Elevated Soluble Urokinase Plasminogen Activator Receptor and Proenkephalin Serum Levels Predict the Development of Acute Kidney Injury after Cardiac Surgery

309 Background: In colorectal cancer (CRC), the liver is the most common site of metastasis. Surgical resection represents the standard potentially curative therapy for patients with colorectal liver metastases (CRLM). However, 5-year survival rates after resection do not exceed 50%, and despite existing preoperative stratification algorithms it is still not fully understood which patients benefit most from surgery. The soluble urokinase plasminogen activator receptor (suPAR) has recently evolved as a promising biomarker for distinct clinical conditions. Here, we examined a potential role of circulating suPAR as a biomarker in patients undergoing resection of CRLM. Methods: Expression levels of uPAR, the membrane-bound source of circulating suPAR, were analysed in tissue samples of CRLM using RT-PCR and IHC. SuPAR serum levels were measured by ELISA in 104 patients undergoing surgical resection of CRLM as well as 50 healthy controls. Results were correlated with clinical data. Results: In line with an upregulation of uPAR in the CRLM tissue, serum levels of suPAR were significantly elevated in patients with CRLM compared to healthy controls. Patients with preoperative suPAR serum levels above our defined ideal cut-off value of 4.83 ng/ml showed a strikingly reduced overall survival after resection of CRLM, which could be confirmed for right- and left-sided primary CRC. Importantly, none of these patients reached long-term survival compared to patients with preoperative suPAR serum concentrations below the cut-off value. Moreover, multivariate Cox-regression analysis revealed preoperative suPAR serum levels as an independent prognostic factor in this setting. Additionally, elevated preoperative suPAR but not creatinine levels were a predictor of acute kidney injury after CRLM resection, correlating with a longer postoperative hospitalization. Conclusions: Serum levels of suPAR represent a promising novel biomarker in patients with resectable CRLM that might help to guide preoperative treatment decisions with regards to patients’ outcome and the identification of patients particularly susceptible to postoperative acute kidney injury.

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FC 043SOLUBLE UROKINASE PLASMINOGEN ACTIVATOR RECEPTOR (SUPAR) DETERMINES OUTCOMES IN CLINICAL AND EXPERIMENTAL SEPTIC ACUTE KIDNEY INJURY

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfab119.003 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

Christian Nusshag ◽

Changli Wei ◽

Eunsil Hahm ◽

Roman Szudarek ◽

Florian Kälble ◽

...

Keyword(s):

Acute Kidney Injury ◽

Plasminogen Activator ◽

Critically Ill ◽

Critically Ill Patients ◽

Odds Ratio ◽

Kidney Injury ◽

Urokinase Plasminogen Activator ◽

Renal Outcome ◽

Urokinase Plasminogen Activator Receptor ◽

Plasminogen Activator Receptor

Abstract Background and Aims Sepsis is the main contributor to the development of acute kidney injury (AKI) in critically ill patients. Plasma soluble urokinase plasminogen activator receptor (suPAR) is a circulating risk factor for AKI and a new prognostic marker for renal outcome prediction. We analyzed the pathophysiological role and kinetic properties of suPAR in septic AKI in critically ill patients and in a murine model of septic AKI. Method 200 critically ill patients were enrolled prospectively after meeting Sepsis-3 criteria. Serum suPAR levels were measured at 0, 12, 24, 48, 72, 96, 120 and 168-hour after enrollment (n=1440) and the need for RRT within 7 days (predefined criteria) was assessed as the primary outcome measure. Polybacterial sepsis was induced by cecal slurry injection in three mouse strains, respectively wild type (WT, N=16), uPAR-knockout (KO, N=15), and suPAR transgenic overexpression (OE, N=14). Results No or mild AKI occurred in 62 patients (31.0%), moderate or severe AKI without the need for RRT in 102 patients (51.0%), criteria for RRT were met in 36 patients (18.0%) and 7 patients (3.5%) died within the 7-day period. Compared to all other maximum AKI stages and AKI disease courses within 7 days, patients requiring RRT showed significantly higher suPAR levels at all time-points. Patients with suPAR levels ≥ 12.7 ng/mL (highest quartile) had an unadjusted odds ratio (OR) of 9.73 (95% confidence interval [CI], 4.31-21.98) and an adjusted odds ratio of 5.22 (95% CI, 2.16-12.65) for the need for RRT; and 7.47 (95% CI, 3.54-15.74) and 4.44 (95% CI, 1.98-9.97) for RRT or death within 7 days compared to patients with levels < 12.7 ng/mL. Compared to KO mice, WT and OE mice showed a significantly greater impairment of renal function, structure and tubular apoptosis 24 hours after induction of sepsis. The inflammation levels with respect to Interleukin 6 were comparable between different strains. Kaplan-Meier analysis revealed a survival benefit of KO mice over OE mice within 24h (86.7% vs. 50.0%, p=0.033). Conclusion SuPAR distinguishes between divergent AKI stages/courses and the need for RRT at any time within 7 days after sepsis diagnosis. Our experimental data suggest that suPAR is a pathophysiological driver of septic AKI and may serve as a target for future interventional strategies.

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