Changes in Glutathione Content in Liver Diseases: An Update

Effect of Pd2Spermine on Mice Brain-Liver Axis Metabolism Assessed by NMR Metabolomics

Cisplatin (cDDP)-based chemotherapy is often limited by severe deleterious effects (nephrotoxicity, hepatotoxicity and neurotoxicity). The polynuclear palladium(II) compound Pd2Spermine (Pd2Spm) has emerged as a potential alternative drug, with favorable pharmacokinetic/pharmacodynamic properties. This paper reports on a Nuclear Magnetic Resonance metabolomics study to (i) characterize the response of mice brain and liver to Pd2Spm, compared to cDDP, and (ii) correlate brain-liver metabolic variations. Multivariate and correlation analysis of the spectra of polar and lipophilic brain and liver extracts from an MDA-MB-231 cell-derived mouse model revealed a stronger impact of Pd2Spm on brain metabolome, compared to cDDP. This was expressed by changes in amino acids, inosine, cholate, pantothenate, fatty acids, phospholipids, among other compounds. Liver was less affected than brain, with cDDP inducing more metabolite changes. Results suggest that neither drug induces neuronal damage or inflammation, and that Pd2Spm seems to lead to enhanced brain anti-inflammatory and antioxidant mechanisms, regulation of brain bioactive metabolite pools and adaptability of cell membrane characteristics. The cDDP appears to induce higher extension of liver damage and an enhanced need for liver regeneration processes. This work demonstrates the usefulness of untargeted metabolomics in evaluating drug impact on multiple organs, while confirming Pd2Spm as a promising replacement of cDDP.

Probiotics ameliorate polyethylene microplastics-induced liver injury by inhibition of oxidative stress in Nile tilapia (Oreochromis niloticus)

Microplastic particles (MPs) are environmental pollutants that can cause varying levels of aquatic toxicity. Probiotics have been shown to reduce the negative effects of toxic substances. However, the protective effect of probiotics against the adverse effects of MPs has yet to be reported. The current study sought to determine the effects of the commercial probiotic AquaStar® Growout on polystyrene (PS)-MPs-mediated hepatic oxidative stress in Nile tilapia (Oreochromis niloticus). Fishes were assigned into four groups: the first group was the control, the second group was exposed to 1 mg/L of 0.5 μm PS-MPs, and the third and fourth groups were exposed to 1 mg/L of 0.5 μm PS-MPs and pre-fed with probiotics at levels of 3 g/kg and 6 g/kg diet, respectively. At the end of the experiment, probiotics administration reversed liver damage caused by the PS-MPs, reducing serum levels of malondialdehyde, aspartate aminotransferase, and alanine aminotransferase, and increasing the total antioxidant capacity. Furthermore, probiotics alleviated PS-MPs-induced oxidative stress by restoring antioxidant enzyme activities (superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase) and reducing oxidized glutathione and enhancing the redox state. Besides, probiotics supplementation decreased the transcriptional level of C-reactive protein and tumor necrosis factor-α following PS-MPs exposure. Furthermore, probiotics counteracted PS-MPs-associated reactive oxygen species production and mitogen-activated protein kinases (MAPKs) phosphorylation status. These findings suggested that probiotics could decrease liver damage caused by PS-MPs through their antioxidant properties and modulation of MAPK signaling pathways.

Discrete Correlation Summation Clustering Reveals Differential Regulation of Liver Metabolism by Thrombospondin-1 in Low-Fat and High-Fat Diet-Fed Mice

Thrombospondin-1 (TSP1) is a matricellular protein with many important roles in mediating carcinogenesis, fibrosis, leukocyte recruitment, and metabolism. We have previously shown a role of diet in the absence of TSP1 in liver metabolism in the context of a colorectal cancer model. However, the metabolic implications of TSP1 regulation by diet in the liver metabolism are currently understudied. Therefore Discrete correlation summation (DCS) was used to re-interrogate data and determine the metabolic alterations of TSP1 deficiency in the liver, providing new insights into the role of TSP1 in liver injury and the progression of liver pathologies such as nonalcoholic fatty liver disease (NAFLD). DCS analysis provides a straightforward approach to rank covariance and data clustering when analyzing complex data sets. Using this approach, our previous liver metabolite data was re-analyzed by comparing wild-type (WT) and Thrombospondin-1 null (Thbs1-/-) mice, identifying changes driven by genotype and diet. Principal component analysis showed clustering of animals by genotype regardless of diet, indicating that TSP1 deficiency alters metabolite handling in the liver. High-fat diet consumption significantly altered over 150 metabolites in the Thbs1-/- livers versus approximately 90 in the wild-type livers, most involved in amino acid metabolism. The absence of Thbs1 differentially regulated tryptophan and tricarboxylic acid cycle metabolites implicated in the progression of NAFLD. Overall, the lack of Thbs1 caused a significant shift in liver metabolism with potential implications for liver injury and the progression of NAFLD.

