Plasma and peritoneal endothelin levels and blood pressure in CAPD patients with or without erythropoietin replacement therapy.
The aim of the study was to determine the ET-1 concentration in peritoneal dialysate fluid and to investigate the relationship between peritoneal and plasma ET-1 levels and blood pressure in stable continuous ambulatory peritoneal dialysis (CAPD) patients with and without human recombinant erythropoietin (r-HuEPO) replacement therapy. Twenty-seven stable CAPD patients were investigated. They completed their overnight exchange at the Dialysis Centre. Blood pressure was recorded and a blood sample was drawn. Biochemical parameters and ET-1 were measured in plasma and peritoneal dialysate fluid. Mean plasma ET-1 levels were increased by about four-fold in CAPD patients. ET-1 was detectable in peritoneal dialysate fluid and a significant correlation was observed between plasma and peritoneal ET-1 concentrations (r = 0.65, p < 0.01). The peritoneal clearance of ET-1 was lower than the creatinine clearance (1.69 +/- 0.08 ml/min vs. 3.96 +/- 0.15 ml/min, p < 0.01). There was also a significant correlation between the time (months) on dialysis and plasma (r = 0.68, p < 0.01) or peritoneal dialysate ET-1 levels (r = 0.46, p < 0.05). Mean blood pressure was higher in patients treated with r-HuEPO than in untreated patients (97 +/- 4 mmHg vs. 81 +/- 4 mmHg, p < 0.01). Plasma and peritoneal dialysate ET-1 concentrations were comparable in the two groups with or without r-HuEPO replacement therapy and plasma ET-1 values correlated significantly with mean blood pressure only in r-HuEPO-treated patients (r = 0.63, p < 0.05 vs. r = 0.10, N.S. in untreated patients). In conclusion, plasma ET-1 concentrations are elevated in CAPD patients and the levels appear to increase with time on dialysis. ET-1 is cleared by the peritoneal membrane but at a much lower rate than creatinine. Blood pressure is higher in CAPD patients or r-HuEPO replacement therapy and blood pressure correlates with plasma ET-1 levels in these patients.
Lebel
M
M
Division of Nephrology, CHUQ, L'Hôtel-Dieu de Quebec Hospital, Quebec, Canada.
Moreau
V
V
Grose
J H
JH
Kingma
I
I
Langlois
S
S
D001202:Ascitic Fluid / Q000737:chemistry*; D001794:Blood Pressure; D003404:Creatinine / Q000378:metabolism; D019332:Endothelin-1 / Q000032:analysis* / Q000097:blood; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D011994:Recombinant Proteins
D019332:Endothelin-1; D011994:Recombinant Proteins; D004921:Erythropoietin; D003404:Creatinine