Oxygen Sensing in the Ductus Arteriosus: Endothelin Still a Player

To the Editor: In a recent issue of Circulation Research , Hong et al1 provided additional data in support of a mitochondrial mechanism for oxygen sensing in the ductus arteriosus. While commending the authors on the advance in this area, I find objectionable their hasty dismissal of an alternative scheme implicating endothelin in the same process. Far from being a concept exclusively originating from our work, as implied in the article, this position is espoused by diverse groups.2 In taking their conclusion to the fore, Hong et al1 quoted 3 publications that warrant a comment. The first one by Michelakis et al,3 being based on experiments with the isolated human ductus, negates a role for endothelin because the combined inhibition of its synthesis and action (with phosphoramidon …