Magnetic resonance spectroscopy reveals that activated monocytes contribute to neuronal injury in SIV neuroAIDS.

Difficulties in understanding the mechanisms of HIV neuropathogenesis include the inability to study dynamic processes of infection, cumulative effects of the virus, and contributing host immune responses. We used H magnetic resonance spectroscopy and studied monocyte activation and progression of CNS neuronal injury in a CD8 lymphocyte depletion model of neuroAIDS in SIV-infected rhesus macaque monkeys. We found early, consistent neuronal injury coincident with viremia and SIV infection/activation of monocyte subsets and sought to define the role of plasma virus and monocytes in contributing to CNS disease.

Relationships between astrogliosis and 1H MR spectroscopic measures of brain choline/creatine and myo-inositol/creatine in a primate model.

Background And Purpose: In vivo 1H MR spectroscopy demonstrates elevated choline (Cho)/creatine (Cr) and myo-inositol (MI)/Cr in many neurologic diseases that has been ascribed to gliosis. We tested the hypotheses that in vivo Cho/Cr and/or MI/Cr levels are correlated with glial fibrillary acidic protein (GFAP) immunostains and that the changes are water-soluble metabolites.

Methods: We performed postmortem 1H MR spectroscopy and GFAP immunohistochemistry in brains from seven rhesus macaques acutely infected with simian immunodeficiency virus (SIV) and in four controls and compared the findings with previous in vivo MR spectroscopic results.

Quantitative neuropathologic correlates of changes in ratio of N-acetylaspartate to creatine in macaque brain.

Purpose: To elucidate the neuropathologic basis of transient changes in the ratio of N-acetylaspartate (NAA) to creatine (Cr) in the primate brain by using a simian immunodeficiency virus (SIV)-infected macaque model of the neurologic manifestation of acquired immune deficiency syndrome.

Materials And Methods: This study was approved by the Massachusetts General Hospital Subcommittee on Research and Animal Care and the Institutional Animal Care and Use Committee of Harvard University. Rhesus macaques infected with SIV were evaluated during the 1st month of infection.

Comparisons of brain metabolites observed by HRMAS 1H NMR of intact tissue and solution 1H NMR of tissue extracts in SIV-infected macaques.

The objective of this study was to compare ex vivo proton high-resolution magic angle spinning magnetic resonance spectra of intact tissue with those spectra obtained by solution (1)H NMR of brain extracts of the same sample. Sixteen brain tissue samples from simian immunodeficiency virus-infected rhesus macaques from both frontal cortex and putamen were evaluated by comparing brain metabolite quantities of N-acetylaspartate (NAA), choline-containing compounds (Cho), myo-inositol (MI), creatine (Cr), lactate (Lac), glutamate (Glu) and acetate (Ace). The ratios of the individual NMR peak areas of all metabolites relative to the creatine peak area were calculated.

A prospective longitudinal in vivo 1H MR spectroscopy study of the SIV/macaque model of neuroAIDS.

Background: The neurological complications of HIV infection remain poorly understood. Clinically, in vivo 1H magnetic resonance spectroscopy (MRS) demonstrates brain injury caused by HIV infection even when the MRI is normal. Our goal was to undertsand the dynamics of cerebral injury by performing a longitudinal in vivo 1H MRS study of the SIV/macaque model of neuroAIDS.