Fructose 1, 6-diphosphate prevents alcohol-induced liver injury through inhibiting oxidative stress and promoting alcohol metabolism in mice

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

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

JNK/MAPK pathway regulation by BEX2 gene silencing in alcoholic hepatitis mice: Effects on oxidative stress

BACKGROUND

Alcoholic hepatitis (AH) is a severe alcoholic-related liver disease that is a leading cause of morbidity and mortality, for which effective treatments are lacking. Brain-expressed X-linked gene 2 (BEX2) has been implicated in various diseases, but its association with AH has received limited attention. Thus, this study investigated BEX2's impact on the progression of AH by affecting the c-Jun NH2-terminal kinase/mitogen-activated protein kinase (JNK/MAPK) pathway.

METHODS

Microarray dataset GSE28619 from the Gene Expression Omnibus database was used to identify differentially expressed genes in AH. Immunohistochemistry, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), Western blot analysis, and flow cytometry were used to measure various factors in the liver tissue of AH mice.

RESULTS

BEX2 expression was significantly upregulated in the model. BEX2 gene silencing increased the levels of glutathione peroxidase and superoxide dismutase while decreasing malondialdehyde content; phosphorylation of JNK, c-JUN, and p38MAPK; apoptosis rate; and the extent of JNK/MAPK pathway activation.

CONCLUSIONS

These findings provide valuable insights into the mechanisms underlying AH development and highlight the potential role of BEX2 gene expression as a promising therapeutic target for AH.

Ameliorative effects of chlorogenic acid on alcoholic liver injury in mice via gut microbiota informatics

Chlorogenic acid (CGA) is a functional phenolic acid widely used in food and medicine-related fields. It has been proved to be effective in the treatment of alcoholic liver disease (ALD). However, the exact mechanism by which CGA prevents ALD, especially from the crosstalk between gut and liver, has not been previously reported. This work was aimed to explore the protective effects of CGA against ALD and its relationships to gut-liver axis abnormalities. Experimental results showed the increased (p < 0.05) serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), low density lipoprotein (LDL), total cholesterol (TC) and triglyceride (TG) levels of mice fed with ethanol were ameliorated by supplementing with CGA. Moreover, CGA promoted the production of n-butyric acid by nearly 3 times (1.78 vs 0.62 nM, p < 0.01), a short-chain fatty acid that helps maintain the integrity of the intestinal barrier. Furthermore, CGA alleviated microbial dysbiosis, evidenced by the increased relative abundances of beneficial bacteria Muribaculaceae, Bacteroides, Alloprevotella, and Parabacteroides, and decreased that of opportunistic pathogens Eubacterium_nodatum, Eubacterium_ruminantium, and Anaerotruncus. Correlation analysis further elucidated the microbiota altered after CGA intervention was positively correlated with short-chain fatty acids and antioxidant indexes, while negatively correlated with inflammatory cytokines. In summary, these findings suggested the hepatoprotective effect of CGA was ascribed to the modulation of gut-liver axis homeostasis.

1-O-Actylbritannilactone Ameliorates Alcohol-Induced Hepatotoxicity through Regulation of ROS/Akt/NF-κB-Mediated Apoptosis and Inflammation

1-O-Acetylbritannilactone (ABL) is a marker component of Inula britannica L. and is reported to exhibit multiple pharmacological activities, including antiaging, anti-inflammatory, and antidiabetic properties. Although the protective effect of Inula britannica L. on animal models of liver injury has been widely reported, the effect of ABL on alcohol-induced liver damage has not been confirmed. The present study was designed to investigate the protective effect of ABL against alcohol-induced LO2 human normal liver cell injury and to further clarify the underlying mechanism. Our results revealed that ABL at concentrations of 0.5, 1, and 2 μM could remarkably suppress the decreased viability of LO2 cells stimulated by alcohol. In addition, ABL pretreatment improved alcohol-induced oxidative damage by decreasing the level of reactive oxygen species (ROS) and the excessive consumption of glutathione peroxidase (GSH-Px), while increasing the level of catalase (CAT) in LO2 cells. Moreover, Western blotting analysis showed that ABL pretreatment activated protein kinase B (Akt) phosphorylation, increased downstream antiapoptotic protein Bcl-2 expression, and decreased the phosphorylation level of the caspase family including caspase 9 and caspase 3 proteins, thereby attenuating LO2 cell apoptosis. Importantly, we also found that ABL significantly inhibits the activation of the nuclear factor-kappa B (NF-κB) signaling pathway by reducing the secretion of proinflammatory factors including tumor necrosis factor-α (TNF-α) and interleukin (IL-1β). In conclusion, the current research clearly suggests that the protective effect of ABL on alcohol-induced hepatotoxicity may be achieved in part through regulation of the ROS/Akt/NF-κB signaling pathway to inhibit inflammation and apoptosis in LO2 cells. (The article path map has not been seen.).

