Metabolism Of Short-chain Fatty Acids Research Articles

Effect of a high-collagen peptide diet on the gut microbiota and short-chain fatty acid metabolism

Abstract In this study, a total of 24 male Sprague Dawley rats were randomly divided into 3 group (Collagen peptide of Salmon salar skin group, Ss-SCP; Collagen peptide of Tilapia nilotica skin group, Tn-SCP and Model control group, MC) to investigate the impact of a high-collagen peptide diet on the gut microbiota and host health. After 16 days intervention, the body weights of the Ss-SCP and Tn-SCP intervention groups were significantly increased and the liver index was also remarkably higher than that of the MC group. The acetic acid and propionic acid levels in feces were both significantly increased in the diet high-collagen peptide groups and valerate acid level was lower than that in the MC group. With the intervention of a high-dose collagen peptide diet, the gut microbiota of the groups was shifted with increased abundance of Lactobacillus, Unidentified-Prevotellaceae, Allobaculum, and Parasutterella, whereas the Tn-SCP administration have caused low abundance of Anaerostipes, Blautia, and Fusicatenibacter. The relative abundance of Allobaculum as well as Parasutterella was positively correlated with propionic acid and acetic acid levels, respectively. In addition, Allobaculum abundance was negatively correlated with valerate acid level. The serum valerate acid content was potentially harmful to rat health and significantly increased in the groups intervened with collagen peptide. All together, these results showed that administration of diet high-collagen peptide shifts the gut microbiota in rats and induced a disturbance in short-chain fatty acid metabolism which is potentially harmful to health.

Effects of a proinflammatory response on metabolic function of cultured, primary ruminal epithelial cells

Inflammation of ruminal epithelium may occur during ruminal acidosis as a result of translocation and interaction of ruminal epithelial cells (REC) with molecules such as lipopolysaccharide (LPS). Such inflammation has been reported to alter cellular processes such as nutrient absorption, metabolic regulation, and energy substrate utilization in other cell types but has not been investigated for REC. The objectives of this study were to investigate the effects of LPS on metabolism of short-chain fatty acids by primary REC, as well as investigating the effects of media containing short-chain fatty acids on the proinflammatory response. Ruminal papillae from 9 yearling Speckle Park beef heifers were used to isolate and culture primary REC. Cells were grown in minimum essential medium (MEM) for 12 d before use and then reseeded in 24-well culture plates. The study was conducted as a 2 × 2 factorial, where cells were grown in unaltered MEM (REG) or medium containing 2 mM butyrate and 5 mM propionate (SCFA) with (50,000 EU/mL; +LPS) or without LPS (-LPS) for 24 h. Supernatant samples were collected for analysis of glucose and SCFA consumption. Cells were collected to determine the expression of mRNA for genes associated with inflammation (TNF, IL1B, CXCL2, CXCL8, PTGS2, and TLR4), purinergic signaling (P2RX7, ADORAB2, and CD73), nutrient transport [SLC16A1 (MCT1), SLC16A3 (MCT4), SLC5A8, and MCU], and cell metabolism [ACAT1, SLC2A1 (GLUT1), IGFBP3, and IGFBP5]. Protein expression of TLR4 and ketogenic enzymes (BDH1 and HMGCS1) were also analyzed using flow cytometry. Statistical analysis was conducted with the MIXED model of SAS version 9.4 (SAS Institute Inc., Cary, NC) with medium, LPS exposure, and medium × LPS interaction as fixed effects and animal within plate as a random effect. Cells tended to consume more glucose when exposed to LPS as opposed to no LPS exposure (31.8 vs. 28.7 ± 2.7), but consumption of propionate and butyrate was not influenced by LPS. Expression of TNF and IL1B was upregulated when exposed to LPS, and expression of CXCL2 and CXCL8 increased following LPS exposure with SCFA (medium × LPS). For cells exposed to LPS, we found a downregulation of ACAT1 and IGFBP5 and an upregulation of SLC2A1, SLC16A3, MCU, and IGFBP3. Medium with SCFA led to greater expression of MCU. SLC16A1 was upregulated in cells incubated with SCFA and without LPS compared with the other groups. Protein expression of ketogenic enzymes was not affected; however, BDH1 mean fluorescence intensity (MFI) expression tended to be less in cells exposed to LPS. These data are interpreted to indicate that when REC are exposed to LPS, they may increase glucose metabolism. Moreover, transport of solutes was affected by SCFA in the medium and by exposure to LPS. Overall, the results suggest that metabolic function of REC in vitro is altered by a proinflammatory response, which may lead to a greater glucose requirement.

