Astaxanthin Alleviates Nonalcoholic Fatty Liver Disease by Regulating the Intestinal Flora and Targeting the AMPK/Nrf2 Signal Axis

Taraxasterol protects against acetaminophen-induced hepatotoxicity by reducing liver inflammatory response and ameliorating oxidative stress in mice

Acute liver failure is mainly caused by the overdose of acetaminophen (APAP) globally. The traditional Chinese medicinal (TCM) herb, Taraxacum, contains Taraxasterol (TAX) as one of the active components. It is a pentacyclic-triterpene compound isolated from this herb. Present work aimed to investigate the in vitro and in vivo protection effect of TAX in APAP-induced acute liver injury, and determine the potential regulatory mechamisms. The liver injury caused by APAP is attenuated by TAX, as shown by the alleviated pathological changes of mice liver and the reduced serological indexes. TAX evidently controlled the oxidative stress and liver inflammation in mice liver. In vitro studies found that TAX reversed the decrease in LO2 cell viability induced by APAP, and protected LO2 cells from APAP-induced injury. In addition, TAX reduced the secretion of inflammatory factors in RAW264.7 macrophages as induced via APAP. Besides, TAX inhibited oxidative stress in LO2 cells induced by APAP in vitro. Noteworthy, TAX enhanced protein and mRNA expressions of Nrf2 in vivo, and knockdown of Nrf2 by using adeno-associated virus (AAV)-Nrf2-KO attenuated inhibitory impact of TAX in acute liver injury induced by APAP. Also, AAV-NRF2-KO weakened the inhibitory impact of TAX against APAP-triggered liver inflammation and oxidative stress of mice liver. Moreover, TAX activated the Nrf2 signaling in APAP-induced LO2 cells, as shown by the increased nuclear Nrf2 expression together with downstream HO-1 expression in vitro. Inhibition of Nrf2 by using ML-385, anNrf2inhibitor, weakened the inhibitory effect of TAX against APAP-induced oxidative stress and cell injury in LO2 cells. Moreover, inhibition of Nrf2 attenuated anti-inflammatory effect of TAX for APAP-induced RAW264.7 cells. Collectively, TAX could protect against APAP-triggered hepatotoxicitythrough suppression of liver oxidative stress and inflammatory response in mice.

Bioprotective Role of Phytocompounds Against the Pathogenesis of Non-alcoholic Fatty Liver Disease to Non-alcoholic Steatohepatitis: Unravelling Underlying Molecular Mechanisms

Non-alcoholic fatty liver disease (NAFLD), with a global prevalence of 25%, continues to escalate, creating noteworthy concerns towards the global health burden. NAFLD causes triglycerides and free fatty acids to build up in the liver. The excessive fat build-up causes inflammation and damages the healthy hepatocytes, leading to non-alcoholic steatohepatitis (NASH). Dietary habits, obesity, insulin resistance, type 2 diabetes, and dyslipidemia influence NAFLD progression. The disease burden is complicated due to the paucity of therapeutic interventions. Obeticholic acid is the only approved therapeutic agent for NAFLD. With more scientific enterprise being directed towards the understanding of the underlying mechanisms of NAFLD, novel targets like lipid synthase, farnesoid X receptor signalling, peroxisome proliferator-activated receptors associated with inflammatory signalling, and hepatocellular injury have played a crucial role in the progression of NAFLD to NASH. Phytocompounds have shown promising results in modulating hepatic lipid metabolism and de novo lipogenesis, suggesting their possible role in managing NAFLD. This review discusses the ameliorative role of different classes of phytochemicals with molecular mechanisms in different cell lines and established animal models. These compounds may lead to the development of novel therapeutic strategies for NAFLD progression to NASH. This review also deliberates on phytomolecules undergoing clinical trials for effective management of NAFLD.

