peroxisomal polarity markedly increased compared with that of NAFLD. Altogether, our work presents a new approach for the early diagnosis of NAFLD and identifies potential therapeutic targets.

β-patchoulene protects against non-alcoholic steatohepatitis via interrupting the vicious circle among oxidative stress, histanoxia and lipid accumulation in rats

Non-alcoholic steatohepatitis (NASH), an extreme progressive subtype of metabolic associated fatty liver disease, is well characterized by hepatic steatosis, injury and inflammation. It causes irreversible hepatic damage and there are no approved interventions for it. β-PAE, a representatively pharmacological active substance isolated from Pogostemon cablin, has been indicated to alleviate hepatic steatosis and injury through modulating lipid metabolism in rats with simple steatosis. However, its protection against NASH remains unclear. Here, this study explored the potential effect of β-PAE against high-fat diet-induced NASH in rats. The results displayed that β-PAE significantly reduced the gains of body weight and epididymal adipose tissue, liver index and attenuated liver histological damages in NASH rats. It also markedly alleviated hepatic inflammation by inhibiting NLRP3 inflammasome activation. In NASH, the active NLRP3 inflammasome is caused by hepatic lipid abnormal accumulation-induced oxidative stress. Excessive oxidative stress results in hepatic histanoxia, which exacerbates lipid metabolism disorders by elevating CD36 to suppress AMPK signalling pathways. Moreover, the lipid accumulation led by lipid metabolism dysfunction intensifies oxidative stress. A vicious circle is formed among oxidative stress, histanoxia and lipid accumulation, eventually, but β-PAE effectively interrupted it. Interestingly, soluble CD36 (sCD36) was tightly associated not only with hepatic steatosis and injury but also with inflammation. Collectively, β-PAE exerted a positive effect against NASH by interrupting the vicious circle among oxidative stress, histanoxia and lipid accumulation, and sCD36 may be a promising non-invasive tool for NASH diagnosis.

Buchholzia coriacea seed (wonderful kolanut) alleviates insulin resistance, steatosis, inflammation and oxidative stress in high fat diet model of fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a hepatic condition with multiple pathological features and it currently has no specific treatment or approved drug. Wonderful kolanut widely consumed fresh or cooked has been applied in the treatment of numerous diseases in folk medicine. In this study, we evaluate the therapeutic potentials of hydroethanolic extract of defatted Buccholzia coriacea seeds (HEBCS) in NAFLD model. HEBCS was subjected to liquid chromatography - mass spectrometry, and 30 male BALB/c mice (28 ± 2 g) were allocated to three (3) experimental groups (n = 10/group). Mice in group I were fed chow diet (CD); those in group II, high fat diet (HFD) and group III, HFD and 250 mg/kg HEBCS p.o. daily for six weeks. HEBCS alleviates HFD-induced insulin resistance and high plasma insulin and glucose levels. It further alleviates hepatic steatosis, and alters plasma lipid profile. HEBCS also protected against HFD-induced inflammation, oxidative stress and hepatocellular damage. In conclusion, HEBCS alleviated NAFLD in mice via suppression of insulin resistance, hyperlipidemia, inflammation and oxidative stress. PRACTICAL APPLICATIONS: Bioactive polyphenols and alkaloids were identified in hydroethanolic extract of defatted Buccholzia coriacea seeds (HEBCS). This study projects HEBCS as a potential therapeutic agent in the treatment of NAFLD. NAFLD is a multi-factorial condition and therefore, HEBCS is promising considering its multiple-target actions in the current model of NAFLD. HEBCS alleviates insulin resistance, metabolic dysfunction, steatosis, and inflammation in this model. There is a need to further investigate HEBCS in other models of NAFLD as a lead to future use in clinical studies.

