The role of the microbiome in NAFLD and NASH

Ganoderma lucidum spore oil attenuates acute liver injury by modulating lipid metabolism and gut microbiota

The incidence of acute liver injury is increasing and poses a significant threat to human health. Ganoderma lucidum spore oil (GLSO), a lipid substance extracted from Ganoderma lucidum spore powder using supercritical CO2 technology, has been investigated for its potential to prevent acute liver injury. However, the specific mechanism underlying the protective effects of GLSO remains incompletely understood. In this study, we investigated the preventive effect of GLSO on acute liver injury in rats, focusing on the gut microbiome and serum metabolomics. GLSO effectively alleviated liver dysfunction and reduced inflammation, leading to the prevention of acute liver injury in rats. Serum metabolomics analysis revealed that GLSO primarily modulated lipid metabolic pathways related to glycerophospholipid metabolism and sphingolipid metabolism. Specifically, GLSO decreased the levels of metabolites such as lysophosphatidylcholine (LPC), glycerophosphatidylcholine (GPC), and sphinganine 1-phosphate (SA1P), while increasing the levels of phosphatidylglycerol (PG) and digalactosylceramide (DGC). Gut microbiomics data indicated that GLSO effectively regulated the composition of the gut microbiota in rats with acute liver injury. Specifically, it increased the abundance of Firmicutes and decreased the abundance of Proteobacteria. Mantel test correlation analysis revealed a close relationship between gut microbial Burkholderiales and lipid metabolites in GLSO-mediated prevention of acute liver injury. GLSO exerts its preventive effects on acute liver injury by remodeling the gut microbiota and regulating lipid metabolism. These findings provide novel insights and potential directions for the development of new drugs targeting acute liver injury.

Therapeutic Role of Probiotics Against Environmental-Induced Hepatotoxicity: Mechanisms, Clinical Perspectives, Limitations, and Future

Hepatotoxicity is one of the biggest health challenges, particularly in the context of liver diseases, often aggravated by gut microbiota dysbiosis. The gut-liver axis has been regarded as a key idea in liver health. It indicates that changes in gut flora caused by various hepatotoxicants, including alcoholism, acetaminophen, carbon tetrachloride, and thioacetamide, can affect the balance of the gut's microflora, which may lead to increased dysbiosis and intestinal permeability. As a result, bacterial endotoxins would eventually enter the bloodstream and liver, causing hepatotoxicity and inducing inflammatory reactions. Many treatments, including liver transplantation and modern drugs, can be used to address these issues. However, because of the many side effects of these approaches, scientists and medical experts are still hoping for a therapeutic approach with fewer side effects and more positive results. Thus, probiotics have become well-known as an adjunctive strategy for managing, preventing, or reducing hepatotoxicity in treating liver injury. By altering the gut microbiota, probiotics offer a secure, non-invasive, and economical way to improve liver health in the treatment of hepatotoxicity. Through various mechanisms such as regulation of gut microbiota, reduction of pathogenic overgrowth, suppression of inflammatory mediators, modification of hepatic lipid metabolism, improvement in the performance of the epithelial barrier of the gut, antioxidative effects, and modulation of mucosal immunity, probiotics play their role in the treatment and prevention of hepatotoxicity. This review highlights the mechanistic effects of probiotics in environmental toxicants-induced hepatotoxicity and current findings on this therapeutic approach's experimental and clinical trials.

Iron overload exacerbates metabolic dysfunction-associated steatohepatitis via the microbiota-gut-liver axis through lipopolysaccharide-mediated Akr1b8 activation

Iron homeostatic is closely linked to the development of metabolic dysfunction-associated steatohepatitis (MASH). However, the underlying mechanisms remain poorly understood. HFE knockout (KO) mice were used to generate mild iron-overload models. MASH was induced by feeding mice a methionine- and choline-deficient (MCD) diet for 4 weeks. Iron overload significantly exacerbated the pathologies of MCD-induced MASH, including liver injury, hepatic lipid accumulation, inflammation, and fibrosis. Additionally, iron overload reshaped the composition of gut microbiota, and fecal microbiota transplantation assay proved that gut microbiota from iron-overload mice contributed to hepatic lipid accumulation in control mice. Furthermore, iron overload-induced dysbacteriosis altered the metabolite profiles, reducing short-chain fatty acid levels and increasing lipopolysaccharide (LPS) levels. Notably, elevated LPS levels upregulated the expression of aldo-keto reductase family 1 member B8 (Akr1b8), which accelerated lipid accumulation and inflammation in hepatocytes. Above results indicated that iron overload promoted MASH progression through the microbiota-gut-liver axis, mediated by LPS-induced activation of Akr1b8. These findings highlight the critical role of iron homeostasis and gut microbiota in MASH pathogenesis.

Salidroside attenuates NASH through regulating bile acid-FXR/TGR5 signaling pathway via targeting gut microbiota

Nonalcoholic steatohepatitis (NASH) is a significant threat to human health. Our previous study revealed that salidroside attenuated NASH and regulated the gut microbiota. However, whether the therapeutic effect of salidroside depends on gut microbiota remains to be determined. Therefore, we conducted further experiments to elucidate the essential functions of gut microbiota-associated metabolic pathways in the anti-NASH effects of salidroside. Our results showed that salidroside effectively alleviated lipid accumulation and inflammatory injury in NASH mice. 16S rRNA sequencing revealed that salidroside increased the abundance of Bacteroides. Mice receiving fecal microbiota transplantation (FMT) from salidroside-treated also presented less hepatic steatosis and higher abundance of Bacteroides. Antibiotics eliminated the effects of salidroside on hepatic steatosis and the gut microbiota. Mechanistically, salidroside and FMT from salidroside-treated altered the bile acid (BA) profile by decreasing the levels of conjugated BAs and tauro-α/β-muricholic acid and activated downstream farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5). Furthermore, we found that inhibitors of bile salt hydrolase (BSH) and FXR/TGR5 abolished the effects of salidroside and reduced downstream carnitine palmitoyltransferase 1α and lipoprotein lipase expression. These data demonstrate that salidroside attenuated NASH via gut microbiota-BA-FXR/TGR5 signaling pathway and reveal the underlying mechanism of salidroside on NASH.

Unveiling the Multifaceted Pharmacological Actions of Indole-3-Carbinol and Diindolylmethane: A Comprehensive Review

Cruciferae family vegetables are remarkably high in phytochemicals such as Indole-3-carbinol (I3C) and Diindolylmethane (DIM), which are widely known as nutritional supplements. I3C and DIM have been studied extensively in different types of cancers like breast, prostate, endometrial, colorectal, gallbladder, hepatic, and cervical, as well as cancers in other tissues. In this review, we summarized the protective effects of I3C and DIM against cardiovascular, neurological, reproductive, metabolic, bone, respiratory, liver, and immune diseases, infections, and drug- and radiation-induced toxicities. Experimental evidence suggests that I3C and DIM offer protection due to their antioxidant, anti-inflammatory, antiapoptotic, immunomodulatory, and xenobiotic properties. Apart from the beneficial effects, the present review also discusses the possible toxicities of I3C and DIM that are reported in various preclinical investigations. So far, most of the reports about I3C and DIM protective effects against various diseases are only from preclinical studies; this emphasizes the dire need for large-scale clinical trials on these phytochemicals against human diseases. Further, in-depth research is required to improve the bioavailability of these two phytochemicals to achieve the desirable protective effects. Overall, our review emphasizes that I3C and DIM may become potential drug candidates for combating dreadful human diseases.

Association of prebiotic/probiotic intake with MASLD: evidence from NHANES and randomized controlled trials in the context of prediction, prevention, and a personalized medicine framework

Objective

Metabolic-associated fatty liver disease (MASLD) is a growing global health concern. From the standpoint of preventive and personalized medicine, understanding the early determinants and modifiable risk factors is essential for targeted prevention and personalized treatment strategies. This study aimed to evaluate the specific association between probiotics/prebiotics and the occurrence of MASLD, contributing to the development of innovative preventive measures and personalized therapeutic approaches.

Methods

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018. The study employed logistic regression analysis to examine the relation between MASLD and probiotics/prebiotics. The efficacy of various MASLD predictive models was assessed using receiver operating characteristic (ROC) curves. A meta-analysis was conducted by searching databases up to 4 May 2024. The analysis included randomized controlled trials of liver function in patients with MASLD or nonalcoholic steatohepatitis treated with probiotics, prebiotics, or yogurt for a minimum of 6 months.

Results

A total of 5014 adults from NHANES were included in this study, with a weighted prevalence of MASLD observed at 24.47%. MASLD adults who consumed both probiotics and prebiotics exhibited a reduced risk of MASLD (OR = 0.71, 95% CI: 0.53 to 0.94). The use of probiotics/prebiotics can enhance the simplicity and practicality of the model. Model 1, adjusted for sex, BMI, race, and HEI-2015, achieved an area under the curve (AUC) of 0.8544, while Model 2, adjusted for sex, BMI, race, and prebiotics/probiotics use, showed a similar AUC of 0.8537. The comparison between the two models revealed no statistically significant difference (0.8544 vs. 0.8537; 95% CI: - 0.0010 to 0.0025; Z = 0.8332; p = 0.4047). Subgroup analysis of the NHANES data revealed that individuals aged 40 and older benefit from consuming probiotics or prebiotics. Furthermore, the meta-analysis demonstrated that probiotic or prebiotic interventions resulted in significant improvements in biochemical markers, including alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein cholesterol, and triglycerides.

Conclusions

The consumption of probiotics/prebiotics has been linked to a reduced risk of developing MASLD in adults. Integrating probiotics/prebiotics into early intervention and personalized treatment plans may facilitate targeted prevention and management of MASLD, promoting a more individualized approach to disease prevention and care.

