Amelioration of non-alcoholic fatty liver disease by sodium butyrate is linked to the modulation of intestinal tight junctions in db/db mice

Supplementation of Clostridium butyricum Alleviates Vascular Inflammation in Diabetic Mice

BACKGRUOUND

Gut microbiota is closely related to the occurrence and development of diabetes and affects the prognosis of diabetic complications, and the underlying mechanisms are only partially understood. We aimed to explore the possible link between the gut microbiota and vascular inflammation of diabetic mice.

METHODS

The db/db diabetic and wild-type (WT) mice were used in this study. We profiled gut microbiota and examined the and vascular function in both db/db group and WT group. Gut microbiota was analyzed by 16s rRNA sequencing. Vascular function was examined by ultrasonographic hemodynamics and histological staining. Clostridium butyricum (CB) was orally administered to diabetic mice by intragastric gavage every 2 days for 2 consecutive months. Reactive oxygen species (ROS) and expression of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were detected by fluorescence microscopy. The mRNA expression of inflammatory cytokines was tested by quantitative polymerase chain reaction.

RESULTS

Compared with WT mice, CB abundance was significantly decreased in the gut of db/db mice, together with compromised vascular function and activated inflammation in the arterial tissue. Meanwhile, ROS in the vascular tissue of db/db mice was also significantly increased. Oral administration of CB restored the protective microbiota, and protected the vascular function in the db/db mice via activating the Nrf2/HO-1 pathway.

CONCLUSION

This study identified the potential link between decreased CB abundance in gut microbiota and vascular inflammation in diabetes. Therapeutic delivery of CB by gut transplantation alleviates the vascular lesions of diabetes mellitus by activating the Nrf2/HO-1 pathway.

Sodium butyrate ameliorated diabetic nephropathy-associated tubulointerstitial inflammation by modulating the tight junctions of renal tubular epithelial cells

As one of the most significant pathological changes of diabetic nephropathy (DN), tubulointerstitial fibrosis (TIF) had a close relationship with tubulointerstitial inflammation (TI), and the occurrence of TI could have resulted from the disrupted tight junctions (TJs) of renal tubular epithelial cells (RTECs). Studies have demonstrated that sodium butyrate (NaB), a typical short chain fatty acid (SCFA), played an important regulatory role in intestinal TJs and inflammation. In this study, our in vivo and in vitro results showed that accompanied by TI, renal tubular TJs were gradually disrupted in the process of DN-related TIF. In HG and LPS co-cultured HK-2 cells and db/db mice, NaB treatment regained the TJs of RTECs via the sphingosine 1-phosphate receptor-1 (S1PR1)/AMPK signaling pathway, relieving inflammation. Small interfering RNA of S1PR1, S1PR1 antagonist W146 and agonist SEW2871, and AMPK agonist AICAR were all used to further confirm the essential role of the S1PR1/AMPK signaling pathway in NaB's TJ protection in RTECs in vitro. Finally, NaB administration not only improved the renal function and TIF, but also relieved the TI of db/db mice. These findings suggested that the use of NaB might be a potential adjuvant treatment strategy for DN-associated TIF, and this protective effect was linked to the TJ modulation of RTECs via the S1PR1/AMPK signaling pathway, leading to the improvement of TI.

Role of gut microbiota on regulation potential of Dendrobium officinale Kimura & Migo in metabolic syndrome: In-vitro fermentation screening and in-vivo verification in db/db mice

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium officinale Kimura & Migo (DEN) is a traditional medicine in China since Han dynasty. Decoction of its stem is often used in the treatment of Type-II diabetes (T2D), which is a typical metabolic disease accompanied with the impaired metabolic function of blood glucose and lipid.

AIM OF THE STUDY

Our study aimed to investigate the role of gut microbiota in differentiating DEN from different sources and its related pathway in the alleviation of metabolic syndromes induced by T2D.

MATERIALS AND METHODS

The aqueous extracts of four commercially available Dendrobium (DEN-1∼4) were prepared and screened through an in-vitro fermentation system. Based on their alterations in monosaccharide composition and short chain fatty acids (SCFA) formation during fermentation with db/db faecal fluid, one DEN extract was selected for further in vivo verification. The selected Dendrobium (DEN-4) was orally administered to db/db mice for 16 days once daily at the dosage of 200 mg/kg followed by evaluating its effect on blood glucose level, liver function and intestinal microenvironment including alterations of intestinal integrity and gut microbiota composition. In addition, liver metabolomics analysis was employed to reveal the related metabolic pathways.

RESULTS

Different extent of SCFA formation and utilization of monosaccharides were observed for the extracts of four DEN from different sources with a negative correlation between SCFA level and the ratio of Utilized glucose/Utilized mannose observed in the in-vitro fermentation system with db/db faecal fluid. DEN-4 with the highest SCFA formation during the in-vitro fermentation was selected and exhibited significantly hypoglycaemic effect in db/db mice with the alleviation of hepatic steatosis and impaired lipid homeostasis. Further mechanistic studies revealed that orally administered DEN-4 could improve the intestinal integrity of db/db mice via elevating their tight junction protein (ZO-1 and Occludin) expression in the colon and improve the diversity of gut microbiota with enhanced formation of SCFA. Moreover, metabolomics and KEGG pathway analysis of liver tissues suggested that the alleviated metabolic syndrome in db/db mice by DEN-4 might possibly be achieved through activation of PPAR pathway.

CONCLUSION

Our current study not only revealed the potential of gut microbiota in differentiating DEN from different sources, but also demonstrated that DEN exhibited its beneficial effect on the T2D induced metabolic syndrome possibly through enhancement of intestinal integrity and activation of PPAR pathway via gut-liver axis in db/db mice.

What are the common downstream molecular events between alcoholic and nonalcoholic fatty liver?

