Propionate Ameliorates Alcohol-Induced Liver Injury in Mice via the Gut-Liver Axis: Focus on the Improvement of Intestinal Permeability

Mogroside V prevents ethanol-induced hangover and liver damage by reducing oxidative stress, steatosis and inflammation

Excessive alcohol consumption is a leading cause of alcohol-associated liver disease (ALD). Previous studies presented Mogroside V (MV) have protective effects on against nonalcoholic fatty liver disease. however, the effects of MV on ethanol-induced hangover and liver damage remains to be elucidated. Herein, we investigated the potential effects of MV in relieving hangover and mitigating liver injury induced by ethanol. MV significantly reduced blood ethanol, liver histological alterations and serum ALT, AST、TG levels in ethanol-treated mice. Moreover, MV accelerates alcohol metabolism by inhibiting the upregulation of CYP2E1 induced by ethanol, while enhancing the activity of ADH and ALDH, as well as upregulating the expression of ADH1 and ALDH2. MV mitigates oxidative stress by decreased hepatic malondialdehyde (MDA) levels, restored glutathione (GSH)、superoxide dismutase (SOD) and catalase (CAT) content in ethanol-induced mice. Mechanistically, MV activated the p-AMPK/SREBP-1/FASN pathway to decreased hepatic lipid accumulation and alleviated steatosis. Additionally, MV promoted nuclear translocation of Nrf-2 to attenuates oxidative stress and suppressed TLR4/MyD88/NF-κB signaling pathway to reduce Inflammatory responses triggered by ethanol in mice. In summary, this study highlights mogroside V's hangover relieving effect and its protective effects against ethanol-related liver damage through its lipid metabolism regulation, antioxidative action and anti-inflammatory properties. These results suggest that mogroside V could be developed as a potential therapeutic agent against ethanol-induced liver damage.

Microbiota in Alcohol-Associated Organ Damage

Alcohol-associated organ damage is a major cause of morbidity and mortality worldwide, with the liver being the primarily affected organ. Emerging evidence highlights the gut microbiota as a key driver in alcohol-associated liver disease. Changes in the microbiota composition, microbial translocation, and a dysregulated immune response culminate in inflammation and tissue injury. Persistent liver injury eventually promotes disease progression from steatohepatitis to fibrosis and cirrhosis. In this review, we provide an overview of microbiota alterations observed in patients with chronic alcohol consumption and explore the mechanisms by which microbiota contributes to alcohol-associated damage across various organ systems. Emphasis is placed on changes in the gut microbiota and its role in alcohol-associated liver disease, the disease condition with the most robust evidence linking microbiota-related changes to organ injury. Additionally, we highlight key areas where further research is needed to address unresolved questions. Finally, we discuss emerging therapeutic strategies targeting the microbiota to treat alcohol use disorders and prevent alcohol-associated liver diseases.

Links between short-chain fatty acids and osteoarthritis from pathology to clinic via gut-joint axis

Short-chain fatty acids (SCFAs), the primary metabolites produced by the microbial fermentation of dietary fibers in the gut, have a key role in protecting gut health. Increasing evidence indicates SCFAs can exert effects on distant tissues and organs beyond the gut via blood circulation. Osteoarthritis (OA) is a chronic inflammatory joint disease that severely diminishes the physical function and quality of life. However, effective clinical treatments for OA remain elusive. Recent studies have shown that SCFAs can exert beneficial effects on damaged joints in OA. SCFAs can mitigate OA progression by preserving intestinal barrier function and maintaining the integrity of cartilage and subchondral bone, suggesting that they have substantial potential to be the adjunctive treatment strategy for OA. This review described the SCFAs in the human body and their cellular signaling mechanism, and summarized the multiple effects of SCFAs (especially butyrate, propionate, and acetate) on the prevention and treatment of OA by regulating the gut-joint axis, providing novel insights into their promising clinical applications.

Acidic polysaccharide CP-2 from Dioscoreae Rhizoma ameliorated acute alcoholic liver injury through the gut-liver axis and AMPK/PPAR pathway

Dioscoreae Rhizoma polysaccharides exhibit gastrointestinal protective properties, yet their efficacy against acute alcoholic liver injury (AALI) remains unexplored. This study identifies a novel acidic heteropolysaccharide (CP-2, Mw = 8.4 × 103 kDa) with galactose/galacturonic acid dominance and delineates its multimodal hepatoprotective mechanisms. In AALI mice, CP-2 attenuated liver injury by enhancing ADH and ALDH activities while restoring redox balance via SOD/CAT activation and MDA reduction, and suppressed inflammation by inhibiting IL-1β, IL-6, and TNF-α levels. Gut-liver axis modulation was achieved through intestinal barrier reinforcement (ZO-1, Occludin, Claudin-1) and microbiota rebalancing. CP-2 could reduce gram-negative bacteria ([Ruminococcus]_ torques_ group and Escherichia- Shigella) and Proteobacteria abundance while enriching Bacteroides and Akkermansia abundance, which collectively suppressed serum LPS level. In addition, CP-2 could activate the AMPK/PPAR signaling pathway to reduce the production of fatty acids and promote their degradation in AALI. CP-2 can improve AALI by adjusting the composition of gut microbiota, repairing intestinal barrier function, decreasing systemic inflammation and oxidative reactions, and regulating the AMPK/PPAR pathway. Our findings unveil CP-2 as a prebiotic candidate for AALI intervention and may advance functional food development for alcohol-related hepatopathies.

