Sodium butyrate ameliorates diabetic retinopathy in mice via the regulation of gut microbiota and related short-chain fatty acids

Gut microbiota Lactobacillus johnsonii alleviates hyperuricemia by modulating intestinal urate and gut microbiota-derived butyrate

BACKGROUND

Gut microbiota are important for uric acid (UA) metabolism within hyperuricemia (HUA); however, the underlying mechanisms of how the gut microbiota regulate intestinal UA metabolism remain unclear. This study aimed to explore the function of the intestine in HUA and to further reveal the possible mechanism.

METHODS

We conducted gut microbiota depletion to validate the role of gut microbiota in UA metabolism. A mouse model of HUA was established, and the gut microbiota and microbiome-derived metabolites were analyzed via 16S RNA gene sequencing and metabolomics analysis. The mechanism of the gut microbiota in HUA was elucidated by in vivo and in vitro experiments.

RESULTS

Antibiotic treatment elevated serum UA, disturbed purine metabolism, and decreased the relative abundance of Lactobacillus. HUA mice had a lower relative abundance of Lactobacillus johnsonii (L. johnsonii) and decreased gut butyrate concentration. Supplementation of L. johnsonii significantly reduces serum UA in hyperuricemia mice by preventing UA synthesis and promoting the excretion of gut purine metabolites. In addition, L. johnsonii enhanced intestinal UA excretion by heightening the urate transporter ABCG2 (adenosine triphosphate-binding cassette transporter, subfamily G, member 2) expression, and increasing the levels of butyrate, which upregulated ABCG2 expression via the Wnt5a/b/β-catenin signaling pathway.

CONCLUSION

Our results suggest that gut microbiota and microbiota-derived metabolites directly regulate gut UA metabolism, highlighting potential applications in the treatment of diet-induced HUA by targeting gut microbiota and its metabolites.

Mitigating T-2 toxin toxicity in Quail: The protective power of sodium butyrate

As one of the most common worldwide contaminants in agricultural production, the T-2 mycotoxin is commonly found in moldy feed and its raw materials. It can slow the growth and suppress the immune function of farm animals, resulting in reduced economic benefits. As a feed additive, sodium butyrate can enhance immune function. However, the toxicological effects of the T-2 toxin on the spleen, thymus, and bursa of Fabricius and the protective mechanism of sodium butyrate against the T-2 toxin in quails are not known. In this study, 1-day-old Korean quails were fed either with T-2 toxin (0.9 mg/kg) spiked food or with spiked food and sodium butyrate (500 mg/kg) as an antagonist, to construct an experimental animal model. Histopathological changes in the immune organs (spleen, thymus, and bursa of Fabricius) of the quails under sub-chronic toxicity of T-2 toxin were observed after 28 days of continuous treatment. The effects of the T-2 toxin and sodium butyrate on the fibrosis of the immune organs were investigated by MASSON staining and fibrosis gene expression, while the effects of the T-2 toxin and sodium butyrate on apoptosis of the immune organs were investigated by TUNEL assay. The expression of apoptosis-related genes was also measured to evaluate the effects of the T-2 toxin on pathological damage, fibrosis, apoptosis, and CYP450 homeostasis while the antagonistic effect of sodium butyrate on the quail immune organs was also measured. Results showed that sodium butyrate could effectively alleviate pathological damage, fibrosis, apoptosis, abnormal activation of the heterologous nuclear receptor pathway, and the disruption of CYP450 homeostasis induced by the T-2 toxin in quail immune organs.

Vaccinium myrtillus L. ameliorates diabetic nephropathy via modulating metabolites and gut microbiota in rats

Introduction

Diabetic nephropathy (DN), one of the serious complications in the diabetes, has a high mortality in the diabetic patients. Bilberry (Vaccinium myrtillus L.) have received much attention for their health benefits in alleviating metabolic diseases, which are rich in anthocyanins. However, the anti-DN ability of bilberry has not been fully studied. The aim of this study was to investigate the effect and mechanism of Vaccinium myrtillus L. extract (VCE) on diabetic nephropathy in vivo and in vitro.

Methods

Streptozocin (STZ) combined with high fat induced DN model was established in rats. Biochemical indicators, histopathology, 16s third generation sequencing and serum metabolomics were used to evaluate the effects of VCE on DN. Subsequently, a cell model of advanced glycation end products (AGEs) induced podocyte injury was established to verify which compounds in VCE played the main anti-diabetic nephropathy function and the mechanism of action. Finally, in vitro experiments were conducted to verify the effect of characteristic metabolites screened by serum metabolomics on improving diabetic nephropathy.

Results

Insulin resistance index, lipid metabolism, oxidative stress and inflammatory response indexes of DN rats were significantly improved after 8 weeks of VCE treatment. In addition, intake of VCE modulates gut microbiota composition and reverses the abundance of Lactobacillus, Bifidobacterium and Ruminococcus. Supplementation with VCE altered serum metabolite levels, including uridine and phenylacetylglycine. Pretreatment with VCE and its anthocyanins inhibited the expression of LDH, IL-6 and TNF-α, reduced the levels of p38-MAPK, IĸBα, IKKβ, and NF-κB in podocyte cells. In addition, pretreatment with serum metabolite uridine also reduced the expression of LDH and mitochondrial ROS, and inhibited cell apoptosis.

Conclusion

Our findings suggest that the improvement of gut microbiota and metabolic function were related to the anti-DN potential of VCE, and the underlying mechanism may be related to the inhibition of MAPK/NF-κB signaling pathway.

