Reduced Glutathione suppresses Oxidative Stress in Nonalcoholic Fatty Liver Disease

Oxidative stress and inflammation in hemodialysis: a comparison of patients with or without advanced nonalcoholic fatty liver disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease are global public health issues associated with high morbidity and mortality. Both diseases are also interlinked. Little is known about the meaning of NAFLD in hemodialysis (HD) patients. Therefore, the aim of our study was to investigate the difference in oxidative stress and inflammation in HD patients with or without advanced NAFLD. Seventy-seven HD patients were included (65.14 ± 12.34 years, 59.2% male) and divided according to abdominal ultrasound and two-dimensional shear wave elastography (2D-SWE) measurements into two groups: 1) no NAFLD or no advanced NAFLD (2D-SWE <9 kPa) and 2) advanced NAFLD (2D-SWE ≥9 kPa). Medical history data and blood results were collected. HD patients with advanced NAFLD had significantly higher levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG; p = 0.025), tumor necrosis factor-alpha (TNF-α; p = 0.023), and intercellular adhesion molecule 1 (ICAM-1; p = 0.015) in comparison to HD patients without advanced NAFLD. Interleukin 6 (IL-6) was higher in the advanced NAFLD group, but the difference was of borderline significance (p = 0.054). There was no significant difference in high-sensitivity C-reactive protein (hs-CRP), and vascular cell adhesion molecule 1 (VCAM-1) between groups. In binary logistic regression analysis, advanced NAFLD was significantly associated with 8-OHdG and ICAM-1. In conclusion, higher oxidative stress and inflammation levels are present in HD patients with advanced NAFLD.

A Literature Review of Glutathione Therapy in Ameliorating Hepatic Dysfunction in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a global cause of liver dysfunction. This spectrum of hepatic disorders can progress to severe conditions, such as non-alcoholic steatohepatitis (NASH) and cirrhosis, due to oxidative stress and sustained cellular injury. With limited pharmacological options, glutathione (GSH), a key antioxidant, has shown promising potential in reducing oxidative stress, maintaining redox balance, and improving liver function. This literature review examines studies from 2014-2024 exploring GSH therapy in NAFLD patients. Eligible studies assessed GSH as the primary intervention for NAFLD in human subjects, reporting outcomes such as liver function or oxidative stress markers. Randomized clinical trials (RCTs) were eligible, while combination therapy studies were included if GSH's effect could be isolated. Exclusions applied to non-NAFLD studies, animal/in vitro models, and non-GSH antioxidant interventions. Analysis of three studies (totaling 109 participants) demonstrated consistent improvements in alanine transaminase (ALT) levels and reductions in oxidative stress markers like 8-hydroxy-2-deoxyguanosine (8-OHdG). However, small sample sizes and inconsistent protocols limit generalizability. Further large-scale RCTs are required to confirm GSH's efficacy, determine optimal dosing, and assess long-term effects. This literature review highlights GSH's potential as a novel NAFLD therapeutic strategy while emphasizing the need for further studies to refine its clinical application.

Gut Microbiota Predicts Treatment Response to Empagliflozin Among MASLD Patients Without Diabetes Mellitus

BACKGROUND AND AIM

We aimed to investigate whether gut microbiota could predict the treatment response to pharmacological agents among metabolic dysfunction-associated steatotic liver disease (MASLD) patients without diabetes mellitus (DM), as data are lacking.

METHODS

We prospectively followed up non-diabetic MASLD patients who used empagliflozin. Clinical, anthropometric, laboratory assessments and magnetic resonance imaging-proton density fat fraction (MRI-PDFF) were performed from baseline to week 52 (EOT). Baseline stool samples were collected, and shotgun DNA metagenomic sequencing was performed to profile microbiome. The primary outcome was treatment response to empagliflozin at EOT, defined as MRI-PDFF decline ≥ 30% at EOT from baseline. Linear discriminant analysis [LDA] effect size was used to identify putative bacterial species. Multivariable logistic regression was used to derive adjusted odds ratio (aOR) of outcome with bacterial species by adjusting for clinical factors.

RESULTS

Twenty-two (48.9%) of 45 patients (median age: 56.9 years [IQR: 51.0-63.2]; male: 23 [51.1%]) achieved treatment response at EOT. There was difference in alpha diversity (Shannon index: p < 0.001; Simpson index: p = 0.001) and beta diversity (p = 0.048) in baseline microbiome between treatment response and non-response groups. Faecalibacterium prausnitzii (log10LDAscore = 4.27), Lachnospira pectinoschiza (log10LDAscore = 3.99), Anaerostipes hadrus (log10LDAscore = 3.98), Roseburia faecis (log10LDAscore = 3.97), Roseburia inulinivorans (log10LDAscore = 3.58) and Agathobaculum butyriciproducens (log10LDAscore = 2.77) were enriched in the treatment response group. L. pectinoschiza (aOR: 34.1; p = 0.015), A. hadrus (aOR:35.0; p = 0.032) and A. butyriciproducens (aOR:22.3; p = 0.023) independently predicted treatment response but not clinical factors. These three species collectively predicted treatment response with AUROC of 0.89 (95% CI: 0.80-0.99).