Green jackfruit flour ameliorates MASH and development of HCC via the AMPK and MAPK signaling pathways in experimental model systems

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a serious public health concern. Given the paucity of approved therapeutic strategies for this lifestyle disorder, dietary interventions may prove effective. We evaluated the mechanisms of how green jackfruit flour (JF) ameliorates metabolic-dysfunction-associated steatohepatitis (MASH) and halts the progression to hepatocellular carcinoma (HCC). The study used murine models of MASH and MASH-HCC that closely mimic human MASLD. C57Bl/6 male mice were fed with chow or western diet with normal or sugar water for 12 weeks, then randomized to receive either 5 kcal% green jackfruit flour (JF) or an equal volume of placebo flour (PB). JF significantly reduced body weight, liver injury, and insulin resistance, and alleviated obesity, steatosis, inflammation, fibrosis, and tumor development in WDSW or WDSW/CCl4 mice compared to placebo. Furthermore, JF activated AMPK (AMP-activated protein kinase) and inhibited MAPK (mitogen-activated protein kinase) signaling pathways in MASH and MASH-HCC models, respectively. Sodium propionate treatment, the primary short-chain fatty acid entering the liver from JF's soluble fiber microbial fermentation, further supported these mechanistic insights. Hence, our findings present strong evidence of JF's therapeutic potential in attenuating MASH and MASH-HCC, warranting further investigation of JF's efficacy as a dietary intervention in clinical trials.

Gut microbiota-mediated gut-liver axis: a breakthrough point for understanding and treating liver cancer

The trillions of commensal microorganisms living in the gut lumen profoundly influence the physiology and pathophysiology of the liver through a unique gut-liver axis. Disruptions in the gut microbial communities, arising from environmental and genetic factors, can lead to altered microbial metabolism, impaired intestinal barrier and translocation of microbial components to the liver. These alterations collaboratively contribute to the pathogenesis of liver disease, and their continuous impact throughout the disease course plays a critical role in hepatocarcinogenesis. Persistent inflammatory responses, metabolic rearrangements and suppressed immunosurveillance induced by microbial products underlie the pro-carcinogenic mechanisms of gut microbiota. Meanwhile, intrahepatic microbiota derived from the gut also emerges as a novel player in the development and progression of liver cancer. In this review, we first discuss the causes of gut dysbiosis in liver disease, and then specify the pivotal role of gut microbiota in the malignant progression from chronic liver diseases to hepatobiliary cancers. We also delve into the cellular and molecular interactions between microbes and liver cancer microenvironment, aiming to decipher the underlying mechanism for the malignant transition processes. At last, we summarize the current progress in the clinical implications of gut microbiota for liver cancer, shedding light on microbiota-based strategies for liver cancer prevention, diagnosis and therapy.

Lactobacillus extracellular vesicles alleviate alcohol-induced liver injury in mice by regulating gut microbiota and activating the Nrf-2 signaling pathway

Lactobacillus derived extracellular vesicles (LAB-EVs) are nanosized particles secreted from Lactobacillus during fermentation, and therefore exist universally in fermented foods such as yogurt, pickles, and fermented beverages. In this study, three LAB-EVs were prepared using a simple scalable method, and then their structures, compositions, and biosafety properties were characterized. The protective properties and potential mechanisms of action of the LAB-EVs against alcoholic liver disease were studied. All three LAB-EVs alleviated alcohol-induced liver injury. It was shown by reduction of liver index, histological damage, liver function impairment, inflammation, and liver oxidative status. The results showed that three LAB-EVs positively promoted the diversity of intestinal flora in mice. Additionally, the relative hepatic protein level of Nrf-2, HO-1, and CYP2E1 was also regulated by LAB-EVs. In summary, these facts suggest that the three LAB-EVs can alleviate alcohol-induced liver damage, by positively modulating the intestinal flora and activation of the Nrf-2 signaling pathway. These results may facilitate the understanding of the composition and function of Lactobacillus fermented food and also the development of Lactobacillus fermented functional food.

Probiotic Limosilactobacillus reuteri DSM 17938 Alleviates Acute Liver Injury by Activating the AMPK Signaling via Gut Microbiota-Derived Propionate

Limosilactobacillus reuteri DSM 17938 (L. reuteri DSM 17938) was one of the most widely used probiotics in humans for gastrointestinal disorders, but few studies have investigated its role in drug-induced liver injury (DILI). Here, we evaluated the efficacy of L. reuteri DSM 17938 using a mouse model of DILI induced by triptolide. Pregavage of L. reuteri DSM 17938 for 1 week remarkably lowered hepatic inflammatory cytokines level and oxidative stress, with diminished serum alanine transaminase and aspartate aminotransferase levels. Metabolomics and RT-qPCR analysis confirmed its ability in ameliorating TP-disrupted hepatic fatty acid β oxidation. Genome annotation of L. reuteri showed its ability to modulate energy metabolism. Targeted metabolomics demonstrated that L. reuteri DSM 17938 modified the short fatty acid profiles in cecum, especially enhancing propionate levels. Further experiments found that L. reuteri DSM 17938 can activate AMPK signaling by upregulating gut microbiota-derived propionate level, thus restoring impaired mitochondrial biogenesis and energy supply processes to recover energy homeostasis, which leads to diminished ROS production and oxidative stress injury in hepatocytes. Besides, AMPK inhibitor dorsomorphin abolished all the effects on propionate protecting mitochondria and energy metabolism. This study established probiotic therapy of L. reuteri DSM 17938 as a preventive intervention for DILI in clinical. We also revealed that L. reuteri DSM 17938 can activate AMPK signaling by propionate, facilitating a deeper understanding of the action mechanism of L. reuteri DSM 17938 against acute liver injury and contributing to the development of its postbiotics and wider applications.

