Risk Prediction of Kidney Function in Long-term Kidney Transplant Recipients

Krzysztof Batko ¹ Anna Sączek ¹ Małgorzata Banaszkiewicz ¹ Jolanta Malyszko ² Ewa Koc-Zorawska ³ Marcin J Zorawski ³ Katarzyna Siek ¹ Karolina Niezabitowska ¹ Marcin Krzanowski ¹ Alina Bętkowska-Prokop ¹ Andrzej Kraśniak ¹ Katarzyna Krzanowska ^1*

• ¹ Jagiellonian University Medical College, Kraków, Poland
• ² Medical University of Warsaw, Warsaw, Masovian, Poland
• ³ Medical University of Bialystok, Bialystok, Podlaskie Voivodeship, Poland

Background: Limited tools exist for predicting kidney function in long-term kidney transplant recipients (KTRs). Elabela, apelin and the APJ receptor constitute an axis that regulates vascular and cardiac physiology in opposition to the renin-angiotensin-aldosterone system. Methods: Longitudinal, observational cohort of 102 KTRs who maintained graft function for at least 24 months, with no acute rejection history or active infection upon presentation. Serum apelin, elabela, fibroblast growth factor 23 (FGF-23) and α Klotho were tested using enzyme-linked immunoassay and compared with a control group of 32 healthy controls (HCs).Results: When comparing with HCs, higher serum FGF-23 (P<0.01), elabela (P<0.01) and apelin (P=0.04), but lower α Klotho (P=0.02) concentrations were observed in long-term KTRs. Most KTRs had stable trajectories of renal function. Mean estimated glomerular filtration (eGFR) over 2-year follow-up was associated with significantly lower odds of graft loss (OR 0.04, 95% CI 0.01-0.15; p<0.001). Baseline renal function was significantly correlated with mineral-bone markers (log[FGF-