Sodium butyrate arrests pancreato-hepatic synchronous uric acid and lipid dysmetabolism in high fat diet fed Wistar rats

Isolation and identification of uric acid-dependent Aciduricibacillus chroicocephali gen. nov., sp. nov. from seagull feces and implications for hyperuricemia treatment

Hyperuricemia has become the second most prevalent metabolic disease after diabetes, but the limitations of urate-lowering treatment (ULT) drugs and patient nonadherence make ULT far less successful. Thus, more ULT approaches urgently need to be explored. Uric acid-degrading bacteria have potential application value in ULT. In this study, we isolated 44XBT, a uric acid-degrading bacterium, from black-headed gull (Chroicocephalus ridibundus) feces. Using a polyphasic taxonomic approach, strain 44XBT was identified as a novel genus within the family Bacillaceae; subsequently, the name Aciduricibacillus chroicocephali was proposed. Strain 44XBT had a unique uric acid-dependent phenotype and utilized uric acid and allantoin as the sole carbon and nitrogen sources, but not common carbon sources or complex media. In the genome, multiple copies of genes involved in uric acid metabolic pathway (pucL, pucM, uraD, and allB) were found. Six copies of pucL (encoding urate oxidase) were detected. Of these, five pucL copies were in a tandem arrangement and shared 70.42%-99.70% amino acid identity. In vivo experiments revealed that 44XBT reduced serum uric acid levels and attenuated kidney damage in hyperuricemic mice through uric acid catalysis in the gut and gut microbiota remodeling. In conclusion, our findings discover a strain for studying bacterial uric acid metabolism and may provide valuable insights into ULT.

IMPORTANCE

The increasing disease burden of hyperuricemia highlights the need for new therapeutic drugs and treatment strategies. Our study describes the developmental and application values of natural uric acid-degrading bacteria found in the gut of birds and broadened the source of bacteria with potential therapeutic value. Furthermore, the special physiology characteristics and genomic features of strain 44XBT are valuable for further study.

Mechanisms of epigallocatechin gallate (EGCG) in ameliorating hyperuricemia: insights into gut microbiota and intestinal function in a mouse model

Epigallocatechin gallate (EGCG), a prominent bioactive compound found in tea, offers numerous health benefits. Previous studies have highlighted its potential in mitigating hyperuricemia. In this study, hyperuricemic mice induced by potassium oxonate (PO) were treated with EGCG or the anti-hyperuricemia medication allopurinol (AP) to investigate the mechanisms underlying their anti-hyperuricemic effects. The results demonstrated that both EGCG and AP significantly reduced serum uric acid (UA) levels. Further analysis revealed that EGCG promoted the expression of UA secretion transporter genes (Oat1 and Oct1) while inhibiting the expression of UA reabsorption transporter genes (Urat1 and Glut9) in the kidney. By 16S rDNA sequencing, EGCG, but not AP, was found to alter the composition of the gut microbiota. Notably, EGCG induced significant changes in the relative abundance of specific bacteria such as Lactobacillus, Faecalibaculum, and Bifidobacterium, which displayed high correlations with serum UA levels and UA-related gene expression. Metabolomic analysis suggested that EGCG-induced modifications in bacterial metabolites might contribute to the alleviation of hyperuricemia. Transcriptomic analysis of the intestinal epithelium identifies 191 differentially expressed genes (DEGs) in EGCG-treated mice, including 8 purine-related genes. This study elucidates the anti-hyperuricemic mechanisms of EGCG, particularly its influence on the gut microbiota and gene expression in the intestinal epithelium.

Assessing the causal relationships of gut microbial genera with hyperuricemia and gout using two-sample Mendelian randomization

BACKGROUND AND AIMS

The causal relationship between gut microbiota and gout and hyperuricemia (HUA) has not been clarified. The objective of this research was to evaluate the potential causal effects of gut microbiota on HUA and gout using a two-sample Mendelian randomization (MR) approach.

