Short-chain Fatty Acids Propionate Research Articles

The microbe-derived short-chain fatty acids butyrate and propionate are associated with protection from chronic GVHD

AbstractStudies of the relationship between the gastrointestinal microbiota and outcomes in allogeneic hematopoietic stem cell transplantation (allo-HCT) have thus far largely focused on early complications, predominantly infection and acute graft-versus-host disease (GVHD). We examined the potential relationship of the microbiome with chronic GVHD (cGVHD) by analyzing stool and plasma samples collected late after allo-HCT using a case-control study design. We found lower circulating concentrations of the microbe-derived short-chain fatty acids (SCFAs) propionate and butyrate in day 100 plasma samples from patients who developed cGVHD, compared with those who remained free of this complication, in the initial case-control cohort of transplant patients and in a further cross-sectional cohort from an independent transplant center. An additional cross-sectional patient cohort from a third transplant center was analyzed; however, serum (rather than plasma) was available, and the differences in SCFAs observed in the plasma samples were not recapitulated. In sum, our findings from the primary case-control cohort and 1 of 2 cross-sectional cohorts explored suggest that the gastrointestinal microbiome may exert immunomodulatory effects in allo-HCT patients at least in part due to control of systemic concentrations of microbe-derived SCFAs.

Exploring the Molecular Mechanisms Underlying the Protective Effects of Microbial SCFAs on Intestinal Tolerance and Food Allergy.

A body of evidence suggests that food allergy (FA) has increased in prevalence over the past few decades. Novel findings support the hypothesis that some commensal bacteria and particularly microbial metabolites might contribute to development of oral tolerance and prevention from FA. Recently, beneficial effects of short-chain fatty acids (SCFAs), the main class of gut microbiota-derived metabolites, on FA have been proposed. The intestinal SCFAs are major end products during bacterial fermentation of complex and non-digestible carbohydrates such as dietary fiber. The multifaceted mechanisms underlying beneficial effects of SCFAs on the mucosal immune system comprise the regulation of diverse cellular pathways in epithelial, dendritic, and T cells, as well as the impact on the immunometabolism and epigenetic status of regulatory lymphocytes. Of note, SCFAs are effective inhibitors of histone deacetylases (HDACs). As a consequence, SCFAs appear to be implicated in attenuation of intestinal inflammation and autoimmune diseases. In this review, we will discuss the recent development in this research area by highlighting the role of the individual SCFAs acetate, propionate, butyrate, and pentanoate in promoting the differentiation of regulatory T and B cells and their potential beneficial effects on the prevention of FA. In this context, targeted alterations in the gut microbiota in favor of SCFA producers or supplementation of medicinal food enriched in SCFAs could be a novel therapeutic concept for FA.

Short-chain fatty acids as novel therapeutics for gestational diabetes.

Gestational diabetes mellitus (GDM) affects up to 16% of pregnant women and is associated with significant long-term health detriments for the mother and her offspring. Two central features of GDM are low-grade inflammation and maternal peripheral insulin resistance, therefore therapeutics which target these may be most effective at preventing the development of GDM. Short-chain fatty acids (SCFAs), such as butyrate and propionate, are metabolites produced from the fermentation of dietary fibre by intestinal microbiota. SCFAs possess anti-inflammatory, anti-obesity and anti-diabetic properties. Therefore, this study aimed to investigate the effect of SCFAs on inflammation and insulin signalling defects in an in vitro model of GDM. Human placenta, visceral adipose tissue (VAT) and s.c. adipose tissue (SAT) were stimulated with either the pro-inflammatory cytokine TNF or bacterial product lipopolysaccharide (LPS). The SCFAs butyrate and propionate blocked TNF- and LPS-induced mRNA expression and secretion of pro-inflammatory cytokines and chemokines in placenta, VAT and SAT. Primary human cells isolated from skeletal muscle were stimulated with TNF to assess the effect of SCFAs on inflammation-induced defects in the insulin signalling pathway. Butyrate and propionate were found to reverse TNF-induced increases in IRS-1 serine phosphorylation and decreases in glucose uptake. Butyrate and propionate exerted these effects by preventing ERK activation. Taken together, these results suggest that the SCFAs may be able to improve insulin sensitivity and prevent inflammation induced by sterile or bacterial inflammation. Future in vivo studies are warranted to investigate the efficacy and safety of SCFAs in preventing insulin resistance and inflammation associated with GDM.

