Nitric oxide and endothelin-1 in chronic renal failure

Abstract

Nitric oxide (NO) and endothelin-1 (ET-1) are two substances that take part in the regulation of vascular smooth muscle tone. ET-1 is a vasoconstrictor peptide and NO is a vasodilating molecule. There have been contradictory reports of the plasma levels of these substances in patients with chronic renal failure (CRF). We studied plasma levels of ET-1 and NO in hypertensive and normotensive patients with CRF either on dialysis or on non-dialysis treatment. A total of 41 patients were studied, 23 males and 18 females with mean age of 50.39±14.46 years. The control group consisted of healthy subjects (22 males and 8 females) with a mean age of 46.50±8.21 years. The plasma levels of ET-1 were significantly higher and NO levels were lower in the CRF patients than in controls (p<0.05). The plasma levels of NO were lower in patients hypertensive CRF than in normotensive CRF patients (p<0.05). Plasma ET-1 levels, however, did not show any difference (p<0.05). However, plasma NO levels were lower in patients on haemodialysis than in patients on non-dialysis conservative treatment (p<0.01). Except for the negative correlation between the plasma NO and creatinine levels (p<0.01), there were not any relationship between the plasma NO and ET-1 levels, renal function tests (BUN, creatinine), duration of disease and hemodialysis. We concluded that hypertension in CRF has a multifactorial aetiology and that decrease of NO levels, and disturbance of the balance between NO and ET-1 levels might be more important than the above factors alone.