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Journal of Environmental Pathology, Toxicology and Oncology
Factor de Impacto: 1.241 Factor de Impacto de 5 años: 1.349 SJR: 0.356 SNIP: 0.613 CiteScore™: 1.61

ISSN Imprimir: 0731-8898
ISSN En Línea: 2162-6537

Journal of Environmental Pathology, Toxicology and Oncology

DOI: 10.1615/JEnvironPatholToxicolOncol.v25.i3.30
pages 585-596

Inhibition of Prostacyclin Release by Cigarette Smoke Extract in Endothelial Cells is not Related to Enhanced Superoxide Generation and NADPH-Oxidase Activation

M. Mahfouz
The H. E. Moore Heart Research Foundation, Champaign, IL, USA
Zhou Qi
Burnsides Research Laboratory, University of Illinois, Urbana, IL, USA
F. A. Kummerow
The H. E. Moore Heart Research Foundation, Champaign; and Burnsides Research Laboratory, University of Illinois, Urbana, IL, USA

SINOPSIS

Exposure of human umbilical endothelial cells (ECs) to cigarette smoke extract (CSE) activated the NADPH-oxidase enzyme and increased the production of superoxide (O2) as well as reactive oxygen species (ROS). CSE also inhibited the prostacyclin (PGI2) formation by ECs. Preincubation of ECs with diphenylene iodonium (DPI), the inhibitor of NADPH oxidase, blocked the increase of O2 production, but neither lowered the ROS level nor prevented the inhibition of PGI2 formation in CSE-treated cells. Preincubation of ECs with a medium supplemented with 1 mM vitamin C did not decrease, but rather increased the O2 production in CSE-treated cells. However, adding 1 mM glutathione (GSH) to vitamin C decreased the O2 production, indicating that vitamin C was overwhelmed by the prooxidant in CS, and GSH enhanced the recycling process and spared vitamin C. The ROS level remained high in CSE-treated cells even after preincubation with vitamin C or vitamin C + GSH compared to the control cells. These results are discussed in light of the possible decrease of antioxidant enzyme activities in CSE-treated cells and the increase of cellular hydrogen peroxide (H2O2) generated from the CSE, which cause an imbalance between oxidizing species and the antioxidants producing oxidative stress in CSE-treated cells. These results demonstrate that CSE has a direct inhibitory effect on PGI2 formation and enhances the level of ROS in CSE-treated ECs, regardless of the activation of NADPH-oxidase.