Changes In Short-chain Fatty Acids Research Articles

Antibiotics and probiotics-induced effects on the total fatty acid composition of feces in a rat model

Fatty acids (FAs) play important roles as membrane components and signal transduction molecules. Changes in short chain FA (SCFA) composition are associated with gut microbiota modifications. However, the effect of bacteria-driven changes on the detailed FA spectrum has not been explored yet. We investigated the effect of antibiotics (ABx) and/or probiotics, in four treatment groups on rat stool FA composition. Principal component analysis indicated that the chromatogram profiles of the treatment groups differ, which was also observed at different time points. Linear mixed effects models showed that in the parameters compared (sampling times, treatments. and their interactions), both the weight percentage and the concentration of FAs were affected by ABx and probiotic administration. This study found that the gut microbiome defines trans and branched saturated FAs, most saturated FAs, and unsaturated FAs with less carbon atoms. These results are among the first ones to demonstrate the restoring effects of a probiotic mixture on a substantial part of the altered total FA spectrum, and also revealed a previously unknown relationship between gut bacteria and a larger group of FAs. These findings suggest that intestinal bacteria produce not only SCFAs but also other FAs that may affect the host’s physiological processes.

Effects of chronic unpredictable mild stress on gut microbiota and fecal amino acid and short-chain fatty acid pathways in mice

Depression is a serious disease that has a significant impact on social functioning. However, the exact causes of depression are still not fully understood. Therefore, it is necessary to explore new pathways leading to depression. In this study, we used 16 S rDNA to examine changes in gut microbiota and predict related pathways in depression-like mice. Additionally, we employed liquid chromatography-mass spectrometry (LC-MS) to identify changes in amino acids and gas chromatography-mass spectrometry (GC-MS) to identify changes in short-chain fatty acids (SCFAs) in fecal samples. We conducted Pearson/Spearman correlation analysis to investigate the associations between changes in amino acids/SCFAs and behavioral outcomes. The 16 S rDNA sequencing revealed significant alterations in gut microbiota at the phylum and genus levels in mice subjected to chronic unpredictable mild stress (CUMS). The relative abundances of Bacteroidetes, Proteobacteria, Bacteroides, and Alloprevotella were increased, while Firmicutes, Verrucomicrobia, Actinobacteria, Lactobacillus, Akkermansia, Lachnospirillum, and Enterobacter were decreased in the CUMS mice. We used PICRUSt software to annotate the kyoto encyclopedia of genes and genomes (KEGG) pathway function related to depression-like behavior in mice. Our analysis identified sixty functional pathways associated with the gut microbiota of mice exhibiting depression-like behavior. In the amino acid concentration analysis, we observed decreased levels of hydroxyproline and tryptophan, and increased levels of alanine in CUMS mice. In the SCFAs concentration assay, we found decreased levels of butyric acid and valeric acid, and increased levels of acetic acid in CUMS mice. Some of these changes were significantly correlated with depressive-like behaviors. Our study contributes to the understanding of the mechanism of the gut-brain axis in the occurrence and development of depression.

Intestinal microbiota features of children born by cesarean section and its correction

Introduction. Studying the gut microbiota of C-section newborns and its correction is a topical problem at present.Aim. To study the process of gut microbiota formation in healthy C-section infants, and the option for its correction using a Lactobacillus reuteri strain DSM 17938 probiotic.Materials and methods. A total of 80 healthy newborns were included in the study. Of these, 59 completed the study: the treatment group consisted of 36 elective caesarean (EC)-section infants and the control group was made up of 23 vaginally delivered infants. Newborns of the treatment study group were randomized into subgroups, one of which received the L. reuteri strain DSM 17938 (L subgroup) probiotic, and the second one did not receive it (0 subgroup). During the entire period of the study, infants were exclusively breastfed. The gut microbiota was analysed with the 16S rRNA sequencing method, and the metabolic activity of the gut microbiota was additionally assessed using gas-liquid chromatography.Results and discussion. The metagenomic analysis showed that the taxonomic richness and biological diversity of the gut microbiota in L subgroup infants increased in time interval 3, which indicated the active effect of the strain on the infant microbiota by Exposure Day 30. The gas-liquid chromatography analysis showed more pronounced changes in short-chain fatty acids in infants of the L subgroup: they were more similar to the findings in the control group (vaginal delivery). Also, bowel problems and allergies occurred less frequently in infants of this subgroup and they less frequently suffered from respiratory diseases during the year. The study showed the association between the mode of delivery and changes in anthropometric measurements.Conclusion. The use of L. reuteri strain DSM 17938 probiotic had a significant effect on the formation of the microbiota by the 30th day of age. A daily long-term addition of a L. reuteri strain DSM 17938 probiotic can prevent early microbiota dysbiosis and have a protective effect in later age period.