Apple polyphenols prevent patulin-induced intestinal damage by modulating the gut microbiota and metabolism of the gut-liver axis

Patulin (PAT), a foodborne toxin, causes severe intestinal damage. To mitigate this health threat, mice were pretreated with apple polyphenols (AP) in their drinking water (0.01 % and 0.05 %) for eight weeks, followed by exposure to PAT during the last two weeks. Subsequently, histopathological and biochemical evaluations of intestinal tissues were conducted, alongside assessments of alterations in gut microbiota, colonic content metabolome, and hepatic metabolome. Consequently, AP alleviated PAT-induced villus and crypt injury, mucus depletion, GSH level decline, GSH-Px and SOD activity reduction, and MPO activity elevation. Notably, AP counteracted PAT-mediated microbiota disruptions and promoted the abundance of beneficial bacteria (Dubosiella, Akkermansia, Lachnospiraceae, and Lactobacillus). Furthermore, AP counteracted PAT-induced metabolic disorders in the colonic contents and liver. Ultimately, AP prevented intestinal injury by regulating the gut microbiota and amino acid, purine, butanoate, and glycerophospholipid metabolism in the gut-liver axis. These results underscore the potential of AP to prevent foodborne toxin-induced intestinal damage.

Green Radish Polysaccharide Prevents Alcoholic Liver Injury by Interfering with Intestinal Bacteria and Short-Chain Fatty Acids in Mice

This study aimed to ascertain the potential benefits of green radish polysaccharide (GRP) in treating alcoholic liver disease (ALD) in mice and explore its mechanism of action. Using biochemical analysis, high-throughput sequencing of gut microbiota, and gas chromatography-mass spectrometry to measure short-chain fatty acids (SCFAs) in feces, we found that GRP intervention significantly improved lipid metabolism and hepatic function in mice subjected to excessive alcohol intake. The GRP intervention reduced malondialdehyde levels by 66% and increased total superoxide dismutase levels by 22%, thereby mitigating alcohol-induced oxidative stress. Furthermore, GRP intervention in mice with alcohol consumption resulted in a reduction in tumor necrosis factor, interleukin 6, and lipopolysaccharide levels by 12%, 9%, and 25%, respectively, effectively attenuating alcoholic liver inflammation. 16S rRNA amplicon sequencing demonstrated that excessive alcohol consumption markedly altered the gut microbiota composition in mice. The GRP treatment resulted in a significant reduction in the number of beneficial bacteria (Lactobacillus and Lachnospiraceae_NK4A136_group) and an increase in the proportion of harmful bacteria (Muribaculaceae and Verrucomicrobiota). The metabolomic analyses of the SCFAs demonstrated an increase in the contents of SCFAs, acetic acid, propionic acid, and butyric acid, following GRP supplementation. Furthermore, the metabolic levels of cholinergic synapses and glycolysis/gluconeogenesis were found to be modulated. In conclusion, these findings suggest that GRP may attenuate alcohol-induced oxidative damage in the liver by modulating the gut microbiota and hepatic metabolic pathways. This may position GRP as a potential functional component for ALD prevention.

Minibioreactor arrays to model microbiome response to alcohol and tryptophan in the context of alcohol-associated liver disease

The intestinal microbiota (IM) plays a role in the severity of alcohol-associated liver disease. Modifying severe alcohol-associated hepatitis (AH) dysbiosis improves liver injury through tryptophan (Trp) metabolites and the aryl hydrocarbon receptor (AhR). However, Trp's effect on the IM in alcohol use disorder (AUD) patients remains unclear. Here, we used an in vitro microbiota modeling system named Minibioreactor arrays (MBRAs). Feces from AUD patients with or without AH were treated with low, normal, or high Trp concentrations, with subsequent treatment with alcohol. Microbiota composition and AhR activity were studied. We showed that microbial communities from donors were maintained in MBRAs. High and low Trp increased the abundance of pathogen Escherichia Shigella. In the absence of alcohol, Trp changed more bacteria in AUD IM compared to AH IM. Normal Trp increased the AhR activity. Overall, maintaining normal Trp levels may prevent dysbiosis in AUD or AH, pending in vivo confirmation.

Lactobacillus helveticus attenuates alcoholic liver injury via regulation of gut microecology in mice

Previous reports have demonstrated that alcohol consumption significantly reduces the abundance of Lactobacillus in the gut. In this study, we selected five species of the genus Lactobacillus, commonly found in fermented foods, and acknowledged them as safe, edible, and effective in preventing or treating certain diseases, to evaluate their effects on alcoholic liver disease (ALD). By comparing the liver damage indices in each group, we found that the type strain of Lactobacillus helveticus (LH, ATCC 15009) had the most marked alleviating effect on ALD-induced liver injury. Furthermore, experiments combining microbiomics and metabolomics were conducted to explore the mechanisms underlying the hepatoprotective effects of LH. Finally, we discovered that LH mitigated ethanol-induced liver steatosis and inflammation in ALD mice by altering the structure and function of the gut microbiome, increasing intestinal levels of short-chain fatty acids (SCFAs), and enhancing gut barrier integrity. These findings suggest a potential strategy for the clinical management of patients with ALD.

Immune response for acute Aeromonas hydrophila infection in two distinct color morphs of northern snakehead, Channa argus

