Expression of endothelin-1 in amniotic fluid embolism and possible pathophysiological mechanism

Since endothelin is a potent vasoconstrictor and bronchoconstrictor, endothelin-1 expression in the lung was investigated using immunohistological techniques in two cases of amniotic fluid embolism. Intense expression of endothelin-1 was observed in amniotic squames while weaker staining was seen in alveolar epithelium, bronchiolar epithelium and intraalveolar macrophages and focally in vascular endothelium. Endothelin-1 may play a role in the early and transient haemodynamic alteration of pulmonary hypertension in amniotic fluid embolism.