Short Chain Fatty Acids: Essential Weapons of Traditional Medicine in Treating Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal inflammatory disease, mainly including Crohn's disease (CD) and ulcerative colitis (UC). In recent years, the incidence and prevalence of IBD have been on the rise worldwide and have become a significant concern of health and a huge economic burden on patients. The occurrence and development of IBD involve a variety of pathogenic factors. The changes in short-chain fatty acids (SCFAs) are considered to be an important pathogenic mechanism of this disease. SCFAs are important metabolites in the intestinal microbial environment, which are closely involved in regulating immune, anti-tumor, and anti-inflammatory activities. Changes in metabolite levels can reflect the homeostasis of the intestinal microflora. Recent studies have shown that SCFAs provide energy for host cells and intestinal microflora, shape the intestinal environment, and regulate the immune system, thereby regulating intestinal physiology. SCFAs can effectively reduce the incidence of enteritis, cardiovascular disease, colon cancer, obesity, and diabetes, and also play an important role in maintaining the balance of energy metabolism (mainly glucose metabolism) and improving insulin tolerance. In recent years, many studies have shown that numerous decoctions and natural compounds of traditional Chinese medicine have shown promising therapeutic activities in multiple animal models of colitis and thus attracted increasing attention from scientists in the study of IBD treatment. Some of these traditional Chinese medicines or compounds can effectively alleviate colonic inflammation and clinical symptoms by regulating the generation of SCFAs. This study reviews the effects of various traditional Chinese medicines or bioactive substances on the production of SCFAs and their potential impacts on the severity of colonic inflammation. On this basis, we discussed the mechanism of SCFAs in regulating IBD-associated inflammation, as well as the related regulatory factors and signaling pathways. In addition, we provide our understanding of the limitations of current research and the prospects for future studies on the development of new IBD therapies by targeting SCFAs. This review may widen our understanding of the effect of traditional medicine from the view of SCFAs and their role in alleviating IBD animal models, thus contributing to the studies of IBD researchers.

The Effect of Theaflavins on the Gut Microbiome and Metabolites in Diabetic Mice.

With the development of diabetes, the gut microbiome falls into a state of dysbiosis, further affecting its progression. Theaflavins (TFs), a type of tea polyphenol derivative, show anti-diabetic properties, but their effect on the gut microbiome in diabetic mice is unclear. It is unknown whether the improvement of TFs on hyperglycemia and hyperlipidemia in diabetic mice is related to gut microbiota. Therefore, in this study, different concentrations of TFs were intragastrically administered to mice with diabetes induced by a high-fat-diet to investigate their effects on blood glucose, blood lipid, and the gut microbiome in diabetic mice, and the plausible mechanism underlying improvement in diabetes was explored from the perspective of the gut microbiome. The results showed that the TFs intervention significantly improved the hyperglycemia and hyperlipidemia of diabetic mice and affected the structure of the gut microbiome by promoting the growth of bacteria positively related to diabetes and inhibiting those negatively related to diabetes. The changes in short-chain fatty acids in mice with diabetes and functional prediction analysis suggested that TFs may affect carbohydrate metabolism and lipid metabolism by regulating the gut microbiome. These findings emphasize the ability of TFs to shape the diversity and structure of the gut microbiome in mice with diabetes induced by a high-fat diet combined with streptozotocin and have practical implications for the development of functional foods with TFs.

