Longitudinal diffusion tensor imaging and perfusion MRI investigation in a macaque model of neuro-AIDS: A preliminary study

• Type of Material: Article
• Authors: Chunxia Li, Emory University; Xiaodong Zhang, Emory University; Amelia Komery, Emory University; Yingxia Li, Emory University; Francis J Novembre, Emory University; James G Herndon Jr., Emory University
• Language: English
• Date: 2011-09-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2011 Elsevier Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016%2Fj.neuroimage.2011.05.068
• Title of Journal or Parent Work: NeuroImage
• ISSN: 1053-8119
• Volume: 58
• Issue: 1
• Start Page: 286
• End Page: 292
• Grant/Funding Information: The project was supported in part by the base grant from the NIH/NCRR (P51 RR000165) and NIH grant MH067769 (to FJN).
• Keywords: Neuro-AIDS; diffusion tensor imaging (DTI); Cerebral blood flow (CBF); non-human primate; SIV; HIV/AIDS
• Research Categories: Biology, Neuroscience

Abstract

The Simian immunodeficiency virus (SIV) infected macaque model exhibits neuropathological symptoms similar to those of HIV+ patients, and is ideal for studying cognitive impairment and neuropathological sequelae of disease in repeated measurements. The aim of this study is to use Diffusion Tensor Imaging (DTI) and perfusion MRI to longitudinally access the disease development in SIV-infected monkeys under controlled conditions and to cross-validate our finding with MRI studies in HIV+ patients. Three adult male pig-tailed macaques (Macaca Nemestrina) were inoculated with the SIVsmmFGb virus. Blood was collected for enumeration of CD4+ and CD8+ T cells. Serial time-sensitive high-resolution T2- weighted structural images, Cerebral Blood Flow (CBF) maps measured with the Continuous Arterial Spin Labeling (CASL) technique, and DTI images were obtained. Animals were sacrificed after 24 weeks. Cognitive behavioral tests were also carried out at each time point. Longitudinal changes in brain volume, CBF, and DTI in selected regions were analyzed statistically. In this study, CD4+ T cell counts were found declined significantly after SIV infection in all macaques. No significant neurological behavior and brain volume changes were observed following virus inoculation. The CBF was found reduced in the caudate, inferior parietal cortex, and the prefrontal cortex. Fractional Anisotropy (FA) values in the whole brain and several Regions of Interest (ROIs) decreased significantly. These longitudinal changes in CBF and FA are correlated with CD4+ T cell depletion and/or CD4:CD8 ratio. The MRI findings from this pilot study agree with previous results in HIV+ patients.