Stool Short Chain Fatty Acid Research Articles

Gut microbial changes associated with obesity in youth with type 1 diabetes: a Pilot Study.

Obesity is prevalent in type 1 diabetes (T1D) and is problematic with higher risk for diabetes complications. It is unknown to what extent gut microbiome changes are associated with obesity and T1D. To describe the gut microbiome and microbial metabolite changes associated with obesity in T1D. We hypothesized significant gut microbial and metabolite differences in lean T1D youth (BMI: 5-<85%) vs. those with obesity (BMI: ≥95%). We analyzed stool samples for gut microbial (using metagenomic shotgun sequencing) and short-chain fatty acid (SCFA) differences in lean (n=27) and obese (n=21) T1D youth in a pilot study. The mean±SD age was 15.3±2.2yrs, A1c 7.8±1.3%, diabetes duration 5.1±4.4yrs, 42.0% females, and 94.0% were White. Bacterial community composition showed between sample diversity differences (β-diversity) by BMI group (p=0.013). There was a higher ratio of Prevotella to Bacteroides in the obese group (p=0.0058). There was a differential distribution of significantly abundant taxa in either the lean or obese groups, including increased relative abundance of Prevotella copri, among other taxa in the obese group. Functional profiling showed an upregulation of branched chain amino acid (BCAA) biosynthesis in the obese group and upregulation of BCAA degradation, tyrosine metabolism and secondary bile acid biosynthesis in the lean group. Stool SCFAs were higher in the obese versus the lean group (p<0.05 for all). Our findings identify a gut microbiome and microbial metabolite signature associated with obesity in T1D. These findings could help identify gut microbiome targeted therapies to manage obesity in T1D.

Assessment of short-chain fatty acid (SCFA) and circulating cytokine trends in a clinical trial of nivolumab/ipilimumab and CBM588 in metastatic renal cell carcinoma (mRCC).

4556 Background: Recent evidence suggests that blood and stool SCFA levels (including acetic acid and butyric acid) are associated with clinical outcomes with immune checkpoint blockade in melanoma (Nomura et al. JAMA Network Open 2020). Herein, we report trends in plasma SCFA and cytokine levels in a randomized phase I clinical trial of CBM588, a live bacterial product containing a butyric acid-producing bacterium, C. butyricum, in patients with mRCC treated with immune checkpoint blockade. Methods: Treatment naïve patients with clear cell and/or sarcomatoid mRCC and intermediate- or high-risk IMDC disease were randomized to nivolumab/ipilimumab or nivolumab/ipilimumab and CBM588 in a 1:2 fashion. Blood samples were collected at baseline and on treatment (week 12 +/- 5 weeks). Quantitative assessment of plasma SCFAs and cytokines was performed by liquid chromatography-mass spectrometry and a Human Cytokine 30-plex protein assay, respectively. Changes in SCFAs and cytokine levels were assessed using paired sample T-tests. Results: A total of 29 patients were randomized to the nivolumab/ipilimumab (n=19) and nivolumab/ipilimumab with CBM588 (n=10) arms. Objective response rates (ORR) with nivolumab/ipilimumab with and without CBM588 were 58% and 20%, respectively. No statistically significant change in SCFA levels was observed between baseline and on-treatment samples in either arm. Notably, however, a numerical increase in levels of acetic acid (414.3 vs 814.0 nmol/g) and isobutyric acid (7.9 vs 9.0 nmol/g) was seen in the nivolumab/ipilimumab and CBM588 arm. In contrast, both factors decreased in the nivolumab/ipilimumab arm (563.1 vs 401.1 nmol/g and 10.0 vs 8.8 nmol/g, respectively). In patients with an uptrend in isobutyric acid levels with nivolumab/ipilimumab and CBM588, ORR was 64% compared to 50% in those without an uptrend in such levels). Similarly, patients with increases in butyric acid with nivolumab/ipilimumab and CBM588 had an ORR of 66%, compared to 43% among those without an increase in butyric acid levels. Correlations between acetic acid and chemokines, including CCL2 and CCL4, were observed with correlation coefficients of 0.83 and 0.82, respectively (p&lt;0.001 for both). Conclusions: A substantial increase in isobutyrate levels in CBM588 responders is indicative of altered amino acid metabolism (specifically, valine and leucine) by modified gut flora in these patients. These observations, combined with alterations in serum cytokines, provide biologic rationale for the clinical activity seen with CBM588 in combination with nivolumab/ipilimumab in this trial. Clinical trial information: NCT03829111 .

