Changes in plasma amino acids during conditioning therapy prior to bone marrow transplantation: Their relevance to antioxidant status.

Bone marrow transplant (BMT) recipients undergo a bimodal regimen of conditioning therapy, the precise prescription being dependent upon the primary disease of the individual patient. Generally, this treatment consists of chemotherapy and total body irradiation prior to transplantation, although the latter may or may not be included in the regimen. We have investigated amino acid metabolism and oxidant status in in a small series of BMT recipients before and after conditioning therapy.Plasma amino acids were measured by HPLC on 10 BMT recipients prior to commencing conditioning therapy, and again one week later before transplantation. In addition some general nutritional parameters and antioxidant components were measured. A marked decrease in the plasma concentration of a number of amino acids, especially those concerned with antioxidants, was observed over the 7 days of conditioning therapy.There is also a significant reduction in antioxidant capability, as reflected by measurements of glutathione and erythrocyte glutathione peroxidase (GSHPx), which may have an influence upon post-transplant recovery and graft function. Such a reduction in antioxidant concentrations may also have an influence upon the erythrocyte and platelet support required post-grafting.The data presented in this paper adds to the evidence for the conditional essentiality of some amino acids such as taurine and glutamine, and may support the case for specific antioxidant intervention treatment prior to, and/or after conditioning therapy together with monitoring antioxidant status during the post-grafting period.