METHODS AND RESULTS

Genetic instruments were selected using summary statistics from genome-wide association studies (GWASs) comprising a substantial number of individuals, including 18,473 participants for gut microbiome, 288,649 for serum urate (SU), and 763,813 for gout. Two-sample MR analyses were performed to determine the possible causal associations of gut microbial genera with the risk of HUA and gout using the inverse-variance weighted (IVW) method, and robustness of the results was confirmed by several sensitivity analyses. A reverse MR analysis was conducted on the bacterial taxa that were identified in forward MR analysis. Based on the results of MR analyses, Escherichia-Shigella (OR = 1.05; 95% CI, 1.01-1.08; P = 0.009) exhibited a positive association with SU levels, while Lachnospiraceae NC2004 group (OR = 0.95; 95% CI, 0.92-0.98; P = 0.001) and Family XIII AD3011 group (OR = 0.94; 95% CI, 0.90-0.99; P = 0.015) were associated with a reduced HUA risk. Moreover, Coprococcus 3 (OR = 1.17, 95% CI: 1.01-1.34, P = 0.031) was causally associated with a higher gout risk. In reverse MR analysis, no causal relationships were identified between these bacterial genera and HUA or gout.

CONCLUSION

This study provides evidence for a causal association between gut microbial genera and HUA or gout, and further investigations of the underlying mechanism are warranted.

Dietary sodium acetate and sodium butyrate attenuate intestinal damage and improve lipid metabolism in juvenile largemouth bass (Micropterus salmoides) fed a high carbohydrate diet by reducing endoplasmic reticulum stress

High-carbohydrate (HC) diets decrease the intestinal levels of sodium acetate (SA) and sodium butyrate (SB) and impair the gut health of largemouth bass; however, SA and SB have been shown to enhance immunity and improve intestinal health in farmed animals. Thus, the present study was to investigate the effects of dietary SA and SB on HC diet-induced intestinal injury and the potential mechanisms in juvenile largemouth bass. The experiment set five isonitrogenous and isolipidic diets, including a low-carbohydrate diet (9% starch) (LC), a high carbohydrate diet (18% starch) (HC), and the HC diet supplemented with 2 g/kg SA (HCSA), 2 g/kg SB (HCSB) or a combination of 1 g/kg SA and 1 g/kg SB (HCSASB). The feeding experiment was conducted for 8 weeks. A total of 525 juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were used. The results showed that dietary SA and SB improved the weight gain rate and specific growth rate (P < 0.05) and ameliorated serum parameters (alkaline phosphatase, acid phosphatase, glutamate transaminase, and glutamic oxaloacetic transaminase) (P < 0.05). And, importantly, dietary SA and SB repaired the intestinal barrier by increasing the expression levels of zonula occludens-1, occludin, and claudin-7 (P < 0.05), reduced HC-induced intestinal damage, and alleviated intestinal inflammation and cell apoptosis by attenuating HC-induced intestinal endoplasmic reticulum stress (P < 0.05). Further results revealed that dietary SA and SB reduced HC-induced intestinal fat deposition by inhibiting adipogenesis and promoting lipolysis (P < 0.05). In summary, this study demonstrated that dietary SA and SB attenuated HC-induced intestinal damage and reduced excessive intestinal fat deposition in largemouth bass.

Coated sodium butyrate ameliorates high-energy and low-protein diet induced hepatic dysfunction via modulating mitochondrial dynamics, autophagy and apoptosis in laying hens

BACKGROUND

Fatty liver hemorrhagic syndrome (FLHS), a fatty liver disease in laying hens, poses a grave threat to the layer industry, stemming from its ability to trigger an alarming plummet in egg production and usher in acute mortality among laying hens. Increasing evidence suggests that the onset and progression of fatty liver was closely related to mitochondria dysfunction. Sodium butyrate was demonstrated to modulate hepatic lipid metabolism, alleviate oxidative stress and improve mitochondrial dysfunction in vitro and mice models. Nevertheless, there is limited existing research on coated sodium butyrate (CSB) to prevent FLHS in laying hens, and whether and how CSB exerts the anti-FLHS effect still needs to be explored. In this experiment, the FLHS model was induced by administering a high-energy low-protein (HELP) diet in laying hens. The objective was to investigate the effects of CSB on alleviating FLHS with a focus on the role of CSB in modulating mitochondrial function.

