胃癌高发区河西走廊水土及人体胃肠道中致癌菌群结构特征研究

Microorganism and gastric carcinogenesis are closely connected. The prevalence of Helicobacter pylori infection in gastric cancer is about 90%. Microorganisms have a central role in the processes of nitrogen forming highly carcinogenic nitrosamines. We found that the nitrite concentration in environment and H.pylori infection rate were higher than the national average. However, the precise mechanisms responsible for the two phenomena have not been clearly defined. We proposed that high abundance of H.pylori in environment and it break the balance of gut microbiota. It is also proposed that microbiota in enviroment and gut form nitrosamines more easliy. Therefore, the objective of this project is, by using qPCR to detect the level of H.pylori, nitrifying and denitrifying bacteria. Furthermore, we try to clarify the effects of the environment , dietary and H.pylori infection on the gut microbiome by 16S rRNA sequencing. In brief, this study is going to investigate the characteristics of microbiota in environment and Gut in high-incidence area for gastric carcinoma.

微生物与胃癌的发生密切相关，幽门螺旋杆菌（H.pylori）感染存在于90%的胃癌中；微生物全程参与了催化氮素→亚硝酸盐→强致癌物亚硝胺的合成过程。本项目前期研究显示，胃癌高发区河西走廊环境中亚硝酸盐含量和人群H.pylori感染率显著高于全国平均水平，但是该地区菌群结构与胃癌高发的关系尚不清楚。因此，本项目采用荧光定量PCR技术检测该地区水土中H.pylori和硝化细菌、反硝化细菌的丰度，分析致癌菌群结构特征；通过16S rRNA高通量测序明确该地区生活环境、饮食习惯、H.pylori感染对胃肠道微生物群落结构的影响，分析人体内参与亚硝化反应的菌群丰度，阐述胃癌高发区水土环境和人体胃肠道中致癌菌群结构特征，为进一步探讨微生物与胃癌的关系提供依据。

生物与胃癌的发生密切相关，幽门螺旋杆菌（H.pylori）感染存在于90%的胃癌中；微生物全程参与了催化氮素→亚硝酸盐→强致癌物亚硝胺的合成过程。本项目通过16S rRNA高通量测序，对河西走廊人群胃内菌群结构特征研究发现，在慢性胃炎、萎缩性胃炎及胃癌疾病发展进程这三个阶段中，菌群组成既有共有种类，也存在各自独有菌种，随着疾病的发展，微生物群落多样性明显减少，同时表现在物种数量减少、个体丰度分布均匀度降低、和群落复杂度降低这三个方面，另外感染幽门螺杆菌也会导致多样性降低，有意思的是在感染幽门螺杆菌后，慢性胃炎与萎缩性胃炎组成相似，而在胃癌组中微生物的组成具有统一的特征。总之，菌群结构特征与疾病的发生存在相关性。