Sodium butyrate alleviates spinal cord injury via inhibition of NLRP3/Caspase-1/GSDMD-mediated pyroptosis

NOD-like receptor protein 3 (NLRP3)/cysteinyl aspartate-specific proteinase 1 (Caspase-1)/gasdermin D (GSDMD)-mediated pyroptosis is linked to spinal cord injury (SCI) pathogenesis. The levels of short-chain fatty acids (SCFAs), especially butyric acid, are significantly altered after SCI. Sodium butyrate (NaB) has anti-inflammatory effects on SCI; however, its effect on pyroptosis is unknown. The aim of this study was to determine the role of NaB in SCI functional recovery and its effect on NLRP3/Caspase-1/GSDMD-mediated pyroptosis. SCI model rats were established using aneurysm clips. After SCI, rats were administered NaB (300 mg/kg) via gavage. SCFAs in faeces were measured using gas chromatography-mass spectrometry. Motor function recovery was assessed using cylinder rearing and grooming tests. Histopathological analysis was performed using haematoxylin-eosin staining, transmission electron microscopy, and terminal deoxynucleotidyl transferase dUTP nick-end labelling. The expression of proteins associated with pyroptosis signalling pathways was analysed using enzyme-linked immunosorbent assay, western blotting, and immunohistochemistry. SCFAs levels, particularly butyric acid, significantly decreased after SCI. NaB treatment promoted forelimb motor function recovery and attenuated pathological SCI. NaB also decreased spinal pro-inflammatory factors (interleukin-18 and interleukin-1β) and downregulated pyroptosis-related proteins, including NLRP3, apoptosis-associated speck-like protein, Caspase-1, and GSDMD. NaB inhibits NLRP3/Caspase-1/GSDMD-mediated neuronal pyroptosis and inflammation, exerting protective and therapeutic effects in SCI, suggesting NaB as an effective SCI treatment.

Advances in molecular epidemiology of diabetic retinopathy: from genomics to gut microbiomics

Diabetic retinopathy (DR) remains a prevalent complication of diabetes mellitus and a leading cause of blindness worldwide. The growing global diabetic population underscores the urgency to deepen our understanding of DR pathogenesis and develop effective prevention strategies. This review synthesizes recent advancements in molecular epidemiology, spanning genomics, epigenomics, transcriptomics, proteomics, metabolomics, and gut microbiomics, elucidating genetic underpinnings, epigenetic modifications, transcriptional alterations, protein biomarkers, metabolic disruptions, and gut microbiota dysbiosis associated with DR. Highlighted are key findings from genome-wide association studies (GWAS), Mendelian randomization (MR) studies, candidate gene association studies, and advancements in epigenetic mechanisms, revealing intricate disease pathways and potential therapeutic targets. Additionally, insights into altered metabolic profiles and gut microbiota compositions in DR underscore their emerging roles in disease progression and complications. Challenges and future directions in molecular epidemiological research are discussed to accelerate the translation of these findings into clinical applications for personalized DR management. The integration of multi-omics research findings may provide novel perspectives for facilitating rapid and accurate disease diagnosis, enabling dynamic disease monitoring, and advancing targeted therapeutic strategies.

Short-Chain Fatty Acids and the Gut-Retina Connection: A Systematic Review

The interplay between gut microbiota and retinal health, known as the gut--retina axis, has gained increasing attention in recent years. Short-chain fatty acids (SCFAs), metabolites produced by gut microbiota, have been identified as key mediators of gut-retina communication. This systematic review explores the role of SCFAs in retinal health and their potential impact on the development and progression of retinal diseases, such as diabetic retinopathy (DR), age-related macular degeneration (AMD), and glaucoma. A literature search was conducted across multiple databases, including PubMed, Google Scholar, and Science Direct, to identify studies published between 2014 and December 2024. Studies were included if they investigated the effects of SCFAs on retinal structure, function, or disease pathogenesis in animal models or human subjects. The review included 10 original articles spanning both preclinical and clinical studies. Evidence suggests that SCFAs play a crucial role in maintaining retinal homeostasis through anti-inflammatory and neuroprotective mechanisms. Dysbiosis of the gut microbiota, leading to altered SCFA production, was associated with increased retinal inflammation, oxidative stress, and vascular dysfunction. Furthermore, reduced SCFA levels were linked to the progression of retinal diseases, such as diabetic retinopathy and age-related macular degeneration. Modulation of gut microbiota and SCFA levels through dietary interventions or probiotics may represent a novel therapeutic strategy for preventing or managing retinal diseases. Further research is needed to elucidate the precise molecular mechanisms underlying SCFA-mediated retinal protection and to evaluate the efficacy of targeted therapies in clinical settings.

Multi-Omics Approach to Evaluate Effects of Dietary Sodium Butyrate on Antioxidant Capacity, Immune Function and Intestinal Microbiota Composition in Adult Ragdoll Cats

OBJECTIVES

Sodium butyrate (SB) is a typical postbiotic known to positively affect economic animals in recent years, but research on SB in pet cats is scarce. Consequently, this study sought to explore the influence of SB on anti-inflammatory and antioxidant capacity, immune function, and gut microbiota of adult cats through the assessment of biochemical parameters and comprehensive integrative omics analysis.

METHODS

A total of 30 adult cats were divided into three groups: a basal diet (NC), basal diet with 0.05% SB (SB5), and basal diet with 0.1% SB (SB10). The experiment lasted for 6 weeks.

RESULTS

The results indicated that the fecal level of calprotectin was lower in the SB10 group than in the SB5 and NC groups. The SB10 group reduced the serum levels of TNF-α, IL-1β and DAO compared with the NC group (p < 0.05). In addition, the SB10 diet increased the GSH-Px level and decreased MDA content compared with the NC diet (p < 0.05). Transcriptomic analysis showed that the gene expression of VCAM1 exhibited a notable decrease in the SB10 group compared to the NC group (p < 0.05). The analysis of gut microbiota revealed that the richness of gut microbiota was higher in the SB10 than in the NC group (p < 0.05), and the abundance of Lachnospiraceae, Lachnoclostridium, Blautia, and Roseburia was greater in the SB10 than in the NC group (p < 0.05).

CONCLUSIONS

Dietary SB could enhance the antioxidant and anti-inflammatory capacity, improve immune function, and positively regulate the gut microbiota composition in adult cats.