Effects of Heat-Treated Probiotics and Short-Chain Fatty Acids on Jejunal Integrity and Fecal Microbiome in Rats with Massive Bowel Resection

Abstract Objectives Massive bowel resection and total parenteral nutrition (TPN) are the major factors to affect intestinal integrity and microbiome in patients with short bowel syndrome (SBS). Studies showed that dead probiotics, which have no ability to produce short-chain fatty acids (SCFAs) to nourish enterocytes, may have similar benefits as live probiotics in promoting intestinal health. The aim of this study was to compare the effects of live and heat-treated probiotics with or without SCFAs on jejunal integrity and fecal microbiome in TPN-supported SBS rats. Methods Male SD rats were performed with intestinal resection, from 10 cm distal to the ligament of the Treitz to 5 cm distal to the colon, for SBS induction and with intubation of the right jugular vein for TPN infusion. TPN was administered right after the surgeries (day 0); and oral distilled water, live or heat-treated Lactobacillus acidophilus and Bifidobacterium bifidum, or the combination of heat-treated probiotics and intravenous SCFAs (acetate, propionate and butyrate) were administered from day 1 to day 6 to the SBS rats. Healthy, orally fed rats with no surgery were included as controls. Results The results showed that SBS rats had malnutrition, anemia, and jejunal damage. In the jejunum of the SBS rats, the increased glucagon-like peptide-2 was further increased by the live probiotics; the increased 19 kDa caspase 3 was decreased by heat-treated bacteria; and the decreased claudin 4 and toll-like receptor-4 were increased by the combination treatment of heat-treated probiotics and SCFAs. The results of 16S metagenomic next-generation sequencing revealed that the SBS-decreased alpha-diversity and Firmicutes and the SBS-increased ratio of Firmicutes to Bacteroidetes were reversed by heat-treated bacteria; and the SBS-increased Proteobacteria and Actinobacteria were decreased by the live probiotics. The SBS-induced change in beta diversity was not altered by any treatment. Conclusions In conclusion, the combination treatment of heat-treated probiotics and SCFAs may improve jejunal integrity and the live and heat-treated probiotics may alter, at least partially, the bacterial diversity and distribution of the feces in SBS patients with TPN. Funding Sources MOST 105-2320-B-030-003-MY3.

Butyrate inhibits human mast cell activation via epigenetic regulation of FcεRI-mediated signaling.

Short-chain fatty acids (SCFAs) are fermented dietary components that regulate immune responses, promote colonic health, and suppress mast cell-mediated diseases. However, the effects of SCFAs on human mast cell function, including the underlying mechanisms, remain unclear. Here, we investigated the effects of the SCFAs (acetate, propionate, and butyrate) on mast cell-mediated pathology and human mast cell activation, including the molecular mechanisms involved. Precision-cut lung slices (PCLS) of allergen-exposed guinea pigs were used to assess the effects of butyrate on allergic airway contraction. Human and mouse mast cells were co-cultured with SCFAs and assessed for degranulation after IgE- or non-IgE-mediated stimulation. The underlying mechanisms involved were investigated using knockout mice, small molecule inhibitors/agonists, and genomics assays. Butyrate treatment inhibited allergen-induced histamine release and airway contraction in guinea pig PCLS. Propionate and butyrate, but not acetate, inhibited IgE- and non-IgE-mediated human or mouse mast cell degranulation in a concentration-dependent manner. Notably, these effects were independent of the stimulation of SCFA receptors GPR41, GPR43, or PPAR, but instead were associated with inhibition of histone deacetylases. Transcriptome analyses revealed butyrate-induced downregulation of the tyrosine kinases BTK, SYK, and LAT, critical transducers of FcεRI-mediated signals that are essential for mast cell activation. Epigenome analyses indicated that butyrate redistributed global histone acetylation in human mast cells, including significantly decreased acetylation at the BTK, SYK, and LAT promoter regions. Known health benefits of SCFAs in allergic disease can, at least in part, be explained by epigenetic suppression of human mast cell activation.

