Objective:

To determine whether cognitive impairment and brain injury as measured by proton magnetic resonance spectroscopy (MRS) persist in the setting of HAART.

Design:

This study is an observational cohort study.

Methods:

MRS was performed in 268 patients: HIV-negative controls (N= 28), HIV-positive neuroasymptomatic individuals (N= 124), and individuals with AIDS dementia complex (ADC; N= 50) on stable antiretroviral therapy (ART) with a mean duration of infection of 12 years and CD4 cell count of 309 cells/μl. Four metabolites were measured over creatine: N-acetyl aspartate (NAA), marker of neuronal integrity; choline (Cho), myoinositol, markers of inflammation, and glutamate and glutamine (Glx) in the basal ganglia, frontal white matter (FWM), and mid-frontal cortex. Analyses included analysis of variance, analysis of covariance, linear, and nonparametric regression models.

Results:

Cognitive impairment was found in 48% of HIV-infected individuals. Both HIV-positive groups showed significant increases in myoinositol/creatine or Cho/creatine in all brain regions when compared to controls; a significant decrease in Glx/creatine in the FWM was observed in the neuroasymptomatic group; and only individuals with ADC showed a significant reduction in NAA/creatine, although a significant trend for decreasing NAA/creatine in the basal ganglia was found across the groups. Effects related to aging and duration of infection, but not central nervous system penetration effectiveness were observed.

Conclusion:

Brain inflammatory changes remain ubiquitous among HIV-infected individuals, whereas neuronal injury occurs predominantly in those with cognitive impairment. Together these findings indicate that despite the widespread use of HAART, HIV-associated cognitive impairment and brain injury persist in the setting of chronic and stable disease.

Background

HIV infection is well known to cause neurological damage resulting in cognitive and behavioral impairments that constitute the AIDS dementia complex (ADC), also referred to as HIV-associated neurocognitive disorder (HAND)[1–3]. The introduction of HAART or combined antiretroviral therapy (cART) has resulted in marked improvement in survival with a substantial increase in the number of asymptomatic infected patients with improved immunological status [3, 4]. Despite the reported systemic and cognitive benefits, the effects of HAART on neurological function have remained uncertain, and specifically, whether HIV-infected patients who are otherwise asymptomatic can develop brain pathology and cognitive impairment in the setting of chronic and stable disease [5–8]. Preliminary data suggest that HIV may continue to affect the brain even in the presence of HAART [9–14]. Coupled with increased survival and an aging patient population, the potential persistence of brain injury associated with HIV infection could result in an increase in the prevalence of impairment in the chronically infected and treated population.