Gestational diabetes Is uniquely associated with altered early seeding of the infant gut microbiota

Gestational diabetes mellitus (GDM) is a worldwide public health problem affecting up to 27% of pregnancies with high predictive values for childhood obesity and inflammatory diseases. Compromised seeding of the infant gut microbiota is a risk factor for immunologic and metabolic diseases in the offspring; however, how GDM along with maternal obesity interact to alter colonization remains unknown. We hypothesized that GDM individually and in combination with maternal overweight/obesity would alter gut microbial composition, diversity, and short-chain fatty acid (SCFA) levels in neonates. We investigated 46 full-term neonates born to normal-weight or overweight/obese mothers with and without GDM, accounting for confounders including cesarean delivery, lack of breastfeeding, and exposure to antibiotics. Gut microbiota in 2-week-old neonates born to mothers with GDM exhibited differences in abundance of 26 microbial taxa; 14 of which showed persistent differential abundance after adjusting for pre-pregnancy BMI. Key pioneering gut taxa, including potentially important taxa for establishing neonatal immunity, were reduced. Lactobacillus, Flavonifractor, Erysipelotrichaceae, and unspecified families in Gammaproteobacteria were significantly reduced in neonates from mothers with GDM. GDM was associated with an increase in microbes involved in suppressing early immune cell function (Phascolarctobacterium). No differences in infant stool SCFA levels by maternal phenotype were noted; however, significant correlations were found between microbial abundances and SCFA levels in neonates. Our results suggest that GDM alone and together with maternal overweight/obesity uniquely influences seeding of specific infant microbiota in patterns that set the stage for future risk of inflammatory and metabolic disease.

A Unique Gut Microbiome-Physical Function Axis Exists in Older People with HIV: An Exploratory Study.

Impairments in physical function and increased systemic levels of inflammation have been observed in middle-aged and older persons with HIV (PWH). We previously demonstrated that in older persons, associations between gut microbiota and inflammation differed by HIV serostatus. To determine whether relationships between the gut microbiome and physical function measurements would also be distinct between older persons with and without HIV, we reanalyzed existing gut microbiome and short chain fatty acid (SCFA) data in conjunction with previously collected measurements of physical function and body composition from the same cohorts of older (51-74 years), nonfrail PWH receiving effective antiretroviral therapy (N = 14) and age-balanced uninfected controls (N = 22). Associations between relative abundance (RA) of the most abundant bacterial taxa or stool SCFA levels with physical function and body composition were tested using HIV-adjusted linear regression models. In older PWH, but not in controls, greater RA of Alistipes, Escherichia, Prevotella, Megasphaera, and Subdoligranulum were associated with reduced lower extremity muscle function, decreased lean mass, or lower Short Physical Performance Battery (SPPB) scores. Conversely, greater RA of Dorea, Coprococcus, and Phascolarctobacterium in older PWH were associated with better muscle function, lean mass, and SPPB scores. Higher levels of the SCFA butyrate associated with increased grip strength in both PWH and controls. Our findings indicate that in older PWH, both negative and positive associations exist between stool microbiota abundance and physical function. Different relationships were observed in older uninfected persons, suggesting features of a unique gut-physical function axis in PWH.

57437 Effects of Prebiotics on the Gut Microbiome Profile, Beta-cell Function and Immune Markers in Newly-Diagnosed Type 1 Diabetes

ABSTRACT IMPACT: The proposed research study will provide critical pilot data on the effect of using the prebiotic (HAMS-AB) on the gut microbiome profile, Beta-cell function and immune markers in humans with T1D. OBJECTIVES/GOALS: The overall objective of this study is to assess how the prebiotic high amylose maize starch that has been acetylated and butyrylated (HAMS-AB) impacts the gut microbiome profile, short chain fatty acid (SCFA) production, glycemia, Beta-cell function/health and immune responses in newly diagnosed youth with type 1 diabetes (T1D). METHODS/STUDY POPULATION: We are performing a pilot randomized cross-over trial. We plan to recruit 12 newly-diagnosed T1D youth with residual Beta-cell function between 12-16 years of age. We will profile the gut microbiome using metagenomics, measure stool SCFA levels using mass spectrometry, assess glycemia using continuous glucose monitoring, assess insulin production using mixed meal tolerance testing, assess Beta-cell stress using proinsulin/C-peptide levels, and test immune responses by examining cytokine levels and frequency, phenotype and function of T cell markers in peripheral blood. RESULTS/ANTICIPATED RESULTS: Thus far, we have enrolled 3 participants, 1 has completed the study. Baseline assessments indicate that we have technical feasibility of performing the above studies and measurements. Recruitment and enrollment are ongoing. We hypothesize that the use of HAMS-AB in newly diagnosed youth with T1D will (i) improve the gut microbiome profile, (ii) increase SCFA production, (iii) improve overall glycemia and Beta-cell function and (iv) modulate the immune system and mitigate autoimmunity. DISCUSSION/SIGNIFICANCE OF FINDINGS: Given the failure to develop a cure for T1D despite multiple completed intervention studies and the unknown long-term effects of immune-modulatory therapy on those at risk for or those diagnosed with T1D, prebiotics such as HAMS-AB may offer a simple, safe, yet inexpensive and tolerated dietary alternative approach to mitigating disease.

