Objective: To investigate the level differences of pro-inflammatory cytokines including soluble interleukin-6 receptor (SIL-6R), soluble tumor necrosis factor receptor type 1 (sTNF-R1), monocyte chemotactic protein-1(MCP-1) among bipolar disorder (BD),unipolar depression (UD) and normal controls (NC) groups;.To explore the inflammatory mechanism.in BD and UD.
Methods: Study subjects were BD or UD and normal controls (NC). Pro-inflammatory cytokines, including sIL-6R,sTNF-R1),MCP-1 were assessed in all subjects by enzyme-linked immunosorbent assays(ELISA). The multiple variant regression model was used to compare
pro-inflammatory cytokines between BD and UD,while controlling for the confounding factors including MADRS scores,YMRS scores, smoking, medical comorbidity, and body mass index(BMI).
Results: In all, 30 patients with BD, 35 patients with UD, and 130 NC were enrolled in the study. The BD group had significantly higher smoking rate, more medical comorbidity, higher BMI than the UD groups(p=0.033,0.012,0.040,all<0.05).The levels of sIL-6R, sTNF-R1, and MCP-1 in BD group were significantly higher than the UD group(p=0.021,0.023,0.035,all<0.05). Patients with comorbidities had higher levels of sIL-6R, sTNF-R1 and MCP-1(p =0.002,0.001,0.001,all<0.05). The levels of sIL-6R, sTNF-R1 and MCP-1 in BMI≥25 group were higher than BMI <25 group(p=0.031,0.026,0.030,all<0.05).Controlling for MADRS scores,YMRS scores, smoking, medical comorbidity, and BMI in the regression model,the results showed that the BD group had significantly higher levels of sIL-6R (p=0.002), sTNF-R1 (p = 0.006), and MCP-1(p = 0.012) than the UD group.
Conclusion s: Higher levels of sIL-6R, sTNF-R1, and MCP-1 were found in BD than in UD. These results may suggest a more severe inflammatory dysregulation in BD.