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Joo, Chan-Gyu

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Joo

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Chan-Gyu

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Joo, Chan-Gyu
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    Proton Magnetic Resonance Spectroscopy Reveals Neuroprotection by Oral Minocycline in a Nonhuman Primate Model of Accelerated NeuroAIDS
    (Public Library of Science, 2010) Bombardier, Jeffrey P.; Annamalai, Lakshmanan; Burdo, Tricia H.; Fell, Robert; Hakimelahi, Reza; He, Julian; Autissier, Patrick; Masliah, Eliezer; Williams, Kenneth C.; González, R. Gilberto; Ratai, Eva-Maria; Joo, Chan-Gyu; Campbell, Jennifer; Lentz, Margaret R.; Halpern, Elkan F.; Westmoreland, Susan V.
    Background: Despite the advent of highly active anti-retroviral therapy (HAART), HIV-associated neurocognitive disorders continue to be a significant problem. In efforts to understand and alleviate neurocognitive deficits associated with HIV, we used an accelerated simian immunodeficiency virus (SIV) macaque model of NeuroAIDS to test whether minocycline is neuroprotective against lentiviral-induced neuronal injury. Methodology/Principal Findings: Eleven rhesus macaques were infected with SIV, depleted of CD8+ lymphocytes, and studied until eight weeks post inoculation (wpi). Seven animals received daily minocycline orally beginning at 4 wpi. Neuronal integrity was monitored in vivo by proton magnetic resonance spectroscopy and post-mortem by immunohistochemistry for synaptophysin (SYN), microtubule-associated protein 2 (MAP2), and neuronal counts. Astrogliosis and microglial activation were quantified by measuring glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (IBA-1), respectively. SIV infection followed by CD8+ cell depletion induced a progressive decline in neuronal integrity evidenced by declining N-acetylaspartate/creatine (NAA/Cr), which was arrested with minocycline treatment. The recovery of this ratio was due to increases in NAA, indicating neuronal recovery, and decreases in Cr, likely reflecting downregulation of glial cell activation. SYN, MAP2, and neuronal counts were found to be higher in minocycline-treated animals compared to untreated animals while GFAP and IBA-1 expression were decreased compared to controls. CSF and plasma viral loads were lower in MN-treated animals. Conclusions/Significance: In conclusion, oral minocycline alleviates neuronal damage induced by the AIDS virus.
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    In Vivo Proton Magnetic Resonance Spectroscopy Reveals Region Specific Metabolic Responses to SIV Infection in the Macaque Brain
    (BioMed Central, 2009) Pilkenton, Sarah J; Greco, Jane B; Bombardier, Jeffrey P; Turk, Katherine W; He, Julian; Lee, Vallent; Lackner, Andrew A; González, R Gilberto; Ratai, Eva-Maria; Lentz, Margaret R.; Joo, Chan-Gyu; Westmoreland, Susan V.; Halpern, Elkan F.
    Background: In vivo proton magnetic resonance spectroscopy (1H-MRS) studies of HIV-infected humans have demonstrated significant metabolic abnormalities that vary by brain region, but the causes are poorly understood. Metabolic changes in the frontal cortex, basal ganglia and white matter in 18 SIV-infected macaques were investigated using MRS during the first month of infection. Results: Changes in the N-acetylaspartate (NAA), choline (Cho), myo-inositol (MI), creatine (Cr) and glutamine/glutamate (Glx) resonances were quantified both in absolute terms and relative to the creatine resonance. Most abnormalities were observed at the time of peak viremia, 2 weeks post infection (wpi). At that time point, significant decreases in NAA and NAA/Cr, reflecting neuronal injury, were observed only in the frontal cortex. Cr was significantly elevated only in the white matter. Changes in Cho and Cho/Cr were similar across the brain regions, increasing at 2 wpi, and falling below baseline levels at 4 wpi. MI and MI/Cr levels were increased across all brain regions. Conclusion: These data best support the hypothesis that different brain regions have variable intrinsic vulnerabilities to neuronal injury caused by the AIDS virus.