Hepatoprotective Potential of Partially Hydrolyzed Guar Gum against Acute Alcohol-Induced Liver Injury in Vitro and Vivo

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.

Glucosamine attenuates alcohol-induced acute liver injury via inhibiting oxidative stress and inflammation

Alcohol liver disease (ALD) is a liver disease caused by long-term heavy drinking. Glucosamine (GLC) is an amino monosaccharide that plays a very important role in the synthesis of human and animal cartilage. GLC is commonly used in the treatment of mild to moderate osteoarthritis and has good anti-inflammatory and antioxidant properties. In this study, alcoholic injury models were constructed in mice and human normal hepatocyte L02 cells to explore the protective effect and mechanism of GLC on ALD. Mice were given GLC by gavage for 30 days. Liver injury models of both mice and L02 cells were produced by ethanol. Detecting the levels of liver injury biomarkers, lipid metabolism, oxidative stress biomarkers, and inflammatory factors through different reagent kits. Exploring oxidative and inflammatory pathways in mouse liver tissue through Western blot and RT-PCR. The results showed that GLC can significantly inhibit the abnormal increase of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), triglycerides (TG), total cholesterol (TC), very low density lipoprotein (VLDL), low-density lipoprotein cholesterol (LDL-C), and can significantly improve the level of high-density lipoprotein cholesterol (HDL-C). In addition, GLC intervention significantly improved alcohol induced hepatic oxidative stress by reducing the levels of malondialdehyde (MDA) and, increasing the levels of glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) in the liver. Further mechanisms suggest that GLC can inhibit the expression of ethanol metabolism enzyme cytochrome P4502E1 (CYP2E1), activate the antioxidant pathway Keap1/Nrf2/HO-1, down-regulate the phosphorylation of MAPK and NF-κB signaling pathways, and thus reduce the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Therefore, GLC may be a significant candidate functional food for attenuating alcohol induced acute liver injury.

Effect of natural polysaccharides on alcoholic liver disease: A review

In this study, we systematically collected relevant literature in the past five years on the intervention of natural polysaccharides in alcoholic liver disease (ALD) and reviewed the pharmacological activities and potential mechanisms of action. Natural polysaccharides are effective in preventing liver tissue degeneration, inhibiting the alcohol-induced expression of inflammatory factors, inactivation of antioxidant enzymes, and abnormal hepatic lipid deposition. Natural polysaccharides regulate the expression of proteins, such as tight junction proteins, production of small molecule metabolites, and balance of intestinal flora in the intestinal tract to alleviate ALD. Natural polysaccharides also exert therapeutic effects by modulating inflammatory, oxidative, lipid metabolism, and other pathways in the liver. Natural polysaccharides also inhibit alcohol-induced intestinal abnormalities by regulating intestinal flora and feeding back into the liver via the gut-liver axis. However, existing research on natural polysaccharides has many shortcomings: for example, most of the natural polysaccharides for testing are total polysaccharides or crude polysaccharides, progress in research on in vivo metabolic processes and mechanisms is slow, and the degree of industrialisation is insufficient. Finally, we discuss the difficulties in studying natural polysaccharides and future directions to provide a theoretical basis for their development and application.

Regulation of NOX/p38 MAPK/PPARα pathways and miR-155 expression by boswellic acids reduces hepatic injury in experimentally-induced alcoholic liver disease mouse model: novel mechanistic insight

Alcoholic liver disease (ALD) refers to hepatic ailments induced by excessive alcohol intake. The pathogenesis of ALD comprises a complex interplay between various mechanistic pathways, among which inflammation and oxidative stress are key players. Boswellic acids (BAs), found in Boswellia serrata, have shown hepatoprotective effects owing to their antioxidant and anti-inflammatory activities, nevertheless, their therapeutic potential against ALD has not been previously investigated. Hence, this study was performed to depict the possible protective effect of BAs and detect their underlying mechanism of action in an experimentally-induced ALD mouse model. Male BALB/c mice were equally categorized into six groups: control, BAs-treated, ALD, and ALD that received BAs at three-dose levels (125, 250, and 500 mg/kg) by oral gavage for 14 days. Results showed that the high dose of BAs had the most protective impact against ALD according to histopathology examination, blood alcohol concentration (BAC), and liver function enzymes. Mechanistic investigations revealed that BAs (500 mg/kg) caused a significant decrease in cytochrome P450 2E1(CYP2E1), nicotine adenine dinucleotide phosphate oxidase (NOX) 1/2/4, p38 mitogen-activated protein kinase (MAPK), and sterol regulatory element-binding protein-1c (SREBP-1c) levels, and the expression of miR-155, yet increased peroxisome proliferator-activated receptor alpha (PPARα) levels. This led to an improvement in lipid profile and reduced hepatic inflammation, oxidative stress, and apoptosis indices. In summary, our study concludes that BAs can protect against ethanol-induced hepatic injury, via modulating NOX/p38 MAPK/PPARα pathways and miR-155 expression.

