RESUMO
BACKGROUND: Identifying patients with acute kidney injury (AKI) who are at higher risk of chronic kidney disease (CKD) progression at time of AKI diagnosis remains a major challenge in clinical practice. METHODS: Kidney transcriptome sequencing was applied to identify the top up-regulated genes in mice with AKI. The product of the top-ranked gene was identified in the tubular cells and urine both in mouse and human AKI. Data from two cohorts of patients with a prehospitalization estimated glomerular filtration rate (eGFR) ≥ 45 ml/min/1.73m2 who survived for at least 90 days after AKI were used to derive and validate multivariable prediction models. AKI to CKD progression was defined as a persistent eGFR < 60 ml/min/1.73m2 and with a minimum 25% reduction from baseline eGFR 90 days after AKI in patients with prehospitalization eGFR ≥ 60 ml/min/1.73m2. AKI to advanced CKD was defined by a sustained reduction of eGFR < 30 ml/min/1.73m2 90 days after AKI in those with prehospitalization eGFR 45-60 ml/min/1.73m2. RESULTS: Kidney cytokeratin 20 (CK20) was up-regulated in injured proximal tubular cells and detectable in urine within 7 days after AKI. High concentrations of urinary CK20 (uCK20) were independently associated with the severity of histological AKI and the risk of AKI to CKD or advanced CKD progression. In Test set, the AUC of uCK20 for predicting AKI to CKD or advanced CKD was 0.80, outperformed currently used biomarkers for detecting kidney tubular injury. Addition of uCK20 to an established clinical model improved the ability for predicting AKI-CKD progression with an AUC of 0.90, and largely improved the risk reclassification. CONCLUSION: This finding highlighted uCK20 as a useful predictor for AKI to CKD progression, and may provide a tool to early identify patients at high risk of CKD following AKI. FUNDING: The National Natural Science Foundation of China (Key Program).
