UPTAKE AND STORAGE OF RETINOL AND RETINYL ESTERS IN BONE-MARROW OF CHILDREN WITH ACUTE MYELOID-LEUKEMIA TREATED WITH HIGH-DOSE RETINYL PALMITATE

Twenty-one children with AML, who achieved complete remission with cyt ostatics, were treated with high doses of retinoids after 2 remission was achieved. They were given 52 mu mol retinyl palmitate/m(2) (50 000 International Units/m(2)) daily for at least 2 years thereafter. Thir teen of the children are still in complete remission with a mean obser vation time of 103 months. Due to the positive effects of retinoids se en in the treatment of AML, we have studied uptake of lipoprotein-asso ciated retinyl esters in bone marrow cells and peripheral leukocytes i n vivo. An oral load of 104 mu mol/m(2) (100 000 International Units/m (2)) retinyl palmitate resulted in a doubling of the concentration of total retinol in bone marrow cells and peripheral leukocytes after 5 h ours. However, in the fasting state no significant difference was obse rved between the content of total retinol in bone marrow cells from co ntrols and from patients receiving retinyl palmitate daily for years. Our study suggests that bone marrow cells take up retinyl esters postp randially, but do not store retinoids.