Gastric Mucosal-associated Microbiota In The Patient With Gastric Intraepithelial Neoplasias

Backgound:We have little knowledge about the distribution of the gastric microbiota and its function. It is unclear that whether the microbiota in stomach is altered among patients with gastric pre-cancer and whether the local dysbiosis in stomach participates in the progression of gastric neoplasia. There are no published studies on gastric microbiota in pre-cancer lesions at present, especially in patients with gastric intraepithelial neoplasia(GIN).Aims:To describe profiling of the gastric bacterial microbiota in healthy person and patients with gastric intraepithelial neoplasia.Methods:GIN patients without any treatment and healthy subjects with normal gastric mucosa were enrolled in this study from Oct 2013 to Oct 2014 in the Chinese PLA general hospital. Samples were collected by endoscopic biopsies from gastric antrum, corpus and lesion tissue respectively. Total genomic DNA from each sample was extracted with the QIAamp DNA Mini kit (Qiagen) combined with the glass beat beater method. The gastric mucosal-associated bacterial 16S rDNA V4 was sequenced by the Illumina MiSeq sequencing platform. Sequences were analyzed with the QIIME software and UPARSE pipeline. Clustering of samples was evaluated by principal coordinate analysis (PCoA) and unweighted pair group method with arithmetic mean (UPGMA) clustering.Both HC and GIN group were divided into three subgroups, according to the relative abundance of H. pylori.Result:Thirty healthy subjects and 25 GIN patients were finally enrolled in this study, including 10 low-grade intraepithelial neoplasia (LIN) patients and 15 high-grade intraepithelial neoplasia (HIN) patients. There are no significant differences in demographic data. The average number of OTUs in GIN group was significantly lower than that of the healthy control group (HC) (P<0.05),while there was no significant difference in the average number of OTUs between LIN and HIN group (P>0.05). The relative abundance of Firmicutes,Bacteroidetes,Fusobacteria phylum in pre-cancer group was noticeably higher than that in control group.Meanwhile, Proteobacteria,Cyanobacteria, Acidobacteria, Planctomycetes, Nitrospirae phylum in pre-cancer group was obviously lower. By analyzing the two groups at genera level, there was no significant difference in the median abundance of Helicobacter genera between the tow groups (P>0.05). the Lactobacillus genera, Streptococcus genera, Prevotella genera, Veillonlla genera, Heamphilus genera, Halomonas genera, and Actinobacillus genera were obviously higher, while the Acinetobacter genera, Zoogloea genera, Sphingobium genera were significantly lower in GIN group compared with HC group. Hierarchic classification showed that the higher of H.pylori abundance, the lower of microbiota diversity.The relative abundance of Firmicutes phylum and Lactobacillus genera in GIN patients were noticeably higher,while Planctomycetes phylum, Nitrospirae phylum and Zoogloea genera, Sphingobium genera were obviously lower in all the three subgroups.In PCoA/UPGMA cluster analysis, the GIN group and the HC group were separated apparently. However, the composition of microbiota in LIN group and HIN group was similar.Conclusion:The diversity of gastric mucosal-associated microbiota in patients with GIN was significantly lower compared with normal volunteers, Moreover, the composition of stomach microbiota was also noticeably different between the two groups.The altered microbiota and the progression of gastric neoplasia may have a certain relationship.