Exploring the Regulatory Effect of Tegillarca granosa Polysaccharide on High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease in Mice Based on Intestinal Flora

To explore the potential mechanism of action of Tegillarca granosa polysaccharide (TGP) in treating nonalcoholic fatty liver disease (NAFLD), the study conducts in vivo experiments using male C57BL/6 mice fed a high-fat diet while administering TGP for 16 weeks. The study measures body weight, liver weight, serum biochemical markers, pathological histology, liver lipid accumulation, oxidative stress and inflammation-related factors, lipid synthesis and metabolism-related gene and protein expression, and the composition and abundance of intestinal flora. Additionally, short-chain fatty acid (SCFAs) content and the correlation between intestinal flora and environmental factors are measured. The results show that TGP effectively reduces excessive hepatic lipid accumulation, dyslipidemia, abnormal liver function, and steatosis in the mice with NAFLD. Moreover, TGP effectively regulates intestinal flora disorder, increases the diversity of intestinal flora, and affects the relative abundance of specific bacteria while also increasing the content of SCFAs. These findings provide a basis for exploring the regulatory effect of T. granosa polysaccharide on NAFLD based on intestinal flora and highlight its potential as a natural liver nutraceutical.

Astaxanthin alleviates chronic prostatitis/chronic pelvic pain syndrome by increasing colonization of Akkermansia muciniphila in the intestine

BACKGROUND

Astaxanthin (AST) is a natural compound with anti-inflammatory/immunomodulatory properties that has been found to have probiotic properties. However, the role and mechanism of AST in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) are still not fully understood.

PURPOSE

The aim of this study was to evaluate the effect of AST on CP/CPPS and elucidate the mediating role of the gut microbiota.

MATERIALS AND METHODS

An experimental autoimmune prostatitis (EAP) mouse model was utilized to test the potential role of AST on CP/CPPS. Antibiotic cocktail (ABX) treatment and fecal microbiota transplantation (FMT) were used to elucidate the gut microbiota-mediated effects on AST. In addition, 16S rRNA gene sequencing and qRT-PCR analyses were used to analyze changes in the gut microbiota of EAP mice and CP/CPPS patients. Finally, the mechanism by which AST exerts a protective effect on CP/CPPS was explored by untargeted metabolomics and gut barrier function assays.

RESULTS

Oral administration of AST reduced prostate inflammation scores, alleviated tactile sensitization of the pelvic region in EAP mice, reduced CD4+ T cell and CD68+ macrophage infiltration in the prostatic interstitium, and inhibited the up-regulation of systemic and localized pain/pro-inflammatory mediators in the prostate. After ABX, the protective effect of AST against CP/CPPS was attenuated, whereas colonization with fecal bacteria from AST-treated EAP mice alleviated CP/CPPS. 16S rRNA gene sequencing and qRT-PCR analyses showed that Akkermansia muciniphila in the feces of EAP mice and CP/CPPS patients showed a trend toward a decrease, which was associated with poor progression of CP/CPPS. In contrast, oral administration of AST increased the relative abundance of A. muciniphila, and oral supplementation with A. muciniphila also alleviated inflammation and pain in EAP mice. Finally, we demonstrated that both AST and A. muciniphila interventions increased serum levels of SCFAs acetate, up-regulated expression of colonic tight junction markers, and decreased serum lipopolysaccharide levels in EAP mice.

CONCLUSION

Our results showed that AST improved CP/CPPS by up-regulating A. muciniphila, which provides new potentially effective strategies and ideas for CP/CPPS management.

Mechanism of Action and Related Natural Regulators of Nrf2 in Nonalcoholic Fatty Liver Disease

With the acceleration of people's pace of life, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world, which greatly threatens people's health and safety. Therefore, there is still an urgent need for higher-quality research and treatment in this area. Nuclear factor Red-2-related factor 2 (Nrf2), as a key transcription factor in the regulation of oxidative stress, plays an important role in inducing the body's antioxidant response. Although there are no approved drugs targeting Nrf2 to treat NAFLD so far, it is still of great significance to target Nrf2 to alleviate NAFLD. In recent years, studies have reported that many natural products treat NAFLD by acting on Nrf2 or Nrf2 pathways. This article reviews the role of Nrf2 in the pathogenesis of NAFLD and summarizes the currently reported natural products targeting Nrf2 or Nrf2 pathway for the treatment of NAFLD, which provides new ideas for the development of new NAFLD-related drugs.

