Model to Study the Effects of Ethanol on Erythropoiesis

DESCRIPTION (Scanned from the applicant's description): Chronic ingestion of ethanol has been proposed to hasten the development and increase the severity of megaloblastic anemia in human patients, as well as cause anemia in patients with normal folate status. Proposed mechanisms for red cell abnormalities in alcoholic patients include attenuation of erythropoietin (EPO) production by ethanol, decreased sensitivity of erythroid precursor cells to EPO, direct toxic effects of ethanol on erythroid progenitors, and an antifolate activity of ethanol. The contributions of each in the cause of the erythroid abnormities associated with alcoholism have not been studied simultaneously. In the same model system and it is therefore unclear which of the potential mechanisms is physiologically greatest importance. A mouse model of chronic ethanol ingestion will be developed in order to determine the significance of each of these potential mechanisms, and further, to allow for the investigation of the role of gender in the development of hematologic abnormalities associated with chronic ethanol ingestion. Direct toxic effects of ethanol on erythroid progenitors will be determined by enumerating early erythroid progenitors in ethanol fed and control mice, by measuring the ability of ethanol fed and control mice to recover from acute anemia and by culturing erythroblasts isolated from ethanol fed and control mice in different concentrations of ethanol to determine the effect of ethanol on the viability and extent of terminal differentiation of erythroblasts. EPO production will be assessed in anemic ethanol fed and control mice. It will be determined if ethanol exacerbates or accelerates the hematologic symptoms of folate deficiency by subjecting mice to folate deficient diets with or without ethanol supplementation. Erythroblasts will be isolated from folate deficient mice on the folate deficient diet and from mice on the folate deficient diet supplemented with ethanol. The ability of erythroblasts to undergo terminal differentiation in vitro after correcting the folate deficiency in the presence or absence of ethanol will be investigated to determine if ethanol delays or inhibits the recovery form folate deficiency. The results of this study may be significant for the treatment of anemias and associated illnesses in alcoholics. Higher levels of folate supplementation may be required in the initial treatment of alcoholic patients if it is found that ethanol has direct or residual effects on folate metabolism in erythroblasts. Alteration of the in vivo bioavailablity of folate may be indicated if the effects of ethanol on erythroblasts are more pronounced in vivo than in vitro. Alternative forms of delivery of folate (parenteral vs oral) and the avoidance of drugs that have anti-folate activity for treatment of alcoholics (anticonvulsives and certain broad spectrum antibiotics) might thus be warranted order to increase the bioavailabilty of administered folate.