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

• Published in: NeuroImage (Orlando, Fla.) Vol. 58; no. 1; pp. 286 - 292
• Main Authors: Li, Chunxia, Zhang, Xiaodong, Komery, Amelia, Li, Yingxia, Novembre, Francis J., Herndon, James G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2011; Elsevier Limited
• Subjects: Acquired immune deficiency syndrome; AIDS; AIDS Dementia Complex - pathology; AIDS Dementia Complex - psychology; Algorithms; Animal cognition; Animal models; Animals; Anisotropy; Atrophy; Behavior; Blood; Brain - pathology; Brain research; Caudate Nucleus - pathology; CD4 Lymphocyte Count; CD8-Positive T-Lymphocytes; Cerebral blood flow (CBF); Cerebrovascular Circulation - physiology; Cognition - physiology; Diffusion; Diffusion tensor imaging (DTI); Diffusion Tensor Imaging - methods; HIV; HIV/AIDS; Human immunodeficiency virus; Image Processing, Computer-Assisted; Infections; Longitudinal Studies; Lymphocyte Count; Macaca nemestrina; Magnetic Resonance Imaging - methods; Neuro-AIDS; Non-human primate; Parietal Lobe - pathology; Recognition (Psychology) - physiology; Simian Acquired Immunodeficiency Syndrome - pathology; Simian Acquired Immunodeficiency Syndrome - psychology; Simian Immunodeficiency Virus; SIV; Space Perception - physiology; Studies; Variance analysis; HIV/AIDS; SIV; Neuro-AIDS; Cerebral blood flow (CBF); Diffusion tensor imaging (DTI); Non-human primate
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2011.05.068

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 T 2- 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. ►Monkey is an ideal model of Neuro-AIDS for longitudinal MRI study. ►CBF and FA changes are significantly correlated with the blood cell depletion. ►CBF and FA are sensitive image markers of the HIV/AIDS disease.