The links between the gut microbiome and non-alcoholic fatty liver disease (NAFLD)

Role of gut-liver axis and glucagon-like peptide-1 receptor agonists in the treatment of metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a hepatic manifestation of the metabolic syndrome. It is one of the most common liver diseases worldwide and shows increasing prevalence rates in most countries. MAFLD is a progressive disease with the most severe cases presenting as advanced fibrosis or cirrhosis with an increased risk of hepatocellular carcinoma. Gut microbiota play a significant role in the pathogenesis and progression of MAFLD by disrupting the gut-liver axis. The mechanisms involved in maintaining gut-liver axis homeostasis are complex. One critical aspect involves preserving an appropriate intestinal barrier permeability and levels of intestinal lumen metabolites to ensure gut-liver axis functionality. An increase in intestinal barrier permeability induces metabolic endotoxemia that leads to steatohepatitis. Moreover, alterations in the absorption of various metabolites can affect liver metabolism and induce liver steatosis and fibrosis. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are a class of drugs developed for the treatment of type 2 diabetes mellitus. They are also commonly used to combat obesity and have been proven to be effective in reversing hepatic steatosis. The mechanisms reported to be involved in this effect include an improved regulation of glycemia, reduced lipid synthesis, β-oxidation of free fatty acids, and induction of autophagy in hepatic cells. Recently, multiple peptide receptor agonists have been introduced and are expected to increase the effectiveness of the treatment. A modulation of gut microbiota has also been observed with the use of these drugs that may contribute to the amelioration of MAFLD. This review presents the current understanding of the role of the gut-liver axis in the development of MAFLD and use of members of the GLP-1 RA family as pleiotropic agents in the treatment of MAFLD.

Lipidomic Analysis Reveals Alterations in Hepatic FA Profile Associated With MASLD Stage in Patients With Obesity

CONTEXT

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by the intracellular lipid accumulation in hepatocytes. Excess caloric intake and high-fat diets are considered to significantly contribute to MASLD development.

OBJECTIVE

To evaluate the hepatic and serum fatty acid (FA) composition in patients with different stages of MASLD, and their relationship with FA dietary intake and MASLD-related risk factors.

METHODS

This was a case-control study in patients with obesity undergoing bariatric surgery at a university hospital between January 2020 and December 2021. Participants were distributed in 3 groups: no MASLD (n = 26), steatotic liver disease (n = 33), and metabolic dysfunction-associated steatohepatitis (n = 32). Hepatic and serum FA levels were determined by gas chromatography-mass spectrometry. Nutritional status was evaluated using validated food frequency questionnaires. The hepatic expression of genes involved in FA metabolism was analyzed by reverse transcription quantitative polymerase chain reaction.

RESULTS

The hepatic, but not serum, FA profiles were significantly altered in patients with MASLD compared with those without MASLD. No differences were observed in FA intake between the groups. Levels of C16:0, C18:1, and the C18:1/C18:0 ratio were higher, while C18:0 levels and C18:0/C16:0 ratio were lower in patients with MASLD, being significantly different between the 3 groups. Hepatic FA levels and ratios correlated with histopathological diagnosis and other MASLD-related parameters. The expression of genes involved in the FA metabolism was upregulated in patients with MASLD.

CONCLUSION

Alterations in hepatic FA levels in MASLD patients were due to enhancement of de novo lipogenesis in the liver.

Cu exposure induces liver inflammation via regulating gut microbiota/LPS/liver TLR4 signaling axis

Copper (Cu) serves as an essential cofactor in all organisms, yet excessive Cu exposure is widely recognized for its role in inducing liver inflammation. However, the precise mechanism by which Cu triggers liver inflammation in ducks, particularly in relation to the interplay in gut microbiota regulation, has remained elusive. In this investigation, we sought to elucidate the impact of Cu exposure on liver inflammation through gut-liver axis in ducks. Our findings revealed that Cu exposure markedly elevated liver AST and ALT levels and induced liver inflammation through upregulating pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and triggering the LPS/TLR4/NF-κB signaling pathway. Simultaneously, Cu exposure induced alterations in the composition of intestinal flora communities, notably increasing the relative abundance of Sphingobacterium, Campylobacter, Acinetobacter and reducing the relative abundance of Lactobacillus. Cu exposure significantly decreased the protein expression related to intestinal barrier (Occludin, Claudin-1 and ZO-1) and promoted the secretion of intestinal pro-inflammatory cytokines. Furthermore, correlation analysis was observed that intestinal microbiome and gut barrier induced by Cu were closely related to liver inflammation. Fecal microbiota transplantation (FMT) experiments further demonstrated the microbiota-depleted ducks transplanting fecal samples from Cu-exposed ducks disturbed the intestinal dysfunction, which lead to impaire liver function and activate the liver inflammation. Our study provided insights into the mechanism by which Cu exposure induced liver inflammation in ducks through the regulation of gut-liver axis. These results enhanced our comprehension of the potential mechanisms driving Cu-induced hepatotoxicity in avian species.

Gut-liver axis: Potential mechanisms of action of food-derived extracellular vesicles

Food-derived extracellular vesicles (FEVs) are nanoscale membrane vesicles obtained from dietary materials such as breast milk, plants and probiotics. Distinct from other EVs, FEVs can survive the harsh degrading conditions in the gastrointestinal tract and reach the intestines. This unique feature allows FEVs to be promising prebiotics in health and oral nanomedicine for gut disorders, such as inflammatory bowel disease. Interestingly, therapeutic effects of FEVs have recently also been observed in non-gastrointestinal diseases. However, the mechanisms remain unclear or even mysterious. It is speculated that orally administered FEVs could enter the bloodstream, reach remote organs, and thus exert therapeutic effects therein. However, emerging evidence suggests that the amount of FEVs reaching organs beyond the gastrointestinal tract is marginal and may be insufficient to account for the significant therapeutic effects achieved regarding diseases involving remote organs such as the liver. Thus, we herein propose that FEVs primarily act locally in the intestine by modulating intestinal microenvironments such as barrier integrity and microbiota, thereby eliciting therapeutic impact remotely on the liver in non-gastrointestinal diseases via the gut-liver axis. Likewise, drugs delivered to the gastrointestinal system through FEVs may act via the gut-liver axis. As the liver is the main metabolic hub, the intestinal microenvironment may be implicated in other metabolic diseases. In fact, many patients with non-alcoholic fatty liver disease, obesity, diabetes and cardiovascular disease suffer from a leaky gut and dysbiosis. In this review, we provide an overview of the recent progress in FEVs and discuss their biomedical applications as therapeutic agents and drug delivery systems, highlighting the pivotal role of the gut-liver axis in the mechanisms of action of FEVs for the treatment of gut disorders and metabolic diseases.

Semaglutide alters gut microbiota and improves NAFLD in db/db mice

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease associated with type 2 diabetes mellitus (T2D). NAFLD can progress to nonalcoholic steatohepatitis (NASH), cirrhosis, and even cancer, all of which have a very poor prognosis. Semaglutide, a novel glucagon-like peptide-1 (GLP-1) receptor agonist, has been recognized as a specific drug for the treatment of diabetes. In this study, we used a gene mutation mouse model (db/db mice) to investigate the potential liver-improving effects of semaglutide. The results showed that semaglutide improved lipid levels and glucose metabolism in db/db mice. HE staining and oil red staining showed alleviation of liver damage and reduction of hepatic lipid deposition after injection of semaglutide. In addition, semaglutide also improved the integrity of gut barrier and altered gut microbiota, especially Alloprevotella, Alistpes, Ligilactobacillus and Lactobacillus. In summary, our findings validate that semaglutide induces modifications in the composition of the gut microbiota and ameliorates NAFLD, positioning it as a promising therapeutic candidate for addressing hepatic steatosis and associated inflammation.

Sheng-Jiang powder ameliorates NAFLD via regulating intestinal microbiota in mice

Background

Intestinal microbiota have been demonstrated to be involved in the development of NAFLD, while the relationship between the severity of NAFLD and intestinal microbiota is still not fully elucidated. Sheng-Jiang Powder (SJP) showed exact efficacy in treating SFL and great potential in regulating intestinal microbiota, but the effects need to be further addressed in NASH and liver fibrosis.

Objectives

To investigate the differences in intestinal microbiota of NAFLD with different severity and the effect of SJP on liver damage and intestinal microbiota.

Design

NAFLD mice models with different severity were induced by high-fat diet (HFD) or choline-deficient, L-amino acid-defined high-fat diet (CDAHFD) feeding and then treated with SJP/normal saline.

Methods

Biochemical blood tests, H&E/Masson/Oil Red O/IHC staining, Western blot, and 16SrDNA sequencing were performed to explore intestinal microbiota alteration in different NAFLD models and the effect of SJP on liver damage and intestinal microbiota.

Results

Intestinal microbiota alteration was detected in all NAFLD mice. SJP induced increased expression of Pparγ and alleviated liver lipid deposition in all NAFLD mice. Microbiome analysis revealed obvious changes in intestinal microbiota composition, while SJP significantly elevated the relative abundance of Roseburia and Akkermansia, which were demonstrated to be beneficial for improving inflammation and intestinal barrier function.

Conclusion

Our results demonstrated that SJP was effective in improving lipid metabolism in NAFLD mice, especially in mice with SFL. The potential mechanism may be associated with the regulation of intestinal microbiota.

