Abnormal bile acid metabolism is an important feature of gut microbiota and fecal metabolites in patients with slow transit constipation.

Destructions in the intestinal ecosystem are implicated with changes in slow transit constipation (STC), which is a kind of intractable constipation characterized by colonic motility disorder. In order to deepen the understanding of the structure of the STC gut microbiota and the relationship between the gut microbiota and fecal metabolites, we first used 16S rRNA amplicon sequencing to evaluate the gut microbiota in 30 STC patients and 30 healthy subjects. The α-diversity of the STC group was changed to a certain degree, and the β-diversity was significantly different, which indicated that the composition of the gut microbiota of STC patients was inconsistent with healthy subjects. Among them, Bacteroides, Parabacteroides, Desulfovibrionaceae, and Ruminiclostridium were significantly upregulated, while Subdoligranulum was significantly downregulated. The metabolomics showed that different metabolites between the STC and the control group were involved in the process of bile acids and lipid metabolism, including taurocholate, taurochenodeoxycholate, taurine, deoxycholic acid, cyclohexylsulfamate, cholic acid, chenodeoxycholate, arachidonic acid, and 4-pyridoxic acid. We found that the colon histomorphology of STC patients was significantly disrupted, and TGR5 and FXR were significantly downregulated. The differences in metabolites were related to changes in the abundance of specific bacteria and patients' intestinal dysfunction. Analysis of the fecal genomics and metabolomics enabled separation of the STC from controls based on random forest model prediction [STC vs. control (14 gut microbiota and metabolite biomarkers)-Sensitivity: 1, Specificity: 0.877]. This study provided a perspective for the diagnosis and intervention of STC related with abnormal bile acid metabolism.

Fan Y ，Xu C ，Xie L ，Wang Y ，Zhu S ，An J ，Li Y ，Tian Z ，Yan Y ，Yu S ，Liu H ，Jia B ，Wang Y ，Wang L ，Yang L ，Bian Y ... -  《Frontiers in Cellular and Infection Microbiology》

Analysis of Gut Microbiome and Metabolite Characteristics in Patients with Slow Transit Constipation.

Slow transit constipation (STC) is a type of functional constipation in which colon transit time is extended as a result of a reduction in the high amplitude of colon contraction activity. The utility of gut microbiome and metabolite characteristics in patients with STC is rarely studied. Short-chain fatty acids (SCFAs) enhance colonic fluid and sodium absorption and thus may aggravate the symptoms of STC. However, the content and role of SCFAs in constipation patients are not clear. We speculate that gut microbiome and SCFAs in the colon of STC patients may be abnormal and linked to the underlying mechanism of STC. This observational study is registered at ClinicalTrials.gov (NCT02984969). The high-throughput sequencing was used to analyze the diversity and composition of fecal microbial communities. Gas chromatography-mass spectrometry (GC-MS) was used to determine the properties and concentrations of the SCFAs in the two groups. The Shannon diversity and Simpson diversity of the gut microbiome were significantly greater in the STC group than the control group. The two groups also showed significant differences in the species composition of the gut microbiome at different classification levels. The results of GC-MS showed that the acetate concentrations in the STC group were significantly reduced compared with the control group, but the other five types of SCFAs and total SCFAs showed no significant difference between groups. ROC curve analyses revealed that the AUC of Acetate (AUC = 0.758) was higher than Propionate (AUC = 0.660). The largest AUC of gut microbiome for predicting STC was Prevotella (AUC = 0.807). Correlation analysis showed a positive correlation between the concentration of Ruminococcus and Disease history (rs = 0.519). Meanwhile, a positive correlation between the concentration of Roseburia and Acetate (rs = 0.606) or Butyrate (rs = 0.543) was found. We found significant differences between the STC and control groups in the main components of the gut microbiome, with greater diversity in the STC group and differences between the groups in species composition at different classification levels. These different microbiome and metabolite may be valuable biomarkers for STC.

Tian H ，Chen Q ，Yang B ，Qin H ，Li N ... -  《-》

Transdermal Administration of Volatile Oil from Citrus aurantium-Rhizoma Atractylodis Macrocephalae Alleviates Constipation in Rats by Altering Host Metabolome and Intestinal Microbiota Composition.