METHODS

A total of 288 healthy 28-week-old Huafeng laying hens were arbitrarily allocated into 4 groups with 6 replicates each, namely, the CON group (normal diet), HELP group (HELP diet), CH500 group (500 mg/kg CSB added to HELP diet) and CH750 group (750 mg/kg CSB added to HELP diet). The duration of the trial encompassed a period of 10 weeks.

RESULTS

The result revealed that CSB ameliorated the HELP-induced FLHS by improving hepatic steatosis and pathological damage, reducing the gene levels of fatty acid synthesis, and promoting the mRNA levels of key enzymes of fatty acid catabolism. CSB reduced oxidative stress induced by the HELP diet, upregulated the activity of GSH-Px and SOD, and decreased the content of MDA and ROS. CSB also mitigated the HELP diet-induced inflammatory response by blocking TNF-α, IL-1β, and F4/80. In addition, dietary CSB supplementation attenuated HELP-induced activation of the mitochondrial unfolded protein response (UPRmt), mitochondrial damage, and decline of ATPase activity. HELP diet decreased the autophagosome formation, and downregulated LC3B but upregulated p62 protein expression, which CSB administration reversed. CSB reduced HELP-induced apoptosis, as indicated by decreases in the Bax/Bcl-2, Caspase-9, Caspase-3, and Cyt C expression levels.

CONCLUSIONS

Dietary CSB could ameliorate HELP diet-induced hepatic dysfunction via modulating mitochondrial dynamics, autophagy, and apoptosis in laying hens. Consequently, CSB, as a feed additive, exhibited the capacity to prevent FLHS by modulating autophagy and lipid metabolism.

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.

Coffee Leaf Tea Extracts Improve Hyperuricemia Nephropathy and Its Associated Negative Effect in Gut Microbiota and Amino Acid Metabolism in Rats

Hyperuricemia nephropathy (HN) is a metabolic disease characterized by tubular damage, tubulointerstitial fibrosis, and uric acid kidney stones and has been demonstrated to be associated with hyperuricemia. Coffee leaf tea is drunk as a functional beverage. However, its prevention effects on HN remain to be explored. This study showed that coffee leaf tea extracts (TE) contain 19 polyphenols, with a total content of 550.15 ± 27.58 mg GAE/g. TE decreased serum uric acid levels via inhibiting XOD activities and modulating the expression of urate transporters (GLUT9, OAT3, and ABCG2) in HN rats. TE prevented HN-induced liver and kidney damage and attenuated renal fibrosis. Moreover, it upregulated the abundance of SCFA-producing bacteria (Phascolarctobacterium, Alloprevotella, and Butyricicoccus) in the gut and reversed the amino acid-related metabolism disorder caused by HN. TE also decreased the circulating LPS and d-lactate levels and increased the fecal SCFA levels. This study supported the preliminary and indicative effect of coffee leaf tea in the prevention of hyperuricemia and HN.

Glucoregulatory effect of butyrate is associated with elevated circulating VEGF and reduced cardiac lactate in high fructose fed rats

Background

High fructose diet has been linked with impaired body metabolism and cardiovascular diseases. Sodium butyrate (NaB) was documented to improve glucoregulation and cardiometabolic problems associated with high fructose diet (HFrD) but the mechanisms behind it are unclear. As a result, the purpose of this study was to look into the effects of NaB on VEGF and cardiac lactate in HFrD-induced dysmetabolism.

Methods

Twenty male Wistar rats of weight 130-140 g were assigned randomly after a week of acclimation into four groups: Control diet (CTR), High fructose drink (HFrD); 10 % (w/v), NaB (200 mg/kg bw), and HFrD + NaB (200 mg/kg bw). The animals were induced to be unconscious with 50 mg/kg of pentobarbital sodium intraperitoneally, blood samples were taken via cardiac puncture and cardiac tissue homogenates were obtained for Fasting Blood Sugar (FBS) and plasma insulin, cardiac glycogen, plasma and cardiac glycogen synthase, plasma and cardiac nitric oxide as well as vascular endothelial growth factor (VEGF).

