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Background: Macrophage migration inhibitory factor (MIF) is a multipotent cytokine that contributes to the inflammatory response to chemical liver injury. This cytokine exhibits pro- and anti-inflammatory effects depending on the etiology and stage of liver disease. Objective: Our study aimed to investigate the role of MIF in oxidative stress and inflammation in the liver, and modulatory effects of betaine on MIF in thioacetamide (TAA)-induced chronic hepatic damage in mice. Methods: The experiment was performed on wild type and knockout MIF-/- C57BL/6 mice. They were divided into the following groups: control; Bet-group that received betaine (2% wt/v dissolved in drinking water); MIF-/- mice group; MIF-/-+Bet; TAA-group that received TAA (200 mg/kg b.w.), intraperitoneally, 3x/week/8 weeks); TAA+Bet; MIF-/-+TAA, and MIF-/-+TAA+Bet. In TAA- and Bet-treated groups, animals received the same doses. After eight weeks of treatment, blood samples were collected for biochemical analysis, and liver specimens were prepared for the assessment of parameters of oxidative stress and inflammation. Results: In MIF-/-mice, TAA reduced transaminases, γ-glutamyltranspeptidase, bilirubin, malondialdehyde (MDA), oxidative protein products (AOPP), total oxidant status (TOS), C-reactive protein (CRP), IL-6, IFN-γ, and increased thiols and total antioxidant status (TAS). Betaine attenuated the mechanism of MIF and mediated effects in TAA-induced liver injury, reducing transaminases, γ-glutamyltranspeptidase, bilirubin, MDA, AOPP, TOS, CRP, IL-6, IFN-g, and increasing thiols. Conclusion: MIF is a mediator in hepatotoxic, pro-oxidative, and proinflammatoryeffects of TAA-induced liver injury. MIF-targeted therapy can potentially mitigate oxidative stress and inflammation in the liver, but the exact mechanism of its action requires further investigation. Betaine increases anti-oxidative defense and attenuates hepatotoxic effects of MIF, suggesting that betaine can be used for the prevention and treatment of liver damage.

Dysfunction of the endocannabinoid system (ES) has been identified in nonalcoholic fatty liver disease (NAFLD) and associated metabolic disorders. Cannabinoid receptor type 1 (CB1) expression is largely dependent on nutritional status. Thus, individuals suffering from NAFLD and metabolic syndrome (MS) have a significant increase in ES activity. Furthermore, oxidative/ nitrosative stress and inflammatory process modulation in the liver are highly influenced by the ES. Numerous experimental studies indicate that oxidative and nitrosative stress in the liver is associated with steatosis and portal inflammation during NAFLD. On the other hand, inflammation itself may also contribute to reactive oxygen species (ROS) production due to Kupffer cell activation and increased nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. The pathways by which endocannabinoids and their lipid-related mediators modulate oxidative stress and lipid peroxidation represent a significant area of research that could yield novel pharmaceutical strategies for the treatment of NAFLD. Cumulative evidence suggested that the ES, particularly CB1 receptors, may also play a role in inflammation and disease progression toward steatohepatitis. Pharmacological inactivation of CB1 receptors in NAFLD exerts multiple beneficial effects, particularly due to the attenuation of hepatic oxidative/nitrosative stress parameters and significant reduction of proinflammatory cytokine production. However, further investigations regarding precise mechanisms by which CB1 blockade influences the reduction of hepatic oxidative/nitrosative stress and inflammation are required before moving toward the clinical phase of the investigation.

Galectin-3 (Gal-3) has increasingly been recognized as a modulator of inflammation, oxidative/nitrosative stress, fibrogenesis, and tissue remodeling. The objective of the current pilot study was to investigate the influence of Gal-3 on cardiac and renal antioxidant capacity using biochemical and histopathological examinations. Two groups (n=7 each) of male mice were tested: 1. control (CON) group (wild type of C57BL/6 mice) and 2. GAL-3-/-group (galectin-3-/-knockout mice). After overnight fasting, mice were sacrificed by exsanguination in ketamine (100mg/kg intraperitoneally). Then, cardiac and renal tissue samples were taken to determine the parameters of oxidative/nitrosative stress and antioxidant capacity. The levels of malondialdehyde and nitrites+nitrates was not significantly different in the GAL-3-/-group vs. the CON group. The total superoxide dismutase activity in the renal tissue of the GAL-3-/-mice was significantly lower compared to the CON group. Cardiac and renal catalase and glutathione S-transferase activity was significantly reduced in the GAL-3-/-group vs. the CON group, respectively. A significant decrease in glutathione level was also registered in hearts of the GAL-3-/-group vs. the CON group. Our findings indicate that Gal-3 deficiency does not lead to lipid peroxidation and nitrosative stress in cardiac and renal tissue in mice. However, the lack of this beta-galactoside-binding lectin does reduce antioxidant capacity in both of the investigated tissues.

Methionine is an essential sulphur-containing amino acid involved in protein synthesis, regulation of protein function and methylation reactions. Dietary methionine restriction (0.12–0.17% methionine in food) extends the life span of various animal species and delays the onset of aging-associated diseases and cancers. In the liver, methionine restriction attenuates steatosis and delays the development of non-alcoholic steatohepatitis due to antioxidative action and metabolic reprogramming. The limited intake of methionine stimulates the fatty acid oxidation in the liver and the export of lipoproteins as well as inhibits de novolipogenesis. These effects are mediated by various signaling pathways and effector molecules, including sirtuins, growth hormone/insulin-like growth factor-1 axis, sterol regulatory element binding proteins, adenosine monophosphate-dependent kinase and general control nonderepressible 2 pathway. Additionally, methionine restriction stimulates the synthesis of fibroblast growth factor-21 in the liver, which increases the insulin sensitivity of peripheral tissues. In the brain, methionine restriction delays the onset of neurodegenerative diseases and increases the resistance to various forms of stress through antioxidative effects and alterations in lipid composition. This review aimed to summarize the morphological, functional and molecular changes in the liver and brain caused by the methionine restriction, with possible implications in the prolongation of maximal life span.