Imaging correlates of the blood-brain barrier disruption in HIV-associated neurocognitive disorder and therapeutic implications.

Objective: HIV-associated neurocognitive disorders (HANDs) in the context of suppressive combination antiretroviral therapy (cART) still occur. We explored the role of blood-brain barrier (BBB) disruption in the pathogenesis of HAND in the context of fully suppressive cART using dynamic contrast enhanced perfusion (DCE-P) MRI. DCE-P is a new MRI technique that measures capillary permeability as an indicator for BBB integrity. We hypothesized that virally suppressed incident HAND would be associated with an impaired BBB as determined by DCE-P.

Design: A cross sectional study.

Methods: K-trans, a metric derivative of DCE-P, was obtained from different regions of the brain in a cohort of 20 patients with HAND who were virally suppressed in both cerebrospinal fluid (CSF) and blood compared with CSF and blood markers of neuroinflammation as well as with neurometabolites derived from magnetic resonance (MR) spectroscopy.

Results: The K-trans data showed significantly impaired BBB in HAND patients when compared with the controls in the regions of the basal ganglia and anterior frontal white matter (both P < 0.0001). CSF neopterin and CSF/serum albumin ratio correlated positively with K-trans but not with blood levels.

Conclusion: This study indicates that HAND in the context of viral suppression is associated with BBB disruption and the DCE MR derived K-trans metric is a very sensitive parameter to identify the BBB disruption. The finding of region-specific BBB disruption rather than globally and the lack of correlation with blood markers of neuroinflammation suggest that HIV and not systemic inflammation is driving the BBB disturbance and that the BBB disruption is a consequence of HIV already in the brain as opposed to HIV first causing BBB disruption then brain disease.