Result

HFrD resulted in statistical elevation body and cardiac weight, plasma glucose, plasma insulin, cardiac lactate, glycogen and decreased nitric oxide level (NO) when compared with the control group. Administration of NaB reduced cardiac weight, blood glucose, plasma insulin, cardiac lactate while nitric oxide and glycogen increased (P < 0.05). NaB increased plasma glycogen synthase in normal rats, plasma and cardiac circulating VEGF in HFrD administered rats (P < 0.05) while no change was produced in plasma and cardiac glycogen synthase level of HFrD treated rats.

Conclusion

Sodium butyrate improves glucoregulation by reducing cardiac lactate and increasing circulating VEGF in HFrD-treated rats.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Cardiac angiogenesis enhances by activating Mir-126 and related target proteins in type 2 diabetic rats: Rescue combination effect of Sodium butyrate and voluntary exercise therapy

Objective

type 2 diabetes, metabolic disorder, is one of the main risk factors for cardiovascular disease, leading to angiogenesis injury. The present study wanted to discover the effect of sodium butyrate (NaB) and voluntary exercise, alone or together, on miR-126 and related proteins in rats with type 2 diabetes.

Methods

thirty-five male Wistar rats (200-250 g) were randomly divided into five groups: control, diabetes, diabetes-NaB, diabetes-exercise, and diabetes-NaB-exercise. Type 2 diabetes was induced by intraperitoneal injection of streptozotocin (35 mg/kg) and high-fat diet. The rats were then administrated NaB (200 mg/kg. ip) or were subjected to voluntary exercise, or combined NaB and voluntary exercise for 8 weeks. MiR-126 expression in the cardiac tissue was determined by real-time PCR, and the SPRED-1 and RAF proteins expression levels were measured by western blot.

Results

NaB and voluntary exercise up-regulated cardiac miR-126 and RAF expression levels and down-regulated SPRED-1 in cardiac tissue of type 2 diabetic rats. Moreover, the combination of NaB and voluntary exercise amplified their effects on those parameters. Both NaB and voluntary exercise or together markedly modulated serum glucose and HbA1c.

Conclusion

The present findings demonstrated that NaB combined with exercise could improve cardiac angiogenesis by increasing miR-126 and affecting related proteins. Thus, NaB together with voluntary exercise might be a promising intervention for the treatment and prevention of type 2 diabetes.

Dietary Coated Sodium Butyrate Ameliorates Hepatic Lipid Accumulation and Inflammation via Enhancing Antioxidative Function in Post-Peaking Laying Hens

During the aging process of laying hens, hepatic oxidative stress damage and lipid accumulation are prone to occur, leading to the deterioration of egg quality and a decline in production properties. This research was designed to explore the effects of different levels of coated sodium butyrate (CSB) addition on oxidation resistance, inflammatory reaction, lipid metabolism and hepatic oxidative damage-related gene expression in aged laying hens. A total of 720 healthy 52 weeks old Huafeng laying hens were arbitrarily divided into 5 groups of 6 replicates with 24 birds each and fed a basal diet supplemented with 0, 250, 500, 750 and 1000 mg/kg CSB for 8 weeks, respectively. The CSB quadratically upgraded GSH-Px activities and downgraded MDA content in the liver and serum. The LDL-C, NEFA and TG contents decreased quadratically in CSB groups and significantly reduced the fatty vacuoles as well as the formation of fat granules in the liver (p < 0.05). Meanwhile, the CSB quadratically upregulated the gene expression of IL-10, Nrf2 and HO1, but downregulated the gene expression of IFN-γ, TNF-α and Keap1 in a quadratic manner (p < 0.05). Moreover, the CSB quadratically degraded the mRNA level of fatty acid synthesis but increased the gene level of key enzymes of fatty acid catabolism (p < 0.05). In conclusion, dietary CSB supplementation has a favorable effect in protecting against liver injury and alleviating lipid accumulation and inflammation by enhancing hepatic antioxidative function in aged laying hens.