Gestational Diabetes Is Uniquely Associated With Altered Early Seeding of the Infant Gut Microbiota.

Gestational diabetes mellitus (GDM) is a worldwide public health problem affecting up to 27% of pregnancies with high predictive values for childhood obesity and inflammatory diseases. Compromised seeding of the infant gut microbiota is a risk factor for immunologic and metabolic diseases in the offspring; however, how GDM along with maternal obesity interact to alter colonization remains unknown. We hypothesized that GDM individually and in combination with maternal overweight/obesity would alter gut microbial composition, diversity, and short-chain fatty acid (SCFA) levels in neonates. We investigated 46 full-term neonates born to normal-weight or overweight/obese mothers with and without GDM, accounting for confounders including cesarean delivery, lack of breastfeeding, and exposure to antibiotics. Gut microbiota in 2-week-old neonates born to mothers with GDM exhibited differences in abundance of 26 microbial taxa; 14 of which showed persistent differential abundance after adjusting for pre-pregnancy BMI. Key pioneering gut taxa, including potentially important taxa for establishing neonatal immunity, were reduced. Lactobacillus, Flavonifractor, Erysipelotrichaceae, and unspecified families in Gammaproteobacteria were significantly reduced in neonates from mothers with GDM. GDM was associated with an increase in microbes involved in suppressing early immune cell function (Phascolarctobacterium). No differences in infant stool SCFA levels by maternal phenotype were noted; however, significant correlations were found between microbial abundances and SCFA levels in neonates. Our results suggest that GDM alone and together with maternal overweight/obesity uniquely influences seeding of specific infant microbiota in patterns that set the stage for future risk of inflammatory and metabolic disease.

P0920THE METHIONINE RESTRICTION DIET ATTENUATES CHRONIC KIDNEY PROGRESSION IN MICE

Abstract Background and Aims The clinical usefulness of protein-restricted diets is known to slow the progression of obesity, fatty liver, aging and cancer. Protein-restricted diet in chronic kidney disease is known to alleviate the deterioration of the renal function. The purpose of this study is to confirm whether the reduction in new function can be improved when methionine restricted (MR) diet is supplied in the chronic kidney disease (CKD) animal model and to study the its renoprotection mechanism. Method We used four-week-old C57L/B6 to make a CKD model by administration 0.025% adenine chow mixed with R3 diet for four weeks for the control group. For the MR diet group, we supplied the mixture of 0.025% adenine with methionine/Choline Deficient Diet. We measured serum blood urea nitrogen (BUN), serum creatinine, gut permeability, stool short chain fatty acid (SCFA), kidney α-SMA and renal pathology. This study was approved by Korea University Institutional Animal Care and Use Committee (KOREA-2019-0047). Results The principal coordinates analysis of the microbiome showed the two groups have distinctive component features. The stool SCFA, especially butyrate was increased in the MR diet group. However, gut permeability using FITC-dextran showed no significant change. The kidney α-SMA and MT stain area showed that the MR diet could improve renal fibrosis. The kidney inflammation including neutrophil and macrophage infiltration was also improved in histology analysis. The macrophage phenotype was more favorable to M2 type. Serum BUN and creatinine were significantly attenuated in the MR diet group. Conclusion In conclusion, the MR diet has a reno-protective effect in adenine induced CKD. The MR diet increased butyrate production and decreased renal inflammation and fibrosis. These results shed light on the role of protein restriction diet for CKD management in the real world.

Impact of Fiber-Based Enteral Nutrition on the Gut Microbiome of ICU Patients Receiving Broad-Spectrum Antibiotics: A Randomized Pilot Trial.