Supplementary information

The online version contains supplementary material available at 10.1007/s13167-025-00398-4.

Association of blood manganese and selenium levels with hepatic steatosis among adolescents: a nationwide cross-sectional analysis

Objective

This study aimed to investigate the association between blood manganese and selenium levels and hepatic steatosis among adolescents, using data from the National Health and Nutrition Examination Survey (NHANES) 2017-2023.

Methods

A cross-sectional analysis was conducted using data from 2,459 adolescents (aged 12-19 years) with complete data on liver ultrasound transient elastography, blood manganese, and selenium levels. Hepatic steatosis was defined as a controlled attenuation parameter (CAP) score of ≥248 dB/m, a measure of liver steatosis, which is a primary characteristic and a less severe stage of hepatic steatosis, assessed by vibration-controlled transient elastography (VCTE). Multivariate logistic regression models were used to assess the associations between blood manganese and selenium levels and hepatic steatosis, while restricted cubic splines (RCS) were employed to examine the dose-response relationships.

Results

The mean age of the participants was 15.37 years, with 52.22% boy. Higher blood manganese and selenium levels were significantly associated with an increased prevalence of hepatic steatosis. In the fully adjusted model, adolescents in the highest quartile of blood manganese had more than twice the odds of hepatic steatosis compared to those in the lowest quartile (OR = 2.41, 95% CI: 1.55-3.75, P < 0.01). Similarly, the highest quartile of blood selenium was associated with a 57% increase in hepatic steatosis prevalence compared to the lowest quartile (OR = 1.57, 95% CI: 1.19-2.08, P < 0.01). RCS analysis confirmed a linear association between both blood manganese and selenium levels and hepatic steatosis prevalence. Subgroup analyses did not reveal statistically significant interactions by age, sex, or obesity status, although associations appeared stronger in younger adolescents.

Conclusion

Elevated blood manganese and selenium levels are associated with a higher prevalence of hepatic steatosis in adolescents. These findings suggest a potential role of trace elements in the development of hepatic steatosis, highlighting the need for further research to better understand the underlying mechanisms involved in liver fat accumulation in this population.

Dual GIP and GLP-1 receptor agonist tirzepatide alleviates hepatic steatosis and modulates gut microbiota and bile acid metabolism in diabetic mice

Tirzepatide is a dual agonist of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors and is a promising therapeutic option for type 2 diabetes mellitus (T2DM). Nevertheless, its effect and underlying mechanism on hepatic steatosis remain ambiguous. Herein, we explored the impact of tirzepatide on improving hepatic steatosis in diabetic mice, with a particular focus on the gut microbiota and bile acids (BAs) using animal models. The tirzepatide effectively reduced body weight, improved insulin resistance, decreased serum and hepatic lipid levels, and mitigated liver injury. Compared to semaglutide, tirzepatide exhibited superior efficacy in reducing hepatic lipid accumulation. 16S rRNA gene sequencing and targeted metabolomics of BAs revealed that tirzepatide ameliorated gut microbiota dysbiosis and BAs metabolism in diabetic mice. Notably, tirzepatide observably increased the abundance of beneficial genera such as Akkermansia, elevated the ratio of farnesoid X receptor (FXR) antagonists (glycoursodeoxycholic acid: GUDCA, β-muricholic acid: β-MCA, hyodeoxycholic acid: HDCA, ursodeoxycholic acid: UDCA) to natural agonists (cholic acid: CA, lithocholic acid: LCA, chenodeoxycholic acid: CDCA, glycocholic acid: GCA, taurodeoxycholic acid: TDCA), and reduced FXR expression in intestinal tissues. In conclusion, tirzepatide attenuated hepatic steatosis in diabetic mice and regulated the gut microbiota and BAs metabolism, which may help to provide a novel therapeutic approach and therapeutic target for metabolic dysfunction-associated steatotic liver disease (MASLD).

Polysaccharides from hawthorn fruit alleviate high-fat diet-induced NAFLD in mice by improving gut microbiota dysbiosis and hepatic metabolic disorder

BACKGROUND

Hawthorn fruit, renowned as both a functional food and herbal medicine with lipid-lowering effects, is abundant in polysaccharides. However, there is limited research on the effects and mechanisms of hawthorn fruit polysaccharides (HP) in addressing non-alcoholic fatty liver disease (NAFLD).

PURPOSE

This study aims to investigate the effects of HP on NAFLD both in vivo and in vitro, and to elucidate the underlying mechanisms by which HP exerts its anti-NAFLD activity.

METHODS

NAFLD mice induced by a high-fat diet were employed as the in vivo model, while oleate/palmitate-induced HepG2 cells served as the in vitro model. H&E and Oil Red O staining were employed to examine fat accumulation in hepatocytes. Serum aminotransferase (ALT), aspartate aminotransferase (AST), hepatic malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) were measured using corresponding ELISA kits. Hepatic metabolomics analysis based on UHPLC-QTOF/MS was utilized to examine the role of HP in improving hepatic metabolic disorders. 16S rRNA sequencing was conducted to explore the effect of HP in alleviating gut microbiota dysbiosis. GC-MS was applied to detect short-chain fatty acids (SCFAs) to clarify the impact of HP in NAFLD mice.

RESULTS

HP significantly inhibited weight gain and hepatic fat accumulation in NAFLD mice. The reduction in serum ALT and AST levels indicated that HP mitigated liver function damage, while the decreased MDA levels and increased SOD activity suggested that HP alleviated hepatic oxidative stress. Furthermore, HP diminished the release of inflammatory cytokines such as IL-1β and IL-6 in the liver. HP significantly regulated metabolic pathways related to amino acids, lipids, and vitamins. Key metabolites such as l-tyrosine, urocanic acid, undecanedioic acid, oleamide, vitamin A, and vitamin B7 were restored to near-normal levels under the regulatory effects of HP. Gut microbiota dysbiosis in NAFLD mice was also ameliorated by HP, with genera such as unclassified_f__Lachnospiraceae and Dubosiella being notably affected. Correlation analysis indicated a significant correlation between the regulatory effects of HP on liver metabolism and gut microbiota. Additionally, HP showed no effect in vitro but increased acetic acid level in the gut of NAFLD mice.

CONCLUSIONS

These findings demonstrate that HP exhibits its anti-NAFLD effects, including alleviating lipid accumulation, liver dysfunction, oxidative stress, and inflammation. Mechanistically, HP primarily improves gut microbiota dysbiosis, thereby elevating intestinal SCFA levels and restoring hepatic metabolic disorders in NAFLD mice.

Structural characterization of a α-d-glucan from Ginkgo biloba seeds and its protective effects on non-alcoholic fatty liver disease in mice

Nonalcoholic fatty liver disease (NAFLD) poses a great global challenge to public health, yet it holds promise for amelioration through plant-derived polysaccharide. Ginkgo biloba seeds have long been used as medicine and food, which has potential benefits for various chronic diseases. However, the protective role of Ginkgo biloba seed polysaccharide against NAFLD remains unclear. In this study, we isolated and purified polysaccharide (GBSP-2) from Ginkgo biloba seeds. GBSP-2 is composed of α-d-glucopyranose residues, which are interconnected with α-d-glucopyranose units linked by (1→4) bonds, (1→4,6) bonds and (1→3,4) bonds, the ratio distribution is 15:1:1. By studying a mouse model, we investigated the effect of GBSP-2 (100 or 200 mg/kg) on high-fat-diet-induced NAFLD. We demonstrated that GBSP-2 significantly alleviated NAFLD, as evidenced by reduced hepatic steatosis, decreased inflammation, improved oxidative stress and ameliorative glucolipid metabolic disorders. Furthermore, GBSP-2 mitigated gut microbiota disturbance of NAFLD mice and markedly increased the abundance of Akkermansia, Romboutsia, Lactobacillus and Bacteroides. Mechanistically, GBSP-2 could activate AMPK/ACC signaling pathway to inhibit lipid synthesis by generating 3,4-dihydroxyphenylpropionic acid (DHPPA). Overall, these findings suggest that GBSP-2 plays a multi-channel and multi-target role in improving NAFLD through the gut-liver axis.

Research hotspots and trends in gut microbiota and nonalcoholic fatty liver disease: A bibliometric study

BACKGROUND

Recent research indicates that the intestinal microbial community, known as the gut microbiota, may play a crucial role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). To understand this relationship, this study used a comprehensive bibliometric analysis to explore and analyze the currently little-known connection between gut microbiota and NAFLD, as well as new findings and possible future pathways in this field.

AIM

To provide an in-depth analysis of the current focus issues and research developments on the interaction between gut microbiota and NAFLD.

METHODS

In this study, all data were collected from the Web of Science Core Collection, and the related searches were completed on one day (February 21, 2024). The data were stored in plain text format to facilitate subsequent analysis. VOSviewer 1.6.20 and CiteSpace 6.1R6 Basic were used for knowledge graph construction and bibliometric analysis.

RESULTS

The study included a total of 1256 articles published from 2013 to 2023, and the number of published papers demonstrated an upward trend, reaching a peak in the last two years. The University of California, San Diego held the highest citation count, while Shanghai University of Traditional Chinese Medicine in China led in the number of published works. The journal "Nutrients" had the highest publication count, while "Hepatology" was the most frequently cited. South Korean author Suk Ki Tae was the most prolific researcher. The co-cited keyword cluster labels revealed ten major clusters, namely cortisol, endothelial dysfunction, carbohydrate metabolism, myocardial infarction, non-alcoholic steatohepatitis, lipotoxicity, glucagon-like peptide-1, non-islet dependent, ethnicity, and microRNA. Keyword outbreak analysis highlighted metabolic syndrome, hepatic steatosis, insulin resistance, hepatocellular carcinoma, cardiovascular disease, intestinal permeability, and intestinal bacterial overgrowth as prominent areas of intense research.

