Exploring the effect of choroid plexus volume on white matter integrity and cognitive deficits in bipolar and unipolar depression

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Beatrice Bravi^1,2 (bravi.beatrice@hsr.it), Alessia Bortolotti¹, Margherita Biondi^1,3, Sara Poletti^1,2, Mariagrazia Palladini^1,2, Cristina Colombo^2,4, Francesco Benedetti^1,2; ¹IRCCS San Raffaele Scientific Institute, Division of Neuroscience, Psychiatry and Clinical Psychobiology Unit, ²Vita-Salute San Raffaele University, ³Department of General Psychology, Padova Neuroscience Center, University of Padova, ⁴IRCCS San Raffaele Scientific Institute, Mood Disorders Unit

Major depressive disorder (MDD) and bipolar disorder (BD) are leading causes of life-long disability. Persistent cognitive impairment even in euthymic phases impacts quality of life. Although both inflammation and white matter (WM) disruption were associated with cognitive impairment in mood disorders, a comprehensive picture of the underlying biological mechanisms is still missing. Given recent results highlighting the enlargement of choroid plexus (ChP) in mood disorders being correlated with peripheral inflammatory markers, we investigated ChP effect on WM integrity and cognitive deficits, exploring a mediation effect of WM on the relationship between ChP enlargement and cognitive deficits. ChP volumes were extracted through Freesurfer (37 depressed-BD, 40 depressed-MDD). DTI analyses (TBSS, FSL) were conducted to explore the association of ChP volumes with WM integrity, accounting for lithium treatment (BD), age, and sex. We evaluated the effect of ChP volume on six cognitive domains, gathered through Brief Assessment of Cognition in Schizophrenia (BACS). Lastly, we tested moderated mediation models setting diagnosis as moderator, extracted DTI measures as mediators, ChP volume as predictor and verbal fluency (VF) as outcome. ChP volume negatively associated with fractional anisotropy and positively with mean diffusivity (only in BD) and radial diffusivity (RD) in a widespread pattern of WM fibers. ChP volume significantly predicted VF. The moderated mediation model was significant, with only BD showing the indirect effect of ChP volume on VF mediated by RD. These results depicted disease-specific biological mechanisms underlying cognitive impairment in BD and MDD, proposing to deepen the role of immune-brain interface in BD.

Topic Area: METHODS: Neuroimaging