Gut Metabolites Research Articles

Banxia-Yiyiren alleviates insomnia and anxiety by regulating the gut microbiota and metabolites of PCPA-induced insomnia model rats

Banxia-Yiyiren alleviates insomnia and anxiety by regulating the gut microbiota and metabolites of PCPA-induced insomnia model rats

Synbiotic Effects of Lacticaseibacillus paracasei K56 and Prebiotics on the Intestinal Microecology of Children with Obesity.

Lacticaseibacillus paracasei K56 (L. paracasei K56) is a probiotic with weight-loss effects. However, symbiosis research on the combined effects of Lacticaseibacillus paracasei K56 and prebiotics is lacking. Therefore, the aim of this study was to investigate the effects of L. paracasei K56, xylooligosaccharide (XOS), galactooligosaccharide (GOS), polyglucose (PG), and their synbiotic combinations (XOS + K56, GOS + K56, and PG + K56) on metabolism and gut composition in children with obesity, using an in vitro fermentation model. Fecal samples were collected from 14 children with obesity for in vitro fermentation, and the effects of the various treatments in gas production and short chain fatty acid synthesis (SCFAs) were assessed. Treatment with probiotics, prebiotics, and synbiotics regulated gut microbiota and metabolites in children with obesity. GOS and XOS had higher degradation rates than PG + K56 synbiotics in the gut microbiota of children with obesity. Moreover, treatment with XOS, GOS, and their synbiotic combinations, (XOS + K56) and (GOS + K56), significantly reduced the production of gas, propionic acid, and butyric acid compared with PG + K56 treatment. Treatments with GOS + K56 and XOS + K56 altered the composition of the gut microbiota, improved the abundance of Bifidobacteria and Lactobacilli, and reduced the abundance of Escherichia/Shigella. Overall, this study provides a theoretical foundation for the use of K56-based synbiotics.

Models incorporating physical, laboratory and gut metabolite markers can be used to predict severe hepatic steatosis in MAFLD patients.

Metabolic-associated fatty liver disease (MAFLD) induced-severe hepatic steatosis poses significant health risks. Early prediction of this condition is crucial for prompt intervention. Short-chain fatty acids (SCFAs) and tryptophan are gut metabolites correlated with MAFLD pathogenesis in the gut-liver axis. This study aims to construct prediction models for severe hepatic steatosis by including SCFAs and tryptophan metabolites. This study enrolled 83 participants from the outpatient department in 2023. Physical measurements, serum metabolic and inflammatory markers, metabolites of serum SCFAs and tryptophan were collected. Severe hepatic steatosis was diagnosed using vibration-controlled transient elastography and abdominal sonography. All 40 (48.2%) participants diagnosed with severe hepatic steatosis had MAFLD, while approximately three-quarters of those without severe hepatic steatosis had MAFLD. In comparison to the non-severe hepatic steatosis group, individuals with severe hepatic steatosis exhibited higher levels of waist and arm circumference, serum triglyceride (TG), and lower levels of serum high-density lipoprotein cholesterol (HDL-C) and AST/ALT ratio. They also had higher serum levels of lipopolysaccharide-binding protein, isovaleric acid, and propionic acid, and lower levels of 3-methylvaleric acid, indole-3-propionic acid, and indoxyl sulfate. Models incorporating these markers predicted severe hepatic steatosis. One model additionally included waist circumference and triglyceride-glucose index, while the other incorporated arm circumference and TG/HDL-C ratio. The area under the curve reached 0.958 and 0.938, respectively (p < 0.001). SCFAs and tryptophan metabolites are valuable in predicting severe hepatic steatosis. Further research is needed to investigate the roles of these metabolites in MAFLD.

Metabolomics reveals changes in levels of fecal branched chain amino acids and organic acids in very preterm infants fed human milk fortified with bovine colostrum