CONCLUSION

Through the quantitative analysis of relevant literature, the current research focus and direction of gut microbiota and NAFLD can be more clearly understood, which helps us better understand the pathogenesis of NAFLD, and also opens up innovative solutions and strategies for the treatment of NAFLD.

Discovery of robust and highly specific microbiome signatures of non-alcoholic fatty liver disease

BACKGROUND

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) with a global prevalence of 30% is multifactorial and the involvement of gut bacteria has been recently proposed. However, finding robust bacterial signatures of NAFLD has been a great challenge, mainly due to its co-occurrence with other metabolic diseases.

RESULTS

Here, we collected public metagenomic data and integrated the taxonomy profiles with in silico generated community metabolic outputs, and detailed clinical data, of 1206 Chinese subjects w/wo metabolic diseases, including NAFLD (obese and lean), obesity, T2D, hypertension, and atherosclerosis. We identified highly specific microbiome signatures through building accurate machine learning models (accuracy = 0.845-0.917) for NAFLD with high portability (generalizable) and low prediction rate (specific) when applied to other metabolic diseases, as well as through a community approach involving differential co-abundance ecological networks. Moreover, using these signatures coupled with further mediation analysis and metabolic dependency modeling, we propose synergistic defined microbial consortia associated with NAFLD phenotype in overweight and lean individuals, respectively.

CONCLUSION

Our study reveals robust and highly specific NAFLD signatures and offers a more realistic microbiome-therapeutics approach over individual species for this complex disease. Video Abstract.

Host-derived Bacillus antagonistic novel duck reovirus infection by regulating gut microbiota-mediated immune responses

The Novel Duck Reovirus (NDRV) infection poses a significant health risk to ducks, primarily attributed to the absence of efficacious preventive measures. This research aimed to investigate whether the administration of isolated Bacillus could protect antagonistic NDRV infection in a Cherry Valley duck model. Four indigenous Bacillus strains from the feces of healthy ducks demonstrated promising biosafety profiles. One-day-old ducklings were inoculated intramuscularly with NDRV and subsequently subjected to a 28-day regimen of mixed Bacillus (Bac) treatment. The effects of Bac on pathological symptoms, immune response and intestinal flora were analyzed. The results showed that Bac significantly reduced weight loss, clinical symptoms, and viral loading. Moreover, Bac treatment significantly decreased neutrophils, monocytes proportion, the TNF-α, IL-1β and IL-6 expression, increased platelets, lymphocytes proportion, the IFN-β and IL-10 expression, and restored immune dysfunction. In addition, Bac has increased the relative abundance of Enterococcaceae, Lactobacillales, Bacilli, Ruminococcaceae, Clostridium and Phascolarctobacterium. Moreover, the metabolism of short-chain fatty acids (SCFAs) was further regulated, thereby enhancing the acetate content. The correlation analysis showed that a positive association between acetate levels and IFN-β expression, while a negative correlation was observed with viral loading. In conclusion, the results suggest that the anti-NDRV mechanism of Bac may involve the modulation of gut microbiota to elicit an immune response that inhibits viral infection. This study presents a novel approach for the prevention and treatment of NDRV, thereby establishing a theoretical foundation for the future development of probiotics in the prevention and treatment of NDRV.

Gut‑liver axis in liver disease: From basic science to clinical treatment (Review)

Incidence of a number of liver diseases has increased. Gut microbiota serves a role in the pathogenesis of hepatitis, cirrhosis and liver cancer. Gut microbiota is considered 'a new virtual metabolic organ'. The interaction between the gut microbiota and liver is termed the gut‑liver axis. The gut‑liver axis provides a novel research direction for mechanism of liver disease development. The present review discusses the role of the gut‑liver axis and how this can be targeted by novel treatments for common liver diseases.

Regulatory Roles of Quercetin in Alleviating Fructose-Induced Hepatic Steatosis: Targeting Gut Microbiota and Inflammatory Metabolites

While fructose is a key dietary component, concerns have been raised about its potential risks to the liver. This study aimed to assess quercetin's protective effects against fructose-induced mouse hepatic steatosis. Thirty-two male C57BL/6J mice were randomly allocated into four groups: control, high fructose diet (HFrD), HFrD supplemented with low-dose quercetin (HFrD+LQ), and HFrD supplemented with high-dose quercetin (HFrD+HQ). Biochemical, pathological, immune, and metabolic parameters were assessed. Quercetin treatment significantly reduced liver fat percentages in mice on a high fructose diet, with the most notable reduction observed in the HFrD+HQ group. Histological examination confirmed this reduction, revealing diminished lipid droplets and decreased inflammation and steatosis in hepatocytes. Compared to the high fructose group, interleukin-1 β and tumor necrosis factor alpha were significantly decreased, serum aspartate aminotransferase concentrations were markedly reduced, and blood high-density lipoprotein concentrations were substantially elevated after quercetin intervention (p < 0.05). Total bilirubin and triglyceride levels, which were significantly altered following high fructose intervention and reversed after quercetin intervention. Following the administration of 100 mg/kg quercetin, the Firmicutes/Bacteroidetes ratio was significantly reduced compared to the high fructose group. At the genus level, Erysipelotrichaceae_uncultured, Faecalibaculum, Odoribacter, and Allobaculum were significantly decreased (p < 0.05), Lacnospiraceae NK4A136 group, Parabacteroides, and Alloprevotella significantly increased (p < 0.05). However, the 50 mg/kg quercetin treatment only decreased the abundance of Erysipelotrichaceae_uncultured (p < 0.05). In addition, quercetin significantly enhanced the content of propionic acid and total acid (p < 0.05). Moreover, the intestinal flora showed a significant correlation with the hepatic health-related phenotype in mice. Both 50 and 100 mg/kg quercetin treatments significantly mitigated liver fat deposition in mice with fructose-induced hepatic steatosis. However, the higher dose of quercetin (100 mg/kg) demonstrated a more pronounced effect in reducing liver inflammation, likely due to its impact on gut microbiota regulation. This suggests quercetin's potential as a therapeutic agent for fructose-related hepatic steatosis, emphasizing the importance of dose considerations.

The possible protective effect of luteolin on cardiovascular and hepatic changes in metabolic syndrome rat model

The metabolic syndrome, or MetS, is currently a global health concern. The anti-inflammatory, anti-proliferative, and antioxidant properties of luteolin are some of its advantageous pharmacological characteristics. This research was designed to establish a MetS rat model and investigate the possible protective effect of luteolin on cardiovascular, hepatic, and metabolic changes in diet-induced metabolic syndrome in rats. Forty adult male albino rats were split into four groups: a negative control group, a group treated with luteolin, a group induced MetS (fed 20% fructose), and a group treated with luteolin (fed 20% fructose and given luteolin). Following the experiment after 8 weeks, biochemical, histological (light and electron), and immunohistochemistry analyses were performed on liver and heart tissues. Serum levels of cTnI, CK-MB, and LDH were significantly elevated in response to the cardiovascular effect of MetS. Furthermore, compared to the negative control group, the MetS group showed a marked increase in lipid peroxidation in the cardiac and hepatic tissues, as evidenced by elevated levels of MDA and a decline in the antioxidant defense system, as demonstrated by lower activities of GSH and SOD. The fatty liver-induced group exhibited histological alterations, including disrupted hepatic architecture, dilated and congested central veins, blood sinusoids, and portal veins. In addition to nuclear structural alterations, most hepatocytes displayed varying degrees of cytoplasmic vacuolation, mitochondrial alterations, and endoplasmic reticulum dilatation. These alterations were linked to inflammatory cellular infiltrations, collagen fiber deposition, active hepatic stellate cells, and scattered hypertrophied Kupffer cells, as demonstrated by electron microscopy and validated by immunohistochemical analysis. It is interesting to note that eosinophils were seen between the liver cells and in dilated blood sinusoids. Moreover, the biochemical (hepatic and cardiac) and histological (liver) changes were significantly less severe in luteolin-treated rat on a high-fructose diet. These results suggested that luteolin protects against a type of metabolic syndrome that is produced experimentally.

Intestinal TM6SF2 protects against metabolic dysfunction-associated steatohepatitis through the gut-liver axis

Transmembrane-6 superfamily member 2 (TM6SF2) regulates hepatic fat metabolism and is associated with metabolic dysfunction-associated steatohepatitis (MASH). TM6SF2 genetic variants are associated with steatotic liver disease. The pathogenesis of MASH involves genetic factors and gut microbiota alteration, yet the role of host-microbe interactions in MASH development remains unclear. Here, we discover that mice with intestinal epithelial cell-specific knockout of Tm6sf2 (Tm6sf2ΔIEC) develop MASH, accompanied by impaired intestinal barrier and microbial dysbiosis. Transplanting stools from Tm6sf2ΔIEC mice induces steatohepatitis in germ-free recipient mice, whereas MASH is alleviated in Tm6sf2ΔIEC mice co-housed with wild-type mice. Mechanistically, Tm6sf2-deficient intestinal cells secrete more free fatty acids by interacting with fatty acid-binding protein 5 to induce intestinal barrier dysfunction, enrichment of pathobionts, and elevation of lysophosphatidic acid (LPA) levels. LPA is translocated from the gut to the liver, contributing to lipid accumulation and inflammation. Pharmacological inhibition of the LPA receptor suppresses MASH in both Tm6sf2ΔIEC and wild-type mice. Hence, modulating microbiota or blocking the LPA receptor is a potential therapeutic strategy in TM6SF2 deficiency-induced MASH.

