Clinical significance of selected endothelial activation markers in patients with systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) is an autoimmune disease in which immunologically mediated vascular endothelial cell activation is regarded as a potential pathophysiological mechanism of systemic organ damage. We investigated selected endothelial cell activation markers in serum of patients with SLE and their relationships with systemic organ manifestations and disease activity.

METHODS: Serum levels of endothelin-1 (ET-1), soluble E-selectin, and thrombomodulin (sTM) were determined by ELISA in 76 SLE patients and in 34 healthy controls.

RESULTS: Higher serum concentrations of ET-1, sE-selectin (p < 0.05), and sTM (p < 0.001) were observed in SLE patients in comparison with controls. Significant differences of ET-1, (p < 0.01), sTM (p < 0.001), and sE-selectin serum concentrations (p < 0.01) were found between SLE patients with systemic involvement and controls. Patients with organ manifestations (n = 34) showed significantly higher serum levels of ET-1 than patients without systemic involvement (n = 42) (p < 0.05). Comparison between patients with active and inactive SLE according to SLE Disease Activity Index (SLEDAI) score showed significantly higher concentration of ET-1 in the sera of patients with active SLE compared with inactive patients and the controls (p < 0.001).

CONCLUSION: Our findings suggest that the elevated serum concentrations of ET-1, sTM, and sE-selectin reflect persisting endothelial cell activation in SLE, and point to an important role of ET-1 in the pathogenesis of internal organ involvement. Moreover, elevated ET-1 concentrations are related to disease activity, suggesting a key role of endothelial cell activation in systemic manifestations in SLE patients.