Table 2:
Summary of pathophysiologic mechanisms related to gut microbiota in patients with FGIDs (reprint from9)
| Study | Study population |
Intervention | Sample | Mechanism studied |
Role of microbiota |
|---|---|---|---|---|---|
| Shin et al, 201892 | 60 IBS-D | L gasseri BNR 17 vs pcbo | Fecal | Transit | Transit significantly ↑ during 8 wk with L gasseri BNR17 |
| Tap et al, 201720 | 110 IBS, 39 HV | NA | Fecal, mucosal | Transit, GBA | ↑Transit with Clostridiales vs Prevotella and Bacteroides enterotypes No association between HADS and enterotype |
| Acosta et al, 201693 | 24 nonconstipat ed IBS | Rifaximin vs pcbo | Fecal | Transit, permeability, SCFA and bile acid production | No significant effects of rifaximin on permeability, bile acids, SCFAs Rifaximin associated with ↑ascending colon emptying, and colonic transit at 48 h |
| Dior et al, 201694 | 15 HV, 15 IBS-C, 16 IBS-D |
NA | Fecal | Fecal bile acids | ↓Bacterial deconjugation of bile acids in IBS-D and IBS-C feces vs HV |
| Le Neve et al, 201695 | 100 IBS | NA | Fecal | Sensation, transit | Response to lactulose challenge associated with rectal sensitivity but not with fecal microbiota or transit |
| Chumpitazi et al, 201496 | 12 IBS children | LFSFD | Fecal | Transit, metabolite composition | LFSD response associated with ↑abundance of Sporobacter and Subdoligranulum and ↓ Bacteroides, but not with transit Stool metabolites (L-urobilin, cholate) associated with response and microbiome composition |
| Jeffery et al, 201297 | 37 IBS, 20 HV | NA | Fecal | Sensation, transit, GBA | Proteobacteria associated with ↑mental component and pain threshold Actinomycetales associated inversely with depression Desulfohalobiaceae and Methanobacteriaceae associated with transit |
| Labus et al, 201798 | 29 IBS, 23 HV | NA | Fecal | GBA | No correlations between anxiety or depression symptom scores and microbial parameters; Clostridia and Bacteroidia correlated with sensory integration regions |
| Liu et al, 201699 | 40 IBS, 15 depression, 25 IBS and depression, 20 HV | NA | Fecal | GBA, immune | ↑Bacteroidetes and ↓Firmicutes in IBS-D, depression, and IBS-D with depression; Colonic mucosa inflammation associated with ↑ Bacteroides or Prevotella |
| Azpiroz et al, 2017100 | 79 IBS | scFOS vs pcbo | Fecal | GBA, sensation | scFOS reduced anxiety scores and increased fecal Bifidobacteria No significant difference in rectal sensory threshold for scFOS vs pcbo |
| Le Gall et al, 2011101 | 10 IBS, 13 UC, 22 HV | NA | Fecal | Fecal metabolites | Correlation between gut microbiota profile and metabolite composition |
| Heitkemper et al, 2018102 | 93 IBS | NA | Fecal | Permeability | Higher stool TFF3 associated with lower permeability and microbial diversity Christensenellaceae related inversely to stool TFF3 |
| Bednarska et al, 2017103 | 32 IBS, 15 HV | NA | Mucosal | Immune, permeability | Increased permeability to E coli strain HS and S typhimurium in IBS biopsy specimens vs controls ↑Plasma VIP in IBS vs HV ↑Tryptase and mast cells in IBS biopsy specimens vs HV |
| Valentin et al, 2017104 | 15 IBS-D | SBI | Duoden al brushing, fecal | Immune, permeability, metabolism | Bile acid synthesis, tryptophan metabolism, permeability, and stool microbiome not significantly different with SBI Changes in β diversity analysis, increased ↑ Proteobacteria Burkholderiales, Firmicutes Catonella, and unclassified genus organisms with SBI in duodenal microbiome |
