Vascular Endothelial Toxicity Induced by HIV Protease Inhibitor: Evidence of Oxidant-Related Dysfunction and Apoptosis

Abstract

HIV-protease inhibitor (HIV-PI) drugs are critical for highly active antiretroviral therapy (HAART) efficacy, but several recent reports have suggested that metabolic and/or cardiovascular toxicities are associated with these drugs. Given the importance of the HIV-PI drug class and the widespread and chronic use of these agents in an expanding patient population, further understanding of this potential drug toxicity is imperative. Here, we investigated a role for direct endothelial toxicity induced by saquinavir (SAQ), the first HIV-PI drug marketed in the United States and still an important component of HAART therapies. In initial studies using isolated vascular tissues, we observed selective impairment of endothelium-dependent vasodilation with no effect on contractile responses. Subsequent studies using human endothelial cells in culture at clinically relevant concentrations (5 and 10 microM, 2-48 h) demonstrated concentration-dependent increases in cell death, mainly via apoptosis rather than necrosis (determined via Annexin-V positive membrane labeling). Live cell imaging also demonstrated increased intracellular oxidant production (as measured by DCF fluorescence), which could be abrogated by incubation with the antioxidant N-acetylcysteine (NAC). NAC also prevented SAQ- induced apoptotic cell death. These data demonstrate that SAQ has direct toxicological effects on endothelial cells, and that the toxicity apparently involves apoptotic pathway activation via reactive oxygen and/or nitrogen species.

State of the Science Conference

“…The potential mechanisms by which specific PI-based regimens can adversely affect endothelial function, include reduction in nitric oxide production or release, increases in reactive oxygen species (41,42), impairment of cholesterol efflux from foam cells and increased macrophage cholesterol ester accumulation through upregulation of CD36 scavenge receptor (43,44). Specific NRTI's, including stavudine and zidovudine may also increase superoxide production in experimental models (45).…”

The Spectrum of Atherosclerotic Coronary Artery Disease in HIV Patients

“…This dysfunction appears to be mediated by reduced nitric oxide production or release [41,42]. Specific mechanisms include reduced expression of endothelial nitric oxide synthase [41] and increased reactive oxygen species [42], which may be ameliorated by certain antioxidants [41][42][43]. These include impaired cholesterol efflux from foam cells and increased macrophage cholesterol ester accumulation through upregulation of the CD36 scavenger receptor [42, 43, 44••].…”

Direkte und indirekte atherogene Effekte der HIV-Infektion und antiretroviralen Therapie

“…Für Saquinavir zeigte eine Studie an humanen Endothelzellen einen von klinisch relevanten Konzentrationen von 5 und 10 μM abhängigen Anstieg der Apoptose-und Nekroseraten [27]. Ferner ließ sich auch hier eine verstärkte Bildung intrazellulärer reaktiver Oxidanzien nachweisen, die evtl.…”