Liver fat storage, also called hepatic steatosis, is increasingly common and represents a very frequent diagnosis in the medical field. Excess fat is not without consequences. In fact, hepatic steatosis contributes to the progression toward liver fibrosis. There are two main types of fatty liver disease, alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). Although AFLD and NAFLD are similar in their initial morphological features, both conditions involve the same evolutive forms. Moreover, there are various common mechanisms underlying both diseases, including alcoholic liver disease and NAFLD, which are commonalities. In this Review, the authors explore similar downstream signaling events involved in the onset and progression of the two entities but not completely different entities, predominantly focusing on the gut microbiome. Downstream molecular events, such as the roles of sirtuins, cytokeratins, adipokines and others, should be considered. Finally, to complete the feature, some new tendencies in the therapeutic approach are presented.

Effects of short-chain fatty acids on blood glucose and lipid levels in mouse models of diabetes mellitus: A systematic review and network meta-analysis

Short-chain fatty acids (SCFAs), the main metabolites of gut microbiota, have been associated with lower blood glucose and lipid levels in diabetic mice. However, a comprehensive summary and comparison of the effects of different SCFA interventions on blood glucose and lipid levels in diabetic mice is currently unavailable. This study aims to compare and rank the effects of different types of SCFAs on blood glucose and lipid levels by collecting relevant animal research. A systematic search through PubMed, Embase, Cochrane Library, and Web of Science database was conducted to identify relevant studies from inception to March 17, 2023. Both pairwise meta-analysis and Bayesian network meta-analysis were used for statistical analyses. In total, 18 relevant studies involving 5 interventions were included after screening 3793 citations and 53 full-text articles. Notably, butyrate therapy (mean difference [MD] = -4.52, 95% confidence interval [-6.29, -2.75]), acetate therapy (MD = -3.12, 95% confidence interval [-5.79, -0.46]), and propionate therapy (MD = -2.96, 95% confidence interval [-5.66, -0.26]) significantly reduced the fasting blood glucose levels compared to the control group; butyrate therapy was probably the most effective intervention, with a surface under the cumulative ranking curve (SUCRA) value of 85.5%. Additionally, acetate plus propionate therapy was probably the most effective intervention for reducing total cholesterol (SUCRA = 85.8%) or triglyceride levels (SUCRA = 88.1%). These findings underscore the potential therapeutic implications of SCFAs for addressing metabolic disorders, particularly in type 2 diabetes mellitus.

Modulating intestinal barrier function by sphingosine-1-phosphate receptor 1 specific agonist SEW2871 attenuated ANIT-induced cholestatic hepatitis via the gut-liver axis

Bile acid (BA) homeostasis throughout the enterohepatic circulation system is a guarantee of liver physiological functions. BA circulation disorders is one of the characteristic clinical manifestations of cholestasis, and have a closely relationship with intestinal barrier function, especially ileum. Here, our in vivo and in vitro studies showed that intestinal tight junctions (TJs) were disrupted by α-naphthylisothiocyanate (ANIT), which also down-regulated the protein expression of sphingosine-1-phosphate receptor 1 (S1PR1) in the top of villus of mice ileum. Activating S1PR1 by specific agonist SEW2871 could improve TJs via inhibiting ERK1/2/LKB1/AMPK signaling pathway in the ileum of ANIT-treated mice and ANIT-cultured Caco-2 cells. SEW2871 not only regained ileum TJs by activating S1PR1 in the epithelial cells of ileum mucosa, but also recovered ileum barrier function, which was further verified by the recovered BA homeostasis in mice ileum (content and tissue) by using of high-performance liquid chromatographytandem mass spectrometry (LC-MS/MS). Subsequently, the improved intestinal injury and inflammation further strengthened that SEW2871 modulated intestinal barrier function in ANIT-treated mice. Finally, our data revealed that along with the down-regulated levels of serum lipopolysaccharides (LPS), SEW2871 improved liver function and relieved hepatitis via blocking TLR4/MyD88/NF-kB signaling pathway in ANIT-treated mice. In conclusion, these results demonstrated that activating intestinal S1PR1 by SEW2871 could modulate intestinal barrier function, leading to the improvement of cholestatic hepatitis in ANIT-treated mice via the "gut-liver" axis.

Mulberry leaf flavonoids activate BAT and induce browning of WAT to improve type 2 diabetes via regulating the AMPK/SIRT1/PGC-1α signaling pathway

Mulberry (Morus alba L.) leaf is a well-established traditional Chinese botanical and culinary resource. It has found widespread application in the management of diabetes. The bioactive constituents of mulberry leaf, specifically mulberry leaf flavonoids (MLFs), exhibit pronounced potential in the amelioration of type 2 diabetes (T2D). This potential is attributed to their ability to safeguard pancreatic β cells, enhance insulin resistance, and inhibit α-glucosidase activity. Our antecedent research findings underscore the substantial therapeutic efficacy of MLFs in treating T2D. However, the precise mechanistic underpinnings of MLF's anti-T2D effects remain the subject of inquiry. Activation of brown/beige adipocytes is a novel and promising strategy for T2D treatment. In the present study, our primary objective was to elucidate the impact of MLFs on adipose tissue browning in db/db mice and 3T3-L1 cells and elucidate its underlying mechanism. The results manifested that MLFs reduced body weight and food intake, alleviated hepatic steatosis, improved insulin sensitivity, and increased lipolysis and thermogenesis in db/db mice. Moreover, MLFs activated brown adipose tissue (BAT) and induced the browning of inguinal white adipose tissue (IWAT) and 3T3-L1 adipocytes by increasing the expressions of brown adipocyte marker genes and proteins such as uncoupling protein 1 (UCP1) and beige adipocyte marker genes such as transmembrane protein 26 (Tmem26), thereby promoting mitochondrial biogenesis. Mechanistically, MLFs facilitated the activation of BAT and the induction of WAT browning to ameliorate T2D primarily through the activation of AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling pathway. These findings highlight the unique capacity of MLF to counteract T2D by enhancing BAT activation and inducing browning of IWAT, thereby ameliorating glucose and lipid metabolism disorders. As such, MLFs emerge as a prospective and innovative browning agent for the treatment of T2D.

