Reduction in Cerebral Oxygen Metabolism in Subcortical Regions may be a Biomarker of Cognitive Decline in People Living with HIV.

OBJECTIVE We studied regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) in whole brain, white matter, gray matter, and lenticular nuclei in people living with human immunodeficiency virus (PLHIV) as well as HIV associated neurocognitive disorder (HAND). METHODS Treatment-naive PLHIV underwent neurocognitive assessment and magnetic resonance (MR) measurement of rCBF and rCMRO2 with repeat after 12 months of anti-retroviral therapy (ART). Age-sex-matched controls underwent single MR measurements. We compared rCBF and rCMRO2 amongst symptomatic, asymptomatic, normal HAND and controls using Analysis of Variance (ANOVA). Longitudinal analysis HAND worsening (≥1 category) was assessed after 12-months of ART and correlated with rCBF andrCMRO2 measured by MRI using paired-sample t-test. RESULTS Thirty PLHIV completed baseline and 12-month assessments (29 with rCMRO2 measurement). At baseline HAND assessment, 13% had no cognitive impairment (NO), 27% had Asymptomatic Neurocognitive Impairment (ANI), 60% had Mild Neurocognitive Disorder (MND), and none had HIV-associated dementia (HAD). At 12 months, 13% had NO, 20% had ANI, 50% had MND, and 17% had HAD). . In those without HAND worsening (N=21) rCMRO2 remained stable and in those with HAND worsening (N=8) rCMRO2 measurement declined from baseline to 12-months in white matter (2.05±0.40 to 1.73±0.51, p=0.03) and lenticular nuclei (4.32±0.39 to 4.00±0.51, p=0.05). CONCLUSIONS In recently diagnosed PLHIV, we found no association between rCBF or rCMRO2 and cognitive impairment at baseline. There was a reduction in rCMRO2 in those with worsening of cognitive function at 12 months on ART. Reduction in rCMRO2 may be a biomarker of cognitive decline in PLHIV.