Sodium ferric gluconate causes oxidative stress but not acute renal injury in patients with chronic kidney disease: a pilot study

Background. Intravenous (i.v) iron is widely used to treat anaemia in patients with chronic kidney disease (CKD). Although beneficial and usually well tolerated, concerns have been raised about its ability to cause oxidative stress and renal injury. Methods. To determine if i.v. iron causes oxidative stress [as assessed by plasma and urine malondialdehye (MDA)] and/or renal injury (as assessed by urinary albumin, total protein and enzymuria), we conducted a prospective, four-way randomized crossover, blinded end-point trial in eight patients with CKD. Two widely used doses of sodium ferric gluconate (125 mg infused over 1 h and 250 mg infused over 2 h) were given with or without the antioxidant N-acetylcysteine (NAC), resulting in four treatment dose–antioxidant/placebo combinations in each patient. Transferrin saturation was measured with urea polyacrylamide gel electrophoresis, MDA by high performance liquid chromatography, and albuminuria and proteinuria by standard clinical methods. Enzymuria was assessed by measurement of N-acetyl-β-d-glucosaminidase (NAG) excretion by colorimetric assay. Results. I.v. ferric gluconate infusion at both doses resulted in a marked increase in transferrin saturation and a significant increase in plasma MDA levels. Urinary MDA levels also increased at the higher dose of iron. There was no evidence of acute renal injury, as assessed by albuminuria, proteinuria or enzymuria. Pre-treatment with NAC had no effect on oxidative stress or the above urinary parameters. Conclusions. I.v. ferric gluconate caused oxidative stress (as reflected by increased MDA), but this was not associated with biochemical manifestations of acute renal injury.