Expressions of endothelial nitric oxide synthase in the lung tissue of patients with congenital heart disease associated with pulmonary hypertension

Objective To find whether the expressions of endothelial nitric oxide synthase (eNOS) in the lung tissue of patients with congenital heart disease (CHD) associated with pulmonary hypertension (PH) is reduced or not. Methods The expressions of eNOS were investigated by immunohistochemical analyses and reverse transcriptase polymerase chain reaction (RT PCR) assays in the lung tissue of 16 patients with CHD associated with PH (group Ⅰ) and the control group (group Ⅱ) including 16 CHD patients without PH. Results Immunohistochemical analyses revealed weak immunostaining for eNOS in the pulmonary vascular endothelial in group Ⅰ, versus the group Ⅱ( F =93.98, P 0.01). RT PCR semiquantitative assays revealed eNOS mRNA expression was reduced in group Ⅰ( F = 58.76, P 0.01), which coincided with the results of eNOS immunostaining. Conclusions The results suggest that the level of endogenous eNOS in pulmonary vascular endothelial cell is low in patients with PH. The reduced expression correlates with decreased endogenous nitric oxide (NO). Therapy with inhaled NO could provide a new, more widely applicable prophylactic approach to prevent postoperative PH.