CONCLUSIONS

Certain gut bacterial species, particularly the combination of A. hadrus, L. pectinoschiza and A. butyriciproducens, may predict treatment response to empagliflozin in MAFLD patients without DM.

Glutathione and Selenium Supplementation Attenuates Liver Injury in Diethylnitrosamine-Induced Hepatocarcinogenic Mice by Enhancing Glutathione-Related Antioxidant Capacities

Excess oxidative stress and inadequate antioxidant capacities are critical features in the development of hepatocellular carcinoma. This study aimed to determine whether supplementation with glutathione (GSH) and/or selenium (Se), as antioxidants, attenuates diethylnitrosamine (DEN)-induced hepatocarcinogenesis in mice. C57BL/6J male mice were randomly assigned to control, DEN, DEN + GSH, DEN + Se, and DEN + GSH + Se groups for 20 weeks. Daily supplementation with GSH and/or Se commenced in the first experimental week and continued throughout the study. DEN was administered in weeks 2-9 and 16-19 of the experimental period. DEN administration induced significant pathological alterations of hepatic foci, evidenced by elevated levels of liver function, accompanied by high malondialdehyde (MDA) levels; low GSH levels; and glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) activities. Supplementation with GSH and Se significantly ameliorated liver pathological changes, reducing liver function and MDA levels while increasing GSH levels and GPx, GR, and GST activities. Notably, combined supplementation with GSH and Se more effectively increased the GSH/glutathione disulfide ratio and GPx activity than individual supplementation. Supplementation with GSH and Se attenuated liver injury in DEN-induced hepatocarcinogenic mice by enhancing GSH and its related antioxidant capacities, thereby mitigating oxidative damage.

Discovery of genomic loci for liver health and steatosis reveals overlap with glutathione redox genetics

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver condition in the United States, encompassing a wide spectrum of liver pathologies including steatosis, steatohepatitis, fibrosis, and cirrhosis. Despite its high prevalence, there are no medications currently approved by the Food and Drug Administration for the treatment of NAFLD. Recent work has suggested that NAFLD has a strong genetic component and identifying causative genes will improve our understanding of the molecular mechanisms contributing to NAFLD and yield targets for future therapeutic investigations. Oxidative stress is known to play an important role in NAFLD pathogenesis, yet the underlying mechanisms accounting for disturbances in redox status are not entirely understood. To better understand the relationship between the glutathione redox system and signs of NAFLD in a genetically-diverse population, we measured liver weight, serum biomarkers aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and graded liver pathology in a large cohort of Diversity Outbred mice. We compared hepatic endpoints to those of the glutathione redox system previously measured in the livers and kidneys of the same mice, and we screened for statistical and genetic associations using the R/qtl2 software. We discovered several novel genetic loci associated with markers of liver health, including loci that were associated with both liver steatosis and glutathione redox status. Candidate genes within each locus point to possible new mechanisms underlying the complex relationship between NAFLD and the glutathione redox system, which could have translational implications for future studies targeting NAFLD pathology.

Slc7a11 stimulates glutathione synthesis to preserve fatty acid metabolism in primary hepatocytes

Primary hepatocytes are widely used as a tool for studying metabolic function and regulation in the liver. However, the metabolic properties of primary hepatocytes are gradually lost after isolation. Here, we illustrated that fatty acid metabolism is the major compromised metabolic process in isolated primary hepatocytes, along with drastically decreased GSH and ROS content, while lipid peroxidation is increased. Gain- and loss-of-function studies revealed that Slc7a11 expression is critical in maintaining fatty acid metabolism and facilitating hormone-induced fatty acid metabolic events, which is synergistic with dexamethasone treatment. Intriguingly, Slc7a11 expression and dexamethasone treatment cooperatively upregulated AKT and AMPK signaling and mitochondrial complex expression in primary hepatocytes. Furthermore, direct treatment with reduced GSH or inhibition of ferroptosis is sufficient to drive protective effects on fatty acid metabolism in primary hepatocytes. Our results demonstrate that Slc7a11 expression in isolated primary hepatocytes induces GSH production, which protects against ferroptosis, to increase fatty acid metabolic gene expression, AKT and AMPK signaling and mitochondrial function in synergy with dexamethasone treatment, thereby efficiently preserving primary hepatocyte metabolic signatures, thus providing a promising approach to better reserve primary hepatocyte metabolic activities after isolation to potentially improve the understanding of liver biological functions from studies using primary hepatocytes.

