Plasma antioxidant status after high-dose chemotherapy: a randomized trialof parenteral nutrition in bone marrow transplantation patients

Background: Chemotherapy and radiation therapy result in increased free rad ical formation and depletion of tissue antioxidants. It is not known whethe r parenteral nutrition (PN) administered during bone marrow transplantation (BMT) supports systemic antioxidant status. Objective: The aims of the study were to determine 1) whether high-dose che motherapy decreases concentrations of major circulating antioxidants in pat ients undergoing BMT and 2) whether administration of standard PN maintains systemic antioxidant concentrations compared with PN containing micronutri ents and minimal lipids alone. Design: Twenty-four BMT patients were randomly assigned to receive either s tandard PN containing conventional amounts of dextrose. amino acids, micron utrients, and lipid (120 kJ/d) or a solution containing only micronutrients (identical to those in standard PN) and a small amount of lipid (12 kJ/d). Plasma antioxidant status was measured before conditioning therapy and ser ially at days 1, 3, 7, 10, and 14 after BMT. Results: Plasma glutathione (GSH) and alpha- and gamma-tocopherol concentra tions decreased and the GSH redox state became more oxidized after conditio ning chemotherapy. Plasma cysteine concentrations were unchanged, whereas c ystine concentrations increased. Plasma vitamin C and zinc concentrations a nd GSH peroxidase activity increased over time. Plasma alpha-tocopherol con centrations were lower in patients given standard PN. Then were no differen ces in other plasma antioxidants between groups. Conclusions: A significant decline in GSH-glutathione disulfide, cysteine-c ystine, and vitamin E status occurs after chemotherapy and BMT. Standard PN does not improve antioxidant status compared with administration of micron utrients alone. Further evaluation of PN formulations to support patients u ndergoing high-dose chemotherapy and BMT are needed.