Mapping white matter integrity in elderly people with HIV

Abstract

People with HIV are living longer as combination antiretroviral therapy (cART) becomes more widely available. However, even when plasma viral load is reduced to untraceable levels, chronic HIV infection is associated with neurological deficits and brain atrophy beyond that of normal aging. HIV is often marked by cortical and subcortical atrophy, but the integrity of the brain’s white matter (WM) pathways also progressively declines. Few studies focus on older cohorts where normal aging may be compounded with HIV infection to influence deficit patterns. In this relatively large diffusion tensor imaging (DTI) study, we investigated abnormalities in WM fiber integrity in 56 HIV+ adults with access to cART (mean age: 63.9 ± 3.7 years), compared to 31 matched healthy controls (65.4 ± 2.2 years). Statistical 3D maps revealed the independent effects of HIV diagnosis and age on fractional anisotropy (FA) and diffusivity, but we did not find any evidence for an age by diagnosis interaction in our current sample. Compared to healthy controls, HIV patients showed pervasive FA decreases and diffusivity increases throughout WM. We also assessed neuropsychological (NP) summary z-score associations. In both patients and controls, fiber integrity measures were associated with NP summary scores. The greatest differences were detected in the corpus callosum and in the projection fibers of the corona radiata. These deficits are consistent with published NP deficits and cortical atrophy patterns in elderly people with HIV.

White matter damage and effects of nadir CD4+ count on patients with asymptomatic HIV associated dementia complex–A DTI study

“…2) The frontal lobe white matter and CSO may be subject to early injury in patients infected with HIV, and this agrees with previous HIV studies [3,5,10,22,24,25]. Smith AB et al [25] reported that there is a frontal lobe white matter predominant involvement in HIV infection of the brain.…”

“…Otherwise, Stubbe-Drger B et al [3,5,10] suggested that FA could be more sensitive than other MRI approaches to microstructural white matter abnormalities. This may be due to the differences in patients receiving HAART or not, in our study, all patients were not receiving any antiretroviral treatment, their participants were on a stable antiretroviral regimen for at least 12 consecutive weeks prior to study, based on this inconsistency, we will continue to study the effects of HAART on white matter DTI parameters of HIV patients.…”

White Matter Development is Potentially Influenced in Adolescents with Vertically Transmitted HIV Infections: A Tract-Based Spatial Statistics Study

“…The findings that FA values within the genu, body, and splenium of the corpus callosum were reduced in HIV-positive adolescents are consistent with findings in previous studies on HIV-infected children and adults. For example, FA values for the genu, 10 body, 21 and splenium 8 of the corpus callosum 11,22 are significantly reduced in HIV-infected adults. Decreased FA of the body of corpus callosum is also reported in HIV-infected children.…”

“…25 Moreover, deceased FA is also found in the anterior and superior corona radiata in HIV-infected participants. 10,11 The anterior corona radiata is associated with functions of the executive network. 26 Previous studies have focused on HIV-infected children and found that the subjects displayed visual-spatial memory and motor developmental deficits and executive function disorders.…”

“…6 Recent DTI studies have identified abnormalities in the subcortical WM and corpus callosum, despite appearing normal on conventional MRI in HIV-infected adults. 7 Abnormal WM integrity, such as reduced fractional anisotropy (FA) or increased mean diffusivity (MD), was found in the splenium, 8 superior longitudinal fasciculus, 9 anterior and superior corona radiata, 10,11 and frontal and parietal WM 12 in HIVinfected adults. Similarly, neuroimaging studies have also demonstrated vast WM abnormalities in adolescents with vertically transmitted HIV infection.…”