Association of hepatic steatosis derived from ultrasound and quantitative MRI with prediabetes in the general population

The aim of our study was to investigate the association of hepatic steatosis derived from quantitative ultrasound and magnetic resonance imaging (MRI) with prediabetes in a large population-based study conducted in Northeast Germany. Hepatic steatosis was assessed through transabdominal ultrasound and quantitative MRI. For analysis we included 1622 subjects with MRI who participated in an oral glucose tolerance test and reported no known type 2 diabetes mellitus (T2DM). We classified participants as proposed by the American Diabetes Association: isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (i-IGT), combined IFG and IGT (IFG + IGT), and undiagnosed T2DM. Regression models were adjusted for age, sex body mass index and alcohol consumption. We observed positive associations of hepatic steatosis with glycated hemoglobin, fasting glucose and insulin, 2-h glucose and insulin, as well as homeostasis model assessment-insulin resistance index. Similarly, individuals having hepatic steatosis as defined by MRI had a higher relative risk ratio (RR) to be in the prediabetes groups i-IFG (RR = 1.6; 95% confidence interval (CI) 1.2; 2.2), i-IGT (RR = 3.3, 95% CI 2.0; 5.6) and IFG + IGT (RR = 2.5, 95% CI 1.6; 3.9) or to have undiagnosed T2DM (RR = 4.8, 95% CI 2.6; 9.0). All associations were attenuated when defining hepatic steatosis by ultrasound. Hepatic steatosis is associated with prediabetes and undiagnosed T2DM in the general population. Quantitative liver MRI revealed stronger associations with prediabetes and undiagnosed T2DM compared to ultrasound, which indicates the higher sensitivity and specificity of MRI to determine hepatic steatosis.

Ethyl Acetate Fraction of Amomum villosum var. xanthioides Attenuates Hepatic Endoplasmic Reticulum Stress-Induced Non-Alcoholic Steatohepatitis via Improvement of Antioxidant Capacities

Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic steatohepatitis (NASH), affects 25% of the global population. Despite the prevalence of NAFLD worldwide, effective therapeutics are currently lacking. Amomum villosum var. xanthioides (Wall. ex Baker) T.L.Wu & S.J.Chen (AX) is a medicinal herb traditionally used for treating digestive tract disorders in countries across Asia. We aimed to examine the pharmacological effects of the ethyl acetate fraction of AX (AXEF) against tunicamycin (TM)-induced ER stress in a NASH mouse model using C57/BL6J male mice. Following TM injections (2 mg/kg), the mice were orally administrated AXEF (12.5, 25, or 50 mg/kg), silymarin (50 mg/kg), or distilled water daily for 5 days, and the outcomes for fatty liver, inflammation, and oxidative stress were measured in serum or liver tissue levels. AXEF drastically attenuated hepatic ER stress-induced NASH as indicated by decreases in lipid droplet accumulations, serum liver enzymes, hepatic inflammations, and cell death signals in the hepatic tissue and/or serum levels. Interestingly, AXEF showed potent antioxidant effects by quenching reactive oxidative stress and its final product lipid peroxide in the hepatic tissue, specifically an increase in metallothionein (MT). To confirm the underlying actions of AXEF, we observed that AXEF increases MT1 gene promoter activities in the physiological levels. Collectively, AXEF showed antioxidant properties on TM-induced ER stress in a NASH mice model through the improvement of MTs.

Enzyme-Treated Zizania latifolia Extract Protects against Alcohol-Induced Liver Injury by Regulating the NRF2 Pathway

Binge drinking patterns easily produce a state of oxidative stress that disturbs liver function. Eventually, this leads to alcoholic liver disease. A safe and effective therapy for alcoholic liver disease remains elusive. Enzyme-treated Z. latifolia extract (ETZL) was studied as a potential agent for treating alcohol-induced liver disease. In addition, its underlying mechanisms were elucidated. In the binge model, ETZL was pretreated with alcohol (5 g/kg) three times at 12-h intervals. Our results showed that ETZL pretreatment decreased the serum levels of ALT, AST, ALP, and TG. ETZL treatment appeared to prevent an increase in hepatic TG and MDA levels, and there was a decrease in total GSH following alcohol treatment. Histopathological examination showed that lipid droplets were significantly reduced in the ETZL group compared to the control group. ETZL also exhibited radical scavenging activity. It significantly reduced t-BHP-induced cytotoxicity and the production of reactive oxygen species (ROS) in HepG2 cells. ETZL also enhanced NRF2 nuclear translocation and increased expression of the downstream target genes HO-1, NQO1, and GCLC as an antioxidant defense. Finally, ETZL treatment significantly reduced cell death. Our study suggests that ETZL ameliorates binge ethanol-induced liver injury by upregulating the antioxidant defense mechanism.