Differential Analysis of Fecal SCFAs and Their Contribution to Adipogenesis in UCP1 Knock-In Pigs

This study aimed to investigate the changes in fecal short-chain fatty acids (SCFAs) content in UCP1 knock-in pigs (KI pigs) and their effect on adipogenesis. Fecal samples from five 6-month-old wild-type (WT) and KI pigs were collected for targeted metabolomics and 16s rRNA sequencing analyses to identify differences in SCFAs and gut microbiota that may contribute to regulating fat deposition in pigs. The metabolome of pig fecal samples targeted for an analysis of SCFAs identified seven SCFAs, with caproic acid (except isovaleric acid) being the significantly different one. The results of the fecal 16s rRNA analysis demonstrated a notable reduction in the abundance of Streptococcus spp. in the KI pigs in comparison to the WT pigs, with a statistically significant difference. Correlation analyses demonstrated a statistically significant positive correlation between the abundance of Streptococcus spp. and SCFAs, as well as pig body weight and fatness. It was postulated that the reduction in SCFAs in the intestinal tracts of KI pigs may be associated with a reduction in Streptococcus spp. abundance. Compared to WT pigs, the concentration of fecal SCFAs in KI pigs was significantly reduced, which may be related to the decreased abundance of Streptococcus. The in vitro experiments showed that caproic acid could significantly enhance the differentiation efficiency of porcine SVF cells into mature adipocytes by activating the FFAR4 gene.

Zingiber striolatum phytochemicals ameliorated hyperglycemia symptoms by modulating gut microbial communities in mice with type 2 diabetes mellitus

Introduction

Prolonged hyperglycemia caused by type 2 diabetes mellitus (T2DM) can lead to liver injury and disrupt the community of the gut microbiota that pose significant risks to human health. As a food rich in a variety of active ingredients, Zingiber striolatum (Z. striolatum) exhibits hypoglycemic and hypolipidemic effects. However, the regulatory influence of Z. striolatum ethanol extract (ZSE) on the gut microbiota of T2DM mice or its potential relationship with T2DM pathology remains unexplored.

Methods

After a one-week acclimation period, 12 mice were randomly selected as the normal group. The remaining 48 mice were employed T2DM model, and then randomly assigned to four groups: the model group, a low-dose ZSE group (ZSE-L, 100 mg/kg/day), a high-dose ZSE group (ZSE-H, 300 mg/kg/day), and a positive control group treated with metformin hydrochloride (MET, 100 mg/kg/day).

Results

After a 4-week intervention, the results revealed that ZSE significantly ameliorated fasting blood glucose (FBG), area under the curve of oral glucose tolerance test (AUC of OGTT) and glycated serum protein (GSP) in T2DM mice. Moreover, the high-dose (ZSE-H) treatment increased the relative abundance of beneficial bacteria such as Faecalibaculum, while reducing harmful bacteria such as Bilophila, thereby alleviating insulin resistance. Additionally, ZSE-H demonstrated superior efficacy over low-dose (ZSE-L) in improving FBG, AUC of OGTT, and other hypoglycemic parameters. Predictive analysis of the correlation between gut microbiota and hypoglycemic parameters identified Dubosiella, Bacillus, and Mailhella as potential microbial biomarkers for further investigation into the pathogenesis of T2DM.

Conclusion

ZSE plays a pivotal role in mitigating hyperglycemia in T2DM mice through the modulation of intestinal microbiota communities.

Butyric Acid Modulates Gut Microbiota to Alleviate Inflammation and Secondary Bone Loss in Ankylosing Spondylitis

Background: Ankylosing spondylitis (AS) is a chronic inflammatory and autoimmune disease that primarily affects the sacroiliac joints and axial skeleton. While the exact pathogenetic mechanism of AS remains unclear, previous reports have highlighted the involvement of genetic factors, immune responses, and gut microbiota dysregulation in the development of this condition. Short-chain fatty acids (SCFAs), which are microbial fermentation products derived from sugar, protein, and dietary fibers, play a role in maintaining the intestinal barrier function and reducing inflammatory responses. The aim of this study was to investigate the therapeutic potential of butyric acid (BA), an important SCFA, in the treatment of AS. Methods: To evaluate the anti-inflammatory and anti-bone loss effects of BA, a murine AS model was established using proteoglycan and dimethyl dioctadecyl ammonium (DDA) adjuvants. Various techniques, including an enzyme-linked immunosorbent assay (ELISA), magnetic resonance imaging (MRI), micro-CT, histology, quantitative PCR (qPCR) for intestinal tight junction protein expression, and 16S rDNA sequencing to analyze gut microbiota abundance, were employed to assess the inflammation and bone health in the target tissues. Results: The results indicated that BA demonstrated potential in alleviating the inflammatory response in the peripheral joints and the axial spine affected by AS, as evidenced by the reductions in inflammatory infiltration, synovial hyperplasia, and endplate erosion. Furthermore, BA was found to impact the intestinal barrier function positively. Notably, BA was associated with the downregulation of harmful inflammatory factors and the reversal of bone loss, suggesting its protective effects against AS. Conclusions: These beneficial effects were attributed to the modulation of gut microbiota, anti-inflammatory properties, and the maintenance of skeletal metabolic homeostasis. This study contributes new evidence supporting the relationship between gut microbiota and bone health.

Propionate and butyrate counteract renal damage and progression to chronic kidney disease

BACKGROUND

Short-chain fatty acids (SCFAs), mainly acetate, propionate and butyrate, are produced by gut microbiota through fermentation of complex carbohydrates that cannot be digested by the human host. They affect gut health and can contribute at the distal level to the pathophysiology of several diseases, including renal pathologies.

METHODS

SCFA levels were measured in chronic kidney disease (CKD) patients (n = 54) at different stages of the disease, and associations with renal function and inflammation parameters were examined. The impact of propionate and butyrate in pathways triggered in tubular cells under inflammatory conditions was analysed using genome-wide expression assays. Finally, a pre-clinical mouse model of folic acid-induced transition from acute kidney injury to CKD was used to analyse the preventive and therapeutic potential of these microbial metabolites in the development of CKD.

RESULTS

Faecal levels of propionate and butyrate in CKD patients gradually reduce as the disease progresses, and do so in close association with established clinical parameters for serum creatinine, blood urea nitrogen and the estimated glomerular filtration rate. Propionate and butyrate jointly downregulated the expression of 103 genes related to inflammatory processes and immune system activation triggered by tumour necrosis factor-α in tubular cells. In vivo, the administration of propionate and butyrate, either before or soon after injury, respectively, prevented and slowed the progression of damage. This was indicated by a decrease in renal injury markers, the expression of pro-inflammatory and pro-fibrotic markers, and recovery of renal function over the long term.