| Ko et al, 2013105 | 53 IBS-D | Herbal (GJS), probiotic (Duolac7S; Cell Biotech Co, Ltd, Gimpo, Korea), pcbo | Fecal | Permeability | GJS with DuoLac7 ↑ B lactis, L rhamnosus, L plantarum No significant difference observed in permeability |
| Crouzet et al, 20136 | 3 IBS-C, 2 HV | NA | Fecal | Rectal sensitivity | IBS with rectal hypersensitivity have ↓bifidobacteria, ↑Enterobacteriaceae, and ↑H2-using sulfide-producing bacteria vs HV |
| Shulman et al, 2017106 | 103 IBS children | Fiber vs placebo | Fecal | GBA, permeability | No differences in psychological symptoms, permeability, or microbiome between groups |
| Compare et al, 2017107 | 10 IBS-D, 10 HV (ex vivo) | LC-DG, postbiotic | Mucosal | Immune | ↑IL1α, IL6, and IL8 messenger RNA, TLR-4 protein expression with ↓IL10 messenger RNA levels in PI-IBS-D vs HV LC-DG and PB ↓messenger RNA levels of proinflammatory cytokines and TLR-4 but ↑IL10 after LPS stimulation |
| Hustoft et al, 2017108 | 20 IBS-D or IBS-M | Low FODMAP diet, FOS vs pcbo | Fecal | Immune, SCFA | ↓IL6 and IL8, fecal bacteria (Actinobacteria, Bifidobacterium, Faecalibact erium prausnitzii), total SCFAs, and n-butyric acid on LFD FOS supplement then ↑levels of these bacteria, but cytokines and SCFAs unchanged |
| McIntosh et al, 2017109 | 37 IBS | Low vs high FODMAP | Fecal | Urinary metabolites | Significant correlations between relative bacterial abundance and symptoms and urinary metabolites (histamine, p-hydroxybenzoic acid) |
| Sundin et al, 2015110 | 11 PI-IBS, 10 HV (ex vivo) | NA | Mucosal | Immune | IL1β ↑ in PI-IBS vs HV after stimulation with Subdoligranulum variabile; IL10 ↓ in HV vs PI-IBS after stimulation with Eubacterium limosum |
| Sundin et al, 2015111 | 13 PI-IBS, 19 IBS, 16 HV | NA | Fecal, mucosal | Immune, GBA | Naive CD8+ CD45RA+ intraepithelial lymphocytes and lamina propria lymphocytes correlated negatively with mucosal microbial diversity Fecal microbial diversity correlated negatively with HADS |
| Pinto-Sanchez et al, 2017112 | 44 IBS | BL vs pcbo | Fecal | GBA, immune, urinary metabolites, neurotransmitter s, and neurotrophins | BL ↓depression and was associated with ↓limbic reactivity No difference in fecal microbiota, serum markers of inflammation, neurotrophins, and neurotransmitters Reduced urine methylamines and aromatic amino acid metabolites with BL |
| Parthasarathy et al,217 2017 | 25 CC, 25 HV | NA | Fecal | Transit | Reproducibility of fecal microbiota lower in normal transit vs slow-transit constipation |
| Parthasarathy et al, 2016113 | 25 CC, 25 HV | NA | Fecal, mucosal | Transit | Fecal microbiota profile associated with colonic transit; genera from Firmicutes correlated with faster colonic transit |
| Tian et al, 2017114 | 60 STC | FMT | NA | Transit | FMT associated with faster transit vs control treatment |
BL, Bifidobacterium longum NCC3001; cc, chronic constipation; FODMAP, fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; GBA, gut–brain axis; HADS, Hospital Anxiety and Depression Scale; HV, healthy volunteer; IBS-M, irritable bowel syndrome mixed subtype; LC-DG, Lactobacillus casei DG; LFSD, low fermentable substrate diet; LPS, lipopolysaccharide; pcbo, placebo; PI-IBS, postinfectious irritable bowel syndrome; SBI, serum-derived bovine immunoglobulin/protein isolate; scFOS, short-chain fructooligosaccharide; TFF3, urine trefoil factor 3.