Vitamin C improves endothelial function of epicardial coronary arteries inpatients with hypercholesterolaemia or essential hypertension - assessed by cold presser testing
M. Jeserich et al., Vitamin C improves endothelial function of epicardial coronary arteries inpatients with hypercholesterolaemia or essential hypertension - assessed by cold presser testing, EUR HEART J, 20(22), 1999, pp. 1676-1680
Aims There is evidence that formation of free radicals increases in patient
s with hypertension or hypercholesterolaemia, which may contribute to endot
helial dysfunction of epicardial coronary arteries due to inactivation of t
he vasodilator NO. The present study was designed to test whether the abnor
mal constriction of epicardial coronary arteries due to sympathetic stimula
tion by the cold presser test in patients with essential hypertension or hy
percholesterolaemia could be reversed by administration of the antioxidant
vitamin C.
Methods and Results In 28 patients without relevant coronary artery stenosi
s the cold presser test was performed before and after a 3 g infusion of vi
tamin C. In five normal controls the cold presser test led to a similar inc
rease in luminal area before and after vitamin C (3.7 +/- 1.3% and 1.9 +/-
0.8%, ns vs before vitamin C). In nine hypercholesterolaemic patients the c
old presser test led to a -14.1+/-28% reduction in cross-sectional area bef
ore vitamin C. This constriction was significantly improved after vitamin C
to -7.6%+/-2.0, P=0.027 vs before vitamin C. In nine hypertensive patients
, the cold presser test led to a -17.1+/-3.2% decrease in cross-sectional a
rea before vitamin C, which was improved to -7.1+/-3.1 after vitamin C, P=0
.004 vs before vitamin C. This increase in luminal area was significant in
each group in comparison with normal controls teach P<0.05). Administration
of saline (placebo group, five patients) had no significant effect on cold
presser test-induced constriction (-6.9+/-3.9% before and -6.8+/-3.7% afte
r saline).
Conclusion The antioxidant vitamin C reverses cold presser test-induced vas
oconstriction of epicardial coronary arteries in patients with hypertension
or hypercholesterolaemia. Our data suggest that enhanced oxidative stress
contributes to impaired endothelial function in this patient population. (C
) 1999 The European Society of Cardiology.