C-reactive protein-related cortical thickness changes and its association with resting-state functional connectivity alterations in major depressive disorder.

BACKGROUND: C-reactive protein (CRP) has emerged as a promising peripheral biomarker of neuroinflammatory processes implicated in the pathophysiology of major depressive disorder (MDD). We combined structural magnetic resonance imaging (MRI) with resting-state functional MRI to examine plasma CRP-related cortical thickness and resting-state functional connectivity (RSFC) changes.

METHODS: Seventy-six patients with MDD and 65 healthy controls (HCs) were included in this study. The association between whole-brain cortical thickness and plasma CRP levels in the total sample (MDD+ HC, n = 141) was investigated. Seed-to-voxel RSFC analysis was performed using plasma CRP level-related cortical regions as seeds.

RESULTS: Compared to the HC group, the MDD group showed significantly higher plasma CRP levels (p = 0.039). Higher plasma CRP levels were associated with cortical thinning in the prefrontal cortices and precentral gyrus, and cortical thickening in the left postcentral and right medial orbitofrontal gyrus. RSFC analysis showed a lower RSFC between the left dorsolateral prefrontal cortex and bilateral insula and between the precentral gyrus and superior parietal cortex, and higher RSFC between the dorsomedial prefrontal cortex and postcentral gyrus in MDD compared to HCs.

CONCLUSIONS: Our findings suggest that systemic inflammation may be associated with structural and functional disruption of emotion regulation and cognitive control networks in MDD.