Abstract A12: Expression of GPR41, GPR43, and GPR109A in breast tissue in relation to breast cancer development

Abstract Introduction: There is evidence to suggest that the human microbiome may play a key role in the development of breast cancer. There is a unique microbial signature in mammary tissue that is associated with breast cancer. Further, there is mounting evidence to support the role of the gut microbiome in promoting or preventing breast cancer. Consequently, specific compositional and/or functional shifts in either of these microbiomes may promote the growth of breast tumors. Short chain fatty acids (SCFAs) are microbial metabolites produced in the large intestine by bacterial fermentation of complex carbohydrates. These metabolites exit the gut and interact with many different cell types throughout the human body, including those in the breast, via g-protein coupled receptors; GPR41, GPR43, and GPR109A. These metabolites have been identified as a potential functional connection between the gut microbiome and breast cancer but have not been studied in breast tissue in the context of breast cancer. To assess the interaction between the microbiome and breast tumor development, we analyzed the expression of these receptors in tissue collected from women who donated healthy, prediagnostic, or cancerous tissue to the Susan G. Komen and Indiana University Simon Cancer Center Tissue Banks. Methods: DNA and RNA (n=60, n = 15 for each tissue subset: healthy, prediagnostic, adjacent normal, and tumor tissue) was copurified from these tissues using the Qiagen AllPrep® PowerFecal® DNA/RNA Kit. The RNA was then reverse transcribed into complementary DNA. Quantitative PCR was performed on the cDNA using four validated primer sets: GPR41, GPR43, GPR109A, and ribosomal 18S (housekeeping gene). Results/Cconclusions: We did not identify any significant differences in expression levels of these receptors between the participant groups, suggesting that cancer status is not associated with increased metabolic activity of the microbiome. We are currently conducting sensitivity analyses to determine the role of clinical factors such as age, menopausal status, BMI, etc., on the expression of these receptors in breast tissue. We are also investigating the expression of enzymes and transporters in breast tissue related to host cell metabolism of the most bioactive SCFAs (acetate, propionate, and butyrate). This work will yield valuable information regarding the interaction between the human microbiome and breast tumor development. Ultimately, it may be possible to target SCFA-producing bacteria or SCFA catabolic pathways in breast tissue to prevent or treat breast cancer. Citation Format: Annie Kump, Daniel Herrera, Leah T. Stiemsma. Expression of GPR41, GPR43, and GPR109A in breast tissue in relation to breast cancer development [abstract]. In: Proceedings of the AACR Special Conference on the Microbiome, Viruses, and Cancer; 2020 Feb 21-24; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2020;80(8 Suppl):Abstract nr A12.

Nicotine exposure during pregnancy alters the maternal gut microbiome and both cecal and plasma short chain fatty acids in Sprague Dawley rats.

