Endothelial nitric oxide synthase in the lungs of patients with pulmonary hypertension

To the Editor: In their paper in the July 27 issue,¹ Giaid and Saleh demonstrate reduced expression of endothelial nitric oxide synthase in the lungs of patients with pulmonary hypertension. Although these data are extremely provocative, we have several reservations about this study. First, the paper does not present a balanced view of the current literature on the role and expression of nitric oxide in normal lung and in pulmonary hypertension. For example, the authors state that “nitric oxide plays an important part in… maintaining low pressure in the normal pulmonary circuit.” This remains controversial. Nishiwaki et.