Dietary fiber increases the abundance of bacteria that metabolize fiber into short-chain fatty acids and confers resistance against gut colonization with multidrug-resistant bacteria. This pilot trial estimated the effect of fiber on gut short-chain fatty acid-producing bacteria in the ICU. Randomized, controlled, open label trial. Medical ICU. Twenty ICU adults receiving broad-spectrum IV antibiotics for sepsis. 1:1 randomization to enteral nutrition with mixed soy- and oat-derived fiber (14.3 g fiber/L) versus calorie- and micronutrient-identical enteral nutrition with 0 g/L fiber. Rectal swabs and whole stools were collected at baseline and on study Days 3, 7, 14, and 30. The primary outcome was within-individual change in the cumulative relative abundance of short-chain fatty acid-producing taxa from baseline to Day 3 based on 16S sequencing of rectal swabs. The secondary outcome was Day 3 cumulative short-chain fatty acid levels based on mass spectrometry of whole stools. Analyses were all intent to treat. By Day 3, the fiber group received a median of 32.1 g fiber cumulatively (interquartile range, 17.6-54.6) versus 0 g fiber (interquartile range, 0-4.0) in the no fiber group. The median within-individual change in short-chain fatty acid producer relative abundance from baseline to Day 3 was +61% (interquartile range -51 to +1,688) in the fiber group versus -46% (interquartile range, -78 to +13) in the no fiber group (p = 0.28). Whole stool short-chain fatty acid levels on Day 3 were a median of 707 μg short-chain fatty acids/g stool (interquartile range, 190-7,265) in the fiber group versus 118 μg short-chain fatty acids/g stool (interquartile range, 22-1,195) in the no fiber group (p = 0.16). Enteral fiber was associated with nonsignificant trends toward increased relative abundance of short-chain fatty acid-producing bacteria and increased short-chain fatty acid levels among ICU patients receiving broad-spectrum IV antibiotics. Larger studies should be undertaken and our results can be used for effect size estimates.

Differential Effects of Lactobacillus casei Strain Shirota on Patients With Constipation Regarding Stool Consistency in China.

Background/AimsProbiotics are expected to confer benefits on patients with constipation, but how probiotics act on constipated patients with variable stool consistencies remains unclear. We investigated the effect of Lactobacillus casei strain Shirota (LcS) on constipation-related symptoms, especially stool consistency, of constipated patients.MethodsConstipated patients meeting the Rome III criteria were divided into 3 groups according to the Bristol Stool Form Scale (BSFS): hard (hard stool [HS], BSFS < 3), normal (normal stool [NS], ≤ 3 BSFS ≤ 4), and soft (soft stool [SS], 4 < BSFS ≤ 5) stools. Subjects in each group consumed a probiotic beverage containing 1010 colony-forming units of LcS daily for 28 days.ResultsLcS intervention significantly alleviated constipation-related symptoms and increased defecation frequency in all subjects. Four weeks of LcS supplementation softened the hard stools in HS, hardened the soft stools in SS, and did not alter the ideal stool consistency in NS. The short-chain fatty acid (SCFA) concentrations were highest in SS, followed by NS and HS. LcS intervention increased the stool SCFA levels in HS but reduced or did not alter the levels in NS and SS. LcS intervention increased the Pseudobutyrivibrio and Roseburia abundances in HS and decreased the Pseudobutyrivibrio abundance in SS.ConclusionsLcS supplementation improved the constipation-related symptoms in constipated subjects. Differences in baseline stool consistency could result in different anti-constipation effects of LcS intervention. LcS balanced the stool consistency—softened the HS and hardened the SS. These effects could be associated with modulation of the gut microbiota and SCFA production.

Dietary Fiber Treatment Corrects the Composition of Gut Microbiota, Promotes SCFA Production, and Suppresses Colon Carcinogenesis

Epidemiological studies propose a protective role for dietary fiber in colon cancer (CRC). One possible mechanism of fiber is its fermentation property in the gut and ability to change microbiota composition and function. Here, we investigate the role of a dietary fiber mixture in polyposis and elucidate potential mechanisms using TS4Cre × cAPCl°x468 mice. Stool microbiota profiling was performed, while functional prediction was done using PICRUSt. Stool short-chain fatty acid (SCFA) metabolites were measured. Histone acetylation and expression of SCFA butyrate receptor were assessed. We found that SCFA-producing bacteria were lower in the polyposis mice, suggesting a decline in the fermentation product of dietary fibers with polyposis. Next, a high fiber diet was given to polyposis mice, which significantly increased SCFA-producing bacteria as well as SCFA levels. This was associated with an increase in SCFA butyrate receptor and a significant decrease in polyposis. In conclusion, we found polyposis to be associated with dysbiotic microbiota characterized by a decline in SCFA-producing bacteria, which was targetable by high fiber treatment, leading to an increase in SCFA levels and amelioration of polyposis. The prebiotic activity of fiber, promoting beneficial bacteria, could be the key mechanism for the protective effects of fiber on colon carcinogenesis. SCFA-promoting fermentable fibers are a promising dietary intervention to prevent CRC.