Synthesis, Characterization, and Antimicrobial and Antiproliferative Effects of CuO-TiO2-Chitosan-Escin Nanocomposites on Human Leukemic MOLT4 Cells

Nanocomposites comprised of CuO-TiO2-chitosan-escin, which has adjustable physicochemical properties, provide a solution for therapeutic selectivity in cancer treatment. By controlling the intrinsic signaling primarily through the mitochondrial signaling pathway, we desired nanocomposites with enhanced anticancer activity by containing CuO-TiO2-chitosan-escin. The metal oxides CuO and TiO2, the natural polymer chitosan, and a phytochemical compound escin were combined to form CuO-TiO2-chitosan-escin nanocomposites. The synthesized nanocomposites were confirmed and characterized using FTIR spectroscopy, TEM, and UV-Vis absorption spectroscopy. A human leukemia cell line (MOLT-4) was used to assess the efficacy and selectivity of nanocomposites. Based on a cytotoxicity study, CuO-TiO2-chitosan-escin nanocomposites had inhibition concentrations (IC50) of 13.68, 8.9, and 7.14 µg/mL against human T lymphoblast cells after 24, 48, and 72 h of incubation, respectively. Compared with untreated MOLT-4 cells, CuO-TiO2-chitosan-escin nanocomposite-treated cells significantly increased (p < 0.05) caspase-3, -8, and -9 and decreased the levels of antioxidant enzymes GR, SOD, and GSH. Furthermore, MDA for lipid peroxidase and ROS levels significantly increased (p < 0.05) in the treated cells than in the untreated cells. Remarkably, CuO-TiO2-chitosan-escin nanocomposite-mediated control of cell cycles were mainly achieved through the activation of caspase-3, -8, and -9.

Colorimetric determination of biothiols based on peroxidase-mimicking Ag nanoparticles decorated Ti3C2 nanosheets

Ag nanoparticle-decorated Ti₃C₂ nanosheets (AgNPs@Ti₃C₂ NSs) were facilely synthesized via a self-reduction approach, in which Ti₃C₂ NSs acted as both reductant and supporter. The AgNPs@Ti₃C₂ NS nanocomposite exhibited excellent peroxidase-like activity with o-phenylenediamine (OPD) and H₂O₂ as substrates. The catalytic behavior followed the typical Michaelis-Menten kinetics; Michaelis constant (K_m) and maximum initial velocity (V_max) for OPD were 0.263 mM and 43.2 × 10^-8 M^-1 s, indicating high affinity and high catalytic efficiency towards OPD. The catalytic mechanism was revealed to be an accelerated electron transfer process. Based on the inhibition effect on the peroxidase-like activity of AgNPs@Ti₃C₂ NSs, a simple, fast, and sensitive colorimetric method for detection of low-weight biothiols (cysteine (Cys), homocysteine (Hcy), and glutathione (GSH)) was developed by measuring the absorbance at 425 nm. The colorimetric method displayed wide linear range (50 nM to 50 μM for Cys, 10 nM to 250 μM for Hcy, 10 nM to 50 μM for GSH), low limit of detection (48.5 nM for Cys, 5.5 nM for Hcy, 7.0 nM for GSH), and good selectivity and short assay time (3 min). Moreover, the feasibility of this colorimetric sensor was demonstrated by accurately determining Cys in diluted human serum samples; good recovery (95.9-101.0%) and low relative standard deviations (2.8-4.9%) were obtained, showing great promise for point-of-care test in clinical samples.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Signal On-Off Electrochemical Sensor for Glutathione Based on a AuCu-Decorated Zr-Containing Metal-Organic Framework via Solid-State Electrochemistry of Cuprous Chloride

A novel signal on-off glutathione (GSH) electrochemical sensor was developed based on a AuCu bimetal-decorated Zr-containing metal-organic framework (Zr-MOF), in which a signal amplification strategy promoted by solid-state electrochemistry of cuprous chloride (CuCl) was used. The Zr-MOF with a large surface area can be effectively used as the substrate for the in situ growth of AuCu bimetals to obtain the Zr-MOF@AuCu nanocomposite. The interaction between Cu in Zr-MOF@AuCu and Cl^- in the solution accompanied with the formation of CuCl displays an enlarged stable oxidation current, which greatly declines with the addition of GSH owing to the specific Cu-GSH interaction. The conversion of CuCl into Cu-GSH triggered the "crowding-out effect" and resulted in a sharp drop in the peak current of CuCl, which can realize the ultrasensitive and selective detection of GSH. The detection mechanism was investigated, and the detection range was 10 pM-1 mM with the detection limit as low as 2.67 pM. The special response mechanism for the detection of GSH allows the highly selective detection of GSH in various real samples with reliable results, endowing the proposed electroanalysis sensor with broad application prospects in biological and food analysis.

The potential role of febrile condition in reversing the hepatoprotective effects of quercetin in the livers of LPS-presensitized mice

AIMS

Consumption of nutraceuticals without enough data regarding their interactions has raised safety concerns. Importantly, consumption of some natural-products in health-compromised conditions has caused liver injury due to the evolved pro-oxidant load. This study evaluates the safety of quercetin (QUR), as an extensively-used flavonoid owing to its antioxidant and hepatoprotective activities, in normal- and lipopolysaccharides (LPS)-primed livers, and to investigate the influence of the LPS-induced mild inflammatory/febrile condition on QUR effects.