Background & aimsHuman milk is the optimal diet for very preterm infants (VPIs), but it requires nutrient fortification to support growth. Bovine colostrum (BC), rich in intact proteins and bioactive components, could serve as a novel fortifier with potential benefits to VPIs gut health. To evaluate a possible effect of feeding BC on intestinal metabolism, the gut microbiota, and their interaction, we studied the fecal metabolome of VPIs in the first month of life, as compared with a conventional fortifier (CF, based on infant formula ingredients). MethodsFecal samples were collected from VPIs recruited to the FortiColos trial (NCT03537365, BC, n = 107; CF, n = 112) before (FT0) and one (FT1) or two (FT2) weeks after start of fortification and analyzed using 1H NMR spectroscopy. Abundances of metabolites were compared between BC versus CF groups. Further, temporal changes in metabolite levels after start of fortification, as well as correlations with specific gut bacterial genera were explored. ResultsInfants in the BC group had higher levels of fecal acetoacetate, choline, methanol, uracil, creatine, creatinine, lysine and a lower leucine at both FT1 and FT2, relative to the CF group. Asparagine, tryptophan and phenylalanine levels were higher, and butyrate was lower in the BC group at FT1. At FT2, higher fecal succinate and lower isoleucine were found in the BC group. In addition, eight metabolites (asparagine, phenylalanine, tryptophan, lysine, creatinine, acetoacetate, methanol and uracil) had fortification-specific changes over time. Correlations were found between succinate and unclassified Enterobacteriaceae, butyrate and Clostridium, uracil and Staphylococcus, as well as unclassified Enterobacteriaceae members. ConclusionOur study shows distinct fecal metabolome profiles in VPIs in the first weeks after fortification with BC versus CF. The fortification- and time-specific gut metabolite changes suggest that fortifiers influence luminal nutrient metabolism and microbiota activity in VPIs. Fortifier type for human milk affected gut health of VIPs via altered gut metabolite levels, interacting with microbiota in VPIs.

Metabolomic insights into the beneficial effects of dietary purple potato on DSS-induced murine colon colitis

Inflammatory bowel disease (IBD) is characterized by disturbance in intestinal flora and metabolomic profiles. Building on previous findings that purple potato (PP) supplementation suppresses inflammation and restores intestinal barrier in dextran sulfate sodium (DSS)-treated mice, this study examined changes in the fecal metabolome in the same cohort. Mice were fed 0 % or 10 % PP for 7 weeks, with DSS administered in the fifth week of dietary treatment followed by one-week normal drinking water recovery. A total of 68 metabolites, including amino acids, fatty acids, organic acids, carbohydrates, and polyamines, were significantly altered across the groups. PP supplementation reversed changes in 13 of the 25 DSS-altered metabolites. Six microbial metabolites derived from PP polyphenols were identified and positively correlated with M2 macrophage polarization. Data suggest that dietary PP is effective in reducing inflammation and improves gut metabolites in DSS-induced colitis mice, offering a potential dietary therapy for managing IBD.

Intestinal microflora and metabolites affect the progression of acute pancreatitis (AP)

Specific intestinal metabolites are closely associated with the classification, severity, and necrosis of acute pancreatitis (AP) and provide novel insights for in-depth clinical investigations. In this study, the gut microbiota and metabolites of 49 AP patients at different treatment stages and severities were analysed via 16S rDNA sequencing and untargeted metabolomics to investigate the trends in gut microbiota composition and metabolome profiles observed in patients with severe AP. These findings revealed an imbalance in intestinal flora homeostasis among AP patients characterized by a decrease in probiotics and an increase in opportunistic pathogens, which leads to damage to the intestinal mucosal barrier through reduced short-chain fatty acid (SCFA) secretion and disruption of the intestinal epithelium. This dysbiosis influences energy metabolism, anti-inflammatory responses, and immune regulation, and these results highlight significant differences in energy metabolism pathways. These findings suggest that the differential composition of intestinal flora, along with alterations in intestinal metabolites and metabolic pathways, contribute to the compromised integrity of the intestinal mucosal barrier and disturbances in energy metabolism in patients with severe AP.

Interaction of 4-ethyl phenyl sulfate with bovine serum albumin: Experimental and molecular docking studies.

4-ethyl phenyl sulfate (EPS), a protein-bound uremic toxin found in serum of patients suffering from autism spectrum disorders (ASD) and chronic kidney disease (CKD). As per recent advances in the field, gut metabolites after their formation goes to blood stream crosses blood brain barrier and causes neuro related problems. Increased levels of 4-EPS in human body causes anxiety in patients and its role remains elusive. 4-EPS interacts with serum albumin in human body and thus, a model study of interaction of BSA with 4-EPS is presented in support of it. Absorption spectroscopy result demonstrated decrease in bovine serum albumin (BSA) absorption upon interaction with increasing concentration of EPS in a range from 2 μM to 100 μM. Moreover, this interaction was confirmed by the fluorescence quenching in presence of metabolite. The change in secondary structure was demonstrated by circular dichroism, synchronous fluorescence and Fourier transform infra-red spectroscopy. Docking studies reveals binding score of -5.28 Kcal mol-1, demarking that 4-EPS is involved in interaction with BSA via amino acid residues, forming the stable complex. This interaction study may be helpful in devising strategies for the treatment of chronic kidney disease and other neuro related diseases, by producing synthetic compound that competes with albumin binding sites to allow 4-EPS clearance from the body.

