Endothelial activation in patients with cardiac syndrome X.
BACKGROUND
The presence of endothelial dysfunction with increased endothelin-1 plasma concentrations in patients with cardiac syndrome X is still under debate. The aim of the present study was to evaluate the presence of endothelial dysfunction in patients with cardiac syndrome X.


RESULTS
++Endothelin-1 levels were evaluated with a sensitive radioimmunoassay with previous purification through reverse phase HPLC in 24 patients (3 men and 21 women, mean age 54+/-7 years) with typical angina, instrumental evidence of ischemia, and normal coronary angiograms both under baseline conditions and after oral glucose load (75 g D-glucose). We also measured plasma nitrite-plus-nitrate levels, a sharp index of endothelial nitric oxide production, and circulating concentrations of the soluble fraction of the endothelial adhesion molecule vascular cell adhesion molecule-1, a well-recognized marker of early endothelial dysfunction. Fourteen healthy subjects (1 man and 13 women, mean age 47+/-15 years) served as controls. There were no significant differences in baseline plasma endothelin-1 concentrations between patients and control subjects (0.55+/-0.34 versus 0.48+/-0.22 pg/mL, P=0.503). Plasma nitrite-plus-nitrate and soluble vascular cell adhesion molecule-1 concentrations were also similar between the 2 groups. After glucose ingestion, circulating endothelin-1 concentrations were significantly higher in patients with cardiac syndrome X than in control subjects (P<0.03 at 60, 90, and 120 minutes).


CONCLUSIONS
Our findings show that no basal endothelial damage is present in patients with cardiac syndrome X. Nevertheless, increased responsiveness of endothelin-1 to glucose loading suggests that patients with cardiac syndrome X present an increased susceptibility to releasing endothelin-1 under stressful circumstances.
Desideri
G
G
Department of Internal Medicine and Public Health, University of L'Aquila, L'Aquila, Italy. gbdesi@freemail.it
Gaspardone
A
A
Gentile
M
M
Santucci
A
A
Gioffrè
P A
PA
Ferri
C
C
D002851:Chromatography, High Pressure Liquid; D019332:Endothelin-1 / Q000097:blood*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D017566:Microvascular Angina / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology*; D008875:Middle Aged; D011863:Radioimmunoassay
D019332:Endothelin-1