The protective effect of small black soybean (Vigna Mungo L.) polysaccharide on acetic acid-induced gastric ulcer in SD rats and its impact on gut microbiota and metabolites

Small black soybean (Vigna Mungo L.) is a kind of medicinal and edible plant with many potential health benefits for the human body. In this study, we investigated the potential anti-gastric ulcer effect of Vigna Mungo L. polysaccharides (VMP) using an acetic acid-induced gastric ulcer model in SD rats. The impact of VMP on the levels of antioxidant factors and growth factors in gastric tissue homogenate, serum metabolites, short-chain fatty acids (SCFAs) and gut microbiota in SD rats were analyzed. The results revealed that VMP exhibited a beneficial role in facilitating the healing process of gastric ulcers, specifically by reducing the area of gastric ulcers, increasing the levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF), and improving oxidative stress status. Additionally, VMP modulated 20 potential serum biomarkers associated with gastric ulcers, thereby exerting a significant impact on multiple crucial metabolic pathways. Notably, VMP notably increased the levels of SCFAs, including acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid, n-valeric acid, in the colonic contents of rats with gastric ulcers. Furthermore, VMP effectively ameliorated gut microbiota dysbiosis in gastric ulcer rats by reducing the relative abundance of Firmicutes, Lachnospiraceae_NK4A136_group, Quinella and Lactobacillus, while increasing the relative abundance of Bacteroidota, Bacteroides, Oscillospiraceae_UCG-005, Muribaculaceae, Parasutterella and Ruminococcus. Correlation analysis showed that the relative abundance of Parasutterella and Lachnospiraceae_NK4A136_group were closely related to the changes of SCFAs and serum metabolites. These findings provide potential groundwork for the development of health products aimed at preventing and treating gastric ulcers.

Gut Microbiota and Derived Short-Chain Fatty Acids Are Linked to Evolution of Heart Failure Patients.

There is a lack of direct evidence regarding gut microbiota dysbiosis and changes in short-chain fatty acids (SCFAs) in heart failure (HF) patients. We sought to assess any association between gut microbiota composition, SCFA production, clinical parameters, and the inflammatory profile in a cohort of newly diagnosed HF patients. In this longitudinal prospective study, we enrolled eighteen newly diagnosed HF patients. At admission and after 12 months, blood samples were collected for the assessment of proinflammatory cytokines, monocyte populations, and endothelial dysfunction, and stool samples were collected for analysis of gut microbiota composition and quantification of SCFAs. Twelve months after the initial HF episode, patients demonstrated improved clinical parameters and reduced inflammatory state and endothelial dysfunction. This favorable evolution was associated with a reversal of microbiota dysbiosis, consisting of the increment of health-related bacteria, such as genus Bifidobacterium, and levels of SCFAs, mainly butyrate. Furthermore, there was a decrease in the abundance of pathogenic bacteria. In vitro, fecal samples collected after 12 months of follow-up exhibited lower inflammation than samples collected at admission. In conclusion, the favorable progression of HF patients after the initial episode was linked to the reversal of gut microbiota dysbiosis and increased SCFA production, particularly butyrate. Whether restoring butyrate levels or promoting the growth of butyrate-producing bacteria could serve as a complementary treatment for these patients deserves further studies.

Unraveling the gut microbiota and short-chain fatty acids characteristics and associations in a cancer cachexia mouse model

ObjectiveCachexia is a common pathological condition in cancer patients, affecting prognosis and treatment outcomes. The relationship between cachexia and gut microbiota and short-chain fatty acids (SCFAs) remains understudied. This research aimed to establish a cachexia mouse model and explore the gut microbiota-SCFAs connection. The study provides fundamental insights into the regulatory mechanisms of cancer cachexia and potential therapeutic strategies. MethodsA cachexia mouse model was created using C26 cells, with relevant indicators measured. Histological and immunohistochemical analyses assessed muscle structure and protein expression. ELISA was performed to detect the levels of IL-1β, IL-6, TNF-α, and LPS in serum to evaluate inflammation.16S rDNA sequencing and GC-MS quantified gut microbiota and SCFAs. Bioinformatics analysis identified indicator species and explored microbiota-SCFAs correlations.ROC analysis was performed to assess the potential of gut microbiota and SCFAs in identifying cachexia. ResultsThe cachexia mouse model exhibited weight loss, muscle atrophy, and elevated inflammatory factors. Gut microbiota in cachexia mice showed decreased diversity and imbalance. Fourteen bacterial genera were identified as potential cachexia indicators. Functional prediction indicated alterations in the functional composition of gut microbial communities in cachexia mice, particularly in carbohydrate and lipid metabolism pathways. Four SCFAs showed significant changes, potentially serving as diagnostic factors. Specific microbial taxa were positively or negatively correlated with changes in SCFAs, and these microbial taxa and differential SCFAs were also correlated with inflammatory cytokines. ConclusionOur study uncovers the gut microbiota and SCFAs features in a cachexia mouse model, revealing novel correlations between them. These newfound insights into the interplay between cachexia, gut microbiota, and SCFAs provide a crucial foundation for understanding the mechanisms behind cancer cachexia development and potential therapeutic approaches.