The impact of gut microbiome-targeted therapy on liver enzymes in patients with nonalcoholic fatty liver disease: an umbrella meta-analysis

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is considered the leading cause of chronic liver disease worldwide. To date, no confirmed medication is available for the treatment of NAFLD. Previous studies showed the promising effects of gut microbiome-targeted therapies; however, the results were controversial and the strength of the evidence and their clinical significance remained unclear.

OBJECTIVES

This umbrella study summarizes the results of meta-analyses investigating the effects of probiotics, prebiotics, and synbiotics on liver enzymes in the NAFLD population.

DATA SOURCE

A comprehensive search of the PubMed, Scopus, Web of Science, and Cochrane Library databases was done up to December 20, 2022, to find meta-analyses on randomized control trials reporting the effects of gut microbial therapy on patients with NAFLD.

DATA EXTRACTION

Two independent investigators extracted data on the characteristics of meta-analyses, and any discrepancies were resolved by a third researcher. The AMSTAR2 checklist was used for evaluating the quality of studies.

DATA ANALYSIS

A final total of 15 studies were included in the analysis. Results showed that microbiome-targeted therapies could significantly reduce levels of alanine aminotransferase (ALT; effect size [ES], -10.21; 95% confidence interval [CI], -13.29, -7.14; P < 0.001), aspartate aminotransferase (AST; ES, -8.86; 95%CI, -11.39, -6.32; P < 0.001), and γ-glutamyltransferase (ES, -5.56; 95%CI, -7.92, -3.31; P < 0.001) in patients with NAFLD. Results of subgroup analysis based on intervention showed probiotics could significantly reduce levels of AST (ES, -8.69; 95%CI, -11.01, -6.37; P < 0.001) and ALT (ES, -9.82; 95%CI, -11.59, -8.05; P < 0.001). Synbiotics could significantly reduce levels of AST (ES, -11.40; 95%CI, -13.91, -8.88; P < 0.001) and ALT (ES, -11.87; 95%CI, -13.80, -9.95; P < 0.001). Prebiotics had no significant effects on AST and ALT levels (ES, -2.96; 95%CI, -8.12, 2.18, P = 0.259; and ES, -4.69; 95%CI, -13.53, 4.15, P = 0.299, respectively).

CONCLUSION

Gut microbiome-targeted therapies could be a promising therapeutic approach in the improvement of hepatic damage in patients with NAFLD. However, more studies are needed to better determine the best bacterial strains, duration of treatment, and optimum dosage of gut microbiome-targeted therapies in the treatment of the NAFLD population.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022346998.

Lactobacillus paracasei subsp. paracasei 2004 improves health and lifespan in Caenorhabditis elegans

Recent research has highlighted the importance of the gut microbiome in regulating aging, and probiotics are interventions that can promote gut health. In this study, we surveyed several novel lactic acid bacteria to examine their beneficial effect on organismal health and lifespan in C. elegans. We found that animals fed some lactic acid bacteria, including L. acidophilus 1244 and L. paracasei subsp. paracasei 2004, grew healthy. Supplementation with the lactic acid bacterial strains L. acidophilus 1244 or L. paracasei subsp. paracasei 2004 significantly improved health, including food consumption, motility, and resistance to oxidative stressor, hydrogen peroxide. Our RNA-seq analysis showed that supplementation with L. paracasei subsp. paracasei 2004 significantly increased the expression of daf-16, a C. elegans FoxO homolog, as well as genes related to the stress response. Furthermore, daf-16 deletion inhibited the longevity effect of L. paracasei subsp. paracasei 2004 supplementation. Our results suggest that L. paracasei subsp. paracasei 2004 improves health and lifespan in a DAF-16-dependent manner.

Genome engineering of the human gut microbiome

The human gut microbiome, a complex ecosystem, significantly influences host health, impacting crucial aspects such as metabolism and immunity. To enhance our comprehension and control of the molecular mechanisms orchestrating the intricate interplay between gut commensal bacteria and human health, the exploration of genome engineering for gut microbes is a promising frontier. Nevertheless, the complexities and diversities inherent in the gut microbiome pose substantial challenges to the development of effective genome engineering tools for human gut microbes. In this comprehensive review, we provide an overview of the current progress and challenges in genome engineering of human gut commensal bacteria, whether executed in vitro or in situ. A specific focus is directed towards the advancements and prospects in cargo DNA delivery and high-throughput techniques. Additionally, we elucidate the immense potential of genome engineering methods to enhance our understanding of the human gut microbiome and engineer the microorganisms to enhance human health.

Diagnostic performance of the GGT/HDL-C ratio for NAFLD in adults with obesity undergoing bariatric surgery

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become the most frequent liver disease, closely related with metabolic risk factors such as obesity, insulin resistance, dyslipidemia, diabetes mellitus, and metabolic syndrome. In this context, γ-Glutamyl transpeptidase (GGT) and high-density lipoprotein cholesterol (HDL-C) have shown correlations with steatosis severity and metabolic syndrome, respectively. This positions the GGT/HDL-C ratio as a potential diagnostic indicator for NAFLD.

OBJECTIVE

To assess the diagnostic performance of the GGT/HDL-C ratio for NAFLD in adults with obesity undergoing bariatric surgery.

METHODS

We conducted an analytical cross-sectional study, designed as a diagnostic test evaluation. A secondary database of 249 adults with obesity was analyzed. The optimal cut-off point was ascertained using three methodologies, and five adjustment models were constructed for the total population, further stratified by sex.

RESULTS

The optimal cut-off point was 20.5 U/mmol and the AUC of the ratio was 0.81 (95% CI: 0.64-0.98), with sensitivity and specificity being 82.5% and 77.8%, respectively. In the overall group with an elevated GGT/HDL-C ratio, the prevalence of NAFLD increased by 14% (PR: 1.14; 95% CI: 1.04-1.33). Specifically, women displaying this altered ratio showed a 19% increased prevalence (PR: 1.19; 95% CI: 1.07-1.42) compared to those with normal values.

CONCLUSIONS

The GGT/HDL-C ratio is a promising biomarker for the diagnosis of NAFLD in an adult population living with obesity.

Smilax China L. polysaccharide prevents HFD induced-NAFLD by regulating hepatic fat metabolism and gut microbiota

BACKGROUND

The increasing incidence of nonalcoholic fatty liver disease (NAFLD) has urged the development of new therapeutics. NAFLD is intimately linked to gut microbiota due to the hepatic portal system, and utilizing natural polysaccharides as prebiotics has become a prospective strategy for preventing NAFLD. Smilax china L. polysaccharide (SCP) possesses excellent hepatoprotective and anti-inflammatory activity. However, its protective effects on NAFLD remains unclear.

PURPOSE

The goal of this study was to explore the protective effects of SCP on high-fat diet (HFD)-induced NAFLD mice by regulating hepatic fat metabolism and gut microbiota.

METHODS

Extraction and isolation from Smilax china L. rhizome to obtain SCP. C57BL/6 J mice were distributed to six groups: Control (normal chow diet), HFD-fed mice were assigned to HFD, simvastatin (SVT), and low-, medium-, high-doses of SCP for 12 weeks. The body, liver, and different adipose tissues weights were detected, and lipids in serum and liver were assessed. RT-PCR and Western blot were used to detect the hepatic fat metabolism-related genes and proteins. Gut microbiota of cecum contents was profiled through 16S rRNA gene sequencing.

RESULTS

SCP effectively reversed HFD-induced increase weights of body, liver, and different adipose tissues. Lipid levels of serum and liver were also significantly reduced after SCP intervention. According to the results of RT-PCR and western blot analysis, SCP treatment up-regulated the genes and proteins related to lipolysis were up-regulated, while lipogenesis-related genes and proteins were down-regulated. Furthermore, the HFD-induced dysbiosis of intestinal microbiota was similarly repaired by SCP intervention, including enriching beneficial bacteria and depleting harmful bacteria.

CONCLUSION

SCP could effectively prevent HFD-induced NAFLD, might be considered as a prebiotic agent due to its excellent effects on altering hepatic fat metabolism and maintaining gut microbiota homeostasis.

Effect of circadian rhythm change on gut microbiota and the development of nonalcoholic fatty liver disease in mice

BACKGROUND

This study was to investigate the effect and possible mechanism of circadian rhythm change on the development of nonalcoholic fatty liver disease (NAFLD) in mice.

METHODS

A total of 80 male SPF-grade 4-week C57BL/6J mice were randomly divided into normal diet normal light/dark cycle (ND-LD) and high-fat diet all dark (HFD-DD) groups. Weight measurements were taken weekly, and after 24 weeks of intervention, 24 mice from both groups were randomly selected and analyzed. Additionally, the remaining mice in the HFD-DD group were divided into two groups: one group continued the high-fat all-dark treatment (HFD-DD-DD), and the other group was restored to normal light/dark cycle treatment (HFD-DD-LD). Mice were euthanized after a total of 48 weeks of intervention. Measurements were taken for each mouse including liver function serum indicators, liver tissue pathological sections, rhythm-related proteins, and determination of the gut microbiota community.

RESULTS

The HFD induced NAFLD in mice, exhibiting symptoms such as obesity, lipid and glucose metabolism disorders, elevated liver enzymes, and decreased gut microbiota diversity. The composition of the gut microbiota was significantly different from that of the normal diet group, with a significant increase in the ratio of Firmicutes to Bacteroides. Restoration of normal light/dark cycles exacerbated the disorder of lipid metabolism, liver steatosis, and the expression of BMAL1 in mice and significantly reduced the diversity of gut microbiota.

