Systemic hypertension augments, whereas insulin-dependent diabetes down-regulates, endothelin A receptor expression in the mammary artery in coronary artery disease patients

• BACKGROUND: Endothelin (ET) A receptor antagonism causes decreased vasodilation in hypertensive coronary arteries and decreased effects on coronary artery compliance in diabetic patients. METHODS: We investigate the mRNA expression of ET-1, ET(A) and ET(B) receptors, using real time RT-PCR, in biopsies from the internal mammary artery obtained from 49 patients, 18 diabetics and 34 hypertensives, all undergoing coronary artery bypass grafting. RESULTS: Hypertensive patients had higher ET-1 mRNA expression (16438 [8417, 23917]), than normotensive patients (2974 [2283, 18055], p=0.008). Diabetic patients had significantly lower ET(A) receptor levels than non-diabetic patients (455 [167, 1496] vs. 1660 [700, 3190], respectively, p = 0.003). CONCLUSIONS: Multivariate analysis demonstrated that the presence of systemic hypertension was the only independent predictor of log ET(A) receptor expression and log ET-1 expression, while insulin-dependent diabetes was negatively correlated with ET(A) receptor expression. ETB receptor expression was not correlated with any predictor. Systemic hypertension is associated with increased ET-1 and ET(A) receptor mRNA expression, whereas insulin-dependent diabetes down-regulates ET(A) receptor mRNA expression in the internal mammary artery in patients with coronary artery disease undergoing bypass grafting.

Nyckelord

Aged

Coronary Artery Bypass

Coronary Artery Disease/*physiopathology/surgery

Diabetes Mellitus

Type 1/*physiopathology

Down-Regulation/physiology

Endothelin-1/genetics

Female

Gene Expression/physiology

Humans

Hypertension/*physiopathology

Male

Mammary Arteries/*physiology/surgery

Middle Aged

Multivariate Analysis

Predictive Value of Tests

RNA

Messenger/metabolism

Receptor

Endothelin A/*genetics

Receptor

Endothelin B/genetics

Vasodilation/physiology

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