Advanced microbiome therapeutics as a novel modality for oral delivery of peptides to manage metabolic diseases

The rising prevalence of metabolic diseases calls for innovative treatments. Peptide-based drugs have transformed the management of conditions such as obesity and type 2 diabetes. Yet, challenges persist in oral delivery of these peptides. This review explores the potential of 'advanced microbiome therapeutics' (AMTs), which involve engineered microbes for delivery of peptides in situ, thereby enhancing their bioavailability. Preclinical work on AMTs has shown promise in treating animal models of metabolic diseases, including obesity, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease. Outstanding challenges toward realizing the potential of AMTs involve improving peptide expression, ensuring predictable colonization control, enhancing stability, and managing safety and biocontainment concerns. Still, AMTs have potential for revolutionizing the treatment of metabolic diseases, potentially offering dynamic and personalized novel therapeutic approaches.

Shear Wave Dispersion Elastography in ALD and MASLD: Comparative Pathophysiology and Clinical Potential-A Narrative Review

Alcohol-related liver disease (ALD) is a major cause of global morbidity and mortality, progressing from steatosis to cirrhosis and hepatocellular carcinoma. While liver biopsy remains the gold standard for identifying liver disease, non-invasive methods like shear wave dispersion (SWD) elastography offer promising alternatives. This scoping review evaluates SWD's potential in the study of ALD, comparing it to metabolic dysfunction-associated steatotic liver disease (MASLD). SWD measures changes in shear wave speed in relation to liver viscosity and necroinflammation. Studies in MASLD suggest that SWD effectively correlates with fibrosis and inflammation stages, but its application in ALD remains underexplored. Both ALD and MASLD show similar inflammatory and fibrotic pathways, despite having different etiologies and histological features. This review emphasizes the necessity to identify ALD-specific SWD reference values and verify SWD's ability to improve diagnosis and disease progression. Prospective studies comparing SWD findings with histological benchmarks in ALD are essential for establishing its clinical utility. Incorporating SWD into clinical practice could revolutionize the non-invasive evaluation of ALD, offering a safer, cost-effective, and repeatable diagnostic tool.

Association between bowel movement frequency, stool consistency and MAFLD and advanced fibrosis in US adults: a cross-sectional study of NHANES 2005-2010

BACKGROUND

Although previous studies have established associations between specific gut microbiota (GM) and metabolic dysfunction-associated fatty liver disease (MAFLD), research examining the relationship between functional gastrointestinal symptoms and MAFLD, including advanced fibrosis, remains limited. This study aims to investigate the association between stool consistency, bowel movement frequency (BMF), and the occurrence of MAFLD and advanced fibrosis in U.S. adults.

METHODS

This population-based study included 9,928 adults from the 2005-2010 National Health and Nutrition Examination Survey (NHANES), with a mean age of 47.19 ± 16.65 years, comprising 47.7% males and 52.3% females. Weighted logistic regression was used to assess the association between stool consistency, BMF, and MAFLD or advanced fibrosis. A linear trend was assessed by treating BMF categories as continuous variables with ordinal values. The dose-response relationship between BMF and MAFLD was analyzed using restricted cubic splines (RCS) regression. Sensitivity and subgroup analyses were performed to confirm the robustness of the findings.

RESULTS

In the RCS regression, no significant nonlinear relationship was observed between BMF and the risk of MAFLD (p-overall < 0.0001; p-nonlinear = 0.0663). The multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for MAFLD were 0.82 (95% CI 0.69-0.98), 1.31 (95% CI 1.16-1.46), and 1.50 (95% CI 1.14-1.99) for participants with 3-6 BMs/week, 1-2 BMs/day, and > 2 BMs/day, respectively, compared to those with once/day (p-trend < 0.001). For stool consistency, hard stools were associated with a decreased risk of MAFLD (OR 0.77; 95% CI 0.62-0.95), whereas loose stools increased the risk (OR 1.37; 95% CI 1.05-1.80), relative to normal stools. A significant interaction between BMF and age was observed. No significant associations were found between stool consistency or BMF and advanced liver fibrosis. Sensitivity analyses confirmed the robustness of these findings.

CONCLUSIONS

This cross-sectional study demonstrates that a BMF of 3-6 BMs/week and hard stools are associated with a reduced risk of MAFLD, whereas a BMF of more than once/day and loose stools are linked to an increased risk of MAFLD. Moreover, no significant associations were observed between stool consistency, BMF, and advanced fibrosis among individuals diagnosed with MAFLD.

CLINICAL TRIAL NUMBER

Not applicable.

Small intestinal bacterial overgrowth and metabolic dysfunction-associated steatotic liver disease

Small intestinal bacterial overgrowth (SIBO), characterized by alterations in both the type and quantity of bacteria in the small intestine, leads to impaired intestinal digestion and absorption that can cause a range of clinical symptoms. Recent studies have identified significant changes in the composition of the small intestinal microbiota and metabolomic profiles of patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This study systematically reviewed and synthesized the available data to explore the association between SIBO and MASLD. Comprehensive literature searches of the Embase, PubMed, Web of Science, Ovid, and Cochrane databases were conducted. Article quality screening was performed using the Newcastle-Ottawa Quality Assessment Scale. Cross-sectional, cohort, and case-control studies were included. A total of 7,200 articles were initially screened, of which 14 were ultimately included for analysis. Individuals with SIBO in both the MASLD and non-MASLD groups were extracted and a chi-square test was performed to calculate the odds ratio (OR) and 95% confidence interval (CI). The I2 index was used to measure heterogeneity. For heterogeneity >50%, a random effects model was used. There was a clear association between SIBO and MASLD (OR = 3.09; 95% CI 2.09-4.59, I 2 = 66%, p < 0.0001). Subgroup analyses by MASLD stage showed that the probability of SIBO positivity increased with MASLD lesion severity. After stratifying by the diagnostic methods for SIBO and MASLD, the meta-analysis results suggest a reduction in inter-group heterogeneity. For the MASLD subgroup diagnosed via liver biopsy, the OR was 4.89. A subgroup analysis of four studies that included intestinal permeability testing revealed an OR of 3.86 (95% CI: 1.80-8.28, I 2 = 9%, p = 0.0005). A meta-regression analyses revealed that both race and regional development level significantly influenced the relationship between SIBO and MASLD (p = 0.010, p = 0.047). In conclusion, this meta-analyses provides strong evidence that SIBO may contribute to the development and progression of MASLD. The strongest associations were observed between lactulose breath testing, gut microbiota culture, liver biopsy diagnosis of MASLD, and SIBO detected through intestinal permeability testing. The primary sources of heterogeneity are race and developed regions.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=427040.

Potential mechanism of perillaldehyde in the treatment of nonalcoholic fatty liver disease based on network pharmacology and molecular docking

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic metabolic liver diseases worldwide. Perillaldehyde (4-propyl-1-en-2-ylcyclohexene-1-aldehyde, PA) is a terpenoid compound extracted from Perilla, which has effective pharmacological activities such as anti-inflammatory, antidepressant, and anticancer. This study aimed to explore the pharmacological effects of PA in intervening with NAFLD and reveal its potential mechanisms. Firstly, we identified the core targets of PA intervention therapy for NAFLD through network pharmacology and molecular docking techniques. After that, in vitro animal experiments such as H&E and Masson staining, immunofluorescence, immunohistochemistry, and Western blot were conducted to validate the results network effectively pharmacology predicted. Network pharmacology analysis suggested that PPAR-α may be the core target of PA intervention in NAFLD. H&E and Masson staining showed that after low-dose (50 mg/kg) PA administration, there was a noticeable improvement in fat deposition in the livers of NAFLD mice, and liver tissue fibrosis was alleviated. Immunohistochemical and immunofluorescence analysis showed that low dose (50 mg/kg) PA could reduce hepatocyte apoptosis, decrease the content of pro-apoptosis protein Bax, and increase the expression of anti-apoptosis protein Bcl-2 in NAFLD mice. Western blot results confirmed that low-dose (50 mg/kg) PA could increase the expression of PPAR-α and inhibit the expression of NF-κB in NAFLD mice. Our study indicated that PA could enhance the activity of PPAR-α and reduce the level of NF-κB in NAFLD mice, which may positively affect the prevention of NAFLD.

Lactobacillus sp. for the Attenuation of Metabolic Dysfunction-Associated Steatotic Liver Disease in Mice

Probiotics are studied for their therapeutic potential in the treatment of several diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). Part of the significant progress made in understanding the pathogenesis of steatosis has come from identifying the complex interplay between the gut microbiome and liver function. Recently, probiotics have shown beneficial effects for the treatment and prevention of steatosis and MASLD in rodent models and in clinical trials. Numerous studies have demonstrated the promising potential of lactic acid bacteria, especially the genus Lactobacillus. Lactobacillus is a prominent bile acid hydrolase bacterium that is involved in the biotransformation of bile acids. This genus' modulation of the gut microbiota also contributes to overall gut health; it controls gut microbial overgrowth, shapes the intestinal bile acid pool, and alleviates inflammation. This narrative review offers a comprehensive summary of the potential of Lactobacillus in the gut-liver axis to attenuate steatosis and MASLD. It also highlights the roles of Lactobacillus in hepatic lipid metabolism, insulin resistance, inflammation and fibrosis, and bile acid synthesis in attenuating MASLD.

The oral microbial odyssey influencing chronic metabolic disease

INTRODUCTION

Since the oral cavity is the gateway to the gut, oral microbes likely hold the potential to influence metabolic disease by affecting the gut microbiota.

METHOD

A thorough review of literature has been performed to link the alterations in oral microbiota with chronic metabolic disease by influencing the gut microbiota.

