GDF15 is related to anemia and hepcidin in kidney allograft recipients.

UNLABELLED: Anemia is more prevalent in renal transplant recipients than in GFR-matched chronic kidney disease patients. Hepcidin is a small defensin-like peptide whose production by hepatocytes is modulated in response to anemia, hypoxia or inflammation. Growth differentiation factor 15 (GDF15) was recently identified as a hepcidin-suppression factor that is expressed at high levels in patients with ineffective erythropoiesis. The aim of the study was to assess GDF15 levels with relation to iron parameters in 62 stable kidney allograft recipients maintained on triple immunosuppressive therapy.
METHODS: Complete blood count, urea, creatinine, and iron status were assessed by standard methods. We measured GDF15, hepcidin, hemojuvelin, IL-6 and NGAL with commercially available assays.
RESULTS: Mean levels of GDF15, NGAL, hepcidin and hemojuvelin were significantly higher in kidney allograft recipients when compared to the control group (p < 0.001 for all). GDF15 was significantly higher in patients with anemia according to the WHO definition when compared to their nonanemic counterparts (p < 0.05). GDF15 levels were not dependent on the type of immunosuppressive therapy. In univariate analysis GDF15 was related to kidney function (creatinine r = 0.39, p < 0.01, eGFR by MDRD r = -0.37, p < 0.01), urea (r = 0.39, p < 0.01), uric acid (r = 0.42, p < 0.01), hepcidin (r = -0.32, p < 0.01), IL-6 (r = 0.28, p < 0.05), hemoglobin (r = -0.32, p < 0.05), and NGAL (r = -0.35, p < 0.01). GDF15 was not related to serum iron, or ferritin. In multivariate analysis, hepcidin was found to be a predictor of GDF15. In conclusion, our preliminary data may suggest possible mutual relations between GDF15 and hepcidin in patients with kidney disease and that GDF15 might be involved in the pathogenesis of anemia in kidney allograft recipients. However, the role of inflammation should be also elucidated.