Published online Jul 7, 2019. doi: 10.3748/wjg.v25.i25.3242
Peer-review started: April 15, 2019
First decision: May 16, 2019
Revised: June 2, 2019
Accepted: June 8, 2019
Article in press: June 9, 2019
Published online: July 7, 2019
Ulcerative colitis (UC) is considered to be closely associated with alteration of intestinal microorganisms. According to the traditional Chinese medicine (TCM) theory, UC can be divided into Pi-Xu-Shi-Yun syndrome (syndrome of spleen deficiency and dampness, PXSY) and Da-Chang-Shi-Re syndrome (syndrome of dampness-heat in the large intestine, DCSR). PXSY syndrome is a deficiency syndrome, while the DCSR syndrome is a sthenia syndrome. However, the relationships among gut microbiota, TCM syndromes, and UC pathogenesis are unclear.
The majority of studies have focused on the relationship between intestinal microbiota and the onset of UC, and the contribution of gut microbiota in these two distinct TCM syndromes is still unclarified. This study aimed to compare the difference in microbial composition and function between PXSY and DCSR syndromes to determine the molecular mechanism of TCM in UC by investigation of the gut microbiota.
The objective of this study was to investigate the role of gut microbiota in UC and the distinction of microbiota dysbiosis between PXSY and DCSR syndromes.
We analysed gut microbiome composition of stool samples by 16S rRNA pyrosequencing. We assessed the beta diversity by UniFrac analysis. We also processed the high-throughput se-quencing reads with QIIME, and further predicted biological functions using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.
We determined the composition of gut bacterial communities in 93 stool samples (30 healthy controls, 32 patients with PXSY syndrome, and 31 patients with DCSR syndrome) by 16S rRNA pyrosequencing. Beta diversity showed that the composition of the microbiota was different among the three groups. We found that Porphyromonadaceae, Rikeneliaceae, and Lach-nospiraceae significantly decreased while Enterococcus, Streptococcus, and other potential pathogens significantly increased in UC patients compared to healthy subjects at the family level. We further found that Parabacteroides, Dorea, and Ruminococcus decreased while Faecalibacterium showed increased abundance in UC compared to healthy controls at the genus level. Five differential taxa were identified between PXSY and DCSR syndromes. We observed a significantly increased abundance of Streptococcus in DCSR patients at the genus level, while Lachnoclostridium increased in PXSY patients. Additionally, we found that the differential fun-ctional pathways of the gut microbiome between the PXSY and DCSR groups mainly included lipid metabolism, immunity, and the metabolism of polypeptides.
The present study identified that the gut microbiota is different between patients with PXSY syndrome and those with DCSR syndrome. The genus Streptococcus is significantly more abundant in DCSR patients than in PXSY patients, while Lachnoclostridium increases in PXSY patients. The microbial analysis of the two TCM syndromes essentially reflects different immune activities in the human body, but they all point to promotion of inflammation in the gut.
The relationship between TCM syndromes and intestinal flora is an interesting and important research topic. Our study preliminarily explored the characteristics and differences of intestinal flora of patients with two different TCM syndrome. Further studies are required to confirm our findings and to clarify the precise mechanism of intestinal flora characteristics related to TCM deficiency and positive syndrome.