RESULT

A strong correlation exists between abnormalities in oral microbiota and several systemic disorders, such as cardiovascular disease, diabetes, and obesity, which likely initially manifest as oral diseases. Ensuring adequate oral hygiene practices and cultivating diverse oral microflora are crucial for the preservation of general well-being. Oral bacteria have the ability to establish and endure in the gastrointestinal tract, leading to the development of prolonged inflammation and activation of the immune system. Oral microbe-associated prophylactic strategies could be beneficial in mitigating metabolic diseases.

CONCLUSION

Oral microbiota can have a profound impact on the gut microbiota and influence the pathogenesis of metabolic diseases.

Modulation of gut microbiota by probiotics to improve the efficacy of immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma, a common malignancy of the digestive system, typically progresses through a sequence of hepatitis, liver fibrosis, cirrhosis and ultimately, tumor. The interaction between gut microbiota, the portal venous system and the biliary tract, referred to as the gut-liver axis, is crucial in understanding the mechanisms that contribute to the progression of hepatocellular carcinoma. Mechanisms implicated include gut dysbiosis, alterations in microbial metabolites and increased intestinal barrier permeability. Imbalances in gut microbiota, or dysbiosis, contributes to hepatocellular carcinoma by producing carcinogenic substances, disrupting the balance of the immune system, altering metabolic processes, and increasing intestinal barrier permeability. Concurrently, accumulating evidence suggests that gut microbiota has the ability to modulate antitumor immune responses and affect the efficacy of cancer immunotherapies. As a new and effective strategy, immunotherapy offers significant potential for managing advanced stages of hepatocellular carcinoma, with immune checkpoint inhibitors achieving significant advancements in improving patients' survival. Probiotics play a vital role in promoting health and preventing diseases by modulating metabolic processes, inflammation and immune responses. Research indicates that they are instrumental in boosting antitumor immune responses through the modulation of gut microbiota. This review is to explore the relationship between gut microbiota and the emergence of hepatocellular carcinoma, assess the contributions of probiotics to immunotherapy and outline the latest research findings, providing a safer and more cost-effective potential strategy for the prevention and management of hepatocellular carcinoma.

Rifaximin alleviates MCD diet-induced NASH in mice by restoring the gut microbiota and intestinal barrier

AIMS

Due to the increasing global incidence rate of nonalcoholic steatohepatitis (NASH) combined with the lack of effective treatment methods for this disease, there is an urgent need to find new treatment strategies. The aim of this study was to investigate the efficacy of rifaximin in preventing and treating NASH and the related mechanism.

MATERIALS AND METHODS

A NASH model was constructed by feeding male C57BL/6 mice a methionine-choline-deficient (MCD) diet for 4 weeks. Rifaximin was administered for 1 week before MCD diet feeding or during the last week of MCD diet feeding to investigate its preventive or therapeutic effects. Liver pathology, hepatic enzyme levels and metabolic indices were measured to evaluate the effects of rifaximin on NASH. Intestinal barrier integrity was measured via the Ussing chamber system and western blotting. 16S rDNA sequencing was conducted to investigate the fecal microbiota composition. Western blotting was performed to evaluate peroxisome proliferator activated receptor (PPAR)α and PPARγ protein levels.

KEY FINDINGS

Rifaximin effectively alleviated MCD diet-induced NASH. The microbiota composition in MCD diet-fed mice was significantly altered, and intestinal barrier integrity was disrupted. Dysbiosis and intestinal barrier dysfunction were reversed by rifaximin. In addition, rifaximin modulated PPARα and PPARγ expression in the liver.

SIGNIFICANCE

Rifaximin effectively alleviated MCD diet-induced NASH by restoring the gut microbiota and reversing intestinal barrier dysfunction, suggesting that rifaximin treatment is a new approach for preventing and treating NASH.

Integrated serum metabolomics, 16S rRNA sequencing and bile acid profiling to reveal the potential mechanism of gentiopicroside against nonalcoholic steatohepatitis in lean mice

ETHNOPHARMACOLOGICAL RELEVANCE

Lean nonalcoholic steatohepatitis (NASH) poses a serious threat to public health worldwide. Herbs of the genus Gentiana have been used for centuries to treat hepatic disease or have been consumed for hepatic protection efficiency. Gentiopicroside (GPS), the main bioactive component of Gentiana herbs, has been shown to be beneficial for protecting the liver, improving intestinal disorders, modulating bile acid profiles, ameliorating alcoholic hepatosteatosis, and so on. It is plausible to speculate that GPS may hold potential as a therapeutic strategy for lean NASH. However, no related studies have been conducted thus far.

AIM OF THE STUDY

The present work aimed to investigate the benefit of GPS on NASH in a lean mouse model.

MATERIALS AND METHODS

NASH in a lean mouse model was successfully established via a published method. GPS of 50 and 100 mg/kg were orally administered to verify the effect. Untargeted metabolomics, 16S rDNA sequencing and bile acid (BA) profiling, as well as qPCR and Western blotting analysis were employed to investigate the mechanism underlying the alleviating effect.

RESULTS

GPS significantly reduced the increase in serum biochemicals and liver index, and attenuated the accumulation of fat in the livers of lean mice with NASH. Forty-two potential biomarkers were identified by metabolomics analysis, leading to abnormal metabolic pathways of primary bile acid biosynthesis and fatty acid biosynthesis, which were subsequently rebalanced by GPS. A decreased Firmicutes/Bacteroidetes (F/B) ratio and disturbed BA related GM profiles were revealed in lean mice with NASH but were partially recovered by GPS. Furthermore, serum profiling of 23 BAs confirmed that serum BA levels were elevated in the lean model but downregulated by GPS treatment. Pearson correlation analysis validated associations between BA profiles, serum biochemical indices and related GM. qPCR and Western blotting analysis further elucidated the regulation of genes associated with liver lipid synthesis and bile acid metabolism.

CONCLUSIONS

GPS may ameliorate steatosis in lean mice with NASH, regulating the metabolomic profile, BA metabolism, fatty acid biosynthesis, and BA-related GM. All these factors may contribute to its beneficial effect.

PAMK Ameliorates Non-Alcoholic Steatohepatitis and Associated Anxiety/Depression-like Behaviors Through Restoring Gut Microbiota and Metabolites in Mice

OBJECTIVES

Long-term Western diet-induced non-alcoholic steatohepatitis (NASH) can lead to liver cirrhosis and NASH-associated hepatocellular carcinoma, which are end-stage liver diseases. Meanwhile, NASH is associated with mental burden and worsens as the disease progresses. Atractylodes Macrocephala Koidz (AMK) is one of the main ingredients of Shenling Baizhu San, and the effect of Polysaccharide from AMK ameliorates (PAMK), as an important medicinal ingredient of AMK, on NASH and associated anxiety/depression-like behaviors is still unclear.

METHODS

This study investigated the protective effect of PAMK on NASH and associated anxiety/depression-like behaviors through a Western diet-induced NASH mice model.

RESULTS

showed that PAMK decreased the concentrations of liver TC, TG, and serum AST and ALT, improving glucose tolerance, and reducing liver steatosis and fibrosis. Moreover, the expression of liver IL-6, IL-1β, TNF-α, IL-18 and MCP-1 could be reduced by PAMK significantly. Additionally, PAMK decreased anxiety/depression-like behaviors and expression of IL-6, IL-1β, TNF-α, and MCP-1 in the hippocampus. 16S rRNA gene sequencing revealed that PAMK diminished the Firmicutes/Bacteroidetes ratio and abundance of Faecalibaculum_rodentium, and increased the abundance of Muribaculaceae. This might be related to gene abundance of Pentose, the glucuronate interconversions pathway and carbohydrate enzymes (GH1, GH4). Serum metabolomics suggested that PC (18:5e/2:0), PC (16:2e/2:0), Lysopc 20:4, PC (16:0/2:0), and LPC 19:0 upregulated significantly after PAMK intervention, together with the enrichment of carbon metabolism and Citrate cycle pathways specially.

CONCLUSIONS

PAMK as a potential prebiotic ameliorated NASH and associated anxiety/depression-like behaviors in mice, probably by regulating Faecalibaculum_rodentium, carbohydrate enzymes and lipid metabolites.

Quercetin: A Promising Candidate for the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a chronic liver disease. The development of MASLD is influenced by a multitude of diseases associated with modern lifestyles, including but not limited to diabetes mellitus, hypertension, hyperlipidaemia and obesity. These conditions are often consequences of the adoption of unhealthy habits, namely a sedentary lifestyle, a lack of physical activity, poor dietary choices and excessive alcohol consumption. The treatment of MASLD is primarily based on modifying the patient's lifestyle and pharmacological intervention. Despite the absence of FDA-approved pharmacological agents for the treatment of MASLD, several potential therapeutic modalities have demonstrated efficacy in reversing the histopathological features of the disease. Among the botanical ingredients belonging to the flavonoid group is quercetin (QE). QE has been demonstrated to possess a number of beneficial physiological effects, including anti-inflammatory, anticancer and antifungal properties. Additionally, it functions as a natural antioxidant. Preclinical evidence indicates that QE may play a beneficial role in reducing liver damage and improving metabolic health. Early human studies also suggest that QE may be an effective treatment for MASLD due to its antioxidant, anti-inflammatory, and lipid-regulating properties. This review aims to summarize the available information on the therapeutic effects of QE in MASLD.