CONCLUSIONS

Propionate and butyrate levels are associated with a progressive loss of renal function in CKD patients. Early administration of these SCFAs prevents disease advancement in a pre-clinical model of acute renal damage, demonstrating their therapeutic potential independently of the gut microbiota.

Liuweizhiji Gegen-Sangshen beverage protects against alcoholic liver disease in mice through the gut microbiota mediated SCFAs/GPR43/GLP-1 pathway

Introduction

Alcoholic liver disease (ALD) is a pathological state of the liver caused by longterm alcohol consumption. Recent studies have shown that the modulation of the gut microbiota and its metabolic products, specifically the short-chain fatty acids (SCFAs), exert a critical role in the evolution and progression of ALD. The Liuweizhiji Gegen-Sangshen beverage (LGS), as a functional beverage in China, is derived from a traditional Chinese herbal formula and has been clinically applied for ALD treatment, demonstrating significant efficacy. However, the underlying mechanisms of LGS for alleviating ALD involving gut microbiota regulation remain unknown.

Methods

In this study, an ALD murine model based on the National Institute on Alcohol Abuse and Alcoholism (NIAAA) method was established.

Results

The results showed that oral LGS treatment dose-dependently alleviated alcoholinduced liver injury and inflammation in mice through decreasing levels of ALT, AST and proinflammatory cytokines (TNF-α, IL-6, IL-1β). LGS significantly improved liver steatosis, enhanced activities of alcohol metabolizing enzymes (ALDH and ADH), and reduced the CYP2E1 activity. Notably, regarding most detected indices, the effect of LGS (particularly at medium and high dose) was comparable to the positive drug MTDX. Moreover, LGS had a favorable effect on maintaining intestinal barrier function through reducing epithelial injury and increasing expression of occludin. 16S rRNA sequencing results showed that LGS remarkably modulated gut microbiota structure in ALD mice via recovering alcohol-induced microbial changes and specifically mediating enrichment of several bacterial genera (Alloprevotella, Monoglobus, Erysipelatoclostridium Parasutterella, Harryflintia and unclassified_c_Clostridia). Further study revealed that LGS increased production of SCFAs of hexanoic acid in cecum, promoted alcohol-mediated reduction of GRP43 expression in ileum, and increased serum GLP-1 level.

Discussion

Overall, LGS exerts a remarkable protective effect on ALD mice through the gut microbiota mediated specific hexanoic acid production and GPR43/GLP-1 pathway.

Underlying mechanisms of traditional Chinese medicine in the prevention and treatment of diabetic retinopathy: Evidences from molecular and clinical studies

As one of the most serious microvascular complications of diabetes mellitus (DM), diabetic retinopathy (DR) can cause visual impairment and even blindness. With the rapid increase in the prevalence of DM, the incidence of DR is also rising year by year. Preventing and effectively treating DR has become a major focus in the medical field. Traditional Chinese medicine (TCM) has a wealth of experience in treating DR and has achieved significant results with various herbs and TCM prescriptions. Traditional Chinese Medicine (TCM) provides a comprehensive therapeutic strategy for diabetic retinopathy (DR), encompassing anti-inflammatory and antioxidant actions, anti-neovascularization, neuroprotection, regulation of glucose metabolism, and inhibition of apoptosis. This review provides an overview of the current status of TCM treatment for DR in recent years, including experimental studies and clinical researches, to explore the clinical efficacy and the underlying modern mechanisms of herbs and TCM prescriptions. Besides, we also discussed the challenges TCM faces in treating DR, such as drug-drug interactions among TCM components and the lack of high-quality evidence-based medicine practice, which pose significant obstacles to TCM's application in DR.

Alisma plantago-aquatica polysaccharides ameliorate acetaminophen-induced acute liver injury by regulating hepatic metabolic profiles and modulating gut microbiota

Acetaminophen (APAP) has emerged as a predominant contributor to acute liver failure (ALF) in United States. Alismatis rhizoma, a commonly used traditional herbal medicine, contains small molecular components with extensive hepatoprotective activity. However, the specific role of Alismatis rhizoma polysaccharide (ARP) in liver protection remains unclear. ARP50 and ARP70, derived through graded alcohol precipitation and refinement, predominantly consisted of varying proportions of glucose, galactose, and arabinose. In vitro experiments on free radical scavenging demonstrated notable antioxidant capabilities of ARP50 and ARP70. To investigate the hepatoprotective effects, an APAP-induced acute liver injury (ALI) model was established in mice. ARP50 and ARP70 exerted dose-dependent therapeutic effects on APAP-induced liver injury. Further analysis of liver metabolites revealed that ARPs facilitated the reconstruction of the liver antioxidant system by modulating the metabolism network centered on l-glutamine. In addition, the abundance of gut microbiota was altered under the influence of ARPs. ARP50 significantly reduced the levels of Pseudarthrobacter and markedly increased the levels of Faecalibacterium，At the same time, ARP50 could increase the levels of acetic acid in the liver and serum. Meanwhile, ARP70 significantly increased the abundance of Dubosiella, Muribaculum, Ileibacterium, and Prevotellaceae UCG 001, while reducing the abundance of Escherichia Shigella and Pseudarthrobacter. The results indicated that ARPs could exert a protective effect against APAP-induced acute liver injury by reshaping the liver metabolic profile and modulating the gut microbiota.