Butyrate restores the fat/lean mass ratio balance and energy metabolism and reinforces the tight junction-mediated intestinal epithelial barrier in prediabetic mice independently of its anti-inflammatory and epigenetic actions

Tissue/cellular actions of butyrate on energy metabolism and intestinal barrier in normal metabolic conditions or prediabetes are still unclear. In this work, we investigated the beneficial effect of dietary supplementation with sodium butyrate on energy metabolism, body mass composition, and intestinal epithelial barrier mediated by tight junction (TJ) in chow diet-fed normal and high-fat diet (HF)-fed prediabetic mice, considering the well-known butyrate action as an epigenetic and inflammatory regulator. Butyrate significantly reduced the fat/lean mass ratio, slightly ameliorated dyslipidemia, restored oral glucose tolerance, and increased basal energy expenditure in prediabetic HF-fed mice but had no effect on control animals. Such effects were observed in the absence of significant alterations in the hypothalamic expression of orexigenic and anorexigenic genes and motor activity. Also, butyrate suppressed the whitening effect of HF on brown adipose tissue but did not affect cell bioenergetics in immortalized UCP1-positive adipocytes in vitro. Butyrate reinforced the intestinal epithelial barrier in HF-fed mice and in Caco-2 monolayers, which involved higher trafficking of TJ proteins to the cell-cell contact region of the intestinal epithelia, without affecting TJ gene expression or the acetylation level of histones H3 and H4 in vivo. All metabolic and intestinal effects of butyrate in prediabetic mice occurred in the absence of detectable changes in systemic or local inflammation, or alterations in endotoxemia markers. Butyrate has no effect on chow diet-fed mice but, in the context of HF-induced prediabetes, it prevents metabolic and intestinal dysfunctions independently of its anti-inflammatory and epigenetic actions.

Targeting mTOR/YY1 signaling pathway by quercetin through CYP7A1-mediated cholesterol-to-bile acids conversion alleviated type 2 diabetes mellitus induced hepatic lipid accumulation

BACKGROUND

Hepatic lipid accumulation was a major promoter for the further development of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes (T2DM). mTOR/YY1 signaling pathway regulated many metabolic processes in different organs, and played an important role in hepatic lipid metabolism. Thus, targeting mTOR/YY1 signaling pathway might be a novel therapeutic strategy of T2DM-associated NALFD.

PURPOSE

To investigate the effects and the mechanism of quercetin against T2DM-associated NAFLD.

STUDY DESIGN AND METHODS

The combine abilities of 24 flavonoid compounds with mTOR were detected by computer virtual screening (VS) and molecular modeling. mTOR/YY1 signaling pathway was examined in the liver of db/db mice, and high glucose (HG) and free fatty acid (FFA) co-cultured HepG2 cells. YY1 overexpression lentivirus vector and mTOR specific inhibitor rapamycin were used to further identify the indispensable role of mTOR/YY1 signaling pathway in quercetin's amelioration effect of hepatic lipid accumulation in vitro. Clinical studies, luciferase assay and chromatin immunoprecipitation (ChIP) assay were all carried out to investigate the potential mechanisms by which quercetin exerted its amelioration effect of hepatic lipid accumulation.

RESULTS

Quercetin had the strongest ability to combine with mTOR and could competitively occupy its binding pocked. Along with the alleviated hepatic injury by quercetin, mTOR/YY1 signaling pathway was down-regulated in vivo and in vitro. However, the alleviation effect of quercetin against hepatic lipid accumulation was inhibited by YY1 overexpression in vitro. Mechanistically, the down-regulated nuclear YY1 induced by quercetin directly bound to CYP7A1 promoter and activated its transcription, resulting in the restoration of cholesterol homeostasis via the conversion of cholesterol-to-bile acids (BAs).

CONCLUSION

The hepatoprotective effect of quercetin on T2DM-associated NAFLD was linked to the restoration of cholesterol homeostasis by the conversion of cholesterol-to-BAs via down-regulating mTOR/YY1 signaling pathway, leading to the increased CYP7A1 activity.

Ampicillin exacerbates acetaminophen-induced acute liver injury by inducing intestinal microbiota imbalance and butyrate reduction

BACKGROUND AND AIMS

Antibiotics (ATBx) and acetaminophen (APAP) are widely used worldwide. APAP is the most common cause of acute liver injury (ALI) and might be used in combination with ATBx in clinics. However, the impact of ATBx on APAP-induced ALI has rarely been studied.

METHODS

First, we compared the effects of seven ATBx on APAP-induced ALI. Then, we analysed faecal, serum and liver samples to investigate the impact of the gut microbiota on this process. Finally, we assessed the role of short-chain fatty acids in this process.

RESULTS

In this work, we found that the ALI was significantly aggravated in the mice treated with ampicillin (Amp) instead of other ATBx. Amp exposure reduced the diversity and altered the composition of gut microbiota. The altered gut microbiota aggravated APAP-induced ALF, which was proven by faecal microbiota transplantation from ATBx-treated mice. Metagenomic analysis showed a significantly decreased Lactobacillus abundance in Amp-treated mice. Gavage with Lactobacillus, especially Lactobacillus rhamnosus, significantly reversed the severer ALF induced by APAP and Amp. Moreover, Lactobacillus supplementation increased butyrate-producing clostridia and lowered butyrate levels in Amp-treated mice. In accordance, butyrate supplementation could also alleviate Amp-aggravated ALI. In addition, inhibition of nuclear factor erythroid 2-related factor 2 counteracted the protective effect of butyrate on aggravated ALI induced by Amp and APAP.