A review of experimental and clinical studies on the therapeutic effects of pomegranate (Punica granatum) on non-alcoholic fatty liver disease: Focus on oxidative stress and inflammation

Non-alcoholic fatty liver disease (NAFLD) is frequently linked to metabolic disorders and is prevalent in obese and diabetic patients. The pathophysiology of NAFLD involves multiple factors, including insulin resistance (IR), oxidative stress (OS), inflammation, and genetic predisposition. Recently, there has been an emphasis on the use of herbal remedies with many people around the world resorting to phytonutrients or nutraceuticals for treatment of numerous health challenges in various national healthcare settings. Pomegranate (Punica granatum) parts, such as juice, peel, seed and flower, have high polyphenol content and is well known for its antioxidant capabilities. Pomegranate polyphenols, such as hydrolyzable tannins, anthocyanins, and flavonoids, have high antioxidant capabilities that can help lower the OS and inflammation associated with NAFLD. The study aimed to investigate whether pomegranate parts could attenuate OS, inflammation, and other risk factors associated with NAFLD, and ultimately prevent the development of the disease. The findings of this study revealed that: 1. pomegranate juice contains hypoglycemic qualities that can assist manage blood sugar levels, which is vital for avoiding and treating NAFLD. 2. Polyphenols from pomegranate flowers increase paraoxonase 1 (PON1) mRNA and protein levels in the liver, which can help protect liver enzymes and prevent NAFLD. 3. Punicalagin (PU) is one of the major ellagitannins found in pomegranate, and PU-enriched pomegranate extract (PE) has been shown to inhibit HFD-induced hyperlipidemia and hepatic lipid deposition in rats. 4. Pomegranate fruit consumption, which is high in antioxidants, can decrease the activity of AST and ALT (markers of liver damage), lower TNF-α (a marker of inflammation), and improve overall antioxidant capacity in NAFLD patients. Overall, the polyphenols in pomegranate extracts have antioxidant, anti-inflammatory, hypoglycemic, and protective effects on liver enzymes, which can help prevent and manage NAFLD effects on liver enzymes, which can help prevent and manage NAFLD.

Ophiopogonin D ameliorates non‑alcoholic fatty liver disease in high‑fat diet‑induced obese mice by improving lipid metabolism, oxidative stress and inflammatory response

Lipid metabolic disorders, oxidative stress and inflammation in the liver are key steps in the progression of non-alcoholic fatty liver disease (NAFLD). Ophiopogonin D (OP-D), the main active ingredient of Ophiopogon japonicus, exhibits several pharmacological activities such as antioxidant and anti-inflammatory activities. Therefore, the current study aimed to explore the role of OP-D in NAFLD in a high-fat diet (HFD)-induced obesity mouse model. To investigate the effect of OP-D on NAFLD in vivo, a NAFLD mouse model was established following feeding mice with HFD, then the mice were randomly treated with HFD or HFD + OP-D for 4 weeks. Subsequently, primary mouse hepatocytes were isolated, and enzyme-linked immunosorbent assay, reverse transcription-quantitative PCR western blotting and immunofluorescence analysis were used for assessment to explore the direct effect of OP-D in vitro. The results of the present study indicated that OP-D could ameliorate NAFLD in HFD-induced obese mice by regulating lipid metabolism and antioxidant and anti-inflammatory responses. Additionally, OP-D treatment decreased lipogenesis and inflammation levels in vitro, suggesting that the NF-κB signaling pathway may be involved in the beneficial effects of OP-D on NAFLD.

Glycerol as a precursor for hepatic de novo glutathione synthesis in human liver

BACKGROUND

Glycerol is a substrate for gluconeogenesis and fatty acid esterification in the liver, processes which are upregulated in obesity and may contribute to excess fat accumulation. Glycine and glutamate, in addition to cysteine, are components of glutathione, the major antioxidant in the liver. In principle, glycerol could be incorporated into glutathione via the TCA cycle or 3-phosphoglycerate, but it is unknown whether glycerol contributes to hepatic de novo glutathione biosynthesis.

METHODS

Glycerol metabolism to hepatic metabolic products including glutathione was examined in the liver from adolescents undergoing bariatric surgery. Participants received oral [U-13C3]glycerol (50 mg/kg) prior to surgery and liver tissue (0.2-0.7g) was obtained during surgery. Glutathione, amino acids, and other water-soluble metabolites were extracted from the liver tissue and isotopomers were quantified with nuclear magnetic resonance spectroscopy.

RESULTS

Data were collected from 8 participants (2 male, 6 female; age 17.1 years [range 14-19]; BMI 47.4 kg/m2 [range 41.3-63.3]). The concentrations of free glutamate, cysteine, and glycine were similar among participants, and so were the fractions of 13C-labeled glutamate and glycine derived from [U-13C3]glycerol. The signals from all component amino acids of glutathione - glutamate, cysteine and glycine - were strong and analyzed to obtain the relative concentrations of the antioxidant in the liver. The signals from glutathione containing [13C2]glycine or [13C2]glutamate derived from the [U-13C3]glycerol drink were readily detected, and 13C-labelling patterns in the moieties were consistent with the patterns in corresponding free amino acids from the de novo glutathione synthesis pathway. The newly synthesized glutathione with [U-13C3]glycerol trended to be lower in obese adolescents with liver pathology.

CONCLUSIONS

This is the first report of glycerol incorporation into glutathione through glycine or glutamate metabolism in human liver. This could represent a compensatory mechanism to increase glutathione in the setting of excess glycerol delivery to the liver.

