Urine Macrophages Polarization Predicts Renal Function Recovery after Nephron-Sparing Surgery in Patients with Renal Cell Carcinoma

Abstract

Introduction: This study was conducted to investigate the underlying associations between urine macrophages polarization and renal function recovery after nephron-sparing surgery (NSS) in patients with renal cell carcinoma (RCC) and to explore the potential application values of urine macrophages polarization in predicting the severity of renal ischemia/reperfusion injury (RIRI). Methods: Sixty-two patients with unilateral RCC who underwent NSS in our departments were prospectively recorded and followed up for long-term renal function to assess the onset of acute kidney injury (AKI) and chronic kidney disease (CKD). Urine samples of patients were collected 72 h after surgery for analyzing pro-inflammatory (classically activated/M1) and pro-reparative (alternatively activated/M2) macrophages polarization by flow cytometry. The detailed correlations between urine macrophages polarization and renal function recovery after NSS were explored by statistical analyses. Results: The cumulative incidence of postoperative AKI was 27.4% (17/62), and 47.0% (8/17) of those eventually developed to CKD during the follow-up. The mean urine M1/M2 ratio was 10.54 ± 8.13 in the AKI group and 3.93 ± 3.10 in the non-AKI group, presenting a significant statistical difference (p < 0.0001). Meanwhile, the urine M1/M2 ratio presented amazing potential in predicting postoperative CKD as well, with a mean ratio of 12.54 ± 9.41 in the CKD group and 4.28 ± 3.21 in the non-CKD group (p < 0.0001). Though univariate analysis implied that urine M1/M2 ratio was a relevant factor of both postoperative AKI and CKD in NSS surgical patients, multivariate analysis did not show satisfying predicting potential in postoperative CKD, mainly due to the very limited candidates enrolled in this study. Conclusion: Urine macrophages polarization could predict renal function recovery after NSS in patients with RCC. The urine M1/M2 ratio might a potential biomarker of RIRI but needs to be further verified in clinical settings.