New strain of Pediococcus pentosaceus alleviates ethanol-induced liver injury by modulating the gut microbiota and short-chain fatty acid metabolism.

BACKGROUNDIntestinal dysbiosis has been shown to be associated with the pathogenesis of alcoholic liver disease (ALD), which includes changes in the microbiota composition and bacterial overgrowth, but an effective microbe-based therapy is lacking. Pediococcus pentosaceus (P. pentosaceus) CGMCC 7049 is a newly isolated strain of probiotic that has been shown to be resistant to ethanol and bile salts. However, further studies are needed to determine whether P. pentosaceus exerts a protective effect on ALD and to elucidate the potential mechanism.AIMTo evaluate the protective effect of the probiotic P. pentosaceus on ethanol-induced liver injury in mice.METHODSA new ethanol-resistant strain of P. pentosaceus CGMCC 7049 was isolated from healthy adults in our laboratory. The chronic plus binge model of experimental ALD was established to evaluate the protective effects. Twenty-eight C57BL/6 mice were randomly divided into three groups: The control group received a pair-fed control diet and oral gavage with sterile phosphate buffered saline, the EtOH group received a ten-day Lieber-DeCarli diet containing 5% ethanol and oral gavage with phosphate buffered saline, and the P. pentosaceus group received a 5% ethanol Lieber-DeCarli diet but was treated with P. pentosaceus. One dose of isocaloric maltose dextrin or ethanol was administered by oral gavage on day 11, and the mice were sacrificed nine hours later. Blood and tissue samples (liver and gut) were harvested to evaluate gut barrier function and liver injury-related parameters. Fresh cecal contents were collected, gas chromatography–mass spectrometry was used to measure short-chain fatty acid (SCFA) concentrations, and the microbiota composition was analyzed using 16S rRNA gene sequencing.RESULTSThe P. pentosaceus treatment improved ethanol-induced liver injury, with lower alanine aminotransferase, aspartate transaminase and triglyceride levels and decreased neutrophil infiltration. These changes were accompanied by decreased levels of endotoxin and inflammatory cytokines, including interleukin-5, tumor necrosis factor-α, granulocyte colony-stimulating factor, keratinocyte-derived protein chemokine, macrophage inflammatory protein-1α and monocyte chemoattractant protein-1. Ethanol feeding resulted in intestinal dysbiosis and gut barrier disruption, increased relative abundance of potentially pathogenic Escherichia and Staphylococcus, and the depletion of SCFA-producing bacteria, such as Prevotella, Faecalibacterium, and Clostridium. In contrast, P. pentosaceus administration increased the microbial diversity, restored the relative abundance of Lactobacillus, Pediococcus, Prevotella, Clostridium and Akkermansia and increased propionic acid and butyric acid production by modifying SCFA-producing bacteria. Furthermore, the levels of the tight junction protein ZO-1, mucin proteins (mucin [MUC]-1, MUC-2 and MUC-4) and the antimicrobial peptide Reg3β were increased after probiotic supplementation.CONCLUSIONBased on these results, the new strain of P. pentosaceus alleviated ethanol-induced liver injury by reversing gut microbiota dysbiosis, regulating intestinal SCFA metabolism, improving intestinal barrier function, and reducing circulating levels of endotoxin and proinflammatory cytokines and chemokines. Thus, this strain is a potential probiotic treatment for ALD.

Interactions between host genetics and gut microbiota determine susceptibility to CNS autoimmunity

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. The etiology of MS is multifactorial, with disease risk determined by genetics and environmental factors. An emerging risk factor for immune-mediated diseases is an imbalance in the gut microbiome. However, the identity of gut microbes associated with disease risk, their mechanisms of action, and the interactions with host genetics remain obscure. To address these questions, we utilized the principal autoimmune model of MS, experimental autoimmune encephalomyelitis (EAE), together with a genetically diverse mouse model representing 29 unique host genotypes, interrogated by microbiome sequencing and targeted microbiome manipulation. We identified specific gut bacteria and their metabolic functions associated with EAE susceptibility, implicating short-chain fatty acid metabolism as a key element conserved across multiple host genotypes. In parallel, we used a reductionist approach focused on two of the most disparate phenotypes identified in our screen. Manipulation of the gut microbiome by transplantation and cohousing demonstrated that transfer of these microbiomes into genetically identical hosts was sufficient to modulate EAE susceptibility and systemic metabolite profiles. Parallel bioinformatic approaches identified Lactobacillus reuteri as a commensal species unexpectedly associated with exacerbation of EAE in a genetically susceptible host, which was functionally confirmed by bacterial isolation and commensal colonization studies. These results reveal complex interactions between host genetics and gut microbiota modulating susceptibility to CNS autoimmunity, providing insights into microbiome-directed strategies aimed at lowering the risk for autoimmune disease and underscoring the need to consider host genetics and baseline gut microbiome composition.