MAIN METHODS

For liver priming, a non-injurious LPS dose that mediates limited inflammation/mild fever was chosen. Selection of QUR dose/duration of treatment, for a coherent combination-regimen, was also adopted. Single LPS i.p injection (1.5 mg/kg)/oral QUR (20 mg/kg/day, IG) for 5-days was the optimal regimen for the combination group. On day-6, serum ALT/AST/ALP levels were measured, as liver-damage biomarkers. Hepatic; MDA/GSH were determined, as oxidative-stress measures, Bcl-2/cleaved-caspase-3 were assessed as apoptosis biomarkers, IL-6 expression/NF-κB/Nrf-2 immunoreactivities were evaluated as regulators for inflammation.

KEY FINDINGS

Exaggerated hepatic injury was seen upon QUR treatment in LPS-presensitized mice; as evidenced by liver histopathological degeneration, which was confirmed by biochemical elevations of serum AST/ALT/ALP, along with oxidant-burden increase (↑MDA/↓GSH) and molecular augmentation of inflammation (NF-κB/IL-6 activation) that led to enhancement of proapoptotic signaling (caspase-3 activation/Bcl-2 inhibition). Such events were accompanied by potentiation of endogenous anti-inflammatory/antioxidant response (↑ hepatic Nrf-2).

SIGNIFICANCE

The study highlights caution when QUR is consumed in health-compromised conditions, by revealing the role of fever/mild inflammation in enhancing liver toxicity upon QUR utilization, which was not apparent with moderate consumption of QUR-alone.

Specific Strains of Faecalibacterium prausnitzii Ameliorate Nonalcoholic Fatty Liver Disease in Mice in Association with Gut Microbiota Regulation

Evidence linking Faecalibacterium prausnitzii abundance to nonalcoholic fatty liver disease (NAFLD) is accumulating; however, the causal relationship remains obscure. In this study, 12 F. prausnitzii strains were orally administered to high fat diet fed C57BL/6J mice for 12 weeks to evaluate the protective effects of F. prausnitzii on NAFLD. We found that five F. prausnitzii strains, A2-165, LB8, ZF21, PL45, and LC49, significantly restored serum lipid profiles and ameliorated glucose intolerance, adipose tissue dysfunction, hepatic steatosis, inflammation, and oxidative stress in a mouse model of NAFLD. Moreover, two strains, LC49 and LB8, significantly enhanced short-chain fatty acid (SCFA) production and modulated the gut microbiota. Based on the combined analysis of linear discriminant analysis effect size and microbial communities, the core microbiome related to NAFLD comprised Odoribacter, Roseburia, Erysipelatoclostridium, Tyzzerella, Faecalibaculum, Blautia, and Acetatifactor, and the last five genera can be reversed by treatment with the LC49 and LB8 strains. Additionally, the LC49 and LB8 strains enriched Lactobacillus, Ileibacterium, Faecalibacterium, Dubosiella, and Bifidobacterium and downregulated pathways involving carbohydrate metabolism, amino acid metabolism, and fatty acid biosynthesis. Interestingly, LC49 supplementation also upregulated tryptophan metabolism, glutathione metabolism, and valine, leucine, and isoleucine degradation, which might be related to NAFLD prevention. Collectively, F. prausnitzii LC49 and LB8 exerted considerable anti-NAFLD and microbiota-regulating effects, indicating their potential as probiotic agents for NAFLD treatment.

Oxidative Stress in Chronic Hepatitis B—An Update

In recent years, the role of oxidative stress has been investigated in an increasing number of infections. There is a close link between the inflammation that accompanies infections and oxidative stress. Excessive reactive oxygen species induce harmful effects on cell components, including lipids, proteins, and nucleic acids. A growing body of evidence attests to the role of oxidative stress in the pathogenesis of viral liver infections, especially in hepatitis C virus (HCV) infection. Regarding hepatitis B virus (HBV) infection, the data are limited, but important progress has been achieved in recent years. This review presents the latest advances pertaining to the role of the oxidative stress byproducts in the pathogenesis of chronic hepatitis B, constituting a source of potential new markers for the evaluation and monitoring of patients with chronic hepatitis B.

NADPH Oxidases Connecting Fatty Liver Disease, Insulin Resistance and Type 2 Diabetes: Current Knowledge and Therapeutic Outlook

Nonalcoholic fatty liver disease (NAFLD), characterized by ectopic fat accumulation in hepatocytes, is closely linked to insulin resistance and is the most frequent complication of type 2 diabetes mellitus (T2DM). One of the features connecting NAFLD, insulin resistance and T2DM is cellular oxidative stress. Oxidative stress refers to a redox imbalance due to an inequity between the capacity of production and the elimination of reactive oxygen species (ROS). One of the major cellular ROS sources is NADPH oxidase enzymes (NOX-es). In physiological conditions, NOX-es produce ROS purposefully in a timely and spatially regulated manner and are crucial regulators of various cellular events linked to metabolism, receptor signal transmission, proliferation and apoptosis. In contrast, dysregulated NOX-derived ROS production is related to the onset of diverse pathologies. This review provides a synopsis of current knowledge concerning NOX enzymes as connective elements between NAFLD, insulin resistance and T2DM and weighs their potential relevance as pharmacological targets to alleviate fatty liver disease.

