Urinary EGF and MCP-1 and risk of CKD after cardiac surgery.

BACKGROUND Assessment of risk for chronic kidney disease (CKD) after acute kidney injury (AKI) is based on a limited set of markers primarily reflecting glomerular function. We evaluated markers of cell integrity (EGF) and inflammation (monocyte chemoattractant protein-1 [MCP-1]) for predicting long-term kidney outcomes after cardiac surgery. METHODS We measured the urinary biomarkers EGF and MCP-1 in pre- and post-operative urine samples from 865 adult patients who underwent cardiac surgery from 2007-2010 at 2 sites in Canada and the United States and assessed their associations with the composite outcome of CKD incidence or progression. We also used single-cell (Sc) RNAseq of biopsies from patients with AKI to perform a transcriptomic analysis of programs that are coregulated with the genes encoding the 2 biomarkers. RESULTS Over a median (IQR) follow-up of 5.8 (4.2-7.1) years, 266 (30.8%) patients developed the composite CKD outcome. Post-operatively, higher levels of urinary EGF were protective and higher levels of MCP-1 were associated with the composite CKD outcome (adjusted HR 0.83, 95% CI 0.73-0.95 and 1.10, 95% CI 1.00-1.21, respectively). Intrarenal scRNAseq transcriptomes in patients with AKI-defined cell populations revealed concordant changes in EGF and MCP-1 levels and identified underlying molecular processes associated with loss of EGF expression and gain of CCL2 (encoding MCP-1) expression. CONCLUSION Urinary EGF and MCP-1 were each independently associated with CKD incidence or progression after cardiac surgery. These markers may serve as noninvasive indicators of tubular damage, supported by tissue transcriptomes and provide opportunity for novel interventions in cardiac surgery. TRIAL REGISTRATION ClinicalTrials.gov NCT00774137FUNDING. NIH (R01HL085757 to CRP) funded the TRIBE-AKI Consortium.