Differences In Species Composition And Metabolic Pathways Of Intestinal Flora In Patients With Depression

ObjectivesObserve the differences in intestinal microbial composition,metabolic pathways and clinical symptoms between patients with severe depressive episodes and healthy people,and further explore the influence of intestinal flora composition and differential metabolic pathways on the pathogenesis of depression in patients with severe depressive episodes.Material and methodsSelected 24 patients with depression(depression group)who were in the outpatient and inpatient departments of Shenzhen Kangning Hospital from January 2018 to January2019 and healthy volunteers in the surrounding communities of Shenzhen Kangning Hospital(control group)26 For example,the shotgun metagenomic sequencing method was used to analyze the abundance and types of intestinal flora and gene function pathways of the depression group in the control group.Based on the analysis of microbial composition and functional pathways,a classification method based on random forest(RF)was also established to identify the gut microbiota as a biomarker of MDD.All data were statistically analyzed using SPSS 23.0.The two groups of general demographic data and eating habits data were compared by the chi-square test,and the measurement data were compared by independent sample t-test.The test standard was p<0.05.The data obtained by shotgun metagenomic sequencing,the abundance and species of bacteria were normalized(ie,normalized to 1 million sequencing sequences),and then R software was used for variance analysis and DESeq2 calculation.The independent t test was used for comparison between the two groups.The data obtained from the functional pathways annotated by KEGG uses R software for analysis of variance.Results1.A total of 24 depression patients(depression group)and 26 healthy controls were enrolled.There was no significant difference between the two groups in terms of age,gender,and BMI.(>0.05)2.In the depression group,the abundance and diversity of intestinal flora are reduced.At the class level,the levels of Actinomycetes,Negativicutes,and Coriobacteriia in the MDD group increased,while the levels of Cytophagia,Bacteroidia,Flavobacteriia,and Sphingobacteriia decreased.At the family level,the MDD group showed high levels of bacteria in 7 families(Micrococcales,Desulfovibrionales,Eggerthellales,Coriobacteriales,Acidaminococcales,Lactobacillales,Veillonellales),(Flavobacteriales,Sphingobacteriales,Cytophagales,Alteromonadales),and Bactomonadales.Among the17 genera with the highest enrichment,there are 5(Bifidobacterium,Eggerthella,Coriobacterium,Olsenella,Slackia,Atopobium)actinomycetes.At the level of the most increased intestinal bacteria in MDD patients,there are also Bifidobacterium adolescentis,Bifidobacterium longum,Bifidobacterium dentifolia,Bifidobacterium bifidobacterium,Bifidobacterium breve,Eggerthella lenta,Coriobacterium glomerans,Rothia mucilaginosa,Olsenella uli,Slackia heliotrinireducens,Lancefieldella parvula 11 genera actinomycetes.The course of the disease was positively correlated with Cytophagales,and the HCL-32 score was negatively correlated with Cytophagia,Sphingobacteriia,Flavobacteriia,Alteromonadales,Cytophagales,Sphingobacteriales,and Flavobacteriales.HAMD score was positively correlated with Bacteroidetes and Bacteroidia,and negatively correlated with Coriobacteriia and Alteromonadales.HAMA score was negatively correlated with Cytophagia,Alteromonadales,Cytophagales,Flavobacteriales.(p<0.05)3.A total of 23 KOs with significant differences were found.Among them,the Actinomycota with differences at the phylum level was positively correlated with K11533,K02008,K03293,and K06148(p<0.05),while the Bacteroides phylum was negative with K02008 and K02035.Correlation,positively correlated with 13 KOs pathways that were significantly increased in the healthy group(p<0.05).In patients with depression,the biosynthesis of branched chain amino acids(valine,isoleucine)was increased,and fatty acid synthesis was significantly decreased.ConclusionsThere are differences in bacterial species and functional pathways in patients with severe depression.Changes in intestinal bacterial species and functional pathways in depression patients may affect the onset of depression.