Effects of vitamin C on intracoronary L-arginine dependent coronary vasodilatation in patients with stable angina.
OBJECTIVE
To assess the effects of intravenous vitamin C administration on the vasomotor responses to intracoronary L-arginine infusion in epicardial coronary arteries.


METHODS
28 patients with coronary artery disease and stable angina were enrolled in the study. Eight patients received intracoronary infusions of 150 micromol/min L-arginine before and after intravenous infusion of vitamin C, 10 patients received intracoronary infusions of 150 micromol/min L-arginine before and after intravenous infusion of normal saline, and 10 patients received intracoronary normal saline before and after intravenous infusion of vitamin C. The diameter of proximal and distal coronary artery segments was measured by quantitative angiography.


RESULTS
Infusion of L-arginine caused significant dilatation of both proximal (4.87 (0.96)%, p < 0.01 v normal saline) and distal (6.33 (1.38)%, p < 0.01 v normal saline) coronary segments. Co-infusion of vitamin C and L-arginine dilated proximal coronary segments by 8.68 (1.40)% (p < 0.01 v normal saline, p < 0.01 v L-arginine) and distal segments by 13.07 (2.15)% (p < 0.01 v normal saline, p < 0.01 v L-arginine). Intravenous infusion of vitamin C caused a borderline increase in proximal and distal coronary segment diameters (1.93 (0.76)% and 2.09 (1.28)%, respectively, not significant).


CONCLUSIONS
L-arginine dependent coronary segment vasodilatation was augmented by the antioxidant vitamin C in patients with coronary artery disease. Thus, vitamin C may have beneficial effects on nitric oxide bioavailability induced by L-arginine.
Tousoulis
D
D
Athens University Medical School, Athens, Greece. drtousoulis@hotmail.com
Xenakis
C
C
Tentolouris
C
C
Davies
G
G
Antoniades
C
C
Crake
T
T
Stefanadis
C
C
D000787:Angina Pectoris / Q000503:physiopathology*; D000975:Antioxidants / Q000494:pharmacology*; D001120:Arginine / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects*; D004338:Drug Combinations; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D014664:Vasodilation
D000975:Antioxidants; D004338:Drug Combinations; D009569:Nitric Oxide; D001120:Arginine; D001205:Ascorbic Acid