Expression of growth differentiation factor 15 is not elevated in individuals with iron deficiency secondary to volunteer blood donation

BACKGROUND: Low serum hepcidin levels provide a physiologic response to iron demand in patients with iron deficiency (ID). Based on a discovery of suppressed hepcidin expression by a cytokine named growth differentiation factor 15 (GDF15), it was hypothesized that GDF15 may suppress hepcidin expression in humans with ID due to blood loss. STUDY DESIGN AND METHODS: To test this hypothesis, GDF15 and hepcidin levels were measured in peripheral blood from subjects with iron‐deficient erythropoiesis before and after iron supplementation. RESULTS: Iron variables and hepcidin levels were significantly suppressed in iron‐deficient blood donors compared to healthy volunteers. However, ID was not associated with elevated serum levels of GDF15. Instead, iron‐deficient subjects' GDF15 levels were slightly lower than those measured in the control group of subjects (307 ± 90 and 386 ± 104 pg/mL, respectively). Additionally, GDF15 levels were not significantly altered by iron repletion. CONCLUSIONS: ID due to blood loss is not associated with a significant change in serum levels of GDF15.