In Vitro Blood-Brain Barrier Modeling adapted for Peripheral Blood Mononuclear Cell Transmigration from HIV-Positive Patients for Clinical Research on Therapeutic Drug Intervention.

OBJECTIVE: HIV-associated cognitive impairment (HACI) continues to persist for HIV-seropositive individuals who are on antiretroviral therapy (ART). HACI develops in part when HIV-infected monocytes (MOs) transmigrate through the blood-brain barrier (BBB) and secrete pro-inflammatory cytokines and chemokines, which leads to neuronal damage. In vitro BBB models are important tools that can elucidate mechanisms of MO transmigration. Previously described in vitro BBB models relied on pathology specimens, resulting in potentially variable and inconsistent results. This project reports on a reliable and consistent alternative in vitro BBB model that has the potential to be used in clinical research intervention studies analyzing the effects of ART on the BBB and on MO transmigration.

METHODS: A bilayer BBB model was established with commercially available astrocytes and endothelial cells on a 3μm PET membrane insert to allow the contact of astrocytic foot processes with endothelial cells. Inserts were cultured in growth medium for 7 days before exposure to HIV- or HIV+ peripheral blood mononuclear cells (PBMCs). PBMCs were allowed to transmigrate across the BBB for 24 hours.

RESULTS: Confluency and integrity measurements by trans-endothelial electrical resistance (TEER) (136.7 ± 18.3Ω/cm2) and permeability (5.64 ± 2.20%) verified the integrity of the in vitro BBB model. Transmigrated MOs and non-MOs were collected and counted (6.0x104 MOs; 1.1x105 non-MOs). Markers indicative of glial fibrillary acidic protein (GFAP), von Willebrand factor (vWF), and p-glycoprotein (Pgp) were revealed in immunofluorescence staining (IF), indicating BBB phenotype and functionality.

CONCLUSION: Potential applications for this model include assessing the HIV DNA copy numbers of transmigrated cells (pre- and post-targeted ART) and understanding the role of oxidative stress related to HIV DNA and HACI.