Amelioration of oxidative damage parameters by carvacrol on methanol-induced liver injury in rats

The methanol metabolite that causes hepatotoxicity is formic acid, generating reactive oxygen radical formation and cell damage. Carvacrol is an antioxidant monoterpenic phenol produced from Thymus vulgaris. This study aimed to investigate the effects of carvacrol on methanol-induced oxidative liver damage in rats. Eighteen rats were divided into three groups. Methotrexate was administered orally for 7 days to methotrexate+methanol (MTM) and methotrexate+methanol+carvacrol (MMC) groups. Methotrexate was given before methanol to cause methanol poisoning. Distilled water was given to the healthy group (HG) as a solvent. At the end of the 7th day, 20% methanol was administered orally at a dose of 3 g/kg to the MTM and MMC groups. Four hours after methanol administration, 50 mg/kg carvacrol was injected intraperitoneally into the MMC group. Animals were sacrificed 8 h after carvacrol injection. Biochemical markers were studied in the excised liver tissue and blood serum samples, and histopathological evaluations were made. Severe hemorrhage, hydropic degeneration, pycnosis, and mononuclear cell infiltration were observed in the liver of the MTM group. Additionally, the levels of malondialdehyde (MDA), total oxidant status (TOS), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were significantly higher, and total glutathione (tGSH) and total antioxidant status (TAS) were significantly lower in the MTM group compared to HG (P<0.001). Carvacrol prevented the increase in MDA, TOS, ALT and AST levels with methanol and the decrease in tGSH and TAS levels (P<0.001), and alleviated the histopathological damage. Carvacrol may be useful in the treatment of methanol-induced liver damage.

Monitoring of glutathione using ratiometric fluorescent sensor based on MnO2 nanosheets simultaneously tuning the fluorescence of Rhodamine 6G and thiamine hydrochloride

L-glutathione (GSH) which has reducibility and integrated detoxification plays an important role in maintaining normal immune system function. Its abnormal levels are relevant to some clinical diseases. In this work, a facile ratiometric fluorescence sensor for GSH was designed based on MnO₂ nanosheets, Thiamine hydrochloride (VB₁) and Rhodamine 6G (R6G). VB₁ could be oxidized into fluorescent ox-VB₁ due to the strong oxidizing property of MnO₂, and MnO₂ nanosheets simultaneously could quench the fluorescence of R6G based on the inner filter effect (IFE). MnO₂ could react with GSH to form Mn²⁺, which caused its losing oxidizing property and quenching capacity. According to this principle, the concentration of ox-VB₁ diminished, resulting in its fluorescence intensity decreasing at 455 nm and the fluorescence of R6G recovering at 560 nm. Under optimal conditions, the VB₁-MnO₂-R6G detection system showed a wide linear range towards GSH in the range of 1.0-300.0 µmolL^-1 with a low detection limit reaching 0.52 µmolL^-1. Furthermore, the method was also applied in the determination of GSH in human serum.

Deficiency in glutathione synthesis and reduction contributes to the pathogenesis of colitis-related liver injury

OBJECTIVES

Liver disease is the most common extra-intestinal manifestation of ulcerative colitis (UC), but the underlying pathogenesis is still not clarified. It is well accepted that the occurrence of UC-related liver disease has close correlation with immune activation, intestinal bacterial liver translocation, inflammatory cytokine storm, and the disturbance of bile acid circulation. The occurrence of UC-related liver disease makes the therapy difficult, therefor study on the pathogenesis of UC-related liver injury is of great significance for its prevention and treatment. Glutathione (GSH) shows multiple physiological activities, such as free radical scavenging, detoxification metabolism and immune defense. The synthesis and the oxidation-reduction all contribute to GSH antioxidant function. It is reported that the deficiency in hepatic GSH antioxidant function participates in multiple liver diseases, but whether it participates in the pathogenesis of UC-related liver injury is still not clear. This study aims to investigate the feature and underlying mechanism of GSH synthesis and oxidation-reduction function during the development of UC, which will provide useful information for the pathogenesis study on UC-related liver injury.