CONCLUSION

Together, this study revealed a potential health impact of Amp that may exacerbate liver damage when co-exposed to excess APAP.

Self-assembling polymer-based short chain fatty acid prodrugs ameliorate non-alcoholic steatohepatitis and liver fibrosis

With the preponderance of a high-calorie diet and sedentary lifestyle, the prevalence of non-alcoholic steatohepatitis (NASH), a state of abnormally elevated lipid accumulation in the liver with chronic inflammation, is increasing at an alarming rate worldwide. Hence, cost-effective therapeutic interventions are required to manage this disease at an early stage. Numerous reports have suggested a link between gut microbial dysbiosis, particularly a decrease in the abundance of short-chain fatty acids (SCFA)-producing microbiota and NASH pathogenesis. Considering these low molecular weight (LMW) SCFAs such as acetic, propionic, and butyric acids have been used to inhibit hepatic steatosis in mouse models. However, the poor pharmacokinetic (PK) profile of SCFAs, caused due to their LMW, renders them therapeutically ineffective. Thus, to improve the PK characteristic-based therapeutic efficacy of LMW SCFAs, we designed SCFA-based prodrugs that possess self-assembling characteristics in aqueous media. The designed SCFA prodrugs consist of enzyme-metabolizable amphiphilic block copolymers, [poly(ethylene glycol)-b-poly(vinyl ester)s] conjugated to propionic acid (PA) or butyric acid (BA) by an ester linkage, which self-assemble into stable nanosized micelles several tens of nanometers in diameter (Nano^PA and Nano^BA). Via pharmacological analysis, we confirmed that, after oral administration, LMW BA decreased to a physiological level within 24 h in the liver, whereas BA liberated from Nano^BA was observed until 72 h post-administration, implying a sustained release profile. Here, we evaluated the therapeutic efficacy of Nano^SCFA in a choline-deficient, L-amino acid-defined high-fat diet (CDAHFD)-induced NASH and liver fibrosis mouse model by ad libitum drinking. Nano^SCFA, particularly Nano^BA, exhibited the remarkable potential to ameliorate the phenotypic features of fatty liver disease by reducing hepatic lipogenesis and fibrosis, with negligible adverse effects. In contrast, conventional LMW SCFAs failed to prevent the pathogenesis of fatty liver disease, which plausibly can be explained by their rapid clearance and discernible adverse effects. Mechanistic studies revealed that Nano^BA restored the nuclear expression of PPARα, a transcriptional factor regulating mitochondrial fatty acid oxidation, in the periportal hepatocytes and decreased the CPT1A expression level in the hepatic tissues, reflecting the therapeutic effects of Nano^BA. Taken together, we confirmed that our Nano^SCFA potentially improved the PK properties of SCFAs, and it consequently alleviated NASH symptoms and fibrotic liver compared to LMW SCFAs. Our study establishes Nano^SCFA as a suitable nano-assembled prodrug for NASH treatment.

Targeted Delivery of Butyrate Improves Glucose Homeostasis, Reduces Hepatic Lipid Accumulation and Inflammation in db/db Mice

Butyrate produced by the gut microbiota has beneficial effects on metabolism and inflammation. Butyrate-producing bacteria are supported by diets with a high fiber content, such as high-amylose maize starch (HAMS). We investigated the effects of HAMS- and butyrylated HAMS (HAMSB)-supplemented diets on glucose metabolism and inflammation in diabetic db/db mice. Mice fed HAMSB had 8-fold higher fecal butyrate concentration compared to control diet-fed mice. Weekly analysis of fasting blood glucose showed a significant reduction in HAMSB-fed mice when the area under the curve for all five weeks was analyzed. Following treatment, fasting glucose and insulin analysis showed increased homeostatic model assessment (HOMA) insulin sensitivity in the HAMSB-fed mice. Glucose-stimulated insulin release from isolated islets did not differ between the groups, while insulin content was increased by 36% in islets of the HAMSB-fed mice. Expression of insulin 2 was also significantly increased in islets of the HAMSB-fed mice, while no difference in expression of insulin 1, pancreatic and duodenal homeobox 1, MAF bZIP transcription factor A and urocortin 3 between the groups was observed. Hepatic triglycerides in the livers of the HAMSB-fed mice were significantly reduced. Finally, mRNA markers of inflammation in liver and adipose tissue were reduced in mice fed HAMSB. These findings suggest that HAMSB-supplemented diet improves glucose metabolism in the db/db mice, and reduces inflammation in insulin-sensitive tissues.

Butyrate Attenuates Hepatic Steatosis Induced by a High-Fat and Fiber-Deficient Diet via the Hepatic GPR41/43-CaMKII/HDAC1-CREB Pathway

SCOPE

Hepatic steatosis is a major health issue that can be attenuated by a healthy diet. This study investigates the effects and molecular mechanisms of butyrate, a dietary fiber metabolite of gut microbiota, on lipid metabolism in hepatocytes.

METHODS AND RESULTS

This study examines the effects of butyrate (0-8 mM) on lipid metabolism in primary hepatocytes. The results show that butyrate (2 mM) consistently inhibits lipogenic genes and activates lipid oxidation-related gene expression in hepatocytes. Furthermore, butyrate modulates lipid metabolism genes, reduces fat droplet accumulation, and activates the calcium/calmodulin-dependent protein kinase II (CaMKII)/histone deacetylase 1 (HDAC1)-cyclic adenosine monophosphate response element binding protein (CREB) signaling pathway in the primary hepatocytes and liver of wild-type (WT) mice, but not in G-protein-coupled receptor 41 (GPR41) knockout and 43 (GPR43) knockout mice. This suggests that butyrate regulated hepatic lipid metabolism requires GPR41 and GPR43. Finally, the study finds that dietary butyrate supplementation (5%) ameliorates hepatic steatosis and abnormal lipid metabolism in the liver of mice fed a high-fat and fiber-deficient diet for 15 weeks.

