SELENIUM DEFICIENCY IN TOTAL PARENTERAL-NUTRITION

A clinical selenium (Se) responsive syndrome was observed in a patient on total parental nutrition (TPN). The Se concentrations in plasma, erythrocytes and whole blood and the activity of glutathione peroxidase, (GSHPx (EC1.11.1.9) were measured at intervals in 22 patients receiving TPN for 10 to 40 days. Plasma Se reached very low levels and included the lowest value observed in adult man (<10 ng Se/ml), similar to those in animals with Se-responsive diseases in New Zealand. Metabolic balance studies were carried out for 7 to 12 days on six of these patients during TPN. Se intake was negligible and despite the relative decrease in urinary losses (7.6 μg Se/day) and gastrointestinal and other losses, there was a marked negative balance (-10 μg Se/day). Other factors predisposing to a low Se status in these patients included living in a region with a low soil Se content and the effect of surgical stress. One patient with plasma Se of 9 ng Se/ml developed muscle pain and tenderness in the thighs with a resulting inability to walk which responded within a week to Se supplementation alone. Most of Se supplement was retained but this had produced at the end of 24 days of supplementation only an initial minor increase in plasma Se and little change in erythrocyte Se and GSHPx activity. For the patients on TPN plasma Se and 24-hr urinary Se excretion were closely related, much as reported previously for healthy New Zealand subjects and for Swedish patients on TPN. The close association between erythrocyte Se and GSHPx activity with TPN and blood transfusion could indicate that for these patients erythrocyte Se was largely determined by Se from GSHPx. This study adds further evidence for the essentiality of Se in man and demonstrates the need to consider Se supplementation in long-term TPN.