The effect of N-acetylcysteine on renal function, nitric oxide, and oxidative stress after angiography

Renal failure induced by radiographic contrast agents is a known complication of coronary angiography, especially among patients with chronic renal failure. Recently, treatment with N-acetylcysteine (NAC) has been shown to have a protective effect but the mechanisms are unknown. We examined the hypothesis that NAC protected against contrast-induced renal impairment through effects on nitric oxide metabolism and oxidative stress.

Patients with a serum creatinine concentration above 10(6) micromol/L undergoing coronary angiography were randomly assigned to receive either NAC 1 g (N= 24) or placebo (N= 29) twice daily 24 hours before and after angiography with 0.45% saline hydration in a double-blind study. Creatinine clearance was calculated and urinary nitric oxide and F2-isoprostane excretion were measured at baseline, 24 and 96 hours after angiography.

Treatment with NAC significantly improved the effect of contrast media on creatinine clearance, and maximal beneficial effect was observed 24 hours after angiography. Creatinine clearance (mL/min) was 59.5 +/- 4.4, 64.7 +/- 5.8, and 58.7 + 3.9 at baseline, 24, and 96 hours after angiography in the NAC group, respectively, and 65.2 +/- 3.2, 51.5 +/- 3.7, and 53.6 +/- 3.9 in the placebo group, respectively (P < 0.0001). NAC treatment prevented the reduction in urinary nitric oxide after angiography. The urinary nitric oxide/creatinine ratio (micromol/mg) was 0.0058 +/- 0.0004, 0.0057 +/- 0.0004, and 0.0052 +/- 0.0004 at baseline, 24, and 96 hours after angiography in NAC group, respectively, and 0.0057 +/- 0.0007, 0.0031 +/- 0.0005, and 0.0039 +/- 0.0005 in the placebo group, respectively (P= 0.013). NAC had no significant effect on urinary F2-isoprostanes.

NAC treatment has renoprotective effect in patients with mild chronic renal failure undergoing coronary angiography that may be mediated in part by an increase in nitric oxide production.