Serum Metabolites Associated with Blood Pressure in Chronic Kidney Disease Patients

Blood pressure is one of the most basic health screenings and it has a complex relationship with chronic kidney disease (CKD). Controlling blood pressure for CKD patients is crucial for curbing kidney function decline and reducing the risk of cardiovascular disease. Two independent CKD cohorts, including matched controls (discovery n = 824; validation n = 552), were recruited. High-throughput metabolomics was conducted with the patients’ serum samples using mass spectrometry. After controlling for CKD severity and other clinical hypertension risk factors, we identified ten metabolites that have significant associations with blood pressure. The quantitative importance of these metabolites was verified in a fully connected neural network model. Of the ten metabolites, seven have not previously been associated with blood pressure. The metabolites that had the strongest positive association with blood pressure were aspartylglycosamine (p = 4.58 × 10−5), fructose-1,6-diphosphate (p = 1.19 × 10−4) and N-Acetylserine (p = 3.27 × 10−4). Three metabolites that were negatively associated with blood pressure (phosphocreatine, p = 6.39 × 10−3; dodecanedioic acid, p = 0.01; phosphate, p = 0.04) have been reported previously to have beneficial effects on hypertension. These results suggest that intake of metabolites as supplements may help to control blood pressure in CKD patients.

Effect of water-soluble propolis administration on the ethanol-induced hangover in rats

Water soluble propolis was prepared using β-cyclodextrin, and its effect on an ethanol-induced hangover was examined in Sprague-Dawley (SD) rats fed with ethanol. When SD rats were administrated with propolis 30 min after ethanol feeding, ethanol content in the rat serum decreased 2.1 times 1 h after ethanol feeding. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activity in rat liver increased 3.0 and 4.4 times, respectively, 1 h after ethanol feeding and administration of propolis 30 min after ethanol feeding. There were no differences in the expression of ADH and ALDH genes regardless of propolis administration. These results indicated that a decrease in ethanol content in the serum was not due to an increase in the expression of ADH or ALDH genes but rather, an increase in activities of ADH and ALDH.

NF-κB-mediated regulation of rat CYP2E1 by two independent signaling pathways

Cytochrome P450 2E1 (CYP2E1) plays an important role in both alcohol-induced and immune-mediated liver injury. However, the mechanism underlying CYP2E1 transcriptional regulation has not been clarified. This study focused on the NF-κB-mediated transcriptional regulation of rat CYP2E1 by two independent signaling pathways in alcohol-induced and immune-mediated liver injury rat models. Male Sprague-Dawley rats were used in pharmacokinetic, molecular pharmacology, and morphology experiments. A rat model of alcohol-induced liver injury (AL) was established by feeding an ethanol-containing diet (42 g/kg/day) for 5 weeks as indicated. A rat immune-mediated liver injury (IM) model was established by the sequential injection of bacillus Calmette-Guérin (BCG, 125 mg/kg, once) via the tail vein after test day 21 and 10 μg/kg LPS 13 days later. HPLC, real-time PCR, western blot and ELISA analyses were performed. CYP2E1 expression was enhanced during the process of alcohol-induced liver injury (increased by 56%, P < 0.05) and significantly reduced during that of immune-mediated liver injury (reducedby52%, P < 0.05). NF-κB was activated in both the AL and IM groups (increased by 56% and76%, respectively, P < 0.05). Compared to those in the livers of AL model rats, the interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and iNOS levels in IM model rat livers were increased (increased by 26%, 21% and 101%, respectively, P < 0.05). The differential changes in CYP2E1 in the processes of alcohol-induced and immune-mediated liver injury may result from the differential expression of inflammatory cytokines and iNOS after NF-κB activation, leading to the NF-κB-mediated transcriptional regulation of rat CYP2E1 by two independent signaling pathways.