The Citrus aurantium- (ZhiShi, ZS-) Rhizoma Atractylodis Macrocephalae (BaiZhu, BZ) pairs are often found in herbal formulas for constipation. The volatile oils of ZS and BZ (ZBVO) have good pharmacological activity against constipation, but the mechanism for treatment of slow transit constipation (STC) remains unclear. A rat model using diphenoxylate tablets was constructed to investigate if transdermal administration of ZBVO would mediate intestinal microorganisms and fecal metabolites and improve STC symptoms. The regulatory effects of ZBVO at 0.15, 0.30, and 0.60 mL kg-1 d-1 on STC rats were assessed by measuring fecal water content, intestinal propulsion rate, histopathology, expression of gastrointestinal hormones, brain and intestinal peptides, and inflammatory factors. The changes in intestinal flora of STC rats were analyzed by 16S rRNA gene sequencing. Moreover, the untargeted fecal metabolomics analysis was performed by ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF-MS) technology. The results showed that ZBVO had a modulating effect on STC by increasing the fecal water content and intestinal propulsion rate. Transdermal administration of ZBVO decreased serum levels of interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) and increased the levels of gastrin (GAS) and substance P (SP). In addition, ZBVO increased 5-hydroxytryptamine (5-HT) levels and decreased vasoactive intestinal peptide (VIP) levels in colon and hippocampus tissues. The results of intestinal microbiota showed that ZBVO improved the diversity and abundance of intestinal microbiota and changed the community composition by decreasing Romboutsia and increasing Proteobacteria, Allobaculum, and Ruminococcaceae. And the feces metabolomics found that nicotinate and nicotinamide metabolism, purine metabolism, citrate cycle (TCA cycle), pyruvate metabolism, arachidonic acid metabolism, pyrimidine metabolism, and primary bile acid biosynthesis were modulated. These findings suggest that ZBVO can alleviate STC symptoms by promoting intestinal peristalsis, increasing fecal water content, regulating gastrointestinal hormone level, reducing the inflammatory response, and regulating brain and intestinal peptides after transdermal administration. And structural changes in the intestinal microbiota are closely related to host metabolism and intestinal microbiota destroyed in STC modeling could be significantly improved by the ZBVO, which provides a reference for the development of aromatic drug macrohealth products.

Wang L ，Wang F ，Zhang X ，Chen Q ，Xu J ，Li H ，Li F ，Yang M ... -  《-》

Fecal metabonomics combined with 16S rRNA gene sequencing to analyze the changes of gut microbiota in rats with kidney-yang deficiency syndrome and the intervention effect of You-gui pill.

A myriad of evidence have shown that kidney-yang deficiency syndrome (KYDS) is associated with metabolic disorders of the intestinal microbiota, while TCMs can treat KYDS by regulating gut microbiota metabolism. However, the specific interplay between KYDS and intestinal microbiota, and the intrinsic regulation mechanism of You-gui pill (YGP) on KYDS' gut microbiota remains largely unknown so far. In the present study, fecal metabonomics combined with 16S rRNA gene sequencing analysis were used to explore the mutual effect between KYDS and intestinal flora, and the intrinsic regulation mechanism of YGP on KYDS's gut microbiota. Rats' feces from control (CON) group, KYDS group and YGP group were collected, and metabolomic analysis was performed using 1H NMR technique combined with multivariate statistical analysis to obtain differential metabolites. Simultaneously, 16S rRNA gene sequencing analysis based on the Illumina HiSeq sequencing platform and ANOVA analysis were used to analyze the composition of the intestinal microbiota in the stool samples and to screen for the significant altered microbiota at the genus level. After that, MetaboAnalyst database and PICRUSt software were apply to conduct metabolic pathway analysis and functional prediction analysis of the screened differential metabolites and intestinal microbiota, respectively. What's more, Pearson correlation analysis was performed on these differential metabolites and gut microbiota. Using fecal metabonomics, KYDS was found to be associated with 21 differential metabolites and seven potential metabolic pathways. These metabolites and metabolic pathways were mainly involved in amino acid metabolism, energy metabolism, methylamine metabolism, bile acid metabolism and urea cycle, and short-chain fatty acid metabolism. Through 16S rRNA gene sequencing analysis, we found that KYDS was related to eleven different intestinal microbiotas. These gut microbiota were mostly involved in amino acid metabolism, energy metabolism, nervous, endocrine, immune and digestive system, lipid metabolism, and carbohydrate metabolism. Combined fecal metabonomics and 16S rRNA gene sequencing analysis, we further discovered that KYDS was primarily linked to three gut microbiotas (i.e. Bacteroides, Desulfovibrio and [Eubacterium]_coprostanoligenes_group) and eleven related metabolites (i.e. deoxycholate, n-butyrate, valine, isoleucine, acetate, taurine, glycine, α-gluconse, β-glucose, glycerol and tryptophan) mediated various metabolic disorders (amino acid metabolism, energy metabolism, especially methylamine metabolism, bile acid metabolism and urea cycle, short-chain fatty acid metabolism. nervous, endocrine, immune and digestive system, lipid metabolism, and carbohydrate metabolism). YGP, however, had the ability to mediate four kinds of microbes (i.e. Ruminiclostridium_9, Ruminococcaceae_UCG-007, Ruminococcaceae_UCG-010, and uncultured_bacterium_f_Bacteroidales_S24-7_group) and ten related metabolites (i.e. deoxycholate, valine, isoleucine, alanine, citrulline, acetate, DMA, TMA, phenylalanine and tryptophan) mediated amino acid metabolism, especially methylamine metabolism, bile acid metabolism and urea cycle, short-chain fatty acid metabolism, endocrine, immune and digestive system, and lipid metabolism, thereby exerting a therapeutic effect on KYDS rats. Overall, our findings have preliminary confirmed that KYDS is closely related to metabolic and microbial dysbiosis, whereas YGP can improve the metabolic disorder of KYDS by acting on intestinal microbiota. Meanwhile, this will lay the foundation for the further KYDS's metagenomic research and the use of intestinal microbiotas as drug targets to treat KYDS.

Chen R ，Wang J ，Zhan R ，Zhang L ，Wang X ... -  《-》

Zhizhu decoction alleviates slow transit constipation by regulating aryl hydrocarbon receptor through gut microbiota.

Wen Y ，Zhan Y ，Tang S ，Liu F ，Wu R ，Kong P ，Li Q ，Tang X ... -  《-》