Astaxanthin Protects against Alcoholic Liver Injury via Regulating Mitochondrial Redox Balance and Calcium Homeostasis

Increasing evidence points to the critical role of calcium overload triggered by mitochondrial dysfunction in the development of alcoholic liver disease (ALD). As an important organelle for aerobic respiration with a double-layered membrane, mitochondria are pivotal targets of alcohol metabolism-mediated lipid peroxidation, wherein mitochondria-specific phospholipid cardiolipin oxidation to 4-hydroxynonenal (4-HNE) ultimately leads to mitochondrial integrity and function impairment. Therefore, it is absolutely essential to identify effective nutritional intervention targeting mitochondrial redox function for an alternative therapy of ALD, in order to compensate for the difficulty in achieving alcohol withdrawal due to addiction. In this study, we confirmed the significant advantages of astaxanthin (AX) against alcohol toxicity among various carotenoids via cell experiments and identified the potential in mitochondrion morphogenesis and calcium signaling pathway by bioinformatics analysis. The ALD model of Sprague-Dawley (SD) rats was also generated to investigate the effectiveness of AX on alcohol-induced liver injury, and the underlying mechanisms were further explored. AX intervention attenuated alcohol-induced oxidative stress and lipid peroxidation as well as mitochondrial dysfunction characterized by degenerative morphology changes and collapsed membrane potential. Also, AX reduced the production of 4-HNE by activating the Nrf2-ARE signaling pathway, which is closely associated with the redox balance of mitochondria. In addition, relieved mitochondrial Ca2+ accumulation caused by AX was observed both in vivo and in vitro. Furthermore, we revealed the structure-activity relationship of AX and mitochondrial membrane channel proteins MCU and VDAC1, implying potential acting targets. Altogether, our data indicated a new mechanism of AX intervention which protects against alcohol-induced liver injury through restoring redox balance and Ca2+ homeostasis in mitochondria, as well as provided novel insights into the development of AX as a therapeutic option for the management of ALD.

A Narrative Review: The Effect and Importance of Carotenoids on Aging and Aging-Related Diseases

Aging is generally defined as a time-dependent functional decline that affects most living organisms. The positive increase in life expectancy has brought along aging-related diseases. Oxidative stress caused by the imbalance between pro-oxidants and antioxidants can be given as one of the causes of aging. At the same time, the increase in oxidative stress and reactive oxygen species (ROS) is main reason for the increase in aging-related diseases such as cardiovascular, neurodegenerative, liver, skin, and eye diseases and diabetes. Carotenoids, a natural compound, can be used to change the course of aging and aging-related diseases, thanks to their highly effective oxygen-quenching and ROS-scavenging properties. Therefore, in this narrative review, conducted using the PubMed, ScienceDirect, and Google Scholar databases and complying with the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines, the effects of carotenoids on aging and aging-related diseases were analyzed. Carotenoids are fat-soluble, highly unsaturated pigments that occur naturally in plants, fungi, algae, and photosynthetic bacteria. A large number of works have been conducted on carotenoids in relation to aging and aging-related diseases. Animal and human studies have found that carotenoids can significantly reduce obesity and fatty liver, lower blood sugar, and improve liver fibrosis in cirrhosis, as well as reduce the risk of cardiovascular disease and erythema formation, while also lowering glycated hemoglobin and fasting plasma glucose levels. Carotenoid supplementation may be effective in preventing and delaying aging and aging-related diseases, preventing and treating eye fatigue and dry eye disease, and improving macular function. These pigments can be used to stop, delay, or treat aging-related diseases due to their powerful antioxidant, restorative, anti-proliferative, anti-inflammatory, and anti-aging properties. As an increasingly aging population emerges globally, this review could provide an important prospective contribution to public health.

Plantamajoside modulates immune dysregulation and hepatic lipid metabolism in rats with nonalcoholic fatty liver disease via AMPK/Nrf2 elevation