Type III Secretion System in Intestinal Pathogens and Metabolic Diseases

Modern lifestyle changes, especially the consumption of a diet high in salt, sugar, and fat, have contributed to the increasing incidence and prevalence of chronic metabolic diseases such as diabetes, obesity, and gout. Changing lifestyles continuously shape the gut microbiota which is closely related to the occurrence and development of metabolic diseases due to its specificity of composition and structural diversity. A large number of pathogenic bacteria such as Yersinia, Salmonella, Shigella, and pathogenic E. coli in the gut utilize the type III secretion system (T3SS) to help them resist host defenses and cause disease. Although the T3SS is critical for the virulence of many important human pathogens, its relationship with metabolic diseases remains unknown. This article reviews the structure and function of the T3SS, the disruption of intestinal barrier integrity by the T3SS, the changes in intestinal flora containing the T3SS in metabolic diseases, the possible mechanisms of the T3SS affecting metabolic diseases, and the application of the T3SS in the treatment of metabolic diseases. The aim is to provide insights into metabolic diseases targeting the T3SS, thereby serving as a valuable reference for future research on disease diagnosis, prevention, and treatment.

Characteristics of intestinal flora in nonobese nonalcoholic fatty liver disease patients and the impact of ursodeoxycholic acid treatment on these features

The study aimed to investigate the alterations in gut microbiota among nonobese individuals with nonalcoholic fatty liver disease (NAFLD) and their response to treatment with ursodeoxycholic acid (UDCA). A total of 90 patients diagnosed with NAFLD and 36 healthy subjects were recruited to participate in this study. Among them, a subgroup of 14 nonobese nonalcoholic steatohepatitis (NASH) were treated with UDCA. Demographic and serologic data were collected for all participants, while stool samples were obtained for fecal microbiome analysis using 16S sequencing. In nonobese NAFLD patients, the alpha diversity of intestinal flora decreased (Shannon index, p < 0.05), and the composition of intestinal flora changed (beta diversity, p < 0.05). The abundance of 20 genera, including Fusobacterium, Lachnoclostridium, Klebsiella, etc., exhibited significant changes (p < 0.05). Among them, nine species including Fusobacterium, Lachnoclostridium, Klebsiella, etc. were found to be associated with abnormal liver enzymes and glucolipid metabolic disorders. Among the 14 NASH patients treated with UDCA, improvements were observed in terms of liver enzymes, CAP values, and E values (p < 0.05), however, no improve the glucolipid metabolism. While the alpha diversity of intestinal flora did not show significant changes after UDCA treatment, there was a notable alteration in the composition of intestinal flora (beta diversity, p < 0.05). Furthermore, UCDA treatment led to an improvement in the relative abundance of Alistipes, Holdemanella, Gilisia, etc. among nonobese NASH patients (p < 0.05). Nonobese NAFLD patients exhibit dysbiosis of the intestinal microbiota. UDCA can ameliorate hepatic enzyme abnormalities and reduce liver fat content in nonobese NASH patients, potentially through its ability to restore intestinal microbiota balance.

Non-alcohlic Fatty Liver Disease (NAFLD): Is it a Dormant Volcano or Tip of an Iceberg?

Non-alcoholic fatty liver disease (NAFLD), a major cause of chronic liver disease, is known to affect a quarter of the global adults. Natural history of NAFLD shows interindividual variation, traditionally it progresses from simple steatosis to steatohepatitis to fibrosis/cirrhosis and finally yet rarely to hepatocellular carcinoma. It is largely a lifestyle-related disease and is often labeled as the hepatic manifestation of metabolic syndrome. Both prevention and control of NAFLD include controlling risk factors (obesity, diabetes mellitus, hypertension and dyslipidemia), through lifestyle modification and medications. Drug therapy for NAFLD per se is still evolving and till date, no drugs are approved. It is clinically silent, especially in the early stages, and is a diagnosis of exclusion. Certain easily calculated indices can stratify cases into high or low risk for advanced fibrosis, thereby dictating appropriate monitoring and treatment measures. In addition to complications specific to liver disease in those who do progress to advanced fibrosis or cirrhosis, an increased risk of nonliver disease-related morbidity and mortality is also present. Challenges are manifold and include rising burden due to ever-growing epidemic of diabetes and obesity, low public awareness, fragmented healthcare, no approved drugs, and dearth of data on magnitude and epidemiology of the disease. The recent integration of NAFLD into the National Program for Prevention and Control of Non-Communicable Diseases (NPCDCS) by the Ministry of Health and Family Welfare of India is a welcome step in this direction as the contributory factors are mostly the same for all diseases and controlling any one or all of them will have a desired impact on the prevalence of all the diseases under this program.

Impact of gut microbiota on metabolic dysfunction-associated steatohepatitis and hepatocellular carcinoma: pathways, diagnostic opportunities and therapeutic advances

Metabolic dysfunction-associated steatohepatitis (MASH) and progression to hepatocellular carcinoma (HCC) exhibits distinct molecular and immune characteristics. These traits are influenced by multiple factors, including the gut microbiome, which interacts with the liver through the "gut-liver axis". This bidirectional relationship between the gut and its microbiota and the liver plays a key role in driving various liver diseases, with microbial metabolites and immune responses being central to these processes. Our review consolidates the latest research on how gut microbiota contributes to MASH development and its progression to HCC, emphasizing new diagnostic and therapeutic possibilities. We performed a comprehensive literature review across PubMed/MedLine, Scopus, and Web of Science from January 2000 to August 2024, focusing on both preclinical and clinical studies that investigate the gut microbiota's roles in MASH and HCC. This includes research on pathogenesis, as well as diagnostic and therapeutic advancements related to the gut microbiota. This evidence emphasizes the critical role of the gut microbiome in the pathogenesis of MASH and HCC, highlighting the need for further clinical studies and trials. This is to refine diagnostic techniques and develop targeted therapies that exploit the microbiome's capabilities, aiming to enhance patient care in liver diseases.

Machine learning uncovers manganese as a key nutrient associated with reduced risk of steatotic liver disease

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects approximately 20%-30% of the general population and is linked to high-caloric western style diet. However, there are little data that specific nutrients might help to prevent steatosis.

METHODS

We analysed the UK Biobank (ID 71300) 24 h-nutritional assessments and investigated the association between nutrient intake calculated from food questionnaires and hepatic steatosis indicated by imaging or ICD10-coding. The effect of manganese (Mn) on subgroups with risk single nucleotide polymorphism carriage as well as the effect on metabolomics was investigated. All analyses are corrected for age, sex, body mass index, Townsend index for socioeconomic status, kcal, alcohol, protein intake, fat intake, carbohydrate intake, energy from beverages, diabetes, physical activity and for multiple testing.

RESULTS

We used a random forest classifier to analyse the feature importance of 63 nutrients and imaging-proven steatosis in a cohort of over 25 000 UK Biobank participants. Increased dietary Mn intake was associated with a lower likelihood of MRI-diagnosed steatosis. Subsequently, we conducted a cohort study in over 200 000 UK Biobank participants to explore the relationship between Mn intake and hepatic or cardiometabolic outcomes and found that higher Mn intake was associated with a lower risk of ICD-10 coded steatosis (OR = .889 [.838-.943], p < .001), independent of other potential confounders.

CONCLUSION

Our study provides evidence that higher Mn intake may be associated with lower odds of steatosis in a large population-based sample. These findings underline the potential role of Mn in the prevention of steatosis, but further research is needed to confirm these findings and to elucidate the underlying mechanisms.

Deciphering the Gut–Liver Axis: A Comprehensive Scientific Review of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has emerged as a significant global health issue. The condition is closely linked to metabolic dysfunctions such as obesity and type 2 diabetes. The gut–liver axis, a bidirectional communication pathway between the liver and the gut, plays a crucial role in the pathogenesis of NAFLD. This review delves into the mechanisms underlying the gut–liver axis, exploring the influence of gut microbiota, intestinal permeability, and inflammatory pathways. This review also explores the potential therapeutic strategies centered on modulating gut microbiota such as fecal microbiota transplantation; phage therapy; and the use of specific probiotics, prebiotics, and postbiotics in managing NAFLD. By understanding these interactions, we can better comprehend the development and advancement of NAFLD and identify potential therapeutic targets.

Gut-related molecules as potential biomarkers in patients with decompensated cirrhosis

INTRODUCTION AND OBJECTIVES

Microbial translocation contributes to cirrhosis progression and complications. This study aims to investigate whether molecules related to intestinal permeability or microbial translocation can serve as prognostic biomarkers in patients with decompensated cirrhosis.

MATERIALS AND METHODS

We prospectively evaluated hospitalized patients with decompensated cirrhosis for liver function, complications during hospitalization, in-hospital mortality, composite outcomes of in-hospital mortality and complications, 12-month mortality, and survival rates. Blood samples were collected upon admission, and 1,3 beta-d-glucan, zonulin, calprotectin, and lipopolysaccharide-binding protein were measured using commercial kits.

RESULTS

Ninety-one patients with decompensated cirrhosis were enrolled. The mean age was 58 ± 12 years; 57% were male. The three main cirrhosis etiologies were hepatitis C (35%), alcohol (25%), and non-alcoholic steatohepatitis (17%). In terms of liver function, 52% were Child C, and 68% had model for end-stage liver disease ≥15. The in-hospital and one-year mortality rates were 31% and 57%, respectively. Child-Pugh, 1,3 beta-glucan, and model for end-stage liver disease were positively correlated; zonulin was associated with complications during hospitalization (acute kidney injury) and composite outcomes, and calprotectin was associated with all outcomes except 12-month mortality.

CONCLUSIONS

Serum calprotectin and zonulin levels emerge as noninvasive prognostic biomarkers for potentially unfavorable outcomes in patients with decompensated cirrhosis.

Ginger essential oil prevents NASH progression by blocking the NLRP3 inflammasome and remodeling the gut microbiota-LPS-TLR4 pathway in mice

BACKGROUND

Diet and gut microbiota contribute to non-alcoholic steatohepatitis (NASH) progression. High-fat diets (HFDs) change gut microbiota compositions, induce gut dysbiosis, and intestinal barrier leakage, which facilitates portal influx of pathogen-associated molecular patterns including lipopolysaccharides (LPS) to the liver and triggers inflammation in NASH. Current therapeutic drugs for NASH have adverse side effects; however, several foods and herbs that exhibit hepatoprotection could be an alternative method to prevent NASH.