Children of mothers that smoke during pregnancy are more likely to be obese and develop high blood pressure, suggesting a developmental origin of these diseases. Evidence now suggests that an imbalance of the bacterial microbes in the gastrointestinal tract may also play an important role these diseases. Thus, the present study was undertaken to test the hypothesis that nicotine‐exposure during pregnancy alters the maternal gut‐microbiome, inducing gut dysbiosis that may be passed on to the child during birth and/or shifts in bacterial metabolites, such as short chain fatty acids (SCFAs), that the fetus is exposed to in utero. To test our hypothesis, age‐matched virgin and pregnant female rats were exposed to nicotine (6 mg/kg/day) or vehicle (saline) via osmotic mini pump, including days 6–18 of pregnancy. Cecal contents, tissue from the proximal colon, and plasma were collected on day 14 of treatment. A two‐way ANOVA (pregnant state x treatment) identified that pregnancy decreased the abundance of bacteria in the phyla Firmicutes, while increasing the abundance of Actinobacteria and Verrucomicrobia compared to virgin rats (P<0.02). Nicotine exposure, independent of pregnancy, further increased the abundance of Actinobacteria (P<0.03) and tended to increase the proportion of Firmicutes and decrease the abundance of Verrucomicrobia. Evaluation of cecal SCFAs identified that pregnancy upregulated the abundance of acetate and propionic acid (P<0.02) and tended to upregulate butyric and hexanoic acid. Conversely, nicotine exposure, independent of pregnancy, decreased cecal acetate (P<0.02), propionic acid (P<0.007), and hexanoic acid (P<0.009) concentrations. Similarly, plasma levels of acetate, propionic, butyric, and valeric acid were upregulated by pregnancy, and nicotine exposure, independent of pregnant state, reversed this trend (P<0.05). Finally, gene expression in the proximal colon identified that pregnancy triggered an upregulation of multiple genes, including the protective enzyme 11‐beta HSD2, the sodium channel ENAC, Ffar2, the SCFA acetate and propionate transporter, the solute carrier SMCT1, and Tph2, the rate limiting enzyme for serotonin production (P<0.05). Independent of pregnancy status, nicotine downregulated the expression of all five genes. These results confirm our hypothesis that nicotine exposure during pregnancy can significantly alter the maternal gut microbiome and affect fetal exposure to specific circulating factors linked to gut microbial metabolism. These findings provide a new link between changes in the maternal gut microbiome and the fetal origins of adult diseases.Support or Funding InformationFL DOH James and Esther King Biomedical Research Program 8JK06

The short-chain fatty acids butyrate and propionate protect against inflammation-induced activation of mediators involved in active labor: implications for preterm birth.

Spontaneous preterm birth is a global health issue affecting up to 20% of pregnancies and leaves a legacy of neurodevelopmental complications. Inflammation has been implicated in a significant proportion of preterm births, where pro-inflammatory insults trigger production of additional pro-inflammatory and pro-labor mediators. Thus, novel therapeutics that can target inflammation may be a novel avenue for preventing preterm birth and improving adverse fetal outcomes. Short-chain fatty acids (SCFAs), such as butyrate and propionate, are dietary metabolites produced by bacterial fermentation of fiber in the gut. SCFAs are known to possess anti-inflammatory properties and have been found to function through G-coupled-receptors and histone deacetylases. Therefore, this study aimed to investigate the effect of SCFAs on pro-inflammatory and pro-labor mediators in an in vitro model of preterm birth. Primary human cells isolated from myometrium and fetal membranes (decidua, amnion mesenchymal and amnion epithelial cells) were stimulated with the pro-inflammatory cytokines tumor necrosis factor alpha (TNF) or interleukin 1B (IL1B). The SCFAs butyrate and propionate suppressed inflammation-induced expression of pro-inflammatory cytokines and chemokines, adhesion molecules, the uterotonic prostaglandin PGF2alpha and enzymes involved in remodeling of myometrium and degradation of the fetal membranes. Notably, propionate and butyrate also suppressed inflammation-induced prostaglandin signaling and myometrial cell contraction. These effects appear to be mediated through suppression of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation. These results suggest that the SCFAs may be able to prevent myometrial contractions and rupture of membranes. Further in vivo studies are warranted to identify the efficacy of SCFAs as a novel anti-inflammatory therapeutic to prevent inflammation-induced spontaneous preterm birth.

Short-chain fatty acids as potential regulators of skeletal muscle metabolism and function.

