DD angiotensin-converting enzyme gene polymorphism is associated with endothelial dysfunction in normal humans

Area of Science:

• Cardiovascular Genetics
• Endothelial Function Research
• Molecular Cardiology

Background:

• A polymorphism in the angiotensin-converting enzyme (ACE) gene is implicated in myocardial infarction risk.
• The underlying mechanisms, potentially involving nitric oxide (NO) pathways, remain unclear.

Purpose of the Study:

• To investigate differences in endothelial function among individuals with varying ACE genotypes.
• To assess the impact of ACE genotype on nitric oxide-mediated and non-mediated vasodilation and vasoconstriction.

Main Methods:

• Cross-sectional study comparing endothelial function in II, ID, and DD ACE genotypes.
• Assessed forearm blood flow responses to acetylcholine (endothelial-dependent), sodium nitroprusside, and verapamil (endothelial-independent vasodilators).
• Evaluated responses to vasoconstrictors NG-monomethyl-L-arginine and norepinephrine; analyzed smoking effects within genotypes.

Main Results:

• The DD ACE genotype showed significantly blunted endothelial-dependent vasodilation (acetylcholine response).
• A significant difference was observed in endothelial-independent vasodilation (sodium nitroprusside), with DD genotype showing reduced response.
• No significant effect of ACE genotype on vasoconstrictor responses was found. Smoking exacerbated acetylcholine responses in II and DD genotypes.

Conclusions:

• The DD ACE genotype is associated with impaired stimulated endothelial NO and donated NO responses in young individuals.
• Endothelial dysfunction related to the DD ACE genotype is specific to NO-mediated pathways, not affecting non-NO vasodilators or vasoconstrictors.
• These findings highlight a genotype-specific endothelial dysfunction linked to the ACE gene, potentially contributing to cardiovascular risk.