METHODS

UC model was induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS)-ethanol solution (5 mg/0.8 mL per rat, 50% ethanol) via intra-colonic administration in rats, and the samples of serum, liver, and colon tissue of rats were collected at the 3rd, 5th, and 7th days post TNBS. The severity degree of colitis was evaluated by measuring the disease activity index, colonic myeloperoxidase activity, and histopathological score, and the degree of liver injury was evaluated by histopathological score and the serum content of alanine aminotransferase. Spearman correlation analysis was also conducted between the degree of colonic lesions and index of hepatic histopathological score as well as serum aspartate aminotransferase level to clarify the correlation between liver injury and colitis. To evaluate the hepatic antioxidant function of GSH in UC rats, hepatic GSH content, enzyme activity of GSH peroxidase (GSH-Px), and GSH reductase (GR) were determined in rats at the 3rd, 5th, and 7th days post TNBS, and the protein expressions of glutamine cysteine ligase (GCL), GSH synthase, GSH-Px, and GR in the liver of UC rats were also examined by Western blotting.

RESULTS

Compared with the control, the disease activity index, colonic myeloperoxidase activity, and histopathological score were all significantly increased at the 3rd, 5th, and 7th days post TNBS (all P<0.01), the serum aspartate aminotransferase level and hepatic histopathologic score were also obviously elevated at the 7th day post TNBS (all P<0.05). There was a significant positive correlation between the degree of liver injury and the severity of colonic lesions (P=0.000 1). Moreover, compared with the control, hepatic GSH content and the activity of GSH-Px and GR were all significantly decreased at the 3rd and 5th days post TNBS (P<0.05 or P<0.01), and the protein expressions of GCL, GSH-Px, and GR were all obviously down-regulated at the 3rd, 5th, and 7th days post TNBS (P<0.05 or P<0.01).

CONCLUSIONS

There is a significant positive correlation between the degree of liver injury and the severity of colonic lesions, and the occurrence of reduced hepatic GSH synthesis and decreased GSH reduction function is obviously earlier than that of the liver injury in UC rats. The reduced hepatic expression of enzymes that responsible for GSH synthesis and reduction may contribute to the deficiency of GSH synthesis and oxidation-reduction function, indicating that the deficiency in GSH antioxidant function may participate in the pathogenesis of UC related liver injury.

Effectiveness and Economic Evaluation of Polyene Phosphatidyl Choline in Patients With Liver Diseases Based on Real-World Research

Aims: Liver disease has high prevalence, number, and disease burden in China, and polyene phosphatidyl choline (PPC) is a widely used liver protective drug. We aim to explore the effectiveness and economy of PPC in patients with liver diseases based on real-world research and compare with other hepatoprotective drugs.

Methods: This is a “three-phase” study from three medical centers, including descriptive study of patients using PPC injection, self-control case study of patients using PPC injection, and specific-disease cohort study of patients using PPC injection or control drugs. The major measurements of liver function for effectiveness analysis were the alanine transaminase (ALT) level changes and recovery rate. The main statistical methods were Wilcoxon signed rank test, χ² test, and Mann–Whitney U test. Propensity score matching was applied to reduce bias. Cost-effectiveness analysis, cost minimization analysis, and sensitivity analysis were used for economic evaluation.

Results: PPC alone or in combination with glutathione and magnesium isoglycyrrhizinate shows less total hospitalization cost (p < 0.05) and smaller cost-effectiveness ratio and was effective in protecting liver function, especially in patients with liver transplantation or postoperation of nontumor liver disease (ALT decreased significantly after PPC treatment; p < 0.05). Glutathione and magnesium isoglycyrrhizinate combined with PPC could enhance the protective function of liver.

Conclusion: PPC was an effective and economic liver protective drug in patients with specific liver diseases, and PPC could enhance the liver protective function of glutathione and magnesium isoglycyrrhizinate.

The Symbiotic Effect of a New Nutraceutical with Yeast β-Glucan, Prebiotics, Minerals, and Silybum marianum (Silymarin) for Recovering Metabolic Homeostasis via Pgc-1α, Il-6, and Il-10 Gene Expression in a Type-2 Diabetes Obesity Model

The use of natural products and derivatives for the prevention and control of non-communicable chronic diseases, such as type-2 diabetes (T2D), obesity, and hepatic steatosis is a way to achieve homeostasis through different metabolic pathways. Thus, male C57BL/6 mice were divided into the following groups: high-fat diet (HFD) vehicle, HFD + Supplemented, HFD + Supplemented_S, and isolated compounds. The vehicle and experimental formulations were administered orally by gavage once a day over the four weeks of the diet (28 consecutive days). We evaluated the energy homeostasis, cytokines, and mitochondrial gene expression in these groups of mice. After four weeks of supplementation, only the new nutraceutical group (HFD + Supplemented) experienced reduced fasting glycemia, insulin, HOMA index, HOMA-β, dyslipidemia, ectopic fat deposition, and hepatic fibrosis levels. Additionally, the PPARγ coactivator 1 α (Pgc-1α), interleukin-6 (Il-6), and interleukin-10 (Il-10) gene expression were augmented, while hepatic steatosis decreased and liver parenchyma was recovered. The glutathione-S-transferase activity status was found to be modulated by the supplement. We discovered that the new nutraceutical was able to improve insulin resistance and hepatic steatosis mainly by regulating IL-6, IL-10, and Pgc-1α gene expression.

