Plasma endothelin-1 levels in patients with peripheral arterial occlusive disease at different Fontaine's stages

Endothelin-1 (ET-1) is a potent vasoconstrictor and mitogenic peptide produced and secreted by endothelial cells, which can play a potential role in the development of atherosclerosis and in the pathophysiology of extreme vasoconstriction of various diseases.

To assess plasma endothelin-1 (ET-1) concentrations in patients with peripheral arterial occlusive disease (PAOD) at different Fontaine's stages, we measured plasma ET-1 by radioimmunoassay in 14 stage II PAOD patients (12 men, 2 women; mean age 59.5 +/- 3.4 years) and in 10 stage III-IV PAOD patients (8 men, 2 women, mean age 61.2 +/- 3.3 years). Ten normal subjects (8 men, 2 women, mean age 58.1 +/- 7.2 years) were considered as controls.

Mean (+/- SD) plasma ET-1 levels, as measured by radioimmunoassay, were significantly greater in stage II and stage III-IV PAOD patients than in control subjects (4 +/- 0.4 and 5 +/- 0.4 pmol/L vs 2.5 +/- 0.6 pmol/L, respectively, p < 0.001). Furthermore, plasma levels of ET-1 in stage III-IV patients were significantly higher than in stage II patients (p < 0.01). A significant correlation was found between plasma ET-1 levels and number of the arterial obstructive lesions in PAOD patients (r = 0.698; p < 0.0001). No significant correlation was found between plasma ET-1 concentrations and pain-free walking distance (r = -0.279, p = 0.333, in stage II patients; r = 0.137, p = 0.705, in stage III-IV patients), and between plasma ET-1 levels and ankle/arm pressor index (r = 0.032, p = 0.913, in stage II patients; r = 0.149, p = 0.681, in stage III-IV patients) in the PAOD patients.

Raised plasma ET-1 could be a sensible marker both of endothelial damage and disease extension. It could also promote the progression of atherosclerotic plaques and enhance the microvascular resistance in these patients.