Intracellular Concentrations of Non-Nucleoside Reverse Transcriptase Inhibitors and its Potential Role on Apoptosis in Peripheral Blood Mononuclear Cells

Akihiko Saitoh

doi:10.4172/jaa.1000029

Abstract

Background: Efavirenz (EFV) and nevirapine (NVP) are non-nucleoside reverse transcriptase inhibitors (NNRTIs) that are frequently used in combination with other antiretrovirals for the treatment of HIV-infected persons. Little information is available regarding the intracellular concentrations (ICs) of EFV and NVP in peripheral blood mononuclear cells (PBMCs) and its potential role for cellular toxicity. Methods: PBMCs from healthy adult donors were treated with or without the mean peak steady-state levels (Cmax) of EFV (12.4µM) and NVP (17.0µM) in human plasma during antiretroviral therapy multiplied by 0.5, 1.0, 2.0 and 4.0. After 48 hr treatment, ICs of EFV and NVP were measured using liquid chromatoagraphy-ion trap/mass spectrometry. The degree of apoptotic cells and mitochondrial membrane potential in PBMCs were measured by flow cytometry. Results: The mean log ICs of x1.0 Cmax NVP in PBMCs (2.00 ± 0.23 µM) were significantly lower than the one of x1.0 Cmax EFV (2.95 ± 0.22 µM) (P < 0.01). Similar significant differences of mean log ICs were observed when the concentration of NNRTIs were x0.5 Cmax (1.62 ± 0.26 µM vs. 2.87 ± 0.13 µM, P < 0.01) and x2.0 Cmax (1.99 ± 0.39 µM vs. 3.11 ± 0.21 µM, P < 0.01). Furthermore, apoptotic PBMCs were lower than PBMC treated with the concentrations of NVP above the plasma Cmax observed clinically in patients as compared to those treated with comparable concentrations of EFV (P < 0.01). Conclusion: These in vitro data suggest that ICs of NVP in PBMCs are significantly lower than ICs of EFV in PBMC and are also associated with less apoptotic PBMCs. The clinical relevance of this observation remains to be elucidated.

Highlights

Active antiretroviral therapy (HAART) has significantly changed the morbidity and mortality associated with HIV-1 infection [1,2,3]
There are other factors contributing to these different clinical responses, recent pharmacogenetic studies suggest that at least some of these variable responses to nucleoside reverse transcriptase inhibitors (NNRTIs)-containing regimens are predictable based on variants in genes responsible for metabolizing and transporting antiretrovirals [14]
We previously reported that specific CYP2B6 genetic variants were determinants of NVP pharmacokinetics (PK) and affected the immunologic recovery of HIV-1 infected children who received NVP containing Highly active antiretroviral therapy (HAART) [15]

Summary

Introduction

Active antiretroviral therapy (HAART) has significantly changed the morbidity and mortality associated with HIV-1 infection [1,2,3]. Among NNRTIs, efavirenz (EFV) has been included in the majority of treatment guidelines as the preferred first-line regimen for HIV-infected adults [4] and children >3 years old in the United States and developed countries. We previously reported that specific CYP2B6 genetic variants were determinants of NVP pharmacokinetics (PK) and affected the immunologic recovery of HIV-1 infected children who received NVP containing HAART [15]. Children with CYP2B6 variants receiving an EFV containing HAART regimen achieved higher plasma concentrations of EFV, we failed to observe improved immunologic recovery [16]. Efavirenz (EFV) and nevirapine (NVP) are non-nucleoside reverse transcriptase inhibitors (NNRTIs) that are frequently used in combination with other antiretrovirals for the treatment of HIV-infected persons. Little information is available regarding the intracellular concentrations (ICs) of EFV and NVP in peripheral blood mononuclear cells (PBMCs) and its potential role for cellular toxicity

Methods

Results

Conclusion