A key metabolic activity of the gut microbiota is the fermentation of non-digestible carbohydrate, which generates short-chain fatty acids (SCFAs) as the principal end products. SCFAs are absorbed from the gut lumen and modulate host metabolic responses at different organ sites. Evidence suggests that these organ sites include skeletal muscle, the largest organ in humans, which plays a pivotal role in whole-body energy metabolism. In this Review, we evaluate the evidence indicating that SCFAs mediate metabolic cross-talk between the gut microbiota and skeletal muscle. We discuss the effects of three primary SCFAs (acetate, propionate and butyrate) on lipid, carbohydrate and protein metabolism in skeletal muscle, and we consider the potential mechanisms involved. Furthermore, we highlight the emerging roles of these gut-derived metabolites in skeletal muscle function and exercise capacity, present limitations in current knowledge and provide suggestions for future work.

The small chain fatty acid butyrate antagonizes the TCR-stimulation-induced metabolic shift in murine epidermal gamma delta T cells.

The metabolic requirements change during cell proliferation and differentiation. Upon antigen-stimulation, effector T cells switch from adenosine-triphospate (ATP)-production by oxidative phosphorylation in the mitochondria to glycolysis. In the gut it was shown that short chain fatty acids (SCFA), fermentation products of the microbiota in colon, ameliorate inflammatory reactions by supporting the differentiation of regulatory T cells. SCFA are a major energy source, but they are also anabolic metabolites, histone-deacetylase-inhibitors and activators of G protein receptors. Recently, it was reported that a topical application of the SCFA butyrate promotes regulatory T cells in the skin. Here we ask if the SCFA butyrate, propionate and acetate affect the energy metabolism and inflammatory potential of dendritic epidermal T cells (DETC), the innate resident skin γδ T cell population. Using the Seahorse™ technology, we measured glycolysis and oxidative phosphorylation (OXPHOS) in a murine DETC cell line, 7-17, upon TCR-stimulation by CD3/CD28 crosslinking, with or without SCFA addition. TCR engagement resulted in a change of the ratio glycolysis/OXPHOS. A similar metabolic shift has been described for activated CD4 T cells. Addition of 5 mM SCFA, in particular butyrate, antagonized the effect. Stimulated DETC secrete cytokines, e.g. the pro-inflammatory cytokine interferon-gamma (IFNγ), and thereby regulate skin homeostasis. Addition of butyrate and propionate to the cultures at non-toxic concentrations decreased secretion of IFNγ by DETC and increased the expression of the immunoregulatory surface receptor CD69. We hypothesize that SCFA can dampen the inflammatory activity of DETC.

Propionate supplementation promotes the expansion of peripheral regulatory T-Cells in patients with end-stage renal disease

Patients with end-stage renal disease (ESRD) suffer from a progressively increasing low-grade systemic inflammation, which is associated with higher morbidity and mortality. Regulatory T cells (Tregs) play an important role in regulation of the inflammatory process. Previously, it has been demonstrated that short-chain fatty acids reduce inflammation in the central nervous system in a murine model of multiple sclerosis through an increase in tissue infiltrating Tregs. Here, we evaluated the effect of the short-chain fatty acid propionate on the chronic inflammatory state and T-cell composition in ESRD patients. Analyzing ESRD patients and healthy blood donors before, during, and 60 days after the propionate supplementation by multiparametric flow cytometry we observed a gradual and significant expansion in the frequencies of CD25highCD127− Tregs in both groups. Phenotypic characterization suggests that polarization of naïve T cells towards Tregs is responsible for the observed expansion. In line with this, we observed a significant reduction of inflammatory marker CRP under propionate supplementation. Of interest, the observed anti-inflammatory surroundings did not affect the protective pathogen-specific immunity as demonstrated by the stable frequencies of effector/memory T cells specific for tetanus/diphtheria recall antigens. Collectively, our data suggest that dietary supplements with propionate have a beneficial effect on the elevated systemic inflammation of ESRD patients. The effect can be achieved through an expansion of circulating Tregs without affecting the protective pathogen-reactive immunity.

