Characteristics Of Gut Microbiota In Patients With Transient Cerebral Ischemia And Cerebral Infarction

ObjectiveCerebral infarction(CI),a disease with high morbidity,recurrence,disability and mortality rates,has seriously endangered human health,while transient ischemic attack(TIA),which often precedes CI,is a warning sign of CI.Moreover,the current imaging examinations and conservation drug treatment or surgical treatment are the mainstays of current diagnosis and treatment for such cerebrovascular diseases.However,numerous survivors still suffer from varying degrees of loss of labor or even the inability to care for themselves after treatment.In order to determine the relationship of gut flora changes with TIA and CI,the study was conducted to dissect the gut microecological characteristics of healthy controls,TIA patients,and patients with initial(ICI)and recurrent CI(RCI),as well as their differences,thus providing a novel way of clinical diagnosis and treatment with microorganisms as the target.MethodsBased on the Illumina Mi Seq sequencing system,the 16 S r RNA sequencing technology was utilized for the paired-end sequencing of the 16 S r RNA gene V3-V4 region in the fecal microbial genome of 7 TIA patients,33 ICI patients,and 17 RCI patients,which were all admitted to the Department of Neurology of the First Affiliated Hospital of Jinan University,as well as 18 healthy adult controls(Con)undergoing physical examination in this hospital during the same period.Then,all the original sequences(input)measured were sequentially filtered,denoised,merged,and de-chimerized using the DADA2 package in the Qiime2 analysis program to obtain operational taxonomic units whose representative sequences were further compared with the Greengene database to collect species annotation information.Finally,the composition and corresponding Alpha and Beta diversities of gut microbes were analyzed in samples of each group on the basis of the annotation of species.Meanwhile,the characteristic species of each group were screened out as per Linear Discriminant Analysis Effect Size(LEfse).Also,the functions of gut flora in each group were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.Results1.The risk of CI,a multifactorial disease,shared a positive correlation with persistently elevated white blood cell levels,glucose concentration,creatinine concentration,and anion gap.However,the high level of high-density lipoprotein was a favorable factor for the early prevention of CI.2.At the phylum stratification level,the majority of gut microbes in the Con,TIA,ICI,and RCI groups were Firmicutes,Bacteroidetes,and Proteobacteria,with a total proportion of93.10%,95.13%,95.01%,and 97.09% respectively in each group.There existed a higher abundance of Firmicutes and a lower abundance of Bacteroidetes in the Con group than in the TIA,ICI,and RCI groups.Nevertheless,the abundance of Proteobacteria was significantly increased in the ICI and RCI groups in contrast to the Con and TIA groups.3.As reflected by the results of Alpha diversity analysis,no obvious difference was noted among the Con,TIA,ICI,and RCI groups in terms of Faith’s phylogenetic diversity,observed＿otu,and shannon indexes(P > 0.05),which suggested comparable microbial composition abundance and uniformity of these four groups.4.The results of Beta diversity analysis based on Bray Curtis distance and unweighted＿unifrac distance indicated that there were dramatically different community structures between the Con and ICI groups,the Con and RCI groups,and the TIA and ICI groups.However,the TIA group was insignificantly different from the Con group regarding the type and abundance of gut flora.5.LEf Se analysis manifested prominently different 10 species in the four groups at the phylum stratification level,including Acidobacteria phylum,Gemmonobacteria phylum,AD3 phylum,Synergistetes phylum,and Chloroflexi phylum in the RCI group,Proteobacteria phylum in the ICI group,Verrucomicrobia phylum,Fusobacterium phylum,and Cyanobacteria phylum in the Con group,and an unclassified phylum in the TIA group.6.The function prediction analysis of the microbial composition in each group exhibited that at the level of the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway(L2),both(antibacterial)drug resistance and carbohydrate metabolism functions of the TIA group were substantially weaker than those of the Con group,whilst the lipid metabolism function of the RCI group was signally stronger.In addition,the energy metabolism function of the ICI group was also observably weakened versus the Con group and the RCI group.At the level of the KEGG pathway(L3),compared to the Con group,the thiamine metabolism function was noticeably reduced in the RCI group.Meanwhile,carbon fixation in photosynthetic organisms,thiamine metabolism,and amino acid biosynthesis were markedly repressed but lipoic acid metabolism was conspicuously enhanced in the ICI group in comparison with the Con group.The four groups were not considerably different in terms of the remaining functions at the KEGG pathway(L2-L3)levels ConclusionCompared with healthy controls,the composition diversity of gut microflora did not evidently decrease in patients with TIA and CI,whereas marked changes in the relative abundance of gut microbiota,especially Proteobacteria,occurred in patients with CI.Moreover,noticeable differences in gut characteristics were noted between patients with ICI and RCI,illustrating that different microbial community structures might assume varying roles in the occurrence and even recurrence of CI.Based on this,taking gut flora as a therapeutic target may be a new therapeutic option to prevent or delay the occurrence and development of the disease.