To compare and analyze the differences in immunological response between the two color morphs of Channa argus, a fish cohort was divided into four groups: black C argus + PBS (B-PBS), black C argus + Aeromonas hydrophila (B-Ah), white C. argus + PBS (W-PBS), and white C. argus + A hydrophila (W-Ah). The B-PBS and W-PBS groups received 100 μL PBS, while the B-Ah and W-Ah groups received 3.6 × 105 CFU/mL A. hydrophila in the same volume. The death rate in each group was noted, changes in plasma biochemical indicators and the expression of liver immune-related genes were examined, and transcriptome techniques were used to compare the differences between the two colors of C. argus following stress. No mortality occurred in the B-PBS and W-PBS groups. Mortality in the W-Ah and B-Ah groups showed an upward and then downward trend after A. hydrophila injection. The highest mortality occurred within 24 h and was higher in the W-Ah group than in the B-Ah group. MDA levels in the B-Ah and W-Ah groups increased and then decreased, while SOD and T-AOC showed the reverse tendency. The W-Ah and W-PBS groups differed significantly in MDA at 3, 12, and 24 h, SOD from 6 to 96 h, and T-AOC between 6 and 48 h. Plasma MDA and T-AOC levels at 12 h and SOD levels at 24 and 48 h differed significantly between the B-PBS and B-Ah groups. In both the W-Ah and B-Ah groups, the expression levels of IL-1β and IL-8 in the liver showed a temporal pattern with an initial increase followed by a decrease, reaching peak levels after 24 h, while IL-10 showed the reverse pattern. Transcriptome analysis of the liver revealed significant differences between the two C. argus colors. Differential genes in black C. argus were mainly enriched in steroid biosynthesis, glycolysis/gluconeogenesis, and glutathione and propanoate metabolism pathways 24 h after infection. In contrast, differential genes in white C. argus were mainly enriched in pathways such as oxidative phosphorylation, pancreatic secretion, and protein digestion and absorption 24 h after infection. After A. hydrophila infection, white C. argus had higher mortality, more severe oxidative stress and inflammatory responses, and lower antioxidant capacity than black C. argus.

A Butyrate-Yielding Dietary Supplement Prevents Acute Alcoholic Liver Injury by Modulating Nrf2-Mediated Hepatic Oxidative Stress and Gut Microbiota

Alcoholic liver disease (ALD) is a globally prevalent form of liver disease for which there is no effective treatment. Recent studies have found that a significant decrease in butyrate was closely associated with ALD development. Given the low compliance and delivery efficiency associated with oral-route butyrate administration, a highly effective butyrate-yielding dietary supplement, butyrylated high-amylose maize starch (HAMSB), is a good alternative approach. Here, we synthesized HAMSB, evaluated the effect of HAMSB on acute ALD in mice, compared its effect with that of oral administration of butyrate, and further studied the potential mechanism of action. The results showed HAMSB alleviated acute ALD in mice, as evidenced by the inhibition of hepatic-function impairment and the improvement in liver steatosis and lipid metabolism; in these respects, HAMSB supplementation was superior to oral sodium butyrate administration. These improvements can be attributed to the reduction of oxidative stress though the regulation of Nrf2-mediated antioxidant signaling in the liver and the improvement in the composition and function of microbiota in the intestine. In conclusion, HAMSB is a safe and effective dietary supplement for preventing acute ALD that could be useful as a disease-modifying functional food or candidate medicine.

Molecular mechanisms and therapeutic possibilities of short-chain fatty acids in posttraumatic stress disorder patients: a mini-review

This mini-review explores the role of short-chain fatty acids (SCFAs) in posttraumatic stress disorder (PTSD). Highlighting the microbiota-gut-brain axis, this study investigated the bidirectional communication between the gut microbiome and mental health. SCFAs, byproducts of gut microbial fermentation, have been examined for their potential impact on PTSD, with a focus on molecular mechanisms and therapeutic interventions. This review discusses changes in SCFA levels and bacterial profiles in individuals with PTSD, emphasizing the need for further research. Promising outcomes from clinical trials using probiotics and fermented formulations suggest potential avenues for PTSD management. Future directions involve establishing comprehensive human cohorts, integrating multiomics data, and employing advanced computational methods, with the goal of deepening our understanding of the role of SCFAs in PTSD and exploring microbiota-targeted interventions.

Digestive dynamics: Unveiling interplay between the gut microbiota and the liver in macronutrient metabolism and hepatic metabolic health

Although the liver is the largest metabolic organ in the body, it is not alone in functionality and is assisted by "an organ inside an organ," the gut microbiota. This review attempts to shed light on the partnership between the liver and the gut microbiota in the metabolism of macronutrients (i.e., proteins, carbohydrates, and lipids). All nutrients absorbed by the small intestines are delivered to the liver for further metabolism. Undigested food that enters the colon is metabolized further by the gut microbiota that produces secondary metabolites, which are absorbed into portal circulation and reach the liver. These microbiota-derived metabolites and co-metabolites include ammonia, hydrogen sulfide, short-chain fatty acids, secondary bile acids, and trimethylamine N-oxide. Further, the liver produces several compounds, such as bile acids that can alter the gut microbial composition, which can in turn influence liver health. This review focuses on the metabolism of these microbiota metabolites and their influence on host physiology. Furthermore, the review briefly delineates the effect of the portosystemic shunt on the gut microbiota-liver axis, and current understanding of the treatments to target the gut microbiota-liver axis.

Fecal microbiota transplantation in the treatment of hepatic encephalopathy: A perspective

Due to its complex pathogenesis, treatment of hepatic encephalopathy (HE) continues to be a therapeutic challenge. Of late, gut microbiome has garnered much attention for its role in the pathogenesis of various gastrointestinal and liver diseases and its potential therapeutic use. New evidence suggests that gut microbiota plays a significant role in cerebral homeostasis. Alteration in the gut microbiota has been documented in patients with HE in a number of clinical and experimental studies. Research on gut dysbiosis in patients with HE has opened newer therapeutic avenues in the form of probiotics, prebiotics and the latest fecal microbiota transplantation (FMT). Recent studies have shown that FMT is safe and could be effective in improving outcomes in advanced liver disease patients presenting with HE. However, questions over the appropriate dose, duration and route of administration for best treatment outcome remains unsettled.