Bean Leaves Ameliorate Lipotoxicity in Fatty Liver Disease

Bioactive compounds in plant-based food have protective effects against metabolic alterations, including non-alcoholic fatty liver disease (NAFLD). Bean leaves are widely cultivated in the world and are a source of dietary fiber and polyphenols. High fat/high fructose diet animal models promote deleterious effects in adipose and non-adipose tissues (lipotoxicity), leading to obesity and its comorbidities. Short-term supplementation of bean leaves exhibited anti-diabetic, anti-hyperlipidemic, and anti-obesity effects in high-fat/high-fructose diet animal models. This study aimed to evaluate the effect of bean leaves supplementation in the prevention of lipotoxicity in NAFLD and contribute to elucidating the possible mechanism involved for a longer period of time. During thirteen weeks, male Wistar rats (n = 9/group) were fed with: (1) S: Rodent Laboratory Chow 5001^® (RLC); (2) SBL: 90% RLC+ 10% dry bean leaves; (3) H: high-fat/high-fructose diet; (4) HBL: H+ 10% of dry bean leaves. Overall, a HBL diet enhanced impaired glucose tolerance and ameliorated obesity, risk factors in NAFLD development. Additionally, bean leaves exerted antioxidant (↑serum GSH) and anti-inflammatory (↓mRNA TNFα in the liver) effects, prevented hepatic fat accumulation by enhanced ↑mRNA PPARα (β oxidation), and enhanced lipid peroxidation (↓liver MDA). These findings suggest that bean leaves ameliorated hepatic lipotoxicity derived from the consumption of a deleterious diet.

Metabolomics-based strategy to assess drug hepatotoxicity and uncover the mechanisms of hepatotoxicity involved

Toxicity studies, among them hepatotoxicity, are key throughout preclinical stages of drug development to minimise undesired toxic effects that might eventually appear in the course of the clinical use of the new drug. Understanding the mechanism of injury of hepatotoxins is essential to efficiently anticipate their potential risk of toxicity in humans. The use of in vitro models and particularly cultured hepatocytes represents an easy and robust alternative to animal drug hepatotoxicity testing for predicting human risk. Here, we envisage an innovative strategy to identify potential hepatotoxic drugs, quantify the magnitude of the alterations caused, and uncover the mechanisms of toxicity. This strategy is based on the comparative analysis of metabolome changes induced by hepatotoxic and non-hepatotoxic compounds on HepG2 cells, assessed by untargeted mass spectrometry. As a training set, we used 25 hepatotoxic and 4 non-hepatotoxic compounds and incubated HepG2 cells for 24 h at a low and a high concentration (IC10 and IC50) to identify mechanism-related and cytotoxicity related metabolomic biomarkers and to elaborate prediction models accounting for global hepatotoxicity and mechanisms-related toxicity. Thereafter, a second set of 69 chemicals with known predominant mechanisms of toxicity and 18 non-hepatotoxic compounds were analysed at 1, 10, 100 and 1000 µM concentrations from which and based on the magnitude of the alterations caused as compared with non-toxic compounds, we defined a "toxicity index" for each compound. In addition, we extracted from the metabolome data the characteristic signatures for each mechanism of hepatotoxicity. The integration of all this information allowed us to identify specific metabolic patterns and, based on the occurrence of that specific metabolome changes, the models predicted the likeliness of a compound to behave as hepatotoxic and to act through a given toxicity mechanism (i.e., oxidative stress, mitochondrial disruption, apoptosis and steatosis) for each compound and concentration.

Dysregulated Liver Metabolism and Polycystic Ovarian Syndrome

A significant fraction of couples around the world suffer from polycystic ovarian syndrome (PCOS), a disease defined by the characteristics of enhanced androgen synthesis in ovarian theca cells, hyperandrogenemia, and ovarian dysfunction in women. Most of the clinically observable symptoms and altered blood biomarker levels in the patients indicate metabolic dysregulation and adaptive changes as the key underlying mechanisms. Since the liver is the metabolic hub of the body and is involved in steroid-hormonal detoxification, pathological changes in the liver may contribute to female endocrine disruption, potentially through the liver-to-ovary axis. Of particular interest are hyperglycemic challenges and the consequent changes in liver-secretory protein(s) and insulin sensitivity affecting the maturation of ovarian follicles, potentially leading to female infertility. The purpose of this review is to provide insight into emerging metabolic mechanisms underlying PCOS as the primary culprit, which promote its incidence and aggravation. Additionally, this review aims to summarize medications and new potential therapeutic approaches for the disease.

The Effect of Bioactive Aliment Compounds and Micronutrients on Non-Alcoholic Fatty Liver Disease

In the current review, we focused on identifying aliment compounds and micronutrients, as well as addressed promising bioactive nutrients that may interfere with NAFLD advance and ultimately affect this disease progress. In this regard, we targeted: 1. Potential bioactive nutrients that may interfere with NAFLD, specifically dark chocolate, cocoa butter, and peanut butter which may be involved in decreasing cholesterol concentrations. 2. The role of sweeteners used in coffee and other frequent beverages; in this sense, stevia has proven to be adequate for improving carbohydrate metabolism, liver steatosis, and liver fibrosis. 3. Additional compounds were shown to exert a beneficial action on NAFLD, namely glutathione, soy lecithin, silymarin, Aquamin, and cannabinoids which were shown to lower the serum concentration of triglycerides. 4. The effects of micronutrients, especially vitamins, on NAFLD. Even if most studies demonstrate the beneficial role of vitamins in this pathology, there are exceptions. 5. We provide information regarding the modulation of the activity of some enzymes related to NAFLD and their effect on this disease. We conclude that NAFLD can be prevented or improved by different factors through their involvement in the signaling, genetic, and biochemical pathways that underlie NAFLD. Therefore, exposing this vast knowledge to the public is particularly important.

