A Comparative Study of the Predictive Values of Urinary Acute Kidney Injury Markers Angiogenin and Kidney Injury Molecule 1 for the Outcomes of Kidney Allografts

BACKGROUND Whether injury-related molecules in urines of individuals with ischemia-reperfusion injury (IRI) are independent predictors of graft outcomes and provide additional information compared with usual risk factors remains to be established. METHODS We explored a cohort of 244 kidney transplant recipients who systematically had a urine collection 10 days after transplantation. The injury-related markers kidney injury molecule-1 (KIM-1) and angiogenin (ANG) levels in urines were measured. We determined the prognostic values of these markers on graft outcomes. RESULTS Urinary KIM-1 and ANG concentrations were strongly correlated to each other and were significantly and independently associated with cold ischemia time, delayed graft function, and plasma creatinine 10 days after transplantation, indicating that these markers reflect the severity of IRI. However, urinary ANG and KIM-1 were not predictive of histological changes on protocol biopsies performed 3 and 12 months after transplantation. Finally, urinary ANG and urinary KIM-1 were not associated with graft survival. CONCLUSIONS Together, our results indicate that, in a cohort of 244 kidney transplant recipients, urinary ANG and KIM-1 levels in a single measurement 10 days after transplantation reflect the severity of IRI after kidney transplantation, but are neither independent predictors of renal function, histological changes and graft survival.