CONCLUSION

This work reveals that butyrate improves hepatic lipid metabolism through the GPR41/43-CaMKII/HDAC1-CREB pathway, providing support for consideration of butyrate as a dietary supplement to prevent the progression of NAFLD induced by the Western-style diet.

Enhancing intestinal barrier efficiency: A novel metabolic diseases therapy

Physiologically, the intestinal barrier plays a crucial role in homeostasis and nutrient absorption and prevents pathogenic entry, harmful metabolites, and endotoxin absorption. Recent advances have highlighted the association between severely damaged intestinal barriers and diabetes, obesity, fatty liver, and cardiovascular diseases. Evidence indicates that an abated intestinal barrier leads to endotoxemia associated with systemic inflammation, insulin resistance, diabetes, and lipid accumulation, accelerating obesity and fatty liver diseases. Nonetheless, the specific mechanism of intestinal barrier damage and the effective improvement of the intestinal barrier remain to be explored. Here, we discuss the crosstalk between changes in the intestinal barrier and metabolic disease. This paper also highlights how to improve the gut barrier from the perspective of natural medicine, gut microbiota remodeling, lifestyle interventions, and bariatric surgery. Finally, potential challenges and prospects for the regulation of the gut barrier-metabolic disease axis are discussed, which may provide theoretical guidance for the treatment of metabolic diseases.

Mechanistic insights into the pleiotropic effects of butyrate as a potential therapeutic agent on NAFLD management: A systematic review

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic diseases worldwide. As a multifaceted disease, NAFLD's pathogenesis is not entirely understood, but recent evidence reveals that gut microbiota plays a significant role in its progression. Butyrate, a gut microbiota metabolite, has been reported to have hepato-protective effects in NAFLD animal models. The purpose of this systematic review is to determine how butyrate affects the risk factors for NAFLD. Searches were conducted using relevant keywords in electronic databases up to March 2022. According to the evidence presented in this study, butyrate contributes to a wide variety of biological processes in the gut-liver axis. Its beneficial properties include improving intestinal homeostasis and liver health as well as anti-inflammatory, metabolism regulatory and anti-oxidative effects. These effects may be attributed to butyrate's ability to regulate gene expression as an epigenetic modulator and trigger cellular responses as a signalling molecule. However, the exact underlying mechanisms remain unclear. Human trials have not been performed on the effect of butyrate on NAFLD, so there are concerns about whether the results of animal studies can be translated to humans. This review summarises the current knowledge about the properties of butyrate, particularly its potential effects and mechanisms on liver health and NAFLD management.

Molecular mechanism of Ginkgo biloba in treating type 2 diabetes mellitus combined with non-alcoholic fatty liver disease based on network pharmacology, molecular docking, and experimental evaluations

Ginkgo biloba has gained increasing attention owing to its remarkable effects against cardiovascular disease. However, the role of G. biloba in hepatic lipid metabolism disorders in type 2 diabetes mellitus (T2DM) combined with non-alcoholic fatty liver disease (NAFLD) and its underlying mechanisms have not been elucidated. Here, the effective ingredients and mechanisms of action of G. biloba in T2DM combined with NAFLD were investigated via an integrated strategy of network pharmacology and molecular docking. Thirty-four core targets for the alleviation of T2DM combined with NAFLD were identified and retrieved from multiple open-source databases, after validating the ameliorative effect of G. biloba on lipid accumulation in vitro. The targets IL6, IL1B, VEGFA, PTGS2, and CCL2, among others, with high network association values, were screened using Cytoscape. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that 34 compounds derived from G. biloba may exert therapeutic effects via response to molecule of bacterial origin, cellular response to lipid, and response to the hormone. In addition, the AGE-RAGE and IL-17 signaling pathways were predicted to be most significantly affected. Meanwhile, the outcomes of the molecular docking experiment showed that the most effective ingredients in G. biloba showed a strong binding affinity to the potential target active sites. Findings from further in vitro experiments confirmed that G. biloba treatment decreased the level of IL6, IL1B, and VEGFA protein. In conclusion, our findings provided novel insights into the mechanisms underlying the therapeutic effect of G. biloba in T2DM combined with NAFLD. PRACTICAL APPLICATIONS: As a medicinal food plant, G. biloba has been shown to exert benefits in cardiovascular diseases. However, the pharmacological material basis and complex mechanism of action in G. biloba in T2DM combined with NAFLD remain unknown. Here, the mechanism by which G. biloba could ameliorate T2DM combined with NAFLD was investigated, and the potential target and molecular mechanism were explored, through a comprehensive strategy combining network pharmacology and molecular docking. Our findings indicate that G. biloba exerts synergistic effects in treating T2DM combined with NAFLD through multi-ingredients, multi-targets, and multi-pathways; the findings also elucidate the nutritional and therapeutic potential of G. biloba in preventing and treating T2DM combined with NAFLD and provides robust evidence for its clinical application.

Butyrate to combat obesity and obesity-associated metabolic disorders: Current status and future implications for therapeutic use

Evidence is increasing that disturbances in the gut microbiome may play a significant role in the etiology of obesity and type 2 diabetes. The short chain fatty acid butyrate, a major end product of the bacterial fermentation of indigestible carbohydrates, is reputed to have anti-inflammatory properties and positive effects on body weight control and insulin sensitivity. However, whether butyrate has therapeutic potential for the treatment and prevention of obesity and obesity-related complications remains to be elucidated. Overall, animal studies strongly indicate that butyrate administered via various routes (e.g., orally) positively affects adipose tissue metabolism and functioning, energy and substrate metabolism, systemic and tissue-specific inflammation, and insulin sensitivity and body weight control. A limited number of human studies demonstrated interindividual differences in clinical effectiveness suggesting that outcomes may depend on the metabolic, microbial, and lifestyle-related characteristics of the target population. Hence, despite abundant evidence from animal data, support of human data is urgently required for the implementation of evidence-based oral and gut-derived butyrate interventions. To increase the efficacy of butyrate-focused interventions, future research should investigate which factors impact treatment outcomes including baseline gut microbial activity and functionality, thereby optimizing targeted-interventions and identifying individuals that merit most from such interventions.

