Protein binding in patients with late-life depression

Abstract

Context: Depression has been identified as a risk factor and a prodrome of dementia. Common neurobiological mechanisms may underlie this clinical and phenomenologic overlap. Objective:Toexamineandcompareprotein (amyloidand tau) binding in critical brain regions in patients diagnosed as having late-life major depressive disorder (MDD) and healthycontrolindividualsusing2-(1-{6-[(2- [ 18F]fluoroethyl) (methyl)-amino]-2-naphthyl}ethylidene) malononitrile ([ 18F]FDDNP) positron emission tomography. Design: A cross-section neuroimaging study using positron emission tomography. Setting: University of California, Los Angeles. Patients: Our samples comprised 20 patients diagnosed as having MDD and 19 healthy control individuals of comparable age, sex, and educational level. Main Outcome Measure: Relative distribution volume in regions of interest was used as the measure of [ 18F]FDDNP binding in all study participants. Results: When compared with controls, [ 18F]FDDNP binding was significantly higher overall and in the posterior cingulate and lateral temporal regions in the MDD group. Conclusions: These findings suggest that neuronal injury associated with higher protein load in critical brain regions might provide a mechanism in the pathophysiologic manifestation of MDD in late life and have implications for the therapeutics of depression in elderly individuals. ©2011 American Medical Association. All rights reserved.