Fatty liver diseases, mechanisms, and potential therapeutic plant medicines

Structure characteristics of a novel pectic polysaccharide from Fructus Corni and its protective effect on alcoholic fatty liver

Alcoholic fatty liver disease (AFLD) is characterized by the accumulation of hepatic lipid and has no effective treatment yet. Fructus Corni is a traditional Chinese medicinal herb, and its extractions have demonstrated hepatoprotective properties. We hypothesize that the polysaccharides in Fructus Corni might have therapeutic effects on AFLD. In this study, we isolated a novel homogeneous polysaccharide, APFC-2 (Mw= 63.0 kDa), from the Fructus Corni, and its structure was elucidated by monosaccharide composition, methylation analysis, partial acid hydrolysis, and NMR spectra. APFC-2 is a pectic polysaccharide characterized by a backbone of T-β-Galp-(1 → 6)-β-Galp-(1 → 3,6)-β-Galp-(1 → [4)-α-GalpA-OMe-(1 → 4)-α-GalpA-(1→]m → [2,4)-α-Rhap-(1 → 4)-α-GalpA-(1→]n, with branches comprising T-Araf-(1→, →3)-α-Araf-(1→, →3,5)-α-Araf-(1→, and →5)-α-Araf-(1→. In vivo experiments indicated that APFC-2 could significantly reduce hepatic steatosis, fasting triglyceride, and cholesterol levels in AFLD mice. Cell proliferation and Oil Red O staining results showed that APFC-2 concentration-dependently increased cell viability and significantly improved lipid metabolism in vitro. Mechanistically, APFC-2 markedly inhibited the formation of lipid both in vitro and in vivo through activating liver kinase B1 (LKB1) and then regulating adenosine 5'-monophosphate-activated protein kinase (AMPK)-SREBP-1 and AMPK-PPAR-α pathways. This research provides a theoretical basis for the potential application of Fructus Corni pectic polysaccharide as a specific activator of LKB1 for treating AFLD.

Effect of soluble dietary fiber extracted from Lentinula edodes (Berk.) Pegler on lipid metabolism and liver protection in mice on high-fat diet

With the increasing annual production of Lentinula edodes, the residues of Lentinus edodes are mass produced and wasted every year. In order to further explore the added value and effective utilization of Lentinus edodes, we studied the lipid-lowering efficacy and liver protective effect of Lentinus edodes soluble dietary fiber in mice on high-fat diet. Project team from Lentinus edodes extracted soluble dietary fiber, and its physicochemical properties, selected 30 male mice, randomly divided into normal group (N), high fat diet group (F), add low dose dietary fiber high fat diet (FL), add medium dose dietary fiber high fat diet group (FM), add high dose dietary fiber high fat diet group (FH) five groups. After 4 weeks, we assessed general state, organ conditions, liver status, blood parameters, expression of hepatic lipid metabolism genes, mRNA levels of key hepatic lipid metabolism genes. The results showed that the molecular weight of soluble dietary fiber is about 17.029 kDa, and the monosaccharides such as galactose, glucose and mannitol are connected by β-glycosidic bond. The soluble dietary fiber of Lentinus edodes can effectively slow the weight growth due to high-fat diet, delay liver tissue lesions, reduce the levels of ALT, AST, ACP, LDL-C, TG, TV, FFA, SOD, GSH and MDA, and increase the levels of γ-GT, HDL-C and CAT in blood. Lentinus edodes soluble dietary fiber decreased the expression of AMPKα and SREBP-2 in the liver, and increased the expression of PPARα, ACS, CPT1a, CYP7A1. It is proved that the soluble dietary fiber of Lentinus edodes can alleviate the organ fat accumulation caused by high-fat diet to some extent, effectively combat the liver injury, oxidative stress pressure and lipid metabolism disorder caused by high-fat diet, and provide an experimental basis for the subsequent effective use of soluble dietary fiber of Lentinus edodes in fat reduction.

Betaine Suppresses Lipid Accumulation in Liver: Inhibition of FoxO6 and PPARγ Interaction

Betaine is the major water-soluble component of Lycium chinensis. Although there are reports of a protective effect of betaine on fatty liver disease, the underlying mechanisms are unclear. We attempted to elucidate the molecular regulation of betaine on hyperglycemia-induced hepatic lipid accumulation via Forkhead box O (FoxO)6 activation. HepG2 cells and liver tissue isolated from db/db mice treated with betaine were used. The present study investigated whether betaine ameliorates hepatic steatosis by inhibiting FoxO6/peroxisome proliferator-activated receptor gamma (PPARγ) signaling in liver cells. Interestingly, betaine notably decreased lipid accumulation in tissues with FoxO6-induced mRNA expression of lipogenesis-related genes. Furthermore, betaine inhibited the FoxO6 interaction with PPARγ and cellular triglycerides in high-glucose- or FoxO6-overexpression-treated liver cells. In addition, we confirmed that betaine administration via oral gavage significantly ameliorated hepatic steatosis in db/db mice. We conclude that betaine ameliorates hepatic steatosis, at least in part, by inhibiting the interaction between FoxO6 and PPARγ, thereby suppressing lipogenic gene transcription.