CONCLUSIONS

Circadian rhythm changes aggravate the development of NAFLD induced by a high-fat diet by affecting glucose metabolism, liver steatosis, and gut microbiota diversity. Restoration of normal circadian rhythm did not improve NAFLD. Our findings open up new avenues for the prevention, diagnosis, and treatment of NAFLD.

Vitamin D and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Novel Mechanistic Insights

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an increasingly prevalent condition characterized by abnormal fat accumulation in the liver, often associated with metabolic disorders. Emerging evidence suggests a potential link between vitamin D deficiency and the development and progression of MASLD. The current review provides a concise overview of recent studies uncovering novel mechanistic insights into the interplay between vitamin D and MASLD. Several epidemiological studies have highlighted a significant association between low vitamin D levels and an increased risk of MASLD. Vitamin D, traditionally known for its role in bone health, has now been recognized as a key player in various physiological processes, including immune regulation and inflammation. Experimental studies using animal models have demonstrated that vitamin D deficiency exacerbates liver steatosis and inflammation, suggesting a potential protective role against MASLD. Mechanistically, vitamin D appears to modulate MASLD through multiple pathways. Firstly, the vitamin D receptor (VDR) is abundantly expressed in liver cells, indicating a direct regulatory role in hepatic function. Activation of the VDR has been shown to suppress hepatic lipid accumulation and inflammation, providing a mechanistic basis for the observed protective effects. Additionally, vitamin D influences insulin sensitivity, a critical factor in MASLD pathogenesis. Improved insulin sensitivity may mitigate the excessive accumulation of fat in the liver, thus attenuating MASLD progression. In parallel, vitamin D exhibits anti-inflammatory properties by inhibiting pro-inflammatory cytokines implicated in MASLD pathophysiology. Experimental evidence suggests that the immunomodulatory effects of vitamin D extend to the liver, reducing inflammation and oxidative stress, key drivers of MASLD, and the likelihood of hepatocyte injury and fibrosis. Understanding the complex interplay between vitamin D and MASLD provides a basis for exploring targeted therapeutic strategies and preventive interventions. As vitamin D deficiency is a modifiable risk factor, addressing this nutritional concern may prove beneficial in mitigating the burden of MASLD and associated metabolic disorders.

Impact of Synbiotic Intake on Liver Metabolism in Metabolically Healthy Participants and Its Potential Preventive Effect on Metabolic-Dysfunction-Associated Fatty Liver Disease (MAFLD): A Randomized, Placebo-Controlled, Double-Blinded Clinical Trial

Synbiotics modulate the gut microbiome and contribute to the prevention of liver diseases such as metabolic-dysfunction-associated fatty liver disease (MAFLD). This study aimed to evaluate the effect of a randomized, placebo-controlled, double-blinded seven-week intervention trial on the liver metabolism in 117 metabolically healthy male participants. Anthropometric data, blood parameters, and stool samples were analyzed using linear mixed models. After seven weeks of intervention, there was a significant reduction in alanine aminotransferase (ALT) in the synbiotic group compared to the placebo group (-14.92%, CI: -26.60--3.23%, p = 0.013). A stratified analysis according to body fat percentage revealed a significant decrease in ALT (-20.70%, CI: -40.88--0.53%, p = 0.045) in participants with an elevated body fat percentage. Further, a significant change in microbiome composition (1.16, CI: 0.06-2.25, p = 0.039) in this group was found, while the microbial composition remained stable upon intervention in the group with physiological body fat. The 7-week synbiotic intervention reduced ALT levels, especially in participants with an elevated body fat percentage, possibly due to modulation of the gut microbiome. Synbiotic intake may be helpful in delaying the progression of MAFLD and could be used in addition to the recommended lifestyle modification therapy.

Shenling Baizhu San ameliorates non-alcoholic fatty liver disease in mice by modulating gut microbiota and metabolites

Purpose: The prevalence of non-alcoholic fatty liver disease (NAFLD) and its related mortality is increasing at an unprecedented rate. Traditional Chinese medicine (TCM) has been shown to offer potential for early prevention and treatment of NAFLD. The new mechanism of "Shenling Baizhu San" (SLBZS) is examined in this study for the prevention and treatment of NAFLD at the preclinical level. Methods: Male C57BL/6J mice were randomly divided into three groups: normal diet (ND), western diet + CCl4 injection (WDC), and SLBZS intervention (WDC + SLBZS). Body weights, energy intake, liver enzymes, pro-inflammatory factors, and steatosis were recorded in detail. Meanwhile, TPH1, 5-HT, HTR2A, and HTR2B were tested using qRT-PCR or ELISA. Dynamic changes in the gut microbiota and metabolites were further detected through the 16S rRNA gene and untargeted metabolomics. Results: SLBZS intervention for 6 weeks could reduce the serum and liver lipid profiles, glucose, and pro-inflammatory factors while improving insulin resistance and liver function indexes in the mice, thus alleviating NAFLD in mice. More importantly, significant changes were found in the intestinal TPH-1, 5-HT, liver 5-HT, and related receptors HTR2A and HTR2B. The 16S rRNA gene analysis suggested that SLBZS was able to modulate the disturbance of gut microbiota, remarkably increasing the relative abundance of probiotics (Bifidobacterium and Parvibacter) and inhibiting the growth of pro-inflammatory bacteria (Erysipelatoclostridium and Lachnoclostridium) in mice with NAFLD. Combined with metabolomics in positive- and negative-ion-mode analyses, approximately 50 common differential metabolites were selected via non-targeted metabolomics detection, which indicated that the targeting effect of SLBZS included lipid metabolites, bile acids (BAs), amino acids (AAs), and tryptophan metabolites. In particular, the lipid metabolites 15-OxEDE, vitamin D3, desoxycortone, and oleoyl ethanol amide were restored by SLBZS. Conclusion: Integrating the above results of multiple omics suggests that SLBZS ameliorates NAFLD via specific gut microbiota, gut-derived 5-HT, and related metabolites to decrease fat accumulation in the liver and inflammatory responses.

Novel insights into macrophage immunometabolism in nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH), an inflammatory subtype of nonalcoholic fatty liver disease (NAFLD), is characterized by liver steatosis, inflammation, hepatocellular injury and different degrees of fibrosis, and has been becoming the leading cause of liver-related morbidity and mortality worldwide. Unfortunately, the pathogenesis of NASH has not been completely clarified, and there are no approved therapeutic drugs. Recent accumulated evidences have revealed the involvement of macrophage in the regulation of host liver steatosis, inflammation and fibrosis, and different phenotypes of macrophages have different metabolic characteristics. Therefore, targeted regulation of macrophage immunometabolism may contribute to the treatment and prognosis of NASH. In this review, we summarized the current evidences of the role of macrophage immunometabolism in NASH, especially focused on the related function conversion, as well as the strategies to promote its polarization balance in the liver, and hold promise for macrophage immunometabolism-targeted therapies in the treatment of NASH.

Unlocking the Therapeutic Potential of Ellagic Acid for Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Obesity is in epidemic proportions in many parts of the world, contributing to increasing rates of non-alcoholic fatty liver disease (NAFLD). NAFLD represents a range of conditions from the initial stage of fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to severe fibrosis, through to hepatocellular carcinoma. There currently exists no treatment for the long-term management of NAFLD/NASH, however, dietary interventions have been investigated for the treatment of NASH, including several polyphenolic compounds. Ellagic acid is one such polyphenolic compound. Nutraceutical food abundant in ellagic acid undergoes initial hydrolysis to free ellagic acid within the stomach and small intestine. The proposed mechanism of action of ellagic acid extends beyond its initial therapeutic potential, as it is further broken down by the gut microbiome into urolithin. Both ellagic acid and urolithin have been found to alleviate oxidative stress, inflammation, and fibrosis, which are associated with NAFLD/NASH. While progress has been made in understanding the pharmacological and biological activity of ellagic acid and its involvement in NAFLD/NASH, it has yet to be fully elucidated. Thus, the aim of this review is to summarise the currently available literature elucidating the therapeutic potential of ellagic acid and its microbial-derived metabolite urolithin in NAFLD/NASH.

Gut Microbiome-How Does Two-Month Consumption of Fiber-Enriched Rolls Change Microbiome in Patients Suffering from MASLD?

BACKGROUND

The occurrence of metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing global problem which commonly affects patients with co-existing diseases/conditions, such as type 2 diabetes and dyslipidemia. The effective treatment of MASLD is still limited; however, diet plays a significant role in its management. There are multiple beneficial properties of dietary fiber, including its ability to modify the gut microbiome. Therefore, the aim of this study was to determine the effect of the consumption of fiber-enriched rolls on the gut microbiome and microbial metabolites in patients suffering from MASLD.

METHODS

The participants were recruited according to the inclusion criteria and were required to consume fiber-enriched rolls containing either 6 g or 12 g of fiber. There were three assessment timepoints, when the anthropometric and laboratory parameters were measured, and 16s on nanopore sequencing of the fecal microbiome was conducted.

RESULTS

Firmicutes and Bacteroidetes were the most abundant phyla in the patients living with MASLD. It was demonstrated that the amount of short-chain fatty acids (SCFAs) changed after the consumption of fiber-enriched rolls; however, this was strongly associated with both the timepoint and the type of SCFAs-acetate and butyrate. Additionally, the high-fiber diet was related to the increase in phyla diversity (p = 0.006571).

CONCLUSIONS

Overall, the introduction of an appropriate amount of fiber to the diet seems to be promising for patients suffering from MASLD due to its ability to create an improvement in gut microbiome-related aspects.

