Oxidative stress impairs endothelial function in nondipper hypertensive patients

Area of Science:

• Cardiovascular Medicine
• Hypertension Research
• Endothelial Function Studies

Background:

• Essential hypertension and cardiovascular risk factors are associated with endothelial dysfunction.
• Nondipper circadian blood pressure patterns in hypertensive patients correlate with increased cerebrovascular and cardiovascular complication risks compared to dipper patterns.

Purpose of the Study:

• To investigate the association between the nondipper blood pressure pattern and endothelial function in essential hypertension patients.

Main Methods:

• Forearm blood flow (FBF) response to acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed in 190 hypertensive patients.
• Patients were stratified into dipper and nondipper groups based on ambulatory blood pressure monitoring.
• The impact of oxidative stress on FBF was evaluated using vitamin C coinfusion.

Main Results:

• Nondipper hypertensive patients showed significantly lower FBF response to acetylcholine compared to dippers (228% vs. 473%).
• FBF responses to sodium nitroprusside were comparable between dipper and nondipper groups, indicating preserved endothelium-independent vasodilation.
• Vitamin C administration improved acetylcholine-stimulated FBF in nondippers, suggesting a role for oxidative stress.

Conclusions:

• Endothelium-dependent vasodilation is impaired in nondipper hypertensive patients.
• Oxidative stress likely contributes to endothelial dysfunction observed in nondipper hypertension.