Disordered gut microbiota and changes in short-chain fatty acids and inflammatory processes in stress-vulnerable mice

Long-term exposure to chronic stress increases the incidence of depression. However, chronic stress is an associated risk factor in only a subset of individuals. Inflammation has been identified as a putative mechanism promoting stress vulnerability. Because of the gut microbiota's potential role as a source of inflammatory substances, short-chain fatty acids (SCFAs) may exert their influence on inflammation, emotional states, and cognition via the gut-brain axis. In this study, Classic behavioral tests were used to categorize C57BL/6 J mice into a CUMS-vulnerable and a CUMS-resilient group after they were exposed to chronic unpredictable mild stress (CUMS). We compared the 16S ribosomal RNA (rRNA) gene sequences retrieved from fecal samples between control, CUMS-vulnerable, and CUMS-resilient mice. SCFAs in fecal samples were detected by liquid chromatography and gas chromatography–mass spectrometry. Hippocampal cytokine production and TLR4/MYD88/NF-κB inflammatory pathway activation were evaluated using enzyme-linked immunosorbent assays (ELISAs) and western blotting. Then, we supplemented SCFAs in CUMS mice. we observed depression-like behavior and the expression of TLR4/MYD88/NF-κB inflammatory pathway in hippocampus of SCFAs supplementation mice. Susceptible mice to CUMS showed more severe symptoms of depression and anxiety, α diversity was significantly different, as well as higher expression of interleukin (IL)-1β and TLR4/MYD88/NF-κB inflammatory pathway components in the hippocampus. SCFA levels in the feces were significantly higher in CUMS-resilient mice than in control mice. Depressive behavior was reversed in CUMS-SCFAs group, and the protein level of TLR4/MYD88/NF-κB in hippocampus was decreased. Overall, these results provide new light on the possible involvement of the microbiome in the gut-brain axis development in depressive disorder and provide a theoretical basis for identifying novel therapeutic targets.

The Effects of Synbiotics on Dextran-Sodium-Sulfate-Induced Acute Colitis: The Impact of Chitosan Oligosaccharides on Endogenous/Exogenous Lactiplantibacillus plantarum.

In this work, Lactiplantibacillus plantarum (L. plantarum) isolated from mice feces (LP-M) and pickles (LP-P) were chosen as the endogenous and exogenous L. plantarum, respectively, which were separately combined with chitosan oligosaccharides (COS) to be synbiotics. The anti-inflammatory activity of LP-M, LP-P, COS, and the synbiotics was explored using dextran-sodium-sulfate (DSS)-induced acute colitis mice, as well as by comparing the synergistic effects of COS with LP-M or LP-P. The results revealed that L. plantarum, COS, and the synbiotics alleviated the symptoms of mice colitis and inhibited the changes in short-chain fatty acids (SCFAs), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-10, and myeloperoxidase (MPO) caused by DSS. In addition, the intervention of L. plantarum, COS, and the synbiotics increased the relative abundance of beneficial bacteria Muribaculaceae and Lactobacillus and suppressed the pathogenic bacteria Turicibacter and Escherichia-Shigella. There was no statistically difference between LP-M and the endogenous synbiotics on intestinal immunity and metabolism. However, the exogenous synbiotics improved SCFAs, inhibited the changes in cytokines and MPO activity, and restored the gut microbiota more effectively than exogenous L. plantarum LP-P. This indicated that the anti-inflammatory activity of exogenous LP-P can be increased by combining it with COS as a synbiotic.

Study on the Hepatoprotective Effect Mechanism of Polysaccharides from Charred Angelica sinensis on the Layer Chickens Based on the Detection of the Intestinal Floras and Short-Chain Fatty Acids of Cecal Contents and Association Analysis.