Supplementation of Silymarin Alone or in Combination with Salvianolic Acids B and Puerarin Regulates Gut Microbiota and Its Metabolism to Improve High-Fat Diet-Induced NAFLD in Mice

Silymarin, salvianolic acids B, and puerarin were considered healthy food agents with tremendous potential to ameliorate non-alcoholic fatty liver disease (NAFLD). However, the mechanisms by which they interact with gut microbiota to exert benefits are largely unknown. After 8 weeks of NAFLD modeling, C57BL/6J mice were randomly divided into five groups and fed a normal diet, high-fat diet (HFD), or HFD supplemented with a medium or high dose of Silybum marianum extract contained silymarin or polyherbal extract contained silymarin, salvianolic acids B, and puerarin for 16 weeks, respectively. The untargeted metabolomics and 16S rRNA sequencing were used for molecular mechanisms exploration. The intervention of silymarin and polyherbal extract significantly improved liver steatosis and recovered liver function in the mice, accompanied by an increase in probiotics like Akkermansia and Blautia, and suppressed Clostridium, which related to changes in the bile acids profile in feces and serum. Fecal microbiome transplantation confirmed that this alteration of microbiota and its metabolites were responsible for the improvement in NAFLD. The present study substantiated that alterations of the gut microbiota upon silymarin and polyherbal extract intervention have beneficial effects on HFD-induced hepatic steatosis and suggested the pivotal role of gut microbiota and its metabolites in the amelioration of NAFLD.

Intestinal Barrier Dysfunction and Gut Microbiota in Non-Alcoholic Fatty Liver Disease: Assessment, Mechanisms, and Therapeutic Considerations

Non-alcoholic fatty liver disease (NAFLD) is a type of metabolic stress liver injury closely related to insulin resistance (IR) and genetic susceptibility without alcohol consumption, which encompasses a spectrum of liver disorders ranging from simple hepatic lipid accumulation, known as steatosis, to the more severe form of steatohepatitis (NASH). NASH can progress to cirrhosis and hepatocellular carcinoma (HCC), posing significant health risks. As a multisystem disease, NAFLD is closely associated with systemic insulin resistance, central obesity, and metabolic disorders, which contribute to its pathogenesis and the development of extrahepatic complications, such as cardiovascular disease (CVD), type 2 diabetes mellitus, chronic kidney disease, and certain extrahepatic cancers. Recent evidence highlights the indispensable roles of intestinal barrier dysfunction and gut microbiota in the onset and progression of NAFLD/NASH. This review provides a comprehensive insight into the role of intestinal barrier dysfunction and gut microbiota in NAFLD, including intestinal barrier function and assessment, inflammatory factors, TLR4 signaling, and the gut-liver axis. Finally, we conclude with a discussion on the potential therapeutic strategies targeting gut permeability and gut microbiota in individuals with NAFLD/NASH, such as interventions with medications/probiotics, fecal transplantation (FMT), and modifications in lifestyle, including exercise and diet.

Probiotic yogurt regulates gut microbiota homeostasis and alleviates hepatic steatosis and liver injury induced by high-fat diet in golden hamsters

This study aimed to investigate the beneficial effects of probiotic yogurt on lipid metabolism and gut microbiota in metabolic-related fatty liver disease (MAFLD) golden hamsters fed on a high-fat diet (HFD). The results demonstrated that probiotic yogurt significantly reversed the adverse effects caused by HFD, such as body and liver weight gain, liver steatosis and damage, sterol deposition, and oxidative stress after 8 weeks of intervention. qRT-PCR analysis showed that golden hamsters fed HFD had upregulated genes related to adipogenesis, increased free fatty acid infiltration, and downregulated genes related to lipolysis and very low-density lipoprotein secretion. Probiotic yogurt supplements significantly inhibited HFD-induced changes in the expression of lipid metabolism-related genes. Furthermore, 16S rRNA gene sequencing of the intestinal content microbiota suggested that probiotic yogurt changed the diversity and composition of the gut microbiota in HFD-fed hamsters. Probiotic yogurt decreased the ratio of the phyla Firmicutes/Bacteroidetes, the relative abundance of the LPS-producing genus Desulfovibrio, and bacteria involved in lipid metabolism, whereas it increased the relative abundance of short-chain fatty acids producing bacteria in HFD-fed hamsters. Predictive functional analysis of the microbial community showed that probiotic yogurt-modified genes involved in LPS biosynthesis and lipid metabolism. In summary, these findings support the possibility that probiotic yogurt significantly improves HFD-induced metabolic disorders through modulating intestinal microflora and lipid metabolism and effectively regulating the occurrence and development of MAFLD. Therefore, probiotic yogurt supplementation may serve as an effective nutrition strategy for the treatment of patients with MAFLD clinically.

The causal effect of mTORC1-dependent circulating protein levels on nonalcoholic fatty liver disease: A Mendelian randomization study

BACKGROUND

The mechanistic target of rapamycin (mTOR) signal pathway plays a crucial role in the development of nonalcoholic fatty liver disease (NAFLD). However, the causal effect of mTOR downstream proteins on NAFLD remains unknown.

AIMS

We conducted a two-sample Mendelian randomization (MR) study to investigate whether the mTOR-dependent circulating proteins, including Eukaryotic Initiation Factor 4E Binding Proteins (eIF4EBPs), Ribosomal Protein S6K kinase 1 (RP-S6K), Eukaryotic Initiation Factor 4E (eIF4E), Eukaryotic Initiation Factor 4A (eIF4A) and Eukaryotic Initiation Factor 4 G (eIF4G), have causal effects on the risk of NAFLD.

METHODS

The causal estimate was evaluated with the inverse-variance weighted (IVW) method in discovery stage and validation stage. The single-nucleotide polymorphisms (SNPs) were selected to genetically predict exposures from Genome-Wide Association Studies (GWAS). Exposures with statistically significant effects in the discovery dataset would be further validated in the validation dataset.

RESULTS

MR study revealed that eIF4E had a causal effect on NAFLD in both discovery stage (OR = 1.339, P = 0.037) and validation stage (OR = 1.0007, P = 0.022). Sensitivity analyses confirmed robustness of the results.

CONCLUSION

The genetically predicted higher level of mTOR-dependent eIF4E in plasma might have a causal effect on the occurrence of NAFLD.

A revisit of drugs and potential therapeutic targets against non-alcoholic fatty liver disease: learning from clinical trials

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease, with a worldwide prevalence of 25%. Although numerous clinical trials have been conducted over the last few decades, an effective treatment has not been approved yet. Extensive research has accumulated a large amount of data and experience; however, the vast number of clinical trials and new therapeutic targets for NAFLD make it impossible to keep abreast of the relevant information. Therefore, a systematic analysis of the existing trials is necessary.

METHODS

Here, we reviewed clinical trials on NAFLD registered in the mandated federal database, ClinicalTrials.gov, to generate a detailed overview of the trials related to drugs and therapeutic targets for NAFLD treatment. Following screening for pertinence to therapy, a total of 440 entries were identified that included active trials as well as those that have already been completed, suspended, terminated, or withdrawn.

RESULTS

We summarize and systematically analyze the state, drug development pipeline, and discovery of treatment targets for NAFLD. We consider possible factors that may affect clinical outcomes. Furthermore, we discussed these results to explore the mechanisms responsible for clinical outcomes.

CONCLUSION

We summarised the landscape of current clinical trials and suggested the directions for future NAFLD therapy to assist internal medicine specialists in treating the whole clinical spectrum of this highly prevalent liver disease.

Polyphenols synergistic drugs to ameliorate non-alcoholic fatty liver disease via signal pathway and gut microbiota: A review

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease with an increasing incidence worldwide. Single drug therapy may have toxic side effects and disrupt gut microbiota balance. Polyphenols are widely used in disease intervention due to their distinctive nutritional properties and medicinal value, which a potential gut microbiota modulator. However, there is a lack of comprehensive review to explore the efficacy and mechanism of combined therapy with drugs and polyphenols for NAFLD.

AIM OF REVIEW

Based on this, this review firstly discusses the link between NAFLD and gut microbiota, and outlines the effects of polyphenols and drugs on gut microbiota. Secondly, it examined recent advances in the treatment and intervention of NAFLD with drugs and polyphenols and the therapeutic effect of the combination of the two. Finally, we highlight the underlying mechanisms of polyphenol combined drug therapy in NAFLD. This is mainly in terms of signaling pathways (NF-κB, AMPK, Nrf2, JAK/STAT, PPAR, SREBP-1c, PI3K/Akt and TLR) and gut microbiota. Furthermore, some emerging mechanisms such as microRNA potential biomarker therapies may provide therapeutic avenues for NAFLD.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Drawing inspiration from combination drug strategies, the use of active substances in combination with drugs for NAFLD intervention holds transformative and prospective potential, both improve NAFLD and restore gut microbiota balance while reducing the required drug dosage. This review systematically discusses the bidirectional interactions between gut microbiota and NAFLD, and summarizes the potential mechanisms of polyphenol synergistic drugs in the treatment of NAFLD by modulating signaling pathways and gut microbiota. Future researches should develop multi-omics technology to identify patients who benefit from polyphenols combination drugs and devising individualized treatment plans to enhance its therapeutic effect.