Effects of Maternal Gut Microbiota-Targeted Therapy on the Programming of Nonalcoholic Fatty Liver Disease in Dams and Fetuses, Related to a Prenatal High-Fat Diet

Metabolic disorders can start in utero. Maternal transmission of metabolic phenotypes may increase the risks of adverse metabolic outcomes, such as nonalcoholic fatty liver disease (NAFLD); effective intervention is essential to prevent this. The gut microbiome plays a crucial role in fat storage, energy metabolism, and NAFLD. We investigated the therapeutic use of probiotic Lactobacillus reuteri and postbiotic butyrate gestation in the prevention of perinatal high-fat diet-induced programmed hepatic steatosis in the offspring of pregnant Sprague–Dawley rats who received regular chow or a high-fat (HF) diet 8 weeks before mating. L. reuteri or sodium butyrate was administered via oral gavage to the gestated rats until their sacrifice on day 21 of gestation. Both treatments improved liver steatosis in pregnant dams; L. reuteri had a superior effect. L. reuteri ameliorated obesity and altered the metabolic profiles of obese gravid dams. Maternal L. reuteri therapy prevented maternal HF diet-induced fetal liver steatosis, and reformed placental remodeling and oxidative injury. Probiotic therapy can restore lipid dysmetabolism in the fetal liver, modulate nutrient-sensing molecules in the placenta, and mediate the short-chain fatty acid signaling cascade. The therapeutic effects of maternal L. reuteri on maternal NAFLD and NAFLD reprogramming in offspring should be validated for further clinical translation.

The effect of increasing intestinal short-chain fatty acid concentration on gut permeability and liver injury in the context of liver disease: A systematic review

BACKGROUND AND AIM

The gut barrier protects the liver through tight junctions, which are disrupted in liver disease either from dysbiosis, inflammation, or the effects of ingested compounds such as alcohol. Strengthening of the gut barrier may ameliorate liver injury of varying etiologies. Short chain fatty acids (SCFAs) have been shown to improve gut barrier function. This systematic review aims to synthesize all studies that have trialed SCFA supplementation as a therapy for liver disease.

METHODS

A systematic review assessing the impact of SCFA supplementation on liver injury and intestinal permeability was conducted. All forms of intervention that specifically increased intestinal SCFA concentration and measured both liver injury and permeability were eligible. Two independent reviewers assessed each study for outcomes, risk of bias, and quality using checklists relevant to the study's methodology.

RESULTS

Seventeen studies were identified; two utilized a human model (15 murine). Fifty-eight markers of liver injury were identified, with 26 different measures of permeability. Given the numerous designs, no meta-analysis was possible. SCFA supplements included oral and enteral butyrate, probiotics, and prebiotics. Fourteen studies demonstrated improved permeability. All studies showed a significant amelioration of liver injury.

CONCLUSIONS

Short chain fatty acid supplementation to reduce intestinal permeability represents a potential therapy in a variety of liver disease models. A large number of outcome measures were reported however not all are practical in human studies. Future work should evaluate methods to increase luminal SCFA concentrations and the effect of this on gut permeability and liver inflammation in people with liver disease.

A potential link between plasma short‑chain fatty acids, TNF‑α level and disease progression in non‑alcoholic fatty liver disease: A retrospective study

The onset and progression of non-alcoholic fatty liver disease (NAFLD) remains unclear, but short-chain fatty acids (SCFAs) in circulation may participate in its pathogenesis by acting as inflammation inhibitors. The aim of this retrospective study was to investigate plasma concentrations of general SCFAs in healthy individuals and in patients with distinct stages of NAFLD. Three main SCFAs (including acetate, propionate and butyrate) were analyzed by gas chromatography. The plasma TNF-α concentration was measured by ELISA. One-way ANOVA, Spearman's correlation and Pearson's correlation analysis were performed to estimate the associations between SCFAs, TNF-α and disease progression. Multiple linear stepwise regression was computed to explore the predictor variables of TNF-α in circulation. A total of 71 patients with NAFLD [including 27 patients with NAFL, 20 patients with non-alcoholic steatohepatitis (NASH) and 24 patients with NAFLD-related cirrhosis (NAFLD-cirrhosis)] and 9 healthy control (HC) subjects were enrolled for analysis. Although not statistically significant, plasma SCFAs were elevated in patients with NAFL compared with HC subjects, whereas the vast majority of SCFAs were statistically reduced in patients with NASH or NAFLD-cirrhosis compared with patients with NAFL. Plasma SCFAs had no significant differences in NASH or NAFLD-cirrhosis patients compared with HC subjects. In addition, significant negative correlations were observed between TNF-α and SCFAs. The progression of NAFLD (β=0.849; P<0.001) and the decline of the total three SCFA concentrations (β=-0.189; P<0.001) were recognized as independent risk variables related to the elevated peripheral TNF-α in the multiple linear stepwise regression model. Plasma SCFA concentrations may alter with the development of NAFLD and may have a potential link to TNF-α and the progression of NAFLD, which may serve a protective role toward disease advancement. Further mechanistic studies, such as analysis of gastrointestinal microecology, signaling pathways and functions involved in TNF-α, need to be performed. Also, therapeutic supplementation of SCFAs for NASH and NAFLD-cirrhosis needs further research and verification.