Nonalcoholic fatty liver disease (NAFLD) is a hepatic metabolic syndrome with a rapidly increasing prevalence globally. Plantamajoside (PMS), a phenylethanoid glycoside component extracted from Plantago asiatica, has various biological properties. However, its effect on NAFLD remains unknown. The study aimed to explore the effect and mechanism of PMS on NAFLD in the high-fat diet (HFD)-feeding rats. PMS induced a decrease in body and liver weight, and the amelioration in the blood lipid parameters and pathological symptoms in HFD-feeding rats. The increase in the serum concentrations and the relative protein expressions of proinflammatory factors was decreased by the PMS treatment in HFD-induced NAFLD rats. Additionally, PMS reduced the excessive lipid vacuoles, and modified the relative expressions of proteins involved in the fatty acid synthesis and uptake in HFD-feeding rats. Mechanically, the downregulation of AMPK/Nrf2 pathway in HFD-feeding rats was restored by the PMS treatment. Inhibition of AMPK pathway reversed the PMS-induced the increase in the level of inflammatory factors, pathological symptoms, excessive lipid vacuoles, and the relative expression of proteins involved in the fatty acid synthesis and uptake. Collectively, PMS ameliorated immune dysregulation and abnormal hepatic lipid metabolism by activating AMPK/Nrf2 pathway in rats with NAFLD.

Tartary buckwheat flavonoids alleviates high-fat diet induced kidney fibrosis in mice by inhibiting MAPK and TGF-β1/Smad signaling pathway

Tartary buckwheat flavonoids (TBF) are active components extracted from Tartary buckwheat, which have abundant biological effects. According to this study, we investigated the effect of TBF on high-fat diet (HFD)-induced kidney fibrosis and its related mechanisms. In vivo, we established an HFD-induced kidney fibrosis model in mice and administered TBF. The results showed that TBF was able to alleviate kidney injury and inflammatory response. Subsequently, the mRNA levels between the HFD group and the TBF + HFD group were detected using RNA-seq assay. According to the gene set enrichment analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) results, the differential genes were enriched in lipid metabolism and mitogen-activated protein kinases(MAPK) signaling pathways. We examined the protein expression of lipid metabolism-related pathways and the level of lipid metabolism. The results showed that TBF significantly activated the adenosine monophosphate activated protein kinase/acetyl-CoA carboxylase (AMPK/ACC) pathway and effectively reduced kidney total cholesterol (TC), triglyceride (TG) and low-density lipoproteinc cholesterol (LDL-C) levels and increased high-density lipoprotein cholesterol (HDL-C) levels in mice. TBF also inhibited transforming growth factor-β1/Smad (TGF-β1/Smad) and MAPK signaling pathways, thus slowing down the kidney fibrosis process. In vitro, using palmitic acid (PA) to stimulate TCMK-1 cells, the in vivo results similarly demonstrated that TBF could alleviate kidney fibrosis in HFD mice by inhibiting TGF1/Smad signaling pathway and MAPK signaling pathway.

Natural Foods for the Treatment of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. The etiology of NAFLD is highly heterogeneous, which occurs and develops under the joint action of metabolism, inflammation, genetics, environment, and gut microbiota. At present, the principal therapeutic modalities targeting NAFLD are lifestyle interventions such as weight loss through diet and exercise. At present, there is no established therapy for the treatment of NAFLD, and many therapies are associated with a variety of side effects. A great number of in vitro and in vivo experiments have indicated that there are many natural foods that have therapeutic potential for NAFLD. This review summarizes the natural foods and their mechanisms that were found in recent years, furthermore, provides further information relevant to the treatment of NAFLD.

Structural Insights into Amelioration Effects of Quercetin and Its Glycoside Derivatives on NAFLD in Mice by Modulating the Gut Microbiota and Host Metabolism

The sugar moieties of natural flavonoids determine their absorption, bioavailability, and bioactivity in humans. To explore structure-dependent bioactivities of quercetin, isoquercetin, and rutin, which have the same basic skeleton linking different sugar moieties, we systemically investigated the ameliorative effects of dietary these flavonoids on high-fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) of mice. Our results revealed that isoquercetin exhibits the strongest capability in improving NAFLD phenotypes of mice, including body and liver weight gain, glucose intolerance, and systemic inflammation in comparison with quercetin and rutin. At the molecular level, dietary isoquercetin markedly ameliorated liver dysfunction and host metabolic disorders in mice with NAFLD. At the microbial level, the three flavonoids compounds, especially isoquercetin, can effectively regulate the gut microbiota composition, such as genera Akkermansia, Bifidobacterium, and Lactobacillus, which were significantly disrupted in NAFLD mice. These comparative findings offer new insights into the structure-dependent activities of natural flavonoids for NAFLD treatment.