Mouse mothers transfer metabolic mode

Microbiota Obesity and metabolic diseases tend to go together, and humans who become obese are also prone to type 2 diabetes and cardiovascular problems. Starting with the observation that offspring of germ-free mice tended to become obese on high-fat diets, Kimura et al. investigated how the presence of the microbiota might be protective in mice (see the Perspective by Ferguson). Short-chain fatty acids (SCFAs) from the microbiota are known to suppress insulin signaling and reduce fat deposition in adipocytes. Further experiments showed that SCFAs in the bloodstream were able to pass from a non–germ-free mother's gut microbiota across the placenta and into the developing embryos. The authors found that in the embryos, the SCFA propionate mediates not only insulin levels through GPR43 signaling but also sympathetic nervous system development through GPR41 signaling. A high-fiber diet promoted propionate production from the maternal microbiota, and maternal antibiotic treatment resulted in obese-prone offspring. Science , this issue p. [eaaw8429][1]; see also p. [978][2] [1]: /lookup/doi/10.1126/science.aaw8429 [2]: /lookup/doi/10.1126/science.aba7673

Maternal gut microbiota in pregnancy influences offspring metabolic phenotype in mice

Antibiotics and dietary habits can affect the gut microbial community, thus influencing disease susceptibility. Although the effect of microbiota on the postnatal environment has been well documented, much less is known regarding the impact of gut microbiota at the embryonic stage. Here we show that maternal microbiota shapes the metabolic system of offspring in mice. During pregnancy, short-chain fatty acids produced by the maternal microbiota dictate the differentiation of neural, intestinal, and pancreatic cells through embryonic GPR41 and GPR43. This developmental process helps maintain postnatal energy homeostasis, as evidenced by the fact that offspring from germ-free mothers are highly susceptible to metabolic syndrome, even when reared under conventional conditions. Thus, our findings elaborate on a link between the maternal gut environment and the developmental origin of metabolic syndrome.

Association between the faecal short-chain fatty acid propionate and infant sleep.

The gut microbiota harvests energy from indigestible plant polysaccharides, forming short-chain fatty acids (SCFAs) that are absorbed from the bowel. SCFAs provide energy-presumably after easily digested food components have been absorbed from the small intestine. Infant night waking is believed by many parents to be due to hunger. Our objective was to determine whether faecal SCFAs are associated with longer uninterrupted sleep in infants. Infants (n = 57) provided faecal samples for determining SCFAs (7 months of age), and questionnaire data for determining infant sleep (7 and 8 months). Linear regression determined associations between SCFAs-faecal acetate, propionate and butyrate-and sleep. For each 1% higher propionate at 7 months of age, the longest night sleep was 6 (95% CI: 1, 10) minutes longer at both 7 and 8 months. A higher proportion of total faecal SCFA as propionate was associated with longer uninterrupted infant sleep.

Using Precisely Defined in vivo Microbiotas to Understand Microbial Regulation of IgE.

Early life exposure to microbes plays an important role in immune system development. Germ-free mice, or mice colonized with a low-diversity microbiota, exhibit high serum IgE levels. An increase in microbial richness, providing it occurs in a critical developmental window early in life, leads to inhibition of this hygiene-induced IgE. However, whether this inhibition is dependent solely on certain microbial species, or is an additive effect of microbial richness, remains to be determined. Here we report that mice colonized with a combination of bacterial species with specific characteristics is required to inhibit IgE levels. These defined characteristics include the presence in early life, acetate production and immunogenicity reflected by induction of IgA. Suppression of IgE did not correlate with production of the short chain fatty acids propionate and butyrate, or induction of peripherally induced Tregs in mucosal tissues. Thus, inhibition of IgE induction can be mediated by specific microbes and their associated metabolic pathways and immunogenic properties.

Hepatic Metabolomic and Transcriptomic Responses Induced by Cecal Infusion of Sodium Propionate in a Fistula Pig Model.