Metabolomics Reveals the Mechanism by Which Sodium Butyrate Promotes the Liver Pentose Phosphate Pathway and Fatty Acid Synthesis in Lactating Goats

This study aimed to explore the effects of sodium butyrate on liver metabolism in goats subjected to a high-concentrate diet. We randomly assigned twelve Saanen-lactating goats into two groups, one of which received a high-concentrate diet (concentrate: forage = 60:40, control group), while the other received the same basal diet supplemented with sodium butyrate (SB) (10 g/kg basal diet, SB group). Compared with the control diet, the SB diet considerably increased the milk fat percentage and content (p < 0.05), with an increase of 0.67% in the milk fat content of the SB group. By employing a global metabolomics approach based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), we identified 6748 ions in ESI+ mode and 3573 ions in ESI- mode after liver isolation from both groups. A total of twenty-three metabolites, including phospholipids, fatty acids, and ribose phosphate, were found to be dysregulated according to a search against the human metabolome database (HMDB). Pathway analysis revealed activation of the pentose phosphate pathway, glycerophospholipid metabolism, and unsaturated fatty acid synthesis. The SB diet also modulated the expression of key lipogenic enzymes, such as acetyl-CoA carboxylase (ACC) and stearoyl-CoA desaturase (SCD-1), which are downstream targets of the transcription factor sterol regulatory element-binding proteins-1c (SREBP-1c), inducing a significant upregulation (p < 0.05). Furthermore, 6-phosphogluconate dehydrogenase (6PGDH) levels in the liver were elevated after the lactating goats were fed the SB diet (p < 0.05). Our study reveals that the SB diet may offer substantial benefits in enhancing the milk quality of subacute ruminal acidosis (SARA) goats. This is accomplished by augmenting the activity of the liver pentose phosphate pathway and the process of de novo fatty acid synthesis in lactating goats.

Dietary therapy of murine primary biliary cholangitis induces hepatocellular steatosis: A cautionary tale

BACKGROUND AND AIMS

There is increased interest in utilizing dietary interventions to alter the progression of autoimmune diseases. These efforts are driven by associations of gut microbiota/metabolites with levels of short-chain fatty acids (SCFAs). Propionate is a key SCFA that is commonly used as a food preservative and is endogenously generated by bacterial fermentation of non-digestible carbohydrates in the gut. A thesis has suggested that a diet rich in propionate and other SCFAs can successfully modulate autoimmunity. Herein, we investigated the effect of long-term administration of propionylated high-amylose resistant starches (HAMSP) on the course of murine primary biliary cholangitis.

MATERIALS AND METHODS

Groups of female ARE-Del mice were fed an HAMSP diet either before or after disease onset. A detailed immunobiological analysis was performed involving autoantibodies and rigorous T-cell phenotyping, including enumeration of T-cell subsets in the spleen, liver, intestinal intraepithelial lymphocytes and lamina propria by flow cytometry. Histopathological scores were used to assess the frequency and severity of liver inflammation and damage to hepatocytes and bile ducts.

RESULTS

Our results demonstrate that a long-term propionate-yielding diet re-populated the T-cell pool with decreased naïve and central memory T-cell subsets and an increase in the effector memory T cells in mice. Similarly, long-term HAMSP intake reduced CD4+CD8+ double-positive T cells in intraepithelial lymphocytes and the intestinal lamina propria. Critically, HAMSP consumption led to moderate-to-severe hepatocellular steatosis in ARE-Del mice, independent of the stage of autoimmune cholangitis.

CONCLUSIONS

Our data suggest that administration of HAMSP induces both regulatory and effector T cells. Furthermore, HAMSP administration resulted in hepatocellular steatosis. Given the interest in dietary modulation of autoimmunity and because propionate is widely used as a food preservative, these data have significant implications. This study also provides new insights into the immunological and pathological effects of chronic propionate exposure.

Study on the protective effect of Aronia melanocarpa extract on type 2 diabetes by regulating glucose and lipid metabolism through intestinal flora

Aronia melanocarpa, a plant rich in anthocyanins, has been studied for its potential to regulate blood sugar and blood lipids, although the specific mechanism is not yet understood. This research aims to identify the differential bacterial flora and elucidate the mechanism by which it improves glucose and lipid metabolism disorders through 16S rDNA gene sequencing. The study reveals the protective effect of Aronia melanocarpa extract (AME) on liver damage in type 2 diabetic rats. Experimental results demonstrate that AME can effectively modulate the abundance of intestinal flora, reduce colon tissue damage, enhance the weight of diabetic rats, and lower levels of fasting blood sugar, low-density lipoprotein (LDL), and triglycerides (TG). Additionally, liver morphology analysis shows that AME can effectively mitigate liver tissue structural damage in type 2 diabetic rats. In conclusion, AME regulates glucose and lipid metabolism by influencing intestinal flora, ultimately regulating glucose and lipid metabolism in type 2 diabetic rats.

Gut microbiota and eye diseases: A review

Recent studies reveal that alterations in gut microbiota play a significant role in the progression of various diseases, including those affecting the eyes. The association between gut microbiota and eye health is an emerging focus of research. This review seeks to summarize the connection between the gut microbiome and specific eye conditions, such as ocular surface diseases, funduscopic disorders and immune-mediated eye diseases. Gut microbiota may influence these conditions by regulating the immune system or altering metabolites, thereby contributing to disease development. Strategies like probiotics, antibiotics, dietary modifications, and fecal transplants show promise in addressing these issues. This review examines how the gut microbiome may be linked to the pathogenesis of eye diseases, providing fresh therapeutic perspectives for ophthalmology.

Matcha alleviates obesity by modulating gut microbiota and its metabolites

Matcha shows promise for diabetes, obesity, and gut microbiota disorders. Studies suggest a significant link between gut microbiota, metabolites, and obesity. Thus, matcha may have a positive impact on obesity by modulating gut microbiota and metabolites. This study used 16S rDNA sequencing and untargeted metabolomics to examine the cecal contents in mice. By correlation analysis, we explored the potential mechanisms responsible for the positive effects of matcha on obesity. The results indicated that matcha had a mitigating effect on the detrimental impacts of a high-fat diet (HFD) on multiple physiological indicators in mice, including body weight, adipose tissue weight, serum total cholesterol (TC), and low-density lipoprotein (LDL) levels, as well as glucose tolerance. Moreover, it was observed that matcha had an impact on the structural composition of gut microbiota and gut metabolites. Specifically, matcha was able to reverse the alterations in the abundance of certain obesity-improving bacteria, such as Alloprevotella, Ileibacterium, and Rikenella, as well as the abundance of obesity-promoting bacteria Romboutsia, induced by a HFD. Furthermore, matcha can influence the levels of metabolites, including formononetin, glutamic acid, pyroglutamic acid, and taurochenodeoxycholate, within the gastrointestinal tract. Additionally, matcha enhances caffeine metabolism and the HIF-1 signaling pathway in the KEGG pathway. The results of the correlation analysis suggest that formononetin, theobromine, 1,3,7-trimethyluric acid, and Vitamin C displayed negative correlation with both the obesity phenotype and microbiota known to exacerbate obesity, while demonstrating positive correlations with microbiota that alleviated obesity. However, glutamic acid, pyroglutamic acid, and taurochenodeoxycholate had the opposite effect. In conclusion, the impact of matcha on gut metabolites may be attributed to its modulation of the abundance of Alloprevotella, Ileibacterium, Rikenella, and Romboutsia within the gastrointestinal tract, thereby potentially contributing to the amelioration of obesity.