Forkhead box O1 in metabolic dysfunction-associated fatty liver disease: molecular mechanisms and drug research

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a chronic liver disease that progresses from hepatic steatosis to non-alcoholic steatohepatitis, cirrhosis, and liver cancer, posing a huge burden on human health. Existing research has confirmed that forkhead box O1 (FOXO1), as a member of the FOXO transcription factor family, is upregulated in MAFLD. Its activity is closely related to nuclear-cytoplasmic shuttling and various post-translational modifications including phosphorylation, acetylation, and methylation. FOXO1 mediates the progression of MAFLD by regulating glucose metabolism, lipid metabolism, insulin resistance, oxidative stress, hepatic fibrosis, hepatocyte autophagy, apoptosis, and immune inflammation. This article elaborates on the regulatory role of FOXO1 in MAFLD, providing a summary and new insights for the current status of drug research and targeted therapies for MAFLD.

Shuangyu Tiaozhi decoction alleviates non-alcoholic fatty liver disease by improving lipid deposition, insulin resistance, and inflammation in vitro and in vivo

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. Our previous studies have found that Shuangyu Tiaozhi Decoction (SYTZD) could produce an improvement in NAFLD-related indicators, but the underlying mechanism associated with this improvement remains unclear. The study aimed to investigate the potential mechanism of SYTZD against NAFLD through network pharmacology and experimental verification. The components of SYTZD and SYTZD drug containing serum were analyzed using ultra-performance liquid chromatography to quadrupole/time-of-flight mass spectrometry (UPLC-Q/TOF-MS). Active components and targets of SYTZD were screened by the traditional Chinese medical systems pharmacology (TCMSP) and encyclopedia of traditional Chinese medicine (ETCM) databases. NAFLD-related targets were collected from the GeneCards and DisGeNET databases. The component-disease targets were mapped to identify the common targets of SYTZD against NAFLD. Protein-protein interaction (PPI) network of the common targets was constructed for selecting the core targets. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the core targets was performed using the database for annotation, visualization, and integrated discovery (DAVID) database. Furthermore, animal and cell models were constructed for validating the predictions of network pharmacology. Lipid accumulation, liver histopathology, insulin resistance, and core gene expression were measured by oil red O staining, hematoxylin and eosin staining, insulin tolerance test, real-time quantitative polymerase chain reaction, and Western blotting, respectively. Two components and 22 targets of SYTZD against NAFLD were identified by UPLC-Q/TOF-MS and relevant databases. PPI analysis found that ESR1, FASN, mTOR, HIF-1α, VEGFA, and GSK-3β might be the core targets of SYTZD against NAFLD, which were mainly enriched in the thyroid hormone pathway, insulin resistance pathway, HIF-1 pathway, mTOR pathway, and AMPK pathway. Experimental results revealed that SYTZD might exert multiple anti-NAFLD mechanisms, including improvements in lipid deposition, inflammation, and insulin resistance. SYTZD treatment led to decreases in the lipid profiles, hepatic enzyme levels, inflammatory cytokines, and homeostatic model assessment for insulin resistance (HOMA-IR). SYTZD treatment affected relative mRNA and protein levels associated with various pathways. Our findings reveal that SYTZD could alleviate NAFLD through a multi-component, multi-target, and multi-pathway mechanism of action.

Protective Effect and Mechanism of Plant-Based Monoterpenoids in Non-alcoholic Fatty Liver Diseases

The protective effect of plant active ingredients against non-alcoholic fatty liver disease (NAFLD) is becoming increasingly prominent, and the terpenoids have always been the main active compounds in Chinese herbal medicine exerting hepatoprotective effects. However, the related pharmacological effects, especially for monoterpenoids or iridoid glycosides, which have obvious effects on improvement of NAFLD, have not been systematically analyzed. The objective of this review is to systematically examine the molecular mechanisms of monoterpenoids in NAFLD. The signaling pathways of peroxisome proliferator-activated receptor, insulin, nuclear factor κB, toll-like receptor, adipocytokine, RAC-α serine/threonine protein kinase, mammalian target of rapamycin, 5'-AMP-activated protein kinase, and autophagy have been proven to mediate this protective effect. We further compared the experimental data from animal models, including the dosage of these monoterpenoids in detail, and demonstrated that they are effective and safe candidate drugs for NAFLD. This review provides a reference for the development of NAFLD drugs as well as a research guideline for the potential uses of plant monoterpenoids.