Short-chain fatty acids (SCFAs) are the major products of the microbial fermentation of indigestible carbohydrates. SCFAs are known to improve the host metabolism, but their underlying mechanism of action remains elusive. In this study, 16 growing pigs were infused with saline or sodium propionate solution (25 mL, 2 mol/L) through a cecal fistula twice a day during a 28 day experimental period. The results showed that the cecal infusion of the SCFA propionate decreased serum and liver triglyceride levels and increased serum PYY secretion in growing pigs. Hepatic metabolomics identified 12 metabolites that were significantly altered by propionate. These included decreased levels of lipid metabolism-related stearic acid and glycerol-2-phosphate; increased levels of TCA cycle components including malic acid, fructose-6-phosphate, and succinic acid; and decreased levels of the amino acid metabolism products aspartic acid and serine. Hepatic transcriptomics demonstrated that propionate inhibited fatty acid synthesis and promoted the lipid metabolic process. Pathway enrichment analysis showed that propionate accelerated gluconeogenesis and decreased glycolysis. Taken together, these data support a role of the SCFA propionate on host lipid and glucose metabolism.

SCFAs-Induced GLP-1 Secretion Links the Regulation of Gut Microbiome on Hepatic Lipogenesis in Chickens.

The impact of gut microbiota and its metabolites on fat metabolism have been widely reported in human and animals. However, the critical mediators and the signal transductions are not well demonstrated. As ovipara, chicken represents a specific case in lipid metabolism that liver is the main site of lipid synthesis. The aim of this study is to elucidate the linkage of gut microbiota and fat synthesis in broiler chickens. The broilers were subjected to dietary treatments of combined probiotics (Animal bifidobacterium: 4 × 108 cfu/kg; Lactobacillus plantarum: 2 × 108 cfu/kg; Enterococcus faecalis: 2 × 108 cfu/kg; Clostridium butyrate: 2 × 108 cfu/kg, PB) and guar gum (1 g/kg, GG), respectively. Results showed that dietary supplementation of PB and GG changed the cecal microbiota diversity, altered short chain fatty acids (SCFAs) contents, and suppressed lipogenesis. In intestinal epithelial cells (IECs), SCFAs (acetate, propionate, and butyrate) up-regulated the expression of glucagon-like peptide-1 (GLP-1) via mitogen-activated protein kinase (MAPK) pathways, mainly via the phospho - extracellular regulated protein kinase (ERK) and phospho-p38 mitogen activated protein kinase (p38 MAPK) pathways. GLP-1 suppressed lipid accumulation in primary hepatocytes with the involvement of (AMP)-activated protein kinase/Acetyl CoA carboxylase (AMPK/ACC) signaling. In conclusion, the result suggests that SCFAs-induced GLP-1 secretion via MAPK pathway, which links the regulation of gut microbiota on hepatic lipogenesis in chickens.

Mixed Spices at Culinary Doses Have Prebiotic Effects in Healthy Adults: A Pilot Study

Spices were used as food preservatives prior to the advent of refrigeration, suggesting the possibility of effects on microbiota. Previous studies have shown prebiotic activities in animals and in vitro, but there has not been a demonstration of prebiotic or postbiotic effects at culinary doses in humans. In this randomized placebo-controlled study, we determined in twenty-nine healthy adults the effects on the gut microbiota of the consumption daily of capsules containing 5 g of mixed spices at culinary doses by comparison to a matched control group consuming a maltodextrin placebo capsule. The 16S ribosomal RNA sequencing data were used for microbial characterization. Spice consumption resulted in a significant reduction in Firmicutes abundance (p < 0.033) and a trend of enrichment in Bacteroidetes (p < 0.097) compared to placebo group. Twenty-six operational taxonomic units (OTUs) were different between the spice and placebo groups after intervention. Furthermore, there was a significant negative correlation between fecal short-chain fatty acid propionate concentration and Firmicutes abundance in spice intervention group (p < 0.04). The production of individual fecal short-chain fatty acid was not significantly changed by spice consumption in this study. Mixed spices consumption significantly modified gut microbiota, suggesting a prebiotic effect of spice consumption at culinary doses.

