Bioactive Compounds from Brown Algae Alleviate Nonalcoholic Fatty Liver Disease: An Extensive Review

Feed supplementation with the seaweed (Ascophllum Nodosum) extract reduces fat deposition in broiler chickens

In poultry industry, the strategies for elevating of protein accretion with minimizing fat deposition have been applied, and seaweed algae has been focused one of the potential candidates. Accordingly, the purpose of this study was to investigate the effects of algae (Ascophllum Nodosum) extract (AE) on the growth performance and body composition of broiler chickens. A total of 240 one-day-old Ross 308 broiler chickens were allotted to 4 dietary treatment groups and fed experimental diets containing different concentrations of AE for 35 d as follows: 0 mg/kg (control, CON), 1,250 mg/kg (LAE), 2,500 mg/kg (MAE), or 5,000 mg/kg (HAE). At the end of the experiment, 40 chickens were sacrificed and samples of their blood, breast muscle, liver, and abdominal fat were collected and analyzed. Growth performance was improved in the LAE group compared to that in the CON (P < 0.05). The weight of abdominal fat was lower in the HAE group than in the CON group (P < 0.05). Serum triglyceride levels were also decreased in the HAE group compared to those in the CON and LAE groups (P < 0.05). Adipocytes were smaller in the HAE group than in all other treatments, and their size distribution was shifted more towards smaller adipocytes compared to those in the LAE group (P < 0.05). Relative mRNA levels in abdominal adipose tissue of fatty acid synthase and stearyl-CoA desaturase, which are involved in fatty acid synthesis, were all downregulated by supplementation with AE (P < 0.05). In addition, the protein levels of peroxisome proliferator-activated receptor gamma were decreased and the ratio of phosphorylated acetyl-CoA carboxylase to total ACC was increased, both of which indicate that lipogenesis was suppressed (P < 0.05). Hepatic transcript levels of sterol regulatory element-binding protein and its downstream enzymes fatty acid synthase and sterol-CoA desaturase were also lower in all AE treatments compared to those in the CON group (P < 0.05). These results indicate that the seaweed algae (Ascophllum Nodosum) extract reduces fat accumulation in both adipose tissue and the liver by modulating lipogenesis.

Fucoxanthin Mitigates High-Fat-Induced Lipid Deposition and Insulin Resistance in Skeletal Muscle through Inhibiting PKM1 Activity

Glucose and lipid metabolism dysregulation in skeletal muscle contributes to the development of metabolic disorders. The efficacy of fucoxanthin in alleviating lipid metabolic disorders in skeletal muscle remains poorly understood. In this study, we systematically investigated the impact of fucoxanthin on mitigating lipid deposition and insulin resistance in skeletal muscle employing palmitic acid-induced lipid deposition in C2C12 cells and ob/ob mice. Fucoxanthin significantly alleviated PA-induced skeletal muscle lipid deposition and insulin resistance. In addition, fucoxanthin prominently upregulated the expression of lipid metabolism-related genes (Pparα and Cpt-1), promoting fatty acid β-oxidation metabolism. Additionally, fucoxanthin significantly increased the expression of Pgc-1α and Tfam, elevated the mtDNA/nDNA ratio, and reduced ROS levels. Further, we identified pyruvate kinase muscle isozyme 1 (PKM1) as a high-affinity protein for fucoxanthin by drug affinity-responsive target stability and LC-MS and confirmed their robust interaction by CETSA, microscale thermophoresis, and circular dichroism. Supplementation with pyruvate, the product of PKM1, significantly attenuated the beneficial effects of fucoxanthin on lipid deposition and insulin resistance. Mechanistically, fucoxanthin reduced glucose glycolysis rate and enhanced mitochondrial biosynthesis and fatty acid β-oxidation through inhibiting PKM1 activity, thereby alleviating lipid metabolic stress. These findings present a novel clinical strategy for treating metabolic diseases using fucoxanthin.

Expression and Characterization of an Efficient Alginate Lyase from Psychromonas sp. SP041 through Metagenomics Analysis of Rotten Kelp

Alginate is derived from brown algae, which can be cultivated in large quantities. It can be broken down by alginate lyase into alginate oligosaccharides (AOSs), which exhibit a higher added value and better bioactivity than alginate. In this study, metagenomic technology was used to screen for genes that code for high-efficiency alginate lyases. The candidate alginate lyase gene alg169 was detected from Psychromonas sp. SP041, the most abundant species among alginate lyase bacteria on selected rotten kelps. The alginate lyase Alg169 was heterologously expressed in Escherichia coli BL21 (DE3), Ni-IDA-purified, and characterized. The optimum temperature and pH of Alg169 were 25 °C and 7.0, respectively. Metal ions including Mn2+, Co2+, Ca2+, Mg2+, Ni2+, and Ba2+ led to significantly increased enzyme activity. Alg169 exhibited a pronounced dependence on Na+, and upon treatment with Mn2+, its activity surged by 687.57%, resulting in the highest observed enzyme activity of 117,081 U/mg. Bioinformatic analysis predicted that Alg169 would be a double-domain lyase with a molecular weight of 65.58 kDa. It is a bifunctional enzyme with substrate specificity to polyguluronic acid (polyG) and polymannuronic acid (polyM). These results suggest that Alg169 is a promising candidate for the efficient manufacturing of AOSs from brown seaweed.