Microbiota and Diabetes Mellitus: Role of Lipid Mediators

Diabetes Mellitus (DM) is an inflammatory clinical entity with different mechanisms involved in its physiopathology. Among these, the dysfunction of the gut microbiota stands out. Currently, it is understood that lipid products derived from the gut microbiota are capable of interacting with cells from the immune system and have an immunomodulatory effect. In the presence of dysbiosis, the concentration of lipopolysaccharides (LPS) increases, favoring damage to the intestinal barrier. Furthermore, a pro-inflammatory environment prevails, and a state of insulin resistance and hyperglycemia is present. Conversely, during eubiosis, the production of short-chain fatty acids (SCFA) is fundamental for the maintenance of the integrity of the intestinal barrier as well as for immunogenic tolerance and appetite/satiety perception, leading to a protective effect. Additionally, it has been demonstrated that alterations or dysregulation of the gut microbiota can be reversed by modifying the eating habits of the patients or with the administration of prebiotics, probiotics, and symbiotics. Similarly, different studies have demonstrated that drugs like Metformin are capable of modifying the composition of the gut microbiota, promoting changes in the biosynthesis of LPS, and the metabolism of SCFA.

Ruminal epithelial cell proliferation and short-chain fatty acid transporters in vitro are associated with abundance of period circadian regulator 2 (PER2)

The major circadian clock gene PER2 is closely related to cell proliferation and lipid metabolism in various nonruminant cell types. Objectives of the study were to evaluate circadian clock-related mRNA abundance in cultured goat ruminal epithelial cells (REC), and to determine effects of PER2 on cell proliferation and mRNA abundance of short-chain fatty acid (SCFA) transporters, genes associated with lipid metabolism, cell proliferation, and apoptosis. Ruminal epithelial cells were isolated from weaned Boer goats (n = 3; 2 mo old; ∼10 kg of body weight) by serial trypsin digestion and cultured at 37°C for 24 h. Abundance of CLOCK and PER2 proteins in cells was determined by immunofluorescence. The role of PER2 was assessed through the use of a knockout model with short interfering RNA, and sodium butyrate (15 mM) was used to assess the effect of upregulating PER2. Both CLOCK and PER2 were expressed in REC in vitro. Sodium butyrate stimulation increased mRNA and protein abundance of PER2 and PER3. Furthermore, PER2 gene silencing enhanced cell proliferation and reduced cellular apoptosis in isolated REC. In contrast, PER2 overexpression in response to sodium butyrate led to lower cellular proliferation and ratio of cells in the S phase along with greater ratio of cells in the G2/M phase. Those responses were accompanied by downregulated mRNA abundance of CCND1, CCNB1, CDK1, and CDK2. Among the SCFA transporters, PER2 silencing upregulated mRNA abundance of MCT1 and MCT4. However, it downregulated mRNA abundance of PPARA and PPARG. Overexpression of PER2 resulted in lower mRNA abundance of MCT1 and MCT4, and greater PPARA abundance. Overall, data suggest that CLOCK and PER2 might play a role in the control of cell proliferation, SCFA, and lipid metabolism. Further studies should be conducted to evaluate potential mechanistic relationships between circadian clock and SCFA absorption in vivo.

Understanding the mechanisms of efficacy of fecal microbiota transplant in treating recurrent Clostridioides difficile infection and beyond: the contribution of gut microbial-derived metabolites

ABSTRACT Fecal microbiota transplant (FMT) is a highly-effective therapy for recurrent Clostridioides difficile infection (rCDI), and shows promise for certain non-CDI indications. However, at present, its mechanisms of efficacy have remained poorly understood. Recent studies by our laboratory have noted the particular key importance of restoration of gut microbe-metabolite interactions in the ability of FMT to treat rCDI, including the impact of FMT upon short chain fatty acid (SCFAs) and bile acid metabolism. This includes a significant impact of these metabolites upon the life cycle of C. difficile directly, along with potential postulated additional benefits, including effects upon host immune response. In this Addendum, we first present an overview of these recent advancements in this field, and then describe additional novel data from our laboratory on the impact of FMT for rCDI upon several gut microbial-derived metabolites which had not previously been implicated as being of relevance.

Short-Chain Fatty Acids and Their Association with Signalling Pathways in Inflammation, Glucose and Lipid Metabolism.