To analyze the intervention mechanism of polysaccharides from charred Angelica sinensis (CASP) on the liver injury caused by Ceftiofur sodium (CS) and lipopolysaccharide (LPS) from the perspective of the intestine. Ninety-four one-day-old laying chickens underwent free feeding and drinking water for three days. Then, fourteen laying chickens were randomly selected as the control group, and sixteen laying chickens were selected as the model group. Sixteen laying chickens in the rest were randomly selected as the intervention group of CASP. Chickens in the intervention group were given CASP by the oral administration (0.25 g/kg/d) for 10 days, the control and model groups were given the same amount of physiological saline. During the 8th and 10th days, laying chickens in the model and CASP intervention group were subcutaneously injected with CS at the neck. In contrast, those in the control group were subcutaneously injected with the same amount of normal saline simultaneously. Except for the control group, the layer chickens in the model and CASP intervention groups were injected with LPS after CS injection on the 10th day of the experiment. In contrast, those in the control group were injected with the same amount of normal saline at the same time. 48 h after the experiment, the liver samples of each group were collected, and the liver injury was analyzed by hematoxylin-eosin (HE) staining and transmission electron microscopy. And the cecum contents of six-layer chickens in each group were collected, and the intervention mechanism of CASP on the liver injury from the perspective of the intestine was analyzed by the 16S rDNA amplicon sequencing technology and the short-chain fatty acids (SCFAs) detection of cecal contents based on Gas Chromatography-Mass Spectrometry (GC-MS), and their association analysis was carried out. The results showed that the structure of chicken liver in the normal control group was normal, while that in the model group was damaged. The structure of chicken liver in the CASP intervention group was similar to the normal control group. The intestinal floras in the model group were maladjusted compared to the normal control group. After the intervention of CASP, the diversity, and richness of chicken intestinal floras changed significantly. It was speculated that the intervention mechanism of CASP on the chicken liver injury might be related to the abundance and proportion of Bacteroidetes and Firmicutes. Compared with the model group, the indexes of ace, chao1, observed species, and PD whole tree of chicken cecum floras in the intervention group of CASP were significantly increased (p < 0.05). The contents of acetic acid, butyric acid, and total SCFAs in the intervention group of CASP were significantly lower than those in the model group (p < 0.05), and the contents of propionic acid and valeric acid in the intervention group of CASP were significantly lower than those in the model group (p < 0.05) and normal control group (p < 0.05). The correlation analysis showed that the changes in the intestinal floras were correlated with the changes in SCFAs in the cecum. It is confirmed that the liver-protecting effect of CASP is indeed related to the changes in the intestinal floras and SCFAs content in the cecum, which provides a basis for screening liver-protecting alternative antibiotics products for poultry.

Effects of compound prebiotics as prophylactic and therapeutic supplementation in a mouse model of acute colitis.

Compound prebiotics (CP) have been explored in modulation of intestinal microbiota and remission of inflammatory responses in the acute colitis (AC). Yet, research on the roles of simultaneous prophylactic and therapeutic CP intervention in relation to AC remains lacking. Here, CP were pre-fed to examine preventive effects. CP, CP combined with mesalazine (5-aminosalicylic acid) (CPM), and mesalazine were used to evaluate therapeutic effects on the dextran sulfate sodium (DSS)-induced AC. Results showed that prophylactic CP and therapeutic CPM alleviated AC, evidenced by variations of body weight, colon length, spleen index, disease activity index score, histological score, and intestinal mucosa. Ruminococcus and Bifidobacterium were detected in significant abundance in the prophylactic CP and therapeutic CPM groups, respectively. Phylogenetic ecological network analysis revealed that therapeutic CPM probably had the strongest coupling between microbes in changing intestinal microbiota to influence treatment. However, changes in short-chain fatty acids (SCFAs) seemed to have no persuasive results, probably due to reduced SCFA level in feces and variability in transit, absorption, and utilization. Furthermore, therapeutic CP exerted higher value in terms of observed species and Shannon diversity, as well as a more concentrated distribution by principal coordinates analysis. Together, the favorable roles of CP in colitis provide directions for prebiotics in designing effective prophylactic functional diets and treatment strategies. KEY POINTS: • Prebiotics as prophylactic intervention effectively inhibited acute colitis. • Prebiotics as prophylactic and therapeutic interventions had distinct effects on gut microbiota. • Prebiotics combined with drug intervention had higher efficacy in treating acute colitis.

