Increased 24-hour endothelin-1 urinary excretion in patients with chronic obstructive pulmonary disease

Abnormalities in endothelin-1 (ET-1) pulmonary metabolism have been reported in patients with pulmonary hypertension, asthma and chronic obstructive pulmonary disease (COPD). In this study we have evaluated the 24-hour urinary excretion of ET-1 in COPD patients both during acute exacerbation and stable phase of the disease. ET-1 plasma and urinary levels were measured in 13 COPD patients on admission to the hospital for an acute exacerbation and at the recovery period. Ten healthy volunteers were also studied. Determination of plasma and 24-Hour urinary ET-1 levels were carried out with a radioimmunoassay test. Plasma ET-1 levels in COPD patients were similar during exacerbation and recovery and were not significantly different from those in the healthy subjects. 24-hour urinary excretion of ET-1 was increased in COPD patients during acute exacerbation; it decreased during recovery, but remained elevated when compared to normal subjects. A negative correlation was found between arterial oxygen pressure and ET-1 excretion; no correlation was found between plasma and urinary ET-1 values. In conclusion, COPD patients excrete higher amounts of ET-1 compared to healthy subjects. Urinary ET-1 values are further increased during acute exacerbation of the disease.