Short-chain fatty acids (SCFAs), particularly acetate, propionate and butyrate, are mainly produced by anaerobic fermentation of gut microbes. SCFAs play an important role in regulating energy metabolism and energy supply, as well as maintaining the homeostasis of the intestinal environment. In recent years, many studies have shown that SCFAs demonstrate physiologically beneficial effects, and the signalling pathways related to SCFA production, absorption, metabolism, and intestinal effects have been discovered. Two major signalling pathways concerning SCFAs, G-protein-coupled receptors (GPRCs) and histone deacetylases (HDACs), are well recognized. In this review, we summarize the recent advances concerning the biological properties of SCFAs and the signalling pathways in inflammation and glucose and lipid metabolism.

Effects of Yu-Ping-Feng polysaccharides (YPS) on the immune response, intestinal microbiota, disease resistance and growth performance of Litopenaeus vannamei

A 28-day feeding trial was conducted to investigate the effects of Yu-Ping-Feng polysaccharides (YPS) containing Astragalus polysaccharides (APS), Atractylodes macrocephala polysaccharides (AMP) and Saposhnikoviae polysaccharides (SPS) on the immune response, intestinal microbiota, disease resistance and growth performance of Litopenaeus vannamei. Seven hundred and twenty shrimp (3.04 ± 0.33 g) were fed the following diets: Control, YPS1 (0.13% APS + 0.0325% AMP + 0.0325% SPS), YPS2 (0.13% APS + 0.0325% AMP + 0.065% SPS) and YPS3 (0.13% APS + 0.0325% AMP+0.0975% SPS). After 14 and 28 days of feeding, the immune responses of hemocytes and intestine were measured. Intestinal microbiota and growth performance were measured after 28 days of feeding, after that, a 7-day challenge test against Vibrio harveyi was conducted. A significant (P < 0.05) increase of the total haemocyte count (THC), phagocytic activity, antibacterial activity and phenoloxidase (PO) activity was observed in shrimp fed YPS diets compared to the control. Also, dietary YPS supplementation particularly YPS3 group significantly increased the expressions of immune-related genes in the hemocytes and intestine. Regarding the intestinal microbiota, the microbial diversity and richness decreased and functional genes associated with short-chain fatty acids metabolism increased in YPS groups. After Vibrio harveyi challenge, the cumulative mortality in YPS groups was significantly lower than that of the control. Besides, dietary YPS had no significant effect on growth performance of shrimp (P > 0.05). The present results suggested that YPS could be considered as potential prebiotics for aquaculture farmed shrimp.

Quantitative Differences in Interorgan Kinetics of Short-Chain Fatty Acids (SCFA)

Abstract Objectives The short-chain fatty acids (SCFA) acetate (C2), propionate (C3), butyrate (C4), isovalerate (Ci5), and valerate (C5) are endproducts of anaerobic fermentation by the intestinal microbiota and known to play a crucial role as energy source for colonocytes (C2 and C4) and muscle (C2), and as mediators in signaling pathways. To unravel the interorgan kinetics of SCFA, we measured their net balances across organs in a translational pig model. Methods In multi-catheterized conscious pigs (n = 11, 25.6 ± 2.2 kg), net balances across portal drained viscera (PDV), liver, kidney and hindquarter (HQ, muscle compartment) were measured in the postabsorptive state. Arterial and venous plasma (in μM) was collected and concentrations were measured by GC-MS. Data are mean (SE). Net balance in nmol/kg BW/min. Significance (P &amp;lt; 0.05) from zero was tested by Wilcoxon Signed Rank Test. Results In the postabsorptive state, arterial concentrations were C2: 189.1 (17.1), C3: 4.8 (0.3), C4: 7.1 (0.9), Ci5: 0.45 (0.09) and C5: 0.15 (0.03). A net release of C2 by PDV (8764 (527.5)) and liver resulted in a high splanchnic release (10,969 (1205)). PDV release of C3 was 2893 (353.9), of C4 1081 (175.9), of Ci5 133.7 (11.1), and of C5 271.2 (44.7). In contrast to C2, after extensive hepatic uptake, splanchnic release of C3, C4, Ci5, and C5 was only 6.5 (0.5)%, 39.3 (8.3)%, 26.3 (6.0)%, and 3.7 (0.9)% of the PDV release. All SCFA were taken up by HQ and kidney. However, while only 62% of C2 released by splanchnic compartment were taken up by muscle (hindquarter and forequarter) and kidneys, net uptake of C3, C4, Ci5 and C5 by muscle and kidney was comparable to splanchnic release. Conclusions Interorgan kinetics differ between C2 and the other SCFA. Due to differences in hepatic SCFA metabolism, acetate is the main SCFA in the systemic circulation possibly acting as energy source to muscle tissue, kidneys and organs or tissues not analyzed in this study. The liver controls the systemic concentrations of all other SCFA. Funding Sources Huffines Institute for Sports Medicine and Human Performance.