Aspirin inhibits atherosclerosis through macrophage pyroptosis by interacting with Lactobacillus johnsonii and its metabolite butyrate

Abstract Introduction Atherosclerotic cardiovascular disease (ASCVD) is a chronic progressive disease closely related to metabolism and inflammation. Aspirin inhibits cyclooxygenase (COX) and has antiplatelet aggregation effects, considered as the cornerstone of ASCVD treatment. Numerous studies have shown that gut microbiota (GM) and its metabolites affects host metabolism. Studies have also shown that people taking aspirin exhibit specific changes in the microbiota profile. However, whether the interaction of aspirin with GM and its metabolites affects the therapeutic efficacy of aspirin in treating atherosclerosis (AS) have not been reported. Purpose This study aimed to explore the interaction of aspirin with the GM and its metabolites in the treatment of AS, to reveal the specific mechanism of the GM-metabolite axis and provide potential new targets for the combined treatment of AS. Methods To establish the mouse model of atherosclerosis by high-fat diet, and the atherosclerotic plaque burden and composition were analyzed. The role of GM in aspirin anti-atherosclerosis was explored by antibiotics and fecal microbiota transplantation (FMT). The third generation 16S RNA sequencing was used to explore the effects of aspirin on species diversity and abundance of GM, and to screen differential microorganisms for intervention of AS mice. UHPLC-MS and GC-MS were used to explore the changes of intestinal metabolites induced by aspirin. The correlation between gut microbiota and metabolites was also investigated. Finally, in vitro and in vivo experiments were performed to confirm the effects and mechanisms of metabolites on macrophage pyroptosis and atherosclerosis. Results Aspirin has anti-atherosclerosis effect. After removing gut microbiota, the therapeutic effect of aspirin on atherosclerosis was decreased. Three generations of 16S rRNA gene sequencing results showed that aspirin supplementation alters the diversity of gut microbiota, and increased the relative abundance of Lactobacillus johnsonii(L.johnsonii) and Ligilactobacillus murinus(L.murinus). After gavage of L.johnsonii and L.murinus, the plaque burden and macrophage pyroptosis were significantly reduced in AS mice. Colonization with L.johnsonii and L.murinus significantly increased the abundance of probiotics and butyrate level in the feces of AS mice and L.johnsonii and L.murinus were positively correlated with butyrate. Supplementation of butyrate inhibited macrophage pyroptosis and atherosclerosis in vivo. In vitro, butyrate could inhibit the expression of NLRP3/Caspase-1/IL-1β and pyroptosome production, and this process mainly by activating butyrate receptors GPR41, GPR43 and GPR109A. Conclusions The gut microbiota may mediate the anti-AS effect of aspirin by promoting an increase in the abundance of L.johnsonii and L.murinus. Butyrate produced by Lactobacillus may mediate the anti-AS effect of aspirin, and inhibiting macrophage pyroptosis and the progression of AS.

The associations between gut microbiota and fecal metabolites with intelligence quotient in preschoolers

BackgroundThe awareness of the association between the gut microbiota and human intelligence levels is increasing, but the findings are inconsistent. Furthermore, few research have explored the potential role of gut microbial metabolites in this association. This study aimed to investigate the associations of the gut microbiota and fecal metabolome with intelligence quotient (IQ) in preschoolers.MethodsThe 16 S rRNA sequencing and widely targeted metabolomics were applied to analyze the gut microbiota and fecal metabolites of 150 children aged 3–6 years. The Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) was used to assess the cognitive competence.ResultsThe observed species index, gut microbiome health index, and microbial dysbiosis index presented significant differences between children with full-scale IQ (FSIQ) below the borderline (G1) and those with average or above-average (all P < 0.05). The abundance of Acinetobacter, Blautia, Faecalibacterium, Prevotella_9, Subdoligranulum, Collinsella, Dialister, Holdemanella, and Methanobrevibacter was significantly associated with preschooler’s WPPSI-IV scores (P < 0.05). In all, 87 differential metabolites were identified, mainly including amino acid and its metabolites, fatty acyl, and benzene and substituted derivatives. The differential fecal metabolites carnitine C20:1-OH, 4-hydroxydebrisoquine, pantothenol, creatine, N,N-bis(2-hydroxyethyl) dodecanamide, FFA(20:5), zerumbone, (R)-(-)-2-phenylpropionic acid, M-toluene acetic acid, trans-cinnamaldehyde, isonicotinic acid, val-arg, traumatin, and 3-methyl-4-hydroxybenzaldehyde were significantly associated with the preschooler’s WPPSI-IV scores (P < 0.05). The combination of Acinetobacter, Isonicotinic acid, and 3-methyl-4-hydroxybenzaldehydenine may demonstrate increased discriminatory power for preschoolers in G1.ConclusionThis study reveals a potential association between gut microbiome and metabolites with IQ in preschoolers, providing new directions for future research and practical applications. However, due to limitations such as the small sample size, unclear causality, and the complexity of metabolites, more validation studies are still needed to further elucidate the mechanisms and stability of these associations.