Hesperetin, a Promising Treatment Option for Diabetes and Related Complications: A Literature Review

The morbidity and mortality of diabetes have increased dramatically in recent decades. Novel strategies for treating diabetes and its complications with minimal side effects are in urgent need. New monomeric molecules extracted from herbal medicine, which is a form of alternative medicine, are being sought as drug candidates for the treatment of diabetes and its complications. Hesperetin (Hst), a citrus flavonoid, is of increasing interest in scientific studies recently due to its properties in combating diabetes and its complications, whereas existing studies are scattered and unsystematic. Here, we summarized the literature studies over the last 10 years to review the potential therapeutic role of Hst in the prevention and mitigation of diabetes and its complications, intending to provide promising strategies for the clinical management of diabetes and its complications.

Astragalus mongholicus polysaccharides ameliorate hepatic lipid accumulation and inflammation as well as modulate gut microbiota in NAFLD rats

Hepatic lipid accumulation, inflammation and gut microbiota dysbiosis are hallmarks of non-alcoholic fatty liver disease (NAFLD), which is the leading cause of chronic liver disease with no therapeutic consensus. The aim of the present study was to elucidate the mechanism of the effects of Astragalus mongholicus polysaccharides (mAPS) on lipid metabolism, inflammation and gut microbiota in a rat model of NAFLD induced by a high-fat diet (HFD). Our results showed that mAPS and Berberine supplementation reduced HFD-induced increases in body weight, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and homeostasis model assessment of insulin resistance (HOMA-IR), and these changes were accompanied by improved histological changes in the liver. Moreover, administration of mAPS and Berberine resulted in lower levels of serum triglycerides, total cholesterol and low-density lipoprotein cholesterol (LDL-c) but higher levels of high-density lipoprotein cholesterol (HDL-c) in HFD-fed rats. mAPS and Berberine treatment markedly reduced HFD-induced hepatic lipid accumulation, which was associated with increased expression of phosphorylated- adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-α (PPAR-α) but decreased expression of sterol-regulatory element binding proteins (SREBP-1). Pretreatment with mAPS or Berberine reduced HFD-induced expression of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α). In addition, mAPS downregulated the expression of colonic and hepatic Toll-like receptor 4 (TLR4) as well as phosphorylated- nuclear factor-κB (NF-κB) and nucleotide-binding domain, leucine-rich repeat-containing receptor, pyrin domain-containing-3 (NLRP3) but upregulated the expression of zonula occludens-1 (ZO-1) and occludin in HFD-fed rats. Notably, mAPS treatment reshaped the intestinal microbiome by lowering the Firmicutes to Bacteroidetes (F/B) ratio and increasing the abundance of Proteobacteria and Epsilonbacteria. mAPS supplementation had little effect on the profile of fecal short-chain fatty acids (SCFAs), but it significantly decreased the expression of colonic and hepatic G-protein coupled receptor (GPR) 41 and 43. Therefore, mAPS supplementation ameliorates hepatic inflammation and lipid accumulation in NAFLD by modulating the gut microbiota and SCFA-GPR signaling pathways. The present study provides new evidence for mAPS as a natural active substance in the treatment of NAFLD.

Bentong ginger oleoresin mitigates liver injury and modulates gut microbiota in mouse with nonalcoholic fatty liver disease induced by high-fat diet

The present study aimed to examine the protective effect of Bentong ginger oleoresin (BGO) on the occurrence of nonalcoholic fatty liver disease (NAFLD) and its underlying mechanism. In the present study, 14-week BGO treatment reduced the high-fat diet (HFD)-induced obesity. The serum total cholesterol (TC) was reduced from 4.76 ± 0.30 to 3.542 ± 0.49 mmol/L and fatty liver score decreased to the normal level (1.6 ± 0.55). BGO had antihypercholesterolemia activity, alleviated abnormal lipid metabolism, and improved liver fat accumulation. In addition, liver inflammatory cytokine tests and Western blotting analysis indicated that BGO might play an anti-inflammatory role by mediating the NF-κB signaling pathway. Moreover, BGO regulated the gut microbiota in NAFLD mice and finally mediated their benefits for the host, which might be associated with reduced abundance of Lachnospiraceae_NK4A136_group and Fournierella. BGO showed effective liver protection and regulation of gut microbiota for the HFD-induced NAFLD in obese mice. As a result, BGO may serve as an effective dietary supplement for the improvement of NAFLD-related metabolic diseases. PRACTICAL APPLICATION: This study provides a new way to improve the added value of Bentong ginger. It also provides certain experimental data on BGO as a kind of the functional food ingredient. The current work also provides new ideas for the improvement and treatment of NAFLD.

The Role of Gut–Liver Axis in Gut Microbiome Dysbiosis Associated NAFLD and NAFLD-HCC

Nonalcoholic fatty liver disease (NAFLD) is considered as one of the most prevalent chronic liver diseases worldwide due to the rapidly rising prevalence of obesity and metabolic syndrome. As a hepatic manifestation of metabolic disease, NAFLD begins with hepatic fat accumulation and progresses to hepatic inflammation, termed as non-alcoholic steatohepatitis (NASH), hepatic fibrosis/cirrhosis, and finally leading to NAFLD-related hepatocellular carcinoma (NAFLD-HCC). Accumulating evidence showed that the gut microbiome plays a vital role in the initiation and progression of NAFLD through the gut–liver axis. The gut–liver axis is the mutual communication between gut and liver comprising the portal circulation, bile duct, and systematic circulation. The gut microbiome dysbiosis contributes to NAFLD development by dysregulating the gut–liver axis, leading to increased intestinal permeability and unrestrained transfer of microbial metabolites into the liver. In this review, we systematically summarized the up-to-date information of gut microbiome dysbiosis and metabolomic changes along the stages of steatosis, NASH, fibrosis, and NAFLD-HCC. The components and functions of the gut–liver axis and its association with NAFLD were then discussed. In addition, we highlighted current knowledge of gut microbiome-based treatment strategies targeting the gut–liver axis for preventing NAFLD and its associated HCC.