Oenothein B ameliorates hepatic injury in alcoholic liver disease mice by improving oxidative stress and inflammation and modulating the gut microbiota

Introduction

Alcoholic liver disease (ALD) is a global health problem for which there is no current food and drug administration (FDA)-approved therapy. Oenothein B (OEB) is a macrocyclic dimer ellagic tannin that possesses abundant biological activities including antioxidant, anti-inflammation, antitumor, immunomodulatory, and antimicrobial properties.

Materials and methods

In this study, the hepatoprotective effect of OEB against ALD was investigated in vivo and in vitro.

Results

We found that OEB treatment dramatically reduced alcohol-induced hepatic injury, as evidenced by decreased levels of aminotransferases and inflammatory biomarkers and increased antioxidant capacity in OEB-treated groups.

Discussion

OEB treatment alleviated oxidative stress by upregulating the Keap1/Nrf2 signaling pathway and inhibited inflammation by downregulating the TLR4/NF-κB signaling pathway. Additionally, OEB treatment positively improved alcohol-induced intestinal microbial dysbiosis by modulating the structure and composition of gut microbiota. Interestingly, we observed the increasement of short-chain fatty acid (SCFA) producers (Muribaculaceae) and the decreasement of Gram-negative bacteria (Akkermansia) in the OEB treatment groups, which may contribute to the inhibition of hepatic oxidative stress and inflammation via the gut-liver axis. In summary, our findings indicate that OEB is a promising therapeutic strategy for preventing and treating ALD.

Partially hydrolyzed guar gum alleviates hepatic steatosis and alters specific gut microbiota in a murine liver injury model

PURPOSE

The gut microbiota, via the gut-liver axis, plays an important role in the development of intestinal failure-associated liver disease. Here, we investigated whether partially hydrolyzed guar gum (PHGG), a dietary fiber could alleviate liver damage and modulate the gut microbiota in a murine liver injury (LI) model.

METHODS

Liver injury was induced in 6-week-old male C57BL/6 mice using an enteral liquid diet composed of parenteral nutrition (LI group) and treated with 5% PHGG (LI/PHGG group). Liver histopathology was examined using oil red O and a tumor necrosis factor-α (TNF-α) labeling. The gut microbiota was examined using 16S rRNA gene sequencing.

RESULTS

Lipid accumulation was significantly decreased in the LI /PHGG group when compared with that of the LI group. The area of TNF-α-positive cells was significantly higher in the LI group when compared with that of the control. The principal coordinate analysis (PCoA) revealed pronounced changes in the gut microbiota after PHGG treatment. Linear discriminant analysis of effect size showed that PHGG treatment significantly increased cecal abundance of Parabacteroides.

CONCLUSIONS

PHGG alleviated hepatic steatosis following liver injury in mice. The protective effect of PHGG treatment could be associated with increased abundance of Parabacteroides in the cecum.

Optimization and Application of A Bionic System of Dynamic Co-Culture with Hepatocytes and Renal Cells Based on Microfluidic Chip Technique in Evaluating Materials of Health Food

We aimed to explore the optimization and application of a bionic system of dynamic co-culture with hepatocytes and renal cells based on the microfluidic chip technique in evaluating emodin, which might replace the conventionally cytological evaluation technique of health food. After optimal experiments, the improved bionic system was composed of human hepatocellular carcinoma cells (HepG2), human renal glomerular endothelial cells (HRGECs), rat tail collagen type I, and gelatin with optimized concentrations (1.3 mg/mL + 7.5%). The applicability of the bionic system indicated that the growth stability was appropriate (CV: 7.36%), and the cell viability of that gradually decreased with the increasing of emodin concentration from 0−100 μM, which statistic significances were at 50 and 100 μM (p < 0.05), and the stained results of dead/live cells also showed the same trend. The LDH level appeared rising trend after decline between 0 μM and 100 μM emodi, and the level of that at 100 μM emodin was significantly higher than that at 25 μM and 50 μM emodin, respectively. The BUN level continuously and significantly declined with the increasing of emodin concentration (p < 0.05). Our research realized the application of this optimized bionic system in evaluating emodin, and provided a useful platform and reference for further in vitro alternative research with regard to evaluating the efficacies of health food in the future.