Expression of PGC-1α, PPAR-α and UCP1 genes, metabolic and anthropometric factors in response to sodium butyrate supplementation in patients with obesity: a triple-blind, randomized placebo-controlled clinical trial.

There is increasing evidence that gut metabolites have a role in the etiology of obesity. This study aimed to investigate the effects of sodium butyrate (NaB) supplementation on the expression of peroxisome proliferator-activated receptor (PPAR) gamma coactivator-1α (PGC-1α), PPAR-α, and uncoupling protein-1 (UCP-1) genes, as well as on the metabolic parameters and anthropometric indices in persons with obesity. In this triple-blind placebo-controlled randomized clinical trial, 50 individuals with obesity were randomly assigned to NaB (600 mg/day) + hypo-caloric diet or placebo group + hypo-caloric diet for 8 weeks. The study measured the participants' anthropometric characteristics, food consumption, and feelings of hunger in addition to the serum levels of metabolic indices and the mRNA expression of the PGC-1α, PPAR-α, and UCP-1 genes in peripheral blood mononuclear cells (PBMCs). PGC-1α and UCP-1 genes expression significantly increased in NaB group compared to the placebo at the endpoint. A significant decrease in weight, BMI, and waist circumference (WC) was observed in NaB group. Among the metabolic factors, NaB significantly decreased fasting blood sugar (FBS) (P = 0.04), low-density lipoprotein cholesterol (LDL-C) (P = 0.038) and increased high-density lipoprotein cholesterol (HDL-C) (P = 0.016). NaB could not significantly change serum GLP-1 level. This study unveiled NaB supplementation alone cannot have significant beneficial effects on anthropometric, and biochemical factors. NaB could affect anthropometric and metabolic risk variables associated with obesity only when prescribed, along with calorie restriction. This study was registered in the Iranian Registry of Clinical Trials ( https://en.irct.ir/trial/53968 ) on 31 January 2021 (registry number IRCT20190303042905N2).

Study on the Differences in Fecal Metabolites and Microbial Diversity of Jiangshan Black-Bone Chickens with Different Earlobe Colors

The differences in earlobe color of Jiangshan black-bone chickens have been reported to be caused by the combined effects of melanin and collagen. In this study, we conducted LC-MS untargeted metabolomics and 16S rDNA diversity sequencing on the cecal contents of two types of earlobes: peacock green (Blue and Green group) and dark reddish-purple (Black group). The metabolomic sequencing identified a total of 747 differential metabolites (DMs), in which the metabolites were primarily enriched in tyrosine and tryptophan metabolism pathways between peacock green and dark reddish-purple earlobes. There were 15 different bacterial taxa among the three groups of earlobes at the genus level, and correlation analysis between metabolites and microbes revealed that the DMs between peacock green and dark reddish-purple earlobes were positively correlated with the different bacterial taxa. In short, there are differences in gut microbiota and metabolites between Jiangshan black-bone chickens with peacock green earlobes and those with dark reddish-purple earlobes. Our results suggest that the bacterial phyla Firmicutes and Bacteroidota may influence melanin synthesis by affecting tryptophan metabolism, induced by 5-Methoxyindoleacetate, and tyrosine metabolism, induced by maleylacetoacetic acid and maleic acid, leading to differences in earlobe color.

The role of gut microbiome and its metabolites in pancreatitis.