The early life gut microbiota and atopic disease

Background Asthma is the most prevalent of all childhood diseases and accounts for the majority of hospitalizations and school absences in children [1]. Current mouse model research has identified the early life gut microbiota as a potential therapeutic target for the prevention of asthma and atopic diseases [2-4]. We hypothesize that the early life gut microbiota could play a similar preventative role against atopic disease development in humans. Methods 1262 children enrolled in the Canadian Healthy Infant Longitudinal Development (CHILD) Study with complete skin prick test and wheeze data at one year were grouped into four clinically relevant phenotypes: atopy + wheeze, atopy only, wheeze only, and control. Bacterial 16S rDNA from 3-month and 1-year stool samples of 319 children in these four phenotypes was extracted, amplified, and subjected to high throughput Illumina sequencing. Quantitative polymerase chain reaction (qPCR) and short chain fatty acid (SCFA) analysis were also conducted on 44 children in the two extreme phenotypes (atopy + wheeze vs. control). Results 16S sequence analysis of our sample cohort (319 subjects) identified bacterial populations that differed in abundance in the atopy + wheeze group at 3-months of age but not at 1-year of age. Additionally, significant changes in the abundance of certain bacterial genera were found in the atopy + wheeze group when compared to controls by qPCR at 3-months of age only. Changes in stool short chain fatty acid production between the atopy + wheeze group and the control group were also observed at 3months of age only. Conclusions Shifts in the relative abundance of certain gut bacterial populations and differences in the levels of stool SCFAs before 3-months of age are associated with atopy and wheeze at one year of age.

G205(P) Stool Short Chain Fatty Acid Concentrations in a Cohort of Preterm Very Low Birth Weight Infants with and Without Necrotising Enterocolitis

IntroductionDiagnostic markers of necrotising enterocolitis (NEC) remain evasive. Stool short chain fatty acids (sSCFAs) are a product of bacterial fermentation of undigested carbohydrate and protein noted to alter in animal...

A Randomized Placebo‐controlled Comparison of 2 Prebiotic/Probiotic Combinations in Preterm Infants: Impact on Weight Gain, Intestinal Microbiota, and Fecal Short‐chain Fatty Acids

To compare the effect of 2 prebiotic/probiotic products on weight gain, stool microbiota, and stool short-chain fatty acid (SCFA) content of premature infants. This randomized, blinded, placebo-controlled trial included 90 premature infants treated with either a dietary supplement containing 2 lactobacillus species plus fructooligosaccharides (CUL, Culturelle, ConAgra, Omaha, NE), a supplement containing several species of lactobacilli and bifidobacteria plus fructooligosaccharides (PBP, ProBioPlus DDS, UAS Laboratories, Eden Prairie, MN), or placebo (a dilute preparation of Pregestamil formula) twice daily for 28 days or until discharge if earlier. The primary outcome was weight gain. Secondary outcomes were stool bacterial analysis by culture and 16S rDNA quantitative polymerase chain reaction and stool SCFA content measured by high performance liquid chromatography. Both prebiotic/probiotic combinations contained more bacterial species than noted on the label. No significant effect on infant growth of either prebiotic/probiotic supplement was observed. By cultures, 64% of infants receiving PBP became colonized with bifidobacteria, compared with 18% of infants receiving CUL and 27% of infants receiving placebo (chi-square, P = 0.064). No differences were noted between groups in colonization rates for lactobacilli, Gram-negative enteric bacteria, or staphylococci. By 16S rDNA polymerase chain reaction analysis, the bifidobacteria content in the stools of the infants receiving PBP was higher than in the infants receiving CUL or placebo (Kruskal-Wallis, P = 0.011). No significant differences in stool SCFA content were detected between groups. No adverse reactions were noted. Infants receiving PBP were more likely to become colonized with bifidobacteria. No significant differences in weight gain or stool SCFA content were detected.

Increasing butyrate concentration in the distal colon by accelerating intestinal transit

Background—Populations at low risk of colonic cancer consume large amounts of fibre and starch and pass acid, bulky stools. One short chain fatty acid (SCFA), butyrate, is the colon’s main...