Category: Preclinical Development
Purpose: Globally, HIV-AIDS remains a major health concern. Around 36.7 million people were living with HIV-AIDS in 2016. The advent of highly active & combination antiretroviral therapy has substantially increased the life expectancy of patients infected with HIV. However, this has brought into sharp contrast the incidence of several 'Non-AIDS' diseases such as Neuro AIDS. Given the patients depleted immune condition, the use and abuse of drugs & addictive substances such as tobacco smoking can further deteriorate their overall health and accelerate the progression and severity of the disease. The rate of tobacco smoking is exceedingly high in HIV infected individuals (40-75%) when compared with the general population (15%). Furthermore, 50% of the HIV infected population exhibits neurological complications including NeuroAIDS. We hypothesize that the oxidative stress caused by tobacco smoking and HIV-1 envelope protein gp120 may have a contributory effect on the increasing burden of NeuroAIDS related morbidity and mortality in HIV infected individuals who smoke.
Methods: To study the effects of co-exposure of Tobacco Smoke Extract and HIV-1 gp120 on Primary Human Brain Microvascular Endothelial Cells (HBMECs) by measuring Oxidative Stress and subsequent Antioxidant response, HBMECs were treated individually with HIV-1 gp120 and Tobacco Smoke extract. Gp120 dose for in vitro studies was selected based on a MTT cell viability study. We assessed barrier function by measuring transendothelial electrical resistance (TEER) and permeability. Total proteins were isolated from each treatment group and examined for tight junction proteins (Occludin, ZO-1) expression. Generation of ROS was detected by DCFDA assay. Immunocytochemistry was performed to further confirm the oxidative damage with the expression of Nrf2.
Results: Co-exposure of Tobacco Smoke Extract and HIV-1 gp120 on HBMECs showed decrease in - Cell Viability, Blood Brain Barrier Integrity and Antioxidant response and increase in oxidative stress. Co-exposure negatively impacted BBB integrity as expected. Decrease in TEER measurements and the parallel increase in permeability to FITC confirmed our hypothesis. ZO-1 and Occludin expression levels were reduced in a co-exposed group. Activation of the Nrf2 with its reduced expression in a group with co-exposed treatment indicated oxidative damage.
Conclusion: Co-exposure to tobacco smoke extract (TSE) and HIV-1 gp120 (gp120) further aggravated the
BBB endothelium dysfunction thereby worsening cerebrovascular condition.