Inulin from Dioscorea esculenta and Metformin in Combination Ameliorates Metabolic Syndrome in Rats by Altering Short-Chain Fatty Acids

Metabolic syndrome (MetS) increases the risk of diabetes and cardiovascular diseases. Several studies have highlighted the role of inulin and metformin in metabolic disorders since insulin resistance and gut microbiota are known to play a role in them. This study was aimed at assessing the effect of the combination of inulin from Dioscorea esculenta (DC) and metformin on insulin resistance, lipid profile, and short-chain fatty acids (SCFAs) in the MetS rat model. Twenty-five rats were divided into 5 groups consisting of one untreated group and four treated groups that received a single dose of streptozotocin (STZ) and a high-fat diet (HFD) for 35 days to induce MetS. Starting on day 14, three of the treated groups; I, M, and Com were administered inulin DC (360 mg/day, orally), metformin (100 mg/KgBW, intraperitoneally), and a combination of inulin DC and metformin (inulin DC; 360 mg/day, orally and metformin; 100 mg/KgBW, intraperioteneally), respectively. The biochemical parameters (HOMA-IR, serum insulin, glucose, HbA1C, cholesterol, triglyceride (TG), low-density lipoprotein (LDL) and SCFAs (butyric acid (BA), propionic acid (PA), and acetic acid (AA)) were evaluated. This study found that the combination of inulin DC and metformin decreased HOMA-IR, serum insulin, glucose, HbA1C, cholesterol, TG, LDL and increased butyric acid and propionic acid but not acetic acid in MetS model. In conclusion, the combination of inulin DC and metformin ameliorates insulin resistance and the lipid profile in MetS model rats was associated with the changes in SCFAs.

The Efficacy and Mechanism of Qinghua Jianpi Recipe in Inhibiting Canceration of Colorectal Adenoma Based on Inflammatory Cancer Transformation.

This study is aimed at exploring the effect of Qinghua Jianpi Recipe on preventing colon polyp recurrence and inhibiting the progress of "inflammatory cancer transformation." And another goal is to explore the changes of intestinal flora structure and intestinal inflammatory (immune) microenvironment of mice with colon polyps treated by Qinghua Jianpi Recipe and to clarify its mechanism. Clinical trials were conducted to confirm the therapeutic effect of Qinghua Jianpi Recipe on patients with inflammatory bowel disease. The inhibitory effect of Qinghua Jianpi Recipe on "inflammatory cancer transformation" of colon cancer was confirmed by an adenoma canceration mouse model. Histopathological examination was used to evaluate the effects of Qinghua Jianpi Recipe on intestinal inflammatory state, adenoma number, and pathological changes of adenoma model mice. The changes of inflammatory indexes in intestinal tissue were tested by ELISA. Intestinal flora was detected by 16S rRNA high-throughput sequencing. Short-chain fatty acid metabolism in the intestine was analyzed by targeted metabolomics. Network pharmacology analysis of possible mechanism of Qinghua Jianpi Recipe on colorectal cancer was performed. Western blot was used to detect the protein expression of the related signaling pathways. Qinghua Jianpi Recipe can significantly improve intestinal inflammation status and function in patients with inflammatory bowel disease. Qinghua Jianpi Recipe could significantly improve the intestinal inflammatory activity and pathological damage of adenoma model mice and reduce the number of adenoma. Qinghua Jianpi Recipe significantly increased the levels of Peptostreptococcales_Tissierellales, NK4A214_group, Romboutsia, and other intestinal flora after intervention. Meanwhile, the treatment group of Qinghua Jianpi Recipe could reverse the changes of short-chain fatty acids. Network pharmacology analysis and experimental studies showed that Qinghua Jianpi Recipe inhibited the "inflammatory cancer transformation" of colon cancer by regulating intestinal barrier function-related proteins, inflammatory and immune-related signaling pathways, and free fatty acid receptor 2 (FFAR2). Qinghua Jianpi Recipe can improve the intestinal inflammatory activity and pathological damage of patient and adenoma cancer model mice. And its mechanism is related to the regulation of intestinal flora structure and abundance, short-chain fatty acid metabolism, intestinal barrier function, and inflammatory pathways.