Bifidobacterium affected the correlation between gut microbial composition, SCFA metabolism, and immunity in mice with DNFB-induced atopic dermatitis

The prevalence of atopic dermatitis (AD) has increased and a therapeutic strategy using probiotic intervention has been reported. The effects of different Bifidobacterium (B. breve, B. bifidum, B. animalis, B. infants, and B. adolescentis) on gut microbial changes were explored in 2,4-dinitrofluorobenzene (DNFB)-induced AD, a T helper type 2-dominant allergic disease. Oral administration of Bifidobacterium suppressed skin thickening and mast cell infiltration, blocked pro-inflammatory cytokines (IL-4, CCL11, IL-13, and CCL22), increased IL-10 and IFN-γ, and modulated the microbiome and ecology in the gut. Based on 16S rRNA results, DNFB treatment resulted in gut microbial dysbiosis, characterized by a decrease in the proportion of Firmicutes and an increase in Bacteroidetes. The core microbiome related to AD were also observed (Dorea, Prevotella, Sutterella, Odoribacter, and Pseudomonas). B. breve and B. bifidum treatments increased the relative abundance of Adlercreutzia, Streptococcus, Lactobacillus, Anaerostipes, and Anaerotruncus. The functional modules involved in fructose and mannose metabolism, propanoate metabolism, and fatty acid biosynthesis were upregulated, and these might be related to immune regulation and short-chain fatty acids (SCFA) production. Taken together, these results suggested that Bifidobacterium treatments affected gut microbial composition and structure, altered gut microbial ecosystem, and these alterations were closely associated with inflammation and SCFA production.

Gut microbiota and metabolic syndrome.

Metabolic syndrome (MetS) describes a set of risk factors that can eventually lead to the occurrence of cardiovascular and cerebrovascular disease. A detailed understanding of the MetS mechanism will be helpful in developing effective prevention strategies and appropriate intervention tools. In this article, we discuss the relationship between the clinical symptoms of MetS and differences in the gut microbial community compared with healthy individuals, characterized by the proliferation of potentially harmful bacteria and the inhibition of beneficial ones. Interactions between gut microbiota and host metabolism have been shown to be mediated by a number of factors, including inflammation caused by gut barrier defects, short-chain fatty acids metabolism, and bile acid metabolism. However, although we can clearly establish a causal relationship between gut microbial profiles and MetS in animal experiments, the relationship between them is still controversial in humans. Therefore, we need more clinical studies to augment our understanding of how we can manipulate the gut microbiota and address the role of the gut microbiota in the prevention and treatment of MetS.

Altered Gut Microbiome Linked to Short Chain Fatty Acids Production in a Rat Model of Superimposed Preeclampsia

Preeclampsia (PE), a hypertensive disorder of pregnancy, is a leading cause of maternal and fetal morbidity. It affects 2–8% of all pregnancies, and its pathophysiology is not fully understood. Recent studies in preeclamptic patients have suggested a role for the gut microbiome (GM) in the disease. In addition, emerging evidence from both human and animal studies have reported that short‐chain fatty acids (SCFAs) and other gut‐derived metabolites such as lactate may modulate blood pressure (BP). We have characterized the Dahl salt‐sensitive (Dahl S) rat as a spontaneous rodent model of superimposed PE. The goal of our study was to determine if SCFAs production is impaired in PE. We hypothesized that preexisting chronic hypertension impairs maternal GM remodeling and maladaptation in SCFAs metabolism contributing to the development of superimposed PE. Female Sprague Dawley (SD) and Dahl S rats were maintained in conventional caging in the same room and on the same diet (Teklad 7034, 0.3% NaCl). Half of the rats of each strain were mated to have pregnant and virgin groups (n=7–9/group). Fecal samples were collected at baseline (BL), gestation day 20 (GD20) and one‐week postpartum (PP) to assess gut microbiome via 16S rRNA gene sequencing. Alpha diversity (Shannon index), beta diversity (Bray‐Curtis index), and linear discriminant analysis effect size (LEfSe) were determined from the sequenced data to assess microbial differences. PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states) was used to predict functional potential. At BL, Dahl S rats had higher alpha diversity (P&lt;0.0001) and distinctly clustered beta diversity (p&lt;0.001) compared to SD rats. Dahl S had higher Proteobacteria abundance (665,980 vs 51,240, p&lt;0.05), a marker of dysbiosis. In response to pregnancy, we observed significant differences among groups in both alpha and beta diversity during late pregnancy. Also, Proteobacteria abundance in the SD rats rose from 0.56% (BL) to 13.46% (GD20) before subsiding to 7.36% (PP) suggesting that these changes may be a normal adaptation to pregnancy. The Dahl S, however, showed no change in proteobacteria: 5.29% (BL) to 6.35% (GD20) and 7.8% (PP). We found Dahl S groups to have significantly lower abundance of genera such as Odoribacter and Roseburia which are known to produce butyrate, a SCFA associated with lowering BP, compared to the SD rats. On the other hand, Dahl S rats were significantly enriched in lactate producing genera including Turibacter and Streptococcus. Increased lactate producers have been previously associated with increased BP. In addition, when comparing each pregnant group to its virgin counterpart of the same strain, we found that Dahl S rats had differentially regulated butanoate (33 hits, p=0.01 vs. 32 hits, p=0.43) and propanoate (31 hits, p=0.01 vs. 29 hits, p=0.57) metabolic pathways but not in SD groups. Altogether, these data suggest that superimposed PE may be associated with impaired pregnancy‐specific GM changes and dysregulation in SCFAs production. Future studies will assess the therapeutic potential of beneficial SCFAs supplementation for the treatment of PE in this model.Support or Funding InformationR01HL134711 ( J. M. Sasser) &amp; funds to UMMC Molecular and Genomics Facility