Galacto-Oligosaccharide Alleviates Alcohol-Induced Liver Injury by Inhibiting Oxidative Stress and Inflammation

Alcoholic liver disease (ALD) is a primary cause of mortality and morbidity worldwide. Oxidative stress and inflammation are important pathogenic factors contributing to ALD. We investigated the protective mechanism of galacto-oligosaccharide (GOS) against ALD through their antioxidant and anti-inflammatory activities by performing in vivo and in vitro experiments. Western blot and RT‒PCR results indicated that the expression of cytochrome P450 protein 2E1 (CYP2E1) in liver tissues and L02 cells was reduced in the GOS-treated mice compared with the model group. In addition, GOS prominently reduced the expression of Kelch-like ECH-associated protein 1 (Keap1), increased the expression of the nuclear factor erythroid-2-related factor 2 (Nrf2) and haem oxygenase-1 (HO-1) proteins, and enhanced the antioxidant capacity. In addition, GOS decreased inflammation by reducing inflammatory factor levels and inhibiting the mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) pathway. Based on these results, GOS may be a prospective functional food for the prevention and treatment of ALD.

Interaction between polysaccharides and toll-like receptor 4: Primary structural role, immune balance perspective, and 3D interaction model hypothesis

Various structural types of polysaccharides are recognized by toll-like receptor 4 (TLR4). However, the mechanism of interaction between the polysaccharides with different structures and TLR4 is unclarified. This review summarized the primary structure of polysaccharides related to TLR4, mainly including molecular weight, monosaccharide composition, glycosidic bonds, functional groups, and branched-chain structure. The optimal primary structure for interacting with TLR4 was obtained by the statistical analysis. Besides, the dual-directional regulation of TLR4 signaling cascade by polysaccharides was also elucidated from an immune balance perspective. Finally, the 3D interaction model of polysaccharides to TLR4-myeloid differentiation factor 2 (MD2) complex was hypothesized according to the LPS-TLR4-MD2 dimerization model and the polysaccharides solution conformation. The essence of polysaccharides binding to TLR4-MD2 complex is a multivalent non-covalent bond interaction. All the arguments summarized in this review are intended to provide some new insights into the interaction between polysaccharides and TLR4.

The in vitro and in vivo Antioxidant and Immunomodulatory Activity of Incomplete Degradation Products of Hemicellulosic Polysaccharide (Galactomannan) From Sesbania cannabina

As known, the nutritional status affects antioxidant capacity and immunity, ultimately affecting the body’s health. Recently, hemicellulosic polysaccharides of galactomannan in different biomass and their degradation products are gaining more attention due to excellent antioxidant enhancement and immunomodulatory activity. Herein, incomplete degradation products of galactomannan (IDPG) were prepared from the enzymatic hydrolysis of Sesbania cannabina seeds, followed by the in vitro and in vivo experiments. Using an H₂O₂-injured RAW264.7 cells model, IDPG was demonstrated to have antioxidant capacity, as indicated by superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. While in the evaluation in laying hens (68-weeks-old), diets were supplemented with 0, 0.01, 0.025, and 0.05% IDPG for 8 weeks, respectively. Our results showed that IDPG can improve antioxidant capacity by increasing antioxidants contents and reducing MDA content. Furthermore, IDPG can increase immunoglobulins and cytokines secretion, thereby enhancing the immunity of laying hens. This result was further demonstrated by in vitro experiment, in which IDPG significantly increased the secretion of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and toll-like receptor 4 (TLR4) in RAW264.7 cells (P < 0.05). Overall, IDPG can improve antioxidant function and modulate immunological response, thereby the concept of using IDPG for health may gain a little more credibility.