The potential role of gut microbiota-derived metabolites as regulators of metabolic syndrome-associated mitochondrial and endolysosomal dysfunction in Alzheimer's disease

Although the role of gut microbiota (GMB)-derived metabolites in mitochondrial and endolysosomal dysfunction in Alzheimer's disease (AD) under metabolic syndrome remains unclear, deciphering these host-metabolite interactions represents a major public health challenge. Dysfunction of mitochondria and endolysosomal networks (ELNs) plays a crucial role in metabolic syndrome and can exacerbate AD progression, highlighting the need to study their reciprocal regulation for a better understanding of how AD is linked to metabolic syndrome. Concurrently, metabolic disorders are associated with alterations in the composition of the GMB. Recent evidence suggests that changes in the composition of the GMB and its metabolites may be involved in AD pathology. This review highlights the mechanisms of metabolic syndrome-mediated AD development, focusing on the interconnected roles of mitochondrial dysfunction, ELN abnormalities, and changes in the GMB and its metabolites. We also discuss the pathophysiological role of GMB-derived metabolites, including amino acids, fatty acids, other metabolites, and extracellular vesicles, in mediating their effects on mitochondrial and ELN dysfunction. Finally, this review proposes therapeutic strategies for AD by directly modulating mitochondrial and ELN functions through targeting GMB metabolites under metabolic syndrome.

Sequence analysis of microbiota in clinical human cases with diabetic foot ulcers from China

Background

Diabetic foot ulcers (DFU) seriously threaten the health and quality of life of patients. The microbiota is the primary reason for the refractory and high recurrence of DFU. This study aimed to determine the wound microbiota at different DFU stages.

Methods

Wound samples were collected from 48 patients with DFU and divided into three phases: inflammatory (I, n = 49), proliferation (P, n = 22), and remodeling (R, n = 19). The wound samples obtained at different stages were then subjected to 16S rRNA gene sequencing. The number of operational taxonomic units (OTUs) in the different groups was calculated according to the criterion of 97 % sequence similarity. The diversity of the microbiota differentially presented bacterial taxa at the phylum and genus levels, and important phyla and genera in the different groups were further explored.

Results

After sequencing, 3351, 925, and 777 OTUs were observed in groups I, P, and R, respectively, and 175 OTUs overlapped. Compared with the inflammatory stage, the α-diversity of wound microbiota at proliferation and remodeling stages was significantly decreased (P < 0.05). At the phylum level, Firmicutes, Proteobacteria, Actinobacteriota, and Bacteroidota were the dominant phyla, accounting for more than 90 % of all the phyla. At the genus level, Random Forest and linear discriminant analysis effect size analyses showed that Peptoniphilus, Lactobacillus, Prevotella, Veillonella, Dialister, Streptococcus, and Ruminococcus were the signature wound microbiota for the inflammatory stage; Anaerococcus, Ralstonia, Actinomyces, and Akkermansia were important species for the proliferation stage; and the crucial genera for the remodeling stage were Enterobacter, Pseudomonas, Sondgrassella, Bifidobacterium, and Faecalibacterium.

Conclusions

There were significant differences in the composition and structure of the wound microbiota in patients with DFU at different stages, which may lay a foundation for effectively promoting wound healing in DFU.

The Role of Short Chain Fatty Acids in Inflammation and Body Health

Short chain fatty acids (SCFAs), mainly including acetate, propionate and butyrate, are produced by intestinal bacteria during the fermentation of partially digested and indigestible polysaccharides. SCFAs play an important role in regulating intestinal energy metabolism and maintaining the homeostasis of the intestinal environment and also play an important regulatory role in organs and tissues outside the gut. In recent years, many studies have shown that SCFAs can regulate inflammation and affect host health, and two main signaling mechanisms have also been identified: the activation of G-protein coupled receptors (GPCRs) and inhibition of histone deacetylase (HDAC). In addition, a growing body of evidence highlights the importance of every SCFA in influencing health maintenance and disease development. In this review, we summarized the recent advances concerning the biological properties of SCFAs and their signaling pathways in inflammation and body health. Hopefully, it can provide a systematic theoretical basis for the nutritional prevention and treatment of human diseases.

Understanding how pre- and probiotics affect the gut microbiome and metabolic health

The gut microbiome, a complex assembly of microorganisms, significantly impacts human health by influencing nutrient absorption, the immune system, and disease response. These microorganisms form a dynamic ecosystem that is critical to maintaining overall well-being. Prebiotics and probiotics are pivotal in regulating gut microbiota composition. Prebiotics nourish beneficial bacteria and promote their growth, whereas probiotics help maintain balance within the microbiome. This intricate balance extends to several aspects of health, including maintaining the integrity of the gut barrier, regulating immune responses, and producing metabolites crucial for metabolic health. Dysbiosis, or an imbalance in the gut microbiota, has been linked to metabolic disorders such as type 2 diabetes, obesity, and cardiovascular disease. Impaired gut barrier function, endotoxemia, and low-grade inflammation are associated with toll-like receptors influencing proinflammatory pathways. Short-chain fatty acids derived from microbial fermentation modulate anti-inflammatory and immune system pathways. Prebiotics positively influence gut microbiota, whereas probiotics, especially Lactobacillus and Bifidobacterium strains, may improve metabolic outcomes, such as glycemic control in diabetes. It is important to consider strain-specific effects and study variability when interpreting these findings, highlighting the need for further research to optimize their therapeutic potential. The aim of this report is therefore to review the role of the gut microbiota in metabolic health and disease and the effects of prebiotics and probiotics on the gut microbiome and their therapeutic role, integrating a broad understanding of physiological mechanisms with a clinical perspective.