Slight Changes in the Gut Microbiome in Early-stage Chronic Kidney Disease of Unknown Etiology.

Gut dysbiosis and changes in short-chain fatty acids (SCFAs) occur in end-stage chronic kidney disease (CKD); however, the degree of these changes in the gut microbiome and serum SCFA profiles in the early stages of CKD,‍ ‍particularly in‍ ‍CKD‍ ‍of unknown etiology (CKDu), is unclear. We herein investigated the gut microbiome and SCFA profiles of early-stage CKD patients (CKD stages 1-3) in a community in Khon Kaen Province, Thailand. Seventy-two parasite-free participants were distributed among a healthy control group (HC, n=18) and three patient groups (an underlying disease group [UD, n=18], early-stage CKD with underlying disease [CKD-UD, n=18], and early-stage CKD of unknown etiology, [CKDu, n=18]). Fecal DNA was individually extracted and pooled for groups of six individuals (three pools in each group) to examine the composition of the gut microbiome using next-generation sequencing. A SCFA ana-lysis was performed on serum samples from each individual using gas chromatography-mass spectrometry. The results revealed that microbial abundance differed between the healthy group and all patient groups (UD, CKD-UD, and CKDu). [Eubacterium]_coprostanoligenes_group was more abundant in the CKDu group than in the HC and CKD-UD groups. Furthermore, serum concentrations of acetate, a major SCFA component, were significantly lower in all patient groups than in the HC group. The present results indicate that minor changes in the gut microbiome and a significant decrease in serum acetate concentrations occur in early-stage CKDu, which may be important for the development of prevention strategies for CKD patients.

The fate of mamaku gum in the gut: effect on in vitro gastrointestinal function and colon fermentation by human faecal microbiota.

Mamaku is a fern indigenous to the Pacific Islands with a long history of use for therapeutic benefits such as to combat skin conditions and manage gastrointestinal discomfort; however, the scientific understanding is limited. In this study, we examined the effect of mamaku gum, extracted from different age fronds of the New Zealand Black tree fern (Cyathea medullaris, Mamaku) (stage 1: young, stage 2: fully grown and stage 3: old), on gut function using in vitro models of static digestion, enzyme activity and static colonic fermentation. Under simulated gastric and small intestinal conditions, mamaku polysaccharide (MP) was indigestible as there was no decrease in the molecular weight (Mw) of the polymer. Mamaku gum could reduce the activity of digestive enzymes (α-amylase, pepsin and lipase) in a concentration-dependent manner, with the stage 1 sample showing the highest inhibition and stage 3 the lowest. All three mamaku gum samples could also equally bind bile acids during intestinal digestion. During fermentation, human faecal microbiota utilised the mamaku gum and significantly increased the production of total short-chain fatty acids (SCFAs) and reduced the pH when compared with the blank. However, changes in SCFAs and pH for mamaku groups were less prominent than for inulin and guar gum control groups, suggesting lower fermentability of mamaku gum compared to the latter two. Furthermore, mamaku gum altered the composition of colonic microbiota, specifically reducing the ratio of Firmicutes to Bacteroidetes and increasing the relative abundance of Bacteroides, Enterococcus, Paraprevotella and Parabacteroides genera. No obvious difference between mamaku gum samples from stage 1, 2 and 3 was observed during fermentation. Collectively, these results suggest that mamaku gum may modulate the functionality of the host gut by reducing enzyme activity, binding bile acids, altering the colonic microbial composition and producing SCFAs.