Dual-Stimuli-Responsive Gut Microbiota-Targeting Nitidine Chloride-CS/PT-NPs Improved Metabolic Status in NAFLD

Background and Purpose

Nitidine chloride (NC) is a botanical drug renowned for its potent anti-inflammatory, antimalarial, and hepatocellular carcinoma-inhibiting properties; however, its limited solubility poses challenges to its development and application. To address this issue, we have devised a colon-targeted delivery system (NC-CS/PT-NPs) aimed at modulating the dysbiosis of the gut microbiota by augmenting the interaction between NC and the intestinal microbiota, thereby exerting an effect against nonalcoholic fatty liver disease.

Methods

The NC-CS/PT-NPs were synthesized using the ion gel method. Subsequently, the particle size distribution, morphology, drug loading efficiency, and release behavior of the NC-CS/PT-NPs were characterized. Furthermore, the impact of NC-CS/PT-NPs on non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet (HFD) in mice was investigated through serum biochemical analysis, ELISA, and histochemical staining. Additionally, the influence of NC-CS/PT-NPs on intestinal microbiota was analyzed using 16S rDNA gene sequencing.

Results

The nanoparticles prepared in this study have an average particle size of (255.9±5.10) nm, with an encapsulation rate of (72.83±2.13) % and a drug loading of (4.65±0.44) %. In vitro release experiments demonstrated that the cumulative release rate in the stomach and small intestine was lower than 22.0%, while it reached 66.75% in the colon. In vivo experiments conducted on HFD-induced NAFLD mice showed that treatment with NC-CS/PT-NPs inhibited weight gain, decreased serum aspartate aminotransferase (AST), Alanine aminotransferase (ALT) and lipid levels, improved liver and intestinal inflammation, and altered the diversity of gut microbiota in mice.

Conclusion

This study provides new evidence for the treatment of NAFLD through the regulation of gut microbiota using active ingredients from traditional Chinese medicine.

Gut microbiome features and metabolites in non-alcoholic fatty liver disease among community-dwelling middle-aged and older adults

BACKGROUND

The specific microbiota and associated metabolites linked to non-alcoholic fatty liver disease (NAFLD) are still controversial. Thus, we aimed to understand how the core gut microbiota and metabolites impact NAFLD.

METHODS

The data for the discovery cohort were collected from the Guangzhou Nutrition and Health Study (GNHS) follow-up conducted between 2014 and 2018. We collected 272 metadata points from 1546 individuals. The metadata were input into four interpretable machine learning models to identify important gut microbiota associated with NAFLD. These models were subsequently applied to two validation cohorts [the internal validation cohort (n = 377), and the prospective validation cohort (n = 749)] to assess generalizability. We constructed an individual microbiome risk score (MRS) based on the identified gut microbiota and conducted animal faecal microbiome transplantation experiment using faecal samples from individuals with different levels of MRS to determine the relationship between MRS and NAFLD. Additionally, we conducted targeted metabolomic sequencing of faecal samples to analyse potential metabolites.

RESULTS

Among the four machine learning models used, the lightGBM algorithm achieved the best performance. A total of 12 taxa-related features of the microbiota were selected by the lightGBM algorithm and further used to calculate the MRS. Increased MRS was positively associated with the presence of NAFLD, with odds ratio (OR) of 1.86 (1.72, 2.02) per 1-unit increase in MRS. An elevated abundance of the faecal microbiota (f__veillonellaceae) was associated with increased NAFLD risk, whereas f__rikenellaceae, f__barnesiellaceae, and s__adolescentis were associated with a decreased presence of NAFLD. Higher levels of specific gut microbiota-derived metabolites of bile acids (taurocholic acid) might be positively associated with both a higher MRS and NAFLD risk. FMT in mice further confirmed a causal association between a higher MRS and the development of NAFLD.

CONCLUSIONS

We confirmed that an alteration in the composition of the core gut microbiota might be biologically relevant to NAFLD development. Our work demonstrated the role of the microbiota in the development of NAFLD.

The synbiotic combination of probiotics and inulin improves NAFLD though modulating gut microbiota

Prebiotics can promote the growth of probiotics, cocombine of these is called synbiotics, and synbiotics is powerful regulators of gut microbiota. Intestinal microbiota plays an important role in nonalcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. This study aims to investigate the effect of synbiotics combination of probiotics (Streptococcus Bifidobacterium and Streptococcus thermophilus) and prebiotics (Inulin) in vivo model of early NAFLD using yogurt as carrier. The results demonstrate that the yogurt with synbiotics combination group (HS) improves the biochemical indicators related to total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and insulin resistance (IR) in mice (P< .01). HS improves the development of lipid metabolism and inflammation by activating the AMPK and NFκB signaling pathway. In addition, HS restores the intestinal barrier dysfunction and inflammation caused by a high-fat diet. The 16S rRNA demonstrates that the gut microbiota composition of mice treated with HS is significantly altered specifically, the Firmicutes/Bacteroidetes ratio is significantly lower than in HFD-fed mice (P< .01). Our findings suggest the applicability of HS in preventing obesity-related NAFLD via its antioxidant, anti-inflammatory, and improved lipid metabolism by the gut-liver axis and provide a solid theoretical foundation for developing prebiotics for the prevention of NAFLD.

Effects of plant natural products on metabolic-associated fatty liver disease and the underlying mechanisms: a narrative review with a focus on the modulation of the gut microbiota

Metabolic-associated fatty liver disease (MAFLD) is a chronic liver disease characterized by the excessive accumulation of fat in hepatocytes. However, due to the complex pathogenesis of MAFLD, there are no officially approved drugs for treatment. Therefore, there is an urgent need to find safe and effective anti-MAFLD drugs. Recently, the relationship between the gut microbiota and MAFLD has been widely recognized, and treating MAFLD by regulating the gut microbiota may be a new therapeutic strategy. Natural products, especially plant natural products, have attracted much attention in the treatment of MAFLD due to their multiple targets and pathways and few side effects. Moreover, the structure and function of the gut microbiota can be influenced by exposure to plant natural products. However, the effects of plant natural products on MAFLD through targeting of the gut microbiota and the underlying mechanisms are poorly understood. Based on the above information and to address the potential therapeutic role of plant natural products in MAFLD, we systematically summarize the effects and mechanisms of action of plant natural products in the prevention and treatment of MAFLD through targeting of the gut microbiota. This narrative review provides feasible ideas for further exploration of safer and more effective natural drugs for the prevention and treatment of MAFLD.

Pilot Study: Safety and Performance Validation of an Ingestible Medical Device for Collecting Small Intestinal Liquid in Healthy Volunteers

The connection between imbalances in the human gut microbiota, known as dysbiosis, and various diseases has been well established. Current techniques for sampling the small intestine are both invasive for patients and costly for healthcare facilities. Most studies on human gut microbiome are conducted using faecal samples, which do not accurately represent the microbiome in the upper intestinal tract. A pilot clinical investigation, registered as NCT05477069 and sponsored by the Grenoble Alpes University Hospital, is currently underway to evaluate a novel ingestible medical device (MD) designed for collecting small intestinal liquids by Pelican Health. This study is interventional and monocentric, involving 15 healthy volunteers. The primary objective of the study is to establish the safety and the performance of the MD when used on healthy volunteers. Secondary objectives include assessing the device's performance and demonstrating the difference between the retrieved sample from the MD and the corresponding faecal sample. Multi-omics analysis will be performed, including metagenomics, metabolomics, and culturomics. We anticipate that the MD will prove to be safe without any reported adverse effects, and we collected samples suitable for the proposed omics analyses in order to demonstrate the functionality of the MD and the clinical potential of the intestinal content.

Metabolic Insights into Caffeine's Anti-Adipogenic Effects: An Exploration through Intestinal Microbiota Modulation in Obesity

Obesity, a chronic condition marked by the excessive accumulation of adipose tissue, not only affects individual well-being but also significantly inflates healthcare costs. The physiological excess of fat manifests as triglyceride (TG) deposition within adipose tissue, with white adipose tissue (WAT) expansion via adipocyte hyperplasia being a key adipogenesis mechanism. As efforts intensify to address this global health crisis, understanding the complex interplay of contributing factors becomes critical for effective public health interventions and improved patient outcomes. In this context, gut microbiota-derived metabolites play an important role in orchestrating obesity modulation. Microbial lipopolysaccharides (LPS), secondary bile acids (BA), short-chain fatty acids (SCFAs), and trimethylamine (TMA) are the main intestinal metabolites in dyslipidemic states. Emerging evidence highlights the microbiota's substantial role in influencing host metabolism and subsequent health outcomes, presenting new avenues for therapeutic strategies, including polyphenol-based manipulations of these microbial populations. Among various agents, caffeine emerges as a potent modulator of metabolic pathways, exhibiting anti-inflammatory, antioxidant, and obesity-mitigating properties. Notably, caffeine's anti-adipogenic potential, attributed to the downregulation of key adipogenesis regulators, has been established. Recent findings further indicate that caffeine's influence on obesity may be mediated through alterations in the gut microbiota and its metabolic byproducts. Therefore, the present review summarizes the anti-adipogenic effect of caffeine in modulating obesity through the intestinal microbiota and its metabolites.

Quantitative proteomics study of carnosine effect in an animal model of Western diet-induced nonalcoholic fatty liver disease

The nonalcoholic fatty liver disease (NAFLD), which is closely related to westernized dietary (WD) patterns, displays a rising epidemiological and economic burden. Since there is no pharmacological therapy approved for this disease, mechanistic studies are warranted. In this work, we investigated the action of carnosine (CAR), a natural dipeptide with several protection roles against oxidative stress in the liver of NAFLD rats. NAFLD was induced by WD-rich sugars and fat, verifying the histological evidence of steatosis. As intraperitoneal administration of CAR reversed liver steatosis, the protein profiles of NAFLD liver and CAR NAFLD liver were evaluated by label-free proteomics approach. A total of 2531 proteins were identified and the 230 and 276 were significantly up- and downregulated, respectively, by CAR treatment of NAFLD rats and involved in fundamental pathways such as oxidative stress and lipid metabolism. Perilipin 2 and apolipoprotein E, components of the plasma membrane of vesicle, resulted in highly downregulated in the CAR-treated NAFLD liver. The advanced bioanalytical approach demonstrated the efficacy of CAR in overcoming the main symptoms of NAFLD, ameliorating the steatosis in the liver.

