Estrogen does not prevent endothelial dysfunction caused by cigarette smoking

Area of Science:

• Cardiovascular Physiology
• Endocrinology
• Reproductive Health

Background:

• Estrogen generally supports endothelial function.
• Acute tobacco use is known to cause endothelial dysfunction.
• The impact of smoking on endothelial function across the menstrual cycle remains understudied.

Purpose of the Study:

• To investigate if estrogen's protective effects on endothelial function are altered by smoking during different menstrual cycle phases.
• To determine the immediate and short-term effects of smoking one cigarette on brachial artery endothelial function in relation to estradiol levels.

Main Methods:

• Noninvasive measurement of brachial artery endothelium-dependent dilation.
• Assessment before, 10 minutes, and 1 hour after smoking one cigarette.
• Studies conducted in 17 healthy premenopausal women during early (Days 1-3) and mid-cycle (Days 9-13) phases, with estradiol measurements.

Main Results:

• Higher estradiol levels in the mid-cycle phase correlated with significantly greater baseline endothelial-dependent dilation compared to the early phase.
• Smoking one cigarette caused a comparable, marked depression in endothelial function in both early and mid-cycle phases.
• Endothelial function fully recovered within one hour after smoking in both menstrual cycle stages.

Conclusions:

• Acute cigarette smoking negates the protective influence of circulating estrogen on endothelial function.
• The detrimental effect of smoking on endothelial function is consistent across different levels of estrogen during the menstrual cycle.