Postmortem Analysis of Dolutegravir, Tenofovir, Lamivudine, and Efavirenz Penetration in Multiple Central Nervous System Compartments

Abstract

Background: Central nervous system (CNS) compartmentalization provides opportunity for human immunodeficiency virus (HIV) persistence and resistance development. Differences between cerebrospinal fluid (CSF) and cerebral matter regarding HIV persistence are well described. However, CSF is often used as surrogate for CNS drug exposure, and knowledge from solid brain tissue is rare.

Methods: Dolutegravir, tenofovir, lamivudine, and efavirenz concentrations were measured across 13 CNS regions plus plasma in samples collected during autopsy in 49 Ugandan decedents. Median time from death to autopsy was 8 hours (interquartile range, 5-15 hours). To evaluate postmortem redistribution, a time course study was performed in a mouse model.

Results: Regions with the highest penetration ratios were choroid plexus/arachnoid (dolutegravir and tenofovir), CSF (lamivudine), and cervical spinal cord/meninges (efavirenz); the lowest were corpus callosum (dolutegravir and tenofovir), frontal lobe (lamivudine), and parietal lobe (efavirenz). On average, brain concentrations were 84%, 87%, and 76% of CSF for dolutegravir, tenofovir, and lamivudine, respectively. Postmortem redistribution was observed in the mouse model, with tenofovir and lamivudine concentration increased by 350% and efavirenz concentration decreased by 24% at 24 hours postmortem.

Conclusions: Analysis of postmortem tissue provides a unique opportunity to investigate CNS antiretroviral penetration. Regional differences were observed paving the way to identify mechanisms of viral compartmentalization and/or neurotoxicity.

Keywords: HIV; antiretroviral; central nervous system; penetration; postmortem analysis.

Figure 1.

Antiretroviral concentrations across brain regions. Boxplots of concentrations of dolutegravir, tenofovir, lamivudine, and efavirenz in plasma and brain regions. The lower and upper hinges of the box correspond to the first and third quartiles (the 25th and 75th percentiles). The upper whisker extends from the hinge to the largest value no further than 1.5 * IQR from the hinge. The lower whisker extends from the hinge to the smallest value at most 1.5 * IQR of the hinge. Boxes of solid brain tissues are ranked by medians from greatest to smallest (except for CSF and composite brain). Red dashed lines in the box plots of the brain concentration represent the lower and upper boundary of in vitro EC₅₀ (dolutegravir, 0.008–0.90 ng/mL; tenofovir, 11.5–2439.5 ng/mL; lamivudine, 0.69–3450 ng/mL) or EC_90–95 (efavirenz 0.537–7.9 ng/mL). The asterisks indicate significant results from the pairwise paired t tests: *P < .05, **P < .01, ***P < .001. To optimize space, the significances are arranged to show the least number of contrast lines, and the arrows are pointing at the smaller region in the contrast pairs. Abbreviations: CSF, cerebrospinal fluid; EC₅₀, 50% maximum effective concentration; EC_90–95, 90%–95% maximum effective concentration.

Figure 2.

Concentrations of tenofovir, lamivudine, and efavirenz in mice brain over time postmortem. Numbers (folds) above the concentrations are ratios between median concentration at a certain postmortem time and median concentration at time of death (0 hour), in replicates of 6 mice at each time point. The upper and lower error bars correspond to + and - standard error.