In this article the authors compared the acute oxidative stress following intravenous iron sucrose and iron dextran administration in 20 patients on chronic hemodialysis. They measured the mean changes in plasma iron, non-transferrin-bound iron, plasma ascorbic free radical and protein carbonyls 10 minutes after intravenous injection, and concluded that increased oxidative stress was found only after iron sucrose. However, as stated by the authors, measurement of both plasma iron (indeed, labile iron) and non-transferrin-bound iron can be disturbed by assay interferences. In addition, it must be noted that labile iron in iron-carbohydrate complexes is available for direct transfer to transferrin and other proteins, although this does not mean that it must happen inmediately after intravenous administration, but most probably during the vascular residence time of the different compounds. On the other hand, increased levels of oxidative markers after iron sucrose administration have not been observed in other studies. The authors relate the increase in plasma ascorbic free radical and protein carbonyls oversaturation to increases in non-transferrin-bound iron due to transferrin oversaturation, but this may have not been correctly measured (see above).
In summary, although the authors offer some interesting data, the study includes a small sample size and no time-course measurements, and the discussion is too speculative. Obviously, futher research in this field is needed.
– Manuel Muoz