Very low-carbohydrate diet with higher protein ratio improves lipid metabolism and inflammation in rats with diet-induced nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is commonly associated with obesity, and it is mainly treated through lifestyle modifications. The very low-carbohydrate diet (VLCD) can help lose weight rapidly but the possible effects of extreme dietary patterns on lipid metabolism and inflammatory responses in individuals with NAFLD remain debatable. Moreover, VLCD protein content may affect its effectiveness in weight loss, steatosis, and inflammatory responses. Therefore, we investigated the effects of VLCDs with different protein contents in NAFLD rats and the mechanisms underlying these effects. After a 16-week inducing period, the rats received an isocaloric normal diet (NC group) or a VLCD with high or low protein content (NVLH vs. NVLL group, energy ratio:protein/carbohydrate/lipid=20/1/79 vs. 6/1/93) for the next 8 weeks experimental period. We noted that the body weight decreased in both the NVLH and NVLL groups; nevertheless, the NVLH group demonstrated improvements in ketosis. The NVLL group led to hepatic lipid accumulation, possibly by increasing very-low-density lipoprotein receptor (VLDLR) expression and elevating liver oxidative stress, subsequently activating the expression of Nrf2, and inflammation through the TLR4/TRIF/NLRP3 and TLR4/MyD88/NF-κB pathway. The NVLH was noted to prevent the changes in VLDLR and the TLR4-inflammasome pathway partially. The VLCD also reduced the diversity of gut microbiota and changed their composition. In conclusion, although low-protein VLCD consumption reduces BW, it may also lead to metabolic disorders and changes in microbiota composition; nevertheless, a VLCD with high protein content may partially alleviate these limitations.

Integrative proteomics and metabolomics explore the effect and mechanism of Qiyin granules on improving nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as a prominent global health concern, representing a substantial burden within the spectrum of chronic liver diseases. Despite its escalating prevalence, a definitive therapeutic strategy or efficacious pharmacological intervention for NAFLD has yet to receive official approval to date. While Fu Fang Qiyin granules have exhibited efficacy in addressing NAFLD, the intricacies of their underlying mechanism of action remain inadequately elucidated. In this study, we substantiated the ameliorative impact of Qiyin on highfat diet (HFD)induced NAFLD in rat models. The results of metabonomics showed that 108 potential biomarkers in serum and urine related to amino acid metabolism, energy metabolism, and pyrimidine metabolism, have returned to normal levels compared to the model group. Hepatic transcriptomics further indicated that Qiyin potentially confers protective effects against NAFLD by mediating liver inflammation and fibrosis through lumican (LUM) and decorin (DCN). In summation, our investigation provides compelling evidence affirming the therapeutic promise of Qiyin for NAFLD. It elucidates the underlying mechanistic pathways, furnishing a compelling rationale for its prospective clinical application.

Laminaria japonica Aresch-Derived Fucoidan Ameliorates Hyperlipidemia by Upregulating LXRs and Suppressing SREBPs

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, and hyperlipidemia is one major inducing factor of CVD. It is worthy to note that fucoidans are reported to have hypolipidemic activity with species specificity; however, the underlying mechanisms of action are far from clarification. This study is aimed at investigating the plasma lipid-lowering mechanisms of the fucoidan from L. japonica Aresch by detecting the levels of hepatic genes that are involved in lipid metabolism. Our results demonstrated that the fucoidan F3 significantly lowered total cholesterol and triglyceride in C57BL/6J mice fed a high-fat diet. In the mouse liver, fucoidan F3 intervention significantly increased the gene expression of peroxisome proliferator-activated receptor (PPAR) α, liver X receptor (LXR) α and β, and ATP-binding cassette transporter (ABC) G1 and G8 and decreased the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), low-density lipoprotein receptor, cholesterol 7 alpha-hydroxylase A1, and sterol regulatory element-binding protein (SREBP) 1c and SREBP-2. These results demonstrated that the antihyperlipidemic effects of fucoidan F3 are related to its activation of PPARα and LXR/ABC signaling pathways and inactivation of SREBPs. In conclusion, fucoidan F3 may be explored as a potential compound for prevention or treatment of lipid disorders.