Detailed Molecular Mechanisms Involved in Drug-Induced Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis: An Update

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are some of the biggest public health challenges due to their spread and increasing incidence around the world. NAFLD is characterized by intrahepatic lipid deposition, accompanied by dyslipidemia, hypertension, and insulin resistance, leading to more serious complications. Among the various causes, drug administration for the treatment of numerous kinds of diseases, such as antiarrhythmic and antihypertensive drugs, promotes the onset and progression of steatosis, causing drug-induced hepatic steatosis (DIHS). Here, we reviewed in detail the major classes of drugs that cause DIHS and the specific molecular mechanisms involved in these processes. Eight classes of drugs, among the most used for the treatment of common pathologies, were considered. The most diffused mechanism whereby drugs can induce NAFLD/NASH is interfering with mitochondrial activity, inhibiting fatty acid oxidation, but other pathways involved in lipid homeostasis are also affected. PubMed research was performed to obtain significant papers published up to November 2021. The key words included the class of drugs, or the specific compound, combined with steatosis, nonalcoholic steatohepatitis, fibrosis, fatty liver and hepatic lipid deposition. Additional information was found in the citations listed in other papers, when they were not displayed in the original search.

Maresin-1 Prevents Liver Fibrosis by Targeting Nrf2 and NF-κB, Reducing Oxidative Stress and Inflammation

Liver fibrosis is a complex process characterized by the excessive accumulation of extracellular matrix (ECM) and an alteration in liver architecture, as a result of most types of chronic liver diseases such as cirrhosis, hepatocellular carcinoma (HCC) and liver failure. Maresin-1 (MaR1) is derivative of ω-3 docosahexaenoic acid (DHA), which has been shown to have pro-resolutive and anti-inflammatory effects. We tested the hypothesis that the application of MaR1 could prevent the development of fibrosis in an animal model of chronic hepatic damage. Sprague-Dawley rats were induced with liver fibrosis by injections of diethylnitrosamine (DEN) and treated with or without MaR1 for four weeks. In the MaR1-treated animals, levels of AST and ALT were normalized in comparison with DEN alone, the hepatic architecture was improved, and inflammation and necrotic areas were reduced. Cell proliferation, assessed by the mitotic activity index and the expression of Ki-67, was increased in the MaR1-treated group. MaR1 attenuated liver fibrosis and oxidative stress was induced by DEN. Plasma levels of the pro-inflammatory mediators TNF-α and IL-1β were reduced in MaR1-treated animals, whereas the levels of IL-10, an anti-inflammatory cytokine, increased. Interestingly, MaR1 inhibited the translocation of the p65 subunit of NF-κB, while increasing the activation of Nrf2, a key regulator of the antioxidant response. Finally, MaR1 treatment reduced the levels of the pro-fibrotic mediator TGF-β and its receptor, while normalizing the hepatic levels of IGF-1, a proliferative agent. Taken together, these results suggest that MaR1 improves the parameters of DEN-induced liver fibrosis, activating hepatocyte proliferation and decreasing oxidative stress and inflammation. These results open the possibility of MaR1 as a potential therapeutic agent in fibrosis and other liver pathologies.

Intermittent hypoxia aggravates non-alcoholic fatty liver disease via RIPK3-dependent necroptosis-modulated Nrf2/NFκB signaling pathway

AIMS

Hepatocyte necroptosis is a critical event in the progression of non-alcoholic fatty liver disease (NAFLD). Obstructive sleep apnea hypopnea syndrome (OSAHS) and chronic intermittent hypoxia (CIH) may be linked with the pathogenesis and the severity of NAFLD. However, the potential role of necroptosis in OSAHS-associated NAFLD has not been evaluated. The present study investigated whether IH could affect NAFLD progression through promoting receptor-interacting protein kinase-3 (RIPK3)-dependent necroptosis, oxidative stress, and inflammatory response, and further elucidated the underlying molecular mechanisms.

MAIN METHODS

LO2 cells were treated with palmitic acid (PA) and subjected to IH, and necroptosis, oxidative stress, and inflammation were assessed. The high-fat choline-deficient (HFCD)-fed mouse model was also used to assess the effects of CIH in experimental NAFLD in vivo.

KEY FINDINGS

In this study, we found that RIPK3-mediated necroptosis was activated both in the PA plus IH-treated LO2 cells and liver of HFCD/CIH mice, and which could trigger oxidative stress and inflammatory response by decreasing Nrf2 and increasing p-P65. RIPK3 downregulation significantly reduced hepatocyte necroptosis, and ameliorated oxidative stress and inflammation through modulating Nrf2/NFκB pathway in vitro and vivo. Similarly, pretreatment with TBHQ, an activator of Nrf2, effectively blocked the generation of oxidative productions and inflammatory cytokines. In addition, RIPK3 inhibitor GSK-872 or TBHQ administration obviously alleviated hepatic injury, including histology, transaminase activities, and triglyceride contents in vivo.

SIGNIFICANCE

IH aggravates NAFLD via RIPK3-dependent necroptosis-modulated Nrf2/NFκB signaling pathway, and which should be considered as a potential therapeutic strategy for the treatment of NAFLD with OSASH.

