Reduction in cerebral oxygen metabolism in subcortical regions may be a biomarker of cognitive decline in people living with human immunodeficiency virus.

Abstract

Regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2 ) in whole brain, white matter, gray matter and lenticular nuclei were studied in people living with human immunodeficiency virus (PLHIV) as well as HIV-associated neurocognitive disorder (HAND). Treatment-naïve PLHIV underwent neurocognitive assessment and magnetic resonance (MR) measurement of rCBF and rCMRO2 with repeat after 12months of antiretroviral therapy (ART). Age- and sex-matched controls underwent single MR measurements. Regional CBF and rCMRO2 were compared amongst symptomatic, asymptomatic, normal HAND and controls using analysis of variance. Longitudinal analysis of HAND worsening (≥1 category) was assessed after 12 months of ART and correlated with rCBF and rCMRO2 measured by MR imaging using the paired-sample t test. Thirty PLHIV completed baseline and 12-month assessments (29 with rCMRO2 measurement). At baseline HAND assessment, 13% had no cognitive impairment, 27% had asymptomatic neurocognitive impairment, 60% had mild neurocognitive disorder and none had HIV-associated dementia. At 12months, 13% had no cognitive impairment, 20% had asymptomatic neurocognitive impairment, 50% had mild neurocognitive disorder and 17% had HIV-associated dementia. 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). In recently diagnosed PLHIV, no association was found between rCBF or rCMRO2 and cognitive impairment at baseline. There was a reduction in rCMRO2 in those with worsening of cognitive function at 12months on ART. Reduction in rCMRO2 may be a biomarker of cognitive decline in PLHIV.