MO948CHANGES OF SOLUBLE UROKINASE PLASMINOGEN ACTIVATOR RECEPTOR (SUPAR) AFTER CADAVERIC KIDNEY TRANSPLANTATION AND ASSOCIATION WITH KIDNEY FUNCTION
Authors: Macionyte Ruta Skaiste , Bardauskas Marius , Vaiciuniene Ruta , Bumblyte Inga Arune 
Published: May 2021

Abstract

Background and Aims
The soluble urokinase plasminogen activator receptor (suPAR), a marker of podocyte injury, has been implicated in pathogenesis of various kidney diseases, especially in focal segmental glomerulosclerosis. It correlates to the activation level of immune system. SuPAR predicted all course mortality in hemodialysis patients, but was not tested as a prognostic biomarker in kidney transplant patients.
The aim of this study was to evaluate changes of suPAR concentration after kidney transplantation and to test its relation to graft function.

Method
We examined patients, who underwent cadaveric kidney transplantation (Tx) from 2019/05/23 to 2020/07/30 in the Hospital of Lithuanian University of Health Sciences. We evaluated level of suPAR biomarker before Tx, 12 days after Tx and 3 months after Tx. We used the suPARnostic Quick Triage test by ViroGates (Medtech, Denmark) for testing suPAR concentration. The suPARnostic Quick Triage test is based on the lateral flow principle. The device consists of a nitrocellulose membrane with two immobilized antibody zones and a running buffer with gold particles. The quantitative results are read by the aLF Reader with a detection interval of 2-15 ng/mL suPAR. Data on serum creatinine level and eGFR were collected at the same time points. Creatinine was tested using Analyzer AU680, Beckman Coulter, USA (Kinetic Jaffe traceable to the IDMS reference method). The statistical data analysis was performed using SPSS 23.0 software.

Results
35 patients were included into the study, 57% of men and 43% of woman. Mean age of patients - 47±13.5 years. Mean suPAR level before transplantation was 8.7±4.2 ng/ml. It was a trend towards lower mean suPAR level 12 days after Tx (5.9±2.8 ng/ml, p=0.1) as compared to before Tx. It was significant decrease of suPAR level 3 months after Tx (3.9±1.1 ng/ml, p=0.003) as compared to before Tx. There was no suPAR relation to patient’s age. Serum creatinine and eGFR did not correlate with suPAR levels measured at the same time (before Tx, 12 days, and 3 months after Tx). We did not find relation between suPAR level before transplantation and creatinine level and eGFR 12 days after Tx. We found a significant negative correlation between suPAR level before transplantation and creatinine level 3 months after transplantation (r = -0.4, p = 0.049), but not eGFR 3 months after Tx. In a group of patients with eGFR ≥45 ml/min/1.73m2 3 months after transplantation mean suPAR level before Tx (9.5±4.3 ng/ml), after 12 days (5.8±2.6 ng/ml), and 3 months after Tx (3.8±0.87 ng/ml) was not different than in group of patients with eGFR &lt; 45 ml/min/1.73m2 (8±4.1 ng/ml, 5.2±3.5 ng/ml, 3.9±1.5 ng/ml accordingly), p&gt;0.05.

Conclusion
There was a significant gradual decrease of suPAR levels during 3 months after transplantation. No correlation of suPAR levels and transplanted kidney function was confirmed. A larger study is needed to assess whether suPAR could predict long term outcomes in kidney transplantation.