Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain or discomfort. Previous studies have illustrated that the gut microbiota might play a critical role in IBS, but the conclusions of these studies, based on various methods, were almost impossible to compare, and reproducible microorganism signatures were still in question. To cope with this problem, previously published 16S rRNA gene sequencing data from 439 fecal samples, including 253 IBS samples and 186 control samples, were collected and processed with a uniform bioinformatic pipeline. Although we found no significant differences in community structures between IBS and healthy controls at the amplicon sequence variants (ASV) level, machine learning (ML) approaches enabled us to discriminate IBS from healthy controls at genus level. Linear discriminant analysis effect size (LEfSe) analysis was subsequently used to seek out 97 biomarkers across all studies. Then, we quantified the standardized mean difference (SMDs) for all significant genera identified by LEfSe and ML approaches. Pooled results showed that the SMDs of nine genera had statistical significance, in which the abundance of Lachnoclostridium, Dorea, Erysipelatoclostridium, Prevotella 9, and Clostridium sensu stricto 1 in IBS were higher, while the dominant abundance genera of healthy controls were Ruminococcaceae UCG-005, Holdemanella, Coprococcus 2, and Eubacterium coprostanoligenes group. In summary, based on six published studies, this study identified nine new microbiome biomarkers of IBS, which might be a basis for understanding the key gut microbes associated with IBS, and could be used as potential targets for microbiome-based diagnostics and therapeutics.

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Objective: To investigate the inhibitory effect and mechanism of Wei Chang An pill (WCA) on ulcerative colitis (UC). Methods: A 2,4,6-trinitro-benzenesulfonic acid (TNBS)-induced UC model was established, and WCA was administered orally for 1 week. Body weight, colon length, disease activity index (DAI) score, and colon mucosa damage index (CMDI) score were recorded. Cytokine expression in lipopolysaccharide (LPS)-stimulated THP-1 cells was evaluated to determine the anti-inflammatory effects of WCA and its active ingredients. Immunohistochemistry and immunofluorescence were performed to detect the expression of epithelial-mesenchymal transition (EMT) markers E-cadherin and vimentin in rat UC and WCA groups, and in Caco-2 cells stimulated with conditioned medium (CM) from THP-1 cells, with or without LPS or WCA. Results: WCA significantly inhibited body weight loss, decreased DAI and CMDI scores, blocked colon length shortening, and improved histological damage in UC rats. Furthermore, both myeloperoxidase (MPO) activities and cytokine expression in UC tissues were significantly suppressed by WCA as well. In THP-1 cells, the mRNA expression of interferon-inducible protein (IP)-10, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and NF-κB inhibitor α (IκBα) was significantly suppressed by WCA and its active ingredients. E-cadherin expression in UC rats and CM-stimulated Caco-2 cells was downregulated and vimentin expression was upregulated, whereas both were blocked when administered with WCA. Conclusions: Our data showed that WCA alleviated UC progression by inhibiting inflammation-induced EMT progression. Graphical abstract: http://links.lww.com/AHM/A56