Glutathione: Pharmacological aspects and implications for clinical use in non-alcoholic fatty liver disease

Glutathione is a tripeptide synthesized at cytosolic level, that exists in cells in a reduced form (thiol-reduced-GSH-) and in an oxidized form (disulfide-oxidized). The antioxidant function of GSH has led to speculation about its therapeutic role in numerous chronic diseases characterized by altered redox balance and reduced GSH levels, including, for instance, neurodegenerative disorders, cancer, and chronic liver diseases. Among these latter, non-alcoholic fatty liver disease (NAFLD), characterized by lipid accumulation in hepatocytes, in the absence of alcohol abuse or other steatogenic factors, is one of the most prevalent. The umbrella term NAFLD includes the pure liver fat accumulation, the so-called hepatic steatosis or non-alcoholic fatty liver, and the progressive form with inflammation, also known as non-alcoholic steatohepatitis, which is related to the increase in oxidative stress and reactive oxygen species, eventually leading to liver fibrosis. Although the pathogenetic role of oxidative stress in these diseases is well established, there is still limited evidence on the therapeutic role of GSH in such conditions. Hence, the aim of this review is to depict the current molecular and pharmacological knowledge on glutathione, focusing on the available studies related to its therapeutic activity in NAFLD.

Ferroptosis plays a novel role in nonalcoholic steatohepatitis pathogenesis

Ferroptosis relies on iron, and ferroptotic cell death is triggered when the balance of the oxidation-reduction system is disrupted by excessive lipid peroxide accumulation. A close relationship between ferroptosis and nonalcoholic steatohepatitis (NASH) is formed by phospholipid peroxidation substrates, bioactive iron, and reactive oxygen species (ROS) neutralization systems. Recent studies into ferroptosis during NASH development might reveal NASH pathogenesis and drug targets. Our review summarizes NASH pathogenesis from the perspective of ferroptosis mechanisms. Further, we discuss the relationship between mitochondrial dysfunction, ferroptosis, and NASH. Finally, potential pharmacological therapies directed to ferroptosis in NASH are hypothesized.

The Synergic Effect of a Nutraceutical Supplementation Associated to a Mediterranean Hypocaloric Diet in a Population of Overweight/Obese Adults with NAFLD

Overweight/obesity is often associated with a non-alcoholic fatty liver disease (NAFLD). The study aim was to investigate the effects of a nutraceutical supplementation associated to a Mediterranean-hypocaloric-diet (MHD) on ultrasound-liver-steatosis (ULS) grade improvement in overweight/obese patients with NAFLD. A total of 68 subjects (BMI ≥ 25 kg/m2) with NAFLD were recruited, randomized into 2 groups and treated for 3 months: the Nutraceutical group was treated with MHD plus nutraceutical supplementation (Vitamin E, L-glutathione, silymarin and hepato-active compounds); the Control-group only with a MHD. Anthropometric measurements, body composition, biochemical parameters and Hepatic steatosis index (HSI) were evaluated at baseline and after 3 months; patients with HSI >36 underwent a liver ultrasound to determine liver steatosis grade (3 severe, 2 moderate, 1 mild). In all patients, a significant improvement in nutritional and biochemical parameters was observed after treatment. After treatment, the nutraceutical group showed a significant improvement in hepatic steatosis, either according to ULS-grade (11.1% and 5.6% of patients with mild and moderate liver steatosis, respectively, showed a complete NAFLD regression; 33.3% and 22.2% of patients with moderate and severe liver steatosis, respectively showed a regression to mild liver steatosis), or according to HSI (49.3 ± 10.1 vs. 43.3 ± 9.0, p = 0.01), suggesting that a healthy diet is still the best choice, although the use of specific supplements can enhance the efficacy of dietary intervention in overweight/obese patients with NAFLD.

Glucose Increases Hepatic Mitochondrial Antioxidant Enzyme Activities in Insulin Resistant Rats Following Chronic Angiotensin Receptor Blockade