In vitro fermentation of fructooligosaccharide and galactooligosaccharide and their effects on gut microbiota and SCFAs in infants

• Gut microbes can degrade FOS and GOS to produce SCFAs and lactate. • The change of intestinal flora were the main factors affecting SCFAs accumulation. • The abundance of CAZymes was significantly higher in the GOS and FOS + GOS groups. • FOS and GOS may increase beneficial microbes and inhibit harmful microbes. Oligosaccharides are widely added to infant formula milk powders as prebiotics for intestinal health. Using in vitro fermentation conditions, this study investigated the fermentation characteristics of fructooligosaccharides (FOS) and galactooligosaccharides (GOS) with infant fecal inoculum. The changes in short-chain fatty acids (SCFAs) and lactate production were monitored by HPLC. The contents of SCFAs and lactate increased significantly in the GOS and FOS + GOS groups. Furthermore, the metagenomic analysis revealed that microbial communities were distinctively different. Most bacteria were significantly positively correlated with SCFAs production and negatively correlated with pH, particularly Bifidobacterium , Enterococcus , Weissella and Streptococcus . More importantly, the relative abundance of most carbohydrate-active enzymes (CAZymes, EC:2.3.1.54, EC:2.3.1.9 and EC:2.8.3.8, etc.) were significantly higher in the GOS and FOS + GOS groups. These results suggested that FOS and GOS had a significant regulatory effect on the composition and metabolism of the intestinal microbiota, further promoting the production of SCFAs and lactate.

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.

Healthy dietary choices are associated with higher serum propionate and PGC1α expression in peripheral blood mononuclear cells in adult humans

Obesity is a preventable multifactorial condition with negative risks to health. Gut microbiota can potentially affect host body weight through their mediators, as short-chain fatty acids (SCFAs) and lipopolysaccharide (LPS). To assess the diet-associated changes in SCFAs, LPS and related downstream mediators, peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC1α) and hypoxia-inducible factor 1 alpha (HIF1α). We hypothesized that consumed diet might be corresponding to serum levels of SCFAs and LPS and accompanied with analogous changes in their downstream effectors. Dietary intake of 31 participants was evaluated using 24-h recall, food frequency questionnaire and a Mediterranean diet scale (MDS). Serum SCFAs and LPS levels were estimated using gas chromatography-mass spectrometry and ELISA, respectively. PGC1α and HIF1α gene expression in Peripheral Blood Mononuclear Cells was detected by Real time quantitative polymerase chain reaction. Lean subjects showed higher dietary-fiber intake, MDS scores, propionate levels, PGC1α and HIF1α expression (P < 0.05). Propionate levels were positively correlated with MDS scores (P < 0.05), daily fiber intake, and PGC1α mRNA (P < 0.01). Relative expression levels of PGC1α and HIF1α were positively correlated (P < 0.05). LPS levels were higher in subjects with obesity compared to lean subjects (P < 0.01) and positively correlated with daily fat intake (P < 0.05). Subjects consuming diet closer to Mediterranean diet had higher levels of serum propionate and PGC1α mRNA. Furthermore, the up-regulated expression of PGC1α and HIF1α might work together in favoring energy expenditure and reducing body weight. • Dietary intake of study subjects was assessed by 24-h dietary recall, FFQ and a Mediterranean Diet Scale (MDS). • SCFAs and LPS were measured in serum and gene expression of PGC1α and HIF1α was assessed in PBMCs. • Lean subjects showed higher fiber intake, MDS scores, propionate levels, PGC1α and HIF1α expression and lower serum LPS. • Subjects consuming diet that is closer to Mediterranean diet had higher levels of serum propionate and PGC1α mRNA.

1H-NMR Profiling of Short-Chain Fatty Acid Content from a Physiologically Accurate Gut-on-a-Chip Device.

It has been shown that short-chain fatty acids (SCFAs) produced by the gut microbiome are of importance to host tissue health; however, measuring such compounds in biological samples is often limited to using hours to days old fecal and blood plasma samples. Organ-on-a-chip models have been created to simplify the complexity but struggle to reproduce the full biology of the gut specifically. We recently reported a tissue-in-a-chip gut model that incorporates gut explanted tissue into a microfluidic device. The system maintains a biologically relevant oxygen gradient and tissue ex vivo for days at a time, but minimal characterization of biological activity was reported. Herein, we use 1H-NMR to analyze the SCFA content of tissue media effluents from gut explants cultured in the recently developed microfluidic organotypic device (MOD). 1H-NMR can identify key SCFAs in the complex samples with minimal sample preparation. Our findings show that maintaining physiologically relevant oxygen conditions, something often missing from many other culture systems, significantly impacts the SCFA profile. Additionally, we noted the changes in SCFAs with culture time and potential variability between SCFA levels in male and female mouse tissue explants cultured in the MOD system based on 1H-NMR spectral profiles.