Background and aim: Several studies demonstrated a six-fold increase in plasma concentration of endothelin-1 (ET-1) in diaysis patients (hemodialysis and peritoneal dialysis) compared to healthy control subjects. However, the effects of ET-1 on respiratory function in these patients are less known. The aim of this study was to determine the potential differences in spirometric values in relation to ET-1 levels.
Methods: The study included 28 patients (15 male, 13 female, mean age 55.9 +/- 16. 2 years) with end stage renal diseases (ESRD) receiving regular hemodialysis (HD), 23 patients (10 males, 13 females, mean age 55.8 +/- 15.8 years) with ESRD treated with continuous ambulatory peritoneal dialysis (CAPD) without any cardiovascular or respiratory diseases, and 30 healthy volunteers (14 male, 16 female, mean age 51.8 +/- 15.6 years) in control group. In each of the three groups the participants were divided into two additional sub-groups according to the serum levels of ET-1. The spirometry values were recorded before the onset of hemodialysis and prior to emptying the peritoneal cavity in CAPD patients. The results were analyzed using standard statistical methods (Student's t-test).
Results: Patients who were treated with HD or CAPD were found to have significant difference in values of most pulmonary function parameters between subjects with ET-1 levels lower than 6.6 pg/ml and subjects with ET-1 levels higher than 6.6 pg/ml. In the control group there was no difference in pulmonary function parameters in correlation with ET-1 levels. ET-1 values in patients of both dialysis groups were significantly higher compared to healthy subjects.
Conclusions: Higher levels of ET-1 in dialysis patients over healthy subjects is associated with lower parameters of lung function tests. A possible pathophysiological mechanism for deterioration of pulmonary function might be explained by progression of inflammation, pulmonary oedema also known as "uraemic lung" or/and the progression of pulmonary hypertension.