Ameliorative effect of total ginsenosides from heat-treated fresh ginseng against cyclophosphamide-induced liver injury in mice

This study evaluated the effect of heat treatment on the conversion of ginsenoside and the ameliorative effect of heat-treated total ginsenoside (HG) from fresh ginseng on cyclophosphamide (CTX)-induced liver injury. LC-MS analysis revealed that the content of rare ginsenosides increased markedly after heat treatment. HG significantly attenuated CTX-induced hepatic histopathological injury in mice. Western blotting analysis showed that untreated total ginsenoside (UG) and HG regulated the Nrf2/HO-1 and TLR4/MAPK pathways. Importantly, these results may be relevant to the modulation of the intestinal flora. UG and HG significantly increased the short-chain fatty acids (SCFAs)-producing bacteria Lactobacillus and reduced the LPS-producing bacteria Bacteroides and Parabacteroides. These changes in intestinal flora affected the levels of TNF-α, LPS and SCFAs. In short, UG and HG alleviated CTX-induced liver injury by regulating the intestinal flora and the LPS-TLR4-MAPK pathway, and HG was more effective. HG has the potential to be a functional food that can alleviate chemical liver injury.

The gut-liver axis in fatty liver disease: role played by natural products

Fatty liver disease, a condition characterized by fatty degeneration of the liver, mainly classified as non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), has become a leading cause of cirrhosis, liver cancer and death. The gut-liver axis is the bidirectional relationship between the gut and its microbiota and its liver. The liver can communicate with the gut through the bile ducts, while the portal vein transports the products of the gut flora to the liver. The intestinal flora and its metabolites directly and indirectly regulate hepatic gene expression, leading to an imbalance in the gut-liver axis and thus contributing to the development of liver disease. Utilizing natural products for the prevention and treatment of various metabolic diseases is a prevalent practice, and it is anticipated to represent the forthcoming trend in the development of drugs for combating NAFLD/ALD. This paper discusses the mechanism of the enterohepatic axis in fatty liver, summarizes the important role of plant metabolites in natural products in fatty liver treatment by regulating the enterohepatic axis, and provides a theoretical basis for the subsequent development of new drugs and clinical research.

Echinacea purpurea polysaccharide intervene in hepatocellular carcinoma via modulation of gut microbiota to inhibit TLR4/NF-κB pathway

Echinacea purpurea polysaccharide (EPP) exhibit various pharmacological activities, including immunomodulatory, anti-inflammatory, and anti-tumor effects. In this study, we investigated the potential mechanism of EPP intervention in hepatocellular carcinoma (HCC). The results demonstrated that EPP effectively mitigated liver injury caused by HCC, inhibited the proliferation of HCC, and induced apoptosis. Following EPP intervention, there was a significant increase in propionic acid and butyric acid-producing gut microbiota such as Coprococcus, Clostridium and Roseburia, leading to enhanced expression of intestinal tight junction proteins and the repair of the intestinal barrier. This controls lipopolysaccharide (LPS) leakage, which in turn inhibits the TLR4/NF-κB pathway and reduces the expression of inflammatory factors such as IL-6, as well as migration factors like MMP-2. Metabolomics revealed the downregulation of pyrimidine metabolism and nucleotide metabolism, along with the upregulation of butyrate metabolism in tumor cells. This study demonstrated that EPP effectively regulated LPS leakage by modulating gut microbes, and this modulation influenced the TLR4/NF-κB pathway, ultimately disrupting tumor cell survival induced by HCC in mice.

Daily Cashew and Brazil Nut Consumption Modifies Intestinal Health in Overweight Women on Energy-Restricted Intervention: A Randomized Controlled Trial (Brazilian Nuts Study)

BACKGROUND

Increased intestinal permeability and dysbiosis are related to obesity. Nuts can provide nutrients and bioactive compounds that modulate gut microbiota and inflammation, enhancing the beneficial effects of weight loss.

OBJECTIVES

To evaluate the effect of consuming cashew nuts (Anacardium occidentale L.) and Brazil nuts (Bertholletia excelsa H.B.K) on intestinal permeability and microbiota, fecal SCFAs and pH, inflammation, and weight loss in energy restriction condition.

METHODS

In this 8-week randomized controlled trial, 40 women with overweight or obesity were assigned to energy-restricted groups (-500 kcal/d): control group (free of nuts) or Brazilian nuts group (BN: 30 g of cashew nuts and 15 g of Brazil nuts per day). Permeability was analyzed by the lactulose/mannitol test and the microbiota by sequencing the 16S gene in the V3-V4 regions. Plasma concentrations of inflammatory cytokines (TNF, IL-6, IL-10, IL-8, IL-17A) and C-reactive protein were analyzed.

RESULTS

In total, 25 women completed the intervention. Both groups lost weight without statistical differences. Lactulose excretion increased only in the control group (P < 0.05). The BN consumption increased fecal propionic acid and potentially beneficial bacteria, such as Ruminococcus, Roseburia, strains NK4A214 and UCG-002 from the Ruminococcaceae family, but also Lachnospiraceae family, Bacteroides, and Lachnoclostridium, when compared to the control group. Changes in intestinal permeability were correlated to a greater reduction in body fat (kg), and IL-8, and increases in Ruminococcus abundance.

CONCLUSION

Our findings demonstrate a positive impact of BN consumption within an energy-restricted context, linked to the augmentation of potentially beneficial bacteria and pathways associated with body fat reduction. Besides, BN consumption mitigated increased intestinal permeability, although its capacity to diminish permeability or enhance weight loss proved limited. This trial was registered at the Brazilian Registry of Clinical Trials as ReBEC (ID: RBR-3ntxrm).

