Erythrocyte 2,3-DPG, ATP and oxygen affinity in hemodialysis patients.

Patients on a chronic hemodialysis regimen were studied with respect to their erythrocyte adaptation to anemia. Erythrocyte 2,3-diphosphoglycerate (DPG) concentration was suboptimal compared with that of anemic patients who were not uremic. In uremic patients erythrocyte 2,3-DPG correlated poorly with hemoglobin level but more strongly with plasma pH. Differences between observed levels of erythrocyte 2,3-DPG and the values predicted using data from other anemic patients also correlated with pH. Gradual correction of plasma pH with oral sodium bicarbonate resulted in a substantial increase in erythrocyte 2,3-DPG and a decrease in oxygen affinity. Therefore, maintenance of normal pH in uremic subjects may improve tissue oxygenation. On the other hand, the rapid correction of acidosis during dialysis resulted in increased oxygen affinity. This response was due to the direct effect of pH on oxygen affinity in the absence of a significant change in erythrocyte 2,3-DPG or adenosine triphosphate (ATP) during hemodialysis. Erythrocyte ATP but not 2,3-DPG correlated with serum inorganic phosphate in uremic subjects. A 21% reduction of serum phosphate produced by ingestion of aluminum hydroxide gel had no significant effect on these variables.

Studies on erythropoiesis in uremic and post-transplant (renal) patients utilizing radioactive iron and chromium.

The association of anemia with chronic renal disease is well known. The striking hematologic improvement following a successful renal allotransplantation led to the present study. Using radioactive (59)Fe, ferrokinetic measurements were carried out in nine uremic patients (seven with and two without anemia), four post-allotransplant cases, three patients with iron deficiency anemia and a group of five normal subjects. Erythrocyte life-span was calculated by (51)Cr-labelled, autotransfused red cells in all patients who had had transplants and in three patients with renal anemia. The results showed that in patients with renal anemia the plasma radioiron clearance was slightly delayed but the (59)Fe incorporation into the circulating erythrocytes was significantly decreased. Red cell life-span was moderately shortened in two out of three uremic patients investigated. The findings constitute evidence of ineffective erythropoiesis in patients with renal anemia. By comparison, the four transplant patients showed normal (59)Fe plasma clearance and red cell incorporation; the (51)Cr erythrocyte survival was normal in all four patients.