Sodium butyrate and voluntary exercise through activating VEGF-A downstream signaling pathway improve heart angiogenesis in type 2 diabetes

BACKGROUND

Inadequate angiogenesis in patients with type 2 diabetic heart could result in deprived collateral formation. Herein, we aimed to investigate the effects of sodium butyrate (NaB) along with voluntary exercise simultaneously on the mechanisms acting on cardiac angiogenesis.

MATERIALS AND METHODS

Animals were divided into the following five groups: control (Con), diabetic rats (Dia), diabetic rats treated with NaB (200 mg/kg, i.p.) (Dia-NaB), diabetic rats receiving voluntary exercise (Dia-Exe), and diabetic rats treated with NaB and exercise simultaneously (Dia-NaB-Exe). After an eight-week duration, NO metabolites levels were measured using Griess method, the VEGF-A and VEGFR2 expressions was examined by PCR, the expressions of VEGF-A and VEGFR2 proteins was investigated by western blot, and ELISA method was used for Akt, ERK1/2 expression.

RESULTS

Cardiac VEGF-A and VEGFR2 expressions were higher in the Dia-Exe and Dia-NaB-Exe groups compared to the Dia group. However, a combination of exercise and NaB enhanced the VEGF-A expression in cardiac tissue compared to the Dia-NaB and Dai-Exe groups. Heart NOx concentration was higher in the treated groups compared to the Dia group. The expression of cardiac Akt levels increased in both the Dia-Exe and Dia-NaB-Exe groups compared to the Dia groups. In addition, cardiac ERK1/2 expression was found to be higher in the Dia-NaB-Exe group compared to the Dia group.

CONCLUSION

The findings of this study showed the therapeutic potential of a novel combination therapy of sodium butyrate and voluntary exercise in improving cardiac angiogenesis with the enhanced involvement mechanism in high fat/STZ-induced type 2 diabetic rats.

Butyrate and obesity: Current research status and future prospect

Over the past few decades, increasing prevalence of obesity caused an enormous medical, social, and economic burden. As the sixth most important risk factor contributing to the overall burden of disease worldwide, obesity not only directly harms the human body, but also leads to many chronic diseases such as diabetes, cardiovascular diseases (CVD), nonalcoholic fatty liver disease (NAFLD), and mental illness. Weight loss is still one of the most effective strategies against obesity and related disorders. Recently, the link between intestinal microflora and metabolic health has been constantly established. Butyrate, a four-carbon short-chain fatty acid, is a major metabolite of the gut microbiota that has many beneficial effects on metabolic health. The anti-obesity activity of butyrate has been demonstrated, but its mechanisms of action have not been fully described. This review summarizes current knowledge of butyrate, including its production, absorption, distribution, metabolism, and the effect and mechanisms involved in weight loss and obesity-related diseases. The aim was to contribute to and advance our understanding of butyrate and its role in obesity. Further exploration of butyrate and its pathway may help to identify new anti-obesity.

Recent advances and potentiality of postbiotics in the food industry: Composition, inactivation methods, current applications in metabolic syndrome, and future trends

Postbiotics are defined as "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host". Postbiotics have unique advantages over probiotics, such as stability, safety, and wide application. Although postbiotics are research hotspots, the research on them is still very limited. This review provides comprehensive information on the scope of postbiotics, the preparation methods of inanimate microorganisms, and the application and mechanisms of postbiotics in metabolic syndrome (MetS). Furthermore, the application trends of postbiotics in the food industry are reviewed. It was found that postbiotics mainly include inactivated microorganisms, microbial lysates, cell components, and metabolites. Thermal treatments are the main methods to prepare inanimate microorganisms as postbiotics, while non-thermal treatments, such as ionizing radiation, ultraviolet light, ultrasound, and supercritical CO2, show great potential in postbiotic preparation. Postbiotics could ameliorate MetS through multiple pathways including the modulation of gut microbiota, the enhancement of intestinal barrier, the regulation of inflammation and immunity, and the modulation of hormone homeostasis. Additionally, postbiotics have great potential in the food industry as functional food supplements, food quality improvers, and food preservatives. In addition, the SWOT analyses showed that the development of postbiotics in the food industry exists both opportunities and challenges.