Dietary bile acids supplementation improves the growth performance and alleviates fatty liver in broilers fed a high-fat diet via improving the gut microbiota

This experiment aims to evaluate the effect of bile acids (BAs) in alleviating fatty liver disease induced by a high-fat diet (HFD) in broilers, and the modulation of the gut microbiota involved in this process. A total of 192 one-day-old Arbor Acres (AA) commercial male broilers were randomly divided into 4 groups and treated with the following diet: a basal-fat diet (BFD), a basal-fat diet plus bile acids (BFD + BAs), an HFD, and a high-fat diet plus bile acids (HFD + BAs). Bile acids were supplemented at the early growth stage (3-7 d), middle stage (17-21 d), and late stage (31-35 d). Results showed that BAs treatment had a significant effect on body weight on 14 d and 35 d, and increased the breast muscle weight and its index, but decreased the liver weight and abdominal fat weight on 35 d (P < 0.05). The supplementation of BAs significantly improved the serum lipid profile and decreased the level of triglycerides (TG), total cholesterol (TCHO), and nonesterified fatty acids (NEFA) on 35 d (P < 0.05). Dietary BAs supplementation significantly alleviated the hepatic TG deposition induced by HFD (P < 0.05), which was accompanied by upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and lipoprotein lipase (LPL) gene expression (P < 0.05). Moreover, the expression levels of hepatic gene adipose triglyceride lipase (ATGL), peroxisome proliferator-activated receptor α (PPARα), and apolipoprotein B (APOB) were greatly increased by BAs treatment. The analysis of 16S rRNA sequencing showed that the microbial diversity of the cecal digesta was increased by BAs in broilers with elevated abundances of Firmicutes, Lactobacillus, Anaerostipes, Sellimonas, and CHKCI002 and decreased abundances of Barnesiella and Akkermansia genus (P < 0.05). Hepatic TG content was positively correlated with the abundance of Oscillospiraceae, but it was negatively correlated with the abundance of Lactobacillus in cecal digesta (P < 0.05). These results indicate that dietary BAs can improve growth performance and alleviate fatty liver disease induced by an HFD via modulating gut microbiota in broilers.

Gut Microbiota Plays Essential Roles in Soyasaponin's Preventive Bioactivities against Steatohepatitis in the Methionine and Choline Deficient (MCD) Diet-Induced Non-Alcoholic Steatohepatitis (NASH) Mice

SCOPE

Gut microbiota (GM) is involved in nonalcoholic steatohepatitis (NASH) development. Phytochemicals soyasaponins can prevent NASH possibly by modulating GM. This study aims to investigate the preventive bioactivities of soyasaponin monomers (SS-A1 and SS-Bb) against NASH and explores the mechanisms by targeting GM.

METHODS AND RESULTS

Male C57BL/6 mice are fed with methionine and choline deficient (MCD) diet containing SS-A1 , SS-Bb, or not for 16 weeks. Antibiotics-treated pseudo germ-free (PGF) mice are fed with MCD diet containing SS-A1 , SS-Bb, or not for 8 weeks. GM is determined by 16S rRNA amplicon sequencing. Bile acids (BAs) are measured by UPLC-MS/MS. In NASH mice, SS-A1 and SS-Bb alleviate steatohepatitis and fibrosis, reduce ALT, AST, and LPS in serum, decrease TNF-α, IL-6, α-SMA, triglycerides, and cholesterol in liver. SS-A1 and SS-Bb decrease Firmicutes, Erysipelotrichaceae, unidentified-Clostridiales, Eggerthellaceae, Atopobiaceae, Aerococcus, Jeotgalicoccus, Gemella, Rikenella, increase Proteobacteria, Verrucomicrobia, Akkermansiaceae, Romboutsia, and Roseburia. SS-A1 and SS-Bb alter BAs composition in liver, serum, and feces, activate farnesoid X receptor (FXR) in liver and ileum, increase occludin and ZO-1 in intestine. However, GM clearance abrogates the preventive bioactivities of SS-A1 and SS-Bb against NASH.

CONCLUSION

GM plays essential roles in soyasaponin's preventive bioactivities against steatohepatitis in MCD diet-induced NASH mice.

Immunomodulation in non-alcoholic fatty liver disease: exploring mechanisms and applications

Non-alcoholic fatty liver disease (NAFLD) exhibits increased lipid enrichment in hepatocytes. The spectrum of this disease includes stages such as nonalcoholic simple fatty liver (NAFL), nonalcoholic steatohepatitis (NASH), and liver fibrosis. Changes in lifestyle behaviors have been a major factor contributing to the increased cases of NAFLD patients globally. Therefore, it is imperative to explore the pathogenesis of NAFLD, identify therapeutic targets, and develop new strategies to improve the clinical management of the disease. Immunoregulation is a strategy through which the organism recognizes and eliminates antigenic foreign bodies to maintain physiological homeostasis. In this process, multiple factors, including immune cells, signaling molecules, and cytokines, play a role in governing the evolution of NAFLD. This review seeks to encapsulate the advancements in research regarding immune regulation in NAFLD, spanning from underlying mechanisms to practical applications.

Liver cirrhosis and complications from the perspective of dysbiosis

The gut-liver axis refers to the intimate relationship and rigorous interaction between the gut and the liver. The intestinal barrier's integrity is critical for maintaining liver homeostasis. The liver operates as a second firewall in this interaction, limiting the movement of potentially dangerous compounds from the gut and, as a result, contributing in barrier management. An increasing amount of evidence shows that increased intestinal permeability and subsequent bacterial translocation play a role in liver damage development. The major pathogenic causes in cirrhotic individuals include poor intestinal permeability, nutrition, and intestinal flora dysbiosis. Portal hypertension promotes intestinal permeability and bacterial translocation in advanced liver disease, increasing liver damage. Bacterial dysbiosis is closely related to the development of cirrhosis and its related complications. This article describes the potential mechanisms of dysbiosis in liver cirrhosis and related complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma, using dysbiosis of the intestinal flora as an entry point.

Zanthoxylum bungeanum amides ameliorates nonalcoholic fatty liver via regulating gut microbiota and activating AMPK/Nrf2 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Zanthoxylum bungeanum Maxim. (Rutaceae) is a known herbal medicine with various bioactivities, including anti-obesity, lipid-lowering, learning & memory improving and anti-diabetes, and amides in Z. bungeanum (AZB) are considered as the major active agents for its bioactivities.

AIM OF THE STUDY

This research was carried out to uncover the anti-NAFL effect of AZB and its corresponding molecular mechanisms.

METHODS

The central composite design-response surface methodology (CCD-RSM) was utilized to optimize the AZB extraction process, and the anti-NAFL effect of AZB was investigated on high fat diet (HFD) fed mice (HFD mice). The levels of ROS in liver tissues were determined using laser confocal microscopy with DCFH-DA probe staining, and anti-enzymes (such as HO-1, SOD, CAT & GSH-PX) and MDA in liver tissues were measured using commercial detecting kits. GC-MS was used to determine the short-chain fatty acids (SCFAs) contents in feces and blood of mice. 16S high-throughput sequencing, western blotting (WB) assay and immunofluorescence (IF) were used to explore the intestinal flora changes in mice and the potential mechanisms of AZB for treatment of NAFL.

RESULTS

Our results showed AZB reduced body weight, alleviated liver pathological changes, reduced fat accumulation, and improved oxidative stress in HFD mice. In addition, we also found AZB improved OGTT and ITT, reduced TG, TC, LDL-C, whereas increased HDL-C in HFD mice. AZB increased total number of the species and interspecies kinship of gut microbiota and reduced the richness and diversity of gut microbiota in HFD mice. Moreover, AZB decreased the ratio of Firmicutes/Bacteroidota, whereas increased the abundance of Allobaculum, Bacteroides and Dubosiella in feces of HFD-fed mice. Furthermore, AZB increased the production of SCFAs, and up-regulated the phosphorylation of AMPK and increased the nuclear transcription of Nrf2 in liver of HFD mice.

CONCLUSION

Collectively, our results suggested AZB can improve NAFL, which could reduce body weight, reverse liver lesions and fat accumulation, improve oxidative stress in liver tissues of HFD mice. Furthermore, the mechanisms are related to increase of the abundance of high-producing bacteria for SCFAs (e.g. Allobaculum, Bacteroides and Dubosiella) to activate AMPK/Nrf2 signaling.

