endothelin-1 and Cystic-Fibrosis

Pulmonary hypertension is rare in chronic respiratory diseases but has a strong impact on the prognosis and is partly underlined by factors other than hypoxaemia. The aim of the present study was to assess the potential role of endothelin-1 (ET-1) and nuclear factor (NF)-kappaB vasoconstrictive pathways in pulmonary hypertension. The effects of ET-1 receptors blockers (BQ 123 and 788) and of genistein were assessed on response to acetylcholine of pulmonary vascular rings from cystic fibrosis (CF) lung transplant recipients (n = 23). NF-kappaB and ET-1 receptor expression was immunodetected in pulmonary arteries and quantitated using Western blotting. ET-1 vascular content was quantitated using ELISA. In total, 14 out of 23 subjects exhibited strongly impaired pulmonary vasodilation (p<0.01 versus nine out of 23 subjects with a normal response) associated with an activation of ET-1 receptors A and NF-kappaB pathways. Genistein restored vasodilation in subjects with an abnormal response. Pulmonary vascular dysfunction is frequent in end-stage CF, involving the NF-kappaB pathway and that of ET-1 through ET-1 receptor A (ETAR). These data leave a conceptual place for ETAR blockers and isoflavones in the management of the devastating vascular complication of chronic obstructive respiratory diseases such as CF.

Topics: Acetylcholine; Adult; Cystic Fibrosis; Dose-Response Relationship, Drug; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression Regulation; Genistein; Homeostasis; Humans; Hypertension, Pulmonary; Male; NF-kappa B; Vascular Diseases

Many patients with cystic fibrosis (CF) have airflow obstruction, with peribronchial and peribronchiolar fibrosis. Endothelin (ET)-1 is a potent bronchoconstrictor with mitogenic activity for airway smooth muscle. Do the levels of ET-1 in sputum support the putative role of ET-1 in contributing to airway remodelling with airflow obstruction in CF? The levels of ET-1 in plasma, saliva and sputum from 12 adult patients with CF not in exacerbation (spontaneous sputum), 17 normal control subjects (induced sputum) and as an additional control population, nine patients with stable chronic obstructive pulmonary disease (COPD) (seven spontaneous sputum) were measured. Total and differential sputum cell counts were performed. Median (interquartile range) sputum ET-1 level was elevated in CF (77.6 (29.0-122.8) pg x mL(-1)) compared to normal subjects (6.00 (2.8-14.8) pg x mL(-1)) and COPD (16.4 (6.8-38.2) pg x mL(-1)), and in COPD compared to normal subjects. There was a slight elevation of plasma ET-1 level in CF (5.3 (3.2-6.0) pg x mL(-1)) compared to normal subjects (3.1 (1.7-4.4) pg x mL(-1)) and COPD (3.3 (2.7-4.2) pg x mL(-1)). Sputum and saliva ET-1 levels were significantly higher than plasma levels in all groups, suggesting local production or release in the respiratory tract. Sputum differential cell counts revealed pronounced neutrophilia in CF and COPD compared to normal subjects. Sputum endothelin-1 concentrations are elevated in cystic fibrosis sputum compared to chronic obstructive pulmonary disease, and in cystic fibrosis and chronic obstructive pulmonary disease compared to normal subjects. The role of endothelin-1 in contributing to airflow obstruction through bronchoconstriction and mitogenesis in cystic fibrosis needs now to be explored.

Topics: Adolescent; Adult; Aged; Cell Count; Cystic Fibrosis; Endothelin-1; Female; Humans; Lung Diseases, Obstructive; Male; Middle Aged; Sputum