MUP1 mediates urolithin A alleviation of chronic alcohol-related liver disease via gut-microbiota-liver axis

Alcohol-related liver disease (ALD) is recognized as a global health crisis, contributing to approximately 20% of liver cancer-associated fatalities. Dysbiosis of the gut microbiome is associated with the development of ALD, with the gut microbial metabolite urolithin A (UA) exhibiting a potential for alleviating liver symptoms. However, the protective efficacy of UA against ALD and its underlying mechanism mediated by microbiota remain elusive. In this study, we provide evidence demonstrating that UA effectively ameliorates alcohol-induced metabolic disorders and hepatic endoplasmic reticulum (ER) stress through a specific gut-microbiota-liver axis mediated by major urinary protein 1 (MUP1). Moreover, UA exhibited the potential to restore alcohol-induced dysbiosis of the intestinal microbiota by enriching the abundance of Bacteroides sartorii (B. sartorii), Parabacteroides distasonis (P. distasonis), and Akkermansia muciniphila (A. muciniphila), along with their derived metabolite propionic acid. Partial attenuation of the hepatoprotective effects exerted by UA was observed upon depletion of gut microbiota using antibiotics. Subsequently, a fecal microbiota transplantation (FMT) experiment was conducted to evaluate the microbiota-dependent effects of UA in ALD. FMT derived from mice treated with UA exhibited comparable efficacy to direct UA treatment, as it effectively attenuated ER stress through modulation of MUP1. It was noteworthy that strong associations were observed among the hepatic MUP1, gut microbiome, and metabolome profiles affected by UA. Intriguingly, oral administration of UA-enriched B. sartorii, P. distasonis, and A. muciniphila can enhance propionic acid production to effectively suppress ER stress via MUP1, mimicking UA treatment. Collectively, these findings elucidate the causal mechanism that UA alleviated ALD through the gut-microbiota-liver axis. This unique mechanism sheds light on developing novel microbiome-targeted therapeutic strategies against ALD.

Roles of gut microbes in metabolic-associated fatty liver disease

Metabolic-associated fatty liver disease (MAFLD) is the most common chronic liver disease. Gut dysbiosis is considered a significant contributing factor in disease development. Increased intestinal permeability can be induced by gut dysbiosis, followed by the entry of lipopolysaccharide into circulation to reach peripheral tissue and result in chronic inflammation. We reviewed how microbial metabolites push host physiology toward MAFLD, including short-chain fatty acids (SCFAs), bile acids, and tryptophan metabolites. The effects of SCFAs are generally reported as anti-inflammatory and can improve intestinal barrier function and restore gut microbiota. Gut microbes can influence intestinal barrier function through SCFAs produced by fermentative bacteria, especially butyrate and propionate producers. This is achieved through the activation of free fatty acid sensing receptors. Bile is directly involved in lipid absorption. Gut microbes can alter bile acid composition by bile salt hydrolase-producing bacteria and bacterial hydroxysteroid dehydrogenase-producing bacteria. These bile acids can affect host physiology by activating farnesoid X receptor Takeda G protein-coupled receptor 5. Gut microbes can also induce MAFLD-associated symptoms by producing tryptophan metabolites kynurenine, serotonin, and indole-3-propionate. A summary of bacterial genera involved in SCFAs production, bile acid transformation, and tryptophan metabolism is provided. Many bacteria have demonstrated efficacy in alleviating MAFLD in animal models and are potential therapeutic candidates for MAFLD.

Intestinal Microbiotas and Alcoholic Hepatitis: Pathogenesis and Therapeutic Value

Alcoholic hepatitis (AH) is a rapidly progressing and severe stage of alcoholic liver disease, presenting a grim prognosis. Extensive research has elucidated several underlying mechanisms that contribute to the development of AH, including metabolic alterations, immune stimulation, and intestinal dysbiosis. These pathological changes intricately intertwine during the progression of AH. Notably, recent studies have increasingly highlighted the pivotal role of alterations in the intestinal microbiota in the pathogenesis of AH. Consequently, future investigations should place significant emphasis on exploring the dynamics of intestinal microbiota. In this comprehensive review, we consolidate the primary causes of AH while underscoring the influence of gut microbes. Furthermore, by examining AH treatment strategies, we delineate the potential therapeutic value of interventions targeting the gut microbiota. Given the existing limitations in AH treatment options, we anticipate that this review will contribute to forthcoming research endeavors aimed at advancing AH treatment modalities.

Ginsenoside Rk2, a dehydroprotopanaxadiol saponin, alleviates alcoholic liver disease via regulating NLRP3 and NLRP6 inflammasome signaling pathways in mice

Heavy alcohol consumption results in alcoholic liver disease (ALD) with inadequate therapeutic options. Here, we first report the potential beneficial effects of ginsenoside Rk2 (Rk2), a rare dehydroprotopanaxadiol saponin isolated from streamed ginseng, against alcoholic liver injury in mice. Chronic-plus-single-binge ethanol feeding caused severe liver injury, as manifested by significantly elevated serum aminotransferase levels, hepatic histological changes, increased lipid accumulation, oxidative stress, and inflammation in the liver. These deleterious effects were alleviated by the treatment with Rk2 (5 and 30 mg/kg). Acting as an nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inhibitor, Rk2 ameliorates alcohol-induced liver inflammation by inhibiting NLRP3 inflammasome signaling in the liver. Meanwhile, the treatment with Rk2 alleviated the alcohol-induced intestinal barrier dysfunction via enhancing NLRP6 inflammasome in the intestine. Our findings indicate that Rk2 is a promising agent for the prevention and treatment of ALD and other NLPR3-driven diseases.

