Ethinylestradiol and estradiol have different effects on oxidative stress and nitric oxide synthesis in human endothelial cell cultures

Study objective

To compare the effects of ethinylestradiol (EE) and 17β-estradiol (E₂) on nitric oxide (NO) production and protection against oxidative stress in human endothelial cell cultures.

Design

Experimental study.

Settings

Research laboratory.

Material

Human ECV304 endothelial cell cultures.

Intervention(s)

The NO synthesis was determined by flow cytometry, and oxidative stress was determined by a cell viability assay, after exposure to hydrogen peroxide (H₂O₂) and stimulation of endothelial cells with EE at concentrations similar to those of a contraceptive containing 30 μg EE.

Main Outcome Measure(s)

The effects of EE were compared with those of E₂ at concentrations similar to those occurring during the follicular phase.

Result(s)

Ethinylestradiol did not increase NO synthesis and did not protect cells against oxidative stress. The viability of the cells incubated with E₂ in combination with H₂O₂ was greater than the viability obtained with H₂O₂ only or with H₂O₂ in combination with EE. The cells stimulated with E₂ presented a significant increase in NO production compared with control.

Conclusion(s)

In contrast to the effects of E₂, EE did not protect human ECV304 endothelial cells against oxidative stress and did not increase their production of NO.

Key Words: Ethinylestradiol, nitric oxide, antioxidant, endothelial cells, cardiovascular disease