Native and Engineered Probiotics: Promising Agents against Related Systemic and Intestinal Diseases

Intestinal homeostasis is a dynamic balance involving the interaction between the host intestinal mucosa, immune barrier, intestinal microecology, nutrients, and metabolites. Once homeostasis is out of balance, it will increase the risk of intestinal diseases and is also closely associated with some systemic diseases. Probiotics (Escherichia coli Nissle 1917, Akkermansia muciniphila, Clostridium butyricum, lactic acid bacteria and Bifidobacterium spp.), maintaining the gut homeostasis through direct interaction with the intestine, can also exist as a specific agent to prevent, alleviate, or cure intestinal-related diseases. With genetic engineering technology advancing, probiotics can also show targeted therapeutic properties. The aims of this review are to summarize the roles of potential native and engineered probiotics in oncology, inflammatory bowel disease, and obesity, discussing the therapeutic applications of these probiotics.

Sodium butyrate alleviates intestinal injury and microbial flora disturbance induced by lipopolysaccharides in rats

Sodium butyrate alleviates LPS-induced intestinal inflammation in rats by regulating intestinal injury, inflammatory cytokine levels, and intestinal flora.

Knockdown of Sirt1 Gene in Mice Results in Lipid Accumulation in the Liver Mediated via PGC-1α-Induced Mitochondrial Dysfunction and Oxidative Stress

The study demonstrated the crucial role of Sirt1 gene in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) related to the influence of Sirt1 on oxidative stress and glycolipid metabolism. The 16-week-old genetically diabetic db/db mice were characterized with downregulated expression of Sirt1 in the liver accompanied by hepatomegaly and a larger size of fat vacuoles in hepatocytes. In db/m mice, silencing Sirt1 gene induced hepatic steatosis and significantly increased serum AST. Additionally, the levels of triglycerides in blood and liver of these mice were elevated. However, all pathological changes in the liver of Sirt1-knockdown db/m mice were less pronounced than in 16-week-old db/db mice. Further experiments showed that oxidative stress and PGC-1α-mediated mitochondrial dysfunction are implicated in pathological changes of lipid metabolism in T2DM-induced NAFLD provoked by Sirt1 silencing. This study showed that down-regulation of Sirt1 expression plays the key role in pathological processes developed during T2DM-induced abnormalities of lipid metabolism in the liver. Thus, up-regulation of Sirt1 expression seems to be a promising strategy in early prevention of T2DM-induced NAFLD.

Butyrate Alters Pyruvate Flux and Induces Lipid Accumulation in Cultured Colonocytes

Butyrate is considered the primary energy source of colonocytes and has received wide attention due to its unique health benefits. Insight into the mechanistic effects of butyrate on cellular and metabolic function relies mainly on research in in-vitro-cultured cells. However, cells in culture differ from those in vivo in terms of metabolic phenotype and nutrient availability. For translation, it is therefore important to understand the impact of different nutrients on the effects of butyrate. We investigated the metabolic consequences of butyrate exposure under various culturing conditions, with a focus on the interaction between butyrate and glucose. To investigate whether the effects of butyrate were different between cells with high and low mitochondrial capacity, we cultured HT29 cells under either low- (0.5 mM) or high- (25 mM) glucose conditions. Low-glucose culturing increased the mitochondrial capacity of HT29 cells compared to high-glucose (25 mM) cultured HT29 cells. Long-term exposure to butyrate did not alter mitochondrial bioenergetics, but it decreased glycolytic function, regardless of glucose availability. In addition, both high- and low-glucose-grown HT29 cells showed increased lipid droplet accumulation following long-term butyrate exposure. Acute exposure of cultured cells (HT29 and Caco-2) to butyrate increased their oxygen consumption rate (OCR). A simultaneous decrease in extracellular acidification rate (ECAR) was observed. Furthermore, in the absence of glucose, OCR did not increase in response to butyrate. These results lead us to believe that butyrate itself was not responsible for the observed increase in OCR, but, instead, butyrate stimulated pyruvate flux into mitochondria. Indeed, blocking of the mitochondrial pyruvate carrier prevented a butyrate-induced increase in oxygen consumption. Taken together, our results indicate that butyrate itself is not oxidized in cultured cells but instead alters pyruvate flux and induces lipid accumulation.

Effects of sodium butyrate supplementation on inflammation, gut microbiota, and short-chain fatty acids in Helicobacter pylori-infected mice

BACKGROUND

Inflammation induced by Helicobacter pylori (H. pylori) infection is the basis for the pathogenesis of H. pylori. Butyric acid, a diet-related microbial-associated metabolite, is connected to inflammation, metabolic syndrome, and other diseases. Several studies have indicated the effects of sodium butyrate (SB) against bacteria; however, the effects of SB on the main virulence factors of H. pylori, H. pylori-induced inflammation, and gut microbiota composition remain unclear.

MATERIALS AND METHODS

SB was supplemented in H. pylori coculture and administered to mice infected with H. pylori. The effects of SB intake on inflammation, gut microbiota composition, and short-chain fatty acids (SCFAs) in H. pylori-infected mice were assessed.

RESULTS

The in vitro experiments demonstrated that SB not only inhibited the growth of H. pylori but also decreased the mRNA expression of CagA and VacA. SB intake reduced the production of virulence factors in H. pylori-infected mice, inhibited the IκBα/NF-κB pathway by reducing the expression of Toll-like receptors (TLRs), and reduced the production of TNF-α and IL-8. Further analysis demonstrated that H. pylori infection altered the relative abundance of the intestinal microbial community in mice. The level of SCFAs in the feces of H. pylori-infected mice was changed, although the intake of SB did not obviously change the level of SCFAs.

CONCLUSIONS

Our study showed that SB may decrease H. pylori-induced inflammation by inhibiting the viability and virulence of H. pylori and may reduce inflammation in association with the gut microbiota in H. pylori-infected mice. This study may provide novel insights into the mechanisms by which SB, a diet-related microbial-associated metabolite, affects H. pylori-induced disease development.