Novel application potential of cinaciguat in the treatment of mixed hyperlipidemia through targeting PTL/NPC1L1 and alleviating intestinal microbiota dysbiosis and metabolic disorders

Mixed hyperlipidemia, characterized by high levels of triglycerides and cholesterol, is a key risk factor leading to atherosclerosis and other cardiovascular diseases. Existing clinical drugs usually only work on a single indicator, decreasing either triglyceride or cholesterol levels. Developing dual-acting agents that reduce both triglycerides and cholesterol remains a great challenge. Pancreatic triglyceride lipase (PTL) and Niemann-Pick C1-like 1 (NPC1L1) have been identified as crucial proteins in the transport of triglycerides and cholesterol. Here, cinaciguat, a known agent used in the treatment of acute decompensated heart failure, was identified as a potent dual inhibitor targeting PTL and NPC1L1. We presented in vitro evidence from surface plasmon resonance analysis that cinaciguat interacted with PTL and NPC1L1. Furthermore, cinaciguat exhibited potent PTL-inhibition activity. Fluorescence-labeled cholesterol uptake analysis and confocal imaging showed that cinaciguat effectively inhibited cholesterol uptake. In vivo evaluation showed that cinaciguat significantly reduced the plasma levels of triglycerides and cholesterol, and effectively alleviated high-fat diet-induced intestinal microbiota dysbiosis and metabolic disorders. These results collectively suggest that cinaciguat has the potential to be further developed for the therapy of mixed hyperlipidemia.

Effects of ethanol and sex on propionate metabolism evaluated via a faster 13C-propionate breath test in rats

BACKGROUND

Alcoholism is regarded as a risk factor for vitamin B₁₂ (VB₁₂) deficiency. Because VB₁₂ serves as a coenzyme of methylmalonyl-CoA mutase, a key enzyme in propionate metabolism, the ¹³C-propionate breath test (PBT) has been studied as a non-invasive diagnostic modality for VB₁₂ deficiency. However, the conventional PBT requires 2 h, which is inconvenient in clinical practice. We hypothesized that a faster PBT can be used to evaluate propionate metabolism and is more easily adaptable for clinical practice.

AIM

To evaluate a faster PBT for assessing the effects of long-term ethanol consumption on propionate metabolism in ethanol-fed rats (ERs).

METHODS

ERs were obtained by replacing standard drinking water (for control rats, CRs) with 16% ethanol solution in descendants of F344/DuCrj rats. Faster PBT was performed by administering ¹³C-propionate aqueous solution to male and female ERs and CRs by inserting a metal tubule from the mouth to the stomach; exhaled gas was collected in a bag to measure its ¹³CO₂/¹²CO₂ isotope ratio via infrared isotope spectrometry. Serum VB₁₂ and alanine transaminase (ALT) levels were measured via chemiluminescence immunoassay and the lactate dehydrogenase-ultraviolet method, respectively. We evaluated statistical differences in mean body weight, change in ¹³CO₂ (Δ¹³CO₂‰), peak Δ¹³CO₂‰, and serum VB₁₂ and ALT, between males and females and between ERs and CRs using the t-test and Mann-Whitney U test for normally and non-normally distributed variables, respectively.

RESULTS

Males weighed significantly more than females (P < 0.001); CRs weighed significantly more than ERs (P < 0.008). Δ¹³CO₂ reached a peak (C_max) at 20 min and 30 min in females and males, respectively, decreasing after 20-30 min without rebound in all groups. Males had significantly higher C_max and Δ¹³CO₂ at 15-45 min than females (P < 0.05; for all pairs). Propionate metabolism was enhanced in male ERs relative to male CRs, whereas metabolism did not differ markedly between ERs and CRs for females. Males had higher serum VB₁₂ levels than females, without prominent differences between the ER and CR groups. Male CRs had notably higher ALT levels than male ERs. Thus, chronic ethanol consumption may trigger fatty acid production via intestinal bacteria and changes in gut microbiome composition.

CONCLUSION

Faster PBT shows that 16% ethanol consumption promotes propionate metabolism without inducing liver injury. This PBT may be used clinically to evaluate gut flora status.

Integrating metabonomics and metagenomics sequencing to study the anti-liver fibrosis effects of palmatine in Corydalis saxicola Bunting

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis saxicola Bunting (CS), a traditional Chinese folk medicine, has been effectively used for treating liver disease in Zhuang nationality in South China. However, the main anti-liver fibrosis ingredients in CS are incompletely understood.

AIM OF THE STUDY

To elucidate the main anti-liver fibrosis ingredients in CS and its underlying mechanism.

MATERIAL AND METHODS

Firstly, spectrum-effect relationship (SER) strategy was applied to identify the major ingredients against liver fibrosis in CS. Subsequently, ¹H NMR metabonomics and metagenomics sequencing techniques were used to clarify the intervention of palmatine (PAL) on liver fibrosis. Furthermore, the expression of tight junction proteins and the levels of liver inflammation factors were examination, the effect of PAL on microbiota was verified by FMT.

RESULTS

The SER model revealed that PAL was the most important active ingredient in CS. ¹H NMR fecal metabonomics showed that PAL could reserve the abnormal levels of gut microbial-mediated metabolites of liver fibrosis, such as isoleucine, taurine, butyrate, propionate, lactate, glucose, which mainly involved in amino acid metabolism, intestinal flora metabolism and energy metabolism. Metagenomics sequencing found that PAL could callback the abundance of s__Lactobacillus_murinus, s__Lactobacillus_reuteri, s__Lactobacillus_johnsonii, s__Lactobacillus_acidophilus and s__Faecalibaculum_rodentium to varying degree. Furthermore, the intestinal barrier function and the levels of hepatic inflammation factors were significantly ameliorated by PAL. FMT demonstrated that the therapeutic efficiency of PAL was closely associated with gut microbiota.

CONCLUSION

The effects of CS on liver fibrosis were attributed in part to PAL by alleviating metabolic disorders and rebalancing gut microbiota. The SER strategy may be a useful method for the discovery of active constituents in natural plants.