The Prognostic Role of Glutathione and Its Related Antioxidant Enzymes in the Recurrence of Hepatocellular Carcinoma

The imbalance of high oxidative stress and low antioxidant capacities is thought to be a significant cause of the development and progression of hepatocellular carcinoma (HCC). However, the impact of oxidative stress, glutathione (GSH), and its related antioxidant enzymes on the recurrence of HCC has not been investigated. The purpose of this study was to compare the changes to oxidative stress and GSH-related antioxidant capacities before and after tumor resection in patients with HCC recurrence and non-recurrence. We also evaluated the prognostic significance of GSH and its related enzymes in HCC recurrence. This was a cross-sectional and follow-up study. Ninety-two HCC patients who were going to receive tumor resection were recruited. We followed patients' recurrence and survival status until the end of the study, and then assigned patients into the recurrent or the non-recurrent group. The tumor recurrence rate was 52.2% during the median follow-up period of 3.0 years. Patients had significantly lower plasma malondialdehyde level, but significantly or slightly higher levels of GSH, glutathione disulfide, trolox equivalent antioxidant capacity, glutathione peroxidase (GPx), and glutathione reductase (GR) activities after tumor resection compared to the respective levels before tumor resection in both recurrent and non-recurrent groups. GSH level in HCC tissue was significantly higher than that in adjacent normal tissue in both recurrent and non-recurrent patients. Decreased plasma GPx (HR = 0.995, p = 0.01) and GR (HR = 0.98, p = 0.04) activities before tumor resection, and the increased change of GPx (post-pre-resection) (HR = 1.004, p = 0.03) activity were significantly associated with the recurrence of HCC. These findings suggest there might be a possible application of GPx or GR as therapeutic targets for reducing HCC recurrence.

Curc-mPEG454, a PEGylated curcumin derivative, as a multi-target anti-fibrotic prodrug

Our previous studies demonstrated that Curc-mPEG454, a curcumin derivative modified with short-chain polyethylene glycol (PEG), not only increased the blood concentration of curcumin, but also retained its anti-inflammatory activity. Here, we aimed to evaluate the anti-fibrotic effect of Curc-mPEG454 on a rat liver fibrosis model induced by carbon tetrachloride (CCl₄), and to explore the underlying mechanisms by integrating our total liver RNA sequencing (RNA-seq) data with recent liver single-cell sequencing (scRNA-seq) studies. 50 mg/kg and 100 mg/kg Curc-mPEG454 treatment significantly reduced the elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) induced by CCl₄, and the incidence of liver cirrhosis decreased from 75% to 37% and 35%, respectively. RNA-seq analysis revealed that Curc-mPEG454 significantly upregulated aldehyde oxidase 1 (AOX1) while downregulated cytochrome p450 26A1 (CYP26A1) and cytochrome p450 26B1 (CYP26B1) resulting in restoring liver retinoic acid (RA) level, increased glutamate-cysteine ligase catalytic subunit (GCLC) and glutamate-cysteine ligase modifier subunit (GCLM) expression to synthesize hepatic glutathione (GSH), and inhibited liver inflammation via down-regulating the Prostaglandin E Synthase 2 (PTGES2)/prostacyclin E2 (PGE2) signaling. Integrating scRNA-seq data revealed that Curc-mPEG454 effectively inhibited the expansion of scar-associated macrophage subpopulation and scar-producing myofibroblasts in the damaged liver, and remodeled the fibrotic niche via regulation of ligand-receptor interactions including platelet-derived growth factor-B (PDGF-B)/platelet-derived growth factor receptor-α (PDGFR-α) signaling. As a multi-target prodrug, PEGylated curcumin deserves further attention and research.

The acute systemic toxicity of thallium in rats produces oxidative stress: attenuation by metallothionein and Prussian blue

Thallium (TI) is one of the most toxic heavy metals. Human exposure to Tl occurs through contaminated drinking water and from there to food, a threat to health. Recently, environmental contamination by Tl has been reported in several countries, urging the need for studies to determine the impact of endogenous and exogenous mechanisms preventing thallium toxicity. The cytoprotective effect of metallothionein (MT), a protein with high capacity to chelate metals, at two doses (100 and 600 µg/rat), was tested. Prussian blue (PB) (50 mg/kg) was administered alone or in combination with MT. A dose of Tl (16mg/kg) was injected i.p. to Wistar rats. Antidotes were administered twice daily, starting 24h after Tl injection, for 4 days. Tl concentrations diminished in most organs (p < 0.05) by effect of PB, alone or in combination with MT, whereas MT alone decreased Tl concentrations in testis, spleen, lung and liver. Likewise, brain thallium also diminished (p < 0.05) by effect of PB and MT alone or in combination in most of the regions analyzed (p < 0.05). The greatest diminution of Tl was achieved when the antidotes were combined. Plasma markers of renal damage increased after Tl administration, while PB and MT, either alone or in combination, prevented the raise of those markers. Only MT increased the levels of reduced glutathione (GSH) in the kidney. Finally, increased Nrf2 was observed in liver and kidney, after treatment with MT alone or in combination with PB. Results showed that MT alone or in combination with PB is cytoprotective after thallium exposure.

