Lipopolysaccharide evokes resistance to erythropoiesis induced by the long-acting erythropoietin analogue darbepoetin alfa in rats.

Abstract

Anemia is common in patients with sepsis but its mechanism is unknown. We tested the hypothesis that effects on erythropoiesis evoked by darbepoetin alfa (DA), a long-acting erythropoietin analog, are diminished by lipopolysaccharide (LPS). We performed a prospective, controlled, randomized animal study (male Lewis rats n = 44). The interventions we used were intraperitoneal injection of Escherichia coli LPS (10 mg/kg) or vehicle followed by either DA (25 microg/kg) or vehicle (four experimental groups). Blood and reticulocyte counts and variables of iron metabolism were measured at baseline and 3 and 14 days after interventions. Animals treated with DA alone showed an eightfold increase in reticulocyte count from baseline on Day 3, whereas no increase was seen in animals administered LPS or LPS/DA. On Day 14, the red blood cell count and hemoglobin concentration had increased by approximately 10% from baseline (P < 0.001) in the DA group but had decreased after LPS on Days 3 and 14 (P < 0.05) and in animals administered LPS/DA. Consumption of iron was seen on Day 3 in the DA group but not after LPS or LPS/DA combined. Values of ferritin and transferrin did not change between groups. LPS abolishes erythropoiesis and iron use evoked by DA and this is accompanied by a decrease in hemoglobin concentration and red blood cell concentration. Accordingly, endotoxin suppresses DAs ability to increase erythropoiesis.