Gut microbiome signatures associated with type 2 diabetes in obesity in Mongolia

Mongolian people possess a unique dietary habit characterized by high consumption of meat and dairy products and fewer vegetables, resulting in the highest obesity rate in East Asia. Although obesity is a known cause of type 2 diabetes (T2D), the T2D rate is moderate in this population; this is known as the "Mongolian paradox." Since the gut microbiota plays a key role in energy and metabolic homeostasis as an interface between food and body, we investigated gut microbial factors involved in the prevention of the co-occurrence of T2D with obesity in Mongolians. We compared the gut microbiome and metabolome of Mongolian adults with obesity with T2D (DO: n = 31) or without T2D (NDO: n = 35). Dysbiotic signatures were found in the gut microbiome of the DO group; lower levels of Faecalibacterium and Anaerostipes which are known as short-chain fatty acid (SCFA) producers and higher levels of Methanobrevibacter, Desulfovibrio, and Solobacterium which are known to be associated with certain diseases. On the other hand, the NDO group exhibited a higher level of fecal SCFA concentration, particularly acetate. This is consistent with the results of the whole shotgun metagenomic analysis, which revealed a higher relative abundance of SCFA biosynthesis-related genes encoded largely by Anaerostipes hadrus in the NDO group. Multiple logistic regression analysis including host demographic parameters indicated that acetate had the highest negative contribution to the onset of T2D. These findings suggest that SCFAs produced by the gut microbial community participate in preventing the development of T2D in obesity in Mongolians.

Intervention with fructooligosaccharides, Saccharomyces boulardii, and their combination in a colitis mouse model

Objective

To examine the effects of an intervention with fructooligosaccharides (FOS), Saccharomyces boulardii, and their combination in a mouse model of colitis and to explore the mechanisms underlying these effects.

Methods

The effects of FOS, S. boulardii, and their combination were evaluated in a DSS-induced mouse model of colitis. To this end, parameters such as body weight, the disease activity index (DAI), and colon length were examined in model mice. Subsequently, ELISA was employed to detect the serum levels of proinflammatory cytokines. Histopathological analysis was performed to estimate the progression of inflammation in the colon. Gas chromatography was used to determine the content of short-chain fatty acids (SCFAs) in the feces of model mice. Finally, 16S rRNA sequencing technology was used to analyze the gut microbiota composition.

Results

FOS was slight effective in treating colitis and colitis-induced intestinal dysbiosis in mice. Meanwhile, S. boulardii could significantly reduced the DAI, inhibited the production of IL-1β, and prevented colon shortening. Nevertheless, S. boulardii treatment alone failed to effectively regulate the gut microbiota. In contrast, the combined administration of FOS/S. boulardii resulted in better anti-inflammatory effects and enabled microbiota regulation. The FOS/S. boulardii combination (109 CFU/ml and 107 CFU/ml) significantly reduced the DAI, inhibited colitis, lowered IL-1β and TNF-α production, and significantly improved the levels of butyric acid and isobutyric acid. However, FOS/S. boulardii 109 CFU/ml exerted stronger anti-inflammatory effects, inhibited IL-6 production and attenuated colon shortening. Meanwhile, FOS/S. boulardii 107 CFU/ml improved microbial regulation and alleviated the colitis-induced decrease in microbial diversity. The combination of FOS and S. boulardii significantly increased the abundance of Parabacteroides and decreased the abundance of Escherichia-Shigella. Additionally, it promoted the production of acetic acid and propionic acid.

Conclusion

Compared with single administration, the combination can significantly increase the abundance of beneficial bacteria such as lactobacilli and Bifidobacteria and effectively regulate the gut microbiota composition. These results provide a scientific rationale for the prevention and treatment of colitis using a FOS/S. boulardii combination. They also offer a theoretical basis for the development of nutraceutical preparations containing FOS and S. boulardii.

Unveiling the gut-eye axis: how microbial metabolites influence ocular health and disease

The intricate interplay between the gut microbiota and ocular health has surpassed conventional medical beliefs, fundamentally reshaping our understanding of organ interconnectivity. This review investigates into the intricate relationship between gut microbiota-derived metabolites and their consequential impact on ocular health and disease pathogenesis. By examining the role of specific metabolites, such as short-chain fatty acids (SCFAs) like butyrate and bile acids (BAs), herein we elucidate their significant contributions to ocular pathologies, thought-provoking the traditional belief of organ sterility, particularly in the field of ophthalmology. Highlighting the dynamic nature of the gut microbiota and its profound influence on ocular health, this review underlines the necessity of comprehending the complex workings of the gut-eye axis, an emerging field of science ready for further exploration and scrutiny. While acknowledging the therapeutic promise in manipulating the gut microbiome and its metabolites, the available literature advocates for a targeted, precise approach. Instead of broad interventions, it emphasizes the potential of exploiting specific microbiome-related metabolites as a focused strategy. This targeted approach compared to a precision tool rather than a broad-spectrum solution, aims to explore the therapeutic applications of microbiome-related metabolites in the context of various retinal diseases. By proposing a nuanced strategy targeted at specific microbial metabolites, this review suggests that addressing specific deficiencies or imbalances through microbiome-related metabolites might yield expedited and pronounced outcomes in systemic health, extending to the eye. This focused strategy holds the potential in bypassing the irregularity associated with manipulating microbes themselves, paving a more efficient pathway toward desired outcomes in optimizing gut health and its implications for retinal diseases.