Fiber Type Determines Feline Gut Microbiome Metabolism and Bioactive Lipid Profiles in Feces (P20-034-19)

ObjectivesDietary fiber consists of indigestible carbohydrate. A distinction in fiber classification is “soluble” (SOL) vs “insoluble” (INSOL). Fiber is not absorbed in the small intestine, but arrives intact to the colon where it is metabolized by microbiota. Metabolomics screening determined the impact of foods with SOL vs INSOL fiber on microbiome metabolites and bioactive lipids in feces from cats. MethodsHealthy cats were housed in environments promoting social interaction with other cats and people, had access to natural light varying with season, opportunity to exercise and were fed to maintain body weight. Collections under IACUC approved protocols. Two foods produced: SOL (5.2% crude fiber analyzed) and INSOL (10.1% crude fiber analyzed). SOL had citrus & beet pulps, oat bran and barley. INSOL had pea & tomato fiber, and cellulose. Randomized design, with cats assigned SOL (n = 15), INSOL (n = 16). Cats fed for 12 weeks. Metabolomics by LC-MS, short chain fatty acids (SCFA) by GC-FID (feces). Data analyzed by mixed model, paired t-test, Hotelling’s T2 test and correlation. Significant when P < 0.05. ResultsSOL increased flavonoids in the feces, likely from fiber-bound sources; these were metabolized by gut microbiota to postbiotics. Only SOL increased SCFA acetate and propionate but not butyrate. INSOL decreased, and SOL increased putrefactive branched SCFA. Polyamine putrefaction products were decreased by INSOL relative to SOL; fecal polyamine levels predicted serum levels. Fecal microbial metabolites of resistant starch, polyphenols and redox congeners were all correlated to fecal taurine across both foods. INSOL significantly decreased the N-acyl classes of fecal endocannabinoids while leaving the O-acyl class unchanged. SOL increased the O-acyl class. Fecal anti-inflammatory fatty acid esters of hydroxystearate (FAHSA; linoleic, oleic and palmitic) were significantly increased by INSOL relative to SOL. Fecal 9/13 hydroxyoctadecadienoates (HODE) were increased by INSOL relative to SOL, but the 9–10/12–13 dihydroxyoctadecaenoates (DiHOME) were not affected. ConclusionsThere are apparent microbiome benefits to both SOL and INSOL fibers. The results here increase awareness of the importance of fiber for felines and further the effort to optimize fiber type and quantity in foods for cats. Funding SourcesHill’s Pet Nutrition.

738-P: Meta’omic Analysis of Elite Athletes Identifies a Performance-Enhancing Microbe that Functions via Lactate Metabolism

The human gut microbiome encodes a vast metabolic repertoire with direct impacts on many aspects of host physiology, yet it is unknown whether it has any bearing on physical performance or exercise. To begin to address this question, we performed a longitudinal metagenomic analysis on runners in the 2015 Boston Marathon to identify microbiome features associated with intense physical activity. The strongest microbiome feature enriched post-marathon was an increase in the abundance of the bacterial genus Veillonella. We isolated Veillonella atypica directly from the marathon runners, and found that upon inoculation in laboratory mice in an AB/BA crossover study testing treadmill runtime to exhaustion, runtime was increased 13% in a V. atypica-dependent manner. V. atypica has a preference for lactate as its primary carbon source, and we find using shotgun metagenomic analysis in a cohort of elite athletes that every differentially expressed gene family in the pathway metabolizing lactate to the short-chain fatty acid propionate is at higher relative abundance post-exercise. Using 13C3-labeled lactate in mice we demonstrate that serum lactate crosses the epithelial barrier into the lumen of the gut. We also show that intrarectal instillation of propionate is sufficient to reproduce the increased treadmill runtime performance observed with V. atypica gavage. Taken together, these studies reveal that V. atypica improves runtime via its metabolic conversion of exercise-induced lactate into propionate, thereby identifying a natural, microbiome-encoded enzymatic process that enhances athletic performance. Disclosure A. Kostic: Stock/Shareholder; Self; DeepBiome Therapeutics, Inc., FitBiomics, Inc. Funding American Diabetes Association/Pathway to Stop Diabetes (1-17-INI-13)