Post-mortem tissue analyses in a patient with succinic semialdehyde dehydrogenase deficiency (SSADHD). I. Metabolomic outcomes.

Metabolomic characterization of post-mortem tissues (frontal and parietal cortices, pons, cerebellum, hippocampus, cerebral cortex, liver and kidney) derived from a 37 y.o. male patient with succinic semialdehyde dehydrogenase deficiency (SSADHD) was performed in conjunction with four parallel series of control tissues. Amino acids, acylcarnitines, guanidino- species (guanidinoacetic acid, creatine, creatinine) and GABA-related intermediates were quantified using UPLC and mass spectrometric methods that included isotopically labeled internal standards. Amino acid analyses revealed significant elevation of aspartic acid and depletion of glutamine in patient tissues. Evidence for disruption of short-chain fatty acid metabolism, manifest as altered C4OH, C5, C5:1, C5DC (dicarboxylic) and C12OH carnitines, was observed. Creatine and guanidinoacetic acids were decreased and elevated, respectively. GABA-associated metabolites (total GABA, γ-hydroxybutyric acid, succinic semialdehyde, 4-guanidinobutyrate, 4,5-dihydroxyhexanoic acid and homocarnosine) were significantly increased in patient tissues, including liver and kidney. The data support disruption of fat, creatine and amino acid metabolism as a component of the pathophysiology of SSADHD, and underscore the observation that metabolites measured in patient physiological fluids provide an unreliable reflection of brain metabolism.

Effect of Berberine on Atherosclerosis and Gut Microbiota Modulation and Their Correlation in High-Fat Diet-Fed ApoE-/- Mice.

Atherosclerosis and its associated cardiovascular diseases (CVDs) are serious threats to human health and have been reported to be associated with the gut microbiota. Recently, the role of berberine (BBR) in atherosclerosis and gut microbiota has begun to be appreciated. The purposes of this study were to observe the effects of high or low doses of BBR on atherosclerosis and gut microbiota modulation, and to explore their correlation in ApoE–/– mice fed a high-fat diet. A significant decrease in atherosclerotic lesions was observed after treatment with BBR, with the effect of the high dose being more obvious. Both BBR treatments significantly reduced total cholesterol, APOB100, and very low-density lipoprotein cholesterol levels but levels of high/low-density lipoprotein cholesterol and lipoprotein (a) were only reduced by high-dose BBR. Decreased pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6 and increased anti-inflammatory IL-10 and adiponectin levels were observed in the high-dose BBR group, but no decrease in IL-6 or increase in IL-10 was evident using the low-dose of BBR. 16S rRNA sequencing showed that BBR significantly altered the community compositional structure of gut microbiota. Specifically, BBR enriched the abundance of Roseburia, Blautia, Allobaculum, Alistipes, and Turicibacter, and changed the abundance of Bilophila. These microbiota displayed good anti-inflammatory effects related to the production of short-chain fatty acids (SCFAs) and were related to glucolipid metabolism. Alistipes and Roseburia were significantly enriched in high-dose BBR group while Blautia and Allobaculum were more enriched in low-dose, and Turicibacter was enriched in both BBR doses. Metagenomic analysis further showed an elevated potential for lipid and glycan metabolism and synthesis of SCFAs, as well as reduced potential of TMAO production after BBR treatment. The findings demonstrate that both high and low-dose BBR can improve serum lipid and systemic inflammation levels, and alleviate atherosclerosis induced by high-fat diet in ApoE–/– mice. The effects are more pronounced for the high dose. This anti-atherosclerotic effect of BBR may be partly attributed to changes in composition and functions of gut microbiota which may be associated with anti-inflammatory and metabolism of glucose and lipid. Notably, gut microbiota alterations showed different sensitivity to BBR dose.

