White matter microstructure among perinatally HIV-infected youth: a diffusion tensor imaging study

Area of Science:

• Neuroimaging
• Infectious Diseases
• Pediatric Neurology

Background:

• Perinatally HIV-infected (PHIV) youths on combination antiretroviral therapy (cART) may experience long-term neurological effects.
• White matter microstructure integrity is crucial for cognitive function and can be affected by chronic conditions and treatments.
• Diffusion Tensor Imaging (DTI) metrics offer insights into white matter changes.

Purpose of the Study:

• To evaluate white matter microstructure integrity in PHIV youths on cART compared to healthy controls (HC) using DTI metrics.
• To identify specific DTI alterations and their regional distribution in the brains of PHIV youths.
• To explore potential contributing factors for observed DTI changes.

Main Methods:

• Utilized 3T MRI scanner to acquire DTI data from 14 PHIV youths (mean age 17.9 years) on cART and 17 HC (mean age 18.0 years).
• Analyzed four DTI metrics: fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD).
• Employed voxel-based analysis of covariance (ANCOVA) with age and gender as covariates, followed by region-of-interest analyses.

Main Results:

• Observed regional increases in FA in PHIV youths in areas including the left middle frontal gyrus and right precuneus.
• Identified increased MD in the right precentral gyrus and decreased MD in the white matter of the right superior parietal lobule and right inferior temporal gyrus/fusiform gyrus.
• Found overlapping regions of increased/decreased radial diffusivity (RD) with mean diffusivity (MD) changes, and both increased and decreased axial diffusivity (AD) in several regions.

Conclusions:

• Findings reveal distinct white matter microstructure alterations in PHIV youths on cART, including previously unreported increases in FA.
• Observed DTI metric changes suggest potential contributions from both antiretroviral therapy toxicity and persistent HIV infection.
• Early and prolonged cART in this cohort may influence white matter integrity, necessitating further investigation into causative factors.