The Link between Type 2 Diabetes Mellitus and the Polymorphisms of Glutathione-Metabolizing Genes Suggests a New Hypothesis Explaining Disease Initiation and Progression

The present study investigated whether type 2 diabetes (T2D) is associated with polymorphisms of genes encoding glutathione-metabolizing enzymes such as glutathione synthetase (GSS) and gamma-glutamyl transferase 7 (GGT7). A total of 3198 unrelated Russian subjects including 1572 T2D patients and 1626 healthy subjects were enrolled. Single nucleotide polymorphisms (SNPs) of the GSS and GGT7 genes were genotyped using the MassArray-4 system. We found that the GSS and GGT7 gene polymorphisms alone and in combinations are associated with T2D risk regardless of sex, age, and body mass index, as well as correlated with plasma glutathione, hydrogen peroxide, and fasting blood glucose levels. Polymorphisms of GSS (rs13041792) and GGT7 (rs6119534 and rs11546155) genes were associated with the tissue-specific expression of genes involved in unfolded protein response and the regulation of proteostasis. Transcriptome-wide association analysis has shown that the pancreatic expression of some of these genes such as EDEM2, MYH7B, MAP1LC3A, and CPNE1 is linked to the genetic risk of T2D. A comprehensive analysis of the data allowed proposing a new hypothesis for the etiology of type 2 diabetes that endogenous glutathione deficiency might be a key condition responsible for the impaired folding of proinsulin which triggered an unfolded protein response, ultimately leading to beta-cell apoptosis and disease development.

Emergence of SGLT2 Inhibitors as Powerful Antioxidants in Human Diseases

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of oral glucose-lowering agents. Apart from their glucose-lowering effects, large clinical trials assessing certain SGLT2 inhibitors have revealed cardiac and renal protective effects in non-diabetic patients. These excellent outcomes motivated scientists and clinical professionals to revisit their underlying mechanisms. In addition to the heart and kidney, redox homeostasis is crucial in several human diseases, including liver diseases, neural disorders, and cancers, with accumulating preclinical studies demonstrating the therapeutic benefits of SGLT2 inhibitors. In the present review, we aimed to update recent advances in the antioxidant roles of SGLT2 inhibitors in common but debilitating human diseases. We anticipate that this review will guide new research directions and novel therapeutic strategies for diabetes, cardiovascular diseases, nephropathies, liver diseases, neural disorders, and cancers in the era of SGLT2 inhibitors.

Non-Alcoholic Fatty Liver Disease in Children

Background and Objectives: The prevalence of pediatric non-alcoholic fatty liver disease is increasing. A lot of new data are published regularly. Materials and Methods: Original clinical studies, review articles, and guidelines in children were searched for and the most relevant included in this review. Results: A total of 138 retrieved papers were classified into pathogenesis, epidemiology, diagnosis, and treatment. Pathogenesis is currently explained with the “multi hit hypothesis”, with complex interactions of genetic and environmental factors which trigger inflammation in steatotic liver. The prevalence is rising. A diagnosis can be made with laboratory tests, imaging, and liver biopsy after the exclusion of other causes of liver steatosis. The mainstay of treatment is lifestyle modification consisting of dietary intervention and increased physical activity. The progression to liver cirrhosis can occur even in children. Conclusions: Non-alcoholic fatty liver disease in children is a part of a metabolic syndrome in the majority of patients. Due to its complex etiology and high prevalence, multidisciplinary teams, together with public health professionals, should be involved in its treatment.

Effects of C60 Fullerene on Thioacetamide-Induced Rat Liver Toxicity and Gut Microbiome Changes

Thioacetamide (TAA) is widely used to study liver toxicity accompanied by oxidative stress, inflammation, cell necrosis, fibrosis, cholestasis, and hepatocellular carcinoma. As an efficient free radical's scavenger, C60 fullerene is considered a potential liver-protective agent in chemically-induced liver injury. In the present work, we examined the hepatoprotective effects of two C60 doses dissolved in virgin olive oil against TAA-induced hepatotoxicity in rats. We showed that TAA-induced increase in liver oxidative stress, judged by the changes in the activities of SOD, CAT, GPx, GR, GST, the content of GSH and 4-HNE, and expression of HO-1, MnSOD, and CuZnSOD, was more effectively ameliorated with a lower C60 dose. Improvement in liver antioxidative status caused by C60 was accompanied by a decrease in liver HMGB1 expression and an increase in nuclear Nrf2/NF-κB p65 ratio, suggesting a reduction in inflammation, necrosis and fibrosis. These results were in accordance with liver histology analysis, liver comet assay, and changes in serum levels of ALT, AST, and AP. The changes observed in gut microbiome support detrimental effects of TAA and hepatoprotective effects of low C60 dose. Less protective effects of a higher C60 dose could be a consequence of its enhanced aggregation and related pro-oxidant role.