METHODS

We investigated ginger essential oil (GEO) against palm oil-containing HFDs in LPS-injected murine NASH model.

RESULTS

GEO reduced plasma alanine aminotransferase levels and hepatic pro-inflammatory cytokine levels; and increased antioxidant catalase, glutathione reductase, and glutathione levels to prevent NASH. GEO alleviated hepatic inflammation through mediated NLR family pyrin domain-containing 3 (NLRP3) inflammasome and LPS/Toll-like receptor four (TLR4) signaling pathways. GEO further increased beneficial bacterial abundance and reduced NASH-associated bacterial abundance.

CONCLUSION

This study demonstrated that GEO prevents NASH progression which is probably associated with the alterations of gut microbiota and inhibition of the LPS/TLR4/NF-κB pathway. Hence, GEO may offer a promising application as a dietary supplement for the prevention of NASH.

Hepatic Steatosis Can Be Partly Generated by the Gut Microbiota-Mitochondria Axis via 2-Oleoyl Glycerol and Reversed by a Combination of Soy Protein, Chia Oil, Curcumin and Nopal

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a serious health problem, and recent evidence indicates that gut microbiota plays a key role in its development. It is known that 2-oleoyl glycerol (2-OG) produced by the gut microbiota is associated with hepatic fibrosis, but it is not known whether this metabolite is involved in the development of hepatic steatosis. The aim of this study was to evaluate how a high-fat-sucrose diet (HFS) increases 2-OG production through gut microbiota dysbiosis and to identify whether this metabolite modifies hepatic lipogenesis and mitochondrial activity for the development of hepatic steatosis as well as whether a combination of functional foods can reverse this process. Wistar rats were fed the HFS diet for 7 months. At the end of the study, body composition, biochemical parameters, gut microbiota, protein abundance, lipogenic and antioxidant enzymes, hepatic 2-OG measurement, and mitochondrial function of the rats were evaluated. Also, the effect of the consumption of functional food with an HFS diet was assessed. In humans with MASLD, we analyzed gut microbiota and serum 2-OG. Consumption of the HFS diet in Wistar rats caused oxidative stress, hepatic steatosis, and gut microbiota dysbiosis, decreasing α-diversity and increased Blautia producta abundance, which increased 2-OG. This metabolite increased de novo lipogenesis through ChREBP and SREBP-1. 2-OG significantly increased mitochondrial dysfunction. The addition of functional foods to the diet modified the gut microbiota, reducing Blautia producta and 2-OG levels, leading to a decrease in body weight gain, body fat mass, serum glucose, insulin, cholesterol, triglycerides, fatty liver formation, and increased mitochondrial function. To use 2-OG as a biomarker, this metabolite was measured in healthy subjects or with MASLD, and it was observed that subjects with hepatic steatosis II and III had significantly higher 2-OG than healthy subjects, suggesting that the abundance of this circulating metabolite could be a predictor marker of hepatic steatosis.

Altered lipid metabolism and the development of metabolic-associated fatty liver disease

PURPOSE OF REVIEW

An increasing amount of research has underscored the significant role of lipoproteins in the pathogenesis of metabolic-associated fatty liver disease (MAFLD). This comprehensive review examines the intricate relationship between lipoprotein abnormalities and the development of MAFLD.

RECENT FINDINGS

Atherogenic dyslipidemia seen in insulin resistance states play a significant role in initiating and exacerbating hepatic lipid accumulation. There are also specific genetic factors ( PNPLA3 , TM6SF2 , MBOAT7 , HSD17B13 , GCKR- P446L) and transcription factors (SREBP-2, FXR, and LXR9) that increase susceptibility to both lipoprotein disorders and MAFLD. Most monogenic primary lipid disorders do not cause hepatic steatosis unless accompanied by metabolic stress. Hepatic steatosis occurs in the presence of secondary systemic metabolic stress in conjunction with predisposing environmental factors that lead to insulin resistance. Identifying specific aberrant lipoprotein metabolic factors promoting hepatic fat accumulation and subsequently exacerbating steatohepatitis will shed light on potential targets for therapeutic interventions.

SUMMARY

The clinical implications of interconnection between genetic factors and an insulin resistant environment that predisposes MAFLD is many fold. Potential therapeutic strategies in preventing or mitigating MAFLD progression include lifestyle modifications, pharmacological interventions, and emerging therapies targeting aberrant lipoprotein metabolism.

The role of gut microbiota augmentation in managing non-alcoholic fatty liver disease: an in-depth umbrella review of meta-analyses with grade assessment

Background and aim

Currently, there are no authorized medications specifically for non-alcoholic fatty liver disease (NAFLD) treatment. Studies indicate that changes in gut microbiota can disturb intestinal balance and impair the immune system and metabolism, thereby elevating the risk of developing and exacerbating NAFLD. Despite some debate, the potential benefits of microbial therapies in managing NAFLD have been shown.

Methods

A systematic search was undertaken to identify meta-analyses of randomized controlled trials that explored the effects of microbial therapy on the NAFLD population. The goal was to synthesize the existing evidence-based knowledge in this field.

Results

The results revealed that probiotics played a significant role in various aspects, including a reduction in liver stiffness (MD: -0.38, 95% CI: [-0.49, -0.26]), hepatic steatosis (OR: 4.87, 95% CI: [1.85, 12.79]), decrease in body mass index (MD: -1.46, 95% CI: [-2.43, -0.48]), diminished waist circumference (MD: -1.81, 95% CI: [-3.18, -0.43]), lowered alanine aminotransferase levels (MD: -13.40, 95% CI: [-17.02, -9.77]), decreased aspartate aminotransferase levels (MD: -13.54, 95% CI: [-17.85, -9.22]), lowered total cholesterol levels (MD: -15.38, 95% CI: [-26.49, -4.26]), decreased fasting plasma glucose levels (MD: -4.98, 95% CI: [-9.94, -0.01]), reduced fasting insulin (MD: -1.32, 95% CI: [-2.42, -0.21]), and a decline in homeostatic model assessment of insulin resistance (MD: -0.42, 95% CI: [-0.72, -0.11]) (P<0.05).

Conclusion

Overall, the results demonstrated that gut microbiota interventions could ameliorate a wide range of indicators including glycemic profile, dyslipidemia, anthropometric indices, and liver injury, allowing them to be considered a promising treatment strategy.

Gubra Amylin-NASH Diet Induced Nonalcoholic Fatty Liver Disease Associated with Histological Damage, Oxidative Stress, Immune Disorders, Gut Microbiota, and Its Metabolic Dysbiosis in Colon

SCOPE

The overall changes of colon under nonalcoholic fatty liver disease (NAFLD) remain to be further elucidated.

METHODS AND RESULTS

This study establishes a mouse model of NAFLD through a long-term Gubra Amylin-nonalcoholic steatohepatitis (NASH) diet (GAN diet). The results show that GAN diet significantly induces weight gain, liver steatosis, colonic oxidative stress, and lipid accumulation in blood, liver, and adipose tissue in mice. GAN feeding reduces the diversity of the gut microbiota, alters the composition and abundance of the gut microbiota, and leads to an increase in microbial metabolites such as long-chain fatty acids (LCFAs) and secondary bile acids (BAs), as well as a decrease in short-chain fatty acids (SCFAs). The RNA-seq and immunofluorescence results reveal that the GAN diet alters the expression of proteins and their coding genes involved in oxidative stress, immune response, and barrier function in colon tissue, such as lipocalin-2 (Lcn2, p < 0.05), heme oxygenase-1 (HO-1/Hmox1, p < 0.05), interferon-gamma (IFN-γ), and claudin-3/7. In addition, correlation analysis indicates a strong correlation between the changes in gut microbiota and lipid biomarkers. Additionally, the expression of immune related genes in colon tissue is related to the LCFAs produced by microbial metabolism.

CONCLUSION

GAN-induced NAFLD is related to microbiota and its metabolic imbalance, oxidative stress, immune disorders, and impaired barrier function in colon.

Effect of Supplementation of a Butyrate-Based Formula in Individuals with Liver Steatosis and Metabolic Syndrome: A Randomized Double-Blind Placebo-Controlled Clinical Trial

Postbiotics could exert different metabolic activities in animal models of non-alcoholic fatty liver disease (NAFLD) and in humans affected by metabolic syndrome. This is a randomized, double-blind, placebo-controlled, parallel-group clinical trial that enrolled a sample of 50 Caucasian healthy individuals with NAFLD, defined as liver steatosis, and metabolic syndrome. After a 4-week run-in, the enrolled individuals were randomized to take a food for special medical purposes with functional release, one tablet a day, containing calcium butyrate (500 mg/tablet), zinc gluconate (zinc 5 mg/tablet), and vitamin D3 (500 IU/tablet), or an identical placebo for 3 months. Liver and metabolic parameters were measured at baseline and at the end of the study. No subject experienced any adverse events during the trial. In both groups, a significant decrease in total cholesterol (TC) and triglycerides (TG) plasma levels was observed at the randomization visit vs. pre-run-in visit (p < 0.05). Regarding liver parameters, after treatment, the fatty liver index (FLI) improved significantly vs. baseline values (p < 0.05) and vs. placebo group (p < 0.05) in the active treatment group, and the hepatic steatosis index (HSI) improved significantly vs. baseline values (p < 0.05). Moreover, after active treatment, TC, TG, and gamma-glutamyl transferase (gGT) improved significantly vs. baseline values (p < 0.05), and TC and TG improved vs. placebo group (p < 0.05), as well. In the placebo group, liver parameters remained unchanged after treatment; only TG improved significantly vs. baseline values (p < 0.05). In our study, we observed that the butyrate-based formula improved FLI and plasma lipid patterns in individuals affected by liver steatosis and metabolic syndrome.