Clinical translation of 18F-fluoropivalate \u2013 a PET tracer for imaging short-chain fatty acid metabolism: safety, biodistribution, and dosimetry in fed and fasted healthy volunteers

BackgroundFatty acids derived de novo or taken up from the extracellular space are an essential source of nutrient for cell growth and proliferation. Radiopharmaceuticals including 11C-acetate, and 18F-FAC (2-18F-fluoroacetate), have previously been used to study short-chain fatty acid (SCFA) metabolism. We developed 18F-fluoropivalate (18F-FPIA; 3-18F-fluoro-2,2-dimethylpropionic acid) bearing a gem-dimethyl substituent to assert metabolic stability for studying SCFA metabolism. We report the safety, biodistribution, and internal radiation dosimetry profile of 18F-FPIA in 24 healthy volunteers and the effect of dietary conditions.Materials and methodsHealthy volunteer male and female subjects were enrolled (n = 24), and grouped into 12 fed and 12 fasted. Non-esterified fatty acids (NEFA) and carnitine blood measurements were assessed. Subjects received 159.48 MBq (range, 47.31–164.66 MBq) of 18F-FPIA. Radiochemical purity was > 99%. Safety data were obtained during and 24 h after radiotracer administration. Subjects underwent detailed multiple whole-body PET/CT scanning with sampling of venous bloods for radioactivity and radioactive metabolite quantification. Regions of interest were defined to derive individual and mean organ residence times; effective dose was calculated using OLINDA 1.1.ResultsAll subjects tolerated 18F-FPIA with no adverse events. Over 90% of radiotracer was present in plasma at 60 min post-injection. The organs receiving highest absorbed dose (in mGy/MBq) were the liver (0.070 ± 0.023), kidneys (0.043 ± 0.013), gallbladder wall (0.026 ± 0.003), and urinary bladder (0.021 ± 0.004); otherwise there was low tissue uptake. The calculated effective dose using mean organ residence times over all 24 subjects was 0.0154 mSv/MBq (SD ± 0.0010). No differences in biodistribution or dosimetry were seen in fed and fasted subjects, though systemic NEFA and carnitine levels reflected fasted and fed states.ConclusionThe favourable safety, imaging, and dosimetric profile makes 18F-FPIA a promising candidate radiotracer for tracing SCFA metabolism.

Continuous biogas production from sugarcane as sole substrate

A German–Brazilian research project investigates sugarcane as an energy plant in anaerobic digestion for biogas production. The aim of the project is a continuous, efficient, and stable biogas process with sugarcane as the substrate. Tests are carried out in a fermenter with a volume of 10 l.In order to optimize the space–time load to achieve a stable process, a continuous process in laboratory scale has been devised. The daily feed in quantity and the harvest time of the substrate sugarcane has been varied. Analyses of the digester content were conducted twice per week to monitor the process: The ratio of inorganic carbon content to volatile organic acid content (VFA/TAC), the concentration of short-chain fatty acids, the organic dry matter, the pH value, and the total nitrogen, phosphate, and ammonium concentrations were monitored. In addition, the gas quality (the percentages of CO2, CH4, and H2) and the quantity of the produced gas were analyzed.The investigations have exhibited feasible and economical production of biogas in a continuous process with energy cane as substrate. With a daily feeding rate of 1.68 gVS /l*d the average specific gas formation rate was 0.5 m3/kgVS. The long-term study demonstrates a surprisingly fast metabolism of short-chain fatty acids. This indicates a stable and less susceptible process compared to other substrates.

