IRON-INDUCED LIPID PEROXIDATION IN WHOLE BLOOD IN VITRO AS DETERMINED BY MALONDIALDEHYDE AND LUMINOL-ENHANCED CHEMILUMINESCENCE : IMPLICATIONS FOR IRO N SUPPLEMENTATION TO IRON-DEPLETED PATIENTS

Ferric hydroxide-sucrose complex is given to patients who are depleted of iron as a result of chronic haemodialysis, organ transplantation, pregnancy and other conditions. On the other hand, iron is a potent initiator of lipid peroxidation (LPO). We investigated the effect of ferric iron on whole blood of healthy human subjects in vitro. Blood was incubated with different concentrations of a ferric hydroxide-sucrose complex at 37 degrees C. Malondialdehyde (MDA). a marker of lipid peroxidation, was determined by HPLC as the MDA-thiobarbituric acid complex. Luminol-enhanced chemiluminescence (CL) in ammonia-heparinised blood was measured in a luminometer after stimulation of phagocytes with Latex. The maximum emission peak was studied both immediately after incubation (approximately 1 min) and after short whole-blood centrifugation. After incubation of both plasma and whole blood with Fe(III), MDA concentrations increased with rising iron concentrations. In the presence of 0.36 mM Fe3+(III) - a concentration expected to be reached in haemodialysis patients receiving the ferric hydroxide sucrose complex - the MDA concentrations increased significantly to 1.63 +/- 0.25 mu mol L-1 (Incubation of plasma) and 5.55 +/- 0.76 mu mol L-1 (incubation of whole blood), as compared to 0.68 +/- 0.09 mu mol L-1 and 0.84 +/- 0.11 mu mol L-1 respectively, for the control samples in the absence of the iron complex. Similarly, the maximum CL light emission rose dose-dependently (for 0.36 mM Fe(III): 14.1 +/- 1.0 arbitrary units), as compared to the control (6.2 +/- 0.6).