Non-alcoholic fatty liver disease (NAFLD) affects up to 20% of the world’s population. Overactivation of the angiotensin receptor type 1 (AT1) contributes to metabolic dysfunction and increased oxidant production, which are associated with NAFLD and impaired hepatic lipid metabolism. Nuclear factor erythroid-2-related factor 2 (Nrf2) regulates the expression of antioxidant phase II genes by binding to the antioxidant response element (ARE); however, the mechanisms by which AT1 contributes to this pathway during the progression of NAFLD remain unresolved. To investigate hepatic Nrf2 response to a hyperglycemic challenge, we studied three groups of rats (male, 10-weeks-old): (1) untreated, lean Long Evans Tokushima Otsuka (LETO), (2) untreated, obese Otsuka Long Evans Tokushima Fatty (OLETF), and (3) OLETF + angiotensin receptor blocker (OLETF + ARB; 10 mg olmesartan/kg/d × 6 weeks). Livers were collected after overnight fasting (T0; baseline), and 1 h and 2 h post-oral glucose load. At baseline, chronic AT1 blockade increased nuclear Nrf2 content, reduced expression of glutamate-cysteine ligase catalytic (GCLC) subunit, glutathione peroxidase 1 (GPx1), and superoxide dismutase 2 (SOD2), mitochondrial catalase activity, and hepatic 4-hydroxy-2-nonenal (4-HNE) content. The expression of hepatic interleukin-1 beta (IL-1β) and collagen type IV, which are associated with liver fibrosis, were decreased with AT1 blockade. Glucose increased Nrf2 translocation in OLETF but was reduced in ARB, suggesting that glucose induces the need for antioxidant defense that is ameliorated with ARB. These results suggest that overactivation of AT1 promotes oxidant damage by suppressing Nrf2 and contributing to hepatic fibrosis associated with NAFLD development.

Livogrit Prevents Methionine-Cystine Deficiency Induced Nonalcoholic Steatohepatitis by Modulation of Steatosis and Oxidative Stress in Human Hepatocyte-Derived Spheroid and in Primary Rat Hepatocytes

The prevalence of nonalcoholic steatohepatitis (NASH), characterized by fatty liver, oxidative injury, and inflammation, has considerably increased in the recent years. Due to the complexity of NASH pathogenesis, compounds which can target different mechanisms and stages of NASH development are required. A robust screening model with translational capability is also required to develop therapies targeting NASH. In this study, we used HepG2 spheroids and rat primary hepatocytes to evaluate the potency of Livogrit, a tri-herbal Ayurvedic prescription medicine, as a hepatoprotective agent. NASH was developed in the cells via methionine and cystine-deficient cell culture media. Livogrit at concentration of 30 µg/mL was able to prevent NASH development by decreasing lipid accumulation, ROS production, AST release, NFκB activation and increasing lipolysis, GSH (reduced glutathione), and mitochondrial membrane potential. This study suggests that Livogrit might reduce the lipotoxicity-mediated ROS generation and subsequent production of inflammatory mediators as evident from the increased gene expression of FXR, FGF21, CHOP, CXCL5, and their normalization due to Livogrit treatment. Taken together, Livogrit showed the potential as a multimodal therapeutic formulation capable of attenuating the development of NASH. Our study highlights the potential of Livogrit as a hepatoprotective agent with translational possibilities.

Oxidative stress in obesity and insulin resistance

Since obesity is one of the main factors in the development of insulin resistance (IR) and is also associated with increased oxidative stress (OxS) rate, this study aims to review the published literature to collate and provide a comprehensive summary of the studies related to the status of the OxS in the pathogenesis of obesity and related IR. OxS represents an imbalance between the production of reactive oxygen and nitrogen species (RONS) and the capacity of the antioxidant defense system (AOS) to neutralize RONS. A steady-state of RONS level is maintained through endogenous enzymatic and non-enzymatic AOS components. Three crucial enzymes, which suppress the formation of free radicals, are superoxide dismutases, catalases, and glutathione peroxidases. The second line of AOS includes non-enzymatic components such as vitamins C and E, coenzyme Q, and glutathione which neutralizes free radicals by donating electrons to RONS. Emerging evidence suggests that high RONS levels contribute to the progression of OxS in obesity by activating inflammatory pathways and thus leading to the development of pathological states, including IR. In addition, decreased level of AOS components in obesity increases the susceptibility to oxidative tissue damage and further progression of its comorbidities. Increased OxS in accumulated adipose tissue should be an imperative target for developing new therapies in obesity-related IR.

Association of UCP3 Polymorphisms with Nonalcoholic Steatohepatitis and Metabolic Syndrome in Nonalcoholic Fatty Liver Disease Brazilian Patients

Background: We investigated the possible association of uncoupling protein 3 gene (UCP3) single nucleotide polymorphisms (SNPs) with nonalcoholic steatohepatitis (NASH) and metabolic syndrome (MetS) in nonalcoholic fatty liver disease (NAFLD) Brazilian patients. Methods: UCP3 SNPs rs1726745, rs3781907, and rs11235972 were genotyped in 158 biopsy-proven NAFLD Brazilian patients. Statistics was performed with JMP, R, and SHEsis softwares. Results: The TT genotype of rs1726745 was associated with less occurrence of MetS (P = 0.006) and with lower body mass index (BMI) in the entire NAFLD sample (P = 0.01) and in the NASH group (P = 0.02). The rs1726745-T was associated with lower values of AST (P = 0.001), ALT (P = 0.0002), triglycerides (P = 0.01), and total cholesterol (P = 0.02) in the entire NAFLD sample. Between groups, there were lower values of aminotransferases strictly in individuals with NASH (AST, P = 0.002; ALT, P = 0.0007) and with MetS (AST, P = 0.002; ALT, P = 0.001). The rs3781907-G was associated with lower GGT elevation values in the entire NAFLD sample (P = 0.002), in the NASH group (P = 0.004), and with MetS group (P = 0.003) and with protection for advanced fibrosis (P = 0.01). The rs11235972-A was associated with lower GGT values in the entire NAFLD sample (P = 0.006) and in the NASH group (P = 0.01) and with MetS group (P = 0.005), with fibrosis absence (P = 0.01) and protection for advanced fibrosis (P = 0.01). The TAA haplotype was protective for NASH (P = 0.002), and TGG haplotype was protective for MetS (P = 0.01). Conclusion: UCP3 gene variants were associated with protection against NASH and MetS, in addition to lower values of liver enzymes, lipid profile, BMI and, lesser fibrosis severity in the studied population.

