Plasma immunoreactive endothelin levels in children with cystic fibrosis

Plasma immunoreactive endothelin levels were determined in 31 children and adolescents with cystic fibrosis and it was examined whether these levels c orrelated with the severity of the disease. The study comprised 16 cystic f ibrosis patients (mean (SD) age 13.0 (4.9) y) with impaired lung function ( Group A), 15 cystic fibrosis patients (11.2 (5.5) y) with unimpaired lung f unction (Group B) and 28 healthy controls (10.6 (4.3) y) (Group C). The sel ection and classification of patients into groups was based on criteria inc luding the grade of finger-clubbing, the Brasfield chest radiograph score a nd spirometric and arterial blood gas values. In all subjects, plasma immun oreactive endothelin, atrial natriuretic peptide, renin, serum aldosterone levels and serum and urine electrolytes were measured. Conclusions: Plasma endothelin levels were significantly higher in Group A (range 2.5-8.4 pg/ml, median 3.2 pg/ml) than those in Group B (1.3-3.8 pg/m l, median 2.0 pg/ml, p < 0.001) and Group C (1.5-3.5 pg/ml, median 2.5 pg/m l, p < 0.001), whereas they did not differ between groups B and C. They cor related positively with the severity of finger-clubbing, heart rate, arteri al blood PCO2, plasma atrial natriuretic peptide levels and serum aldostero ne levels and negatively with the arterial blood PO2, forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1) and the Brasfield chest ra diograph score. In multivariate regression analysis PO2 was the only indepe ndent factor found to significantly affect plasma endothelin levels. In con clusion, plasma immunoreactive endothelin levels are increased in cystic fi brosis patients with impaired pulmonary function and are related to the sev erity of the disease.