Abstract: Background　Coronary heart disease（CHD） is one of the most common causes of deaths in developed and developing countries．The composition of gut microbiota plays an important role in the pathological process of CHD．More and more evidences show that the imbalance of gut microbiota induce lipid metabolism disorder，low-grade inflammation，insulin resistance and elevated blood pressure，increasing the risk of CHD．Objective　To explore the risk factors for CHD by examining the characteristics（including composition and diversities） of gut microbiota in CHD patients，providing a new diagnostic and treatment method for such patients．Methods　This study was conducted in the First Affiliated Hospital of Xinxiang Medical University during July 2016 to June 2017 between 62 cases of CHD from CCU and Cardiovascular Department and 30 health examinees（control group）．CHD patients were divided into mild CHD group（n=27） and moderate-to-severe CHD group（n=35） by Gensini score．Fecal samples were collected，from which DNA was extracted and amplified by polymerase chain reaction in the bacterial 16S rDNA V3 region，and the final PCR amplification products were analyzed by bioinformatics．Results　Mild CHD group，moderate-to-severe CHD group and control group had no significant differences in PE_reads，Nochimera，AvgLen，GC and Effective（P>0.05）．ACE，Chao1，Shannon and Simpson differed significantly among mild and moderate-to-severe CHD groups and control group（P<0.05），and they were much lower in the former two compared with the latter one showed by pairwise comparisons（P<0.05）．The relative abundances of bacteroidetes and proteobacteria differed significantly among control group and mild and moderate-to-severe CHD groups（P<0.05），and the relative abundances of bacteroidetes in the former one were much higher than the latter one，the relative abundances of proteobacteria in the former one were much lower than the latter one （P<0.05）．The relative abundances of bacteroidia and fusobacteria varied significantly among control group and mild and moderate-to-severe CHD groups（P<0.05），and the relative abundances of bacteroidia were much lower in the moderate-to-severe CHD group compared with the mild CHD group，and the relative abundances of fusobacteria were much higher in the moderate-to-severe CHD group compared with the mild CHD group，and and the relative abundances of bacteroidia were much lower in mild CHD group compared with the control group，and the relative abundances of fusobacteria were much higher in mild CHD group compared with the control group（P<0.05）．Mild and moderate-to-severe CHD groups and control group showed significant differences in the relative abundance of bacteroides （P<0.05）．Moderate-to-severe CHD group had much lower relative abundance of bacteroides than the mild CHD group and control group，as did the mild CHD group compared with the control group（P<0.05）．Metastats analysis showed that significant differences were found between the control group and mild CHD group in terms of the relative abundances of bacteroides，Barnesiella，Desulfovibrio，Escherichia Shigella and Phascolarctobacterium（P<0.05），and between the control group and moderate-to-severe CHD group in terms of the relative abundances of Barnesiella，Dialister，Flavonifractor，Parasutterella and Phascolarctobacterium（P<0.05），and between the mild and moderate-to-severe CHD groups in terms of the relative abundances of Desulfovibrio，Dialister，Escherichia-Shigella，Flavonifractor，and Paraprevotella（P<0.05）．Conclusion　Changes in the diversity and structure of gut microbiota are risk factors for CHD．Therefore，regulation of gut microbiota and fecal microbiota transplantation may be used as the new treatments for CHD．

Key words: Coronary disease, Biodiversity, Computational biology, Intestinal flora, Multilocus sequence typing

摘要： 背景　冠心病是发达国家及发展中国家最常见的死亡原因之一，肠道菌群的组成在冠心病的病理过程中起重要作用，越来越多证据表明，肠道菌群失调可导致脂质代谢紊乱、低度炎性反应、胰岛素抵抗、血压升高等，进而增加冠心病风险。目的　通过检测冠心病患者肠道菌群结构及多样性，了解其肠道菌群特点，进一步寻找冠心病危险因素，为冠心病患者提供新的诊疗方法。方法　选取2016年7月—2017年6月入住新乡医学院第一附属医院心血管内科及心脏重症监护病房（CCU）的冠心病患者62例，应用Gensini评分将其分为轻度组27例，中重度组35例；同时选取同期于本院体检的30例健康者作为对照组。采集研究对象的粪便样本，提取粪便样本的DNA并对其进行细菌16S rDNA V3区的聚合酶链式反应（PCR）扩增，对最终的PCR扩增产物进行生物信息学分析。结果　三组原始PE reads数目（PE_reads）、去除嵌合体后有效序列数目（Nochimera）、有效序列平均长度（AvgLen）、有效数据的GC百分比含量（GC）、Nochimera与PE_reads的百分比（Effective）比较，差异均无统计学意义（P>0.05）。三组ACE、Chao1、Shannon、Simpson指数比较，差异均有统计学意义（P<0.05）；其中，轻度组与中重度组ACE、Chao1、Shannon、Simpson指数均低于对照组（P<0.05）。三组拟杆菌门、变形菌门相对丰度比较，差异均有统计学意义（P<0.05），其中中重度组拟杆菌门相对丰度低于对照组，变形菌门相对丰度高于对照组（P<0.05）；三组拟杆菌纲、梭菌纲相对丰度比较，差异均有统计学意义（P<0.05），其中中重度组拟杆菌纲相对丰度低于轻度组、梭菌纲相对丰度高于轻度组，轻度组拟杆菌纲相对丰度低于对照组、梭菌纲相对丰度高于对照组（P<0.05）；三组拟杆菌属相对丰度比较，差异有统计学意义（P<0.05），其中中重度组相对丰度低于轻度组和对照组，轻度组相对丰度低于对照组（P<0.05）。Metastats差异分析结果显示对照组与轻度组拟杆菌属、巴斯德菌属、脱磷弧菌属、埃希杆菌-志贺杆菌属、考拉杆菌属菌落相对丰度比较，差异均有统计学意义（P<0.05）；对照组与中重度组巴斯德菌属、Dialister属、黄杆菌属、Parasutterella属、考拉杆菌属菌落相对丰度比较，差异均有统计学意义（P<0.05）；轻度组与中重度组脱磷弧菌属、Dialister属、埃希杆菌-志贺杆菌属、黄杆菌属、帕拉普菌属菌落相对丰度比较，差异均有统计学意义（P<0.05）。结论　肠道菌群多样性、结构的改变，是冠心病的危险因素，因此调节肠道菌群、粪菌移植等方法可能成为冠心病新的治疗方法。

关键词: 冠心病, 生物多样性, 计算生物学, 肠道菌群, 多位点测序分型