Gut microbiota and metabolic modulation by supplementation of polysaccharide-producing Bacillus licheniformis from Tibetan Yaks: A comprehensive multi-omics analysis

Gut microbiota and their metabolic processes depend on the intricate interplay of gut microbiota and their metabolic processes. Bacillus licheniformis, a beneficial food supplement, has shown promising effects on stabilizing gut microbiota and metabolites. However, the precise mechanisms underlying these effects remain elusive. In this study, we investigated the impact of polysaccharide-producing B. licheniformis as a dietary supplement on the gut microbiome and metabolites through a combination of scanning electron microscopy (SEM), histological analysis, high-throughput sequencing (HTS), and metabolomics. Our findings revealed that the B. licheniformis-treated group exhibited significantly increased jejunal goblet cells. Moreover, gut microbial diversity was lower in the treatment group as compared to the control, accompanied by noteworthy shifts in the abundance of specific bacterial taxa. Enrichment of Firmicutes, Lachnospiraceae, and Clostridiales_bacterium contrasted with reduced levels of Campylobacterota, Proteobacteria, Parasutterella, and Helicobacter. Notably, the treatment group showed significant weight gain after 33 days, emphasizing the polysaccharide's impact on host metabolism. Delving into gut metabolomics, we discovered significant alterations in metabolites. Nine metabolites, including olprinone, pyruvic acid, and 2-methyl-3-oxopropanoate, were upregulated, while eleven, including defoslimod and voclosporin were down-regulated, shedding light on phenylpropanoid biosynthesis, tricarboxylic acid cycle (TCA cycle), and the glucagon signaling pathway. This comprehensive multi-omics analysis offers compelling insights into the potential of B. licheniformis as a dietary polysaccharide supplement for gut health and host metabolism, promising significant implications for gut-related issues.

Gut microbiota-derived indole compounds attenuate metabolic dysfunction-associated steatotic liver disease by improving fat metabolism and inflammation

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease, and its prevalence has increased worldwide in recent years. Additionally, there is a close relationship between MASLD and gut microbiota-derived metabolites. However, the mechanisms of MASLD and its metabolites are still unclear. We demonstrated decreased indole-3-propionic acid (IPA) and indole-3-acetic acid (IAA) in the feces of patients with hepatic steatosis compared to healthy controls. Here, IPA and IAA administration ameliorated hepatic steatosis and inflammation in an animal model of WD-induced MASLD by suppressing the NF-κB signaling pathway through a reduction in endotoxin levels and inactivation of macrophages. Bifidobacterium bifidum metabolizes tryptophan to produce IAA, and B. bifidum effectively prevents hepatic steatosis and inflammation through the production of IAA. Our study demonstrates that IPA and IAA derived from the gut microbiota have novel preventive or therapeutic potential for MASLD treatment.

GLP-1/GLP-1RAs: New Options for the Drug Treatment of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has recently emerged as a global public health concern. Currently, the cornerstone of NAFLD treatment is lifestyle modification and, if necessary, weight loss. However, compliance is a challenge, and this approach alone may not be sufficient to halt and treat the more serious disease development, so medication is urgently needed. Nevertheless, no medicines are approved to treat NAFLD. Glucagon-like peptide-1 (GLP-1) is an enteropeptide hormone that inhibits glucagon synthesis, promotes insulin secretion, and delays gastric emptying. GLP-1 has been found in recent studies to be beneficial for the management of NAFLD, and the marketed GLP-1 agonist drugs have different degrees of effectiveness for NAFLD while lowering blood glucose. In this article, we review GLP-1 and its physiological roles, the pathogenesis of NAFLD, the correlation between NAFLD and GLP-1 signaling, and potential strategies for GLP-1 treatment of NAFLD.

Nutraceutical Properties of Syringic Acid in Civilization Diseases-Review

Civilization diseases account for a worldwide health issue. They result from daily behavioral, environmental, and genetic factors. One of the most significant opportunities to prevent and alleviate the occurrence of these diseases is a diet rich in antioxidants like polyphenols. This review paper is concentrated on syringic acid (SA), one of the representative compounds of phenolic acids subgroups. There are many in vitro and in vivo studies on SA that assess its pivotal effects on oxidative stress and inflammation parameters. It is effective on metabolic risk factors as well, including hyperglycemia, high blood pressure, and hyperlipidemia. SA is one of the prominent polyphenolic compounds that may help address health issues related to civilization diseases.

Exploring a novel therapeutic strategy: the interplay between gut microbiota and high-fat diet in the pathogenesis of metabolic disorders

In the past two decades, the rapid increase in the incidence of metabolic diseases, including obesity, diabetes, dyslipidemia, non-alcoholic fatty liver disease, hypertension, and hyperuricemia, has been attributed to high-fat diets (HFD) and decreased physical activity levels. Although the phenotypes and pathologies of these metabolic diseases vary, patients with these diseases exhibit disease-specific alterations in the composition and function of their gut microbiota. Studies in germ-free mice have shown that both HFD and gut microbiota can promote the development of metabolic diseases, and HFD can disrupt the balance of gut microbiota. Therefore, investigating the interaction between gut microbiota and HFD in the pathogenesis of metabolic diseases is crucial for identifying novel therapeutic strategies for these diseases. This review takes HFD as the starting point, providing a detailed analysis of the pivotal role of HFD in the development of metabolic disorders. It comprehensively elucidates the impact of HFD on the balance of intestinal microbiota, analyzes the mechanisms underlying gut microbiota dysbiosis leading to metabolic disruptions, and explores the associated genetic factors. Finally, the potential of targeting the gut microbiota as a means to address metabolic disturbances induced by HFD is discussed. In summary, this review offers theoretical support and proposes new research avenues for investigating the role of nutrition-related factors in the pathogenesis of metabolic disorders in the organism.

Chronic jet lag alters gut microbiome and mycobiome and promotes the progression of MAFLD in HFHFD-fed mice

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide. Circadian disruptors, such as chronic jet lag (CJ), may be new risk factors for MAFLD development. However, the roles of CJ on MAFLD are insufficiently understood, with mechanisms remaining elusive. Studies suggest a link between gut microbiome dysbiosis and MAFLD, but most of the studies are mainly focused on gut bacteria, ignoring other components of gut microbes, such as gut fungi (mycobiome), and few studies have addressed the rhythm of the gut fungi. This study explored the effects of CJ on MAFLD and its related microbiotic and mycobiotic mechanisms in mice fed a high fat and high fructose diet (HFHFD). Forty-eight C57BL6J male mice were divided into four groups: mice on a normal diet exposed to a normal circadian cycle (ND-NC), mice on a normal diet subjected to CJ (ND-CJ), mice on a HFHFD exposed to a normal circadian cycle (HFHFD-NC), and mice on a HFHFD subjected to CJ (HFHFD-CJ). After 16 weeks, the composition and rhythm of microbiota and mycobiome in colon contents were compared among groups. The results showed that CJ exacerbated hepatic steatohepatitis in the HFHFD-fed mice. Compared with HFHFD-NC mice, HFHFD-CJ mice had increases in Aspergillus, Blumeria and lower abundances of Akkermansia, Lactococcus, Prevotella, Clostridium, Bifidobacterium, Wickerhamomyces, and Saccharomycopsis genera. The fungi-bacterial interaction network became more complex after HFHFD and/or CJ interventions. The study revealed that CJ altered the composition and structure of the gut bacteria and fungi, disrupted the rhythmic oscillation of the gut microbiota and mycobiome, affected interactions among the gut microbiome, and promoted the progression of MAFLD in HFHFD mice.

Gut liver brain axis in diseases: the implications for therapeutic interventions

Gut-liver-brain axis is a three-way highway of information interaction system among the gastrointestinal tract, liver, and nervous systems. In the past few decades, breakthrough progress has been made in the gut liver brain axis, mainly through understanding its formation mechanism and increasing treatment strategies. In this review, we discuss various complex networks including barrier permeability, gut hormones, gut microbial metabolites, vagus nerve, neurotransmitters, immunity, brain toxic metabolites, β-amyloid (Aβ) metabolism, and epigenetic regulation in the gut-liver-brain axis. Some therapies containing antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), polyphenols, low FODMAP diet and nanotechnology application regulate the gut liver brain axis. Besides, some special treatments targeting gut-liver axis include farnesoid X receptor (FXR) agonists, takeda G protein-coupled receptor 5 (TGR5) agonists, glucagon-like peptide-1 (GLP-1) receptor antagonists and fibroblast growth factor 19 (FGF19) analogs. Targeting gut-brain axis embraces cognitive behavioral therapy (CBT), antidepressants and tryptophan metabolism-related therapies. Targeting liver-brain axis contains epigenetic regulation and Aβ metabolism-related therapies. In the future, a better understanding of gut-liver-brain axis interactions will promote the development of novel preventative strategies and the discovery of precise therapeutic targets in multiple diseases.

Probable targets and mechanism of ginsenoside Rg1 for non-alcoholic fatty liver disease: a study integrating network pharmacology, molecular docking, and molecular dynamics simulation

Ginsenoside Rg1 (GRg1), a key bioactive component of medicinal herbs, has shown beneficial effects on non-alcoholic fatty liver disease (NAFLD) and numerous other conditions. Nevertheless, the specific targets that are actively involved and the potential mechanisms underlying NAFLD treatment remain unclear. This study aimed to elucidate the therapeutic effects and mechanism of GRg1 in alleviating NAFLD using a combined approach of network pharmacology and molecular biology validation. The analysis yielded 294 targets for GRg1 and 1293 associated with NAFLD, resulting in 89 overlapping targets. Through protein-protein interactions (PPI) network topology analysis, 10 key targets were identified. Upon evaluating the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analysis, GRg1 may exert therapeutic effects on NAFLD by negatively regulating the apoptotic process, insulin and endocrine resistance, the AGE-RAGE signaling pathway in diabetic complications, and the Estrogen, PI3K/Akt, and MAPK pathways. The three differential gene targets for Akt1, EGFR, and IGF1 were identified through the compound-target network in conjunction with the aforementioned methods. The molecular docking and molecular dynamics (MD) simulations showed that AKT1 and EGFR had a strong binding affinity with GRg1. Overall, our findings point to a novel therapeutic strategy involving NAFLD, with further in vivo and in vitro studies promising to deepen our comprehension and validate its potential advantages.Communicated by Ramaswamy H. Sarma.