Dairy protein intake is inversely related to development of non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is closely related to metabolic dysfunction, including insulin resistance, obesity, and metabolic syndrome. Dairy protein, rich in casein and whey protein, could help to reduce metabolic diseases. Therefore, we investigated the relationship between dairy protein intake and incident NAFLD.

METHODS

We analyzed data for 5171 adults aged 40-69 years from the Korean Genome and Epidemiology Study.(KoGES) Participants were separated as men, women aged ≥50 years, and women aged <50 years and then divided into tertiles based on dairy protein intake. NAFLD was defined as NAFLD liver fat score >-0.640. Scores were calculated as 1.18 × metabolic syndrome (Yes: 1, No: 0) + 0.45 × diabetes mellitus (Yes: 2, No: 0) + 0.15 × serum insulin +0.04 × AST - 0.94 × (AST/ALT) - 2.89. Cox proportional hazards spline curves were drawn to visualize dose-response relationships between dairy protein intake and incident NAFLD. Multiple Cox hazard regression analysis was conducted to examine associations between dairy protein intake and incident NAFLD.

RESULTS

The Cox proportional hazards spline curves revealed a negative linear relationship between dairy protein intake and incident NAFLD. The cumulative incidence of NAFLD significantly decreased with increasing tertiles of dairy protein intake in men and women aged ≥50 years. After adjusting for confounding factors, the hazard ratios and 95% confidence intervals for NAFLD in the middle and highest tertiles, compared to the lowest tertile, were 0.80 (0.67-0.96) and 0.71 (0.57-0.88) in men, 0.89 (0.72-1.09) and 0.72 (0.56-0.92) in women aged ≥50 years, and 1.01 (0.80-1.27) and 0.91 (0.67-1.24) in women aged <50 years, respectively.

CONCLUSIONS

We found that higher dairy protein intake was significantly and inversely associated with the risk of incident NAFLD in men and women aged ≥50 years. Consumption of milk and other dairy products could help prevent the development of NAFLD.

Quantitative trait mapping in Diversity Outbred mice identifies novel genomic regions associated with the hepatic glutathione redox system

The tripeptide glutathione (GSH) is instrumental to antioxidant protection and xenobiotic metabolism, and the ratio of its reduced and oxidized forms (GSH/GSSG) indicates the cellular redox environment and maintains key aspects of cellular signaling. Disruptions in GSH levels and GSH/GSSG have long been tied to various chronic diseases, and many studies have examined whether variant alleles in genes responsible for GSH synthesis and metabolism are associated with increased disease risk. However, past studies have been limited to established, canonical GSH genes, though emerging evidence suggests that novel loci and genes influence the GSH redox system in specific tissues. The present study marks the most comprehensive effort to date to directly identify genetic loci associated with the GSH redox system. We employed the Diversity Outbred (DO) mouse population, a model of human genetics, and measured GSH and the essential redox cofactor NADPH in liver, the organ with the highest levels of GSH in the body. Under normal physiological conditions, we observed substantial variation in hepatic GSH and NADPH levels and their redox balances, and discovered a novel, significant quantitative trait locus (QTL) on murine chromosome 16 underlying GSH/GSSG; bioinformatics analyses revealed Socs1 to be the most likely candidate gene. We also discovered novel QTL associated with hepatic NADP⁺ levels and NADP⁺/NADPH, as well as unique candidate genes behind each trait. Overall, these findings transform our understanding of the GSH redox system, revealing genetic loci that govern it and proposing new candidate genes to investigate in future mechanistic endeavors.

N-Acetyl Cysteine Targets Hepatic Lipid Accumulation to Curb Oxidative Stress and Inflammation in NAFLD: A Comprehensive Analysis of the Literature

Impaired adipose tissue function and insulin resistance remain instrumental in promoting hepatic lipid accumulation in conditions of metabolic syndrome. In fact, enhanced lipid accumulation together with oxidative stress and an abnormal inflammatory response underpin the development and severity of non-alcoholic fatty liver disease (NAFLD). There are currently no specific protective drugs against NAFLD, and effective interventions involving regular exercise and healthy diets have proved difficult to achieve and maintain. Alternatively, due to its antioxidant and anti-inflammatory properties, there has been growing interest in understanding the therapeutic effects of N-acetyl cysteine (NAC) against metabolic complications, including NAFLD. Here, reviewed evidence suggests that NAC blocks hepatic lipid accumulation in preclinical models of NAFLD. This is in part through the effective regulation of a fatty acid scavenger molecule (CD36) and transcriptional factors such as sterol regulatory element-binding protein (SREBP)-1c/-2 and peroxisome proliferator-activated receptor gamma (PPARγ). Importantly, NAC appears effective in improving liver function by reducing pro-inflammatory markers such as interleukin (IL)-6 IL-1β, tumour necrosis factor alpha (TNF-α) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). This was primarily through the attenuation of lipid peroxidation and enhancements in intracellular response antioxidants, particularly glutathione. Very few clinical studies support the beneficial effects of NAC against NAFLD-related complications, thus well-organized randomized clinical trials are still necessary to confirm its therapeutic potential.

