Impact of HIV on Brain Structure and Function

Neurocognitive disorders are a continuing issue for people living with the human immunodeficiency virus (HIV) and despite larger use of combination antiretroviral therapy (ART), neurocognitive impairment is still common. However, the impact that an HIV infection and aging has on brain structure, functional connectivity and neuropsychological performance is still not fully understood.

Understanding these effects over the course of a lifetime is key to providing appropriate care for people living with HIV. A recent study conducted by investigators from Washington University, in collaboration with the University of Missouri, set out to understand this issue. The data was presented during the Conference on Retroviruses and Opportunistic Infections (CROI) 2021 virtual sessions.

The study included 297 virologically well-controlled people living with HIV and 1,509 people who did not have HIV. The participants were matched for age, sex, and education, with more than half being male and all having a mean age of 48.5. All of the study participants completed structural and functional neuroimaging. 

Those in the HIV arm were classified as cognitively normal (HIVCN) or impaired (HIVCI) based on a neuropsychological performance battery consisting of five domains. Relief feature selection identified the strongest predictive functional resting state networks (RSNs) with regards to HIV serostatus and degree of cognitive impairment within specific age bins (< 35, 35-55, and >55 years old).

Findings from the study showed that the strongest predictive RSNs of HIV status between HIV- controls and HIVCN as the salience (SAL) and parietal memory network (PMN). The strongest predictive RSNs of HIV status between HIV- controls and HIVCI were the SAL, PMN, and frontal parietal (FPN). The strongest predictive RSNs of HIV cognitive impairment status between HIVCN and HIVCI were the SAL, FPN, and ventral attention (VAN).

The frontal parietal became a stronger predictor with age, while salience and ventral attention lost predictive strength. The structural neuroimaging showed differences in RSN topology occurring in the cortical and subcortical regions, including the dorsal and rostral lateral prefrontal cortex anterior cingulate, and caudate.

“Our results suggest PMN and SAL are highly impacted by HIV, and additional involvement of FPN leads to increased cognitive impairment,” the authors wrote. “When evaluating different age bins, variability in RSNs predictive strength was observed, even under viral suppression. These results suggest a complex set of RSN and structural changes that are unique to HIV status, aging, cognitive impairment status, and anatomy.”