A Narrative Review on Strategies for the Reversion of Prediabetes to Normoglycemia: Food Pyramid, Physical Activity, and Self-Monitoring Innovative Glucose Devices

In 2019, "Nutrition Therapy for Adults with Diabetes or Prediabetes: A Consensus Report" was published. This consensus report, however, did not provide an easy way to illustrate to subjects with prediabetes (SwPs) how to follow a correct dietary approach. The purpose of this review is to evaluate current evidence on optimum dietary treatment of SwPs and to provide a food pyramid for this population. The pyramid built shows that everyday consumption should consist of: whole-grain bread or potatoes eaten with their skins (for fiber and magnesium) and low glycemic index carbohydrates (GI < 55%) (three portions); fruit and vegetables (5 portions), in particular, green leafy vegetables (for fiber, magnesium, and polyphenols); EVO oil (almost 8 g); nuts (30 g, in particular, pistachios and almonds); three portions of dairy products (milk/yogurt: 300-400 g/day); mineral water (almost 1, 5 L/day for calcium intake); one glass of wine (125 mL); and three cups of coffee. Weekly portions should include fish (four portions), white meat (two portions), protein plant-based food (four portions), eggs (egg portions), and red/processed meats (once/week). At the top of the pyramid, there are two pennants: a green one means that SwPs need some personalized supplementation (if daily requirements cannot be satisfied through diet, vitamin D, omega-3, and vitamin B supplements), and a red one means there are some foods and factors that are banned (simple sugar, refined carbohydrates, and a sedentary lifestyle). Three to four times a week of aerobic and resistance exercises must be performed for 30-40 min. Finally, self-monitoring innovative salivary glucose devices could contribute to the reversion of prediabetes to normoglycemia.

Characterization of gut microbiome composition in Iranian patients with nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Gut microbiota dysbiosis is intimately associated with development of non-alcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Nevertheless, the gut microbial community during the course of NAFLD and NASH is yet to be comprehensively profiled. This study evaluated alterations in fecal microbiota composition in Iranian patients with NAFLD and NASH compared with healthy individuals. This cross-sectional study enrolled 15 NAFLD, 15 NASH patients, and 20 healthy controls, and their clinical parameters were examined. The taxonomic composition of the fecal microbiota was determined by sequencing the V3-V4 region of 16S rRNA genes of stool samples. Compared to the healthy controls, NAFLD and NASH patients presented reduced bacterial diversity and richness. We noticed a reduction in the relative abundance of Bacteroidota and a promotion in the relative abundance of Proteobacteria in NAFLD and NASH patients. L-histidine degradation I pathway, pyridoxal 5'-phosphate biosynthesis I pathway, and superpathway of pyridoxal 5'-phosphate biosynthesis and salvage were more abundant in NAFLD patients than in healthy individuals. This study examined fecal microbiota dysbiosis in NAFLD and NASH patients and presented consistent results to European countries. These condition- and ethnicity-specific data could provide different diagnostic signatures and therapeutic targets.

Probiotic Pediococcus pentosaceus Li05 Improves Cholestasis through the FXR-SHP and FXR-FGF15 Pathways

Primary sclerosing cholangitis (PSC), a rare chronic cholestatic liver disease, is characterized by intrahepatic or extrahepatic strictures accompanied by biliary fibrosis. So far, there are no effective therapies to slow down the progression of this disease. Farnesoid X receptors (FXRs) are ligand-activated transcription factors involved in the control of bile acid (BA) synthesis and enterohepatic circulation. Therefore, targeting FXRs holds promise as a potential approach for treating PSC. Pediococcus pentosaceus Li05 is a probiotic that was isolated from healthy volunteers and has previously been shown to have an anti-inflammatory effect in DSS-induced colitis. In this study, we established a 3,5-diethoxycarbonyl-1,4-Dihydrocollidine (DDC)-induced cholestasis mouse model and investigated the effects of Pediococcus pentosaceus Li05 on PSC. Our findings revealed that administration of Li05 significantly attenuated liver damage, hepatic inflammation, and fibrosis, as well as bile duct hyperplasia. Li05 activated the hepatic FXR-SHP and ileal FXR-FGF15 signaling pathways to decrease the expression of Cyp7a1. In addition, the Li05-modulated gut microbiota structure especially improved the abundance of 7α-dehydroxylation bacteria like Eubacterium. The intervention of Li05 also improved the intestinal barrier and reduced bacterial endotoxin translocation. Based on these findings, Li05 shows promise for future application as a therapeutic strategy for cholestasis.

Effects of probiotics in patients with morbid obesity undergoing bariatric surgery: a systematic review and meta-analysis

BACKGROUND

Probiotics are commonly used after bariatric surgery. However, uncertainty remains regarding their effects. The purpose of this systematic review was to assess the effect of probiotics in patients with morbid obesity undergoing bariatric surgery.

METHODS

PubMed, Cochrane Library, Embase, Science Direct, and Web of Science were searched from inception to April 4, 2023. No language restrictions were applied. Relevant randomized controlled trials and controlled clinical trials were included. We used the aggregated data extracted from the trials and assessed the heterogeneity. When severe heterogeneity was detected, a random effect model was used. All stages of the review were done by independent authors.

RESULTS

We screened 2024 references and included 11 randomized controlled trials and controlled clinical trials. Compared with the protocol groups, probiotics showed significant effects on regulating aspartate amino transferase level (MD = -4.32 U/L; 95% CI [-7.10, -1.53], p = 0.002), triglycerides (MD = -20.16 mg/dL; 95% CI [-34.51, -5.82], p = 0.006), weight (MD = -1.99 kg; 95% CI [-3.97, -0.01], p = 0.05), vitamin B12 (MD = 2.24 pg/dL; 95% CI [-0.02, 4.51], p = 0.05), dietary energy (MD = -151.03 kcal; 95% CI [-215.68, -86.37], p < 0.00001), dietary protein (MD = -4.48 g/day, 95% CI [-8.76, -0.20], p = 0.04), dietary carbohydrate (MD = -34.25 g/day, 95% CI [-44.87, -23.62], p < 0.00001), and dietary fiber (MD = -2.17 g/day, 95% CI [-3.21, -1.14], p < 0.0001). There were no severe side effects related to probiotics.

CONCLUSIONS

Our meta-analysis suggested that probiotics may delay the progression of liver function injury, improve lipid metabolism, reduce weight, and reduce food intake, although the effects on other indicators were insignificant. Probiotics may be helpful for patients undergoing bariatric surgery. The review was registered on PROSPERO (International prospective register of systematic reviews): CRD42023407970. No primary source of funding.

Association between the gut microbiota and nonalcoholic fatty liver disease: A two-sample Mendelian randomization study

BACKGROUND

Increasing studies have shown that there is a significant association between gut microbiota and non-alcoholic fatty liver disease.

AIMS

To show the potential association between gut microbiota and non-alcoholic fatty liver disease, we performed a two-sample Mendelian randomization analysis.

METHODS

We analyzed summary statistics from genome-wide association studies of gut microbiota and non-alcoholic fatty liver disease and conducted Mendelian randomization studies to evaluate relationships between these factors.

RESULTS

Of the 211 gut microbiota taxa examined, the inverse variance weighted method identified Lactobacillaceae (OR = 0.83, 95% CI = 0.72 - 0.95, P = 0.007), Christensenellaceae (OR = 0.74, 95% CI = 0.59 - 0.92, P = 0.007), and Intestinibacter (OR = 0.85, 95% CI = 0.73 - 0.99, P = 0.035) were negatively correlated with non-alcoholic fatty liver disease. And Coriobacteriia (OR = 1.22, 95% CI = 1.01 - 1.42, P = 0.038), Actinomycetales (OR = 1.25, 95% CI = 1.02 - 1.53, P = 0.031), Oxalobacteraceae (OR = 1.10, 95% CI = 1.01 - 1.21, P = 0.036), Ruminococcaceae_UCG005 (OR = 1.18, 95% CI = 1.01 - 1.38, P = 0.033) are positively associated with non-alcoholic fatty liver disease.

CONCLUSIONS

Our study found that the abundance of certain strains was associated with the progression of nonalcoholic fatty liver disease.

Insights into the role of vitamin D in targeting the culprits of non-alcoholic fatty liver disease

Vitamin D (VD) is a secosteroid hormone that is renowned for its crucial role in phospho-calcium homeostasis upon binding to the nuclear vitamin D receptor (VDR). Over and above, the pleiotropic immunomodulatory, anti-inflammatory, and metabolic roles VD plays in different disease settings started to surface in the past few decades. On the other hand, a growing body of evidence suggests a correlation between non-alcoholic fatty liver disease (NAFLD) and its progressive inflammatory form non-alcoholic steatohepatitis (NASH) with vitamin D deficiency (VDD) owing to the former's ingrained link with obesity and metabolic syndrome. Accordingly, a better understanding of the contribution of disrupted VDR signalling to NAFLD incidence and progression would provide further insights into its diagnosis, treatment modalities, and prognosis. This is especially significant as, hitherto, no drug for NAFLD has been approved. This review, therefore, sought to set forth the likely contribution of VDR signalling in NAFLD and how it might influence its multiple drivers.