Influence of Dietary Inulin on Fecal Microbiota, Cardiometabolic Risk Factors, Eicosanoids, and Oxidative Stress in Rats Fed a High-Fat Diet

The present study examined the influence of inulin on fecal microbiota, cardiometabolic risk factors, eicosanoids, and oxidative stress in rats on a high-fat (HF) diet. Thirty-six male Wistar-Kyoto rats were divided into three dietary groups: standard diet, HF diet, and HF diet + Inulin diet. After 10 weeks, the HF + Inulin diet promoted high dominance of a few bacterial genera including Blautia and Olsenella in feces while reducing richness, diversity, and rarity compared to the HF diet. These changes in fecal microbiota were accompanied by an increased amount of propionic acid in feces. The HF + Inulin diet decreased cardiometabolic risk factors, decreased the amount of the eicosanoids 11(12)-EET and 15-HETrE in the liver, and decreased oxidative stress in blood compared to the HF diet. In conclusion, increasing consumption of inulin may be a useful nutritional strategy to protect against the onset of obesity and its associated metabolic abnormalities by means of modulation of gut microbiota.

Interventions for non-alcoholic liver disease: a gut microbial metabolites perspective

Over the past two decades, non-alcoholic fatty liver disease (NAFLD) has become a leading burden of hepatocellular carcinoma and liver transplantation. Although the exact pathogenesis of NAFLD has not been fully elucidated, recent hypotheses placed more emphasis on the crucial role of the gut microbiome and its derivatives. Reportedly, microbial metabolites such as short-chain fatty acids, amino acid metabolites (indole and its derivatives), bile acids (BAs), trimethylamine N-oxide (TMAO), and endogenous ethanol exhibit sophisticated bioactive properties. These molecules regulate host lipid, glucose, and BAs metabolic homeostasis via modulating nutrient absorption, energy expenditure, inflammation, and the neuroendocrine axis. Consequently, a broad range of research has studied the therapeutic effects of microbiota-derived metabolites. In this review, we explore the interaction of microbial products and NAFLD. We also discuss the regulatory role of existing NAFLD therapies on metabolite levels and investigate the potential of targeting those metabolites to relieve NAFLD.

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.

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

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

Diet-Related Changes of Short-Chain Fatty Acids in Blood and Feces in Obesity and Metabolic Syndrome

Obesity-related illnesses are one of the leading causes of death worldwide. Metabolic syndrome has been associated with numerous health issues. Short-chain fatty acids (SCFAs) have been shown to have multiple effects throughout the body, both directly as well as through specific G protein-coupled receptors. The main SCFAs produced by the gut microbiota are acetate, propionate, and butyrate, which are absorbed in varying degrees from the large intestine, with some acting mainly locally and others systemically. Diet has the potential to influence the gut microbial composition, as well as the type and amount of SCFAs produced. High fiber-containing foods and supplements increase the production of SCFAs and SCFA-producing bacteria in the gut and have been shown to have bodyweight-lowering effects. Dietary supplements, which increase SCFA production, could open the way for novel approaches to weight loss interventions. The aim of this review is to analyze the variations of fecal and blood SCFAs in obesity and metabolic syndrome through a systematic search and analysis of existing literature.

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.

Probiotics, bioactive compounds and dietary patterns for the effective management of hyperuricemia: a review

Hyperuricemia is closely linked with an increased risk of developing hypertension, diabetes, renal failure and other metabolic syndromes. Probiotics, bioactive compounds and dietary patterns are safe cost-efficient ways to control hyperuricemia, whereas comprehensive reviews of their anti-hyperuricemic mechanisms are limited. This review summarizes the roles of probiotics, bioactive compounds and dietary patterns in treating hyperuricemia and critically reviews the possible mechanisms by which these interventions exert their activities. The dietary patterns are closely related to the occurrence of hyperuricemia through the indirect action of gut microbiota or the direct effects of host purine metabolism. The Mediterranean and Dietary Approaches to Stop Hypertension diets help reduce serum uric acid concentrations and thus prevent hyperuricemia. Meanwhile, probiotics alleviate hyperuricemia by ways of absorbing purine, restoring gut microbiota dysbiosis and inhibiting xanthine oxidase (XO) activity. Bioactive compounds such as polyphenols, peptides and alkaloids exert various anti-hyperuricemic effects, by regulating urate transporters, blocking the active sites of XO and inhibiting the toll-like receptor 4/nuclear factor kappa B signaling pathway and NOD-, LRR- and pyrin domain-containing protein 3 signaling pathway. This review will assist people with hyperuricemia to adopt a healthy diet and contribute to the application of natural products with anti-hyperuricemic activity.