Factors independently associated with cardiorespiratory fitness in patients with non-alcoholic fatty liver disease

Low cardiorespiratory fitness (CRF) is associated with non-alcoholic fatty liver disease (NAFLD) and low CRF is an important risk factor for cardiovascular disease. The factors that influence CRF in NAFLD are poorly understood and it has been suggested that reduced hepatic mitochondrial function (HMF) may be linked to low CRF. Therefore, our aim was to determine the factors associated with CRF in NAFLD.

METHODS

Ninety-seven patients with NAFLD were studied. CRF was assessed by treadmill testing and expressed as maximal O₂ consumption (VO₂ peak) per lean body mass. HMF was assessed by the ¹³ C-ketoisocaproate breath test. Multivariable linear regression modelling was undertaken to test the independence of associations with CRF.

RESULTS

Mean (SD) age was 51 (13) years and 61% were men. With CRF as the outcome, age (B coefficient -0.3, 95%CI -0.4, -0.2, P < .0001), total body fat mass (B coefficient -0.2, 95%CI -0.3, -0.05, P = .01), type 2 diabetes mellitus (T2DM) (B coefficient -3.6, 95%CI -1.1, -6.1, P = .005), smoking status (B coefficient -5.7, 95%CI -1.9, -9.5, P = .004), serum γ-glutamyl transferase (GGT) (B coefficient -0.04, 95%CI -0.05, -0.02, P < .0001), HMF (B coefficient -0.5, 95%CI -0.8, -0.1, P = .01) and diastolic function (B coefficient 0.1, 95%CI 0.05, 0.13, P < .0001) were independently associated with CRF. This model explained 60% of the total variance in CRF (R²  = 0.6, P < .0001); and this model with GGT alone explained 24% of the variance in CRF.

CONCLUSIONS

In patients with NAFLD, HMF is independently associated with CRF and a model with GGT alone explained most of the variance in CRF.

Pemafibrate Dramatically Ameliorated the Values of Liver Function Tests and Fibrosis Marker in Patients with Non-Alcoholic Fatty Liver Disease

Background

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease related to metabolic syndrome, which can progress to liver cirrhosis. Standard medication has not been established. Pemafibrate is a selective peroxisome proliferator-activated receptor (PPAR) α modulator. We retrospectively evaluated the efficacy of pemafibrate in patients with NAFLD.

Methods

We retrospectively enrolled 17 patients (ten men, seven women; median age, 63 years; range, 27-81 years). They were all proven to have fatty liver through imaging and had little or no history of drinking (ethanol consumption of < 20 g/day for women and < 30 g/day for men). They were administered pemafibrate from October 2018 to June 2020.

Results

After administration, serum triglyceride (TG) tended to be decreased (300.5 ± 22.5 to 239.5 ± 34.3 mg/dL, P = 0.06). Serum high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol levels did not change. ALT was significantly decreased (-47.4%) for six months (57.5 ± 8.8 to 30.3 ± 5.8 U/L, P < 0.01). The values of serum GGT significantly decreased (-48.7%) for sixth months (63.9 ± 10.3 to 32.8 ± 6.6 U/L, P < 0.01). Aspartate aminotransferase (AST) to platelet ratio (APRI), a fibrosis marker, also was significantly decreased in the sixth month (0.7 ± 0.1 to 0.4 ± 0.1, P < 0.05). Body mass index (BMI) and hemoglobin A1c (HbA1c) showed no significant change.

Conclusion

Pemafibrate dramatically ameliorated the values of liver function tests and APRI in patients with NAFLD.

Successful treatment of obesity and insulin resistance via ketogenic diet status post Roux-en-Y

This is a single case of a 65-year-old American woman who presented with substantial weight gain and insulin resistance (IR) post-Roux-en-Y gastric bypass (RYGB) surgery. Before RYGB, she had reached 340 lbs (155 kg) and a body mass index (BMI) of 56.6 kg/m2 The surgery resulted in a 70 lbs (32 kg) weight loss, bringing her BMI, per cent total weight loss (%TWL) and per cent excess weight loss (%EWL) to 44.9 kg/m2, 20.6% and 36.8%, respectively. Unfortunately, her BMI would return to 53.6 kg/m2, nearly her pre-RYGB BMI. It was then she sought the guidance of a primary care physician with expertise in nutrition and medical management of obesity, who placed her on a ketogenic diet. One year later, she had lost 102 lbs (46.4 kg), resulting in a BMI, %TWL and %EWL of 36.6 kg/m2, 31.7%, and 63.1%, respectively, also further resulting in significant improvements of her inflammatory biomarkers. This case presentation will explore current literature, covering the effects of obesity on IR, pre-diabetes and other disease-provoking inflammatory biomarkers.