Research article

In vivo proton magnetic resonance spectroscopy reveals region specific metabolic responses to SIV infection in the macaque brain

Eva-Maria Ratai^1,2 , Sarah J Pilkenton^1,2 , Jane B Greco^1,2 , Margaret R Lentz^1,2 , Jeffrey P Bombardier¹ , Katherine W Turk¹ , Julian He^1,2 , Chan-Gyu Joo^1,2 , Vallent Lee¹ , Susan Westmoreland^2,3 , Elkan Halpern^2,4 , Andrew A Lackner⁵ and R Gilberto González^1,2

¹  Neuroradiology Division, Department of Radiology and A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129, USA

²  Harvard Medical School, Boston, Massachusetts, 02115, USA

³  New England Primate Research Center, Southborough, Massachusetts, 01772, USA

⁴  Institute for Technology Assessment, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, 02129, USA

⁵  Tulane National Primate Research Center, Tulane University Health Science Center, Covington, Louisiana, 70433, USA

author email corresponding author email

BMC Neuroscience 2009, 10:63doi:10.1186/1471-2202-10-63

Published:	22 June 2009

Abstract

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.