Heme Synthesis in Anemia of the Uremic State

Anemia is a constant complication of uremia. As it has been suggested that uremic toxins (middle molecules) play an important role in the mechanism of anemia, we studied the activities of three heme-synthesizing enzymes: δ-aminolevulinic acid dehydratase, porphobilinogen deaminase and ferrochelatase. In 26 patients on regular dialysis therapy, all three enzymes had significantly lower values than in normal control subjects. From our results, it can be assumed that the decreased heme biosynthesis in chronic uremic patients might be caused by a lack of erythropoietin or by uremic toxins inhibiting erythropoietin and/or heme-synthesizing enzymes.