Bile Acids, Gut Microbiome and the Road to Fatty Liver Disease

This article describes the complex interactions occurring between diet, the gut microbiome, and bile acids in the etiology of fatty liver disease. Perhaps 25% of the world's population may have nonalcoholic fatty liver disease (NAFLD) and a significant percentage (∼20%) of these individuals will progress to nonalcoholic steatohepatitis (NASH). Currently, the only recommended treatment for NAFLD and NASH is a change in diet and exercise. A Western-type diet containing high fructose corn syrup, fats, and cholesterol creates gut dysbiosis, increases intestinal permeability and uptake of LPS causing low-grade chronic inflammation in the body. Fructose is a "lipogenic" sugar that induces long-chain fatty acid (LCFA) synthesis in the liver. Inflammation decreases the oxidation of LCFA, allowing fat accumulation in hepatocytes. Hepatic bile acid transporters are downregulated by inflammation slowing their enterohepatic circulation and allowing conjugated bile acids (CBA) to increase in the serum and liver of NASH patients. High levels of CBA in the liver are hypothesized to activate sphingosine-1-phosphate receptor 2 (S1PR2), activating pro-inflammatory and fibrosis pathways enhancing NASH progression. Because inflammation appears to be a major physiological driving force in NAFLD/NASH, new drugs and treatment protocols may require the use of anti-inflammatory compounds, such as berberine, in combination with bile acid receptor agonists or antagonists. Emerging new molecular technologies may provide guidance in unraveling the complex physiological pathways driving fatty liver disease and better approaches to prevention and treatment. © 2021 American Physiological Society. Compr Physiol 11:1-12, 2021.

The Effect of Dietary Intake and Nutritional Status on Anthropometric Development and Systemic Inflammation: An Observational Study

(1) Background: Daily caloric intake should aim to reduce the risk of obesity or poor anthropometric development. Our study objective was to analyze the association between food consumption, inflammatory status and anthropometric development; (2) Methods: We performed a prospective observational analytical research during September 2020 and April 2021 on a group of 160 healthy subjects, aged between 6 and 12 years old, by analyzing food ingestion, the basal metabolic rate, anthropometric development and the inflammatory status; (3) Results: IL-6 was significantly correlated to the sum of skinfolds, along with both serum proteins and triglycerides. The skin folds were significantly correlated with the caloric intake and with total fat intake, next to saturated and trans fats. Unlike the skin folds, the body weight was significantly correlated with the caloric intake along with some vitamins, such as Vitamin A and Vitamin B12. Inactive mass increased with excessive folic acid, Vitamin E, Vitamin K and saturated fat intake; (4) Conclusions: The inflammatory status was influenced by the ingestion of micronutrients, total serum lipids and proteins. The anthropometric development was associated with the ingestion of carbohydrates, energy balance and energy intake. We can conclude that daily menu and nutrition imbalances can influence both the risk of obesity and the inflammatory status.

Research Trends in the Efficacy of Stem Cell Therapy for Hepatic Diseases Based on MicroRNA Profiling

Liver diseases, despite the organ’s high regenerative capacity, are caused by several environmental factors and persistent injuries. Their optimal treatment is a liver transplantation. However, this option is limited by donor shortages and immune response issues. Therefore, many researchers have been interested in identifying the therapeutic potential in treating irreversible liver damage based on stem cells and developing suitable therapeutic agents. Mesenchymal stem cells (MSCs), which are representative multipotent stem cells, are known to be highly potential stem cell therapy compared to other stem cells in the clinical trial worldwide. MSCs have therapeutic potentials for several hepatic diseases such as anti-fibrosis, proliferation of hepatocytes injured, anti-inflammation, autophagic mechanism, and inactivation of hepatic stellate cells. There are much data regarding clinical treatments, however, the data for examining the efficacy of stem cell treatment and the correlation between the stem cell engraftment and the efficacy in liver diseases is limited due to the lack of monitoring system for treatment effectiveness. Therefore, this paper introduces the characteristics of microRNAs (miRNAs) and liver disease-specific miRNA profiles, and the possibility of a biomarker that miRNA can monitor stem cell treatment efficacy by comparing miRNAs changed in liver diseases following stem cell treatment. Additionally, we also discuss the miRNA profiling in liver diseases when treated with stem cell therapy and suggest the candidate miRNAs that can be used as a biomarker that can monitor treatment efficacy in liver diseases based on MSCs therapy.