374. INTEGRATION ANALYSIS OF GUT MICROBIOME AND SERUM PROTEOME IN PATIENTS WITH UNIPOLAR AND BIPOLAR DEPRESSIVE EPISODES

Abstract Background Major depressive disorder (MDD) and Bipolar disorder (BD) are chronic mental diseases with related causes but different clinical symptoms. The clinical symptoms of BDD and MDD overlap greatly, which makes the diagnosis of BDD patients more subjective, high rate of misdiagnosis and missed diagnosis. Aims & Objectives The purpose of this study was to identify MDD and BDD using a combination of intestinal microbiome and serum proteome techniques, and to search for objective biomarkers of BDD. Method The subjects were selected from 15 patients with major depressive disorder (MDD group) and 19 patients with bipolar depressive disorder (BDD group) who were admitted to the First Hospital of Hebei Medical University from May 2021 to November 2022. General demographic data were collected, and the Hamilton Depression Scale (HAMD-24), Hamilton Anxiety Scale (HAMA) and other assessments were completed. Collect stool and blood samples from patients. 16S rRNA gene detection was performed on gut flora to analyze the structure and diversity of gut flora. 4D-Lable free technology was used to detect proteins in serum. ROC curve analysis was used to evaluate the diagnostic efficiency of the screened differential bacteria and proteins. Spearman correlation analysis was performed between the differential proteins and differential intestinal bacteria. Results There was no significant difference in the scores of clinical scales between the two groups except HAMA total scale and HAMA somatic factor anxiety scale (P < 0.05); The α-diversity and β-diversity were statistically significant between the two groups (all P < 0.05). There were 27 significant differences between BDD group and MDD group (P < 0.05; LDA > 3). ROC curve analysis was further carried out for bacteria with genus level difference. It was found that the areas of g__Bifidobacterium, g__un_f_Enterobacteriaceae and g__Clostridium_sensu_stricto_1 curves were 0.777, 0.814 and 0.721, respectively. 93 DEPs (differentially expressed express proteins) were screened between the two groups. Compared with the MDD group, 21 proteins were up-regulated and 72 proteins were down-regulated in the BDD group. ROC curve analysis of differential proteins showed that 13 proteins were found to be valuable in differential diagnosis of BDD (AUC > 0.7, P > 0.05). Annotation and enrichment analysis of KEGG signaling pathway showed that the differential protein signaling pathway was mainly concentrated in virus-protein interaction with cytokines and cytokine receptors, antiviral related pathway, cytokine - cytokine receptor interaction pathway, chemokine signaling pathway and complement and coagulation cascade signaling pathway. g__Megamonas, g__Lachnospira, g__Subdoligranulum and g__Veillonella, g__Dialister was negatively correlated with many proteins. g__Bifidobacterium was positively correlated with 4 proteins. Discussion & Conclusions The intestinal microbiota and serum protein were different in patients with unipoar and bipolar depressive disorder. There were 27 significant differences in intestinal microbiota and 93 significant differences in serum proteins between the two groups, among which 8 different intestinal microbiota and 13 different serum proteins had potential role in the unipoar and bipolar depressive disorder. There may be interaction between intestinal microbes and serum proteins.