Gut microbiome plays a vital role in the intestinal ecosystem and has close association with metabolites. Due to the development of metabolomics and microbiomics, recent studies have observed that alteration of either the gut microbiome or metabolites may have effects on the progression of pancreatitis. Several new treatments based on the gut microbiome or metabolites have been studied extensively in recent years. Gut microbes, such as Bifidobacterium, Akkermansia, and Lactobacillus, and metabolites, such as short-chain fatty acids, bile acids, vitamin, hydrogen sulfide, and alcohol, have different effects on pancreatitis. Some preliminary studies about new intervention measures were based on the gut microbiome and metabolites such as diet, prebiotic, herbal medicine, and fecal microbiota transplantation. This review aims to summarize the recent advances about the gut microbiome, metabolites, and pancreatitis in order to determine the potential beneficial role of the gut microbiome and metabolites in pancreatitis.

Synergistic amelioration of obesity in high‐fat diet–fed mice by Bifidobacterium longum and green banana powder through targeting multiple pathways

AbstractLong‐term consumption of high‐fat diet (HFD) is a major significant risk factor for various diseases, including hyperlipidemia, diabetes, cardiovascular disease, and certain cancers. Recently, there has been a focus on effective dietary methods to improve lipid absorption and accumulation in the body. Simultaneously, exploring non‐pharmacological interventions to counteract the adverse consequences of obesity is crucial. Probiotics and prebiotics emerge as promising alternatives in this context, with their combined utilization yielding substantial effects surpassing those achieved by individual application alone. The aim of this study was to investigate the combined effects of Bifidobacterium longum (BL) SYP‐B4138 and green banana powder (GBP) on HFD‐induced obesity while exploring their underlying mechanisms. The findings demonstrated that the combined intervention exhibited significantly greater efficacy than BL or GBP alone, including in mitigating weight gain and organ weight among obese mice, while also improving lipid profile, glucose tolerance, and inflammation levels. Furthermore, it effectively reduced liver fat accumulation. The mechanism study revealed that the combined intervention increased the expression of gene‐related lipid metabolism, such as Pparα, Cpt1a, Fxr, Cyp7a1, and Bsep, while decreasing expression of the regulatory genes involved in fat synthesis, Acc1, Srebpf1, and Pparγ. The correlation analysis of gut microbes and metabolites suggests that the combined effect of BL and GBP can reverse the intestinal microecological imbalance, leading to changes in bile acids, glycerophospholipids, and other related metabolites. Overall, this study demonstrates that BL combined with GBP can effectively alleviate dietary obesity, highlighting its potential as a non‐pharmacological intervention for weight reduction.

The Impact of Fermented Milk Products Containing Bifidobacterium longum BB536 on the Gut Environment: A Randomized Double-Blind Placebo-Controlled Trial

Probiotics, particularly those native to the gut microbiota, have a profound influence on the gut environment. In this study, we conducted a randomized placebo-controlled, double-blind, parallel-group comparison trial to investigate the effects of Bifidobacterium longum BB536 (B. longum BB536) on the fecal microbiota and metabolite compositions in healthy individuals. We compared the effects of fermented milk produced solely with Streptococcus thermophiles and Lactobacillus bulgaricus (placebo group) and fermented milk supplemented with B. longum BB536 (BY group). Our findings revealed a significantly greater relative abundance of Faecalibacterium in the BY group than in the placebo group by the 3rd day, a trend that persisted until the end of the trial on the 17th day. Additionally, the BY group presented significantly increased concentrations of tryptophan (Trp), Indole-3-lactic acid, and Indole-3-aldehyde on the 17th day. A significant positive correlation was observed between the relative abundance of Faecalibacterium and the number of viable B. longum BB536 bacteria in the feces. The concentrations of Trp and Indole-3-acetic acid were also significantly correlated with the number of viable B. longum BB536 bacteria in the feces. Our results suggest that B. longum BB536 intake can modulate the gut microbiota and metabolite profiles, which are general indicators for monitoring the gut environment, potentially conferring health benefits to the host.

Identification of metabolites from the gut microbiota in hypertension via network pharmacology and molecular docking

Hypertension is the most prevalent cardiovascular disease, affecting one-third of adults. All antihypertensive drugs have potential side effects. Gut metabolites influence hypertension. The objective of this study was to identify antihypertensive gut metabolites through network pharmacology and molecular docking techniques and to validate their antihypertensive mechanisms via in vitro experiments. A total of 10 core antihypertensive targets and 18 gut metabolites that act on hypertension were identified. Four groups of protein metabolites, namely, CXCL8-baicalein, CXCL8-baicalin, CYP1A1-urolithin A, and PTGS2-equol, which have binding energies of − 7.7, − 8.5, − 7.2, and − 8.8 kcal-mol−1, respectively, were found to have relatively high affinities. Based on its drug-likeness properties in silico and toxicological properties, equol was identified as a potential antihypertensive metabolite. On the basis of the results of network pharmacology and molecular docking, equol may exert antihypertensive effects by regulating the IL-17 signaling pathway and PTGS2. A phenylephrine-induced H9c2 cell model was subsequently utilized to verify that equol inhibits cell hypertrophy (P < 0.05) by inhibiting the IL-17 signaling pathway and PTGS2 (P < 0.05). This study demonstrated that equol has the potential to be developed as a novel therapeutic agent for the treatment of hypertension.Graphical

