Improvement of liver function by the administration of oyster extract as a dietary supplement to habitual alcohol drinkers: A pilot study

Hepatoprotective Effect of Oyster Peptide on Alcohol-Induced Liver Disease in Mice

Alcohol-induced liver disease (ALD) has become one of the major global health problems, and the aim of this study was to investigate the characterization of the structure as well as the hepatoprotective effect and mechanism of oyster peptide (OP, MW < 3500 Da) on ALD in a mouse model. The results demonstrate that ethanol administration could increase the activities of aspartate aminotransferase (AST), alanine transaminase (ALT), γ-Glutamyl transferase (GGT), reactive oxygen species (ROS), malondialdehyde (MDA), and triglycerides (TG), as well as increase the interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor (TNF-α) levels (p < 0.01), and reduce the activity of superoxide dismutase (SOD) and the concentration of glutathione (GSH). Those changes were significantly reversed by the application of different doses of OP. Furthermore, the mRNA expressions of nuclear factor elythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and quinone oxidoreductase1 (NQO1) were significantly up-regulated in OP groups, and the mRNA expressions of nuclear factor kappa-light chain enhancer of B cells (NF-κB), TNF-α, and IL-6 were markedly reduced in OP groups compared to that of the model group. Thus, OP had a significant protective effect on ALD through the enhancement of the in vivo antioxidant ability and the inhibition of the inflammatory response as possible mechanisms of action, which therefore suggests that OP might be useful as a natural source to protect the liver from alcohol damage.

Protective effects of oyster protein hydrolysates on alcohol-induced liver disease (ALD) in mice: based on the mechanism of anti-oxidative metabolism

Many bioactivities of hydrolysates from oyster (Crassostrea gigas) muscle have been reported, while there is no knowledge about their protective effects on alcohol-induced liver disease (ALD). In the present study, the anti-oxidative activities in vitro and molecular weight distribution of oyster protein hydrolysates (OPH) were detected and the OPH released by alcalase (AOPH) was used to treat C57BL/6 mice. C57BL/6 mice were treated with a Lindros control diet to establish an ethanol-exposed model. The content of small-weight components (<2.0 kDa) of OPH reached 90.85%. AOPH showed more potent antioxidant activities in vitro with higher reducing power and ferric reducing antioxidant power (FRAP), and those capacities could be maintained at a high level after simulated gastrointestinal digestion. Compared to the model mice, oral administration (4 weeks) of AOPH at 800 mg per kg body weight could lead to a decline in T-AOC, GSH-PX, and ADH in the liver. The hepatocellular lesions were effectively relieved and impaired liver tissue development was successfully inhibited. A total of 834 genes and 54 proteins showed differential expression in the AOPH group and the oxidative metabolic pathways of ethanol such as oxidative phosphorylation, glutathione metabolism, peroxisomes, the PPAR signaling pathway and drug metabolism-cytochrome P450 play a preeminent role in ALD according to the results of transcriptomics and proteomics. The beneficial effects of AOPH were available in the improvement of ALD. These results revealed that AOPH intervention ameliorated ALD by affecting oxidative metabolism and highlighting AOPH's potential application as a functional food.

Dipeptide YA is Responsible for the Positive Effect of Oyster Hydrolysates on Alcohol Metabolism in Single Ethanol Binge Rodent Models

Accumulative alcohol hangovers cause liver damage through oxidative and inflammatory stress. Numerous antioxidant and anti-inflammatory reagents have been developed to reduce alcohol hangovers, but these reagents are still insignificant and have limitations in that they can cause liver toxicity. Oyster hydrolysate (OH), another reagent that has antioxidant and anti-inflammatory activity, is a product extracted through an enzymatic hydrolysis process from oysters (Crassostrea gigas), which can be easily eaten in meals. This study was aimed at determining the effects of OH on alcohol metabolism, using a single high dose of ethanol (EtOH) administered to rodents, by monitoring alcohol metabolic enzymes, oxidative stress signals, and inflammatory mediators. The effect of tyrosine-alanine (YA) peptide, a main component of OH, on EtOH metabolism was also identified. In vitro experiments showed that OH pretreatment inhibited EtOH-induced cell death, oxidative stress, and inflammation in liver cells and macrophages. In vivo experiments showed that OH and YA pre-administration increased alcohol dehydrogenase, aldehyde dehydrogenase, and catalase activity in EtOH binge treatment. In addition, OH pre-administration alleviated CYP2E1 activity, ROS production, apoptotic signals, and inflammatory mediators in liver tissues. These results showed that OH and YA enhanced EtOH metabolism and had a protective effect against acute alcohol liver damage. Our findings offer new insights into a single high dose of EtOH drinking and suggest that OH and YA could be used as potential marine functional foods to prevent acute alcohol-induced liver damage.

miR‑148a‑3p regulates alcoholic liver fibrosis through targeting ERBB3

Alcoholic liver disease greatly affects human health. Previous studies have identified that microRNAs (miRNAs) are associated with the pathogenesis of alcoholic liver fibrosis (ALF). Therefore, the present study explored the regulatory mechanism of miR-148a-3p in ALF. An ALF model was established in rats by alcohol gavage, followed by treatment with miR-148a-3p. Reverse transcription-quantitative (RT-q) PCR was performed to detect miR-148a-3p expression in the rat liver tissues. The levels of lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) were determined by enzyme-labeled colorimetry. Liver damage was evaluated by liver indices and histology. The direct target gene of miR-148a-3p was predicted by a dual luciferase reporter assay. The effects of miR-148a-3p and miR-148a-3p in combination with receptor tyrosine-protein kinase erbB-3 (ERBB3) on HSC-T6 cell viability and apoptosis were detected by MTT and flow cytometry assays, respectively. Western blotting and RT-qPCR assays were performed to detect the expression levels of proteins and mRNA associated with fibrosis and apoptosis. The data showed that miR-148a-3p mimics inhibited the expression levels of AST, ALT, ALP, LDH, α-SMA and type I collagen in the model, decreased the liver indices, and improved the liver damage caused by alcohol. ERBB3, which was predicted as the direct target gene of miR-148a-3p, reversed the effects of ERBB3 on promoting cell viability and inhibiting apoptosis. Concomitantly, miR-148a-3p reversed the increased expression of Bcl-2 and inhibited the expression levels of Bax and c-cleaved-3 caused by ERBB3. These data suggested that miR-148a-3p regulated ALF and the viability and apoptosis of hepatic stellate cells through targeting ERBB3.