P003 Metabolomics for improved patient stratification in inflammatory bowel disease: Characterisation of the ulcerative colitis metabolome

Abstract Background The onset of ulcerative colitis (UC) is characterised by a dysregulated mucosal immune response triggered by several genetic and environmental factors in the context of host-microbe interaction. This complexity makes UC ideal for metabolomic studies to unravel the disease pathobiology and to improve the patient stratification strategies toward personalised medicine. This study aims to explore the mucosal metabolomic profile in treatment-naïve and deep remission UC patients, and to define the metabolic signature of UC. Methods Treatment-naive UC patients (n = 18), UC patients in deep remission (n = 10), and healthy volunteers (n = 14) were recruited. Mucosa biopsies were collected during colonoscopy. The UC activity and the state of deep remission were assessed by endoscopy, histology, and by measuring TNF gene expression. Metabolomic analysis was performed by combined gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS) and ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS). In total, 177 metabolites from 50 metabolic pathways were identified. Results Multivariate data analysis revealed a distinct metabolomic profile in inflamed mucosa taken from treatment- naïve UC patients compared with non-inflamed mucosa taken from UC remission patients and healthy controls. The mucosal metabolome in UC remission patients differed to a lesser extent from the healthy controls. The most prominent metabolome changes among the study groups were in lysophosphatidylcholine, acylcarnitine, and amino acid profiles. Several metabolic pathways were perturbed, ranging from amino acid metabolism (such as tryptophan metabolism, and alanine, aspartate and glutamate metabolism) to antioxidant defence pathway (glutathione pathway). Furthermore, the pathway analysis revealed a disruption in the long-and short-chain fatty acid (LCFA and SCFA) metabolism, namely linoleic metabolism and butyrate metabolism. Conclusion The mucosal metabolomic profiling revealed a metabolic signature during the onset of UC, and reflected the homeostatic disturbance in the gut. The altered metabolic pathways highlight the importance of system biology approaches to identify key drivers of IBD pathogenesis which prerequisite personalised treatment.

Influence of the Mediterranean diet on the production of short-chain fatty acids in women at risk for breast cancer (LIBRE)

AbstractBackground: A number of small intervention studies suggested that a Mediterranean diet (MedD) and physical activity can lower the risk for breast cancer. LIBRE is the first large multicenter RCT to test the effect of these lifestyle factors on the incidence of breast cancer in women at risk because of BRCA mutations(1). LIBRE also offers to unravel underlying mechanisms such as the role of short-chain fatty acids (SCFA) for beneficial effects of such lifestyle interventions.Methods: We examined the effect of the lifestyle intervention on the production of SCFA measured in feces by gas chromatography. From the ongoing LIBRE trial we included all complete datasets (171 women; mean age 44 ± 11 years). Both women with and without previous breast cancer diagnosis were recruited (diseased; non-diseased). The participants were randomized into an intervention group (IG) trained for MedD and physical activity, and a usual care control group (CG). Adherence to the MedD was assessed at baseline and after 3 months (V1) using the validated Mediterranean Diet Adherence Screener (MEDAS) and the EPIC food frequency questionnaire (FFQ).Results: At baseline there was no difference in SCFA levels between the groups. In the IG the MEDAS score increased substantially by 2.5 points (p &lt; 0.001), in the CG only mildly by 0.4 points (p &lt; 0.05). Correspondingly, the intake of fibers increased solely in the IG. In the course of the study the amount of caproic acid decreased in the control group (p &lt; 0.001). At V1 non-diseased women showed higher amounts of acetic acid (p = 0.042), n-butyric acid (p = 0.023), n-valeric acid (p = 0.018) and iso-valeric acid (p = 0.031). There were several correlations between the intake of different fibers and fecal SCFA. For example, the sum of poly- and oligosaccharides correlated with acetic acid (p = 0.001; r = 0.316), propionic acid (p = 0.034; r = 0,251), n-butyric acid (p = 0.010; r = 0.316) and iso-valeric acid (p = 0.012; r = 0.306). There was no correlation between the MEDAS and SCFA.Discussion: A lifestyle change towards a MedD and increased physical activity did not change the levels of SCFA in feces, although an increase of fiber intake was documented in the IG. To further analyze SCFA metabolism in this target population, gut microbiota composition and function (metabolites) are currently analyzed.

L-Theanine affects intestinal mucosal immunity by regulating short-chain fatty acid metabolism under dietary fiber feeding.

To investigate the effects of l-Theanine (LTA) on intestinal mucosal immunity and the regulation of short-chain fatty acid (SCFA) metabolism under dietary fiber feeding, a 28-day feeding experiment was performed in Sprague-Dawley rats. The results show that LTA increased the proportion of Prevotella, Lachnospira, and Ruminococcus while increasing the total SCFA, acetic acid, propionic acid, and butyric acid contents in the feces. LTA also increased IgA, IgE, and IgG levels in the ileum, and increased villi height and crypt depth. Moreover, LTA upregulated the mRNA and protein expression of acetyl-CoA carboxylase 1, sterol element-binding protein 1c, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase in the liver, while downregulating the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon. Our study suggests that LTA can affect intestinal mucosal immunity by regulating SCFA metabolism under dietary fiber feeding.