ENDOTHELIN-1 IN PRIMARY PULMONARY-HYPERTENSION AND THE EISENMENGER SYNDROME

Primary pulmonary hypertension (PPH) is an uncommon condition, the etiology and pathogenesis of which are unknown. PPH is histologically characterized by endothelial injury and the proliferation of pulmonary arterial smooth muscle cells. A role for vasoconstriction in the pathophysiology of PPH is supported by the possibility of spontaneous reversal at early stages and by the greater than expected incidence of Raynaud's phenomenon in patients with PPH.1 The mechanism of the initiation of vasoconstriction, and the perpetuation or progression of the obstruction are unclear. Endothelin-1 (ETL1), a newly isolated peptide from vascular endothelial cells,2 has potent vasoconstricting activity and induces vascular smooth muscle cell proliferation.3,4 These observations suggest that ETL1 may have an important role in the increased vascular tone or medial hypertrophy, or both, of small arteries observed in PPH. In this study, we measured venous plasma ETL1 concentrations in patients with PPH, and compared them with those found in patients with pulmonary hypertension secondary to congenital heart defects and in normal subjects. © 1993.