Functional hydrocolloids, gut microbiota and health: picking food additives for personalized nutrition

The human gut microbiota respond to particular food components, interact with intestinal mucosa and thereby contribute to health and diseases. Key microbiome features are under comprehensive investigation and are likely to be developed as reliable evidences for clinical diagnosis. And the underlying mechanisms lay the foundation of assembling bespoke nutritional ingredients including functional food additives that may lead to favorable outcomes in facilitating amelioration of host dysfunctions. Functional hydrocolloids serve as multiple food additives with promising application prospects and outstanding adjunctive beneficial characteristics. Therefore, in this review, we introduce the latest advances in food additives-gut microbiota-host axis by summarizing the physiochemical and physiological properties of a collection of functional hydrocolloids from various sources, describing the functional hydrocolloids-related intestinal commensal markers, and deciphering the underlying mechanisms of their beneficial effects, and propose the feasibilities and guidelines for further developments of gut microbiota-oriented personalized nutrition.

Hepatoprotection mechanism against alcohol-induced liver injury in vivo and structural characterization of Pinus koraiensis pine nut polysaccharide

Previous studies have shown that Pinus koraiensis pine nut polysaccharide PNP80b-2 exerts widely protective effects against liver injury induced by chemical pollutants, alcohol and drugs. By comparison, PNP80b-2 exhibits the strongest hepatoprotection against alcohol-induced liver injury (AILI). Thus, the purpose of this study is to investigate the hepatoprotection mechanisms of PNP80b-2 against AILI in vivo. The results indicated that PNP80b-2 alleviated oxidative stress induced by alcohol through enhancing antioxidant capacity of hepatocytes via NRF2/HO-1 pathway. PNP80b-2 also effectively suppressed the secretion of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6, exhibiting anti-inflammatory effects via NF-κB signaling pathway in AILI. In addition, PNP80b-2 protected mice from severe DNA damage induced by alcohol through regulating the expression of Hipk2, P53, Hp1γ and Wip1. Taken together all the results, PNP80b-2 exerts hepatoprotective activity against AILI in vivo through enhancing antioxidant capacity, suppressing inflammation response and promoting DNA damage repair in livers. Furthermore, the structural features of PNP80b-2 were also characterized. PNP80b-2, with molecular weight of 23.0 kDa, was found to be composed of 1,2-linked Galf, 1,2-linked Rhap, 1,4-linked Xylp, 1,6-linked Glcp, 1,4-linked GlcpA, 1,2,6-linked Galp, 1,4,6-linked Glcp, 1,2,3,4-linked Arap, 1-linked Galp and Leu- and Ile-linked O-glycopeptide bonds, based on the GC-MS and NMR results.

Astaxanthin from Haematococcus pluvialis ameliorates the chemotherapeutic drug (doxorubicin) induced liver injury through the Keap1/Nrf2/HO-1 pathway in mice

The aim of this study is to probe a new function of astaxanthin (AST) from Haematococcus pluvialis on chemotherapeutic drug (doxorubicin) induced liver injury in mice.

Comparative study on hepatoprotection of pine nut (Pinus koraiensis Sieb. et Zucc.) polysaccharide against different types of chemical-induced liver injury models in vivo

A novel polysaccharide (PNP80b-2) was obtained from Pinus koraiensis pine nut, which has been proved to possess good hepatoprotective effects in vitro. This study comprehensively investigated its hepatoprotective activities against different types of chemical-induced liver injury in vivo. Carbon tetrachloride, alcohol and acetaminophen were used as hepatic toxicants to establish chemical pollutant-induced liver injury (CILI) model, alcohol induced-liver injury (AILI) model and drug-induced liver injury (DILI) model, respectively. The results showed that PNP80b-2 prevented elevation of biomarkers for liver injury in each model, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bilirubin (TBIL). The expression of cytochrome P450 in damaged hepatocytes was also downregulated. Additionally, PNP80b-2 enhanced hepatic antioxidant capacity through upregulating the expression of NRF2 and HO-1, thereby increasing superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities and decreasing malondialdehyde (MDA) levels. The uncontrolled production of inflammatory factors including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2) in CILI, AILI and DILI models was also suppressed by PNP80b-2. By contrast, PNP80b-2 exerted the strongest hepatoprotection against AILI model, through improving hepatic antioxidant capacity via NRF2/ARE pathway and regulating inflammation response. Thus, PNP80b-2 is a promising functional food to prevent AILI.