Resveratrol improves diabetic kidney disease by modulating the gut microbiota-short chain fatty acids axis in db/db mice

Diabetic kidney disease is associated with the dysbiosis of the gut microbiota and its metabolites. db/db mice were fed chow diet with or without 0.4% resveratrol for 12 weeks, after which the gut microbiota, faecal short-chain fatty acids (SCFAs), and renal fibrosis were analysed. Resveratrol ameliorated the progression of diabetic kidney disease and alleviated tubulointerstitial fibrosis. Further studies showed that gut microbiota dysbiosis was modulated by resveratrol, characterised by the expansion of SCFAs-producing bacteria Faecalibaculum and Lactobacillus, which increased the concentrations of SCFAs (especially acetic acid) in the faeces. Moreover, microbiota transplantation experiments found that alteration of the gut microbiota contributed to the prevention of diabetic kidney disease. Acetate treatment ameliorated proteinuria, glomerulosclerosis and tubulointerstitial fibrosis in db/db mice. Overall, resveratrol improved the progression of diabetic kidney disease by suppressing tubulointerstitial fibrosis, which may be involved, at least in part, in the regulation of the gut microbiota-SCFAs axis.

Effects of coated sodium butyrate on the growth performance, serum biochemistry, antioxidant capacity, intestinal morphology, and intestinal microbiota of broiler chickens

Introduction

This study examined the impact of adding coated sodium butyrate (CSB) to the diet on the growth performance, serum biochemistry, antioxidant capacity, intestinal morphology, and cecal microbiota of yellow-feathered broiler chickens.

Methods

In this study, 240 yellow-feathered broiler chickens at 26 days old were divided into two groups: the control group (CON group) received a standard diet, and the experimental group (CSB group) received a diet with 0.5 g/kg of a supplement called CSB. Each group had 6 replicates, with 20 chickens in each replicate, and the experiment lasted for 36 days.

Results

Compared to the CON group, the CSB group showed a slight but insignificant increase in average daily weight gain during the 26-62 day period, while feed intake significantly decreased. The CSB group exhibited significant increases in serum superoxide dismutase, catalase, and total antioxidant capacity. Additionally, the CSB group had significant increases in total protein and albumin content, as well as a significant decrease in blood ammonia levels. Compared to the CON group, the CSB group had significantly increased small intestine villus height and significantly decreased jejunal crypt depth. The abundance of Bacteroidetes and Bacteroides in the cecal microbiota of the CSB group was significantly higher than that of the CON group, while the abundance of Proteobacteria, Deferribacteres, and Epsilonbacteraeota was significantly lower than that of the CON group.

Conclusion

These results suggest that adding CSB to the diet can improve the growth performance and antioxidant capacity of yellow-feathered broiler chickens while maintaining intestinal health.

Postbiotics: emerging therapeutic approach in diabetic retinopathy

Diabetic retinopathy (DR) is a prevalent microvascular complication in diabetic patients that poses a serious risk as it can cause substantial visual impairment and even vision loss. Due to the prolonged onset of DR, lengthy treatment duration, and limited therapeutic effectiveness, it is extremely important to find a new strategy for the treatment of DR. Postbiotic is an emerging dietary supplement which consists of the inactivate microbiota and its metabolites. Numerous animal experiments have demonstrated that intervention with postbiotics reduces hyperglycemia, attenuates retinal peripapillary and endothelial cell damage, improves retinal microcirculatory dysfunction, and consequently delays the progression of DR. More strikingly, unlike conventional probiotics and prebiotics, postbiotics with small molecules can directly colonize the intestinal epithelial cells, and exert heat-resistant, acid-resistant, and durable for storage. Despite few clinical significance, oral administration with postbiotics might become the effective management for the prevention and treatment of DR. In this review, we summarized the basic conception, classification, molecular mechanisms, and the advances in the therapeutic implications of postbiotics in the pathogenesis of DR. Postbiotics present great potential as a viable adjunctive therapy for DR.

Insights into the liver-eyes connections, from epidemiological, mechanical studies to clinical translation

Maintenance of internal homeostasis is a sophisticated process, during which almost all organs get involved. Liver plays a central role in metabolism and involves in endocrine, immunity, detoxification and storage, and therefore it communicates with distant organs through such mechanisms to regulate pathophysiological processes. Dysfunctional liver is often accompanied by pathological phenotypes of distant organs, including the eyes. Many reviews have focused on crosstalk between the liver and gut, the liver and brain, the liver and heart, the liver and kidney, but with no attention paid to the liver and eyes. In this review, we summarized intimate connections between the liver and the eyes from three aspects. Epidemiologically, we suggest liver-related, potential, protective and risk factors for typical eye disease as well as eye indicators connected with liver status. For molecular mechanism aspect, we elaborate their inter-organ crosstalk from metabolism (glucose, lipid, proteins, vitamin, and mineral), detoxification (ammonia and bilirubin), and immunity (complement and inflammation regulation) aspect. In clinical application part, we emphasize the latest advances in utilizing the liver-eye axis in disease diagnosis and therapy, involving artificial intelligence-deep learning-based novel diagnostic tools for detecting liver disease and adeno-associated viral vector-based gene therapy method for curing blinding eye disease. We aim to focus on and provide novel insights into liver and eyes communications and help resolve existed clinically significant issues.

Research progress of diabetic retinopathy and gut microecology

According to the prediction of the International Diabetes Federation, global diabetes mellitus (DM) patients will reach 783.2 million in 2045. The increasing incidence of DM has led to a global epidemic of diabetic retinopathy (DR). DR is a common microvascular complication of DM, which has a significant impact on the vision of working-age people and is one of the main causes of blindness worldwide. Substantial research has highlighted that microangiopathy and chronic low-grade inflammation are widespread in the retina of DR. Meanwhile, with the introduction of the gut-retina axis, it has also been found that DR is associated with gut microecological disorders. The disordered structure of the GM and the destruction of the gut barrier result in the release of abnormal GM flora metabolites into the blood circulation. In addition, this process induced alterations in the expression of various cytokines and proteins, which further modulate the inflammatory microenvironment, vascular damage, oxidative stress, and immune levels within the retina. Such alterations led to the development of DR. In this review, we discuss the corresponding alterations in the structure of the GM flora and its metabolites in DR, with a more detailed focus on the mechanism of gut microecology in DR. Finally, we summarize the potential therapeutic approaches of DM/DR, mainly regulating the disturbed gut microecology to restore the homeostatic level, to provide a new perspective on the prevention, monitoring, and treatment of DR.