Therapeutic strategies of small molecules in the microbiota-gut-brain axis for alcohol use disorder

The microbiota-gut-brain axis (MGBA) is important in maintaining the structure and function of the central nervous system (CNS) and is regulated by the CNS environment and signals from the peripheral tissues. However, the mechanism and function of the MGBA in alcohol use disorder (AUD) are still not completely understood. In this review, we investigate the underlying mechanisms involved in the onset of AUD and/or associated neuronal deficits and create a foundation for better treatment (and prevention) strategies. We summarize recent reports focusing on the alteration of the MGBA in AUD. Importantly, we highlight the properties of small-molecule short-chain fatty acids (SCFAs), neurotransmitters, hormones, and peptides in the MGBA and discusses their usage as therapeutic agents against AUD.

Gut Dysbiosis and Blood-Brain Barrier Alteration in Hepatic Encephalopathy: From Gut to Brain

A common neuropsychiatric complication of advanced liver disease, hepatic encephalopathy (HE), impacts the quality of life and length of hospital stays. There is new evidence that gut microbiota plays a significant role in brain development and cerebral homeostasis. Microbiota metabolites are providing a new avenue of therapeutic options for several neurological-related disorders. For instance, the gut microbiota composition and blood-brain barrier (BBB) integrity are altered in HE in a variety of clinical and experimental studies. Furthermore, probiotics, prebiotics, antibiotics, and fecal microbiota transplantation have been shown to positively affect BBB integrity in disease models that are potentially extendable to HE by targeting gut microbiota. However, the mechanisms that underlie microbiota dysbiosis and its effects on the BBB are still unclear in HE. To this end, the aim of this review was to summarize the clinical and experimental evidence of gut dysbiosis and BBB disruption in HE and a possible mechanism.

Sulforaphane Ameliorates Nonalcoholic Fatty Liver Disease Induced by High-Fat and High-Fructose Diet via LPS/TLR4 in the Gut-Liver Axis

The gut-liver axis has emerged as a key player in the progression of non-alcoholic fatty liver disease (NAFLD). Sulforaphane (SFN) is a bioactive compound found in cruciferous vegetables; however, it has not been reported whether SFN improves NAFLD via the gut-liver axis. C57BL/6 mice were fed a high-fat and high-fructose (HFHFr) diet, with or without SFN gavage at doses of 15 and 30 mg·kg^-1 body weight for 12 weeks. The results showed that SFN reduced weight gain, hepatic inflammation, and steatosis in HFHFr mice. SFN altered the composition of gut microbes. Moreover, SFN enhanced the intestinal tight junction protein ZO-1, reduced serum LPS, and inhibited LPS/TLR4 and ERS pathways to reduce intestinal inflammation. As a result, SFN protected the intestinal integrity and declined the gut-derived LPS translocations to the liver in HFHFr diet-induced mice. SFN decreased the liver LPS levels and inhibited the LPS/TLR4 pathway activations, thus inhibiting the pro-inflammatory cytokines. Notably, Spearman correlation analysis showed that the protective effect of SFN on intestinal barrier integrity and its anti-inflammatory effect on the liver was associated with improved intestinal dysbiosis. Above all, dietary intervention with SFN attenuates NAFLD through the gut-liver axis.

The harmful intestinal microbial community accumulates during DKD exacerbation and microbiome-metabolome combined validation in a mouse model

OBJECTIVE

Diabetic kidney disease (DKD) is one of the most prevalent complications of diabetes mellitus (DM) and is associated with gut microbial dysbiosis. We aim to build a diagnostic model to aid clinical practice and uncover a crucial harmful microbial community that contributes to DKD pathogenesis and exacerbation.

DESIGN

A total of 528 fecal samples from 180 DKD patients and 348 non-DKD populations (138 DM and 210 healthy volunteers) from the First Affiliated Hospital of Zhengzhou University were recruited and randomly divided into a discovery phase and a validation phase. The gut microbial composition was compared using 16S rRNA sequencing. Then, the 180 DKD patients were stratified into four groups based on clinical stages and underwent gut microbiota analysis. We established DKD mouse models and a healthy fecal microbiota transplantation (FMT) model to validate the effects of gut microbiota on DKD and select the potential harmful microbial community. Untargeted metabolome-microbiome combined analysis of mouse models helps decipher the pathogenetic mechanism from a metabolic perspective.

RESULTS

The diversity of the gut microbiome was significantly decreased in DKD patients when compared with that of the non-DKD population and was increased in the patients with more advanced DKD stages. The DKD severity in mice was relieved after healthy gut microbiota reconstruction. The common harmful microbial community was accumulated in the subjects with more severe DKD phenotypes (i.e., DKD and DKD5 patients and DKD mice). The harmful microbial community was positively associated with the serum injurious metabolites (e.g., cholic acid and hippuric acid).

CONCLUSION

The fecal microbial community was altered markedly in DKD. Combining the fecal analysis of both human and animal models selected the accumulated harmful pathogens. Partially recovering healthy gut microbiota can relieve DKD phenotypes via influencing pathogens' effect on DKD mice's metabolism.

Health Benefits and Side Effects of Short-Chain Fatty Acids

The gut microbiota and their metabolites could play an important role in health and diseases of human beings. Short-chain fatty acids (SCFAs) are mainly produced by gut microbiome fermentation of dietary fiber and could also be produced by bacteria of the skin and vagina. Acetate, propionate, and butyrate are three major SCFAs, and their bioactivities have been widely studied. The SCFAs have many health benefits, such as anti-inflammatory, immunoregulatory, anti-obesity, anti-diabetes, anticancer, cardiovascular protective, hepatoprotective, and neuroprotective activities. This paper summarizes health benefits and side effects of SCFAs with a special attention paid to the mechanisms of action. This paper provides better support for people eating dietary fiber as well as ways for dietary fiber to be developed into functional food to prevent diseases.