Serotonergic deficits in dementia with Lewy bodies with concomitant Alzheimer's disease pathology: An 123I-FP-CIT SPECT study.

Abstract

To study the influence of concomitant Alzheimer's disease (AD) pathology in dementia with Lewy bodies (DLB) on dopamine transporter (DAT) and serotonin transporter (SERT) availability, using 123I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (123I-FP-CIT) single photon emission computed tomography (SPECT). Based on their cerebrospinal fluid biomarker profile, fifty-two patients with probable DLB were divided in a group with (DLB/AD+, N = 15) and without concomitant AD-pathology (DLB/AD-, N = 37). We conducted atrophy-corrected region of interest (ROI) analyses comparing binding ratios (BRs) in the DAT-rich striatal and SERT-rich extrastriatal brain areas (amygdala, hippocampus, thalamus, midbrain and pons). DLB/AD+ patients had significantly lower 123I-FP-CIT BRs in the left amygdala, and a trend was seen in the right hippocampus. Groups did not differ significantly in striatal 123I-FP-CIT BRs, neuropsychiatric or motor symptoms. Motor symptoms correlated negatively with striatal DAT BRs. DLB/AD+ patients may have lower SERT binding in limbic brain regions than DLB/AD- patients, possibly indicating faster neurodegeneration in mixed pathology.