Study On The Changes Of Intestinal Flora In Patients With Chronic Heart Failure

Background:Chronic heart failure is the final stage of cardiovascular disease,which has the clinical characteristics of high morbidity and mortality.The symptoms of organ ischemia and congestion induced by heart failure are especially significant in the intestinal tract with rich blood supply.Therefore,the changes of intestinal flora,intestinal barrier dysfunction,the imbalance of short-chain fatty acids and trimethylamine N-oxide,which are metabolites of intestinal flora,may be related to the occurrence and development of heart failure.Objective:The purpose of this study was to study the characteristics of intestinal flora changes in patients with heart failure by 16 SRNAAmplifier sequencing.Methods:27 subjects were divided into ischemic cardiomyopathy heart failure group(n = 10),dilated cardiomyopathy heart failure group(n = 11)and healthy control group(n = 6)from October 2017 to December 2019 in Shaanxi Provincial people’s Hospital.The healthy control group clearly excluded hypertension,coronary heart disease,heart failure and other cardiovascular diseases;the intestinal tract of patients with heart failure of different causes were in line with the diagnostic criteria of Chinese Heart failure guidelines 2018.5g of stool was left to extract DNA from stool,and gene sequence,Illumina Miseq sequencing platform was obtained by 16 s RNA amplifiers to analyze α diversity,βdiversity and strain difference analysis to obtain biological information.Based on αdiversity index and β diversity index,Wilcoxon rank sum test was used to compare the pairwise among the three groups and draw a box diagram.The differences of species diversity,abundance and microflora structure among the three groups were reflected respectively,and p<0.05 was taken as the significant difference index.In LEfse analysis,nonparametric factor Kruskal-Wallis rank sum test and Wilcoxon rank sum test combined with linear discriminant analysis LDA were used to show significant strains among the three groups.On the basis of the significant differences among the three groups in LEfse analysis,the differences of bacteria in pairwise comparison among the three groups were found by DESeq analysis.Results:1954067 high quality sequences were obtained from 27 samples in this study.After annotation,1399 kinds of OTU,were obtained to draw the dilution curve of each sample,and finally showed a gentle trend,indicating that the sequencing depth of the visible samples was appropriate.At the phymul level,Bacteroides and Firmicutes were the dominant bacteria in each sample,and the bacteria with the highest abundance at the genus level were Bacteroides in ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group,and Faecalibacterium in the healthy control group.The diversity of ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group was significantly lower than that of healthy control group(simpson index p=0.031,p=0.02,respectively)and there was statistical significance,while the abundance of intestinal microflora in the three groups was as follows: ischemic cardiomyopathy heart failure group >healthy control group >dilated cardiomyopathy heart failure group,and there was no significant difference between ischemic cardiomyopathy heart failure group,dilated cardiomyopathy heart failure group and healthy control group.There was no significant difference in diversity and abundance between ischemic cardiomyopathy group and dilated cardiomyopathy heart failure group.In the comparison of β diversity,there was significant separation between healthy control group and ischemic heart failure group and dilated cardiomyopathy heart failure group in PCOA map based on Bray Curtis distance,while the samples from ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group showed scattered distribution,and no aggregation phenomenon was observed.The statistical analysis of the difference of β diversity index among different groups showed that there were significant differences between healthy control group and ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group(q =0.035,q= 0.033),and there was significant difference between healthy control group and ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group.At the genus level,there were 12 and 17 species of bacteria in ischemic cardiomyopathy heart failure group,dilated cardiomyopathy heart failure group and healthy control group by DESeq2 analysis,and 9 and 14 species were enriched in ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group,respectively.Veillonella and Enterococcus were found in 9 kinds of enrichment bacteria in ischemic cardiomyopathy heart failure group,while Veillonella Enterococcus and Ruminococcus in 14 species in dilated cardiomyopathy heart failure group belonged to the top 20 species of total sample genera.Conclusion:1.At the gate level,Bacteroides and Firmicutes are the dominant bacteria in all groups.2.The diversity of intestinal bacteria in ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group is significantly lower than that in healthy control group.at the same time,the flora structure of ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group changed compared with healthy control group.There was no significant difference in intestinal microflora diversity and flora structure between ischemic cardiomyopathy heart failure group and dilated cardiomyopathy heart failure group,but compared with healthy control group.3.Veillonella and Enterococcus were enriched in the ischemic cardiomyopathy heart failure group,and Veillonella,Enterococcus and Ruminococcuswere enriched in the dilated cardiomyopathy heart failure group compared with the control group.