Iron release in erythrocytes from patients with β-thalassemia

• Published in: Free radical research Vol. 30; no. 5; pp. 407 - 413
• Main Authors: Ciccoli, Lucia, Signorini, Cinzia, Scarano, Clelia, Rossi, Viviana, Bambagioni, Sabrina, Ferrali, Marco, Comporti, Mario
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.01.1999; Taylor & Francis
• Subjects: Adult; beta-Thalassemia - metabolism; Erythrocytes; Erythrocytes - drug effects; Erythrocytes - metabolism; Fetal Hemoglobin - metabolism; foetal hemoglobin (HbF); Glutathione - metabolism; Humans; Iron - metabolism; iron release; Monomethylhydrazine - pharmacology; oxidative stress; Phenylhydrazines - pharmacology; Reference Values; β-thalassemia
• ISSN: 1071-5762; 1029-2470
• DOI: 10.1080/10715769900300441

Our previous studies have shown that iron is released in a free (desferrioxamine-chelatable) form when erythrocytes undergo oxidative stress (incubation with oxidizing agents or aerobic incubation in buffer for 24-60 h (a model of rapid in vitro ageing)). The release is accompanied by oxidative alterations of membrane proteins as well as by the appearance of senescent antigen, a signal for termination of old erythrocytes. In hemolytic anemias by hereditary hemoglobin alterations an accelerated removal of erythrocytes occurs. An increased susceptibility to oxidative damage has been reported in β-thalassemic erythrocytes. Therefore we have investigated whether an increased iron level and an increased susceptibility to iron release could be observed in the erythrocytes from patients with β-thalassemia. Erythrocytes from subjects with thalassemia intermedia showed an extremely higher content (0 time value) of free iron and methemoglobin as compared to controls. An increase, although non-statistically-significant, was seen in erythrocytes from subjects with thalassemia major. Upon aerobic incubation for 24 h the release of iron in β-thalassemic erythrocytes was by far greater than in controls, with the exception of thalassemia minor. When the individual values for free iron content (0 time) seen in thalassemia major and intermedia were plotted against the corresponding values for HbF, a positive correlation (P < 0.001) was observed. Also, a positive correlation (P < 0.01) was seen between the values for free iron release (24 h incubation) and the values for HbF. These results suggest that the presence of HbF is a condition favourable to iron release. Since in β-thalassemia the persistance of HbF is related to the lack or deficiency of β chains and therefore to the excess of α chains, the observed correlation between fre iron and HbF, is consistent with the hypothesis by others that excess of α chains represents a prooxidant factor.