Acetate-mediated-obestatin modulation attenuates adipose-hepatic dysmetabolism in high fat diet-induced obese rat model

PURPOSE

Approximately 650 million of world adult population is affected by obesity, which is characterized by adipose and hepatic metabolic dysfunction. Short chain fatty acids (SCFAs) have been linked to improved metabolic profile. However, the effect of SCFAs, particularly acetate on adipose-hepatic dysfunction is unclear. Therefore, the present study investigated the role of acetate on adipose-hepatic metabolic dysfunction and the possible involvement of obestatin in high fat diet-induced obese Wistar rats.

METHODS

Adult male Wistar rats (160-190 g) were allotted into groups (n = 6/group): Control, acetate-treated, obese and obese + acetate-treated groups received vehicle (distilled water), sodium acetate (200 mg/kg), 40% HFD and 40% HFD plus sodium acetate respectively. The administration lasted for 12 weeks.

RESULTS

HFD caused increased body weight gain and visceral adiposity, insulin resistance, hyperinsulinemia and increased pancreatic-β cell function and plasma/hepatic triglyceride and total cholesterol as well as decreased adipose triglyceride and total cholesterol, increased plasma, adipose, and hepatic malondialdehyde, TNF-α, uric acid, lactate production and plasma/adipose but not gamma-glutamyl transferase and decreased plasma, adipose, and hepatic nitric oxide, glucose-6-phosphate dehydrogenase (G6PD), glutathione (GSH) and obestatin concentration compared to the control group. Notwithstanding, treatment with acetate attenuated the alterations.

CONCLUSIONS

The results demonstrate that high fat diet-induced obesity is characterized with adipose and hepatic lipid dysmetabolism, which is associated with obestatin suppression. Findings also suggest that acetate provide protection against adipose and hepatic metabolic perturbations by restoring obestatin as well as G6PD/GSH-dependent antioxidant system.

Chlorogenic acid supplementation ameliorates hyperuricemia, relieves renal inflammation, and modulates intestinal homeostasis

Hyperuricemia (HUA) is induced by abnormal purine metabolism and elevated serum uric acid (UA) concentrations, and it is often accompanied by inflammatory responses and intestinal disorders. This study aims to assess the protective effects of chlorogenic acid (CGA) on HUA in mice. CGA or allopurinol was given to mice with HUA induced by hypoxanthine and potassium oxonate. CGA lowered the levels of UA, blood urea nitrogen (BUN), creatinine (CR), AST, and ALT; inhibited xanthine oxidase (XOD) activity; and downregulated the mRNA expression of UA secretory proteins in HUA mice. Moreover, CGA significantly reduced serum lipopolysaccharides (LPS) levels and the mRNA expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, NOD-like receptor superfamily pyrin domain containing 3 (NLRP3), and caspase-1, and it inhibited the activation of the toll-like receptor 4/myeloid differentiation factor 88/nuclear factor kappa B (TLR4/MyD88/NF-κB) signaling pathway in the kidney, resulting in inflammation relief in HUA mice. In addition, CGA treatment increased the production of fecal short-chain fatty acids (SCFAs) in HUA mice. Additional investigations showed that CGA significantly lowered the mRNA expression of ileal IL-1β and IL-6, and it increased the mRNA expression of intestinal tight junction proteins (zonula occludens-1 (ZO-1) and occludin). Also, CGA increased the relative abundance of SCFA-producing bacteria, including Bacteroides, Prevotellaceae UGC-001, and Butyricimonas, and it reversed the purine metabolism and glutamate metabolism functions of gut microbiota. In conclusion, CGA may be a potential candidate for relieving the symptoms of HUA and regulating its associated inflammatory responses and intestinal homeostasis.