Isomalto-Oligosaccharide Potentiates Alleviating Effects of Intermittent Fasting on Obesity-Related Cognitive Impairment during Weight Loss and the Rebound Weight Gain.

Obesity-related cognitive dysfunction poses a significant threat to public health. The present study demonstrated mitigating effects of intermittent fasting (IF) and its combination with isomalto-oligosaccharides and IF (IF + IMO) on cognitive impairments induced by a high-fat-high-fructose (HFHF) diet in mice, with IF + IMO exhibiting superior effects. Transcriptomic analysis of the hippocampus revealed that the protective effects on cognition might be attributed to the suppression of toll-like receptor 4 (TLR4)/NFκB signaling, oxidative phosphorylation, and neuroinflammation. Moreover, both IF and IF + IMO modulated the gut microbiome and promoted the production of short-chain fatty acids, with IF + IMO displaying more pronounced effects. IF + IMO-modulated gut microbiota, metabolites, and molecular targets associated with cognitive impairments were further corroborated using human data from public databases Gmrepo and gutMgene. Furthermore, the fecal microbiome transplantation confirmed the direct impacts of IF + IMO-derived microbiota on improving cognition functions by suppressing TLR4/NFκB signaling and increasing BDNF levels. Notably, prior exposure to IF + IMO prevented weight-regain-induced cognitive decline, suppressed TLR4/NFκB signaling and inflammatory cytokines in the hippocampus, and mitigated weight regain-caused gut dysbacteriosis without altering body weight. Our study underscores that IMO-augmented alleviating effects of IF on obesity-related cognitive impairment particularly during weight-loss and weight-regain periods, presenting a novel nutritional strategy to tackle obesity-related neurodegenerative disorders.

Association of gut microbiota and gut metabolites and adverse outcomes in biliary atresia: A longitudinal prospective study

Association of gut microbiota and gut metabolites and adverse outcomes in biliary atresia: A longitudinal prospective study

P1.03E.01 Effect of Gut Microbiota and Metabolites on the Efficacy of Immunotherapy Combined with Chemotherapy in Lung Squamous Cell Carcinoma Patients

P1.03E.01 Effect of Gut Microbiota and Metabolites on the Efficacy of Immunotherapy Combined with Chemotherapy in Lung Squamous Cell Carcinoma Patients

Reply to: "Unveiling the distinctive gut microbiota and metabolites in liver cirrhosis and its complications: Novel diagnostic biomarkers".

Reply to: "Unveiling the distinctive gut microbiota and metabolites in liver cirrhosis and its complications: Novel diagnostic biomarkers".

GC-MS quantification of fecal short-chain fatty acids and spectrophotometric detection of indole: Do rectal swabs produce comparable results as stool samples? - A pilot study.

The exploration of the gut microbiome and related metabolites holds an exciting future in health science. The challenges associated with fecal sample testing are proper sample collection, sterile transportation, optimal transport conditions, and processing as all these factors could potentially change the microbiome composition, further exacerbated by the patient's customary discomfort regarding feces samples. The study aimed to compare the usage of rectal swabs and stool samples for short-chain fatty acid estimation using gas chromatography-mass spectrometry (GC-MS) and indole estimation using spectrophotometry. From May 2022 to June 2022, three women were recruited from the Department of Obstetrics and Gynecology (OBG) in a secondary care hospital in coastal Karnataka. During their clinical visit, a rectal swab was collected, and the stool sample was transported to the hospital from the patient's home in sterile containers provided. After the extraction, short-chain fatty acids (acetate, propionate, and butyrate) were quantified using GC-MS. The fecal indole concentration was determined using a hydroxylamine-based assay. The GC-MS analysis failed to detect the concentrations of short-chain fatty acids in rectal swab samples. Indole concentrations in stool and swab samples were significantly different. The study's findings do not support the use of rectal swabs to analyze gut metabolites.