Global research trends on gut microbiota and metabolic dysfunction-associated steatohepatitis: Insights from bibliometric and scientometric analysis

Background

Metabolic dysfunction-associated steatohepatitis (MASH) is an inflammatory subtype of metabolic dysfunction-associated steatotic liver disease (MASLD) has recently been proposed as a replacement term for NAFLD, a common, multifactorial and poorly understood liver disease whose incidence is increasing worldwide. In recent years, there has been increasing scientific interest in exploring the relationship between gut microbiota and MASH. To learn more about the gut microbiota in MASH, this study aims to provide a comprehensive analysis of the knowledge structure and research hotspots from a bibliometric perspective.

Methods

We searched the Web of Science Core Collection for articles and reviews that covered the connections between gut microbiota and MASH over the last decade. The Online Analysis Platforms, VOSviewer, CiteSpace, the R tool "bibliometrix" were used to analyzed existing publications trends and hotspots.

Results

A total of 4,069 documents related to the interaction between gut microbiota and MASH were retrieved from 2014 to 2023. The number of annual publications increased significantly over the last decade, particularly in the United States and China. The University of California-San Diego was the most productive institution, while researcher Rohit Loomba published the most papers in the field. Younossi ZM was ranked as the first co-cited author and largest contributor of highly cited articles in the field. Gastroenterology and hepatology were the most common specialty category. The most cited journal in the last decade was Hepatology. The Keyword Bursts analysis highlighted the importance of studying the association between gut microbiota and MASH, as well as related factors such as metabolic syndrome, insulin resistance, endotoxemia and overgrowth of gut bacteria. Keyword clusters with co-citation were used to illustrate important topics including intestinal permeability, insulin sensitivity and liver immunology. The most common keywords include insulin resistance, obesity, dysbiosis, inflammation and oxidative stress, which are current hotspots.

Conclusion

Our analysis highlights key aspects of this field and emphasizes multiorgan crosstalk in MASLD/MASH pathogenesis. In particular, the central role of the gut-liver axis and the significant influence of gut microbiota dysbiosis on disease progression are highlighted. Furthermore, our results highlight the transformative potential of microbiota-specific therapies and cover the way for innovative healthcare and pharmaceutical strategies.

Gut microbial metabolites in MASLD: Implications of mitochondrial dysfunction in the pathogenesis and treatment

With an increasing prevalence, metabolic dysfunction-associated steatotic liver disease (MASLD) has become a major global health problem. MASLD is well-known as a multifactorial disease. Mitochondrial dysfunction and alterations in the gut bacteria are 2 vital events in MASLD. Recent studies have highlighted the cross-talk between microbiota and mitochondria, and mitochondria are recognized as pivotal targets of the gut microbiota to modulate the host's physiological state. Mitochondrial dysfunction plays a vital role in MASLD and is associated with multiple pathological changes, including hepatocyte steatosis, oxidative stress, inflammation, and fibrosis. Metabolites are crucial mediators of the gut microbiota that influence extraintestinal organs. Additionally, regulation of the composition of gut bacteria may serve as a promising therapeutic strategy for MASLD. This study reviewed the potential roles of several common metabolites in MASLD, emphasizing their impact on mitochondrial function. Finally, we discuss the current treatments for MASLD, including probiotics, prebiotics, antibiotics, and fecal microbiota transplantation. These methods concentrate on restoring the gut microbiota to promote host health.

Maternal obesity and metabolic (dysfunction) associated fatty liver disease in pregnancy: a comprehensive narrative review

INTRODUCTION

Obesity and metabolic-associated fatty liver disease (MAFLD) during pregnancy constitute significant problems for routine antenatal care, with increasing prevalence globally. Similar to obesity, MAFLD is associated with a higher risk for maternal complications (e.g. pre-eclampsia and gestational diabetes) and long-term adverse health outcomes for the offspring. However, MAFLD during pregnancy is often under-recognized, with limited management/treatment options.

AREAS COVERED

PubMed/MEDLINE, EMBASE, and Scopus were searched based on a search strategy for obesity and/or MAFLD in pregnancy to identify relevant papers up to 2024. This review summarizes the pertinent evidence on the relationship between maternal obesity and MAFLD during pregnancy. Key mechanisms implicated in the underlying pathophysiology linking obesity and MAFLD during pregnancy (e.g. insulin resistance and dysregulated adipokine secretion) are highlighted. Moreover, a diagnostic approach for MAFLD diagnosis during pregnancy and its complications are presented. Finally, promising relevant areas for future research are covered.

EXPERT OPINION

Research progress regarding maternal obesity, MAFLD, and their impact on maternal and fetal/offspring health is expected to improve the relevant diagnostic methods and lead to novel treatments. Thus, routine practice could apply more personalized management strategies, incorporating individualized algorithms with genetic and/or multi-biomarker profiling to guide prevention, early diagnosis, and treatment.

Potential of Chlorogenic Acid in the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Animal Studies and Clinical Trials-A Narrative Review

Chlorogenic acid (CGA) is a natural polyphenol found in coffee, tea, vegetables, and fruits. It exhibits strong antioxidant activity and possesses several other biological properties, including anti-inflammatory effects, antimicrobial activity, and insulin-sensitizing properties. Moreover, it may improve lipid and glucose metabolism. This review summarizes the available information on the therapeutic effect of CGA in metabolic dysfunction-associated steatotic liver disease (MASLD). As the literature search engine, the browsers in the PubMed, Scopus, Web of Science databases, and ClinicalTrials.gov register were used. Animal trials and clinical studies suggest that CGA has promising therapeutic potential in treating MASLD and hepatic steatosis. Its mechanisms of action include antioxidant, anti-inflammatory, and anti-apoptotic effects via the activation of the Nrf2 signaling pathway and the inhibition of the TLR4/NF-κB signaling cascade. Furthermore, the alleviation of liver disease by CGA also involves other important molecules such as AMPK and important physiological processes such as the intestinal barrier and gut microbiota. Nevertheless, the specific target cell and key molecule to which CGA is directed remain unidentified and require further study.

Low-Iron Diet-Induced Fatty Liver Development Is Microbiota Dependent and Exacerbated by Loss of the Mitochondrial Iron Importer Mitoferrin2

Iron deficiency is the number one nutritional problem worldwide. Iron uptake is regulated at the intestine and is highly influenced by the gut microbiome. Blood from the intestines drains directly into the liver, informing iron status and gut microbiota status. Changes in either iron or the microbiome are tightly correlated with the development of metabolic dysfunction-associated steatotic liver disease (MASLD). To investigate the underlying mechanisms of the development of MASLD that connect altered iron metabolism and gut microbiota, we compared specific pathogen free (SPF) or germ-free (GF) mice, fed a normal or low-iron diet. SPF mice on a low-iron diet showed reduced serum triglycerides and MASLD. In contrast, GF low-iron diet-fed mice showed increased serum triglycerides and did not develop hepatic steatosis. SPF mice showed significant changes in liver lipid metabolism and increased insulin resistance that was dependent upon the presence of the gut microbiota. We report that total body loss of mitochondrial iron importer Mitoferrin2 (Mfrn2-/-) exacerbated the development of MASLD on a low-iron diet with significant lipid metabolism alterations. Our study demonstrates a clear contribution of the gut microbiome, dietary iron, and Mfrn2 in the development of MASLD and metabolic syndrome.

Regulating bile acids signaling for NAFLD: molecular insights and novel therapeutic interventions

Nonalcoholic fatty liver disease (NAFLD) emerges as the most predominant cause of liver disease, tightly linked to metabolic dysfunction. Bile acids (BAs), initially synthesized from cholesterol in the liver, undergo further metabolism by gut bacteria. Increasingly acknowledged as critical modulators of metabolic processes, BAs have been implicated as important signaling molecules. In this review, we will focus on the mechanism of BAs signaling involved in glucose homeostasis, lipid metabolism, energy expenditure, and immune regulation and summarize their roles in the pathogenesis of NAFLD. Furthermore, gut microbiota dysbiosis plays a key role in the development of NAFLD, and the interactions between BAs and intestinal microbiota is elucidated. In addition, we also discuss potential therapeutic strategies for NAFLD, including drugs targeting BA receptors, modulation of intestinal microbiota, and metabolic surgery.

Role of pattern recognition receptors in the development of MASLD and potential therapeutic applications

Metabolic dysfunction-associated steatotic liver disease (MASLD) has become one of the most prevalent liver diseases worldwide, and its occurrence is strongly associated with obesity, insulin resistance (IR), genetics, and metabolic stress. Ranging from simple fatty liver to metabolic dysfunction-associated steatohepatitis (MASH), even to severe complications such as liver fibrosis and advanced cirrhosis or hepatocellular carcinoma, the underlying mechanisms of MASLD progression are complex and involve multiple cellular mediators and related signaling pathways. Pattern recognition receptors (PRRs) from the innate immune system, including Toll-like receptors (TLRs), C-type lectin receptors (CLRs), NOD-like receptors (NLRs), RIG-like receptors (RLRs), and DNA receptors, have been demonstrated to potentially contribute to the pathogenesis for MASLD. Their signaling pathways can induce inflammation, mediate oxidative stress, and affect the gut microbiota balance, ultimately resulting in hepatic steatosis, inflammatory injury and fibrosis. Here we review the available literature regarding the involvement of PRR-associated signals in the pathogenic and clinical features of MASLD, in vitro and in animal models of MASLD. We also discuss the emerging targets from PRRs for drug developments that involved agent therapies intended to arrest or reverse disease progression, thus enabling the refinement of therapeutic targets that can accelerate drug development.