The effect of maximum storage on iron status, oxidative stress and antioxidant protection in paediatric packed cell units

Background. Premature babies may receive multiple transfusions during the first weeks of their life. Strong associations exist between the receipt of blood transfusions and the development of the major consequences of prematurity such as retinopathy and chronic lung disease. The possible physiological link between the receipt of blood and disease is unclear, but iron-induced oxidative damage and/or bacterial colonisation would promote these conditions. Premature babies are poorly equipped to deal with any increases in iron and oxidative load that they may acquire via blood transfusions. To determine whether there are any relationships between these factors, we studied iron and oxidative status of just expired (i.e. 36 days old) paediatric red blood cell (RBC) packs. Materials and methods. Just expired paediatric RBC packs were obtained from the local blood bank. The extracellular medium surrounding the RBC was separated by centrifugation and the following parameters measured: total iron concentration, total iron binding capacity, non-transferrin-bound iron [NTBI], haemoglobin, total and reduced ascorbate, and malondialdehyde concentration. Results. The extracellular fluid of the paediatric packs (n =13) was rich in iron, a high percentage of which (36%) was present as potentially toxic NTBI. It was highly redox active with limited antioxidant protection and iron-binding capacity. Discussion. The extracellular medium surrounding packed RBC could potentially be toxic if administered to patients with limited iron sequestering and antioxidant capacity, such as premature babies. Further studies are required to determine at what point during storage these changes become potentially harmful so that clinical studies can examine the optimal storage time for blood destined for premature babies.